1 ## Copyright (C) 1996-2015 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 # options still not yet ported from 2.7 to 3.x
115 NAME: broken_vary_encoding
118 This option is not yet supported by Squid-3.
124 This option is not yet supported by Squid-3.
130 This option is not yet supported by Squid-3.
133 NAME: external_refresh_check
136 This option is not yet supported by Squid-3.
139 NAME: location_rewrite_program location_rewrite_access location_rewrite_children location_rewrite_concurrency
142 This option is not yet supported by Squid-3.
145 NAME: refresh_stale_hit
148 This option is not yet supported by Squid-3.
151 # Options removed in 3.6
152 NAME: cache_peer_domain cache_host_domain
155 Replace with dstdomain ACLs and cache_peer_access.
158 NAME: sslproxy_cafile
161 Remove this line. Use tls_outgoing_options cafile= instead.
164 NAME: sslproxy_capath
167 Remove this line. Use tls_outgoing_options capath= instead.
170 NAME: sslproxy_cipher
173 Remove this line. Use tls_outgoing_options cipher= instead.
176 NAME: sslproxy_client_certificate
179 Remove this line. Use tls_outgoing_options cert= instead.
182 NAME: sslproxy_client_key
185 Remove this line. Use tls_outgoing_options key= instead.
191 Remove this line. Use tls_outgoing_options flags= instead.
194 NAME: sslproxy_options
197 Remove this line. Use tls_outgoing_options options= instead.
200 NAME: sslproxy_version
203 Remove this line. Use tls_outgoing_options options= instead.
206 # Options removed in 3.5
207 NAME: hierarchy_stoplist
210 Remove this line. Use always_direct or cache_peer_access ACLs instead if you need to prevent cache_peer use.
213 # Options removed in 3.4
217 Remove this line. Use acls with access_log directives to control access logging
223 Remove this line. Use acls with icap_log directives to control icap logging
226 # Options Removed in 3.3
227 NAME: ignore_ims_on_miss
230 Remove this line. The HTTP/1.1 feature is now configured by 'cache_miss_revalidate'.
233 # Options Removed in 3.2
234 NAME: chunked_request_body_max_size
237 Remove this line. Squid is now HTTP/1.1 compliant.
240 NAME: dns_v4_fallback
243 Remove this line. Squid performs a 'Happy Eyeballs' algorithm, the 'fallback' algorithm is no longer relevant.
246 NAME: emulate_httpd_log
249 Replace this with an access_log directive using the format 'common' or 'combined'.
255 Use a regular access.log with ACL limiting it to MISS events.
261 Remove this line. Configure FTP page display using the CSS controls in errorpages.css instead.
264 NAME: ignore_expect_100
267 Remove this line. The HTTP/1.1 feature is now fully supported by default.
273 Remove this option from your config. To log FQDN use %>A in the log format.
276 NAME: log_ip_on_direct
279 Remove this option from your config. To log server or peer names use %<A in the log format.
282 NAME: maximum_single_addr_tries
285 Replaced by connect_retries. The behaviour has changed, please read the documentation before altering.
288 NAME: referer_log referrer_log
291 Replace this with an access_log directive using the format 'referrer'.
297 Remove this line. The feature is supported by default in storage types where update is implemented.
300 NAME: url_rewrite_concurrency
303 Remove this line. Set the 'concurrency=' option of url_rewrite_children instead.
309 Replace this with an access_log directive using the format 'useragent'.
312 # Options Removed in 3.1
316 Remove this line. DNS is no longer tested on startup.
319 NAME: extension_methods
322 Remove this line. All valid methods for HTTP are accepted by default.
325 # 2.7 Options Removed/Replaced in 3.2
330 # 2.7 Options Removed/Replaced in 3.1
338 Remove this line. HTTP/1.1 is supported by default.
341 NAME: upgrade_http0.9
344 Remove this line. ICY/1.0 streaming protocol is supported by default.
347 NAME: zph_local zph_mode zph_option zph_parent zph_sibling
350 Alter these entries. Use the qos_flows directive instead.
353 # Options Removed in 3.0
357 Since squid-3.0 replace with request_header_access or reply_header_access
358 depending on whether you wish to match client requests or server replies.
361 NAME: httpd_accel_no_pmtu_disc
364 Since squid-3.0 use the 'disable-pmtu-discovery' flag on http_port instead.
367 NAME: wais_relay_host
370 Replace this line with 'cache_peer' configuration.
373 NAME: wais_relay_port
376 Replace this line with 'cache_peer' configuration.
381 -----------------------------------------------------------------------------
388 DEFAULT_DOC: SMP support disabled.
390 Number of main Squid processes or "workers" to fork and maintain.
391 0: "no daemon" mode, like running "squid -N ..."
392 1: "no SMP" mode, start one main Squid process daemon (default)
393 N: start N main Squid process daemons (i.e., SMP mode)
395 In SMP mode, each worker does nearly all what a single Squid daemon
396 does (e.g., listen on http_port and forward HTTP requests).
399 NAME: cpu_affinity_map
401 LOC: Config.cpuAffinityMap
403 DEFAULT_DOC: Let operating system decide.
405 Usage: cpu_affinity_map process_numbers=P1,P2,... cores=C1,C2,...
407 Sets 1:1 mapping between Squid processes and CPU cores. For example,
409 cpu_affinity_map process_numbers=1,2,3,4 cores=1,3,5,7
411 affects processes 1 through 4 only and places them on the first
412 four even cores, starting with core #1.
414 CPU cores are numbered starting from 1. Requires support for
415 sched_getaffinity(2) and sched_setaffinity(2) system calls.
417 Multiple cpu_affinity_map options are merged.
423 OPTIONS FOR AUTHENTICATION
424 -----------------------------------------------------------------------------
433 This is used to define parameters for the various authentication
434 schemes supported by Squid.
436 format: auth_param scheme parameter [setting]
438 The order in which authentication schemes are presented to the client is
439 dependent on the order the scheme first appears in config file. IE
440 has a bug (it's not RFC 2617 compliant) in that it will use the basic
441 scheme if basic is the first entry presented, even if more secure
442 schemes are presented. For now use the order in the recommended
443 settings section below. If other browsers have difficulties (don't
444 recognize the schemes offered even if you are using basic) either
445 put basic first, or disable the other schemes (by commenting out their
448 Once an authentication scheme is fully configured, it can only be
449 shutdown by shutting squid down and restarting. Changes can be made on
450 the fly and activated with a reconfigure. I.E. You can change to a
451 different helper, but not unconfigure the helper completely.
453 Please note that while this directive defines how Squid processes
454 authentication it does not automatically activate authentication.
455 To use authentication you must in addition make use of ACLs based
456 on login name in http_access (proxy_auth, proxy_auth_regex or
457 external with %LOGIN used in the format tag). The browser will be
458 challenged for authentication on the first such acl encountered
459 in http_access processing and will also be re-challenged for new
460 login credentials if the request is being denied by a proxy_auth
463 WARNING: authentication can't be used in a transparently intercepting
464 proxy as the client then thinks it is talking to an origin server and
465 not the proxy. This is a limitation of bending the TCP/IP protocol to
466 transparently intercepting port 80, not a limitation in Squid.
467 Ports flagged 'transparent', 'intercept', or 'tproxy' have
468 authentication disabled.
470 === Parameters common to all schemes. ===
473 Specifies the command for the external authenticator.
475 By default, each authentication scheme is not used unless a
476 program is specified.
478 See http://wiki.squid-cache.org/Features/AddonHelpers for
479 more details on helper operations and creating your own.
482 Specifies a string to be append to request line format for
483 the authentication helper. "Quoted" format values may contain
484 spaces and logformat %macros. In theory, any logformat %macro
485 can be used. In practice, a %macro expands as a dash (-) if
486 the helper request is sent before the required macro
487 information is available to Squid.
489 By default, Squid uses request formats provided in
490 scheme-specific examples below (search for %credentials).
492 The expanded key_extras value is added to the Squid credentials
493 cache and, hence, will affect authentication. It can be used to
494 autenticate different users with identical user names (e.g.,
495 when user authentication depends on http_port).
497 Avoid adding frequently changing information to key_extras. For
498 example, if you add user source IP, and it changes frequently
499 in your environment, then max_user_ip ACL is going to treat
500 every user+IP combination as a unique "user", breaking the ACL
501 and wasting a lot of memory on those user records. It will also
502 force users to authenticate from scratch whenever their IP
506 Specifies the protection scope (aka realm name) which is to be
507 reported to the client for the authentication scheme. It is
508 commonly part of the text the user will see when prompted for
509 their username and password.
511 For Basic the default is "Squid proxy-caching web server".
512 For Digest there is no default, this parameter is mandatory.
513 For NTLM and Negotiate this parameter is ignored.
515 "children" numberofchildren [startup=N] [idle=N] [concurrency=N] [queue-size=N]
517 The maximum number of authenticator processes to spawn. If
518 you start too few Squid will have to wait for them to process
519 a backlog of credential verifications, slowing it down. When
520 password verifications are done via a (slow) network you are
521 likely to need lots of authenticator processes.
523 The startup= and idle= options permit some skew in the exact
524 amount run. A minimum of startup=N will begin during startup
525 and reconfigure. Squid will start more in groups of up to
526 idle=N in an attempt to meet traffic needs and to keep idle=N
527 free above those traffic needs up to the maximum.
