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]
1033 acl aclname arp mac-address ... (xx:xx:xx:xx:xx:xx notation)
1035 # The 'arp' ACL code is not portable to all operating systems.
1036 # It works on Linux, Solaris, Windows, FreeBSD, and some other
1039 # NOTE: Squid can only determine the MAC/EUI address for IPv4
1040 # clients that are on the same subnet. If the client is on a
1041 # different subnet, then Squid cannot find out its address.
1043 # NOTE 2: IPv6 protocol does not contain ARP. MAC/EUI is either
1044 # encoded directly in the IPv6 address or not available.
1046 acl aclname clientside_mark mark[/mask] ...
1047 # matches CONNMARK of an accepted connection [fast]
1049 # mark and mask are unsigned integers (hex, octal, or decimal).
1050 # If multiple marks are given, then the ACL matches if at least
1053 # Uses netfilter-conntrack library.
1054 # Requires building Squid with --enable-linux-netfilter.
1056 # The client, various intermediaries, and Squid itself may set
1057 # CONNMARK at various times. The last CONNMARK set wins. This ACL
1058 # checks the mark present on an accepted connection or set by
1059 # Squid afterwards, depending on the ACL check timing. This ACL
1060 # effectively ignores any mark set by other agents after Squid has
1061 # accepted the connection.
1063 acl aclname srcdomain .foo.com ...
1064 # reverse lookup, from client IP [slow]
1065 acl aclname dstdomain [-n] .foo.com ...
1066 # Destination server from URL [fast]
1067 acl aclname srcdom_regex [-i] \.foo\.com ...
1068 # regex matching client name [slow]
1069 acl aclname dstdom_regex [-n] [-i] \.foo\.com ...
1070 # regex matching server [fast]
1072 # For dstdomain and dstdom_regex a reverse lookup is tried if a IP
1073 # based URL is used and no match is found. The name "none" is used
1074 # if the reverse lookup fails.
1076 acl aclname src_as number ...
1077 acl aclname dst_as number ...
1079 # Except for access control, AS numbers can be used for
1080 # routing of requests to specific caches. Here's an
1081 # example for routing all requests for AS#1241 and only
1082 # those to mycache.mydomain.net:
1083 # acl asexample dst_as 1241
1084 # cache_peer_access mycache.mydomain.net allow asexample
1085 # cache_peer_access mycache_mydomain.net deny all
1087 acl aclname peername myPeer ...
1089 # match against a named cache_peer entry
1090 # set unique name= on cache_peer lines for reliable use.
1092 acl aclname time [day-abbrevs] [h1:m1-h2:m2]
1102 # h1:m1 must be less than h2:m2
1104 acl aclname url_regex [-i] ^http:// ...
1105 # regex matching on whole URL [fast]
1106 acl aclname urllogin [-i] [^a-zA-Z0-9] ...
1107 # regex matching on URL login field
1108 acl aclname urlpath_regex [-i] \.gif$ ...
1109 # regex matching on URL path [fast]
1111 acl aclname port 80 70 21 0-1024... # destination TCP port [fast]
1113 acl aclname localport 3128 ... # TCP port the client connected to [fast]
1114 # NP: for interception mode this is usually '80'
1116 acl aclname myportname 3128 ... # *_port name [fast]
1118 acl aclname proto HTTP FTP ... # request protocol [fast]
1120 acl aclname method GET POST ... # HTTP request method [fast]
1122 acl aclname http_status 200 301 500- 400-403 ...
1123 # status code in reply [fast]
1125 acl aclname browser [-i] regexp ...
1126 # pattern match on User-Agent header (see also req_header below) [fast]
1128 acl aclname referer_regex [-i] regexp ...
1129 # pattern match on Referer header [fast]
1130 # Referer is highly unreliable, so use with care
1132 acl aclname ident username ...
1133 acl aclname ident_regex [-i] pattern ...
1134 # string match on ident output [slow]
1135 # use REQUIRED to accept any non-null ident.
1137 acl aclname proxy_auth [-i] username ...
1138 acl aclname proxy_auth_regex [-i] pattern ...
1139 # perform http authentication challenge to the client and match against
1140 # supplied credentials [slow]
1142 # takes a list of allowed usernames.
1143 # use REQUIRED to accept any valid username.
1145 # Will use proxy authentication in forward-proxy scenarios, and plain
1146 # http authenticaiton in reverse-proxy scenarios
1148 # NOTE: when a Proxy-Authentication header is sent but it is not
1149 # needed during ACL checking the username is NOT logged
1152 # NOTE: proxy_auth requires a EXTERNAL authentication program
1153 # to check username/password combinations (see
1154 # auth_param directive).
1156 # NOTE: proxy_auth can't be used in a transparent/intercepting proxy
1157 # as the browser needs to be configured for using a proxy in order
1158 # to respond to proxy authentication.
1160 acl aclname snmp_community string ...
1161 # A community string to limit access to your SNMP Agent [fast]
1164 # acl snmppublic snmp_community public
1166 acl aclname maxconn number
1167 # This will be matched when the client's IP address has
1168 # more than <number> TCP connections established. [fast]
1169 # NOTE: This only measures direct TCP links so X-Forwarded-For
1170 # indirect clients are not counted.
1172 acl aclname max_user_ip [-s] number
1173 # This will be matched when the user attempts to log in from more
1174 # than <number> different ip addresses. The authenticate_ip_ttl
1175 # parameter controls the timeout on the ip entries. [fast]
1176 # If -s is specified the limit is strict, denying browsing
1177 # from any further IP addresses until the ttl has expired. Without
1178 # -s Squid will just annoy the user by "randomly" denying requests.
1179 # (the counter is reset each time the limit is reached and a
1180 # request is denied)
1181 # NOTE: in acceleration mode or where there is mesh of child proxies,
1182 # clients may appear to come from multiple addresses if they are
1183 # going through proxy farms, so a limit of 1 may cause user problems.
1185 acl aclname random probability
1186 # Pseudo-randomly match requests. Based on the probability given.
1187 # Probability may be written as a decimal (0.333), fraction (1/3)
1188 # or ratio of matches:non-matches (3:5).
1190 acl aclname req_mime_type [-i] mime-type ...
1191 # regex match against the mime type of the request generated
1192 # by the client. Can be used to detect file upload or some
1193 # types HTTP tunneling requests [fast]
1194 # NOTE: This does NOT match the reply. You cannot use this
1195 # to match the returned file type.
1197 acl aclname req_header header-name [-i] any\.regex\.here
1198 # regex match against any of the known request headers. May be
1199 # thought of as a superset of "browser", "referer" and "mime-type"
1202 acl aclname rep_mime_type [-i] mime-type ...
1203 # regex match against the mime type of the reply received by
1204 # squid. Can be used to detect file download or some
1205 # types HTTP tunneling requests. [fast]
1206 # NOTE: This has no effect in http_access rules. It only has
1207 # effect in rules that affect the reply data stream such as
1208 # http_reply_access.
1210 acl aclname rep_header header-name [-i] any\.regex\.here
1211 # regex match against any of the known reply headers. May be
1212 # thought of as a superset of "browser", "referer" and "mime-type"
1215 acl aclname external class_name [arguments...]
1216 # external ACL lookup via a helper class defined by the
1217 # external_acl_type directive [slow]
1219 acl aclname user_cert attribute values...
1220 # match against attributes in a user SSL certificate
1221 # attribute is one of DN/C/O/CN/L/ST or a numerical OID [fast]
1223 acl aclname ca_cert attribute values...
1224 # match against attributes a users issuing CA SSL certificate
1225 # attribute is one of DN/C/O/CN/L/ST or a numerical OID [fast]
1227 acl aclname ext_user username ...
1228 acl aclname ext_user_regex [-i] pattern ...
1229 # string match on username returned by external acl helper [slow]
1230 # use REQUIRED to accept any non-null user name.
1232 acl aclname tag tagvalue ...
1233 # string match on tag returned by external acl helper [fast]
1234 # DEPRECATED. Only the first tag will match with this ACL.
1235 # Use the 'note' ACL instead for handling multiple tag values.
1237 acl aclname hier_code codename ...
1238 # string match against squid hierarchy code(s); [fast]
1239 # e.g., DIRECT, PARENT_HIT, NONE, etc.
1241 # NOTE: This has no effect in http_access rules. It only has
1242 # effect in rules that affect the reply data stream such as
1243 # http_reply_access.
1245 acl aclname note [-m[=delimiters]] name [value ...]
1246 # match transaction annotation [fast]
1247 # Without values, matches any annotation with a given name.
1248 # With value(s), matches any annotation with a given name that
1249 # also has one of the given values.
1250 # If the -m flag is used, then the value of the named
1251 # annotation is interpreted as a list of tokens, and the ACL
1252 # matches individual name=token pairs rather than whole
1253 # name=value pairs. See "ACL Options" above for more info.
1254 # Annotation sources include note and adaptation_meta directives
1255 # as well as helper and eCAP responses.
1257 acl aclname annotate_transaction [-m[=delimiters]] key=value ...
1258 acl aclname annotate_transaction [-m[=delimiters]] key+=value ...
1259 # Always matches. [fast]
1260 # Used for its side effect: This ACL immediately adds a
1261 # key=value annotation to the current master transaction.
1262 # The added annotation can then be tested using note ACL and
1263 # logged (or sent to helpers) using %note format code.
1265 # Annotations can be specified using replacement and addition
1266 # formats. The key=value form replaces old same-key annotation
1267 # value(s). The key+=value form appends a new value to the old
1268 # same-key annotation. Both forms create a new key=value
1269 # annotation if no same-key annotation exists already. If
1270 # -m flag is used, then the value is interpreted as a list
1271 # and the annotation will contain key=token pair(s) instead of the
1272 # whole key=value pair.
1274 # This ACL is especially useful for recording complex multi-step
1275 # ACL-driven decisions. For example, the following configuration
1276 # avoids logging transactions accepted after aclX matched:
1278 # # First, mark transactions accepted after aclX matched
1279 # acl markSpecial annotate_transaction special=true
1280 # http_access allow acl001
1282 # http_access deny acl100
1283 # http_access allow aclX markSpecial
1285 # # Second, do not log marked transactions:
1286 # acl markedSpecial note special true
1287 # access_log ... deny markedSpecial
1289 # # Note that the following would not have worked because aclX
1290 # # alone does not determine whether the transaction was allowed:
1291 # access_log ... deny aclX # Wrong!
1293 # Warning: This ACL annotates the transaction even when negated
1294 # and even if subsequent ACLs fail to match. For example, the
1295 # following three rules will have exactly the same effect as far
1296 # as annotations set by the "mark" ACL are concerned:
1298 # some_directive acl1 ... mark # rule matches if mark is reached
1299 # some_directive acl1 ... !mark # rule never matches
1300 # some_directive acl1 ... mark !all # rule never matches
1302 acl aclname annotate_client [-m[=delimiters]] key=value ...
1303 acl aclname annotate_client [-m[=delimiters]] key+=value ...
1305 # Always matches. [fast]
1306 # Used for its side effect: This ACL immediately adds a
1307 # key=value annotation to the current client-to-Squid
1308 # connection. Connection annotations are propagated to the current
1309 # and all future master transactions on the annotated connection.
1310 # See the annotate_transaction ACL for details.
1312 # For example, the following configuration avoids rewriting URLs
1313 # of transactions bumped by SslBump:
1315 # # First, mark bumped connections:
1316 # acl markBumped annotate_client bumped=true
1317 # ssl_bump peek acl1
1318 # ssl_bump stare acl2
1319 # ssl_bump bump acl3 markBumped
1320 # ssl_bump splice all
1322 # # Second, do not send marked transactions to the redirector:
1323 # acl markedBumped note bumped true
1324 # url_rewrite_access deny markedBumped
1326 # # Note that the following would not have worked because acl3 alone
1327 # # does not determine whether the connection is going to be bumped:
1328 # url_rewrite_access deny acl3 # Wrong!
1330 acl aclname adaptation_service service ...
1331 # Matches the name of any icap_service, ecap_service,
1332 # adaptation_service_set, or adaptation_service_chain that Squid
1333 # has used (or attempted to use) for the master transaction.
1334 # This ACL must be defined after the corresponding adaptation
1335 # service is named in squid.conf. This ACL is usable with
1336 # adaptation_meta because it starts matching immediately after
1337 # the service has been selected for adaptation.
1339 acl aclname transaction_initiator initiator ...
1340 # Matches transaction's initiator [fast]
1342 # Supported initiators are:
1343 # esi: matches transactions fetching ESI resources
1344 # certificate-fetching: matches transactions fetching
1345 # a missing intermediate TLS certificate
1346 # cache-digest: matches transactions fetching Cache Digests
1348 # htcp: matches HTCP requests from peers
1349 # icp: matches ICP requests to peers
1350 # icmp: matches ICMP RTT database (NetDB) requests to peers
1351 # asn: matches asns db requests
1352 # internal: matches any of the above
1353 # client: matches transactions containing an HTTP or FTP
1354 # client request received at a Squid *_port
1355 # all: matches any transaction, including internal transactions
1356 # without a configurable initiator and hopefully rare
1357 # transactions without a known-to-Squid initiator
1359 # Multiple initiators are ORed.
1361 acl aclname has component
1362 # matches a transaction "component" [fast]
1364 # Supported transaction components are:
1365 # request: transaction has a request header (at least)
1366 # response: transaction has a response header (at least)
1367 # ALE: transaction has an internally-generated Access Log Entry
1368 # structure; bugs notwithstanding, all transaction have it
1370 # For example, the following configuration helps when dealing with HTTP
1371 # clients that close connections without sending a request header:
1373 # acl hasRequest has request
1374 # acl logMe note important_transaction
1375 # # avoid "logMe ACL is used in context without an HTTP request" warnings
1376 # access_log ... logformat=detailed hasRequest logMe
1377 # # log request-less transactions, instead of ignoring them
1378 # access_log ... logformat=brief !hasRequest
1380 # Multiple components are not supported for one "acl" rule, but
1381 # can be specified (and are ORed) using multiple same-name rules:
1383 # # OK, this strange logging daemon needs request or response,
1384 # # but can work without either a request or a response:
1385 # acl hasWhatMyLoggingDaemonNeeds has request
1386 # acl hasWhatMyLoggingDaemonNeeds has response
1389 acl aclname ssl_error errorname
1390 # match against SSL certificate validation error [fast]
1392 # For valid error names see in @DEFAULT_ERROR_DIR@/templates/error-details.txt
1395 # The following can be used as shortcuts for certificate properties:
1396 # [ssl::]certHasExpired: the "not after" field is in the past
1397 # [ssl::]certNotYetValid: the "not before" field is in the future
1398 # [ssl::]certUntrusted: The certificate issuer is not to be trusted.
1399 # [ssl::]certSelfSigned: The certificate is self signed.
1400 # [ssl::]certDomainMismatch: The certificate CN domain does not
1401 # match the name the name of the host we are connecting to.
1403 # The ssl::certHasExpired, ssl::certNotYetValid, ssl::certDomainMismatch,
1404 # ssl::certUntrusted, and ssl::certSelfSigned can also be used as
1405 # predefined ACLs, just like the 'all' ACL.
1407 # NOTE: The ssl_error ACL is only supported with sslproxy_cert_error,
1408 # sslproxy_cert_sign, and sslproxy_cert_adapt options.
1410 acl aclname server_cert_fingerprint [-sha1] fingerprint
1411 # match against server SSL certificate fingerprint [fast]
1413 # The fingerprint is the digest of the DER encoded version
1414 # of the whole certificate. The user should use the form: XX:XX:...
1415 # Optional argument specifies the digest algorithm to use.
1416 # The SHA1 digest algorithm is the default and is currently
1417 # the only algorithm supported (-sha1).
1419 acl aclname at_step step
1420 # match against the current step during ssl_bump evaluation [fast]
1421 # Never matches and should not be used outside the ssl_bump context.
1423 # At each SslBump step, Squid evaluates ssl_bump directives to find
1424 # the next bumping action (e.g., peek or splice). Valid SslBump step
1425 # values and the corresponding ssl_bump evaluation moments are:
1426 # SslBump1: After getting TCP-level and HTTP CONNECT info.
1427 # SslBump2: After getting SSL Client Hello info.
1428 # SslBump3: After getting SSL Server Hello info.
1430 acl aclname ssl::server_name [option] .foo.com ...
1431 # matches server name obtained from various sources [fast]
1433 # The ACL computes server name(s) using such information sources as
1434 # CONNECT request URI, TLS client SNI, and TLS server certificate
1435 # subject (CN and SubjectAltName). The computed server name(s) usually
1436 # change with each SslBump step, as more info becomes available:
1437 # * SNI is used as the server name instead of the request URI,
1438 # * subject name(s) from the server certificate (CN and
1439 # SubjectAltName) are used as the server names instead of SNI.
1441 # When the ACL computes multiple server names, matching any single
1442 # computed name is sufficient for the ACL to match.
1444 # The "none" name can be used to match transactions where the ACL
1445 # could not compute the server name using any information source
1446 # that was both available and allowed to be used by the ACL options at
1447 # the ACL evaluation time.
1449 # Unlike dstdomain, this ACL does not perform DNS lookups.
1451 # An ACL option below may be used to restrict what information
1452 # sources are used to extract the server names from:
1454 # --client-requested
1455 # The server name is SNI regardless of what the server says.
1457 # The server name(s) are the certificate subject name(s), regardless
1458 # of what the client has requested. If the server certificate is
1459 # unavailable, then the name is "none".
1461 # The server name is either SNI (if SNI matches at least one of the
1462 # certificate subject names) or "none" (otherwise). When the server
1463 # certificate is unavailable, the consensus server name is SNI.
1465 # Combining multiple options in one ACL is a fatal configuration
1468 # For all options: If no SNI is available, then the CONNECT request
1469 # target (a.k.a. URI) is used instead of SNI (for an intercepted
1470 # connection, this target is the destination IP address).
1472 acl aclname ssl::server_name_regex [-i] \.foo\.com ...
1473 # regex matches server name obtained from various sources [fast]
1475 acl aclname connections_encrypted
1476 # matches transactions with all HTTP messages received over TLS
1477 # transport connections. [fast]
1479 # The master transaction deals with HTTP messages received from
1480 # various sources. All sources used by the master transaction in the
1481 # past are considered by the ACL. The following rules define whether
1482 # a given message source taints the entire master transaction,
1483 # resulting in ACL mismatches:
1485 # * The HTTP client transport connection is not TLS.
1486 # * An adaptation service connection-encryption flag is off.
1487 # * The peer or origin server transport connection is not TLS.
1489 # Caching currently does not affect these rules. This cache ignorance
1490 # implies that only the current HTTP client transport and REQMOD
1491 # services status determine whether this ACL matches a from-cache
1492 # transaction. The source of the cached response does not have any
1493 # effect on future transaction that use the cached response without
1494 # revalidation. This may change.
1496 # DNS, ICP, and HTCP exchanges during the master transaction do not
1497 # affect these rules.
1499 acl aclname any-of acl1 acl2 ...
1500 # match any one of the acls [fast or slow]
1501 # The first matching ACL stops further ACL evaluation.
1503 # ACLs from multiple any-of lines with the same name are ORed.
1504 # For example, A = (a1 or a2) or (a3 or a4) can be written as
1505 # acl A any-of a1 a2
1506 # acl A any-of a3 a4
1508 # This group ACL is fast if all evaluated ACLs in the group are fast
1509 # and slow otherwise.
1511 acl aclname all-of acl1 acl2 ...
1512 # match all of the acls [fast or slow]
1513 # The first mismatching ACL stops further ACL evaluation.
1515 # ACLs from multiple all-of lines with the same name are ORed.
1516 # For example, B = (b1 and b2) or (b3 and b4) can be written as
1517 # acl B all-of b1 b2
1518 # acl B all-of b3 b4
1520 # This group ACL is fast if all evaluated ACLs in the group are fast
1521 # and slow otherwise.
1524 acl macaddress arp 09:00:2b:23:45:67
1525 acl myexample dst_as 1241
1526 acl password proxy_auth REQUIRED
1527 acl fileupload req_mime_type -i ^multipart/form-data$
1528 acl javascript rep_mime_type -i ^application/x-javascript$
1532 # Recommended minimum configuration:
1535 # Example rule allowing access from your local networks.
1536 # Adapt to list your (internal) IP networks from where browsing
1538 acl localnet src 0.0.0.1-0.255.255.255 # RFC 1122 "this" network (LAN)
1539 acl localnet src 10.0.0.0/8 # RFC 1918 local private network (LAN)
1540 acl localnet src 100.64.0.0/10 # RFC 6598 shared address space (CGN)
1541 acl localhet src 169.254.0.0/16 # RFC 3927 link-local (directly plugged) machines
1542 acl localnet src 172.16.0.0/12 # RFC 1918 local private network (LAN)
1543 acl localnet src 192.168.0.0/16 # RFC 1918 local private network (LAN)
1544 acl localnet src fc00::/7 # RFC 4193 local private network range
1545 acl localnet src fe80::/10 # RFC 4291 link-local (directly plugged) machines
1547 acl SSL_ports port 443
1548 acl Safe_ports port 80 # http
1549 acl Safe_ports port 21 # ftp
1550 acl Safe_ports port 443 # https
1551 acl Safe_ports port 70 # gopher
1552 acl Safe_ports port 210 # wais
1553 acl Safe_ports port 1025-65535 # unregistered ports
1554 acl Safe_ports port 280 # http-mgmt
1555 acl Safe_ports port 488 # gss-http
1556 acl Safe_ports port 591 # filemaker
1557 acl Safe_ports port 777 # multiling http
1561 NAME: proxy_protocol_access
1563 LOC: Config.accessList.proxyProtocol
1565 DEFAULT_DOC: all TCP connections to ports with require-proxy-header will be denied
1567 Determine which client proxies can be trusted to provide correct
1568 information regarding real client IP address using PROXY protocol.
1570 Requests may pass through a chain of several other proxies
1571 before reaching us. The original source details may by sent in:
1572 * HTTP message Forwarded header, or
1573 * HTTP message X-Forwarded-For header, or
1574 * PROXY protocol connection header.
1576 This directive is solely for validating new PROXY protocol
1577 connections received from a port flagged with require-proxy-header.
1578 It is checked only once after TCP connection setup.
1580 A deny match results in TCP connection closure.
1582 An allow match is required for Squid to permit the corresponding
1583 TCP connection, before Squid even looks for HTTP request headers.
1584 If there is an allow match, Squid starts using PROXY header information
1585 to determine the source address of the connection for all future ACL
1586 checks, logging, etc.
1588 SECURITY CONSIDERATIONS:
1590 Any host from which we accept client IP details can place
1591 incorrect information in the relevant header, and Squid
1592 will use the incorrect information as if it were the
1593 source address of the request. This may enable remote
1594 hosts to bypass any access control restrictions that are
1595 based on the client's source addresses.
1597 This clause only supports fast acl types.
1598 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1601 NAME: follow_x_forwarded_for
1603 IFDEF: FOLLOW_X_FORWARDED_FOR
1604 LOC: Config.accessList.followXFF
1605 DEFAULT_IF_NONE: deny all
1606 DEFAULT_DOC: X-Forwarded-For header will be ignored.
1608 Determine which client proxies can be trusted to provide correct
1609 information regarding real client IP address.
1611 Requests may pass through a chain of several other proxies
1612 before reaching us. The original source details may by sent in:
1613 * HTTP message Forwarded header, or
1614 * HTTP message X-Forwarded-For header, or
1615 * PROXY protocol connection header.
1617 PROXY protocol connections are controlled by the proxy_protocol_access
1618 directive which is checked before this.
1620 If a request reaches us from a source that is allowed by this
1621 directive, then we trust the information it provides regarding
1622 the IP of the client it received from (if any).
1624 For the purpose of ACLs used in this directive the src ACL type always
1625 matches the address we are testing and srcdomain matches its rDNS.
1627 On each HTTP request Squid checks for X-Forwarded-For header fields.
1628 If found the header values are iterated in reverse order and an allow
1629 match is required for Squid to continue on to the next value.
1630 The verification ends when a value receives a deny match, cannot be
1631 tested, or there are no more values to test.
1632 NOTE: Squid does not yet follow the Forwarded HTTP header.
1634 The end result of this process is an IP address that we will
1635 refer to as the indirect client address. This address may
1636 be treated as the client address for access control, ICAP, delay
1637 pools and logging, depending on the acl_uses_indirect_client,
1638 icap_uses_indirect_client, delay_pool_uses_indirect_client,
1639 log_uses_indirect_client and tproxy_uses_indirect_client options.
1641 This clause only supports fast acl types.
1642 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1644 SECURITY CONSIDERATIONS:
1646 Any host from which we accept client IP details can place
1647 incorrect information in the relevant header, and Squid
1648 will use the incorrect information as if it were the
1649 source address of the request. This may enable remote
1650 hosts to bypass any access control restrictions that are
1651 based on the client's source addresses.
1655 acl localhost src 127.0.0.1
1656 acl my_other_proxy srcdomain .proxy.example.com
1657 follow_x_forwarded_for allow localhost
1658 follow_x_forwarded_for allow my_other_proxy
1661 NAME: acl_uses_indirect_client
1664 IFDEF: FOLLOW_X_FORWARDED_FOR
1666 LOC: Config.onoff.acl_uses_indirect_client
1668 Controls whether the indirect client address
1669 (see follow_x_forwarded_for) is used instead of the
1670 direct client address in acl matching.
1672 NOTE: maxconn ACL considers direct TCP links and indirect
1673 clients will always have zero. So no match.
1676 NAME: delay_pool_uses_indirect_client
1679 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_DELAY_POOLS
1681 LOC: Config.onoff.delay_pool_uses_indirect_client
1683 Controls whether the indirect client address
1684 (see follow_x_forwarded_for) is used instead of the
1685 direct client address in delay pools.
1688 NAME: log_uses_indirect_client
1691 IFDEF: FOLLOW_X_FORWARDED_FOR
1693 LOC: Config.onoff.log_uses_indirect_client
1695 Controls whether the indirect client address
1696 (see follow_x_forwarded_for) is used instead of the
1697 direct client address in the access log.
1700 NAME: tproxy_uses_indirect_client
1703 IFDEF: FOLLOW_X_FORWARDED_FOR&&LINUX_NETFILTER
1705 LOC: Config.onoff.tproxy_uses_indirect_client
1707 Controls whether the indirect client address
1708 (see follow_x_forwarded_for) is used instead of the
1709 direct client address when spoofing the outgoing client.
1711 This has no effect on requests arriving in non-tproxy
1714 SECURITY WARNING: Usage of this option is dangerous
1715 and should not be used trivially. Correct configuration
1716 of follow_x_forwarded_for with a limited set of trusted
1717 sources is required to prevent abuse of your proxy.
1720 NAME: spoof_client_ip
1722 LOC: Config.accessList.spoof_client_ip
1724 DEFAULT_DOC: Allow spoofing on all TPROXY traffic.
1726 Control client IP address spoofing of TPROXY traffic based on
1727 defined access lists.
1729 spoof_client_ip allow|deny [!]aclname ...
1731 If there are no "spoof_client_ip" lines present, the default
1732 is to "allow" spoofing of any suitable request.
1734 Note that the cache_peer "no-tproxy" option overrides this ACL.
1736 This clause supports fast acl types.
1737 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1742 LOC: Config.accessList.http
1743 DEFAULT_IF_NONE: deny all
1744 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1746 Allowing or Denying access based on defined access lists
1748 To allow or deny a message received on an HTTP, HTTPS, or FTP port:
1749 http_access allow|deny [!]aclname ...
1751 NOTE on default values:
1753 If there are no "access" lines present, the default is to deny
1756 If none of the "access" lines cause a match, the default is the
1757 opposite of the last line in the list. If the last line was
1758 deny, the default is allow. Conversely, if the last line
1759 is allow, the default will be deny. For these reasons, it is a
1760 good idea to have an "deny all" entry at the end of your access
1761 lists to avoid potential confusion.
1763 This clause supports both fast and slow acl types.
1764 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1769 # Recommended minimum Access Permission configuration:
1771 # Deny requests to certain unsafe ports
1772 http_access deny !Safe_ports
1774 # Deny CONNECT to other than secure SSL ports
1775 http_access deny CONNECT !SSL_ports
1777 # Only allow cachemgr access from localhost
1778 http_access allow localhost manager
1779 http_access deny manager
1781 # We strongly recommend the following be uncommented to protect innocent
1782 # web applications running on the proxy server who think the only
1783 # one who can access services on "localhost" is a local user
1784 #http_access deny to_localhost
1787 # INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS
1790 # Example rule allowing access from your local networks.
1791 # Adapt localnet in the ACL section to list your (internal) IP networks
1792 # from where browsing should be allowed
1793 http_access allow localnet
1794 http_access allow localhost
1796 # And finally deny all other access to this proxy
1797 http_access deny all
1801 NAME: adapted_http_access http_access2
1803 LOC: Config.accessList.adapted_http
1805 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1807 Allowing or Denying access based on defined access lists
1809 Essentially identical to http_access, but runs after redirectors
1810 and ICAP/eCAP adaptation. Allowing access control based on their
1813 If not set then only http_access is used.
1816 NAME: http_reply_access
1818 LOC: Config.accessList.reply
1820 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1822 Allow replies to client requests. This is complementary to http_access.
1824 http_reply_access allow|deny [!] aclname ...
1826 NOTE: if there are no access lines present, the default is to allow
1829 If none of the access lines cause a match the opposite of the
1830 last line will apply. Thus it is good practice to end the rules
1831 with an "allow all" or "deny all" entry.
1833 This clause supports both fast and slow acl types.
1834 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1839 LOC: Config.accessList.icp
1841 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1843 Allowing or Denying access to the ICP port based on defined
1846 icp_access allow|deny [!]aclname ...
1848 NOTE: The default if no icp_access lines are present is to
1849 deny all traffic. This default may cause problems with peers
1852 This clause only supports fast acl types.
1853 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1855 # Allow ICP queries from local networks only
1856 #icp_access allow localnet
1857 #icp_access deny all
1863 LOC: Config.accessList.htcp
1865 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1867 Allowing or Denying access to the HTCP port based on defined
1870 htcp_access allow|deny [!]aclname ...
1872 See also htcp_clr_access for details on access control for
1873 cache purge (CLR) HTCP messages.
1875 NOTE: The default if no htcp_access lines are present is to
1876 deny all traffic. This default may cause problems with peers
1877 using the htcp option.
1879 This clause only supports fast acl types.
1880 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1882 # Allow HTCP queries from local networks only
1883 #htcp_access allow localnet
1884 #htcp_access deny all
1887 NAME: htcp_clr_access
1890 LOC: Config.accessList.htcp_clr
1892 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1894 Allowing or Denying access to purge content using HTCP based
1895 on defined access lists.
1896 See htcp_access for details on general HTCP access control.
1898 htcp_clr_access allow|deny [!]aclname ...
1900 This clause only supports fast acl types.
1901 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1903 # Allow HTCP CLR requests from trusted peers
1904 acl htcp_clr_peer src 192.0.2.2 2001:DB8::2
1905 htcp_clr_access allow htcp_clr_peer
1906 htcp_clr_access deny all
1911 LOC: Config.accessList.miss
1913 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1915 Determines whether network access is permitted when satisfying a request.
1918 to force your neighbors to use you as a sibling instead of
1921 acl localclients src 192.0.2.0/24 2001:DB8::a:0/64
1922 miss_access deny !localclients
1923 miss_access allow all
1925 This means only your local clients are allowed to fetch relayed/MISS
1926 replies from the network and all other clients can only fetch cached
1929 The default for this setting allows all clients who passed the
1930 http_access rules to relay via this proxy.
1932 This clause only supports fast acl types.
1933 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1936 NAME: ident_lookup_access
1940 DEFAULT_DOC: Unless rules exist in squid.conf, IDENT is not fetched.
1941 LOC: Ident::TheConfig.identLookup
1943 A list of ACL elements which, if matched, cause an ident
1944 (RFC 931) lookup to be performed for this request. For
1945 example, you might choose to always perform ident lookups
1946 for your main multi-user Unix boxes, but not for your Macs
1947 and PCs. By default, ident lookups are not performed for
1950 To enable ident lookups for specific client addresses, you
1951 can follow this example:
1953 acl ident_aware_hosts src 198.168.1.0/24
1954 ident_lookup_access allow ident_aware_hosts
1955 ident_lookup_access deny all
1957 Only src type ACL checks are fully supported. A srcdomain
1958 ACL might work at times, but it will not always provide
1961 This clause only supports fast acl types.
1962 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1965 NAME: reply_body_max_size
1966 COMMENT: size [acl acl...]
1969 DEFAULT_DOC: No limit is applied.
1970 LOC: Config.ReplyBodySize
1972 This option specifies the maximum size of a reply body. It can be
1973 used to prevent users from downloading very large files, such as
1974 MP3's and movies. When the reply headers are received, the
1975 reply_body_max_size lines are processed, and the first line where
1976 all (if any) listed ACLs are true is used as the maximum body size
1979 This size is checked twice. First when we get the reply headers,
1980 we check the content-length value. If the content length value exists
1981 and is larger than the allowed size, the request is denied and the
1982 user receives an error message that says "the request or reply
1983 is too large." If there is no content-length, and the reply
1984 size exceeds this limit, the client's connection is just closed
1985 and they will receive a partial reply.
1987 WARNING: downstream caches probably can not detect a partial reply
1988 if there is no content-length header, so they will cache
1989 partial responses and give them out as hits. You should NOT
1990 use this option if you have downstream caches.
1992 WARNING: A maximum size smaller than the size of squid's error messages
1993 will cause an infinite loop and crash squid. Ensure that the smallest
1994 non-zero value you use is greater that the maximum header size plus
1995 the size of your largest error page.
1997 If you set this parameter none (the default), there will be
2000 Configuration Format is:
2001 reply_body_max_size SIZE UNITS [acl ...]
