1 ## Copyright (C) 1996-2017 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.
477 OPTIONS FOR AUTHENTICATION
478 -----------------------------------------------------------------------------
484 LOC: Auth::TheConfig.schemes
487 This is used to define parameters for the various authentication
488 schemes supported by Squid.
490 format: auth_param scheme parameter [setting]
492 The order in which authentication schemes are presented to the client is
493 dependent on the order the scheme first appears in config file. IE
494 has a bug (it's not RFC 2617 compliant) in that it will use the basic
495 scheme if basic is the first entry presented, even if more secure
496 schemes are presented. For now use the order in the recommended
497 settings section below. If other browsers have difficulties (don't
498 recognize the schemes offered even if you are using basic) either
499 put basic first, or disable the other schemes (by commenting out their
502 Once an authentication scheme is fully configured, it can only be
503 shutdown by shutting squid down and restarting. Changes can be made on
504 the fly and activated with a reconfigure. I.E. You can change to a
505 different helper, but not unconfigure the helper completely.
507 Please note that while this directive defines how Squid processes
508 authentication it does not automatically activate authentication.
509 To use authentication you must in addition make use of ACLs based
510 on login name in http_access (proxy_auth, proxy_auth_regex or
511 external with %LOGIN used in the format tag). The browser will be
512 challenged for authentication on the first such acl encountered
513 in http_access processing and will also be re-challenged for new
514 login credentials if the request is being denied by a proxy_auth
517 WARNING: authentication can't be used in a transparently intercepting
518 proxy as the client then thinks it is talking to an origin server and
519 not the proxy. This is a limitation of bending the TCP/IP protocol to
520 transparently intercepting port 80, not a limitation in Squid.
521 Ports flagged 'transparent', 'intercept', or 'tproxy' have
522 authentication disabled.
524 === Parameters common to all schemes. ===
527 Specifies the command for the external authenticator.
529 By default, each authentication scheme is not used unless a
530 program is specified.
532 See http://wiki.squid-cache.org/Features/AddonHelpers for
533 more details on helper operations and creating your own.
536 Specifies a string to be append to request line format for
537 the authentication helper. "Quoted" format values may contain
538 spaces and logformat %macros. In theory, any logformat %macro
539 can be used. In practice, a %macro expands as a dash (-) if
540 the helper request is sent before the required macro
541 information is available to Squid.
543 By default, Squid uses request formats provided in
544 scheme-specific examples below (search for %credentials).
546 The expanded key_extras value is added to the Squid credentials
547 cache and, hence, will affect authentication. It can be used to
548 autenticate different users with identical user names (e.g.,
549 when user authentication depends on http_port).
551 Avoid adding frequently changing information to key_extras. For
552 example, if you add user source IP, and it changes frequently
553 in your environment, then max_user_ip ACL is going to treat
554 every user+IP combination as a unique "user", breaking the ACL
555 and wasting a lot of memory on those user records. It will also
556 force users to authenticate from scratch whenever their IP
560 Specifies the protection scope (aka realm name) which is to be
561 reported to the client for the authentication scheme. It is
562 commonly part of the text the user will see when prompted for
563 their username and password.
565 For Basic the default is "Squid proxy-caching web server".
566 For Digest there is no default, this parameter is mandatory.
567 For NTLM and Negotiate this parameter is ignored.
569 "children" numberofchildren [startup=N] [idle=N] [concurrency=N]
570 [queue-size=N] [on-persistent-overload=action]
572 The maximum number of authenticator processes to spawn. If
573 you start too few Squid will have to wait for them to process
574 a backlog of credential verifications, slowing it down. When
575 password verifications are done via a (slow) network you are
576 likely to need lots of authenticator processes.
578 The startup= and idle= options permit some skew in the exact
579 amount run. A minimum of startup=N will begin during startup
580 and reconfigure. Squid will start more in groups of up to
581 idle=N in an attempt to meet traffic needs and to keep idle=N
582 free above those traffic needs up to the maximum.
584 The concurrency= option sets the number of concurrent requests
585 the helper can process. The default of 0 is used for helpers
586 who only supports one request at a time. Setting this to a
587 number greater than 0 changes the protocol used to include a
588 channel ID field first on the request/response line, allowing
589 multiple requests to be sent to the same helper in parallel
590 without waiting for the response.
592 Concurrency must not be set unless it's known the helper
593 supports the input format with channel-ID fields.
595 The queue-size=N option sets the maximum number of queued
596 requests to N. The default maximum is 2*numberofchildren. Squid
597 is allowed to temporarily exceed the configured maximum, marking
598 the affected helper as "overloaded". If the helper overload
599 lasts more than 3 minutes, the action prescribed by the
600 on-persistent-overload option applies.
602 The on-persistent-overload=action option specifies Squid
603 reaction to a new helper request arriving when the helper
604 has been overloaded for more that 3 minutes already. The number
605 of queued requests determines whether the helper is overloaded
606 (see the queue-size option).
608 Two actions are supported:
610 die Squid worker quits. This is the default behavior.
612 ERR Squid treats the helper request as if it was
613 immediately submitted, and the helper immediately
614 replied with an ERR response. This action has no effect
615 on the already queued and in-progress helper requests.
617 NOTE: NTLM and Negotiate schemes do not support concurrency
618 in the Squid code module even though some helpers can.
621 If you experience problems with PUT/POST requests when using
622 the NTLM or Negotiate schemes then you can try setting this
623 to off. This will cause Squid to forcibly close the connection
624 on the initial request where the browser asks which schemes
625 are supported by the proxy.
627 For Basic and Digest this parameter is ignored.
630 HTTP uses iso-latin-1 as character set, while some
631 authentication backends such as LDAP expects UTF-8. If this is
632 set to on Squid will translate the HTTP iso-latin-1 charset to
633 UTF-8 before sending the username and password to the helper.
635 For NTLM and Negotiate this parameter is ignored.
637 IF HAVE_AUTH_MODULE_BASIC
638 === Basic authentication parameters ===
640 "credentialsttl" timetolive
641 Specifies how long squid assumes an externally validated
642 username:password pair is valid for - in other words how
643 often the helper program is called for that user. Set this
644 low to force revalidation with short lived passwords.
646 NOTE: setting this high does not impact your susceptibility
647 to replay attacks unless you are using an one-time password
648 system (such as SecureID). If you are using such a system,
649 you will be vulnerable to replay attacks unless you also
650 use the max_user_ip ACL in an http_access rule.
652 "casesensitive" on|off
653 Specifies if usernames are case sensitive. Most user databases
654 are case insensitive allowing the same username to be spelled
655 using both lower and upper case letters, but some are case
656 sensitive. This makes a big difference for user_max_ip ACL
657 processing and similar.
660 IF HAVE_AUTH_MODULE_DIGEST
661 === Digest authentication parameters ===
663 "nonce_garbage_interval" timeinterval
664 Specifies the interval that nonces that have been issued
665 to client_agent's are checked for validity.
667 "nonce_max_duration" timeinterval
668 Specifies the maximum length of time a given nonce will be
671 "nonce_max_count" number
672 Specifies the maximum number of times a given nonce can be
675 "nonce_strictness" on|off
676 Determines if squid requires strict increment-by-1 behavior
677 for nonce counts, or just incrementing (off - for use when
678 user agents generate nonce counts that occasionally miss 1
679 (ie, 1,2,4,6)). Default off.
681 "check_nonce_count" on|off
682 This directive if set to off can disable the nonce count check
683 completely to work around buggy digest qop implementations in
684 certain mainstream browser versions. Default on to check the
685 nonce count to protect from authentication replay attacks.
687 "post_workaround" on|off
688 This is a workaround to certain buggy browsers who send an
689 incorrect request digest in POST requests when reusing the
690 same nonce as acquired earlier on a GET request.
694 === Example Configuration ===
696 This configuration displays the recommended authentication scheme
697 order from most to least secure with recommended minimum configuration
698 settings for each scheme:
700 #auth_param negotiate program <uncomment and complete this line to activate>
701 #auth_param negotiate children 20 startup=0 idle=1
703 #auth_param digest program <uncomment and complete this line to activate>
704 #auth_param digest children 20 startup=0 idle=1
705 #auth_param digest realm Squid proxy-caching web server
706 #auth_param digest nonce_garbage_interval 5 minutes
707 #auth_param digest nonce_max_duration 30 minutes
708 #auth_param digest nonce_max_count 50
710 #auth_param ntlm program <uncomment and complete this line to activate>
711 #auth_param ntlm children 20 startup=0 idle=1
713 #auth_param basic program <uncomment and complete this line>
714 #auth_param basic children 5 startup=5 idle=1
715 #auth_param basic credentialsttl 2 hours
718 NAME: authenticate_cache_garbage_interval
722 LOC: Auth::TheConfig.garbageCollectInterval
724 The time period between garbage collection across the username cache.
725 This is a trade-off between memory utilization (long intervals - say
726 2 days) and CPU (short intervals - say 1 minute). Only change if you
730 NAME: authenticate_ttl
734 LOC: Auth::TheConfig.credentialsTtl
736 The time a user & their credentials stay in the logged in
737 user cache since their last request. When the garbage
738 interval passes, all user credentials that have passed their
739 TTL are removed from memory.
742 NAME: authenticate_ip_ttl
745 LOC: Auth::TheConfig.ipTtl
748 If you use proxy authentication and the 'max_user_ip' ACL,
749 this directive controls how long Squid remembers the IP
750 addresses associated with each user. Use a small value
751 (e.g., 60 seconds) if your users might change addresses
752 quickly, as is the case with dialup. You might be safe
753 using a larger value (e.g., 2 hours) in a corporate LAN
754 environment with relatively static address assignments.
759 -----------------------------------------------------------------------------
762 NAME: external_acl_type
763 TYPE: externalAclHelper
764 LOC: Config.externalAclHelperList
767 This option defines external acl classes using a helper program
768 to look up the status
770 external_acl_type name [options] FORMAT /path/to/helper [helper arguments]
774 ttl=n TTL in seconds for cached results (defaults to 3600
778 TTL for cached negative lookups (default same
781 grace=n Percentage remaining of TTL where a refresh of a
782 cached entry should be initiated without needing to
783 wait for a new reply. (default is for no grace period)
785 cache=n The maximum number of entries in the result cache. The
786 default limit is 262144 entries. Each cache entry usually
787 consumes at least 256 bytes. Squid currently does not remove
788 expired cache entries until the limit is reached, so a proxy
789 will sooner or later reach the limit. The expanded FORMAT
790 value is used as the cache key, so if the details in FORMAT
791 are highly variable, a larger cache may be needed to produce
792 reduction in helper load.
795 Maximum number of acl helper processes spawned to service
796 external acl lookups of this type. (default 5)
799 Minimum number of acl helper processes to spawn during
800 startup and reconfigure to service external acl lookups
801 of this type. (default 0)
804 Number of acl helper processes to keep ahead of traffic
805 loads. Squid will spawn this many at once whenever load
806 rises above the capabilities of existing processes.
807 Up to the value of children-max. (default 1)
809 concurrency=n concurrency level per process. Only used with helpers
810 capable of processing more than one query at a time.
812 queue-size=N The queue-size= option sets the maximum number of queued
813 requests. If the queued requests exceed queue size
815 The default value is set to 2*children-max.
817 protocol=2.5 Compatibility mode for Squid-2.5 external acl helpers.
819 ipv4 / ipv6 IP protocol used to communicate with this helper.
820 The default is to auto-detect IPv6 and use it when available.
823 FORMAT is a series of %macro codes. See logformat directive for a full list
824 of the accepted codes. Although note that at the time of any external ACL
825 being tested data may not be available and thus some %macro expand to '-'.
827 In addition to the logformat codes; when processing external ACLs these
828 additional macros are made available:
830 %ACL The name of the ACL being tested.
832 %DATA The ACL arguments specified in the referencing config
833 'acl ... external' line, separated by spaces (an
834 "argument string"). see acl external.
836 If there are no ACL arguments %DATA expands to '-'.
838 If you do not specify a DATA macro inside FORMAT,
839 Squid automatically appends %DATA to your FORMAT.
841 By default, Squid applies URL-encoding to each ACL
842 argument inside the argument string. If an explicit
843 encoding modifier is used (e.g., %#DATA), then Squid
844 encodes the whole argument string as a single token
845 (e.g., with %#DATA, spaces between arguments become
848 If SSL is enabled, the following formating codes become available:
850 %USER_CERT SSL User certificate in PEM format
851 %USER_CERTCHAIN SSL User certificate chain in PEM format
852 %USER_CERT_xx SSL User certificate subject attribute xx
853 %USER_CA_CERT_xx SSL User certificate issuer attribute xx
856 NOTE: all other format codes accepted by older Squid versions
860 General request syntax:
862 [channel-ID] FORMAT-values
865 FORMAT-values consists of transaction details expanded with
866 whitespace separation per the config file FORMAT specification
867 using the FORMAT macros listed above.
869 Request values sent to the helper are URL escaped to protect
870 each value in requests against whitespaces.
872 If using protocol=2.5 then the request sent to the helper is not
873 URL escaped to protect against whitespace.
875 NOTE: protocol=3.0 is deprecated as no longer necessary.
877 When using the concurrency= option the protocol is changed by
878 introducing a query channel tag in front of the request/response.
879 The query channel tag is a number between 0 and concurrency-1.
880 This value must be echoed back unchanged to Squid as the first part
881 of the response relating to its request.
884 The helper receives lines expanded per the above format specification
885 and for each input line returns 1 line starting with OK/ERR/BH result
886 code and optionally followed by additional keywords with more details.
889 General result syntax:
891 [channel-ID] result keyword=value ...
893 Result consists of one of the codes:
896 the ACL test produced a match.
899 the ACL test does not produce a match.
902 An internal error occurred in the helper, preventing
903 a result being identified.
905 The meaning of 'a match' is determined by your squid.conf
906 access control configuration. See the Squid wiki for details.
910 user= The users name (login)
912 password= The users password (for login= cache_peer option)
914 message= Message describing the reason for this response.
915 Available as %o in error pages.
916 Useful on (ERR and BH results).
918 tag= Apply a tag to a request. Only sets a tag once,
919 does not alter existing tags.
921 log= String to be logged in access.log. Available as
922 %ea in logformat specifications.
924 clt_conn_tag= Associates a TAG with the client TCP connection.
925 Please see url_rewrite_program related documentation
928 Any keywords may be sent on any response whether OK, ERR or BH.
930 All response keyword values need to be a single token with URL
931 escaping, or enclosed in double quotes (") and escaped using \ on
932 any double quotes or \ characters within the value. The wrapping
933 double quotes are removed before the value is interpreted by Squid.
934 \r and \n are also replace by CR and LF.
936 Some example key values:
940 user="J. \"Bob\" Smith"
947 DEFAULT: ssl::certHasExpired ssl_error X509_V_ERR_CERT_HAS_EXPIRED
948 DEFAULT: ssl::certNotYetValid ssl_error X509_V_ERR_CERT_NOT_YET_VALID
949 DEFAULT: ssl::certDomainMismatch ssl_error SQUID_X509_V_ERR_DOMAIN_MISMATCH
950 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
951 DEFAULT: ssl::certSelfSigned ssl_error X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT
954 DEFAULT: manager url_regex -i ^cache_object:// +i ^https?://[^/]+/squid-internal-mgr/
955 DEFAULT: localhost src 127.0.0.1/32 ::1
956 DEFAULT: to_localhost dst 127.0.0.0/8 0.0.0.0/32 ::1
957 DEFAULT: CONNECT method CONNECT
958 DEFAULT_DOC: ACLs all, manager, localhost, to_localhost, and CONNECT are predefined.
960 Defining an Access List
962 Every access list definition must begin with an aclname and acltype,
963 followed by either type-specific arguments or a quoted filename that
966 acl aclname acltype argument ...
967 acl aclname acltype "file" ...
969 When using "file", the file should contain one item per line.
974 Some acl types supports options which changes their default behaviour:
976 -i,+i By default, regular expressions are CASE-SENSITIVE. To make them
977 case-insensitive, use the -i option. To return case-sensitive
978 use the +i option between patterns, or make a new ACL line
981 -n Disable lookups and address type conversions. If lookup or
982 conversion is required because the parameter type (IP or
983 domain name) does not match the message address type (domain
984 name or IP), then the ACL would immediately declare a mismatch
985 without any warnings or lookups.
988 Perform a list membership test, interpreting values as
989 comma-separated token lists and matching against individual
990 tokens instead of whole values.
991 The optional "delimiters" parameter specifies one or more
992 alternative non-alphanumeric delimiter characters.
993 non-alphanumeric delimiter characters.
995 -- Used to stop processing all options, in the case the first acl
996 value has '-' character as first character (for example the '-'
997 is a valid domain name)
999 Some acl types require suspending the current request in order
1000 to access some external data source.
1001 Those which do are marked with the tag [slow], those which
1002 don't are marked as [fast].
1003 See http://wiki.squid-cache.org/SquidFaq/SquidAcl
1004 for further information
1006 ***** ACL TYPES AVAILABLE *****
1008 acl aclname src ip-address/mask ... # clients IP address [fast]
1009 acl aclname src addr1-addr2/mask ... # range of addresses [fast]
1010 acl aclname dst [-n] ip-address/mask ... # URL host's IP address [slow]
1011 acl aclname localip ip-address/mask ... # IP address the client connected to [fast]
1013 acl aclname arp mac-address ... (xx:xx:xx:xx:xx:xx notation)
1015 # The 'arp' ACL code is not portable to all operating systems.
1016 # It works on Linux, Solaris, Windows, FreeBSD, and some other
1019 # NOTE: Squid can only determine the MAC/EUI address for IPv4
1020 # clients that are on the same subnet. If the client is on a
1021 # different subnet, then Squid cannot find out its address.
1023 # NOTE 2: IPv6 protocol does not contain ARP. MAC/EUI is either
1024 # encoded directly in the IPv6 address or not available.
1026 acl aclname srcdomain .foo.com ...
1027 # reverse lookup, from client IP [slow]
1028 acl aclname dstdomain [-n] .foo.com ...
1029 # Destination server from URL [fast]
1030 acl aclname srcdom_regex [-i] \.foo\.com ...
1031 # regex matching client name [slow]
1032 acl aclname dstdom_regex [-n] [-i] \.foo\.com ...
1033 # regex matching server [fast]
1035 # For dstdomain and dstdom_regex a reverse lookup is tried if a IP
1036 # based URL is used and no match is found. The name "none" is used
1037 # if the reverse lookup fails.
1039 acl aclname src_as number ...
1040 acl aclname dst_as number ...
1042 # Except for access control, AS numbers can be used for
1043 # routing of requests to specific caches. Here's an
1044 # example for routing all requests for AS#1241 and only
1045 # those to mycache.mydomain.net:
1046 # acl asexample dst_as 1241
1047 # cache_peer_access mycache.mydomain.net allow asexample
1048 # cache_peer_access mycache_mydomain.net deny all
1050 acl aclname peername myPeer ...
1052 # match against a named cache_peer entry
1053 # set unique name= on cache_peer lines for reliable use.
1055 acl aclname time [day-abbrevs] [h1:m1-h2:m2]
1065 # h1:m1 must be less than h2:m2
1067 acl aclname url_regex [-i] ^http:// ...
1068 # regex matching on whole URL [fast]
1069 acl aclname urllogin [-i] [^a-zA-Z0-9] ...
1070 # regex matching on URL login field
1071 acl aclname urlpath_regex [-i] \.gif$ ...
1072 # regex matching on URL path [fast]
1074 acl aclname port 80 70 21 0-1024... # destination TCP port [fast]
1076 acl aclname localport 3128 ... # TCP port the client connected to [fast]
1077 # NP: for interception mode this is usually '80'
1079 acl aclname myportname 3128 ... # *_port name [fast]
1081 acl aclname proto HTTP FTP ... # request protocol [fast]
1083 acl aclname method GET POST ... # HTTP request method [fast]
1085 acl aclname http_status 200 301 500- 400-403 ...
1086 # status code in reply [fast]
1088 acl aclname browser [-i] regexp ...
1089 # pattern match on User-Agent header (see also req_header below) [fast]
1091 acl aclname referer_regex [-i] regexp ...
1092 # pattern match on Referer header [fast]
1093 # Referer is highly unreliable, so use with care
1095 acl aclname ident username ...
1096 acl aclname ident_regex [-i] pattern ...
1097 # string match on ident output [slow]
1098 # use REQUIRED to accept any non-null ident.
1100 acl aclname proxy_auth [-i] username ...
1101 acl aclname proxy_auth_regex [-i] pattern ...
1102 # perform http authentication challenge to the client and match against
1103 # supplied credentials [slow]
1105 # takes a list of allowed usernames.
1106 # use REQUIRED to accept any valid username.
1108 # Will use proxy authentication in forward-proxy scenarios, and plain
1109 # http authenticaiton in reverse-proxy scenarios
1111 # NOTE: when a Proxy-Authentication header is sent but it is not
1112 # needed during ACL checking the username is NOT logged
1115 # NOTE: proxy_auth requires a EXTERNAL authentication program
1116 # to check username/password combinations (see
1117 # auth_param directive).
1119 # NOTE: proxy_auth can't be used in a transparent/intercepting proxy
1120 # as the browser needs to be configured for using a proxy in order
1121 # to respond to proxy authentication.
1123 acl aclname snmp_community string ...
1124 # A community string to limit access to your SNMP Agent [fast]
1127 # acl snmppublic snmp_community public
1129 acl aclname maxconn number
1130 # This will be matched when the client's IP address has
1131 # more than <number> TCP connections established. [fast]
1132 # NOTE: This only measures direct TCP links so X-Forwarded-For
1133 # indirect clients are not counted.
1135 acl aclname max_user_ip [-s] number
1136 # This will be matched when the user attempts to log in from more
1137 # than <number> different ip addresses. The authenticate_ip_ttl
1138 # parameter controls the timeout on the ip entries. [fast]
1139 # If -s is specified the limit is strict, denying browsing
1140 # from any further IP addresses until the ttl has expired. Without
1141 # -s Squid will just annoy the user by "randomly" denying requests.
1142 # (the counter is reset each time the limit is reached and a
1143 # request is denied)
1144 # NOTE: in acceleration mode or where there is mesh of child proxies,
1145 # clients may appear to come from multiple addresses if they are
1146 # going through proxy farms, so a limit of 1 may cause user problems.
1148 acl aclname random probability
1149 # Pseudo-randomly match requests. Based on the probability given.
1150 # Probability may be written as a decimal (0.333), fraction (1/3)
1151 # or ratio of matches:non-matches (3:5).
1153 acl aclname req_mime_type [-i] mime-type ...
1154 # regex match against the mime type of the request generated
1155 # by the client. Can be used to detect file upload or some
1156 # types HTTP tunneling requests [fast]
1157 # NOTE: This does NOT match the reply. You cannot use this
1158 # to match the returned file type.
1160 acl aclname req_header header-name [-i] any\.regex\.here
1161 # regex match against any of the known request headers. May be
1162 # thought of as a superset of "browser", "referer" and "mime-type"
1165 acl aclname rep_mime_type [-i] mime-type ...
1166 # regex match against the mime type of the reply received by
1167 # squid. Can be used to detect file download or some
1168 # types HTTP tunneling requests. [fast]
1169 # NOTE: This has no effect in http_access rules. It only has
1170 # effect in rules that affect the reply data stream such as
1171 # http_reply_access.
1173 acl aclname rep_header header-name [-i] any\.regex\.here
1174 # regex match against any of the known reply headers. May be
1175 # thought of as a superset of "browser", "referer" and "mime-type"
1178 acl aclname external class_name [arguments...]
1179 # external ACL lookup via a helper class defined by the
1180 # external_acl_type directive [slow]
1182 acl aclname user_cert attribute values...
1183 # match against attributes in a user SSL certificate
1184 # attribute is one of DN/C/O/CN/L/ST or a numerical OID [fast]
1186 acl aclname ca_cert attribute values...
1187 # match against attributes a users issuing CA SSL certificate
1188 # attribute is one of DN/C/O/CN/L/ST or a numerical OID [fast]
1190 acl aclname ext_user username ...
1191 acl aclname ext_user_regex [-i] pattern ...
1192 # string match on username returned by external acl helper [slow]
1193 # use REQUIRED to accept any non-null user name.
1195 acl aclname tag tagvalue ...
1196 # string match on tag returned by external acl helper [fast]
1197 # DEPRECATED. Only the first tag will match with this ACL.
1198 # Use the 'note' ACL instead for handling multiple tag values.
1200 acl aclname hier_code codename ...
1201 # string match against squid hierarchy code(s); [fast]
1202 # e.g., DIRECT, PARENT_HIT, NONE, etc.
1204 # NOTE: This has no effect in http_access rules. It only has
1205 # effect in rules that affect the reply data stream such as
1206 # http_reply_access.
1208 acl aclname note [-m[=delimiters]] name [value ...]
1209 # match transaction annotation [fast]
1210 # Without values, matches any annotation with a given name.
1211 # With value(s), matches any annotation with a given name that
1212 # also has one of the given values.
1213 # If the -m flag is used, then the value of the named
1214 # annotation is interpreted as a list of tokens, and the ACL
1215 # matches individual name=token pairs rather than whole
1216 # name=value pairs. See "ACL Options" above for more info.
1217 # Annotation sources include note and adaptation_meta directives
1218 # as well as helper and eCAP responses.
1220 acl aclname adaptation_service service ...
1221 # Matches the name of any icap_service, ecap_service,
1222 # adaptation_service_set, or adaptation_service_chain that Squid
1223 # has used (or attempted to use) for the master transaction.
1224 # This ACL must be defined after the corresponding adaptation
1225 # service is named in squid.conf. This ACL is usable with
1226 # adaptation_meta because it starts matching immediately after
1227 # the service has been selected for adaptation.
1230 acl aclname ssl_error errorname
1231 # match against SSL certificate validation error [fast]
1233 # For valid error names see in @DEFAULT_ERROR_DIR@/templates/error-details.txt
1236 # The following can be used as shortcuts for certificate properties:
1237 # [ssl::]certHasExpired: the "not after" field is in the past
1238 # [ssl::]certNotYetValid: the "not before" field is in the future
1239 # [ssl::]certUntrusted: The certificate issuer is not to be trusted.
1240 # [ssl::]certSelfSigned: The certificate is self signed.
1241 # [ssl::]certDomainMismatch: The certificate CN domain does not
1242 # match the name the name of the host we are connecting to.
1244 # The ssl::certHasExpired, ssl::certNotYetValid, ssl::certDomainMismatch,
1245 # ssl::certUntrusted, and ssl::certSelfSigned can also be used as
1246 # predefined ACLs, just like the 'all' ACL.
1248 # NOTE: The ssl_error ACL is only supported with sslproxy_cert_error,
1249 # sslproxy_cert_sign, and sslproxy_cert_adapt options.
1251 acl aclname server_cert_fingerprint [-sha1] fingerprint
1252 # match against server SSL certificate fingerprint [fast]
1254 # The fingerprint is the digest of the DER encoded version
1255 # of the whole certificate. The user should use the form: XX:XX:...
1256 # Optional argument specifies the digest algorithm to use.
1257 # The SHA1 digest algorithm is the default and is currently
1258 # the only algorithm supported (-sha1).
1260 acl aclname at_step step
1261 # match against the current step during ssl_bump evaluation [fast]
1262 # Never matches and should not be used outside the ssl_bump context.
1264 # At each SslBump step, Squid evaluates ssl_bump directives to find
1265 # the next bumping action (e.g., peek or splice). Valid SslBump step
1266 # values and the corresponding ssl_bump evaluation moments are:
1267 # SslBump1: After getting TCP-level and HTTP CONNECT info.
1268 # SslBump2: After getting SSL Client Hello info.
1269 # SslBump3: After getting SSL Server Hello info.
1271 acl aclname ssl::server_name .foo.com ...
1272 # matches server name obtained from various sources [fast]
1274 # The server name is obtained during Ssl-Bump steps from such sources
1275 # as CONNECT request URI, client SNI, and SSL server certificate CN.
1276 # During each Ssl-Bump step, Squid may improve its understanding of a
1277 # "true server name". Unlike dstdomain, this ACL does not perform
1279 # The "none" name can be used to match transactions where Squid
1280 # could not compute the server name using any information source
1281 # already available at the ACL evaluation time.
1283 acl aclname ssl::server_name_regex [-i] \.foo\.com ...
1284 # regex matches server name obtained from various sources [fast]
1286 acl aclname connections_encrypted
1287 # matches transactions with all HTTP messages received over TLS
1288 # transport connections. [fast]
1290 # The master transaction deals with HTTP messages received from
1291 # various sources. All sources used by the master transaction in the
1292 # past are considered by the ACL. The following rules define whether
1293 # a given message source taints the entire master transaction,
1294 # resulting in ACL mismatches:
1296 # * The HTTP client transport connection is not TLS.
1297 # * An adaptation service connection-encryption flag is off.
1298 # * The peer or origin server transport connection is not TLS.
1300 # Caching currently does not affect these rules. This cache ignorance
1301 # implies that only the current HTTP client transport and REQMOD
1302 # services status determine whether this ACL matches a from-cache
1303 # transaction. The source of the cached response does not have any
1304 # effect on future transaction that use the cached response without
1305 # revalidation. This may change.
1307 # DNS, ICP, and HTCP exchanges during the master transaction do not
1308 # affect these rules.
1310 acl aclname any-of acl1 acl2 ...
1311 # match any one of the acls [fast or slow]
1312 # The first matching ACL stops further ACL evaluation.
1314 # ACLs from multiple any-of lines with the same name are ORed.
1315 # For example, A = (a1 or a2) or (a3 or a4) can be written as
1316 # acl A any-of a1 a2
1317 # acl A any-of a3 a4
1319 # This group ACL is fast if all evaluated ACLs in the group are fast
1320 # and slow otherwise.
1322 acl aclname all-of acl1 acl2 ...
1323 # match all of the acls [fast or slow]
1324 # The first mismatching ACL stops further ACL evaluation.
1326 # ACLs from multiple all-of lines with the same name are ORed.
1327 # For example, B = (b1 and b2) or (b3 and b4) can be written as
1328 # acl B all-of b1 b2
1329 # acl B all-of b3 b4
1331 # This group ACL is fast if all evaluated ACLs in the group are fast
1332 # and slow otherwise.
1335 acl macaddress arp 09:00:2b:23:45:67
1336 acl myexample dst_as 1241
1337 acl password proxy_auth REQUIRED
1338 acl fileupload req_mime_type -i ^multipart/form-data$
1339 acl javascript rep_mime_type -i ^application/x-javascript$
1343 # Recommended minimum configuration:
1346 # Example rule allowing access from your local networks.
1347 # Adapt to list your (internal) IP networks from where browsing
1349 acl localnet src 0.0.0.1-0.255.255.255 # RFC 1122 "this" network (LAN)
1350 acl localnet src 10.0.0.0/8 # RFC 1918 local private network (LAN)
1351 acl localnet src 100.64.0.0/10 # RFC 6598 shared address space (CGN)
1352 acl localhet src 169.254.0.0/16 # RFC 3927 link-local (directly plugged) machines
1353 acl localnet src 172.16.0.0/12 # RFC 1918 local private network (LAN)
1354 acl localnet src 192.168.0.0/16 # RFC 1918 local private network (LAN)
1355 acl localnet src fc00::/7 # RFC 4193 local private network range
1356 acl localnet src fe80::/10 # RFC 4291 link-local (directly plugged) machines
1358 acl SSL_ports port 443
1359 acl Safe_ports port 80 # http
1360 acl Safe_ports port 21 # ftp
1361 acl Safe_ports port 443 # https
1362 acl Safe_ports port 70 # gopher
1363 acl Safe_ports port 210 # wais
1364 acl Safe_ports port 1025-65535 # unregistered ports
1365 acl Safe_ports port 280 # http-mgmt
1366 acl Safe_ports port 488 # gss-http
1367 acl Safe_ports port 591 # filemaker
1368 acl Safe_ports port 777 # multiling http
1372 NAME: proxy_protocol_access
1374 LOC: Config.accessList.proxyProtocol
1376 DEFAULT_DOC: all TCP connections to ports with require-proxy-header will be denied
1378 Determine which client proxies can be trusted to provide correct
1379 information regarding real client IP address using PROXY protocol.
1381 Requests may pass through a chain of several other proxies
1382 before reaching us. The original source details may by sent in:
1383 * HTTP message Forwarded header, or
1384 * HTTP message X-Forwarded-For header, or
1385 * PROXY protocol connection header.
1387 This directive is solely for validating new PROXY protocol
1388 connections received from a port flagged with require-proxy-header.
1389 It is checked only once after TCP connection setup.
1391 A deny match results in TCP connection closure.
1393 An allow match is required for Squid to permit the corresponding
1394 TCP connection, before Squid even looks for HTTP request headers.
1395 If there is an allow match, Squid starts using PROXY header information
1396 to determine the source address of the connection for all future ACL
1397 checks, logging, etc.
1399 SECURITY CONSIDERATIONS:
1401 Any host from which we accept client IP details can place
1402 incorrect information in the relevant header, and Squid
1403 will use the incorrect information as if it were the
1404 source address of the request. This may enable remote
1405 hosts to bypass any access control restrictions that are
1406 based on the client's source addresses.
1408 This clause only supports fast acl types.
1409 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1412 NAME: follow_x_forwarded_for
1414 IFDEF: FOLLOW_X_FORWARDED_FOR
1415 LOC: Config.accessList.followXFF
1416 DEFAULT_IF_NONE: deny all
1417 DEFAULT_DOC: X-Forwarded-For header will be ignored.
1419 Determine which client proxies can be trusted to provide correct
1420 information regarding real client IP address.
1422 Requests may pass through a chain of several other proxies
1423 before reaching us. The original source details may by sent in:
1424 * HTTP message Forwarded header, or
1425 * HTTP message X-Forwarded-For header, or
1426 * PROXY protocol connection header.
1428 PROXY protocol connections are controlled by the proxy_protocol_access
1429 directive which is checked before this.
1431 If a request reaches us from a source that is allowed by this
1432 directive, then we trust the information it provides regarding
1433 the IP of the client it received from (if any).
1435 For the purpose of ACLs used in this directive the src ACL type always
1436 matches the address we are testing and srcdomain matches its rDNS.
1438 On each HTTP request Squid checks for X-Forwarded-For header fields.
1439 If found the header values are iterated in reverse order and an allow
1440 match is required for Squid to continue on to the next value.
1441 The verification ends when a value receives a deny match, cannot be
1442 tested, or there are no more values to test.
1443 NOTE: Squid does not yet follow the Forwarded HTTP header.
1445 The end result of this process is an IP address that we will
1446 refer to as the indirect client address. This address may
1447 be treated as the client address for access control, ICAP, delay
1448 pools and logging, depending on the acl_uses_indirect_client,
1449 icap_uses_indirect_client, delay_pool_uses_indirect_client,
1450 log_uses_indirect_client and tproxy_uses_indirect_client options.