529 The concurrency= option sets the number of concurrent requests
530 the helper can process. The default of 0 is used for helpers
531 who only supports one request at a time. Setting this to a
532 number greater than 0 changes the protocol used to include a
533 channel ID field first on the request/response line, allowing
534 multiple requests to be sent to the same helper in parallel
535 without waiting for the response.
537 Concurrency must not be set unless it's known the helper
538 supports the input format with channel-ID fields.
540 The queue-size= option sets the maximum number of queued
541 requests. If the queued requests exceed queue size for more
542 than 3 minutes then squid aborts its operation.
543 The default value is set to 2*numberofchildren/
545 NOTE: NTLM and Negotiate schemes do not support concurrency
546 in the Squid code module even though some helpers can.
549 IF HAVE_AUTH_MODULE_BASIC
550 === Basic authentication parameters ===
553 HTTP uses iso-latin-1 as character set, while some
554 authentication backends such as LDAP expects UTF-8. If this is
555 set to on Squid will translate the HTTP iso-latin-1 charset to
556 UTF-8 before sending the username and password to the helper.
558 "credentialsttl" timetolive
559 Specifies how long squid assumes an externally validated
560 username:password pair is valid for - in other words how
561 often the helper program is called for that user. Set this
562 low to force revalidation with short lived passwords.
564 NOTE: setting this high does not impact your susceptibility
565 to replay attacks unless you are using an one-time password
566 system (such as SecureID). If you are using such a system,
567 you will be vulnerable to replay attacks unless you also
568 use the max_user_ip ACL in an http_access rule.
570 "casesensitive" on|off
571 Specifies if usernames are case sensitive. Most user databases
572 are case insensitive allowing the same username to be spelled
573 using both lower and upper case letters, but some are case
574 sensitive. This makes a big difference for user_max_ip ACL
575 processing and similar.
578 IF HAVE_AUTH_MODULE_DIGEST
579 === Digest authentication parameters ===
582 HTTP uses iso-latin-1 as character set, while some
583 authentication backends such as LDAP expects UTF-8. If this is
584 set to on Squid will translate the HTTP iso-latin-1 charset to
585 UTF-8 before sending the username and password to the helper.
587 "nonce_garbage_interval" timeinterval
588 Specifies the interval that nonces that have been issued
589 to client_agent's are checked for validity.
591 "nonce_max_duration" timeinterval
592 Specifies the maximum length of time a given nonce will be
595 "nonce_max_count" number
596 Specifies the maximum number of times a given nonce can be
599 "nonce_strictness" on|off
600 Determines if squid requires strict increment-by-1 behavior
601 for nonce counts, or just incrementing (off - for use when
602 user agents generate nonce counts that occasionally miss 1
603 (ie, 1,2,4,6)). Default off.
605 "check_nonce_count" on|off
606 This directive if set to off can disable the nonce count check
607 completely to work around buggy digest qop implementations in
608 certain mainstream browser versions. Default on to check the
609 nonce count to protect from authentication replay attacks.
611 "post_workaround" on|off
612 This is a workaround to certain buggy browsers who send an
613 incorrect request digest in POST requests when reusing the
614 same nonce as acquired earlier on a GET request.
617 IF HAVE_AUTH_MODULE_NEGOTIATE
618 === Negotiate authentication parameters ===
621 If you experience problems with PUT/POST requests when using
622 the this authentication scheme 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.
628 IF HAVE_AUTH_MODULE_NTLM
629 === NTLM authentication parameters ===
632 If you experience problems with PUT/POST requests when using
633 the this authentication scheme then you can try setting this
634 to off. This will cause Squid to forcibly close the connection
635 on the initial request where the browser asks which schemes
636 are supported by the proxy.
639 === Example Configuration ===
641 This configuration displays the recommended authentication scheme
642 order from most to least secure with recommended minimum configuration
643 settings for each scheme:
645 #auth_param negotiate program <uncomment and complete this line to activate>
646 #auth_param negotiate children 20 startup=0 idle=1
647 #auth_param negotiate keep_alive on
649 #auth_param digest program <uncomment and complete this line to activate>
650 #auth_param digest children 20 startup=0 idle=1
651 #auth_param digest realm Squid proxy-caching web server
652 #auth_param digest nonce_garbage_interval 5 minutes
653 #auth_param digest nonce_max_duration 30 minutes
654 #auth_param digest nonce_max_count 50
656 #auth_param ntlm program <uncomment and complete this line to activate>
657 #auth_param ntlm children 20 startup=0 idle=1
658 #auth_param ntlm keep_alive on
660 #auth_param basic program <uncomment and complete this line>
661 #auth_param basic children 5 startup=5 idle=1
662 #auth_param basic realm Squid proxy-caching web server
663 #auth_param basic credentialsttl 2 hours
666 NAME: authenticate_cache_garbage_interval
669 LOC: Config.authenticateGCInterval
671 The time period between garbage collection across the username cache.
672 This is a trade-off between memory utilization (long intervals - say
673 2 days) and CPU (short intervals - say 1 minute). Only change if you
677 NAME: authenticate_ttl
680 LOC: Config.authenticateTTL
682 The time a user & their credentials stay in the logged in
683 user cache since their last request. When the garbage
684 interval passes, all user credentials that have passed their
685 TTL are removed from memory.
688 NAME: authenticate_ip_ttl
690 LOC: Config.authenticateIpTTL
693 If you use proxy authentication and the 'max_user_ip' ACL,
694 this directive controls how long Squid remembers the IP
695 addresses associated with each user. Use a small value
696 (e.g., 60 seconds) if your users might change addresses
697 quickly, as is the case with dialup. You might be safe
698 using a larger value (e.g., 2 hours) in a corporate LAN
699 environment with relatively static address assignments.
704 -----------------------------------------------------------------------------
707 NAME: external_acl_type
708 TYPE: externalAclHelper
709 LOC: Config.externalAclHelperList
712 This option defines external acl classes using a helper program
713 to look up the status
715 external_acl_type name [options] FORMAT.. /path/to/helper [helper arguments..]
719 ttl=n TTL in seconds for cached results (defaults to 3600
723 TTL for cached negative lookups (default same
726 grace=n Percentage remaining of TTL where a refresh of a
727 cached entry should be initiated without needing to
728 wait for a new reply. (default is for no grace period)
730 cache=n Limit the result cache size, default is 262144.
731 The expanded FORMAT value is used as the cache key, so
732 if the details in FORMAT are highly variable a larger
733 cache may be needed to produce reduction in helper load.
736 Maximum number of acl helper processes spawned to service
737 external acl lookups of this type. (default 20)
740 Minimum number of acl helper processes to spawn during
741 startup and reconfigure to service external acl lookups
742 of this type. (default 0)
745 Number of acl helper processes to keep ahead of traffic
746 loads. Squid will spawn this many at once whenever load
747 rises above the capabilities of existing processes.
748 Up to the value of children-max. (default 1)
750 concurrency=n concurrency level per process. Only used with helpers
751 capable of processing more than one query at a time.
753 queue-size=N The queue-size= option sets the maximum number of queued
754 requests. If the queued requests exceed queue size
756 The default value is set to 2*children-max.
758 protocol=2.5 Compatibility mode for Squid-2.5 external acl helpers.
760 ipv4 / ipv6 IP protocol used to communicate with this helper.
761 The default is to auto-detect IPv6 and use it when available.
764 FORMAT is a series of %macro codes. See logformat directive for a full list
765 of the accepted codes. Although note that at the time of any external ACL
766 being tested data may not be available and thus some %macro expand to '-'.
768 In addition to the logformat codes; when processing external ACLs these
769 additional macros are made available:
771 %ACL The name of the ACL being tested.
773 %DATA The ACL arguments. If a logformat encoding modifier
774 is used it will encode the whole set of arguments
777 If not used; then any arguments are automatically
778 added at the end of the line sent to the helper
779 as separately URL-encoded fields.
781 If SSL is enabled, the following formating codes become available:
783 %USER_CERT SSL User certificate in PEM format
784 %USER_CERTCHAIN SSL User certificate chain in PEM format
785 %USER_CERT_xx SSL User certificate subject attribute xx
786 %USER_CA_CERT_xx SSL User certificate issuer attribute xx
789 NOTE: all other format codes accepted by older Squid versions
793 General request syntax:
795 [channel-ID] FORMAT-values [acl-values ...]
798 FORMAT-values consists of transaction details expanded with
799 whitespace separation per the config file FORMAT specification
800 using the FORMAT macros listed above.
802 acl-values consists of any string specified in the referencing
803 config 'acl ... external' line. see the "acl external" directive.
805 Request values sent to the helper are URL escaped to protect
806 each value in requests against whitespaces.
808 If using protocol=2.5 then the request sent to the helper is not
809 URL escaped to protect against whitespace.
811 NOTE: protocol=3.0 is deprecated as no longer necessary.
813 When using the concurrency= option the protocol is changed by
814 introducing a query channel tag in front of the request/response.
815 The query channel tag is a number between 0 and concurrency-1.
816 This value must be echoed back unchanged to Squid as the first part
817 of the response relating to its request.