2003 reply_body_max_size 10 MB
2007 NAME: on_unsupported_protocol
2008 TYPE: on_unsupported_protocol
2009 LOC: Config.accessList.on_unsupported_protocol
2011 DEFAULT_DOC: Respond with an error message to unidentifiable traffic
2013 Determines Squid behavior when encountering strange requests at the
2014 beginning of an accepted TCP connection or the beginning of a bumped
2015 CONNECT tunnel. Controlling Squid reaction to unexpected traffic is
2016 especially useful in interception environments where Squid is likely
2017 to see connections for unsupported protocols that Squid should either
2018 terminate or tunnel at TCP level.
2020 on_unsupported_protocol <action> [!]acl ...
2022 The first matching action wins. Only fast ACLs are supported.
2024 Supported actions are:
2026 tunnel: Establish a TCP connection with the intended server and
2027 blindly shovel TCP packets between the client and server.
2029 respond: Respond with an error message, using the transfer protocol
2030 for the Squid port that received the request (e.g., HTTP
2031 for connections intercepted at the http_port). This is the
2034 Squid expects the following traffic patterns:
2036 http_port: a plain HTTP request
2037 https_port: SSL/TLS handshake followed by an [encrypted] HTTP request
2038 ftp_port: a plain FTP command (no on_unsupported_protocol support yet!)
2039 CONNECT tunnel on http_port: same as https_port
2040 CONNECT tunnel on https_port: same as https_port
2042 Currently, this directive has effect on intercepted connections and
2043 bumped tunnels only. Other cases are not supported because Squid
2044 cannot know the intended destination of other traffic.
2047 # define what Squid errors indicate receiving non-HTTP traffic:
2048 acl foreignProtocol squid_error ERR_PROTOCOL_UNKNOWN ERR_TOO_BIG
2049 # define what Squid errors indicate receiving nothing:
2050 acl serverTalksFirstProtocol squid_error ERR_REQUEST_START_TIMEOUT
2051 # tunnel everything that does not look like HTTP:
2052 on_unsupported_protocol tunnel foreignProtocol
2053 # tunnel if we think the client waits for the server to talk first:
2054 on_unsupported_protocol tunnel serverTalksFirstProtocol
2055 # in all other error cases, just send an HTTP "error page" response:
2056 on_unsupported_protocol respond all
2058 See also: squid_error ACL
2064 LOC: Auth::TheConfig.schemeAccess
2066 DEFAULT_DOC: use all auth_param schemes in their configuration order
2068 Use this directive to customize authentication schemes presence and
2069 order in Squid's Unauthorized and Authentication Required responses.
2071 auth_schemes scheme1,scheme2,... [!]aclname ...
2073 where schemeN is the name of one of the authentication schemes
2074 configured using auth_param directives. At least one scheme name is
2075 required. Multiple scheme names are separated by commas. Either
2076 avoid whitespace or quote the entire schemes list.
2078 A special "ALL" scheme name expands to all auth_param-configured
2079 schemes in their configuration order. This directive cannot be used
2080 to configure Squid to offer no authentication schemes at all.
2082 The first matching auth_schemes rule determines the schemes order
2083 for the current Authentication Required transaction. Note that the
2084 future response is not yet available during auth_schemes evaluation.
2086 If this directive is not used or none of its rules match, then Squid
2087 responds with all configured authentication schemes in the order of
2088 auth_param directives in the configuration file.
2090 This directive does not determine when authentication is used or
2091 how each authentication scheme authenticates clients.
2093 The following example sends basic and negotiate authentication
2094 schemes, in that order, when requesting authentication of HTTP
2095 requests matching the isIE ACL (not shown) while sending all
2096 auth_param schemes in their configuration order to other clients:
2098 auth_schemes basic,negotiate isIE
2099 auth_schemes ALL all # explicit default
2101 This directive supports fast ACLs only.
2103 See also: auth_param.
2108 -----------------------------------------------------------------------------
2111 NAME: http_port ascii_port
2116 Usage: port [mode] [options]
2117 hostname:port [mode] [options]
2118 1.2.3.4:port [mode] [options]
2120 The socket addresses where Squid will listen for HTTP client
2121 requests. You may specify multiple socket addresses.
2122 There are three forms: port alone, hostname with port, and
2123 IP address with port. If you specify a hostname or IP
2124 address, Squid binds the socket to that specific
2125 address. Most likely, you do not need to bind to a specific
2126 address, so you can use the port number alone.
2128 If you are running Squid in accelerator mode, you
2129 probably want to listen on port 80 also, or instead.
2131 The -a command line option may be used to specify additional
2132 port(s) where Squid listens for proxy request. Such ports will
2133 be plain proxy ports with no options.
2135 You may specify multiple socket addresses on multiple lines.
2139 intercept Support for IP-Layer NAT interception delivering
2140 traffic to this Squid port.
2141 NP: disables authentication on the port.
2143 tproxy Support Linux TPROXY (or BSD divert-to) with spoofing
2144 of outgoing connections using the client IP address.
2145 NP: disables authentication on the port.
2147 accel Accelerator / reverse proxy mode
2149 ssl-bump For each CONNECT request allowed by ssl_bump ACLs,
2150 establish secure connection with the client and with
2151 the server, decrypt HTTPS messages as they pass through
2152 Squid, and treat them as unencrypted HTTP messages,
2153 becoming the man-in-the-middle.
2155 The ssl_bump option is required to fully enable
2156 bumping of CONNECT requests.
2158 Omitting the mode flag causes default forward proxy mode to be used.
2161 Accelerator Mode Options:
2163 defaultsite=domainname
2164 What to use for the Host: header if it is not present
2165 in a request. Determines what site (not origin server)
2166 accelerators should consider the default.
2168 no-vhost Disable using HTTP/1.1 Host header for virtual domain support.
2170 protocol= Protocol to reconstruct accelerated and intercepted
2171 requests with. Defaults to HTTP/1.1 for http_port and
2172 HTTPS/1.1 for https_port.
2173 When an unsupported value is configured Squid will
2174 produce a FATAL error.
2175 Values: HTTP or HTTP/1.1, HTTPS or HTTPS/1.1
2177 vport Virtual host port support. Using the http_port number
2178 instead of the port passed on Host: headers.
2180 vport=NN Virtual host port support. Using the specified port
2181 number instead of the port passed on Host: headers.
2184 Act as if this Squid is the origin server.
2185 This currently means generate new Date: and Expires:
2186 headers on HIT instead of adding Age:.
2188 ignore-cc Ignore request Cache-Control headers.
2190 WARNING: This option violates HTTP specifications if
2191 used in non-accelerator setups.
2193 allow-direct Allow direct forwarding in accelerator mode. Normally
2194 accelerated requests are denied direct forwarding as if
2195 never_direct was used.
2197 WARNING: this option opens accelerator mode to security
2198 vulnerabilities usually only affecting in interception
2199 mode. Make sure to protect forwarding with suitable
2200 http_access rules when using this.
2203 SSL Bump Mode Options:
2204 In addition to these options ssl-bump requires TLS/SSL options.
2206 generate-host-certificates[=<on|off>]
2207 Dynamically create SSL server certificates for the
2208 destination hosts of bumped CONNECT requests.When
2209 enabled, the cert and key options are used to sign
2210 generated certificates. Otherwise generated
2211 certificate will be selfsigned.
2212 If there is a CA certificate lifetime of the generated
2213 certificate equals lifetime of the CA certificate. If
2214 generated certificate is selfsigned lifetime is three
2216 This option is enabled by default when ssl-bump is used.
2217 See the ssl-bump option above for more information.
2219 dynamic_cert_mem_cache_size=SIZE
2220 Approximate total RAM size spent on cached generated
2221 certificates. If set to zero, caching is disabled. The
2222 default value is 4MB.
2226 tls-cert= Path to file containing an X.509 certificate (PEM format)
2227 to be used in the TLS handshake ServerHello.
2229 If this certificate is constrained by KeyUsage TLS
2230 feature it must allow HTTP server usage, along with
2231 any additional restrictions imposed by your choice
2232 of options= settings.
2234 When OpenSSL is used this file may also contain a
2235 chain of intermediate CA certificates to send in the
2238 When GnuTLS is used this option (and any paired
2239 tls-key= option) may be repeated to load multiple
2240 certificates for different domains.
2242 Also, when generate-host-certificates=on is configured
2243 the first tls-cert= option must be a CA certificate
2244 capable of signing the automatically generated
2247 tls-key= Path to a file containing private key file (PEM format)
2248 for the previous tls-cert= option.
2250 If tls-key= is not specified tls-cert= is assumed to
2251 reference a PEM file containing both the certificate
2254 cipher= Colon separated list of supported ciphers.
2255 NOTE: some ciphers such as EDH ciphers depend on
2256 additional settings. If those settings are
2257 omitted the ciphers may be silently ignored
2258 by the OpenSSL library.
2260 options= Various SSL implementation options. The most important
2263 NO_SSLv3 Disallow the use of SSLv3
2265 NO_TLSv1 Disallow the use of TLSv1.0
2267 NO_TLSv1_1 Disallow the use of TLSv1.1
2269 NO_TLSv1_2 Disallow the use of TLSv1.2
2272 Always create a new key when using
2273 temporary/ephemeral DH key exchanges
2276 Enable ephemeral ECDH key exchange.
2277 The adopted curve should be specified
2278 using the tls-dh option.
2281 Disable use of RFC5077 session tickets.
2282 Some servers may have problems
2283 understanding the TLS extension due
2284 to ambiguous specification in RFC4507.
2286 ALL Enable various bug workarounds
2287 suggested as "harmless" by OpenSSL
2288 Be warned that this reduces SSL/TLS
2289 strength to some attacks.
2291 See the OpenSSL SSL_CTX_set_options documentation for a
2294 clientca= File containing the list of CAs to use when
2295 requesting a client certificate.
2297 tls-cafile= PEM file containing CA certificates to use when verifying
2298 client certificates. If not configured clientca will be
2299 used. May be repeated to load multiple files.
2301 capath= Directory containing additional CA certificates
2302 and CRL lists to use when verifying client certificates.
2303 Requires OpenSSL or LibreSSL.
2305 crlfile= File of additional CRL lists to use when verifying
2306 the client certificate, in addition to CRLs stored in
2307 the capath. Implies VERIFY_CRL flag below.
2310 File containing DH parameters for temporary/ephemeral DH key
2311 exchanges, optionally prefixed by a curve for ephemeral ECDH
2313 See OpenSSL documentation for details on how to create the
2314 DH parameter file. Supported curves for ECDH can be listed
2315 using the "openssl ecparam -list_curves" command.
2316 WARNING: EDH and EECDH ciphers will be silently disabled if
2317 this option is not set.
2319 sslflags= Various flags modifying the use of SSL:
2321 Don't request client certificates
2322 immediately, but wait until acl processing
2323 requires a certificate (not yet implemented).
2325 Don't allow for session reuse. Each connection
2326 will result in a new SSL session.
2328 Verify CRL lists when accepting client
2331 Verify CRL lists for all certificates in the
2332 client certificate chain.
2334 tls-default-ca[=off]
2335 Whether to use the system Trusted CAs. Default is OFF.
2337 tls-no-npn Do not use the TLS NPN extension to advertise HTTP/1.1.
2339 sslcontext= SSL session ID context identifier.
2343 connection-auth[=on|off]
2344 use connection-auth=off to tell Squid to prevent
2345 forwarding Microsoft connection oriented authentication
2346 (NTLM, Negotiate and Kerberos)
2348 disable-pmtu-discovery=
2349 Control Path-MTU discovery usage:
2350 off lets OS decide on what to do (default).
2351 transparent disable PMTU discovery when transparent
2353 always disable always PMTU discovery.
2355 In many setups of transparently intercepting proxies
2356 Path-MTU discovery can not work on traffic towards the
2357 clients. This is the case when the intercepting device
2358 does not fully track connections and fails to forward
2359 ICMP must fragment messages to the cache server. If you
2360 have such setup and experience that certain clients
2361 sporadically hang or never complete requests set
2362 disable-pmtu-discovery option to 'transparent'.
2364 name= Specifies a internal name for the port. Defaults to
2365 the port specification (port or addr:port)
2367 tcpkeepalive[=idle,interval,timeout]
2368 Enable TCP keepalive probes of idle connections.
2369 In seconds; idle is the initial time before TCP starts
2370 probing the connection, interval how often to probe, and
2371 timeout the time before giving up.
2373 require-proxy-header
2374 Require PROXY protocol version 1 or 2 connections.
2375 The proxy_protocol_access is required to whitelist
2376 downstream proxies which can be trusted.
2378 If you run Squid on a dual-homed machine with an internal
2379 and an external interface we recommend you to specify the
2380 internal address:port in http_port. This way Squid will only be
2381 visible on the internal address.
2385 # Squid normally listens to port 3128
2386 http_port @DEFAULT_HTTP_PORT@
2391 IFDEF: USE_GNUTLS||USE_OPENSSL
2396 Usage: [ip:]port [mode] tls-cert=certificate.pem [options]
2398 The socket address where Squid will listen for client requests made
2399 over TLS or SSL connections. Commonly referred to as HTTPS.
2401 This is most useful for situations where you are running squid in
2402 accelerator mode and you want to do the TLS work at the accelerator
2405 You may specify multiple socket addresses on multiple lines,
2406 each with their own certificate and/or options.
2408 The tls-cert= option is mandatory on HTTPS ports.
2410 See http_port for a list of modes and options.
2418 Enables Native FTP proxy by specifying the socket address where Squid
2419 listens for FTP client requests. See http_port directive for various
2420 ways to specify the listening address and mode.
2422 Usage: ftp_port address [mode] [options]
2424 WARNING: This is a new, experimental, complex feature that has seen
2425 limited production exposure. Some Squid modules (e.g., caching) do not
2426 currently work with native FTP proxying, and many features have not
2427 even been tested for compatibility. Test well before deploying!
2429 Native FTP proxying differs substantially from proxying HTTP requests
2430 with ftp:// URIs because Squid works as an FTP server and receives
2431 actual FTP commands (rather than HTTP requests with FTP URLs).
2433 Native FTP commands accepted at ftp_port are internally converted or
2434 wrapped into HTTP-like messages. The same happens to Native FTP
2435 responses received from FTP origin servers. Those HTTP-like messages
2436 are shoveled through regular access control and adaptation layers
2437 between the FTP client and the FTP origin server. This allows Squid to
2438 examine, adapt, block, and log FTP exchanges. Squid reuses most HTTP
2439 mechanisms when shoveling wrapped FTP messages. For example,
2440 http_access and adaptation_access directives are used.
2444 intercept Same as http_port intercept. The FTP origin address is
2445 determined based on the intended destination of the
2446 intercepted connection.
2448 tproxy Support Linux TPROXY for spoofing outgoing
2449 connections using the client IP address.
2450 NP: disables authentication and maybe IPv6 on the port.
2452 By default (i.e., without an explicit mode option), Squid extracts the
2453 FTP origin address from the login@origin parameter of the FTP USER
2454 command. Many popular FTP clients support such native FTP proxying.
2458 name=token Specifies an internal name for the port. Defaults to
2459 the port address. Usable with myportname ACL.
2462 Enables tracking of FTP directories by injecting extra
2463 PWD commands and adjusting Request-URI (in wrapping
2464 HTTP requests) to reflect the current FTP server
2465 directory. Tracking is disabled by default.
2467 protocol=FTP Protocol to reconstruct accelerated and intercepted
2468 requests with. Defaults to FTP. No other accepted
2469 values have been tested with. An unsupported value
2470 results in a FATAL error. Accepted values are FTP,
2471 HTTP (or HTTP/1.1), and HTTPS (or HTTPS/1.1).
2473 Other http_port modes and options that are not specific to HTTP and
2474 HTTPS may also work.
2477 NAME: tcp_outgoing_tos tcp_outgoing_ds tcp_outgoing_dscp
2480 LOC: Ip::Qos::TheConfig.tosToServer
2482 Allows you to select a TOS/Diffserv value for packets outgoing
2483 on the server side, based on an ACL.
2485 tcp_outgoing_tos ds-field [!]aclname ...
2487 Example where normal_service_net uses the TOS value 0x00
2488 and good_service_net uses 0x20
2490 acl normal_service_net src 10.0.0.0/24
2491 acl good_service_net src 10.0.1.0/24
2492 tcp_outgoing_tos 0x00 normal_service_net
2493 tcp_outgoing_tos 0x20 good_service_net
2495 TOS/DSCP values really only have local significance - so you should
2496 know what you're specifying. For more information, see RFC2474,
2497 RFC2475, and RFC3260.
2499 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
2500 "default" to use whatever default your host has.
2501 Note that only multiples of 4 are usable as the two rightmost bits have
2502 been redefined for use by ECN (RFC 3168 section 23.1).
2503 The squid parser will enforce this by masking away the ECN bits.
2505 Processing proceeds in the order specified, and stops at first fully
2508 Only fast ACLs are supported.
2511 NAME: clientside_tos
2514 LOC: Ip::Qos::TheConfig.tosToClient
2516 Allows you to select a TOS/DSCP value for packets being transmitted
2517 on the client-side, based on an ACL.
2519 clientside_tos ds-field [!]aclname ...
2521 Example where normal_service_net uses the TOS value 0x00
2522 and good_service_net uses 0x20
2524 acl normal_service_net src 10.0.0.0/24
2525 acl good_service_net src 10.0.1.0/24
2526 clientside_tos 0x00 normal_service_net
2527 clientside_tos 0x20 good_service_net
2529 Note: This feature is incompatible with qos_flows. Any TOS values set here
2530 will be overwritten by TOS values in qos_flows.
2532 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
2533 "default" to use whatever default your host has.
2534 Note that only multiples of 4 are usable as the two rightmost bits have
2535 been redefined for use by ECN (RFC 3168 section 23.1).
2536 The squid parser will enforce this by masking away the ECN bits.
2538 This clause only supports fast acl types.
2539 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2542 NAME: tcp_outgoing_mark
2544 IFDEF: SO_MARK&&USE_LIBCAP
2546 LOC: Ip::Qos::TheConfig.nfmarkToServer
2548 Allows you to apply a Netfilter mark value to outgoing packets
2549 on the server side, based on an ACL.
2551 tcp_outgoing_mark mark-value [!]aclname ...
2553 Example where normal_service_net uses the mark value 0x00
2554 and good_service_net uses 0x20
2556 acl normal_service_net src 10.0.0.0/24
2557 acl good_service_net src 10.0.1.0/24
2558 tcp_outgoing_mark 0x00 normal_service_net
2559 tcp_outgoing_mark 0x20 good_service_net
2561 Only fast ACLs are supported.
2564 NAME: clientside_mark
2566 IFDEF: SO_MARK&&USE_LIBCAP
2568 LOC: Ip::Qos::TheConfig.nfmarkToClient
2570 Allows you to apply a Netfilter mark value to packets being transmitted
2571 on the client-side, based on an ACL.
2573 clientside_mark mark-value [!]aclname ...
2575 Example where normal_service_net uses the mark value 0x00
2576 and good_service_net uses 0x20
2578 acl normal_service_net src 10.0.0.0/24
2579 acl good_service_net src 10.0.1.0/24
2580 clientside_mark 0x00 normal_service_net
2581 clientside_mark 0x20 good_service_net
2583 Note: This feature is incompatible with qos_flows. Any mark values set here
2584 will be overwritten by mark values in qos_flows.
2586 This clause only supports fast acl types.
2587 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2594 LOC: Ip::Qos::TheConfig
2596 Allows you to select a TOS/DSCP value to mark outgoing
2597 connections to the client, based on where the reply was sourced.
2598 For platforms using netfilter, allows you to set a netfilter mark
2599 value instead of, or in addition to, a TOS value.
2601 By default this functionality is disabled. To enable it with the default
2602 settings simply use "qos_flows mark" or "qos_flows tos". Default
2603 settings will result in the netfilter mark or TOS value being copied
2604 from the upstream connection to the client. Note that it is the connection
2605 CONNMARK value not the packet MARK value that is copied.
2607 It is not currently possible to copy the mark or TOS value from the
2608 client to the upstream connection request.
2610 TOS values really only have local significance - so you should
2611 know what you're specifying. For more information, see RFC2474,
2612 RFC2475, and RFC3260.
2614 The TOS/DSCP byte must be exactly that - a octet value 0 - 255.
2615 Note that only multiples of 4 are usable as the two rightmost bits have
2616 been redefined for use by ECN (RFC 3168 section 23.1).
2617 The squid parser will enforce this by masking away the ECN bits.
2619 Mark values can be any unsigned 32-bit integer value.
2621 This setting is configured by setting the following values:
2623 tos|mark Whether to set TOS or netfilter mark values
2625 local-hit=0xFF Value to mark local cache hits.
2627 sibling-hit=0xFF Value to mark hits from sibling peers.
2629 parent-hit=0xFF Value to mark hits from parent peers.
2631 miss=0xFF[/mask] Value to mark cache misses. Takes precedence
2632 over the preserve-miss feature (see below), unless
2633 mask is specified, in which case only the bits
2634 specified in the mask are written.
2636 The TOS variant of the following features are only possible on Linux
2637 and require your kernel to be patched with the TOS preserving ZPH
2638 patch, available from http://zph.bratcheda.org
2639 No patch is needed to preserve the netfilter mark, which will work
2640 with all variants of netfilter.
2642 disable-preserve-miss
2643 This option disables the preservation of the TOS or netfilter
2644 mark. By default, the existing TOS or netfilter mark value of
2645 the response coming from the remote server will be retained
2646 and masked with miss-mark.
2647 NOTE: in the case of a netfilter mark, the mark must be set on
2648 the connection (using the CONNMARK target) not on the packet
2652 Allows you to mask certain bits in the TOS or mark value
2653 received from the remote server, before copying the value to
2654 the TOS sent towards clients.
2655 Default for tos: 0xFF (TOS from server is not changed).
2656 Default for mark: 0xFFFFFFFF (mark from server is not changed).
2658 All of these features require the --enable-zph-qos compilation flag
2659 (enabled by default). Netfilter marking also requires the
2660 libnetfilter_conntrack libraries (--with-netfilter-conntrack) and
2661 libcap 2.09+ (--with-libcap).
2665 NAME: tcp_outgoing_address
2668 DEFAULT_DOC: Address selection is performed by the operating system.
2669 LOC: Config.accessList.outgoing_address
2671 Allows you to map requests to different outgoing IP addresses
2672 based on the username or source address of the user making
2675 tcp_outgoing_address ipaddr [[!]aclname] ...
2678 Forwarding clients with dedicated IPs for certain subnets.
2680 acl normal_service_net src 10.0.0.0/24
2681 acl good_service_net src 10.0.2.0/24
2683 tcp_outgoing_address 2001:db8::c001 good_service_net
2684 tcp_outgoing_address 10.1.0.2 good_service_net
2686 tcp_outgoing_address 2001:db8::beef normal_service_net
2687 tcp_outgoing_address 10.1.0.1 normal_service_net
2689 tcp_outgoing_address 2001:db8::1
2690 tcp_outgoing_address 10.1.0.3
2692 Processing proceeds in the order specified, and stops at first fully
2695 Squid will add an implicit IP version test to each line.
2696 Requests going to IPv4 websites will use the outgoing 10.1.0.* addresses.
2697 Requests going to IPv6 websites will use the outgoing 2001:db8:* addresses.
2700 NOTE: The use of this directive using client dependent ACLs is
2701 incompatible with the use of server side persistent connections. To
2702 ensure correct results it is best to set server_persistent_connections
2703 to off when using this directive in such configurations.
2705 NOTE: The use of this directive to set a local IP on outgoing TCP links
2706 is incompatible with using TPROXY to set client IP out outbound TCP links.
2707 When needing to contact peers use the no-tproxy cache_peer option and the
2708 client_dst_passthru directive re-enable normal forwarding such as this.
2710 This clause only supports fast acl types.
2711 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2714 NAME: host_verify_strict
2717 LOC: Config.onoff.hostStrictVerify
2719 Regardless of this option setting, when dealing with intercepted
2720 traffic, Squid always verifies that the destination IP address matches
2721 the Host header domain or IP (called 'authority form URL').
2723 This enforcement is performed to satisfy a MUST-level requirement in
2724 RFC 2616 section 14.23: "The Host field value MUST represent the naming
2725 authority of the origin server or gateway given by the original URL".
2728 Squid always responds with an HTTP 409 (Conflict) error
2729 page and logs a security warning if there is no match.
2731 Squid verifies that the destination IP address matches
2732 the Host header for forward-proxy and reverse-proxy traffic
2733 as well. For those traffic types, Squid also enables the
2734 following checks, comparing the corresponding Host header
2735 and Request-URI components:
2737 * The host names (domain or IP) must be identical,
2738 but valueless or missing Host header disables all checks.
2739 For the two host names to match, both must be either IP
2742 * Port numbers must be identical, but if a port is missing
2743 the scheme-default port is assumed.
2746 When set to OFF (the default):
2747 Squid allows suspicious requests to continue but logs a
2748 security warning and blocks caching of the response.
2750 * Forward-proxy traffic is not checked at all.
2752 * Reverse-proxy traffic is not checked at all.
2754 * Intercepted traffic which passes verification is handled
2755 according to client_dst_passthru.
2757 * Intercepted requests which fail verification are sent
2758 to the client original destination instead of DIRECT.
2759 This overrides 'client_dst_passthru off'.
2761 For now suspicious intercepted CONNECT requests are always
2762 responded to with an HTTP 409 (Conflict) error page.
2767 As described in CVE-2009-0801 when the Host: header alone is used
2768 to determine the destination of a request it becomes trivial for
2769 malicious scripts on remote websites to bypass browser same-origin
2770 security policy and sandboxing protections.
2772 The cause of this is that such applets are allowed to perform their
2773 own HTTP stack, in which case the same-origin policy of the browser
2774 sandbox only verifies that the applet tries to contact the same IP
2775 as from where it was loaded at the IP level. The Host: header may
2776 be different from the connected IP and approved origin.
2780 NAME: client_dst_passthru
2783 LOC: Config.onoff.client_dst_passthru
2785 With NAT or TPROXY intercepted traffic Squid may pass the request
2786 directly to the original client destination IP or seek a faster
2787 source using the HTTP Host header.
2789 Using Host to locate alternative servers can provide faster
2790 connectivity with a range of failure recovery options.
2791 But can also lead to connectivity trouble when the client and
2792 server are attempting stateful interactions unaware of the proxy.
2794 This option (on by default) prevents alternative DNS entries being
2795 located to send intercepted traffic DIRECT to an origin server.
2796 The clients original destination IP and port will be used instead.
2798 Regardless of this option setting, when dealing with intercepted
2799 traffic Squid will verify the Host: header and any traffic which
2800 fails Host verification will be treated as if this option were ON.
2802 see host_verify_strict for details on the verification process.
2807 -----------------------------------------------------------------------------
2810 NAME: tls_outgoing_options
2811 IFDEF: USE_GNUTLS||USE_OPENSSL
2812 TYPE: securePeerOptions
2813 DEFAULT: min-version=1.0
2814 LOC: Security::ProxyOutgoingConfig
2816 disable Do not support https:// URLs.
2818 cert=/path/to/client/certificate
2819 A client X.509 certificate to use when connecting.
2821 key=/path/to/client/private_key
2822 The private key corresponding to the cert= above.
2824 If key= is not specified cert= is assumed to
2825 reference a PEM file containing both the certificate
2828 cipher=... The list of valid TLS ciphers to use.
2831 The minimum TLS protocol version to permit.
2832 To control SSLv3 use the options= parameter.
2833 Supported Values: 1.0 (default), 1.1, 1.2
2835 options=... Specify various TLS/SSL implementation options.
2837 OpenSSL options most important are:
2839 NO_SSLv3 Disallow the use of SSLv3
2842 Always create a new key when using
2843 temporary/ephemeral DH key exchanges
2846 Disable use of RFC5077 session tickets.
2847 Some servers may have problems
2848 understanding the TLS extension due
2849 to ambiguous specification in RFC4507.
2851 ALL Enable various bug workarounds
2852 suggested as "harmless" by OpenSSL
2853 Be warned that this reduces SSL/TLS
2854 strength to some attacks.
2856 See the OpenSSL SSL_CTX_set_options documentation
2857 for a more complete list.
2859 GnuTLS options most important are:
2862 Disable use of RFC5077 session tickets.
2863 Some servers may have problems
2864 understanding the TLS extension due
2865 to ambiguous specification in RFC4507.
2867 See the GnuTLS Priority Strings documentation
2868 for a more complete list.
2869 http://www.gnutls.org/manual/gnutls.html#Priority-Strings
2872 cafile= PEM file containing CA certificates to use when verifying
2873 the peer certificate. May be repeated to load multiple files.
2875 capath= A directory containing additional CA certificates to
2876 use when verifying the peer certificate.
2877 Requires OpenSSL or LibreSSL.
2879 crlfile=... A certificate revocation list file to use when
2880 verifying the peer certificate.
2882 flags=... Specify various flags modifying the TLS implementation:
2885 Accept certificates even if they fail to
2888 Don't verify the peer certificate
2889 matches the server name
2892 Whether to use the system Trusted CAs. Default is ON.
2894 domain= The peer name as advertised in its certificate.
2895 Used for verifying the correctness of the received peer
2896 certificate. If not specified the peer hostname will be
2902 -----------------------------------------------------------------------------
2905 NAME: ssl_unclean_shutdown
2909 LOC: Config.SSL.unclean_shutdown
2911 Some browsers (especially MSIE) bugs out on SSL shutdown
2918 LOC: Config.SSL.ssl_engine
2921 The OpenSSL engine to use. You will need to set this if you
2922 would like to use hardware SSL acceleration for example.
2925 NAME: sslproxy_session_ttl
2928 LOC: Config.SSL.session_ttl
2931 Sets the timeout value for SSL sessions
2934 NAME: sslproxy_session_cache_size
2937 LOC: Config.SSL.sessionCacheSize
2940 Sets the cache size to use for ssl session
2943 NAME: sslproxy_foreign_intermediate_certs
2946 LOC: Config.ssl_client.foreignIntermediateCertsPath
2949 Many origin servers fail to send their full server certificate
2950 chain for verification, assuming the client already has or can
2951 easily locate any missing intermediate certificates.
2953 Squid uses the certificates from the specified file to fill in
2954 these missing chains when trying to validate origin server
2957 The file is expected to contain zero or more PEM-encoded
2958 intermediate certificates. These certificates are not treated
2959 as trusted root certificates, and any self-signed certificate in
2960 this file will be ignored.
2963 NAME: sslproxy_cert_sign_hash
2966 LOC: Config.SSL.certSignHash
2969 Sets the hashing algorithm to use when signing generated certificates.
2970 Valid algorithm names depend on the OpenSSL library used. The following
2971 names are usually available: sha1, sha256, sha512, and md5. Please see
2972 your OpenSSL library manual for the available hashes. By default, Squids
2973 that support this option use sha256 hashes.
2975 Squid does not forcefully purge cached certificates that were generated
2976 with an algorithm other than the currently configured one. They remain
2977 in the cache, subject to the regular cache eviction policy, and become
2978 useful if the algorithm changes again.
2983 TYPE: sslproxy_ssl_bump
2984 LOC: Config.accessList.ssl_bump
2985 DEFAULT_DOC: Become a TCP tunnel without decrypting proxied traffic.
2988 This option is consulted when a CONNECT request is received on
2989 an http_port (or a new connection is intercepted at an
2990 https_port), provided that port was configured with an ssl-bump
2991 flag. The subsequent data on the connection is either treated as
2992 HTTPS and decrypted OR tunneled at TCP level without decryption,
2993 depending on the first matching bumping "action".
2995 ssl_bump <action> [!]acl ...
2997 The following bumping actions are currently supported:
3000 Become a TCP tunnel without decrypting proxied traffic.
3001 This is the default action.
3004 When used on step SslBump1, establishes a secure connection
3005 with the client first, then connect to the server.
3006 When used on step SslBump2 or SslBump3, establishes a secure
3007 connection with the server and, using a mimicked server
3008 certificate, with the client.
3011 Receive client (step SslBump1) or server (step SslBump2)
3012 certificate while preserving the possibility of splicing the
3013 connection. Peeking at the server certificate (during step 2)
3014 usually precludes bumping of the connection at step 3.
3017 Receive client (step SslBump1) or server (step SslBump2)
3018 certificate while preserving the possibility of bumping the
3019 connection. Staring at the server certificate (during step 2)
3020 usually precludes splicing of the connection at step 3.
3023 Close client and server connections.
3025 Backward compatibility actions available at step SslBump1:
3028 Bump the connection. Establish a secure connection with the
3029 client first, then connect to the server. This old mode does
3030 not allow Squid to mimic server SSL certificate and does not
3031 work with intercepted SSL connections.
3034 Bump the connection. Establish a secure connection with the
3035 server first, then establish a secure connection with the
3036 client, using a mimicked server certificate. Works with both
3037 CONNECT requests and intercepted SSL connections, but does
3038 not allow to make decisions based on SSL handshake info.
3041 Decide whether to bump or splice the connection based on
3042 client-to-squid and server-to-squid SSL hello messages.
3046 Same as the "splice" action.
3048 All ssl_bump rules are evaluated at each of the supported bumping
3049 steps. Rules with actions that are impossible at the current step are
3050 ignored. The first matching ssl_bump action wins and is applied at the
3051 end of the current step. If no rules match, the splice action is used.
3052 See the at_step ACL for a list of the supported SslBump steps.
3054 This clause supports both fast and slow acl types.
3055 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
3057 See also: http_port ssl-bump, https_port ssl-bump, and acl at_step.
3060 # Example: Bump all TLS connections except those originating from
3061 # localhost or those going to example.com.
3063 acl broken_sites ssl::server_name .example.com
3064 ssl_bump splice localhost
3065 ssl_bump splice broken_sites
3069 NAME: sslproxy_cert_error
3072 DEFAULT_DOC: Server certificate errors terminate the transaction.
3073 LOC: Config.ssl_client.cert_error
3076 Use this ACL to bypass server certificate validation errors.
3078 For example, the following lines will bypass all validation errors
3079 when talking to servers for example.com. All other
3080 validation errors will result in ERR_SECURE_CONNECT_FAIL error.
