1 ## Copyright (C) 1996-2018 The Squid Software Foundation and contributors
3 ## Squid software is distributed under GPLv2+ license and includes
4 ## contributions from numerous individuals and organizations.
5 ## Please see the COPYING and CONTRIBUTORS files for details.
10 ----------------------------
12 This is the documentation for the Squid configuration file.
13 This documentation can also be found online at:
14 http://www.squid-cache.org/Doc/config/
16 You may wish to look at the Squid home page and wiki for the
17 FAQ and other documentation:
18 http://www.squid-cache.org/
19 http://wiki.squid-cache.org/SquidFaq
20 http://wiki.squid-cache.org/ConfigExamples
22 This documentation shows what the defaults for various directives
23 happen to be. If you don't need to change the default, you should
24 leave the line out of your squid.conf in most cases.
26 In some cases "none" refers to no default setting at all,
27 while in other cases it refers to the value of the option
28 - the comments for that keyword indicate if this is the case.
33 Configuration options can be included using the "include" directive.
34 Include takes a list of files to include. Quoting and wildcards are
39 include /path/to/included/file/squid.acl.config
41 Includes can be nested up to a hard-coded depth of 16 levels.
42 This arbitrary restriction is to prevent recursive include references
43 from causing Squid entering an infinite loop whilst trying to load
46 Values with byte units
48 Squid accepts size units on some size related directives. All
49 such directives are documented with a default value displaying
52 Units accepted by Squid are:
54 KB - Kilobyte (1024 bytes)
58 Values with spaces, quotes, and other special characters
60 Squid supports directive parameters with spaces, quotes, and other
61 special characters. Surround such parameters with "double quotes". Use
62 the configuration_includes_quoted_values directive to enable or
65 Squid supports reading configuration option parameters from external
66 files using the syntax:
67 parameters("/path/filename")
69 acl whitelist dstdomain parameters("/etc/squid/whitelist.txt")
71 Conditional configuration
73 If-statements can be used to make configuration directives
77 ... regular configuration directives ...
79 ... regular configuration directives ...]
82 The else part is optional. The keywords "if", "else", and "endif"
83 must be typed on their own lines, as if they were regular
84 configuration directives.
86 NOTE: An else-if condition is not supported.
88 These individual conditions types are supported:
91 Always evaluates to true.
93 Always evaluates to false.
95 Equality comparison of two integer numbers.
100 The following SMP-related preprocessor macros can be used.
102 ${process_name} expands to the current Squid process "name"
103 (e.g., squid1, squid2, or cache1).
105 ${process_number} expands to the current Squid process
106 identifier, which is an integer number (e.g., 1, 2, 3) unique
107 across all Squid processes of the current service instance.
109 ${service_name} expands into the current Squid service instance
110 name identifier which is provided by -n on the command line.
114 Logformat macros can be used in many places outside of the logformat
115 directive. In theory, all of the logformat codes can be used as %macros,
116 where they are supported. In practice, a %macro expands as a dash (-) when
117 the transaction does not yet have enough information and a value is needed.
119 There is no definitive list of what tokens are available at the various
120 stages of the transaction.
122 And some information may already be available to Squid but not yet
123 committed where the macro expansion code can access it (report
124 such instances!). The macro will be expanded into a single dash
125 ('-') in such cases. Not all macros have been tested.
129 # options still not yet ported from 2.7 to 3.x
130 NAME: broken_vary_encoding
133 This option is not yet supported by Squid-3.
139 This option is not yet supported by Squid-3.
145 This option is not yet supported by Squid-3.
148 NAME: external_refresh_check
151 This option is not yet supported by Squid-3.
154 NAME: location_rewrite_program location_rewrite_access location_rewrite_children location_rewrite_concurrency
157 This option is not yet supported by Squid-3.
160 NAME: refresh_stale_hit
163 This option is not yet supported by Squid-3.
166 # Options removed in 4.x
167 NAME: cache_peer_domain cache_host_domain
170 Replace with dstdomain ACLs and cache_peer_access.
176 Remove this line. The behaviour enabled by this is no longer needed.
179 NAME: sslproxy_cafile
182 Remove this line. Use tls_outgoing_options cafile= instead.
185 NAME: sslproxy_capath
188 Remove this line. Use tls_outgoing_options capath= instead.
191 NAME: sslproxy_cipher
194 Remove this line. Use tls_outgoing_options cipher= instead.
197 NAME: sslproxy_client_certificate
200 Remove this line. Use tls_outgoing_options cert= instead.
203 NAME: sslproxy_client_key
206 Remove this line. Use tls_outgoing_options key= instead.
212 Remove this line. Use tls_outgoing_options flags= instead.
215 NAME: sslproxy_options
218 Remove this line. Use tls_outgoing_options options= instead.
221 NAME: sslproxy_version
224 Remove this line. Use tls_outgoing_options options= instead.
227 # Options removed in 3.5
228 NAME: hierarchy_stoplist
231 Remove this line. Use always_direct or cache_peer_access ACLs instead if you need to prevent cache_peer use.
234 # Options removed in 3.4
238 Remove this line. Use acls with access_log directives to control access logging
244 Remove this line. Use acls with icap_log directives to control icap logging
247 # Options Removed in 3.3
248 NAME: ignore_ims_on_miss
251 Remove this line. The HTTP/1.1 feature is now configured by 'cache_miss_revalidate'.
254 # Options Removed in 3.2
255 NAME: chunked_request_body_max_size
258 Remove this line. Squid is now HTTP/1.1 compliant.
261 NAME: dns_v4_fallback
264 Remove this line. Squid performs a 'Happy Eyeballs' algorithm, the 'fallback' algorithm is no longer relevant.
267 NAME: emulate_httpd_log
270 Replace this with an access_log directive using the format 'common' or 'combined'.
276 Use a regular access.log with ACL limiting it to MISS events.
282 Remove this line. Configure FTP page display using the CSS controls in errorpages.css instead.
285 NAME: ignore_expect_100
288 Remove this line. The HTTP/1.1 feature is now fully supported by default.
294 Remove this option from your config. To log FQDN use %>A in the log format.
297 NAME: log_ip_on_direct
300 Remove this option from your config. To log server or peer names use %<A in the log format.
303 NAME: maximum_single_addr_tries
306 Replaced by connect_retries. The behaviour has changed, please read the documentation before altering.
309 NAME: referer_log referrer_log
312 Replace this with an access_log directive using the format 'referrer'.
318 Remove this line. The feature is supported by default in storage types where update is implemented.
321 NAME: url_rewrite_concurrency
324 Remove this line. Set the 'concurrency=' option of url_rewrite_children instead.
330 Replace this with an access_log directive using the format 'useragent'.
333 # Options Removed in 3.1
337 Remove this line. DNS is no longer tested on startup.
340 NAME: extension_methods
343 Remove this line. All valid methods for HTTP are accepted by default.
346 # 2.7 Options Removed/Replaced in 3.2
351 # 2.7 Options Removed/Replaced in 3.1
359 Remove this line. HTTP/1.1 is supported by default.
362 NAME: upgrade_http0.9
365 Remove this line. ICY/1.0 streaming protocol is supported by default.
368 NAME: zph_local zph_mode zph_option zph_parent zph_sibling
371 Alter these entries. Use the qos_flows directive instead.
374 # Options Removed in 3.0
378 Since squid-3.0 replace with request_header_access or reply_header_access
379 depending on whether you wish to match client requests or server replies.
382 NAME: httpd_accel_no_pmtu_disc
385 Since squid-3.0 use the 'disable-pmtu-discovery' flag on http_port instead.
388 NAME: wais_relay_host
391 Replace this line with 'cache_peer' configuration.
394 NAME: wais_relay_port
397 Replace this line with 'cache_peer' configuration.
402 -----------------------------------------------------------------------------
409 DEFAULT_DOC: SMP support disabled.
411 Number of main Squid processes or "workers" to fork and maintain.
412 0: "no daemon" mode, like running "squid -N ..."
413 1: "no SMP" mode, start one main Squid process daemon (default)
414 N: start N main Squid process daemons (i.e., SMP mode)
416 In SMP mode, each worker does nearly all what a single Squid daemon
417 does (e.g., listen on http_port and forward HTTP requests).
420 NAME: cpu_affinity_map
422 LOC: Config.cpuAffinityMap
424 DEFAULT_DOC: Let operating system decide.
426 Usage: cpu_affinity_map process_numbers=P1,P2,... cores=C1,C2,...
428 Sets 1:1 mapping between Squid processes and CPU cores. For example,
430 cpu_affinity_map process_numbers=1,2,3,4 cores=1,3,5,7
432 affects processes 1 through 4 only and places them on the first
433 four even cores, starting with core #1.
435 CPU cores are numbered starting from 1. Requires support for
436 sched_getaffinity(2) and sched_setaffinity(2) system calls.
438 Multiple cpu_affinity_map options are merged.
443 NAME: shared_memory_locking
446 LOC: Config.shmLocking
449 Whether to ensure that all required shared memory is available by
450 "locking" that shared memory into RAM when Squid starts. The
451 alternative is faster startup time followed by slightly slower
452 performance and, if not enough RAM is actually available during
453 runtime, mysterious crashes.
455 SMP Squid uses many shared memory segments. These segments are
456 brought into Squid memory space using an mmap(2) system call. During
457 Squid startup, the mmap() call often succeeds regardless of whether
458 the system has enough RAM. In general, Squid cannot tell whether the
459 kernel applies this "optimistic" memory allocation policy (but
460 popular modern kernels usually use it).
462 Later, if Squid attempts to actually access the mapped memory
463 regions beyond what the kernel is willing to allocate, the
464 "optimistic" kernel simply kills Squid kid with a SIGBUS signal.
465 Some of the memory limits enforced by the kernel are currently
466 poorly understood: We do not know how to detect and check them. This
467 option ensures that the mapped memory will be available.
469 This option may have a positive performance side-effect: Locking
470 memory at start avoids runtime paging I/O. Paging slows Squid down.
472 Locking memory may require a large enough RLIMIT_MEMLOCK OS limit,
473 CAP_IPC_LOCK capability, or equivalent.
476 NAME: hopeless_kid_revival_delay
479 LOC: Config.hopelessKidRevivalDelay
482 Normally, when a kid process dies, Squid immediately restarts the
483 kid. A kid experiencing frequent deaths is marked as "hopeless" for
484 the duration specified by this directive. Hopeless kids are not
485 automatically restarted.
487 Currently, zero values are not supported because they result in
488 misconfigured SMP Squid instances running forever, endlessly
489 restarting each dying kid. To effectively disable hopeless kids
490 revival, set the delay to a huge value (e.g., 1 year).
492 Reconfiguration also clears all hopeless kids designations, allowing
493 for manual revival of hopeless kids.
497 OPTIONS FOR AUTHENTICATION
498 -----------------------------------------------------------------------------
504 LOC: Auth::TheConfig.schemes
507 This is used to define parameters for the various authentication
508 schemes supported by Squid.
510 format: auth_param scheme parameter [setting]
512 The order in which authentication schemes are presented to the client is
513 dependent on the order the scheme first appears in config file. IE
514 has a bug (it's not RFC 2617 compliant) in that it will use the basic
515 scheme if basic is the first entry presented, even if more secure
516 schemes are presented. For now use the order in the recommended
517 settings section below. If other browsers have difficulties (don't
518 recognize the schemes offered even if you are using basic) either
519 put basic first, or disable the other schemes (by commenting out their
522 Once an authentication scheme is fully configured, it can only be
523 shutdown by shutting squid down and restarting. Changes can be made on
524 the fly and activated with a reconfigure. I.E. You can change to a
525 different helper, but not unconfigure the helper completely.
527 Please note that while this directive defines how Squid processes
528 authentication it does not automatically activate authentication.
529 To use authentication you must in addition make use of ACLs based
530 on login name in http_access (proxy_auth, proxy_auth_regex or
531 external with %LOGIN used in the format tag). The browser will be
532 challenged for authentication on the first such acl encountered
533 in http_access processing and will also be re-challenged for new
534 login credentials if the request is being denied by a proxy_auth
537 WARNING: authentication can't be used in a transparently intercepting
538 proxy as the client then thinks it is talking to an origin server and
539 not the proxy. This is a limitation of bending the TCP/IP protocol to
540 transparently intercepting port 80, not a limitation in Squid.
541 Ports flagged 'transparent', 'intercept', or 'tproxy' have
542 authentication disabled.
544 === Parameters common to all schemes. ===
547 Specifies the command for the external authenticator.
549 By default, each authentication scheme is not used unless a
550 program is specified.
552 See http://wiki.squid-cache.org/Features/AddonHelpers for
553 more details on helper operations and creating your own.
556 Specifies a string to be append to request line format for
557 the authentication helper. "Quoted" format values may contain
558 spaces and logformat %macros. In theory, any logformat %macro
559 can be used. In practice, a %macro expands as a dash (-) if
560 the helper request is sent before the required macro
561 information is available to Squid.
563 By default, Squid uses request formats provided in
564 scheme-specific examples below (search for %credentials).
566 The expanded key_extras value is added to the Squid credentials
567 cache and, hence, will affect authentication. It can be used to
568 autenticate different users with identical user names (e.g.,
569 when user authentication depends on http_port).
571 Avoid adding frequently changing information to key_extras. For
572 example, if you add user source IP, and it changes frequently
573 in your environment, then max_user_ip ACL is going to treat
574 every user+IP combination as a unique "user", breaking the ACL
575 and wasting a lot of memory on those user records. It will also
576 force users to authenticate from scratch whenever their IP
580 Specifies the protection scope (aka realm name) which is to be
581 reported to the client for the authentication scheme. It is
582 commonly part of the text the user will see when prompted for
583 their username and password.
585 For Basic the default is "Squid proxy-caching web server".
586 For Digest there is no default, this parameter is mandatory.
587 For NTLM and Negotiate this parameter is ignored.
589 "children" numberofchildren [startup=N] [idle=N] [concurrency=N]
590 [queue-size=N] [on-persistent-overload=action]
592 The maximum number of authenticator processes to spawn. If
593 you start too few Squid will have to wait for them to process
594 a backlog of credential verifications, slowing it down. When
595 password verifications are done via a (slow) network you are
596 likely to need lots of authenticator processes.
598 The startup= and idle= options permit some skew in the exact
599 amount run. A minimum of startup=N will begin during startup
600 and reconfigure. Squid will start more in groups of up to
601 idle=N in an attempt to meet traffic needs and to keep idle=N
602 free above those traffic needs up to the maximum.
604 The concurrency= option sets the number of concurrent requests
605 the helper can process. The default of 0 is used for helpers
606 who only supports one request at a time. Setting this to a
607 number greater than 0 changes the protocol used to include a
608 channel ID field first on the request/response line, allowing
609 multiple requests to be sent to the same helper in parallel
610 without waiting for the response.
612 Concurrency must not be set unless it's known the helper
613 supports the input format with channel-ID fields.
615 The queue-size=N option sets the maximum number of queued
616 requests to N. The default maximum is 2*numberofchildren. Squid
617 is allowed to temporarily exceed the configured maximum, marking
618 the affected helper as "overloaded". If the helper overload
619 lasts more than 3 minutes, the action prescribed by the
620 on-persistent-overload option applies.
622 The on-persistent-overload=action option specifies Squid
623 reaction to a new helper request arriving when the helper
624 has been overloaded for more that 3 minutes already. The number
625 of queued requests determines whether the helper is overloaded
626 (see the queue-size option).
628 Two actions are supported:
630 die Squid worker quits. This is the default behavior.
632 ERR Squid treats the helper request as if it was
633 immediately submitted, and the helper immediately
634 replied with an ERR response. This action has no effect
635 on the already queued and in-progress helper requests.
637 NOTE: NTLM and Negotiate schemes do not support concurrency
638 in the Squid code module even though some helpers can.
641 If you experience problems with PUT/POST requests when using
642 the NTLM or Negotiate schemes then you can try setting this
643 to off. This will cause Squid to forcibly close the connection
644 on the initial request where the browser asks which schemes
645 are supported by the proxy.
647 For Basic and Digest this parameter is ignored.
650 HTTP uses iso-latin-1 as character set, while some
651 authentication backends such as LDAP expects UTF-8. If this is
652 set to on Squid will translate the HTTP iso-latin-1 charset to
653 UTF-8 before sending the username and password to the helper.
655 For NTLM and Negotiate this parameter is ignored.
657 IF HAVE_AUTH_MODULE_BASIC
658 === Basic authentication parameters ===
660 "credentialsttl" timetolive
661 Specifies how long squid assumes an externally validated
662 username:password pair is valid for - in other words how
663 often the helper program is called for that user. Set this
664 low to force revalidation with short lived passwords.
666 NOTE: setting this high does not impact your susceptibility
667 to replay attacks unless you are using an one-time password
668 system (such as SecureID). If you are using such a system,
669 you will be vulnerable to replay attacks unless you also
670 use the max_user_ip ACL in an http_access rule.
672 "casesensitive" on|off
673 Specifies if usernames are case sensitive. Most user databases
674 are case insensitive allowing the same username to be spelled
675 using both lower and upper case letters, but some are case
676 sensitive. This makes a big difference for user_max_ip ACL
677 processing and similar.
680 IF HAVE_AUTH_MODULE_DIGEST
681 === Digest authentication parameters ===
683 "nonce_garbage_interval" timeinterval
684 Specifies the interval that nonces that have been issued
685 to client_agent's are checked for validity.
687 "nonce_max_duration" timeinterval
688 Specifies the maximum length of time a given nonce will be
691 "nonce_max_count" number
692 Specifies the maximum number of times a given nonce can be
695 "nonce_strictness" on|off
696 Determines if squid requires strict increment-by-1 behavior
697 for nonce counts, or just incrementing (off - for use when
698 user agents generate nonce counts that occasionally miss 1
699 (ie, 1,2,4,6)). Default off.
701 "check_nonce_count" on|off
702 This directive if set to off can disable the nonce count check
703 completely to work around buggy digest qop implementations in
704 certain mainstream browser versions. Default on to check the
705 nonce count to protect from authentication replay attacks.
707 "post_workaround" on|off
708 This is a workaround to certain buggy browsers who send an
709 incorrect request digest in POST requests when reusing the
710 same nonce as acquired earlier on a GET request.
714 === Example Configuration ===
716 This configuration displays the recommended authentication scheme
717 order from most to least secure with recommended minimum configuration
718 settings for each scheme:
720 #auth_param negotiate program <uncomment and complete this line to activate>
721 #auth_param negotiate children 20 startup=0 idle=1
723 #auth_param digest program <uncomment and complete this line to activate>
724 #auth_param digest children 20 startup=0 idle=1
725 #auth_param digest realm Squid proxy-caching web server
726 #auth_param digest nonce_garbage_interval 5 minutes
727 #auth_param digest nonce_max_duration 30 minutes
728 #auth_param digest nonce_max_count 50
730 #auth_param ntlm program <uncomment and complete this line to activate>
731 #auth_param ntlm children 20 startup=0 idle=1
733 #auth_param basic program <uncomment and complete this line>
734 #auth_param basic children 5 startup=5 idle=1
735 #auth_param basic credentialsttl 2 hours
738 NAME: authenticate_cache_garbage_interval
742 LOC: Auth::TheConfig.garbageCollectInterval
744 The time period between garbage collection across the username cache.
745 This is a trade-off between memory utilization (long intervals - say
746 2 days) and CPU (short intervals - say 1 minute). Only change if you
750 NAME: authenticate_ttl
754 LOC: Auth::TheConfig.credentialsTtl
756 The time a user & their credentials stay in the logged in
757 user cache since their last request. When the garbage
758 interval passes, all user credentials that have passed their
759 TTL are removed from memory.
762 NAME: authenticate_ip_ttl
765 LOC: Auth::TheConfig.ipTtl
768 If you use proxy authentication and the 'max_user_ip' ACL,
769 this directive controls how long Squid remembers the IP
770 addresses associated with each user. Use a small value
771 (e.g., 60 seconds) if your users might change addresses
772 quickly, as is the case with dialup. You might be safe
773 using a larger value (e.g., 2 hours) in a corporate LAN
774 environment with relatively static address assignments.
779 -----------------------------------------------------------------------------
782 NAME: external_acl_type
783 TYPE: externalAclHelper
784 LOC: Config.externalAclHelperList
787 This option defines external acl classes using a helper program
788 to look up the status
790 external_acl_type name [options] FORMAT /path/to/helper [helper arguments]
794 ttl=n TTL in seconds for cached results (defaults to 3600
798 TTL for cached negative lookups (default same
801 grace=n Percentage remaining of TTL where a refresh of a
802 cached entry should be initiated without needing to
803 wait for a new reply. (default is for no grace period)
805 cache=n The maximum number of entries in the result cache. The
806 default limit is 262144 entries. Each cache entry usually
807 consumes at least 256 bytes. Squid currently does not remove
808 expired cache entries until the limit is reached, so a proxy
809 will sooner or later reach the limit. The expanded FORMAT
810 value is used as the cache key, so if the details in FORMAT
811 are highly variable, a larger cache may be needed to produce
812 reduction in helper load.
815 Maximum number of acl helper processes spawned to service
816 external acl lookups of this type. (default 5)
819 Minimum number of acl helper processes to spawn during
820 startup and reconfigure to service external acl lookups
821 of this type. (default 0)
824 Number of acl helper processes to keep ahead of traffic
825 loads. Squid will spawn this many at once whenever load
826 rises above the capabilities of existing processes.
827 Up to the value of children-max. (default 1)
829 concurrency=n concurrency level per process. Only used with helpers
830 capable of processing more than one query at a time.
832 queue-size=N The queue-size= option sets the maximum number of queued
833 requests. If the queued requests exceed queue size
835 The default value is set to 2*children-max.
837 protocol=2.5 Compatibility mode for Squid-2.5 external acl helpers.
839 ipv4 / ipv6 IP protocol used to communicate with this helper.
840 The default is to auto-detect IPv6 and use it when available.
843 FORMAT is a series of %macro codes. See logformat directive for a full list
844 of the accepted codes. Although note that at the time of any external ACL
845 being tested data may not be available and thus some %macro expand to '-'.
847 In addition to the logformat codes; when processing external ACLs these
848 additional macros are made available:
850 %ACL The name of the ACL being tested.
852 %DATA The ACL arguments specified in the referencing config
853 'acl ... external' line, separated by spaces (an
854 "argument string"). see acl external.
856 If there are no ACL arguments %DATA expands to '-'.
858 If you do not specify a DATA macro inside FORMAT,
859 Squid automatically appends %DATA to your FORMAT.
861 By default, Squid applies URL-encoding to each ACL
862 argument inside the argument string. If an explicit
863 encoding modifier is used (e.g., %#DATA), then Squid
864 encodes the whole argument string as a single token
865 (e.g., with %#DATA, spaces between arguments become
868 If SSL is enabled, the following formating codes become available:
870 %USER_CERT SSL User certificate in PEM format
871 %USER_CERTCHAIN SSL User certificate chain in PEM format
872 %USER_CERT_xx SSL User certificate subject attribute xx
873 %USER_CA_CERT_xx SSL User certificate issuer attribute xx
876 NOTE: all other format codes accepted by older Squid versions
880 General request syntax:
882 [channel-ID] FORMAT-values
885 FORMAT-values consists of transaction details expanded with
886 whitespace separation per the config file FORMAT specification
887 using the FORMAT macros listed above.
889 Request values sent to the helper are URL escaped to protect
890 each value in requests against whitespaces.
892 If using protocol=2.5 then the request sent to the helper is not
893 URL escaped to protect against whitespace.
895 NOTE: protocol=3.0 is deprecated as no longer necessary.
897 When using the concurrency= option the protocol is changed by
898 introducing a query channel tag in front of the request/response.
899 The query channel tag is a number between 0 and concurrency-1.
900 This value must be echoed back unchanged to Squid as the first part
901 of the response relating to its request.
904 The helper receives lines expanded per the above format specification
905 and for each input line returns 1 line starting with OK/ERR/BH result
906 code and optionally followed by additional keywords with more details.
909 General result syntax:
911 [channel-ID] result keyword=value ...
913 Result consists of one of the codes:
916 the ACL test produced a match.
919 the ACL test does not produce a match.
922 An internal error occurred in the helper, preventing
923 a result being identified.
925 The meaning of 'a match' is determined by your squid.conf
926 access control configuration. See the Squid wiki for details.
930 user= The users name (login)
932 password= The users password (for login= cache_peer option)
934 message= Message describing the reason for this response.
935 Available as %o in error pages.
936 Useful on (ERR and BH results).
938 tag= Apply a tag to a request. Only sets a tag once,
939 does not alter existing tags.
941 log= String to be logged in access.log. Available as
942 %ea in logformat specifications.
944 clt_conn_tag= Associates a TAG with the client TCP connection.
945 Please see url_rewrite_program related documentation
948 Any keywords may be sent on any response whether OK, ERR or BH.
950 All response keyword values need to be a single token with URL
951 escaping, or enclosed in double quotes (") and escaped using \ on
952 any double quotes or \ characters within the value. The wrapping
953 double quotes are removed before the value is interpreted by Squid.
954 \r and \n are also replace by CR and LF.
956 Some example key values:
960 user="J. \"Bob\" Smith"
967 DEFAULT: ssl::certHasExpired ssl_error X509_V_ERR_CERT_HAS_EXPIRED
968 DEFAULT: ssl::certNotYetValid ssl_error X509_V_ERR_CERT_NOT_YET_VALID
969 DEFAULT: ssl::certDomainMismatch ssl_error SQUID_X509_V_ERR_DOMAIN_MISMATCH
970 DEFAULT: ssl::certUntrusted ssl_error X509_V_ERR_INVALID_CA X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN X509_V_ERR_UNABLE_TO_VERIFY_LEAF_SIGNATURE X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY X509_V_ERR_CERT_UNTRUSTED
971 DEFAULT: ssl::certSelfSigned ssl_error X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT
974 DEFAULT: manager url_regex -i ^cache_object:// +i ^https?://[^/]+/squid-internal-mgr/
975 DEFAULT: localhost src 127.0.0.1/32 ::1
976 DEFAULT: to_localhost dst 127.0.0.0/8 0.0.0.0/32 ::1
977 DEFAULT: CONNECT method CONNECT
978 DEFAULT_DOC: ACLs all, manager, localhost, to_localhost, and CONNECT are predefined.
980 Defining an Access List
982 Every access list definition must begin with an aclname and acltype,
983 followed by either type-specific arguments or a quoted filename that
986 acl aclname acltype argument ...
987 acl aclname acltype "file" ...
989 When using "file", the file should contain one item per line.
994 Some acl types supports options which changes their default behaviour:
996 -i,+i By default, regular expressions are CASE-SENSITIVE. To make them
997 case-insensitive, use the -i option. To return case-sensitive
998 use the +i option between patterns, or make a new ACL line
1001 -n Disable lookups and address type conversions. If lookup or
1002 conversion is required because the parameter type (IP or
1003 domain name) does not match the message address type (domain
1004 name or IP), then the ACL would immediately declare a mismatch
1005 without any warnings or lookups.
1008 Perform a list membership test, interpreting values as
1009 comma-separated token lists and matching against individual
1010 tokens instead of whole values.
1011 The optional "delimiters" parameter specifies one or more
1012 alternative non-alphanumeric delimiter characters.
1013 non-alphanumeric delimiter characters.
1015 -- Used to stop processing all options, in the case the first acl
1016 value has '-' character as first character (for example the '-'
1017 is a valid domain name)
1019 Some acl types require suspending the current request in order
1020 to access some external data source.
1021 Those which do are marked with the tag [slow], those which
1022 don't are marked as [fast].
1023 See http://wiki.squid-cache.org/SquidFaq/SquidAcl
1024 for further information
1026 ***** ACL TYPES AVAILABLE *****
1028 acl aclname src ip-address/mask ... # clients IP address [fast]
1029 acl aclname src addr1-addr2/mask ... # range of addresses [fast]
1030 acl aclname dst [-n] ip-address/mask ... # URL host's IP address [slow]
1031 acl aclname localip ip-address/mask ... # IP address the client connected to [fast]
1034 acl aclname arp mac-address ...
1035 acl aclname eui64 eui64-address ...
1037 # MAC (EUI-48) and EUI-64 addresses use xx:xx:xx:xx:xx:xx notation.
1039 # The 'arp' ACL code is not portable to all operating systems.
1040 # It works on Linux, Solaris, Windows, FreeBSD, and some other
1043 # The eui_lookup directive is required to be 'on' (the default)
1044 # and Squid built with --enable-eui for MAC/EUI addresses to be
1045 # available for this ACL.
1047 # Squid can only determine the MAC/EUI address for IPv4
1048 # clients that are on the same subnet. If the client is on a
1049 # different subnet, then Squid cannot find out its address.
1051 # IPv6 protocol does not contain ARP. MAC/EUI is either
1052 # encoded directly in the IPv6 address or not available.
1054 acl aclname clientside_mark mark[/mask] ...
1055 # matches CONNMARK of an accepted connection [fast]
1056 # DEPRECATED. Use the 'client_connection_mark' instead.
1058 acl aclname client_connection_mark mark[/mask] ...
1059 # matches CONNMARK of an accepted connection [fast]
1061 # mark and mask are unsigned integers (hex, octal, or decimal).
1062 # If multiple marks are given, then the ACL matches if at least
1065 # Uses netfilter-conntrack library.
1066 # Requires building Squid with --enable-linux-netfilter.
1068 # The client, various intermediaries, and Squid itself may set
1069 # CONNMARK at various times. The last CONNMARK set wins. This ACL
1070 # checks the mark present on an accepted connection or set by
1071 # Squid afterwards, depending on the ACL check timing. This ACL
1072 # effectively ignores any mark set by other agents after Squid has
1073 # accepted the connection.
1075 acl aclname srcdomain .foo.com ...
1076 # reverse lookup, from client IP [slow]
1077 acl aclname dstdomain [-n] .foo.com ...
1078 # Destination server from URL [fast]
1079 acl aclname srcdom_regex [-i] \.foo\.com ...
1080 # regex matching client name [slow]
1081 acl aclname dstdom_regex [-n] [-i] \.foo\.com ...
1082 # regex matching server [fast]
1084 # For dstdomain and dstdom_regex a reverse lookup is tried if a IP
1085 # based URL is used and no match is found. The name "none" is used
1086 # if the reverse lookup fails.
1088 acl aclname src_as number ...
1089 acl aclname dst_as number ...
1091 # Except for access control, AS numbers can be used for
1092 # routing of requests to specific caches. Here's an
1093 # example for routing all requests for AS#1241 and only
1094 # those to mycache.mydomain.net:
1095 # acl asexample dst_as 1241
1096 # cache_peer_access mycache.mydomain.net allow asexample
1097 # cache_peer_access mycache_mydomain.net deny all
1099 acl aclname peername myPeer ...
1100 acl aclname peername_regex [-i] regex-pattern ...
1102 # match against a named cache_peer entry
1103 # set unique name= on cache_peer lines for reliable use.
1105 acl aclname time [day-abbrevs] [h1:m1-h2:m2]
1115 # h1:m1 must be less than h2:m2
1117 acl aclname url_regex [-i] ^http:// ...
1118 # regex matching on whole URL [fast]
1119 acl aclname urllogin [-i] [^a-zA-Z0-9] ...
1120 # regex matching on URL login field
1121 acl aclname urlpath_regex [-i] \.gif$ ...
1122 # regex matching on URL path [fast]
1124 acl aclname port 80 70 21 0-1024... # destination TCP port [fast]
1126 acl aclname localport 3128 ... # TCP port the client connected to [fast]
1127 # NP: for interception mode this is usually '80'
1129 acl aclname myportname 3128 ... # *_port name [fast]
1131 acl aclname proto HTTP FTP ... # request protocol [fast]
1133 acl aclname method GET POST ... # HTTP request method [fast]
1135 acl aclname http_status 200 301 500- 400-403 ...
1136 # status code in reply [fast]
1138 acl aclname browser [-i] regexp ...
1139 # pattern match on User-Agent header (see also req_header below) [fast]
1141 acl aclname referer_regex [-i] regexp ...
1142 # pattern match on Referer header [fast]
1143 # Referer is highly unreliable, so use with care
1145 acl aclname ident [-i] username ...
1146 acl aclname ident_regex [-i] pattern ...
1147 # string match on ident output [slow]
1148 # use REQUIRED to accept any non-null ident.
1150 acl aclname proxy_auth [-i] username ...
1151 acl aclname proxy_auth_regex [-i] pattern ...
1152 # perform http authentication challenge to the client and match against
1153 # supplied credentials [slow]
1155 # takes a list of allowed usernames.
1156 # use REQUIRED to accept any valid username.
1158 # Will use proxy authentication in forward-proxy scenarios, and plain
1159 # http authenticaiton in reverse-proxy scenarios
1161 # NOTE: when a Proxy-Authentication header is sent but it is not
1162 # needed during ACL checking the username is NOT logged
1165 # NOTE: proxy_auth requires a EXTERNAL authentication program
1166 # to check username/password combinations (see
1167 # auth_param directive).
1169 # NOTE: proxy_auth can't be used in a transparent/intercepting proxy
1170 # as the browser needs to be configured for using a proxy in order
1171 # to respond to proxy authentication.
1173 acl aclname snmp_community string ...
1174 # A community string to limit access to your SNMP Agent [fast]
1177 # acl snmppublic snmp_community public
1179 acl aclname maxconn number
1180 # This will be matched when the client's IP address has
1181 # more than <number> TCP connections established. [fast]
1182 # NOTE: This only measures direct TCP links so X-Forwarded-For
1183 # indirect clients are not counted.
1185 acl aclname max_user_ip [-s] number
1186 # This will be matched when the user attempts to log in from more
1187 # than <number> different ip addresses. The authenticate_ip_ttl
1188 # parameter controls the timeout on the ip entries. [fast]
1189 # If -s is specified the limit is strict, denying browsing
1190 # from any further IP addresses until the ttl has expired. Without
1191 # -s Squid will just annoy the user by "randomly" denying requests.
1192 # (the counter is reset each time the limit is reached and a
1193 # request is denied)
1194 # NOTE: in acceleration mode or where there is mesh of child proxies,
1195 # clients may appear to come from multiple addresses if they are
1196 # going through proxy farms, so a limit of 1 may cause user problems.
1198 acl aclname random probability
1199 # Pseudo-randomly match requests. Based on the probability given.
1200 # Probability may be written as a decimal (0.333), fraction (1/3)
1201 # or ratio of matches:non-matches (3:5).
1203 acl aclname req_mime_type [-i] mime-type ...
1204 # regex match against the mime type of the request generated
1205 # by the client. Can be used to detect file upload or some
1206 # types HTTP tunneling requests [fast]
1207 # NOTE: This does NOT match the reply. You cannot use this
1208 # to match the returned file type.
1210 acl aclname req_header header-name [-i] any\.regex\.here
1211 # regex match against any of the known request headers. May be
1212 # thought of as a superset of "browser", "referer" and "mime-type"
1215 acl aclname rep_mime_type [-i] mime-type ...
1216 # regex match against the mime type of the reply received by
1217 # squid. Can be used to detect file download or some
1218 # types HTTP tunneling requests. [fast]
1219 # NOTE: This has no effect in http_access rules. It only has
1220 # effect in rules that affect the reply data stream such as
1221 # http_reply_access.
1223 acl aclname rep_header header-name [-i] any\.regex\.here
1224 # regex match against any of the known reply headers. May be
1225 # thought of as a superset of "browser", "referer" and "mime-type"
1228 acl aclname external class_name [arguments...]
1229 # external ACL lookup via a helper class defined by the
1230 # external_acl_type directive [slow]
1232 acl aclname user_cert attribute values...
1233 # match against attributes in a user SSL certificate
1234 # attribute is one of DN/C/O/CN/L/ST or a numerical OID [fast]
1236 acl aclname ca_cert attribute values...
1237 # match against attributes a users issuing CA SSL certificate
1238 # attribute is one of DN/C/O/CN/L/ST or a numerical OID [fast]
1240 acl aclname ext_user [-i] username ...
1241 acl aclname ext_user_regex [-i] pattern ...
1242 # string match on username returned by external acl helper [slow]
1243 # use REQUIRED to accept any non-null user name.
1245 acl aclname tag tagvalue ...
1246 # string match on tag returned by external acl helper [fast]
1247 # DEPRECATED. Only the first tag will match with this ACL.
1248 # Use the 'note' ACL instead for handling multiple tag values.
1250 acl aclname hier_code codename ...
1251 # string match against squid hierarchy code(s); [fast]
1252 # e.g., DIRECT, PARENT_HIT, NONE, etc.
1254 # NOTE: This has no effect in http_access rules. It only has
1255 # effect in rules that affect the reply data stream such as
1256 # http_reply_access.
1258 acl aclname note [-m[=delimiters]] name [value ...]
1259 # match transaction annotation [fast]
1260 # Without values, matches any annotation with a given name.
1261 # With value(s), matches any annotation with a given name that
1262 # also has one of the given values.
1263 # If the -m flag is used, then the value of the named
1264 # annotation is interpreted as a list of tokens, and the ACL
1265 # matches individual name=token pairs rather than whole
1266 # name=value pairs. See "ACL Options" above for more info.
1267 # Annotation sources include note and adaptation_meta directives
1268 # as well as helper and eCAP responses.
1270 acl aclname annotate_transaction [-m[=delimiters]] key=value ...
1271 acl aclname annotate_transaction [-m[=delimiters]] key+=value ...
1272 # Always matches. [fast]
1273 # Used for its side effect: This ACL immediately adds a
1274 # key=value annotation to the current master transaction.
1275 # The added annotation can then be tested using note ACL and
1276 # logged (or sent to helpers) using %note format code.
1278 # Annotations can be specified using replacement and addition
1279 # formats. The key=value form replaces old same-key annotation
1280 # value(s). The key+=value form appends a new value to the old
1281 # same-key annotation. Both forms create a new key=value
1282 # annotation if no same-key annotation exists already. If
1283 # -m flag is used, then the value is interpreted as a list
1284 # and the annotation will contain key=token pair(s) instead of the
1285 # whole key=value pair.