1452 This clause only supports fast acl types.
1453 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1455 SECURITY CONSIDERATIONS:
1457 Any host from which we accept client IP details can place
1458 incorrect information in the relevant header, and Squid
1459 will use the incorrect information as if it were the
1460 source address of the request. This may enable remote
1461 hosts to bypass any access control restrictions that are
1462 based on the client's source addresses.
1466 acl localhost src 127.0.0.1
1467 acl my_other_proxy srcdomain .proxy.example.com
1468 follow_x_forwarded_for allow localhost
1469 follow_x_forwarded_for allow my_other_proxy
1472 NAME: acl_uses_indirect_client
1475 IFDEF: FOLLOW_X_FORWARDED_FOR
1477 LOC: Config.onoff.acl_uses_indirect_client
1479 Controls whether the indirect client address
1480 (see follow_x_forwarded_for) is used instead of the
1481 direct client address in acl matching.
1483 NOTE: maxconn ACL considers direct TCP links and indirect
1484 clients will always have zero. So no match.
1487 NAME: delay_pool_uses_indirect_client
1490 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_DELAY_POOLS
1492 LOC: Config.onoff.delay_pool_uses_indirect_client
1494 Controls whether the indirect client address
1495 (see follow_x_forwarded_for) is used instead of the
1496 direct client address in delay pools.
1499 NAME: log_uses_indirect_client
1502 IFDEF: FOLLOW_X_FORWARDED_FOR
1504 LOC: Config.onoff.log_uses_indirect_client
1506 Controls whether the indirect client address
1507 (see follow_x_forwarded_for) is used instead of the
1508 direct client address in the access log.
1511 NAME: tproxy_uses_indirect_client
1514 IFDEF: FOLLOW_X_FORWARDED_FOR&&LINUX_NETFILTER
1516 LOC: Config.onoff.tproxy_uses_indirect_client
1518 Controls whether the indirect client address
1519 (see follow_x_forwarded_for) is used instead of the
1520 direct client address when spoofing the outgoing client.
1522 This has no effect on requests arriving in non-tproxy
1525 SECURITY WARNING: Usage of this option is dangerous
1526 and should not be used trivially. Correct configuration
1527 of follow_x_forwarded_for with a limited set of trusted
1528 sources is required to prevent abuse of your proxy.
1531 NAME: spoof_client_ip
1533 LOC: Config.accessList.spoof_client_ip
1535 DEFAULT_DOC: Allow spoofing on all TPROXY traffic.
1537 Control client IP address spoofing of TPROXY traffic based on
1538 defined access lists.
1540 spoof_client_ip allow|deny [!]aclname ...
1542 If there are no "spoof_client_ip" lines present, the default
1543 is to "allow" spoofing of any suitable request.
1545 Note that the cache_peer "no-tproxy" option overrides this ACL.
1547 This clause supports fast acl types.
1548 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1553 LOC: Config.accessList.http
1554 DEFAULT_IF_NONE: deny all
1555 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1557 Allowing or Denying access based on defined access lists
1559 To allow or deny a message received on an HTTP, HTTPS, or FTP port:
1560 http_access allow|deny [!]aclname ...
1562 NOTE on default values:
1564 If there are no "access" lines present, the default is to deny
1567 If none of the "access" lines cause a match, the default is the
1568 opposite of the last line in the list. If the last line was
1569 deny, the default is allow. Conversely, if the last line
1570 is allow, the default will be deny. For these reasons, it is a
1571 good idea to have an "deny all" entry at the end of your access
1572 lists to avoid potential confusion.
1574 This clause supports both fast and slow acl types.
1575 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1580 # Recommended minimum Access Permission configuration:
1582 # Deny requests to certain unsafe ports
1583 http_access deny !Safe_ports
1585 # Deny CONNECT to other than secure SSL ports
1586 http_access deny CONNECT !SSL_ports
1588 # Only allow cachemgr access from localhost
1589 http_access allow localhost manager
1590 http_access deny manager
1592 # We strongly recommend the following be uncommented to protect innocent
1593 # web applications running on the proxy server who think the only
1594 # one who can access services on "localhost" is a local user
1595 #http_access deny to_localhost
1598 # INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS
1601 # Example rule allowing access from your local networks.
1602 # Adapt localnet in the ACL section to list your (internal) IP networks
1603 # from where browsing should be allowed
1604 http_access allow localnet
1605 http_access allow localhost
1607 # And finally deny all other access to this proxy
1608 http_access deny all
1612 NAME: adapted_http_access http_access2
1614 LOC: Config.accessList.adapted_http
1616 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1618 Allowing or Denying access based on defined access lists
1620 Essentially identical to http_access, but runs after redirectors
1621 and ICAP/eCAP adaptation. Allowing access control based on their
1624 If not set then only http_access is used.
1627 NAME: http_reply_access
1629 LOC: Config.accessList.reply
1631 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1633 Allow replies to client requests. This is complementary to http_access.
1635 http_reply_access allow|deny [!] aclname ...
1637 NOTE: if there are no access lines present, the default is to allow
1640 If none of the access lines cause a match the opposite of the
1641 last line will apply. Thus it is good practice to end the rules
1642 with an "allow all" or "deny all" entry.
1644 This clause supports both fast and slow acl types.
1645 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1650 LOC: Config.accessList.icp
1652 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1654 Allowing or Denying access to the ICP port based on defined
1657 icp_access allow|deny [!]aclname ...
1659 NOTE: The default if no icp_access lines are present is to
1660 deny all traffic. This default may cause problems with peers
1663 This clause only supports fast acl types.
1664 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1666 # Allow ICP queries from local networks only
1667 #icp_access allow localnet
1668 #icp_access deny all
1674 LOC: Config.accessList.htcp
1676 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1678 Allowing or Denying access to the HTCP port based on defined
1681 htcp_access allow|deny [!]aclname ...
1683 See also htcp_clr_access for details on access control for
1684 cache purge (CLR) HTCP messages.
1686 NOTE: The default if no htcp_access lines are present is to
1687 deny all traffic. This default may cause problems with peers
1688 using the htcp option.
1690 This clause only supports fast acl types.
1691 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1693 # Allow HTCP queries from local networks only
1694 #htcp_access allow localnet
1695 #htcp_access deny all
1698 NAME: htcp_clr_access
1701 LOC: Config.accessList.htcp_clr
1703 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1705 Allowing or Denying access to purge content using HTCP based
1706 on defined access lists.
1707 See htcp_access for details on general HTCP access control.
1709 htcp_clr_access allow|deny [!]aclname ...
1711 This clause only supports fast acl types.
1712 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1714 # Allow HTCP CLR requests from trusted peers
1715 acl htcp_clr_peer src 192.0.2.2 2001:DB8::2
1716 htcp_clr_access allow htcp_clr_peer
1717 htcp_clr_access deny all
1722 LOC: Config.accessList.miss
1724 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1726 Determines whether network access is permitted when satisfying a request.
1729 to force your neighbors to use you as a sibling instead of
1732 acl localclients src 192.0.2.0/24 2001:DB8::a:0/64
1733 miss_access deny !localclients
1734 miss_access allow all
1736 This means only your local clients are allowed to fetch relayed/MISS
1737 replies from the network and all other clients can only fetch cached
1740 The default for this setting allows all clients who passed the
1741 http_access rules to relay via this proxy.
1743 This clause only supports fast acl types.
1744 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1747 NAME: ident_lookup_access
1751 DEFAULT_DOC: Unless rules exist in squid.conf, IDENT is not fetched.
1752 LOC: Ident::TheConfig.identLookup
1754 A list of ACL elements which, if matched, cause an ident
1755 (RFC 931) lookup to be performed for this request. For
1756 example, you might choose to always perform ident lookups
1757 for your main multi-user Unix boxes, but not for your Macs
1758 and PCs. By default, ident lookups are not performed for
1761 To enable ident lookups for specific client addresses, you
1762 can follow this example:
1764 acl ident_aware_hosts src 198.168.1.0/24
1765 ident_lookup_access allow ident_aware_hosts
1766 ident_lookup_access deny all
1768 Only src type ACL checks are fully supported. A srcdomain
1769 ACL might work at times, but it will not always provide
1772 This clause only supports fast acl types.
1773 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1776 NAME: reply_body_max_size
1777 COMMENT: size [acl acl...]
1780 DEFAULT_DOC: No limit is applied.
1781 LOC: Config.ReplyBodySize
1783 This option specifies the maximum size of a reply body. It can be
1784 used to prevent users from downloading very large files, such as
1785 MP3's and movies. When the reply headers are received, the
1786 reply_body_max_size lines are processed, and the first line where
1787 all (if any) listed ACLs are true is used as the maximum body size
1790 This size is checked twice. First when we get the reply headers,
1791 we check the content-length value. If the content length value exists
1792 and is larger than the allowed size, the request is denied and the
1793 user receives an error message that says "the request or reply
1794 is too large." If there is no content-length, and the reply
1795 size exceeds this limit, the client's connection is just closed
1796 and they will receive a partial reply.
1798 WARNING: downstream caches probably can not detect a partial reply
1799 if there is no content-length header, so they will cache
1800 partial responses and give them out as hits. You should NOT
1801 use this option if you have downstream caches.
1803 WARNING: A maximum size smaller than the size of squid's error messages
1804 will cause an infinite loop and crash squid. Ensure that the smallest
1805 non-zero value you use is greater that the maximum header size plus
1806 the size of your largest error page.
1808 If you set this parameter none (the default), there will be
1811 Configuration Format is:
1812 reply_body_max_size SIZE UNITS [acl ...]
1814 reply_body_max_size 10 MB
1818 NAME: on_unsupported_protocol
1819 TYPE: on_unsupported_protocol
1820 LOC: Config.accessList.on_unsupported_protocol
1822 DEFAULT_DOC: Respond with an error message to unidentifiable traffic
1824 Determines Squid behavior when encountering strange requests at the
1825 beginning of an accepted TCP connection or the beginning of a bumped
1826 CONNECT tunnel. Controlling Squid reaction to unexpected traffic is
1827 especially useful in interception environments where Squid is likely
1828 to see connections for unsupported protocols that Squid should either
1829 terminate or tunnel at TCP level.
1831 on_unsupported_protocol <action> [!]acl ...
1833 The first matching action wins. Only fast ACLs are supported.
1835 Supported actions are:
1837 tunnel: Establish a TCP connection with the intended server and
1838 blindly shovel TCP packets between the client and server.
1840 respond: Respond with an error message, using the transfer protocol
1841 for the Squid port that received the request (e.g., HTTP
1842 for connections intercepted at the http_port). This is the
1845 Squid expects the following traffic patterns:
1847 http_port: a plain HTTP request
1848 https_port: SSL/TLS handshake followed by an [encrypted] HTTP request
1849 ftp_port: a plain FTP command (no on_unsupported_protocol support yet!)
1850 CONNECT tunnel on http_port: same as https_port
1851 CONNECT tunnel on https_port: same as https_port
1853 Currently, this directive has effect on intercepted connections and
1854 bumped tunnels only. Other cases are not supported because Squid
1855 cannot know the intended destination of other traffic.
1858 # define what Squid errors indicate receiving non-HTTP traffic:
1859 acl foreignProtocol squid_error ERR_PROTOCOL_UNKNOWN ERR_TOO_BIG
1860 # define what Squid errors indicate receiving nothing:
1861 acl serverTalksFirstProtocol squid_error ERR_REQUEST_START_TIMEOUT
1862 # tunnel everything that does not look like HTTP:
1863 on_unsupported_protocol tunnel foreignProtocol
1864 # tunnel if we think the client waits for the server to talk first:
1865 on_unsupported_protocol tunnel serverTalksFirstProtocol
1866 # in all other error cases, just send an HTTP "error page" response:
1867 on_unsupported_protocol respond all
1869 See also: squid_error ACL
1875 LOC: Auth::TheConfig.schemeAccess
1877 DEFAULT_DOC: use all auth_param schemes in their configuration order
1879 Use this directive to customize authentication schemes presence and
1880 order in Squid's Unauthorized and Authentication Required responses.
1882 auth_schemes scheme1,scheme2,... [!]aclname ...
1884 where schemeN is the name of one of the authentication schemes
1885 configured using auth_param directives. At least one scheme name is
1886 required. Multiple scheme names are separated by commas. Either
1887 avoid whitespace or quote the entire schemes list.
1889 A special "ALL" scheme name expands to all auth_param-configured
1890 schemes in their configuration order. This directive cannot be used
1891 to configure Squid to offer no authentication schemes at all.
1893 The first matching auth_schemes rule determines the schemes order
1894 for the current Authentication Required transaction. Note that the
1895 future response is not yet available during auth_schemes evaluation.
1897 If this directive is not used or none of its rules match, then Squid
1898 responds with all configured authentication schemes in the order of
1899 auth_param directives in the configuration file.
1901 This directive does not determine when authentication is used or
1902 how each authentication scheme authenticates clients.
1904 The following example sends basic and negotiate authentication
1905 schemes, in that order, when requesting authentication of HTTP
1906 requests matching the isIE ACL (not shown) while sending all
1907 auth_param schemes in their configuration order to other clients:
1909 auth_schemes basic,negotiate isIE
1910 auth_schemes ALL all # explicit default
1912 This directive supports fast ACLs only.
1914 See also: auth_param.
1919 -----------------------------------------------------------------------------
1922 NAME: http_port ascii_port
1927 Usage: port [mode] [options]
1928 hostname:port [mode] [options]
1929 1.2.3.4:port [mode] [options]
1931 The socket addresses where Squid will listen for HTTP client
1932 requests. You may specify multiple socket addresses.
1933 There are three forms: port alone, hostname with port, and
1934 IP address with port. If you specify a hostname or IP
1935 address, Squid binds the socket to that specific
1936 address. Most likely, you do not need to bind to a specific
1937 address, so you can use the port number alone.
1939 If you are running Squid in accelerator mode, you
1940 probably want to listen on port 80 also, or instead.
1942 The -a command line option may be used to specify additional
1943 port(s) where Squid listens for proxy request. Such ports will
1944 be plain proxy ports with no options.
1946 You may specify multiple socket addresses on multiple lines.
1950 intercept Support for IP-Layer NAT interception delivering
1951 traffic to this Squid port.
1952 NP: disables authentication on the port.
1954 tproxy Support Linux TPROXY (or BSD divert-to) with spoofing
1955 of outgoing connections using the client IP address.
1956 NP: disables authentication on the port.
1958 accel Accelerator / reverse proxy mode
1960 ssl-bump For each CONNECT request allowed by ssl_bump ACLs,
1961 establish secure connection with the client and with
1962 the server, decrypt HTTPS messages as they pass through
1963 Squid, and treat them as unencrypted HTTP messages,
1964 becoming the man-in-the-middle.
1966 The ssl_bump option is required to fully enable
1967 bumping of CONNECT requests.
1969 Omitting the mode flag causes default forward proxy mode to be used.
1972 Accelerator Mode Options:
1974 defaultsite=domainname
1975 What to use for the Host: header if it is not present
1976 in a request. Determines what site (not origin server)
1977 accelerators should consider the default.
1979 no-vhost Disable using HTTP/1.1 Host header for virtual domain support.
1981 protocol= Protocol to reconstruct accelerated and intercepted
1982 requests with. Defaults to HTTP/1.1 for http_port and
1983 HTTPS/1.1 for https_port.
1984 When an unsupported value is configured Squid will
1985 produce a FATAL error.
1986 Values: HTTP or HTTP/1.1, HTTPS or HTTPS/1.1
1988 vport Virtual host port support. Using the http_port number
1989 instead of the port passed on Host: headers.
1991 vport=NN Virtual host port support. Using the specified port
1992 number instead of the port passed on Host: headers.
1995 Act as if this Squid is the origin server.
1996 This currently means generate new Date: and Expires:
1997 headers on HIT instead of adding Age:.
1999 ignore-cc Ignore request Cache-Control headers.
2001 WARNING: This option violates HTTP specifications if
2002 used in non-accelerator setups.
2004 allow-direct Allow direct forwarding in accelerator mode. Normally
2005 accelerated requests are denied direct forwarding as if
2006 never_direct was used.
2008 WARNING: this option opens accelerator mode to security
2009 vulnerabilities usually only affecting in interception
2010 mode. Make sure to protect forwarding with suitable
2011 http_access rules when using this.
2014 SSL Bump Mode Options:
2015 In addition to these options ssl-bump requires TLS/SSL options.
2017 generate-host-certificates[=<on|off>]
2018 Dynamically create SSL server certificates for the
2019 destination hosts of bumped CONNECT requests.When
2020 enabled, the cert and key options are used to sign
2021 generated certificates. Otherwise generated
2022 certificate will be selfsigned.
2023 If there is a CA certificate lifetime of the generated
2024 certificate equals lifetime of the CA certificate. If
2025 generated certificate is selfsigned lifetime is three
2027 This option is enabled by default when ssl-bump is used.
2028 See the ssl-bump option above for more information.
2030 dynamic_cert_mem_cache_size=SIZE
2031 Approximate total RAM size spent on cached generated
2032 certificates. If set to zero, caching is disabled. The
2033 default value is 4MB.
2037 cert= Path to SSL certificate (PEM format).
2039 key= Path to SSL private key file (PEM format)
2040 if not specified, the certificate file is
2041 assumed to be a combined certificate and
2044 cipher= Colon separated list of supported ciphers.
2045 NOTE: some ciphers such as EDH ciphers depend on
2046 additional settings. If those settings are
2047 omitted the ciphers may be silently ignored
2048 by the OpenSSL library.
2050 options= Various SSL implementation options. The most important
2053 NO_SSLv3 Disallow the use of SSLv3
2055 NO_TLSv1 Disallow the use of TLSv1.0
2057 NO_TLSv1_1 Disallow the use of TLSv1.1
2059 NO_TLSv1_2 Disallow the use of TLSv1.2
2062 Always create a new key when using
2063 temporary/ephemeral DH key exchanges
2066 Enable ephemeral ECDH key exchange.
2067 The adopted curve should be specified
2068 using the tls-dh option.
2071 Disable use of RFC5077 session tickets.
2072 Some servers may have problems
2073 understanding the TLS extension due
2074 to ambiguous specification in RFC4507.
2076 ALL Enable various bug workarounds
2077 suggested as "harmless" by OpenSSL
2078 Be warned that this reduces SSL/TLS
2079 strength to some attacks.
2081 See the OpenSSL SSL_CTX_set_options documentation for a
2084 clientca= File containing the list of CAs to use when
2085 requesting a client certificate.
2087 tls-cafile= PEM file containing CA certificates to use when verifying
2088 client certificates. If not configured clientca will be
2089 used. May be repeated to load multiple files.
2091 capath= Directory containing additional CA certificates
2092 and CRL lists to use when verifying client certificates.
2093 Requires OpenSSL or LibreSSL.
2095 crlfile= File of additional CRL lists to use when verifying
2096 the client certificate, in addition to CRLs stored in
2097 the capath. Implies VERIFY_CRL flag below.
2100 File containing DH parameters for temporary/ephemeral DH key
2101 exchanges, optionally prefixed by a curve for ephemeral ECDH
2103 See OpenSSL documentation for details on how to create the
2104 DH parameter file. Supported curves for ECDH can be listed
2105 using the "openssl ecparam -list_curves" command.
2106 WARNING: EDH and EECDH ciphers will be silently disabled if
2107 this option is not set.
2109 sslflags= Various flags modifying the use of SSL:
2111 Don't request client certificates
2112 immediately, but wait until acl processing
2113 requires a certificate (not yet implemented).
2115 Don't allow for session reuse. Each connection
2116 will result in a new SSL session.
2118 Verify CRL lists when accepting client
2121 Verify CRL lists for all certificates in the
2122 client certificate chain.
2124 tls-default-ca[=off]
2125 Whether to use the system Trusted CAs. Default is OFF.
2127 tls-no-npn Do not use the TLS NPN extension to advertise HTTP/1.1.
2129 sslcontext= SSL session ID context identifier.
2133 connection-auth[=on|off]
2134 use connection-auth=off to tell Squid to prevent
2135 forwarding Microsoft connection oriented authentication
2136 (NTLM, Negotiate and Kerberos)
2138 disable-pmtu-discovery=
2139 Control Path-MTU discovery usage:
2140 off lets OS decide on what to do (default).
2141 transparent disable PMTU discovery when transparent
2143 always disable always PMTU discovery.
2145 In many setups of transparently intercepting proxies
2146 Path-MTU discovery can not work on traffic towards the
2147 clients. This is the case when the intercepting device
2148 does not fully track connections and fails to forward
2149 ICMP must fragment messages to the cache server. If you
2150 have such setup and experience that certain clients
2151 sporadically hang or never complete requests set
2152 disable-pmtu-discovery option to 'transparent'.
2154 name= Specifies a internal name for the port. Defaults to
2155 the port specification (port or addr:port)
2157 tcpkeepalive[=idle,interval,timeout]
2158 Enable TCP keepalive probes of idle connections.
2159 In seconds; idle is the initial time before TCP starts
2160 probing the connection, interval how often to probe, and
2161 timeout the time before giving up.
2163 require-proxy-header
2164 Require PROXY protocol version 1 or 2 connections.
2165 The proxy_protocol_access is required to whitelist
2166 downstream proxies which can be trusted.
2168 If you run Squid on a dual-homed machine with an internal
2169 and an external interface we recommend you to specify the
2170 internal address:port in http_port. This way Squid will only be
2171 visible on the internal address.
2175 # Squid normally listens to port 3128
2176 http_port @DEFAULT_HTTP_PORT@
2181 IFDEF: USE_GNUTLS||USE_OPENSSL
2186 Usage: [ip:]port [mode] cert=certificate.pem [options]
2188 The socket address where Squid will listen for client requests made
2189 over TLS or SSL connections. Commonly referred to as HTTPS.
2191 This is most useful for situations where you are running squid in
2192 accelerator mode and you want to do the TLS work at the accelerator level.
2194 You may specify multiple socket addresses on multiple lines,
2195 each with their own certificate and/or options.
2197 The TLS cert= option is mandatory on HTTPS ports.
2199 See http_port for a list of modes and options.
2207 Enables Native FTP proxy by specifying the socket address where Squid
2208 listens for FTP client requests. See http_port directive for various
2209 ways to specify the listening address and mode.
2211 Usage: ftp_port address [mode] [options]
2213 WARNING: This is a new, experimental, complex feature that has seen
2214 limited production exposure. Some Squid modules (e.g., caching) do not
2215 currently work with native FTP proxying, and many features have not
2216 even been tested for compatibility. Test well before deploying!
2218 Native FTP proxying differs substantially from proxying HTTP requests
2219 with ftp:// URIs because Squid works as an FTP server and receives
2220 actual FTP commands (rather than HTTP requests with FTP URLs).
2222 Native FTP commands accepted at ftp_port are internally converted or
2223 wrapped into HTTP-like messages. The same happens to Native FTP
2224 responses received from FTP origin servers. Those HTTP-like messages
2225 are shoveled through regular access control and adaptation layers
2226 between the FTP client and the FTP origin server. This allows Squid to
2227 examine, adapt, block, and log FTP exchanges. Squid reuses most HTTP
2228 mechanisms when shoveling wrapped FTP messages. For example,
2229 http_access and adaptation_access directives are used.
2233 intercept Same as http_port intercept. The FTP origin address is
2234 determined based on the intended destination of the
2235 intercepted connection.
2237 tproxy Support Linux TPROXY for spoofing outgoing
2238 connections using the client IP address.
2239 NP: disables authentication and maybe IPv6 on the port.
2241 By default (i.e., without an explicit mode option), Squid extracts the
2242 FTP origin address from the login@origin parameter of the FTP USER
2243 command. Many popular FTP clients support such native FTP proxying.
2247 name=token Specifies an internal name for the port. Defaults to
2248 the port address. Usable with myportname ACL.
2251 Enables tracking of FTP directories by injecting extra
2252 PWD commands and adjusting Request-URI (in wrapping
2253 HTTP requests) to reflect the current FTP server
2254 directory. Tracking is disabled by default.
2256 protocol=FTP Protocol to reconstruct accelerated and intercepted
2257 requests with. Defaults to FTP. No other accepted
2258 values have been tested with. An unsupported value
2259 results in a FATAL error. Accepted values are FTP,
2260 HTTP (or HTTP/1.1), and HTTPS (or HTTPS/1.1).
2262 Other http_port modes and options that are not specific to HTTP and
2263 HTTPS may also work.
2266 NAME: tcp_outgoing_tos tcp_outgoing_ds tcp_outgoing_dscp
2269 LOC: Ip::Qos::TheConfig.tosToServer
2271 Allows you to select a TOS/Diffserv value for packets outgoing
2272 on the server side, based on an ACL.
2274 tcp_outgoing_tos ds-field [!]aclname ...
2276 Example where normal_service_net uses the TOS value 0x00
2277 and good_service_net uses 0x20
2279 acl normal_service_net src 10.0.0.0/24
2280 acl good_service_net src 10.0.1.0/24
2281 tcp_outgoing_tos 0x00 normal_service_net
2282 tcp_outgoing_tos 0x20 good_service_net
2284 TOS/DSCP values really only have local significance - so you should
2285 know what you're specifying. For more information, see RFC2474,
2286 RFC2475, and RFC3260.
2288 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
2289 "default" to use whatever default your host has.
2290 Note that only multiples of 4 are usable as the two rightmost bits have
2291 been redefined for use by ECN (RFC 3168 section 23.1).
2292 The squid parser will enforce this by masking away the ECN bits.
2294 Processing proceeds in the order specified, and stops at first fully
2297 Only fast ACLs are supported.
2300 NAME: clientside_tos
2303 LOC: Ip::Qos::TheConfig.tosToClient
2305 Allows you to select a TOS/DSCP value for packets being transmitted
2306 on the client-side, based on an ACL.
2308 clientside_tos ds-field [!]aclname ...
2310 Example where normal_service_net uses the TOS value 0x00
2311 and good_service_net uses 0x20
2313 acl normal_service_net src 10.0.0.0/24
2314 acl good_service_net src 10.0.1.0/24
2315 clientside_tos 0x00 normal_service_net
2316 clientside_tos 0x20 good_service_net
2318 Note: This feature is incompatible with qos_flows. Any TOS values set here
2319 will be overwritten by TOS values in qos_flows.
2321 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
2322 "default" to use whatever default your host has.
2323 Note that only multiples of 4 are usable as the two rightmost bits have
2324 been redefined for use by ECN (RFC 3168 section 23.1).
2325 The squid parser will enforce this by masking away the ECN bits.
2329 NAME: tcp_outgoing_mark
2331 IFDEF: SO_MARK&&USE_LIBCAP
2333 LOC: Ip::Qos::TheConfig.nfmarkToServer
2335 Allows you to apply a Netfilter mark value to outgoing packets
2336 on the server side, based on an ACL.
2338 tcp_outgoing_mark mark-value [!]aclname ...
2340 Example where normal_service_net uses the mark value 0x00
2341 and good_service_net uses 0x20
2343 acl normal_service_net src 10.0.0.0/24
2344 acl good_service_net src 10.0.1.0/24
2345 tcp_outgoing_mark 0x00 normal_service_net
2346 tcp_outgoing_mark 0x20 good_service_net
2348 Only fast ACLs are supported.
2351 NAME: clientside_mark
2353 IFDEF: SO_MARK&&USE_LIBCAP
2355 LOC: Ip::Qos::TheConfig.nfmarkToClient
2357 Allows you to apply a Netfilter mark value to packets being transmitted
2358 on the client-side, based on an ACL.
2360 clientside_mark mark-value [!]aclname ...
2362 Example where normal_service_net uses the mark value 0x00
2363 and good_service_net uses 0x20
2365 acl normal_service_net src 10.0.0.0/24
2366 acl good_service_net src 10.0.1.0/24
2367 clientside_mark 0x00 normal_service_net
2368 clientside_mark 0x20 good_service_net
2370 Note: This feature is incompatible with qos_flows. Any mark values set here
2371 will be overwritten by mark values in qos_flows.
2378 LOC: Ip::Qos::TheConfig
2380 Allows you to select a TOS/DSCP value to mark outgoing
2381 connections to the client, based on where the reply was sourced.
2382 For platforms using netfilter, allows you to set a netfilter mark
2383 value instead of, or in addition to, a TOS value.
2385 By default this functionality is disabled. To enable it with the default
2386 settings simply use "qos_flows mark" or "qos_flows tos". Default
2387 settings will result in the netfilter mark or TOS value being copied
2388 from the upstream connection to the client. Note that it is the connection
2389 CONNMARK value not the packet MARK value that is copied.
2391 It is not currently possible to copy the mark or TOS value from the
2392 client to the upstream connection request.
2394 TOS values really only have local significance - so you should
2395 know what you're specifying. For more information, see RFC2474,
2396 RFC2475, and RFC3260.
2398 The TOS/DSCP byte must be exactly that - a octet value 0 - 255.
2399 Note that only multiples of 4 are usable as the two rightmost bits have
2400 been redefined for use by ECN (RFC 3168 section 23.1).
2401 The squid parser will enforce this by masking away the ECN bits.
2403 Mark values can be any unsigned 32-bit integer value.
2405 This setting is configured by setting the following values:
2407 tos|mark Whether to set TOS or netfilter mark values
2409 local-hit=0xFF Value to mark local cache hits.
2411 sibling-hit=0xFF Value to mark hits from sibling peers.
2413 parent-hit=0xFF Value to mark hits from parent peers.
2415 miss=0xFF[/mask] Value to mark cache misses. Takes precedence
2416 over the preserve-miss feature (see below), unless
2417 mask is specified, in which case only the bits
2418 specified in the mask are written.
2420 The TOS variant of the following features are only possible on Linux
2421 and require your kernel to be patched with the TOS preserving ZPH
2422 patch, available from http://zph.bratcheda.org
2423 No patch is needed to preserve the netfilter mark, which will work
2424 with all variants of netfilter.
2426 disable-preserve-miss
2427 This option disables the preservation of the TOS or netfilter
2428 mark. By default, the existing TOS or netfilter mark value of
2429 the response coming from the remote server will be retained
2430 and masked with miss-mark.
2431 NOTE: in the case of a netfilter mark, the mark must be set on
2432 the connection (using the CONNMARK target) not on the packet
2436 Allows you to mask certain bits in the TOS or mark value
2437 received from the remote server, before copying the value to
2438 the TOS sent towards clients.
2439 Default for tos: 0xFF (TOS from server is not changed).
2440 Default for mark: 0xFFFFFFFF (mark from server is not changed).
2442 All of these features require the --enable-zph-qos compilation flag
2443 (enabled by default). Netfilter marking also requires the
2444 libnetfilter_conntrack libraries (--with-netfilter-conntrack) and
2445 libcap 2.09+ (--with-libcap).
2449 NAME: tcp_outgoing_address
2452 DEFAULT_DOC: Address selection is performed by the operating system.
2453 LOC: Config.accessList.outgoing_address
2455 Allows you to map requests to different outgoing IP addresses
2456 based on the username or source address of the user making
2459 tcp_outgoing_address ipaddr [[!]aclname] ...
2462 Forwarding clients with dedicated IPs for certain subnets.
2464 acl normal_service_net src 10.0.0.0/24
2465 acl good_service_net src 10.0.2.0/24
2467 tcp_outgoing_address 2001:db8::c001 good_service_net
2468 tcp_outgoing_address 10.1.0.2 good_service_net
2470 tcp_outgoing_address 2001:db8::beef normal_service_net
2471 tcp_outgoing_address 10.1.0.1 normal_service_net
2473 tcp_outgoing_address 2001:db8::1
2474 tcp_outgoing_address 10.1.0.3
2476 Processing proceeds in the order specified, and stops at first fully
2479 Squid will add an implicit IP version test to each line.
2480 Requests going to IPv4 websites will use the outgoing 10.1.0.* addresses.
2481 Requests going to IPv6 websites will use the outgoing 2001:db8:* addresses.
2484 NOTE: The use of this directive using client dependent ACLs is
2485 incompatible with the use of server side persistent connections. To
2486 ensure correct results it is best to set server_persistent_connections
2487 to off when using this directive in such configurations.
2489 NOTE: The use of this directive to set a local IP on outgoing TCP links
2490 is incompatible with using TPROXY to set client IP out outbound TCP links.
2491 When needing to contact peers use the no-tproxy cache_peer option and the
2492 client_dst_passthru directive re-enable normal forwarding such as this.
2496 NAME: host_verify_strict
2499 LOC: Config.onoff.hostStrictVerify
2501 Regardless of this option setting, when dealing with intercepted
2502 traffic, Squid always verifies that the destination IP address matches
2503 the Host header domain or IP (called 'authority form URL').
2505 This enforcement is performed to satisfy a MUST-level requirement in
2506 RFC 2616 section 14.23: "The Host field value MUST represent the naming
2507 authority of the origin server or gateway given by the original URL".
2510 Squid always responds with an HTTP 409 (Conflict) error
2511 page and logs a security warning if there is no match.
2513 Squid verifies that the destination IP address matches
2514 the Host header for forward-proxy and reverse-proxy traffic
2515 as well. For those traffic types, Squid also enables the
2516 following checks, comparing the corresponding Host header
2517 and Request-URI components:
2519 * The host names (domain or IP) must be identical,
2520 but valueless or missing Host header disables all checks.
2521 For the two host names to match, both must be either IP
2524 * Port numbers must be identical, but if a port is missing
2525 the scheme-default port is assumed.
2528 When set to OFF (the default):
2529 Squid allows suspicious requests to continue but logs a
2530 security warning and blocks caching of the response.
2532 * Forward-proxy traffic is not checked at all.
2534 * Reverse-proxy traffic is not checked at all.
2536 * Intercepted traffic which passes verification is handled
2537 according to client_dst_passthru.
2539 * Intercepted requests which fail verification are sent
2540 to the client original destination instead of DIRECT.
2541 This overrides 'client_dst_passthru off'.
2543 For now suspicious intercepted CONNECT requests are always
2544 responded to with an HTTP 409 (Conflict) error page.
2549 As described in CVE-2009-0801 when the Host: header alone is used
2550 to determine the destination of a request it becomes trivial for
2551 malicious scripts on remote websites to bypass browser same-origin
2552 security policy and sandboxing protections.
2554 The cause of this is that such applets are allowed to perform their
2555 own HTTP stack, in which case the same-origin policy of the browser
2556 sandbox only verifies that the applet tries to contact the same IP
2557 as from where it was loaded at the IP level. The Host: header may
2558 be different from the connected IP and approved origin.
2562 NAME: client_dst_passthru
2565 LOC: Config.onoff.client_dst_passthru
2567 With NAT or TPROXY intercepted traffic Squid may pass the request
2568 directly to the original client destination IP or seek a faster
2569 source using the HTTP Host header.
2571 Using Host to locate alternative servers can provide faster
2572 connectivity with a range of failure recovery options.
2573 But can also lead to connectivity trouble when the client and
2574 server are attempting stateful interactions unaware of the proxy.
2576 This option (on by default) prevents alternative DNS entries being
2577 located to send intercepted traffic DIRECT to an origin server.