3082 acl BrokenButTrustedServers dstdomain example.com
3083 sslproxy_cert_error allow BrokenButTrustedServers
3084 sslproxy_cert_error deny all
3086 This clause only supports fast acl types.
3087 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
3088 Using slow acl types may result in server crashes
3090 Without this option, all server certificate validation errors
3091 terminate the transaction to protect Squid and the client.
3093 SQUID_X509_V_ERR_INFINITE_VALIDATION error cannot be bypassed
3094 but should not happen unless your OpenSSL library is buggy.
3097 Bypassing validation errors is dangerous because an
3098 error usually implies that the server cannot be trusted
3099 and the connection may be insecure.
3101 See also: sslproxy_flags and DONT_VERIFY_PEER.
3104 NAME: sslproxy_cert_sign
3107 POSTSCRIPTUM: signUntrusted ssl::certUntrusted
3108 POSTSCRIPTUM: signSelf ssl::certSelfSigned
3109 POSTSCRIPTUM: signTrusted all
3110 TYPE: sslproxy_cert_sign
3111 LOC: Config.ssl_client.cert_sign
3114 sslproxy_cert_sign <signing algorithm> acl ...
3116 The following certificate signing algorithms are supported:
3119 Sign using the configured CA certificate which is usually
3120 placed in and trusted by end-user browsers. This is the
3121 default for trusted origin server certificates.
3124 Sign to guarantee an X509_V_ERR_CERT_UNTRUSTED browser error.
3125 This is the default for untrusted origin server certificates
3126 that are not self-signed (see ssl::certUntrusted).
3129 Sign using a self-signed certificate with the right CN to
3130 generate a X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT error in the
3131 browser. This is the default for self-signed origin server
3132 certificates (see ssl::certSelfSigned).
3134 This clause only supports fast acl types.
3136 When sslproxy_cert_sign acl(s) match, Squid uses the corresponding
3137 signing algorithm to generate the certificate and ignores all
3138 subsequent sslproxy_cert_sign options (the first match wins). If no
3139 acl(s) match, the default signing algorithm is determined by errors
3140 detected when obtaining and validating the origin server certificate.
3142 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
3143 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
3144 CONNECT request that carries a domain name. In all other cases (CONNECT
3145 to an IP address or an intercepted SSL connection), Squid cannot detect
3146 the domain mismatch at certificate generation time when
3147 bump-server-first is used.
3150 NAME: sslproxy_cert_adapt
3153 TYPE: sslproxy_cert_adapt
3154 LOC: Config.ssl_client.cert_adapt
3157 sslproxy_cert_adapt <adaptation algorithm> acl ...
3159 The following certificate adaptation algorithms are supported:
3162 Sets the "Not After" property to the "Not After" property of
3163 the CA certificate used to sign generated certificates.
3166 Sets the "Not Before" property to the "Not Before" property of
3167 the CA certificate used to sign generated certificates.
3169 setCommonName or setCommonName{CN}
3170 Sets Subject.CN property to the host name specified as a
3171 CN parameter or, if no explicit CN parameter was specified,
3172 extracted from the CONNECT request. It is a misconfiguration
3173 to use setCommonName without an explicit parameter for
3174 intercepted or tproxied SSL connections.
3176 This clause only supports fast acl types.
3178 Squid first groups sslproxy_cert_adapt options by adaptation algorithm.
3179 Within a group, when sslproxy_cert_adapt acl(s) match, Squid uses the
3180 corresponding adaptation algorithm to generate the certificate and
3181 ignores all subsequent sslproxy_cert_adapt options in that algorithm's
3182 group (i.e., the first match wins within each algorithm group). If no
3183 acl(s) match, the default mimicking action takes place.
3185 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
3186 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
3187 CONNECT request that carries a domain name. In all other cases (CONNECT
3188 to an IP address or an intercepted SSL connection), Squid cannot detect
3189 the domain mismatch at certificate generation time when
3190 bump-server-first is used.
3193 NAME: sslpassword_program
3196 LOC: Config.Program.ssl_password
3199 Specify a program used for entering SSL key passphrases
3200 when using encrypted SSL certificate keys. If not specified
3201 keys must either be unencrypted, or Squid started with the -N
3202 option to allow it to query interactively for the passphrase.
3204 The key file name is given as argument to the program allowing
3205 selection of the right password if you have multiple encrypted
3210 OPTIONS RELATING TO EXTERNAL SSL_CRTD
3211 -----------------------------------------------------------------------------
3214 NAME: sslcrtd_program
3217 DEFAULT: @DEFAULT_SSL_CRTD@ -s @DEFAULT_SSL_DB_DIR@ -M 4MB
3218 LOC: Ssl::TheConfig.ssl_crtd
3220 Specify the location and options of the executable for certificate
3222 @DEFAULT_SSL_CRTD@ program requires -s and -M parameters
3223 For more information use:
3224 @DEFAULT_SSL_CRTD@ -h
3227 NAME: sslcrtd_children
3228 TYPE: HelperChildConfig
3230 DEFAULT: 32 startup=5 idle=1
3231 LOC: Ssl::TheConfig.ssl_crtdChildren
3233 The maximum number of processes spawn to service ssl server.
3234 The maximum this may be safely set to is 32.
3236 The startup= and idle= options allow some measure of skew in your
3241 Sets the minimum number of processes to spawn when Squid
3242 starts or reconfigures. When set to zero the first request will
3243 cause spawning of the first child process to handle it.
3245 Starting too few children temporary slows Squid under load while it
3246 tries to spawn enough additional processes to cope with traffic.
3250 Sets a minimum of how many processes Squid is to try and keep available
3251 at all times. When traffic begins to rise above what the existing
3252 processes can handle this many more will be spawned up to the maximum
3253 configured. A minimum setting of 1 is required.
3257 Sets the maximum number of queued requests.
3258 If the queued requests exceed queue size for more than 3 minutes
3259 squid aborts its operation.
3260 The default value is set to 2*numberofchildren.
3262 You must have at least one ssl_crtd process.
3265 NAME: sslcrtvalidator_program
3269 LOC: Ssl::TheConfig.ssl_crt_validator
3271 Specify the location and options of the executable for ssl_crt_validator
3274 Usage: sslcrtvalidator_program [ttl=n] [cache=n] path ...
3277 ttl=n TTL in seconds for cached results. The default is 60 secs
3278 cache=n limit the result cache size. The default value is 2048
3281 NAME: sslcrtvalidator_children
3282 TYPE: HelperChildConfig
3284 DEFAULT: 32 startup=5 idle=1 concurrency=1
3285 LOC: Ssl::TheConfig.ssl_crt_validator_Children
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 The number of requests each certificate validator helper can handle in
3312 parallel. A value of 0 indicates the certficate validator does not
3313 support concurrency. Defaults to 1.
3315 When this directive is set to a value >= 1 then the protocol
3316 used to communicate with the helper is modified to include
3317 a request ID in front of the request/response. The request
3318 ID from the request must be echoed back with the response
3323 Sets the maximum number of queued requests.
3324 If the queued requests exceed queue size for more than 3 minutes
3325 squid aborts its operation.
3326 The default value is set to 2*numberofchildren.
3328 You must have at least one ssl_crt_validator process.
3332 OPTIONS WHICH AFFECT THE NEIGHBOR SELECTION ALGORITHM
3333 -----------------------------------------------------------------------------
3341 To specify other caches in a hierarchy, use the format:
3343 cache_peer hostname type http-port icp-port [options]
3348 # hostname type port port options
3349 # -------------------- -------- ----- ----- -----------
3350 cache_peer parent.foo.net parent 3128 3130 default
3351 cache_peer sib1.foo.net sibling 3128 3130 proxy-only
3352 cache_peer sib2.foo.net sibling 3128 3130 proxy-only
3353 cache_peer example.com parent 80 0 default
3354 cache_peer cdn.example.com sibling 3128 0
3356 type: either 'parent', 'sibling', or 'multicast'.
3358 proxy-port: The port number where the peer accept HTTP requests.
3359 For other Squid proxies this is usually 3128
3360 For web servers this is usually 80
3362 icp-port: Used for querying neighbor caches about objects.
3363 Set to 0 if the peer does not support ICP or HTCP.
3364 See ICP and HTCP options below for additional details.
3367 ==== ICP OPTIONS ====
3369 You MUST also set icp_port and icp_access explicitly when using these options.
3370 The defaults will prevent peer traffic using ICP.
3373 no-query Disable ICP queries to this neighbor.
3376 Indicates the named peer is a member of a multicast group.
3377 ICP queries will not be sent directly to the peer, but ICP
3378 replies will be accepted from it.
3380 closest-only Indicates that, for ICP_OP_MISS replies, we'll only forward
3381 CLOSEST_PARENT_MISSes and never FIRST_PARENT_MISSes.
3384 To only send ICP queries to this neighbor infrequently.
3385 This is used to keep the neighbor round trip time updated
3386 and is usually used in conjunction with weighted-round-robin.
3389 ==== HTCP OPTIONS ====
3391 You MUST also set htcp_port and htcp_access explicitly when using these options.
3392 The defaults will prevent peer traffic using HTCP.
3395 htcp Send HTCP, instead of ICP, queries to the neighbor.
3396 You probably also want to set the "icp-port" to 4827
3397 instead of 3130. This directive accepts a comma separated
3398 list of options described below.
3400 htcp=oldsquid Send HTCP to old Squid versions (2.5 or earlier).
3402 htcp=no-clr Send HTCP to the neighbor but without
3403 sending any CLR requests. This cannot be used with
3406 htcp=only-clr Send HTCP to the neighbor but ONLY CLR requests.
3407 This cannot be used with no-clr.
3410 Send HTCP to the neighbor including CLRs but only when
3411 they do not result from PURGE requests.
3414 Forward any HTCP CLR requests this proxy receives to the peer.
3417 ==== PEER SELECTION METHODS ====
3419 The default peer selection method is ICP, with the first responding peer
3420 being used as source. These options can be used for better load balancing.
3423 default This is a parent cache which can be used as a "last-resort"
3424 if a peer cannot be located by any of the peer-selection methods.
3425 If specified more than once, only the first is used.
3427 round-robin Load-Balance parents which should be used in a round-robin
3428 fashion in the absence of any ICP queries.
3429 weight=N can be used to add bias.
3431 weighted-round-robin
3432 Load-Balance parents which should be used in a round-robin
3433 fashion with the frequency of each parent being based on the
3434 round trip time. Closer parents are used more often.
3435 Usually used for background-ping parents.
3436 weight=N can be used to add bias.
3438 carp Load-Balance parents which should be used as a CARP array.
3439 The requests will be distributed among the parents based on the
3440 CARP load balancing hash function based on their weight.
3442 userhash Load-balance parents based on the client proxy_auth or ident username.
3444 sourcehash Load-balance parents based on the client source IP.
3447 To be used only for cache peers of type "multicast".
3448 ALL members of this multicast group have "sibling"
3449 relationship with it, not "parent". This is to a multicast
3450 group when the requested object would be fetched only from
3451 a "parent" cache, anyway. It's useful, e.g., when
3452 configuring a pool of redundant Squid proxies, being
3453 members of the same multicast group.
3456 ==== PEER SELECTION OPTIONS ====
3458 weight=N use to affect the selection of a peer during any weighted
3459 peer-selection mechanisms.
3460 The weight must be an integer; default is 1,
3461 larger weights are favored more.
3462 This option does not affect parent selection if a peering
3463 protocol is not in use.
3465 basetime=N Specify a base amount to be subtracted from round trip
3467 It is subtracted before division by weight in calculating
3468 which parent to fectch from. If the rtt is less than the
3469 base time the rtt is set to a minimal value.
3471 ttl=N Specify a TTL to use when sending multicast ICP queries
3473 Only useful when sending to a multicast group.
3474 Because we don't accept ICP replies from random
3475 hosts, you must configure other group members as
3476 peers with the 'multicast-responder' option.
3478 no-delay To prevent access to this neighbor from influencing the
3481 digest-url=URL Tell Squid to fetch the cache digest (if digests are
3482 enabled) for this host from the specified URL rather
3483 than the Squid default location.
3486 ==== CARP OPTIONS ====
3488 carp-key=key-specification
3489 use a different key than the full URL to hash against the peer.
3490 the key-specification is a comma-separated list of the keywords
3491 scheme, host, port, path, params
3492 Order is not important.
3494 ==== ACCELERATOR / REVERSE-PROXY OPTIONS ====
3496 originserver Causes this parent to be contacted as an origin server.
3497 Meant to be used in accelerator setups when the peer
3501 Set the Host header of requests forwarded to this peer.
3502 Useful in accelerator setups where the server (peer)
3503 expects a certain domain name but clients may request
3504 others. ie example.com or www.example.com
3506 no-digest Disable request of cache digests.
3509 Disables requesting ICMP RTT database (NetDB).
3512 ==== AUTHENTICATION OPTIONS ====
3515 If this is a personal/workgroup proxy and your parent
3516 requires proxy authentication.
3518 Note: The string can include URL escapes (i.e. %20 for
3519 spaces). This also means % must be written as %%.
3522 Send login details received from client to this peer.
3523 Both Proxy- and WWW-Authorization headers are passed
3524 without alteration to the peer.
3525 Authentication is not required by Squid for this to work.
3527 Note: This will pass any form of authentication but
3528 only Basic auth will work through a proxy unless the
3529 connection-auth options are also used.
3531 login=PASS Send login details received from client to this peer.
3532 Authentication is not required by this option.
3534 If there are no client-provided authentication headers
3535 to pass on, but username and password are available
3536 from an external ACL user= and password= result tags
3537 they may be sent instead.
3539 Note: To combine this with proxy_auth both proxies must
3540 share the same user database as HTTP only allows for
3541 a single login (one for proxy, one for origin server).
3542 Also be warned this will expose your users proxy
3543 password to the peer. USE WITH CAUTION
3546 Send the username to the upstream cache, but with a
3547 fixed password. This is meant to be used when the peer
3548 is in another administrative domain, but it is still
3549 needed to identify each user.
3550 The star can optionally be followed by some extra
3551 information which is added to the username. This can
3552 be used to identify this proxy to the peer, similar to
3553 the login=username:password option above.
3556 If this is a personal/workgroup proxy and your parent
3557 requires a secure proxy authentication.
3558 The first principal from the default keytab or defined by
3559 the environment variable KRB5_KTNAME will be used.
3561 WARNING: The connection may transmit requests from multiple
3562 clients. Negotiate often assumes end-to-end authentication
3563 and a single-client. Which is not strictly true here.
3565 login=NEGOTIATE:principal_name
3566 If this is a personal/workgroup proxy and your parent
3567 requires a secure proxy authentication.
3568 The principal principal_name from the default keytab or
3569 defined by the environment variable KRB5_KTNAME will be
3572 WARNING: The connection may transmit requests from multiple
3573 clients. Negotiate often assumes end-to-end authentication
3574 and a single-client. Which is not strictly true here.
3576 connection-auth=on|off
3577 Tell Squid that this peer does or not support Microsoft
3578 connection oriented authentication, and any such
3579 challenges received from there should be ignored.
3580 Default is auto to automatically determine the status
3584 Do not use a keytab to authenticate to a peer when
3585 login=NEGOTIATE is specified. Let the GSSAPI
3586 implementation determine which already existing
3587 credentials cache to use instead.
3590 ==== SSL / HTTPS / TLS OPTIONS ====
3592 tls Encrypt connections to this peer with TLS.
3594 sslcert=/path/to/ssl/certificate
3595 A client X.509 certificate to use when connecting to
3598 sslkey=/path/to/ssl/key
3599 The private key corresponding to sslcert above.
3601 If sslkey= is not specified sslcert= is assumed to
3602 reference a PEM file containing both the certificate
3605 sslcipher=... The list of valid SSL ciphers to use when connecting
3609 The minimum TLS protocol version to permit. To control
3610 SSLv3 use the tls-options= parameter.
3611 Supported Values: 1.0 (default), 1.1, 1.2
3613 tls-options=... Specify various TLS implementation options.
3615 OpenSSL options most important are:
3617 NO_SSLv3 Disallow the use of SSLv3
3620 Always create a new key when using
3621 temporary/ephemeral DH key exchanges
3624 Disable use of RFC5077 session tickets.
3625 Some servers may have problems
3626 understanding the TLS extension due
3627 to ambiguous specification in RFC4507.
3629 ALL Enable various bug workarounds
3630 suggested as "harmless" by OpenSSL
3631 Be warned that this reduces SSL/TLS
3632 strength to some attacks.
3634 See the OpenSSL SSL_CTX_set_options documentation for a
3637 GnuTLS options most important are:
3640 Disable use of RFC5077 session tickets.
3641 Some servers may have problems
3642 understanding the TLS extension due
3643 to ambiguous specification in RFC4507.
3645 See the GnuTLS Priority Strings documentation
3646 for a more complete list.
3647 http://www.gnutls.org/manual/gnutls.html#Priority-Strings
3649 tls-cafile= PEM file containing CA certificates to use when verifying
3650 the peer certificate. May be repeated to load multiple files.
3652 sslcapath=... A directory containing additional CA certificates to
3653 use when verifying the peer certificate.
3654 Requires OpenSSL or LibreSSL.
3656 sslcrlfile=... A certificate revocation list file to use when
3657 verifying the peer certificate.
3659 sslflags=... Specify various flags modifying the SSL implementation:
3662 Accept certificates even if they fail to
3666 Don't verify the peer certificate
3667 matches the server name
3669 ssldomain= The peer name as advertised in it's certificate.
3670 Used for verifying the correctness of the received peer
3671 certificate. If not specified the peer hostname will be
3674 front-end-https[=off|on|auto]
3675 Enable the "Front-End-Https: On" header needed when
3676 using Squid as a SSL frontend in front of Microsoft OWA.
3677 See MS KB document Q307347 for details on this header.
3678 If set to auto the header will only be added if the
3679 request is forwarded as a https:// URL.
3681 tls-default-ca[=off]
3682 Whether to use the system Trusted CAs. Default is ON.
3684 tls-no-npn Do not use the TLS NPN extension to advertise HTTP/1.1.
3686 ==== GENERAL OPTIONS ====
3689 A peer-specific connect timeout.
3690 Also see the peer_connect_timeout directive.
3692 connect-fail-limit=N
3693 How many times connecting to a peer must fail before
3694 it is marked as down. Standby connection failures
3695 count towards this limit. Default is 10.
3697 allow-miss Disable Squid's use of only-if-cached when forwarding
3698 requests to siblings. This is primarily useful when
3699 icp_hit_stale is used by the sibling. Excessive use
3700 of this option may result in forwarding loops. One way
3701 to prevent peering loops when using this option, is to
3702 deny cache peer usage on requests from a peer:
3704 cache_peer_access peerName deny fromPeer
3706 max-conn=N Limit the number of concurrent connections the Squid
3707 may open to this peer, including already opened idle
3708 and standby connections. There is no peer-specific
3709 connection limit by default.
3711 A peer exceeding the limit is not used for new
3712 requests unless a standby connection is available.
3714 max-conn currently works poorly with idle persistent
3715 connections: When a peer reaches its max-conn limit,
3716 and there are idle persistent connections to the peer,
3717 the peer may not be selected because the limiting code
3718 does not know whether Squid can reuse those idle
3721 standby=N Maintain a pool of N "hot standby" connections to an
3722 UP peer, available for requests when no idle
3723 persistent connection is available (or safe) to use.
3724 By default and with zero N, no such pool is maintained.
3725 N must not exceed the max-conn limit (if any).
3727 At start or after reconfiguration, Squid opens new TCP
3728 standby connections until there are N connections
3729 available and then replenishes the standby pool as
3730 opened connections are used up for requests. A used
3731 connection never goes back to the standby pool, but
3732 may go to the regular idle persistent connection pool
3733 shared by all peers and origin servers.
3735 Squid never opens multiple new standby connections
3736 concurrently. This one-at-a-time approach minimizes
3737 flooding-like effect on peers. Furthermore, just a few
3738 standby connections should be sufficient in most cases
3739 to supply most new requests with a ready-to-use
3742 Standby connections obey server_idle_pconn_timeout.
3743 For the feature to work as intended, the peer must be
3744 configured to accept and keep them open longer than
3745 the idle timeout at the connecting Squid, to minimize
3746 race conditions typical to idle used persistent
3747 connections. Default request_timeout and
3748 server_idle_pconn_timeout values ensure such a
3751 name=xxx Unique name for the peer.
3752 Required if you have multiple peers on the same host
3753 but different ports.
3754 This name can be used in cache_peer_access and similar
3755 directives to identify the peer.
3756 Can be used by outgoing access controls through the
3759 no-tproxy Do not use the client-spoof TPROXY support when forwarding
3760 requests to this peer. Use normal address selection instead.
3761 This overrides the spoof_client_ip ACL.
3763 proxy-only objects fetched from the peer will not be stored locally.
3767 NAME: cache_peer_access
3770 DEFAULT_DOC: No peer usage restrictions.
3773 Restricts usage of cache_peer proxies.
3776 cache_peer_access peer-name allow|deny [!]aclname ...
3778 For the required peer-name parameter, use either the value of the
3779 cache_peer name=value parameter or, if name=value is missing, the
3780 cache_peer hostname parameter.
3782 This directive narrows down the selection of peering candidates, but
3783 does not determine the order in which the selected candidates are
3784 contacted. That order is determined by the peer selection algorithms
3785 (see PEER SELECTION sections in the cache_peer documentation).
3787 If a deny rule matches, the corresponding peer will not be contacted
3788 for the current transaction -- Squid will not send ICP queries and
3789 will not forward HTTP requests to that peer. An allow match leaves
3790 the corresponding peer in the selection. The first match for a given
3791 peer wins for that peer.
3793 The relative order of cache_peer_access directives for the same peer
3794 matters. The relative order of any two cache_peer_access directives
3795 for different peers does not matter. To ease interpretation, it is a
3796 good idea to group cache_peer_access directives for the same peer
3799 A single cache_peer_access directive may be evaluated multiple times
3800 for a given transaction because individual peer selection algorithms
3801 may check it independently from each other. These redundant checks
3802 may be optimized away in future Squid versions.
3804 This clause only supports fast acl types.
3805 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
3809 NAME: neighbor_type_domain
3810 TYPE: hostdomaintype
3812 DEFAULT_DOC: The peer type from cache_peer directive is used for all requests to that peer.
3815 Modify the cache_peer neighbor type when passing requests
3816 about specific domains to the peer.
3819 neighbor_type_domain neighbor parent|sibling domain domain ...
3822 cache_peer foo.example.com parent 3128 3130
3823 neighbor_type_domain foo.example.com sibling .au .de
3825 The above configuration treats all requests to foo.example.com as a
3826 parent proxy unless the request is for a .au or .de ccTLD domain name.
3829 NAME: dead_peer_timeout
3833 LOC: Config.Timeout.deadPeer
3835 This controls how long Squid waits to declare a peer cache
3836 as "dead." If there are no ICP replies received in this
3837 amount of time, Squid will declare the peer dead and not
3838 expect to receive any further ICP replies. However, it
3839 continues to send ICP queries, and will mark the peer as
3840 alive upon receipt of the first subsequent ICP reply.
3842 This timeout also affects when Squid expects to receive ICP
3843 replies from peers. If more than 'dead_peer' seconds have
3844 passed since the last ICP reply was received, Squid will not
3845 expect to receive an ICP reply on the next query. Thus, if
3846 your time between requests is greater than this timeout, you
3847 will see a lot of requests sent DIRECT to origin servers
3848 instead of to your parents.
3851 NAME: forward_max_tries
3854 LOC: Config.forward_max_tries
3856 Controls how many different forward paths Squid will try
3857 before giving up. See also forward_timeout.
3859 NOTE: connect_retries (default: none) can make each of these
3860 possible forwarding paths be tried multiple times.
3864 MEMORY CACHE OPTIONS
3865 -----------------------------------------------------------------------------
3872 LOC: Config.memMaxSize
3874 NOTE: THIS PARAMETER DOES NOT SPECIFY THE MAXIMUM PROCESS SIZE.
3875 IT ONLY PLACES A LIMIT ON HOW MUCH ADDITIONAL MEMORY SQUID WILL
3876 USE AS A MEMORY CACHE OF OBJECTS. SQUID USES MEMORY FOR OTHER
3877 THINGS AS WELL. SEE THE SQUID FAQ SECTION 8 FOR DETAILS.
3879 'cache_mem' specifies the ideal amount of memory to be used
3881 * In-Transit objects
3883 * Negative-Cached objects
3885 Data for these objects are stored in 4 KB blocks. This
3886 parameter specifies the ideal upper limit on the total size of
3887 4 KB blocks allocated. In-Transit objects take the highest
3890 In-transit objects have priority over the others. When
3891 additional space is needed for incoming data, negative-cached
3892 and hot objects will be released. In other words, the
3893 negative-cached and hot objects will fill up any unused space
3894 not needed for in-transit objects.
3896 If circumstances require, this limit will be exceeded.
3897 Specifically, if your incoming request rate requires more than
3898 'cache_mem' of memory to hold in-transit objects, Squid will
3899 exceed this limit to satisfy the new requests. When the load
3900 decreases, blocks will be freed until the high-water mark is
3901 reached. Thereafter, blocks will be used to store hot
3904 If shared memory caching is enabled, Squid does not use the shared
3905 cache space for in-transit objects, but they still consume as much
3906 local memory as they need. For more details about the shared memory
3907 cache, see memory_cache_shared.
3910 NAME: maximum_object_size_in_memory
3914 LOC: Config.Store.maxInMemObjSize
3916 Objects greater than this size will not be attempted to kept in
3917 the memory cache. This should be set high enough to keep objects
3918 accessed frequently in memory to improve performance whilst low
3919 enough to keep larger objects from hoarding cache_mem.
3922 NAME: memory_cache_shared
3925 LOC: Config.memShared
3927 DEFAULT_DOC: "on" where supported if doing memory caching with multiple SMP workers.
3929 Controls whether the memory cache is shared among SMP workers.
3931 The shared memory cache is meant to occupy cache_mem bytes and replace
3932 the non-shared memory cache, although some entities may still be
3933 cached locally by workers for now (e.g., internal and in-transit
3934 objects may be served from a local memory cache even if shared memory
3935 caching is enabled).
3937 By default, the memory cache is shared if and only if all of the
3938 following conditions are satisfied: Squid runs in SMP mode with
3939 multiple workers, cache_mem is positive, and Squid environment
3940 supports required IPC primitives (e.g., POSIX shared memory segments
3941 and GCC-style atomic operations).
3943 To avoid blocking locks, shared memory uses opportunistic algorithms
3944 that do not guarantee that every cachable entity that could have been
3945 shared among SMP workers will actually be shared.
3948 NAME: memory_cache_mode
3952 DEFAULT_DOC: Keep the most recently fetched objects in memory
3954 Controls which objects to keep in the memory cache (cache_mem)
3956 always Keep most recently fetched objects in memory (default)
3958 disk Only disk cache hits are kept in memory, which means
3959 an object must first be cached on disk and then hit
3960 a second time before cached in memory.
3962 network Only objects fetched from network is kept in memory
3965 NAME: memory_replacement_policy
3967 LOC: Config.memPolicy
3970 The memory replacement policy parameter determines which
3971 objects are purged from memory when memory space is needed.
3973 See cache_replacement_policy for details on algorithms.
3978 -----------------------------------------------------------------------------
3981 NAME: cache_replacement_policy
3983 LOC: Config.replPolicy
3986 The cache replacement policy parameter determines which
3987 objects are evicted (replaced) when disk space is needed.
3989 lru : Squid's original list based LRU policy
3990 heap GDSF : Greedy-Dual Size Frequency
3991 heap LFUDA: Least Frequently Used with Dynamic Aging
3992 heap LRU : LRU policy implemented using a heap
3994 Applies to any cache_dir lines listed below this directive.
3996 The LRU policies keeps recently referenced objects.
3998 The heap GDSF policy optimizes object hit rate by keeping smaller
3999 popular objects in cache so it has a better chance of getting a
4000 hit. It achieves a lower byte hit rate than LFUDA though since
4001 it evicts larger (possibly popular) objects.
4003 The heap LFUDA policy keeps popular objects in cache regardless of
4004 their size and thus optimizes byte hit rate at the expense of
4005 hit rate since one large, popular object will prevent many
4006 smaller, slightly less popular objects from being cached.
4008 Both policies utilize a dynamic aging mechanism that prevents
4009 cache pollution that can otherwise occur with frequency-based
4010 replacement policies.
4012 NOTE: if using the LFUDA replacement policy you should increase
4013 the value of maximum_object_size above its default of 4 MB to
4014 to maximize the potential byte hit rate improvement of LFUDA.
4016 For more information about the GDSF and LFUDA cache replacement
4017 policies see http://www.hpl.hp.com/techreports/1999/HPL-1999-69.html
4018 and http://fog.hpl.external.hp.com/techreports/98/HPL-98-173.html.
4021 NAME: minimum_object_size
4025 DEFAULT_DOC: no limit
4026 LOC: Config.Store.minObjectSize
4028 Objects smaller than this size will NOT be saved on disk. The
4029 value is specified in bytes, and the default is 0 KB, which
4030 means all responses can be stored.
4033 NAME: maximum_object_size
4037 LOC: Config.Store.maxObjectSize
4039 Set the default value for max-size parameter on any cache_dir.
4040 The value is specified in bytes, and the default is 4 MB.
4042 If you wish to get a high BYTES hit ratio, you should probably
4043 increase this (one 32 MB object hit counts for 3200 10KB
4046 If you wish to increase hit ratio more than you want to
4047 save bandwidth you should leave this low.
4049 NOTE: if using the LFUDA replacement policy you should increase
4050 this value to maximize the byte hit rate improvement of LFUDA!
4051 See cache_replacement_policy for a discussion of this policy.
4057 DEFAULT_DOC: No disk cache. Store cache ojects only in memory.
4058 LOC: Config.cacheSwap
4061 cache_dir Type Directory-Name Fs-specific-data [options]
4063 You can specify multiple cache_dir lines to spread the
4064 cache among different disk partitions.
4066 Type specifies the kind of storage system to use. Only "ufs"
4067 is built by default. To enable any of the other storage systems
4068 see the --enable-storeio configure option.
4070 'Directory' is a top-level directory where cache swap
4071 files will be stored. If you want to use an entire disk
4072 for caching, this can be the mount-point directory.
4073 The directory must exist and be writable by the Squid
4074 process. Squid will NOT create this directory for you.
4076 In SMP configurations, cache_dir must not precede the workers option
4077 and should use configuration macros or conditionals to give each
4078 worker interested in disk caching a dedicated cache directory.
4081 ==== The ufs store type ====
4083 "ufs" is the old well-known Squid storage format that has always
4087 cache_dir ufs Directory-Name Mbytes L1 L2 [options]
4089 'Mbytes' is the amount of disk space (MB) to use under this
4090 directory. The default is 100 MB. Change this to suit your
4091 configuration. Do NOT put the size of your disk drive here.
4092 Instead, if you want Squid to use the entire disk drive,
4093 subtract 20% and use that value.
4095 'L1' is the number of first-level subdirectories which
4096 will be created under the 'Directory'. The default is 16.
4098 'L2' is the number of second-level subdirectories which
4099 will be created under each first-level directory. The default
4103 ==== The aufs store type ====
4105 "aufs" uses the same storage format as "ufs", utilizing
4106 POSIX-threads to avoid blocking the main Squid process on
4107 disk-I/O. This was formerly known in Squid as async-io.
4110 cache_dir aufs Directory-Name Mbytes L1 L2 [options]
4112 see argument descriptions under ufs above
4115 ==== The diskd store type ====
4117 "diskd" uses the same storage format as "ufs", utilizing a
4118 separate process to avoid blocking the main Squid process on
4122 cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n]
4124 see argument descriptions under ufs above
4126 Q1 specifies the number of unacknowledged I/O requests when Squid
4127 stops opening new files. If this many messages are in the queues,
4128 Squid won't open new files. Default is 64
4130 Q2 specifies the number of unacknowledged messages when Squid
4131 starts blocking. If this many messages are in the queues,
4132 Squid blocks until it receives some replies. Default is 72
4134 When Q1 < Q2 (the default), the cache directory is optimized
4135 for lower response time at the expense of a decrease in hit
4136 ratio. If Q1 > Q2, the cache directory is optimized for
4137 higher hit ratio at the expense of an increase in response
4141 ==== The rock store type ====
4144 cache_dir rock Directory-Name Mbytes [options]
4146 The Rock Store type is a database-style storage. All cached
4147 entries are stored in a "database" file, using fixed-size slots.
4148 A single entry occupies one or more slots.
4150 If possible, Squid using Rock Store creates a dedicated kid
4151 process called "disker" to avoid blocking Squid worker(s) on disk
4152 I/O. One disker kid is created for each rock cache_dir. Diskers
4153 are created only when Squid, running in daemon mode, has support
4154 for the IpcIo disk I/O module.
4156 swap-timeout=msec: Squid will not start writing a miss to or
4157 reading a hit from disk if it estimates that the swap operation
4158 will take more than the specified number of milliseconds. By
4159 default and when set to zero, disables the disk I/O time limit
4160 enforcement. Ignored when using blocking I/O module because
4161 blocking synchronous I/O does not allow Squid to estimate the
4162 expected swap wait time.
4164 max-swap-rate=swaps/sec: Artificially limits disk access using
4165 the specified I/O rate limit. Swap out requests that
4166 would cause the average I/O rate to exceed the limit are
4167 delayed. Individual swap in requests (i.e., hits or reads) are
4168 not delayed, but they do contribute to measured swap rate and
4169 since they are placed in the same FIFO queue as swap out
4170 requests, they may wait longer if max-swap-rate is smaller.
4171 This is necessary on file systems that buffer "too
4172 many" writes and then start blocking Squid and other processes
4173 while committing those writes to disk. Usually used together
4174 with swap-timeout to avoid excessive delays and queue overflows
4175 when disk demand exceeds available disk "bandwidth". By default
4176 and when set to zero, disables the disk I/O rate limit
4177 enforcement. Currently supported by IpcIo module only.