1287 # This ACL is especially useful for recording complex multi-step
1288 # ACL-driven decisions. For example, the following configuration
1289 # avoids logging transactions accepted after aclX matched:
1291 # # First, mark transactions accepted after aclX matched
1292 # acl markSpecial annotate_transaction special=true
1293 # http_access allow acl001
1295 # http_access deny acl100
1296 # http_access allow aclX markSpecial
1298 # # Second, do not log marked transactions:
1299 # acl markedSpecial note special true
1300 # access_log ... deny markedSpecial
1302 # # Note that the following would not have worked because aclX
1303 # # alone does not determine whether the transaction was allowed:
1304 # access_log ... deny aclX # Wrong!
1306 # Warning: This ACL annotates the transaction even when negated
1307 # and even if subsequent ACLs fail to match. For example, the
1308 # following three rules will have exactly the same effect as far
1309 # as annotations set by the "mark" ACL are concerned:
1311 # some_directive acl1 ... mark # rule matches if mark is reached
1312 # some_directive acl1 ... !mark # rule never matches
1313 # some_directive acl1 ... mark !all # rule never matches
1315 acl aclname annotate_client [-m[=delimiters]] key=value ...
1316 acl aclname annotate_client [-m[=delimiters]] key+=value ...
1318 # Always matches. [fast]
1319 # Used for its side effect: This ACL immediately adds a
1320 # key=value annotation to the current client-to-Squid
1321 # connection. Connection annotations are propagated to the current
1322 # and all future master transactions on the annotated connection.
1323 # See the annotate_transaction ACL for details.
1325 # For example, the following configuration avoids rewriting URLs
1326 # of transactions bumped by SslBump:
1328 # # First, mark bumped connections:
1329 # acl markBumped annotate_client bumped=true
1330 # ssl_bump peek acl1
1331 # ssl_bump stare acl2
1332 # ssl_bump bump acl3 markBumped
1333 # ssl_bump splice all
1335 # # Second, do not send marked transactions to the redirector:
1336 # acl markedBumped note bumped true
1337 # url_rewrite_access deny markedBumped
1339 # # Note that the following would not have worked because acl3 alone
1340 # # does not determine whether the connection is going to be bumped:
1341 # url_rewrite_access deny acl3 # Wrong!
1343 acl aclname adaptation_service service ...
1344 # Matches the name of any icap_service, ecap_service,
1345 # adaptation_service_set, or adaptation_service_chain that Squid
1346 # has used (or attempted to use) for the master transaction.
1347 # This ACL must be defined after the corresponding adaptation
1348 # service is named in squid.conf. This ACL is usable with
1349 # adaptation_meta because it starts matching immediately after
1350 # the service has been selected for adaptation.
1352 acl aclname transaction_initiator initiator ...
1353 # Matches transaction's initiator [fast]
1355 # Supported initiators are:
1356 # esi: matches transactions fetching ESI resources
1357 # certificate-fetching: matches transactions fetching
1358 # a missing intermediate TLS certificate
1359 # cache-digest: matches transactions fetching Cache Digests
1361 # htcp: matches HTCP requests from peers
1362 # icp: matches ICP requests to peers
1363 # icmp: matches ICMP RTT database (NetDB) requests to peers
1364 # asn: matches asns db requests
1365 # internal: matches any of the above
1366 # client: matches transactions containing an HTTP or FTP
1367 # client request received at a Squid *_port
1368 # all: matches any transaction, including internal transactions
1369 # without a configurable initiator and hopefully rare
1370 # transactions without a known-to-Squid initiator
1372 # Multiple initiators are ORed.
1374 acl aclname has component
1375 # matches a transaction "component" [fast]
1377 # Supported transaction components are:
1378 # request: transaction has a request header (at least)
1379 # response: transaction has a response header (at least)
1380 # ALE: transaction has an internally-generated Access Log Entry
1381 # structure; bugs notwithstanding, all transaction have it
1383 # For example, the following configuration helps when dealing with HTTP
1384 # clients that close connections without sending a request header:
1386 # acl hasRequest has request
1387 # acl logMe note important_transaction
1388 # # avoid "logMe ACL is used in context without an HTTP request" warnings
1389 # access_log ... logformat=detailed hasRequest logMe
1390 # # log request-less transactions, instead of ignoring them
1391 # access_log ... logformat=brief !hasRequest
1393 # Multiple components are not supported for one "acl" rule, but
1394 # can be specified (and are ORed) using multiple same-name rules:
1396 # # OK, this strange logging daemon needs request or response,
1397 # # but can work without either a request or a response:
1398 # acl hasWhatMyLoggingDaemonNeeds has request
1399 # acl hasWhatMyLoggingDaemonNeeds has response
1402 acl aclname ssl_error errorname
1403 # match against SSL certificate validation error [fast]
1405 # For valid error names see in @DEFAULT_ERROR_DIR@/templates/error-details.txt
1408 # The following can be used as shortcuts for certificate properties:
1409 # [ssl::]certHasExpired: the "not after" field is in the past
1410 # [ssl::]certNotYetValid: the "not before" field is in the future
1411 # [ssl::]certUntrusted: The certificate issuer is not to be trusted.
1412 # [ssl::]certSelfSigned: The certificate is self signed.
1413 # [ssl::]certDomainMismatch: The certificate CN domain does not
1414 # match the name the name of the host we are connecting to.
1416 # The ssl::certHasExpired, ssl::certNotYetValid, ssl::certDomainMismatch,
1417 # ssl::certUntrusted, and ssl::certSelfSigned can also be used as
1418 # predefined ACLs, just like the 'all' ACL.
1420 # NOTE: The ssl_error ACL is only supported with sslproxy_cert_error,
1421 # sslproxy_cert_sign, and sslproxy_cert_adapt options.
1423 acl aclname server_cert_fingerprint [-sha1] fingerprint
1424 # match against server SSL certificate fingerprint [fast]
1426 # The fingerprint is the digest of the DER encoded version
1427 # of the whole certificate. The user should use the form: XX:XX:...
1428 # Optional argument specifies the digest algorithm to use.
1429 # The SHA1 digest algorithm is the default and is currently
1430 # the only algorithm supported (-sha1).
1432 acl aclname at_step step
1433 # match against the current step during ssl_bump evaluation [fast]
1434 # Never matches and should not be used outside the ssl_bump context.
1436 # At each SslBump step, Squid evaluates ssl_bump directives to find
1437 # the next bumping action (e.g., peek or splice). Valid SslBump step
1438 # values and the corresponding ssl_bump evaluation moments are:
1439 # SslBump1: After getting TCP-level and HTTP CONNECT info.
1440 # SslBump2: After getting SSL Client Hello info.
1441 # SslBump3: After getting SSL Server Hello info.
1443 acl aclname ssl::server_name [option] .foo.com ...
1444 # matches server name obtained from various sources [fast]
1446 # The ACL computes server name(s) using such information sources as
1447 # CONNECT request URI, TLS client SNI, and TLS server certificate
1448 # subject (CN and SubjectAltName). The computed server name(s) usually
1449 # change with each SslBump step, as more info becomes available:
1450 # * SNI is used as the server name instead of the request URI,
1451 # * subject name(s) from the server certificate (CN and
1452 # SubjectAltName) are used as the server names instead of SNI.
1454 # When the ACL computes multiple server names, matching any single
1455 # computed name is sufficient for the ACL to match.
1457 # The "none" name can be used to match transactions where the ACL
1458 # could not compute the server name using any information source
1459 # that was both available and allowed to be used by the ACL options at
1460 # the ACL evaluation time.
1462 # Unlike dstdomain, this ACL does not perform DNS lookups.
1464 # An ACL option below may be used to restrict what information
1465 # sources are used to extract the server names from:
1467 # --client-requested
1468 # The server name is SNI regardless of what the server says.
1470 # The server name(s) are the certificate subject name(s), regardless
1471 # of what the client has requested. If the server certificate is
1472 # unavailable, then the name is "none".
1474 # The server name is either SNI (if SNI matches at least one of the
1475 # certificate subject names) or "none" (otherwise). When the server
1476 # certificate is unavailable, the consensus server name is SNI.
1478 # Combining multiple options in one ACL is a fatal configuration
1481 # For all options: If no SNI is available, then the CONNECT request
1482 # target (a.k.a. URI) is used instead of SNI (for an intercepted
1483 # connection, this target is the destination IP address).
1485 acl aclname ssl::server_name_regex [-i] \.foo\.com ...
1486 # regex matches server name obtained from various sources [fast]
1488 acl aclname connections_encrypted
1489 # matches transactions with all HTTP messages received over TLS
1490 # transport connections. [fast]
1492 # The master transaction deals with HTTP messages received from
1493 # various sources. All sources used by the master transaction in the
1494 # past are considered by the ACL. The following rules define whether
1495 # a given message source taints the entire master transaction,
1496 # resulting in ACL mismatches:
1498 # * The HTTP client transport connection is not TLS.
1499 # * An adaptation service connection-encryption flag is off.
1500 # * The peer or origin server transport connection is not TLS.
1502 # Caching currently does not affect these rules. This cache ignorance
1503 # implies that only the current HTTP client transport and REQMOD
1504 # services status determine whether this ACL matches a from-cache
1505 # transaction. The source of the cached response does not have any
1506 # effect on future transaction that use the cached response without
1507 # revalidation. This may change.
1509 # DNS, ICP, and HTCP exchanges during the master transaction do not
1510 # affect these rules.
1512 acl aclname any-of acl1 acl2 ...
1513 # match any one of the acls [fast or slow]
1514 # The first matching ACL stops further ACL evaluation.
1516 # ACLs from multiple any-of lines with the same name are ORed.
1517 # For example, A = (a1 or a2) or (a3 or a4) can be written as
1518 # acl A any-of a1 a2
1519 # acl A any-of a3 a4
1521 # This group ACL is fast if all evaluated ACLs in the group are fast
1522 # and slow otherwise.
1524 acl aclname all-of acl1 acl2 ...
1525 # match all of the acls [fast or slow]
1526 # The first mismatching ACL stops further ACL evaluation.
1528 # ACLs from multiple all-of lines with the same name are ORed.
1529 # For example, B = (b1 and b2) or (b3 and b4) can be written as
1530 # acl B all-of b1 b2
1531 # acl B all-of b3 b4
1533 # This group ACL is fast if all evaluated ACLs in the group are fast
1534 # and slow otherwise.
1537 acl macaddress arp 09:00:2b:23:45:67
1538 acl myexample dst_as 1241
1539 acl password proxy_auth REQUIRED
1540 acl fileupload req_mime_type -i ^multipart/form-data$
1541 acl javascript rep_mime_type -i ^application/x-javascript$
1545 # Recommended minimum configuration:
1548 # Example rule allowing access from your local networks.
1549 # Adapt to list your (internal) IP networks from where browsing
1551 acl localnet src 0.0.0.1-0.255.255.255 # RFC 1122 "this" network (LAN)
1552 acl localnet src 10.0.0.0/8 # RFC 1918 local private network (LAN)
1553 acl localnet src 100.64.0.0/10 # RFC 6598 shared address space (CGN)
1554 acl localnet src 169.254.0.0/16 # RFC 3927 link-local (directly plugged) machines
1555 acl localnet src 172.16.0.0/12 # RFC 1918 local private network (LAN)
1556 acl localnet src 192.168.0.0/16 # RFC 1918 local private network (LAN)
1557 acl localnet src fc00::/7 # RFC 4193 local private network range
1558 acl localnet src fe80::/10 # RFC 4291 link-local (directly plugged) machines
1560 acl SSL_ports port 443
1561 acl Safe_ports port 80 # http
1562 acl Safe_ports port 21 # ftp
1563 acl Safe_ports port 443 # https
1564 acl Safe_ports port 70 # gopher
1565 acl Safe_ports port 210 # wais
1566 acl Safe_ports port 1025-65535 # unregistered ports
1567 acl Safe_ports port 280 # http-mgmt
1568 acl Safe_ports port 488 # gss-http
1569 acl Safe_ports port 591 # filemaker
1570 acl Safe_ports port 777 # multiling http
1574 NAME: proxy_protocol_access
1576 LOC: Config.accessList.proxyProtocol
1578 DEFAULT_DOC: all TCP connections to ports with require-proxy-header will be denied
1580 Determine which client proxies can be trusted to provide correct
1581 information regarding real client IP address using PROXY protocol.
1583 Requests may pass through a chain of several other proxies
1584 before reaching us. The original source details may by sent in:
1585 * HTTP message Forwarded header, or
1586 * HTTP message X-Forwarded-For header, or
1587 * PROXY protocol connection header.
1589 This directive is solely for validating new PROXY protocol
1590 connections received from a port flagged with require-proxy-header.
1591 It is checked only once after TCP connection setup.
1593 A deny match results in TCP connection closure.
1595 An allow match is required for Squid to permit the corresponding
1596 TCP connection, before Squid even looks for HTTP request headers.
1597 If there is an allow match, Squid starts using PROXY header information
1598 to determine the source address of the connection for all future ACL
1599 checks, logging, etc.
1601 SECURITY CONSIDERATIONS:
1603 Any host from which we accept client IP details can place
1604 incorrect information in the relevant header, and Squid
1605 will use the incorrect information as if it were the
1606 source address of the request. This may enable remote
1607 hosts to bypass any access control restrictions that are
1608 based on the client's source addresses.
1610 This clause only supports fast acl types.
1611 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1614 NAME: follow_x_forwarded_for
1616 IFDEF: FOLLOW_X_FORWARDED_FOR
1617 LOC: Config.accessList.followXFF
1618 DEFAULT_IF_NONE: deny all
1619 DEFAULT_DOC: X-Forwarded-For header will be ignored.
1621 Determine which client proxies can be trusted to provide correct
1622 information regarding real client IP address.
1624 Requests may pass through a chain of several other proxies
1625 before reaching us. The original source details may by sent in:
1626 * HTTP message Forwarded header, or
1627 * HTTP message X-Forwarded-For header, or
1628 * PROXY protocol connection header.
1630 PROXY protocol connections are controlled by the proxy_protocol_access
1631 directive which is checked before this.
1633 If a request reaches us from a source that is allowed by this
1634 directive, then we trust the information it provides regarding
1635 the IP of the client it received from (if any).
1637 For the purpose of ACLs used in this directive the src ACL type always
1638 matches the address we are testing and srcdomain matches its rDNS.
1640 On each HTTP request Squid checks for X-Forwarded-For header fields.
1641 If found the header values are iterated in reverse order and an allow
1642 match is required for Squid to continue on to the next value.
1643 The verification ends when a value receives a deny match, cannot be
1644 tested, or there are no more values to test.
1645 NOTE: Squid does not yet follow the Forwarded HTTP header.
1647 The end result of this process is an IP address that we will
1648 refer to as the indirect client address. This address may
1649 be treated as the client address for access control, ICAP, delay
1650 pools and logging, depending on the acl_uses_indirect_client,
1651 icap_uses_indirect_client, delay_pool_uses_indirect_client,
1652 log_uses_indirect_client and tproxy_uses_indirect_client options.
1654 This clause only supports fast acl types.
1655 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1657 SECURITY CONSIDERATIONS:
1659 Any host from which we accept client IP details can place
1660 incorrect information in the relevant header, and Squid
1661 will use the incorrect information as if it were the
1662 source address of the request. This may enable remote
1663 hosts to bypass any access control restrictions that are
1664 based on the client's source addresses.
1668 acl localhost src 127.0.0.1
1669 acl my_other_proxy srcdomain .proxy.example.com
1670 follow_x_forwarded_for allow localhost
1671 follow_x_forwarded_for allow my_other_proxy
1674 NAME: acl_uses_indirect_client
1677 IFDEF: FOLLOW_X_FORWARDED_FOR
1679 LOC: Config.onoff.acl_uses_indirect_client
1681 Controls whether the indirect client address
1682 (see follow_x_forwarded_for) is used instead of the
1683 direct client address in acl matching.
1685 NOTE: maxconn ACL considers direct TCP links and indirect
1686 clients will always have zero. So no match.
1689 NAME: delay_pool_uses_indirect_client
1692 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_DELAY_POOLS
1694 LOC: Config.onoff.delay_pool_uses_indirect_client
1696 Controls whether the indirect client address
1697 (see follow_x_forwarded_for) is used instead of the
1698 direct client address in delay pools.
1701 NAME: log_uses_indirect_client
1704 IFDEF: FOLLOW_X_FORWARDED_FOR
1706 LOC: Config.onoff.log_uses_indirect_client
1708 Controls whether the indirect client address
1709 (see follow_x_forwarded_for) is used instead of the
1710 direct client address in the access log.
1713 NAME: tproxy_uses_indirect_client
1716 IFDEF: FOLLOW_X_FORWARDED_FOR&&LINUX_NETFILTER
1718 LOC: Config.onoff.tproxy_uses_indirect_client
1720 Controls whether the indirect client address
1721 (see follow_x_forwarded_for) is used instead of the
1722 direct client address when spoofing the outgoing client.
1724 This has no effect on requests arriving in non-tproxy
1727 SECURITY WARNING: Usage of this option is dangerous
1728 and should not be used trivially. Correct configuration
1729 of follow_x_forwarded_for with a limited set of trusted
1730 sources is required to prevent abuse of your proxy.
1733 NAME: spoof_client_ip
1735 LOC: Config.accessList.spoof_client_ip
1737 DEFAULT_DOC: Allow spoofing on all TPROXY traffic.
1739 Control client IP address spoofing of TPROXY traffic based on
1740 defined access lists.
1742 spoof_client_ip allow|deny [!]aclname ...
1744 If there are no "spoof_client_ip" lines present, the default
1745 is to "allow" spoofing of any suitable request.
1747 Note that the cache_peer "no-tproxy" option overrides this ACL.
1749 This clause supports fast acl types.
1750 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1755 LOC: Config.accessList.http
1756 DEFAULT_IF_NONE: deny all
1757 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1759 Allowing or Denying access based on defined access lists
1761 To allow or deny a message received on an HTTP, HTTPS, or FTP port:
1762 http_access allow|deny [!]aclname ...
1764 NOTE on default values:
1766 If there are no "access" lines present, the default is to deny
1769 If none of the "access" lines cause a match, the default is the
1770 opposite of the last line in the list. If the last line was
1771 deny, the default is allow. Conversely, if the last line
1772 is allow, the default will be deny. For these reasons, it is a
1773 good idea to have an "deny all" entry at the end of your access
1774 lists to avoid potential confusion.
1776 This clause supports both fast and slow acl types.
1777 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1782 # Recommended minimum Access Permission configuration:
1784 # Deny requests to certain unsafe ports
1785 http_access deny !Safe_ports
1787 # Deny CONNECT to other than secure SSL ports
1788 http_access deny CONNECT !SSL_ports
1790 # Only allow cachemgr access from localhost
1791 http_access allow localhost manager
1792 http_access deny manager
1794 # We strongly recommend the following be uncommented to protect innocent
1795 # web applications running on the proxy server who think the only
1796 # one who can access services on "localhost" is a local user
1797 #http_access deny to_localhost
1800 # INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS
1803 # Example rule allowing access from your local networks.
1804 # Adapt localnet in the ACL section to list your (internal) IP networks
1805 # from where browsing should be allowed
1806 http_access allow localnet
1807 http_access allow localhost
1809 # And finally deny all other access to this proxy
1810 http_access deny all
1814 NAME: adapted_http_access http_access2
1816 LOC: Config.accessList.adapted_http
1818 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1820 Allowing or Denying access based on defined access lists
1822 Essentially identical to http_access, but runs after redirectors
1823 and ICAP/eCAP adaptation. Allowing access control based on their
1826 If not set then only http_access is used.
1829 NAME: http_reply_access
1831 LOC: Config.accessList.reply
1833 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1835 Allow replies to client requests. This is complementary to http_access.
1837 http_reply_access allow|deny [!] aclname ...
1839 NOTE: if there are no access lines present, the default is to allow
1842 If none of the access lines cause a match the opposite of the
1843 last line will apply. Thus it is good practice to end the rules
1844 with an "allow all" or "deny all" entry.
1846 This clause supports both fast and slow acl types.
1847 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1852 LOC: Config.accessList.icp
1854 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1856 Allowing or Denying access to the ICP port based on defined
1859 icp_access allow|deny [!]aclname ...
1861 NOTE: The default if no icp_access lines are present is to
1862 deny all traffic. This default may cause problems with peers
1865 This clause only supports fast acl types.
1866 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1868 # Allow ICP queries from local networks only
1869 #icp_access allow localnet
1870 #icp_access deny all
1876 LOC: Config.accessList.htcp
1878 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1880 Allowing or Denying access to the HTCP port based on defined
1883 htcp_access allow|deny [!]aclname ...
1885 See also htcp_clr_access for details on access control for
1886 cache purge (CLR) HTCP messages.
1888 NOTE: The default if no htcp_access lines are present is to
1889 deny all traffic. This default may cause problems with peers
1890 using the htcp option.
1892 This clause only supports fast acl types.
1893 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1895 # Allow HTCP queries from local networks only
1896 #htcp_access allow localnet
1897 #htcp_access deny all
1900 NAME: htcp_clr_access
1903 LOC: Config.accessList.htcp_clr
1905 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1907 Allowing or Denying access to purge content using HTCP based
1908 on defined access lists.
1909 See htcp_access for details on general HTCP access control.
1911 htcp_clr_access allow|deny [!]aclname ...
1913 This clause only supports fast acl types.
1914 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1916 # Allow HTCP CLR requests from trusted peers
1917 acl htcp_clr_peer src 192.0.2.2 2001:DB8::2
1918 htcp_clr_access allow htcp_clr_peer
1919 htcp_clr_access deny all
1924 LOC: Config.accessList.miss
1926 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1928 Determines whether network access is permitted when satisfying a request.
1931 to force your neighbors to use you as a sibling instead of
1934 acl localclients src 192.0.2.0/24 2001:DB8::a:0/64
1935 miss_access deny !localclients
1936 miss_access allow all
1938 This means only your local clients are allowed to fetch relayed/MISS
1939 replies from the network and all other clients can only fetch cached
1942 The default for this setting allows all clients who passed the
1943 http_access rules to relay via this proxy.
1945 This clause only supports fast acl types.
1946 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1949 NAME: ident_lookup_access
1953 DEFAULT_DOC: Unless rules exist in squid.conf, IDENT is not fetched.
1954 LOC: Ident::TheConfig.identLookup
1956 A list of ACL elements which, if matched, cause an ident
1957 (RFC 931) lookup to be performed for this request. For
1958 example, you might choose to always perform ident lookups
1959 for your main multi-user Unix boxes, but not for your Macs
1960 and PCs. By default, ident lookups are not performed for
1963 To enable ident lookups for specific client addresses, you
1964 can follow this example:
1966 acl ident_aware_hosts src 198.168.1.0/24
1967 ident_lookup_access allow ident_aware_hosts
1968 ident_lookup_access deny all
1970 Only src type ACL checks are fully supported. A srcdomain
1971 ACL might work at times, but it will not always provide
1974 This clause only supports fast acl types.
1975 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1978 NAME: reply_body_max_size
1979 COMMENT: size [acl acl...]
1982 DEFAULT_DOC: No limit is applied.
1983 LOC: Config.ReplyBodySize
1985 This option specifies the maximum size of a reply body. It can be
1986 used to prevent users from downloading very large files, such as
1987 MP3's and movies. When the reply headers are received, the
1988 reply_body_max_size lines are processed, and the first line where
1989 all (if any) listed ACLs are true is used as the maximum body size
1992 This size is checked twice. First when we get the reply headers,
1993 we check the content-length value. If the content length value exists
1994 and is larger than the allowed size, the request is denied and the
1995 user receives an error message that says "the request or reply
1996 is too large." If there is no content-length, and the reply
1997 size exceeds this limit, the client's connection is just closed
1998 and they will receive a partial reply.
2000 WARNING: downstream caches probably can not detect a partial reply
2001 if there is no content-length header, so they will cache
2002 partial responses and give them out as hits. You should NOT
2003 use this option if you have downstream caches.
2005 WARNING: A maximum size smaller than the size of squid's error messages
2006 will cause an infinite loop and crash squid. Ensure that the smallest
2007 non-zero value you use is greater that the maximum header size plus
2008 the size of your largest error page.
2010 If you set this parameter none (the default), there will be
2013 Configuration Format is:
2014 reply_body_max_size SIZE UNITS [acl ...]
2016 reply_body_max_size 10 MB
2020 NAME: on_unsupported_protocol
2021 TYPE: on_unsupported_protocol
2022 LOC: Config.accessList.on_unsupported_protocol
2024 DEFAULT_DOC: Respond with an error message to unidentifiable traffic
2026 Determines Squid behavior when encountering strange requests at the
2027 beginning of an accepted TCP connection or the beginning of a bumped
2028 CONNECT tunnel. Controlling Squid reaction to unexpected traffic is
2029 especially useful in interception environments where Squid is likely
2030 to see connections for unsupported protocols that Squid should either
2031 terminate or tunnel at TCP level.
2033 on_unsupported_protocol <action> [!]acl ...
2035 The first matching action wins. Only fast ACLs are supported.
2037 Supported actions are:
2039 tunnel: Establish a TCP connection with the intended server and
2040 blindly shovel TCP packets between the client and server.
2042 respond: Respond with an error message, using the transfer protocol
2043 for the Squid port that received the request (e.g., HTTP
2044 for connections intercepted at the http_port). This is the
2047 Squid expects the following traffic patterns:
2049 http_port: a plain HTTP request
2050 https_port: SSL/TLS handshake followed by an [encrypted] HTTP request
2051 ftp_port: a plain FTP command (no on_unsupported_protocol support yet!)
2052 CONNECT tunnel on http_port: same as https_port
2053 CONNECT tunnel on https_port: same as https_port
2055 Currently, this directive has effect on intercepted connections and
2056 bumped tunnels only. Other cases are not supported because Squid
2057 cannot know the intended destination of other traffic.
2060 # define what Squid errors indicate receiving non-HTTP traffic:
2061 acl foreignProtocol squid_error ERR_PROTOCOL_UNKNOWN ERR_TOO_BIG
2062 # define what Squid errors indicate receiving nothing:
2063 acl serverTalksFirstProtocol squid_error ERR_REQUEST_START_TIMEOUT
2064 # tunnel everything that does not look like HTTP:
2065 on_unsupported_protocol tunnel foreignProtocol
2066 # tunnel if we think the client waits for the server to talk first:
2067 on_unsupported_protocol tunnel serverTalksFirstProtocol
2068 # in all other error cases, just send an HTTP "error page" response:
2069 on_unsupported_protocol respond all
2071 See also: squid_error ACL
2077 LOC: Auth::TheConfig.schemeAccess
2079 DEFAULT_DOC: use all auth_param schemes in their configuration order
2081 Use this directive to customize authentication schemes presence and
2082 order in Squid's Unauthorized and Authentication Required responses.
2084 auth_schemes scheme1,scheme2,... [!]aclname ...
2086 where schemeN is the name of one of the authentication schemes
2087 configured using auth_param directives. At least one scheme name is
2088 required. Multiple scheme names are separated by commas. Either
2089 avoid whitespace or quote the entire schemes list.
2091 A special "ALL" scheme name expands to all auth_param-configured
2092 schemes in their configuration order. This directive cannot be used
2093 to configure Squid to offer no authentication schemes at all.
2095 The first matching auth_schemes rule determines the schemes order
2096 for the current Authentication Required transaction. Note that the
2097 future response is not yet available during auth_schemes evaluation.
2099 If this directive is not used or none of its rules match, then Squid
2100 responds with all configured authentication schemes in the order of
2101 auth_param directives in the configuration file.
2103 This directive does not determine when authentication is used or
2104 how each authentication scheme authenticates clients.
2106 The following example sends basic and negotiate authentication
2107 schemes, in that order, when requesting authentication of HTTP
2108 requests matching the isIE ACL (not shown) while sending all
2109 auth_param schemes in their configuration order to other clients:
2111 auth_schemes basic,negotiate isIE
2112 auth_schemes ALL all # explicit default
2114 This directive supports fast ACLs only.
2116 See also: auth_param.
2121 -----------------------------------------------------------------------------
2124 NAME: http_port ascii_port
2129 Usage: port [mode] [options]
2130 hostname:port [mode] [options]
2131 1.2.3.4:port [mode] [options]
2133 The socket addresses where Squid will listen for HTTP client
2134 requests. You may specify multiple socket addresses.
2135 There are three forms: port alone, hostname with port, and
2136 IP address with port. If you specify a hostname or IP
2137 address, Squid binds the socket to that specific
2138 address. Most likely, you do not need to bind to a specific
2139 address, so you can use the port number alone.
2141 If you are running Squid in accelerator mode, you
2142 probably want to listen on port 80 also, or instead.
2144 The -a command line option may be used to specify additional
2145 port(s) where Squid listens for proxy request. Such ports will
2146 be plain proxy ports with no options.
2148 You may specify multiple socket addresses on multiple lines.
2152 intercept Support for IP-Layer NAT interception delivering
2153 traffic to this Squid port.
2154 NP: disables authentication on the port.
2156 tproxy Support Linux TPROXY (or BSD divert-to) with spoofing
2157 of outgoing connections using the client IP address.
2158 NP: disables authentication on the port.
2160 accel Accelerator / reverse proxy mode
2162 ssl-bump For each CONNECT request allowed by ssl_bump ACLs,
2163 establish secure connection with the client and with
2164 the server, decrypt HTTPS messages as they pass through
2165 Squid, and treat them as unencrypted HTTP messages,
2166 becoming the man-in-the-middle.
2168 The ssl_bump option is required to fully enable
2169 bumping of CONNECT requests.
2171 Omitting the mode flag causes default forward proxy mode to be used.
2174 Accelerator Mode Options:
2176 defaultsite=domainname
2177 What to use for the Host: header if it is not present
2178 in a request. Determines what site (not origin server)
2179 accelerators should consider the default.
2181 no-vhost Disable using HTTP/1.1 Host header for virtual domain support.
2183 protocol= Protocol to reconstruct accelerated and intercepted
2184 requests with. Defaults to HTTP/1.1 for http_port and
2185 HTTPS/1.1 for https_port.
2186 When an unsupported value is configured Squid will
2187 produce a FATAL error.
2188 Values: HTTP or HTTP/1.1, HTTPS or HTTPS/1.1
2190 vport Virtual host port support. Using the http_port number
2191 instead of the port passed on Host: headers.
2193 vport=NN Virtual host port support. Using the specified port
2194 number instead of the port passed on Host: headers.
2197 Act as if this Squid is the origin server.
2198 This currently means generate new Date: and Expires:
2199 headers on HIT instead of adding Age:.
2201 ignore-cc Ignore request Cache-Control headers.
2203 WARNING: This option violates HTTP specifications if
2204 used in non-accelerator setups.
2206 allow-direct Allow direct forwarding in accelerator mode. Normally
2207 accelerated requests are denied direct forwarding as if
2208 never_direct was used.
2210 WARNING: this option opens accelerator mode to security
2211 vulnerabilities usually only affecting in interception
2212 mode. Make sure to protect forwarding with suitable
2213 http_access rules when using this.
2216 SSL Bump Mode Options:
2217 In addition to these options ssl-bump requires TLS/SSL options.
2219 generate-host-certificates[=<on|off>]
2220 Dynamically create SSL server certificates for the
2221 destination hosts of bumped CONNECT requests.When
2222 enabled, the cert and key options are used to sign
2223 generated certificates. Otherwise generated
2224 certificate will be selfsigned.
2225 If there is a CA certificate lifetime of the generated
2226 certificate equals lifetime of the CA certificate. If
2227 generated certificate is selfsigned lifetime is three
2229 This option is enabled by default when ssl-bump is used.
2230 See the ssl-bump option above for more information.
2232 dynamic_cert_mem_cache_size=SIZE
2233 Approximate total RAM size spent on cached generated
2234 certificates. If set to zero, caching is disabled. The
2235 default value is 4MB.
2239 tls-cert= Path to file containing an X.509 certificate (PEM format)
2240 to be used in the TLS handshake ServerHello.
2242 If this certificate is constrained by KeyUsage TLS
2243 feature it must allow HTTP server usage, along with
2244 any additional restrictions imposed by your choice
2245 of options= settings.
2247 When OpenSSL is used this file may also contain a
2248 chain of intermediate CA certificates to send in the
2251 When GnuTLS is used this option (and any paired
2252 tls-key= option) may be repeated to load multiple
2253 certificates for different domains.
2255 Also, when generate-host-certificates=on is configured
2256 the first tls-cert= option must be a CA certificate
2257 capable of signing the automatically generated
2260 tls-key= Path to a file containing private key file (PEM format)
2261 for the previous tls-cert= option.
2263 If tls-key= is not specified tls-cert= is assumed to
2264 reference a PEM file containing both the certificate
2267 cipher= Colon separated list of supported ciphers.
2268 NOTE: some ciphers such as EDH ciphers depend on
2269 additional settings. If those settings are
2270 omitted the ciphers may be silently ignored
2271 by the OpenSSL library.
2273 options= Various SSL implementation options. The most important
2276 NO_SSLv3 Disallow the use of SSLv3
2278 NO_TLSv1 Disallow the use of TLSv1.0
2280 NO_TLSv1_1 Disallow the use of TLSv1.1
2282 NO_TLSv1_2 Disallow the use of TLSv1.2
2285 Always create a new key when using
2286 temporary/ephemeral DH key exchanges
2289 Enable ephemeral ECDH key exchange.
2290 The adopted curve should be specified
2291 using the tls-dh option.
2294 Disable use of RFC5077 session tickets.
2295 Some servers may have problems
2296 understanding the TLS extension due
2297 to ambiguous specification in RFC4507.
2299 ALL Enable various bug workarounds
2300 suggested as "harmless" by OpenSSL
2301 Be warned that this reduces SSL/TLS
2302 strength to some attacks.
2304 See the OpenSSL SSL_CTX_set_options documentation for a
2307 clientca= File containing the list of CAs to use when
2308 requesting a client certificate.
2310 tls-cafile= PEM file containing CA certificates to use when verifying
2311 client certificates. If not configured clientca will be
2312 used. May be repeated to load multiple files.
2314 capath= Directory containing additional CA certificates
2315 and CRL lists to use when verifying client certificates.
2316 Requires OpenSSL or LibreSSL.
2318 crlfile= File of additional CRL lists to use when verifying
2319 the client certificate, in addition to CRLs stored in
2320 the capath. Implies VERIFY_CRL flag below.
2323 File containing DH parameters for temporary/ephemeral DH key
2324 exchanges, optionally prefixed by a curve for ephemeral ECDH
2326 See OpenSSL documentation for details on how to create the
2327 DH parameter file. Supported curves for ECDH can be listed
2328 using the "openssl ecparam -list_curves" command.
2329 WARNING: EDH and EECDH ciphers will be silently disabled if
2330 this option is not set.
2332 sslflags= Various flags modifying the use of SSL:
2334 Don't request client certificates
2335 immediately, but wait until acl processing
2336 requires a certificate (not yet implemented).
2338 Don't allow for session reuse. Each connection
2339 will result in a new SSL session.
2341 Verify CRL lists when accepting client
2344 Verify CRL lists for all certificates in the
2345 client certificate chain.
2347 tls-default-ca[=off]
2348 Whether to use the system Trusted CAs. Default is OFF.
2350 tls-no-npn Do not use the TLS NPN extension to advertise HTTP/1.1.
2352 sslcontext= SSL session ID context identifier.
2356 connection-auth[=on|off]
2357 use connection-auth=off to tell Squid to prevent
2358 forwarding Microsoft connection oriented authentication
2359 (NTLM, Negotiate and Kerberos)
2361 disable-pmtu-discovery=
2362 Control Path-MTU discovery usage:
2363 off lets OS decide on what to do (default).
2364 transparent disable PMTU discovery when transparent
2366 always disable always PMTU discovery.
2368 In many setups of transparently intercepting proxies
2369 Path-MTU discovery can not work on traffic towards the
2370 clients. This is the case when the intercepting device
2371 does not fully track connections and fails to forward
2372 ICMP must fragment messages to the cache server. If you
2373 have such setup and experience that certain clients
2374 sporadically hang or never complete requests set
2375 disable-pmtu-discovery option to 'transparent'.
2377 name= Specifies a internal name for the port. Defaults to
2378 the port specification (port or addr:port)
2380 tcpkeepalive[=idle,interval,timeout]
2381 Enable TCP keepalive probes of idle connections.
2382 In seconds; idle is the initial time before TCP starts
2383 probing the connection, interval how often to probe, and
2384 timeout the time before giving up.
2386 require-proxy-header
2387 Require PROXY protocol version 1 or 2 connections.
2388 The proxy_protocol_access is required to whitelist
2389 downstream proxies which can be trusted.
2391 If you run Squid on a dual-homed machine with an internal
2392 and an external interface we recommend you to specify the
2393 internal address:port in http_port. This way Squid will only be
2394 visible on the internal address.
2398 # Squid normally listens to port 3128
2399 http_port @DEFAULT_HTTP_PORT@
2404 IFDEF: USE_GNUTLS||USE_OPENSSL
2409 Usage: [ip:]port [mode] tls-cert=certificate.pem [options]
2411 The socket address where Squid will listen for client requests made
2412 over TLS or SSL connections. Commonly referred to as HTTPS.
2414 This is most useful for situations where you are running squid in
2415 accelerator mode and you want to do the TLS work at the accelerator
2418 You may specify multiple socket addresses on multiple lines,
2419 each with their own certificate and/or options.
2421 The tls-cert= option is mandatory on HTTPS ports.
2423 See http_port for a list of modes and options.
2431 Enables Native FTP proxy by specifying the socket address where Squid
2432 listens for FTP client requests. See http_port directive for various
2433 ways to specify the listening address and mode.