2578 The clients original destination IP and port will be used instead.
2580 Regardless of this option setting, when dealing with intercepted
2581 traffic Squid will verify the Host: header and any traffic which
2582 fails Host verification will be treated as if this option were ON.
2584 see host_verify_strict for details on the verification process.
2589 -----------------------------------------------------------------------------
2592 NAME: tls_outgoing_options
2593 IFDEF: USE_GNUTLS||USE_OPENSSL
2594 TYPE: securePeerOptions
2595 DEFAULT: min-version=1.0
2596 LOC: Security::ProxyOutgoingConfig
2598 disable Do not support https:// URLs.
2600 cert=/path/to/client/certificate
2601 A client TLS certificate to use when connecting.
2603 key=/path/to/client/private_key
2604 The private TLS key corresponding to the cert= above.
2605 If key= is not specified cert= is assumed to reference
2606 a PEM file containing both the certificate and the key.
2608 cipher=... The list of valid TLS ciphers to use.
2611 The minimum TLS protocol version to permit.
2612 To control SSLv3 use the options= parameter.
2613 Supported Values: 1.0 (default), 1.1, 1.2
2615 options=... Specify various TLS/SSL implementation options:
2617 NO_SSLv3 Disallow the use of SSLv3
2619 NO_TLSv1 Disallow the use of TLSv1.0
2621 NO_TLSv1_1 Disallow the use of TLSv1.1
2623 NO_TLSv1_2 Disallow the use of TLSv1.2
2626 Always create a new key when using
2627 temporary/ephemeral DH key exchanges
2630 Disable use of RFC5077 session tickets.
2631 Some servers may have problems
2632 understanding the TLS extension due
2633 to ambiguous specification in RFC4507.
2635 ALL Enable various bug workarounds
2636 suggested as "harmless" by OpenSSL
2637 Be warned that this reduces SSL/TLS
2638 strength to some attacks.
2640 See the OpenSSL SSL_CTX_set_options documentation for a
2643 cafile= PEM file containing CA certificates to use when verifying
2644 the peer certificate. May be repeated to load multiple files.
2646 capath= A directory containing additional CA certificates to
2647 use when verifying the peer certificate.
2648 Requires OpenSSL or LibreSSL.
2650 crlfile=... A certificate revocation list file to use when
2651 verifying the peer certificate.
2653 flags=... Specify various flags modifying the TLS implementation:
2656 Accept certificates even if they fail to
2659 Don't verify the peer certificate
2660 matches the server name
2663 Whether to use the system Trusted CAs. Default is ON.
2665 domain= The peer name as advertised in its certificate.
2666 Used for verifying the correctness of the received peer
2667 certificate. If not specified the peer hostname will be
2673 -----------------------------------------------------------------------------
2676 NAME: ssl_unclean_shutdown
2680 LOC: Config.SSL.unclean_shutdown
2682 Some browsers (especially MSIE) bugs out on SSL shutdown
2689 LOC: Config.SSL.ssl_engine
2692 The OpenSSL engine to use. You will need to set this if you
2693 would like to use hardware SSL acceleration for example.
2696 NAME: sslproxy_session_ttl
2699 LOC: Config.SSL.session_ttl
2702 Sets the timeout value for SSL sessions
2705 NAME: sslproxy_session_cache_size
2708 LOC: Config.SSL.sessionCacheSize
2711 Sets the cache size to use for ssl session
2714 NAME: sslproxy_foreign_intermediate_certs
2717 LOC: Config.ssl_client.foreignIntermediateCertsPath
2720 Many origin servers fail to send their full server certificate
2721 chain for verification, assuming the client already has or can
2722 easily locate any missing intermediate certificates.
2724 Squid uses the certificates from the specified file to fill in
2725 these missing chains when trying to validate origin server
2728 The file is expected to contain zero or more PEM-encoded
2729 intermediate certificates. These certificates are not treated
2730 as trusted root certificates, and any self-signed certificate in
2731 this file will be ignored.
2734 NAME: sslproxy_cert_sign_hash
2737 LOC: Config.SSL.certSignHash
2740 Sets the hashing algorithm to use when signing generated certificates.
2741 Valid algorithm names depend on the OpenSSL library used. The following
2742 names are usually available: sha1, sha256, sha512, and md5. Please see
2743 your OpenSSL library manual for the available hashes. By default, Squids
2744 that support this option use sha256 hashes.
2746 Squid does not forcefully purge cached certificates that were generated
2747 with an algorithm other than the currently configured one. They remain
2748 in the cache, subject to the regular cache eviction policy, and become
2749 useful if the algorithm changes again.
2754 TYPE: sslproxy_ssl_bump
2755 LOC: Config.accessList.ssl_bump
2756 DEFAULT_DOC: Become a TCP tunnel without decrypting proxied traffic.
2759 This option is consulted when a CONNECT request is received on
2760 an http_port (or a new connection is intercepted at an
2761 https_port), provided that port was configured with an ssl-bump
2762 flag. The subsequent data on the connection is either treated as
2763 HTTPS and decrypted OR tunneled at TCP level without decryption,
2764 depending on the first matching bumping "action".
2766 ssl_bump <action> [!]acl ...
2768 The following bumping actions are currently supported:
2771 Become a TCP tunnel without decrypting proxied traffic.
2772 This is the default action.
2775 Establish a secure connection with the server and, using a
2776 mimicked server certificate, with the client.
2779 Receive client (step SslBump1) or server (step SslBump2)
2780 certificate while preserving the possibility of splicing the
2781 connection. Peeking at the server certificate (during step 2)
2782 usually precludes bumping of the connection at step 3.
2785 Receive client (step SslBump1) or server (step SslBump2)
2786 certificate while preserving the possibility of bumping the
2787 connection. Staring at the server certificate (during step 2)
2788 usually precludes splicing of the connection at step 3.
2791 Close client and server connections.
2793 Backward compatibility actions available at step SslBump1:
2796 Bump the connection. Establish a secure connection with the
2797 client first, then connect to the server. This old mode does
2798 not allow Squid to mimic server SSL certificate and does not
2799 work with intercepted SSL connections.
2802 Bump the connection. Establish a secure connection with the
2803 server first, then establish a secure connection with the
2804 client, using a mimicked server certificate. Works with both
2805 CONNECT requests and intercepted SSL connections, but does
2806 not allow to make decisions based on SSL handshake info.
2809 Decide whether to bump or splice the connection based on
2810 client-to-squid and server-to-squid SSL hello messages.
2814 Same as the "splice" action.
2816 All ssl_bump rules are evaluated at each of the supported bumping
2817 steps. Rules with actions that are impossible at the current step are
2818 ignored. The first matching ssl_bump action wins and is applied at the
2819 end of the current step. If no rules match, the splice action is used.
2820 See the at_step ACL for a list of the supported SslBump steps.
2822 This clause supports both fast and slow acl types.
2823 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2825 See also: http_port ssl-bump, https_port ssl-bump, and acl at_step.
2828 # Example: Bump all TLS connections except those originating from
2829 # localhost or those going to example.com.
2831 acl broken_sites ssl::server_name .example.com
2832 ssl_bump splice localhost
2833 ssl_bump splice broken_sites
2837 NAME: sslproxy_cert_error
2840 DEFAULT_DOC: Server certificate errors terminate the transaction.
2841 LOC: Config.ssl_client.cert_error
2844 Use this ACL to bypass server certificate validation errors.
2846 For example, the following lines will bypass all validation errors
2847 when talking to servers for example.com. All other
2848 validation errors will result in ERR_SECURE_CONNECT_FAIL error.
2850 acl BrokenButTrustedServers dstdomain example.com
2851 sslproxy_cert_error allow BrokenButTrustedServers
2852 sslproxy_cert_error deny all
2854 This clause only supports fast acl types.
2855 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2856 Using slow acl types may result in server crashes
2858 Without this option, all server certificate validation errors
2859 terminate the transaction to protect Squid and the client.
2861 SQUID_X509_V_ERR_INFINITE_VALIDATION error cannot be bypassed
2862 but should not happen unless your OpenSSL library is buggy.
2865 Bypassing validation errors is dangerous because an
2866 error usually implies that the server cannot be trusted
2867 and the connection may be insecure.
2869 See also: sslproxy_flags and DONT_VERIFY_PEER.
2872 NAME: sslproxy_cert_sign
2875 POSTSCRIPTUM: signUntrusted ssl::certUntrusted
2876 POSTSCRIPTUM: signSelf ssl::certSelfSigned
2877 POSTSCRIPTUM: signTrusted all
2878 TYPE: sslproxy_cert_sign
2879 LOC: Config.ssl_client.cert_sign
2882 sslproxy_cert_sign <signing algorithm> acl ...
2884 The following certificate signing algorithms are supported:
2887 Sign using the configured CA certificate which is usually
2888 placed in and trusted by end-user browsers. This is the
2889 default for trusted origin server certificates.
2892 Sign to guarantee an X509_V_ERR_CERT_UNTRUSTED browser error.
2893 This is the default for untrusted origin server certificates
2894 that are not self-signed (see ssl::certUntrusted).
2897 Sign using a self-signed certificate with the right CN to
2898 generate a X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT error in the
2899 browser. This is the default for self-signed origin server
2900 certificates (see ssl::certSelfSigned).
2902 This clause only supports fast acl types.
2904 When sslproxy_cert_sign acl(s) match, Squid uses the corresponding
2905 signing algorithm to generate the certificate and ignores all
2906 subsequent sslproxy_cert_sign options (the first match wins). If no
2907 acl(s) match, the default signing algorithm is determined by errors
2908 detected when obtaining and validating the origin server certificate.
2910 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2911 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2912 CONNECT request that carries a domain name. In all other cases (CONNECT
2913 to an IP address or an intercepted SSL connection), Squid cannot detect
2914 the domain mismatch at certificate generation time when
2915 bump-server-first is used.
2918 NAME: sslproxy_cert_adapt
2921 TYPE: sslproxy_cert_adapt
2922 LOC: Config.ssl_client.cert_adapt
2925 sslproxy_cert_adapt <adaptation algorithm> acl ...
2927 The following certificate adaptation algorithms are supported:
2930 Sets the "Not After" property to the "Not After" property of
2931 the CA certificate used to sign generated certificates.
2934 Sets the "Not Before" property to the "Not Before" property of
2935 the CA certificate used to sign generated certificates.
2937 setCommonName or setCommonName{CN}
2938 Sets Subject.CN property to the host name specified as a
2939 CN parameter or, if no explicit CN parameter was specified,
2940 extracted from the CONNECT request. It is a misconfiguration
2941 to use setCommonName without an explicit parameter for
2942 intercepted or tproxied SSL connections.
2944 This clause only supports fast acl types.
2946 Squid first groups sslproxy_cert_adapt options by adaptation algorithm.
2947 Within a group, when sslproxy_cert_adapt acl(s) match, Squid uses the
2948 corresponding adaptation algorithm to generate the certificate and
2949 ignores all subsequent sslproxy_cert_adapt options in that algorithm's
2950 group (i.e., the first match wins within each algorithm group). If no
2951 acl(s) match, the default mimicking action takes place.
2953 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2954 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2955 CONNECT request that carries a domain name. In all other cases (CONNECT
2956 to an IP address or an intercepted SSL connection), Squid cannot detect
2957 the domain mismatch at certificate generation time when
2958 bump-server-first is used.
2961 NAME: sslpassword_program
2964 LOC: Config.Program.ssl_password
2967 Specify a program used for entering SSL key passphrases
2968 when using encrypted SSL certificate keys. If not specified
2969 keys must either be unencrypted, or Squid started with the -N
2970 option to allow it to query interactively for the passphrase.
2972 The key file name is given as argument to the program allowing
2973 selection of the right password if you have multiple encrypted
2978 OPTIONS RELATING TO EXTERNAL SSL_CRTD
2979 -----------------------------------------------------------------------------
2982 NAME: sslcrtd_program
2985 DEFAULT: @DEFAULT_SSL_CRTD@ -s @DEFAULT_SSL_DB_DIR@ -M 4MB
2986 LOC: Ssl::TheConfig.ssl_crtd
2988 Specify the location and options of the executable for certificate
2990 @DEFAULT_SSL_CRTD@ program requires -s and -M parameters
2991 For more information use:
2992 @DEFAULT_SSL_CRTD@ -h
2995 NAME: sslcrtd_children
2996 TYPE: HelperChildConfig
2998 DEFAULT: 32 startup=5 idle=1
2999 LOC: Ssl::TheConfig.ssl_crtdChildren
3001 The maximum number of processes spawn to service ssl server.
3002 The maximum this may be safely set to is 32.
3004 The startup= and idle= options allow some measure of skew in your
3009 Sets the minimum number of processes to spawn when Squid
3010 starts or reconfigures. When set to zero the first request will
3011 cause spawning of the first child process to handle it.
3013 Starting too few children temporary slows Squid under load while it
3014 tries to spawn enough additional processes to cope with traffic.
3018 Sets a minimum of how many processes Squid is to try and keep available
3019 at all times. When traffic begins to rise above what the existing
3020 processes can handle this many more will be spawned up to the maximum
3021 configured. A minimum setting of 1 is required.
3025 Sets the maximum number of queued requests.
3026 If the queued requests exceed queue size for more than 3 minutes
3027 squid aborts its operation.
3028 The default value is set to 2*numberofchildren.
3030 You must have at least one ssl_crtd process.
3033 NAME: sslcrtvalidator_program
3037 LOC: Ssl::TheConfig.ssl_crt_validator
3039 Specify the location and options of the executable for ssl_crt_validator
3042 Usage: sslcrtvalidator_program [ttl=n] [cache=n] path ...
3045 ttl=n TTL in seconds for cached results. The default is 60 secs
3046 cache=n limit the result cache size. The default value is 2048
3049 NAME: sslcrtvalidator_children
3050 TYPE: HelperChildConfig
3052 DEFAULT: 32 startup=5 idle=1 concurrency=1
3053 LOC: Ssl::TheConfig.ssl_crt_validator_Children
3055 The maximum number of processes spawn to service SSL server.
3056 The maximum this may be safely set to is 32.
3058 The startup= and idle= options allow some measure of skew in your
3063 Sets the minimum number of processes to spawn when Squid
3064 starts or reconfigures. When set to zero the first request will
3065 cause spawning of the first child process to handle it.
3067 Starting too few children temporary slows Squid under load while it
3068 tries to spawn enough additional processes to cope with traffic.
3072 Sets a minimum of how many processes Squid is to try and keep available
3073 at all times. When traffic begins to rise above what the existing
3074 processes can handle this many more will be spawned up to the maximum
3075 configured. A minimum setting of 1 is required.
3079 The number of requests each certificate validator helper can handle in
3080 parallel. A value of 0 indicates the certficate validator does not
3081 support concurrency. Defaults to 1.
3083 When this directive is set to a value >= 1 then the protocol
3084 used to communicate with the helper is modified to include
3085 a request ID in front of the request/response. The request
3086 ID from the request must be echoed back with the response
3091 Sets the maximum number of queued requests.
3092 If the queued requests exceed queue size for more than 3 minutes
3093 squid aborts its operation.
3094 The default value is set to 2*numberofchildren.
3096 You must have at least one ssl_crt_validator process.
3100 OPTIONS WHICH AFFECT THE NEIGHBOR SELECTION ALGORITHM
3101 -----------------------------------------------------------------------------
3109 To specify other caches in a hierarchy, use the format:
3111 cache_peer hostname type http-port icp-port [options]
3116 # hostname type port port options
3117 # -------------------- -------- ----- ----- -----------
3118 cache_peer parent.foo.net parent 3128 3130 default
3119 cache_peer sib1.foo.net sibling 3128 3130 proxy-only
3120 cache_peer sib2.foo.net sibling 3128 3130 proxy-only
3121 cache_peer example.com parent 80 0 default
3122 cache_peer cdn.example.com sibling 3128 0
3124 type: either 'parent', 'sibling', or 'multicast'.
3126 proxy-port: The port number where the peer accept HTTP requests.
3127 For other Squid proxies this is usually 3128
3128 For web servers this is usually 80
3130 icp-port: Used for querying neighbor caches about objects.
3131 Set to 0 if the peer does not support ICP or HTCP.
3132 See ICP and HTCP options below for additional details.
3135 ==== ICP OPTIONS ====
3137 You MUST also set icp_port and icp_access explicitly when using these options.
3138 The defaults will prevent peer traffic using ICP.
3141 no-query Disable ICP queries to this neighbor.
3144 Indicates the named peer is a member of a multicast group.
3145 ICP queries will not be sent directly to the peer, but ICP
3146 replies will be accepted from it.
3148 closest-only Indicates that, for ICP_OP_MISS replies, we'll only forward
3149 CLOSEST_PARENT_MISSes and never FIRST_PARENT_MISSes.
3152 To only send ICP queries to this neighbor infrequently.
3153 This is used to keep the neighbor round trip time updated
3154 and is usually used in conjunction with weighted-round-robin.
3157 ==== HTCP OPTIONS ====
3159 You MUST also set htcp_port and htcp_access explicitly when using these options.
3160 The defaults will prevent peer traffic using HTCP.
3163 htcp Send HTCP, instead of ICP, queries to the neighbor.
3164 You probably also want to set the "icp-port" to 4827
3165 instead of 3130. This directive accepts a comma separated
3166 list of options described below.
3168 htcp=oldsquid Send HTCP to old Squid versions (2.5 or earlier).
3170 htcp=no-clr Send HTCP to the neighbor but without
3171 sending any CLR requests. This cannot be used with
3174 htcp=only-clr Send HTCP to the neighbor but ONLY CLR requests.
3175 This cannot be used with no-clr.
3178 Send HTCP to the neighbor including CLRs but only when
3179 they do not result from PURGE requests.
3182 Forward any HTCP CLR requests this proxy receives to the peer.
3185 ==== PEER SELECTION METHODS ====
3187 The default peer selection method is ICP, with the first responding peer
3188 being used as source. These options can be used for better load balancing.
3191 default This is a parent cache which can be used as a "last-resort"
3192 if a peer cannot be located by any of the peer-selection methods.
3193 If specified more than once, only the first is used.
3195 round-robin Load-Balance parents which should be used in a round-robin
3196 fashion in the absence of any ICP queries.
3197 weight=N can be used to add bias.
3199 weighted-round-robin
3200 Load-Balance parents which should be used in a round-robin
3201 fashion with the frequency of each parent being based on the
3202 round trip time. Closer parents are used more often.
3203 Usually used for background-ping parents.
3204 weight=N can be used to add bias.
3206 carp Load-Balance parents which should be used as a CARP array.
3207 The requests will be distributed among the parents based on the
3208 CARP load balancing hash function based on their weight.
3210 userhash Load-balance parents based on the client proxy_auth or ident username.
3212 sourcehash Load-balance parents based on the client source IP.
3215 To be used only for cache peers of type "multicast".
3216 ALL members of this multicast group have "sibling"
3217 relationship with it, not "parent". This is to a multicast
3218 group when the requested object would be fetched only from
3219 a "parent" cache, anyway. It's useful, e.g., when
3220 configuring a pool of redundant Squid proxies, being
3221 members of the same multicast group.
3224 ==== PEER SELECTION OPTIONS ====
3226 weight=N use to affect the selection of a peer during any weighted
3227 peer-selection mechanisms.
3228 The weight must be an integer; default is 1,
3229 larger weights are favored more.
3230 This option does not affect parent selection if a peering
3231 protocol is not in use.
3233 basetime=N Specify a base amount to be subtracted from round trip
3235 It is subtracted before division by weight in calculating
3236 which parent to fectch from. If the rtt is less than the
3237 base time the rtt is set to a minimal value.
3239 ttl=N Specify a TTL to use when sending multicast ICP queries
3241 Only useful when sending to a multicast group.
3242 Because we don't accept ICP replies from random
3243 hosts, you must configure other group members as
3244 peers with the 'multicast-responder' option.
3246 no-delay To prevent access to this neighbor from influencing the
3249 digest-url=URL Tell Squid to fetch the cache digest (if digests are
3250 enabled) for this host from the specified URL rather
3251 than the Squid default location.
3254 ==== CARP OPTIONS ====
3256 carp-key=key-specification
3257 use a different key than the full URL to hash against the peer.
3258 the key-specification is a comma-separated list of the keywords
3259 scheme, host, port, path, params
3260 Order is not important.
3262 ==== ACCELERATOR / REVERSE-PROXY OPTIONS ====
3264 originserver Causes this parent to be contacted as an origin server.
3265 Meant to be used in accelerator setups when the peer
3269 Set the Host header of requests forwarded to this peer.
3270 Useful in accelerator setups where the server (peer)
3271 expects a certain domain name but clients may request
3272 others. ie example.com or www.example.com
3274 no-digest Disable request of cache digests.
3277 Disables requesting ICMP RTT database (NetDB).
3280 ==== AUTHENTICATION OPTIONS ====
3283 If this is a personal/workgroup proxy and your parent
3284 requires proxy authentication.
3286 Note: The string can include URL escapes (i.e. %20 for
3287 spaces). This also means % must be written as %%.
3290 Send login details received from client to this peer.
3291 Both Proxy- and WWW-Authorization headers are passed
3292 without alteration to the peer.
3293 Authentication is not required by Squid for this to work.
3295 Note: This will pass any form of authentication but
3296 only Basic auth will work through a proxy unless the
3297 connection-auth options are also used.
3299 login=PASS Send login details received from client to this peer.
3300 Authentication is not required by this option.
3302 If there are no client-provided authentication headers
3303 to pass on, but username and password are available
3304 from an external ACL user= and password= result tags
3305 they may be sent instead.
3307 Note: To combine this with proxy_auth both proxies must
3308 share the same user database as HTTP only allows for
3309 a single login (one for proxy, one for origin server).
3310 Also be warned this will expose your users proxy
3311 password to the peer. USE WITH CAUTION
3314 Send the username to the upstream cache, but with a
3315 fixed password. This is meant to be used when the peer
3316 is in another administrative domain, but it is still
3317 needed to identify each user.
3318 The star can optionally be followed by some extra
3319 information which is added to the username. This can
3320 be used to identify this proxy to the peer, similar to
3321 the login=username:password option above.
3324 If this is a personal/workgroup proxy and your parent
3325 requires a secure proxy authentication.
3326 The first principal from the default keytab or defined by
3327 the environment variable KRB5_KTNAME will be used.
3329 WARNING: The connection may transmit requests from multiple
3330 clients. Negotiate often assumes end-to-end authentication
3331 and a single-client. Which is not strictly true here.
3333 login=NEGOTIATE:principal_name
3334 If this is a personal/workgroup proxy and your parent
3335 requires a secure proxy authentication.
3336 The principal principal_name from the default keytab or
3337 defined by the environment variable KRB5_KTNAME will be
3340 WARNING: The connection may transmit requests from multiple
3341 clients. Negotiate often assumes end-to-end authentication
3342 and a single-client. Which is not strictly true here.
3344 connection-auth=on|off
3345 Tell Squid that this peer does or not support Microsoft
3346 connection oriented authentication, and any such
3347 challenges received from there should be ignored.
3348 Default is auto to automatically determine the status
3352 Do not use a keytab to authenticate to a peer when
3353 login=NEGOTIATE is specified. Let the GSSAPI
3354 implementation determine which already existing
3355 credentials cache to use instead.
3358 ==== SSL / HTTPS / TLS OPTIONS ====
3360 tls Encrypt connections to this peer with TLS.
3362 sslcert=/path/to/ssl/certificate
3363 A client SSL certificate to use when connecting to
3366 sslkey=/path/to/ssl/key
3367 The private SSL key corresponding to sslcert above.
3368 If 'sslkey' is not specified 'sslcert' is assumed to
3369 reference a combined file containing both the
3370 certificate and the key.
3372 sslcipher=... The list of valid SSL ciphers to use when connecting
3376 The minimum TLS protocol version to permit. To control
3377 SSLv3 use the ssloptions= parameter.
3378 Supported Values: 1.0 (default), 1.1, 1.2
3380 ssloptions=... Specify various SSL implementation options:
3382 NO_SSLv3 Disallow the use of SSLv3
3384 NO_TLSv1 Disallow the use of TLSv1.0
3386 NO_TLSv1_1 Disallow the use of TLSv1.1
3388 NO_TLSv1_2 Disallow the use of TLSv1.2
3391 Always create a new key when using
3392 temporary/ephemeral DH key exchanges
3395 Disable use of RFC5077 session tickets.
3396 Some servers may have problems
3397 understanding the TLS extension due
3398 to ambiguous specification in RFC4507.
3400 ALL Enable various bug workarounds
3401 suggested as "harmless" by OpenSSL
3402 Be warned that this reduces SSL/TLS
3403 strength to some attacks.
3405 See the OpenSSL SSL_CTX_set_options documentation for a
3408 tls-cafile= PEM file containing CA certificates to use when verifying
3409 the peer certificate. May be repeated to load multiple files.
3411 sslcapath=... A directory containing additional CA certificates to
3412 use when verifying the peer certificate.
3413 Requires OpenSSL or LibreSSL.
3415 sslcrlfile=... A certificate revocation list file to use when
3416 verifying the peer certificate.
3418 sslflags=... Specify various flags modifying the SSL implementation:
3421 Accept certificates even if they fail to
3425 Don't verify the peer certificate
3426 matches the server name
3428 ssldomain= The peer name as advertised in it's certificate.
3429 Used for verifying the correctness of the received peer
3430 certificate. If not specified the peer hostname will be
3433 front-end-https[=off|on|auto]
3434 Enable the "Front-End-Https: On" header needed when
3435 using Squid as a SSL frontend in front of Microsoft OWA.
3436 See MS KB document Q307347 for details on this header.
3437 If set to auto the header will only be added if the
3438 request is forwarded as a https:// URL.
3440 tls-default-ca[=off]
3441 Whether to use the system Trusted CAs. Default is ON.
3443 tls-no-npn Do not use the TLS NPN extension to advertise HTTP/1.1.
3445 ==== GENERAL OPTIONS ====
3448 A peer-specific connect timeout.
3449 Also see the peer_connect_timeout directive.
3451 connect-fail-limit=N
3452 How many times connecting to a peer must fail before
3453 it is marked as down. Standby connection failures
3454 count towards this limit. Default is 10.
3456 allow-miss Disable Squid's use of only-if-cached when forwarding
3457 requests to siblings. This is primarily useful when
3458 icp_hit_stale is used by the sibling. Excessive use
3459 of this option may result in forwarding loops. One way
3460 to prevent peering loops when using this option, is to
3461 deny cache peer usage on requests from a peer:
3463 cache_peer_access peerName deny fromPeer
3465 max-conn=N Limit the number of concurrent connections the Squid
3466 may open to this peer, including already opened idle
3467 and standby connections. There is no peer-specific
3468 connection limit by default.
3470 A peer exceeding the limit is not used for new
3471 requests unless a standby connection is available.
3473 max-conn currently works poorly with idle persistent
3474 connections: When a peer reaches its max-conn limit,
3475 and there are idle persistent connections to the peer,
3476 the peer may not be selected because the limiting code
3477 does not know whether Squid can reuse those idle
3480 standby=N Maintain a pool of N "hot standby" connections to an
3481 UP peer, available for requests when no idle
3482 persistent connection is available (or safe) to use.
3483 By default and with zero N, no such pool is maintained.
3484 N must not exceed the max-conn limit (if any).
3486 At start or after reconfiguration, Squid opens new TCP
3487 standby connections until there are N connections
3488 available and then replenishes the standby pool as
3489 opened connections are used up for requests. A used
3490 connection never goes back to the standby pool, but
3491 may go to the regular idle persistent connection pool
3492 shared by all peers and origin servers.
3494 Squid never opens multiple new standby connections
3495 concurrently. This one-at-a-time approach minimizes
3496 flooding-like effect on peers. Furthermore, just a few
3497 standby connections should be sufficient in most cases
3498 to supply most new requests with a ready-to-use
3501 Standby connections obey server_idle_pconn_timeout.
3502 For the feature to work as intended, the peer must be
3503 configured to accept and keep them open longer than
3504 the idle timeout at the connecting Squid, to minimize
3505 race conditions typical to idle used persistent
3506 connections. Default request_timeout and
3507 server_idle_pconn_timeout values ensure such a
3510 name=xxx Unique name for the peer.
3511 Required if you have multiple peers on the same host
3512 but different ports.
3513 This name can be used in cache_peer_access and similar
3514 directives to identify the peer.
3515 Can be used by outgoing access controls through the
3518 no-tproxy Do not use the client-spoof TPROXY support when forwarding
3519 requests to this peer. Use normal address selection instead.
3520 This overrides the spoof_client_ip ACL.
3522 proxy-only objects fetched from the peer will not be stored locally.
3526 NAME: cache_peer_access
3529 DEFAULT_DOC: No peer usage restrictions.
3532 Restricts usage of cache_peer proxies.
3535 cache_peer_access peer-name allow|deny [!]aclname ...
3537 For the required peer-name parameter, use either the value of the
3538 cache_peer name=value parameter or, if name=value is missing, the
3539 cache_peer hostname parameter.
3541 This directive narrows down the selection of peering candidates, but
3542 does not determine the order in which the selected candidates are
3543 contacted. That order is determined by the peer selection algorithms
3544 (see PEER SELECTION sections in the cache_peer documentation).
3546 If a deny rule matches, the corresponding peer will not be contacted
3547 for the current transaction -- Squid will not send ICP queries and
3548 will not forward HTTP requests to that peer. An allow match leaves
3549 the corresponding peer in the selection. The first match for a given
3550 peer wins for that peer.
3552 The relative order of cache_peer_access directives for the same peer
3553 matters. The relative order of any two cache_peer_access directives
3554 for different peers does not matter. To ease interpretation, it is a
3555 good idea to group cache_peer_access directives for the same peer
3558 A single cache_peer_access directive may be evaluated multiple times
3559 for a given transaction because individual peer selection algorithms
3560 may check it independently from each other. These redundant checks
3561 may be optimized away in future Squid versions.
3563 This clause only supports fast acl types.
3564 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
3568 NAME: neighbor_type_domain
3569 TYPE: hostdomaintype
3571 DEFAULT_DOC: The peer type from cache_peer directive is used for all requests to that peer.
3574 Modify the cache_peer neighbor type when passing requests
3575 about specific domains to the peer.
3578 neighbor_type_domain neighbor parent|sibling domain domain ...
3581 cache_peer foo.example.com parent 3128 3130
3582 neighbor_type_domain foo.example.com sibling .au .de
3584 The above configuration treats all requests to foo.example.com as a
3585 parent proxy unless the request is for a .au or .de ccTLD domain name.
3588 NAME: dead_peer_timeout
3592 LOC: Config.Timeout.deadPeer
3594 This controls how long Squid waits to declare a peer cache
3595 as "dead." If there are no ICP replies received in this
3596 amount of time, Squid will declare the peer dead and not
3597 expect to receive any further ICP replies. However, it
3598 continues to send ICP queries, and will mark the peer as
3599 alive upon receipt of the first subsequent ICP reply.
3601 This timeout also affects when Squid expects to receive ICP
3602 replies from peers. If more than 'dead_peer' seconds have
3603 passed since the last ICP reply was received, Squid will not
3604 expect to receive an ICP reply on the next query. Thus, if
3605 your time between requests is greater than this timeout, you
3606 will see a lot of requests sent DIRECT to origin servers
3607 instead of to your parents.
3610 NAME: forward_max_tries
3613 LOC: Config.forward_max_tries
3615 Controls how many different forward paths Squid will try
3616 before giving up. See also forward_timeout.
3618 NOTE: connect_retries (default: none) can make each of these
3619 possible forwarding paths be tried multiple times.
3623 MEMORY CACHE OPTIONS
3624 -----------------------------------------------------------------------------
3631 LOC: Config.memMaxSize
3633 NOTE: THIS PARAMETER DOES NOT SPECIFY THE MAXIMUM PROCESS SIZE.
3634 IT ONLY PLACES A LIMIT ON HOW MUCH ADDITIONAL MEMORY SQUID WILL
3635 USE AS A MEMORY CACHE OF OBJECTS. SQUID USES MEMORY FOR OTHER
3636 THINGS AS WELL. SEE THE SQUID FAQ SECTION 8 FOR DETAILS.
3638 'cache_mem' specifies the ideal amount of memory to be used
3640 * In-Transit objects
3642 * Negative-Cached objects
3644 Data for these objects are stored in 4 KB blocks. This
3645 parameter specifies the ideal upper limit on the total size of
3646 4 KB blocks allocated. In-Transit objects take the highest
3649 In-transit objects have priority over the others. When
3650 additional space is needed for incoming data, negative-cached
3651 and hot objects will be released. In other words, the
3652 negative-cached and hot objects will fill up any unused space
3653 not needed for in-transit objects.
3655 If circumstances require, this limit will be exceeded.
3656 Specifically, if your incoming request rate requires more than
3657 'cache_mem' of memory to hold in-transit objects, Squid will
3658 exceed this limit to satisfy the new requests. When the load
3659 decreases, blocks will be freed until the high-water mark is
3660 reached. Thereafter, blocks will be used to store hot
3663 If shared memory caching is enabled, Squid does not use the shared
3664 cache space for in-transit objects, but they still consume as much
3665 local memory as they need. For more details about the shared memory
3666 cache, see memory_cache_shared.
3669 NAME: maximum_object_size_in_memory
3673 LOC: Config.Store.maxInMemObjSize
3675 Objects greater than this size will not be attempted to kept in
3676 the memory cache. This should be set high enough to keep objects
3677 accessed frequently in memory to improve performance whilst low
3678 enough to keep larger objects from hoarding cache_mem.
3681 NAME: memory_cache_shared
3684 LOC: Config.memShared
3686 DEFAULT_DOC: "on" where supported if doing memory caching with multiple SMP workers.
3688 Controls whether the memory cache is shared among SMP workers.
3690 The shared memory cache is meant to occupy cache_mem bytes and replace
3691 the non-shared memory cache, although some entities may still be
3692 cached locally by workers for now (e.g., internal and in-transit
3693 objects may be served from a local memory cache even if shared memory
3694 caching is enabled).
3696 By default, the memory cache is shared if and only if all of the
3697 following conditions are satisfied: Squid runs in SMP mode with
3698 multiple workers, cache_mem is positive, and Squid environment
3699 supports required IPC primitives (e.g., POSIX shared memory segments
3700 and GCC-style atomic operations).
3702 To avoid blocking locks, shared memory uses opportunistic algorithms
3703 that do not guarantee that every cachable entity that could have been
3704 shared among SMP workers will actually be shared.
3707 NAME: memory_cache_mode
3711 DEFAULT_DOC: Keep the most recently fetched objects in memory
3713 Controls which objects to keep in the memory cache (cache_mem)
3715 always Keep most recently fetched objects in memory (default)
3717 disk Only disk cache hits are kept in memory, which means
3718 an object must first be cached on disk and then hit
3719 a second time before cached in memory.
3721 network Only objects fetched from network is kept in memory
3724 NAME: memory_replacement_policy
3726 LOC: Config.memPolicy
3729 The memory replacement policy parameter determines which
3730 objects are purged from memory when memory space is needed.