4179 slot-size=bytes: The size of a database "record" used for
4180 storing cached responses. A cached response occupies at least
4181 one slot and all database I/O is done using individual slots so
4182 increasing this parameter leads to more disk space waste while
4183 decreasing it leads to more disk I/O overheads. Should be a
4184 multiple of your operating system I/O page size. Defaults to
4185 16KBytes. A housekeeping header is stored with each slot and
4186 smaller slot-sizes will be rejected. The header is smaller than
4190 ==== COMMON OPTIONS ====
4192 no-store no new objects should be stored to this cache_dir.
4194 min-size=n the minimum object size in bytes this cache_dir
4195 will accept. It's used to restrict a cache_dir
4196 to only store large objects (e.g. AUFS) while
4197 other stores are optimized for smaller objects
4201 max-size=n the maximum object size in bytes this cache_dir
4203 The value in maximum_object_size directive sets
4204 the default unless more specific details are
4205 available (ie a small store capacity).
4207 Note: To make optimal use of the max-size limits you should order
4208 the cache_dir lines with the smallest max-size value first.
4212 # Uncomment and adjust the following to add a disk cache directory.
4213 #cache_dir ufs @DEFAULT_SWAP_DIR@ 100 16 256
4217 NAME: store_dir_select_algorithm
4219 LOC: Config.store_dir_select_algorithm
4222 How Squid selects which cache_dir to use when the response
4223 object will fit into more than one.
4225 Regardless of which algorithm is used the cache_dir min-size
4226 and max-size parameters are obeyed. As such they can affect
4227 the selection algorithm by limiting the set of considered
4234 This algorithm is suited to caches with similar cache_dir
4235 sizes and disk speeds.
4237 The disk with the least I/O pending is selected.
4238 When there are multiple disks with the same I/O load ranking
4239 the cache_dir with most available capacity is selected.
4241 When a mix of cache_dir sizes are configured the faster disks
4242 have a naturally lower I/O loading and larger disks have more
4243 capacity. So space used to store objects and data throughput
4244 may be very unbalanced towards larger disks.
4249 This algorithm is suited to caches with unequal cache_dir
4252 Each cache_dir is selected in a rotation. The next suitable
4255 Available cache_dir capacity is only considered in relation
4256 to whether the object will fit and meets the min-size and
4257 max-size parameters.
4259 Disk I/O loading is only considered to prevent overload on slow
4260 disks. This algorithm does not spread objects by size, so any
4261 I/O loading per-disk may appear very unbalanced and volatile.
4263 If several cache_dirs use similar min-size, max-size, or other
4264 limits to to reject certain responses, then do not group such
4265 cache_dir lines together, to avoid round-robin selection bias
4266 towards the first cache_dir after the group. Instead, interleave
4267 cache_dir lines from different groups. For example:
4269 store_dir_select_algorithm round-robin
4270 cache_dir rock /hdd1 ... min-size=100000
4271 cache_dir rock /ssd1 ... max-size=99999
4272 cache_dir rock /hdd2 ... min-size=100000
4273 cache_dir rock /ssd2 ... max-size=99999
4274 cache_dir rock /hdd3 ... min-size=100000
4275 cache_dir rock /ssd3 ... max-size=99999
4278 NAME: max_open_disk_fds
4280 LOC: Config.max_open_disk_fds
4282 DEFAULT_DOC: no limit
4284 To avoid having disk as the I/O bottleneck Squid can optionally
4285 bypass the on-disk cache if more than this amount of disk file
4286 descriptors are open.
4288 A value of 0 indicates no limit.
4291 NAME: cache_swap_low
4292 COMMENT: (percent, 0-100)
4295 LOC: Config.Swap.lowWaterMark
4297 The low-water mark for AUFS/UFS/diskd cache object eviction by
4298 the cache_replacement_policy algorithm.
4300 Removal begins when the swap (disk) usage of a cache_dir is
4301 above this low-water mark and attempts to maintain utilization
4302 near the low-water mark.
4304 As swap utilization increases towards the high-water mark set
4305 by cache_swap_high object eviction becomes more agressive.
4307 The value difference in percentages between low- and high-water
4308 marks represent an eviction rate of 300 objects per second and
4309 the rate continues to scale in agressiveness by multiples of
4310 this above the high-water mark.
4312 Defaults are 90% and 95%. If you have a large cache, 5% could be
4313 hundreds of MB. If this is the case you may wish to set these
4314 numbers closer together.
4316 See also cache_swap_high and cache_replacement_policy
4319 NAME: cache_swap_high
4320 COMMENT: (percent, 0-100)
4323 LOC: Config.Swap.highWaterMark
4325 The high-water mark for AUFS/UFS/diskd cache object eviction by
4326 the cache_replacement_policy algorithm.
4328 Removal begins when the swap (disk) usage of a cache_dir is
4329 above the low-water mark set by cache_swap_low and attempts to
4330 maintain utilization near the low-water mark.
4332 As swap utilization increases towards this high-water mark object
4333 eviction becomes more agressive.
4335 The value difference in percentages between low- and high-water
4336 marks represent an eviction rate of 300 objects per second and
4337 the rate continues to scale in agressiveness by multiples of
4338 this above the high-water mark.
4340 Defaults are 90% and 95%. If you have a large cache, 5% could be
4341 hundreds of MB. If this is the case you may wish to set these
4342 numbers closer together.
4344 See also cache_swap_low and cache_replacement_policy
4349 -----------------------------------------------------------------------------
4356 DEFAULT_DOC: The format definitions squid, common, combined, referrer, useragent are built in.
4360 logformat <name> <format specification>
4362 Defines an access log format.
4364 The <format specification> is a string with embedded % format codes
4366 % format codes all follow the same basic structure where all but
4367 the formatcode is optional. Output strings are automatically escaped
4368 as required according to their context and the output format
4369 modifiers are usually not needed, but can be specified if an explicit
4370 output format is desired.
4372 % ["|[|'|#|/] [-] [[0]width] [{arg}] formatcode [{arg}]
4374 " output in quoted string format
4375 [ output in squid text log format as used by log_mime_hdrs
4376 # output in URL quoted format
4377 / output in shell \-escaped format
4382 width minimum and/or maximum field width:
4383 [width_min][.width_max]
4384 When minimum starts with 0, the field is zero-padded.
4385 String values exceeding maximum width are truncated.
4387 {arg} argument such as header name etc. This field may be
4388 placed before or after the token, but not both at once.
4392 % a literal % character
4393 sn Unique sequence number per log line entry
4394 err_code The ID of an error response served by Squid or
4395 a similar internal error identifier.
4396 err_detail Additional err_code-dependent error information.
4397 note The annotation specified by the argument. Also
4398 logs the adaptation meta headers set by the
4399 adaptation_meta configuration parameter.
4400 If no argument given all annotations logged.
4401 The argument may include a separator to use with
4404 By default, multiple note values are separated with ","
4405 and multiple notes are separated with "\r\n".
4406 When logging named notes with %{name}note, the
4407 explicitly configured separator is used between note
4408 values. When logging all notes with %note, the
4409 explicitly configured separator is used between
4410 individual notes. There is currently no way to
4411 specify both value and notes separators when logging
4412 all notes with %note.
4414 Connection related format codes:
4416 >a Client source IP address
4418 >p Client source port
4419 >eui Client source EUI (MAC address, EUI-48 or EUI-64 identifier)
4420 >la Local IP address the client connected to
4421 >lp Local port number the client connected to
4422 >qos Client connection TOS/DSCP value set by Squid
4423 >nfmark Client connection netfilter mark set by Squid
4425 la Local listening IP address the client connection was connected to.
4426 lp Local listening port number the client connection was connected to.
4428 <a Server IP address of the last server or peer connection
4429 <A Server FQDN or peer name
4430 <p Server port number of the last server or peer connection
4431 <la Local IP address of the last server or peer connection
4432 <lp Local port number of the last server or peer connection
4433 <qos Server connection TOS/DSCP value set by Squid
4434 <nfmark Server connection netfilter mark set by Squid
4436 Time related format codes:
4438 ts Seconds since epoch
4439 tu subsecond time (milliseconds)
4440 tl Local time. Optional strftime format argument
4441 default %d/%b/%Y:%H:%M:%S %z
4442 tg GMT time. Optional strftime format argument
4443 default %d/%b/%Y:%H:%M:%S %z
4444 tr Response time (milliseconds)
4445 dt Total time spent making DNS lookups (milliseconds)
4446 tS Approximate master transaction start time in
4447 <full seconds since epoch>.<fractional seconds> format.
4448 Currently, Squid considers the master transaction
4449 started when a complete HTTP request header initiating
4450 the transaction is received from the client. This is
4451 the same value that Squid uses to calculate transaction
4452 response time when logging %tr to access.log. Currently,
4453 Squid uses millisecond resolution for %tS values,
4454 similar to the default access.log "current time" field
4457 Access Control related format codes:
4459 et Tag returned by external acl
4460 ea Log string returned by external acl
4461 un User name (any available)
4462 ul User name from authentication
4463 ue User name from external acl helper
4464 ui User name from ident
4465 un A user name. Expands to the first available name
4466 from the following list of information sources:
4467 - authenticated user name, like %ul
4468 - user name supplied by an external ACL, like %ue
4469 - SSL client name, like %us
4470 - ident user name, like %ui
4471 credentials Client credentials. The exact meaning depends on
4472 the authentication scheme: For Basic authentication,
4473 it is the password; for Digest, the realm sent by the
4474 client; for NTLM and Negotiate, the client challenge
4475 or client credentials prefixed with "YR " or "KK ".
4477 HTTP related format codes:
4481 [http::]rm Request method (GET/POST etc)
4482 [http::]>rm Request method from client
4483 [http::]<rm Request method sent to server or peer
4484 [http::]ru Request URL from client (historic, filtered for logging)
4485 [http::]>ru Request URL from client
4486 [http::]<ru Request URL sent to server or peer
4487 [http::]>rs Request URL scheme from client
4488 [http::]<rs Request URL scheme sent to server or peer
4489 [http::]>rd Request URL domain from client
4490 [http::]<rd Request URL domain sent to server or peer
4491 [http::]>rP Request URL port from client
4492 [http::]<rP Request URL port sent to server or peer
4493 [http::]rp Request URL path excluding hostname
4494 [http::]>rp Request URL path excluding hostname from client
4495 [http::]<rp Request URL path excluding hostname sent to server or peer
4496 [http::]rv Request protocol version
4497 [http::]>rv Request protocol version from client
4498 [http::]<rv Request protocol version sent to server or peer
4500 [http::]>h Original received request header.
4501 Usually differs from the request header sent by
4502 Squid, although most fields are often preserved.
4503 Accepts optional header field name/value filter
4504 argument using name[:[separator]element] format.
4505 [http::]>ha Received request header after adaptation and
4506 redirection (pre-cache REQMOD vectoring point).
4507 Usually differs from the request header sent by
4508 Squid, although most fields are often preserved.
4509 Optional header name argument as for >h
4513 [http::]<Hs HTTP status code received from the next hop
4514 [http::]>Hs HTTP status code sent to the client
4516 [http::]<h Reply header. Optional header name argument
4519 [http::]mt MIME content type
4524 [http::]st Total size of request + reply traffic with client
4525 [http::]>st Total size of request received from client.
4526 Excluding chunked encoding bytes.
4527 [http::]<st Total size of reply sent to client (after adaptation)
4529 [http::]>sh Size of request headers received from client
4530 [http::]<sh Size of reply headers sent to client (after adaptation)
4532 [http::]<sH Reply high offset sent
4533 [http::]<sS Upstream object size
4535 [http::]<bs Number of HTTP-equivalent message body bytes
4536 received from the next hop, excluding chunked
4537 transfer encoding and control messages.
4538 Generated FTP/Gopher listings are treated as
4543 [http::]<pt Peer response time in milliseconds. The timer starts
4544 when the last request byte is sent to the next hop
4545 and stops when the last response byte is received.
4546 [http::]<tt Total time in milliseconds. The timer
4547 starts with the first connect request (or write I/O)
4548 sent to the first selected peer. The timer stops
4549 with the last I/O with the last peer.
4551 Squid handling related format codes:
4553 Ss Squid request status (TCP_MISS etc)
4554 Sh Squid hierarchy status (DEFAULT_PARENT etc)
4556 SSL-related format codes:
4558 ssl::bump_mode SslBump decision for the transaction:
4560 For CONNECT requests that initiated bumping of
4561 a connection and for any request received on
4562 an already bumped connection, Squid logs the
4563 corresponding SslBump mode ("splice", "bump",
4564 "peek", "stare", "terminate", "server-first"
4565 or "client-first"). See the ssl_bump option
4566 for more information about these modes.
4568 A "none" token is logged for requests that
4569 triggered "ssl_bump" ACL evaluation matching
4572 In all other cases, a single dash ("-") is
4575 ssl::>sni SSL client SNI sent to Squid.
4578 The Subject field of the received client
4579 SSL certificate or a dash ('-') if Squid has
4580 received an invalid/malformed certificate or
4581 no certificate at all. Consider encoding the
4582 logged value because Subject often has spaces.
4585 The Issuer field of the received client
4586 SSL certificate or a dash ('-') if Squid has
4587 received an invalid/malformed certificate or
4588 no certificate at all. Consider encoding the
4589 logged value because Issuer often has spaces.
4592 The Subject field of the received server
4593 TLS certificate or a dash ('-') if this is
4594 not available. Consider encoding the logged
4595 value because Subject often has spaces.
4598 The Issuer field of the received server
4599 TLS certificate or a dash ('-') if this is
4600 not available. Consider encoding the logged
4601 value because Issuer often has spaces.
4604 The list of certificate validation errors
4605 detected by Squid (including OpenSSL and
4606 certificate validation helper components). The
4607 errors are listed in the discovery order. By
4608 default, the error codes are separated by ':'.
4609 Accepts an optional separator argument.
4611 %ssl::>negotiated_version The negotiated TLS version of the
4614 %ssl::<negotiated_version The negotiated TLS version of the
4615 last server or peer connection.
4617 %ssl::>received_hello_version The TLS version of the Hello
4618 message received from TLS client.
4620 %ssl::<received_hello_version The TLS version of the Hello
4621 message received from TLS server.
4623 %ssl::>received_supported_version The maximum TLS version
4624 supported by the TLS client.
4626 %ssl::<received_supported_version The maximum TLS version
4627 supported by the TLS server.
4629 %ssl::>negotiated_cipher The negotiated cipher of the
4632 %ssl::<negotiated_cipher The negotiated cipher of the
4633 last server or peer connection.
4635 If ICAP is enabled, the following code becomes available (as
4636 well as ICAP log codes documented with the icap_log option):
4638 icap::tt Total ICAP processing time for the HTTP
4639 transaction. The timer ticks when ICAP
4640 ACLs are checked and when ICAP
4641 transaction is in progress.
4643 If adaptation is enabled the following codes become available:
4645 adapt::<last_h The header of the last ICAP response or
4646 meta-information from the last eCAP
4647 transaction related to the HTTP transaction.
4648 Like <h, accepts an optional header name
4651 adapt::sum_trs Summed adaptation transaction response
4652 times recorded as a comma-separated list in
4653 the order of transaction start time. Each time
4654 value is recorded as an integer number,
4655 representing response time of one or more
4656 adaptation (ICAP or eCAP) transaction in
4657 milliseconds. When a failed transaction is
4658 being retried or repeated, its time is not
4659 logged individually but added to the
4660 replacement (next) transaction. See also:
4663 adapt::all_trs All adaptation transaction response times.
4664 Same as adaptation_strs but response times of
4665 individual transactions are never added
4666 together. Instead, all transaction response
4667 times are recorded individually.
4669 You can prefix adapt::*_trs format codes with adaptation
4670 service name in curly braces to record response time(s) specific
4671 to that service. For example: %{my_service}adapt::sum_trs
4673 The default formats available (which do not need re-defining) are:
4675 logformat squid %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %[un %Sh/%<a %mt
4676 logformat common %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st %Ss:%Sh
4677 logformat combined %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
4678 logformat referrer %ts.%03tu %>a %{Referer}>h %ru
4679 logformat useragent %>a [%tl] "%{User-Agent}>h"
4681 NOTE: When the log_mime_hdrs directive is set to ON.
4682 The squid, common and combined formats have a safely encoded copy
4683 of the mime headers appended to each line within a pair of brackets.
4685 NOTE: The common and combined formats are not quite true to the Apache definition.
4686 The logs from Squid contain an extra status and hierarchy code appended.
4690 NAME: access_log cache_access_log
4692 LOC: Config.Log.accesslogs
4693 DEFAULT_IF_NONE: daemon:@DEFAULT_ACCESS_LOG@ squid
4695 Configures whether and how Squid logs HTTP and ICP transactions.
4696 If access logging is enabled, a single line is logged for every
4697 matching HTTP or ICP request. The recommended directive formats are:
4699 access_log <module>:<place> [option ...] [acl acl ...]
4700 access_log none [acl acl ...]
4702 The following directive format is accepted but may be deprecated:
4703 access_log <module>:<place> [<logformat name> [acl acl ...]]
4705 In most cases, the first ACL name must not contain the '=' character
4706 and should not be equal to an existing logformat name. You can always
4707 start with an 'all' ACL to work around those restrictions.
4709 Will log to the specified module:place using the specified format (which
4710 must be defined in a logformat directive) those entries which match
4711 ALL the acl's specified (which must be defined in acl clauses).
4712 If no acl is specified, all requests will be logged to this destination.
4714 ===== Available options for the recommended directive format =====
4716 logformat=name Names log line format (either built-in or
4717 defined by a logformat directive). Defaults
4720 buffer-size=64KB Defines approximate buffering limit for log
4721 records (see buffered_logs). Squid should not
4722 keep more than the specified size and, hence,
4723 should flush records before the buffer becomes
4724 full to avoid overflows under normal
4725 conditions (the exact flushing algorithm is
4726 module-dependent though). The on-error option
4727 controls overflow handling.
4729 on-error=die|drop Defines action on unrecoverable errors. The
4730 'drop' action ignores (i.e., does not log)
4731 affected log records. The default 'die' action
4732 kills the affected worker. The drop action
4733 support has not been tested for modules other
4736 rotate=N Specifies the number of log file rotations to
4737 make when you run 'squid -k rotate'. The default
4738 is to obey the logfile_rotate directive. Setting
4739 rotate=0 will disable the file name rotation,
4740 but the log files are still closed and re-opened.
4741 This will enable you to rename the logfiles
4742 yourself just before sending the rotate signal.
4743 Only supported by the stdio module.
4745 ===== Modules Currently available =====
4747 none Do not log any requests matching these ACL.
4748 Do not specify Place or logformat name.
4750 stdio Write each log line to disk immediately at the completion of
4752 Place: the filename and path to be written.
4754 daemon Very similar to stdio. But instead of writing to disk the log
4755 line is passed to a daemon helper for asychronous handling instead.
4756 Place: varies depending on the daemon.
4758 log_file_daemon Place: the file name and path to be written.
4760 syslog To log each request via syslog facility.
4761 Place: The syslog facility and priority level for these entries.
4762 Place Format: facility.priority
4764 where facility could be any of:
4765 authpriv, daemon, local0 ... local7 or user.
4767 And priority could be any of:
4768 err, warning, notice, info, debug.
4770 udp To send each log line as text data to a UDP receiver.
4771 Place: The destination host name or IP and port.
4772 Place Format: //host:port
4774 tcp To send each log line as text data to a TCP receiver.
4775 Lines may be accumulated before sending (see buffered_logs).
4776 Place: The destination host name or IP and port.
4777 Place Format: //host:port
4780 access_log daemon:@DEFAULT_ACCESS_LOG@ squid
4786 LOC: Config.Log.icaplogs
4789 ICAP log files record ICAP transaction summaries, one line per
4792 The icap_log option format is:
4793 icap_log <filepath> [<logformat name> [acl acl ...]]
4794 icap_log none [acl acl ...]]
4796 Please see access_log option documentation for details. The two
4797 kinds of logs share the overall configuration approach and many
4800 ICAP processing of a single HTTP message or transaction may
4801 require multiple ICAP transactions. In such cases, multiple
4802 ICAP transaction log lines will correspond to a single access
4805 ICAP log supports many access.log logformat %codes. In ICAP context,
4806 HTTP message-related %codes are applied to the HTTP message embedded
4807 in an ICAP message. Logformat "%http::>..." codes are used for HTTP
4808 messages embedded in ICAP requests while "%http::<..." codes are used
4809 for HTTP messages embedded in ICAP responses. For example:
4811 http::>h To-be-adapted HTTP message headers sent by Squid to
4812 the ICAP service. For REQMOD transactions, these are
4813 HTTP request headers. For RESPMOD, these are HTTP
4814 response headers, but Squid currently cannot log them
4815 (i.e., %http::>h will expand to "-" for RESPMOD).
4817 http::<h Adapted HTTP message headers sent by the ICAP
4818 service to Squid (i.e., HTTP request headers in regular
4819 REQMOD; HTTP response headers in RESPMOD and during
4820 request satisfaction in REQMOD).
4822 ICAP OPTIONS transactions do not embed HTTP messages.
4824 Several logformat codes below deal with ICAP message bodies. An ICAP
4825 message body, if any, typically includes a complete HTTP message
4826 (required HTTP headers plus optional HTTP message body). When
4827 computing HTTP message body size for these logformat codes, Squid
4828 either includes or excludes chunked encoding overheads; see
4829 code-specific documentation for details.
4831 For Secure ICAP services, all size-related information is currently
4832 computed before/after TLS encryption/decryption, as if TLS was not
4835 The following format codes are also available for ICAP logs:
4837 icap::<A ICAP server IP address. Similar to <A.
4839 icap::<service_name ICAP service name from the icap_service
4840 option in Squid configuration file.
4842 icap::ru ICAP Request-URI. Similar to ru.
4844 icap::rm ICAP request method (REQMOD, RESPMOD, or
4845 OPTIONS). Similar to existing rm.
4847 icap::>st The total size of the ICAP request sent to the ICAP
4848 server (ICAP headers + ICAP body), including chunking
4851 icap::<st The total size of the ICAP response received from the
4852 ICAP server (ICAP headers + ICAP body), including
4853 chunking metadata (if any).
4855 icap::<bs The size of the ICAP response body received from the
4856 ICAP server, excluding chunking metadata (if any).
4858 icap::tr Transaction response time (in
4859 milliseconds). The timer starts when
4860 the ICAP transaction is created and
4861 stops when the transaction is completed.
4864 icap::tio Transaction I/O time (in milliseconds). The
4865 timer starts when the first ICAP request
4866 byte is scheduled for sending. The timers
4867 stops when the last byte of the ICAP response
4870 icap::to Transaction outcome: ICAP_ERR* for all
4871 transaction errors, ICAP_OPT for OPTION
4872 transactions, ICAP_ECHO for 204
4873 responses, ICAP_MOD for message
4874 modification, and ICAP_SAT for request
4875 satisfaction. Similar to Ss.
4877 icap::Hs ICAP response status code. Similar to Hs.
4879 icap::>h ICAP request header(s). Similar to >h.
4881 icap::<h ICAP response header(s). Similar to <h.
4883 The default ICAP log format, which can be used without an explicit
4884 definition, is called icap_squid:
4886 logformat icap_squid %ts.%03tu %6icap::tr %>A %icap::to/%03icap::Hs %icap::<st %icap::rm %icap::ru %un -/%icap::<A -
4888 See also: logformat and %adapt::<last_h
4891 NAME: logfile_daemon
4893 DEFAULT: @DEFAULT_LOGFILED@
4894 LOC: Log::TheConfig.logfile_daemon
4896 Specify the path to the logfile-writing daemon. This daemon is
4897 used to write the access and store logs, if configured.
4899 Squid sends a number of commands to the log daemon:
4900 L<data>\n - logfile data
4905 r<n>\n - set rotate count to <n>
4906 b<n>\n - 1 = buffer output, 0 = don't buffer output
4908 No responses is expected.
4911 NAME: stats_collection
4913 LOC: Config.accessList.stats_collection
4915 DEFAULT_DOC: Allow logging for all transactions.
4916 COMMENT: allow|deny acl acl...
4918 This options allows you to control which requests gets accounted
4919 in performance counters.
4921 This clause only supports fast acl types.
4922 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4925 NAME: cache_store_log
4928 LOC: Config.Log.store
4930 Logs the activities of the storage manager. Shows which
4931 objects are ejected from the cache, and which objects are
4932 saved and for how long.
4933 There are not really utilities to analyze this data, so you can safely
4934 disable it (the default).
4936 Store log uses modular logging outputs. See access_log for the list
4937 of modules supported.
4940 cache_store_log stdio:@DEFAULT_STORE_LOG@
4941 cache_store_log daemon:@DEFAULT_STORE_LOG@
4944 NAME: cache_swap_state cache_swap_log
4946 LOC: Config.Log.swap
4948 DEFAULT_DOC: Store the journal inside its cache_dir
4950 Location for the cache "swap.state" file. This index file holds
4951 the metadata of objects saved on disk. It is used to rebuild
4952 the cache during startup. Normally this file resides in each
4953 'cache_dir' directory, but you may specify an alternate
4954 pathname here. Note you must give a full filename, not just
4955 a directory. Since this is the index for the whole object
4956 list you CANNOT periodically rotate it!
4958 If %s can be used in the file name it will be replaced with a
4959 a representation of the cache_dir name where each / is replaced
4960 with '.'. This is needed to allow adding/removing cache_dir
4961 lines when cache_swap_log is being used.
4963 If have more than one 'cache_dir', and %s is not used in the name
4964 these swap logs will have names such as:
4970 The numbered extension (which is added automatically)
4971 corresponds to the order of the 'cache_dir' lines in this
4972 configuration file. If you change the order of the 'cache_dir'
4973 lines in this file, these index files will NOT correspond to
4974 the correct 'cache_dir' entry (unless you manually rename
4975 them). We recommend you do NOT use this option. It is
4976 better to keep these index files in each 'cache_dir' directory.
4979 NAME: logfile_rotate
4982 LOC: Config.Log.rotateNumber
4984 Specifies the default number of logfile rotations to make when you
4985 type 'squid -k rotate'. The default is 10, which will rotate
4986 with extensions 0 through 9. Setting logfile_rotate to 0 will
4987 disable the file name rotation, but the logfiles are still closed
4988 and re-opened. This will enable you to rename the logfiles
4989 yourself just before sending the rotate signal.
4991 Note, from Squid-3.1 this option is only a default for cache.log,
4992 that log can be rotated separately by using debug_options.
4994 Note, from Squid-4 this option is only a default for access.log
4995 recorded by stdio: module. Those logs can be rotated separately by
4996 using the rotate=N option on their access_log directive.
4998 Note, the 'squid -k rotate' command normally sends a USR1
4999 signal to the running squid process. In certain situations
5000 (e.g. on Linux with Async I/O), USR1 is used for other
5001 purposes, so -k rotate uses another signal. It is best to get
5002 in the habit of using 'squid -k rotate' instead of 'kill -USR1
5009 DEFAULT: @DEFAULT_MIME_TABLE@
5010 LOC: Config.mimeTablePathname
5012 Path to Squid's icon configuration file.
5014 You shouldn't need to change this, but the default file contains
5015 examples and formatting information if you do.
5021 LOC: Config.onoff.log_mime_hdrs
5024 The Cache can record both the request and the response MIME
5025 headers for each HTTP transaction. The headers are encoded
5026 safely and will appear as two bracketed fields at the end of
5027 the access log (for either the native or httpd-emulated log
5028 formats). To enable this logging set log_mime_hdrs to 'on'.
5033 DEFAULT: @DEFAULT_PID_FILE@
5034 LOC: Config.pidFilename
5036 A filename to write the process-id to. To disable, enter "none".
5039 NAME: client_netmask
5041 LOC: Config.Addrs.client_netmask
5043 DEFAULT_DOC: Log full client IP address
5045 A netmask for client addresses in logfiles and cachemgr output.
5046 Change this to protect the privacy of your cache clients.
5047 A netmask of 255.255.255.0 will log all IP's in that range with
5048 the last digit set to '0'.
5051 NAME: strip_query_terms
5053 LOC: Config.onoff.strip_query_terms
5056 By default, Squid strips query terms from requested URLs before
5057 logging. This protects your user's privacy and reduces log size.
5059 When investigating HIT/MISS or other caching behaviour you
5060 will need to disable this to see the full URL used by Squid.
5067 LOC: Config.onoff.buffered_logs
5069 Whether to write/send access_log records ASAP or accumulate them and
5070 then write/send them in larger chunks. Buffering may improve
5071 performance because it decreases the number of I/Os. However,
5072 buffering increases the delay before log records become available to
5073 the final recipient (e.g., a disk file or logging daemon) and,
5074 hence, increases the risk of log records loss.
5076 Note that even when buffered_logs are off, Squid may have to buffer
5077 records if it cannot write/send them immediately due to pending I/Os
5078 (e.g., the I/O writing the previous log record) or connectivity loss.
5080 Currently honored by 'daemon' and 'tcp' access_log modules only.
5083 NAME: netdb_filename
5085 DEFAULT: stdio:@DEFAULT_NETDB_FILE@
5086 LOC: Config.netdbFilename
5089 Where Squid stores it's netdb journal.
5090 When enabled this journal preserves netdb state between restarts.
5092 To disable, enter "none".
5096 OPTIONS FOR TROUBLESHOOTING
5097 -----------------------------------------------------------------------------
5102 DEFAULT_IF_NONE: @DEFAULT_CACHE_LOG@
5103 LOC: Debug::cache_log
5105 Squid administrative logging file.
5107 This is where general information about Squid behavior goes. You can
5108 increase the amount of data logged to this file and how often it is
5109 rotated with "debug_options"
5115 DEFAULT_DOC: Log all critical and important messages.
5116 LOC: Debug::debugOptions
5118 Logging options are set as section,level where each source file
5119 is assigned a unique section. Lower levels result in less
5120 output, Full debugging (level 9) can result in a very large
5121 log file, so be careful.
5123 The magic word "ALL" sets debugging levels for all sections.
5124 The default is to run with "ALL,1" to record important warnings.
5126 The rotate=N option can be used to keep more or less of these logs
5127 than would otherwise be kept by logfile_rotate.
5128 For most uses a single log should be enough to monitor current
5129 events affecting Squid.
5134 LOC: Config.coredump_dir
5135 DEFAULT_IF_NONE: none
5136 DEFAULT_DOC: Use the directory from where Squid was started.
5138 By default Squid leaves core files in the directory from where
5139 it was started. If you set 'coredump_dir' to a directory
5140 that exists, Squid will chdir() to that directory at startup
5141 and coredump files will be left there.
5145 # Leave coredumps in the first cache dir
5146 coredump_dir @DEFAULT_SWAP_DIR@
5152 OPTIONS FOR FTP GATEWAYING
5153 -----------------------------------------------------------------------------
5159 LOC: Config.Ftp.anon_user
5161 If you want the anonymous login password to be more informative
5162 (and enable the use of picky FTP servers), set this to something
5163 reasonable for your domain, like wwwuser@somewhere.net
5165 The reason why this is domainless by default is the
5166 request can be made on the behalf of a user in any domain,
5167 depending on how the cache is used.
5168 Some FTP server also validate the email address is valid
5169 (for example perl.com).
5175 LOC: Config.Ftp.passive
5177 If your firewall does not allow Squid to use passive
5178 connections, turn off this option.
5180 Use of ftp_epsv_all option requires this to be ON.
5186 LOC: Config.Ftp.epsv_all
5188 FTP Protocol extensions permit the use of a special "EPSV ALL" command.
5190 NATs may be able to put the connection on a "fast path" through the
5191 translator, as the EPRT command will never be used and therefore,
5192 translation of the data portion of the segments will never be needed.
5194 When a client only expects to do two-way FTP transfers this may be
5196 If squid finds that it must do a three-way FTP transfer after issuing
5197 an EPSV ALL command, the FTP session will fail.
5199 If you have any doubts about this option do not use it.
5200 Squid will nicely attempt all other connection methods.
5202 Requires ftp_passive to be ON (default) for any effect.
5208 LOC: Config.accessList.ftp_epsv
5210 FTP Protocol extensions permit the use of a special "EPSV" command.
5212 NATs may be able to put the connection on a "fast path" through the
5213 translator using EPSV, as the EPRT command will never be used
5214 and therefore, translation of the data portion of the segments
5215 will never be needed.
5217 EPSV is often required to interoperate with FTP servers on IPv6
5218 networks. On the other hand, it may break some IPv4 servers.
5220 By default, EPSV may try EPSV with any FTP server. To fine tune
5221 that decision, you may restrict EPSV to certain clients or servers
5224 ftp_epsv allow|deny al1 acl2 ...
5226 WARNING: Disabling EPSV may cause problems with external NAT and IPv6.
5228 Only fast ACLs are supported.
5229 Requires ftp_passive to be ON (default) for any effect.
5235 LOC: Config.Ftp.eprt
5237 FTP Protocol extensions permit the use of a special "EPRT" command.
5239 This extension provides a protocol neutral alternative to the
5240 IPv4-only PORT command. When supported it enables active FTP data
5241 channels over IPv6 and efficient NAT handling.
5243 Turning this OFF will prevent EPRT being attempted and will skip
5244 straight to using PORT for IPv4 servers.
5246 Some devices are known to not handle this extension correctly and
5247 may result in crashes. Devices which suport EPRT enough to fail
5248 cleanly will result in Squid attempting PORT anyway. This directive
5249 should only be disabled when EPRT results in device failures.
5251 WARNING: Doing so will convert Squid back to the old behavior with all
5252 the related problems with external NAT devices/layers and IPv4-only FTP.
5255 NAME: ftp_sanitycheck
5258 LOC: Config.Ftp.sanitycheck
5260 For security and data integrity reasons Squid by default performs
5261 sanity checks of the addresses of FTP data connections ensure the
5262 data connection is to the requested server. If you need to allow
5263 FTP connections to servers using another IP address for the data
5264 connection turn this off.