2435 Usage: ftp_port address [mode] [options]
2437 WARNING: This is a new, experimental, complex feature that has seen
2438 limited production exposure. Some Squid modules (e.g., caching) do not
2439 currently work with native FTP proxying, and many features have not
2440 even been tested for compatibility. Test well before deploying!
2442 Native FTP proxying differs substantially from proxying HTTP requests
2443 with ftp:// URIs because Squid works as an FTP server and receives
2444 actual FTP commands (rather than HTTP requests with FTP URLs).
2446 Native FTP commands accepted at ftp_port are internally converted or
2447 wrapped into HTTP-like messages. The same happens to Native FTP
2448 responses received from FTP origin servers. Those HTTP-like messages
2449 are shoveled through regular access control and adaptation layers
2450 between the FTP client and the FTP origin server. This allows Squid to
2451 examine, adapt, block, and log FTP exchanges. Squid reuses most HTTP
2452 mechanisms when shoveling wrapped FTP messages. For example,
2453 http_access and adaptation_access directives are used.
2457 intercept Same as http_port intercept. The FTP origin address is
2458 determined based on the intended destination of the
2459 intercepted connection.
2461 tproxy Support Linux TPROXY for spoofing outgoing
2462 connections using the client IP address.
2463 NP: disables authentication and maybe IPv6 on the port.
2465 By default (i.e., without an explicit mode option), Squid extracts the
2466 FTP origin address from the login@origin parameter of the FTP USER
2467 command. Many popular FTP clients support such native FTP proxying.
2471 name=token Specifies an internal name for the port. Defaults to
2472 the port address. Usable with myportname ACL.
2475 Enables tracking of FTP directories by injecting extra
2476 PWD commands and adjusting Request-URI (in wrapping
2477 HTTP requests) to reflect the current FTP server
2478 directory. Tracking is disabled by default.
2480 protocol=FTP Protocol to reconstruct accelerated and intercepted
2481 requests with. Defaults to FTP. No other accepted
2482 values have been tested with. An unsupported value
2483 results in a FATAL error. Accepted values are FTP,
2484 HTTP (or HTTP/1.1), and HTTPS (or HTTPS/1.1).
2486 Other http_port modes and options that are not specific to HTTP and
2487 HTTPS may also work.
2490 NAME: tcp_outgoing_tos tcp_outgoing_ds tcp_outgoing_dscp
2493 LOC: Ip::Qos::TheConfig.tosToServer
2495 Allows you to select a TOS/Diffserv value for packets outgoing
2496 on the server side, based on an ACL.
2498 tcp_outgoing_tos ds-field [!]aclname ...
2500 Example where normal_service_net uses the TOS value 0x00
2501 and good_service_net uses 0x20
2503 acl normal_service_net src 10.0.0.0/24
2504 acl good_service_net src 10.0.1.0/24
2505 tcp_outgoing_tos 0x00 normal_service_net
2506 tcp_outgoing_tos 0x20 good_service_net
2508 TOS/DSCP values really only have local significance - so you should
2509 know what you're specifying. For more information, see RFC2474,
2510 RFC2475, and RFC3260.
2512 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
2513 "default" to use whatever default your host has.
2514 Note that only multiples of 4 are usable as the two rightmost bits have
2515 been redefined for use by ECN (RFC 3168 section 23.1).
2516 The squid parser will enforce this by masking away the ECN bits.
2518 Processing proceeds in the order specified, and stops at first fully
2521 Only fast ACLs are supported.
2524 NAME: clientside_tos
2527 LOC: Ip::Qos::TheConfig.tosToClient
2529 Allows you to select a TOS/DSCP value for packets being transmitted
2530 on the client-side, based on an ACL.
2532 clientside_tos ds-field [!]aclname ...
2534 Example where normal_service_net uses the TOS value 0x00
2535 and good_service_net uses 0x20
2537 acl normal_service_net src 10.0.0.0/24
2538 acl good_service_net src 10.0.1.0/24
2539 clientside_tos 0x00 normal_service_net
2540 clientside_tos 0x20 good_service_net
2542 Note: This feature is incompatible with qos_flows. Any TOS values set here
2543 will be overwritten by TOS values in qos_flows.
2545 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
2546 "default" to use whatever default your host has.
2547 Note that only multiples of 4 are usable as the two rightmost bits have
2548 been redefined for use by ECN (RFC 3168 section 23.1).
2549 The squid parser will enforce this by masking away the ECN bits.
2551 This clause only supports fast acl types.
2552 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2555 NAME: tcp_outgoing_mark
2557 IFDEF: SO_MARK&&USE_LIBCAP
2559 LOC: Ip::Qos::TheConfig.nfmarkToServer
2561 Allows you to apply a Netfilter mark value to outgoing packets
2562 on the server side, based on an ACL.
2564 tcp_outgoing_mark mark-value [!]aclname ...
2566 Example where normal_service_net uses the mark value 0x00
2567 and good_service_net uses 0x20
2569 acl normal_service_net src 10.0.0.0/24
2570 acl good_service_net src 10.0.1.0/24
2571 tcp_outgoing_mark 0x00 normal_service_net
2572 tcp_outgoing_mark 0x20 good_service_net
2574 Only fast ACLs are supported.
2577 NAME: mark_client_packet clientside_mark
2579 IFDEF: SO_MARK&&USE_LIBCAP
2581 LOC: Ip::Qos::TheConfig.nfmarkToClient
2583 Allows you to apply a Netfilter MARK value to packets being transmitted
2584 on the client-side, based on an ACL.
2586 mark_client_packet mark-value [!]aclname ...
2588 Example where normal_service_net uses the MARK value 0x00
2589 and good_service_net uses 0x20
2591 acl normal_service_net src 10.0.0.0/24
2592 acl good_service_net src 10.0.1.0/24
2593 mark_client_packet 0x00 normal_service_net
2594 mark_client_packet 0x20 good_service_net
2596 Note: This feature is incompatible with qos_flows. Any mark values set here
2597 will be overwritten by mark values in qos_flows.
2599 This clause only supports fast acl types.
2600 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2603 NAME: mark_client_connection
2605 IFDEF: SO_MARK&&USE_LIBCAP
2607 LOC: Ip::Qos::TheConfig.nfConnmarkToClient
2609 Allows you to apply a Netfilter CONNMARK value to a connection
2610 on the client-side, based on an ACL.
2612 mark_client_connection mark-value[/mask] [!]aclname ...
2614 The mark-value and mask are unsigned integers (hex, octal, or decimal).
2615 The mask may be used to preserve marking previously set by other agents
2618 A matching rule replaces the CONNMARK value. If a mask is also
2619 specified, then the masked bits of the original value are zeroed, and
2620 the configured mark-value is ORed with that adjusted value.
2621 For example, applying a mark-value 0xAB/0xF to 0x5F CONNMARK, results
2622 in a 0xFB marking (rather than a 0xAB or 0x5B).
2624 This directive semantics is similar to iptables --set-mark rather than
2625 --set-xmark functionality.
2627 The directive does not interfere with qos_flows (which uses packet MARKs,
2630 Example where squid marks intercepted FTP connections:
2632 acl proto_ftp proto FTP
2633 mark_client_connection 0x200/0xff00 proto_ftp
2635 This clause only supports fast acl types.
2636 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2643 LOC: Ip::Qos::TheConfig
2645 Allows you to select a TOS/DSCP value to mark outgoing
2646 connections to the client, based on where the reply was sourced.
2647 For platforms using netfilter, allows you to set a netfilter mark
2648 value instead of, or in addition to, a TOS value.
2650 By default this functionality is disabled. To enable it with the default
2651 settings simply use "qos_flows mark" or "qos_flows tos". Default
2652 settings will result in the netfilter mark or TOS value being copied
2653 from the upstream connection to the client. Note that it is the connection
2654 CONNMARK value not the packet MARK value that is copied.
2656 It is not currently possible to copy the mark or TOS value from the
2657 client to the upstream connection request.
2659 TOS values really only have local significance - so you should
2660 know what you're specifying. For more information, see RFC2474,
2661 RFC2475, and RFC3260.
2663 The TOS/DSCP byte must be exactly that - a octet value 0 - 255.
2664 Note that only multiples of 4 are usable as the two rightmost bits have
2665 been redefined for use by ECN (RFC 3168 section 23.1).
2666 The squid parser will enforce this by masking away the ECN bits.
2668 Mark values can be any unsigned 32-bit integer value.
2670 This setting is configured by setting the following values:
2672 tos|mark Whether to set TOS or netfilter mark values
2674 local-hit=0xFF Value to mark local cache hits.
2676 sibling-hit=0xFF Value to mark hits from sibling peers.
2678 parent-hit=0xFF Value to mark hits from parent peers.
2680 miss=0xFF[/mask] Value to mark cache misses. Takes precedence
2681 over the preserve-miss feature (see below), unless
2682 mask is specified, in which case only the bits
2683 specified in the mask are written.
2685 The TOS variant of the following features are only possible on Linux
2686 and require your kernel to be patched with the TOS preserving ZPH
2687 patch, available from http://zph.bratcheda.org
2688 No patch is needed to preserve the netfilter mark, which will work
2689 with all variants of netfilter.
2691 disable-preserve-miss
2692 This option disables the preservation of the TOS or netfilter
2693 mark. By default, the existing TOS or netfilter mark value of
2694 the response coming from the remote server will be retained
2695 and masked with miss-mark.
2696 NOTE: in the case of a netfilter mark, the mark must be set on
2697 the connection (using the CONNMARK target) not on the packet
2701 Allows you to mask certain bits in the TOS or mark value
2702 received from the remote server, before copying the value to
2703 the TOS sent towards clients.
2704 Default for tos: 0xFF (TOS from server is not changed).
2705 Default for mark: 0xFFFFFFFF (mark from server is not changed).
2707 All of these features require the --enable-zph-qos compilation flag
2708 (enabled by default). Netfilter marking also requires the
2709 libnetfilter_conntrack libraries (--with-netfilter-conntrack) and
2710 libcap 2.09+ (--with-libcap).
2714 NAME: tcp_outgoing_address
2717 DEFAULT_DOC: Address selection is performed by the operating system.
2718 LOC: Config.accessList.outgoing_address
2720 Allows you to map requests to different outgoing IP addresses
2721 based on the username or source address of the user making
2724 tcp_outgoing_address ipaddr [[!]aclname] ...
2727 Forwarding clients with dedicated IPs for certain subnets.
2729 acl normal_service_net src 10.0.0.0/24
2730 acl good_service_net src 10.0.2.0/24
2732 tcp_outgoing_address 2001:db8::c001 good_service_net
2733 tcp_outgoing_address 10.1.0.2 good_service_net
2735 tcp_outgoing_address 2001:db8::beef normal_service_net
2736 tcp_outgoing_address 10.1.0.1 normal_service_net
2738 tcp_outgoing_address 2001:db8::1
2739 tcp_outgoing_address 10.1.0.3
2741 Processing proceeds in the order specified, and stops at first fully
2744 Squid will add an implicit IP version test to each line.
2745 Requests going to IPv4 websites will use the outgoing 10.1.0.* addresses.
2746 Requests going to IPv6 websites will use the outgoing 2001:db8:* addresses.
2749 NOTE: The use of this directive using client dependent ACLs is
2750 incompatible with the use of server side persistent connections. To
2751 ensure correct results it is best to set server_persistent_connections
2752 to off when using this directive in such configurations.
2754 NOTE: The use of this directive to set a local IP on outgoing TCP links
2755 is incompatible with using TPROXY to set client IP out outbound TCP links.
2756 When needing to contact peers use the no-tproxy cache_peer option and the
2757 client_dst_passthru directive re-enable normal forwarding such as this.
2759 This clause only supports fast acl types.
2760 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2763 NAME: host_verify_strict
2766 LOC: Config.onoff.hostStrictVerify
2768 Regardless of this option setting, when dealing with intercepted
2769 traffic, Squid always verifies that the destination IP address matches
2770 the Host header domain or IP (called 'authority form URL').
2772 This enforcement is performed to satisfy a MUST-level requirement in
2773 RFC 2616 section 14.23: "The Host field value MUST represent the naming
2774 authority of the origin server or gateway given by the original URL".
2777 Squid always responds with an HTTP 409 (Conflict) error
2778 page and logs a security warning if there is no match.
2780 Squid verifies that the destination IP address matches
2781 the Host header for forward-proxy and reverse-proxy traffic
2782 as well. For those traffic types, Squid also enables the
2783 following checks, comparing the corresponding Host header
2784 and Request-URI components:
2786 * The host names (domain or IP) must be identical,
2787 but valueless or missing Host header disables all checks.
2788 For the two host names to match, both must be either IP
2791 * Port numbers must be identical, but if a port is missing
2792 the scheme-default port is assumed.
2795 When set to OFF (the default):
2796 Squid allows suspicious requests to continue but logs a
2797 security warning and blocks caching of the response.
2799 * Forward-proxy traffic is not checked at all.
2801 * Reverse-proxy traffic is not checked at all.
2803 * Intercepted traffic which passes verification is handled
2804 according to client_dst_passthru.
2806 * Intercepted requests which fail verification are sent
2807 to the client original destination instead of DIRECT.
2808 This overrides 'client_dst_passthru off'.
2810 For now suspicious intercepted CONNECT requests are always
2811 responded to with an HTTP 409 (Conflict) error page.
2816 As described in CVE-2009-0801 when the Host: header alone is used
2817 to determine the destination of a request it becomes trivial for
2818 malicious scripts on remote websites to bypass browser same-origin
2819 security policy and sandboxing protections.
2821 The cause of this is that such applets are allowed to perform their
2822 own HTTP stack, in which case the same-origin policy of the browser
2823 sandbox only verifies that the applet tries to contact the same IP
2824 as from where it was loaded at the IP level. The Host: header may
2825 be different from the connected IP and approved origin.
2829 NAME: client_dst_passthru
2832 LOC: Config.onoff.client_dst_passthru
2834 With NAT or TPROXY intercepted traffic Squid may pass the request
2835 directly to the original client destination IP or seek a faster
2836 source using the HTTP Host header.
2838 Using Host to locate alternative servers can provide faster
2839 connectivity with a range of failure recovery options.
2840 But can also lead to connectivity trouble when the client and
2841 server are attempting stateful interactions unaware of the proxy.
2843 This option (on by default) prevents alternative DNS entries being
2844 located to send intercepted traffic DIRECT to an origin server.
2845 The clients original destination IP and port will be used instead.
2847 Regardless of this option setting, when dealing with intercepted
2848 traffic Squid will verify the Host: header and any traffic which
2849 fails Host verification will be treated as if this option were ON.
2851 see host_verify_strict for details on the verification process.
2856 -----------------------------------------------------------------------------
2859 NAME: tls_outgoing_options
2860 IFDEF: USE_GNUTLS||USE_OPENSSL
2861 TYPE: securePeerOptions
2862 DEFAULT: min-version=1.0
2863 LOC: Security::ProxyOutgoingConfig
2865 disable Do not support https:// URLs.
2867 cert=/path/to/client/certificate
2868 A client X.509 certificate to use when connecting.
2870 key=/path/to/client/private_key
2871 The private key corresponding to the cert= above.
2873 If key= is not specified cert= is assumed to
2874 reference a PEM file containing both the certificate
2877 cipher=... The list of valid TLS ciphers to use.
2880 The minimum TLS protocol version to permit.
2881 To control SSLv3 use the options= parameter.
2882 Supported Values: 1.0 (default), 1.1, 1.2
2884 options=... Specify various TLS/SSL implementation options.
2886 OpenSSL options most important are:
2888 NO_SSLv3 Disallow the use of SSLv3
2891 Always create a new key when using
2892 temporary/ephemeral DH key exchanges
2895 Disable use of RFC5077 session tickets.
2896 Some servers may have problems
2897 understanding the TLS extension due
2898 to ambiguous specification in RFC4507.
2900 ALL Enable various bug workarounds
2901 suggested as "harmless" by OpenSSL
2902 Be warned that this reduces SSL/TLS
2903 strength to some attacks.
2905 See the OpenSSL SSL_CTX_set_options documentation
2906 for a more complete list.
2908 GnuTLS options most important are:
2911 Disable use of RFC5077 session tickets.
2912 Some servers may have problems
2913 understanding the TLS extension due
2914 to ambiguous specification in RFC4507.
2916 See the GnuTLS Priority Strings documentation
2917 for a more complete list.
2918 http://www.gnutls.org/manual/gnutls.html#Priority-Strings
2921 cafile= PEM file containing CA certificates to use when verifying
2922 the peer certificate. May be repeated to load multiple files.
2924 capath= A directory containing additional CA certificates to
2925 use when verifying the peer certificate.
2926 Requires OpenSSL or LibreSSL.
2928 crlfile=... A certificate revocation list file to use when
2929 verifying the peer certificate.
2931 flags=... Specify various flags modifying the TLS implementation:
2934 Accept certificates even if they fail to
2937 Don't verify the peer certificate
2938 matches the server name
2941 Whether to use the system Trusted CAs. Default is ON.
2943 domain= The peer name as advertised in its certificate.
2944 Used for verifying the correctness of the received peer
2945 certificate. If not specified the peer hostname will be
2951 -----------------------------------------------------------------------------
2954 NAME: ssl_unclean_shutdown
2958 LOC: Config.SSL.unclean_shutdown
2960 Some browsers (especially MSIE) bugs out on SSL shutdown
2967 LOC: Config.SSL.ssl_engine
2970 The OpenSSL engine to use. You will need to set this if you
2971 would like to use hardware SSL acceleration for example.
2974 NAME: sslproxy_session_ttl
2977 LOC: Config.SSL.session_ttl
2980 Sets the timeout value for SSL sessions
2983 NAME: sslproxy_session_cache_size
2986 LOC: Config.SSL.sessionCacheSize
2989 Sets the cache size to use for ssl session
2992 NAME: sslproxy_foreign_intermediate_certs
2995 LOC: Config.ssl_client.foreignIntermediateCertsPath
2998 Many origin servers fail to send their full server certificate
2999 chain for verification, assuming the client already has or can
3000 easily locate any missing intermediate certificates.
3002 Squid uses the certificates from the specified file to fill in
3003 these missing chains when trying to validate origin server
3006 The file is expected to contain zero or more PEM-encoded
3007 intermediate certificates. These certificates are not treated
3008 as trusted root certificates, and any self-signed certificate in
3009 this file will be ignored.
3012 NAME: sslproxy_cert_sign_hash
3015 LOC: Config.SSL.certSignHash
3018 Sets the hashing algorithm to use when signing generated certificates.
3019 Valid algorithm names depend on the OpenSSL library used. The following
3020 names are usually available: sha1, sha256, sha512, and md5. Please see
3021 your OpenSSL library manual for the available hashes. By default, Squids
3022 that support this option use sha256 hashes.
3024 Squid does not forcefully purge cached certificates that were generated
3025 with an algorithm other than the currently configured one. They remain
3026 in the cache, subject to the regular cache eviction policy, and become
3027 useful if the algorithm changes again.
3032 TYPE: sslproxy_ssl_bump
3033 LOC: Config.accessList.ssl_bump
3034 DEFAULT_DOC: Become a TCP tunnel without decrypting proxied traffic.
3037 This option is consulted when a CONNECT request is received on
3038 an http_port (or a new connection is intercepted at an
3039 https_port), provided that port was configured with an ssl-bump
3040 flag. The subsequent data on the connection is either treated as
3041 HTTPS and decrypted OR tunneled at TCP level without decryption,
3042 depending on the first matching bumping "action".
3044 ssl_bump <action> [!]acl ...
3046 The following bumping actions are currently supported:
3049 Become a TCP tunnel without decrypting proxied traffic.
3050 This is the default action.
3053 When used on step SslBump1, establishes a secure connection
3054 with the client first, then connect to the server.
3055 When used on step SslBump2 or SslBump3, establishes a secure
3056 connection with the server and, using a mimicked server
3057 certificate, with the client.
3060 Receive client (step SslBump1) or server (step SslBump2)
3061 certificate while preserving the possibility of splicing the
3062 connection. Peeking at the server certificate (during step 2)
3063 usually precludes bumping of the connection at step 3.
3066 Receive client (step SslBump1) or server (step SslBump2)
3067 certificate while preserving the possibility of bumping the
3068 connection. Staring at the server certificate (during step 2)
3069 usually precludes splicing of the connection at step 3.
3072 Close client and server connections.
3074 Backward compatibility actions available at step SslBump1:
3077 Bump the connection. Establish a secure connection with the
3078 client first, then connect to the server. This old mode does
3079 not allow Squid to mimic server SSL certificate and does not
3080 work with intercepted SSL connections.
3083 Bump the connection. Establish a secure connection with the
3084 server first, then establish a secure connection with the
3085 client, using a mimicked server certificate. Works with both
3086 CONNECT requests and intercepted SSL connections, but does
3087 not allow to make decisions based on SSL handshake info.
3090 Decide whether to bump or splice the connection based on
3091 client-to-squid and server-to-squid SSL hello messages.
3095 Same as the "splice" action.
3097 All ssl_bump rules are evaluated at each of the supported bumping
3098 steps. Rules with actions that are impossible at the current step are
3099 ignored. The first matching ssl_bump action wins and is applied at the
3100 end of the current step. If no rules match, the splice action is used.
3101 See the at_step ACL for a list of the supported SslBump steps.
3103 This clause supports both fast and slow acl types.
3104 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
3106 See also: http_port ssl-bump, https_port ssl-bump, and acl at_step.
3109 # Example: Bump all TLS connections except those originating from
3110 # localhost or those going to example.com.
3112 acl broken_sites ssl::server_name .example.com
3113 ssl_bump splice localhost
3114 ssl_bump splice broken_sites
3118 NAME: sslproxy_cert_error
3121 DEFAULT_DOC: Server certificate errors terminate the transaction.
3122 LOC: Config.ssl_client.cert_error
3125 Use this ACL to bypass server certificate validation errors.
3127 For example, the following lines will bypass all validation errors
3128 when talking to servers for example.com. All other
3129 validation errors will result in ERR_SECURE_CONNECT_FAIL error.
3131 acl BrokenButTrustedServers dstdomain example.com
3132 sslproxy_cert_error allow BrokenButTrustedServers
3133 sslproxy_cert_error deny all
3135 This clause only supports fast acl types.
3136 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
3137 Using slow acl types may result in server crashes
3139 Without this option, all server certificate validation errors
3140 terminate the transaction to protect Squid and the client.
3142 SQUID_X509_V_ERR_INFINITE_VALIDATION error cannot be bypassed
3143 but should not happen unless your OpenSSL library is buggy.
3146 Bypassing validation errors is dangerous because an
3147 error usually implies that the server cannot be trusted
3148 and the connection may be insecure.
3150 See also: sslproxy_flags and DONT_VERIFY_PEER.
3153 NAME: sslproxy_cert_sign
3156 POSTSCRIPTUM: signUntrusted ssl::certUntrusted
3157 POSTSCRIPTUM: signSelf ssl::certSelfSigned
3158 POSTSCRIPTUM: signTrusted all
3159 TYPE: sslproxy_cert_sign
3160 LOC: Config.ssl_client.cert_sign
3163 sslproxy_cert_sign <signing algorithm> acl ...
3165 The following certificate signing algorithms are supported:
3168 Sign using the configured CA certificate which is usually
3169 placed in and trusted by end-user browsers. This is the
3170 default for trusted origin server certificates.
3173 Sign to guarantee an X509_V_ERR_CERT_UNTRUSTED browser error.
3174 This is the default for untrusted origin server certificates
3175 that are not self-signed (see ssl::certUntrusted).
3178 Sign using a self-signed certificate with the right CN to
3179 generate a X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT error in the
3180 browser. This is the default for self-signed origin server
3181 certificates (see ssl::certSelfSigned).
3183 This clause only supports fast acl types.
3185 When sslproxy_cert_sign acl(s) match, Squid uses the corresponding
3186 signing algorithm to generate the certificate and ignores all
3187 subsequent sslproxy_cert_sign options (the first match wins). If no
3188 acl(s) match, the default signing algorithm is determined by errors
3189 detected when obtaining and validating the origin server certificate.
3191 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
3192 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
3193 CONNECT request that carries a domain name. In all other cases (CONNECT
3194 to an IP address or an intercepted SSL connection), Squid cannot detect
3195 the domain mismatch at certificate generation time when
3196 bump-server-first is used.
3199 NAME: sslproxy_cert_adapt
3202 TYPE: sslproxy_cert_adapt
3203 LOC: Config.ssl_client.cert_adapt
3206 sslproxy_cert_adapt <adaptation algorithm> acl ...
3208 The following certificate adaptation algorithms are supported:
3211 Sets the "Not After" property to the "Not After" property of
3212 the CA certificate used to sign generated certificates.
3215 Sets the "Not Before" property to the "Not Before" property of
3216 the CA certificate used to sign generated certificates.
3218 setCommonName or setCommonName{CN}
3219 Sets Subject.CN property to the host name specified as a
3220 CN parameter or, if no explicit CN parameter was specified,
3221 extracted from the CONNECT request. It is a misconfiguration
3222 to use setCommonName without an explicit parameter for
3223 intercepted or tproxied SSL connections.
3225 This clause only supports fast acl types.
3227 Squid first groups sslproxy_cert_adapt options by adaptation algorithm.
3228 Within a group, when sslproxy_cert_adapt acl(s) match, Squid uses the
3229 corresponding adaptation algorithm to generate the certificate and
3230 ignores all subsequent sslproxy_cert_adapt options in that algorithm's
3231 group (i.e., the first match wins within each algorithm group). If no
3232 acl(s) match, the default mimicking action takes place.
3234 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
3235 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
3236 CONNECT request that carries a domain name. In all other cases (CONNECT
3237 to an IP address or an intercepted SSL connection), Squid cannot detect
3238 the domain mismatch at certificate generation time when
3239 bump-server-first is used.
3242 NAME: sslpassword_program
3245 LOC: Config.Program.ssl_password
3248 Specify a program used for entering SSL key passphrases
3249 when using encrypted SSL certificate keys. If not specified
3250 keys must either be unencrypted, or Squid started with the -N
3251 option to allow it to query interactively for the passphrase.
3253 The key file name is given as argument to the program allowing
3254 selection of the right password if you have multiple encrypted
3259 OPTIONS RELATING TO EXTERNAL SSL_CRTD
3260 -----------------------------------------------------------------------------
3263 NAME: sslcrtd_program
3266 DEFAULT: @DEFAULT_SSL_CRTD@ -s @DEFAULT_SSL_DB_DIR@ -M 4MB
3267 LOC: Ssl::TheConfig.ssl_crtd
3269 Specify the location and options of the executable for certificate
3272 @DEFAULT_SSL_CRTD@ program can use a disk cache to improve response
3273 times on repeated requests. To enable caching, specify -s and -M
3274 parameters. If those parameters are not given, the program generates
3275 a new certificate on every request.
3277 For more information use:
3278 @DEFAULT_SSL_CRTD@ -h
3281 NAME: sslcrtd_children
3282 TYPE: HelperChildConfig
3284 DEFAULT: 32 startup=5 idle=1
3285 LOC: Ssl::TheConfig.ssl_crtdChildren
3287 The maximum number of processes spawn to service ssl server.
3288 The maximum this may be safely set to is 32.
3290 The startup= and idle= options allow some measure of skew in your
3295 Sets the minimum number of processes to spawn when Squid
3296 starts or reconfigures. When set to zero the first request will
3297 cause spawning of the first child process to handle it.
3299 Starting too few children temporary slows Squid under load while it
3300 tries to spawn enough additional processes to cope with traffic.
3304 Sets a minimum of how many processes Squid is to try and keep available
3305 at all times. When traffic begins to rise above what the existing
3306 processes can handle this many more will be spawned up to the maximum
3307 configured. A minimum setting of 1 is required.
3311 Sets the maximum number of queued requests.
3312 If the queued requests exceed queue size for more than 3 minutes
3313 squid aborts its operation.
3314 The default value is set to 2*numberofchildren.
3316 You must have at least one ssl_crtd process.
3319 NAME: sslcrtvalidator_program
3323 LOC: Ssl::TheConfig.ssl_crt_validator
3325 Specify the location and options of the executable for ssl_crt_validator
3328 Usage: sslcrtvalidator_program [ttl=n] [cache=n] path ...
3331 ttl=n TTL in seconds for cached results. The default is 60 secs
3332 cache=n limit the result cache size. The default value is 2048
3335 NAME: sslcrtvalidator_children
3336 TYPE: HelperChildConfig
3338 DEFAULT: 32 startup=5 idle=1 concurrency=1
3339 LOC: Ssl::TheConfig.ssl_crt_validator_Children
3341 The maximum number of processes spawn to service SSL server.
3342 The maximum this may be safely set to is 32.
3344 The startup= and idle= options allow some measure of skew in your
3349 Sets the minimum number of processes to spawn when Squid
3350 starts or reconfigures. When set to zero the first request will
3351 cause spawning of the first child process to handle it.
3353 Starting too few children temporary slows Squid under load while it
3354 tries to spawn enough additional processes to cope with traffic.
3358 Sets a minimum of how many processes Squid is to try and keep available
3359 at all times. When traffic begins to rise above what the existing
3360 processes can handle this many more will be spawned up to the maximum
3361 configured. A minimum setting of 1 is required.
3365 The number of requests each certificate validator helper can handle in
3366 parallel. A value of 0 indicates the certficate validator does not
3367 support concurrency. Defaults to 1.
3369 When this directive is set to a value >= 1 then the protocol
3370 used to communicate with the helper is modified to include
3371 a request ID in front of the request/response. The request
3372 ID from the request must be echoed back with the response
3377 Sets the maximum number of queued requests.
3378 If the queued requests exceed queue size for more than 3 minutes
3379 squid aborts its operation.
3380 The default value is set to 2*numberofchildren.
3382 You must have at least one ssl_crt_validator process.
3386 OPTIONS WHICH AFFECT THE NEIGHBOR SELECTION ALGORITHM
3387 -----------------------------------------------------------------------------
3395 To specify other caches in a hierarchy, use the format:
3397 cache_peer hostname type http-port icp-port [options]
3402 # hostname type port port options
3403 # -------------------- -------- ----- ----- -----------
3404 cache_peer parent.foo.net parent 3128 3130 default
3405 cache_peer sib1.foo.net sibling 3128 3130 proxy-only
3406 cache_peer sib2.foo.net sibling 3128 3130 proxy-only
3407 cache_peer example.com parent 80 0 default
3408 cache_peer cdn.example.com sibling 3128 0
3410 type: either 'parent', 'sibling', or 'multicast'.
3412 proxy-port: The port number where the peer accept HTTP requests.
3413 For other Squid proxies this is usually 3128
3414 For web servers this is usually 80
3416 icp-port: Used for querying neighbor caches about objects.
3417 Set to 0 if the peer does not support ICP or HTCP.
3418 See ICP and HTCP options below for additional details.
3421 ==== ICP OPTIONS ====
3423 You MUST also set icp_port and icp_access explicitly when using these options.
3424 The defaults will prevent peer traffic using ICP.
3427 no-query Disable ICP queries to this neighbor.
3430 Indicates the named peer is a member of a multicast group.
3431 ICP queries will not be sent directly to the peer, but ICP
3432 replies will be accepted from it.
3434 closest-only Indicates that, for ICP_OP_MISS replies, we'll only forward
3435 CLOSEST_PARENT_MISSes and never FIRST_PARENT_MISSes.
3438 To only send ICP queries to this neighbor infrequently.
3439 This is used to keep the neighbor round trip time updated
3440 and is usually used in conjunction with weighted-round-robin.
3443 ==== HTCP OPTIONS ====
3445 You MUST also set htcp_port and htcp_access explicitly when using these options.
3446 The defaults will prevent peer traffic using HTCP.
3449 htcp Send HTCP, instead of ICP, queries to the neighbor.
3450 You probably also want to set the "icp-port" to 4827
3451 instead of 3130. This directive accepts a comma separated
3452 list of options described below.
3454 htcp=oldsquid Send HTCP to old Squid versions (2.5 or earlier).
3456 htcp=no-clr Send HTCP to the neighbor but without
3457 sending any CLR requests. This cannot be used with
3460 htcp=only-clr Send HTCP to the neighbor but ONLY CLR requests.
3461 This cannot be used with no-clr.
3464 Send HTCP to the neighbor including CLRs but only when
3465 they do not result from PURGE requests.
3468 Forward any HTCP CLR requests this proxy receives to the peer.
3471 ==== PEER SELECTION METHODS ====
3473 The default peer selection method is ICP, with the first responding peer
3474 being used as source. These options can be used for better load balancing.
3477 default This is a parent cache which can be used as a "last-resort"
3478 if a peer cannot be located by any of the peer-selection methods.
3479 If specified more than once, only the first is used.
3481 round-robin Load-Balance parents which should be used in a round-robin
3482 fashion in the absence of any ICP queries.
3483 weight=N can be used to add bias.
3485 weighted-round-robin
3486 Load-Balance parents which should be used in a round-robin
3487 fashion with the frequency of each parent being based on the
3488 round trip time. Closer parents are used more often.
3489 Usually used for background-ping parents.
3490 weight=N can be used to add bias.
3492 carp Load-Balance parents which should be used as a CARP array.
3493 The requests will be distributed among the parents based on the
3494 CARP load balancing hash function based on their weight.
3496 userhash Load-balance parents based on the client proxy_auth or ident username.
3498 sourcehash Load-balance parents based on the client source IP.
3501 To be used only for cache peers of type "multicast".
3502 ALL members of this multicast group have "sibling"
3503 relationship with it, not "parent". This is to a multicast
3504 group when the requested object would be fetched only from
3505 a "parent" cache, anyway. It's useful, e.g., when
3506 configuring a pool of redundant Squid proxies, being
3507 members of the same multicast group.
3510 ==== PEER SELECTION OPTIONS ====
3512 weight=N use to affect the selection of a peer during any weighted
3513 peer-selection mechanisms.
3514 The weight must be an integer; default is 1,
3515 larger weights are favored more.
3516 This option does not affect parent selection if a peering
3517 protocol is not in use.
3519 basetime=N Specify a base amount to be subtracted from round trip
3521 It is subtracted before division by weight in calculating
3522 which parent to fectch from. If the rtt is less than the
3523 base time the rtt is set to a minimal value.
3525 ttl=N Specify a TTL to use when sending multicast ICP queries
3527 Only useful when sending to a multicast group.
3528 Because we don't accept ICP replies from random
3529 hosts, you must configure other group members as
3530 peers with the 'multicast-responder' option.
3532 no-delay To prevent access to this neighbor from influencing the
3535 digest-url=URL Tell Squid to fetch the cache digest (if digests are
3536 enabled) for this host from the specified URL rather
3537 than the Squid default location.
3540 ==== CARP OPTIONS ====
3542 carp-key=key-specification
3543 use a different key than the full URL to hash against the peer.
3544 the key-specification is a comma-separated list of the keywords
3545 scheme, host, port, path, params
3546 Order is not important.
3548 ==== ACCELERATOR / REVERSE-PROXY OPTIONS ====
3550 originserver Causes this parent to be contacted as an origin server.
3551 Meant to be used in accelerator setups when the peer
3555 Set the Host header of requests forwarded to this peer.
3556 Useful in accelerator setups where the server (peer)
3557 expects a certain domain name but clients may request
3558 others. ie example.com or www.example.com
3560 no-digest Disable request of cache digests.
3563 Disables requesting ICMP RTT database (NetDB).
3566 ==== AUTHENTICATION OPTIONS ====
3569 If this is a personal/workgroup proxy and your parent
3570 requires proxy authentication.
3572 Note: The string can include URL escapes (i.e. %20 for
3573 spaces). This also means % must be written as %%.
3576 Send login details received from client to this peer.
3577 Both Proxy- and WWW-Authorization headers are passed
3578 without alteration to the peer.
3579 Authentication is not required by Squid for this to work.
3581 Note: This will pass any form of authentication but
3582 only Basic auth will work through a proxy unless the
3583 connection-auth options are also used.
3585 login=PASS Send login details received from client to this peer.
3586 Authentication is not required by this option.
3588 If there are no client-provided authentication headers
3589 to pass on, but username and password are available
3590 from an external ACL user= and password= result tags
3591 they may be sent instead.
3593 Note: To combine this with proxy_auth both proxies must
3594 share the same user database as HTTP only allows for
3595 a single login (one for proxy, one for origin server).
3596 Also be warned this will expose your users proxy
3597 password to the peer. USE WITH CAUTION
3600 Send the username to the upstream cache, but with a
3601 fixed password. This is meant to be used when the peer
3602 is in another administrative domain, but it is still
3603 needed to identify each user.
3604 The star can optionally be followed by some extra
3605 information which is added to the username. This can
3606 be used to identify this proxy to the peer, similar to
3607 the login=username:password option above.
3610 If this is a personal/workgroup proxy and your parent
3611 requires a secure proxy authentication.
3612 The first principal from the default keytab or defined by
3613 the environment variable KRB5_KTNAME will be used.
3615 WARNING: The connection may transmit requests from multiple
3616 clients. Negotiate often assumes end-to-end authentication
3617 and a single-client. Which is not strictly true here.
3619 login=NEGOTIATE:principal_name
3620 If this is a personal/workgroup proxy and your parent
3621 requires a secure proxy authentication.
3622 The principal principal_name from the default keytab or
3623 defined by the environment variable KRB5_KTNAME will be
3626 WARNING: The connection may transmit requests from multiple
3627 clients. Negotiate often assumes end-to-end authentication
3628 and a single-client. Which is not strictly true here.
3630 connection-auth=on|off
3631 Tell Squid that this peer does or not support Microsoft
3632 connection oriented authentication, and any such
3633 challenges received from there should be ignored.
3634 Default is auto to automatically determine the status
3638 Do not use a keytab to authenticate to a peer when
3639 login=NEGOTIATE is specified. Let the GSSAPI
3640 implementation determine which already existing
3641 credentials cache to use instead.
3644 ==== SSL / HTTPS / TLS OPTIONS ====
3646 tls Encrypt connections to this peer with TLS.