3732 See cache_replacement_policy for details on algorithms.
3737 -----------------------------------------------------------------------------
3740 NAME: cache_replacement_policy
3742 LOC: Config.replPolicy
3745 The cache replacement policy parameter determines which
3746 objects are evicted (replaced) when disk space is needed.
3748 lru : Squid's original list based LRU policy
3749 heap GDSF : Greedy-Dual Size Frequency
3750 heap LFUDA: Least Frequently Used with Dynamic Aging
3751 heap LRU : LRU policy implemented using a heap
3753 Applies to any cache_dir lines listed below this directive.
3755 The LRU policies keeps recently referenced objects.
3757 The heap GDSF policy optimizes object hit rate by keeping smaller
3758 popular objects in cache so it has a better chance of getting a
3759 hit. It achieves a lower byte hit rate than LFUDA though since
3760 it evicts larger (possibly popular) objects.
3762 The heap LFUDA policy keeps popular objects in cache regardless of
3763 their size and thus optimizes byte hit rate at the expense of
3764 hit rate since one large, popular object will prevent many
3765 smaller, slightly less popular objects from being cached.
3767 Both policies utilize a dynamic aging mechanism that prevents
3768 cache pollution that can otherwise occur with frequency-based
3769 replacement policies.
3771 NOTE: if using the LFUDA replacement policy you should increase
3772 the value of maximum_object_size above its default of 4 MB to
3773 to maximize the potential byte hit rate improvement of LFUDA.
3775 For more information about the GDSF and LFUDA cache replacement
3776 policies see http://www.hpl.hp.com/techreports/1999/HPL-1999-69.html
3777 and http://fog.hpl.external.hp.com/techreports/98/HPL-98-173.html.
3780 NAME: minimum_object_size
3784 DEFAULT_DOC: no limit
3785 LOC: Config.Store.minObjectSize
3787 Objects smaller than this size will NOT be saved on disk. The
3788 value is specified in bytes, and the default is 0 KB, which
3789 means all responses can be stored.
3792 NAME: maximum_object_size
3796 LOC: Config.Store.maxObjectSize
3798 Set the default value for max-size parameter on any cache_dir.
3799 The value is specified in bytes, and the default is 4 MB.
3801 If you wish to get a high BYTES hit ratio, you should probably
3802 increase this (one 32 MB object hit counts for 3200 10KB
3805 If you wish to increase hit ratio more than you want to
3806 save bandwidth you should leave this low.
3808 NOTE: if using the LFUDA replacement policy you should increase
3809 this value to maximize the byte hit rate improvement of LFUDA!
3810 See cache_replacement_policy for a discussion of this policy.
3816 DEFAULT_DOC: No disk cache. Store cache ojects only in memory.
3817 LOC: Config.cacheSwap
3820 cache_dir Type Directory-Name Fs-specific-data [options]
3822 You can specify multiple cache_dir lines to spread the
3823 cache among different disk partitions.
3825 Type specifies the kind of storage system to use. Only "ufs"
3826 is built by default. To enable any of the other storage systems
3827 see the --enable-storeio configure option.
3829 'Directory' is a top-level directory where cache swap
3830 files will be stored. If you want to use an entire disk
3831 for caching, this can be the mount-point directory.
3832 The directory must exist and be writable by the Squid
3833 process. Squid will NOT create this directory for you.
3835 In SMP configurations, cache_dir must not precede the workers option
3836 and should use configuration macros or conditionals to give each
3837 worker interested in disk caching a dedicated cache directory.
3840 ==== The ufs store type ====
3842 "ufs" is the old well-known Squid storage format that has always
3846 cache_dir ufs Directory-Name Mbytes L1 L2 [options]
3848 'Mbytes' is the amount of disk space (MB) to use under this
3849 directory. The default is 100 MB. Change this to suit your
3850 configuration. Do NOT put the size of your disk drive here.
3851 Instead, if you want Squid to use the entire disk drive,
3852 subtract 20% and use that value.
3854 'L1' is the number of first-level subdirectories which
3855 will be created under the 'Directory'. The default is 16.
3857 'L2' is the number of second-level subdirectories which
3858 will be created under each first-level directory. The default
3862 ==== The aufs store type ====
3864 "aufs" uses the same storage format as "ufs", utilizing
3865 POSIX-threads to avoid blocking the main Squid process on
3866 disk-I/O. This was formerly known in Squid as async-io.
3869 cache_dir aufs Directory-Name Mbytes L1 L2 [options]
3871 see argument descriptions under ufs above
3874 ==== The diskd store type ====
3876 "diskd" uses the same storage format as "ufs", utilizing a
3877 separate process to avoid blocking the main Squid process on
3881 cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n]
3883 see argument descriptions under ufs above
3885 Q1 specifies the number of unacknowledged I/O requests when Squid
3886 stops opening new files. If this many messages are in the queues,
3887 Squid won't open new files. Default is 64
3889 Q2 specifies the number of unacknowledged messages when Squid
3890 starts blocking. If this many messages are in the queues,
3891 Squid blocks until it receives some replies. Default is 72
3893 When Q1 < Q2 (the default), the cache directory is optimized
3894 for lower response time at the expense of a decrease in hit
3895 ratio. If Q1 > Q2, the cache directory is optimized for
3896 higher hit ratio at the expense of an increase in response
3900 ==== The rock store type ====
3903 cache_dir rock Directory-Name Mbytes [options]
3905 The Rock Store type is a database-style storage. All cached
3906 entries are stored in a "database" file, using fixed-size slots.
3907 A single entry occupies one or more slots.
3909 If possible, Squid using Rock Store creates a dedicated kid
3910 process called "disker" to avoid blocking Squid worker(s) on disk
3911 I/O. One disker kid is created for each rock cache_dir. Diskers
3912 are created only when Squid, running in daemon mode, has support
3913 for the IpcIo disk I/O module.
3915 swap-timeout=msec: Squid will not start writing a miss to or
3916 reading a hit from disk if it estimates that the swap operation
3917 will take more than the specified number of milliseconds. By
3918 default and when set to zero, disables the disk I/O time limit
3919 enforcement. Ignored when using blocking I/O module because
3920 blocking synchronous I/O does not allow Squid to estimate the
3921 expected swap wait time.
3923 max-swap-rate=swaps/sec: Artificially limits disk access using
3924 the specified I/O rate limit. Swap out requests that
3925 would cause the average I/O rate to exceed the limit are
3926 delayed. Individual swap in requests (i.e., hits or reads) are
3927 not delayed, but they do contribute to measured swap rate and
3928 since they are placed in the same FIFO queue as swap out
3929 requests, they may wait longer if max-swap-rate is smaller.
3930 This is necessary on file systems that buffer "too
3931 many" writes and then start blocking Squid and other processes
3932 while committing those writes to disk. Usually used together
3933 with swap-timeout to avoid excessive delays and queue overflows
3934 when disk demand exceeds available disk "bandwidth". By default
3935 and when set to zero, disables the disk I/O rate limit
3936 enforcement. Currently supported by IpcIo module only.
3938 slot-size=bytes: The size of a database "record" used for
3939 storing cached responses. A cached response occupies at least
3940 one slot and all database I/O is done using individual slots so
3941 increasing this parameter leads to more disk space waste while
3942 decreasing it leads to more disk I/O overheads. Should be a
3943 multiple of your operating system I/O page size. Defaults to
3944 16KBytes. A housekeeping header is stored with each slot and
3945 smaller slot-sizes will be rejected. The header is smaller than
3949 ==== COMMON OPTIONS ====
3951 no-store no new objects should be stored to this cache_dir.
3953 min-size=n the minimum object size in bytes this cache_dir
3954 will accept. It's used to restrict a cache_dir
3955 to only store large objects (e.g. AUFS) while
3956 other stores are optimized for smaller objects
3960 max-size=n the maximum object size in bytes this cache_dir
3962 The value in maximum_object_size directive sets
3963 the default unless more specific details are
3964 available (ie a small store capacity).
3966 Note: To make optimal use of the max-size limits you should order
3967 the cache_dir lines with the smallest max-size value first.
3971 # Uncomment and adjust the following to add a disk cache directory.
3972 #cache_dir ufs @DEFAULT_SWAP_DIR@ 100 16 256
3976 NAME: store_dir_select_algorithm
3978 LOC: Config.store_dir_select_algorithm
3981 How Squid selects which cache_dir to use when the response
3982 object will fit into more than one.
3984 Regardless of which algorithm is used the cache_dir min-size
3985 and max-size parameters are obeyed. As such they can affect
3986 the selection algorithm by limiting the set of considered
3993 This algorithm is suited to caches with similar cache_dir
3994 sizes and disk speeds.
3996 The disk with the least I/O pending is selected.
3997 When there are multiple disks with the same I/O load ranking
3998 the cache_dir with most available capacity is selected.
4000 When a mix of cache_dir sizes are configured the faster disks
4001 have a naturally lower I/O loading and larger disks have more
4002 capacity. So space used to store objects and data throughput
4003 may be very unbalanced towards larger disks.
4008 This algorithm is suited to caches with unequal cache_dir
4011 Each cache_dir is selected in a rotation. The next suitable
4014 Available cache_dir capacity is only considered in relation
4015 to whether the object will fit and meets the min-size and
4016 max-size parameters.
4018 Disk I/O loading is only considered to prevent overload on slow
4019 disks. This algorithm does not spread objects by size, so any
4020 I/O loading per-disk may appear very unbalanced and volatile.
4022 If several cache_dirs use similar min-size, max-size, or other
4023 limits to to reject certain responses, then do not group such
4024 cache_dir lines together, to avoid round-robin selection bias
4025 towards the first cache_dir after the group. Instead, interleave
4026 cache_dir lines from different groups. For example:
4028 store_dir_select_algorithm round-robin
4029 cache_dir rock /hdd1 ... min-size=100000
4030 cache_dir rock /ssd1 ... max-size=99999
4031 cache_dir rock /hdd2 ... min-size=100000
4032 cache_dir rock /ssd2 ... max-size=99999
4033 cache_dir rock /hdd3 ... min-size=100000
4034 cache_dir rock /ssd3 ... max-size=99999
4037 NAME: max_open_disk_fds
4039 LOC: Config.max_open_disk_fds
4041 DEFAULT_DOC: no limit
4043 To avoid having disk as the I/O bottleneck Squid can optionally
4044 bypass the on-disk cache if more than this amount of disk file
4045 descriptors are open.
4047 A value of 0 indicates no limit.
4050 NAME: cache_swap_low
4051 COMMENT: (percent, 0-100)
4054 LOC: Config.Swap.lowWaterMark
4056 The low-water mark for AUFS/UFS/diskd cache object eviction by
4057 the cache_replacement_policy algorithm.
4059 Removal begins when the swap (disk) usage of a cache_dir is
4060 above this low-water mark and attempts to maintain utilization
4061 near the low-water mark.
4063 As swap utilization increases towards the high-water mark set
4064 by cache_swap_high object eviction becomes more agressive.
4066 The value difference in percentages between low- and high-water
4067 marks represent an eviction rate of 300 objects per second and
4068 the rate continues to scale in agressiveness by multiples of
4069 this above the high-water mark.
4071 Defaults are 90% and 95%. If you have a large cache, 5% could be
4072 hundreds of MB. If this is the case you may wish to set these
4073 numbers closer together.
4075 See also cache_swap_high and cache_replacement_policy
4078 NAME: cache_swap_high
4079 COMMENT: (percent, 0-100)
4082 LOC: Config.Swap.highWaterMark
4084 The high-water mark for AUFS/UFS/diskd cache object eviction by
4085 the cache_replacement_policy algorithm.
4087 Removal begins when the swap (disk) usage of a cache_dir is
4088 above the low-water mark set by cache_swap_low and attempts to
4089 maintain utilization near the low-water mark.
4091 As swap utilization increases towards this high-water mark object
4092 eviction becomes more agressive.
4094 The value difference in percentages between low- and high-water
4095 marks represent an eviction rate of 300 objects per second and
4096 the rate continues to scale in agressiveness by multiples of
4097 this above the high-water mark.
4099 Defaults are 90% and 95%. If you have a large cache, 5% could be
4100 hundreds of MB. If this is the case you may wish to set these
4101 numbers closer together.
4103 See also cache_swap_low and cache_replacement_policy
4108 -----------------------------------------------------------------------------
4115 DEFAULT_DOC: The format definitions squid, common, combined, referrer, useragent are built in.
4119 logformat <name> <format specification>
4121 Defines an access log format.
4123 The <format specification> is a string with embedded % format codes
4125 % format codes all follow the same basic structure where all but
4126 the formatcode is optional. Output strings are automatically escaped
4127 as required according to their context and the output format
4128 modifiers are usually not needed, but can be specified if an explicit
4129 output format is desired.
4131 % ["|[|'|#|/] [-] [[0]width] [{arg}] formatcode [{arg}]
4133 " output in quoted string format
4134 [ output in squid text log format as used by log_mime_hdrs
4135 # output in URL quoted format
4136 / output in shell \-escaped format
4141 width minimum and/or maximum field width:
4142 [width_min][.width_max]
4143 When minimum starts with 0, the field is zero-padded.
4144 String values exceeding maximum width are truncated.
4146 {arg} argument such as header name etc. This field may be
4147 placed before or after the token, but not both at once.
4151 % a literal % character
4152 sn Unique sequence number per log line entry
4153 err_code The ID of an error response served by Squid or
4154 a similar internal error identifier.
4155 err_detail Additional err_code-dependent error information.
4156 note The annotation specified by the argument. Also
4157 logs the adaptation meta headers set by the
4158 adaptation_meta configuration parameter.
4159 If no argument given all annotations logged.
4160 The argument may include a separator to use with
4163 By default, multiple note values are separated with ","
4164 and multiple notes are separated with "\r\n".
4165 When logging named notes with %{name}note, the
4166 explicitly configured separator is used between note
4167 values. When logging all notes with %note, the
4168 explicitly configured separator is used between
4169 individual notes. There is currently no way to
4170 specify both value and notes separators when logging
4171 all notes with %note.
4173 Connection related format codes:
4175 >a Client source IP address
4177 >p Client source port
4178 >eui Client source EUI (MAC address, EUI-48 or EUI-64 identifier)
4179 >la Local IP address the client connected to
4180 >lp Local port number the client connected to
4181 >qos Client connection TOS/DSCP value set by Squid
4182 >nfmark Client connection netfilter mark set by Squid
4184 la Local listening IP address the client connection was connected to.
4185 lp Local listening port number the client connection was connected to.
4187 <a Server IP address of the last server or peer connection
4188 <A Server FQDN or peer name
4189 <p Server port number of the last server or peer connection
4190 <la Local IP address of the last server or peer connection
4191 <lp Local port number of the last server or peer connection
4192 <qos Server connection TOS/DSCP value set by Squid
4193 <nfmark Server connection netfilter mark set by Squid
4195 Time related format codes:
4197 ts Seconds since epoch
4198 tu subsecond time (milliseconds)
4199 tl Local time. Optional strftime format argument
4200 default %d/%b/%Y:%H:%M:%S %z
4201 tg GMT time. Optional strftime format argument
4202 default %d/%b/%Y:%H:%M:%S %z
4203 tr Response time (milliseconds)
4204 dt Total time spent making DNS lookups (milliseconds)
4205 tS Approximate master transaction start time in
4206 <full seconds since epoch>.<fractional seconds> format.
4207 Currently, Squid considers the master transaction
4208 started when a complete HTTP request header initiating
4209 the transaction is received from the client. This is
4210 the same value that Squid uses to calculate transaction
4211 response time when logging %tr to access.log. Currently,
4212 Squid uses millisecond resolution for %tS values,
4213 similar to the default access.log "current time" field
4216 Access Control related format codes:
4218 et Tag returned by external acl
4219 ea Log string returned by external acl
4220 un User name (any available)
4221 ul User name from authentication
4222 ue User name from external acl helper
4223 ui User name from ident
4224 un A user name. Expands to the first available name
4225 from the following list of information sources:
4226 - authenticated user name, like %ul
4227 - user name supplied by an external ACL, like %ue
4228 - SSL client name, like %us
4229 - ident user name, like %ui
4230 credentials Client credentials. The exact meaning depends on
4231 the authentication scheme: For Basic authentication,
4232 it is the password; for Digest, the realm sent by the
4233 client; for NTLM and Negotiate, the client challenge
4234 or client credentials prefixed with "YR " or "KK ".
4236 HTTP related format codes:
4240 [http::]rm Request method (GET/POST etc)
4241 [http::]>rm Request method from client
4242 [http::]<rm Request method sent to server or peer
4243 [http::]ru Request URL from client (historic, filtered for logging)
4244 [http::]>ru Request URL from client
4245 [http::]<ru Request URL sent to server or peer
4246 [http::]>rs Request URL scheme from client
4247 [http::]<rs Request URL scheme sent to server or peer
4248 [http::]>rd Request URL domain from client
4249 [http::]<rd Request URL domain sent to server or peer
4250 [http::]>rP Request URL port from client
4251 [http::]<rP Request URL port sent to server or peer
4252 [http::]rp Request URL path excluding hostname
4253 [http::]>rp Request URL path excluding hostname from client
4254 [http::]<rp Request URL path excluding hostname sent to server or peer
4255 [http::]rv Request protocol version
4256 [http::]>rv Request protocol version from client
4257 [http::]<rv Request protocol version sent to server or peer
4259 [http::]>h Original received request header.
4260 Usually differs from the request header sent by
4261 Squid, although most fields are often preserved.
4262 Accepts optional header field name/value filter
4263 argument using name[:[separator]element] format.
4264 [http::]>ha Received request header after adaptation and
4265 redirection (pre-cache REQMOD vectoring point).
4266 Usually differs from the request header sent by
4267 Squid, although most fields are often preserved.
4268 Optional header name argument as for >h
4272 [http::]<Hs HTTP status code received from the next hop
4273 [http::]>Hs HTTP status code sent to the client
4275 [http::]<h Reply header. Optional header name argument
4278 [http::]mt MIME content type
4283 [http::]st Total size of request + reply traffic with client
4284 [http::]>st Total size of request received from client.
4285 Excluding chunked encoding bytes.
4286 [http::]<st Total size of reply sent to client (after adaptation)
4288 [http::]>sh Size of request headers received from client
4289 [http::]<sh Size of reply headers sent to client (after adaptation)
4291 [http::]<sH Reply high offset sent
4292 [http::]<sS Upstream object size
4294 [http::]<bs Number of HTTP-equivalent message body bytes
4295 received from the next hop, excluding chunked
4296 transfer encoding and control messages.
4297 Generated FTP/Gopher listings are treated as
4302 [http::]<pt Peer response time in milliseconds. The timer starts
4303 when the last request byte is sent to the next hop
4304 and stops when the last response byte is received.
4305 [http::]<tt Total time in milliseconds. The timer
4306 starts with the first connect request (or write I/O)
4307 sent to the first selected peer. The timer stops
4308 with the last I/O with the last peer.
4310 Squid handling related format codes:
4312 Ss Squid request status (TCP_MISS etc)
4313 Sh Squid hierarchy status (DEFAULT_PARENT etc)
4315 SSL-related format codes:
4317 ssl::bump_mode SslBump decision for the transaction:
4319 For CONNECT requests that initiated bumping of
4320 a connection and for any request received on
4321 an already bumped connection, Squid logs the
4322 corresponding SslBump mode ("server-first" or
4323 "client-first"). See the ssl_bump option for
4324 more information about these modes.
4326 A "none" token is logged for requests that
4327 triggered "ssl_bump" ACL evaluation matching
4328 either a "none" rule or no rules at all.
4330 In all other cases, a single dash ("-") is
4333 ssl::>sni SSL client SNI sent to Squid. Available only
4334 after the peek, stare, or splice SSL bumping
4338 The Subject field of the received client
4339 SSL certificate or a dash ('-') if Squid has
4340 received an invalid/malformed certificate or
4341 no certificate at all. Consider encoding the
4342 logged value because Subject often has spaces.
4345 The Issuer field of the received client
4346 SSL certificate or a dash ('-') if Squid has
4347 received an invalid/malformed certificate or
4348 no certificate at all. Consider encoding the
4349 logged value because Issuer often has spaces.
4352 The list of certificate validation errors
4353 detected by Squid (including OpenSSL and
4354 certificate validation helper components). The
4355 errors are listed in the discovery order. By
4356 default, the error codes are separated by ':'.
4357 Accepts an optional separator argument.
4359 %ssl::>negotiated_version The negotiated TLS version of the
4362 %ssl::<negotiated_version The negotiated TLS version of the
4363 last server or peer connection.
4365 %ssl::>received_hello_version The TLS version of the Hello
4366 message received from TLS client.
4368 %ssl::<received_hello_version The TLS version of the Hello
4369 message received from TLS server.
4371 %ssl::>received_supported_version The maximum TLS version
4372 supported by the TLS client.
4374 %ssl::<received_supported_version The maximum TLS version
4375 supported by the TLS server.
4377 %ssl::>negotiated_cipher The negotiated cipher of the
4380 %ssl::<negotiated_cipher The negotiated cipher of the
4381 last server or peer connection.
4383 If ICAP is enabled, the following code becomes available (as
4384 well as ICAP log codes documented with the icap_log option):
4386 icap::tt Total ICAP processing time for the HTTP
4387 transaction. The timer ticks when ICAP
4388 ACLs are checked and when ICAP
4389 transaction is in progress.
4391 If adaptation is enabled the following codes become available:
4393 adapt::<last_h The header of the last ICAP response or
4394 meta-information from the last eCAP
4395 transaction related to the HTTP transaction.
4396 Like <h, accepts an optional header name
4399 adapt::sum_trs Summed adaptation transaction response
4400 times recorded as a comma-separated list in
4401 the order of transaction start time. Each time
4402 value is recorded as an integer number,
4403 representing response time of one or more
4404 adaptation (ICAP or eCAP) transaction in
4405 milliseconds. When a failed transaction is
4406 being retried or repeated, its time is not
4407 logged individually but added to the
4408 replacement (next) transaction. See also:
4411 adapt::all_trs All adaptation transaction response times.
4412 Same as adaptation_strs but response times of
4413 individual transactions are never added
4414 together. Instead, all transaction response
4415 times are recorded individually.
4417 You can prefix adapt::*_trs format codes with adaptation
4418 service name in curly braces to record response time(s) specific
4419 to that service. For example: %{my_service}adapt::sum_trs
4421 The default formats available (which do not need re-defining) are:
4423 logformat squid %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %[un %Sh/%<a %mt
4424 logformat common %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st %Ss:%Sh
4425 logformat combined %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
4426 logformat referrer %ts.%03tu %>a %{Referer}>h %ru
4427 logformat useragent %>a [%tl] "%{User-Agent}>h"
4429 NOTE: When the log_mime_hdrs directive is set to ON.
4430 The squid, common and combined formats have a safely encoded copy
4431 of the mime headers appended to each line within a pair of brackets.
4433 NOTE: The common and combined formats are not quite true to the Apache definition.
4434 The logs from Squid contain an extra status and hierarchy code appended.
4438 NAME: access_log cache_access_log
4440 LOC: Config.Log.accesslogs
4441 DEFAULT_IF_NONE: daemon:@DEFAULT_ACCESS_LOG@ squid
4443 Configures whether and how Squid logs HTTP and ICP transactions.
4444 If access logging is enabled, a single line is logged for every
4445 matching HTTP or ICP request. The recommended directive formats are:
4447 access_log <module>:<place> [option ...] [acl acl ...]
4448 access_log none [acl acl ...]
4450 The following directive format is accepted but may be deprecated:
4451 access_log <module>:<place> [<logformat name> [acl acl ...]]
4453 In most cases, the first ACL name must not contain the '=' character
4454 and should not be equal to an existing logformat name. You can always
4455 start with an 'all' ACL to work around those restrictions.
4457 Will log to the specified module:place using the specified format (which
4458 must be defined in a logformat directive) those entries which match
4459 ALL the acl's specified (which must be defined in acl clauses).
4460 If no acl is specified, all requests will be logged to this destination.
4462 ===== Available options for the recommended directive format =====
4464 logformat=name Names log line format (either built-in or
4465 defined by a logformat directive). Defaults
4468 buffer-size=64KB Defines approximate buffering limit for log
4469 records (see buffered_logs). Squid should not
4470 keep more than the specified size and, hence,
4471 should flush records before the buffer becomes
4472 full to avoid overflows under normal
4473 conditions (the exact flushing algorithm is
4474 module-dependent though). The on-error option
4475 controls overflow handling.
4477 on-error=die|drop Defines action on unrecoverable errors. The
4478 'drop' action ignores (i.e., does not log)
4479 affected log records. The default 'die' action
4480 kills the affected worker. The drop action
4481 support has not been tested for modules other
4484 rotate=N Specifies the number of log file rotations to
4485 make when you run 'squid -k rotate'. The default
4486 is to obey the logfile_rotate directive. Setting
4487 rotate=0 will disable the file name rotation,
4488 but the log files are still closed and re-opened.
4489 This will enable you to rename the logfiles
4490 yourself just before sending the rotate signal.
4491 Only supported by the stdio module.
4493 ===== Modules Currently available =====
4495 none Do not log any requests matching these ACL.
4496 Do not specify Place or logformat name.
4498 stdio Write each log line to disk immediately at the completion of
4500 Place: the filename and path to be written.
4502 daemon Very similar to stdio. But instead of writing to disk the log
4503 line is passed to a daemon helper for asychronous handling instead.
4504 Place: varies depending on the daemon.
4506 log_file_daemon Place: the file name and path to be written.
4508 syslog To log each request via syslog facility.
4509 Place: The syslog facility and priority level for these entries.
4510 Place Format: facility.priority
4512 where facility could be any of:
4513 authpriv, daemon, local0 ... local7 or user.
4515 And priority could be any of:
4516 err, warning, notice, info, debug.
4518 udp To send each log line as text data to a UDP receiver.
4519 Place: The destination host name or IP and port.
4520 Place Format: //host:port
4522 tcp To send each log line as text data to a TCP receiver.
4523 Lines may be accumulated before sending (see buffered_logs).
4524 Place: The destination host name or IP and port.
4525 Place Format: //host:port
4528 access_log daemon:@DEFAULT_ACCESS_LOG@ squid
4534 LOC: Config.Log.icaplogs
4537 ICAP log files record ICAP transaction summaries, one line per
4540 The icap_log option format is:
4541 icap_log <filepath> [<logformat name> [acl acl ...]]
4542 icap_log none [acl acl ...]]
4544 Please see access_log option documentation for details. The two
4545 kinds of logs share the overall configuration approach and many
4548 ICAP processing of a single HTTP message or transaction may
4549 require multiple ICAP transactions. In such cases, multiple
4550 ICAP transaction log lines will correspond to a single access
4553 ICAP log supports many access.log logformat %codes. In ICAP context,
4554 HTTP message-related %codes are applied to the HTTP message embedded
4555 in an ICAP message. Logformat "%http::>..." codes are used for HTTP
4556 messages embedded in ICAP requests while "%http::<..." codes are used
4557 for HTTP messages embedded in ICAP responses. For example:
4559 http::>h To-be-adapted HTTP message headers sent by Squid to
4560 the ICAP service. For REQMOD transactions, these are
4561 HTTP request headers. For RESPMOD, these are HTTP
4562 response headers, but Squid currently cannot log them
4563 (i.e., %http::>h will expand to "-" for RESPMOD).
4565 http::<h Adapted HTTP message headers sent by the ICAP
4566 service to Squid (i.e., HTTP request headers in regular
4567 REQMOD; HTTP response headers in RESPMOD and during
4568 request satisfaction in REQMOD).
4570 ICAP OPTIONS transactions do not embed HTTP messages.
4572 Several logformat codes below deal with ICAP message bodies. An ICAP
4573 message body, if any, typically includes a complete HTTP message
4574 (required HTTP headers plus optional HTTP message body). When
4575 computing HTTP message body size for these logformat codes, Squid
4576 either includes or excludes chunked encoding overheads; see
4577 code-specific documentation for details.
4579 For Secure ICAP services, all size-related information is currently
4580 computed before/after TLS encryption/decryption, as if TLS was not
4583 The following format codes are also available for ICAP logs:
4585 icap::<A ICAP server IP address. Similar to <A.
4587 icap::<service_name ICAP service name from the icap_service
4588 option in Squid configuration file.
4590 icap::ru ICAP Request-URI. Similar to ru.
4592 icap::rm ICAP request method (REQMOD, RESPMOD, or
4593 OPTIONS). Similar to existing rm.
4595 icap::>st The total size of the ICAP request sent to the ICAP
4596 server (ICAP headers + ICAP body), including chunking
4599 icap::<st The total size of the ICAP response received from the
4600 ICAP server (ICAP headers + ICAP body), including
4601 chunking metadata (if any).
4603 icap::<bs The size of the ICAP response body received from the
4604 ICAP server, excluding chunking metadata (if any).
4606 icap::tr Transaction response time (in
4607 milliseconds). The timer starts when
4608 the ICAP transaction is created and
4609 stops when the transaction is completed.
4612 icap::tio Transaction I/O time (in milliseconds). The
4613 timer starts when the first ICAP request
4614 byte is scheduled for sending. The timers
4615 stops when the last byte of the ICAP response
4618 icap::to Transaction outcome: ICAP_ERR* for all
4619 transaction errors, ICAP_OPT for OPTION
4620 transactions, ICAP_ECHO for 204
4621 responses, ICAP_MOD for message
4622 modification, and ICAP_SAT for request
4623 satisfaction. Similar to Ss.
4625 icap::Hs ICAP response status code. Similar to Hs.
4627 icap::>h ICAP request header(s). Similar to >h.
4629 icap::<h ICAP response header(s). Similar to <h.
4631 The default ICAP log format, which can be used without an explicit
4632 definition, is called icap_squid:
4634 logformat icap_squid %ts.%03tu %6icap::tr %>A %icap::to/%03icap::Hs %icap::<st %icap::rm %icap::ru %un -/%icap::<A -
4636 See also: logformat and %adapt::<last_h
4639 NAME: logfile_daemon
4641 DEFAULT: @DEFAULT_LOGFILED@
4642 LOC: Log::TheConfig.logfile_daemon
4644 Specify the path to the logfile-writing daemon. This daemon is
4645 used to write the access and store logs, if configured.
4647 Squid sends a number of commands to the log daemon:
4648 L<data>\n - logfile data
4653 r<n>\n - set rotate count to <n>
4654 b<n>\n - 1 = buffer output, 0 = don't buffer output
4656 No responses is expected.
4659 NAME: stats_collection
4661 LOC: Config.accessList.stats_collection
4663 DEFAULT_DOC: Allow logging for all transactions.
4664 COMMENT: allow|deny acl acl...
4666 This options allows you to control which requests gets accounted
4667 in performance counters.
4669 This clause only supports fast acl types.
4670 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4673 NAME: cache_store_log
4676 LOC: Config.Log.store
4678 Logs the activities of the storage manager. Shows which
4679 objects are ejected from the cache, and which objects are
4680 saved and for how long.
4681 There are not really utilities to analyze this data, so you can safely
4682 disable it (the default).
4684 Store log uses modular logging outputs. See access_log for the list
4685 of modules supported.
4688 cache_store_log stdio:@DEFAULT_STORE_LOG@
4689 cache_store_log daemon:@DEFAULT_STORE_LOG@
4692 NAME: cache_swap_state cache_swap_log
4694 LOC: Config.Log.swap
4696 DEFAULT_DOC: Store the journal inside its cache_dir
4698 Location for the cache "swap.state" file. This index file holds
4699 the metadata of objects saved on disk. It is used to rebuild
4700 the cache during startup. Normally this file resides in each
4701 'cache_dir' directory, but you may specify an alternate
4702 pathname here. Note you must give a full filename, not just
4703 a directory. Since this is the index for the whole object
4704 list you CANNOT periodically rotate it!
4706 If %s can be used in the file name it will be replaced with a
4707 a representation of the cache_dir name where each / is replaced
4708 with '.'. This is needed to allow adding/removing cache_dir
4709 lines when cache_swap_log is being used.
4711 If have more than one 'cache_dir', and %s is not used in the name
4712 these swap logs will have names such as:
4718 The numbered extension (which is added automatically)
4719 corresponds to the order of the 'cache_dir' lines in this
4720 configuration file. If you change the order of the 'cache_dir'
4721 lines in this file, these index files will NOT correspond to
4722 the correct 'cache_dir' entry (unless you manually rename
4723 them). We recommend you do NOT use this option. It is
4724 better to keep these index files in each 'cache_dir' directory.
4727 NAME: logfile_rotate
4730 LOC: Config.Log.rotateNumber
4732 Specifies the default number of logfile rotations to make when you
4733 type 'squid -k rotate'. The default is 10, which will rotate
4734 with extensions 0 through 9. Setting logfile_rotate to 0 will
4735 disable the file name rotation, but the logfiles are still closed
4736 and re-opened. This will enable you to rename the logfiles
4737 yourself just before sending the rotate signal.
4739 Note, from Squid-3.1 this option is only a default for cache.log,
4740 that log can be rotated separately by using debug_options.
4742 Note, from Squid-3.6 this option is only a default for access.log
4743 recorded by stdio: module. Those logs can be rotated separately by
4744 using the rotate=N option on their access_log directive.
4746 Note, the 'squid -k rotate' command normally sends a USR1
4747 signal to the running squid process. In certain situations
4748 (e.g. on Linux with Async I/O), USR1 is used for other
4749 purposes, so -k rotate uses another signal. It is best to get
4750 in the habit of using 'squid -k rotate' instead of 'kill -USR1
4757 DEFAULT: @DEFAULT_MIME_TABLE@
4758 LOC: Config.mimeTablePathname
4760 Path to Squid's icon configuration file.
4762 You shouldn't need to change this, but the default file contains
4763 examples and formatting information if you do.
4769 LOC: Config.onoff.log_mime_hdrs
4772 The Cache can record both the request and the response MIME
4773 headers for each HTTP transaction. The headers are encoded
4774 safely and will appear as two bracketed fields at the end of
4775 the access log (for either the native or httpd-emulated log
4776 formats). To enable this logging set log_mime_hdrs to 'on'.
4781 DEFAULT: @DEFAULT_PID_FILE@
4782 LOC: Config.pidFilename
4784 A filename to write the process-id to. To disable, enter "none".
4787 NAME: client_netmask
4789 LOC: Config.Addrs.client_netmask
4791 DEFAULT_DOC: Log full client IP address
4793 A netmask for client addresses in logfiles and cachemgr output.
4794 Change this to protect the privacy of your cache clients.
4795 A netmask of 255.255.255.0 will log all IP's in that range with
4796 the last digit set to '0'.
4799 NAME: strip_query_terms
4801 LOC: Config.onoff.strip_query_terms
4804 By default, Squid strips query terms from requested URLs before
4805 logging. This protects your user's privacy and reduces log size.
4807 When investigating HIT/MISS or other caching behaviour you
4808 will need to disable this to see the full URL used by Squid.