5267 NAME: ftp_telnet_protocol
5270 LOC: Config.Ftp.telnet
5272 The FTP protocol is officially defined to use the telnet protocol
5273 as transport channel for the control connection. However, many
5274 implementations are broken and does not respect this aspect of
5277 If you have trouble accessing files with ASCII code 255 in the
5278 path or similar problems involving this ASCII code you can
5279 try setting this directive to off. If that helps, report to the
5280 operator of the FTP server in question that their FTP server
5281 is broken and does not follow the FTP standard.
5285 OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
5286 -----------------------------------------------------------------------------
5291 DEFAULT: @DEFAULT_DISKD@
5292 LOC: Config.Program.diskd
5294 Specify the location of the diskd executable.
5295 Note this is only useful if you have compiled in
5296 diskd as one of the store io modules.
5299 NAME: unlinkd_program
5302 DEFAULT: @DEFAULT_UNLINKD@
5303 LOC: Config.Program.unlinkd
5305 Specify the location of the executable for file deletion process.
5308 NAME: pinger_program
5311 DEFAULT: @DEFAULT_PINGER@
5314 Specify the location of the executable for the pinger process.
5323 Control whether the pinger is active at run-time.
5324 Enables turning ICMP pinger on and off with a simple
5325 squid -k reconfigure.
5330 OPTIONS FOR URL REWRITING
5331 -----------------------------------------------------------------------------
5334 NAME: url_rewrite_program redirect_program
5336 LOC: Config.Program.redirect
5339 Specify the location of the executable URL rewriter to use.
5340 Since they can perform almost any function there isn't one included.
5342 For each requested URL, the rewriter will receive on line with the format
5344 [channel-ID <SP>] URL [<SP> extras]<NL>
5346 See url_rewrite_extras on how to send "extras" with optional values to
5348 After processing the request the helper must reply using the following format:
5350 [channel-ID <SP>] result [<SP> kv-pairs]
5352 The result code can be:
5354 OK status=30N url="..."
5355 Redirect the URL to the one supplied in 'url='.
5356 'status=' is optional and contains the status code to send
5357 the client in Squids HTTP response. It must be one of the
5358 HTTP redirect status codes: 301, 302, 303, 307, 308.
5359 When no status is given Squid will use 302.
5361 OK rewrite-url="..."
5362 Rewrite the URL to the one supplied in 'rewrite-url='.
5363 The new URL is fetched directly by Squid and returned to
5364 the client as the response to its request.
5367 When neither of url= and rewrite-url= are sent Squid does
5371 Do not change the URL.
5374 An internal error occurred in the helper, preventing
5375 a result being identified. The 'message=' key name is
5376 reserved for delivering a log message.
5379 In addition to the above kv-pairs Squid also understands the following
5380 optional kv-pairs received from URL rewriters:
5382 Associates a TAG with the client TCP connection.
5383 The TAG is treated as a regular annotation but persists across
5384 future requests on the client connection rather than just the
5385 current request. A helper may update the TAG during subsequent
5386 requests be returning a new kv-pair.
5388 When using the concurrency= option the protocol is changed by
5389 introducing a query channel tag in front of the request/response.
5390 The query channel tag is a number between 0 and concurrency-1.
5391 This value must be echoed back unchanged to Squid as the first part
5392 of the response relating to its request.
5394 WARNING: URL re-writing ability should be avoided whenever possible.
5395 Use the URL redirect form of response instead.
5397 Re-write creates a difference in the state held by the client
5398 and server. Possibly causing confusion when the server response
5399 contains snippets of its view state. Embeded URLs, response
5400 and content Location headers, etc. are not re-written by this
5403 By default, a URL rewriter is not used.
5406 NAME: url_rewrite_children redirect_children
5407 TYPE: HelperChildConfig
5408 DEFAULT: 20 startup=0 idle=1 concurrency=0
5409 LOC: Config.redirectChildren
5411 The maximum number of redirector processes to spawn. If you limit
5412 it too few Squid will have to wait for them to process a backlog of
5413 URLs, slowing it down. If you allow too many they will use RAM
5414 and other system resources noticably.
5416 The startup= and idle= options allow some measure of skew in your
5421 Sets a minimum of how many processes are to be spawned when Squid
5422 starts or reconfigures. When set to zero the first request will
5423 cause spawning of the first child process to handle it.
5425 Starting too few will cause an initial slowdown in traffic as Squid
5426 attempts to simultaneously spawn enough processes to cope.
5430 Sets a minimum of how many processes Squid is to try and keep available
5431 at all times. When traffic begins to rise above what the existing
5432 processes can handle this many more will be spawned up to the maximum
5433 configured. A minimum setting of 1 is required.
5437 The number of requests each redirector helper can handle in
5438 parallel. Defaults to 0 which indicates the redirector
5439 is a old-style single threaded redirector.
5441 When this directive is set to a value >= 1 then the protocol
5442 used to communicate with the helper is modified to include
5443 an ID in front of the request/response. The ID from the request
5444 must be echoed back with the response to that request.
5448 Sets the maximum number of queued requests to N. The default maximum
5449 is 2*numberofchildren. If the queued requests exceed queue size and
5450 redirector_bypass configuration option is set, then redirector is bypassed.
5451 Otherwise, Squid is allowed to temporarily exceed the configured maximum,
5452 marking the affected helper as "overloaded". If the helper overload lasts
5453 more than 3 minutes, the action prescribed by the on-persistent-overload
5456 on-persistent-overload=action
5458 Specifies Squid reaction to a new helper request arriving when the helper
5459 has been overloaded for more that 3 minutes already. The number of queued
5460 requests determines whether the helper is overloaded (see the queue-size
5463 Two actions are supported:
5465 die Squid worker quits. This is the default behavior.
5467 ERR Squid treats the helper request as if it was
5468 immediately submitted, and the helper immediately
5469 replied with an ERR response. This action has no effect
5470 on the already queued and in-progress helper requests.
5473 NAME: url_rewrite_host_header redirect_rewrites_host_header
5476 LOC: Config.onoff.redir_rewrites_host
5478 To preserve same-origin security policies in browsers and
5479 prevent Host: header forgery by redirectors Squid rewrites
5480 any Host: header in redirected requests.
5482 If you are running an accelerator this may not be a wanted
5483 effect of a redirector. This directive enables you disable
5484 Host: alteration in reverse-proxy traffic.
5486 WARNING: Entries are cached on the result of the URL rewriting
5487 process, so be careful if you have domain-virtual hosts.
5489 WARNING: Squid and other software verifies the URL and Host
5490 are matching, so be careful not to relay through other proxies
5491 or inspecting firewalls with this disabled.
5494 NAME: url_rewrite_access redirector_access
5497 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
5498 LOC: Config.accessList.redirector
5500 If defined, this access list specifies which requests are
5501 sent to the redirector processes.
5503 This clause supports both fast and slow acl types.
5504 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5507 NAME: url_rewrite_bypass redirector_bypass
5509 LOC: Config.onoff.redirector_bypass
5512 When this is 'on', a request will not go through the
5513 redirector if all the helpers are busy. If this is 'off' and the
5514 redirector queue grows too large, the action is prescribed by the
5515 on-persistent-overload option. You should only enable this if the
5516 redirectors are not critical to your caching system. If you use
5517 redirectors for access control, and you enable this option,
5518 users may have access to pages they should not
5519 be allowed to request.
5520 This options sets default queue-size option of the url_rewrite_children
5524 NAME: url_rewrite_extras
5525 TYPE: TokenOrQuotedString
5526 LOC: Config.redirector_extras
5527 DEFAULT: "%>a/%>A %un %>rm myip=%la myport=%lp"
5529 Specifies a string to be append to request line format for the
5530 rewriter helper. "Quoted" format values may contain spaces and
5531 logformat %macros. In theory, any logformat %macro can be used.
5532 In practice, a %macro expands as a dash (-) if the helper request is
5533 sent before the required macro information is available to Squid.
5536 NAME: url_rewrite_timeout
5537 TYPE: UrlHelperTimeout
5538 LOC: Config.onUrlRewriteTimeout
5540 DEFAULT_DOC: Squid waits for the helper response forever
5542 Squid times active requests to redirector. The timeout value and Squid
5543 reaction to a timed out request are configurable using the following
5546 url_rewrite_timeout timeout time-units on_timeout=<action> [response=<quoted-response>]
5548 supported timeout actions:
5549 fail Squid return a ERR_GATEWAY_FAILURE error page
5551 bypass Do not re-write the URL
5553 retry Send the lookup to the helper again
5555 use_configured_response
5556 Use the <quoted-response> as helper response
5560 OPTIONS FOR STORE ID
5561 -----------------------------------------------------------------------------
5564 NAME: store_id_program storeurl_rewrite_program
5566 LOC: Config.Program.store_id
5569 Specify the location of the executable StoreID helper to use.
5570 Since they can perform almost any function there isn't one included.
5572 For each requested URL, the helper will receive one line with the format
5574 [channel-ID <SP>] URL [<SP> extras]<NL>
5577 After processing the request the helper must reply using the following format:
5579 [channel-ID <SP>] result [<SP> kv-pairs]
5581 The result code can be:
5584 Use the StoreID supplied in 'store-id='.
5587 The default is to use HTTP request URL as the store ID.
5590 An internal error occured in the helper, preventing
5591 a result being identified.
5593 In addition to the above kv-pairs Squid also understands the following
5594 optional kv-pairs received from URL rewriters:
5596 Associates a TAG with the client TCP connection.
5597 Please see url_rewrite_program related documentation for this
5600 Helper programs should be prepared to receive and possibly ignore
5601 additional whitespace-separated tokens on each input line.
5603 When using the concurrency= option the protocol is changed by
5604 introducing a query channel tag in front of the request/response.
5605 The query channel tag is a number between 0 and concurrency-1.
5606 This value must be echoed back unchanged to Squid as the first part
5607 of the response relating to its request.
5609 NOTE: when using StoreID refresh_pattern will apply to the StoreID
5610 returned from the helper and not the URL.
5612 WARNING: Wrong StoreID value returned by a careless helper may result
5613 in the wrong cached response returned to the user.
5615 By default, a StoreID helper is not used.
5618 NAME: store_id_extras
5619 TYPE: TokenOrQuotedString
5620 LOC: Config.storeId_extras
5621 DEFAULT: "%>a/%>A %un %>rm myip=%la myport=%lp"
5623 Specifies a string to be append to request line format for the
5624 StoreId helper. "Quoted" format values may contain spaces and
5625 logformat %macros. In theory, any logformat %macro can be used.
5626 In practice, a %macro expands as a dash (-) if the helper request is
5627 sent before the required macro information is available to Squid.
5630 NAME: store_id_children storeurl_rewrite_children
5631 TYPE: HelperChildConfig
5632 DEFAULT: 20 startup=0 idle=1 concurrency=0
5633 LOC: Config.storeIdChildren
5635 The maximum number of StoreID helper processes to spawn. If you limit
5636 it too few Squid will have to wait for them to process a backlog of
5637 requests, slowing it down. If you allow too many they will use RAM
5638 and other system resources noticably.
5640 The startup= and idle= options allow some measure of skew in your
5645 Sets a minimum of how many processes are to be spawned when Squid
5646 starts or reconfigures. When set to zero the first request will
5647 cause spawning of the first child process to handle it.
5649 Starting too few will cause an initial slowdown in traffic as Squid
5650 attempts to simultaneously spawn enough processes to cope.
5654 Sets a minimum of how many processes Squid is to try and keep available
5655 at all times. When traffic begins to rise above what the existing
5656 processes can handle this many more will be spawned up to the maximum
5657 configured. A minimum setting of 1 is required.
5661 The number of requests each storeID helper can handle in
5662 parallel. Defaults to 0 which indicates the helper
5663 is a old-style single threaded program.
5665 When this directive is set to a value >= 1 then the protocol
5666 used to communicate with the helper is modified to include
5667 an ID in front of the request/response. The ID from the request
5668 must be echoed back with the response to that request.
5672 Sets the maximum number of queued requests to N. The default maximum
5673 is 2*numberofchildren. If the queued requests exceed queue size and
5674 redirector_bypass configuration option is set, then redirector is bypassed.
5675 Otherwise, Squid is allowed to temporarily exceed the configured maximum,
5676 marking the affected helper as "overloaded". If the helper overload lasts
5677 more than 3 minutes, the action prescribed by the on-persistent-overload
5680 on-persistent-overload=action
5682 Specifies Squid reaction to a new helper request arriving when the helper
5683 has been overloaded for more that 3 minutes already. The number of queued
5684 requests determines whether the helper is overloaded (see the queue-size
5687 Two actions are supported:
5689 die Squid worker quits. This is the default behavior.
5691 ERR Squid treats the helper request as if it was
5692 immediately submitted, and the helper immediately
5693 replied with an ERR response. This action has no effect
5694 on the already queued and in-progress helper requests.
5697 NAME: store_id_access storeurl_rewrite_access
5700 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
5701 LOC: Config.accessList.store_id
5703 If defined, this access list specifies which requests are
5704 sent to the StoreID processes. By default all requests
5707 This clause supports both fast and slow acl types.
5708 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5711 NAME: store_id_bypass storeurl_rewrite_bypass
5713 LOC: Config.onoff.store_id_bypass
5716 When this is 'on', a request will not go through the
5717 helper if all helpers are busy. If this is 'off' and the helper
5718 queue grows too large, the action is prescribed by the
5719 on-persistent-overload option. You should only enable this if the
5720 helpers are not critical to your caching system. If you use
5721 helpers for critical caching components, and you enable this
5722 option, users may not get objects from cache.
5723 This options sets default queue-size option of the store_id_children
5728 OPTIONS FOR TUNING THE CACHE
5729 -----------------------------------------------------------------------------
5732 NAME: cache no_cache
5735 DEFAULT_DOC: By default, this directive is unused and has no effect.
5736 LOC: Config.accessList.noCache
5738 Requests denied by this directive will not be served from the cache
5739 and their responses will not be stored in the cache. This directive
5740 has no effect on other transactions and on already cached responses.
5742 This clause supports both fast and slow acl types.
5743 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5745 This and the two other similar caching directives listed below are
5746 checked at different transaction processing stages, have different
5747 access to response information, affect different cache operations,
5748 and differ in slow ACLs support:
5750 * cache: Checked before Squid makes a hit/miss determination.
5751 No access to reply information!
5752 Denies both serving a hit and storing a miss.
5753 Supports both fast and slow ACLs.
5754 * send_hit: Checked after a hit was detected.
5755 Has access to reply (hit) information.
5756 Denies serving a hit only.
5757 Supports fast ACLs only.
5758 * store_miss: Checked before storing a cachable miss.
5759 Has access to reply (miss) information.
5760 Denies storing a miss only.
5761 Supports fast ACLs only.
5763 If you are not sure which of the three directives to use, apply the
5764 following decision logic:
5766 * If your ACL(s) are of slow type _and_ need response info, redesign.
5767 Squid does not support that particular combination at this time.
5769 * If your directive ACL(s) are of slow type, use "cache"; and/or
5770 * if your directive ACL(s) need no response info, use "cache".
5772 * If you do not want the response cached, use store_miss; and/or
5773 * if you do not want a hit on a cached response, use send_hit.
5779 DEFAULT_DOC: By default, this directive is unused and has no effect.
5780 LOC: Config.accessList.sendHit
5782 Responses denied by this directive will not be served from the cache
5783 (but may still be cached, see store_miss). This directive has no
5784 effect on the responses it allows and on the cached objects.
5786 Please see the "cache" directive for a summary of differences among
5787 store_miss, send_hit, and cache directives.
5789 Unlike the "cache" directive, send_hit only supports fast acl
5790 types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5794 # apply custom Store ID mapping to some URLs
5795 acl MapMe dstdomain .c.example.com
5796 store_id_program ...
5797 store_id_access allow MapMe
5799 # but prevent caching of special responses
5800 # such as 302 redirects that cause StoreID loops
5801 acl Ordinary http_status 200-299
5802 store_miss deny MapMe !Ordinary
5804 # and do not serve any previously stored special responses
5805 # from the cache (in case they were already cached before
5806 # the above store_miss rule was in effect).
5807 send_hit deny MapMe !Ordinary
5813 DEFAULT_DOC: By default, this directive is unused and has no effect.
5814 LOC: Config.accessList.storeMiss
5816 Responses denied by this directive will not be cached (but may still
5817 be served from the cache, see send_hit). This directive has no
5818 effect on the responses it allows and on the already cached responses.
5820 Please see the "cache" directive for a summary of differences among
5821 store_miss, send_hit, and cache directives. See the
5822 send_hit directive for a usage example.
5824 Unlike the "cache" directive, store_miss only supports fast acl
5825 types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5831 LOC: Config.maxStale
5834 This option puts an upper limit on how stale content Squid
5835 will serve from the cache if cache validation fails.
5836 Can be overriden by the refresh_pattern max-stale option.
5839 NAME: refresh_pattern
5840 TYPE: refreshpattern
5844 usage: refresh_pattern [-i] regex min percent max [options]
5846 By default, regular expressions are CASE-SENSITIVE. To make
5847 them case-insensitive, use the -i option.
5849 'Min' is the time (in minutes) an object without an explicit
5850 expiry time should be considered fresh. The recommended
5851 value is 0, any higher values may cause dynamic applications
5852 to be erroneously cached unless the application designer
5853 has taken the appropriate actions.
5855 'Percent' is a percentage of the objects age (time since last
5856 modification age) an object without explicit expiry time
5857 will be considered fresh.
5859 'Max' is an upper limit on how long objects without an explicit
5860 expiry time will be considered fresh. The value is also used
5861 to form Cache-Control: max-age header for a request sent from
5862 Squid to origin/parent.
5864 options: override-expire
5874 override-expire enforces min age even if the server
5875 sent an explicit expiry time (e.g., with the
5876 Expires: header or Cache-Control: max-age). Doing this
5877 VIOLATES the HTTP standard. Enabling this feature
5878 could make you liable for problems which it causes.
5880 Note: override-expire does not enforce staleness - it only extends
5881 freshness / min. If the server returns a Expires time which
5882 is longer than your max time, Squid will still consider
5883 the object fresh for that period of time.
5885 override-lastmod enforces min age even on objects
5886 that were modified recently.
5888 reload-into-ims changes a client no-cache or ``reload''
5889 request for a cached entry into a conditional request using
5890 If-Modified-Since and/or If-None-Match headers, provided the
5891 cached entry has a Last-Modified and/or a strong ETag header.
5892 Doing this VIOLATES the HTTP standard. Enabling this feature
5893 could make you liable for problems which it causes.
5895 ignore-reload ignores a client no-cache or ``reload''
5896 header. Doing this VIOLATES the HTTP standard. Enabling
5897 this feature could make you liable for problems which
5900 ignore-no-store ignores any ``Cache-control: no-store''
5901 headers received from a server. Doing this VIOLATES
5902 the HTTP standard. Enabling this feature could make you
5903 liable for problems which it causes.
5905 ignore-private ignores any ``Cache-control: private''
5906 headers received from a server. Doing this VIOLATES
5907 the HTTP standard. Enabling this feature could make you
5908 liable for problems which it causes.
5910 refresh-ims causes squid to contact the origin server
5911 when a client issues an If-Modified-Since request. This
5912 ensures that the client will receive an updated version
5913 if one is available.
5915 store-stale stores responses even if they don't have explicit
5916 freshness or a validator (i.e., Last-Modified or an ETag)
5917 present, or if they're already stale. By default, Squid will
5918 not cache such responses because they usually can't be
5919 reused. Note that such responses will be stale by default.
5921 max-stale=NN provide a maximum staleness factor. Squid won't
5922 serve objects more stale than this even if it failed to
5923 validate the object. Default: use the max_stale global limit.
5925 Basically a cached object is:
5927 FRESH if expire > now, else STALE
5929 FRESH if lm-factor < percent, else STALE
5933 The refresh_pattern lines are checked in the order listed here.
5934 The first entry which matches is used. If none of the entries
5935 match the default will be used.
5937 Note, you must uncomment all the default lines if you want
5938 to change one. The default setting is only active if none is
5944 # Add any of your own refresh_pattern entries above these.
5946 refresh_pattern ^ftp: 1440 20% 10080
5947 refresh_pattern ^gopher: 1440 0% 1440
5948 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0
5949 refresh_pattern . 0 20% 4320
5953 NAME: quick_abort_min
5957 LOC: Config.quickAbort.min
5960 NAME: quick_abort_max
5964 LOC: Config.quickAbort.max
5967 NAME: quick_abort_pct
5971 LOC: Config.quickAbort.pct
5973 The cache by default continues downloading aborted requests
5974 which are almost completed (less than 16 KB remaining). This
5975 may be undesirable on slow (e.g. SLIP) links and/or very busy
5976 caches. Impatient users may tie up file descriptors and
5977 bandwidth by repeatedly requesting and immediately aborting
5980 When the user aborts a request, Squid will check the
5981 quick_abort values to the amount of data transferred until
5984 If the transfer has less than 'quick_abort_min' KB remaining,
5985 it will finish the retrieval.
5987 If the transfer has more than 'quick_abort_max' KB remaining,
5988 it will abort the retrieval.
5990 If more than 'quick_abort_pct' of the transfer has completed,
5991 it will finish the retrieval.
5993 If you do not want any retrieval to continue after the client
5994 has aborted, set both 'quick_abort_min' and 'quick_abort_max'
5997 If you want retrievals to always continue if they are being
5998 cached set 'quick_abort_min' to '-1 KB'.
6001 NAME: read_ahead_gap
6002 COMMENT: buffer-size
6004 LOC: Config.readAheadGap
6007 The amount of data the cache will buffer ahead of what has been
6008 sent to the client when retrieving an object from another server.
6012 IFDEF: USE_HTTP_VIOLATIONS
6015 LOC: Config.negativeTtl
6018 Set the Default Time-to-Live (TTL) for failed requests.
6019 Certain types of failures (such as "connection refused" and
6020 "404 Not Found") are able to be negatively-cached for a short time.
6021 Modern web servers should provide Expires: header, however if they
6022 do not this can provide a minimum TTL.
6023 The default is not to cache errors with unknown expiry details.
6025 Note that this is different from negative caching of DNS lookups.
6027 WARNING: Doing this VIOLATES the HTTP standard. Enabling
6028 this feature could make you liable for problems which it
6032 NAME: positive_dns_ttl
6035 LOC: Config.positiveDnsTtl
6038 Upper limit on how long Squid will cache positive DNS responses.
6039 Default is 6 hours (360 minutes). This directive must be set
6040 larger than negative_dns_ttl.
6043 NAME: negative_dns_ttl
6046 LOC: Config.negativeDnsTtl
6049 Time-to-Live (TTL) for negative caching of failed DNS lookups.
6050 This also sets the lower cache limit on positive lookups.
6051 Minimum value is 1 second, and it is not recommendable to go
6052 much below 10 seconds.
6055 NAME: range_offset_limit
6056 COMMENT: size [acl acl...]
6058 LOC: Config.rangeOffsetLimit
6061 usage: (size) [units] [[!]aclname]
6063 Sets an upper limit on how far (number of bytes) into the file
6064 a Range request may be to cause Squid to prefetch the whole file.
6065 If beyond this limit, Squid forwards the Range request as it is and
6066 the result is NOT cached.
6068 This is to stop a far ahead range request (lets say start at 17MB)
6069 from making Squid fetch the whole object up to that point before
6070 sending anything to the client.
6072 Multiple range_offset_limit lines may be specified, and they will
6073 be searched from top to bottom on each request until a match is found.
6074 The first match found will be used. If no line matches a request, the
6075 default limit of 0 bytes will be used.
6077 'size' is the limit specified as a number of units.
6079 'units' specifies whether to use bytes, KB, MB, etc.
6080 If no units are specified bytes are assumed.
6082 A size of 0 causes Squid to never fetch more than the
6083 client requested. (default)
6085 A size of 'none' causes Squid to always fetch the object from the
6086 beginning so it may cache the result. (2.0 style)
6088 'aclname' is the name of a defined ACL.
6090 NP: Using 'none' as the byte value here will override any quick_abort settings
6091 that may otherwise apply to the range request. The range request will
6092 be fully fetched from start to finish regardless of the client
6093 actions. This affects bandwidth usage.
6096 NAME: minimum_expiry_time
6099 LOC: Config.minimum_expiry_time
6102 The minimum caching time according to (Expires - Date)
6103 headers Squid honors if the object can't be revalidated.
6104 The default is 60 seconds.
6106 In reverse proxy environments it might be desirable to honor
6107 shorter object lifetimes. It is most likely better to make
6108 your server return a meaningful Last-Modified header however.
6110 In ESI environments where page fragments often have short
6111 lifetimes, this will often be best set to 0.
6114 NAME: store_avg_object_size
6118 LOC: Config.Store.avgObjectSize
6120 Average object size, used to estimate number of objects your
6121 cache can hold. The default is 13 KB.
6123 This is used to pre-seed the cache index memory allocation to
6124 reduce expensive reallocate operations while handling clients
6125 traffic. Too-large values may result in memory allocation during
6126 peak traffic, too-small values will result in wasted memory.
6128 Check the cache manager 'info' report metrics for the real
6129 object sizes seen by your Squid before tuning this.
6132 NAME: store_objects_per_bucket
6135 LOC: Config.Store.objectsPerBucket
6137 Target number of objects per bucket in the store hash table.
6138 Lowering this value increases the total number of buckets and
6139 also the storage maintenance rate. The default is 20.
6144 -----------------------------------------------------------------------------
6147 NAME: request_header_max_size
6151 LOC: Config.maxRequestHeaderSize
6153 This specifies the maximum size for HTTP headers in a request.
6154 Request headers are usually relatively small (about 512 bytes).
6155 Placing a limit on the request header size will catch certain
6156 bugs (for example with persistent connections) and possibly
6157 buffer-overflow or denial-of-service attacks.
6160 NAME: reply_header_max_size
6164 LOC: Config.maxReplyHeaderSize
6166 This specifies the maximum size for HTTP headers in a reply.
6167 Reply headers are usually relatively small (about 512 bytes).
6168 Placing a limit on the reply header size will catch certain
6169 bugs (for example with persistent connections) and possibly
6170 buffer-overflow or denial-of-service attacks.
6173 NAME: request_body_max_size
6177 DEFAULT_DOC: No limit.
6178 LOC: Config.maxRequestBodySize
6180 This specifies the maximum size for an HTTP request body.
6181 In other words, the maximum size of a PUT/POST request.
6182 A user who attempts to send a request with a body larger
6183 than this limit receives an "Invalid Request" error message.
6184 If you set this parameter to a zero (the default), there will
6185 be no limit imposed.
6187 See also client_request_buffer_max_size for an alternative
6188 limitation on client uploads which can be configured.
6191 NAME: client_request_buffer_max_size
6195 LOC: Config.maxRequestBufferSize
6197 This specifies the maximum buffer size of a client request.
6198 It prevents squid eating too much memory when somebody uploads
6203 IFDEF: USE_HTTP_VIOLATIONS
6206 DEFAULT_DOC: Obey RFC 2616.
6207 LOC: Config.accessList.brokenPosts
6209 A list of ACL elements which, if matched, causes Squid to send
6210 an extra CRLF pair after the body of a PUT/POST request.
6212 Some HTTP servers has broken implementations of PUT/POST,
6213 and rely on an extra CRLF pair sent by some WWW clients.
6215 Quote from RFC2616 section 4.1 on this matter:
6217 Note: certain buggy HTTP/1.0 client implementations generate an
6218 extra CRLF's after a POST request. To restate what is explicitly
6219 forbidden by the BNF, an HTTP/1.1 client must not preface or follow
6220 a request with an extra CRLF.
6222 This clause only supports fast acl types.
6223 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6226 acl buggy_server url_regex ^http://....
6227 broken_posts allow buggy_server
6230 NAME: adaptation_uses_indirect_client icap_uses_indirect_client
6233 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_ADAPTATION
6235 LOC: Adaptation::Config::use_indirect_client
6237 Controls whether the indirect client IP address (instead of the direct
6238 client IP address) is passed to adaptation services.
6240 See also: follow_x_forwarded_for adaptation_send_client_ip
6244 IFDEF: USE_HTTP_VIOLATIONS
6248 LOC: Config.onoff.via
6250 If set (default), Squid will include a Via header in requests and
6251 replies as required by RFC2616.
6254 NAME: vary_ignore_expire
6257 LOC: Config.onoff.vary_ignore_expire
6260 Many HTTP servers supporting Vary gives such objects
6261 immediate expiry time with no cache-control header
6262 when requested by a HTTP/1.0 client. This option
6263 enables Squid to ignore such expiry times until
6264 HTTP/1.1 is fully implemented.
6266 WARNING: If turned on this may eventually cause some
6267 varying objects not intended for caching to get cached.
6270 NAME: request_entities
6272 LOC: Config.onoff.request_entities
6275 Squid defaults to deny GET and HEAD requests with request entities,
6276 as the meaning of such requests are undefined in the HTTP standard
6277 even if not explicitly forbidden.
6279 Set this directive to on if you have clients which insists
6280 on sending request entities in GET or HEAD requests. But be warned
6281 that there is server software (both proxies and web servers) which
6282 can fail to properly process this kind of request which may make you
6283 vulnerable to cache pollution attacks if enabled.
6286 NAME: request_header_access
6287 IFDEF: USE_HTTP_VIOLATIONS
6288 TYPE: http_header_access
6289 LOC: Config.request_header_access
6291 DEFAULT_DOC: No limits.
6293 Usage: request_header_access header_name allow|deny [!]aclname ...
6295 WARNING: Doing this VIOLATES the HTTP standard. Enabling
6296 this feature could make you liable for problems which it
6299 This option replaces the old 'anonymize_headers' and the
6300 older 'http_anonymizer' option with something that is much
6301 more configurable. A list of ACLs for each header name allows
6302 removal of specific header fields under specific conditions.
6304 This option only applies to outgoing HTTP request headers (i.e.,
6305 headers sent by Squid to the next HTTP hop such as a cache peer
6306 or an origin server). The option has no effect during cache hit
6307 detection. The equivalent adaptation vectoring point in ICAP
6308 terminology is post-cache REQMOD.
6310 The option is applied to individual outgoing request header
6311 fields. For each request header field F, Squid uses the first
6312 qualifying sets of request_header_access rules:
6314 1. Rules with header_name equal to F's name.
6315 2. Rules with header_name 'Other', provided F's name is not
6316 on the hard-coded list of commonly used HTTP header names.
6317 3. Rules with header_name 'All'.
6319 Within that qualifying rule set, rule ACLs are checked as usual.
6320 If ACLs of an "allow" rule match, the header field is allowed to
6321 go through as is. If ACLs of a "deny" rule match, the header is
6322 removed and request_header_replace is then checked to identify
6323 if the removed header has a replacement. If no rules within the
6324 set have matching ACLs, the header field is left as is.
6326 For example, to achieve the same behavior as the old
6327 'http_anonymizer standard' option, you should use:
6329 request_header_access From deny all
6330 request_header_access Referer deny all
6331 request_header_access User-Agent deny all
6333 Or, to reproduce the old 'http_anonymizer paranoid' feature
6336 request_header_access Authorization allow all
6337 request_header_access Proxy-Authorization allow all
6338 request_header_access Cache-Control allow all
6339 request_header_access Content-Length allow all
6340 request_header_access Content-Type allow all
6341 request_header_access Date allow all
6342 request_header_access Host allow all
6343 request_header_access If-Modified-Since allow all
6344 request_header_access Pragma allow all
6345 request_header_access Accept allow all
6346 request_header_access Accept-Charset allow all
6347 request_header_access Accept-Encoding allow all
6348 request_header_access Accept-Language allow all
6349 request_header_access Connection allow all
6350 request_header_access All deny all
6352 HTTP reply headers are controlled with the reply_header_access directive.
6354 By default, all headers are allowed (no anonymizing is performed).
6357 NAME: reply_header_access
6358 IFDEF: USE_HTTP_VIOLATIONS
6359 TYPE: http_header_access
6360 LOC: Config.reply_header_access
6362 DEFAULT_DOC: No limits.
6364 Usage: reply_header_access header_name allow|deny [!]aclname ...
6366 WARNING: Doing this VIOLATES the HTTP standard. Enabling
6367 this feature could make you liable for problems which it
6370 This option only applies to reply headers, i.e., from the
6371 server to the client.
6373 This is the same as request_header_access, but in the other
6374 direction. Please see request_header_access for detailed
6377 For example, to achieve the same behavior as the old
6378 'http_anonymizer standard' option, you should use:
6380 reply_header_access Server deny all
6381 reply_header_access WWW-Authenticate deny all
6382 reply_header_access Link deny all
6384 Or, to reproduce the old 'http_anonymizer paranoid' feature
6387 reply_header_access Allow allow all
6388 reply_header_access WWW-Authenticate allow all
6389 reply_header_access Proxy-Authenticate allow all
6390 reply_header_access Cache-Control allow all
6391 reply_header_access Content-Encoding allow all
6392 reply_header_access Content-Length allow all
6393 reply_header_access Content-Type allow all
6394 reply_header_access Date allow all
6395 reply_header_access Expires allow all
6396 reply_header_access Last-Modified allow all
6397 reply_header_access Location allow all
6398 reply_header_access Pragma allow all
6399 reply_header_access Content-Language allow all
6400 reply_header_access Retry-After allow all
6401 reply_header_access Title allow all
6402 reply_header_access Content-Disposition allow all
6403 reply_header_access Connection allow all
6404 reply_header_access All deny all
6406 HTTP request headers are controlled with the request_header_access directive.
6408 By default, all headers are allowed (no anonymizing is
6412 NAME: request_header_replace header_replace
6413 IFDEF: USE_HTTP_VIOLATIONS
6414 TYPE: http_header_replace
6415 LOC: Config.request_header_access
6418 Usage: request_header_replace header_name message
6419 Example: request_header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
6421 This option allows you to change the contents of headers
6422 denied with request_header_access above, by replacing them
6423 with some fixed string.