820 The helper receives lines expanded per the above format specification
821 and for each input line returns 1 line starting with OK/ERR/BH result
822 code and optionally followed by additional keywords with more details.
825 General result syntax:
827 [channel-ID] result keyword=value ...
829 Result consists of one of the codes:
832 the ACL test produced a match.
835 the ACL test does not produce a match.
838 An internal error occurred in the helper, preventing
839 a result being identified.
841 The meaning of 'a match' is determined by your squid.conf
842 access control configuration. See the Squid wiki for details.
846 user= The users name (login)
848 password= The users password (for login= cache_peer option)
850 message= Message describing the reason for this response.
851 Available as %o in error pages.
852 Useful on (ERR and BH results).
854 tag= Apply a tag to a request. Only sets a tag once,
855 does not alter existing tags.
857 log= String to be logged in access.log. Available as
858 %ea in logformat specifications.
860 clt_conn_tag= Associates a TAG with the client TCP connection.
861 Please see url_rewrite_program related documentation
864 Any keywords may be sent on any response whether OK, ERR or BH.
866 All response keyword values need to be a single token with URL
867 escaping, or enclosed in double quotes (") and escaped using \ on
868 any double quotes or \ characters within the value. The wrapping
869 double quotes are removed before the value is interpreted by Squid.
870 \r and \n are also replace by CR and LF.
872 Some example key values:
876 user="J. \"Bob\" Smith"
883 DEFAULT: ssl::certHasExpired ssl_error X509_V_ERR_CERT_HAS_EXPIRED
884 DEFAULT: ssl::certNotYetValid ssl_error X509_V_ERR_CERT_NOT_YET_VALID
885 DEFAULT: ssl::certDomainMismatch ssl_error SQUID_X509_V_ERR_DOMAIN_MISMATCH
886 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
887 DEFAULT: ssl::certSelfSigned ssl_error X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT
890 DEFAULT: manager url_regex -i ^cache_object:// +i ^https?://[^/]+/squid-internal-mgr/
891 DEFAULT: localhost src 127.0.0.1/32 ::1
892 DEFAULT: to_localhost dst 127.0.0.0/8 0.0.0.0/32 ::1
893 DEFAULT_DOC: ACLs all, manager, localhost, and to_localhost are predefined.
895 Defining an Access List
897 Every access list definition must begin with an aclname and acltype,
898 followed by either type-specific arguments or a quoted filename that
901 acl aclname acltype argument ...
902 acl aclname acltype "file" ...
904 When using "file", the file should contain one item per line.
906 Some acl types supports options which changes their default behaviour.
907 The available options are:
909 -i,+i By default, regular expressions are CASE-SENSITIVE. To make them
910 case-insensitive, use the -i option. To return case-sensitive
911 use the +i option between patterns, or make a new ACL line
914 -n Disable lookups and address type conversions. If lookup or
915 conversion is required because the parameter type (IP or
916 domain name) does not match the message address type (domain
917 name or IP), then the ACL would immediately declare a mismatch
918 without any warnings or lookups.
920 -- Used to stop processing all options, in the case the first acl
921 value has '-' character as first character (for example the '-'
922 is a valid domain name)
924 Some acl types require suspending the current request in order
925 to access some external data source.
926 Those which do are marked with the tag [slow], those which
927 don't are marked as [fast].
928 See http://wiki.squid-cache.org/SquidFaq/SquidAcl
929 for further information
931 ***** ACL TYPES AVAILABLE *****
933 acl aclname src ip-address/mask ... # clients IP address [fast]
934 acl aclname src addr1-addr2/mask ... # range of addresses [fast]
935 acl aclname dst [-n] ip-address/mask ... # URL host's IP address [slow]
936 acl aclname localip ip-address/mask ... # IP address the client connected to [fast]
938 acl aclname arp mac-address ... (xx:xx:xx:xx:xx:xx notation)
940 # The 'arp' ACL code is not portable to all operating systems.
941 # It works on Linux, Solaris, Windows, FreeBSD, and some other
944 # NOTE: Squid can only determine the MAC/EUI address for IPv4
945 # clients that are on the same subnet. If the client is on a
946 # different subnet, then Squid cannot find out its address.
948 # NOTE 2: IPv6 protocol does not contain ARP. MAC/EUI is either
949 # encoded directly in the IPv6 address or not available.
951 acl aclname srcdomain .foo.com ...
952 # reverse lookup, from client IP [slow]
953 acl aclname dstdomain [-n] .foo.com ...
954 # Destination server from URL [fast]
955 acl aclname srcdom_regex [-i] \.foo\.com ...
956 # regex matching client name [slow]
957 acl aclname dstdom_regex [-n] [-i] \.foo\.com ...
958 # regex matching server [fast]
960 # For dstdomain and dstdom_regex a reverse lookup is tried if a IP
961 # based URL is used and no match is found. The name "none" is used
962 # if the reverse lookup fails.
964 acl aclname src_as number ...
965 acl aclname dst_as number ...
967 # Except for access control, AS numbers can be used for
968 # routing of requests to specific caches. Here's an
969 # example for routing all requests for AS#1241 and only
970 # those to mycache.mydomain.net:
971 # acl asexample dst_as 1241
972 # cache_peer_access mycache.mydomain.net allow asexample
973 # cache_peer_access mycache_mydomain.net deny all
975 acl aclname peername myPeer ...
977 # match against a named cache_peer entry
978 # set unique name= on cache_peer lines for reliable use.
980 acl aclname time [day-abbrevs] [h1:m1-h2:m2]
990 # h1:m1 must be less than h2:m2
992 acl aclname url_regex [-i] ^http:// ...
993 # regex matching on whole URL [fast]
994 acl aclname urllogin [-i] [^a-zA-Z0-9] ...
995 # regex matching on URL login field
996 acl aclname urlpath_regex [-i] \.gif$ ...
997 # regex matching on URL path [fast]
999 acl aclname port 80 70 21 0-1024... # destination TCP port [fast]
1001 acl aclname localport 3128 ... # TCP port the client connected to [fast]
1002 # NP: for interception mode this is usually '80'
1004 acl aclname myportname 3128 ... # *_port name [fast]
1006 acl aclname proto HTTP FTP ... # request protocol [fast]
1008 acl aclname method GET POST ... # HTTP request method [fast]
1010 acl aclname http_status 200 301 500- 400-403 ...
1011 # status code in reply [fast]
1013 acl aclname browser [-i] regexp ...
1014 # pattern match on User-Agent header (see also req_header below) [fast]
1016 acl aclname referer_regex [-i] regexp ...
1017 # pattern match on Referer header [fast]
1018 # Referer is highly unreliable, so use with care
1020 acl aclname ident username ...
1021 acl aclname ident_regex [-i] pattern ...
1022 # string match on ident output [slow]
1023 # use REQUIRED to accept any non-null ident.
1025 acl aclname proxy_auth [-i] username ...
1026 acl aclname proxy_auth_regex [-i] pattern ...
1027 # perform http authentication challenge to the client and match against
1028 # supplied credentials [slow]
1030 # takes a list of allowed usernames.
1031 # use REQUIRED to accept any valid username.
1033 # Will use proxy authentication in forward-proxy scenarios, and plain
1034 # http authenticaiton in reverse-proxy scenarios
1036 # NOTE: when a Proxy-Authentication header is sent but it is not
1037 # needed during ACL checking the username is NOT logged
1040 # NOTE: proxy_auth requires a EXTERNAL authentication program
1041 # to check username/password combinations (see
1042 # auth_param directive).
1044 # NOTE: proxy_auth can't be used in a transparent/intercepting proxy
1045 # as the browser needs to be configured for using a proxy in order
1046 # to respond to proxy authentication.
1048 acl aclname snmp_community string ...
1049 # A community string to limit access to your SNMP Agent [fast]
1052 # acl snmppublic snmp_community public
1054 acl aclname maxconn number
1055 # This will be matched when the client's IP address has
1056 # more than <number> TCP connections established. [fast]
1057 # NOTE: This only measures direct TCP links so X-Forwarded-For
1058 # indirect clients are not counted.
1060 acl aclname max_user_ip [-s] number
1061 # This will be matched when the user attempts to log in from more
1062 # than <number> different ip addresses. The authenticate_ip_ttl
1063 # parameter controls the timeout on the ip entries. [fast]
1064 # If -s is specified the limit is strict, denying browsing
1065 # from any further IP addresses until the ttl has expired. Without
1066 # -s Squid will just annoy the user by "randomly" denying requests.
1067 # (the counter is reset each time the limit is reached and a
1068 # request is denied)
1069 # NOTE: in acceleration mode or where there is mesh of child proxies,
1070 # clients may appear to come from multiple addresses if they are
1071 # going through proxy farms, so a limit of 1 may cause user problems.
1073 acl aclname random probability
1074 # Pseudo-randomly match requests. Based on the probability given.
1075 # Probability may be written as a decimal (0.333), fraction (1/3)
1076 # or ratio of matches:non-matches (3:5).
1078 acl aclname req_mime_type [-i] mime-type ...
1079 # regex match against the mime type of the request generated
1080 # by the client. Can be used to detect file upload or some
1081 # types HTTP tunneling requests [fast]
1082 # NOTE: This does NOT match the reply. You cannot use this
1083 # to match the returned file type.