4815 LOC: Config.onoff.buffered_logs
4817 Whether to write/send access_log records ASAP or accumulate them and
4818 then write/send them in larger chunks. Buffering may improve
4819 performance because it decreases the number of I/Os. However,
4820 buffering increases the delay before log records become available to
4821 the final recipient (e.g., a disk file or logging daemon) and,
4822 hence, increases the risk of log records loss.
4824 Note that even when buffered_logs are off, Squid may have to buffer
4825 records if it cannot write/send them immediately due to pending I/Os
4826 (e.g., the I/O writing the previous log record) or connectivity loss.
4828 Currently honored by 'daemon' and 'tcp' access_log modules only.
4831 NAME: netdb_filename
4833 DEFAULT: stdio:@DEFAULT_NETDB_FILE@
4834 LOC: Config.netdbFilename
4837 Where Squid stores it's netdb journal.
4838 When enabled this journal preserves netdb state between restarts.
4840 To disable, enter "none".
4844 OPTIONS FOR TROUBLESHOOTING
4845 -----------------------------------------------------------------------------
4850 DEFAULT_IF_NONE: @DEFAULT_CACHE_LOG@
4851 LOC: Debug::cache_log
4853 Squid administrative logging file.
4855 This is where general information about Squid behavior goes. You can
4856 increase the amount of data logged to this file and how often it is
4857 rotated with "debug_options"
4863 DEFAULT_DOC: Log all critical and important messages.
4864 LOC: Debug::debugOptions
4866 Logging options are set as section,level where each source file
4867 is assigned a unique section. Lower levels result in less
4868 output, Full debugging (level 9) can result in a very large
4869 log file, so be careful.
4871 The magic word "ALL" sets debugging levels for all sections.
4872 The default is to run with "ALL,1" to record important warnings.
4874 The rotate=N option can be used to keep more or less of these logs
4875 than would otherwise be kept by logfile_rotate.
4876 For most uses a single log should be enough to monitor current
4877 events affecting Squid.
4882 LOC: Config.coredump_dir
4883 DEFAULT_IF_NONE: none
4884 DEFAULT_DOC: Use the directory from where Squid was started.
4886 By default Squid leaves core files in the directory from where
4887 it was started. If you set 'coredump_dir' to a directory
4888 that exists, Squid will chdir() to that directory at startup
4889 and coredump files will be left there.
4893 # Leave coredumps in the first cache dir
4894 coredump_dir @DEFAULT_SWAP_DIR@
4900 OPTIONS FOR FTP GATEWAYING
4901 -----------------------------------------------------------------------------
4907 LOC: Config.Ftp.anon_user
4909 If you want the anonymous login password to be more informative
4910 (and enable the use of picky FTP servers), set this to something
4911 reasonable for your domain, like wwwuser@somewhere.net
4913 The reason why this is domainless by default is the
4914 request can be made on the behalf of a user in any domain,
4915 depending on how the cache is used.
4916 Some FTP server also validate the email address is valid
4917 (for example perl.com).
4923 LOC: Config.Ftp.passive
4925 If your firewall does not allow Squid to use passive
4926 connections, turn off this option.
4928 Use of ftp_epsv_all option requires this to be ON.
4934 LOC: Config.Ftp.epsv_all
4936 FTP Protocol extensions permit the use of a special "EPSV ALL" command.
4938 NATs may be able to put the connection on a "fast path" through the
4939 translator, as the EPRT command will never be used and therefore,
4940 translation of the data portion of the segments will never be needed.
4942 When a client only expects to do two-way FTP transfers this may be
4944 If squid finds that it must do a three-way FTP transfer after issuing
4945 an EPSV ALL command, the FTP session will fail.
4947 If you have any doubts about this option do not use it.
4948 Squid will nicely attempt all other connection methods.
4950 Requires ftp_passive to be ON (default) for any effect.
4956 LOC: Config.accessList.ftp_epsv
4958 FTP Protocol extensions permit the use of a special "EPSV" command.
4960 NATs may be able to put the connection on a "fast path" through the
4961 translator using EPSV, as the EPRT command will never be used
4962 and therefore, translation of the data portion of the segments
4963 will never be needed.
4965 EPSV is often required to interoperate with FTP servers on IPv6
4966 networks. On the other hand, it may break some IPv4 servers.
4968 By default, EPSV may try EPSV with any FTP server. To fine tune
4969 that decision, you may restrict EPSV to certain clients or servers
4972 ftp_epsv allow|deny al1 acl2 ...
4974 WARNING: Disabling EPSV may cause problems with external NAT and IPv6.
4976 Only fast ACLs are supported.
4977 Requires ftp_passive to be ON (default) for any effect.
4983 LOC: Config.Ftp.eprt
4985 FTP Protocol extensions permit the use of a special "EPRT" command.
4987 This extension provides a protocol neutral alternative to the
4988 IPv4-only PORT command. When supported it enables active FTP data
4989 channels over IPv6 and efficient NAT handling.
4991 Turning this OFF will prevent EPRT being attempted and will skip
4992 straight to using PORT for IPv4 servers.
4994 Some devices are known to not handle this extension correctly and
4995 may result in crashes. Devices which suport EPRT enough to fail
4996 cleanly will result in Squid attempting PORT anyway. This directive
4997 should only be disabled when EPRT results in device failures.
4999 WARNING: Doing so will convert Squid back to the old behavior with all
5000 the related problems with external NAT devices/layers and IPv4-only FTP.
5003 NAME: ftp_sanitycheck
5006 LOC: Config.Ftp.sanitycheck
5008 For security and data integrity reasons Squid by default performs
5009 sanity checks of the addresses of FTP data connections ensure the
5010 data connection is to the requested server. If you need to allow
5011 FTP connections to servers using another IP address for the data
5012 connection turn this off.
5015 NAME: ftp_telnet_protocol
5018 LOC: Config.Ftp.telnet
5020 The FTP protocol is officially defined to use the telnet protocol
5021 as transport channel for the control connection. However, many
5022 implementations are broken and does not respect this aspect of
5025 If you have trouble accessing files with ASCII code 255 in the
5026 path or similar problems involving this ASCII code you can
5027 try setting this directive to off. If that helps, report to the
5028 operator of the FTP server in question that their FTP server
5029 is broken and does not follow the FTP standard.
5033 OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
5034 -----------------------------------------------------------------------------
5039 DEFAULT: @DEFAULT_DISKD@
5040 LOC: Config.Program.diskd
5042 Specify the location of the diskd executable.
5043 Note this is only useful if you have compiled in
5044 diskd as one of the store io modules.
5047 NAME: unlinkd_program
5050 DEFAULT: @DEFAULT_UNLINKD@
5051 LOC: Config.Program.unlinkd
5053 Specify the location of the executable for file deletion process.
5056 NAME: pinger_program
5059 DEFAULT: @DEFAULT_PINGER@
5062 Specify the location of the executable for the pinger process.
5071 Control whether the pinger is active at run-time.
5072 Enables turning ICMP pinger on and off with a simple
5073 squid -k reconfigure.
5078 OPTIONS FOR URL REWRITING
5079 -----------------------------------------------------------------------------
5082 NAME: url_rewrite_program redirect_program
5084 LOC: Config.Program.redirect
5087 Specify the location of the executable URL rewriter to use.
5088 Since they can perform almost any function there isn't one included.
5090 For each requested URL, the rewriter will receive on line with the format
5092 [channel-ID <SP>] URL [<SP> extras]<NL>
5094 See url_rewrite_extras on how to send "extras" with optional values to
5096 After processing the request the helper must reply using the following format:
5098 [channel-ID <SP>] result [<SP> kv-pairs]
5100 The result code can be:
5102 OK status=30N url="..."
5103 Redirect the URL to the one supplied in 'url='.
5104 'status=' is optional and contains the status code to send
5105 the client in Squids HTTP response. It must be one of the
5106 HTTP redirect status codes: 301, 302, 303, 307, 308.
5107 When no status is given Squid will use 302.
5109 OK rewrite-url="..."
5110 Rewrite the URL to the one supplied in 'rewrite-url='.
5111 The new URL is fetched directly by Squid and returned to
5112 the client as the response to its request.
5115 When neither of url= and rewrite-url= are sent Squid does
5119 Do not change the URL.
5122 An internal error occurred in the helper, preventing
5123 a result being identified. The 'message=' key name is
5124 reserved for delivering a log message.
5127 In addition to the above kv-pairs Squid also understands the following
5128 optional kv-pairs received from URL rewriters:
5130 Associates a TAG with the client TCP connection.
5131 The TAG is treated as a regular annotation but persists across
5132 future requests on the client connection rather than just the
5133 current request. A helper may update the TAG during subsequent
5134 requests be returning a new kv-pair.
5136 When using the concurrency= option the protocol is changed by
5137 introducing a query channel tag in front of the request/response.
5138 The query channel tag is a number between 0 and concurrency-1.
5139 This value must be echoed back unchanged to Squid as the first part
5140 of the response relating to its request.
5142 WARNING: URL re-writing ability should be avoided whenever possible.
5143 Use the URL redirect form of response instead.
5145 Re-write creates a difference in the state held by the client
5146 and server. Possibly causing confusion when the server response
5147 contains snippets of its view state. Embeded URLs, response
5148 and content Location headers, etc. are not re-written by this
5151 By default, a URL rewriter is not used.
5154 NAME: url_rewrite_children redirect_children
5155 TYPE: HelperChildConfig
5156 DEFAULT: 20 startup=0 idle=1 concurrency=0
5157 LOC: Config.redirectChildren
5159 The maximum number of redirector processes to spawn. If you limit
5160 it too few Squid will have to wait for them to process a backlog of
5161 URLs, slowing it down. If you allow too many they will use RAM
5162 and other system resources noticably.
5164 The startup= and idle= options allow some measure of skew in your
5169 Sets a minimum of how many processes are to be spawned when Squid
5170 starts or reconfigures. When set to zero the first request will
5171 cause spawning of the first child process to handle it.
5173 Starting too few will cause an initial slowdown in traffic as Squid
5174 attempts to simultaneously spawn enough processes to cope.
5178 Sets a minimum of how many processes Squid is to try and keep available
5179 at all times. When traffic begins to rise above what the existing
5180 processes can handle this many more will be spawned up to the maximum
5181 configured. A minimum setting of 1 is required.
5185 The number of requests each redirector helper can handle in
5186 parallel. Defaults to 0 which indicates the redirector
5187 is a old-style single threaded redirector.
5189 When this directive is set to a value >= 1 then the protocol
5190 used to communicate with the helper is modified to include
5191 an ID in front of the request/response. The ID from the request
5192 must be echoed back with the response to that request.
5196 Sets the maximum number of queued requests to N. The default maximum
5197 is 2*numberofchildren. If the queued requests exceed queue size and
5198 redirector_bypass configuration option is set, then redirector is bypassed.
5199 Otherwise, Squid is allowed to temporarily exceed the configured maximum,
5200 marking the affected helper as "overloaded". If the helper overload lasts
5201 more than 3 minutes, the action prescribed by the on-persistent-overload
5204 on-persistent-overload=action
5206 Specifies Squid reaction to a new helper request arriving when the helper
5207 has been overloaded for more that 3 minutes already. The number of queued
5208 requests determines whether the helper is overloaded (see the queue-size
5211 Two actions are supported:
5213 die Squid worker quits. This is the default behavior.
5215 ERR Squid treats the helper request as if it was
5216 immediately submitted, and the helper immediately
5217 replied with an ERR response. This action has no effect
5218 on the already queued and in-progress helper requests.
5221 NAME: url_rewrite_host_header redirect_rewrites_host_header
5224 LOC: Config.onoff.redir_rewrites_host
5226 To preserve same-origin security policies in browsers and
5227 prevent Host: header forgery by redirectors Squid rewrites
5228 any Host: header in redirected requests.
5230 If you are running an accelerator this may not be a wanted
5231 effect of a redirector. This directive enables you disable
5232 Host: alteration in reverse-proxy traffic.
5234 WARNING: Entries are cached on the result of the URL rewriting
5235 process, so be careful if you have domain-virtual hosts.
5237 WARNING: Squid and other software verifies the URL and Host
5238 are matching, so be careful not to relay through other proxies
5239 or inspecting firewalls with this disabled.
5242 NAME: url_rewrite_access redirector_access
5245 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
5246 LOC: Config.accessList.redirector
5248 If defined, this access list specifies which requests are
5249 sent to the redirector processes.
5251 This clause supports both fast and slow acl types.
5252 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5255 NAME: url_rewrite_bypass redirector_bypass
5257 LOC: Config.onoff.redirector_bypass
5260 When this is 'on', a request will not go through the
5261 redirector if all the helpers are busy. If this is 'off' and the
5262 redirector queue grows too large, the action is prescribed by the
5263 on-persistent-overload option. You should only enable this if the
5264 redirectors are not critical to your caching system. If you use
5265 redirectors for access control, and you enable this option,
5266 users may have access to pages they should not
5267 be allowed to request.
5268 This options sets default queue-size option of the url_rewrite_children
5272 NAME: url_rewrite_extras
5273 TYPE: TokenOrQuotedString
5274 LOC: Config.redirector_extras
5275 DEFAULT: "%>a/%>A %un %>rm myip=%la myport=%lp"
5277 Specifies a string to be append to request line format for the
5278 rewriter helper. "Quoted" format values may contain spaces and
5279 logformat %macros. In theory, any logformat %macro can be used.
5280 In practice, a %macro expands as a dash (-) if the helper request is
5281 sent before the required macro information is available to Squid.
5284 NAME: url_rewrite_timeout
5285 TYPE: UrlHelperTimeout
5286 LOC: Config.onUrlRewriteTimeout
5288 DEFAULT_DOC: Squid waits for the helper response forever
5290 Squid times active requests to redirector. The timeout value and Squid
5291 reaction to a timed out request are configurable using the following
5294 url_rewrite_timeout timeout time-units on_timeout=<action> [response=<quoted-response>]
5296 supported timeout actions:
5297 fail Squid return a ERR_GATEWAY_FAILURE error page
5299 bypass Do not re-write the URL
5301 retry Send the lookup to the helper again
5303 use_configured_response
5304 Use the <quoted-response> as helper response
5308 OPTIONS FOR STORE ID
5309 -----------------------------------------------------------------------------
5312 NAME: store_id_program storeurl_rewrite_program
5314 LOC: Config.Program.store_id
5317 Specify the location of the executable StoreID helper to use.
5318 Since they can perform almost any function there isn't one included.
5320 For each requested URL, the helper will receive one line with the format
5322 [channel-ID <SP>] URL [<SP> extras]<NL>
5325 After processing the request the helper must reply using the following format:
5327 [channel-ID <SP>] result [<SP> kv-pairs]
5329 The result code can be:
5332 Use the StoreID supplied in 'store-id='.
5335 The default is to use HTTP request URL as the store ID.
5338 An internal error occured in the helper, preventing
5339 a result being identified.
5341 In addition to the above kv-pairs Squid also understands the following
5342 optional kv-pairs received from URL rewriters:
5344 Associates a TAG with the client TCP connection.
5345 Please see url_rewrite_program related documentation for this
5348 Helper programs should be prepared to receive and possibly ignore
5349 additional whitespace-separated tokens on each input line.
5351 When using the concurrency= option the protocol is changed by
5352 introducing a query channel tag in front of the request/response.
5353 The query channel tag is a number between 0 and concurrency-1.
5354 This value must be echoed back unchanged to Squid as the first part
5355 of the response relating to its request.
5357 NOTE: when using StoreID refresh_pattern will apply to the StoreID
5358 returned from the helper and not the URL.
5360 WARNING: Wrong StoreID value returned by a careless helper may result
5361 in the wrong cached response returned to the user.
5363 By default, a StoreID helper is not used.
5366 NAME: store_id_extras
5367 TYPE: TokenOrQuotedString
5368 LOC: Config.storeId_extras
5369 DEFAULT: "%>a/%>A %un %>rm myip=%la myport=%lp"
5371 Specifies a string to be append to request line format for the
5372 StoreId helper. "Quoted" format values may contain spaces and
5373 logformat %macros. In theory, any logformat %macro can be used.
5374 In practice, a %macro expands as a dash (-) if the helper request is
5375 sent before the required macro information is available to Squid.
5378 NAME: store_id_children storeurl_rewrite_children
5379 TYPE: HelperChildConfig
5380 DEFAULT: 20 startup=0 idle=1 concurrency=0
5381 LOC: Config.storeIdChildren
5383 The maximum number of StoreID helper processes to spawn. If you limit
5384 it too few Squid will have to wait for them to process a backlog of
5385 requests, slowing it down. If you allow too many they will use RAM
5386 and other system resources noticably.
5388 The startup= and idle= options allow some measure of skew in your
5393 Sets a minimum of how many processes are to be spawned when Squid
5394 starts or reconfigures. When set to zero the first request will
5395 cause spawning of the first child process to handle it.
5397 Starting too few will cause an initial slowdown in traffic as Squid
5398 attempts to simultaneously spawn enough processes to cope.
5402 Sets a minimum of how many processes Squid is to try and keep available
5403 at all times. When traffic begins to rise above what the existing
5404 processes can handle this many more will be spawned up to the maximum
5405 configured. A minimum setting of 1 is required.
5409 The number of requests each storeID helper can handle in
5410 parallel. Defaults to 0 which indicates the helper
5411 is a old-style single threaded program.
5413 When this directive is set to a value >= 1 then the protocol
5414 used to communicate with the helper is modified to include
5415 an ID in front of the request/response. The ID from the request
5416 must be echoed back with the response to that request.
5420 Sets the maximum number of queued requests to N. The default maximum
5421 is 2*numberofchildren. If the queued requests exceed queue size and
5422 redirector_bypass configuration option is set, then redirector is bypassed.
5423 Otherwise, Squid is allowed to temporarily exceed the configured maximum,
5424 marking the affected helper as "overloaded". If the helper overload lasts
5425 more than 3 minutes, the action prescribed by the on-persistent-overload
5428 on-persistent-overload=action
5430 Specifies Squid reaction to a new helper request arriving when the helper
5431 has been overloaded for more that 3 minutes already. The number of queued
5432 requests determines whether the helper is overloaded (see the queue-size
5435 Two actions are supported:
5437 die Squid worker quits. This is the default behavior.
5439 ERR Squid treats the helper request as if it was
5440 immediately submitted, and the helper immediately
5441 replied with an ERR response. This action has no effect
5442 on the already queued and in-progress helper requests.
5445 NAME: store_id_access storeurl_rewrite_access
5448 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
5449 LOC: Config.accessList.store_id
5451 If defined, this access list specifies which requests are
5452 sent to the StoreID processes. By default all requests
5455 This clause supports both fast and slow acl types.
5456 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5459 NAME: store_id_bypass storeurl_rewrite_bypass
5461 LOC: Config.onoff.store_id_bypass
5464 When this is 'on', a request will not go through the
5465 helper if all helpers are busy. If this is 'off' and the helper
5466 queue grows too large, the action is prescribed by the
5467 on-persistent-overload option. You should only enable this if the
5468 helpers are not critical to your caching system. If you use
5469 helpers for critical caching components, and you enable this
5470 option, users may not get objects from cache.
5471 This options sets default queue-size option of the store_id_children
5476 OPTIONS FOR TUNING THE CACHE
5477 -----------------------------------------------------------------------------
5480 NAME: cache no_cache
5483 DEFAULT_DOC: By default, this directive is unused and has no effect.
5484 LOC: Config.accessList.noCache
5486 Requests denied by this directive will not be served from the cache
5487 and their responses will not be stored in the cache. This directive
5488 has no effect on other transactions and on already cached responses.
5490 This clause supports both fast and slow acl types.
5491 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5493 This and the two other similar caching directives listed below are
5494 checked at different transaction processing stages, have different
5495 access to response information, affect different cache operations,
5496 and differ in slow ACLs support:
5498 * cache: Checked before Squid makes a hit/miss determination.
5499 No access to reply information!
5500 Denies both serving a hit and storing a miss.
5501 Supports both fast and slow ACLs.
5502 * send_hit: Checked after a hit was detected.
5503 Has access to reply (hit) information.
5504 Denies serving a hit only.
5505 Supports fast ACLs only.
5506 * store_miss: Checked before storing a cachable miss.
5507 Has access to reply (miss) information.
5508 Denies storing a miss only.
5509 Supports fast ACLs only.
5511 If you are not sure which of the three directives to use, apply the
5512 following decision logic:
5514 * If your ACL(s) are of slow type _and_ need response info, redesign.
5515 Squid does not support that particular combination at this time.
5517 * If your directive ACL(s) are of slow type, use "cache"; and/or
5518 * if your directive ACL(s) need no response info, use "cache".
5520 * If you do not want the response cached, use store_miss; and/or
5521 * if you do not want a hit on a cached response, use send_hit.
5527 DEFAULT_DOC: By default, this directive is unused and has no effect.
5528 LOC: Config.accessList.sendHit
5530 Responses denied by this directive will not be served from the cache
5531 (but may still be cached, see store_miss). This directive has no
5532 effect on the responses it allows and on the cached objects.
5534 Please see the "cache" directive for a summary of differences among
5535 store_miss, send_hit, and cache directives.
5537 Unlike the "cache" directive, send_hit only supports fast acl
5538 types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5542 # apply custom Store ID mapping to some URLs
5543 acl MapMe dstdomain .c.example.com
5544 store_id_program ...
5545 store_id_access allow MapMe
5547 # but prevent caching of special responses
5548 # such as 302 redirects that cause StoreID loops
5549 acl Ordinary http_status 200-299
5550 store_miss deny MapMe !Ordinary
5552 # and do not serve any previously stored special responses
5553 # from the cache (in case they were already cached before
5554 # the above store_miss rule was in effect).
5555 send_hit deny MapMe !Ordinary
5561 DEFAULT_DOC: By default, this directive is unused and has no effect.
5562 LOC: Config.accessList.storeMiss
5564 Responses denied by this directive will not be cached (but may still
5565 be served from the cache, see send_hit). This directive has no
5566 effect on the responses it allows and on the already cached responses.
5568 Please see the "cache" directive for a summary of differences among
5569 store_miss, send_hit, and cache directives. See the
5570 send_hit directive for a usage example.
5572 Unlike the "cache" directive, store_miss only supports fast acl
5573 types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5579 LOC: Config.maxStale
5582 This option puts an upper limit on how stale content Squid
5583 will serve from the cache if cache validation fails.
5584 Can be overriden by the refresh_pattern max-stale option.
5587 NAME: refresh_pattern
5588 TYPE: refreshpattern
5592 usage: refresh_pattern [-i] regex min percent max [options]
5594 By default, regular expressions are CASE-SENSITIVE. To make
5595 them case-insensitive, use the -i option.
5597 'Min' is the time (in minutes) an object without an explicit
5598 expiry time should be considered fresh. The recommended
5599 value is 0, any higher values may cause dynamic applications
5600 to be erroneously cached unless the application designer
5601 has taken the appropriate actions.
5603 'Percent' is a percentage of the objects age (time since last
5604 modification age) an object without explicit expiry time
5605 will be considered fresh.
5607 'Max' is an upper limit on how long objects without an explicit
5608 expiry time will be considered fresh.
5610 options: override-expire
5620 override-expire enforces min age even if the server
5621 sent an explicit expiry time (e.g., with the
5622 Expires: header or Cache-Control: max-age). Doing this
5623 VIOLATES the HTTP standard. Enabling this feature
5624 could make you liable for problems which it causes.
5626 Note: override-expire does not enforce staleness - it only extends
5627 freshness / min. If the server returns a Expires time which
5628 is longer than your max time, Squid will still consider
5629 the object fresh for that period of time.
5631 override-lastmod enforces min age even on objects
5632 that were modified recently.
5634 reload-into-ims changes a client no-cache or ``reload''
5635 request for a cached entry into a conditional request using
5636 If-Modified-Since and/or If-None-Match headers, provided the
5637 cached entry has a Last-Modified and/or a strong ETag header.
5638 Doing this VIOLATES the HTTP standard. Enabling this feature
5639 could make you liable for problems which it causes.
5641 ignore-reload ignores a client no-cache or ``reload''
5642 header. Doing this VIOLATES the HTTP standard. Enabling
5643 this feature could make you liable for problems which
5646 ignore-no-store ignores any ``Cache-control: no-store''
5647 headers received from a server. Doing this VIOLATES
5648 the HTTP standard. Enabling this feature could make you
5649 liable for problems which it causes.
5651 ignore-private ignores any ``Cache-control: private''
5652 headers received from a server. Doing this VIOLATES
5653 the HTTP standard. Enabling this feature could make you
5654 liable for problems which it causes.
5656 refresh-ims causes squid to contact the origin server
5657 when a client issues an If-Modified-Since request. This
5658 ensures that the client will receive an updated version
5659 if one is available.
5661 store-stale stores responses even if they don't have explicit
5662 freshness or a validator (i.e., Last-Modified or an ETag)
5663 present, or if they're already stale. By default, Squid will
5664 not cache such responses because they usually can't be
5665 reused. Note that such responses will be stale by default.
5667 max-stale=NN provide a maximum staleness factor. Squid won't
5668 serve objects more stale than this even if it failed to
5669 validate the object. Default: use the max_stale global limit.
5671 Basically a cached object is:
5673 FRESH if expire > now, else STALE
5675 FRESH if lm-factor < percent, else STALE
5679 The refresh_pattern lines are checked in the order listed here.
5680 The first entry which matches is used. If none of the entries
5681 match the default will be used.
5683 Note, you must uncomment all the default lines if you want
5684 to change one. The default setting is only active if none is
5690 # Add any of your own refresh_pattern entries above these.
5692 refresh_pattern ^ftp: 1440 20% 10080
5693 refresh_pattern ^gopher: 1440 0% 1440
5694 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0
5695 refresh_pattern . 0 20% 4320
5699 NAME: quick_abort_min
5703 LOC: Config.quickAbort.min
5706 NAME: quick_abort_max
5710 LOC: Config.quickAbort.max
5713 NAME: quick_abort_pct
5717 LOC: Config.quickAbort.pct
5719 The cache by default continues downloading aborted requests
5720 which are almost completed (less than 16 KB remaining). This
5721 may be undesirable on slow (e.g. SLIP) links and/or very busy
5722 caches. Impatient users may tie up file descriptors and
5723 bandwidth by repeatedly requesting and immediately aborting
5726 When the user aborts a request, Squid will check the
5727 quick_abort values to the amount of data transferred until
5730 If the transfer has less than 'quick_abort_min' KB remaining,
5731 it will finish the retrieval.
5733 If the transfer has more than 'quick_abort_max' KB remaining,
5734 it will abort the retrieval.
5736 If more than 'quick_abort_pct' of the transfer has completed,
5737 it will finish the retrieval.
5739 If you do not want any retrieval to continue after the client
5740 has aborted, set both 'quick_abort_min' and 'quick_abort_max'
5743 If you want retrievals to always continue if they are being
5744 cached set 'quick_abort_min' to '-1 KB'.
5747 NAME: read_ahead_gap
5748 COMMENT: buffer-size
5750 LOC: Config.readAheadGap
5753 The amount of data the cache will buffer ahead of what has been
5754 sent to the client when retrieving an object from another server.
5758 IFDEF: USE_HTTP_VIOLATIONS
5761 LOC: Config.negativeTtl
5764 Set the Default Time-to-Live (TTL) for failed requests.
5765 Certain types of failures (such as "connection refused" and
5766 "404 Not Found") are able to be negatively-cached for a short time.
5767 Modern web servers should provide Expires: header, however if they
5768 do not this can provide a minimum TTL.
5769 The default is not to cache errors with unknown expiry details.
5771 Note that this is different from negative caching of DNS lookups.
5773 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5774 this feature could make you liable for problems which it
5778 NAME: positive_dns_ttl
5781 LOC: Config.positiveDnsTtl
5784 Upper limit on how long Squid will cache positive DNS responses.
5785 Default is 6 hours (360 minutes). This directive must be set
5786 larger than negative_dns_ttl.
5789 NAME: negative_dns_ttl
5792 LOC: Config.negativeDnsTtl
5795 Time-to-Live (TTL) for negative caching of failed DNS lookups.
5796 This also sets the lower cache limit on positive lookups.
5797 Minimum value is 1 second, and it is not recommendable to go
5798 much below 10 seconds.
5801 NAME: range_offset_limit
5802 COMMENT: size [acl acl...]
5804 LOC: Config.rangeOffsetLimit
5807 usage: (size) [units] [[!]aclname]
5809 Sets an upper limit on how far (number of bytes) into the file
5810 a Range request may be to cause Squid to prefetch the whole file.
5811 If beyond this limit, Squid forwards the Range request as it is and
5812 the result is NOT cached.
5814 This is to stop a far ahead range request (lets say start at 17MB)
5815 from making Squid fetch the whole object up to that point before
5816 sending anything to the client.
5818 Multiple range_offset_limit lines may be specified, and they will
5819 be searched from top to bottom on each request until a match is found.
5820 The first match found will be used. If no line matches a request, the
5821 default limit of 0 bytes will be used.
5823 'size' is the limit specified as a number of units.
5825 'units' specifies whether to use bytes, KB, MB, etc.
5826 If no units are specified bytes are assumed.
5828 A size of 0 causes Squid to never fetch more than the
5829 client requested. (default)
5831 A size of 'none' causes Squid to always fetch the object from the
5832 beginning so it may cache the result. (2.0 style)
5834 'aclname' is the name of a defined ACL.
5836 NP: Using 'none' as the byte value here will override any quick_abort settings
5837 that may otherwise apply to the range request. The range request will
5838 be fully fetched from start to finish regardless of the client
5839 actions. This affects bandwidth usage.
5842 NAME: minimum_expiry_time
5845 LOC: Config.minimum_expiry_time
5848 The minimum caching time according to (Expires - Date)
5849 headers Squid honors if the object can't be revalidated.
5850 The default is 60 seconds.
5852 In reverse proxy environments it might be desirable to honor
5853 shorter object lifetimes. It is most likely better to make
5854 your server return a meaningful Last-Modified header however.
5856 In ESI environments where page fragments often have short
5857 lifetimes, this will often be best set to 0.
5860 NAME: store_avg_object_size
5864 LOC: Config.Store.avgObjectSize
5866 Average object size, used to estimate number of objects your
5867 cache can hold. The default is 13 KB.
5869 This is used to pre-seed the cache index memory allocation to
5870 reduce expensive reallocate operations while handling clients
5871 traffic. Too-large values may result in memory allocation during
5872 peak traffic, too-small values will result in wasted memory.
5874 Check the cache manager 'info' report metrics for the real
5875 object sizes seen by your Squid before tuning this.
5878 NAME: store_objects_per_bucket
5881 LOC: Config.Store.objectsPerBucket
5883 Target number of objects per bucket in the store hash table.
5884 Lowering this value increases the total number of buckets and
5885 also the storage maintenance rate. The default is 20.
5890 -----------------------------------------------------------------------------
5893 NAME: request_header_max_size
5897 LOC: Config.maxRequestHeaderSize
5899 This specifies the maximum size for HTTP headers in a request.
5900 Request headers are usually relatively small (about 512 bytes).
5901 Placing a limit on the request header size will catch certain
5902 bugs (for example with persistent connections) and possibly
5903 buffer-overflow or denial-of-service attacks.
5906 NAME: reply_header_max_size
5910 LOC: Config.maxReplyHeaderSize
5912 This specifies the maximum size for HTTP headers in a reply.
5913 Reply headers are usually relatively small (about 512 bytes).
5914 Placing a limit on the reply header size will catch certain
5915 bugs (for example with persistent connections) and possibly
5916 buffer-overflow or denial-of-service attacks.
5919 NAME: request_body_max_size
5923 DEFAULT_DOC: No limit.
5924 LOC: Config.maxRequestBodySize
5926 This specifies the maximum size for an HTTP request body.
5927 In other words, the maximum size of a PUT/POST request.
5928 A user who attempts to send a request with a body larger
5929 than this limit receives an "Invalid Request" error message.
5930 If you set this parameter to a zero (the default), there will
5931 be no limit imposed.
5933 See also client_request_buffer_max_size for an alternative
5934 limitation on client uploads which can be configured.
5937 NAME: client_request_buffer_max_size
5941 LOC: Config.maxRequestBufferSize
5943 This specifies the maximum buffer size of a client request.
5944 It prevents squid eating too much memory when somebody uploads
5949 IFDEF: USE_HTTP_VIOLATIONS
5952 DEFAULT_DOC: Obey RFC 2616.
5953 LOC: Config.accessList.brokenPosts
5955 A list of ACL elements which, if matched, causes Squid to send
5956 an extra CRLF pair after the body of a PUT/POST request.
5958 Some HTTP servers has broken implementations of PUT/POST,
5959 and rely on an extra CRLF pair sent by some WWW clients.
5961 Quote from RFC2616 section 4.1 on this matter:
5963 Note: certain buggy HTTP/1.0 client implementations generate an
5964 extra CRLF's after a POST request. To restate what is explicitly
5965 forbidden by the BNF, an HTTP/1.1 client must not preface or follow
5966 a request with an extra CRLF.
5968 This clause only supports fast acl types.
5969 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5972 acl buggy_server url_regex ^http://....
5973 broken_posts allow buggy_server
5976 NAME: adaptation_uses_indirect_client icap_uses_indirect_client
5979 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_ADAPTATION
5981 LOC: Adaptation::Config::use_indirect_client
5983 Controls whether the indirect client IP address (instead of the direct
5984 client IP address) is passed to adaptation services.
5986 See also: follow_x_forwarded_for adaptation_send_client_ip
5990 IFDEF: USE_HTTP_VIOLATIONS
5994 LOC: Config.onoff.via
5996 If set (default), Squid will include a Via header in requests and
5997 replies as required by RFC2616.
6000 NAME: vary_ignore_expire
6003 LOC: Config.onoff.vary_ignore_expire
6006 Many HTTP servers supporting Vary gives such objects
6007 immediate expiry time with no cache-control header
6008 when requested by a HTTP/1.0 client. This option
6009 enables Squid to ignore such expiry times until
6010 HTTP/1.1 is fully implemented.
6012 WARNING: If turned on this may eventually cause some
6013 varying objects not intended for caching to get cached.
6016 NAME: request_entities
6018 LOC: Config.onoff.request_entities
6021 Squid defaults to deny GET and HEAD requests with request entities,
6022 as the meaning of such requests are undefined in the HTTP standard
6023 even if not explicitly forbidden.
6025 Set this directive to on if you have clients which insists
6026 on sending request entities in GET or HEAD requests. But be warned
6027 that there is server software (both proxies and web servers) which
6028 can fail to properly process this kind of request which may make you
6029 vulnerable to cache pollution attacks if enabled.
6032 NAME: request_header_access
6033 IFDEF: USE_HTTP_VIOLATIONS
6034 TYPE: http_header_access
6035 LOC: Config.request_header_access
6037 DEFAULT_DOC: No limits.
6039 Usage: request_header_access header_name allow|deny [!]aclname ...
6041 WARNING: Doing this VIOLATES the HTTP standard. Enabling
6042 this feature could make you liable for problems which it
6045 This option replaces the old 'anonymize_headers' and the
6046 older 'http_anonymizer' option with something that is much
6047 more configurable. A list of ACLs for each header name allows
6048 removal of specific header fields under specific conditions.