3648 sslcert=/path/to/ssl/certificate
3649 A client X.509 certificate to use when connecting to
3652 sslkey=/path/to/ssl/key
3653 The private key corresponding to sslcert above.
3655 If sslkey= is not specified sslcert= is assumed to
3656 reference a PEM file containing both the certificate
3659 sslcipher=... The list of valid SSL ciphers to use when connecting
3663 The minimum TLS protocol version to permit. To control
3664 SSLv3 use the tls-options= parameter.
3665 Supported Values: 1.0 (default), 1.1, 1.2
3667 tls-options=... Specify various TLS implementation options.
3669 OpenSSL options most important are:
3671 NO_SSLv3 Disallow the use of SSLv3
3674 Always create a new key when using
3675 temporary/ephemeral DH key exchanges
3678 Disable use of RFC5077 session tickets.
3679 Some servers may have problems
3680 understanding the TLS extension due
3681 to ambiguous specification in RFC4507.
3683 ALL Enable various bug workarounds
3684 suggested as "harmless" by OpenSSL
3685 Be warned that this reduces SSL/TLS
3686 strength to some attacks.
3688 See the OpenSSL SSL_CTX_set_options documentation for a
3691 GnuTLS options most important are:
3694 Disable use of RFC5077 session tickets.
3695 Some servers may have problems
3696 understanding the TLS extension due
3697 to ambiguous specification in RFC4507.
3699 See the GnuTLS Priority Strings documentation
3700 for a more complete list.
3701 http://www.gnutls.org/manual/gnutls.html#Priority-Strings
3703 tls-cafile= PEM file containing CA certificates to use when verifying
3704 the peer certificate. May be repeated to load multiple files.
3706 sslcapath=... A directory containing additional CA certificates to
3707 use when verifying the peer certificate.
3708 Requires OpenSSL or LibreSSL.
3710 sslcrlfile=... A certificate revocation list file to use when
3711 verifying the peer certificate.
3713 sslflags=... Specify various flags modifying the SSL implementation:
3716 Accept certificates even if they fail to
3720 Don't verify the peer certificate
3721 matches the server name
3723 ssldomain= The peer name as advertised in it's certificate.
3724 Used for verifying the correctness of the received peer
3725 certificate. If not specified the peer hostname will be
3728 front-end-https[=off|on|auto]
3729 Enable the "Front-End-Https: On" header needed when
3730 using Squid as a SSL frontend in front of Microsoft OWA.
3731 See MS KB document Q307347 for details on this header.
3732 If set to auto the header will only be added if the
3733 request is forwarded as a https:// URL.
3735 tls-default-ca[=off]
3736 Whether to use the system Trusted CAs. Default is ON.
3738 tls-no-npn Do not use the TLS NPN extension to advertise HTTP/1.1.
3740 ==== GENERAL OPTIONS ====
3743 A peer-specific connect timeout.
3744 Also see the peer_connect_timeout directive.
3746 connect-fail-limit=N
3747 How many times connecting to a peer must fail before
3748 it is marked as down. Standby connection failures
3749 count towards this limit. Default is 10.
3751 allow-miss Disable Squid's use of only-if-cached when forwarding
3752 requests to siblings. This is primarily useful when
3753 icp_hit_stale is used by the sibling. Excessive use
3754 of this option may result in forwarding loops. One way
3755 to prevent peering loops when using this option, is to
3756 deny cache peer usage on requests from a peer:
3758 cache_peer_access peerName deny fromPeer
3760 max-conn=N Limit the number of concurrent connections the Squid
3761 may open to this peer, including already opened idle
3762 and standby connections. There is no peer-specific
3763 connection limit by default.
3765 A peer exceeding the limit is not used for new
3766 requests unless a standby connection is available.
3768 max-conn currently works poorly with idle persistent
3769 connections: When a peer reaches its max-conn limit,
3770 and there are idle persistent connections to the peer,
3771 the peer may not be selected because the limiting code
3772 does not know whether Squid can reuse those idle
3775 standby=N Maintain a pool of N "hot standby" connections to an
3776 UP peer, available for requests when no idle
3777 persistent connection is available (or safe) to use.
3778 By default and with zero N, no such pool is maintained.
3779 N must not exceed the max-conn limit (if any).
3781 At start or after reconfiguration, Squid opens new TCP
3782 standby connections until there are N connections
3783 available and then replenishes the standby pool as
3784 opened connections are used up for requests. A used
3785 connection never goes back to the standby pool, but
3786 may go to the regular idle persistent connection pool
3787 shared by all peers and origin servers.
3789 Squid never opens multiple new standby connections
3790 concurrently. This one-at-a-time approach minimizes
3791 flooding-like effect on peers. Furthermore, just a few
3792 standby connections should be sufficient in most cases
3793 to supply most new requests with a ready-to-use
3796 Standby connections obey server_idle_pconn_timeout.
3797 For the feature to work as intended, the peer must be
3798 configured to accept and keep them open longer than
3799 the idle timeout at the connecting Squid, to minimize
3800 race conditions typical to idle used persistent
3801 connections. Default request_timeout and
3802 server_idle_pconn_timeout values ensure such a
3805 name=xxx Unique name for the peer.
3806 Required if you have multiple peers on the same host
3807 but different ports.
3808 This name can be used in cache_peer_access and similar
3809 directives to identify the peer.
3810 Can be used by outgoing access controls through the
3813 no-tproxy Do not use the client-spoof TPROXY support when forwarding
3814 requests to this peer. Use normal address selection instead.
3815 This overrides the spoof_client_ip ACL.
3817 proxy-only objects fetched from the peer will not be stored locally.
3821 NAME: cache_peer_access
3824 DEFAULT_DOC: No peer usage restrictions.
3827 Restricts usage of cache_peer proxies.
3830 cache_peer_access peer-name allow|deny [!]aclname ...
3832 For the required peer-name parameter, use either the value of the
3833 cache_peer name=value parameter or, if name=value is missing, the
3834 cache_peer hostname parameter.
3836 This directive narrows down the selection of peering candidates, but
3837 does not determine the order in which the selected candidates are
3838 contacted. That order is determined by the peer selection algorithms
3839 (see PEER SELECTION sections in the cache_peer documentation).
3841 If a deny rule matches, the corresponding peer will not be contacted
3842 for the current transaction -- Squid will not send ICP queries and
3843 will not forward HTTP requests to that peer. An allow match leaves
3844 the corresponding peer in the selection. The first match for a given
3845 peer wins for that peer.
3847 The relative order of cache_peer_access directives for the same peer
3848 matters. The relative order of any two cache_peer_access directives
3849 for different peers does not matter. To ease interpretation, it is a
3850 good idea to group cache_peer_access directives for the same peer
3853 A single cache_peer_access directive may be evaluated multiple times
3854 for a given transaction because individual peer selection algorithms
3855 may check it independently from each other. These redundant checks
3856 may be optimized away in future Squid versions.
3858 This clause only supports fast acl types.
3859 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
3863 NAME: neighbor_type_domain
3864 TYPE: hostdomaintype
3866 DEFAULT_DOC: The peer type from cache_peer directive is used for all requests to that peer.
3869 Modify the cache_peer neighbor type when passing requests
3870 about specific domains to the peer.
3873 neighbor_type_domain neighbor parent|sibling domain domain ...
3876 cache_peer foo.example.com parent 3128 3130
3877 neighbor_type_domain foo.example.com sibling .au .de
3879 The above configuration treats all requests to foo.example.com as a
3880 parent proxy unless the request is for a .au or .de ccTLD domain name.
3883 NAME: dead_peer_timeout
3887 LOC: Config.Timeout.deadPeer
3889 This controls how long Squid waits to declare a peer cache
3890 as "dead." If there are no ICP replies received in this
3891 amount of time, Squid will declare the peer dead and not
3892 expect to receive any further ICP replies. However, it
3893 continues to send ICP queries, and will mark the peer as
3894 alive upon receipt of the first subsequent ICP reply.
3896 This timeout also affects when Squid expects to receive ICP
3897 replies from peers. If more than 'dead_peer' seconds have
3898 passed since the last ICP reply was received, Squid will not
3899 expect to receive an ICP reply on the next query. Thus, if
3900 your time between requests is greater than this timeout, you
3901 will see a lot of requests sent DIRECT to origin servers
3902 instead of to your parents.
3905 NAME: forward_max_tries
3908 LOC: Config.forward_max_tries
3910 Controls how many different forward paths Squid will try
3911 before giving up. See also forward_timeout.
3913 NOTE: connect_retries (default: none) can make each of these
3914 possible forwarding paths be tried multiple times.
3918 MEMORY CACHE OPTIONS
3919 -----------------------------------------------------------------------------
3926 LOC: Config.memMaxSize
3928 NOTE: THIS PARAMETER DOES NOT SPECIFY THE MAXIMUM PROCESS SIZE.
3929 IT ONLY PLACES A LIMIT ON HOW MUCH ADDITIONAL MEMORY SQUID WILL
3930 USE AS A MEMORY CACHE OF OBJECTS. SQUID USES MEMORY FOR OTHER
3931 THINGS AS WELL. SEE THE SQUID FAQ SECTION 8 FOR DETAILS.
3933 'cache_mem' specifies the ideal amount of memory to be used
3935 * In-Transit objects
3937 * Negative-Cached objects
3939 Data for these objects are stored in 4 KB blocks. This
3940 parameter specifies the ideal upper limit on the total size of
3941 4 KB blocks allocated. In-Transit objects take the highest
3944 In-transit objects have priority over the others. When
3945 additional space is needed for incoming data, negative-cached
3946 and hot objects will be released. In other words, the
3947 negative-cached and hot objects will fill up any unused space
3948 not needed for in-transit objects.
3950 If circumstances require, this limit will be exceeded.
3951 Specifically, if your incoming request rate requires more than
3952 'cache_mem' of memory to hold in-transit objects, Squid will
3953 exceed this limit to satisfy the new requests. When the load
3954 decreases, blocks will be freed until the high-water mark is
3955 reached. Thereafter, blocks will be used to store hot
3958 If shared memory caching is enabled, Squid does not use the shared
3959 cache space for in-transit objects, but they still consume as much
3960 local memory as they need. For more details about the shared memory
3961 cache, see memory_cache_shared.
3964 NAME: maximum_object_size_in_memory
3968 LOC: Config.Store.maxInMemObjSize
3970 Objects greater than this size will not be attempted to kept in
3971 the memory cache. This should be set high enough to keep objects
3972 accessed frequently in memory to improve performance whilst low
3973 enough to keep larger objects from hoarding cache_mem.
3976 NAME: memory_cache_shared
3979 LOC: Config.memShared
3981 DEFAULT_DOC: "on" where supported if doing memory caching with multiple SMP workers.
3983 Controls whether the memory cache is shared among SMP workers.
3985 The shared memory cache is meant to occupy cache_mem bytes and replace
3986 the non-shared memory cache, although some entities may still be
3987 cached locally by workers for now (e.g., internal and in-transit
3988 objects may be served from a local memory cache even if shared memory
3989 caching is enabled).
3991 By default, the memory cache is shared if and only if all of the
3992 following conditions are satisfied: Squid runs in SMP mode with
3993 multiple workers, cache_mem is positive, and Squid environment
3994 supports required IPC primitives (e.g., POSIX shared memory segments
3995 and GCC-style atomic operations).
3997 To avoid blocking locks, shared memory uses opportunistic algorithms
3998 that do not guarantee that every cachable entity that could have been
3999 shared among SMP workers will actually be shared.
4002 NAME: memory_cache_mode
4006 DEFAULT_DOC: Keep the most recently fetched objects in memory
4008 Controls which objects to keep in the memory cache (cache_mem)
4010 always Keep most recently fetched objects in memory (default)
4012 disk Only disk cache hits are kept in memory, which means
4013 an object must first be cached on disk and then hit
4014 a second time before cached in memory.
4016 network Only objects fetched from network is kept in memory
4019 NAME: memory_replacement_policy
4021 LOC: Config.memPolicy
4024 The memory replacement policy parameter determines which
4025 objects are purged from memory when memory space is needed.
4027 See cache_replacement_policy for details on algorithms.
4032 -----------------------------------------------------------------------------
4035 NAME: cache_replacement_policy
4037 LOC: Config.replPolicy
4040 The cache replacement policy parameter determines which
4041 objects are evicted (replaced) when disk space is needed.
4043 lru : Squid's original list based LRU policy
4044 heap GDSF : Greedy-Dual Size Frequency
4045 heap LFUDA: Least Frequently Used with Dynamic Aging
4046 heap LRU : LRU policy implemented using a heap
4048 Applies to any cache_dir lines listed below this directive.
4050 The LRU policies keeps recently referenced objects.
4052 The heap GDSF policy optimizes object hit rate by keeping smaller
4053 popular objects in cache so it has a better chance of getting a
4054 hit. It achieves a lower byte hit rate than LFUDA though since
4055 it evicts larger (possibly popular) objects.
4057 The heap LFUDA policy keeps popular objects in cache regardless of
4058 their size and thus optimizes byte hit rate at the expense of
4059 hit rate since one large, popular object will prevent many
4060 smaller, slightly less popular objects from being cached.
4062 Both policies utilize a dynamic aging mechanism that prevents
4063 cache pollution that can otherwise occur with frequency-based
4064 replacement policies.
4066 NOTE: if using the LFUDA replacement policy you should increase
4067 the value of maximum_object_size above its default of 4 MB to
4068 to maximize the potential byte hit rate improvement of LFUDA.
4070 For more information about the GDSF and LFUDA cache replacement
4071 policies see http://www.hpl.hp.com/techreports/1999/HPL-1999-69.html
4072 and http://fog.hpl.external.hp.com/techreports/98/HPL-98-173.html.
4075 NAME: minimum_object_size
4079 DEFAULT_DOC: no limit
4080 LOC: Config.Store.minObjectSize
4082 Objects smaller than this size will NOT be saved on disk. The
4083 value is specified in bytes, and the default is 0 KB, which
4084 means all responses can be stored.
4087 NAME: maximum_object_size
4091 LOC: Config.Store.maxObjectSize
4093 Set the default value for max-size parameter on any cache_dir.
4094 The value is specified in bytes, and the default is 4 MB.
4096 If you wish to get a high BYTES hit ratio, you should probably
4097 increase this (one 32 MB object hit counts for 3200 10KB
4100 If you wish to increase hit ratio more than you want to
4101 save bandwidth you should leave this low.
4103 NOTE: if using the LFUDA replacement policy you should increase
4104 this value to maximize the byte hit rate improvement of LFUDA!
4105 See cache_replacement_policy for a discussion of this policy.
4111 DEFAULT_DOC: No disk cache. Store cache ojects only in memory.
4112 LOC: Config.cacheSwap
4115 cache_dir Type Directory-Name Fs-specific-data [options]
4117 You can specify multiple cache_dir lines to spread the
4118 cache among different disk partitions.
4120 Type specifies the kind of storage system to use. Only "ufs"
4121 is built by default. To enable any of the other storage systems
4122 see the --enable-storeio configure option.
4124 'Directory' is a top-level directory where cache swap
4125 files will be stored. If you want to use an entire disk
4126 for caching, this can be the mount-point directory.
4127 The directory must exist and be writable by the Squid
4128 process. Squid will NOT create this directory for you.
4130 In SMP configurations, cache_dir must not precede the workers option
4131 and should use configuration macros or conditionals to give each
4132 worker interested in disk caching a dedicated cache directory.
4135 ==== The ufs store type ====
4137 "ufs" is the old well-known Squid storage format that has always
4141 cache_dir ufs Directory-Name Mbytes L1 L2 [options]
4143 'Mbytes' is the amount of disk space (MB) to use under this
4144 directory. The default is 100 MB. Change this to suit your
4145 configuration. Do NOT put the size of your disk drive here.
4146 Instead, if you want Squid to use the entire disk drive,
4147 subtract 20% and use that value.
4149 'L1' is the number of first-level subdirectories which
4150 will be created under the 'Directory'. The default is 16.
4152 'L2' is the number of second-level subdirectories which
4153 will be created under each first-level directory. The default
4157 ==== The aufs store type ====
4159 "aufs" uses the same storage format as "ufs", utilizing
4160 POSIX-threads to avoid blocking the main Squid process on
4161 disk-I/O. This was formerly known in Squid as async-io.
4164 cache_dir aufs Directory-Name Mbytes L1 L2 [options]
4166 see argument descriptions under ufs above
4169 ==== The diskd store type ====
4171 "diskd" uses the same storage format as "ufs", utilizing a
4172 separate process to avoid blocking the main Squid process on
4176 cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n]
4178 see argument descriptions under ufs above
4180 Q1 specifies the number of unacknowledged I/O requests when Squid
4181 stops opening new files. If this many messages are in the queues,
4182 Squid won't open new files. Default is 64
4184 Q2 specifies the number of unacknowledged messages when Squid
4185 starts blocking. If this many messages are in the queues,
4186 Squid blocks until it receives some replies. Default is 72
4188 When Q1 < Q2 (the default), the cache directory is optimized
4189 for lower response time at the expense of a decrease in hit
4190 ratio. If Q1 > Q2, the cache directory is optimized for
4191 higher hit ratio at the expense of an increase in response
4195 ==== The rock store type ====
4198 cache_dir rock Directory-Name Mbytes [options]
4200 The Rock Store type is a database-style storage. All cached
4201 entries are stored in a "database" file, using fixed-size slots.
4202 A single entry occupies one or more slots.
4204 If possible, Squid using Rock Store creates a dedicated kid
4205 process called "disker" to avoid blocking Squid worker(s) on disk
4206 I/O. One disker kid is created for each rock cache_dir. Diskers
4207 are created only when Squid, running in daemon mode, has support
4208 for the IpcIo disk I/O module.
4210 swap-timeout=msec: Squid will not start writing a miss to or
4211 reading a hit from disk if it estimates that the swap operation
4212 will take more than the specified number of milliseconds. By
4213 default and when set to zero, disables the disk I/O time limit
4214 enforcement. Ignored when using blocking I/O module because
4215 blocking synchronous I/O does not allow Squid to estimate the
4216 expected swap wait time.
4218 max-swap-rate=swaps/sec: Artificially limits disk access using
4219 the specified I/O rate limit. Swap out requests that
4220 would cause the average I/O rate to exceed the limit are
4221 delayed. Individual swap in requests (i.e., hits or reads) are
4222 not delayed, but they do contribute to measured swap rate and
4223 since they are placed in the same FIFO queue as swap out
4224 requests, they may wait longer if max-swap-rate is smaller.
4225 This is necessary on file systems that buffer "too
4226 many" writes and then start blocking Squid and other processes
4227 while committing those writes to disk. Usually used together
4228 with swap-timeout to avoid excessive delays and queue overflows
4229 when disk demand exceeds available disk "bandwidth". By default
4230 and when set to zero, disables the disk I/O rate limit
4231 enforcement. Currently supported by IpcIo module only.
4233 slot-size=bytes: The size of a database "record" used for
4234 storing cached responses. A cached response occupies at least
4235 one slot and all database I/O is done using individual slots so
4236 increasing this parameter leads to more disk space waste while
4237 decreasing it leads to more disk I/O overheads. Should be a
4238 multiple of your operating system I/O page size. Defaults to
4239 16KBytes. A housekeeping header is stored with each slot and
4240 smaller slot-sizes will be rejected. The header is smaller than
4244 ==== COMMON OPTIONS ====
4246 no-store no new objects should be stored to this cache_dir.
4248 min-size=n the minimum object size in bytes this cache_dir
4249 will accept. It's used to restrict a cache_dir
4250 to only store large objects (e.g. AUFS) while
4251 other stores are optimized for smaller objects
4255 max-size=n the maximum object size in bytes this cache_dir
4257 The value in maximum_object_size directive sets
4258 the default unless more specific details are
4259 available (ie a small store capacity).
4261 Note: To make optimal use of the max-size limits you should order
4262 the cache_dir lines with the smallest max-size value first.
4266 # Uncomment and adjust the following to add a disk cache directory.
4267 #cache_dir ufs @DEFAULT_SWAP_DIR@ 100 16 256
4271 NAME: store_dir_select_algorithm
4273 LOC: Config.store_dir_select_algorithm
4276 How Squid selects which cache_dir to use when the response
4277 object will fit into more than one.
4279 Regardless of which algorithm is used the cache_dir min-size
4280 and max-size parameters are obeyed. As such they can affect
4281 the selection algorithm by limiting the set of considered
4288 This algorithm is suited to caches with similar cache_dir
4289 sizes and disk speeds.
4291 The disk with the least I/O pending is selected.
4292 When there are multiple disks with the same I/O load ranking
4293 the cache_dir with most available capacity is selected.
4295 When a mix of cache_dir sizes are configured the faster disks
4296 have a naturally lower I/O loading and larger disks have more
4297 capacity. So space used to store objects and data throughput
4298 may be very unbalanced towards larger disks.
4303 This algorithm is suited to caches with unequal cache_dir
4306 Each cache_dir is selected in a rotation. The next suitable
4309 Available cache_dir capacity is only considered in relation
4310 to whether the object will fit and meets the min-size and
4311 max-size parameters.
4313 Disk I/O loading is only considered to prevent overload on slow
4314 disks. This algorithm does not spread objects by size, so any
4315 I/O loading per-disk may appear very unbalanced and volatile.
4317 If several cache_dirs use similar min-size, max-size, or other
4318 limits to to reject certain responses, then do not group such
4319 cache_dir lines together, to avoid round-robin selection bias
4320 towards the first cache_dir after the group. Instead, interleave
4321 cache_dir lines from different groups. For example:
4323 store_dir_select_algorithm round-robin
4324 cache_dir rock /hdd1 ... min-size=100000
4325 cache_dir rock /ssd1 ... max-size=99999
4326 cache_dir rock /hdd2 ... min-size=100000
4327 cache_dir rock /ssd2 ... max-size=99999
4328 cache_dir rock /hdd3 ... min-size=100000
4329 cache_dir rock /ssd3 ... max-size=99999
4332 NAME: max_open_disk_fds
4334 LOC: Config.max_open_disk_fds
4336 DEFAULT_DOC: no limit
4338 To avoid having disk as the I/O bottleneck Squid can optionally
4339 bypass the on-disk cache if more than this amount of disk file
4340 descriptors are open.
4342 A value of 0 indicates no limit.
4345 NAME: cache_swap_low
4346 COMMENT: (percent, 0-100)
4349 LOC: Config.Swap.lowWaterMark
4351 The low-water mark for AUFS/UFS/diskd cache object eviction by
4352 the cache_replacement_policy algorithm.
4354 Removal begins when the swap (disk) usage of a cache_dir is
4355 above this low-water mark and attempts to maintain utilization
4356 near the low-water mark.
4358 As swap utilization increases towards the high-water mark set
4359 by cache_swap_high object eviction becomes more agressive.
4361 The value difference in percentages between low- and high-water
4362 marks represent an eviction rate of 300 objects per second and
4363 the rate continues to scale in agressiveness by multiples of
4364 this above the high-water mark.
4366 Defaults are 90% and 95%. If you have a large cache, 5% could be
4367 hundreds of MB. If this is the case you may wish to set these
4368 numbers closer together.
4370 See also cache_swap_high and cache_replacement_policy
4373 NAME: cache_swap_high
4374 COMMENT: (percent, 0-100)
4377 LOC: Config.Swap.highWaterMark
4379 The high-water mark for AUFS/UFS/diskd cache object eviction by
4380 the cache_replacement_policy algorithm.
4382 Removal begins when the swap (disk) usage of a cache_dir is
4383 above the low-water mark set by cache_swap_low and attempts to
4384 maintain utilization near the low-water mark.
4386 As swap utilization increases towards this high-water mark object
4387 eviction becomes more agressive.
4389 The value difference in percentages between low- and high-water
4390 marks represent an eviction rate of 300 objects per second and
4391 the rate continues to scale in agressiveness by multiples of
4392 this above the high-water mark.
4394 Defaults are 90% and 95%. If you have a large cache, 5% could be
4395 hundreds of MB. If this is the case you may wish to set these
4396 numbers closer together.
4398 See also cache_swap_low and cache_replacement_policy
4403 -----------------------------------------------------------------------------
4410 DEFAULT_DOC: The format definitions squid, common, combined, referrer, useragent are built in.
4414 logformat <name> <format specification>
4416 Defines an access log format.
4418 The <format specification> is a string with embedded % format codes
4420 % format codes all follow the same basic structure where all but
4421 the formatcode is optional. Output strings are automatically escaped
4422 as required according to their context and the output format
4423 modifiers are usually not needed, but can be specified if an explicit
4424 output format is desired.
4426 % ["|[|'|#|/] [-] [[0]width] [{arg}] formatcode [{arg}]
4428 " output in quoted string format
4429 [ output in squid text log format as used by log_mime_hdrs
4430 # output in URL quoted format
4431 / output in shell \-escaped format
4436 width minimum and/or maximum field width:
4437 [width_min][.width_max]
4438 When minimum starts with 0, the field is zero-padded.
4439 String values exceeding maximum width are truncated.
4441 {arg} argument such as header name etc. This field may be
4442 placed before or after the token, but not both at once.
4446 % a literal % character
4447 sn Unique sequence number per log line entry
4448 err_code The ID of an error response served by Squid or
4449 a similar internal error identifier.
4450 err_detail Additional err_code-dependent error information.
4451 note The annotation specified by the argument. Also
4452 logs the adaptation meta headers set by the
4453 adaptation_meta configuration parameter.
4454 If no argument given all annotations logged.
4455 The argument may include a separator to use with
4458 By default, multiple note values are separated with ","
4459 and multiple notes are separated with "\r\n".
4460 When logging named notes with %{name}note, the
4461 explicitly configured separator is used between note
4462 values. When logging all notes with %note, the
4463 explicitly configured separator is used between
4464 individual notes. There is currently no way to
4465 specify both value and notes separators when logging
4466 all notes with %note.
4468 Connection related format codes:
4470 >a Client source IP address
4472 >p Client source port
4473 >eui Client source EUI (MAC address, EUI-48 or EUI-64 identifier)
4474 >la Local IP address the client connected to
4475 >lp Local port number the client connected to
4476 >qos Client connection TOS/DSCP value set by Squid
4477 >nfmark Client connection netfilter packet MARK set by Squid
4479 la Local listening IP address the client connection was connected to.
4480 lp Local listening port number the client connection was connected to.
4482 <a Server IP address of the last server or peer connection
4483 <A Server FQDN or peer name
4484 <p Server port number of the last server or peer connection
4485 <la Local IP address of the last server or peer connection
4486 <lp Local port number of the last server or peer connection
4487 <qos Server connection TOS/DSCP value set by Squid
4488 <nfmark Server connection netfilter packet MARK set by Squid
4490 Time related format codes:
4492 ts Seconds since epoch
4493 tu subsecond time (milliseconds)
4494 tl Local time. Optional strftime format argument
4495 default %d/%b/%Y:%H:%M:%S %z
4496 tg GMT time. Optional strftime format argument
4497 default %d/%b/%Y:%H:%M:%S %z
4498 tr Response time (milliseconds)
4499 dt Total time spent making DNS lookups (milliseconds)
4500 tS Approximate master transaction start time in
4501 <full seconds since epoch>.<fractional seconds> format.
4502 Currently, Squid considers the master transaction
4503 started when a complete HTTP request header initiating
4504 the transaction is received from the client. This is
4505 the same value that Squid uses to calculate transaction
4506 response time when logging %tr to access.log. Currently,
4507 Squid uses millisecond resolution for %tS values,
4508 similar to the default access.log "current time" field
4511 Access Control related format codes:
4513 et Tag returned by external acl
4514 ea Log string returned by external acl
4515 un User name (any available)
4516 ul User name from authentication
4517 ue User name from external acl helper
4518 ui User name from ident
4519 un A user name. Expands to the first available name
4520 from the following list of information sources:
4521 - authenticated user name, like %ul
4522 - user name supplied by an external ACL, like %ue
4523 - SSL client name, like %us
4524 - ident user name, like %ui
4525 credentials Client credentials. The exact meaning depends on
4526 the authentication scheme: For Basic authentication,
4527 it is the password; for Digest, the realm sent by the
4528 client; for NTLM and Negotiate, the client challenge
4529 or client credentials prefixed with "YR " or "KK ".
4531 HTTP related format codes:
4535 [http::]rm Request method (GET/POST etc)
4536 [http::]>rm Request method from client
4537 [http::]<rm Request method sent to server or peer
4538 [http::]ru Request URL from client (historic, filtered for logging)
4539 [http::]>ru Request URL from client
4540 [http::]<ru Request URL sent to server or peer
4541 [http::]>rs Request URL scheme from client
4542 [http::]<rs Request URL scheme sent to server or peer
4543 [http::]>rd Request URL domain from client
4544 [http::]<rd Request URL domain sent to server or peer
4545 [http::]>rP Request URL port from client
4546 [http::]<rP Request URL port sent to server or peer
4547 [http::]rp Request URL path excluding hostname
4548 [http::]>rp Request URL path excluding hostname from client
4549 [http::]<rp Request URL path excluding hostname sent to server or peer
4550 [http::]rv Request protocol version
4551 [http::]>rv Request protocol version from client
4552 [http::]<rv Request protocol version sent to server or peer
4554 [http::]>h Original received request header.
4555 Usually differs from the request header sent by
4556 Squid, although most fields are often preserved.
4557 Accepts optional header field name/value filter
4558 argument using name[:[separator]element] format.
4559 [http::]>ha Received request header after adaptation and
4560 redirection (pre-cache REQMOD vectoring point).
4561 Usually differs from the request header sent by
4562 Squid, although most fields are often preserved.
4563 Optional header name argument as for >h
4567 [http::]<Hs HTTP status code received from the next hop
4568 [http::]>Hs HTTP status code sent to the client
4570 [http::]<h Reply header. Optional header name argument
4573 [http::]mt MIME content type
4578 [http::]st Total size of request + reply traffic with client
4579 [http::]>st Total size of request received from client.
4580 Excluding chunked encoding bytes.
4581 [http::]<st Total size of reply sent to client (after adaptation)
4583 [http::]>sh Size of request headers received from client
4584 [http::]<sh Size of reply headers sent to client (after adaptation)
4586 [http::]<sH Reply high offset sent
4587 [http::]<sS Upstream object size
4589 [http::]<bs Number of HTTP-equivalent message body bytes
4590 received from the next hop, excluding chunked
4591 transfer encoding and control messages.
4592 Generated FTP/Gopher listings are treated as
4597 [http::]<pt Peer response time in milliseconds. The timer starts
4598 when the last request byte is sent to the next hop
4599 and stops when the last response byte is received.
4600 [http::]<tt Total time in milliseconds. The timer
4601 starts with the first connect request (or write I/O)
4602 sent to the first selected peer. The timer stops
4603 with the last I/O with the last peer.
4605 Squid handling related format codes:
4607 Ss Squid request status (TCP_MISS etc)
4608 Sh Squid hierarchy status (DEFAULT_PARENT etc)
4610 SSL-related format codes:
4612 ssl::bump_mode SslBump decision for the transaction:
4614 For CONNECT requests that initiated bumping of
4615 a connection and for any request received on
4616 an already bumped connection, Squid logs the
4617 corresponding SslBump mode ("splice", "bump",
4618 "peek", "stare", "terminate", "server-first"
4619 or "client-first"). See the ssl_bump option
4620 for more information about these modes.
4622 A "none" token is logged for requests that
4623 triggered "ssl_bump" ACL evaluation matching
4626 In all other cases, a single dash ("-") is
4629 ssl::>sni SSL client SNI sent to Squid.
4632 The Subject field of the received client
4633 SSL certificate or a dash ('-') if Squid has
4634 received an invalid/malformed certificate or
4635 no certificate at all. Consider encoding the
4636 logged value because Subject often has spaces.
4639 The Issuer field of the received client
4640 SSL certificate or a dash ('-') if Squid has
4641 received an invalid/malformed certificate or
4642 no certificate at all. Consider encoding the
4643 logged value because Issuer often has spaces.
4646 The Subject field of the received server
4647 TLS certificate or a dash ('-') if this is
4648 not available. Consider encoding the logged
4649 value because Subject often has spaces.
4652 The Issuer field of the received server
4653 TLS certificate or a dash ('-') if this is
4654 not available. Consider encoding the logged
4655 value because Issuer often has spaces.
4658 The list of certificate validation errors
4659 detected by Squid (including OpenSSL and
4660 certificate validation helper components). The
4661 errors are listed in the discovery order. By
4662 default, the error codes are separated by ':'.
4663 Accepts an optional separator argument.
4665 %ssl::>negotiated_version The negotiated TLS version of the
4668 %ssl::<negotiated_version The negotiated TLS version of the
4669 last server or peer connection.
4671 %ssl::>received_hello_version The TLS version of the Hello
4672 message received from TLS client.
4674 %ssl::<received_hello_version The TLS version of the Hello
4675 message received from TLS server.
4677 %ssl::>received_supported_version The maximum TLS version
4678 supported by the TLS client.
4680 %ssl::<received_supported_version The maximum TLS version
4681 supported by the TLS server.
4683 %ssl::>negotiated_cipher The negotiated cipher of the
4686 %ssl::<negotiated_cipher The negotiated cipher of the
4687 last server or peer connection.
4689 If ICAP is enabled, the following code becomes available (as
4690 well as ICAP log codes documented with the icap_log option):
4692 icap::tt Total ICAP processing time for the HTTP
4693 transaction. The timer ticks when ICAP
4694 ACLs are checked and when ICAP
4695 transaction is in progress.
4697 If adaptation is enabled the following codes become available:
4699 adapt::<last_h The header of the last ICAP response or
4700 meta-information from the last eCAP
4701 transaction related to the HTTP transaction.
4702 Like <h, accepts an optional header name
4705 adapt::sum_trs Summed adaptation transaction response
4706 times recorded as a comma-separated list in
4707 the order of transaction start time. Each time
4708 value is recorded as an integer number,
4709 representing response time of one or more
4710 adaptation (ICAP or eCAP) transaction in
4711 milliseconds. When a failed transaction is
4712 being retried or repeated, its time is not
4713 logged individually but added to the
4714 replacement (next) transaction. See also:
4717 adapt::all_trs All adaptation transaction response times.
4718 Same as adaptation_strs but response times of
4719 individual transactions are never added
4720 together. Instead, all transaction response
4721 times are recorded individually.
4723 You can prefix adapt::*_trs format codes with adaptation
4724 service name in curly braces to record response time(s) specific
4725 to that service. For example: %{my_service}adapt::sum_trs
4727 The default formats available (which do not need re-defining) are:
4729 logformat squid %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %[un %Sh/%<a %mt
4730 logformat common %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st %Ss:%Sh
4731 logformat combined %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
4732 logformat referrer %ts.%03tu %>a %{Referer}>h %ru
4733 logformat useragent %>a [%tl] "%{User-Agent}>h"
4735 NOTE: When the log_mime_hdrs directive is set to ON.
4736 The squid, common and combined formats have a safely encoded copy
4737 of the mime headers appended to each line within a pair of brackets.
4739 NOTE: The common and combined formats are not quite true to the Apache definition.
4740 The logs from Squid contain an extra status and hierarchy code appended.
4744 NAME: access_log cache_access_log
4746 LOC: Config.Log.accesslogs
4747 DEFAULT_IF_NONE: daemon:@DEFAULT_ACCESS_LOG@ squid
4749 Configures whether and how Squid logs HTTP and ICP transactions.
4750 If access logging is enabled, a single line is logged for every
4751 matching HTTP or ICP request. The recommended directive formats are:
4753 access_log <module>:<place> [option ...] [acl acl ...]
4754 access_log none [acl acl ...]
4756 The following directive format is accepted but may be deprecated:
4757 access_log <module>:<place> [<logformat name> [acl acl ...]]
4759 In most cases, the first ACL name must not contain the '=' character
4760 and should not be equal to an existing logformat name. You can always
4761 start with an 'all' ACL to work around those restrictions.
4763 Will log to the specified module:place using the specified format (which
4764 must be defined in a logformat directive) those entries which match
4765 ALL the acl's specified (which must be defined in acl clauses).
4766 If no acl is specified, all requests will be logged to this destination.
4768 ===== Available options for the recommended directive format =====
4770 logformat=name Names log line format (either built-in or
4771 defined by a logformat directive). Defaults
4774 buffer-size=64KB Defines approximate buffering limit for log
4775 records (see buffered_logs). Squid should not
4776 keep more than the specified size and, hence,
4777 should flush records before the buffer becomes
4778 full to avoid overflows under normal
4779 conditions (the exact flushing algorithm is
4780 module-dependent though). The on-error option
4781 controls overflow handling.
4783 on-error=die|drop Defines action on unrecoverable errors. The
4784 'drop' action ignores (i.e., does not log)
4785 affected log records. The default 'die' action
4786 kills the affected worker. The drop action
4787 support has not been tested for modules other
4790 rotate=N Specifies the number of log file rotations to
4791 make when you run 'squid -k rotate'. The default
4792 is to obey the logfile_rotate directive. Setting
4793 rotate=0 will disable the file name rotation,
4794 but the log files are still closed and re-opened.
4795 This will enable you to rename the logfiles
4796 yourself just before sending the rotate signal.
4797 Only supported by the stdio module.
4799 ===== Modules Currently available =====
4801 none Do not log any requests matching these ACL.
4802 Do not specify Place or logformat name.
4804 stdio Write each log line to disk immediately at the completion of
4806 Place: the filename and path to be written.
4808 daemon Very similar to stdio. But instead of writing to disk the log
4809 line is passed to a daemon helper for asychronous handling instead.
4810 Place: varies depending on the daemon.
4812 log_file_daemon Place: the file name and path to be written.
4814 syslog To log each request via syslog facility.
4815 Place: The syslog facility and priority level for these entries.
4816 Place Format: facility.priority
4818 where facility could be any of:
4819 authpriv, daemon, local0 ... local7 or user.
4821 And priority could be any of:
4822 err, warning, notice, info, debug.
4824 udp To send each log line as text data to a UDP receiver.
4825 Place: The destination host name or IP and port.
4826 Place Format: //host:port
4828 tcp To send each log line as text data to a TCP receiver.