1085 acl aclname req_header header-name [-i] any\.regex\.here
1086 # regex match against any of the known request headers. May be
1087 # thought of as a superset of "browser", "referer" and "mime-type"
1090 acl aclname rep_mime_type [-i] mime-type ...
1091 # regex match against the mime type of the reply received by
1092 # squid. Can be used to detect file download or some
1093 # types HTTP tunneling requests. [fast]
1094 # NOTE: This has no effect in http_access rules. It only has
1095 # effect in rules that affect the reply data stream such as
1096 # http_reply_access.
1098 acl aclname rep_header header-name [-i] any\.regex\.here
1099 # regex match against any of the known reply headers. May be
1100 # thought of as a superset of "browser", "referer" and "mime-type"
1103 acl aclname external class_name [arguments...]
1104 # external ACL lookup via a helper class defined by the
1105 # external_acl_type directive [slow]
1107 acl aclname user_cert attribute values...
1108 # match against attributes in a user SSL certificate
1109 # attribute is one of DN/C/O/CN/L/ST or a numerical OID [fast]
1111 acl aclname ca_cert attribute values...
1112 # match against attributes a users issuing CA SSL certificate
1113 # attribute is one of DN/C/O/CN/L/ST or a numerical OID [fast]
1115 acl aclname ext_user username ...
1116 acl aclname ext_user_regex [-i] pattern ...
1117 # string match on username returned by external acl helper [slow]
1118 # use REQUIRED to accept any non-null user name.
1120 acl aclname tag tagvalue ...
1121 # string match on tag returned by external acl helper [fast]
1122 # DEPRECATED. Only the first tag will match with this ACL.
1123 # Use the 'note' ACL instead for handling multiple tag values.
1125 acl aclname hier_code codename ...
1126 # string match against squid hierarchy code(s); [fast]
1127 # e.g., DIRECT, PARENT_HIT, NONE, etc.
1129 # NOTE: This has no effect in http_access rules. It only has
1130 # effect in rules that affect the reply data stream such as
1131 # http_reply_access.
1133 acl aclname note name [value ...]
1134 # match transaction annotation [fast]
1135 # Without values, matches any annotation with a given name.
1136 # With value(s), matches any annotation with a given name that
1137 # also has one of the given values.
1138 # Names and values are compared using a string equality test.
1139 # Annotation sources include note and adaptation_meta directives
1140 # as well as helper and eCAP responses.
1142 acl aclname adaptation_service service ...
1143 # Matches the name of any icap_service, ecap_service,
1144 # adaptation_service_set, or adaptation_service_chain that Squid
1145 # has used (or attempted to use) for the master transaction.
1146 # This ACL must be defined after the corresponding adaptation
1147 # service is named in squid.conf. This ACL is usable with
1148 # adaptation_meta because it starts matching immediately after
1149 # the service has been selected for adaptation.
1152 acl aclname ssl_error errorname
1153 # match against SSL certificate validation error [fast]
1155 # For valid error names see in @DEFAULT_ERROR_DIR@/templates/error-details.txt
1158 # The following can be used as shortcuts for certificate properties:
1159 # [ssl::]certHasExpired: the "not after" field is in the past
1160 # [ssl::]certNotYetValid: the "not before" field is in the future
1161 # [ssl::]certUntrusted: The certificate issuer is not to be trusted.
1162 # [ssl::]certSelfSigned: The certificate is self signed.
1163 # [ssl::]certDomainMismatch: The certificate CN domain does not
1164 # match the name the name of the host we are connecting to.
1166 # The ssl::certHasExpired, ssl::certNotYetValid, ssl::certDomainMismatch,
1167 # ssl::certUntrusted, and ssl::certSelfSigned can also be used as
1168 # predefined ACLs, just like the 'all' ACL.
1170 # NOTE: The ssl_error ACL is only supported with sslproxy_cert_error,
1171 # sslproxy_cert_sign, and sslproxy_cert_adapt options.
1173 acl aclname server_cert_fingerprint [-sha1] fingerprint
1174 # match against server SSL certificate fingerprint [fast]
1176 # The fingerprint is the digest of the DER encoded version
1177 # of the whole certificate. The user should use the form: XX:XX:...
1178 # Optional argument specifies the digest algorithm to use.
1179 # The SHA1 digest algorithm is the default and is currently
1180 # the only algorithm supported (-sha1).
1182 acl aclname at_step step
1183 # match against the current step during ssl_bump evaluation [fast]
1184 # Never matches and should not be used outside the ssl_bump context.
1186 # At each SslBump step, Squid evaluates ssl_bump directives to find
1187 # the next bumping action (e.g., peek or splice). Valid SslBump step
1188 # values and the corresponding ssl_bump evaluation moments are:
1189 # SslBump1: After getting TCP-level and HTTP CONNECT info.
1190 # SslBump2: After getting SSL Client Hello info.
1191 # SslBump3: After getting SSL Server Hello info.
1193 acl aclname ssl::server_name .foo.com ...
1194 # matches server name obtained from various sources [fast]
1196 # The server name is obtained during Ssl-Bump steps from such sources
1197 # as CONNECT request URI, client SNI, and SSL server certificate CN.
1198 # During each Ssl-Bump step, Squid may improve its understanding of a
1199 # "true server name". Unlike dstdomain, this ACL does not perform
1202 acl aclname ssl::server_name_regex [-i] \.foo\.com ...
1203 # regex matches server name obtained from various sources [fast]
1205 acl aclname any-of acl1 acl2 ...
1206 # match any one of the acls [fast or slow]
1207 # The first matching ACL stops further ACL evaluation.
1209 # ACLs from multiple any-of lines with the same name are ORed.
1210 # For example, A = (a1 or a2) or (a3 or a4) can be written as
1211 # acl A any-of a1 a2
1212 # acl A any-of a3 a4
1214 # This group ACL is fast if all evaluated ACLs in the group are fast
1215 # and slow otherwise.
1217 acl aclname all-of acl1 acl2 ...
1218 # match all of the acls [fast or slow]
1219 # The first mismatching ACL stops further ACL evaluation.
1221 # ACLs from multiple all-of lines with the same name are ORed.
1222 # For example, B = (b1 and b2) or (b3 and b4) can be written as
1223 # acl B all-of b1 b2
1224 # acl B all-of b3 b4
1226 # This group ACL is fast if all evaluated ACLs in the group are fast
1227 # and slow otherwise.
1230 acl macaddress arp 09:00:2b:23:45:67
1231 acl myexample dst_as 1241
1232 acl password proxy_auth REQUIRED
1233 acl fileupload req_mime_type -i ^multipart/form-data$
1234 acl javascript rep_mime_type -i ^application/x-javascript$
1238 # Recommended minimum configuration:
1241 # Example rule allowing access from your local networks.
1242 # Adapt to list your (internal) IP networks from where browsing
1244 acl localnet src 0.0.0.1-0.255.255.255 # RFC 1122 "this" network (LAN)
1245 acl localnet src 10.0.0.0/8 # RFC 1918 local private network (LAN)
1246 acl localnet src 100.64.0.0/10 # RFC 6598 shared address space (CGN)
1247 acl localhet src 169.254.0.0/16 # RFC 3927 link-local (directly plugged) machines
1248 acl localnet src 172.16.0.0/12 # RFC 1918 local private network (LAN)
1249 acl localnet src 192.168.0.0/16 # RFC 1918 local private network (LAN)
1250 acl localnet src fc00::/7 # RFC 4193 local private network range
1251 acl localnet src fe80::/10 # RFC 4291 link-local (directly plugged) machines
1253 acl SSL_ports port 443
1254 acl Safe_ports port 80 # http
1255 acl Safe_ports port 21 # ftp
1256 acl Safe_ports port 443 # https
1257 acl Safe_ports port 70 # gopher
1258 acl Safe_ports port 210 # wais
1259 acl Safe_ports port 1025-65535 # unregistered ports
1260 acl Safe_ports port 280 # http-mgmt
1261 acl Safe_ports port 488 # gss-http
1262 acl Safe_ports port 591 # filemaker
1263 acl Safe_ports port 777 # multiling http
1264 acl CONNECT method CONNECT
1268 NAME: proxy_protocol_access
1270 LOC: Config.accessList.proxyProtocol
1272 DEFAULT_DOC: all TCP connections to ports with require-proxy-header will be denied
1274 Determine which client proxies can be trusted to provide correct
1275 information regarding real client IP address using PROXY protocol.
1277 Requests may pass through a chain of several other proxies
1278 before reaching us. The original source details may by sent in:
1279 * HTTP message Forwarded header, or
1280 * HTTP message X-Forwarded-For header, or
1281 * PROXY protocol connection header.
1283 This directive is solely for validating new PROXY protocol
1284 connections received from a port flagged with require-proxy-header.
1285 It is checked only once after TCP connection setup.
1287 A deny match results in TCP connection closure.
1289 An allow match is required for Squid to permit the corresponding
1290 TCP connection, before Squid even looks for HTTP request headers.
1291 If there is an allow match, Squid starts using PROXY header information
1292 to determine the source address of the connection for all future ACL
1293 checks, logging, etc.
1295 SECURITY CONSIDERATIONS:
1297 Any host from which we accept client IP details can place
1298 incorrect information in the relevant header, and Squid
1299 will use the incorrect information as if it were the
1300 source address of the request. This may enable remote
1301 hosts to bypass any access control restrictions that are
1302 based on the client's source addresses.