6050 This option only applies to outgoing HTTP request headers (i.e.,
6051 headers sent by Squid to the next HTTP hop such as a cache peer
6052 or an origin server). The option has no effect during cache hit
6053 detection. The equivalent adaptation vectoring point in ICAP
6054 terminology is post-cache REQMOD.
6056 The option is applied to individual outgoing request header
6057 fields. For each request header field F, Squid uses the first
6058 qualifying sets of request_header_access rules:
6060 1. Rules with header_name equal to F's name.
6061 2. Rules with header_name 'Other', provided F's name is not
6062 on the hard-coded list of commonly used HTTP header names.
6063 3. Rules with header_name 'All'.
6065 Within that qualifying rule set, rule ACLs are checked as usual.
6066 If ACLs of an "allow" rule match, the header field is allowed to
6067 go through as is. If ACLs of a "deny" rule match, the header is
6068 removed and request_header_replace is then checked to identify
6069 if the removed header has a replacement. If no rules within the
6070 set have matching ACLs, the header field is left as is.
6072 For example, to achieve the same behavior as the old
6073 'http_anonymizer standard' option, you should use:
6075 request_header_access From deny all
6076 request_header_access Referer deny all
6077 request_header_access User-Agent deny all
6079 Or, to reproduce the old 'http_anonymizer paranoid' feature
6082 request_header_access Authorization allow all
6083 request_header_access Proxy-Authorization allow all
6084 request_header_access Cache-Control allow all
6085 request_header_access Content-Length allow all
6086 request_header_access Content-Type allow all
6087 request_header_access Date allow all
6088 request_header_access Host allow all
6089 request_header_access If-Modified-Since allow all
6090 request_header_access Pragma allow all
6091 request_header_access Accept allow all
6092 request_header_access Accept-Charset allow all
6093 request_header_access Accept-Encoding allow all
6094 request_header_access Accept-Language allow all
6095 request_header_access Connection allow all
6096 request_header_access All deny all
6098 HTTP reply headers are controlled with the reply_header_access directive.
6100 By default, all headers are allowed (no anonymizing is performed).
6103 NAME: reply_header_access
6104 IFDEF: USE_HTTP_VIOLATIONS
6105 TYPE: http_header_access
6106 LOC: Config.reply_header_access
6108 DEFAULT_DOC: No limits.
6110 Usage: reply_header_access header_name allow|deny [!]aclname ...
6112 WARNING: Doing this VIOLATES the HTTP standard. Enabling
6113 this feature could make you liable for problems which it
6116 This option only applies to reply headers, i.e., from the
6117 server to the client.
6119 This is the same as request_header_access, but in the other
6120 direction. Please see request_header_access for detailed
6123 For example, to achieve the same behavior as the old
6124 'http_anonymizer standard' option, you should use:
6126 reply_header_access Server deny all
6127 reply_header_access WWW-Authenticate deny all
6128 reply_header_access Link deny all
6130 Or, to reproduce the old 'http_anonymizer paranoid' feature
6133 reply_header_access Allow allow all
6134 reply_header_access WWW-Authenticate allow all
6135 reply_header_access Proxy-Authenticate allow all
6136 reply_header_access Cache-Control allow all
6137 reply_header_access Content-Encoding allow all
6138 reply_header_access Content-Length allow all
6139 reply_header_access Content-Type allow all
6140 reply_header_access Date allow all
6141 reply_header_access Expires allow all
6142 reply_header_access Last-Modified allow all
6143 reply_header_access Location allow all
6144 reply_header_access Pragma allow all
6145 reply_header_access Content-Language allow all
6146 reply_header_access Retry-After allow all
6147 reply_header_access Title allow all
6148 reply_header_access Content-Disposition allow all
6149 reply_header_access Connection allow all
6150 reply_header_access All deny all
6152 HTTP request headers are controlled with the request_header_access directive.
6154 By default, all headers are allowed (no anonymizing is
6158 NAME: request_header_replace header_replace
6159 IFDEF: USE_HTTP_VIOLATIONS
6160 TYPE: http_header_replace
6161 LOC: Config.request_header_access
6164 Usage: request_header_replace header_name message
6165 Example: request_header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
6167 This option allows you to change the contents of headers
6168 denied with request_header_access above, by replacing them
6169 with some fixed string.
6171 This only applies to request headers, not reply headers.
6173 By default, headers are removed if denied.
6176 NAME: reply_header_replace
6177 IFDEF: USE_HTTP_VIOLATIONS
6178 TYPE: http_header_replace
6179 LOC: Config.reply_header_access
6182 Usage: reply_header_replace header_name message
6183 Example: reply_header_replace Server Foo/1.0
6185 This option allows you to change the contents of headers
6186 denied with reply_header_access above, by replacing them
6187 with some fixed string.
6189 This only applies to reply headers, not request headers.
6191 By default, headers are removed if denied.
6194 NAME: request_header_add
6195 TYPE: HeaderWithAclList
6196 LOC: Config.request_header_add
6199 Usage: request_header_add field-name field-value [ acl ... ]
6200 Example: request_header_add X-Client-CA "CA=%ssl::>cert_issuer" all
6202 This option adds header fields to outgoing HTTP requests (i.e.,
6203 request headers sent by Squid to the next HTTP hop such as a
6204 cache peer or an origin server). The option has no effect during
6205 cache hit detection. The equivalent adaptation vectoring point
6206 in ICAP terminology is post-cache REQMOD.
6208 Field-name is a token specifying an HTTP header name. If a
6209 standard HTTP header name is used, Squid does not check whether
6210 the new header conflicts with any existing headers or violates
6211 HTTP rules. If the request to be modified already contains a
6212 field with the same name, the old field is preserved but the
6213 header field values are not merged.
6215 Field-value is either a token or a quoted string. If quoted
6216 string format is used, then the surrounding quotes are removed
6217 while escape sequences and %macros are processed.
6219 One or more Squid ACLs may be specified to restrict header
6220 injection to matching requests. As always in squid.conf, all
6221 ACLs in the ACL list must be satisfied for the insertion to
6222 happen. The request_header_add supports fast ACLs only.
6224 See also: reply_header_add.
6227 NAME: reply_header_add
6228 TYPE: HeaderWithAclList
6229 LOC: Config.reply_header_add
6232 Usage: reply_header_add field-name field-value [ acl ... ]
6233 Example: reply_header_add X-Client-CA "CA=%ssl::>cert_issuer" all
6235 This option adds header fields to outgoing HTTP responses (i.e., response
6236 headers delivered by Squid to the client). This option has no effect on
6237 cache hit detection. The equivalent adaptation vectoring point in
6238 ICAP terminology is post-cache RESPMOD. This option does not apply to
6239 successful CONNECT replies.
6241 Field-name is a token specifying an HTTP header name. If a
6242 standard HTTP header name is used, Squid does not check whether
6243 the new header conflicts with any existing headers or violates
6244 HTTP rules. If the response to be modified already contains a
6245 field with the same name, the old field is preserved but the
6246 header field values are not merged.
6248 Field-value is either a token or a quoted string. If quoted
6249 string format is used, then the surrounding quotes are removed
6250 while escape sequences and %macros are processed.
6252 One or more Squid ACLs may be specified to restrict header
6253 injection to matching responses. As always in squid.conf, all
6254 ACLs in the ACL list must be satisfied for the insertion to
6255 happen. The reply_header_add option supports fast ACLs only.
6257 See also: request_header_add.
6265 This option used to log custom information about the master
6266 transaction. For example, an admin may configure Squid to log
6267 which "user group" the transaction belongs to, where "user group"
6268 will be determined based on a set of ACLs and not [just]
6269 authentication information.
6270 Values of key/value pairs can be logged using %{key}note macros:
6272 note key value acl ...
6273 logformat myFormat ... %{key}note ...
6276 NAME: relaxed_header_parser
6277 COMMENT: on|off|warn
6279 LOC: Config.onoff.relaxed_header_parser
6282 In the default "on" setting Squid accepts certain forms
6283 of non-compliant HTTP messages where it is unambiguous
6284 what the sending application intended even if the message
6285 is not correctly formatted. The messages is then normalized
6286 to the correct form when forwarded by Squid.
6288 If set to "warn" then a warning will be emitted in cache.log
6289 each time such HTTP error is encountered.
6291 If set to "off" then such HTTP errors will cause the request
6292 or response to be rejected.
6295 NAME: collapsed_forwarding
6298 LOC: Config.onoff.collapsed_forwarding
6301 This option controls whether Squid is allowed to merge multiple
6302 potentially cachable requests for the same URI before Squid knows
6303 whether the response is going to be cachable.
6305 When enabled, instead of forwarding each concurrent request for
6306 the same URL, Squid just sends the first of them. The other, so
6307 called "collapsed" requests, wait for the response to the first
6308 request and, if it happens to be cachable, use that response.
6309 Here, "concurrent requests" means "received after the first
6310 request headers were parsed and before the corresponding response
6311 headers were parsed".
6313 This feature is disabled by default: enabling collapsed
6314 forwarding needlessly delays forwarding requests that look
6315 cachable (when they are collapsed) but then need to be forwarded
6316 individually anyway because they end up being for uncachable
6317 content. However, in some cases, such as acceleration of highly
6318 cachable content with periodic or grouped expiration times, the
6319 gains from collapsing [large volumes of simultaneous refresh
6320 requests] outweigh losses from such delays.
6322 Squid collapses two kinds of requests: regular client requests
6323 received on one of the listening ports and internal "cache
6324 revalidation" requests which are triggered by those regular
6325 requests hitting a stale cached object. Revalidation collapsing
6326 is currently disabled for Squid instances containing SMP-aware
6327 disk or memory caches and for Vary-controlled cached objects.
6330 NAME: collapsed_forwarding_shared_entries_limit
6331 COMMENT: (number of entries)
6333 LOC: Config.collapsed_forwarding_shared_entries_limit
6336 This limits the size of a table used for sharing information
6337 about collapsible entries among SMP workers. Limiting sharing
6338 too much results in cache content duplication and missed
6339 collapsing opportunities. Using excessively large values
6340 wastes shared memory.
6342 The limit should be significantly larger then the number of
6343 concurrent collapsible entries one wants to share. For a cache
6344 that handles less than 5000 concurrent requests, the default
6345 setting of 16384 should be plenty.
6347 If the limit is set to zero, it disables sharing of collapsed
6348 forwarding between SMP workers.
6353 -----------------------------------------------------------------------------
6356 NAME: forward_timeout
6359 LOC: Config.Timeout.forward
6362 This parameter specifies how long Squid should at most attempt in
6363 finding a forwarding path for the request before giving up.
6366 NAME: connect_timeout
6369 LOC: Config.Timeout.connect
6372 This parameter specifies how long to wait for the TCP connect to
6373 the requested server or peer to complete before Squid should
6374 attempt to find another path where to forward the request.
6377 NAME: peer_connect_timeout
6380 LOC: Config.Timeout.peer_connect
6383 This parameter specifies how long to wait for a pending TCP
6384 connection to a peer cache. The default is 30 seconds. You
6385 may also set different timeout values for individual neighbors
6386 with the 'connect-timeout' option on a 'cache_peer' line.
6392 LOC: Config.Timeout.read
6395 Applied on peer server connections.
6397 After each successful read(), the timeout will be extended by this
6398 amount. If no data is read again after this amount of time,
6399 the request is aborted and logged with ERR_READ_TIMEOUT.
6401 The default is 15 minutes.
6407 LOC: Config.Timeout.write
6410 This timeout is tracked for all connections that have data
6411 available for writing and are waiting for the socket to become
6412 ready. After each successful write, the timeout is extended by
6413 the configured amount. If Squid has data to write but the
6414 connection is not ready for the configured duration, the
6415 transaction associated with the connection is terminated. The
6416 default is 15 minutes.
6419 NAME: request_timeout
6421 LOC: Config.Timeout.request
6424 How long to wait for complete HTTP request headers after initial
6425 connection establishment.
6428 NAME: request_start_timeout
6430 LOC: Config.Timeout.request_start_timeout
6433 How long to wait for the first request byte after initial
6434 connection establishment.
6437 NAME: client_idle_pconn_timeout persistent_request_timeout
6439 LOC: Config.Timeout.clientIdlePconn
6442 How long to wait for the next HTTP request on a persistent
6443 client connection after the previous request completes.
6446 NAME: ftp_client_idle_timeout
6448 LOC: Config.Timeout.ftpClientIdle
6451 How long to wait for an FTP request on a connection to Squid ftp_port.
6452 Many FTP clients do not deal with idle connection closures well,
6453 necessitating a longer default timeout than client_idle_pconn_timeout
6454 used for incoming HTTP requests.
6457 NAME: client_lifetime
6460 LOC: Config.Timeout.lifetime
6463 The maximum amount of time a client (browser) is allowed to
6464 remain connected to the cache process. This protects the Cache
6465 from having a lot of sockets (and hence file descriptors) tied up
6466 in a CLOSE_WAIT state from remote clients that go away without
6467 properly shutting down (either because of a network failure or
6468 because of a poor client implementation). The default is one
6471 NOTE: The default value is intended to be much larger than any
6472 client would ever need to be connected to your cache. You
6473 should probably change client_lifetime only as a last resort.
6474 If you seem to have many client connections tying up
6475 filedescriptors, we recommend first tuning the read_timeout,
6476 request_timeout, persistent_request_timeout and quick_abort values.
6479 NAME: pconn_lifetime
6482 LOC: Config.Timeout.pconnLifetime
6485 Desired maximum lifetime of a persistent connection.
6486 When set, Squid will close a now-idle persistent connection that
6487 exceeded configured lifetime instead of moving the connection into
6488 the idle connection pool (or equivalent). No effect on ongoing/active
6489 transactions. Connection lifetime is the time period from the
6490 connection acceptance or opening time until "now".
6492 This limit is useful in environments with long-lived connections
6493 where Squid configuration or environmental factors change during a
6494 single connection lifetime. If unrestricted, some connections may
6495 last for hours and even days, ignoring those changes that should
6496 have affected their behavior or their existence.
6498 Currently, a new lifetime value supplied via Squid reconfiguration
6499 has no effect on already idle connections unless they become busy.
6501 When set to '0' this limit is not used.
6504 NAME: half_closed_clients
6506 LOC: Config.onoff.half_closed_clients
6509 Some clients may shutdown the sending side of their TCP
6510 connections, while leaving their receiving sides open. Sometimes,
6511 Squid can not tell the difference between a half-closed and a
6512 fully-closed TCP connection.
6514 By default, Squid will immediately close client connections when
6515 read(2) returns "no more data to read."
6517 Change this option to 'on' and Squid will keep open connections
6518 until a read(2) or write(2) on the socket returns an error.
6519 This may show some benefits for reverse proxies. But if not
6520 it is recommended to leave OFF.
6523 NAME: server_idle_pconn_timeout pconn_timeout
6525 LOC: Config.Timeout.serverIdlePconn
6528 Timeout for idle persistent connections to servers and other
6535 LOC: Ident::TheConfig.timeout
6538 Maximum time to wait for IDENT lookups to complete.
6540 If this is too high, and you enabled IDENT lookups from untrusted
6541 users, you might be susceptible to denial-of-service by having
6542 many ident requests going at once.
6545 NAME: shutdown_lifetime
6548 LOC: Config.shutdownLifetime
6551 When SIGTERM or SIGHUP is received, the cache is put into
6552 "shutdown pending" mode until all active sockets are closed.
6553 This value is the lifetime to set for all open descriptors
6554 during shutdown mode. Any active clients after this many
6555 seconds will receive a 'timeout' message.
6559 ADMINISTRATIVE PARAMETERS
6560 -----------------------------------------------------------------------------
6566 LOC: Config.adminEmail
6568 Email-address of local cache manager who will receive
6569 mail if the cache dies. The default is "webmaster".
6575 LOC: Config.EmailFrom
6577 From: email-address for mail sent when the cache dies.
6578 The default is to use 'squid@unique_hostname'.
6580 See also: unique_hostname directive.
6586 LOC: Config.EmailProgram
6588 Email program used to send mail if the cache dies.
6589 The default is "mail". The specified program must comply
6590 with the standard Unix mail syntax:
6591 mail-program recipient < mailfile
6593 Optional command line options can be specified.
6596 NAME: cache_effective_user
6598 DEFAULT: @DEFAULT_CACHE_EFFECTIVE_USER@
6599 LOC: Config.effectiveUser
6601 If you start Squid as root, it will change its effective/real
6602 UID/GID to the user specified below. The default is to change
6603 to UID of @DEFAULT_CACHE_EFFECTIVE_USER@.
6604 see also; cache_effective_group
6607 NAME: cache_effective_group
6610 DEFAULT_DOC: Use system group memberships of the cache_effective_user account
6611 LOC: Config.effectiveGroup
6613 Squid sets the GID to the effective user's default group ID
6614 (taken from the password file) and supplementary group list
6615 from the groups membership.
6617 If you want Squid to run with a specific GID regardless of
6618 the group memberships of the effective user then set this
6619 to the group (or GID) you want Squid to run as. When set
6620 all other group privileges of the effective user are ignored
6621 and only this GID is effective. If Squid is not started as
6622 root the user starting Squid MUST be member of the specified
6625 This option is not recommended by the Squid Team.
6626 Our preference is for administrators to configure a secure
6627 user account for squid with UID/GID matching system policies.
6630 NAME: httpd_suppress_version_string
6634 LOC: Config.onoff.httpd_suppress_version_string
6636 Suppress Squid version string info in HTTP headers and HTML error pages.
6639 NAME: visible_hostname
6641 LOC: Config.visibleHostname
6643 DEFAULT_DOC: Automatically detect the system host name
6645 If you want to present a special hostname in error messages, etc,
6646 define this. Otherwise, the return value of gethostname()
6647 will be used. If you have multiple caches in a cluster and
6648 get errors about IP-forwarding you must set them to have individual
6649 names with this setting.
6652 NAME: unique_hostname
6654 LOC: Config.uniqueHostname
6656 DEFAULT_DOC: Copy the value from visible_hostname
6658 If you want to have multiple machines with the same
6659 'visible_hostname' you must give each machine a different
6660 'unique_hostname' so forwarding loops can be detected.
6663 NAME: hostname_aliases
6665 LOC: Config.hostnameAliases
6668 A list of other DNS names your cache has.
6676 Minimum umask which should be enforced while the proxy
6677 is running, in addition to the umask set at startup.
6679 For a traditional octal representation of umasks, start
6684 OPTIONS FOR THE CACHE REGISTRATION SERVICE
6685 -----------------------------------------------------------------------------
6687 This section contains parameters for the (optional) cache
6688 announcement service. This service is provided to help
6689 cache administrators locate one another in order to join or
6690 create cache hierarchies.
6692 An 'announcement' message is sent (via UDP) to the registration
6693 service by Squid. By default, the announcement message is NOT
6694 SENT unless you enable it with 'announce_period' below.
6696 The announcement message includes your hostname, plus the
6697 following information from this configuration file:
6703 All current information is processed regularly and made
6704 available on the Web at http://www.ircache.net/Cache/Tracker/.
6707 NAME: announce_period
6709 LOC: Config.Announce.period
6711 DEFAULT_DOC: Announcement messages disabled.
6713 This is how frequently to send cache announcements.
6715 To enable announcing your cache, just set an announce period.
6718 announce_period 1 day
6723 DEFAULT: tracker.ircache.net
6724 LOC: Config.Announce.host
6726 Set the hostname where announce registration messages will be sent.
6728 See also announce_port and announce_file
6734 LOC: Config.Announce.file
6736 The contents of this file will be included in the announce
6737 registration messages.
6743 LOC: Config.Announce.port
6745 Set the port where announce registration messages will be sent.
6747 See also announce_host and announce_file
6751 HTTPD-ACCELERATOR OPTIONS
6752 -----------------------------------------------------------------------------
6755 NAME: httpd_accel_surrogate_id
6758 DEFAULT_DOC: visible_hostname is used if no specific ID is set.
6759 LOC: Config.Accel.surrogate_id
6761 Surrogates (http://www.esi.org/architecture_spec_1.0.html)
6762 need an identification token to allow control targeting. Because
6763 a farm of surrogates may all perform the same tasks, they may share
6764 an identification token.
6767 NAME: http_accel_surrogate_remote
6771 LOC: Config.onoff.surrogate_is_remote
6773 Remote surrogates (such as those in a CDN) honour the header
6774 "Surrogate-Control: no-store-remote".
6776 Set this to on to have squid behave as a remote surrogate.
6780 IFDEF: USE_SQUID_ESI
6781 COMMENT: libxml2|expat|custom
6783 LOC: ESIParser::Type
6786 ESI markup is not strictly XML compatible. The custom ESI parser
6787 will give higher performance, but cannot handle non ASCII character
6792 DELAY POOL PARAMETERS
6793 -----------------------------------------------------------------------------
6797 TYPE: delay_pool_count
6799 IFDEF: USE_DELAY_POOLS
6802 This represents the number of delay pools to be used. For example,
6803 if you have one class 2 delay pool and one class 3 delays pool, you
6804 have a total of 2 delay pools.
6806 See also delay_parameters, delay_class, delay_access for pool
6807 configuration details.
6811 TYPE: delay_pool_class
6813 IFDEF: USE_DELAY_POOLS
6816 This defines the class of each delay pool. There must be exactly one
6817 delay_class line for each delay pool. For example, to define two
6818 delay pools, one of class 2 and one of class 3, the settings above
6822 delay_pools 4 # 4 delay pools
6823 delay_class 1 2 # pool 1 is a class 2 pool
6824 delay_class 2 3 # pool 2 is a class 3 pool
6825 delay_class 3 4 # pool 3 is a class 4 pool
6826 delay_class 4 5 # pool 4 is a class 5 pool
6828 The delay pool classes are:
6830 class 1 Everything is limited by a single aggregate
6833 class 2 Everything is limited by a single aggregate
6834 bucket as well as an "individual" bucket chosen
6835 from bits 25 through 32 of the IPv4 address.
6837 class 3 Everything is limited by a single aggregate
6838 bucket as well as a "network" bucket chosen
6839 from bits 17 through 24 of the IP address and a
6840 "individual" bucket chosen from bits 17 through
6841 32 of the IPv4 address.
6843 class 4 Everything in a class 3 delay pool, with an
6844 additional limit on a per user basis. This
6845 only takes effect if the username is established
6846 in advance - by forcing authentication in your
6849 class 5 Requests are grouped according their tag (see
6850 external_acl's tag= reply).
6853 Each pool also requires a delay_parameters directive to configure the pool size
6854 and speed limits used whenever the pool is applied to a request. Along with
6855 a set of delay_access directives to determine when it is used.
6857 NOTE: If an IP address is a.b.c.d
6858 -> bits 25 through 32 are "d"
6859 -> bits 17 through 24 are "c"
6860 -> bits 17 through 32 are "c * 256 + d"
6862 NOTE-2: Due to the use of bitmasks in class 2,3,4 pools they only apply to
6863 IPv4 traffic. Class 1 and 5 pools may be used with IPv6 traffic.
6865 This clause only supports fast acl types.
6866 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6868 See also delay_parameters and delay_access.
6872 TYPE: delay_pool_access
6874 DEFAULT_DOC: Deny using the pool, unless allow rules exist in squid.conf for the pool.
6875 IFDEF: USE_DELAY_POOLS
6878 This is used to determine which delay pool a request falls into.
6880 delay_access is sorted per pool and the matching starts with pool 1,
6881 then pool 2, ..., and finally pool N. The first delay pool where the
6882 request is allowed is selected for the request. If it does not allow
6883 the request to any pool then the request is not delayed (default).
6885 For example, if you want some_big_clients in delay
6886 pool 1 and lotsa_little_clients in delay pool 2:
6888 delay_access 1 allow some_big_clients
6889 delay_access 1 deny all
6890 delay_access 2 allow lotsa_little_clients
6891 delay_access 2 deny all
6892 delay_access 3 allow authenticated_clients
6894 See also delay_parameters and delay_class.
6898 NAME: delay_parameters
6899 TYPE: delay_pool_rates
6901 IFDEF: USE_DELAY_POOLS
6904 This defines the parameters for a delay pool. Each delay pool has
6905 a number of "buckets" associated with it, as explained in the
6906 description of delay_class.
6908 For a class 1 delay pool, the syntax is:
6910 delay_parameters pool aggregate
6912 For a class 2 delay pool:
6914 delay_parameters pool aggregate individual
6916 For a class 3 delay pool:
6918 delay_parameters pool aggregate network individual
6920 For a class 4 delay pool:
6922 delay_parameters pool aggregate network individual user
6924 For a class 5 delay pool:
6926 delay_parameters pool tagrate
6928 The option variables are:
6930 pool a pool number - ie, a number between 1 and the
6931 number specified in delay_pools as used in
6934 aggregate the speed limit parameters for the aggregate bucket
6937 individual the speed limit parameters for the individual
6938 buckets (class 2, 3).
6940 network the speed limit parameters for the network buckets
6943 user the speed limit parameters for the user buckets
6946 tagrate the speed limit parameters for the tag buckets
6949 A pair of delay parameters is written restore/maximum, where restore is
6950 the number of bytes (not bits - modem and network speeds are usually
6951 quoted in bits) per second placed into the bucket, and maximum is the
6952 maximum number of bytes which can be in the bucket at any time.
6954 There must be one delay_parameters line for each delay pool.
6957 For example, if delay pool number 1 is a class 2 delay pool as in the
6958 above example, and is being used to strictly limit each host to 64Kbit/sec
6959 (plus overheads), with no overall limit, the line is:
6961 delay_parameters 1 none 8000/8000
6963 Note that 8 x 8K Byte/sec -> 64K bit/sec.
6965 Note that the word 'none' is used to represent no limit.
6968 And, if delay pool number 2 is a class 3 delay pool as in the above
6969 example, and you want to limit it to a total of 256Kbit/sec (strict limit)
6970 with each 8-bit network permitted 64Kbit/sec (strict limit) and each
6971 individual host permitted 4800bit/sec with a bucket maximum size of 64Kbits
6972 to permit a decent web page to be downloaded at a decent speed
6973 (if the network is not being limited due to overuse) but slow down
6974 large downloads more significantly:
6976 delay_parameters 2 32000/32000 8000/8000 600/8000
6978 Note that 8 x 32K Byte/sec -> 256K bit/sec.
6979 8 x 8K Byte/sec -> 64K bit/sec.
6980 8 x 600 Byte/sec -> 4800 bit/sec.
6983 Finally, for a class 4 delay pool as in the example - each user will
6984 be limited to 128Kbits/sec no matter how many workstations they are logged into.:
6986 delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000
6989 See also delay_class and delay_access.
6993 NAME: delay_initial_bucket_level
6994 COMMENT: (percent, 0-100)
6997 IFDEF: USE_DELAY_POOLS
6998 LOC: Config.Delay.initial
7000 The initial bucket percentage is used to determine how much is put
7001 in each bucket when squid starts, is reconfigured, or first notices
7002 a host accessing it (in class 2 and class 3, individual hosts and
7003 networks only have buckets associated with them once they have been
7008 CLIENT DELAY POOL PARAMETERS
7009 -----------------------------------------------------------------------------
7012 NAME: client_delay_pools
7013 TYPE: client_delay_pool_count
7015 IFDEF: USE_DELAY_POOLS
7016 LOC: Config.ClientDelay
7018 This option specifies the number of client delay pools used. It must
7019 preceed other client_delay_* options.
7022 client_delay_pools 2
7024 See also client_delay_parameters and client_delay_access.
7027 NAME: client_delay_initial_bucket_level
7028 COMMENT: (percent, 0-no_limit)
7031 IFDEF: USE_DELAY_POOLS
7032 LOC: Config.ClientDelay.initial
7034 This option determines the initial bucket size as a percentage of
7035 max_bucket_size from client_delay_parameters. Buckets are created
7036 at the time of the "first" connection from the matching IP. Idle
7037 buckets are periodically deleted up.
7039 You can specify more than 100 percent but note that such "oversized"
7040 buckets are not refilled until their size goes down to max_bucket_size
7041 from client_delay_parameters.
7044 client_delay_initial_bucket_level 50
7047 NAME: client_delay_parameters
7048 TYPE: client_delay_pool_rates
7050 IFDEF: USE_DELAY_POOLS
7051 LOC: Config.ClientDelay
7054 This option configures client-side bandwidth limits using the
7057 client_delay_parameters pool speed_limit max_bucket_size
7059 pool is an integer ID used for client_delay_access matching.
7061 speed_limit is bytes added to the bucket per second.
7063 max_bucket_size is the maximum size of a bucket, enforced after any
7064 speed_limit additions.
7066 Please see the delay_parameters option for more information and
7070 client_delay_parameters 1 1024 2048
7071 client_delay_parameters 2 51200 16384
7073 See also client_delay_access.
7077 NAME: client_delay_access
7078 TYPE: client_delay_pool_access
7080 DEFAULT_DOC: Deny use of the pool, unless allow rules exist in squid.conf for the pool.
7081 IFDEF: USE_DELAY_POOLS
7082 LOC: Config.ClientDelay
7084 This option determines the client-side delay pool for the
7087 client_delay_access pool_ID allow|deny acl_name
7089 All client_delay_access options are checked in their pool ID
7090 order, starting with pool 1. The first checked pool with allowed
7091 request is selected for the request. If no ACL matches or there
7092 are no client_delay_access options, the request bandwidth is not
7095 The ACL-selected pool is then used to find the
7096 client_delay_parameters for the request. Client-side pools are
7097 not used to aggregate clients. Clients are always aggregated
7098 based on their source IP addresses (one bucket per source IP).
7100 This clause only supports fast acl types.
7101 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7102 Additionally, only the client TCP connection details are available.
7103 ACLs testing HTTP properties will not work.
7105 Please see delay_access for more examples.
7108 client_delay_access 1 allow low_rate_network
7109 client_delay_access 2 allow vips_network
7112 See also client_delay_parameters and client_delay_pools.
7116 WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS
7117 -----------------------------------------------------------------------------
7122 LOC: Config.Wccp.router
7124 DEFAULT_DOC: WCCP disabled.
7127 Use this option to define your WCCP ``home'' router for
7130 wccp_router supports a single WCCP(v1) router
7132 wccp2_router supports multiple WCCPv2 routers
7134 only one of the two may be used at the same time and defines
7135 which version of WCCP to use.
7139 TYPE: IpAddress_list
7140 LOC: Config.Wccp2.router
7142 DEFAULT_DOC: WCCPv2 disabled.
7145 Use this option to define your WCCP ``home'' router for
7148 wccp_router supports a single WCCP(v1) router
7150 wccp2_router supports multiple WCCPv2 routers
7152 only one of the two may be used at the same time and defines
7153 which version of WCCP to use.
7158 LOC: Config.Wccp.version
7162 This directive is only relevant if you need to set up WCCP(v1)
7163 to some very old and end-of-life Cisco routers. In all other
7164 setups it must be left unset or at the default setting.
7165 It defines an internal version in the WCCP(v1) protocol,
7166 with version 4 being the officially documented protocol.
7168 According to some users, Cisco IOS 11.2 and earlier only
7169 support WCCP version 3. If you're using that or an earlier
7170 version of IOS, you may need to change this value to 3, otherwise
7171 do not specify this parameter.
7174 NAME: wccp2_rebuild_wait
7176 LOC: Config.Wccp2.rebuildwait
7180 If this is enabled Squid will wait for the cache dir rebuild to finish
7181 before sending the first wccp2 HereIAm packet
7184 NAME: wccp2_forwarding_method
7186 LOC: Config.Wccp2.forwarding_method
7190 WCCP2 allows the setting of forwarding methods between the
7191 router/switch and the cache. Valid values are as follows:
7193 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
7194 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
7196 Currently (as of IOS 12.4) cisco routers only support GRE.
7197 Cisco switches only support the L2 redirect assignment method.
7200 NAME: wccp2_return_method
7202 LOC: Config.Wccp2.return_method
7206 WCCP2 allows the setting of return methods between the
7207 router/switch and the cache for packets that the cache
7208 decides not to handle. Valid values are as follows:
7210 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
7211 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
7213 Currently (as of IOS 12.4) cisco routers only support GRE.
7214 Cisco switches only support the L2 redirect assignment.
7216 If the "ip wccp redirect exclude in" command has been
7217 enabled on the cache interface, then it is still safe for
7218 the proxy server to use a l2 redirect method even if this
7219 option is set to GRE.
7222 NAME: wccp2_assignment_method
7224 LOC: Config.Wccp2.assignment_method
7228 WCCP2 allows the setting of methods to assign the WCCP hash
7229 Valid values are as follows:
7231 hash - Hash assignment
7232 mask - Mask assignment
7234 As a general rule, cisco routers support the hash assignment method
7235 and cisco switches support the mask assignment method.
7240 LOC: Config.Wccp2.info
7241 DEFAULT_IF_NONE: standard 0
7242 DEFAULT_DOC: Use the 'web-cache' standard service.
7245 WCCP2 allows for multiple traffic services. There are two
7246 types: "standard" and "dynamic". The standard type defines
7247 one service id - http (id 0). The dynamic service ids can be from
7248 51 to 255 inclusive. In order to use a dynamic service id
7249 one must define the type of traffic to be redirected; this is done
7250 using the wccp2_service_info option.
7252 The "standard" type does not require a wccp2_service_info option,
7253 just specifying the service id will suffice.
7255 MD5 service authentication can be enabled by adding
7256 "password=<password>" to the end of this service declaration.
7260 wccp2_service standard 0 # for the 'web-cache' standard service
7261 wccp2_service dynamic 80 # a dynamic service type which will be
7262 # fleshed out with subsequent options.
7263 wccp2_service standard 0 password=foo
7266 NAME: wccp2_service_info
7267 TYPE: wccp2_service_info
7268 LOC: Config.Wccp2.info
7272 Dynamic WCCPv2 services require further information to define the
7273 traffic you wish to have diverted.
7277 wccp2_service_info <id> protocol=<protocol> flags=<flag>,<flag>..
7278 priority=<priority> ports=<port>,<port>..
7280 The relevant WCCPv2 flags:
7281 + src_ip_hash, dst_ip_hash
7282 + source_port_hash, dst_port_hash
7283 + src_ip_alt_hash, dst_ip_alt_hash
7284 + src_port_alt_hash, dst_port_alt_hash
7287 The port list can be one to eight entries.
7291 wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source
7292 priority=240 ports=80
7294 Note: the service id must have been defined by a previous
7295 'wccp2_service dynamic <id>' entry.
7300 LOC: Config.Wccp2.weight
7304 Each cache server gets assigned a set of the destination
7305 hash proportional to their weight.