4829 Lines may be accumulated before sending (see buffered_logs).
4830 Place: The destination host name or IP and port.
4831 Place Format: //host:port
4834 access_log daemon:@DEFAULT_ACCESS_LOG@ squid
4840 LOC: Config.Log.icaplogs
4843 ICAP log files record ICAP transaction summaries, one line per
4846 The icap_log option format is:
4847 icap_log <filepath> [<logformat name> [acl acl ...]]
4848 icap_log none [acl acl ...]]
4850 Please see access_log option documentation for details. The two
4851 kinds of logs share the overall configuration approach and many
4854 ICAP processing of a single HTTP message or transaction may
4855 require multiple ICAP transactions. In such cases, multiple
4856 ICAP transaction log lines will correspond to a single access
4859 ICAP log supports many access.log logformat %codes. In ICAP context,
4860 HTTP message-related %codes are applied to the HTTP message embedded
4861 in an ICAP message. Logformat "%http::>..." codes are used for HTTP
4862 messages embedded in ICAP requests while "%http::<..." codes are used
4863 for HTTP messages embedded in ICAP responses. For example:
4865 http::>h To-be-adapted HTTP message headers sent by Squid to
4866 the ICAP service. For REQMOD transactions, these are
4867 HTTP request headers. For RESPMOD, these are HTTP
4868 response headers, but Squid currently cannot log them
4869 (i.e., %http::>h will expand to "-" for RESPMOD).
4871 http::<h Adapted HTTP message headers sent by the ICAP
4872 service to Squid (i.e., HTTP request headers in regular
4873 REQMOD; HTTP response headers in RESPMOD and during
4874 request satisfaction in REQMOD).
4876 ICAP OPTIONS transactions do not embed HTTP messages.
4878 Several logformat codes below deal with ICAP message bodies. An ICAP
4879 message body, if any, typically includes a complete HTTP message
4880 (required HTTP headers plus optional HTTP message body). When
4881 computing HTTP message body size for these logformat codes, Squid
4882 either includes or excludes chunked encoding overheads; see
4883 code-specific documentation for details.
4885 For Secure ICAP services, all size-related information is currently
4886 computed before/after TLS encryption/decryption, as if TLS was not
4889 The following format codes are also available for ICAP logs:
4891 icap::<A ICAP server IP address. Similar to <A.
4893 icap::<service_name ICAP service name from the icap_service
4894 option in Squid configuration file.
4896 icap::ru ICAP Request-URI. Similar to ru.
4898 icap::rm ICAP request method (REQMOD, RESPMOD, or
4899 OPTIONS). Similar to existing rm.
4901 icap::>st The total size of the ICAP request sent to the ICAP
4902 server (ICAP headers + ICAP body), including chunking
4905 icap::<st The total size of the ICAP response received from the
4906 ICAP server (ICAP headers + ICAP body), including
4907 chunking metadata (if any).
4909 icap::<bs The size of the ICAP response body received from the
4910 ICAP server, excluding chunking metadata (if any).
4912 icap::tr Transaction response time (in
4913 milliseconds). The timer starts when
4914 the ICAP transaction is created and
4915 stops when the transaction is completed.
4918 icap::tio Transaction I/O time (in milliseconds). The
4919 timer starts when the first ICAP request
4920 byte is scheduled for sending. The timers
4921 stops when the last byte of the ICAP response
4924 icap::to Transaction outcome: ICAP_ERR* for all
4925 transaction errors, ICAP_OPT for OPTION
4926 transactions, ICAP_ECHO for 204
4927 responses, ICAP_MOD for message
4928 modification, and ICAP_SAT for request
4929 satisfaction. Similar to Ss.
4931 icap::Hs ICAP response status code. Similar to Hs.
4933 icap::>h ICAP request header(s). Similar to >h.
4935 icap::<h ICAP response header(s). Similar to <h.
4937 The default ICAP log format, which can be used without an explicit
4938 definition, is called icap_squid:
4940 logformat icap_squid %ts.%03tu %6icap::tr %>A %icap::to/%03icap::Hs %icap::<st %icap::rm %icap::ru %un -/%icap::<A -
4942 See also: logformat and %adapt::<last_h
4945 NAME: logfile_daemon
4947 DEFAULT: @DEFAULT_LOGFILED@
4948 LOC: Log::TheConfig.logfile_daemon
4950 Specify the path to the logfile-writing daemon. This daemon is
4951 used to write the access and store logs, if configured.
4953 Squid sends a number of commands to the log daemon:
4954 L<data>\n - logfile data
4959 r<n>\n - set rotate count to <n>
4960 b<n>\n - 1 = buffer output, 0 = don't buffer output
4962 No responses is expected.
4965 NAME: stats_collection
4967 LOC: Config.accessList.stats_collection
4969 DEFAULT_DOC: Allow logging for all transactions.
4970 COMMENT: allow|deny acl acl...
4972 This options allows you to control which requests gets accounted
4973 in performance counters.
4975 This clause only supports fast acl types.
4976 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4979 NAME: cache_store_log
4982 LOC: Config.Log.store
4984 Logs the activities of the storage manager. Shows which
4985 objects are ejected from the cache, and which objects are
4986 saved and for how long.
4987 There are not really utilities to analyze this data, so you can safely
4988 disable it (the default).
4990 Store log uses modular logging outputs. See access_log for the list
4991 of modules supported.
4994 cache_store_log stdio:@DEFAULT_STORE_LOG@
4995 cache_store_log daemon:@DEFAULT_STORE_LOG@
4998 NAME: cache_swap_state cache_swap_log
5000 LOC: Config.Log.swap
5002 DEFAULT_DOC: Store the journal inside its cache_dir
5004 Location for the cache "swap.state" file. This index file holds
5005 the metadata of objects saved on disk. It is used to rebuild
5006 the cache during startup. Normally this file resides in each
5007 'cache_dir' directory, but you may specify an alternate
5008 pathname here. Note you must give a full filename, not just
5009 a directory. Since this is the index for the whole object
5010 list you CANNOT periodically rotate it!
5012 If %s can be used in the file name it will be replaced with a
5013 a representation of the cache_dir name where each / is replaced
5014 with '.'. This is needed to allow adding/removing cache_dir
5015 lines when cache_swap_log is being used.
5017 If have more than one 'cache_dir', and %s is not used in the name
5018 these swap logs will have names such as:
5024 The numbered extension (which is added automatically)
5025 corresponds to the order of the 'cache_dir' lines in this
5026 configuration file. If you change the order of the 'cache_dir'
5027 lines in this file, these index files will NOT correspond to
5028 the correct 'cache_dir' entry (unless you manually rename
5029 them). We recommend you do NOT use this option. It is
5030 better to keep these index files in each 'cache_dir' directory.
5033 NAME: logfile_rotate
5036 LOC: Config.Log.rotateNumber
5038 Specifies the default number of logfile rotations to make when you
5039 type 'squid -k rotate'. The default is 10, which will rotate
5040 with extensions 0 through 9. Setting logfile_rotate to 0 will
5041 disable the file name rotation, but the logfiles are still closed
5042 and re-opened. This will enable you to rename the logfiles
5043 yourself just before sending the rotate signal.
5045 Note, from Squid-3.1 this option is only a default for cache.log,
5046 that log can be rotated separately by using debug_options.
5048 Note, from Squid-4 this option is only a default for access.log
5049 recorded by stdio: module. Those logs can be rotated separately by
5050 using the rotate=N option on their access_log directive.
5052 Note, the 'squid -k rotate' command normally sends a USR1
5053 signal to the running squid process. In certain situations
5054 (e.g. on Linux with Async I/O), USR1 is used for other
5055 purposes, so -k rotate uses another signal. It is best to get
5056 in the habit of using 'squid -k rotate' instead of 'kill -USR1
5063 DEFAULT: @DEFAULT_MIME_TABLE@
5064 LOC: Config.mimeTablePathname
5066 Path to Squid's icon configuration file.
5068 You shouldn't need to change this, but the default file contains
5069 examples and formatting information if you do.
5075 LOC: Config.onoff.log_mime_hdrs
5078 The Cache can record both the request and the response MIME
5079 headers for each HTTP transaction. The headers are encoded
5080 safely and will appear as two bracketed fields at the end of
5081 the access log (for either the native or httpd-emulated log
5082 formats). To enable this logging set log_mime_hdrs to 'on'.
5087 DEFAULT: @DEFAULT_PID_FILE@
5088 LOC: Config.pidFilename
5090 A filename to write the process-id to. To disable, enter "none".
5093 NAME: client_netmask
5095 LOC: Config.Addrs.client_netmask
5097 DEFAULT_DOC: Log full client IP address
5099 A netmask for client addresses in logfiles and cachemgr output.
5100 Change this to protect the privacy of your cache clients.
5101 A netmask of 255.255.255.0 will log all IP's in that range with
5102 the last digit set to '0'.
5105 NAME: strip_query_terms
5107 LOC: Config.onoff.strip_query_terms
5110 By default, Squid strips query terms from requested URLs before
5111 logging. This protects your user's privacy and reduces log size.
5113 When investigating HIT/MISS or other caching behaviour you
5114 will need to disable this to see the full URL used by Squid.
5121 LOC: Config.onoff.buffered_logs
5123 Whether to write/send access_log records ASAP or accumulate them and
5124 then write/send them in larger chunks. Buffering may improve
5125 performance because it decreases the number of I/Os. However,
5126 buffering increases the delay before log records become available to
5127 the final recipient (e.g., a disk file or logging daemon) and,
5128 hence, increases the risk of log records loss.
5130 Note that even when buffered_logs are off, Squid may have to buffer
5131 records if it cannot write/send them immediately due to pending I/Os
5132 (e.g., the I/O writing the previous log record) or connectivity loss.
5134 Currently honored by 'daemon' and 'tcp' access_log modules only.
5137 NAME: netdb_filename
5139 DEFAULT: stdio:@DEFAULT_NETDB_FILE@
5140 LOC: Config.netdbFilename
5143 Where Squid stores it's netdb journal.
5144 When enabled this journal preserves netdb state between restarts.
5146 To disable, enter "none".
5150 OPTIONS FOR TROUBLESHOOTING
5151 -----------------------------------------------------------------------------
5156 DEFAULT_IF_NONE: @DEFAULT_CACHE_LOG@
5157 LOC: Debug::cache_log
5159 Squid administrative logging file.
5161 This is where general information about Squid behavior goes. You can
5162 increase the amount of data logged to this file and how often it is
5163 rotated with "debug_options"
5169 DEFAULT_DOC: Log all critical and important messages.
5170 LOC: Debug::debugOptions
5172 Logging options are set as section,level where each source file
5173 is assigned a unique section. Lower levels result in less
5174 output, Full debugging (level 9) can result in a very large
5175 log file, so be careful.
5177 The magic word "ALL" sets debugging levels for all sections.
5178 The default is to run with "ALL,1" to record important warnings.
5180 The rotate=N option can be used to keep more or less of these logs
5181 than would otherwise be kept by logfile_rotate.
5182 For most uses a single log should be enough to monitor current
5183 events affecting Squid.
5188 LOC: Config.coredump_dir
5189 DEFAULT_IF_NONE: none
5190 DEFAULT_DOC: Use the directory from where Squid was started.
5192 By default Squid leaves core files in the directory from where
5193 it was started. If you set 'coredump_dir' to a directory
5194 that exists, Squid will chdir() to that directory at startup
5195 and coredump files will be left there.
5199 # Leave coredumps in the first cache dir
5200 coredump_dir @DEFAULT_SWAP_DIR@
5206 OPTIONS FOR FTP GATEWAYING
5207 -----------------------------------------------------------------------------
5213 LOC: Config.Ftp.anon_user
5215 If you want the anonymous login password to be more informative
5216 (and enable the use of picky FTP servers), set this to something
5217 reasonable for your domain, like wwwuser@somewhere.net
5219 The reason why this is domainless by default is the
5220 request can be made on the behalf of a user in any domain,
5221 depending on how the cache is used.
5222 Some FTP server also validate the email address is valid
5223 (for example perl.com).
5229 LOC: Config.Ftp.passive
5231 If your firewall does not allow Squid to use passive
5232 connections, turn off this option.
5234 Use of ftp_epsv_all option requires this to be ON.
5240 LOC: Config.Ftp.epsv_all
5242 FTP Protocol extensions permit the use of a special "EPSV ALL" command.
5244 NATs may be able to put the connection on a "fast path" through the
5245 translator, as the EPRT command will never be used and therefore,
5246 translation of the data portion of the segments will never be needed.
5248 When a client only expects to do two-way FTP transfers this may be
5250 If squid finds that it must do a three-way FTP transfer after issuing
5251 an EPSV ALL command, the FTP session will fail.
5253 If you have any doubts about this option do not use it.
5254 Squid will nicely attempt all other connection methods.
5256 Requires ftp_passive to be ON (default) for any effect.
5262 LOC: Config.accessList.ftp_epsv
5264 FTP Protocol extensions permit the use of a special "EPSV" command.
5266 NATs may be able to put the connection on a "fast path" through the
5267 translator using EPSV, as the EPRT command will never be used
5268 and therefore, translation of the data portion of the segments
5269 will never be needed.
5271 EPSV is often required to interoperate with FTP servers on IPv6
5272 networks. On the other hand, it may break some IPv4 servers.
5274 By default, EPSV may try EPSV with any FTP server. To fine tune
5275 that decision, you may restrict EPSV to certain clients or servers
5278 ftp_epsv allow|deny al1 acl2 ...
5280 WARNING: Disabling EPSV may cause problems with external NAT and IPv6.
5282 Only fast ACLs are supported.
5283 Requires ftp_passive to be ON (default) for any effect.
5289 LOC: Config.Ftp.eprt
5291 FTP Protocol extensions permit the use of a special "EPRT" command.
5293 This extension provides a protocol neutral alternative to the
5294 IPv4-only PORT command. When supported it enables active FTP data
5295 channels over IPv6 and efficient NAT handling.
5297 Turning this OFF will prevent EPRT being attempted and will skip
5298 straight to using PORT for IPv4 servers.
5300 Some devices are known to not handle this extension correctly and
5301 may result in crashes. Devices which suport EPRT enough to fail
5302 cleanly will result in Squid attempting PORT anyway. This directive
5303 should only be disabled when EPRT results in device failures.
5305 WARNING: Doing so will convert Squid back to the old behavior with all
5306 the related problems with external NAT devices/layers and IPv4-only FTP.
5309 NAME: ftp_sanitycheck
5312 LOC: Config.Ftp.sanitycheck
5314 For security and data integrity reasons Squid by default performs
5315 sanity checks of the addresses of FTP data connections ensure the
5316 data connection is to the requested server. If you need to allow
5317 FTP connections to servers using another IP address for the data
5318 connection turn this off.
5321 NAME: ftp_telnet_protocol
5324 LOC: Config.Ftp.telnet
5326 The FTP protocol is officially defined to use the telnet protocol
5327 as transport channel for the control connection. However, many
5328 implementations are broken and does not respect this aspect of
5331 If you have trouble accessing files with ASCII code 255 in the
5332 path or similar problems involving this ASCII code you can
5333 try setting this directive to off. If that helps, report to the
5334 operator of the FTP server in question that their FTP server
5335 is broken and does not follow the FTP standard.
5339 OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
5340 -----------------------------------------------------------------------------
5345 DEFAULT: @DEFAULT_DISKD@
5346 LOC: Config.Program.diskd
5348 Specify the location of the diskd executable.
5349 Note this is only useful if you have compiled in
5350 diskd as one of the store io modules.
5353 NAME: unlinkd_program
5356 DEFAULT: @DEFAULT_UNLINKD@
5357 LOC: Config.Program.unlinkd
5359 Specify the location of the executable for file deletion process.
5362 NAME: pinger_program
5365 DEFAULT: @DEFAULT_PINGER@
5368 Specify the location of the executable for the pinger process.
5377 Control whether the pinger is active at run-time.
5378 Enables turning ICMP pinger on and off with a simple
5379 squid -k reconfigure.
5384 OPTIONS FOR URL REWRITING
5385 -----------------------------------------------------------------------------
5388 NAME: url_rewrite_program redirect_program
5390 LOC: Config.Program.redirect
5393 Specify the location of the executable URL rewriter to use.
5394 Since they can perform almost any function there isn't one included.
5396 For each requested URL, the rewriter will receive on line with the format
5398 [channel-ID <SP>] URL [<SP> extras]<NL>
5400 See url_rewrite_extras on how to send "extras" with optional values to
5402 After processing the request the helper must reply using the following format:
5404 [channel-ID <SP>] result [<SP> kv-pairs]
5406 The result code can be:
5408 OK status=30N url="..."
5409 Redirect the URL to the one supplied in 'url='.
5410 'status=' is optional and contains the status code to send
5411 the client in Squids HTTP response. It must be one of the
5412 HTTP redirect status codes: 301, 302, 303, 307, 308.
5413 When no status is given Squid will use 302.
5415 OK rewrite-url="..."
5416 Rewrite the URL to the one supplied in 'rewrite-url='.
5417 The new URL is fetched directly by Squid and returned to
5418 the client as the response to its request.
5421 When neither of url= and rewrite-url= are sent Squid does
5425 Do not change the URL.
5428 An internal error occurred in the helper, preventing
5429 a result being identified. The 'message=' key name is
5430 reserved for delivering a log message.
5433 In addition to the above kv-pairs Squid also understands the following
5434 optional kv-pairs received from URL rewriters:
5436 Associates a TAG with the client TCP connection.
5437 The TAG is treated as a regular annotation but persists across
5438 future requests on the client connection rather than just the
5439 current request. A helper may update the TAG during subsequent
5440 requests be returning a new kv-pair.
5442 When using the concurrency= option the protocol is changed by
5443 introducing a query channel tag in front of the request/response.
5444 The query channel tag is a number between 0 and concurrency-1.
5445 This value must be echoed back unchanged to Squid as the first part
5446 of the response relating to its request.
5448 WARNING: URL re-writing ability should be avoided whenever possible.
5449 Use the URL redirect form of response instead.
5451 Re-write creates a difference in the state held by the client
5452 and server. Possibly causing confusion when the server response
5453 contains snippets of its view state. Embeded URLs, response
5454 and content Location headers, etc. are not re-written by this
5457 By default, a URL rewriter is not used.
5460 NAME: url_rewrite_children redirect_children
5461 TYPE: HelperChildConfig
5462 DEFAULT: 20 startup=0 idle=1 concurrency=0
5463 LOC: Config.redirectChildren
5465 The maximum number of redirector processes to spawn. If you limit
5466 it too few Squid will have to wait for them to process a backlog of
5467 URLs, slowing it down. If you allow too many they will use RAM
5468 and other system resources noticably.
5470 The startup= and idle= options allow some measure of skew in your
5475 Sets a minimum of how many processes are to be spawned when Squid
5476 starts or reconfigures. When set to zero the first request will
5477 cause spawning of the first child process to handle it.
5479 Starting too few will cause an initial slowdown in traffic as Squid
5480 attempts to simultaneously spawn enough processes to cope.
5484 Sets a minimum of how many processes Squid is to try and keep available
5485 at all times. When traffic begins to rise above what the existing
5486 processes can handle this many more will be spawned up to the maximum
5487 configured. A minimum setting of 1 is required.
5491 The number of requests each redirector helper can handle in
5492 parallel. Defaults to 0 which indicates the redirector
5493 is a old-style single threaded redirector.
5495 When this directive is set to a value >= 1 then the protocol
5496 used to communicate with the helper is modified to include
5497 an ID in front of the request/response. The ID from the request
5498 must be echoed back with the response to that request.
5502 Sets the maximum number of queued requests to N. The default maximum
5503 is 2*numberofchildren. If the queued requests exceed queue size and
5504 redirector_bypass configuration option is set, then redirector is bypassed.
5505 Otherwise, Squid is allowed to temporarily exceed the configured maximum,
5506 marking the affected helper as "overloaded". If the helper overload lasts
5507 more than 3 minutes, the action prescribed by the on-persistent-overload
5510 on-persistent-overload=action
5512 Specifies Squid reaction to a new helper request arriving when the helper
5513 has been overloaded for more that 3 minutes already. The number of queued
5514 requests determines whether the helper is overloaded (see the queue-size
5517 Two actions are supported:
5519 die Squid worker quits. This is the default behavior.
5521 ERR Squid treats the helper request as if it was
5522 immediately submitted, and the helper immediately
5523 replied with an ERR response. This action has no effect
5524 on the already queued and in-progress helper requests.
5527 NAME: url_rewrite_host_header redirect_rewrites_host_header
5530 LOC: Config.onoff.redir_rewrites_host
5532 To preserve same-origin security policies in browsers and
5533 prevent Host: header forgery by redirectors Squid rewrites
5534 any Host: header in redirected requests.
5536 If you are running an accelerator this may not be a wanted
5537 effect of a redirector. This directive enables you disable
5538 Host: alteration in reverse-proxy traffic.
5540 WARNING: Entries are cached on the result of the URL rewriting
5541 process, so be careful if you have domain-virtual hosts.
5543 WARNING: Squid and other software verifies the URL and Host
5544 are matching, so be careful not to relay through other proxies
5545 or inspecting firewalls with this disabled.
5548 NAME: url_rewrite_access redirector_access
5551 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
5552 LOC: Config.accessList.redirector
5554 If defined, this access list specifies which requests are
5555 sent to the redirector processes.
5557 This clause supports both fast and slow acl types.
5558 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5561 NAME: url_rewrite_bypass redirector_bypass
5563 LOC: Config.onoff.redirector_bypass
5566 When this is 'on', a request will not go through the
5567 redirector if all the helpers are busy. If this is 'off' and the
5568 redirector queue grows too large, the action is prescribed by the
5569 on-persistent-overload option. You should only enable this if the
5570 redirectors are not critical to your caching system. If you use
5571 redirectors for access control, and you enable this option,
5572 users may have access to pages they should not
5573 be allowed to request.
5574 This options sets default queue-size option of the url_rewrite_children
5578 NAME: url_rewrite_extras
5579 TYPE: TokenOrQuotedString
5580 LOC: Config.redirector_extras
5581 DEFAULT: "%>a/%>A %un %>rm myip=%la myport=%lp"
5583 Specifies a string to be append to request line format for the
5584 rewriter helper. "Quoted" format values may contain spaces and
5585 logformat %macros. In theory, any logformat %macro can be used.
5586 In practice, a %macro expands as a dash (-) if the helper request is
5587 sent before the required macro information is available to Squid.
5590 NAME: url_rewrite_timeout
5591 TYPE: UrlHelperTimeout
5592 LOC: Config.onUrlRewriteTimeout
5594 DEFAULT_DOC: Squid waits for the helper response forever
5596 Squid times active requests to redirector. The timeout value and Squid
5597 reaction to a timed out request are configurable using the following
5600 url_rewrite_timeout timeout time-units on_timeout=<action> [response=<quoted-response>]
5602 supported timeout actions:
5603 fail Squid return a ERR_GATEWAY_FAILURE error page
5605 bypass Do not re-write the URL
5607 retry Send the lookup to the helper again
5609 use_configured_response
5610 Use the <quoted-response> as helper response
5614 OPTIONS FOR STORE ID
5615 -----------------------------------------------------------------------------
5618 NAME: store_id_program storeurl_rewrite_program
5620 LOC: Config.Program.store_id
5623 Specify the location of the executable StoreID helper to use.
5624 Since they can perform almost any function there isn't one included.
5626 For each requested URL, the helper will receive one line with the format
5628 [channel-ID <SP>] URL [<SP> extras]<NL>
5631 After processing the request the helper must reply using the following format:
5633 [channel-ID <SP>] result [<SP> kv-pairs]
5635 The result code can be:
5638 Use the StoreID supplied in 'store-id='.
5641 The default is to use HTTP request URL as the store ID.
5644 An internal error occurred in the helper, preventing
5645 a result being identified.
5647 In addition to the above kv-pairs Squid also understands the following
5648 optional kv-pairs received from URL rewriters:
5650 Associates a TAG with the client TCP connection.
5651 Please see url_rewrite_program related documentation for this
5654 Helper programs should be prepared to receive and possibly ignore
5655 additional whitespace-separated tokens on each input line.
5657 When using the concurrency= option the protocol is changed by
5658 introducing a query channel tag in front of the request/response.
5659 The query channel tag is a number between 0 and concurrency-1.
5660 This value must be echoed back unchanged to Squid as the first part
5661 of the response relating to its request.
5663 NOTE: when using StoreID refresh_pattern will apply to the StoreID
5664 returned from the helper and not the URL.
5666 WARNING: Wrong StoreID value returned by a careless helper may result
5667 in the wrong cached response returned to the user.
5669 By default, a StoreID helper is not used.
5672 NAME: store_id_extras
5673 TYPE: TokenOrQuotedString
5674 LOC: Config.storeId_extras
5675 DEFAULT: "%>a/%>A %un %>rm myip=%la myport=%lp"
5677 Specifies a string to be append to request line format for the
5678 StoreId helper. "Quoted" format values may contain spaces and
5679 logformat %macros. In theory, any logformat %macro can be used.
5680 In practice, a %macro expands as a dash (-) if the helper request is
5681 sent before the required macro information is available to Squid.
5684 NAME: store_id_children storeurl_rewrite_children
5685 TYPE: HelperChildConfig
5686 DEFAULT: 20 startup=0 idle=1 concurrency=0
5687 LOC: Config.storeIdChildren
5689 The maximum number of StoreID helper processes to spawn. If you limit
5690 it too few Squid will have to wait for them to process a backlog of
5691 requests, slowing it down. If you allow too many they will use RAM
5692 and other system resources noticably.
5694 The startup= and idle= options allow some measure of skew in your
5699 Sets a minimum of how many processes are to be spawned when Squid
5700 starts or reconfigures. When set to zero the first request will
5701 cause spawning of the first child process to handle it.
5703 Starting too few will cause an initial slowdown in traffic as Squid
5704 attempts to simultaneously spawn enough processes to cope.
5708 Sets a minimum of how many processes Squid is to try and keep available
5709 at all times. When traffic begins to rise above what the existing
5710 processes can handle this many more will be spawned up to the maximum
5711 configured. A minimum setting of 1 is required.
5715 The number of requests each storeID helper can handle in
5716 parallel. Defaults to 0 which indicates the helper
5717 is a old-style single threaded program.
5719 When this directive is set to a value >= 1 then the protocol
5720 used to communicate with the helper is modified to include
5721 an ID in front of the request/response. The ID from the request
5722 must be echoed back with the response to that request.
5726 Sets the maximum number of queued requests to N. The default maximum
5727 is 2*numberofchildren. If the queued requests exceed queue size and
5728 redirector_bypass configuration option is set, then redirector is bypassed.
5729 Otherwise, Squid is allowed to temporarily exceed the configured maximum,
5730 marking the affected helper as "overloaded". If the helper overload lasts
5731 more than 3 minutes, the action prescribed by the on-persistent-overload
5734 on-persistent-overload=action
5736 Specifies Squid reaction to a new helper request arriving when the helper
5737 has been overloaded for more that 3 minutes already. The number of queued
5738 requests determines whether the helper is overloaded (see the queue-size
5741 Two actions are supported:
5743 die Squid worker quits. This is the default behavior.
5745 ERR Squid treats the helper request as if it was
5746 immediately submitted, and the helper immediately
5747 replied with an ERR response. This action has no effect
5748 on the already queued and in-progress helper requests.
5751 NAME: store_id_access storeurl_rewrite_access
5754 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
5755 LOC: Config.accessList.store_id
5757 If defined, this access list specifies which requests are
5758 sent to the StoreID processes. By default all requests
5761 This clause supports both fast and slow acl types.
5762 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5765 NAME: store_id_bypass storeurl_rewrite_bypass
5767 LOC: Config.onoff.store_id_bypass
5770 When this is 'on', a request will not go through the
5771 helper if all helpers are busy. If this is 'off' and the helper
5772 queue grows too large, the action is prescribed by the
5773 on-persistent-overload option. You should only enable this if the
5774 helpers are not critical to your caching system. If you use
5775 helpers for critical caching components, and you enable this
5776 option, users may not get objects from cache.
5777 This options sets default queue-size option of the store_id_children
5782 OPTIONS FOR TUNING THE CACHE
5783 -----------------------------------------------------------------------------
5786 NAME: cache no_cache
5789 DEFAULT_DOC: By default, this directive is unused and has no effect.
5790 LOC: Config.accessList.noCache
5792 Requests denied by this directive will not be served from the cache
5793 and their responses will not be stored in the cache. This directive
5794 has no effect on other transactions and on already cached responses.
5796 This clause supports both fast and slow acl types.
5797 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5799 This and the two other similar caching directives listed below are
5800 checked at different transaction processing stages, have different
5801 access to response information, affect different cache operations,
5802 and differ in slow ACLs support:
5804 * cache: Checked before Squid makes a hit/miss determination.
5805 No access to reply information!
5806 Denies both serving a hit and storing a miss.
5807 Supports both fast and slow ACLs.
5808 * send_hit: Checked after a hit was detected.
5809 Has access to reply (hit) information.
5810 Denies serving a hit only.
5811 Supports fast ACLs only.
5812 * store_miss: Checked before storing a cachable miss.
5813 Has access to reply (miss) information.
5814 Denies storing a miss only.
5815 Supports fast ACLs only.
5817 If you are not sure which of the three directives to use, apply the
5818 following decision logic:
5820 * If your ACL(s) are of slow type _and_ need response info, redesign.
5821 Squid does not support that particular combination at this time.
5823 * If your directive ACL(s) are of slow type, use "cache"; and/or
5824 * if your directive ACL(s) need no response info, use "cache".
5826 * If you do not want the response cached, use store_miss; and/or
5827 * if you do not want a hit on a cached response, use send_hit.
5833 DEFAULT_DOC: By default, this directive is unused and has no effect.
5834 LOC: Config.accessList.sendHit
5836 Responses denied by this directive will not be served from the cache
5837 (but may still be cached, see store_miss). This directive has no
5838 effect on the responses it allows and on the cached objects.
5840 Please see the "cache" directive for a summary of differences among
5841 store_miss, send_hit, and cache directives.
5843 Unlike the "cache" directive, send_hit only supports fast acl
5844 types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5848 # apply custom Store ID mapping to some URLs
5849 acl MapMe dstdomain .c.example.com
5850 store_id_program ...
5851 store_id_access allow MapMe
5853 # but prevent caching of special responses
5854 # such as 302 redirects that cause StoreID loops
5855 acl Ordinary http_status 200-299
5856 store_miss deny MapMe !Ordinary
5858 # and do not serve any previously stored special responses
5859 # from the cache (in case they were already cached before
5860 # the above store_miss rule was in effect).
5861 send_hit deny MapMe !Ordinary
5867 DEFAULT_DOC: By default, this directive is unused and has no effect.
5868 LOC: Config.accessList.storeMiss
5870 Responses denied by this directive will not be cached (but may still
5871 be served from the cache, see send_hit). This directive has no
5872 effect on the responses it allows and on the already cached responses.
5874 Please see the "cache" directive for a summary of differences among
5875 store_miss, send_hit, and cache directives. See the
5876 send_hit directive for a usage example.
5878 Unlike the "cache" directive, store_miss only supports fast acl
5879 types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5885 LOC: Config.maxStale
5888 This option puts an upper limit on how stale content Squid
5889 will serve from the cache if cache validation fails.
5890 Can be overriden by the refresh_pattern max-stale option.
5893 NAME: refresh_pattern
5894 TYPE: refreshpattern
5898 usage: refresh_pattern [-i] regex min percent max [options]
5900 By default, regular expressions are CASE-SENSITIVE. To make
5901 them case-insensitive, use the -i option.
5903 'Min' is the time (in minutes) an object without an explicit
5904 expiry time should be considered fresh. The recommended
5905 value is 0, any higher values may cause dynamic applications
5906 to be erroneously cached unless the application designer
5907 has taken the appropriate actions.
5909 'Percent' is a percentage of the objects age (time since last
5910 modification age) an object without explicit expiry time
5911 will be considered fresh.
5913 'Max' is an upper limit on how long objects without an explicit
5914 expiry time will be considered fresh. The value is also used
5915 to form Cache-Control: max-age header for a request sent from
5916 Squid to origin/parent.
5918 options: override-expire
5928 override-expire enforces min age even if the server
5929 sent an explicit expiry time (e.g., with the
5930 Expires: header or Cache-Control: max-age). Doing this
5931 VIOLATES the HTTP standard. Enabling this feature
5932 could make you liable for problems which it causes.
5934 Note: override-expire does not enforce staleness - it only extends
5935 freshness / min. If the server returns a Expires time which
5936 is longer than your max time, Squid will still consider
5937 the object fresh for that period of time.
5939 override-lastmod enforces min age even on objects
5940 that were modified recently.
5942 reload-into-ims changes a client no-cache or ``reload''
5943 request for a cached entry into a conditional request using
5944 If-Modified-Since and/or If-None-Match headers, provided the
5945 cached entry has a Last-Modified and/or a strong ETag header.
5946 Doing this VIOLATES the HTTP standard. Enabling this feature
5947 could make you liable for problems which it causes.
5949 ignore-reload ignores a client no-cache or ``reload''
5950 header. Doing this VIOLATES the HTTP standard. Enabling
5951 this feature could make you liable for problems which
5954 ignore-no-store ignores any ``Cache-control: no-store''
5955 headers received from a server. Doing this VIOLATES
5956 the HTTP standard. Enabling this feature could make you
5957 liable for problems which it causes.
5959 ignore-private ignores any ``Cache-control: private''
5960 headers received from a server. Doing this VIOLATES
5961 the HTTP standard. Enabling this feature could make you
5962 liable for problems which it causes.
5964 refresh-ims causes squid to contact the origin server
5965 when a client issues an If-Modified-Since request. This
5966 ensures that the client will receive an updated version
5967 if one is available.
5969 store-stale stores responses even if they don't have explicit
5970 freshness or a validator (i.e., Last-Modified or an ETag)
5971 present, or if they're already stale. By default, Squid will
5972 not cache such responses because they usually can't be
5973 reused. Note that such responses will be stale by default.
5975 max-stale=NN provide a maximum staleness factor. Squid won't
5976 serve objects more stale than this even if it failed to
5977 validate the object. Default: use the max_stale global limit.
5979 Basically a cached object is:
5981 FRESH if expire > now, else STALE
5983 FRESH if lm-factor < percent, else STALE
5987 The refresh_pattern lines are checked in the order listed here.
5988 The first entry which matches is used. If none of the entries
5989 match the default will be used.
5991 Note, you must uncomment all the default lines if you want
5992 to change one. The default setting is only active if none is
5998 # Add any of your own refresh_pattern entries above these.
6000 refresh_pattern ^ftp: 1440 20% 10080
6001 refresh_pattern ^gopher: 1440 0% 1440
6002 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0
6003 refresh_pattern . 0 20% 4320
6007 NAME: quick_abort_min
6011 LOC: Config.quickAbort.min
6014 NAME: quick_abort_max
6018 LOC: Config.quickAbort.max
6021 NAME: quick_abort_pct
6025 LOC: Config.quickAbort.pct
6027 The cache by default continues downloading aborted requests
6028 which are almost completed (less than 16 KB remaining). This
6029 may be undesirable on slow (e.g. SLIP) links and/or very busy
6030 caches. Impatient users may tie up file descriptors and
6031 bandwidth by repeatedly requesting and immediately aborting
6034 When the user aborts a request, Squid will check the
6035 quick_abort values to the amount of data transferred until
6038 If the transfer has less than 'quick_abort_min' KB remaining,
6039 it will finish the retrieval.
6041 If the transfer has more than 'quick_abort_max' KB remaining,
6042 it will abort the retrieval.
6044 If more than 'quick_abort_pct' of the transfer has completed,
6045 it will finish the retrieval.
6047 If you do not want any retrieval to continue after the client
6048 has aborted, set both 'quick_abort_min' and 'quick_abort_max'
6051 If you want retrievals to always continue if they are being
6052 cached set 'quick_abort_min' to '-1 KB'.
6055 NAME: read_ahead_gap
6056 COMMENT: buffer-size
6058 LOC: Config.readAheadGap
6061 The amount of data the cache will buffer ahead of what has been
6062 sent to the client when retrieving an object from another server.
6066 IFDEF: USE_HTTP_VIOLATIONS
6069 LOC: Config.negativeTtl
6072 Set the Default Time-to-Live (TTL) for failed requests.
6073 Certain types of failures (such as "connection refused" and
6074 "404 Not Found") are able to be negatively-cached for a short time.
6075 Modern web servers should provide Expires: header, however if they
6076 do not this can provide a minimum TTL.
6077 The default is not to cache errors with unknown expiry details.
6079 Note that this is different from negative caching of DNS lookups.
6081 WARNING: Doing this VIOLATES the HTTP standard. Enabling
6082 this feature could make you liable for problems which it
6086 NAME: positive_dns_ttl
6089 LOC: Config.positiveDnsTtl
6092 Upper limit on how long Squid will cache positive DNS responses.
6093 Default is 6 hours (360 minutes). This directive must be set
6094 larger than negative_dns_ttl.
6097 NAME: negative_dns_ttl
6100 LOC: Config.negativeDnsTtl
6103 Time-to-Live (TTL) for negative caching of failed DNS lookups.
6104 This also sets the lower cache limit on positive lookups.
6105 Minimum value is 1 second, and it is not recommendable to go
6106 much below 10 seconds.
6109 NAME: range_offset_limit
6110 COMMENT: size [acl acl...]
6112 LOC: Config.rangeOffsetLimit
6115 usage: (size) [units] [[!]aclname]
6117 Sets an upper limit on how far (number of bytes) into the file
6118 a Range request may be to cause Squid to prefetch the whole file.
6119 If beyond this limit, Squid forwards the Range request as it is and
6120 the result is NOT cached.
6122 This is to stop a far ahead range request (lets say start at 17MB)
6123 from making Squid fetch the whole object up to that point before
6124 sending anything to the client.