1304 This clause only supports fast acl types.
1305 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1308 NAME: follow_x_forwarded_for
1310 IFDEF: FOLLOW_X_FORWARDED_FOR
1311 LOC: Config.accessList.followXFF
1312 DEFAULT_IF_NONE: deny all
1313 DEFAULT_DOC: X-Forwarded-For header will be ignored.
1315 Determine which client proxies can be trusted to provide correct
1316 information regarding real client IP address.
1318 Requests may pass through a chain of several other proxies
1319 before reaching us. The original source details may by sent in:
1320 * HTTP message Forwarded header, or
1321 * HTTP message X-Forwarded-For header, or
1322 * PROXY protocol connection header.
1324 PROXY protocol connections are controlled by the proxy_protocol_access
1325 directive which is checked before this.
1327 If a request reaches us from a source that is allowed by this
1328 directive, then we trust the information it provides regarding
1329 the IP of the client it received from (if any).
1331 For the purpose of ACLs used in this directive the src ACL type always
1332 matches the address we are testing and srcdomain matches its rDNS.
1334 On each HTTP request Squid checks for X-Forwarded-For header fields.
1335 If found the header values are iterated in reverse order and an allow
1336 match is required for Squid to continue on to the next value.
1337 The verification ends when a value receives a deny match, cannot be
1338 tested, or there are no more values to test.
1339 NOTE: Squid does not yet follow the Forwarded HTTP header.
1341 The end result of this process is an IP address that we will
1342 refer to as the indirect client address. This address may
1343 be treated as the client address for access control, ICAP, delay
1344 pools and logging, depending on the acl_uses_indirect_client,
1345 icap_uses_indirect_client, delay_pool_uses_indirect_client,
1346 log_uses_indirect_client and tproxy_uses_indirect_client options.
1348 This clause only supports fast acl types.
1349 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1351 SECURITY CONSIDERATIONS:
1353 Any host from which we accept client IP details can place
1354 incorrect information in the relevant header, and Squid
1355 will use the incorrect information as if it were the
1356 source address of the request. This may enable remote
1357 hosts to bypass any access control restrictions that are
1358 based on the client's source addresses.
1362 acl localhost src 127.0.0.1
1363 acl my_other_proxy srcdomain .proxy.example.com
1364 follow_x_forwarded_for allow localhost
1365 follow_x_forwarded_for allow my_other_proxy
1368 NAME: acl_uses_indirect_client
1371 IFDEF: FOLLOW_X_FORWARDED_FOR
1373 LOC: Config.onoff.acl_uses_indirect_client
1375 Controls whether the indirect client address
1376 (see follow_x_forwarded_for) is used instead of the
1377 direct client address in acl matching.
1379 NOTE: maxconn ACL considers direct TCP links and indirect
1380 clients will always have zero. So no match.
1383 NAME: delay_pool_uses_indirect_client
1386 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_DELAY_POOLS
1388 LOC: Config.onoff.delay_pool_uses_indirect_client
1390 Controls whether the indirect client address
1391 (see follow_x_forwarded_for) is used instead of the
1392 direct client address in delay pools.
1395 NAME: log_uses_indirect_client
1398 IFDEF: FOLLOW_X_FORWARDED_FOR
1400 LOC: Config.onoff.log_uses_indirect_client
1402 Controls whether the indirect client address
1403 (see follow_x_forwarded_for) is used instead of the
1404 direct client address in the access log.
1407 NAME: tproxy_uses_indirect_client
1410 IFDEF: FOLLOW_X_FORWARDED_FOR&&LINUX_NETFILTER
1412 LOC: Config.onoff.tproxy_uses_indirect_client
1414 Controls whether the indirect client address
1415 (see follow_x_forwarded_for) is used instead of the
1416 direct client address when spoofing the outgoing client.
1418 This has no effect on requests arriving in non-tproxy
1421 SECURITY WARNING: Usage of this option is dangerous
1422 and should not be used trivially. Correct configuration
1423 of follow_x_forwarded_for with a limited set of trusted
1424 sources is required to prevent abuse of your proxy.
1427 NAME: spoof_client_ip
1429 LOC: Config.accessList.spoof_client_ip
1431 DEFAULT_DOC: Allow spoofing on all TPROXY traffic.
1433 Control client IP address spoofing of TPROXY traffic based on
1434 defined access lists.
1436 spoof_client_ip allow|deny [!]aclname ...
1438 If there are no "spoof_client_ip" lines present, the default
1439 is to "allow" spoofing of any suitable request.
1441 Note that the cache_peer "no-tproxy" option overrides this ACL.
1443 This clause supports fast acl types.
1444 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1449 LOC: Config.accessList.http
1450 DEFAULT_IF_NONE: deny all
1451 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1453 Allowing or Denying access based on defined access lists
1455 To allow or deny a message received on an HTTP, HTTPS, or FTP port:
1456 http_access allow|deny [!]aclname ...
1458 NOTE on default values:
1460 If there are no "access" lines present, the default is to deny
1463 If none of the "access" lines cause a match, the default is the
1464 opposite of the last line in the list. If the last line was
1465 deny, the default is allow. Conversely, if the last line
1466 is allow, the default will be deny. For these reasons, it is a
1467 good idea to have an "deny all" entry at the end of your access
1468 lists to avoid potential confusion.
1470 This clause supports both fast and slow acl types.
1471 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1476 # Recommended minimum Access Permission configuration:
1478 # Deny requests to certain unsafe ports
1479 http_access deny !Safe_ports
1481 # Deny CONNECT to other than secure SSL ports
1482 http_access deny CONNECT !SSL_ports
1484 # Only allow cachemgr access from localhost
1485 http_access allow localhost manager
1486 http_access deny manager
1488 # We strongly recommend the following be uncommented to protect innocent
1489 # web applications running on the proxy server who think the only
1490 # one who can access services on "localhost" is a local user
1491 #http_access deny to_localhost
1494 # INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS
1497 # Example rule allowing access from your local networks.
1498 # Adapt localnet in the ACL section to list your (internal) IP networks
1499 # from where browsing should be allowed
1500 http_access allow localnet
1501 http_access allow localhost
1503 # And finally deny all other access to this proxy
1504 http_access deny all
1508 NAME: adapted_http_access http_access2
1510 LOC: Config.accessList.adapted_http
1512 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1514 Allowing or Denying access based on defined access lists
1516 Essentially identical to http_access, but runs after redirectors
1517 and ICAP/eCAP adaptation. Allowing access control based on their
1520 If not set then only http_access is used.
1523 NAME: http_reply_access
1525 LOC: Config.accessList.reply
1527 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1529 Allow replies to client requests. This is complementary to http_access.
1531 http_reply_access allow|deny [!] aclname ...
1533 NOTE: if there are no access lines present, the default is to allow
1536 If none of the access lines cause a match the opposite of the
1537 last line will apply. Thus it is good practice to end the rules
1538 with an "allow all" or "deny all" entry.
1540 This clause supports both fast and slow acl types.
1541 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1546 LOC: Config.accessList.icp
1548 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1550 Allowing or Denying access to the ICP port based on defined
1553 icp_access allow|deny [!]aclname ...
1555 NOTE: The default if no icp_access lines are present is to
1556 deny all traffic. This default may cause problems with peers
1559 This clause only supports fast acl types.
1560 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1562 # Allow ICP queries from local networks only
1563 #icp_access allow localnet
1564 #icp_access deny all
1570 LOC: Config.accessList.htcp
1572 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1574 Allowing or Denying access to the HTCP port based on defined
1577 htcp_access allow|deny [!]aclname ...
1579 See also htcp_clr_access for details on access control for
1580 cache purge (CLR) HTCP messages.
1582 NOTE: The default if no htcp_access lines are present is to
1583 deny all traffic. This default may cause problems with peers
1584 using the htcp option.
1586 This clause only supports fast acl types.
1587 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1589 # Allow HTCP queries from local networks only
1590 #htcp_access allow localnet
1591 #htcp_access deny all
1594 NAME: htcp_clr_access
1597 LOC: Config.accessList.htcp_clr
1599 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1601 Allowing or Denying access to purge content using HTCP based
1602 on defined access lists.
1603 See htcp_access for details on general HTCP access control.
1605 htcp_clr_access allow|deny [!]aclname ...
1607 This clause only supports fast acl types.
1608 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1610 # Allow HTCP CLR requests from trusted peers
1611 acl htcp_clr_peer src 192.0.2.2 2001:DB8::2
1612 htcp_clr_access allow htcp_clr_peer
1613 htcp_clr_access deny all
1618 LOC: Config.accessList.miss
1620 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1622 Determines whether network access is permitted when satisfying a request.
1625 to force your neighbors to use you as a sibling instead of
1628 acl localclients src 192.0.2.0/24 2001:DB8::a:0/64
1629 miss_access deny !localclients
1630 miss_access allow all
1632 This means only your local clients are allowed to fetch relayed/MISS
1633 replies from the network and all other clients can only fetch cached
1636 The default for this setting allows all clients who passed the
1637 http_access rules to relay via this proxy.