7310 LOC: Config.Wccp.address
7312 DEFAULT_DOC: Address selected by the operating system.
7315 Use this option if you require WCCPv2 to use a specific
7318 The default behavior is to not bind to any specific address.
7323 LOC: Config.Wccp2.address
7325 DEFAULT_DOC: Address selected by the operating system.
7328 Use this option if you require WCCP to use a specific
7331 The default behavior is to not bind to any specific address.
7335 PERSISTENT CONNECTION HANDLING
7336 -----------------------------------------------------------------------------
7338 Also see "pconn_timeout" in the TIMEOUTS section
7341 NAME: client_persistent_connections
7343 LOC: Config.onoff.client_pconns
7346 Persistent connection support for clients.
7347 Squid uses persistent connections (when allowed). You can use
7348 this option to disable persistent connections with clients.
7351 NAME: server_persistent_connections
7353 LOC: Config.onoff.server_pconns
7356 Persistent connection support for servers.
7357 Squid uses persistent connections (when allowed). You can use
7358 this option to disable persistent connections with servers.
7361 NAME: persistent_connection_after_error
7363 LOC: Config.onoff.error_pconns
7366 With this directive the use of persistent connections after
7367 HTTP errors can be disabled. Useful if you have clients
7368 who fail to handle errors on persistent connections proper.
7371 NAME: detect_broken_pconn
7373 LOC: Config.onoff.detect_broken_server_pconns
7376 Some servers have been found to incorrectly signal the use
7377 of HTTP/1.0 persistent connections even on replies not
7378 compatible, causing significant delays. This server problem
7379 has mostly been seen on redirects.
7381 By enabling this directive Squid attempts to detect such
7382 broken replies and automatically assume the reply is finished
7383 after 10 seconds timeout.
7387 CACHE DIGEST OPTIONS
7388 -----------------------------------------------------------------------------
7391 NAME: digest_generation
7392 IFDEF: USE_CACHE_DIGESTS
7394 LOC: Config.onoff.digest_generation
7397 This controls whether the server will generate a Cache Digest
7398 of its contents. By default, Cache Digest generation is
7399 enabled if Squid is compiled with --enable-cache-digests defined.
7402 NAME: digest_bits_per_entry
7403 IFDEF: USE_CACHE_DIGESTS
7405 LOC: Config.digest.bits_per_entry
7408 This is the number of bits of the server's Cache Digest which
7409 will be associated with the Digest entry for a given HTTP
7410 Method and URL (public key) combination. The default is 5.
7413 NAME: digest_rebuild_period
7414 IFDEF: USE_CACHE_DIGESTS
7417 LOC: Config.digest.rebuild_period
7420 This is the wait time between Cache Digest rebuilds.
7423 NAME: digest_rewrite_period
7425 IFDEF: USE_CACHE_DIGESTS
7427 LOC: Config.digest.rewrite_period
7430 This is the wait time between Cache Digest writes to
7434 NAME: digest_swapout_chunk_size
7437 IFDEF: USE_CACHE_DIGESTS
7438 LOC: Config.digest.swapout_chunk_size
7441 This is the number of bytes of the Cache Digest to write to
7442 disk at a time. It defaults to 4096 bytes (4KB), the Squid
7446 NAME: digest_rebuild_chunk_percentage
7447 COMMENT: (percent, 0-100)
7448 IFDEF: USE_CACHE_DIGESTS
7450 LOC: Config.digest.rebuild_chunk_percentage
7453 This is the percentage of the Cache Digest to be scanned at a
7454 time. By default it is set to 10% of the Cache Digest.
7459 -----------------------------------------------------------------------------
7464 LOC: Config.Port.snmp
7466 DEFAULT_DOC: SNMP disabled.
7469 The port number where Squid listens for SNMP requests. To enable
7470 SNMP support set this to a suitable port number. Port number
7471 3401 is often used for the Squid SNMP agent. By default it's
7472 set to "0" (disabled)
7480 LOC: Config.accessList.snmp
7482 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
7485 Allowing or denying access to the SNMP port.
7487 All access to the agent is denied by default.
7490 snmp_access allow|deny [!]aclname ...
7492 This clause only supports fast acl types.
7493 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7496 snmp_access allow snmppublic localhost
7497 snmp_access deny all
7500 NAME: snmp_incoming_address
7502 LOC: Config.Addrs.snmp_incoming
7504 DEFAULT_DOC: Accept SNMP packets from all machine interfaces.
7507 Just like 'udp_incoming_address', but for the SNMP port.
7509 snmp_incoming_address is used for the SNMP socket receiving
7510 messages from SNMP agents.
7512 The default snmp_incoming_address is to listen on all
7513 available network interfaces.
7516 NAME: snmp_outgoing_address
7518 LOC: Config.Addrs.snmp_outgoing
7520 DEFAULT_DOC: Use snmp_incoming_address or an address selected by the operating system.
7523 Just like 'udp_outgoing_address', but for the SNMP port.
7525 snmp_outgoing_address is used for SNMP packets returned to SNMP
7528 If snmp_outgoing_address is not set it will use the same socket
7529 as snmp_incoming_address. Only change this if you want to have
7530 SNMP replies sent using another address than where this Squid
7531 listens for SNMP queries.
7533 NOTE, snmp_incoming_address and snmp_outgoing_address can not have
7534 the same value since they both use the same port.
7539 -----------------------------------------------------------------------------
7542 NAME: icp_port udp_port
7545 DEFAULT_DOC: ICP disabled.
7546 LOC: Config.Port.icp
7548 The port number where Squid sends and receives ICP queries to
7549 and from neighbor caches. The standard UDP port for ICP is 3130.
7552 icp_port @DEFAULT_ICP_PORT@
7559 DEFAULT_DOC: HTCP disabled.
7560 LOC: Config.Port.htcp
7562 The port number where Squid sends and receives HTCP queries to
7563 and from neighbor caches. To turn it on you want to set it to
7570 NAME: log_icp_queries
7574 LOC: Config.onoff.log_udp
7576 If set, ICP queries are logged to access.log. You may wish
7577 do disable this if your ICP load is VERY high to speed things
7578 up or to simplify log analysis.
7581 NAME: udp_incoming_address
7583 LOC:Config.Addrs.udp_incoming
7585 DEFAULT_DOC: Accept packets from all machine interfaces.
7587 udp_incoming_address is used for UDP packets received from other
7590 The default behavior is to not bind to any specific address.
7592 Only change this if you want to have all UDP queries received on
7593 a specific interface/address.
7595 NOTE: udp_incoming_address is used by the ICP, HTCP, and DNS
7596 modules. Altering it will affect all of them in the same manner.
7598 see also; udp_outgoing_address
7600 NOTE, udp_incoming_address and udp_outgoing_address can not
7601 have the same value since they both use the same port.
7604 NAME: udp_outgoing_address
7606 LOC: Config.Addrs.udp_outgoing
7608 DEFAULT_DOC: Use udp_incoming_address or an address selected by the operating system.
7610 udp_outgoing_address is used for UDP packets sent out to other
7613 The default behavior is to not bind to any specific address.
7615 Instead it will use the same socket as udp_incoming_address.
7616 Only change this if you want to have UDP queries sent using another
7617 address than where this Squid listens for UDP queries from other
7620 NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS
7621 modules. Altering it will affect all of them in the same manner.
7623 see also; udp_incoming_address
7625 NOTE, udp_incoming_address and udp_outgoing_address can not
7626 have the same value since they both use the same port.
7633 LOC: Config.onoff.icp_hit_stale
7635 If you want to return ICP_HIT for stale cache objects, set this
7636 option to 'on'. If you have sibling relationships with caches
7637 in other administrative domains, this should be 'off'. If you only
7638 have sibling relationships with caches under your control,
7639 it is probably okay to set this to 'on'.
7640 If set to 'on', your siblings should use the option "allow-miss"
7641 on their cache_peer lines for connecting to you.
7644 NAME: minimum_direct_hops
7647 LOC: Config.minDirectHops
7649 If using the ICMP pinging stuff, do direct fetches for sites
7650 which are no more than this many hops away.
7653 NAME: minimum_direct_rtt
7657 LOC: Config.minDirectRtt
7659 If using the ICMP pinging stuff, do direct fetches for sites
7660 which are no more than this many rtt milliseconds away.
7666 LOC: Config.Netdb.low
7668 The low water mark for the ICMP measurement database.
7670 Note: high watermark controlled by netdb_high directive.
7672 These watermarks are counts, not percents. The defaults are
7673 (low) 900 and (high) 1000. When the high water mark is
7674 reached, database entries will be deleted until the low
7681 LOC: Config.Netdb.high
7683 The high water mark for the ICMP measurement database.
7685 Note: low watermark controlled by netdb_low directive.
7687 These watermarks are counts, not percents. The defaults are
7688 (low) 900 and (high) 1000. When the high water mark is
7689 reached, database entries will be deleted until the low
7693 NAME: netdb_ping_period
7695 LOC: Config.Netdb.period
7698 The minimum period for measuring a site. There will be at
7699 least this much delay between successive pings to the same
7700 network. The default is five minutes.
7707 LOC: Config.onoff.query_icmp
7709 If you want to ask your peers to include ICMP data in their ICP
7710 replies, enable this option.
7712 If your peer has configured Squid (during compilation) with
7713 '--enable-icmp' that peer will send ICMP pings to origin server
7714 sites of the URLs it receives. If you enable this option the
7715 ICP replies from that peer will include the ICMP data (if available).
7716 Then, when choosing a parent cache, Squid will choose the parent with
7717 the minimal RTT to the origin server. When this happens, the
7718 hierarchy field of the access.log will be
7719 "CLOSEST_PARENT_MISS". This option is off by default.
7722 NAME: test_reachability
7726 LOC: Config.onoff.test_reachability
7728 When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
7729 instead of ICP_MISS if the target host is NOT in the ICMP
7730 database, or has a zero RTT.
7733 NAME: icp_query_timeout
7736 DEFAULT_DOC: Dynamic detection.
7738 LOC: Config.Timeout.icp_query
7740 Normally Squid will automatically determine an optimal ICP
7741 query timeout value based on the round-trip-time of recent ICP
7742 queries. If you want to override the value determined by
7743 Squid, set this 'icp_query_timeout' to a non-zero value. This
7744 value is specified in MILLISECONDS, so, to use a 2-second
7745 timeout (the old default), you would write:
7747 icp_query_timeout 2000
7750 NAME: maximum_icp_query_timeout
7754 LOC: Config.Timeout.icp_query_max
7756 Normally the ICP query timeout is determined dynamically. But
7757 sometimes it can lead to very large values (say 5 seconds).
7758 Use this option to put an upper limit on the dynamic timeout
7759 value. Do NOT use this option to always use a fixed (instead
7760 of a dynamic) timeout value. To set a fixed timeout see the
7761 'icp_query_timeout' directive.
7764 NAME: minimum_icp_query_timeout
7768 LOC: Config.Timeout.icp_query_min
7770 Normally the ICP query timeout is determined dynamically. But
7771 sometimes it can lead to very small timeouts, even lower than
7772 the normal latency variance on your link due to traffic.
7773 Use this option to put an lower limit on the dynamic timeout
7774 value. Do NOT use this option to always use a fixed (instead
7775 of a dynamic) timeout value. To set a fixed timeout see the
7776 'icp_query_timeout' directive.
7779 NAME: background_ping_rate
7783 LOC: Config.backgroundPingRate
7785 Controls how often the ICP pings are sent to siblings that
7786 have background-ping set.
7790 MULTICAST ICP OPTIONS
7791 -----------------------------------------------------------------------------
7796 LOC: Config.mcast_group_list
7799 This tag specifies a list of multicast groups which your server
7800 should join to receive multicasted ICP queries.
7802 NOTE! Be very careful what you put here! Be sure you
7803 understand the difference between an ICP _query_ and an ICP
7804 _reply_. This option is to be set only if you want to RECEIVE
7805 multicast queries. Do NOT set this option to SEND multicast
7806 ICP (use cache_peer for that). ICP replies are always sent via
7807 unicast, so this option does not affect whether or not you will
7808 receive replies from multicast group members.
7810 You must be very careful to NOT use a multicast address which
7811 is already in use by another group of caches.
7813 If you are unsure about multicast, please read the Multicast
7814 chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
7816 Usage: mcast_groups 239.128.16.128 224.0.1.20
7818 By default, Squid doesn't listen on any multicast groups.
7821 NAME: mcast_miss_addr
7822 IFDEF: MULTICAST_MISS_STREAM
7824 LOC: Config.mcast_miss.addr
7826 DEFAULT_DOC: disabled.
7828 If you enable this option, every "cache miss" URL will
7829 be sent out on the specified multicast address.
7831 Do not enable this option unless you are are absolutely
7832 certain you understand what you are doing.
7835 NAME: mcast_miss_ttl
7836 IFDEF: MULTICAST_MISS_STREAM
7838 LOC: Config.mcast_miss.ttl
7841 This is the time-to-live value for packets multicasted
7842 when multicasting off cache miss URLs is enabled. By
7843 default this is set to 'site scope', i.e. 16.
7846 NAME: mcast_miss_port
7847 IFDEF: MULTICAST_MISS_STREAM
7849 LOC: Config.mcast_miss.port
7852 This is the port number to be used in conjunction with
7856 NAME: mcast_miss_encode_key
7857 IFDEF: MULTICAST_MISS_STREAM
7859 LOC: Config.mcast_miss.encode_key
7860 DEFAULT: XXXXXXXXXXXXXXXX
7862 The URLs that are sent in the multicast miss stream are
7863 encrypted. This is the encryption key.
7866 NAME: mcast_icp_query_timeout
7870 LOC: Config.Timeout.mcast_icp_query
7872 For multicast peers, Squid regularly sends out ICP "probes" to
7873 count how many other peers are listening on the given multicast
7874 address. This value specifies how long Squid should wait to
7875 count all the replies. The default is 2000 msec, or 2
7880 INTERNAL ICON OPTIONS
7881 -----------------------------------------------------------------------------
7884 NAME: icon_directory
7886 LOC: Config.icons.directory
7887 DEFAULT: @DEFAULT_ICON_DIR@
7889 Where the icons are stored. These are normally kept in
7893 NAME: global_internal_static
7895 LOC: Config.onoff.global_internal_static
7898 This directive controls is Squid should intercept all requests for
7899 /squid-internal-static/ no matter which host the URL is requesting
7900 (default on setting), or if nothing special should be done for
7901 such URLs (off setting). The purpose of this directive is to make
7902 icons etc work better in complex cache hierarchies where it may
7903 not always be possible for all corners in the cache mesh to reach
7904 the server generating a directory listing.
7907 NAME: short_icon_urls
7909 LOC: Config.icons.use_short_names
7912 If this is enabled Squid will use short URLs for icons.
7913 If disabled it will revert to the old behavior of including
7914 it's own name and port in the URL.
7916 If you run a complex cache hierarchy with a mix of Squid and
7917 other proxies you may need to disable this directive.
7922 -----------------------------------------------------------------------------
7925 NAME: error_directory
7927 LOC: Config.errorDirectory
7929 DEFAULT_DOC: Send error pages in the clients preferred language
7931 If you wish to create your own versions of the default
7932 error files to customize them to suit your company copy
7933 the error/template files to another directory and point
7936 WARNING: This option will disable multi-language support
7937 on error pages if used.
7939 The squid developers are interested in making squid available in
7940 a wide variety of languages. If you are making translations for a
7941 language that Squid does not currently provide please consider
7942 contributing your translation back to the project.
7943 http://wiki.squid-cache.org/Translations
7945 The squid developers working on translations are happy to supply drop-in
7946 translated error files in exchange for any new language contributions.
7949 NAME: error_default_language
7950 IFDEF: USE_ERR_LOCALES
7952 LOC: Config.errorDefaultLanguage
7954 DEFAULT_DOC: Generate English language pages.
7956 Set the default language which squid will send error pages in
7957 if no existing translation matches the clients language
7960 If unset (default) generic English will be used.
7962 The squid developers are interested in making squid available in
7963 a wide variety of languages. If you are interested in making
7964 translations for any language see the squid wiki for details.
7965 http://wiki.squid-cache.org/Translations
7968 NAME: error_log_languages
7969 IFDEF: USE_ERR_LOCALES
7971 LOC: Config.errorLogMissingLanguages
7974 Log to cache.log what languages users are attempting to
7975 auto-negotiate for translations.
7977 Successful negotiations are not logged. Only failures
7978 have meaning to indicate that Squid may need an upgrade
7979 of its error page translations.
7982 NAME: err_page_stylesheet
7984 LOC: Config.errorStylesheet
7985 DEFAULT: @DEFAULT_CONFIG_DIR@/errorpage.css
7987 CSS Stylesheet to pattern the display of Squid default error pages.
7989 For information on CSS see http://www.w3.org/Style/CSS/
7994 LOC: Config.errHtmlText
7997 HTML text to include in error messages. Make this a "mailto"
7998 URL to your admin address, or maybe just a link to your
7999 organizations Web page.
8001 To include this in your error messages, you must rewrite
8002 the error template files (found in the "errors" directory).
8003 Wherever you want the 'err_html_text' line to appear,
8004 insert a %L tag in the error template file.
8007 NAME: email_err_data
8010 LOC: Config.onoff.emailErrData
8013 If enabled, information about the occurred error will be
8014 included in the mailto links of the ERR pages (if %W is set)
8015 so that the email body contains the data.
8016 Syntax is <A HREF="mailto:%w%W">%w</A>
8021 LOC: Config.denyInfoList
8024 Usage: deny_info err_page_name acl
8025 or deny_info http://... acl
8026 or deny_info TCP_RESET acl
8028 This can be used to return a ERR_ page for requests which
8029 do not pass the 'http_access' rules. Squid remembers the last
8030 acl it evaluated in http_access, and if a 'deny_info' line exists
8031 for that ACL Squid returns a corresponding error page.
8033 The acl is typically the last acl on the http_access deny line which
8034 denied access. The exceptions to this rule are:
8035 - When Squid needs to request authentication credentials. It's then
8036 the first authentication related acl encountered
8037 - When none of the http_access lines matches. It's then the last
8038 acl processed on the last http_access line.
8039 - When the decision to deny access was made by an adaptation service,
8040 the acl name is the corresponding eCAP or ICAP service_name.
8042 NP: If providing your own custom error pages with error_directory
8043 you may also specify them by your custom file name:
8044 Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
8046 By defaut Squid will send "403 Forbidden". A different 4xx or 5xx
8047 may be specified by prefixing the file name with the code and a colon.
8048 e.g. 404:ERR_CUSTOM_ACCESS_DENIED
8050 Alternatively you can tell Squid to reset the TCP connection
8051 by specifying TCP_RESET.
8053 Or you can specify an error URL or URL pattern. The browsers will
8054 get redirected to the specified URL after formatting tags have
8055 been replaced. Redirect will be done with 302 or 307 according to
8056 HTTP/1.1 specs. A different 3xx code may be specified by prefixing
8057 the URL. e.g. 303:http://example.com/
8060 %a - username (if available. Password NOT included)
8063 %E - Error description
8065 %H - Request domain name
8066 %i - Client IP Address
8068 %O - Unescaped message result from external ACL helper
8069 %o - Message result from external ACL helper
8070 %p - Request Port number
8071 %P - Request Protocol name
8072 %R - Request URL path
8073 %T - Timestamp in RFC 1123 format
8074 %U - Full canonical URL from client
8075 (HTTPS URLs terminate with *)
8076 %u - Full canonical URL from client
8077 %w - Admin email from squid.conf
8079 %% - Literal percent (%) code
8084 OPTIONS INFLUENCING REQUEST FORWARDING
8085 -----------------------------------------------------------------------------
8088 NAME: nonhierarchical_direct
8090 LOC: Config.onoff.nonhierarchical_direct
8093 By default, Squid will send any non-hierarchical requests
8094 (not cacheable request type) direct to origin servers.
8096 When this is set to "off", Squid will prefer to send these
8097 requests to parents.
8099 Note that in most configurations, by turning this off you will only
8100 add latency to these request without any improvement in global hit
8103 This option only sets a preference. If the parent is unavailable a
8104 direct connection to the origin server may still be attempted. To
8105 completely prevent direct connections use never_direct.
8110 LOC: Config.onoff.prefer_direct
8113 Normally Squid tries to use parents for most requests. If you for some
8114 reason like it to first try going direct and only use a parent if
8115 going direct fails set this to on.
8117 By combining nonhierarchical_direct off and prefer_direct on you
8118 can set up Squid to use a parent as a backup path if going direct
8121 Note: If you want Squid to use parents for all requests see
8122 the never_direct directive. prefer_direct only modifies how Squid
8123 acts on cacheable requests.
8126 NAME: cache_miss_revalidate
8130 LOC: Config.onoff.cache_miss_revalidate
8132 RFC 7232 defines a conditional request mechanism to prevent
8133 response objects being unnecessarily transferred over the network.
8134 If that mechanism is used by the client and a cache MISS occurs
8135 it can prevent new cache entries being created.
8137 This option determines whether Squid on cache MISS will pass the
8138 client revalidation request to the server or tries to fetch new
8139 content for caching. It can be useful while the cache is mostly
8140 empty to more quickly have the cache populated by generating
8141 non-conditional GETs.
8143 When set to 'on' (default), Squid will pass all client If-* headers
8144 to the server. This permits server responses without a cacheable
8145 payload to be delivered and on MISS no new cache entry is created.
8147 When set to 'off' and if the request is cacheable, Squid will
8148 remove the clients If-Modified-Since and If-None-Match headers from
8149 the request sent to the server. This requests a 200 status response
8150 from the server to create a new cache entry with.
8155 LOC: Config.accessList.AlwaysDirect
8157 DEFAULT_DOC: Prevent any cache_peer being used for this request.
8159 Usage: always_direct allow|deny [!]aclname ...
8161 Here you can use ACL elements to specify requests which should
8162 ALWAYS be forwarded by Squid to the origin servers without using
8163 any peers. For example, to always directly forward requests for
8164 local servers ignoring any parents or siblings you may have use
8167 acl local-servers dstdomain my.domain.net
8168 always_direct allow local-servers
8170 To always forward FTP requests directly, use
8173 always_direct allow FTP
8175 NOTE: There is a similar, but opposite option named
8176 'never_direct'. You need to be aware that "always_direct deny
8177 foo" is NOT the same thing as "never_direct allow foo". You
8178 may need to use a deny rule to exclude a more-specific case of
8179 some other rule. Example:
8181 acl local-external dstdomain external.foo.net
8182 acl local-servers dstdomain .foo.net
8183 always_direct deny local-external
8184 always_direct allow local-servers
8186 NOTE: If your goal is to make the client forward the request
8187 directly to the origin server bypassing Squid then this needs
8188 to be done in the client configuration. Squid configuration
8189 can only tell Squid how Squid should fetch the object.
8191 NOTE: This directive is not related to caching. The replies
8192 is cached as usual even if you use always_direct. To not cache
8193 the replies see the 'cache' directive.
8195 This clause supports both fast and slow acl types.
8196 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
8201 LOC: Config.accessList.NeverDirect
8203 DEFAULT_DOC: Allow DNS results to be used for this request.
8205 Usage: never_direct allow|deny [!]aclname ...
8207 never_direct is the opposite of always_direct. Please read
8208 the description for always_direct if you have not already.
8210 With 'never_direct' you can use ACL elements to specify
8211 requests which should NEVER be forwarded directly to origin
8212 servers. For example, to force the use of a proxy for all
8213 requests, except those in your local domain use something like:
8215 acl local-servers dstdomain .foo.net
8216 never_direct deny local-servers
8217 never_direct allow all
8219 or if Squid is inside a firewall and there are local intranet
8220 servers inside the firewall use something like:
8222 acl local-intranet dstdomain .foo.net
8223 acl local-external dstdomain external.foo.net
8224 always_direct deny local-external
8225 always_direct allow local-intranet
8226 never_direct allow all
8228 This clause supports both fast and slow acl types.
8229 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
8233 ADVANCED NETWORKING OPTIONS
8234 -----------------------------------------------------------------------------
8237 NAME: incoming_udp_average incoming_icp_average
8240 LOC: Config.comm_incoming.udp.average
8242 Heavy voodoo here. I can't even believe you are reading this.
8243 Are you crazy? Don't even think about adjusting these unless
8244 you understand the algorithms in comm_select.c first!
8247 NAME: incoming_tcp_average incoming_http_average
8250 LOC: Config.comm_incoming.tcp.average
8252 Heavy voodoo here. I can't even believe you are reading this.
8253 Are you crazy? Don't even think about adjusting these unless
8254 you understand the algorithms in comm_select.c first!
8257 NAME: incoming_dns_average
8260 LOC: Config.comm_incoming.dns.average
8262 Heavy voodoo here. I can't even believe you are reading this.
8263 Are you crazy? Don't even think about adjusting these unless
8264 you understand the algorithms in comm_select.c first!
8267 NAME: min_udp_poll_cnt min_icp_poll_cnt
8270 LOC: Config.comm_incoming.udp.min_poll
8272 Heavy voodoo here. I can't even believe you are reading this.
8273 Are you crazy? Don't even think about adjusting these unless
8274 you understand the algorithms in comm_select.c first!
8277 NAME: min_dns_poll_cnt
8280 LOC: Config.comm_incoming.dns.min_poll
8282 Heavy voodoo here. I can't even believe you are reading this.
8283 Are you crazy? Don't even think about adjusting these unless
8284 you understand the algorithms in comm_select.c first!
8287 NAME: min_tcp_poll_cnt min_http_poll_cnt
8290 LOC: Config.comm_incoming.tcp.min_poll
8292 Heavy voodoo here. I can't even believe you are reading this.
8293 Are you crazy? Don't even think about adjusting these unless
8294 you understand the algorithms in comm_select.c first!
8300 LOC: Config.accept_filter
8304 The name of an accept(2) filter to install on Squid's
8305 listen socket(s). This feature is perhaps specific to
8306 FreeBSD and requires support in the kernel.
8308 The 'httpready' filter delays delivering new connections
8309 to Squid until a full HTTP request has been received.
8310 See the accf_http(9) man page for details.
8312 The 'dataready' filter delays delivering new connections
8313 to Squid until there is some data to process.
8314 See the accf_dataready(9) man page for details.
8318 The 'data' filter delays delivering of new connections
8319 to Squid until there is some data to process by TCP_ACCEPT_DEFER.
8320 You may optionally specify a number of seconds to wait by
8321 'data=N' where N is the number of seconds. Defaults to 30
8322 if not specified. See the tcp(7) man page for details.
8325 accept_filter httpready
8330 NAME: client_ip_max_connections
8332 LOC: Config.client_ip_max_connections
8334 DEFAULT_DOC: No limit.
8336 Set an absolute limit on the number of connections a single
8337 client IP can use. Any more than this and Squid will begin to drop
8338 new connections from the client until it closes some links.
8340 Note that this is a global limit. It affects all HTTP, HTCP, Gopher and FTP
8341 connections from the client. For finer control use the ACL access controls.
8343 Requires client_db to be enabled (the default).
8345 WARNING: This may noticably slow down traffic received via external proxies
8346 or NAT devices and cause them to rebound error messages back to their clients.
8349 NAME: tcp_recv_bufsize
8353 DEFAULT_DOC: Use operating system TCP defaults.
8354 LOC: Config.tcpRcvBufsz
8356 Size of receive buffer to set for TCP sockets. Probably just
8357 as easy to change your kernel's default.
8358 Omit from squid.conf to use the default buffer size.
8363 -----------------------------------------------------------------------------
8370 LOC: Adaptation::Icap::TheConfig.onoff
8373 If you want to enable the ICAP module support, set this to on.
8376 NAME: icap_connect_timeout
8379 LOC: Adaptation::Icap::TheConfig.connect_timeout_raw
8382 This parameter specifies how long to wait for the TCP connect to
8383 the requested ICAP server to complete before giving up and either
8384 terminating the HTTP transaction or bypassing the failure.
8386 The default for optional services is peer_connect_timeout.
8387 The default for essential services is connect_timeout.
8388 If this option is explicitly set, its value applies to all services.
8391 NAME: icap_io_timeout
8395 DEFAULT_DOC: Use read_timeout.
8396 LOC: Adaptation::Icap::TheConfig.io_timeout_raw
8399 This parameter specifies how long to wait for an I/O activity on
8400 an established, active ICAP connection before giving up and
8401 either terminating the HTTP transaction or bypassing the
8405 NAME: icap_service_failure_limit
8406 COMMENT: limit [in memory-depth time-units]
8407 TYPE: icap_service_failure_limit
8409 LOC: Adaptation::Icap::TheConfig
8412 The limit specifies the number of failures that Squid tolerates
8413 when establishing a new TCP connection with an ICAP service. If
8414 the number of failures exceeds the limit, the ICAP service is
8415 not used for new ICAP requests until it is time to refresh its
8418 A negative value disables the limit. Without the limit, an ICAP
8419 service will not be considered down due to connectivity failures
8420 between ICAP OPTIONS requests.
8422 Squid forgets ICAP service failures older than the specified
8423 value of memory-depth. The memory fading algorithm
8424 is approximate because Squid does not remember individual
8425 errors but groups them instead, splitting the option
8426 value into ten time slots of equal length.
8428 When memory-depth is 0 and by default this option has no
8429 effect on service failure expiration.
8431 Squid always forgets failures when updating service settings
8432 using an ICAP OPTIONS transaction, regardless of this option
8436 # suspend service usage after 10 failures in 5 seconds:
8437 icap_service_failure_limit 10 in 5 seconds
8440 NAME: icap_service_revival_delay
8443 LOC: Adaptation::Icap::TheConfig.service_revival_delay
8446 The delay specifies the number of seconds to wait after an ICAP
8447 OPTIONS request failure before requesting the options again. The
8448 failed ICAP service is considered "down" until fresh OPTIONS are
8451 The actual delay cannot be smaller than the hardcoded minimum
8452 delay of 30 seconds.
8455 NAME: icap_preview_enable
8459 LOC: Adaptation::Icap::TheConfig.preview_enable
8462 The ICAP Preview feature allows the ICAP server to handle the
8463 HTTP message by looking only at the beginning of the message body
8464 or even without receiving the body at all. In some environments,
8465 previews greatly speedup ICAP processing.
8467 During an ICAP OPTIONS transaction, the server may tell Squid what
8468 HTTP messages should be previewed and how big the preview should be.
8469 Squid will not use Preview if the server did not request one.
8471 To disable ICAP Preview for all ICAP services, regardless of
8472 individual ICAP server OPTIONS responses, set this option to "off".
8474 icap_preview_enable off
8477 NAME: icap_preview_size
8480 LOC: Adaptation::Icap::TheConfig.preview_size
8482 DEFAULT_DOC: No preview sent.
8484 The default size of preview data to be sent to the ICAP server.
8485 This value might be overwritten on a per server basis by OPTIONS requests.
8488 NAME: icap_206_enable
8492 LOC: Adaptation::Icap::TheConfig.allow206_enable
8495 206 (Partial Content) responses is an ICAP extension that allows the
8496 ICAP agents to optionally combine adapted and original HTTP message
8497 content. The decision to combine is postponed until the end of the
8498 ICAP response. Squid supports Partial Content extension by default.
8500 Activation of the Partial Content extension is negotiated with each
8501 ICAP service during OPTIONS exchange. Most ICAP servers should handle
8502 negotation correctly even if they do not support the extension, but
8503 some might fail. To disable Partial Content support for all ICAP
8504 services and to avoid any negotiation, set this option to "off".
8510 NAME: icap_default_options_ttl
8513 LOC: Adaptation::Icap::TheConfig.default_options_ttl
8516 The default TTL value for ICAP OPTIONS responses that don't have
8517 an Options-TTL header.
8520 NAME: icap_persistent_connections
8524 LOC: Adaptation::Icap::TheConfig.reuse_connections
8527 Whether or not Squid should use persistent connections to
8531 NAME: adaptation_send_client_ip icap_send_client_ip
8533 IFDEF: USE_ADAPTATION
8535 LOC: Adaptation::Config::send_client_ip
8538 If enabled, Squid shares HTTP client IP information with adaptation
8539 services. For ICAP, Squid adds the X-Client-IP header to ICAP requests.
8540 For eCAP, Squid sets the libecap::metaClientIp transaction option.
8542 See also: adaptation_uses_indirect_client
8545 NAME: adaptation_send_username icap_send_client_username
8547 IFDEF: USE_ADAPTATION
8549 LOC: Adaptation::Config::send_username
8552 This sends authenticated HTTP client username (if available) to
8553 the adaptation service.
8555 For ICAP, the username value is encoded based on the
8556 icap_client_username_encode option and is sent using the header
8557 specified by the icap_client_username_header option.
8560 NAME: icap_client_username_header
8563 LOC: Adaptation::Icap::TheConfig.client_username_header
8564 DEFAULT: X-Client-Username
8566 ICAP request header name to use for adaptation_send_username.
8569 NAME: icap_client_username_encode
8573 LOC: Adaptation::Icap::TheConfig.client_username_encode
8576 Whether to base64 encode the authenticated client username.
8580 TYPE: icap_service_type
8582 LOC: Adaptation::Icap::TheConfig
8585 Defines a single ICAP service using the following format:
8587 icap_service id vectoring_point uri [option ...]
8590 an opaque identifier or name which is used to direct traffic to
8591 this specific service. Must be unique among all adaptation
8592 services in squid.conf.
8594 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
8595 This specifies at which point of transaction processing the
8596 ICAP service should be activated. *_postcache vectoring points
8597 are not yet supported.
8599 uri: icap://servername:port/servicepath
8600 ICAP server and service location.
8601 icaps://servername:port/servicepath
8602 The "icap:" URI scheme is used for traditional ICAP server and
8603 service location (default port is 1344, connections are not
8604 encrypted). The "icaps:" URI scheme is for Secure ICAP
8605 services that use SSL/TLS-encrypted ICAP connections (by
8606 default, on port 11344).
8608 ICAP does not allow a single service to handle both REQMOD and RESPMOD
8609 transactions. Squid does not enforce that requirement. You can specify
8610 services with the same service_url and different vectoring_points. You
8611 can even specify multiple identical services as long as their
8612 service_names differ.
8614 To activate a service, use the adaptation_access directive. To group
8615 services, use adaptation_service_chain and adaptation_service_set.
8617 Service options are separated by white space. ICAP services support
8618 the following name=value options:
8621 If set to 'on' or '1', the ICAP service is treated as
8622 optional. If the service cannot be reached or malfunctions,
8623 Squid will try to ignore any errors and process the message as
8624 if the service was not enabled. No all ICAP errors can be
8625 bypassed. If set to 0, the ICAP service is treated as
8626 essential and all ICAP errors will result in an error page
8627 returned to the HTTP client.
8629 Bypass is off by default: services are treated as essential.
8632 If set to 'on' or '1', the ICAP service is allowed to
8633 dynamically change the current message adaptation plan by
8634 returning a chain of services to be used next. The services
8635 are specified using the X-Next-Services ICAP response header
8636 value, formatted as a comma-separated list of service names.
8637 Each named service should be configured in squid.conf. Other
8638 services are ignored. An empty X-Next-Services value results
8639 in an empty plan which ends the current adaptation.