6126 Multiple range_offset_limit lines may be specified, and they will
6127 be searched from top to bottom on each request until a match is found.
6128 The first match found will be used. If no line matches a request, the
6129 default limit of 0 bytes will be used.
6131 'size' is the limit specified as a number of units.
6133 'units' specifies whether to use bytes, KB, MB, etc.
6134 If no units are specified bytes are assumed.
6136 A size of 0 causes Squid to never fetch more than the
6137 client requested. (default)
6139 A size of 'none' causes Squid to always fetch the object from the
6140 beginning so it may cache the result. (2.0 style)
6142 'aclname' is the name of a defined ACL.
6144 NP: Using 'none' as the byte value here will override any quick_abort settings
6145 that may otherwise apply to the range request. The range request will
6146 be fully fetched from start to finish regardless of the client
6147 actions. This affects bandwidth usage.
6150 NAME: minimum_expiry_time
6153 LOC: Config.minimum_expiry_time
6156 The minimum caching time according to (Expires - Date)
6157 headers Squid honors if the object can't be revalidated.
6158 The default is 60 seconds.
6160 In reverse proxy environments it might be desirable to honor
6161 shorter object lifetimes. It is most likely better to make
6162 your server return a meaningful Last-Modified header however.
6164 In ESI environments where page fragments often have short
6165 lifetimes, this will often be best set to 0.
6168 NAME: store_avg_object_size
6172 LOC: Config.Store.avgObjectSize
6174 Average object size, used to estimate number of objects your
6175 cache can hold. The default is 13 KB.
6177 This is used to pre-seed the cache index memory allocation to
6178 reduce expensive reallocate operations while handling clients
6179 traffic. Too-large values may result in memory allocation during
6180 peak traffic, too-small values will result in wasted memory.
6182 Check the cache manager 'info' report metrics for the real
6183 object sizes seen by your Squid before tuning this.
6186 NAME: store_objects_per_bucket
6189 LOC: Config.Store.objectsPerBucket
6191 Target number of objects per bucket in the store hash table.
6192 Lowering this value increases the total number of buckets and
6193 also the storage maintenance rate. The default is 20.
6198 -----------------------------------------------------------------------------
6201 NAME: request_header_max_size
6205 LOC: Config.maxRequestHeaderSize
6207 This specifies the maximum size for HTTP headers in a request.
6208 Request headers are usually relatively small (about 512 bytes).
6209 Placing a limit on the request header size will catch certain
6210 bugs (for example with persistent connections) and possibly
6211 buffer-overflow or denial-of-service attacks.
6214 NAME: reply_header_max_size
6218 LOC: Config.maxReplyHeaderSize
6220 This specifies the maximum size for HTTP headers in a reply.
6221 Reply headers are usually relatively small (about 512 bytes).
6222 Placing a limit on the reply header size will catch certain
6223 bugs (for example with persistent connections) and possibly
6224 buffer-overflow or denial-of-service attacks.
6227 NAME: request_body_max_size
6231 DEFAULT_DOC: No limit.
6232 LOC: Config.maxRequestBodySize
6234 This specifies the maximum size for an HTTP request body.
6235 In other words, the maximum size of a PUT/POST request.
6236 A user who attempts to send a request with a body larger
6237 than this limit receives an "Invalid Request" error message.
6238 If you set this parameter to a zero (the default), there will
6239 be no limit imposed.
6241 See also client_request_buffer_max_size for an alternative
6242 limitation on client uploads which can be configured.
6245 NAME: client_request_buffer_max_size
6249 LOC: Config.maxRequestBufferSize
6251 This specifies the maximum buffer size of a client request.
6252 It prevents squid eating too much memory when somebody uploads
6257 IFDEF: USE_HTTP_VIOLATIONS
6260 DEFAULT_DOC: Obey RFC 2616.
6261 LOC: Config.accessList.brokenPosts
6263 A list of ACL elements which, if matched, causes Squid to send
6264 an extra CRLF pair after the body of a PUT/POST request.
6266 Some HTTP servers has broken implementations of PUT/POST,
6267 and rely on an extra CRLF pair sent by some WWW clients.
6269 Quote from RFC2616 section 4.1 on this matter:
6271 Note: certain buggy HTTP/1.0 client implementations generate an
6272 extra CRLF's after a POST request. To restate what is explicitly
6273 forbidden by the BNF, an HTTP/1.1 client must not preface or follow
6274 a request with an extra CRLF.
6276 This clause only supports fast acl types.
6277 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6280 acl buggy_server url_regex ^http://....
6281 broken_posts allow buggy_server
6284 NAME: adaptation_uses_indirect_client icap_uses_indirect_client
6287 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_ADAPTATION
6289 LOC: Adaptation::Config::use_indirect_client
6291 Controls whether the indirect client IP address (instead of the direct
6292 client IP address) is passed to adaptation services.
6294 See also: follow_x_forwarded_for adaptation_send_client_ip
6298 IFDEF: USE_HTTP_VIOLATIONS
6302 LOC: Config.onoff.via
6304 If set (default), Squid will include a Via header in requests and
6305 replies as required by RFC2616.
6308 NAME: vary_ignore_expire
6311 LOC: Config.onoff.vary_ignore_expire
6314 Many HTTP servers supporting Vary gives such objects
6315 immediate expiry time with no cache-control header
6316 when requested by a HTTP/1.0 client. This option
6317 enables Squid to ignore such expiry times until
6318 HTTP/1.1 is fully implemented.
6320 WARNING: If turned on this may eventually cause some
6321 varying objects not intended for caching to get cached.
6324 NAME: request_entities
6326 LOC: Config.onoff.request_entities
6329 Squid defaults to deny GET and HEAD requests with request entities,
6330 as the meaning of such requests are undefined in the HTTP standard
6331 even if not explicitly forbidden.
6333 Set this directive to on if you have clients which insists
6334 on sending request entities in GET or HEAD requests. But be warned
6335 that there is server software (both proxies and web servers) which
6336 can fail to properly process this kind of request which may make you
6337 vulnerable to cache pollution attacks if enabled.
6340 NAME: request_header_access
6341 IFDEF: USE_HTTP_VIOLATIONS
6342 TYPE: http_header_access
6343 LOC: Config.request_header_access
6345 DEFAULT_DOC: No limits.
6347 Usage: request_header_access header_name allow|deny [!]aclname ...
6349 WARNING: Doing this VIOLATES the HTTP standard. Enabling
6350 this feature could make you liable for problems which it
6353 This option replaces the old 'anonymize_headers' and the
6354 older 'http_anonymizer' option with something that is much
6355 more configurable. A list of ACLs for each header name allows
6356 removal of specific header fields under specific conditions.
6358 This option only applies to outgoing HTTP request headers (i.e.,
6359 headers sent by Squid to the next HTTP hop such as a cache peer
6360 or an origin server). The option has no effect during cache hit
6361 detection. The equivalent adaptation vectoring point in ICAP
6362 terminology is post-cache REQMOD.
6364 The option is applied to individual outgoing request header
6365 fields. For each request header field F, Squid uses the first
6366 qualifying sets of request_header_access rules:
6368 1. Rules with header_name equal to F's name.
6369 2. Rules with header_name 'Other', provided F's name is not
6370 on the hard-coded list of commonly used HTTP header names.
6371 3. Rules with header_name 'All'.
6373 Within that qualifying rule set, rule ACLs are checked as usual.
6374 If ACLs of an "allow" rule match, the header field is allowed to
6375 go through as is. If ACLs of a "deny" rule match, the header is
6376 removed and request_header_replace is then checked to identify
6377 if the removed header has a replacement. If no rules within the
6378 set have matching ACLs, the header field is left as is.
6380 For example, to achieve the same behavior as the old
6381 'http_anonymizer standard' option, you should use:
6383 request_header_access From deny all
6384 request_header_access Referer deny all
6385 request_header_access User-Agent deny all
6387 Or, to reproduce the old 'http_anonymizer paranoid' feature
6390 request_header_access Authorization allow all
6391 request_header_access Proxy-Authorization allow all
6392 request_header_access Cache-Control allow all
6393 request_header_access Content-Length allow all
6394 request_header_access Content-Type allow all
6395 request_header_access Date allow all
6396 request_header_access Host allow all
6397 request_header_access If-Modified-Since allow all
6398 request_header_access Pragma allow all
6399 request_header_access Accept allow all
6400 request_header_access Accept-Charset allow all
6401 request_header_access Accept-Encoding allow all
6402 request_header_access Accept-Language allow all
6403 request_header_access Connection allow all
6404 request_header_access All deny all
6406 HTTP reply headers are controlled with the reply_header_access directive.
6408 By default, all headers are allowed (no anonymizing is performed).
6411 NAME: reply_header_access
6412 IFDEF: USE_HTTP_VIOLATIONS
6413 TYPE: http_header_access
6414 LOC: Config.reply_header_access
6416 DEFAULT_DOC: No limits.
6418 Usage: reply_header_access header_name allow|deny [!]aclname ...
6420 WARNING: Doing this VIOLATES the HTTP standard. Enabling
6421 this feature could make you liable for problems which it
6424 This option only applies to reply headers, i.e., from the
6425 server to the client.
6427 This is the same as request_header_access, but in the other
6428 direction. Please see request_header_access for detailed
6431 For example, to achieve the same behavior as the old
6432 'http_anonymizer standard' option, you should use:
6434 reply_header_access Server deny all
6435 reply_header_access WWW-Authenticate deny all
6436 reply_header_access Link deny all
6438 Or, to reproduce the old 'http_anonymizer paranoid' feature
6441 reply_header_access Allow allow all
6442 reply_header_access WWW-Authenticate allow all
6443 reply_header_access Proxy-Authenticate allow all
6444 reply_header_access Cache-Control allow all
6445 reply_header_access Content-Encoding allow all
6446 reply_header_access Content-Length allow all
6447 reply_header_access Content-Type allow all
6448 reply_header_access Date allow all
6449 reply_header_access Expires allow all
6450 reply_header_access Last-Modified allow all
6451 reply_header_access Location allow all
6452 reply_header_access Pragma allow all
6453 reply_header_access Content-Language allow all
6454 reply_header_access Retry-After allow all
6455 reply_header_access Title allow all
6456 reply_header_access Content-Disposition allow all
6457 reply_header_access Connection allow all
6458 reply_header_access All deny all
6460 HTTP request headers are controlled with the request_header_access directive.
6462 By default, all headers are allowed (no anonymizing is
6466 NAME: request_header_replace header_replace
6467 IFDEF: USE_HTTP_VIOLATIONS
6468 TYPE: http_header_replace
6469 LOC: Config.request_header_access
6472 Usage: request_header_replace header_name message
6473 Example: request_header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
6475 This option allows you to change the contents of headers
6476 denied with request_header_access above, by replacing them
6477 with some fixed string.
6479 This only applies to request headers, not reply headers.
6481 By default, headers are removed if denied.
6484 NAME: reply_header_replace
6485 IFDEF: USE_HTTP_VIOLATIONS
6486 TYPE: http_header_replace
6487 LOC: Config.reply_header_access
6490 Usage: reply_header_replace header_name message
6491 Example: reply_header_replace Server Foo/1.0
6493 This option allows you to change the contents of headers
6494 denied with reply_header_access above, by replacing them
6495 with some fixed string.
6497 This only applies to reply headers, not request headers.
6499 By default, headers are removed if denied.
6502 NAME: request_header_add
6503 TYPE: HeaderWithAclList
6504 LOC: Config.request_header_add
6507 Usage: request_header_add field-name field-value [ acl ... ]
6508 Example: request_header_add X-Client-CA "CA=%ssl::>cert_issuer" all
6510 This option adds header fields to outgoing HTTP requests (i.e.,
6511 request headers sent by Squid to the next HTTP hop such as a
6512 cache peer or an origin server). The option has no effect during
6513 cache hit detection. The equivalent adaptation vectoring point
6514 in ICAP terminology is post-cache REQMOD.
6516 Field-name is a token specifying an HTTP header name. If a
6517 standard HTTP header name is used, Squid does not check whether
6518 the new header conflicts with any existing headers or violates
6519 HTTP rules. If the request to be modified already contains a
6520 field with the same name, the old field is preserved but the
6521 header field values are not merged.
6523 Field-value is either a token or a quoted string. If quoted
6524 string format is used, then the surrounding quotes are removed
6525 while escape sequences and %macros are processed.
6527 One or more Squid ACLs may be specified to restrict header
6528 injection to matching requests. As always in squid.conf, all
6529 ACLs in the ACL list must be satisfied for the insertion to
6530 happen. The request_header_add supports fast ACLs only.
6532 See also: reply_header_add.
6535 NAME: reply_header_add
6536 TYPE: HeaderWithAclList
6537 LOC: Config.reply_header_add
6540 Usage: reply_header_add field-name field-value [ acl ... ]
6541 Example: reply_header_add X-Client-CA "CA=%ssl::>cert_issuer" all
6543 This option adds header fields to outgoing HTTP responses (i.e., response
6544 headers delivered by Squid to the client). This option has no effect on
6545 cache hit detection. The equivalent adaptation vectoring point in
6546 ICAP terminology is post-cache RESPMOD. This option does not apply to
6547 successful CONNECT replies.
6549 Field-name is a token specifying an HTTP header name. If a
6550 standard HTTP header name is used, Squid does not check whether
6551 the new header conflicts with any existing headers or violates
6552 HTTP rules. If the response to be modified already contains a
6553 field with the same name, the old field is preserved but the
6554 header field values are not merged.
6556 Field-value is either a token or a quoted string. If quoted
6557 string format is used, then the surrounding quotes are removed
6558 while escape sequences and %macros are processed.
6560 One or more Squid ACLs may be specified to restrict header
6561 injection to matching responses. As always in squid.conf, all
6562 ACLs in the ACL list must be satisfied for the insertion to
6563 happen. The reply_header_add option supports fast ACLs only.
6565 See also: request_header_add.
6573 This option used to log custom information about the master
6574 transaction. For example, an admin may configure Squid to log
6575 which "user group" the transaction belongs to, where "user group"
6576 will be determined based on a set of ACLs and not [just]
6577 authentication information.
6578 Values of key/value pairs can be logged using %{key}note macros:
6580 note key value acl ...
6581 logformat myFormat ... %{key}note ...
6584 NAME: relaxed_header_parser
6585 COMMENT: on|off|warn
6587 LOC: Config.onoff.relaxed_header_parser
6590 In the default "on" setting Squid accepts certain forms
6591 of non-compliant HTTP messages where it is unambiguous
6592 what the sending application intended even if the message
6593 is not correctly formatted. The messages is then normalized
6594 to the correct form when forwarded by Squid.
6596 If set to "warn" then a warning will be emitted in cache.log
6597 each time such HTTP error is encountered.
6599 If set to "off" then such HTTP errors will cause the request
6600 or response to be rejected.
6603 NAME: collapsed_forwarding
6606 LOC: Config.onoff.collapsed_forwarding
6609 This option controls whether Squid is allowed to merge multiple
6610 potentially cachable requests for the same URI before Squid knows
6611 whether the response is going to be cachable.
6613 When enabled, instead of forwarding each concurrent request for
6614 the same URL, Squid just sends the first of them. The other, so
6615 called "collapsed" requests, wait for the response to the first
6616 request and, if it happens to be cachable, use that response.
6617 Here, "concurrent requests" means "received after the first
6618 request headers were parsed and before the corresponding response
6619 headers were parsed".
6621 This feature is disabled by default: enabling collapsed
6622 forwarding needlessly delays forwarding requests that look
6623 cachable (when they are collapsed) but then need to be forwarded
6624 individually anyway because they end up being for uncachable
6625 content. However, in some cases, such as acceleration of highly
6626 cachable content with periodic or grouped expiration times, the
6627 gains from collapsing [large volumes of simultaneous refresh
6628 requests] outweigh losses from such delays.
6630 Squid collapses two kinds of requests: regular client requests
6631 received on one of the listening ports and internal "cache
6632 revalidation" requests which are triggered by those regular
6633 requests hitting a stale cached object. Revalidation collapsing
6634 is currently disabled for Squid instances containing SMP-aware
6635 disk or memory caches and for Vary-controlled cached objects.
6638 NAME: collapsed_forwarding_access
6641 DEFAULT_DOC: Requests may be collapsed if collapsed_forwarding is on.
6642 LOC: Config.accessList.collapsedForwardingAccess
6644 Use this directive to restrict collapsed forwarding to a subset of
6645 eligible requests. The directive is checked for regular HTTP
6646 requests, internal revalidation requests, and HTCP/ICP requests.
6648 collapsed_forwarding_access allow|deny [!]aclname ...
6650 This directive cannot force collapsing. It has no effect on
6651 collapsing unless collapsed_forwarding is 'on', and all other
6652 collapsing preconditions are satisfied.
6654 * A denied request will not collapse, and future transactions will
6655 not collapse on it (even if they are allowed to collapse).
6657 * An allowed request may collapse, or future transactions may
6658 collapse on it (provided they are allowed to collapse).
6660 This directive is evaluated before receiving HTTP response headers
6661 and without access to Squid-to-peer connection (if any).
6663 Only fast ACLs are supported.
6665 See also: collapsed_forwarding.
6668 NAME: collapsed_forwarding_shared_entries_limit
6669 COMMENT: (number of entries)
6671 LOC: Config.collapsed_forwarding_shared_entries_limit
6674 This limits the size of a table used for sharing information
6675 about collapsible entries among SMP workers. Limiting sharing
6676 too much results in cache content duplication and missed
6677 collapsing opportunities. Using excessively large values
6678 wastes shared memory.
6680 The limit should be significantly larger then the number of
6681 concurrent collapsible entries one wants to share. For a cache
6682 that handles less than 5000 concurrent requests, the default
6683 setting of 16384 should be plenty.
6685 If the limit is set to zero, it disables sharing of collapsed
6686 forwarding between SMP workers.
6691 -----------------------------------------------------------------------------
6694 NAME: forward_timeout
6697 LOC: Config.Timeout.forward
6700 This parameter specifies how long Squid should at most attempt in
6701 finding a forwarding path for the request before giving up.
6704 NAME: connect_timeout
6707 LOC: Config.Timeout.connect
6710 This parameter specifies how long to wait for the TCP connect to
6711 the requested server or peer to complete before Squid should
6712 attempt to find another path where to forward the request.
6715 NAME: peer_connect_timeout
6718 LOC: Config.Timeout.peer_connect
6721 This parameter specifies how long to wait for a pending TCP
6722 connection to a peer cache. The default is 30 seconds. You
6723 may also set different timeout values for individual neighbors
6724 with the 'connect-timeout' option on a 'cache_peer' line.
6730 LOC: Config.Timeout.read
6733 Applied on peer server connections.
6735 After each successful read(), the timeout will be extended by this
6736 amount. If no data is read again after this amount of time,
6737 the request is aborted and logged with ERR_READ_TIMEOUT.
6739 The default is 15 minutes.
6745 LOC: Config.Timeout.write
6748 This timeout is tracked for all connections that have data
6749 available for writing and are waiting for the socket to become
6750 ready. After each successful write, the timeout is extended by
6751 the configured amount. If Squid has data to write but the
6752 connection is not ready for the configured duration, the
6753 transaction associated with the connection is terminated. The
6754 default is 15 minutes.
6757 NAME: request_timeout
6759 LOC: Config.Timeout.request
6762 How long to wait for complete HTTP request headers after initial
6763 connection establishment.
6766 NAME: request_start_timeout
6768 LOC: Config.Timeout.request_start_timeout
6771 How long to wait for the first request byte after initial
6772 connection establishment.
6775 NAME: client_idle_pconn_timeout persistent_request_timeout
6777 LOC: Config.Timeout.clientIdlePconn
6780 How long to wait for the next HTTP request on a persistent
6781 client connection after the previous request completes.
6784 NAME: ftp_client_idle_timeout
6786 LOC: Config.Timeout.ftpClientIdle
6789 How long to wait for an FTP request on a connection to Squid ftp_port.
6790 Many FTP clients do not deal with idle connection closures well,
6791 necessitating a longer default timeout than client_idle_pconn_timeout
6792 used for incoming HTTP requests.
6795 NAME: client_lifetime
6798 LOC: Config.Timeout.lifetime
6801 The maximum amount of time a client (browser) is allowed to
6802 remain connected to the cache process. This protects the Cache
6803 from having a lot of sockets (and hence file descriptors) tied up
6804 in a CLOSE_WAIT state from remote clients that go away without
6805 properly shutting down (either because of a network failure or
6806 because of a poor client implementation). The default is one
6809 NOTE: The default value is intended to be much larger than any
6810 client would ever need to be connected to your cache. You
6811 should probably change client_lifetime only as a last resort.
6812 If you seem to have many client connections tying up
6813 filedescriptors, we recommend first tuning the read_timeout,
6814 request_timeout, persistent_request_timeout and quick_abort values.
6817 NAME: pconn_lifetime
6820 LOC: Config.Timeout.pconnLifetime
6823 Desired maximum lifetime of a persistent connection.
6824 When set, Squid will close a now-idle persistent connection that
6825 exceeded configured lifetime instead of moving the connection into
6826 the idle connection pool (or equivalent). No effect on ongoing/active
6827 transactions. Connection lifetime is the time period from the
6828 connection acceptance or opening time until "now".
6830 This limit is useful in environments with long-lived connections
6831 where Squid configuration or environmental factors change during a
6832 single connection lifetime. If unrestricted, some connections may
6833 last for hours and even days, ignoring those changes that should
6834 have affected their behavior or their existence.
6836 Currently, a new lifetime value supplied via Squid reconfiguration
6837 has no effect on already idle connections unless they become busy.
6839 When set to '0' this limit is not used.
6842 NAME: half_closed_clients
6844 LOC: Config.onoff.half_closed_clients
6847 Some clients may shutdown the sending side of their TCP
6848 connections, while leaving their receiving sides open. Sometimes,
6849 Squid can not tell the difference between a half-closed and a
6850 fully-closed TCP connection.
6852 By default, Squid will immediately close client connections when
6853 read(2) returns "no more data to read."
6855 Change this option to 'on' and Squid will keep open connections
6856 until a read(2) or write(2) on the socket returns an error.
6857 This may show some benefits for reverse proxies. But if not
6858 it is recommended to leave OFF.
6861 NAME: server_idle_pconn_timeout pconn_timeout
6863 LOC: Config.Timeout.serverIdlePconn
6866 Timeout for idle persistent connections to servers and other
6873 LOC: Ident::TheConfig.timeout
6876 Maximum time to wait for IDENT lookups to complete.
6878 If this is too high, and you enabled IDENT lookups from untrusted
6879 users, you might be susceptible to denial-of-service by having
6880 many ident requests going at once.
6883 NAME: shutdown_lifetime
6886 LOC: Config.shutdownLifetime
6889 When SIGTERM or SIGHUP is received, the cache is put into
6890 "shutdown pending" mode until all active sockets are closed.
6891 This value is the lifetime to set for all open descriptors
6892 during shutdown mode. Any active clients after this many
6893 seconds will receive a 'timeout' message.
6897 ADMINISTRATIVE PARAMETERS
6898 -----------------------------------------------------------------------------
6904 LOC: Config.adminEmail
6906 Email-address of local cache manager who will receive
6907 mail if the cache dies. The default is "webmaster".
6913 LOC: Config.EmailFrom
6915 From: email-address for mail sent when the cache dies.
6916 The default is to use 'squid@unique_hostname'.
6918 See also: unique_hostname directive.
6924 LOC: Config.EmailProgram
6926 Email program used to send mail if the cache dies.
6927 The default is "mail". The specified program must comply
6928 with the standard Unix mail syntax:
6929 mail-program recipient < mailfile
6931 Optional command line options can be specified.
6934 NAME: cache_effective_user
6936 DEFAULT: @DEFAULT_CACHE_EFFECTIVE_USER@
6937 LOC: Config.effectiveUser
6939 If you start Squid as root, it will change its effective/real
6940 UID/GID to the user specified below. The default is to change
6941 to UID of @DEFAULT_CACHE_EFFECTIVE_USER@.
6942 see also; cache_effective_group
6945 NAME: cache_effective_group
6948 DEFAULT_DOC: Use system group memberships of the cache_effective_user account
6949 LOC: Config.effectiveGroup
6951 Squid sets the GID to the effective user's default group ID
6952 (taken from the password file) and supplementary group list
6953 from the groups membership.
6955 If you want Squid to run with a specific GID regardless of
6956 the group memberships of the effective user then set this
6957 to the group (or GID) you want Squid to run as. When set
6958 all other group privileges of the effective user are ignored
6959 and only this GID is effective. If Squid is not started as
6960 root the user starting Squid MUST be member of the specified
6963 This option is not recommended by the Squid Team.
6964 Our preference is for administrators to configure a secure
6965 user account for squid with UID/GID matching system policies.
6968 NAME: httpd_suppress_version_string
6972 LOC: Config.onoff.httpd_suppress_version_string
6974 Suppress Squid version string info in HTTP headers and HTML error pages.
6977 NAME: visible_hostname
6979 LOC: Config.visibleHostname
6981 DEFAULT_DOC: Automatically detect the system host name
6983 If you want to present a special hostname in error messages, etc,
6984 define this. Otherwise, the return value of gethostname()
6985 will be used. If you have multiple caches in a cluster and
6986 get errors about IP-forwarding you must set them to have individual
6987 names with this setting.
6990 NAME: unique_hostname
6992 LOC: Config.uniqueHostname
6994 DEFAULT_DOC: Copy the value from visible_hostname
6996 If you want to have multiple machines with the same
6997 'visible_hostname' you must give each machine a different
6998 'unique_hostname' so forwarding loops can be detected.
7001 NAME: hostname_aliases
7003 LOC: Config.hostnameAliases
7006 A list of other DNS names your cache has.
7014 Minimum umask which should be enforced while the proxy
7015 is running, in addition to the umask set at startup.
7017 For a traditional octal representation of umasks, start
7022 OPTIONS FOR THE CACHE REGISTRATION SERVICE
7023 -----------------------------------------------------------------------------
7025 This section contains parameters for the (optional) cache
7026 announcement service. This service is provided to help
7027 cache administrators locate one another in order to join or
7028 create cache hierarchies.
7030 An 'announcement' message is sent (via UDP) to the registration
7031 service by Squid. By default, the announcement message is NOT
7032 SENT unless you enable it with 'announce_period' below.
7034 The announcement message includes your hostname, plus the
7035 following information from this configuration file:
7041 All current information is processed regularly and made
7042 available on the Web at http://www.ircache.net/Cache/Tracker/.
7045 NAME: announce_period
7047 LOC: Config.Announce.period
7049 DEFAULT_DOC: Announcement messages disabled.
7051 This is how frequently to send cache announcements.
7053 To enable announcing your cache, just set an announce period.
7056 announce_period 1 day
7061 DEFAULT: tracker.ircache.net
7062 LOC: Config.Announce.host
7064 Set the hostname where announce registration messages will be sent.
7066 See also announce_port and announce_file
7072 LOC: Config.Announce.file
7074 The contents of this file will be included in the announce
7075 registration messages.
7081 LOC: Config.Announce.port
7083 Set the port where announce registration messages will be sent.
7085 See also announce_host and announce_file
7089 HTTPD-ACCELERATOR OPTIONS
7090 -----------------------------------------------------------------------------
7093 NAME: httpd_accel_surrogate_id
7096 DEFAULT_DOC: visible_hostname is used if no specific ID is set.
7097 LOC: Config.Accel.surrogate_id
7099 Surrogates (http://www.esi.org/architecture_spec_1.0.html)
7100 need an identification token to allow control targeting. Because
7101 a farm of surrogates may all perform the same tasks, they may share
7102 an identification token.
7105 NAME: http_accel_surrogate_remote
7109 LOC: Config.onoff.surrogate_is_remote
7111 Remote surrogates (such as those in a CDN) honour the header
7112 "Surrogate-Control: no-store-remote".
7114 Set this to on to have squid behave as a remote surrogate.
7118 IFDEF: USE_SQUID_ESI
7119 COMMENT: libxml2|expat
7121 LOC: ESIParser::Type
7123 DEFAULT_DOC: Selects libxml2 if available at ./configure time or libexpat otherwise.
7125 Selects the XML parsing library to use when interpreting responses with
7128 To disable ESI handling completely, ./configure Squid with --disable-esi.
7132 DELAY POOL PARAMETERS
7133 -----------------------------------------------------------------------------
7137 TYPE: delay_pool_count
7139 IFDEF: USE_DELAY_POOLS
7142 This represents the number of delay pools to be used. For example,
7143 if you have one class 2 delay pool and one class 3 delays pool, you
7144 have a total of 2 delay pools.
7146 See also delay_parameters, delay_class, delay_access for pool
7147 configuration details.
7151 TYPE: delay_pool_class
7153 IFDEF: USE_DELAY_POOLS
7156 This defines the class of each delay pool. There must be exactly one
7157 delay_class line for each delay pool. For example, to define two
7158 delay pools, one of class 2 and one of class 3, the settings above
7162 delay_pools 4 # 4 delay pools
7163 delay_class 1 2 # pool 1 is a class 2 pool
7164 delay_class 2 3 # pool 2 is a class 3 pool
7165 delay_class 3 4 # pool 3 is a class 4 pool
7166 delay_class 4 5 # pool 4 is a class 5 pool
7168 The delay pool classes are:
7170 class 1 Everything is limited by a single aggregate
7173 class 2 Everything is limited by a single aggregate
7174 bucket as well as an "individual" bucket chosen
7175 from bits 25 through 32 of the IPv4 address.
7177 class 3 Everything is limited by a single aggregate
7178 bucket as well as a "network" bucket chosen
7179 from bits 17 through 24 of the IP address and a
7180 "individual" bucket chosen from bits 17 through
7181 32 of the IPv4 address.
7183 class 4 Everything in a class 3 delay pool, with an
7184 additional limit on a per user basis. This
7185 only takes effect if the username is established
7186 in advance - by forcing authentication in your
7189 class 5 Requests are grouped according their tag (see
7190 external_acl's tag= reply).
7193 Each pool also requires a delay_parameters directive to configure the pool size
7194 and speed limits used whenever the pool is applied to a request. Along with
7195 a set of delay_access directives to determine when it is used.
7197 NOTE: If an IP address is a.b.c.d
7198 -> bits 25 through 32 are "d"
7199 -> bits 17 through 24 are "c"
7200 -> bits 17 through 32 are "c * 256 + d"
7202 NOTE-2: Due to the use of bitmasks in class 2,3,4 pools they only apply to
7203 IPv4 traffic. Class 1 and 5 pools may be used with IPv6 traffic.
7205 This clause only supports fast acl types.
7206 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7208 See also delay_parameters and delay_access.
7212 TYPE: delay_pool_access
7214 DEFAULT_DOC: Deny using the pool, unless allow rules exist in squid.conf for the pool.
7215 IFDEF: USE_DELAY_POOLS
7218 This is used to determine which delay pool a request falls into.
7220 delay_access is sorted per pool and the matching starts with pool 1,
7221 then pool 2, ..., and finally pool N. The first delay pool where the
7222 request is allowed is selected for the request. If it does not allow
7223 the request to any pool then the request is not delayed (default).
7225 For example, if you want some_big_clients in delay
7226 pool 1 and lotsa_little_clients in delay pool 2:
7228 delay_access 1 allow some_big_clients
7229 delay_access 1 deny all
7230 delay_access 2 allow lotsa_little_clients
7231 delay_access 2 deny all
7232 delay_access 3 allow authenticated_clients
7234 See also delay_parameters and delay_class.
7238 NAME: delay_parameters
7239 TYPE: delay_pool_rates
7241 IFDEF: USE_DELAY_POOLS
7244 This defines the parameters for a delay pool. Each delay pool has
7245 a number of "buckets" associated with it, as explained in the
7246 description of delay_class.
7248 For a class 1 delay pool, the syntax is:
7250 delay_parameters pool aggregate
7252 For a class 2 delay pool:
7254 delay_parameters pool aggregate individual
7256 For a class 3 delay pool:
7258 delay_parameters pool aggregate network individual
7260 For a class 4 delay pool:
7262 delay_parameters pool aggregate network individual user
7264 For a class 5 delay pool:
7266 delay_parameters pool tagrate
7268 The option variables are:
7270 pool a pool number - ie, a number between 1 and the
7271 number specified in delay_pools as used in
7274 aggregate the speed limit parameters for the aggregate bucket
7277 individual the speed limit parameters for the individual
7278 buckets (class 2, 3).
7280 network the speed limit parameters for the network buckets
7283 user the speed limit parameters for the user buckets
7286 tagrate the speed limit parameters for the tag buckets
7289 A pair of delay parameters is written restore/maximum, where restore is
7290 the number of bytes (not bits - modem and network speeds are usually
7291 quoted in bits) per second placed into the bucket, and maximum is the
7292 maximum number of bytes which can be in the bucket at any time.
7294 There must be one delay_parameters line for each delay pool.
7297 For example, if delay pool number 1 is a class 2 delay pool as in the
7298 above example, and is being used to strictly limit each host to 64Kbit/sec
7299 (plus overheads), with no overall limit, the line is:
7301 delay_parameters 1 none 8000/8000
7303 Note that 8 x 8K Byte/sec -> 64K bit/sec.
7305 Note that the word 'none' is used to represent no limit.
7308 And, if delay pool number 2 is a class 3 delay pool as in the above
7309 example, and you want to limit it to a total of 256Kbit/sec (strict limit)
7310 with each 8-bit network permitted 64Kbit/sec (strict limit) and each
7311 individual host permitted 4800bit/sec with a bucket maximum size of 64Kbits
7312 to permit a decent web page to be downloaded at a decent speed
7313 (if the network is not being limited due to overuse) but slow down
7314 large downloads more significantly:
7316 delay_parameters 2 32000/32000 8000/8000 600/8000
7318 Note that 8 x 32K Byte/sec -> 256K bit/sec.
7319 8 x 8K Byte/sec -> 64K bit/sec.
7320 8 x 600 Byte/sec -> 4800 bit/sec.
7323 Finally, for a class 4 delay pool as in the example - each user will
7324 be limited to 128Kbits/sec no matter how many workstations they are logged into.:
7326 delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000
7329 See also delay_class and delay_access.
7333 NAME: delay_initial_bucket_level
7334 COMMENT: (percent, 0-100)
7337 IFDEF: USE_DELAY_POOLS
7338 LOC: Config.Delay.initial
7340 The initial bucket percentage is used to determine how much is put
7341 in each bucket when squid starts, is reconfigured, or first notices
7342 a host accessing it (in class 2 and class 3, individual hosts and
7343 networks only have buckets associated with them once they have been
7348 CLIENT DELAY POOL PARAMETERS
7349 -----------------------------------------------------------------------------
7352 NAME: client_delay_pools
7353 TYPE: client_delay_pool_count
7355 IFDEF: USE_DELAY_POOLS
7356 LOC: Config.ClientDelay
7358 This option specifies the number of client delay pools used. It must
7359 preceed other client_delay_* options.
7362 client_delay_pools 2
7364 See also client_delay_parameters and client_delay_access.
7367 NAME: client_delay_initial_bucket_level
7368 COMMENT: (percent, 0-no_limit)
7371 IFDEF: USE_DELAY_POOLS
7372 LOC: Config.ClientDelay.initial
7374 This option determines the initial bucket size as a percentage of
7375 max_bucket_size from client_delay_parameters. Buckets are created
7376 at the time of the "first" connection from the matching IP. Idle
7377 buckets are periodically deleted up.
7379 You can specify more than 100 percent but note that such "oversized"
7380 buckets are not refilled until their size goes down to max_bucket_size
7381 from client_delay_parameters.
7384 client_delay_initial_bucket_level 50
7387 NAME: client_delay_parameters
7388 TYPE: client_delay_pool_rates
7390 IFDEF: USE_DELAY_POOLS
7391 LOC: Config.ClientDelay
7394 This option configures client-side bandwidth limits using the
7397 client_delay_parameters pool speed_limit max_bucket_size
7399 pool is an integer ID used for client_delay_access matching.
7401 speed_limit is bytes added to the bucket per second.
7403 max_bucket_size is the maximum size of a bucket, enforced after any
7404 speed_limit additions.
7406 Please see the delay_parameters option for more information and
7410 client_delay_parameters 1 1024 2048
7411 client_delay_parameters 2 51200 16384
7413 See also client_delay_access.
7417 NAME: client_delay_access
7418 TYPE: client_delay_pool_access
7420 DEFAULT_DOC: Deny use of the pool, unless allow rules exist in squid.conf for the pool.
7421 IFDEF: USE_DELAY_POOLS
7422 LOC: Config.ClientDelay
7424 This option determines the client-side delay pool for the
7427 client_delay_access pool_ID allow|deny acl_name
7429 All client_delay_access options are checked in their pool ID
7430 order, starting with pool 1. The first checked pool with allowed
7431 request is selected for the request. If no ACL matches or there
7432 are no client_delay_access options, the request bandwidth is not
7435 The ACL-selected pool is then used to find the
7436 client_delay_parameters for the request. Client-side pools are
7437 not used to aggregate clients. Clients are always aggregated
7438 based on their source IP addresses (one bucket per source IP).
7440 This clause only supports fast acl types.
7441 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7442 Additionally, only the client TCP connection details are available.
7443 ACLs testing HTTP properties will not work.
7445 Please see delay_access for more examples.
7448 client_delay_access 1 allow low_rate_network
7449 client_delay_access 2 allow vips_network
7452 See also client_delay_parameters and client_delay_pools.
7455 NAME: response_delay_pool
7456 TYPE: response_delay_pool_parameters
7458 IFDEF: USE_DELAY_POOLS
7459 LOC: Config.MessageDelay
7461 This option configures client response bandwidth limits using the
7464 response_delay_pool name [option=value] ...
7466 name the response delay pool name
7470 individual-restore The speed limit of an individual
7471 bucket(bytes/s). To be used in conjunction
7472 with 'individual-maximum'.
7474 individual-maximum The maximum number of bytes which can
7475 be placed into the individual bucket. To be used
7476 in conjunction with 'individual-restore'.