1639 This clause only supports fast acl types.
1640 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1643 NAME: ident_lookup_access
1647 DEFAULT_DOC: Unless rules exist in squid.conf, IDENT is not fetched.
1648 LOC: Ident::TheConfig.identLookup
1650 A list of ACL elements which, if matched, cause an ident
1651 (RFC 931) lookup to be performed for this request. For
1652 example, you might choose to always perform ident lookups
1653 for your main multi-user Unix boxes, but not for your Macs
1654 and PCs. By default, ident lookups are not performed for
1657 To enable ident lookups for specific client addresses, you
1658 can follow this example:
1660 acl ident_aware_hosts src 198.168.1.0/24
1661 ident_lookup_access allow ident_aware_hosts
1662 ident_lookup_access deny all
1664 Only src type ACL checks are fully supported. A srcdomain
1665 ACL might work at times, but it will not always provide
1668 This clause only supports fast acl types.
1669 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1672 NAME: reply_body_max_size
1673 COMMENT: size [acl acl...]
1676 DEFAULT_DOC: No limit is applied.
1677 LOC: Config.ReplyBodySize
1679 This option specifies the maximum size of a reply body. It can be
1680 used to prevent users from downloading very large files, such as
1681 MP3's and movies. When the reply headers are received, the
1682 reply_body_max_size lines are processed, and the first line where
1683 all (if any) listed ACLs are true is used as the maximum body size
1686 This size is checked twice. First when we get the reply headers,
1687 we check the content-length value. If the content length value exists
1688 and is larger than the allowed size, the request is denied and the
1689 user receives an error message that says "the request or reply
1690 is too large." If there is no content-length, and the reply
1691 size exceeds this limit, the client's connection is just closed
1692 and they will receive a partial reply.
1694 WARNING: downstream caches probably can not detect a partial reply
1695 if there is no content-length header, so they will cache
1696 partial responses and give them out as hits. You should NOT
1697 use this option if you have downstream caches.
1699 WARNING: A maximum size smaller than the size of squid's error messages
1700 will cause an infinite loop and crash squid. Ensure that the smallest
1701 non-zero value you use is greater that the maximum header size plus
1702 the size of your largest error page.
1704 If you set this parameter none (the default), there will be
1707 Configuration Format is:
1708 reply_body_max_size SIZE UNITS [acl ...]
1710 reply_body_max_size 10 MB
1714 NAME: on_unsupported_protocol
1715 TYPE: on_unsupported_protocol
1716 LOC: Config.accessList.on_unsupported_protocol
1718 DEFAULT_DOC: Respond with an error message to unidentifiable traffic
1720 Determines Squid behavior when encountering strange requests at the
1721 beginning of an accepted TCP connection or the beginning of a bumped
1722 CONNECT tunnel. Controlling Squid reaction to unexpected traffic is
1723 especially useful in interception environments where Squid is likely
1724 to see connections for unsupported protocols that Squid should either
1725 terminate or tunnel at TCP level.
1727 on_unsupported_protocol <action> [!]acl ...
1729 The first matching action wins. Only fast ACLs are supported.
1731 Supported actions are:
1733 tunnel: Establish a TCP connection with the intended server and
1734 blindly shovel TCP packets between the client and server.
1736 respond: Respond with an error message, using the transfer protocol
1737 for the Squid port that received the request (e.g., HTTP
1738 for connections intercepted at the http_port). This is the
1741 Squid expects the following traffic patterns:
1743 http_port: a plain HTTP request
1744 https_port: SSL/TLS handshake followed by an [encrypted] HTTP request
1745 ftp_port: a plain FTP command (no on_unsupported_protocol support yet!)
1746 CONNECT tunnel on http_port: same as https_port
1747 CONNECT tunnel on https_port: same as https_port
1749 Currently, this directive has effect on intercepted connections and
1750 bumped tunnels only. Other cases are not supported because Squid
1751 cannot know the intended destination of other traffic.
1754 # define what Squid errors indicate receiving non-HTTP traffic:
1755 acl foreignProtocol squid_error ERR_PROTOCOL_UNKNOWN ERR_TOO_BIG
1756 # define what Squid errors indicate receiving nothing:
1757 acl serverTalksFirstProtocol squid_error ERR_REQUEST_START_TIMEOUT
1758 # tunnel everything that does not look like HTTP:
1759 on_unsupported_protocol tunnel foreignProtocol
1760 # tunnel if we think the client waits for the server to talk first:
1761 on_unsupported_protocol tunnel serverTalksFirstProtocol
1762 # in all other error cases, just send an HTTP "error page" response:
1763 on_unsupported_protocol respond all
1765 See also: squid_error ACL
1770 -----------------------------------------------------------------------------
1773 NAME: http_port ascii_port
1778 Usage: port [mode] [options]
1779 hostname:port [mode] [options]
1780 1.2.3.4:port [mode] [options]
1782 The socket addresses where Squid will listen for HTTP client
1783 requests. You may specify multiple socket addresses.
1784 There are three forms: port alone, hostname with port, and
1785 IP address with port. If you specify a hostname or IP
1786 address, Squid binds the socket to that specific
1787 address. Most likely, you do not need to bind to a specific
1788 address, so you can use the port number alone.
1790 If you are running Squid in accelerator mode, you
1791 probably want to listen on port 80 also, or instead.
1793 The -a command line option may be used to specify additional
1794 port(s) where Squid listens for proxy request. Such ports will
1795 be plain proxy ports with no options.
1797 You may specify multiple socket addresses on multiple lines.
1801 intercept Support for IP-Layer NAT interception delivering
1802 traffic to this Squid port.
1803 NP: disables authentication on the port.
1805 tproxy Support Linux TPROXY (or BSD divert-to) with spoofing
1806 of outgoing connections using the client IP address.
1807 NP: disables authentication on the port.
1809 accel Accelerator / reverse proxy mode
1811 ssl-bump For each CONNECT request allowed by ssl_bump ACLs,
1812 establish secure connection with the client and with
1813 the server, decrypt HTTPS messages as they pass through
1814 Squid, and treat them as unencrypted HTTP messages,
1815 becoming the man-in-the-middle.
1817 The ssl_bump option is required to fully enable
1818 bumping of CONNECT requests.
1820 Omitting the mode flag causes default forward proxy mode to be used.
1823 Accelerator Mode Options:
1825 defaultsite=domainname
1826 What to use for the Host: header if it is not present
1827 in a request. Determines what site (not origin server)
1828 accelerators should consider the default.
1830 no-vhost Disable using HTTP/1.1 Host header for virtual domain support.
1832 protocol= Protocol to reconstruct accelerated and intercepted
1833 requests with. Defaults to HTTP/1.1 for http_port and
1834 HTTPS/1.1 for https_port.
1835 When an unsupported value is configured Squid will
1836 produce a FATAL error.
1837 Values: HTTP or HTTP/1.1, HTTPS or HTTPS/1.1
1839 vport Virtual host port support. Using the http_port number
1840 instead of the port passed on Host: headers.
1842 vport=NN Virtual host port support. Using the specified port
1843 number instead of the port passed on Host: headers.
1846 Act as if this Squid is the origin server.
1847 This currently means generate new Date: and Expires:
1848 headers on HIT instead of adding Age:.
1850 ignore-cc Ignore request Cache-Control headers.
1852 WARNING: This option violates HTTP specifications if
1853 used in non-accelerator setups.
1855 allow-direct Allow direct forwarding in accelerator mode. Normally
1856 accelerated requests are denied direct forwarding as if
1857 never_direct was used.
1859 WARNING: this option opens accelerator mode to security
1860 vulnerabilities usually only affecting in interception
1861 mode. Make sure to protect forwarding with suitable
1862 http_access rules when using this.
1865 SSL Bump Mode Options:
1866 In addition to these options ssl-bump requires TLS/SSL options.
1868 generate-host-certificates[=<on|off>]
1869 Dynamically create SSL server certificates for the
1870 destination hosts of bumped CONNECT requests.When
1871 enabled, the cert and key options are used to sign
1872 generated certificates. Otherwise generated
1873 certificate will be selfsigned.
1874 If there is a CA certificate lifetime of the generated
1875 certificate equals lifetime of the CA certificate. If
1876 generated certificate is selfsigned lifetime is three
1878 This option is enabled by default when ssl-bump is used.
1879 See the ssl-bump option above for more information.
1881 dynamic_cert_mem_cache_size=SIZE
1882 Approximate total RAM size spent on cached generated
1883 certificates. If set to zero, caching is disabled. The
1884 default value is 4MB.
1888 cert= Path to SSL certificate (PEM format).
1890 key= Path to SSL private key file (PEM format)
1891 if not specified, the certificate file is
1892 assumed to be a combined certificate and
1895 cipher= Colon separated list of supported ciphers.
1896 NOTE: some ciphers such as EDH ciphers depend on
1897 additional settings. If those settings are
1898 omitted the ciphers may be silently ignored
1899 by the OpenSSL library.
1901 options= Various SSL implementation options. The most important
1904 NO_SSLv3 Disallow the use of SSLv3
1906 NO_TLSv1 Disallow the use of TLSv1.0
1908 NO_TLSv1_1 Disallow the use of TLSv1.1
1910 NO_TLSv1_2 Disallow the use of TLSv1.2
1913 Always create a new key when using
1914 temporary/ephemeral DH key exchanges
1917 Enable ephemeral ECDH key exchange.
1918 The adopted curve should be specified
1919 using the tls-dh option.