6425 This only applies to request headers, not reply headers.
6427 By default, headers are removed if denied.
6430 NAME: reply_header_replace
6431 IFDEF: USE_HTTP_VIOLATIONS
6432 TYPE: http_header_replace
6433 LOC: Config.reply_header_access
6436 Usage: reply_header_replace header_name message
6437 Example: reply_header_replace Server Foo/1.0
6439 This option allows you to change the contents of headers
6440 denied with reply_header_access above, by replacing them
6441 with some fixed string.
6443 This only applies to reply headers, not request headers.
6445 By default, headers are removed if denied.
6448 NAME: request_header_add
6449 TYPE: HeaderWithAclList
6450 LOC: Config.request_header_add
6453 Usage: request_header_add field-name field-value [ acl ... ]
6454 Example: request_header_add X-Client-CA "CA=%ssl::>cert_issuer" all
6456 This option adds header fields to outgoing HTTP requests (i.e.,
6457 request headers sent by Squid to the next HTTP hop such as a
6458 cache peer or an origin server). The option has no effect during
6459 cache hit detection. The equivalent adaptation vectoring point
6460 in ICAP terminology is post-cache REQMOD.
6462 Field-name is a token specifying an HTTP header name. If a
6463 standard HTTP header name is used, Squid does not check whether
6464 the new header conflicts with any existing headers or violates
6465 HTTP rules. If the request to be modified already contains a
6466 field with the same name, the old field is preserved but the
6467 header field values are not merged.
6469 Field-value is either a token or a quoted string. If quoted
6470 string format is used, then the surrounding quotes are removed
6471 while escape sequences and %macros are processed.
6473 One or more Squid ACLs may be specified to restrict header
6474 injection to matching requests. As always in squid.conf, all
6475 ACLs in the ACL list must be satisfied for the insertion to
6476 happen. The request_header_add supports fast ACLs only.
6478 See also: reply_header_add.
6481 NAME: reply_header_add
6482 TYPE: HeaderWithAclList
6483 LOC: Config.reply_header_add
6486 Usage: reply_header_add field-name field-value [ acl ... ]
6487 Example: reply_header_add X-Client-CA "CA=%ssl::>cert_issuer" all
6489 This option adds header fields to outgoing HTTP responses (i.e., response
6490 headers delivered by Squid to the client). This option has no effect on
6491 cache hit detection. The equivalent adaptation vectoring point in
6492 ICAP terminology is post-cache RESPMOD. This option does not apply to
6493 successful CONNECT replies.
6495 Field-name is a token specifying an HTTP header name. If a
6496 standard HTTP header name is used, Squid does not check whether
6497 the new header conflicts with any existing headers or violates
6498 HTTP rules. If the response to be modified already contains a
6499 field with the same name, the old field is preserved but the
6500 header field values are not merged.
6502 Field-value is either a token or a quoted string. If quoted
6503 string format is used, then the surrounding quotes are removed
6504 while escape sequences and %macros are processed.
6506 One or more Squid ACLs may be specified to restrict header
6507 injection to matching responses. As always in squid.conf, all
6508 ACLs in the ACL list must be satisfied for the insertion to
6509 happen. The reply_header_add option supports fast ACLs only.
6511 See also: request_header_add.
6519 This option used to log custom information about the master
6520 transaction. For example, an admin may configure Squid to log
6521 which "user group" the transaction belongs to, where "user group"
6522 will be determined based on a set of ACLs and not [just]
6523 authentication information.
6524 Values of key/value pairs can be logged using %{key}note macros:
6526 note key value acl ...
6527 logformat myFormat ... %{key}note ...
6530 NAME: relaxed_header_parser
6531 COMMENT: on|off|warn
6533 LOC: Config.onoff.relaxed_header_parser
6536 In the default "on" setting Squid accepts certain forms
6537 of non-compliant HTTP messages where it is unambiguous
6538 what the sending application intended even if the message
6539 is not correctly formatted. The messages is then normalized
6540 to the correct form when forwarded by Squid.
6542 If set to "warn" then a warning will be emitted in cache.log
6543 each time such HTTP error is encountered.
6545 If set to "off" then such HTTP errors will cause the request
6546 or response to be rejected.
6549 NAME: collapsed_forwarding
6552 LOC: Config.onoff.collapsed_forwarding
6555 This option controls whether Squid is allowed to merge multiple
6556 potentially cachable requests for the same URI before Squid knows
6557 whether the response is going to be cachable.
6559 When enabled, instead of forwarding each concurrent request for
6560 the same URL, Squid just sends the first of them. The other, so
6561 called "collapsed" requests, wait for the response to the first
6562 request and, if it happens to be cachable, use that response.
6563 Here, "concurrent requests" means "received after the first
6564 request headers were parsed and before the corresponding response
6565 headers were parsed".
6567 This feature is disabled by default: enabling collapsed
6568 forwarding needlessly delays forwarding requests that look
6569 cachable (when they are collapsed) but then need to be forwarded
6570 individually anyway because they end up being for uncachable
6571 content. However, in some cases, such as acceleration of highly
6572 cachable content with periodic or grouped expiration times, the
6573 gains from collapsing [large volumes of simultaneous refresh
6574 requests] outweigh losses from such delays.
6576 Squid collapses two kinds of requests: regular client requests
6577 received on one of the listening ports and internal "cache
6578 revalidation" requests which are triggered by those regular
6579 requests hitting a stale cached object. Revalidation collapsing
6580 is currently disabled for Squid instances containing SMP-aware
6581 disk or memory caches and for Vary-controlled cached objects.
6584 NAME: collapsed_forwarding_shared_entries_limit
6585 COMMENT: (number of entries)
6587 LOC: Config.collapsed_forwarding_shared_entries_limit
6590 This limits the size of a table used for sharing information
6591 about collapsible entries among SMP workers. Limiting sharing
6592 too much results in cache content duplication and missed
6593 collapsing opportunities. Using excessively large values
6594 wastes shared memory.
6596 The limit should be significantly larger then the number of
6597 concurrent collapsible entries one wants to share. For a cache
6598 that handles less than 5000 concurrent requests, the default
6599 setting of 16384 should be plenty.
6601 If the limit is set to zero, it disables sharing of collapsed
6602 forwarding between SMP workers.
6607 -----------------------------------------------------------------------------
6610 NAME: forward_timeout
6613 LOC: Config.Timeout.forward
6616 This parameter specifies how long Squid should at most attempt in
6617 finding a forwarding path for the request before giving up.
6620 NAME: connect_timeout
6623 LOC: Config.Timeout.connect
6626 This parameter specifies how long to wait for the TCP connect to
6627 the requested server or peer to complete before Squid should
6628 attempt to find another path where to forward the request.
6631 NAME: peer_connect_timeout
6634 LOC: Config.Timeout.peer_connect
6637 This parameter specifies how long to wait for a pending TCP
6638 connection to a peer cache. The default is 30 seconds. You
6639 may also set different timeout values for individual neighbors
6640 with the 'connect-timeout' option on a 'cache_peer' line.
6646 LOC: Config.Timeout.read
6649 Applied on peer server connections.
6651 After each successful read(), the timeout will be extended by this
6652 amount. If no data is read again after this amount of time,
6653 the request is aborted and logged with ERR_READ_TIMEOUT.
6655 The default is 15 minutes.
6661 LOC: Config.Timeout.write
6664 This timeout is tracked for all connections that have data
6665 available for writing and are waiting for the socket to become
6666 ready. After each successful write, the timeout is extended by
6667 the configured amount. If Squid has data to write but the
6668 connection is not ready for the configured duration, the
6669 transaction associated with the connection is terminated. The
6670 default is 15 minutes.
6673 NAME: request_timeout
6675 LOC: Config.Timeout.request
6678 How long to wait for complete HTTP request headers after initial
6679 connection establishment.
6682 NAME: request_start_timeout
6684 LOC: Config.Timeout.request_start_timeout
6687 How long to wait for the first request byte after initial
6688 connection establishment.
6691 NAME: client_idle_pconn_timeout persistent_request_timeout
6693 LOC: Config.Timeout.clientIdlePconn
6696 How long to wait for the next HTTP request on a persistent
6697 client connection after the previous request completes.
6700 NAME: ftp_client_idle_timeout
6702 LOC: Config.Timeout.ftpClientIdle
6705 How long to wait for an FTP request on a connection to Squid ftp_port.
6706 Many FTP clients do not deal with idle connection closures well,
6707 necessitating a longer default timeout than client_idle_pconn_timeout
6708 used for incoming HTTP requests.
6711 NAME: client_lifetime
6714 LOC: Config.Timeout.lifetime
6717 The maximum amount of time a client (browser) is allowed to
6718 remain connected to the cache process. This protects the Cache
6719 from having a lot of sockets (and hence file descriptors) tied up
6720 in a CLOSE_WAIT state from remote clients that go away without
6721 properly shutting down (either because of a network failure or
6722 because of a poor client implementation). The default is one
6725 NOTE: The default value is intended to be much larger than any
6726 client would ever need to be connected to your cache. You
6727 should probably change client_lifetime only as a last resort.
6728 If you seem to have many client connections tying up
6729 filedescriptors, we recommend first tuning the read_timeout,
6730 request_timeout, persistent_request_timeout and quick_abort values.
6733 NAME: pconn_lifetime
6736 LOC: Config.Timeout.pconnLifetime
6739 Desired maximum lifetime of a persistent connection.
6740 When set, Squid will close a now-idle persistent connection that
6741 exceeded configured lifetime instead of moving the connection into
6742 the idle connection pool (or equivalent). No effect on ongoing/active
6743 transactions. Connection lifetime is the time period from the
6744 connection acceptance or opening time until "now".
6746 This limit is useful in environments with long-lived connections
6747 where Squid configuration or environmental factors change during a
6748 single connection lifetime. If unrestricted, some connections may
6749 last for hours and even days, ignoring those changes that should
6750 have affected their behavior or their existence.
6752 Currently, a new lifetime value supplied via Squid reconfiguration
6753 has no effect on already idle connections unless they become busy.
6755 When set to '0' this limit is not used.
6758 NAME: half_closed_clients
6760 LOC: Config.onoff.half_closed_clients
6763 Some clients may shutdown the sending side of their TCP
6764 connections, while leaving their receiving sides open. Sometimes,
6765 Squid can not tell the difference between a half-closed and a
6766 fully-closed TCP connection.
6768 By default, Squid will immediately close client connections when
6769 read(2) returns "no more data to read."
6771 Change this option to 'on' and Squid will keep open connections
6772 until a read(2) or write(2) on the socket returns an error.
6773 This may show some benefits for reverse proxies. But if not
6774 it is recommended to leave OFF.
6777 NAME: server_idle_pconn_timeout pconn_timeout
6779 LOC: Config.Timeout.serverIdlePconn
6782 Timeout for idle persistent connections to servers and other
6789 LOC: Ident::TheConfig.timeout
6792 Maximum time to wait for IDENT lookups to complete.
6794 If this is too high, and you enabled IDENT lookups from untrusted
6795 users, you might be susceptible to denial-of-service by having
6796 many ident requests going at once.
6799 NAME: shutdown_lifetime
6802 LOC: Config.shutdownLifetime
6805 When SIGTERM or SIGHUP is received, the cache is put into
6806 "shutdown pending" mode until all active sockets are closed.
6807 This value is the lifetime to set for all open descriptors
6808 during shutdown mode. Any active clients after this many
6809 seconds will receive a 'timeout' message.
6813 ADMINISTRATIVE PARAMETERS
6814 -----------------------------------------------------------------------------
6820 LOC: Config.adminEmail
6822 Email-address of local cache manager who will receive
6823 mail if the cache dies. The default is "webmaster".
6829 LOC: Config.EmailFrom
6831 From: email-address for mail sent when the cache dies.
6832 The default is to use 'squid@unique_hostname'.
6834 See also: unique_hostname directive.
6840 LOC: Config.EmailProgram
6842 Email program used to send mail if the cache dies.
6843 The default is "mail". The specified program must comply
6844 with the standard Unix mail syntax:
6845 mail-program recipient < mailfile
6847 Optional command line options can be specified.
6850 NAME: cache_effective_user
6852 DEFAULT: @DEFAULT_CACHE_EFFECTIVE_USER@
6853 LOC: Config.effectiveUser
6855 If you start Squid as root, it will change its effective/real
6856 UID/GID to the user specified below. The default is to change
6857 to UID of @DEFAULT_CACHE_EFFECTIVE_USER@.
6858 see also; cache_effective_group
6861 NAME: cache_effective_group
6864 DEFAULT_DOC: Use system group memberships of the cache_effective_user account
6865 LOC: Config.effectiveGroup
6867 Squid sets the GID to the effective user's default group ID
6868 (taken from the password file) and supplementary group list
6869 from the groups membership.
6871 If you want Squid to run with a specific GID regardless of
6872 the group memberships of the effective user then set this
6873 to the group (or GID) you want Squid to run as. When set
6874 all other group privileges of the effective user are ignored
6875 and only this GID is effective. If Squid is not started as
6876 root the user starting Squid MUST be member of the specified
6879 This option is not recommended by the Squid Team.
6880 Our preference is for administrators to configure a secure
6881 user account for squid with UID/GID matching system policies.
6884 NAME: httpd_suppress_version_string
6888 LOC: Config.onoff.httpd_suppress_version_string
6890 Suppress Squid version string info in HTTP headers and HTML error pages.
6893 NAME: visible_hostname
6895 LOC: Config.visibleHostname
6897 DEFAULT_DOC: Automatically detect the system host name
6899 If you want to present a special hostname in error messages, etc,
6900 define this. Otherwise, the return value of gethostname()
6901 will be used. If you have multiple caches in a cluster and
6902 get errors about IP-forwarding you must set them to have individual
6903 names with this setting.
6906 NAME: unique_hostname
6908 LOC: Config.uniqueHostname
6910 DEFAULT_DOC: Copy the value from visible_hostname
6912 If you want to have multiple machines with the same
6913 'visible_hostname' you must give each machine a different
6914 'unique_hostname' so forwarding loops can be detected.
6917 NAME: hostname_aliases
6919 LOC: Config.hostnameAliases
6922 A list of other DNS names your cache has.
6930 Minimum umask which should be enforced while the proxy
6931 is running, in addition to the umask set at startup.
6933 For a traditional octal representation of umasks, start
6938 OPTIONS FOR THE CACHE REGISTRATION SERVICE
6939 -----------------------------------------------------------------------------
6941 This section contains parameters for the (optional) cache
6942 announcement service. This service is provided to help
6943 cache administrators locate one another in order to join or
6944 create cache hierarchies.
6946 An 'announcement' message is sent (via UDP) to the registration
6947 service by Squid. By default, the announcement message is NOT
6948 SENT unless you enable it with 'announce_period' below.
6950 The announcement message includes your hostname, plus the
6951 following information from this configuration file:
6957 All current information is processed regularly and made
6958 available on the Web at http://www.ircache.net/Cache/Tracker/.
6961 NAME: announce_period
6963 LOC: Config.Announce.period
6965 DEFAULT_DOC: Announcement messages disabled.
6967 This is how frequently to send cache announcements.
6969 To enable announcing your cache, just set an announce period.
6972 announce_period 1 day
6977 DEFAULT: tracker.ircache.net
6978 LOC: Config.Announce.host
6980 Set the hostname where announce registration messages will be sent.
6982 See also announce_port and announce_file
6988 LOC: Config.Announce.file
6990 The contents of this file will be included in the announce
6991 registration messages.
6997 LOC: Config.Announce.port
6999 Set the port where announce registration messages will be sent.
7001 See also announce_host and announce_file
7005 HTTPD-ACCELERATOR OPTIONS
7006 -----------------------------------------------------------------------------
7009 NAME: httpd_accel_surrogate_id
7012 DEFAULT_DOC: visible_hostname is used if no specific ID is set.
7013 LOC: Config.Accel.surrogate_id
7015 Surrogates (http://www.esi.org/architecture_spec_1.0.html)
7016 need an identification token to allow control targeting. Because
7017 a farm of surrogates may all perform the same tasks, they may share
7018 an identification token.
7021 NAME: http_accel_surrogate_remote
7025 LOC: Config.onoff.surrogate_is_remote
7027 Remote surrogates (such as those in a CDN) honour the header
7028 "Surrogate-Control: no-store-remote".
7030 Set this to on to have squid behave as a remote surrogate.
7034 IFDEF: USE_SQUID_ESI
7035 COMMENT: libxml2|expat
7037 LOC: ESIParser::Type
7039 DEFAULT_DOC: Selects libxml2 if available at ./configure time or libexpat otherwise.
7041 Selects the XML parsing library to use when interpreting responses with
7044 To disable ESI handling completely, ./configure Squid with --disable-esi.
7048 DELAY POOL PARAMETERS
7049 -----------------------------------------------------------------------------
7053 TYPE: delay_pool_count
7055 IFDEF: USE_DELAY_POOLS
7058 This represents the number of delay pools to be used. For example,
7059 if you have one class 2 delay pool and one class 3 delays pool, you
7060 have a total of 2 delay pools.
7062 See also delay_parameters, delay_class, delay_access for pool
7063 configuration details.
7067 TYPE: delay_pool_class
7069 IFDEF: USE_DELAY_POOLS
7072 This defines the class of each delay pool. There must be exactly one
7073 delay_class line for each delay pool. For example, to define two
7074 delay pools, one of class 2 and one of class 3, the settings above
7078 delay_pools 4 # 4 delay pools
7079 delay_class 1 2 # pool 1 is a class 2 pool
7080 delay_class 2 3 # pool 2 is a class 3 pool
7081 delay_class 3 4 # pool 3 is a class 4 pool
7082 delay_class 4 5 # pool 4 is a class 5 pool
7084 The delay pool classes are:
7086 class 1 Everything is limited by a single aggregate
7089 class 2 Everything is limited by a single aggregate
7090 bucket as well as an "individual" bucket chosen
7091 from bits 25 through 32 of the IPv4 address.
7093 class 3 Everything is limited by a single aggregate
7094 bucket as well as a "network" bucket chosen
7095 from bits 17 through 24 of the IP address and a
7096 "individual" bucket chosen from bits 17 through
7097 32 of the IPv4 address.
7099 class 4 Everything in a class 3 delay pool, with an
7100 additional limit on a per user basis. This
7101 only takes effect if the username is established
7102 in advance - by forcing authentication in your
7105 class 5 Requests are grouped according their tag (see
7106 external_acl's tag= reply).
7109 Each pool also requires a delay_parameters directive to configure the pool size
7110 and speed limits used whenever the pool is applied to a request. Along with
7111 a set of delay_access directives to determine when it is used.
7113 NOTE: If an IP address is a.b.c.d
7114 -> bits 25 through 32 are "d"
7115 -> bits 17 through 24 are "c"
7116 -> bits 17 through 32 are "c * 256 + d"
7118 NOTE-2: Due to the use of bitmasks in class 2,3,4 pools they only apply to
7119 IPv4 traffic. Class 1 and 5 pools may be used with IPv6 traffic.
7121 This clause only supports fast acl types.
7122 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7124 See also delay_parameters and delay_access.
7128 TYPE: delay_pool_access
7130 DEFAULT_DOC: Deny using the pool, unless allow rules exist in squid.conf for the pool.
7131 IFDEF: USE_DELAY_POOLS
7134 This is used to determine which delay pool a request falls into.
7136 delay_access is sorted per pool and the matching starts with pool 1,
7137 then pool 2, ..., and finally pool N. The first delay pool where the
7138 request is allowed is selected for the request. If it does not allow
7139 the request to any pool then the request is not delayed (default).
7141 For example, if you want some_big_clients in delay
7142 pool 1 and lotsa_little_clients in delay pool 2:
7144 delay_access 1 allow some_big_clients
7145 delay_access 1 deny all
7146 delay_access 2 allow lotsa_little_clients
7147 delay_access 2 deny all
7148 delay_access 3 allow authenticated_clients
7150 See also delay_parameters and delay_class.
7154 NAME: delay_parameters
7155 TYPE: delay_pool_rates
7157 IFDEF: USE_DELAY_POOLS
7160 This defines the parameters for a delay pool. Each delay pool has
7161 a number of "buckets" associated with it, as explained in the
7162 description of delay_class.
7164 For a class 1 delay pool, the syntax is:
7166 delay_parameters pool aggregate
7168 For a class 2 delay pool:
7170 delay_parameters pool aggregate individual
7172 For a class 3 delay pool:
7174 delay_parameters pool aggregate network individual
7176 For a class 4 delay pool:
7178 delay_parameters pool aggregate network individual user
7180 For a class 5 delay pool:
7182 delay_parameters pool tagrate
7184 The option variables are:
7186 pool a pool number - ie, a number between 1 and the
7187 number specified in delay_pools as used in
7190 aggregate the speed limit parameters for the aggregate bucket
7193 individual the speed limit parameters for the individual
7194 buckets (class 2, 3).
7196 network the speed limit parameters for the network buckets
7199 user the speed limit parameters for the user buckets
7202 tagrate the speed limit parameters for the tag buckets
7205 A pair of delay parameters is written restore/maximum, where restore is
7206 the number of bytes (not bits - modem and network speeds are usually
7207 quoted in bits) per second placed into the bucket, and maximum is the
7208 maximum number of bytes which can be in the bucket at any time.
7210 There must be one delay_parameters line for each delay pool.
7213 For example, if delay pool number 1 is a class 2 delay pool as in the
7214 above example, and is being used to strictly limit each host to 64Kbit/sec
7215 (plus overheads), with no overall limit, the line is:
7217 delay_parameters 1 none 8000/8000
7219 Note that 8 x 8K Byte/sec -> 64K bit/sec.
7221 Note that the word 'none' is used to represent no limit.
7224 And, if delay pool number 2 is a class 3 delay pool as in the above
7225 example, and you want to limit it to a total of 256Kbit/sec (strict limit)
7226 with each 8-bit network permitted 64Kbit/sec (strict limit) and each
7227 individual host permitted 4800bit/sec with a bucket maximum size of 64Kbits
7228 to permit a decent web page to be downloaded at a decent speed
7229 (if the network is not being limited due to overuse) but slow down
7230 large downloads more significantly:
7232 delay_parameters 2 32000/32000 8000/8000 600/8000
7234 Note that 8 x 32K Byte/sec -> 256K bit/sec.
7235 8 x 8K Byte/sec -> 64K bit/sec.
7236 8 x 600 Byte/sec -> 4800 bit/sec.
7239 Finally, for a class 4 delay pool as in the example - each user will
7240 be limited to 128Kbits/sec no matter how many workstations they are logged into.:
7242 delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000
7245 See also delay_class and delay_access.
7249 NAME: delay_initial_bucket_level
7250 COMMENT: (percent, 0-100)
7253 IFDEF: USE_DELAY_POOLS
7254 LOC: Config.Delay.initial
7256 The initial bucket percentage is used to determine how much is put
7257 in each bucket when squid starts, is reconfigured, or first notices
7258 a host accessing it (in class 2 and class 3, individual hosts and
7259 networks only have buckets associated with them once they have been
7264 CLIENT DELAY POOL PARAMETERS
7265 -----------------------------------------------------------------------------
7268 NAME: client_delay_pools
7269 TYPE: client_delay_pool_count
7271 IFDEF: USE_DELAY_POOLS
7272 LOC: Config.ClientDelay
7274 This option specifies the number of client delay pools used. It must
7275 preceed other client_delay_* options.
7278 client_delay_pools 2
7280 See also client_delay_parameters and client_delay_access.
7283 NAME: client_delay_initial_bucket_level
7284 COMMENT: (percent, 0-no_limit)
7287 IFDEF: USE_DELAY_POOLS
7288 LOC: Config.ClientDelay.initial
7290 This option determines the initial bucket size as a percentage of
7291 max_bucket_size from client_delay_parameters. Buckets are created
7292 at the time of the "first" connection from the matching IP. Idle
7293 buckets are periodically deleted up.
7295 You can specify more than 100 percent but note that such "oversized"
7296 buckets are not refilled until their size goes down to max_bucket_size
7297 from client_delay_parameters.
7300 client_delay_initial_bucket_level 50
7303 NAME: client_delay_parameters
7304 TYPE: client_delay_pool_rates
7306 IFDEF: USE_DELAY_POOLS
7307 LOC: Config.ClientDelay
7310 This option configures client-side bandwidth limits using the
7313 client_delay_parameters pool speed_limit max_bucket_size
7315 pool is an integer ID used for client_delay_access matching.
7317 speed_limit is bytes added to the bucket per second.
7319 max_bucket_size is the maximum size of a bucket, enforced after any
7320 speed_limit additions.
7322 Please see the delay_parameters option for more information and
7326 client_delay_parameters 1 1024 2048
7327 client_delay_parameters 2 51200 16384
7329 See also client_delay_access.
7333 NAME: client_delay_access
7334 TYPE: client_delay_pool_access
7336 DEFAULT_DOC: Deny use of the pool, unless allow rules exist in squid.conf for the pool.
7337 IFDEF: USE_DELAY_POOLS
7338 LOC: Config.ClientDelay
7340 This option determines the client-side delay pool for the
7343 client_delay_access pool_ID allow|deny acl_name
7345 All client_delay_access options are checked in their pool ID
7346 order, starting with pool 1. The first checked pool with allowed
7347 request is selected for the request. If no ACL matches or there
7348 are no client_delay_access options, the request bandwidth is not
7351 The ACL-selected pool is then used to find the
7352 client_delay_parameters for the request. Client-side pools are
7353 not used to aggregate clients. Clients are always aggregated
7354 based on their source IP addresses (one bucket per source IP).
7356 This clause only supports fast acl types.
7357 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7358 Additionally, only the client TCP connection details are available.
7359 ACLs testing HTTP properties will not work.
7361 Please see delay_access for more examples.
7364 client_delay_access 1 allow low_rate_network
7365 client_delay_access 2 allow vips_network
7368 See also client_delay_parameters and client_delay_pools.
7371 NAME: response_delay_pool
7372 TYPE: response_delay_pool_parameters
7374 IFDEF: USE_DELAY_POOLS
7375 LOC: Config.MessageDelay
7377 This option configures client response bandwidth limits using the
7380 response_delay_pool name [option=value] ...
7382 name the response delay pool name
7386 individual-restore The speed limit of an individual
7387 bucket(bytes/s). To be used in conjunction
7388 with 'individual-maximum'.
7390 individual-maximum The maximum number of bytes which can
7391 be placed into the individual bucket. To be used
7392 in conjunction with 'individual-restore'.
7394 aggregate-restore The speed limit for the aggregate
7395 bucket(bytes/s). To be used in conjunction with
7396 'aggregate-maximum'.
7398 aggregate-maximum The maximum number of bytes which can
7399 be placed into the aggregate bucket. To be used
7400 in conjunction with 'aggregate-restore'.
7402 initial-bucket-level The initial bucket size as a percentage
7403 of individual-maximum.
7405 Individual and(or) aggregate bucket options may not be specified,
7406 meaning no individual and(or) aggregate speed limitation.
7407 See also response_delay_pool_access and delay_parameters for
7408 terminology details.
7411 NAME: response_delay_pool_access
7412 TYPE: response_delay_pool_access
7414 DEFAULT_DOC: Deny use of the pool, unless allow rules exist in squid.conf for the pool.
7415 IFDEF: USE_DELAY_POOLS
7416 LOC: Config.MessageDelay
7418 Determines whether a specific named response delay pool is used
7419 for the transaction. The syntax for this directive is:
7421 response_delay_pool_access pool_name allow|deny acl_name
7423 All response_delay_pool_access options are checked in the order
7424 they appear in this configuration file. The first rule with a
7425 matching ACL wins. If (and only if) an "allow" rule won, Squid
7426 assigns the response to the corresponding named delay pool.
7430 WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS
7431 -----------------------------------------------------------------------------
7436 LOC: Config.Wccp.router
7438 DEFAULT_DOC: WCCP disabled.
7441 Use this option to define your WCCP ``home'' router for
7444 wccp_router supports a single WCCP(v1) router
7446 wccp2_router supports multiple WCCPv2 routers
7448 only one of the two may be used at the same time and defines
7449 which version of WCCP to use.
7453 TYPE: IpAddress_list
7454 LOC: Config.Wccp2.router
7456 DEFAULT_DOC: WCCPv2 disabled.
7459 Use this option to define your WCCP ``home'' router for
7462 wccp_router supports a single WCCP(v1) router
7464 wccp2_router supports multiple WCCPv2 routers
7466 only one of the two may be used at the same time and defines
7467 which version of WCCP to use.
7472 LOC: Config.Wccp.version
7476 This directive is only relevant if you need to set up WCCP(v1)
7477 to some very old and end-of-life Cisco routers. In all other
7478 setups it must be left unset or at the default setting.
7479 It defines an internal version in the WCCP(v1) protocol,
7480 with version 4 being the officially documented protocol.
7482 According to some users, Cisco IOS 11.2 and earlier only
7483 support WCCP version 3. If you're using that or an earlier
7484 version of IOS, you may need to change this value to 3, otherwise
7485 do not specify this parameter.
7488 NAME: wccp2_rebuild_wait
7490 LOC: Config.Wccp2.rebuildwait
7494 If this is enabled Squid will wait for the cache dir rebuild to finish
7495 before sending the first wccp2 HereIAm packet
7498 NAME: wccp2_forwarding_method
7500 LOC: Config.Wccp2.forwarding_method
7504 WCCP2 allows the setting of forwarding methods between the
7505 router/switch and the cache. Valid values are as follows:
7507 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
7508 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
7510 Currently (as of IOS 12.4) cisco routers only support GRE.
7511 Cisco switches only support the L2 redirect assignment method.
7514 NAME: wccp2_return_method
7516 LOC: Config.Wccp2.return_method
7520 WCCP2 allows the setting of return methods between the
7521 router/switch and the cache for packets that the cache
7522 decides not to handle. Valid values are as follows:
7524 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
7525 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
7527 Currently (as of IOS 12.4) cisco routers only support GRE.
7528 Cisco switches only support the L2 redirect assignment.
7530 If the "ip wccp redirect exclude in" command has been
7531 enabled on the cache interface, then it is still safe for
7532 the proxy server to use a l2 redirect method even if this
7533 option is set to GRE.
7536 NAME: wccp2_assignment_method
7538 LOC: Config.Wccp2.assignment_method
7542 WCCP2 allows the setting of methods to assign the WCCP hash
7543 Valid values are as follows:
7545 hash - Hash assignment
7546 mask - Mask assignment
7548 As a general rule, cisco routers support the hash assignment method
7549 and cisco switches support the mask assignment method.
7554 LOC: Config.Wccp2.info
7555 DEFAULT_IF_NONE: standard 0
7556 DEFAULT_DOC: Use the 'web-cache' standard service.
7559 WCCP2 allows for multiple traffic services. There are two
7560 types: "standard" and "dynamic". The standard type defines
7561 one service id - http (id 0). The dynamic service ids can be from
7562 51 to 255 inclusive. In order to use a dynamic service id
7563 one must define the type of traffic to be redirected; this is done
7564 using the wccp2_service_info option.
7566 The "standard" type does not require a wccp2_service_info option,
7567 just specifying the service id will suffice.
7569 MD5 service authentication can be enabled by adding
7570 "password=<password>" to the end of this service declaration.
7574 wccp2_service standard 0 # for the 'web-cache' standard service
7575 wccp2_service dynamic 80 # a dynamic service type which will be
7576 # fleshed out with subsequent options.
7577 wccp2_service standard 0 password=foo
7580 NAME: wccp2_service_info
7581 TYPE: wccp2_service_info
7582 LOC: Config.Wccp2.info
7586 Dynamic WCCPv2 services require further information to define the
7587 traffic you wish to have diverted.
7591 wccp2_service_info <id> protocol=<protocol> flags=<flag>,<flag>..
7592 priority=<priority> ports=<port>,<port>..
7594 The relevant WCCPv2 flags:
7595 + src_ip_hash, dst_ip_hash
7596 + source_port_hash, dst_port_hash
7597 + src_ip_alt_hash, dst_ip_alt_hash
7598 + src_port_alt_hash, dst_port_alt_hash
7601 The port list can be one to eight entries.
7605 wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source
7606 priority=240 ports=80
7608 Note: the service id must have been defined by a previous
7609 'wccp2_service dynamic <id>' entry.
7614 LOC: Config.Wccp2.weight
7618 Each cache server gets assigned a set of the destination
7619 hash proportional to their weight.
7624 LOC: Config.Wccp.address
7626 DEFAULT_DOC: Address selected by the operating system.
7629 Use this option if you require WCCPv2 to use a specific
7632 The default behavior is to not bind to any specific address.
7637 LOC: Config.Wccp2.address
7639 DEFAULT_DOC: Address selected by the operating system.
7642 Use this option if you require WCCP to use a specific
7645 The default behavior is to not bind to any specific address.
7649 PERSISTENT CONNECTION HANDLING
7650 -----------------------------------------------------------------------------
7652 Also see "pconn_timeout" in the TIMEOUTS section
7655 NAME: client_persistent_connections
7657 LOC: Config.onoff.client_pconns
7660 Persistent connection support for clients.
7661 Squid uses persistent connections (when allowed). You can use
7662 this option to disable persistent connections with clients.
7665 NAME: server_persistent_connections
7667 LOC: Config.onoff.server_pconns
7670 Persistent connection support for servers.
7671 Squid uses persistent connections (when allowed). You can use
7672 this option to disable persistent connections with servers.
7675 NAME: persistent_connection_after_error
7677 LOC: Config.onoff.error_pconns
7680 With this directive the use of persistent connections after
7681 HTTP errors can be disabled. Useful if you have clients
7682 who fail to handle errors on persistent connections proper.
7685 NAME: detect_broken_pconn
7687 LOC: Config.onoff.detect_broken_server_pconns
7690 Some servers have been found to incorrectly signal the use
7691 of HTTP/1.0 persistent connections even on replies not
7692 compatible, causing significant delays. This server problem
7693 has mostly been seen on redirects.
7695 By enabling this directive Squid attempts to detect such
7696 broken replies and automatically assume the reply is finished
7697 after 10 seconds timeout.