7478 aggregate-restore The speed limit for the aggregate
7479 bucket(bytes/s). To be used in conjunction with
7480 'aggregate-maximum'.
7482 aggregate-maximum The maximum number of bytes which can
7483 be placed into the aggregate bucket. To be used
7484 in conjunction with 'aggregate-restore'.
7486 initial-bucket-level The initial bucket size as a percentage
7487 of individual-maximum.
7489 Individual and(or) aggregate bucket options may not be specified,
7490 meaning no individual and(or) aggregate speed limitation.
7491 See also response_delay_pool_access and delay_parameters for
7492 terminology details.
7495 NAME: response_delay_pool_access
7496 TYPE: response_delay_pool_access
7498 DEFAULT_DOC: Deny use of the pool, unless allow rules exist in squid.conf for the pool.
7499 IFDEF: USE_DELAY_POOLS
7500 LOC: Config.MessageDelay
7502 Determines whether a specific named response delay pool is used
7503 for the transaction. The syntax for this directive is:
7505 response_delay_pool_access pool_name allow|deny acl_name
7507 All response_delay_pool_access options are checked in the order
7508 they appear in this configuration file. The first rule with a
7509 matching ACL wins. If (and only if) an "allow" rule won, Squid
7510 assigns the response to the corresponding named delay pool.
7514 WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS
7515 -----------------------------------------------------------------------------
7520 LOC: Config.Wccp.router
7522 DEFAULT_DOC: WCCP disabled.
7525 Use this option to define your WCCP ``home'' router for
7528 wccp_router supports a single WCCP(v1) router
7530 wccp2_router supports multiple WCCPv2 routers
7532 only one of the two may be used at the same time and defines
7533 which version of WCCP to use.
7537 TYPE: IpAddress_list
7538 LOC: Config.Wccp2.router
7540 DEFAULT_DOC: WCCPv2 disabled.
7543 Use this option to define your WCCP ``home'' router for
7546 wccp_router supports a single WCCP(v1) router
7548 wccp2_router supports multiple WCCPv2 routers
7550 only one of the two may be used at the same time and defines
7551 which version of WCCP to use.
7556 LOC: Config.Wccp.version
7560 This directive is only relevant if you need to set up WCCP(v1)
7561 to some very old and end-of-life Cisco routers. In all other
7562 setups it must be left unset or at the default setting.
7563 It defines an internal version in the WCCP(v1) protocol,
7564 with version 4 being the officially documented protocol.
7566 According to some users, Cisco IOS 11.2 and earlier only
7567 support WCCP version 3. If you're using that or an earlier
7568 version of IOS, you may need to change this value to 3, otherwise
7569 do not specify this parameter.
7572 NAME: wccp2_rebuild_wait
7574 LOC: Config.Wccp2.rebuildwait
7578 If this is enabled Squid will wait for the cache dir rebuild to finish
7579 before sending the first wccp2 HereIAm packet
7582 NAME: wccp2_forwarding_method
7584 LOC: Config.Wccp2.forwarding_method
7588 WCCP2 allows the setting of forwarding methods between the
7589 router/switch and the cache. Valid values are as follows:
7591 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
7592 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
7594 Currently (as of IOS 12.4) cisco routers only support GRE.
7595 Cisco switches only support the L2 redirect assignment method.
7598 NAME: wccp2_return_method
7600 LOC: Config.Wccp2.return_method
7604 WCCP2 allows the setting of return methods between the
7605 router/switch and the cache for packets that the cache
7606 decides not to handle. Valid values are as follows:
7608 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
7609 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
7611 Currently (as of IOS 12.4) cisco routers only support GRE.
7612 Cisco switches only support the L2 redirect assignment.
7614 If the "ip wccp redirect exclude in" command has been
7615 enabled on the cache interface, then it is still safe for
7616 the proxy server to use a l2 redirect method even if this
7617 option is set to GRE.
7620 NAME: wccp2_assignment_method
7622 LOC: Config.Wccp2.assignment_method
7626 WCCP2 allows the setting of methods to assign the WCCP hash
7627 Valid values are as follows:
7629 hash - Hash assignment
7630 mask - Mask assignment
7632 As a general rule, cisco routers support the hash assignment method
7633 and cisco switches support the mask assignment method.
7638 LOC: Config.Wccp2.info
7639 DEFAULT_IF_NONE: standard 0
7640 DEFAULT_DOC: Use the 'web-cache' standard service.
7643 WCCP2 allows for multiple traffic services. There are two
7644 types: "standard" and "dynamic". The standard type defines
7645 one service id - http (id 0). The dynamic service ids can be from
7646 51 to 255 inclusive. In order to use a dynamic service id
7647 one must define the type of traffic to be redirected; this is done
7648 using the wccp2_service_info option.
7650 The "standard" type does not require a wccp2_service_info option,
7651 just specifying the service id will suffice.
7653 MD5 service authentication can be enabled by adding
7654 "password=<password>" to the end of this service declaration.
7658 wccp2_service standard 0 # for the 'web-cache' standard service
7659 wccp2_service dynamic 80 # a dynamic service type which will be
7660 # fleshed out with subsequent options.
7661 wccp2_service standard 0 password=foo
7664 NAME: wccp2_service_info
7665 TYPE: wccp2_service_info
7666 LOC: Config.Wccp2.info
7670 Dynamic WCCPv2 services require further information to define the
7671 traffic you wish to have diverted.
7675 wccp2_service_info <id> protocol=<protocol> flags=<flag>,<flag>..
7676 priority=<priority> ports=<port>,<port>..
7678 The relevant WCCPv2 flags:
7679 + src_ip_hash, dst_ip_hash
7680 + source_port_hash, dst_port_hash
7681 + src_ip_alt_hash, dst_ip_alt_hash
7682 + src_port_alt_hash, dst_port_alt_hash
7685 The port list can be one to eight entries.
7689 wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source
7690 priority=240 ports=80
7692 Note: the service id must have been defined by a previous
7693 'wccp2_service dynamic <id>' entry.
7698 LOC: Config.Wccp2.weight
7702 Each cache server gets assigned a set of the destination
7703 hash proportional to their weight.
7708 LOC: Config.Wccp.address
7710 DEFAULT_DOC: Address selected by the operating system.
7713 Use this option if you require WCCPv2 to use a specific
7716 The default behavior is to not bind to any specific address.
7721 LOC: Config.Wccp2.address
7723 DEFAULT_DOC: Address selected by the operating system.
7726 Use this option if you require WCCP to use a specific
7729 The default behavior is to not bind to any specific address.
7733 PERSISTENT CONNECTION HANDLING
7734 -----------------------------------------------------------------------------
7736 Also see "pconn_timeout" in the TIMEOUTS section
7739 NAME: client_persistent_connections
7741 LOC: Config.onoff.client_pconns
7744 Persistent connection support for clients.
7745 Squid uses persistent connections (when allowed). You can use
7746 this option to disable persistent connections with clients.
7749 NAME: server_persistent_connections
7751 LOC: Config.onoff.server_pconns
7754 Persistent connection support for servers.
7755 Squid uses persistent connections (when allowed). You can use
7756 this option to disable persistent connections with servers.
7759 NAME: persistent_connection_after_error
7761 LOC: Config.onoff.error_pconns
7764 With this directive the use of persistent connections after
7765 HTTP errors can be disabled. Useful if you have clients
7766 who fail to handle errors on persistent connections proper.
7769 NAME: detect_broken_pconn
7771 LOC: Config.onoff.detect_broken_server_pconns
7774 Some servers have been found to incorrectly signal the use
7775 of HTTP/1.0 persistent connections even on replies not
7776 compatible, causing significant delays. This server problem
7777 has mostly been seen on redirects.
7779 By enabling this directive Squid attempts to detect such
7780 broken replies and automatically assume the reply is finished
7781 after 10 seconds timeout.
7785 CACHE DIGEST OPTIONS
7786 -----------------------------------------------------------------------------
7789 NAME: digest_generation
7790 IFDEF: USE_CACHE_DIGESTS
7792 LOC: Config.onoff.digest_generation
7795 This controls whether the server will generate a Cache Digest
7796 of its contents. By default, Cache Digest generation is
7797 enabled if Squid is compiled with --enable-cache-digests defined.
7800 NAME: digest_bits_per_entry
7801 IFDEF: USE_CACHE_DIGESTS
7803 LOC: Config.digest.bits_per_entry
7806 This is the number of bits of the server's Cache Digest which
7807 will be associated with the Digest entry for a given HTTP
7808 Method and URL (public key) combination. The default is 5.
7811 NAME: digest_rebuild_period
7812 IFDEF: USE_CACHE_DIGESTS
7815 LOC: Config.digest.rebuild_period
7818 This is the wait time between Cache Digest rebuilds.
7821 NAME: digest_rewrite_period
7823 IFDEF: USE_CACHE_DIGESTS
7825 LOC: Config.digest.rewrite_period
7828 This is the wait time between Cache Digest writes to
7832 NAME: digest_swapout_chunk_size
7835 IFDEF: USE_CACHE_DIGESTS
7836 LOC: Config.digest.swapout_chunk_size
7839 This is the number of bytes of the Cache Digest to write to
7840 disk at a time. It defaults to 4096 bytes (4KB), the Squid
7844 NAME: digest_rebuild_chunk_percentage
7845 COMMENT: (percent, 0-100)
7846 IFDEF: USE_CACHE_DIGESTS
7848 LOC: Config.digest.rebuild_chunk_percentage
7851 This is the percentage of the Cache Digest to be scanned at a
7852 time. By default it is set to 10% of the Cache Digest.
7857 -----------------------------------------------------------------------------
7862 LOC: Config.Port.snmp
7864 DEFAULT_DOC: SNMP disabled.
7867 The port number where Squid listens for SNMP requests. To enable
7868 SNMP support set this to a suitable port number. Port number
7869 3401 is often used for the Squid SNMP agent. By default it's
7870 set to "0" (disabled)
7878 LOC: Config.accessList.snmp
7880 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
7883 Allowing or denying access to the SNMP port.
7885 All access to the agent is denied by default.
7888 snmp_access allow|deny [!]aclname ...
7890 This clause only supports fast acl types.
7891 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7894 snmp_access allow snmppublic localhost
7895 snmp_access deny all
7898 NAME: snmp_incoming_address
7900 LOC: Config.Addrs.snmp_incoming
7902 DEFAULT_DOC: Accept SNMP packets from all machine interfaces.
7905 Just like 'udp_incoming_address', but for the SNMP port.
7907 snmp_incoming_address is used for the SNMP socket receiving
7908 messages from SNMP agents.
7910 The default snmp_incoming_address is to listen on all
7911 available network interfaces.
7914 NAME: snmp_outgoing_address
7916 LOC: Config.Addrs.snmp_outgoing
7918 DEFAULT_DOC: Use snmp_incoming_address or an address selected by the operating system.
7921 Just like 'udp_outgoing_address', but for the SNMP port.
7923 snmp_outgoing_address is used for SNMP packets returned to SNMP
7926 If snmp_outgoing_address is not set it will use the same socket
7927 as snmp_incoming_address. Only change this if you want to have
7928 SNMP replies sent using another address than where this Squid
7929 listens for SNMP queries.
7931 NOTE, snmp_incoming_address and snmp_outgoing_address can not have
7932 the same value since they both use the same port.
7937 -----------------------------------------------------------------------------
7940 NAME: icp_port udp_port
7943 DEFAULT_DOC: ICP disabled.
7944 LOC: Config.Port.icp
7946 The port number where Squid sends and receives ICP queries to
7947 and from neighbor caches. The standard UDP port for ICP is 3130.
7950 icp_port @DEFAULT_ICP_PORT@
7957 DEFAULT_DOC: HTCP disabled.
7958 LOC: Config.Port.htcp
7960 The port number where Squid sends and receives HTCP queries to
7961 and from neighbor caches. To turn it on you want to set it to
7968 NAME: log_icp_queries
7972 LOC: Config.onoff.log_udp
7974 If set, ICP queries are logged to access.log. You may wish
7975 do disable this if your ICP load is VERY high to speed things
7976 up or to simplify log analysis.
7979 NAME: udp_incoming_address
7981 LOC:Config.Addrs.udp_incoming
7983 DEFAULT_DOC: Accept packets from all machine interfaces.
7985 udp_incoming_address is used for UDP packets received from other
7988 The default behavior is to not bind to any specific address.
7990 Only change this if you want to have all UDP queries received on
7991 a specific interface/address.
7993 NOTE: udp_incoming_address is used by the ICP, HTCP, and DNS
7994 modules. Altering it will affect all of them in the same manner.
7996 see also; udp_outgoing_address
7998 NOTE, udp_incoming_address and udp_outgoing_address can not
7999 have the same value since they both use the same port.
8002 NAME: udp_outgoing_address
8004 LOC: Config.Addrs.udp_outgoing
8006 DEFAULT_DOC: Use udp_incoming_address or an address selected by the operating system.
8008 udp_outgoing_address is used for UDP packets sent out to other
8011 The default behavior is to not bind to any specific address.
8013 Instead it will use the same socket as udp_incoming_address.
8014 Only change this if you want to have UDP queries sent using another
8015 address than where this Squid listens for UDP queries from other
8018 NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS
8019 modules. Altering it will affect all of them in the same manner.
8021 see also; udp_incoming_address
8023 NOTE, udp_incoming_address and udp_outgoing_address can not
8024 have the same value since they both use the same port.
8031 LOC: Config.onoff.icp_hit_stale
8033 If you want to return ICP_HIT for stale cache objects, set this
8034 option to 'on'. If you have sibling relationships with caches
8035 in other administrative domains, this should be 'off'. If you only
8036 have sibling relationships with caches under your control,
8037 it is probably okay to set this to 'on'.
8038 If set to 'on', your siblings should use the option "allow-miss"
8039 on their cache_peer lines for connecting to you.
8042 NAME: minimum_direct_hops
8045 LOC: Config.minDirectHops
8047 If using the ICMP pinging stuff, do direct fetches for sites
8048 which are no more than this many hops away.
8051 NAME: minimum_direct_rtt
8055 LOC: Config.minDirectRtt
8057 If using the ICMP pinging stuff, do direct fetches for sites
8058 which are no more than this many rtt milliseconds away.
8064 LOC: Config.Netdb.low
8066 The low water mark for the ICMP measurement database.
8068 Note: high watermark controlled by netdb_high directive.
8070 These watermarks are counts, not percents. The defaults are
8071 (low) 900 and (high) 1000. When the high water mark is
8072 reached, database entries will be deleted until the low
8079 LOC: Config.Netdb.high
8081 The high water mark for the ICMP measurement database.
8083 Note: low watermark controlled by netdb_low directive.
8085 These watermarks are counts, not percents. The defaults are
8086 (low) 900 and (high) 1000. When the high water mark is
8087 reached, database entries will be deleted until the low
8091 NAME: netdb_ping_period
8093 LOC: Config.Netdb.period
8096 The minimum period for measuring a site. There will be at
8097 least this much delay between successive pings to the same
8098 network. The default is five minutes.
8105 LOC: Config.onoff.query_icmp
8107 If you want to ask your peers to include ICMP data in their ICP
8108 replies, enable this option.
8110 If your peer has configured Squid (during compilation) with
8111 '--enable-icmp' that peer will send ICMP pings to origin server
8112 sites of the URLs it receives. If you enable this option the
8113 ICP replies from that peer will include the ICMP data (if available).
8114 Then, when choosing a parent cache, Squid will choose the parent with
8115 the minimal RTT to the origin server. When this happens, the
8116 hierarchy field of the access.log will be
8117 "CLOSEST_PARENT_MISS". This option is off by default.
8120 NAME: test_reachability
8124 LOC: Config.onoff.test_reachability
8126 When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
8127 instead of ICP_MISS if the target host is NOT in the ICMP
8128 database, or has a zero RTT.
8131 NAME: icp_query_timeout
8134 DEFAULT_DOC: Dynamic detection.
8136 LOC: Config.Timeout.icp_query
8138 Normally Squid will automatically determine an optimal ICP
8139 query timeout value based on the round-trip-time of recent ICP
8140 queries. If you want to override the value determined by
8141 Squid, set this 'icp_query_timeout' to a non-zero value. This
8142 value is specified in MILLISECONDS, so, to use a 2-second
8143 timeout (the old default), you would write:
8145 icp_query_timeout 2000
8148 NAME: maximum_icp_query_timeout
8152 LOC: Config.Timeout.icp_query_max
8154 Normally the ICP query timeout is determined dynamically. But
8155 sometimes it can lead to very large values (say 5 seconds).
8156 Use this option to put an upper limit on the dynamic timeout
8157 value. Do NOT use this option to always use a fixed (instead
8158 of a dynamic) timeout value. To set a fixed timeout see the
8159 'icp_query_timeout' directive.
8162 NAME: minimum_icp_query_timeout
8166 LOC: Config.Timeout.icp_query_min
8168 Normally the ICP query timeout is determined dynamically. But
8169 sometimes it can lead to very small timeouts, even lower than
8170 the normal latency variance on your link due to traffic.
8171 Use this option to put an lower limit on the dynamic timeout
8172 value. Do NOT use this option to always use a fixed (instead
8173 of a dynamic) timeout value. To set a fixed timeout see the
8174 'icp_query_timeout' directive.
8177 NAME: background_ping_rate
8181 LOC: Config.backgroundPingRate
8183 Controls how often the ICP pings are sent to siblings that
8184 have background-ping set.
8188 MULTICAST ICP OPTIONS
8189 -----------------------------------------------------------------------------
8194 LOC: Config.mcast_group_list
8197 This tag specifies a list of multicast groups which your server
8198 should join to receive multicasted ICP queries.
8200 NOTE! Be very careful what you put here! Be sure you
8201 understand the difference between an ICP _query_ and an ICP
8202 _reply_. This option is to be set only if you want to RECEIVE
8203 multicast queries. Do NOT set this option to SEND multicast
8204 ICP (use cache_peer for that). ICP replies are always sent via
8205 unicast, so this option does not affect whether or not you will
8206 receive replies from multicast group members.
8208 You must be very careful to NOT use a multicast address which
8209 is already in use by another group of caches.
8211 If you are unsure about multicast, please read the Multicast
8212 chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
8214 Usage: mcast_groups 239.128.16.128 224.0.1.20
8216 By default, Squid doesn't listen on any multicast groups.
8219 NAME: mcast_miss_addr
8220 IFDEF: MULTICAST_MISS_STREAM
8222 LOC: Config.mcast_miss.addr
8224 DEFAULT_DOC: disabled.
8226 If you enable this option, every "cache miss" URL will
8227 be sent out on the specified multicast address.
8229 Do not enable this option unless you are are absolutely
8230 certain you understand what you are doing.
8233 NAME: mcast_miss_ttl
8234 IFDEF: MULTICAST_MISS_STREAM
8236 LOC: Config.mcast_miss.ttl
8239 This is the time-to-live value for packets multicasted
8240 when multicasting off cache miss URLs is enabled. By
8241 default this is set to 'site scope', i.e. 16.
8244 NAME: mcast_miss_port
8245 IFDEF: MULTICAST_MISS_STREAM
8247 LOC: Config.mcast_miss.port
8250 This is the port number to be used in conjunction with
8254 NAME: mcast_miss_encode_key
8255 IFDEF: MULTICAST_MISS_STREAM
8257 LOC: Config.mcast_miss.encode_key
8258 DEFAULT: XXXXXXXXXXXXXXXX
8260 The URLs that are sent in the multicast miss stream are
8261 encrypted. This is the encryption key.
8264 NAME: mcast_icp_query_timeout
8268 LOC: Config.Timeout.mcast_icp_query
8270 For multicast peers, Squid regularly sends out ICP "probes" to
8271 count how many other peers are listening on the given multicast
8272 address. This value specifies how long Squid should wait to
8273 count all the replies. The default is 2000 msec, or 2
8278 INTERNAL ICON OPTIONS
8279 -----------------------------------------------------------------------------
8282 NAME: icon_directory
8284 LOC: Config.icons.directory
8285 DEFAULT: @DEFAULT_ICON_DIR@
8287 Where the icons are stored. These are normally kept in
8291 NAME: global_internal_static
8293 LOC: Config.onoff.global_internal_static
8296 This directive controls is Squid should intercept all requests for
8297 /squid-internal-static/ no matter which host the URL is requesting
8298 (default on setting), or if nothing special should be done for
8299 such URLs (off setting). The purpose of this directive is to make
8300 icons etc work better in complex cache hierarchies where it may
8301 not always be possible for all corners in the cache mesh to reach
8302 the server generating a directory listing.
8305 NAME: short_icon_urls
8307 LOC: Config.icons.use_short_names
8310 If this is enabled Squid will use short URLs for icons.
8311 If disabled it will revert to the old behavior of including
8312 it's own name and port in the URL.
8314 If you run a complex cache hierarchy with a mix of Squid and
8315 other proxies you may need to disable this directive.
8320 -----------------------------------------------------------------------------
8323 NAME: error_directory
8325 LOC: Config.errorDirectory
8327 DEFAULT_DOC: Send error pages in the clients preferred language
8329 If you wish to create your own versions of the default
8330 error files to customize them to suit your company copy
8331 the error/template files to another directory and point
8334 WARNING: This option will disable multi-language support
8335 on error pages if used.
8337 The squid developers are interested in making squid available in
8338 a wide variety of languages. If you are making translations for a
8339 language that Squid does not currently provide please consider
8340 contributing your translation back to the project.
8341 http://wiki.squid-cache.org/Translations
8343 The squid developers working on translations are happy to supply drop-in
8344 translated error files in exchange for any new language contributions.
8347 NAME: error_default_language
8348 IFDEF: USE_ERR_LOCALES
8350 LOC: Config.errorDefaultLanguage
8352 DEFAULT_DOC: Generate English language pages.
8354 Set the default language which squid will send error pages in
8355 if no existing translation matches the clients language
8358 If unset (default) generic English will be used.
8360 The squid developers are interested in making squid available in
8361 a wide variety of languages. If you are interested in making
8362 translations for any language see the squid wiki for details.
8363 http://wiki.squid-cache.org/Translations
8366 NAME: error_log_languages
8367 IFDEF: USE_ERR_LOCALES
8369 LOC: Config.errorLogMissingLanguages
8372 Log to cache.log what languages users are attempting to
8373 auto-negotiate for translations.
8375 Successful negotiations are not logged. Only failures
8376 have meaning to indicate that Squid may need an upgrade
8377 of its error page translations.
8380 NAME: err_page_stylesheet
8382 LOC: Config.errorStylesheet
8383 DEFAULT: @DEFAULT_CONFIG_DIR@/errorpage.css
8385 CSS Stylesheet to pattern the display of Squid default error pages.
8387 For information on CSS see http://www.w3.org/Style/CSS/
8392 LOC: Config.errHtmlText
8395 HTML text to include in error messages. Make this a "mailto"
8396 URL to your admin address, or maybe just a link to your
8397 organizations Web page.
8399 To include this in your error messages, you must rewrite
8400 the error template files (found in the "errors" directory).
8401 Wherever you want the 'err_html_text' line to appear,
8402 insert a %L tag in the error template file.
8405 NAME: email_err_data
8408 LOC: Config.onoff.emailErrData
8411 If enabled, information about the occurred error will be
8412 included in the mailto links of the ERR pages (if %W is set)
8413 so that the email body contains the data.
8414 Syntax is <A HREF="mailto:%w%W">%w</A>
8419 LOC: Config.denyInfoList
8422 Usage: deny_info err_page_name acl
8423 or deny_info http://... acl
8424 or deny_info TCP_RESET acl
8426 This can be used to return a ERR_ page for requests which
8427 do not pass the 'http_access' rules. Squid remembers the last
8428 acl it evaluated in http_access, and if a 'deny_info' line exists
8429 for that ACL Squid returns a corresponding error page.
8431 The acl is typically the last acl on the http_access deny line which
8432 denied access. The exceptions to this rule are:
8433 - When Squid needs to request authentication credentials. It's then
8434 the first authentication related acl encountered
8435 - When none of the http_access lines matches. It's then the last
8436 acl processed on the last http_access line.
8437 - When the decision to deny access was made by an adaptation service,
8438 the acl name is the corresponding eCAP or ICAP service_name.
8440 NP: If providing your own custom error pages with error_directory
8441 you may also specify them by your custom file name:
8442 Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
8444 By defaut Squid will send "403 Forbidden". A different 4xx or 5xx
8445 may be specified by prefixing the file name with the code and a colon.
8446 e.g. 404:ERR_CUSTOM_ACCESS_DENIED
8448 Alternatively you can tell Squid to reset the TCP connection
8449 by specifying TCP_RESET.
8451 Or you can specify an error URL or URL pattern. The browsers will
8452 get redirected to the specified URL after formatting tags have
8453 been replaced. Redirect will be done with 302 or 307 according to
8454 HTTP/1.1 specs. A different 3xx code may be specified by prefixing
8455 the URL. e.g. 303:http://example.com/
8458 %a - username (if available. Password NOT included)
8459 %A - Local listening IP address the client connection was connected to
8462 %E - Error description
8464 %H - Request domain name
8465 %i - Client IP Address
8467 %O - Unescaped message result from external ACL helper
8468 %o - Message result from external ACL helper
8469 %p - Request Port number
8470 %P - Request Protocol name
8471 %R - Request URL path
8472 %T - Timestamp in RFC 1123 format
8473 %U - Full canonical URL from client
8474 (HTTPS URLs terminate with *)
8475 %u - Full canonical URL from client
8476 %w - Admin email from squid.conf
8478 %% - Literal percent (%) code
8483 OPTIONS INFLUENCING REQUEST FORWARDING
8484 -----------------------------------------------------------------------------
8487 NAME: nonhierarchical_direct
8489 LOC: Config.onoff.nonhierarchical_direct
8492 By default, Squid will send any non-hierarchical requests
8493 (not cacheable request type) direct to origin servers.
8495 When this is set to "off", Squid will prefer to send these
8496 requests to parents.
8498 Note that in most configurations, by turning this off you will only
8499 add latency to these request without any improvement in global hit
8502 This option only sets a preference. If the parent is unavailable a
8503 direct connection to the origin server may still be attempted. To
8504 completely prevent direct connections use never_direct.
8509 LOC: Config.onoff.prefer_direct
8512 Normally Squid tries to use parents for most requests. If you for some
8513 reason like it to first try going direct and only use a parent if
8514 going direct fails set this to on.
8516 By combining nonhierarchical_direct off and prefer_direct on you
8517 can set up Squid to use a parent as a backup path if going direct
8520 Note: If you want Squid to use parents for all requests see
8521 the never_direct directive. prefer_direct only modifies how Squid
8522 acts on cacheable requests.
8525 NAME: cache_miss_revalidate
8529 LOC: Config.onoff.cache_miss_revalidate
8531 RFC 7232 defines a conditional request mechanism to prevent
8532 response objects being unnecessarily transferred over the network.
8533 If that mechanism is used by the client and a cache MISS occurs
8534 it can prevent new cache entries being created.
8536 This option determines whether Squid on cache MISS will pass the
8537 client revalidation request to the server or tries to fetch new
8538 content for caching. It can be useful while the cache is mostly
8539 empty to more quickly have the cache populated by generating
8540 non-conditional GETs.
8542 When set to 'on' (default), Squid will pass all client If-* headers
8543 to the server. This permits server responses without a cacheable
8544 payload to be delivered and on MISS no new cache entry is created.
8546 When set to 'off' and if the request is cacheable, Squid will
8547 remove the clients If-Modified-Since and If-None-Match headers from
8548 the request sent to the server. This requests a 200 status response
8549 from the server to create a new cache entry with.
8554 LOC: Config.accessList.AlwaysDirect
8556 DEFAULT_DOC: Prevent any cache_peer being used for this request.
8558 Usage: always_direct allow|deny [!]aclname ...
8560 Here you can use ACL elements to specify requests which should
8561 ALWAYS be forwarded by Squid to the origin servers without using
8562 any peers. For example, to always directly forward requests for
8563 local servers ignoring any parents or siblings you may have use
8566 acl local-servers dstdomain my.domain.net
8567 always_direct allow local-servers
8569 To always forward FTP requests directly, use
8572 always_direct allow FTP
8574 NOTE: There is a similar, but opposite option named
8575 'never_direct'. You need to be aware that "always_direct deny
8576 foo" is NOT the same thing as "never_direct allow foo". You
8577 may need to use a deny rule to exclude a more-specific case of
8578 some other rule. Example:
8580 acl local-external dstdomain external.foo.net
8581 acl local-servers dstdomain .foo.net
8582 always_direct deny local-external
8583 always_direct allow local-servers
8585 NOTE: If your goal is to make the client forward the request
8586 directly to the origin server bypassing Squid then this needs
8587 to be done in the client configuration. Squid configuration
8588 can only tell Squid how Squid should fetch the object.
8590 NOTE: This directive is not related to caching. The replies
8591 is cached as usual even if you use always_direct. To not cache
8592 the replies see the 'cache' directive.
8594 This clause supports both fast and slow acl types.
8595 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
8600 LOC: Config.accessList.NeverDirect
8602 DEFAULT_DOC: Allow DNS results to be used for this request.
8604 Usage: never_direct allow|deny [!]aclname ...
8606 never_direct is the opposite of always_direct. Please read
8607 the description for always_direct if you have not already.
8609 With 'never_direct' you can use ACL elements to specify
8610 requests which should NEVER be forwarded directly to origin
8611 servers. For example, to force the use of a proxy for all
8612 requests, except those in your local domain use something like:
8614 acl local-servers dstdomain .foo.net
8615 never_direct deny local-servers
8616 never_direct allow all
8618 or if Squid is inside a firewall and there are local intranet
8619 servers inside the firewall use something like:
8621 acl local-intranet dstdomain .foo.net
8622 acl local-external dstdomain external.foo.net
8623 always_direct deny local-external
8624 always_direct allow local-intranet
8625 never_direct allow all
8627 This clause supports both fast and slow acl types.
8628 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
8632 ADVANCED NETWORKING OPTIONS
8633 -----------------------------------------------------------------------------
8636 NAME: incoming_udp_average incoming_icp_average
8639 LOC: Config.comm_incoming.udp.average
8641 Heavy voodoo here. I can't even believe you are reading this.
8642 Are you crazy? Don't even think about adjusting these unless
8643 you understand the algorithms in comm_select.c first!
8646 NAME: incoming_tcp_average incoming_http_average
8649 LOC: Config.comm_incoming.tcp.average
8651 Heavy voodoo here. I can't even believe you are reading this.
8652 Are you crazy? Don't even think about adjusting these unless
8653 you understand the algorithms in comm_select.c first!
8656 NAME: incoming_dns_average
8659 LOC: Config.comm_incoming.dns.average
8661 Heavy voodoo here. I can't even believe you are reading this.
8662 Are you crazy? Don't even think about adjusting these unless
8663 you understand the algorithms in comm_select.c first!
8666 NAME: min_udp_poll_cnt min_icp_poll_cnt
8669 LOC: Config.comm_incoming.udp.min_poll
8671 Heavy voodoo here. I can't even believe you are reading this.
8672 Are you crazy? Don't even think about adjusting these unless
8673 you understand the algorithms in comm_select.c first!
8676 NAME: min_dns_poll_cnt
8679 LOC: Config.comm_incoming.dns.min_poll
8681 Heavy voodoo here. I can't even believe you are reading this.
8682 Are you crazy? Don't even think about adjusting these unless
8683 you understand the algorithms in comm_select.c first!
8686 NAME: min_tcp_poll_cnt min_http_poll_cnt
8689 LOC: Config.comm_incoming.tcp.min_poll
8691 Heavy voodoo here. I can't even believe you are reading this.
8692 Are you crazy? Don't even think about adjusting these unless
8693 you understand the algorithms in comm_select.c first!
8699 LOC: Config.accept_filter
8703 The name of an accept(2) filter to install on Squid's
8704 listen socket(s). This feature is perhaps specific to
8705 FreeBSD and requires support in the kernel.
8707 The 'httpready' filter delays delivering new connections
8708 to Squid until a full HTTP request has been received.
8709 See the accf_http(9) man page for details.
8711 The 'dataready' filter delays delivering new connections
8712 to Squid until there is some data to process.
8713 See the accf_dataready(9) man page for details.
8717 The 'data' filter delays delivering of new connections
8718 to Squid until there is some data to process by TCP_ACCEPT_DEFER.
8719 You may optionally specify a number of seconds to wait by
8720 'data=N' where N is the number of seconds. Defaults to 30
8721 if not specified. See the tcp(7) man page for details.
8724 accept_filter httpready
8729 NAME: client_ip_max_connections
8731 LOC: Config.client_ip_max_connections
8733 DEFAULT_DOC: No limit.
8735 Set an absolute limit on the number of connections a single
8736 client IP can use. Any more than this and Squid will begin to drop
8737 new connections from the client until it closes some links.
8739 Note that this is a global limit. It affects all HTTP, HTCP, Gopher and FTP
8740 connections from the client. For finer control use the ACL access controls.
8742 Requires client_db to be enabled (the default).
8744 WARNING: This may noticably slow down traffic received via external proxies
8745 or NAT devices and cause them to rebound error messages back to their clients.
8748 NAME: tcp_recv_bufsize
8752 DEFAULT_DOC: Use operating system TCP defaults.
8753 LOC: Config.tcpRcvBufsz
8755 Size of receive buffer to set for TCP sockets. Probably just
8756 as easy to change your kernel's default.
8757 Omit from squid.conf to use the default buffer size.
8762 -----------------------------------------------------------------------------
8769 LOC: Adaptation::Icap::TheConfig.onoff
8772 If you want to enable the ICAP module support, set this to on.
8775 NAME: icap_connect_timeout
8778 LOC: Adaptation::Icap::TheConfig.connect_timeout_raw
8781 This parameter specifies how long to wait for the TCP connect to
8782 the requested ICAP server to complete before giving up and either
8783 terminating the HTTP transaction or bypassing the failure.
8785 The default for optional services is peer_connect_timeout.
8786 The default for essential services is connect_timeout.
8787 If this option is explicitly set, its value applies to all services.
8790 NAME: icap_io_timeout
8794 DEFAULT_DOC: Use read_timeout.
8795 LOC: Adaptation::Icap::TheConfig.io_timeout_raw
8798 This parameter specifies how long to wait for an I/O activity on
8799 an established, active ICAP connection before giving up and
8800 either terminating the HTTP transaction or bypassing the
8804 NAME: icap_service_failure_limit
8805 COMMENT: limit [in memory-depth time-units]
8806 TYPE: icap_service_failure_limit
8808 LOC: Adaptation::Icap::TheConfig
8811 The limit specifies the number of failures that Squid tolerates
8812 when establishing a new TCP connection with an ICAP service. If
8813 the number of failures exceeds the limit, the ICAP service is
8814 not used for new ICAP requests until it is time to refresh its
8817 A negative value disables the limit. Without the limit, an ICAP
8818 service will not be considered down due to connectivity failures
8819 between ICAP OPTIONS requests.
8821 Squid forgets ICAP service failures older than the specified
8822 value of memory-depth. The memory fading algorithm
8823 is approximate because Squid does not remember individual
8824 errors but groups them instead, splitting the option
8825 value into ten time slots of equal length.
8827 When memory-depth is 0 and by default this option has no
8828 effect on service failure expiration.
8830 Squid always forgets failures when updating service settings
8831 using an ICAP OPTIONS transaction, regardless of this option
8835 # suspend service usage after 10 failures in 5 seconds:
8836 icap_service_failure_limit 10 in 5 seconds
8839 NAME: icap_service_revival_delay
8842 LOC: Adaptation::Icap::TheConfig.service_revival_delay
8845 The delay specifies the number of seconds to wait after an ICAP
8846 OPTIONS request failure before requesting the options again. The
8847 failed ICAP service is considered "down" until fresh OPTIONS are
8850 The actual delay cannot be smaller than the hardcoded minimum
8851 delay of 30 seconds.
8854 NAME: icap_preview_enable
8858 LOC: Adaptation::Icap::TheConfig.preview_enable
8861 The ICAP Preview feature allows the ICAP server to handle the
8862 HTTP message by looking only at the beginning of the message body
8863 or even without receiving the body at all. In some environments,
8864 previews greatly speedup ICAP processing.
8866 During an ICAP OPTIONS transaction, the server may tell Squid what
8867 HTTP messages should be previewed and how big the preview should be.
8868 Squid will not use Preview if the server did not request one.
8870 To disable ICAP Preview for all ICAP services, regardless of
8871 individual ICAP server OPTIONS responses, set this option to "off".
8873 icap_preview_enable off
8876 NAME: icap_preview_size
8879 LOC: Adaptation::Icap::TheConfig.preview_size
8881 DEFAULT_DOC: No preview sent.
8883 The default size of preview data to be sent to the ICAP server.
8884 This value might be overwritten on a per server basis by OPTIONS requests.
8887 NAME: icap_206_enable
8891 LOC: Adaptation::Icap::TheConfig.allow206_enable
8894 206 (Partial Content) responses is an ICAP extension that allows the
8895 ICAP agents to optionally combine adapted and original HTTP message
8896 content. The decision to combine is postponed until the end of the
8897 ICAP response. Squid supports Partial Content extension by default.
8899 Activation of the Partial Content extension is negotiated with each
8900 ICAP service during OPTIONS exchange. Most ICAP servers should handle
8901 negotation correctly even if they do not support the extension, but
8902 some might fail. To disable Partial Content support for all ICAP
8903 services and to avoid any negotiation, set this option to "off".
8909 NAME: icap_default_options_ttl
8912 LOC: Adaptation::Icap::TheConfig.default_options_ttl
8915 The default TTL value for ICAP OPTIONS responses that don't have
8916 an Options-TTL header.
8919 NAME: icap_persistent_connections
8923 LOC: Adaptation::Icap::TheConfig.reuse_connections
8926 Whether or not Squid should use persistent connections to
8930 NAME: adaptation_send_client_ip icap_send_client_ip
8932 IFDEF: USE_ADAPTATION
8934 LOC: Adaptation::Config::send_client_ip
8937 If enabled, Squid shares HTTP client IP information with adaptation
8938 services. For ICAP, Squid adds the X-Client-IP header to ICAP requests.