8641 Dynamic adaptation plan may cross or cover multiple supported
8642 vectoring points in their natural processing order.
8644 Routing is not allowed by default: the ICAP X-Next-Services
8645 response header is ignored.
8648 Only has effect on split-stack systems. The default on those systems
8649 is to use IPv4-only connections. When set to 'on' this option will
8650 make Squid use IPv6-only connections to contact this ICAP service.
8652 on-overload=block|bypass|wait|force
8653 If the service Max-Connections limit has been reached, do
8654 one of the following for each new ICAP transaction:
8655 * block: send an HTTP error response to the client
8656 * bypass: ignore the "over-connected" ICAP service
8657 * wait: wait (in a FIFO queue) for an ICAP connection slot
8658 * force: proceed, ignoring the Max-Connections limit
8660 In SMP mode with N workers, each worker assumes the service
8661 connection limit is Max-Connections/N, even though not all
8662 workers may use a given service.
8664 The default value is "bypass" if service is bypassable,
8665 otherwise it is set to "wait".
8669 Use the given number as the Max-Connections limit, regardless
8670 of the Max-Connections value given by the service, if any.
8672 connection-encryption=on|off
8673 Determines the ICAP service effect on the connections_encrypted
8676 The default is "on" for Secure ICAP services (i.e., those
8677 with the icaps:// service URIs scheme) and "off" for plain ICAP
8680 Does not affect ICAP connections (e.g., does not turn Secure
8683 ==== ICAPS / TLS OPTIONS ====
8685 These options are used for Secure ICAP (icaps://....) services only.
8687 tls-cert=/path/to/ssl/certificate
8688 A client SSL certificate to use when connecting to
8691 tls-key=/path/to/ssl/key
8692 The private TLS/SSL key corresponding to sslcert above.
8693 If 'tls-key' is not specified 'tls-cert' is assumed to
8694 reference a combined PEM format file containing both the
8695 certificate and the key.
8697 tls-cipher=... The list of valid TLS/SSL ciphers to use when connecting
8698 to this icap server.
8701 The minimum TLS protocol version to permit. To control
8702 SSLv3 use the ssloptions= parameter.
8703 Supported Values: 1.0 (default), 1.1, 1.2
8705 tls-options=... Specify various OpenSSL library options:
8707 NO_SSLv3 Disallow the use of SSLv3
8709 NO_TLSv1 Disallow the use of TLSv1.0
8710 NO_TLSv1_1 Disallow the use of TLSv1.1
8711 NO_TLSv1_2 Disallow the use of TLSv1.2
8714 Always create a new key when using
8715 temporary/ephemeral DH key exchanges
8717 ALL Enable various bug workarounds
8718 suggested as "harmless" by OpenSSL
8719 Be warned that this reduces SSL/TLS
8720 strength to some attacks.
8722 See the OpenSSL SSL_CTX_set_options documentation for a
8723 more complete list. Options relevant only to SSLv2 are
8726 tls-cafile= PEM file containing CA certificates to use when verifying
8727 the icap server certificate.
8728 Use to specify intermediate CA certificate(s) if not sent
8729 by the server. Or the full CA chain for the server when
8730 using the tls-default-ca=off flag.
8731 May be repeated to load multiple files.
8733 tls-capath=... A directory containing additional CA certificates to
8734 use when verifying the icap server certificate.
8735 Requires OpenSSL or LibreSSL.
8737 tls-crlfile=... A certificate revocation list file to use when
8738 verifying the icap server certificate.
8740 tls-flags=... Specify various flags modifying the Squid TLS implementation:
8743 Accept certificates even if they fail to
8746 Don't verify the icap server certificate
8747 matches the server name
8749 tls-default-ca[=off]
8750 Whether to use the system Trusted CAs. Default is ON.
8752 tls-domain= The icap server name as advertised in it's certificate.
8753 Used for verifying the correctness of the received icap
8754 server certificate. If not specified the icap server
8755 hostname extracted from ICAP URI will be used.
8757 Older icap_service format without optional named parameters is
8758 deprecated but supported for backward compatibility.
8761 icap_service svcBlocker reqmod_precache icap://icap1.mydomain.net:1344/reqmod bypass=0
8762 icap_service svcLogger reqmod_precache icaps://icap2.mydomain.net:11344/reqmod routing=on
8766 TYPE: icap_class_type
8771 This deprecated option was documented to define an ICAP service
8772 chain, even though it actually defined a set of similar, redundant
8773 services, and the chains were not supported.
8775 To define a set of redundant services, please use the
8776 adaptation_service_set directive. For service chains, use
8777 adaptation_service_chain.
8781 TYPE: icap_access_type
8786 This option is deprecated. Please use adaptation_access, which
8787 has the same ICAP functionality, but comes with better
8788 documentation, and eCAP support.
8793 -----------------------------------------------------------------------------
8800 LOC: Adaptation::Ecap::TheConfig.onoff
8803 Controls whether eCAP support is enabled.
8807 TYPE: ecap_service_type
8809 LOC: Adaptation::Ecap::TheConfig
8812 Defines a single eCAP service
8814 ecap_service id vectoring_point uri [option ...]
8817 an opaque identifier or name which is used to direct traffic to
8818 this specific service. Must be unique among all adaptation
8819 services in squid.conf.
8821 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
8822 This specifies at which point of transaction processing the
8823 eCAP service should be activated. *_postcache vectoring points
8824 are not yet supported.
8826 uri: ecap://vendor/service_name?custom&cgi=style¶meters=optional
8827 Squid uses the eCAP service URI to match this configuration
8828 line with one of the dynamically loaded services. Each loaded
8829 eCAP service must have a unique URI. Obtain the right URI from
8830 the service provider.
8832 To activate a service, use the adaptation_access directive. To group
8833 services, use adaptation_service_chain and adaptation_service_set.
8835 Service options are separated by white space. eCAP services support
8836 the following name=value options:
8839 If set to 'on' or '1', the eCAP service is treated as optional.
8840 If the service cannot be reached or malfunctions, Squid will try
8841 to ignore any errors and process the message as if the service
8842 was not enabled. No all eCAP errors can be bypassed.
8843 If set to 'off' or '0', the eCAP service is treated as essential
8844 and all eCAP errors will result in an error page returned to the
8847 Bypass is off by default: services are treated as essential.
8850 If set to 'on' or '1', the eCAP service is allowed to
8851 dynamically change the current message adaptation plan by
8852 returning a chain of services to be used next.
8854 Dynamic adaptation plan may cross or cover multiple supported
8855 vectoring points in their natural processing order.
8857 Routing is not allowed by default.
8859 connection-encryption=on|off
8860 Determines the eCAP service effect on the connections_encrypted
8863 Defaults to "on", which does not taint the master transaction
8866 Does not affect eCAP API calls.
8868 Older ecap_service format without optional named parameters is
8869 deprecated but supported for backward compatibility.
8873 ecap_service s1 reqmod_precache ecap://filters.R.us/leakDetector?on_error=block bypass=off
8874 ecap_service s2 respmod_precache ecap://filters.R.us/virusFilter config=/etc/vf.cfg bypass=on
8877 NAME: loadable_modules
8879 IFDEF: USE_LOADABLE_MODULES
8880 LOC: Config.loadable_module_names
8883 Instructs Squid to load the specified dynamic module(s) or activate
8884 preloaded module(s).
8886 loadable_modules @DEFAULT_PREFIX@/lib/MinimalAdapter.so
8890 MESSAGE ADAPTATION OPTIONS
8891 -----------------------------------------------------------------------------
8894 NAME: adaptation_service_set
8895 TYPE: adaptation_service_set_type
8896 IFDEF: USE_ADAPTATION
8901 Configures an ordered set of similar, redundant services. This is
8902 useful when hot standby or backup adaptation servers are available.
8904 adaptation_service_set set_name service_name1 service_name2 ...
8906 The named services are used in the set declaration order. The first
8907 applicable adaptation service from the set is used first. The next
8908 applicable service is tried if and only if the transaction with the
8909 previous service fails and the message waiting to be adapted is still
8912 When adaptation starts, broken services are ignored as if they were
8913 not a part of the set. A broken service is a down optional service.
8915 The services in a set must be attached to the same vectoring point
8916 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
8918 If all services in a set are optional then adaptation failures are
8919 bypassable. If all services in the set are essential, then a
8920 transaction failure with one service may still be retried using
8921 another service from the set, but when all services fail, the master
8922 transaction fails as well.
8924 A set may contain a mix of optional and essential services, but that
8925 is likely to lead to surprising results because broken services become
8926 ignored (see above), making previously bypassable failures fatal.
8927 Technically, it is the bypassability of the last failed service that
8930 See also: adaptation_access adaptation_service_chain
8933 adaptation_service_set svcBlocker urlFilterPrimary urlFilterBackup
8934 adaptation service_set svcLogger loggerLocal loggerRemote
8937 NAME: adaptation_service_chain
8938 TYPE: adaptation_service_chain_type
8939 IFDEF: USE_ADAPTATION
8944 Configures a list of complementary services that will be applied
8945 one-by-one, forming an adaptation chain or pipeline. This is useful
8946 when Squid must perform different adaptations on the same message.
8948 adaptation_service_chain chain_name service_name1 svc_name2 ...
8950 The named services are used in the chain declaration order. The first
8951 applicable adaptation service from the chain is used first. The next
8952 applicable service is applied to the successful adaptation results of
8953 the previous service in the chain.
8955 When adaptation starts, broken services are ignored as if they were
8956 not a part of the chain. A broken service is a down optional service.
8958 Request satisfaction terminates the adaptation chain because Squid
8959 does not currently allow declaration of RESPMOD services at the
8960 "reqmod_precache" vectoring point (see icap_service or ecap_service).
8962 The services in a chain must be attached to the same vectoring point
8963 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
8965 A chain may contain a mix of optional and essential services. If an
8966 essential adaptation fails (or the failure cannot be bypassed for
8967 other reasons), the master transaction fails. Otherwise, the failure
8968 is bypassed as if the failed adaptation service was not in the chain.
8970 See also: adaptation_access adaptation_service_set
8973 adaptation_service_chain svcRequest requestLogger urlFilter leakDetector
8976 NAME: adaptation_access
8977 TYPE: adaptation_access_type
8978 IFDEF: USE_ADAPTATION
8981 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
8983 Sends an HTTP transaction to an ICAP or eCAP adaptation service.
8985 adaptation_access service_name allow|deny [!]aclname...
8986 adaptation_access set_name allow|deny [!]aclname...
8988 At each supported vectoring point, the adaptation_access
8989 statements are processed in the order they appear in this
8990 configuration file. Statements pointing to the following services
8991 are ignored (i.e., skipped without checking their ACL):
8993 - services serving different vectoring points
8994 - "broken-but-bypassable" services
8995 - "up" services configured to ignore such transactions
8996 (e.g., based on the ICAP Transfer-Ignore header).
8998 When a set_name is used, all services in the set are checked
8999 using the same rules, to find the first applicable one. See
9000 adaptation_service_set for details.
9002 If an access list is checked and there is a match, the
9003 processing stops: For an "allow" rule, the corresponding
9004 adaptation service is used for the transaction. For a "deny"
9005 rule, no adaptation service is activated.
9007 It is currently not possible to apply more than one adaptation
9008 service at the same vectoring point to the same HTTP transaction.
9010 See also: icap_service and ecap_service
9013 adaptation_access service_1 allow all
9016 NAME: adaptation_service_iteration_limit
9018 IFDEF: USE_ADAPTATION
9019 LOC: Adaptation::Config::service_iteration_limit
9022 Limits the number of iterations allowed when applying adaptation
9023 services to a message. If your longest adaptation set or chain
9024 may have more than 16 services, increase the limit beyond its
9025 default value of 16. If detecting infinite iteration loops sooner
9026 is critical, make the iteration limit match the actual number
9027 of services in your longest adaptation set or chain.
9029 Infinite adaptation loops are most likely with routing services.
9031 See also: icap_service routing=1
9034 NAME: adaptation_masterx_shared_names
9036 IFDEF: USE_ADAPTATION
9037 LOC: Adaptation::Config::masterx_shared_name
9040 For each master transaction (i.e., the HTTP request and response
9041 sequence, including all related ICAP and eCAP exchanges), Squid
9042 maintains a table of metadata. The table entries are (name, value)
9043 pairs shared among eCAP and ICAP exchanges. The table is destroyed
9044 with the master transaction.
9046 This option specifies the table entry names that Squid must accept
9047 from and forward to the adaptation transactions.
9049 An ICAP REQMOD or RESPMOD transaction may set an entry in the
9050 shared table by returning an ICAP header field with a name
9051 specified in adaptation_masterx_shared_names.
9053 An eCAP REQMOD or RESPMOD transaction may set an entry in the
9054 shared table by implementing the libecap::visitEachOption() API
9055 to provide an option with a name specified in
9056 adaptation_masterx_shared_names.
9058 Squid will store and forward the set entry to subsequent adaptation
9059 transactions within the same master transaction scope.
9061 Only one shared entry name is supported at this time.
9064 # share authentication information among ICAP services
9065 adaptation_masterx_shared_names X-Subscriber-ID
9068 NAME: adaptation_meta
9070 IFDEF: USE_ADAPTATION
9071 LOC: Adaptation::Config::metaHeaders
9074 This option allows Squid administrator to add custom ICAP request
9075 headers or eCAP options to Squid ICAP requests or eCAP transactions.
9076 Use it to pass custom authentication tokens and other
9077 transaction-state related meta information to an ICAP/eCAP service.
9079 The addition of a meta header is ACL-driven:
9080 adaptation_meta name value [!]aclname ...
9082 Processing for a given header name stops after the first ACL list match.
9083 Thus, it is impossible to add two headers with the same name. If no ACL
9084 lists match for a given header name, no such header is added. For
9087 # do not debug transactions except for those that need debugging
9088 adaptation_meta X-Debug 1 needs_debugging
9090 # log all transactions except for those that must remain secret
9091 adaptation_meta X-Log 1 !keep_secret
9093 # mark transactions from users in the "G 1" group
9094 adaptation_meta X-Authenticated-Groups "G 1" authed_as_G1
9096 The "value" parameter may be a regular squid.conf token or a "double
9097 quoted string". Within the quoted string, use backslash (\) to escape
9098 any character, which is currently only useful for escaping backslashes
9099 and double quotes. For example,
9100 "this string has one backslash (\\) and two \"quotes\""
9102 Used adaptation_meta header values may be logged via %note
9103 logformat code. If multiple adaptation_meta headers with the same name
9104 are used during master transaction lifetime, the header values are
9105 logged in the order they were used and duplicate values are ignored
9106 (only the first repeated value will be logged).
9112 LOC: Adaptation::Icap::TheConfig.repeat
9113 DEFAULT_IF_NONE: deny all
9115 This ACL determines which retriable ICAP transactions are
9116 retried. Transactions that received a complete ICAP response
9117 and did not have to consume or produce HTTP bodies to receive
9118 that response are usually retriable.
9120 icap_retry allow|deny [!]aclname ...
9122 Squid automatically retries some ICAP I/O timeouts and errors
9123 due to persistent connection race conditions.
9125 See also: icap_retry_limit
9128 NAME: icap_retry_limit
9131 LOC: Adaptation::Icap::TheConfig.repeat_limit
9133 DEFAULT_DOC: No retries are allowed.
9135 Limits the number of retries allowed.
9137 Communication errors due to persistent connection race
9138 conditions are unavoidable, automatically retried, and do not
9139 count against this limit.
9141 See also: icap_retry
9147 -----------------------------------------------------------------------------
9150 NAME: check_hostnames
9153 LOC: Config.onoff.check_hostnames
9155 For security and stability reasons Squid can check
9156 hostnames for Internet standard RFC compliance. If you want
9157 Squid to perform these checks turn this directive on.
9160 NAME: allow_underscore
9163 LOC: Config.onoff.allow_underscore
9165 Underscore characters is not strictly allowed in Internet hostnames
9166 but nevertheless used by many sites. Set this to off if you want
9167 Squid to be strict about the standard.
9168 This check is performed only when check_hostnames is set to on.
9171 NAME: dns_retransmit_interval
9174 LOC: Config.Timeout.idns_retransmit
9176 Initial retransmit interval for DNS queries. The interval is
9177 doubled each time all configured DNS servers have been tried.
9183 LOC: Config.Timeout.idns_query
9185 DNS Query timeout. If no response is received to a DNS query
9186 within this time all DNS servers for the queried domain
9187 are assumed to be unavailable.
9190 NAME: dns_packet_max
9192 DEFAULT_DOC: EDNS disabled
9194 LOC: Config.dns.packet_max
9196 Maximum number of bytes packet size to advertise via EDNS.
9197 Set to "none" to disable EDNS large packet support.
9199 For legacy reasons DNS UDP replies will default to 512 bytes which
9200 is too small for many responses. EDNS provides a means for Squid to
9201 negotiate receiving larger responses back immediately without having
9202 to failover with repeat requests. Responses larger than this limit
9203 will retain the old behaviour of failover to TCP DNS.
9205 Squid has no real fixed limit internally, but allowing packet sizes
9206 over 1500 bytes requires network jumbogram support and is usually not
9209 WARNING: The RFC also indicates that some older resolvers will reply
9210 with failure of the whole request if the extension is added. Some
9211 resolvers have already been identified which will reply with mangled
9212 EDNS response on occasion. Usually in response to many-KB jumbogram
9213 sizes being advertised by Squid.
9214 Squid will currently treat these both as an unable-to-resolve domain
9215 even if it would be resolvable without EDNS.
9222 DEFAULT_DOC: Search for single-label domain names is disabled.
9223 LOC: Config.onoff.res_defnames
9225 Normally the RES_DEFNAMES resolver option is disabled
9226 (see res_init(3)). This prevents caches in a hierarchy
9227 from interpreting single-component hostnames locally. To allow
9228 Squid to handle single-component names, enable this option.
9231 NAME: dns_multicast_local
9235 DEFAULT_DOC: Search for .local and .arpa names is disabled.
9236 LOC: Config.onoff.dns_mdns
9238 When set to on, Squid sends multicast DNS lookups on the local
9239 network for domains ending in .local and .arpa.
9240 This enables local servers and devices to be contacted in an
9241 ad-hoc or zero-configuration network environment.
9244 NAME: dns_nameservers
9247 DEFAULT_DOC: Use operating system definitions
9248 LOC: Config.dns_nameservers
9250 Use this if you want to specify a list of DNS name servers
9251 (IP addresses) to use instead of those given in your
9252 /etc/resolv.conf file.
9254 On Windows platforms, if no value is specified here or in
9255 the /etc/resolv.conf file, the list of DNS name servers are
9256 taken from the Windows registry, both static and dynamic DHCP
9257 configurations are supported.
9259 Example: dns_nameservers 10.0.0.1 192.172.0.4
9264 DEFAULT: @DEFAULT_HOSTS@
9265 LOC: Config.etcHostsPath
9267 Location of the host-local IP name-address associations
9268 database. Most Operating Systems have such a file on different
9270 - Un*X & Linux: /etc/hosts
9271 - Windows NT/2000: %SystemRoot%\system32\drivers\etc\hosts
9272 (%SystemRoot% value install default is c:\winnt)
9273 - Windows XP/2003: %SystemRoot%\system32\drivers\etc\hosts
9274 (%SystemRoot% value install default is c:\windows)
9275 - Windows 9x/Me: %windir%\hosts
9276 (%windir% value is usually c:\windows)
9277 - Cygwin: /etc/hosts
9279 The file contains newline-separated definitions, in the
9280 form ip_address_in_dotted_form name [name ...] names are
9281 whitespace-separated. Lines beginning with an hash (#)
9282 character are comments.
9284 The file is checked at startup and upon configuration.
9285 If set to 'none', it won't be checked.
9286 If append_domain is used, that domain will be added to
9287 domain-local (i.e. not containing any dot character) host
9293 LOC: Config.appendDomain
9295 DEFAULT_DOC: Use operating system definitions
9297 Appends local domain name to hostnames without any dots in
9298 them. append_domain must begin with a period.
9300 Be warned there are now Internet names with no dots in
9301 them using only top-domain names, so setting this may
9302 cause some Internet sites to become unavailable.
9305 append_domain .yourdomain.com
9308 NAME: ignore_unknown_nameservers
9310 LOC: Config.onoff.ignore_unknown_nameservers
9313 By default Squid checks that DNS responses are received
9314 from the same IP addresses they are sent to. If they
9315 don't match, Squid ignores the response and writes a warning
9316 message to cache.log. You can allow responses from unknown
9317 nameservers by setting this option to 'off'.
9323 LOC: Config.dns.v4_first
9325 With the IPv6 Internet being as fast or faster than IPv4 Internet
9326 for most networks Squid prefers to contact websites over IPv6.
9328 This option reverses the order of preference to make Squid contact
9329 dual-stack websites over IPv4 first. Squid will still perform both
9330 IPv6 and IPv4 DNS lookups before connecting.
9333 This option will restrict the situations under which IPv6
9334 connectivity is used (and tested). Hiding network problems
9335 which would otherwise be detected and warned about.
9339 COMMENT: (number of entries)
9342 LOC: Config.ipcache.size
9344 Maximum number of DNS IP cache entries.
9351 LOC: Config.ipcache.low
9358 LOC: Config.ipcache.high
9360 The size, low-, and high-water marks for the IP cache.
9363 NAME: fqdncache_size
9364 COMMENT: (number of entries)
9367 LOC: Config.fqdncache.size
9369 Maximum number of FQDN cache entries.
9374 -----------------------------------------------------------------------------
9377 NAME: configuration_includes_quoted_values
9379 TYPE: configuration_includes_quoted_values
9381 LOC: ConfigParser::RecognizeQuotedValues
9383 If set, Squid will recognize each "quoted string" after a configuration
9384 directive as a single parameter. The quotes are stripped before the
9385 parameter value is interpreted or used.
9386 See "Values with spaces, quotes, and other special characters"
9387 section for more details.
9394 LOC: Config.onoff.mem_pools
9396 If set, Squid will keep pools of allocated (but unused) memory
9397 available for future use. If memory is a premium on your
9398 system and you believe your malloc library outperforms Squid
9399 routines, disable this.
9402 NAME: memory_pools_limit
9406 LOC: Config.MemPools.limit
9408 Used only with memory_pools on:
9409 memory_pools_limit 50 MB
9411 If set to a non-zero value, Squid will keep at most the specified
9412 limit of allocated (but unused) memory in memory pools. All free()
9413 requests that exceed this limit will be handled by your malloc
9414 library. Squid does not pre-allocate any memory, just safe-keeps
9415 objects that otherwise would be free()d. Thus, it is safe to set
9416 memory_pools_limit to a reasonably high value even if your
9417 configuration will use less memory.
9419 If set to none, Squid will keep all memory it can. That is, there
9420 will be no limit on the total amount of memory used for safe-keeping.
9422 To disable memory allocation optimization, do not set
9423 memory_pools_limit to 0 or none. Set memory_pools to "off" instead.
9425 An overhead for maintaining memory pools is not taken into account
9426 when the limit is checked. This overhead is close to four bytes per
9427 object kept. However, pools may actually _save_ memory because of
9428 reduced memory thrashing in your malloc library.
9432 COMMENT: on|off|transparent|truncate|delete
9435 LOC: opt_forwarded_for
9437 If set to "on", Squid will append your client's IP address
9438 in the HTTP requests it forwards. By default it looks like:
9440 X-Forwarded-For: 192.1.2.3
9442 If set to "off", it will appear as
9444 X-Forwarded-For: unknown
9446 If set to "transparent", Squid will not alter the
9447 X-Forwarded-For header in any way.
9449 If set to "delete", Squid will delete the entire
9450 X-Forwarded-For header.
9452 If set to "truncate", Squid will remove all existing
9453 X-Forwarded-For entries, and place the client IP as the sole entry.
9456 NAME: cachemgr_passwd
9457 TYPE: cachemgrpasswd
9459 DEFAULT_DOC: No password. Actions which require password are denied.
9460 LOC: Config.passwd_list
9462 Specify passwords for cachemgr operations.
9464 Usage: cachemgr_passwd password action action ...
9466 Some valid actions are (see cache manager menu for a full list):
9506 * Indicates actions which will not be performed without a
9507 valid password, others can be performed if not listed here.
9509 To disable an action, set the password to "disable".
9510 To allow performing an action without a password, set the
9513 Use the keyword "all" to set the same password for all actions.
9516 cachemgr_passwd secret shutdown
9517 cachemgr_passwd lesssssssecret info stats/objects
9518 cachemgr_passwd disable all
9525 LOC: Config.onoff.client_db
9527 If you want to disable collecting per-client statistics,
9528 turn off client_db here.
9531 NAME: refresh_all_ims
9535 LOC: Config.onoff.refresh_all_ims
9537 When you enable this option, squid will always check
9538 the origin server for an update when a client sends an
9539 If-Modified-Since request. Many browsers use IMS
9540 requests when the user requests a reload, and this
9541 ensures those clients receive the latest version.
9543 By default (off), squid may return a Not Modified response
9544 based on the age of the cached version.
9547 NAME: reload_into_ims
9548 IFDEF: USE_HTTP_VIOLATIONS
9552 LOC: Config.onoff.reload_into_ims
9554 When you enable this option, client no-cache or ``reload''
9555 requests will be changed to If-Modified-Since requests.
9556 Doing this VIOLATES the HTTP standard. Enabling this
9557 feature could make you liable for problems which it
9560 see also refresh_pattern for a more selective approach.
9563 NAME: connect_retries
9565 LOC: Config.connect_retries
9567 DEFAULT_DOC: Do not retry failed connections.
9569 This sets the maximum number of connection attempts made for each
9570 TCP connection. The connect_retries attempts must all still
9571 complete within the connection timeout period.
9573 The default is not to re-try if the first connection attempt fails.
9574 The (not recommended) maximum is 10 tries.
9576 A warning message will be generated if it is set to a too-high
9577 value and the configured value will be over-ridden.
9579 Note: These re-tries are in addition to forward_max_tries
9580 which limit how many different addresses may be tried to find
9584 NAME: retry_on_error
9586 LOC: Config.retry.onerror
9589 If set to ON Squid will automatically retry requests when
9590 receiving an error response with status 403 (Forbidden),
9591 500 (Internal Error), 501 or 503 (Service not available).
9592 Status 502 and 504 (Gateway errors) are always retried.
9594 This is mainly useful if you are in a complex cache hierarchy to
9595 work around access control errors.
9597 NOTE: This retry will attempt to find another working destination.
9598 Which is different from the server which just failed.
9601 NAME: as_whois_server
9603 LOC: Config.as_whois_server
9604 DEFAULT: whois.ra.net
9606 WHOIS server to query for AS numbers. NOTE: AS numbers are
9607 queried only when Squid starts up, not for every request.
9612 LOC: Config.onoff.offline
9615 Enable this option and Squid will never try to validate cached
9619 NAME: uri_whitespace
9620 TYPE: uri_whitespace
9621 LOC: Config.uri_whitespace
9624 What to do with requests that have whitespace characters in the
9627 strip: The whitespace characters are stripped out of the URL.
9628 This is the behavior recommended by RFC2396 and RFC3986
9629 for tolerant handling of generic URI.
9630 NOTE: This is one difference between generic URI and HTTP URLs.
9632 deny: The request is denied. The user receives an "Invalid
9634 This is the behaviour recommended by RFC2616 for safe
9635 handling of HTTP request URL.
9637 allow: The request is allowed and the URI is not changed. The
9638 whitespace characters remain in the URI. Note the
9639 whitespace is passed to redirector processes if they
9641 Note this may be considered a violation of RFC2616
9642 request parsing where whitespace is prohibited in the
9645 encode: The request is allowed and the whitespace characters are
9646 encoded according to RFC1738.
9648 chop: The request is allowed and the URI is chopped at the
9652 NOTE the current Squid implementation of encode and chop violates
9653 RFC2616 by not using a 301 redirect after altering the URL.
9658 LOC: Config.chroot_dir
9661 Specifies a directory where Squid should do a chroot() while
9662 initializing. This also causes Squid to fully drop root
9663 privileges after initializing. This means, for example, if you
9664 use a HTTP port less than 1024 and try to reconfigure, you may
9665 get an error saying that Squid can not open the port.
9668 NAME: balance_on_multiple_ip
9670 LOC: Config.onoff.balance_on_multiple_ip
9673 Modern IP resolvers in squid sort lookup results by preferred access.
9674 By default squid will use these IP in order and only rotates to
9675 the next listed when the most preffered fails.
9677 Some load balancing servers based on round robin DNS have been
9678 found not to preserve user session state across requests
9679 to different IP addresses.
9681 Enabling this directive Squid rotates IP's per request.
9684 NAME: pipeline_prefetch
9685 TYPE: pipelinePrefetch
9686 LOC: Config.pipeline_max_prefetch
9688 DEFAULT_DOC: Do not pre-parse pipelined requests.
9690 HTTP clients may send a pipeline of 1+N requests to Squid using a
9691 single connection, without waiting for Squid to respond to the first
9692 of those requests. This option limits the number of concurrent
9693 requests Squid will try to handle in parallel. If set to N, Squid
9694 will try to receive and process up to 1+N requests on the same
9695 connection concurrently.
9697 Defaults to 0 (off) for bandwidth management and access logging
9700 NOTE: pipelining requires persistent connections to clients.
9702 WARNING: pipelining breaks NTLM and Negotiate/Kerberos authentication.
9705 NAME: high_response_time_warning
9708 LOC: Config.warnings.high_rptm
9710 DEFAULT_DOC: disabled.
9712 If the one-minute median response time exceeds this value,
9713 Squid prints a WARNING with debug level 0 to get the
9714 administrators attention. The value is in milliseconds.
9717 NAME: high_page_fault_warning
9719 LOC: Config.warnings.high_pf
9721 DEFAULT_DOC: disabled.
9723 If the one-minute average page fault rate exceeds this
9724 value, Squid prints a WARNING with debug level 0 to get
9725 the administrators attention. The value is in page faults
9729 NAME: high_memory_warning
9731 LOC: Config.warnings.high_memory
9732 IFDEF: HAVE_MSTATS&&HAVE_GNUMALLOC_H
9734 DEFAULT_DOC: disabled.
9736 If the memory usage (as determined by gnumalloc, if available and used)
9737 exceeds this amount, Squid prints a WARNING with debug level 0 to get
9738 the administrators attention.
9740 # TODO: link high_memory_warning to mempools?
9742 NAME: sleep_after_fork
9743 COMMENT: (microseconds)
9745 LOC: Config.sleep_after_fork
9748 When this is set to a non-zero value, the main Squid process
9749 sleeps the specified number of microseconds after a fork()
9750 system call. This sleep may help the situation where your
9751 system reports fork() failures due to lack of (virtual)
9752 memory. Note, however, if you have a lot of child
9753 processes, these sleep delays will add up and your
9754 Squid will not service requests for some amount of time
9755 until all the child processes have been started.
9756 On Windows value less then 1000 (1 milliseconds) are
9760 NAME: windows_ipaddrchangemonitor
9761 IFDEF: _SQUID_WINDOWS_
9765 LOC: Config.onoff.WIN32_IpAddrChangeMonitor
9767 On Windows Squid by default will monitor IP address changes and will
9768 reconfigure itself after any detected event. This is very useful for
9769 proxies connected to internet with dial-up interfaces.
9770 In some cases (a Proxy server acting as VPN gateway is one) it could be
9771 desiderable to disable this behaviour setting this to 'off'.
9772 Note: after changing this, Squid service must be restarted.
9777 IFDEF: USE_SQUID_EUI
9779 LOC: Eui::TheConfig.euiLookup
9781 Whether to lookup the EUI or MAC address of a connected client.
9784 NAME: max_filedescriptors max_filedesc
9787 DEFAULT_DOC: Use operating system limits set by ulimit.
9788 LOC: Config.max_filedescriptors
9790 Reduce the maximum number of filedescriptors supported below
9791 the usual operating system defaults.
9793 Remove from squid.conf to inherit the current ulimit setting.
9795 Note: Changing this requires a restart of Squid. Also
9796 not all I/O types supports large values (eg on Windows).
9799 NAME: force_request_body_continuation
9801 LOC: Config.accessList.forceRequestBodyContinuation
9803 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
9805 This option controls how Squid handles data upload requests from HTTP
9806 and FTP agents that require a "Please Continue" control message response
9807 to actually send the request body to Squid. It is mostly useful in
9808 adaptation environments.
9810 When Squid receives an HTTP request with an "Expect: 100-continue"
9811 header or an FTP upload command (e.g., STOR), Squid normally sends the
9812 request headers or FTP command information to an adaptation service (or
9813 peer) and waits for a response. Most adaptation services (and some
9814 broken peers) may not respond to Squid at that stage because they may
9815 decide to wait for the HTTP request body or FTP data transfer. However,
9816 that request body or data transfer may never come because Squid has not
9817 responded with the HTTP 100 or FTP 150 (Please Continue) control message
9818 to the request sender yet!
9820 An allow match tells Squid to respond with the HTTP 100 or FTP 150
9821 (Please Continue) control message on its own, before forwarding the
9822 request to an adaptation service or peer. Such a response usually forces
9823 the request sender to proceed with sending the body. A deny match tells
9824 Squid to delay that control response until the origin server confirms
9825 that the request body is needed. Delaying is the default behavior.
9828 NAME: server_pconn_for_nonretriable
9831 DEFAULT_DOC: Open new connections for forwarding requests Squid cannot retry safely.
9832 LOC: Config.accessList.serverPconnForNonretriable
9834 This option provides fine-grained control over persistent connection
9835 reuse when forwarding HTTP requests that Squid cannot retry. It is useful
9836 in environments where opening new connections is very expensive
9837 (e.g., all connections are secured with TLS with complex client and server
9838 certificate validation) and race conditions associated with persistent
9839 connections are very rare and/or only cause minor problems.
9841 HTTP prohibits retrying unsafe and non-idempotent requests (e.g., POST).
9842 Squid limitations also prohibit retrying all requests with bodies (e.g., PUT).
9843 By default, when forwarding such "risky" requests, Squid opens a new
9844 connection to the server or cache_peer, even if there is an idle persistent
9845 connection available. When Squid is configured to risk sending a non-retriable
9846 request on a previously used persistent connection, and the server closes
9847 the connection before seeing that risky request, the user gets an error response
9848 from Squid. In most cases, that error response will be HTTP 502 (Bad Gateway)
9849 with ERR_ZERO_SIZE_OBJECT or ERR_WRITE_ERROR (peer connection reset) error detail.
9851 If an allow rule matches, Squid reuses an available idle persistent connection
9852 (if any) for the request that Squid cannot retry. If a deny rule matches, then
9853 Squid opens a new connection for the request that Squid cannot retry.
9855 This option does not affect requests that Squid can retry. They will reuse idle
9856 persistent connections (if any).
9858 This clause only supports fast acl types.
9859 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
9862 acl SpeedIsWorthTheRisk method POST
9863 server_pconn_for_nonretriable allow SpeedIsWorthTheRisk
projects / thirdparty / squid.git / blob