7701 CACHE DIGEST OPTIONS
7702 -----------------------------------------------------------------------------
7705 NAME: digest_generation
7706 IFDEF: USE_CACHE_DIGESTS
7708 LOC: Config.onoff.digest_generation
7711 This controls whether the server will generate a Cache Digest
7712 of its contents. By default, Cache Digest generation is
7713 enabled if Squid is compiled with --enable-cache-digests defined.
7716 NAME: digest_bits_per_entry
7717 IFDEF: USE_CACHE_DIGESTS
7719 LOC: Config.digest.bits_per_entry
7722 This is the number of bits of the server's Cache Digest which
7723 will be associated with the Digest entry for a given HTTP
7724 Method and URL (public key) combination. The default is 5.
7727 NAME: digest_rebuild_period
7728 IFDEF: USE_CACHE_DIGESTS
7731 LOC: Config.digest.rebuild_period
7734 This is the wait time between Cache Digest rebuilds.
7737 NAME: digest_rewrite_period
7739 IFDEF: USE_CACHE_DIGESTS
7741 LOC: Config.digest.rewrite_period
7744 This is the wait time between Cache Digest writes to
7748 NAME: digest_swapout_chunk_size
7751 IFDEF: USE_CACHE_DIGESTS
7752 LOC: Config.digest.swapout_chunk_size
7755 This is the number of bytes of the Cache Digest to write to
7756 disk at a time. It defaults to 4096 bytes (4KB), the Squid
7760 NAME: digest_rebuild_chunk_percentage
7761 COMMENT: (percent, 0-100)
7762 IFDEF: USE_CACHE_DIGESTS
7764 LOC: Config.digest.rebuild_chunk_percentage
7767 This is the percentage of the Cache Digest to be scanned at a
7768 time. By default it is set to 10% of the Cache Digest.
7773 -----------------------------------------------------------------------------
7778 LOC: Config.Port.snmp
7780 DEFAULT_DOC: SNMP disabled.
7783 The port number where Squid listens for SNMP requests. To enable
7784 SNMP support set this to a suitable port number. Port number
7785 3401 is often used for the Squid SNMP agent. By default it's
7786 set to "0" (disabled)
7794 LOC: Config.accessList.snmp
7796 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
7799 Allowing or denying access to the SNMP port.
7801 All access to the agent is denied by default.
7804 snmp_access allow|deny [!]aclname ...
7806 This clause only supports fast acl types.
7807 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7810 snmp_access allow snmppublic localhost
7811 snmp_access deny all
7814 NAME: snmp_incoming_address
7816 LOC: Config.Addrs.snmp_incoming
7818 DEFAULT_DOC: Accept SNMP packets from all machine interfaces.
7821 Just like 'udp_incoming_address', but for the SNMP port.
7823 snmp_incoming_address is used for the SNMP socket receiving
7824 messages from SNMP agents.
7826 The default snmp_incoming_address is to listen on all
7827 available network interfaces.
7830 NAME: snmp_outgoing_address
7832 LOC: Config.Addrs.snmp_outgoing
7834 DEFAULT_DOC: Use snmp_incoming_address or an address selected by the operating system.
7837 Just like 'udp_outgoing_address', but for the SNMP port.
7839 snmp_outgoing_address is used for SNMP packets returned to SNMP
7842 If snmp_outgoing_address is not set it will use the same socket
7843 as snmp_incoming_address. Only change this if you want to have
7844 SNMP replies sent using another address than where this Squid
7845 listens for SNMP queries.
7847 NOTE, snmp_incoming_address and snmp_outgoing_address can not have
7848 the same value since they both use the same port.
7853 -----------------------------------------------------------------------------
7856 NAME: icp_port udp_port
7859 DEFAULT_DOC: ICP disabled.
7860 LOC: Config.Port.icp
7862 The port number where Squid sends and receives ICP queries to
7863 and from neighbor caches. The standard UDP port for ICP is 3130.
7866 icp_port @DEFAULT_ICP_PORT@
7873 DEFAULT_DOC: HTCP disabled.
7874 LOC: Config.Port.htcp
7876 The port number where Squid sends and receives HTCP queries to
7877 and from neighbor caches. To turn it on you want to set it to
7884 NAME: log_icp_queries
7888 LOC: Config.onoff.log_udp
7890 If set, ICP queries are logged to access.log. You may wish
7891 do disable this if your ICP load is VERY high to speed things
7892 up or to simplify log analysis.
7895 NAME: udp_incoming_address
7897 LOC:Config.Addrs.udp_incoming
7899 DEFAULT_DOC: Accept packets from all machine interfaces.
7901 udp_incoming_address is used for UDP packets received from other
7904 The default behavior is to not bind to any specific address.
7906 Only change this if you want to have all UDP queries received on
7907 a specific interface/address.
7909 NOTE: udp_incoming_address is used by the ICP, HTCP, and DNS
7910 modules. Altering it will affect all of them in the same manner.
7912 see also; udp_outgoing_address
7914 NOTE, udp_incoming_address and udp_outgoing_address can not
7915 have the same value since they both use the same port.
7918 NAME: udp_outgoing_address
7920 LOC: Config.Addrs.udp_outgoing
7922 DEFAULT_DOC: Use udp_incoming_address or an address selected by the operating system.
7924 udp_outgoing_address is used for UDP packets sent out to other
7927 The default behavior is to not bind to any specific address.
7929 Instead it will use the same socket as udp_incoming_address.
7930 Only change this if you want to have UDP queries sent using another
7931 address than where this Squid listens for UDP queries from other
7934 NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS
7935 modules. Altering it will affect all of them in the same manner.
7937 see also; udp_incoming_address
7939 NOTE, udp_incoming_address and udp_outgoing_address can not
7940 have the same value since they both use the same port.
7947 LOC: Config.onoff.icp_hit_stale
7949 If you want to return ICP_HIT for stale cache objects, set this
7950 option to 'on'. If you have sibling relationships with caches
7951 in other administrative domains, this should be 'off'. If you only
7952 have sibling relationships with caches under your control,
7953 it is probably okay to set this to 'on'.
7954 If set to 'on', your siblings should use the option "allow-miss"
7955 on their cache_peer lines for connecting to you.
7958 NAME: minimum_direct_hops
7961 LOC: Config.minDirectHops
7963 If using the ICMP pinging stuff, do direct fetches for sites
7964 which are no more than this many hops away.
7967 NAME: minimum_direct_rtt
7971 LOC: Config.minDirectRtt
7973 If using the ICMP pinging stuff, do direct fetches for sites
7974 which are no more than this many rtt milliseconds away.
7980 LOC: Config.Netdb.low
7982 The low water mark for the ICMP measurement database.
7984 Note: high watermark controlled by netdb_high directive.
7986 These watermarks are counts, not percents. The defaults are
7987 (low) 900 and (high) 1000. When the high water mark is
7988 reached, database entries will be deleted until the low
7995 LOC: Config.Netdb.high
7997 The high water mark for the ICMP measurement database.
7999 Note: low watermark controlled by netdb_low directive.
8001 These watermarks are counts, not percents. The defaults are
8002 (low) 900 and (high) 1000. When the high water mark is
8003 reached, database entries will be deleted until the low
8007 NAME: netdb_ping_period
8009 LOC: Config.Netdb.period
8012 The minimum period for measuring a site. There will be at
8013 least this much delay between successive pings to the same
8014 network. The default is five minutes.
8021 LOC: Config.onoff.query_icmp
8023 If you want to ask your peers to include ICMP data in their ICP
8024 replies, enable this option.
8026 If your peer has configured Squid (during compilation) with
8027 '--enable-icmp' that peer will send ICMP pings to origin server
8028 sites of the URLs it receives. If you enable this option the
8029 ICP replies from that peer will include the ICMP data (if available).
8030 Then, when choosing a parent cache, Squid will choose the parent with
8031 the minimal RTT to the origin server. When this happens, the
8032 hierarchy field of the access.log will be
8033 "CLOSEST_PARENT_MISS". This option is off by default.
8036 NAME: test_reachability
8040 LOC: Config.onoff.test_reachability
8042 When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
8043 instead of ICP_MISS if the target host is NOT in the ICMP
8044 database, or has a zero RTT.
8047 NAME: icp_query_timeout
8050 DEFAULT_DOC: Dynamic detection.
8052 LOC: Config.Timeout.icp_query
8054 Normally Squid will automatically determine an optimal ICP
8055 query timeout value based on the round-trip-time of recent ICP
8056 queries. If you want to override the value determined by
8057 Squid, set this 'icp_query_timeout' to a non-zero value. This
8058 value is specified in MILLISECONDS, so, to use a 2-second
8059 timeout (the old default), you would write:
8061 icp_query_timeout 2000
8064 NAME: maximum_icp_query_timeout
8068 LOC: Config.Timeout.icp_query_max
8070 Normally the ICP query timeout is determined dynamically. But
8071 sometimes it can lead to very large values (say 5 seconds).
8072 Use this option to put an upper limit on the dynamic timeout
8073 value. Do NOT use this option to always use a fixed (instead
8074 of a dynamic) timeout value. To set a fixed timeout see the
8075 'icp_query_timeout' directive.
8078 NAME: minimum_icp_query_timeout
8082 LOC: Config.Timeout.icp_query_min
8084 Normally the ICP query timeout is determined dynamically. But
8085 sometimes it can lead to very small timeouts, even lower than
8086 the normal latency variance on your link due to traffic.
8087 Use this option to put an lower limit on the dynamic timeout
8088 value. Do NOT use this option to always use a fixed (instead
8089 of a dynamic) timeout value. To set a fixed timeout see the
8090 'icp_query_timeout' directive.
8093 NAME: background_ping_rate
8097 LOC: Config.backgroundPingRate
8099 Controls how often the ICP pings are sent to siblings that
8100 have background-ping set.
8104 MULTICAST ICP OPTIONS
8105 -----------------------------------------------------------------------------
8110 LOC: Config.mcast_group_list
8113 This tag specifies a list of multicast groups which your server
8114 should join to receive multicasted ICP queries.
8116 NOTE! Be very careful what you put here! Be sure you
8117 understand the difference between an ICP _query_ and an ICP
8118 _reply_. This option is to be set only if you want to RECEIVE
8119 multicast queries. Do NOT set this option to SEND multicast
8120 ICP (use cache_peer for that). ICP replies are always sent via
8121 unicast, so this option does not affect whether or not you will
8122 receive replies from multicast group members.
8124 You must be very careful to NOT use a multicast address which
8125 is already in use by another group of caches.
8127 If you are unsure about multicast, please read the Multicast
8128 chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
8130 Usage: mcast_groups 239.128.16.128 224.0.1.20
8132 By default, Squid doesn't listen on any multicast groups.
8135 NAME: mcast_miss_addr
8136 IFDEF: MULTICAST_MISS_STREAM
8138 LOC: Config.mcast_miss.addr
8140 DEFAULT_DOC: disabled.
8142 If you enable this option, every "cache miss" URL will
8143 be sent out on the specified multicast address.
8145 Do not enable this option unless you are are absolutely
8146 certain you understand what you are doing.
8149 NAME: mcast_miss_ttl
8150 IFDEF: MULTICAST_MISS_STREAM
8152 LOC: Config.mcast_miss.ttl
8155 This is the time-to-live value for packets multicasted
8156 when multicasting off cache miss URLs is enabled. By
8157 default this is set to 'site scope', i.e. 16.
8160 NAME: mcast_miss_port
8161 IFDEF: MULTICAST_MISS_STREAM
8163 LOC: Config.mcast_miss.port
8166 This is the port number to be used in conjunction with
8170 NAME: mcast_miss_encode_key
8171 IFDEF: MULTICAST_MISS_STREAM
8173 LOC: Config.mcast_miss.encode_key
8174 DEFAULT: XXXXXXXXXXXXXXXX
8176 The URLs that are sent in the multicast miss stream are
8177 encrypted. This is the encryption key.
8180 NAME: mcast_icp_query_timeout
8184 LOC: Config.Timeout.mcast_icp_query
8186 For multicast peers, Squid regularly sends out ICP "probes" to
8187 count how many other peers are listening on the given multicast
8188 address. This value specifies how long Squid should wait to
8189 count all the replies. The default is 2000 msec, or 2
8194 INTERNAL ICON OPTIONS
8195 -----------------------------------------------------------------------------
8198 NAME: icon_directory
8200 LOC: Config.icons.directory
8201 DEFAULT: @DEFAULT_ICON_DIR@
8203 Where the icons are stored. These are normally kept in
8207 NAME: global_internal_static
8209 LOC: Config.onoff.global_internal_static
8212 This directive controls is Squid should intercept all requests for
8213 /squid-internal-static/ no matter which host the URL is requesting
8214 (default on setting), or if nothing special should be done for
8215 such URLs (off setting). The purpose of this directive is to make
8216 icons etc work better in complex cache hierarchies where it may
8217 not always be possible for all corners in the cache mesh to reach
8218 the server generating a directory listing.
8221 NAME: short_icon_urls
8223 LOC: Config.icons.use_short_names
8226 If this is enabled Squid will use short URLs for icons.
8227 If disabled it will revert to the old behavior of including
8228 it's own name and port in the URL.
8230 If you run a complex cache hierarchy with a mix of Squid and
8231 other proxies you may need to disable this directive.
8236 -----------------------------------------------------------------------------
8239 NAME: error_directory
8241 LOC: Config.errorDirectory
8243 DEFAULT_DOC: Send error pages in the clients preferred language
8245 If you wish to create your own versions of the default
8246 error files to customize them to suit your company copy
8247 the error/template files to another directory and point
8250 WARNING: This option will disable multi-language support
8251 on error pages if used.
8253 The squid developers are interested in making squid available in
8254 a wide variety of languages. If you are making translations for a
8255 language that Squid does not currently provide please consider
8256 contributing your translation back to the project.
8257 http://wiki.squid-cache.org/Translations
8259 The squid developers working on translations are happy to supply drop-in
8260 translated error files in exchange for any new language contributions.
8263 NAME: error_default_language
8264 IFDEF: USE_ERR_LOCALES
8266 LOC: Config.errorDefaultLanguage
8268 DEFAULT_DOC: Generate English language pages.
8270 Set the default language which squid will send error pages in
8271 if no existing translation matches the clients language
8274 If unset (default) generic English will be used.
8276 The squid developers are interested in making squid available in
8277 a wide variety of languages. If you are interested in making
8278 translations for any language see the squid wiki for details.
8279 http://wiki.squid-cache.org/Translations
8282 NAME: error_log_languages
8283 IFDEF: USE_ERR_LOCALES
8285 LOC: Config.errorLogMissingLanguages
8288 Log to cache.log what languages users are attempting to
8289 auto-negotiate for translations.
8291 Successful negotiations are not logged. Only failures
8292 have meaning to indicate that Squid may need an upgrade
8293 of its error page translations.
8296 NAME: err_page_stylesheet
8298 LOC: Config.errorStylesheet
8299 DEFAULT: @DEFAULT_CONFIG_DIR@/errorpage.css
8301 CSS Stylesheet to pattern the display of Squid default error pages.
8303 For information on CSS see http://www.w3.org/Style/CSS/
8308 LOC: Config.errHtmlText
8311 HTML text to include in error messages. Make this a "mailto"
8312 URL to your admin address, or maybe just a link to your
8313 organizations Web page.
8315 To include this in your error messages, you must rewrite
8316 the error template files (found in the "errors" directory).
8317 Wherever you want the 'err_html_text' line to appear,
8318 insert a %L tag in the error template file.
8321 NAME: email_err_data
8324 LOC: Config.onoff.emailErrData
8327 If enabled, information about the occurred error will be
8328 included in the mailto links of the ERR pages (if %W is set)
8329 so that the email body contains the data.
8330 Syntax is <A HREF="mailto:%w%W">%w</A>
8335 LOC: Config.denyInfoList
8338 Usage: deny_info err_page_name acl
8339 or deny_info http://... acl
8340 or deny_info TCP_RESET acl
8342 This can be used to return a ERR_ page for requests which
8343 do not pass the 'http_access' rules. Squid remembers the last
8344 acl it evaluated in http_access, and if a 'deny_info' line exists
8345 for that ACL Squid returns a corresponding error page.
8347 The acl is typically the last acl on the http_access deny line which
8348 denied access. The exceptions to this rule are:
8349 - When Squid needs to request authentication credentials. It's then
8350 the first authentication related acl encountered
8351 - When none of the http_access lines matches. It's then the last
8352 acl processed on the last http_access line.
8353 - When the decision to deny access was made by an adaptation service,
8354 the acl name is the corresponding eCAP or ICAP service_name.
8356 NP: If providing your own custom error pages with error_directory
8357 you may also specify them by your custom file name:
8358 Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
8360 By defaut Squid will send "403 Forbidden". A different 4xx or 5xx
8361 may be specified by prefixing the file name with the code and a colon.
8362 e.g. 404:ERR_CUSTOM_ACCESS_DENIED
8364 Alternatively you can tell Squid to reset the TCP connection
8365 by specifying TCP_RESET.
8367 Or you can specify an error URL or URL pattern. The browsers will
8368 get redirected to the specified URL after formatting tags have
8369 been replaced. Redirect will be done with 302 or 307 according to
8370 HTTP/1.1 specs. A different 3xx code may be specified by prefixing
8371 the URL. e.g. 303:http://example.com/
8374 %a - username (if available. Password NOT included)
8377 %E - Error description
8379 %H - Request domain name
8380 %i - Client IP Address
8382 %O - Unescaped message result from external ACL helper
8383 %o - Message result from external ACL helper
8384 %p - Request Port number
8385 %P - Request Protocol name
8386 %R - Request URL path
8387 %T - Timestamp in RFC 1123 format
8388 %U - Full canonical URL from client
8389 (HTTPS URLs terminate with *)
8390 %u - Full canonical URL from client
8391 %w - Admin email from squid.conf
8393 %% - Literal percent (%) code
8398 OPTIONS INFLUENCING REQUEST FORWARDING
8399 -----------------------------------------------------------------------------
8402 NAME: nonhierarchical_direct
8404 LOC: Config.onoff.nonhierarchical_direct
8407 By default, Squid will send any non-hierarchical requests
8408 (not cacheable request type) direct to origin servers.
8410 When this is set to "off", Squid will prefer to send these
8411 requests to parents.
8413 Note that in most configurations, by turning this off you will only
8414 add latency to these request without any improvement in global hit
8417 This option only sets a preference. If the parent is unavailable a
8418 direct connection to the origin server may still be attempted. To
8419 completely prevent direct connections use never_direct.
8424 LOC: Config.onoff.prefer_direct
8427 Normally Squid tries to use parents for most requests. If you for some
8428 reason like it to first try going direct and only use a parent if
8429 going direct fails set this to on.
8431 By combining nonhierarchical_direct off and prefer_direct on you
8432 can set up Squid to use a parent as a backup path if going direct
8435 Note: If you want Squid to use parents for all requests see
8436 the never_direct directive. prefer_direct only modifies how Squid
8437 acts on cacheable requests.
8440 NAME: cache_miss_revalidate
8444 LOC: Config.onoff.cache_miss_revalidate
8446 RFC 7232 defines a conditional request mechanism to prevent
8447 response objects being unnecessarily transferred over the network.
8448 If that mechanism is used by the client and a cache MISS occurs
8449 it can prevent new cache entries being created.
8451 This option determines whether Squid on cache MISS will pass the
8452 client revalidation request to the server or tries to fetch new
8453 content for caching. It can be useful while the cache is mostly
8454 empty to more quickly have the cache populated by generating
8455 non-conditional GETs.
8457 When set to 'on' (default), Squid will pass all client If-* headers
8458 to the server. This permits server responses without a cacheable
8459 payload to be delivered and on MISS no new cache entry is created.
8461 When set to 'off' and if the request is cacheable, Squid will
8462 remove the clients If-Modified-Since and If-None-Match headers from
8463 the request sent to the server. This requests a 200 status response
8464 from the server to create a new cache entry with.
8469 LOC: Config.accessList.AlwaysDirect
8471 DEFAULT_DOC: Prevent any cache_peer being used for this request.
8473 Usage: always_direct allow|deny [!]aclname ...
8475 Here you can use ACL elements to specify requests which should
8476 ALWAYS be forwarded by Squid to the origin servers without using
8477 any peers. For example, to always directly forward requests for
8478 local servers ignoring any parents or siblings you may have use
8481 acl local-servers dstdomain my.domain.net
8482 always_direct allow local-servers
8484 To always forward FTP requests directly, use
8487 always_direct allow FTP
8489 NOTE: There is a similar, but opposite option named
8490 'never_direct'. You need to be aware that "always_direct deny
8491 foo" is NOT the same thing as "never_direct allow foo". You
8492 may need to use a deny rule to exclude a more-specific case of
8493 some other rule. Example:
8495 acl local-external dstdomain external.foo.net
8496 acl local-servers dstdomain .foo.net
8497 always_direct deny local-external
8498 always_direct allow local-servers
8500 NOTE: If your goal is to make the client forward the request
8501 directly to the origin server bypassing Squid then this needs
8502 to be done in the client configuration. Squid configuration
8503 can only tell Squid how Squid should fetch the object.
8505 NOTE: This directive is not related to caching. The replies
8506 is cached as usual even if you use always_direct. To not cache
8507 the replies see the 'cache' directive.
8509 This clause supports both fast and slow acl types.
8510 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
8515 LOC: Config.accessList.NeverDirect
8517 DEFAULT_DOC: Allow DNS results to be used for this request.
8519 Usage: never_direct allow|deny [!]aclname ...
8521 never_direct is the opposite of always_direct. Please read
8522 the description for always_direct if you have not already.
8524 With 'never_direct' you can use ACL elements to specify
8525 requests which should NEVER be forwarded directly to origin
8526 servers. For example, to force the use of a proxy for all
8527 requests, except those in your local domain use something like:
8529 acl local-servers dstdomain .foo.net
8530 never_direct deny local-servers
8531 never_direct allow all
8533 or if Squid is inside a firewall and there are local intranet
8534 servers inside the firewall use something like:
8536 acl local-intranet dstdomain .foo.net
8537 acl local-external dstdomain external.foo.net
8538 always_direct deny local-external
8539 always_direct allow local-intranet
8540 never_direct allow all
8542 This clause supports both fast and slow acl types.
8543 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
8547 ADVANCED NETWORKING OPTIONS
8548 -----------------------------------------------------------------------------
8551 NAME: incoming_udp_average incoming_icp_average
8554 LOC: Config.comm_incoming.udp.average
8556 Heavy voodoo here. I can't even believe you are reading this.
8557 Are you crazy? Don't even think about adjusting these unless
8558 you understand the algorithms in comm_select.c first!
8561 NAME: incoming_tcp_average incoming_http_average
8564 LOC: Config.comm_incoming.tcp.average
8566 Heavy voodoo here. I can't even believe you are reading this.
8567 Are you crazy? Don't even think about adjusting these unless
8568 you understand the algorithms in comm_select.c first!
8571 NAME: incoming_dns_average
8574 LOC: Config.comm_incoming.dns.average
8576 Heavy voodoo here. I can't even believe you are reading this.
8577 Are you crazy? Don't even think about adjusting these unless
8578 you understand the algorithms in comm_select.c first!
8581 NAME: min_udp_poll_cnt min_icp_poll_cnt
8584 LOC: Config.comm_incoming.udp.min_poll
8586 Heavy voodoo here. I can't even believe you are reading this.
8587 Are you crazy? Don't even think about adjusting these unless
8588 you understand the algorithms in comm_select.c first!
8591 NAME: min_dns_poll_cnt
8594 LOC: Config.comm_incoming.dns.min_poll
8596 Heavy voodoo here. I can't even believe you are reading this.
8597 Are you crazy? Don't even think about adjusting these unless
8598 you understand the algorithms in comm_select.c first!
8601 NAME: min_tcp_poll_cnt min_http_poll_cnt
8604 LOC: Config.comm_incoming.tcp.min_poll
8606 Heavy voodoo here. I can't even believe you are reading this.
8607 Are you crazy? Don't even think about adjusting these unless
8608 you understand the algorithms in comm_select.c first!
8614 LOC: Config.accept_filter
8618 The name of an accept(2) filter to install on Squid's
8619 listen socket(s). This feature is perhaps specific to
8620 FreeBSD and requires support in the kernel.
8622 The 'httpready' filter delays delivering new connections
8623 to Squid until a full HTTP request has been received.
8624 See the accf_http(9) man page for details.
8626 The 'dataready' filter delays delivering new connections
8627 to Squid until there is some data to process.
8628 See the accf_dataready(9) man page for details.
8632 The 'data' filter delays delivering of new connections
8633 to Squid until there is some data to process by TCP_ACCEPT_DEFER.
8634 You may optionally specify a number of seconds to wait by
8635 'data=N' where N is the number of seconds. Defaults to 30
8636 if not specified. See the tcp(7) man page for details.
8639 accept_filter httpready
8644 NAME: client_ip_max_connections
8646 LOC: Config.client_ip_max_connections
8648 DEFAULT_DOC: No limit.
8650 Set an absolute limit on the number of connections a single
8651 client IP can use. Any more than this and Squid will begin to drop
8652 new connections from the client until it closes some links.
8654 Note that this is a global limit. It affects all HTTP, HTCP, Gopher and FTP
8655 connections from the client. For finer control use the ACL access controls.
8657 Requires client_db to be enabled (the default).
8659 WARNING: This may noticably slow down traffic received via external proxies
8660 or NAT devices and cause them to rebound error messages back to their clients.
8663 NAME: tcp_recv_bufsize
8667 DEFAULT_DOC: Use operating system TCP defaults.
8668 LOC: Config.tcpRcvBufsz
8670 Size of receive buffer to set for TCP sockets. Probably just
8671 as easy to change your kernel's default.
8672 Omit from squid.conf to use the default buffer size.
8677 -----------------------------------------------------------------------------
8684 LOC: Adaptation::Icap::TheConfig.onoff
8687 If you want to enable the ICAP module support, set this to on.
8690 NAME: icap_connect_timeout
8693 LOC: Adaptation::Icap::TheConfig.connect_timeout_raw
8696 This parameter specifies how long to wait for the TCP connect to
8697 the requested ICAP server to complete before giving up and either
8698 terminating the HTTP transaction or bypassing the failure.
8700 The default for optional services is peer_connect_timeout.
8701 The default for essential services is connect_timeout.
8702 If this option is explicitly set, its value applies to all services.
8705 NAME: icap_io_timeout
8709 DEFAULT_DOC: Use read_timeout.
8710 LOC: Adaptation::Icap::TheConfig.io_timeout_raw
8713 This parameter specifies how long to wait for an I/O activity on
8714 an established, active ICAP connection before giving up and
8715 either terminating the HTTP transaction or bypassing the
8719 NAME: icap_service_failure_limit
8720 COMMENT: limit [in memory-depth time-units]
8721 TYPE: icap_service_failure_limit
8723 LOC: Adaptation::Icap::TheConfig
8726 The limit specifies the number of failures that Squid tolerates
8727 when establishing a new TCP connection with an ICAP service. If
8728 the number of failures exceeds the limit, the ICAP service is
8729 not used for new ICAP requests until it is time to refresh its
8732 A negative value disables the limit. Without the limit, an ICAP
8733 service will not be considered down due to connectivity failures
8734 between ICAP OPTIONS requests.
8736 Squid forgets ICAP service failures older than the specified
8737 value of memory-depth. The memory fading algorithm
8738 is approximate because Squid does not remember individual
8739 errors but groups them instead, splitting the option
8740 value into ten time slots of equal length.
8742 When memory-depth is 0 and by default this option has no
8743 effect on service failure expiration.
8745 Squid always forgets failures when updating service settings
8746 using an ICAP OPTIONS transaction, regardless of this option
8750 # suspend service usage after 10 failures in 5 seconds:
8751 icap_service_failure_limit 10 in 5 seconds
8754 NAME: icap_service_revival_delay
8757 LOC: Adaptation::Icap::TheConfig.service_revival_delay
8760 The delay specifies the number of seconds to wait after an ICAP
8761 OPTIONS request failure before requesting the options again. The
8762 failed ICAP service is considered "down" until fresh OPTIONS are
8765 The actual delay cannot be smaller than the hardcoded minimum
8766 delay of 30 seconds.
8769 NAME: icap_preview_enable
8773 LOC: Adaptation::Icap::TheConfig.preview_enable
8776 The ICAP Preview feature allows the ICAP server to handle the
8777 HTTP message by looking only at the beginning of the message body
8778 or even without receiving the body at all. In some environments,
8779 previews greatly speedup ICAP processing.
8781 During an ICAP OPTIONS transaction, the server may tell Squid what
8782 HTTP messages should be previewed and how big the preview should be.
8783 Squid will not use Preview if the server did not request one.
8785 To disable ICAP Preview for all ICAP services, regardless of
8786 individual ICAP server OPTIONS responses, set this option to "off".
8788 icap_preview_enable off
8791 NAME: icap_preview_size
8794 LOC: Adaptation::Icap::TheConfig.preview_size
8796 DEFAULT_DOC: No preview sent.
8798 The default size of preview data to be sent to the ICAP server.
8799 This value might be overwritten on a per server basis by OPTIONS requests.
8802 NAME: icap_206_enable
8806 LOC: Adaptation::Icap::TheConfig.allow206_enable
8809 206 (Partial Content) responses is an ICAP extension that allows the
8810 ICAP agents to optionally combine adapted and original HTTP message
8811 content. The decision to combine is postponed until the end of the
8812 ICAP response. Squid supports Partial Content extension by default.
8814 Activation of the Partial Content extension is negotiated with each
8815 ICAP service during OPTIONS exchange. Most ICAP servers should handle
8816 negotation correctly even if they do not support the extension, but
8817 some might fail. To disable Partial Content support for all ICAP
8818 services and to avoid any negotiation, set this option to "off".
8824 NAME: icap_default_options_ttl
8827 LOC: Adaptation::Icap::TheConfig.default_options_ttl
8830 The default TTL value for ICAP OPTIONS responses that don't have
8831 an Options-TTL header.
8834 NAME: icap_persistent_connections
8838 LOC: Adaptation::Icap::TheConfig.reuse_connections
8841 Whether or not Squid should use persistent connections to
8845 NAME: adaptation_send_client_ip icap_send_client_ip
8847 IFDEF: USE_ADAPTATION
8849 LOC: Adaptation::Config::send_client_ip
8852 If enabled, Squid shares HTTP client IP information with adaptation
8853 services. For ICAP, Squid adds the X-Client-IP header to ICAP requests.
8854 For eCAP, Squid sets the libecap::metaClientIp transaction option.
8856 See also: adaptation_uses_indirect_client
8859 NAME: adaptation_send_username icap_send_client_username
8861 IFDEF: USE_ADAPTATION
8863 LOC: Adaptation::Config::send_username
8866 This sends authenticated HTTP client username (if available) to
8867 the adaptation service.
8869 For ICAP, the username value is encoded based on the
8870 icap_client_username_encode option and is sent using the header
8871 specified by the icap_client_username_header option.
8874 NAME: icap_client_username_header
8877 LOC: Adaptation::Icap::TheConfig.client_username_header
8878 DEFAULT: X-Client-Username
8880 ICAP request header name to use for adaptation_send_username.
8883 NAME: icap_client_username_encode
8887 LOC: Adaptation::Icap::TheConfig.client_username_encode
8890 Whether to base64 encode the authenticated client username.
8894 TYPE: icap_service_type
8896 LOC: Adaptation::Icap::TheConfig
8899 Defines a single ICAP service using the following format:
8901 icap_service id vectoring_point uri [option ...]
8904 an opaque identifier or name which is used to direct traffic to
8905 this specific service. Must be unique among all adaptation
8906 services in squid.conf.
8908 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
8909 This specifies at which point of transaction processing the
8910 ICAP service should be activated. *_postcache vectoring points
8911 are not yet supported.
8913 uri: icap://servername:port/servicepath
8914 ICAP server and service location.
8915 icaps://servername:port/servicepath
8916 The "icap:" URI scheme is used for traditional ICAP server and
8917 service location (default port is 1344, connections are not
8918 encrypted). The "icaps:" URI scheme is for Secure ICAP
8919 services that use SSL/TLS-encrypted ICAP connections (by
8920 default, on port 11344).
8922 ICAP does not allow a single service to handle both REQMOD and RESPMOD
8923 transactions. Squid does not enforce that requirement. You can specify
8924 services with the same service_url and different vectoring_points. You
8925 can even specify multiple identical services as long as their
8926 service_names differ.
8928 To activate a service, use the adaptation_access directive. To group
8929 services, use adaptation_service_chain and adaptation_service_set.
8931 Service options are separated by white space. ICAP services support
8932 the following name=value options:
8935 If set to 'on' or '1', the ICAP service is treated as
8936 optional. If the service cannot be reached or malfunctions,
8937 Squid will try to ignore any errors and process the message as
8938 if the service was not enabled. No all ICAP errors can be
8939 bypassed. If set to 0, the ICAP service is treated as
8940 essential and all ICAP errors will result in an error page
8941 returned to the HTTP client.
8943 Bypass is off by default: services are treated as essential.
8946 If set to 'on' or '1', the ICAP service is allowed to
8947 dynamically change the current message adaptation plan by
8948 returning a chain of services to be used next. The services
8949 are specified using the X-Next-Services ICAP response header
8950 value, formatted as a comma-separated list of service names.
8951 Each named service should be configured in squid.conf. Other
8952 services are ignored. An empty X-Next-Services value results
8953 in an empty plan which ends the current adaptation.
8955 Dynamic adaptation plan may cross or cover multiple supported
8956 vectoring points in their natural processing order.
8958 Routing is not allowed by default: the ICAP X-Next-Services
8959 response header is ignored.
8962 Only has effect on split-stack systems. The default on those systems
8963 is to use IPv4-only connections. When set to 'on' this option will
8964 make Squid use IPv6-only connections to contact this ICAP service.
8966 on-overload=block|bypass|wait|force
8967 If the service Max-Connections limit has been reached, do
8968 one of the following for each new ICAP transaction:
8969 * block: send an HTTP error response to the client
8970 * bypass: ignore the "over-connected" ICAP service
8971 * wait: wait (in a FIFO queue) for an ICAP connection slot
8972 * force: proceed, ignoring the Max-Connections limit
8974 In SMP mode with N workers, each worker assumes the service
8975 connection limit is Max-Connections/N, even though not all
8976 workers may use a given service.