1922 Disable use of RFC5077 session tickets.
1923 Some servers may have problems
1924 understanding the TLS extension due
1925 to ambiguous specification in RFC4507.
1927 ALL Enable various bug workarounds
1928 suggested as "harmless" by OpenSSL
1929 Be warned that this reduces SSL/TLS
1930 strength to some attacks.
1932 See the OpenSSL SSL_CTX_set_options documentation for a
1935 clientca= File containing the list of CAs to use when
1936 requesting a client certificate.
1938 tls-cafile= PEM file containing CA certificates to use when verifying
1939 client certificates. If not configured clientca will be
1940 used. May be repeated to load multiple files.
1942 capath= Directory containing additional CA certificates
1943 and CRL lists to use when verifying client certificates.
1944 Requires OpenSSL or LibreSSL.
1946 crlfile= File of additional CRL lists to use when verifying
1947 the client certificate, in addition to CRLs stored in
1948 the capath. Implies VERIFY_CRL flag below.
1951 File containing DH parameters for temporary/ephemeral DH key
1952 exchanges, optionally prefixed by a curve for ephemeral ECDH
1954 See OpenSSL documentation for details on how to create the
1955 DH parameter file. Supported curves for ECDH can be listed
1956 using the "openssl ecparam -list_curves" command.
1957 WARNING: EDH and EECDH ciphers will be silently disabled if
1958 this option is not set.
1960 sslflags= Various flags modifying the use of SSL:
1962 Don't request client certificates
1963 immediately, but wait until acl processing
1964 requires a certificate (not yet implemented).
1966 Don't allow for session reuse. Each connection
1967 will result in a new SSL session.
1969 Verify CRL lists when accepting client
1972 Verify CRL lists for all certificates in the
1973 client certificate chain.
1976 Do not use the system default Trusted CA.
1978 sslcontext= SSL session ID context identifier.
1982 connection-auth[=on|off]
1983 use connection-auth=off to tell Squid to prevent
1984 forwarding Microsoft connection oriented authentication
1985 (NTLM, Negotiate and Kerberos)
1987 disable-pmtu-discovery=
1988 Control Path-MTU discovery usage:
1989 off lets OS decide on what to do (default).
1990 transparent disable PMTU discovery when transparent
1992 always disable always PMTU discovery.
1994 In many setups of transparently intercepting proxies
1995 Path-MTU discovery can not work on traffic towards the
1996 clients. This is the case when the intercepting device
1997 does not fully track connections and fails to forward
1998 ICMP must fragment messages to the cache server. If you
1999 have such setup and experience that certain clients
2000 sporadically hang or never complete requests set
2001 disable-pmtu-discovery option to 'transparent'.
2003 name= Specifies a internal name for the port. Defaults to
2004 the port specification (port or addr:port)
2006 tcpkeepalive[=idle,interval,timeout]
2007 Enable TCP keepalive probes of idle connections.
2008 In seconds; idle is the initial time before TCP starts
2009 probing the connection, interval how often to probe, and
2010 timeout the time before giving up.
2012 require-proxy-header
2013 Require PROXY protocol version 1 or 2 connections.
2014 The proxy_protocol_access is required to whitelist
2015 downstream proxies which can be trusted.
2017 If you run Squid on a dual-homed machine with an internal
2018 and an external interface we recommend you to specify the
2019 internal address:port in http_port. This way Squid will only be
2020 visible on the internal address.
2024 # Squid normally listens to port 3128
2025 http_port @DEFAULT_HTTP_PORT@
2035 Usage: [ip:]port [mode] cert=certificate.pem [options]
2037 The socket address where Squid will listen for client requests made
2038 over TLS or SSL connections. Commonly referred to as HTTPS.
2040 This is most useful for situations where you are running squid in
2041 accelerator mode and you want to do the TLS work at the accelerator level.
2043 You may specify multiple socket addresses on multiple lines,
2044 each with their own certificate and/or options.
2046 The TLS cert= option is mandatory on HTTPS ports.
2048 See http_port for a list of modes and options.
2056 Enables Native FTP proxy by specifying the socket address where Squid
2057 listens for FTP client requests. See http_port directive for various
2058 ways to specify the listening address and mode.
2060 Usage: ftp_port address [mode] [options]
2062 WARNING: This is a new, experimental, complex feature that has seen
2063 limited production exposure. Some Squid modules (e.g., caching) do not
2064 currently work with native FTP proxying, and many features have not
2065 even been tested for compatibility. Test well before deploying!
2067 Native FTP proxying differs substantially from proxying HTTP requests
2068 with ftp:// URIs because Squid works as an FTP server and receives
2069 actual FTP commands (rather than HTTP requests with FTP URLs).
2071 Native FTP commands accepted at ftp_port are internally converted or
2072 wrapped into HTTP-like messages. The same happens to Native FTP
2073 responses received from FTP origin servers. Those HTTP-like messages
2074 are shoveled through regular access control and adaptation layers
2075 between the FTP client and the FTP origin server. This allows Squid to
2076 examine, adapt, block, and log FTP exchanges. Squid reuses most HTTP
2077 mechanisms when shoveling wrapped FTP messages. For example,
2078 http_access and adaptation_access directives are used.
2082 intercept Same as http_port intercept. The FTP origin address is
2083 determined based on the intended destination of the
2084 intercepted connection.
2086 tproxy Support Linux TPROXY for spoofing outgoing
2087 connections using the client IP address.
2088 NP: disables authentication and maybe IPv6 on the port.
2090 By default (i.e., without an explicit mode option), Squid extracts the
2091 FTP origin address from the login@origin parameter of the FTP USER
2092 command. Many popular FTP clients support such native FTP proxying.
2096 name=token Specifies an internal name for the port. Defaults to
2097 the port address. Usable with myportname ACL.
2100 Enables tracking of FTP directories by injecting extra
2101 PWD commands and adjusting Request-URI (in wrapping
2102 HTTP requests) to reflect the current FTP server
2103 directory. Tracking is disabled by default.
2105 protocol=FTP Protocol to reconstruct accelerated and intercepted
2106 requests with. Defaults to FTP. No other accepted
2107 values have been tested with. An unsupported value
2108 results in a FATAL error. Accepted values are FTP,
2109 HTTP (or HTTP/1.1), and HTTPS (or HTTPS/1.1).
2111 Other http_port modes and options that are not specific to HTTP and
2112 HTTPS may also work.
2115 NAME: tcp_outgoing_tos tcp_outgoing_ds tcp_outgoing_dscp
2118 LOC: Ip::Qos::TheConfig.tosToServer
2120 Allows you to select a TOS/Diffserv value for packets outgoing
2121 on the server side, based on an ACL.
2123 tcp_outgoing_tos ds-field [!]aclname ...
2125 Example where normal_service_net uses the TOS value 0x00
2126 and good_service_net uses 0x20
2128 acl normal_service_net src 10.0.0.0/24
2129 acl good_service_net src 10.0.1.0/24
2130 tcp_outgoing_tos 0x00 normal_service_net
2131 tcp_outgoing_tos 0x20 good_service_net
2133 TOS/DSCP values really only have local significance - so you should
2134 know what you're specifying. For more information, see RFC2474,
2135 RFC2475, and RFC3260.
2137 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
2138 "default" to use whatever default your host has.
2139 Note that only multiples of 4 are usable as the two rightmost bits have
2140 been redefined for use by ECN (RFC 3168 section 23.1).
2141 The squid parser will enforce this by masking away the ECN bits.
2143 Processing proceeds in the order specified, and stops at first fully
2146 Only fast ACLs are supported.
2149 NAME: clientside_tos
2152 LOC: Ip::Qos::TheConfig.tosToClient
2154 Allows you to select a TOS/DSCP value for packets being transmitted
2155 on the client-side, based on an ACL.
2157 clientside_tos ds-field [!]aclname ...
2159 Example where normal_service_net uses the TOS value 0x00
2160 and good_service_net uses 0x20
2162 acl normal_service_net src 10.0.0.0/24
2163 acl good_service_net src 10.0.1.0/24
2164 clientside_tos 0x00 normal_service_net
2165 clientside_tos 0x20 good_service_net
2167 Note: This feature is incompatible with qos_flows. Any TOS values set here
2168 will be overwritten by TOS values in qos_flows.
2170 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
2171 "default" to use whatever default your host has.
2172 Note that only multiples of 4 are usable as the two rightmost bits have
2173 been redefined for use by ECN (RFC 3168 section 23.1).
2174 The squid parser will enforce this by masking away the ECN bits.
2178 NAME: tcp_outgoing_mark
2180 IFDEF: SO_MARK&&USE_LIBCAP
2182 LOC: Ip::Qos::TheConfig.nfmarkToServer
2184 Allows you to apply a Netfilter mark value to outgoing packets
2185 on the server side, based on an ACL.
2187 tcp_outgoing_mark mark-value [!]aclname ...