8939 For eCAP, Squid sets the libecap::metaClientIp transaction option.
8941 See also: adaptation_uses_indirect_client
8944 NAME: adaptation_send_username icap_send_client_username
8946 IFDEF: USE_ADAPTATION
8948 LOC: Adaptation::Config::send_username
8951 This sends authenticated HTTP client username (if available) to
8952 the adaptation service.
8954 For ICAP, the username value is encoded based on the
8955 icap_client_username_encode option and is sent using the header
8956 specified by the icap_client_username_header option.
8959 NAME: icap_client_username_header
8962 LOC: Adaptation::Icap::TheConfig.client_username_header
8963 DEFAULT: X-Client-Username
8965 ICAP request header name to use for adaptation_send_username.
8968 NAME: icap_client_username_encode
8972 LOC: Adaptation::Icap::TheConfig.client_username_encode
8975 Whether to base64 encode the authenticated client username.
8979 TYPE: icap_service_type
8981 LOC: Adaptation::Icap::TheConfig
8984 Defines a single ICAP service using the following format:
8986 icap_service id vectoring_point uri [option ...]
8989 an opaque identifier or name which is used to direct traffic to
8990 this specific service. Must be unique among all adaptation
8991 services in squid.conf.
8993 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
8994 This specifies at which point of transaction processing the
8995 ICAP service should be activated. *_postcache vectoring points
8996 are not yet supported.
8998 uri: icap://servername:port/servicepath
8999 ICAP server and service location.
9000 icaps://servername:port/servicepath
9001 The "icap:" URI scheme is used for traditional ICAP server and
9002 service location (default port is 1344, connections are not
9003 encrypted). The "icaps:" URI scheme is for Secure ICAP
9004 services that use SSL/TLS-encrypted ICAP connections (by
9005 default, on port 11344).
9007 ICAP does not allow a single service to handle both REQMOD and RESPMOD
9008 transactions. Squid does not enforce that requirement. You can specify
9009 services with the same service_url and different vectoring_points. You
9010 can even specify multiple identical services as long as their
9011 service_names differ.
9013 To activate a service, use the adaptation_access directive. To group
9014 services, use adaptation_service_chain and adaptation_service_set.
9016 Service options are separated by white space. ICAP services support
9017 the following name=value options:
9020 If set to 'on' or '1', the ICAP service is treated as
9021 optional. If the service cannot be reached or malfunctions,
9022 Squid will try to ignore any errors and process the message as
9023 if the service was not enabled. No all ICAP errors can be
9024 bypassed. If set to 0, the ICAP service is treated as
9025 essential and all ICAP errors will result in an error page
9026 returned to the HTTP client.
9028 Bypass is off by default: services are treated as essential.
9031 If set to 'on' or '1', the ICAP service is allowed to
9032 dynamically change the current message adaptation plan by
9033 returning a chain of services to be used next. The services
9034 are specified using the X-Next-Services ICAP response header
9035 value, formatted as a comma-separated list of service names.
9036 Each named service should be configured in squid.conf. Other
9037 services are ignored. An empty X-Next-Services value results
9038 in an empty plan which ends the current adaptation.
9040 Dynamic adaptation plan may cross or cover multiple supported
9041 vectoring points in their natural processing order.
9043 Routing is not allowed by default: the ICAP X-Next-Services
9044 response header is ignored.
9047 Only has effect on split-stack systems. The default on those systems
9048 is to use IPv4-only connections. When set to 'on' this option will
9049 make Squid use IPv6-only connections to contact this ICAP service.
9051 on-overload=block|bypass|wait|force
9052 If the service Max-Connections limit has been reached, do
9053 one of the following for each new ICAP transaction:
9054 * block: send an HTTP error response to the client
9055 * bypass: ignore the "over-connected" ICAP service
9056 * wait: wait (in a FIFO queue) for an ICAP connection slot
9057 * force: proceed, ignoring the Max-Connections limit
9059 In SMP mode with N workers, each worker assumes the service
9060 connection limit is Max-Connections/N, even though not all
9061 workers may use a given service.
9063 The default value is "bypass" if service is bypassable,
9064 otherwise it is set to "wait".
9068 Use the given number as the Max-Connections limit, regardless
9069 of the Max-Connections value given by the service, if any.
9071 connection-encryption=on|off
9072 Determines the ICAP service effect on the connections_encrypted
9075 The default is "on" for Secure ICAP services (i.e., those
9076 with the icaps:// service URIs scheme) and "off" for plain ICAP
9079 Does not affect ICAP connections (e.g., does not turn Secure
9082 ==== ICAPS / TLS OPTIONS ====
9084 These options are used for Secure ICAP (icaps://....) services only.
9086 tls-cert=/path/to/ssl/certificate
9087 A client X.509 certificate to use when connecting to
9090 tls-key=/path/to/ssl/key
9091 The private key corresponding to the previous
9094 If tls-key= is not specified tls-cert= is assumed to
9095 reference a PEM file containing both the certificate
9098 tls-cipher=... The list of valid TLS/SSL ciphers to use when connecting
9099 to this icap server.
9102 The minimum TLS protocol version to permit. To control
9103 SSLv3 use the tls-options= parameter.
9104 Supported Values: 1.0 (default), 1.1, 1.2
9106 tls-options=... Specify various OpenSSL library options:
9108 NO_SSLv3 Disallow the use of SSLv3
9111 Always create a new key when using
9112 temporary/ephemeral DH key exchanges
9114 ALL Enable various bug workarounds
9115 suggested as "harmless" by OpenSSL
9116 Be warned that this reduces SSL/TLS
9117 strength to some attacks.
9119 See the OpenSSL SSL_CTX_set_options documentation for a
9120 more complete list. Options relevant only to SSLv2 are
9123 tls-cafile= PEM file containing CA certificates to use when verifying
9124 the icap server certificate.
9125 Use to specify intermediate CA certificate(s) if not sent
9126 by the server. Or the full CA chain for the server when
9127 using the tls-default-ca=off flag.
9128 May be repeated to load multiple files.
9130 tls-capath=... A directory containing additional CA certificates to
9131 use when verifying the icap server certificate.
9132 Requires OpenSSL or LibreSSL.
9134 tls-crlfile=... A certificate revocation list file to use when
9135 verifying the icap server certificate.
9137 tls-flags=... Specify various flags modifying the Squid TLS implementation:
9140 Accept certificates even if they fail to
9143 Don't verify the icap server certificate
9144 matches the server name
9146 tls-default-ca[=off]
9147 Whether to use the system Trusted CAs. Default is ON.
9149 tls-domain= The icap server name as advertised in it's certificate.
9150 Used for verifying the correctness of the received icap
9151 server certificate. If not specified the icap server
9152 hostname extracted from ICAP URI will be used.
9154 Older icap_service format without optional named parameters is
9155 deprecated but supported for backward compatibility.
9158 icap_service svcBlocker reqmod_precache icap://icap1.mydomain.net:1344/reqmod bypass=0
9159 icap_service svcLogger reqmod_precache icaps://icap2.mydomain.net:11344/reqmod routing=on
9163 TYPE: icap_class_type
9168 This deprecated option was documented to define an ICAP service
9169 chain, even though it actually defined a set of similar, redundant
9170 services, and the chains were not supported.
9172 To define a set of redundant services, please use the
9173 adaptation_service_set directive. For service chains, use
9174 adaptation_service_chain.
9178 TYPE: icap_access_type
9183 This option is deprecated. Please use adaptation_access, which
9184 has the same ICAP functionality, but comes with better
9185 documentation, and eCAP support.
9190 -----------------------------------------------------------------------------
9197 LOC: Adaptation::Ecap::TheConfig.onoff
9200 Controls whether eCAP support is enabled.
9204 TYPE: ecap_service_type
9206 LOC: Adaptation::Ecap::TheConfig
9209 Defines a single eCAP service
9211 ecap_service id vectoring_point uri [option ...]
9214 an opaque identifier or name which is used to direct traffic to
9215 this specific service. Must be unique among all adaptation
9216 services in squid.conf.
9218 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
9219 This specifies at which point of transaction processing the
9220 eCAP service should be activated. *_postcache vectoring points
9221 are not yet supported.
9223 uri: ecap://vendor/service_name?custom&cgi=style¶meters=optional
9224 Squid uses the eCAP service URI to match this configuration
9225 line with one of the dynamically loaded services. Each loaded
9226 eCAP service must have a unique URI. Obtain the right URI from
9227 the service provider.
9229 To activate a service, use the adaptation_access directive. To group
9230 services, use adaptation_service_chain and adaptation_service_set.
9232 Service options are separated by white space. eCAP services support
9233 the following name=value options:
9236 If set to 'on' or '1', the eCAP service is treated as optional.
9237 If the service cannot be reached or malfunctions, Squid will try
9238 to ignore any errors and process the message as if the service
9239 was not enabled. No all eCAP errors can be bypassed.
9240 If set to 'off' or '0', the eCAP service is treated as essential
9241 and all eCAP errors will result in an error page returned to the
9244 Bypass is off by default: services are treated as essential.
9247 If set to 'on' or '1', the eCAP service is allowed to
9248 dynamically change the current message adaptation plan by
9249 returning a chain of services to be used next.
9251 Dynamic adaptation plan may cross or cover multiple supported
9252 vectoring points in their natural processing order.
9254 Routing is not allowed by default.
9256 connection-encryption=on|off
9257 Determines the eCAP service effect on the connections_encrypted
9260 Defaults to "on", which does not taint the master transaction
9263 Does not affect eCAP API calls.
9265 Older ecap_service format without optional named parameters is
9266 deprecated but supported for backward compatibility.
9270 ecap_service s1 reqmod_precache ecap://filters.R.us/leakDetector?on_error=block bypass=off
9271 ecap_service s2 respmod_precache ecap://filters.R.us/virusFilter config=/etc/vf.cfg bypass=on
9274 NAME: loadable_modules
9276 IFDEF: USE_LOADABLE_MODULES
9277 LOC: Config.loadable_module_names
9280 Instructs Squid to load the specified dynamic module(s) or activate
9281 preloaded module(s).
9283 loadable_modules @DEFAULT_PREFIX@/lib/MinimalAdapter.so
9287 MESSAGE ADAPTATION OPTIONS
9288 -----------------------------------------------------------------------------
9291 NAME: adaptation_service_set
9292 TYPE: adaptation_service_set_type
9293 IFDEF: USE_ADAPTATION
9298 Configures an ordered set of similar, redundant services. This is
9299 useful when hot standby or backup adaptation servers are available.
9301 adaptation_service_set set_name service_name1 service_name2 ...
9303 The named services are used in the set declaration order. The first
9304 applicable adaptation service from the set is used first. The next
9305 applicable service is tried if and only if the transaction with the
9306 previous service fails and the message waiting to be adapted is still
9309 When adaptation starts, broken services are ignored as if they were
9310 not a part of the set. A broken service is a down optional service.
9312 The services in a set must be attached to the same vectoring point
9313 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
9315 If all services in a set are optional then adaptation failures are
9316 bypassable. If all services in the set are essential, then a
9317 transaction failure with one service may still be retried using
9318 another service from the set, but when all services fail, the master
9319 transaction fails as well.
9321 A set may contain a mix of optional and essential services, but that
9322 is likely to lead to surprising results because broken services become
9323 ignored (see above), making previously bypassable failures fatal.
9324 Technically, it is the bypassability of the last failed service that
9327 See also: adaptation_access adaptation_service_chain
9330 adaptation_service_set svcBlocker urlFilterPrimary urlFilterBackup
9331 adaptation service_set svcLogger loggerLocal loggerRemote
9334 NAME: adaptation_service_chain
9335 TYPE: adaptation_service_chain_type
9336 IFDEF: USE_ADAPTATION
9341 Configures a list of complementary services that will be applied
9342 one-by-one, forming an adaptation chain or pipeline. This is useful
9343 when Squid must perform different adaptations on the same message.
9345 adaptation_service_chain chain_name service_name1 svc_name2 ...
9347 The named services are used in the chain declaration order. The first
9348 applicable adaptation service from the chain is used first. The next
9349 applicable service is applied to the successful adaptation results of
9350 the previous service in the chain.
9352 When adaptation starts, broken services are ignored as if they were
9353 not a part of the chain. A broken service is a down optional service.
9355 Request satisfaction terminates the adaptation chain because Squid
9356 does not currently allow declaration of RESPMOD services at the
9357 "reqmod_precache" vectoring point (see icap_service or ecap_service).
9359 The services in a chain must be attached to the same vectoring point
9360 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
9362 A chain may contain a mix of optional and essential services. If an
9363 essential adaptation fails (or the failure cannot be bypassed for
9364 other reasons), the master transaction fails. Otherwise, the failure
9365 is bypassed as if the failed adaptation service was not in the chain.
9367 See also: adaptation_access adaptation_service_set
9370 adaptation_service_chain svcRequest requestLogger urlFilter leakDetector
9373 NAME: adaptation_access
9374 TYPE: adaptation_access_type
9375 IFDEF: USE_ADAPTATION
9378 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
9380 Sends an HTTP transaction to an ICAP or eCAP adaptation service.
9382 adaptation_access service_name allow|deny [!]aclname...
9383 adaptation_access set_name allow|deny [!]aclname...
9385 At each supported vectoring point, the adaptation_access
9386 statements are processed in the order they appear in this
9387 configuration file. Statements pointing to the following services
9388 are ignored (i.e., skipped without checking their ACL):
9390 - services serving different vectoring points
9391 - "broken-but-bypassable" services
9392 - "up" services configured to ignore such transactions
9393 (e.g., based on the ICAP Transfer-Ignore header).
9395 When a set_name is used, all services in the set are checked
9396 using the same rules, to find the first applicable one. See
9397 adaptation_service_set for details.
9399 If an access list is checked and there is a match, the
9400 processing stops: For an "allow" rule, the corresponding
9401 adaptation service is used for the transaction. For a "deny"
9402 rule, no adaptation service is activated.
9404 It is currently not possible to apply more than one adaptation
9405 service at the same vectoring point to the same HTTP transaction.
9407 See also: icap_service and ecap_service
9410 adaptation_access service_1 allow all
9413 NAME: adaptation_service_iteration_limit
9415 IFDEF: USE_ADAPTATION
9416 LOC: Adaptation::Config::service_iteration_limit
9419 Limits the number of iterations allowed when applying adaptation
9420 services to a message. If your longest adaptation set or chain
9421 may have more than 16 services, increase the limit beyond its
9422 default value of 16. If detecting infinite iteration loops sooner
9423 is critical, make the iteration limit match the actual number
9424 of services in your longest adaptation set or chain.
9426 Infinite adaptation loops are most likely with routing services.
9428 See also: icap_service routing=1
9431 NAME: adaptation_masterx_shared_names
9433 IFDEF: USE_ADAPTATION
9434 LOC: Adaptation::Config::masterx_shared_name
9437 For each master transaction (i.e., the HTTP request and response
9438 sequence, including all related ICAP and eCAP exchanges), Squid
9439 maintains a table of metadata. The table entries are (name, value)
9440 pairs shared among eCAP and ICAP exchanges. The table is destroyed
9441 with the master transaction.
9443 This option specifies the table entry names that Squid must accept
9444 from and forward to the adaptation transactions.
9446 An ICAP REQMOD or RESPMOD transaction may set an entry in the
9447 shared table by returning an ICAP header field with a name
9448 specified in adaptation_masterx_shared_names.
9450 An eCAP REQMOD or RESPMOD transaction may set an entry in the
9451 shared table by implementing the libecap::visitEachOption() API
9452 to provide an option with a name specified in
9453 adaptation_masterx_shared_names.
9455 Squid will store and forward the set entry to subsequent adaptation
9456 transactions within the same master transaction scope.
9458 Only one shared entry name is supported at this time.
9461 # share authentication information among ICAP services
9462 adaptation_masterx_shared_names X-Subscriber-ID
9465 NAME: adaptation_meta
9467 IFDEF: USE_ADAPTATION
9468 LOC: Adaptation::Config::metaHeaders
9471 This option allows Squid administrator to add custom ICAP request
9472 headers or eCAP options to Squid ICAP requests or eCAP transactions.
9473 Use it to pass custom authentication tokens and other
9474 transaction-state related meta information to an ICAP/eCAP service.
9476 The addition of a meta header is ACL-driven:
9477 adaptation_meta name value [!]aclname ...
9479 Processing for a given header name stops after the first ACL list match.
9480 Thus, it is impossible to add two headers with the same name. If no ACL
9481 lists match for a given header name, no such header is added. For
9484 # do not debug transactions except for those that need debugging
9485 adaptation_meta X-Debug 1 needs_debugging
9487 # log all transactions except for those that must remain secret
9488 adaptation_meta X-Log 1 !keep_secret
9490 # mark transactions from users in the "G 1" group
9491 adaptation_meta X-Authenticated-Groups "G 1" authed_as_G1
9493 The "value" parameter may be a regular squid.conf token or a "double
9494 quoted string". Within the quoted string, use backslash (\) to escape
9495 any character, which is currently only useful for escaping backslashes
9496 and double quotes. For example,
9497 "this string has one backslash (\\) and two \"quotes\""
9499 Used adaptation_meta header values may be logged via %note
9500 logformat code. If multiple adaptation_meta headers with the same name
9501 are used during master transaction lifetime, the header values are
9502 logged in the order they were used and duplicate values are ignored
9503 (only the first repeated value will be logged).
9509 LOC: Adaptation::Icap::TheConfig.repeat
9510 DEFAULT_IF_NONE: deny all
9512 This ACL determines which retriable ICAP transactions are
9513 retried. Transactions that received a complete ICAP response
9514 and did not have to consume or produce HTTP bodies to receive
9515 that response are usually retriable.
9517 icap_retry allow|deny [!]aclname ...
9519 Squid automatically retries some ICAP I/O timeouts and errors
9520 due to persistent connection race conditions.
9522 See also: icap_retry_limit
9525 NAME: icap_retry_limit
9528 LOC: Adaptation::Icap::TheConfig.repeat_limit
9530 DEFAULT_DOC: No retries are allowed.
9532 Limits the number of retries allowed.
9534 Communication errors due to persistent connection race
9535 conditions are unavoidable, automatically retried, and do not
9536 count against this limit.
9538 See also: icap_retry
9544 -----------------------------------------------------------------------------
9547 NAME: check_hostnames
9550 LOC: Config.onoff.check_hostnames
9552 For security and stability reasons Squid can check
9553 hostnames for Internet standard RFC compliance. If you want
9554 Squid to perform these checks turn this directive on.
9557 NAME: allow_underscore
9560 LOC: Config.onoff.allow_underscore
9562 Underscore characters is not strictly allowed in Internet hostnames
9563 but nevertheless used by many sites. Set this to off if you want
9564 Squid to be strict about the standard.
9565 This check is performed only when check_hostnames is set to on.
9568 NAME: dns_retransmit_interval
9571 LOC: Config.Timeout.idns_retransmit
9573 Initial retransmit interval for DNS queries. The interval is
9574 doubled each time all configured DNS servers have been tried.
9580 LOC: Config.Timeout.idns_query
9582 DNS Query timeout. If no response is received to a DNS query
9583 within this time all DNS servers for the queried domain
9584 are assumed to be unavailable.
9587 NAME: dns_packet_max
9589 DEFAULT_DOC: EDNS disabled
9591 LOC: Config.dns.packet_max
9593 Maximum number of bytes packet size to advertise via EDNS.
9594 Set to "none" to disable EDNS large packet support.
9596 For legacy reasons DNS UDP replies will default to 512 bytes which
9597 is too small for many responses. EDNS provides a means for Squid to
9598 negotiate receiving larger responses back immediately without having
9599 to failover with repeat requests. Responses larger than this limit
9600 will retain the old behaviour of failover to TCP DNS.
9602 Squid has no real fixed limit internally, but allowing packet sizes
9603 over 1500 bytes requires network jumbogram support and is usually not
9606 WARNING: The RFC also indicates that some older resolvers will reply
9607 with failure of the whole request if the extension is added. Some
9608 resolvers have already been identified which will reply with mangled
9609 EDNS response on occasion. Usually in response to many-KB jumbogram
9610 sizes being advertised by Squid.
9611 Squid will currently treat these both as an unable-to-resolve domain
9612 even if it would be resolvable without EDNS.
9619 DEFAULT_DOC: Search for single-label domain names is disabled.
9620 LOC: Config.onoff.res_defnames
9622 Normally the RES_DEFNAMES resolver option is disabled
9623 (see res_init(3)). This prevents caches in a hierarchy
9624 from interpreting single-component hostnames locally. To allow
9625 Squid to handle single-component names, enable this option.
9628 NAME: dns_multicast_local
9632 DEFAULT_DOC: Search for .local and .arpa names is disabled.
9633 LOC: Config.onoff.dns_mdns
9635 When set to on, Squid sends multicast DNS lookups on the local
9636 network for domains ending in .local and .arpa.
9637 This enables local servers and devices to be contacted in an
9638 ad-hoc or zero-configuration network environment.
9641 NAME: dns_nameservers
9644 DEFAULT_DOC: Use operating system definitions
9645 LOC: Config.dns.nameservers
9647 Use this if you want to specify a list of DNS name servers
9648 (IP addresses) to use instead of those given in your
9649 /etc/resolv.conf file.
9651 On Windows platforms, if no value is specified here or in
9652 the /etc/resolv.conf file, the list of DNS name servers are
9653 taken from the Windows registry, both static and dynamic DHCP
9654 configurations are supported.
9656 Example: dns_nameservers 10.0.0.1 192.172.0.4
9661 DEFAULT: @DEFAULT_HOSTS@
9662 LOC: Config.etcHostsPath
9664 Location of the host-local IP name-address associations
9665 database. Most Operating Systems have such a file on different
9667 - Un*X & Linux: /etc/hosts
9668 - Windows NT/2000: %SystemRoot%\system32\drivers\etc\hosts
9669 (%SystemRoot% value install default is c:\winnt)
9670 - Windows XP/2003: %SystemRoot%\system32\drivers\etc\hosts
9671 (%SystemRoot% value install default is c:\windows)
9672 - Windows 9x/Me: %windir%\hosts
9673 (%windir% value is usually c:\windows)
9674 - Cygwin: /etc/hosts
9676 The file contains newline-separated definitions, in the
9677 form ip_address_in_dotted_form name [name ...] names are
9678 whitespace-separated. Lines beginning with an hash (#)
9679 character are comments.
9681 The file is checked at startup and upon configuration.
9682 If set to 'none', it won't be checked.
9683 If append_domain is used, that domain will be added to
9684 domain-local (i.e. not containing any dot character) host
9690 LOC: Config.appendDomain
9692 DEFAULT_DOC: Use operating system definitions
9694 Appends local domain name to hostnames without any dots in
9695 them. append_domain must begin with a period.
9697 Be warned there are now Internet names with no dots in
9698 them using only top-domain names, so setting this may
9699 cause some Internet sites to become unavailable.
9702 append_domain .yourdomain.com
9705 NAME: ignore_unknown_nameservers
9707 LOC: Config.onoff.ignore_unknown_nameservers
9710 By default Squid checks that DNS responses are received
9711 from the same IP addresses they are sent to. If they
9712 don't match, Squid ignores the response and writes a warning
9713 message to cache.log. You can allow responses from unknown
9714 nameservers by setting this option to 'off'.
9720 LOC: Config.dns.v4_first
9722 With the IPv6 Internet being as fast or faster than IPv4 Internet
9723 for most networks Squid prefers to contact websites over IPv6.
9725 This option reverses the order of preference to make Squid contact
9726 dual-stack websites over IPv4 first. Squid will still perform both
9727 IPv6 and IPv4 DNS lookups before connecting.
9730 This option will restrict the situations under which IPv6
9731 connectivity is used (and tested). Hiding network problems
9732 which would otherwise be detected and warned about.
9736 COMMENT: (number of entries)
9739 LOC: Config.ipcache.size
9741 Maximum number of DNS IP cache entries.
9748 LOC: Config.ipcache.low
9755 LOC: Config.ipcache.high
9757 The size, low-, and high-water marks for the IP cache.
9760 NAME: fqdncache_size
9761 COMMENT: (number of entries)
9764 LOC: Config.fqdncache.size
9766 Maximum number of FQDN cache entries.
9771 -----------------------------------------------------------------------------
9774 NAME: configuration_includes_quoted_values
9776 TYPE: configuration_includes_quoted_values
9778 LOC: ConfigParser::RecognizeQuotedValues
9780 If set, Squid will recognize each "quoted string" after a configuration
9781 directive as a single parameter. The quotes are stripped before the
9782 parameter value is interpreted or used.
9783 See "Values with spaces, quotes, and other special characters"
9784 section for more details.
9791 LOC: Config.onoff.mem_pools
9793 If set, Squid will keep pools of allocated (but unused) memory
9794 available for future use. If memory is a premium on your
9795 system and you believe your malloc library outperforms Squid
9796 routines, disable this.
9799 NAME: memory_pools_limit
9803 LOC: Config.MemPools.limit
9805 Used only with memory_pools on:
9806 memory_pools_limit 50 MB
9808 If set to a non-zero value, Squid will keep at most the specified
9809 limit of allocated (but unused) memory in memory pools. All free()
9810 requests that exceed this limit will be handled by your malloc
9811 library. Squid does not pre-allocate any memory, just safe-keeps
9812 objects that otherwise would be free()d. Thus, it is safe to set
9813 memory_pools_limit to a reasonably high value even if your
9814 configuration will use less memory.
9816 If set to none, Squid will keep all memory it can. That is, there
9817 will be no limit on the total amount of memory used for safe-keeping.
9819 To disable memory allocation optimization, do not set
9820 memory_pools_limit to 0 or none. Set memory_pools to "off" instead.
9822 An overhead for maintaining memory pools is not taken into account
9823 when the limit is checked. This overhead is close to four bytes per
9824 object kept. However, pools may actually _save_ memory because of
9825 reduced memory thrashing in your malloc library.
9829 COMMENT: on|off|transparent|truncate|delete
9832 LOC: opt_forwarded_for
9834 If set to "on", Squid will append your client's IP address
9835 in the HTTP requests it forwards. By default it looks like:
9837 X-Forwarded-For: 192.1.2.3
9839 If set to "off", it will appear as
9841 X-Forwarded-For: unknown
9843 If set to "transparent", Squid will not alter the
9844 X-Forwarded-For header in any way.
9846 If set to "delete", Squid will delete the entire
9847 X-Forwarded-For header.
9849 If set to "truncate", Squid will remove all existing
9850 X-Forwarded-For entries, and place the client IP as the sole entry.
9853 NAME: cachemgr_passwd
9854 TYPE: cachemgrpasswd
9856 DEFAULT_DOC: No password. Actions which require password are denied.
9857 LOC: Config.passwd_list
9859 Specify passwords for cachemgr operations.
9861 Usage: cachemgr_passwd password action action ...
9863 Some valid actions are (see cache manager menu for a full list):
9903 * Indicates actions which will not be performed without a
9904 valid password, others can be performed if not listed here.
9906 To disable an action, set the password to "disable".
9907 To allow performing an action without a password, set the
9910 Use the keyword "all" to set the same password for all actions.
9913 cachemgr_passwd secret shutdown
9914 cachemgr_passwd lesssssssecret info stats/objects
9915 cachemgr_passwd disable all
9922 LOC: Config.onoff.client_db
9924 If you want to disable collecting per-client statistics,
9925 turn off client_db here.
9928 NAME: refresh_all_ims
9932 LOC: Config.onoff.refresh_all_ims
9934 When you enable this option, squid will always check
9935 the origin server for an update when a client sends an
9936 If-Modified-Since request. Many browsers use IMS
9937 requests when the user requests a reload, and this
9938 ensures those clients receive the latest version.
9940 By default (off), squid may return a Not Modified response
9941 based on the age of the cached version.
9944 NAME: reload_into_ims
9945 IFDEF: USE_HTTP_VIOLATIONS
9949 LOC: Config.onoff.reload_into_ims
9951 When you enable this option, client no-cache or ``reload''
9952 requests will be changed to If-Modified-Since requests.
9953 Doing this VIOLATES the HTTP standard. Enabling this
9954 feature could make you liable for problems which it
9957 see also refresh_pattern for a more selective approach.
9960 NAME: connect_retries
9962 LOC: Config.connect_retries
9964 DEFAULT_DOC: Do not retry failed connections.
9966 This sets the maximum number of connection attempts made for each
9967 TCP connection. The connect_retries attempts must all still
9968 complete within the connection timeout period.
9970 The default is not to re-try if the first connection attempt fails.
9971 The (not recommended) maximum is 10 tries.
9973 A warning message will be generated if it is set to a too-high
9974 value and the configured value will be over-ridden.
9976 Note: These re-tries are in addition to forward_max_tries
9977 which limit how many different addresses may be tried to find
9981 NAME: retry_on_error
9983 LOC: Config.retry.onerror
9986 If set to ON Squid will automatically retry requests when
9987 receiving an error response with status 403 (Forbidden),
9988 500 (Internal Error), 501 or 503 (Service not available).
9989 Status 502 and 504 (Gateway errors) are always retried.
9991 This is mainly useful if you are in a complex cache hierarchy to
9992 work around access control errors.
9994 NOTE: This retry will attempt to find another working destination.
9995 Which is different from the server which just failed.
9998 NAME: as_whois_server
10000 LOC: Config.as_whois_server
10001 DEFAULT: whois.ra.net
10003 WHOIS server to query for AS numbers. NOTE: AS numbers are
10004 queried only when Squid starts up, not for every request.
10009 LOC: Config.onoff.offline
10012 Enable this option and Squid will never try to validate cached
10016 NAME: uri_whitespace
10017 TYPE: uri_whitespace
10018 LOC: Config.uri_whitespace
10021 What to do with requests that have whitespace characters in the
10024 strip: The whitespace characters are stripped out of the URL.
10025 This is the behavior recommended by RFC2396 and RFC3986
10026 for tolerant handling of generic URI.
10027 NOTE: This is one difference between generic URI and HTTP URLs.
10029 deny: The request is denied. The user receives an "Invalid
10031 This is the behaviour recommended by RFC2616 for safe
10032 handling of HTTP request URL.
10034 allow: The request is allowed and the URI is not changed. The
10035 whitespace characters remain in the URI. Note the
10036 whitespace is passed to redirector processes if they
10038 Note this may be considered a violation of RFC2616
10039 request parsing where whitespace is prohibited in the
10042 encode: The request is allowed and the whitespace characters are
10043 encoded according to RFC1738.
10045 chop: The request is allowed and the URI is chopped at the
10049 NOTE the current Squid implementation of encode and chop violates
10050 RFC2616 by not using a 301 redirect after altering the URL.
10055 LOC: Config.chroot_dir
10058 Specifies a directory where Squid should do a chroot() while
10059 initializing. This also causes Squid to fully drop root
10060 privileges after initializing. This means, for example, if you
10061 use a HTTP port less than 1024 and try to reconfigure, you may
10062 get an error saying that Squid can not open the port.
10065 NAME: balance_on_multiple_ip
10067 LOC: Config.onoff.balance_on_multiple_ip
10070 Modern IP resolvers in squid sort lookup results by preferred access.
10071 By default squid will use these IP in order and only rotates to
10072 the next listed when the most preffered fails.
10074 Some load balancing servers based on round robin DNS have been
10075 found not to preserve user session state across requests
10076 to different IP addresses.
10078 Enabling this directive Squid rotates IP's per request.
10081 NAME: pipeline_prefetch
10082 TYPE: pipelinePrefetch
10083 LOC: Config.pipeline_max_prefetch
10085 DEFAULT_DOC: Do not pre-parse pipelined requests.
10087 HTTP clients may send a pipeline of 1+N requests to Squid using a
10088 single connection, without waiting for Squid to respond to the first
10089 of those requests. This option limits the number of concurrent
10090 requests Squid will try to handle in parallel. If set to N, Squid
10091 will try to receive and process up to 1+N requests on the same
10092 connection concurrently.
10094 Defaults to 0 (off) for bandwidth management and access logging
10097 NOTE: pipelining requires persistent connections to clients.
10099 WARNING: pipelining breaks NTLM and Negotiate/Kerberos authentication.
10102 NAME: high_response_time_warning
10105 LOC: Config.warnings.high_rptm
10107 DEFAULT_DOC: disabled.
10109 If the one-minute median response time exceeds this value,
10110 Squid prints a WARNING with debug level 0 to get the
10111 administrators attention. The value is in milliseconds.
10114 NAME: high_page_fault_warning
10116 LOC: Config.warnings.high_pf
10118 DEFAULT_DOC: disabled.
10120 If the one-minute average page fault rate exceeds this
10121 value, Squid prints a WARNING with debug level 0 to get
10122 the administrators attention. The value is in page faults
10126 NAME: high_memory_warning
10128 LOC: Config.warnings.high_memory
10129 IFDEF: HAVE_MSTATS&&HAVE_GNUMALLOC_H
10131 DEFAULT_DOC: disabled.
10133 If the memory usage (as determined by gnumalloc, if available and used)
10134 exceeds this amount, Squid prints a WARNING with debug level 0 to get
10135 the administrators attention.
10137 # TODO: link high_memory_warning to mempools?
10139 NAME: sleep_after_fork
10140 COMMENT: (microseconds)
10142 LOC: Config.sleep_after_fork
10145 When this is set to a non-zero value, the main Squid process
10146 sleeps the specified number of microseconds after a fork()
10147 system call. This sleep may help the situation where your
10148 system reports fork() failures due to lack of (virtual)
10149 memory. Note, however, if you have a lot of child
10150 processes, these sleep delays will add up and your
10151 Squid will not service requests for some amount of time
10152 until all the child processes have been started.
10153 On Windows value less then 1000 (1 milliseconds) are
10157 NAME: windows_ipaddrchangemonitor
10158 IFDEF: _SQUID_WINDOWS_
10162 LOC: Config.onoff.WIN32_IpAddrChangeMonitor
10164 On Windows Squid by default will monitor IP address changes and will
10165 reconfigure itself after any detected event. This is very useful for
10166 proxies connected to internet with dial-up interfaces.
10167 In some cases (a Proxy server acting as VPN gateway is one) it could be
10168 desiderable to disable this behaviour setting this to 'off'.
10169 Note: after changing this, Squid service must be restarted.
10174 IFDEF: USE_SQUID_EUI
10176 LOC: Eui::TheConfig.euiLookup
10178 Whether to lookup the EUI or MAC address of a connected client.
10181 NAME: max_filedescriptors max_filedesc
10184 DEFAULT_DOC: Use operating system limits set by ulimit.
10185 LOC: Config.max_filedescriptors
10187 Reduce the maximum number of filedescriptors supported below
10188 the usual operating system defaults.
10190 Remove from squid.conf to inherit the current ulimit setting.
10192 Note: Changing this requires a restart of Squid. Also
10193 not all I/O types supports large values (eg on Windows).
10196 NAME: force_request_body_continuation
10198 LOC: Config.accessList.forceRequestBodyContinuation
10200 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
10202 This option controls how Squid handles data upload requests from HTTP
10203 and FTP agents that require a "Please Continue" control message response
10204 to actually send the request body to Squid. It is mostly useful in
10205 adaptation environments.
10207 When Squid receives an HTTP request with an "Expect: 100-continue"
10208 header or an FTP upload command (e.g., STOR), Squid normally sends the
10209 request headers or FTP command information to an adaptation service (or
10210 peer) and waits for a response. Most adaptation services (and some
10211 broken peers) may not respond to Squid at that stage because they may
10212 decide to wait for the HTTP request body or FTP data transfer. However,
10213 that request body or data transfer may never come because Squid has not
10214 responded with the HTTP 100 or FTP 150 (Please Continue) control message
10215 to the request sender yet!
10217 An allow match tells Squid to respond with the HTTP 100 or FTP 150
10218 (Please Continue) control message on its own, before forwarding the
10219 request to an adaptation service or peer. Such a response usually forces
10220 the request sender to proceed with sending the body. A deny match tells
10221 Squid to delay that control response until the origin server confirms
10222 that the request body is needed. Delaying is the default behavior.
10225 NAME: server_pconn_for_nonretriable
10228 DEFAULT_DOC: Open new connections for forwarding requests Squid cannot retry safely.
10229 LOC: Config.accessList.serverPconnForNonretriable
10231 This option provides fine-grained control over persistent connection
10232 reuse when forwarding HTTP requests that Squid cannot retry. It is useful
10233 in environments where opening new connections is very expensive
10234 (e.g., all connections are secured with TLS with complex client and server
10235 certificate validation) and race conditions associated with persistent
10236 connections are very rare and/or only cause minor problems.
10238 HTTP prohibits retrying unsafe and non-idempotent requests (e.g., POST).
10239 Squid limitations also prohibit retrying all requests with bodies (e.g., PUT).
10240 By default, when forwarding such "risky" requests, Squid opens a new
10241 connection to the server or cache_peer, even if there is an idle persistent
10242 connection available. When Squid is configured to risk sending a non-retriable
10243 request on a previously used persistent connection, and the server closes
10244 the connection before seeing that risky request, the user gets an error response
10245 from Squid. In most cases, that error response will be HTTP 502 (Bad Gateway)
10246 with ERR_ZERO_SIZE_OBJECT or ERR_WRITE_ERROR (peer connection reset) error detail.
10248 If an allow rule matches, Squid reuses an available idle persistent connection
10249 (if any) for the request that Squid cannot retry. If a deny rule matches, then
10250 Squid opens a new connection for the request that Squid cannot retry.
10252 This option does not affect requests that Squid can retry. They will reuse idle
10253 persistent connections (if any).
10255 This clause only supports fast acl types.
10256 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
10259 acl SpeedIsWorthTheRisk method POST
10260 server_pconn_for_nonretriable allow SpeedIsWorthTheRisk
projects / thirdparty / squid.git / blob