8978 The default value is "bypass" if service is bypassable,
8979 otherwise it is set to "wait".
8983 Use the given number as the Max-Connections limit, regardless
8984 of the Max-Connections value given by the service, if any.
8986 connection-encryption=on|off
8987 Determines the ICAP service effect on the connections_encrypted
8990 The default is "on" for Secure ICAP services (i.e., those
8991 with the icaps:// service URIs scheme) and "off" for plain ICAP
8994 Does not affect ICAP connections (e.g., does not turn Secure
8997 ==== ICAPS / TLS OPTIONS ====
8999 These options are used for Secure ICAP (icaps://....) services only.
9001 tls-cert=/path/to/ssl/certificate
9002 A client X.509 certificate to use when connecting to
9005 tls-key=/path/to/ssl/key
9006 The private key corresponding to the previous
9009 If tls-key= is not specified tls-cert= is assumed to
9010 reference a PEM file containing both the certificate
9013 tls-cipher=... The list of valid TLS/SSL ciphers to use when connecting
9014 to this icap server.
9017 The minimum TLS protocol version to permit. To control
9018 SSLv3 use the tls-options= parameter.
9019 Supported Values: 1.0 (default), 1.1, 1.2
9021 tls-options=... Specify various OpenSSL library options:
9023 NO_SSLv3 Disallow the use of SSLv3
9026 Always create a new key when using
9027 temporary/ephemeral DH key exchanges
9029 ALL Enable various bug workarounds
9030 suggested as "harmless" by OpenSSL
9031 Be warned that this reduces SSL/TLS
9032 strength to some attacks.
9034 See the OpenSSL SSL_CTX_set_options documentation for a
9035 more complete list. Options relevant only to SSLv2 are
9038 tls-cafile= PEM file containing CA certificates to use when verifying
9039 the icap server certificate.
9040 Use to specify intermediate CA certificate(s) if not sent
9041 by the server. Or the full CA chain for the server when
9042 using the tls-default-ca=off flag.
9043 May be repeated to load multiple files.
9045 tls-capath=... A directory containing additional CA certificates to
9046 use when verifying the icap server certificate.
9047 Requires OpenSSL or LibreSSL.
9049 tls-crlfile=... A certificate revocation list file to use when
9050 verifying the icap server certificate.
9052 tls-flags=... Specify various flags modifying the Squid TLS implementation:
9055 Accept certificates even if they fail to
9058 Don't verify the icap server certificate
9059 matches the server name
9061 tls-default-ca[=off]
9062 Whether to use the system Trusted CAs. Default is ON.
9064 tls-domain= The icap server name as advertised in it's certificate.
9065 Used for verifying the correctness of the received icap
9066 server certificate. If not specified the icap server
9067 hostname extracted from ICAP URI will be used.
9069 Older icap_service format without optional named parameters is
9070 deprecated but supported for backward compatibility.
9073 icap_service svcBlocker reqmod_precache icap://icap1.mydomain.net:1344/reqmod bypass=0
9074 icap_service svcLogger reqmod_precache icaps://icap2.mydomain.net:11344/reqmod routing=on
9078 TYPE: icap_class_type
9083 This deprecated option was documented to define an ICAP service
9084 chain, even though it actually defined a set of similar, redundant
9085 services, and the chains were not supported.
9087 To define a set of redundant services, please use the
9088 adaptation_service_set directive. For service chains, use
9089 adaptation_service_chain.
9093 TYPE: icap_access_type
9098 This option is deprecated. Please use adaptation_access, which
9099 has the same ICAP functionality, but comes with better
9100 documentation, and eCAP support.
9105 -----------------------------------------------------------------------------
9112 LOC: Adaptation::Ecap::TheConfig.onoff
9115 Controls whether eCAP support is enabled.
9119 TYPE: ecap_service_type
9121 LOC: Adaptation::Ecap::TheConfig
9124 Defines a single eCAP service
9126 ecap_service id vectoring_point uri [option ...]
9129 an opaque identifier or name which is used to direct traffic to
9130 this specific service. Must be unique among all adaptation
9131 services in squid.conf.
9133 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
9134 This specifies at which point of transaction processing the
9135 eCAP service should be activated. *_postcache vectoring points
9136 are not yet supported.
9138 uri: ecap://vendor/service_name?custom&cgi=style¶meters=optional
9139 Squid uses the eCAP service URI to match this configuration
9140 line with one of the dynamically loaded services. Each loaded
9141 eCAP service must have a unique URI. Obtain the right URI from
9142 the service provider.
9144 To activate a service, use the adaptation_access directive. To group
9145 services, use adaptation_service_chain and adaptation_service_set.
9147 Service options are separated by white space. eCAP services support
9148 the following name=value options:
9151 If set to 'on' or '1', the eCAP service is treated as optional.
9152 If the service cannot be reached or malfunctions, Squid will try
9153 to ignore any errors and process the message as if the service
9154 was not enabled. No all eCAP errors can be bypassed.
9155 If set to 'off' or '0', the eCAP service is treated as essential
9156 and all eCAP errors will result in an error page returned to the
9159 Bypass is off by default: services are treated as essential.
9162 If set to 'on' or '1', the eCAP service is allowed to
9163 dynamically change the current message adaptation plan by
9164 returning a chain of services to be used next.
9166 Dynamic adaptation plan may cross or cover multiple supported
9167 vectoring points in their natural processing order.
9169 Routing is not allowed by default.
9171 connection-encryption=on|off
9172 Determines the eCAP service effect on the connections_encrypted
9175 Defaults to "on", which does not taint the master transaction
9178 Does not affect eCAP API calls.
9180 Older ecap_service format without optional named parameters is
9181 deprecated but supported for backward compatibility.
9185 ecap_service s1 reqmod_precache ecap://filters.R.us/leakDetector?on_error=block bypass=off
9186 ecap_service s2 respmod_precache ecap://filters.R.us/virusFilter config=/etc/vf.cfg bypass=on
9189 NAME: loadable_modules
9191 IFDEF: USE_LOADABLE_MODULES
9192 LOC: Config.loadable_module_names
9195 Instructs Squid to load the specified dynamic module(s) or activate
9196 preloaded module(s).
9198 loadable_modules @DEFAULT_PREFIX@/lib/MinimalAdapter.so
9202 MESSAGE ADAPTATION OPTIONS
9203 -----------------------------------------------------------------------------
9206 NAME: adaptation_service_set
9207 TYPE: adaptation_service_set_type
9208 IFDEF: USE_ADAPTATION
9213 Configures an ordered set of similar, redundant services. This is
9214 useful when hot standby or backup adaptation servers are available.
9216 adaptation_service_set set_name service_name1 service_name2 ...
9218 The named services are used in the set declaration order. The first
9219 applicable adaptation service from the set is used first. The next
9220 applicable service is tried if and only if the transaction with the
9221 previous service fails and the message waiting to be adapted is still
9224 When adaptation starts, broken services are ignored as if they were
9225 not a part of the set. A broken service is a down optional service.
9227 The services in a set must be attached to the same vectoring point
9228 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
9230 If all services in a set are optional then adaptation failures are
9231 bypassable. If all services in the set are essential, then a
9232 transaction failure with one service may still be retried using
9233 another service from the set, but when all services fail, the master
9234 transaction fails as well.
9236 A set may contain a mix of optional and essential services, but that
9237 is likely to lead to surprising results because broken services become
9238 ignored (see above), making previously bypassable failures fatal.
9239 Technically, it is the bypassability of the last failed service that
9242 See also: adaptation_access adaptation_service_chain
9245 adaptation_service_set svcBlocker urlFilterPrimary urlFilterBackup
9246 adaptation service_set svcLogger loggerLocal loggerRemote
9249 NAME: adaptation_service_chain
9250 TYPE: adaptation_service_chain_type
9251 IFDEF: USE_ADAPTATION
9256 Configures a list of complementary services that will be applied
9257 one-by-one, forming an adaptation chain or pipeline. This is useful
9258 when Squid must perform different adaptations on the same message.
9260 adaptation_service_chain chain_name service_name1 svc_name2 ...
9262 The named services are used in the chain declaration order. The first
9263 applicable adaptation service from the chain is used first. The next
9264 applicable service is applied to the successful adaptation results of
9265 the previous service in the chain.
9267 When adaptation starts, broken services are ignored as if they were
9268 not a part of the chain. A broken service is a down optional service.
9270 Request satisfaction terminates the adaptation chain because Squid
9271 does not currently allow declaration of RESPMOD services at the
9272 "reqmod_precache" vectoring point (see icap_service or ecap_service).
9274 The services in a chain must be attached to the same vectoring point
9275 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
9277 A chain may contain a mix of optional and essential services. If an
9278 essential adaptation fails (or the failure cannot be bypassed for
9279 other reasons), the master transaction fails. Otherwise, the failure
9280 is bypassed as if the failed adaptation service was not in the chain.
9282 See also: adaptation_access adaptation_service_set
9285 adaptation_service_chain svcRequest requestLogger urlFilter leakDetector
9288 NAME: adaptation_access
9289 TYPE: adaptation_access_type
9290 IFDEF: USE_ADAPTATION
9293 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
9295 Sends an HTTP transaction to an ICAP or eCAP adaptation service.
9297 adaptation_access service_name allow|deny [!]aclname...
9298 adaptation_access set_name allow|deny [!]aclname...
9300 At each supported vectoring point, the adaptation_access
9301 statements are processed in the order they appear in this
9302 configuration file. Statements pointing to the following services
9303 are ignored (i.e., skipped without checking their ACL):
9305 - services serving different vectoring points
9306 - "broken-but-bypassable" services
9307 - "up" services configured to ignore such transactions
9308 (e.g., based on the ICAP Transfer-Ignore header).
9310 When a set_name is used, all services in the set are checked
9311 using the same rules, to find the first applicable one. See
9312 adaptation_service_set for details.
9314 If an access list is checked and there is a match, the
9315 processing stops: For an "allow" rule, the corresponding
9316 adaptation service is used for the transaction. For a "deny"
9317 rule, no adaptation service is activated.
9319 It is currently not possible to apply more than one adaptation
9320 service at the same vectoring point to the same HTTP transaction.
9322 See also: icap_service and ecap_service
9325 adaptation_access service_1 allow all
9328 NAME: adaptation_service_iteration_limit
9330 IFDEF: USE_ADAPTATION
9331 LOC: Adaptation::Config::service_iteration_limit
9334 Limits the number of iterations allowed when applying adaptation
9335 services to a message. If your longest adaptation set or chain
9336 may have more than 16 services, increase the limit beyond its
9337 default value of 16. If detecting infinite iteration loops sooner
9338 is critical, make the iteration limit match the actual number
9339 of services in your longest adaptation set or chain.
9341 Infinite adaptation loops are most likely with routing services.
9343 See also: icap_service routing=1
9346 NAME: adaptation_masterx_shared_names
9348 IFDEF: USE_ADAPTATION
9349 LOC: Adaptation::Config::masterx_shared_name
9352 For each master transaction (i.e., the HTTP request and response
9353 sequence, including all related ICAP and eCAP exchanges), Squid
9354 maintains a table of metadata. The table entries are (name, value)
9355 pairs shared among eCAP and ICAP exchanges. The table is destroyed
9356 with the master transaction.
9358 This option specifies the table entry names that Squid must accept
9359 from and forward to the adaptation transactions.
9361 An ICAP REQMOD or RESPMOD transaction may set an entry in the
9362 shared table by returning an ICAP header field with a name
9363 specified in adaptation_masterx_shared_names.
9365 An eCAP REQMOD or RESPMOD transaction may set an entry in the
9366 shared table by implementing the libecap::visitEachOption() API
9367 to provide an option with a name specified in
9368 adaptation_masterx_shared_names.
9370 Squid will store and forward the set entry to subsequent adaptation
9371 transactions within the same master transaction scope.
9373 Only one shared entry name is supported at this time.
9376 # share authentication information among ICAP services
9377 adaptation_masterx_shared_names X-Subscriber-ID
9380 NAME: adaptation_meta
9382 IFDEF: USE_ADAPTATION
9383 LOC: Adaptation::Config::metaHeaders
9386 This option allows Squid administrator to add custom ICAP request
9387 headers or eCAP options to Squid ICAP requests or eCAP transactions.
9388 Use it to pass custom authentication tokens and other
9389 transaction-state related meta information to an ICAP/eCAP service.
9391 The addition of a meta header is ACL-driven:
9392 adaptation_meta name value [!]aclname ...
9394 Processing for a given header name stops after the first ACL list match.
9395 Thus, it is impossible to add two headers with the same name. If no ACL
9396 lists match for a given header name, no such header is added. For
9399 # do not debug transactions except for those that need debugging
9400 adaptation_meta X-Debug 1 needs_debugging
9402 # log all transactions except for those that must remain secret
9403 adaptation_meta X-Log 1 !keep_secret
9405 # mark transactions from users in the "G 1" group
9406 adaptation_meta X-Authenticated-Groups "G 1" authed_as_G1
9408 The "value" parameter may be a regular squid.conf token or a "double
9409 quoted string". Within the quoted string, use backslash (\) to escape
9410 any character, which is currently only useful for escaping backslashes
9411 and double quotes. For example,
9412 "this string has one backslash (\\) and two \"quotes\""
9414 Used adaptation_meta header values may be logged via %note
9415 logformat code. If multiple adaptation_meta headers with the same name
9416 are used during master transaction lifetime, the header values are
9417 logged in the order they were used and duplicate values are ignored
9418 (only the first repeated value will be logged).
9424 LOC: Adaptation::Icap::TheConfig.repeat
9425 DEFAULT_IF_NONE: deny all
9427 This ACL determines which retriable ICAP transactions are
9428 retried. Transactions that received a complete ICAP response
9429 and did not have to consume or produce HTTP bodies to receive
9430 that response are usually retriable.
9432 icap_retry allow|deny [!]aclname ...
9434 Squid automatically retries some ICAP I/O timeouts and errors
9435 due to persistent connection race conditions.
9437 See also: icap_retry_limit
9440 NAME: icap_retry_limit
9443 LOC: Adaptation::Icap::TheConfig.repeat_limit
9445 DEFAULT_DOC: No retries are allowed.
9447 Limits the number of retries allowed.
9449 Communication errors due to persistent connection race
9450 conditions are unavoidable, automatically retried, and do not
9451 count against this limit.
9453 See also: icap_retry
9459 -----------------------------------------------------------------------------
9462 NAME: check_hostnames
9465 LOC: Config.onoff.check_hostnames
9467 For security and stability reasons Squid can check
9468 hostnames for Internet standard RFC compliance. If you want
9469 Squid to perform these checks turn this directive on.
9472 NAME: allow_underscore
9475 LOC: Config.onoff.allow_underscore
9477 Underscore characters is not strictly allowed in Internet hostnames
9478 but nevertheless used by many sites. Set this to off if you want
9479 Squid to be strict about the standard.
9480 This check is performed only when check_hostnames is set to on.
9483 NAME: dns_retransmit_interval
9486 LOC: Config.Timeout.idns_retransmit
9488 Initial retransmit interval for DNS queries. The interval is
9489 doubled each time all configured DNS servers have been tried.
9495 LOC: Config.Timeout.idns_query
9497 DNS Query timeout. If no response is received to a DNS query
9498 within this time all DNS servers for the queried domain
9499 are assumed to be unavailable.
9502 NAME: dns_packet_max
9504 DEFAULT_DOC: EDNS disabled
9506 LOC: Config.dns.packet_max
9508 Maximum number of bytes packet size to advertise via EDNS.
9509 Set to "none" to disable EDNS large packet support.
9511 For legacy reasons DNS UDP replies will default to 512 bytes which
9512 is too small for many responses. EDNS provides a means for Squid to
9513 negotiate receiving larger responses back immediately without having
9514 to failover with repeat requests. Responses larger than this limit
9515 will retain the old behaviour of failover to TCP DNS.
9517 Squid has no real fixed limit internally, but allowing packet sizes
9518 over 1500 bytes requires network jumbogram support and is usually not
9521 WARNING: The RFC also indicates that some older resolvers will reply
9522 with failure of the whole request if the extension is added. Some
9523 resolvers have already been identified which will reply with mangled
9524 EDNS response on occasion. Usually in response to many-KB jumbogram
9525 sizes being advertised by Squid.
9526 Squid will currently treat these both as an unable-to-resolve domain
9527 even if it would be resolvable without EDNS.
9534 DEFAULT_DOC: Search for single-label domain names is disabled.
9535 LOC: Config.onoff.res_defnames
9537 Normally the RES_DEFNAMES resolver option is disabled
9538 (see res_init(3)). This prevents caches in a hierarchy
9539 from interpreting single-component hostnames locally. To allow
9540 Squid to handle single-component names, enable this option.
9543 NAME: dns_multicast_local
9547 DEFAULT_DOC: Search for .local and .arpa names is disabled.
9548 LOC: Config.onoff.dns_mdns
9550 When set to on, Squid sends multicast DNS lookups on the local
9551 network for domains ending in .local and .arpa.
9552 This enables local servers and devices to be contacted in an
9553 ad-hoc or zero-configuration network environment.
9556 NAME: dns_nameservers
9559 DEFAULT_DOC: Use operating system definitions
9560 LOC: Config.dns.nameservers
9562 Use this if you want to specify a list of DNS name servers
9563 (IP addresses) to use instead of those given in your
9564 /etc/resolv.conf file.
9566 On Windows platforms, if no value is specified here or in
9567 the /etc/resolv.conf file, the list of DNS name servers are
9568 taken from the Windows registry, both static and dynamic DHCP
9569 configurations are supported.
9571 Example: dns_nameservers 10.0.0.1 192.172.0.4
9576 DEFAULT: @DEFAULT_HOSTS@
9577 LOC: Config.etcHostsPath
9579 Location of the host-local IP name-address associations
9580 database. Most Operating Systems have such a file on different
9582 - Un*X & Linux: /etc/hosts
9583 - Windows NT/2000: %SystemRoot%\system32\drivers\etc\hosts
9584 (%SystemRoot% value install default is c:\winnt)
9585 - Windows XP/2003: %SystemRoot%\system32\drivers\etc\hosts
9586 (%SystemRoot% value install default is c:\windows)
9587 - Windows 9x/Me: %windir%\hosts
9588 (%windir% value is usually c:\windows)
9589 - Cygwin: /etc/hosts
9591 The file contains newline-separated definitions, in the
9592 form ip_address_in_dotted_form name [name ...] names are
9593 whitespace-separated. Lines beginning with an hash (#)
9594 character are comments.
9596 The file is checked at startup and upon configuration.
9597 If set to 'none', it won't be checked.
9598 If append_domain is used, that domain will be added to
9599 domain-local (i.e. not containing any dot character) host
9605 LOC: Config.appendDomain
9607 DEFAULT_DOC: Use operating system definitions
9609 Appends local domain name to hostnames without any dots in
9610 them. append_domain must begin with a period.
9612 Be warned there are now Internet names with no dots in
9613 them using only top-domain names, so setting this may
9614 cause some Internet sites to become unavailable.
9617 append_domain .yourdomain.com
9620 NAME: ignore_unknown_nameservers
9622 LOC: Config.onoff.ignore_unknown_nameservers
9625 By default Squid checks that DNS responses are received
9626 from the same IP addresses they are sent to. If they
9627 don't match, Squid ignores the response and writes a warning
9628 message to cache.log. You can allow responses from unknown
9629 nameservers by setting this option to 'off'.
9635 LOC: Config.dns.v4_first
9637 With the IPv6 Internet being as fast or faster than IPv4 Internet
9638 for most networks Squid prefers to contact websites over IPv6.
9640 This option reverses the order of preference to make Squid contact
9641 dual-stack websites over IPv4 first. Squid will still perform both
9642 IPv6 and IPv4 DNS lookups before connecting.
9645 This option will restrict the situations under which IPv6
9646 connectivity is used (and tested). Hiding network problems
9647 which would otherwise be detected and warned about.
9651 COMMENT: (number of entries)
9654 LOC: Config.ipcache.size
9656 Maximum number of DNS IP cache entries.
9663 LOC: Config.ipcache.low
9670 LOC: Config.ipcache.high
9672 The size, low-, and high-water marks for the IP cache.
9675 NAME: fqdncache_size
9676 COMMENT: (number of entries)
9679 LOC: Config.fqdncache.size
9681 Maximum number of FQDN cache entries.
9686 -----------------------------------------------------------------------------
9689 NAME: configuration_includes_quoted_values
9691 TYPE: configuration_includes_quoted_values
9693 LOC: ConfigParser::RecognizeQuotedValues
9695 If set, Squid will recognize each "quoted string" after a configuration
9696 directive as a single parameter. The quotes are stripped before the
9697 parameter value is interpreted or used.
9698 See "Values with spaces, quotes, and other special characters"
9699 section for more details.
9706 LOC: Config.onoff.mem_pools
9708 If set, Squid will keep pools of allocated (but unused) memory
9709 available for future use. If memory is a premium on your
9710 system and you believe your malloc library outperforms Squid
9711 routines, disable this.
9714 NAME: memory_pools_limit
9718 LOC: Config.MemPools.limit
9720 Used only with memory_pools on:
9721 memory_pools_limit 50 MB
9723 If set to a non-zero value, Squid will keep at most the specified
9724 limit of allocated (but unused) memory in memory pools. All free()
9725 requests that exceed this limit will be handled by your malloc
9726 library. Squid does not pre-allocate any memory, just safe-keeps
9727 objects that otherwise would be free()d. Thus, it is safe to set
9728 memory_pools_limit to a reasonably high value even if your
9729 configuration will use less memory.
9731 If set to none, Squid will keep all memory it can. That is, there
9732 will be no limit on the total amount of memory used for safe-keeping.
9734 To disable memory allocation optimization, do not set
9735 memory_pools_limit to 0 or none. Set memory_pools to "off" instead.
9737 An overhead for maintaining memory pools is not taken into account
9738 when the limit is checked. This overhead is close to four bytes per
9739 object kept. However, pools may actually _save_ memory because of
9740 reduced memory thrashing in your malloc library.
9744 COMMENT: on|off|transparent|truncate|delete
9747 LOC: opt_forwarded_for
9749 If set to "on", Squid will append your client's IP address
9750 in the HTTP requests it forwards. By default it looks like:
9752 X-Forwarded-For: 192.1.2.3
9754 If set to "off", it will appear as
9756 X-Forwarded-For: unknown
9758 If set to "transparent", Squid will not alter the
9759 X-Forwarded-For header in any way.
9761 If set to "delete", Squid will delete the entire
9762 X-Forwarded-For header.
9764 If set to "truncate", Squid will remove all existing
9765 X-Forwarded-For entries, and place the client IP as the sole entry.
9768 NAME: cachemgr_passwd
9769 TYPE: cachemgrpasswd
9771 DEFAULT_DOC: No password. Actions which require password are denied.
9772 LOC: Config.passwd_list
9774 Specify passwords for cachemgr operations.
9776 Usage: cachemgr_passwd password action action ...
9778 Some valid actions are (see cache manager menu for a full list):
9818 * Indicates actions which will not be performed without a
9819 valid password, others can be performed if not listed here.
9821 To disable an action, set the password to "disable".
9822 To allow performing an action without a password, set the
9825 Use the keyword "all" to set the same password for all actions.
9828 cachemgr_passwd secret shutdown
9829 cachemgr_passwd lesssssssecret info stats/objects
9830 cachemgr_passwd disable all
9837 LOC: Config.onoff.client_db
9839 If you want to disable collecting per-client statistics,
9840 turn off client_db here.
9843 NAME: refresh_all_ims
9847 LOC: Config.onoff.refresh_all_ims
9849 When you enable this option, squid will always check
9850 the origin server for an update when a client sends an
9851 If-Modified-Since request. Many browsers use IMS
9852 requests when the user requests a reload, and this
9853 ensures those clients receive the latest version.
9855 By default (off), squid may return a Not Modified response
9856 based on the age of the cached version.
9859 NAME: reload_into_ims
9860 IFDEF: USE_HTTP_VIOLATIONS
9864 LOC: Config.onoff.reload_into_ims
9866 When you enable this option, client no-cache or ``reload''
9867 requests will be changed to If-Modified-Since requests.
9868 Doing this VIOLATES the HTTP standard. Enabling this
9869 feature could make you liable for problems which it
9872 see also refresh_pattern for a more selective approach.
9875 NAME: connect_retries
9877 LOC: Config.connect_retries
9879 DEFAULT_DOC: Do not retry failed connections.
9881 This sets the maximum number of connection attempts made for each
9882 TCP connection. The connect_retries attempts must all still
9883 complete within the connection timeout period.
9885 The default is not to re-try if the first connection attempt fails.
9886 The (not recommended) maximum is 10 tries.
9888 A warning message will be generated if it is set to a too-high
9889 value and the configured value will be over-ridden.
9891 Note: These re-tries are in addition to forward_max_tries
9892 which limit how many different addresses may be tried to find
9896 NAME: retry_on_error
9898 LOC: Config.retry.onerror
9901 If set to ON Squid will automatically retry requests when
9902 receiving an error response with status 403 (Forbidden),
9903 500 (Internal Error), 501 or 503 (Service not available).
9904 Status 502 and 504 (Gateway errors) are always retried.
9906 This is mainly useful if you are in a complex cache hierarchy to
9907 work around access control errors.
9909 NOTE: This retry will attempt to find another working destination.
9910 Which is different from the server which just failed.
9913 NAME: as_whois_server
9915 LOC: Config.as_whois_server
9916 DEFAULT: whois.ra.net
9918 WHOIS server to query for AS numbers. NOTE: AS numbers are
9919 queried only when Squid starts up, not for every request.
9924 LOC: Config.onoff.offline
9927 Enable this option and Squid will never try to validate cached
9931 NAME: uri_whitespace
9932 TYPE: uri_whitespace
9933 LOC: Config.uri_whitespace
9936 What to do with requests that have whitespace characters in the
9939 strip: The whitespace characters are stripped out of the URL.
9940 This is the behavior recommended by RFC2396 and RFC3986
9941 for tolerant handling of generic URI.
9942 NOTE: This is one difference between generic URI and HTTP URLs.
9944 deny: The request is denied. The user receives an "Invalid
9946 This is the behaviour recommended by RFC2616 for safe
9947 handling of HTTP request URL.
9949 allow: The request is allowed and the URI is not changed. The
9950 whitespace characters remain in the URI. Note the
9951 whitespace is passed to redirector processes if they
9953 Note this may be considered a violation of RFC2616
9954 request parsing where whitespace is prohibited in the
9957 encode: The request is allowed and the whitespace characters are
9958 encoded according to RFC1738.
9960 chop: The request is allowed and the URI is chopped at the
9964 NOTE the current Squid implementation of encode and chop violates
9965 RFC2616 by not using a 301 redirect after altering the URL.
9970 LOC: Config.chroot_dir
9973 Specifies a directory where Squid should do a chroot() while
9974 initializing. This also causes Squid to fully drop root
9975 privileges after initializing. This means, for example, if you
9976 use a HTTP port less than 1024 and try to reconfigure, you may
9977 get an error saying that Squid can not open the port.
9980 NAME: balance_on_multiple_ip
9982 LOC: Config.onoff.balance_on_multiple_ip
9985 Modern IP resolvers in squid sort lookup results by preferred access.
9986 By default squid will use these IP in order and only rotates to
9987 the next listed when the most preffered fails.
9989 Some load balancing servers based on round robin DNS have been
9990 found not to preserve user session state across requests
9991 to different IP addresses.
9993 Enabling this directive Squid rotates IP's per request.
9996 NAME: pipeline_prefetch
9997 TYPE: pipelinePrefetch
9998 LOC: Config.pipeline_max_prefetch
10000 DEFAULT_DOC: Do not pre-parse pipelined requests.
10002 HTTP clients may send a pipeline of 1+N requests to Squid using a
10003 single connection, without waiting for Squid to respond to the first
10004 of those requests. This option limits the number of concurrent
10005 requests Squid will try to handle in parallel. If set to N, Squid
10006 will try to receive and process up to 1+N requests on the same
10007 connection concurrently.
10009 Defaults to 0 (off) for bandwidth management and access logging
10012 NOTE: pipelining requires persistent connections to clients.
10014 WARNING: pipelining breaks NTLM and Negotiate/Kerberos authentication.
10017 NAME: high_response_time_warning
10020 LOC: Config.warnings.high_rptm
10022 DEFAULT_DOC: disabled.
10024 If the one-minute median response time exceeds this value,
10025 Squid prints a WARNING with debug level 0 to get the
10026 administrators attention. The value is in milliseconds.
10029 NAME: high_page_fault_warning
10031 LOC: Config.warnings.high_pf
10033 DEFAULT_DOC: disabled.
10035 If the one-minute average page fault rate exceeds this
10036 value, Squid prints a WARNING with debug level 0 to get
10037 the administrators attention. The value is in page faults
10041 NAME: high_memory_warning
10043 LOC: Config.warnings.high_memory
10044 IFDEF: HAVE_MSTATS&&HAVE_GNUMALLOC_H
10046 DEFAULT_DOC: disabled.
10048 If the memory usage (as determined by gnumalloc, if available and used)
10049 exceeds this amount, Squid prints a WARNING with debug level 0 to get
10050 the administrators attention.
10052 # TODO: link high_memory_warning to mempools?
10054 NAME: sleep_after_fork
10055 COMMENT: (microseconds)
10057 LOC: Config.sleep_after_fork
10060 When this is set to a non-zero value, the main Squid process
10061 sleeps the specified number of microseconds after a fork()
10062 system call. This sleep may help the situation where your
10063 system reports fork() failures due to lack of (virtual)
10064 memory. Note, however, if you have a lot of child
10065 processes, these sleep delays will add up and your
10066 Squid will not service requests for some amount of time
10067 until all the child processes have been started.
10068 On Windows value less then 1000 (1 milliseconds) are
10072 NAME: windows_ipaddrchangemonitor
10073 IFDEF: _SQUID_WINDOWS_
10077 LOC: Config.onoff.WIN32_IpAddrChangeMonitor
10079 On Windows Squid by default will monitor IP address changes and will
10080 reconfigure itself after any detected event. This is very useful for
10081 proxies connected to internet with dial-up interfaces.
10082 In some cases (a Proxy server acting as VPN gateway is one) it could be
10083 desiderable to disable this behaviour setting this to 'off'.
10084 Note: after changing this, Squid service must be restarted.
10089 IFDEF: USE_SQUID_EUI
10091 LOC: Eui::TheConfig.euiLookup
10093 Whether to lookup the EUI or MAC address of a connected client.
10096 NAME: max_filedescriptors max_filedesc
10099 DEFAULT_DOC: Use operating system limits set by ulimit.
10100 LOC: Config.max_filedescriptors
10102 Reduce the maximum number of filedescriptors supported below
10103 the usual operating system defaults.
10105 Remove from squid.conf to inherit the current ulimit setting.
10107 Note: Changing this requires a restart of Squid. Also
10108 not all I/O types supports large values (eg on Windows).
10111 NAME: force_request_body_continuation
10113 LOC: Config.accessList.forceRequestBodyContinuation
10115 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
10117 This option controls how Squid handles data upload requests from HTTP
10118 and FTP agents that require a "Please Continue" control message response
10119 to actually send the request body to Squid. It is mostly useful in
10120 adaptation environments.
10122 When Squid receives an HTTP request with an "Expect: 100-continue"
10123 header or an FTP upload command (e.g., STOR), Squid normally sends the
10124 request headers or FTP command information to an adaptation service (or
10125 peer) and waits for a response. Most adaptation services (and some
10126 broken peers) may not respond to Squid at that stage because they may
10127 decide to wait for the HTTP request body or FTP data transfer. However,
10128 that request body or data transfer may never come because Squid has not
10129 responded with the HTTP 100 or FTP 150 (Please Continue) control message
10130 to the request sender yet!
10132 An allow match tells Squid to respond with the HTTP 100 or FTP 150
10133 (Please Continue) control message on its own, before forwarding the
10134 request to an adaptation service or peer. Such a response usually forces
10135 the request sender to proceed with sending the body. A deny match tells
10136 Squid to delay that control response until the origin server confirms
10137 that the request body is needed. Delaying is the default behavior.
10140 NAME: server_pconn_for_nonretriable
10143 DEFAULT_DOC: Open new connections for forwarding requests Squid cannot retry safely.
10144 LOC: Config.accessList.serverPconnForNonretriable
10146 This option provides fine-grained control over persistent connection
10147 reuse when forwarding HTTP requests that Squid cannot retry. It is useful
10148 in environments where opening new connections is very expensive
10149 (e.g., all connections are secured with TLS with complex client and server
10150 certificate validation) and race conditions associated with persistent
10151 connections are very rare and/or only cause minor problems.
10153 HTTP prohibits retrying unsafe and non-idempotent requests (e.g., POST).
10154 Squid limitations also prohibit retrying all requests with bodies (e.g., PUT).
10155 By default, when forwarding such "risky" requests, Squid opens a new
10156 connection to the server or cache_peer, even if there is an idle persistent
10157 connection available. When Squid is configured to risk sending a non-retriable
10158 request on a previously used persistent connection, and the server closes
10159 the connection before seeing that risky request, the user gets an error response
10160 from Squid. In most cases, that error response will be HTTP 502 (Bad Gateway)
10161 with ERR_ZERO_SIZE_OBJECT or ERR_WRITE_ERROR (peer connection reset) error detail.
10163 If an allow rule matches, Squid reuses an available idle persistent connection
10164 (if any) for the request that Squid cannot retry. If a deny rule matches, then
10165 Squid opens a new connection for the request that Squid cannot retry.
10167 This option does not affect requests that Squid can retry. They will reuse idle
10168 persistent connections (if any).
10170 This clause only supports fast acl types.
10171 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
10174 acl SpeedIsWorthTheRisk method POST
10175 server_pconn_for_nonretriable allow SpeedIsWorthTheRisk
projects / thirdparty / squid.git / blob