2189 Example where normal_service_net uses the mark value 0x00
2190 and good_service_net uses 0x20
2192 acl normal_service_net src 10.0.0.0/24
2193 acl good_service_net src 10.0.1.0/24
2194 tcp_outgoing_mark 0x00 normal_service_net
2195 tcp_outgoing_mark 0x20 good_service_net
2197 Only fast ACLs are supported.
2200 NAME: clientside_mark
2202 IFDEF: SO_MARK&&USE_LIBCAP
2204 LOC: Ip::Qos::TheConfig.nfmarkToClient
2206 Allows you to apply a Netfilter mark value to packets being transmitted
2207 on the client-side, based on an ACL.
2209 clientside_mark mark-value [!]aclname ...
2211 Example where normal_service_net uses the mark value 0x00
2212 and good_service_net uses 0x20
2214 acl normal_service_net src 10.0.0.0/24
2215 acl good_service_net src 10.0.1.0/24
2216 clientside_mark 0x00 normal_service_net
2217 clientside_mark 0x20 good_service_net
2219 Note: This feature is incompatible with qos_flows. Any mark values set here
2220 will be overwritten by mark values in qos_flows.
2227 LOC: Ip::Qos::TheConfig
2229 Allows you to select a TOS/DSCP value to mark outgoing
2230 connections to the client, based on where the reply was sourced.
2231 For platforms using netfilter, allows you to set a netfilter mark
2232 value instead of, or in addition to, a TOS value.
2234 By default this functionality is disabled. To enable it with the default
2235 settings simply use "qos_flows mark" or "qos_flows tos". Default
2236 settings will result in the netfilter mark or TOS value being copied
2237 from the upstream connection to the client. Note that it is the connection
2238 CONNMARK value not the packet MARK value that is copied.
2240 It is not currently possible to copy the mark or TOS value from the
2241 client to the upstream connection request.
2243 TOS values really only have local significance - so you should
2244 know what you're specifying. For more information, see RFC2474,
2245 RFC2475, and RFC3260.
2247 The TOS/DSCP byte must be exactly that - a octet value 0 - 255.
2248 Note that only multiples of 4 are usable as the two rightmost bits have
2249 been redefined for use by ECN (RFC 3168 section 23.1).
2250 The squid parser will enforce this by masking away the ECN bits.
2252 Mark values can be any unsigned 32-bit integer value.
2254 This setting is configured by setting the following values:
2256 tos|mark Whether to set TOS or netfilter mark values
2258 local-hit=0xFF Value to mark local cache hits.
2260 sibling-hit=0xFF Value to mark hits from sibling peers.
2262 parent-hit=0xFF Value to mark hits from parent peers.
2264 miss=0xFF[/mask] Value to mark cache misses. Takes precedence
2265 over the preserve-miss feature (see below), unless
2266 mask is specified, in which case only the bits
2267 specified in the mask are written.
2269 The TOS variant of the following features are only possible on Linux
2270 and require your kernel to be patched with the TOS preserving ZPH
2271 patch, available from http://zph.bratcheda.org
2272 No patch is needed to preserve the netfilter mark, which will work
2273 with all variants of netfilter.
2275 disable-preserve-miss
2276 This option disables the preservation of the TOS or netfilter
2277 mark. By default, the existing TOS or netfilter mark value of
2278 the response coming from the remote server will be retained
2279 and masked with miss-mark.
2280 NOTE: in the case of a netfilter mark, the mark must be set on
2281 the connection (using the CONNMARK target) not on the packet
2285 Allows you to mask certain bits in the TOS or mark value
2286 received from the remote server, before copying the value to
2287 the TOS sent towards clients.
2288 Default for tos: 0xFF (TOS from server is not changed).
2289 Default for mark: 0xFFFFFFFF (mark from server is not changed).
2291 All of these features require the --enable-zph-qos compilation flag
2292 (enabled by default). Netfilter marking also requires the
2293 libnetfilter_conntrack libraries (--with-netfilter-conntrack) and
2294 libcap 2.09+ (--with-libcap).
2298 NAME: tcp_outgoing_address
2301 DEFAULT_DOC: Address selection is performed by the operating system.
2302 LOC: Config.accessList.outgoing_address
2304 Allows you to map requests to different outgoing IP addresses
2305 based on the username or source address of the user making
2308 tcp_outgoing_address ipaddr [[!]aclname] ...
2311 Forwarding clients with dedicated IPs for certain subnets.
2313 acl normal_service_net src 10.0.0.0/24
2314 acl good_service_net src 10.0.2.0/24
2316 tcp_outgoing_address 2001:db8::c001 good_service_net
2317 tcp_outgoing_address 10.1.0.2 good_service_net
2319 tcp_outgoing_address 2001:db8::beef normal_service_net
2320 tcp_outgoing_address 10.1.0.1 normal_service_net
2322 tcp_outgoing_address 2001:db8::1
2323 tcp_outgoing_address 10.1.0.3
2325 Processing proceeds in the order specified, and stops at first fully
2328 Squid will add an implicit IP version test to each line.
2329 Requests going to IPv4 websites will use the outgoing 10.1.0.* addresses.
2330 Requests going to IPv6 websites will use the outgoing 2001:db8:* addresses.
2333 NOTE: The use of this directive using client dependent ACLs is
2334 incompatible with the use of server side persistent connections. To
2335 ensure correct results it is best to set server_persistent_connections
2336 to off when using this directive in such configurations.
2338 NOTE: The use of this directive to set a local IP on outgoing TCP links
2339 is incompatible with using TPROXY to set client IP out outbound TCP links.
2340 When needing to contact peers use the no-tproxy cache_peer option and the
2341 client_dst_passthru directive re-enable normal forwarding such as this.
2345 NAME: host_verify_strict
2348 LOC: Config.onoff.hostStrictVerify
2350 Regardless of this option setting, when dealing with intercepted
2351 traffic, Squid always verifies that the destination IP address matches
2352 the Host header domain or IP (called 'authority form URL').
2354 This enforcement is performed to satisfy a MUST-level requirement in
2355 RFC 2616 section 14.23: "The Host field value MUST represent the naming
2356 authority of the origin server or gateway given by the original URL".
2359 Squid always responds with an HTTP 409 (Conflict) error
2360 page and logs a security warning if there is no match.
2362 Squid verifies that the destination IP address matches
2363 the Host header for forward-proxy and reverse-proxy traffic
2364 as well. For those traffic types, Squid also enables the
2365 following checks, comparing the corresponding Host header
2366 and Request-URI components:
2368 * The host names (domain or IP) must be identical,
2369 but valueless or missing Host header disables all checks.
2370 For the two host names to match, both must be either IP
2373 * Port numbers must be identical, but if a port is missing
2374 the scheme-default port is assumed.
2377 When set to OFF (the default):
2378 Squid allows suspicious requests to continue but logs a
2379 security warning and blocks caching of the response.
2381 * Forward-proxy traffic is not checked at all.
2383 * Reverse-proxy traffic is not checked at all.
2385 * Intercepted traffic which passes verification is handled
2386 according to client_dst_passthru.
2388 * Intercepted requests which fail verification are sent
2389 to the client original destination instead of DIRECT.
2390 This overrides 'client_dst_passthru off'.
2392 For now suspicious intercepted CONNECT requests are always
2393 responded to with an HTTP 409 (Conflict) error page.
2398 As described in CVE-2009-0801 when the Host: header alone is used
2399 to determine the destination of a request it becomes trivial for
2400 malicious scripts on remote websites to bypass browser same-origin
2401 security policy and sandboxing protections.
2403 The cause of this is that such applets are allowed to perform their
2404 own HTTP stack, in which case the same-origin policy of the browser
2405 sandbox only verifies that the applet tries to contact the same IP
2406 as from where it was loaded at the IP level. The Host: header may
2407 be different from the connected IP and approved origin.
2411 NAME: client_dst_passthru
2414 LOC: Config.onoff.client_dst_passthru
2416 With NAT or TPROXY intercepted traffic Squid may pass the request
2417 directly to the original client destination IP or seek a faster
2418 source using the HTTP Host header.
2420 Using Host to locate alternative servers can provide faster
2421 connectivity with a range of failure recovery options.
2422 But can also lead to connectivity trouble when the client and
2423 server are attempting stateful interactions unaware of the proxy.
2425 This option (on by default) prevents alternative DNS entries being
2426 located to send intercepted traffic DIRECT to an origin server.
2427 The clients original destination IP and port will be used instead.
2429 Regardless of this option setting, when dealing with intercepted
2430 traffic Squid will verify the Host: header and any traffic which
2431 fails Host verification will be treated as if this option were ON.
2433 see host_verify_strict for details on the verification process.
2438 -----------------------------------------------------------------------------
2441 NAME: tls_outgoing_options
2442 IFDEF: USE_GNUTLS||USE_OPENSSL
2443 TYPE: securePeerOptions
2444 DEFAULT: min-version=1.0
2445 LOC: Security::ProxyOutgoingConfig
2447 disable Do not support https:// URLs.
2449 cert=/path/to/client/certificate
2450 A client TLS certificate to use when connecting.
2452 key=/path/to/client/private_key
2453 The private TLS key corresponding to the cert= above.
2454 If key= is not specified cert= is assumed to reference
2455 a PEM file containing both the certificate and the key.
2457 cipher=... The list of valid TLS ciphers to use.
2460 The minimum TLS protocol version to permit.
2461 To control SSLv3 use the options= parameter.
2462 Supported Values: 1.0 (default), 1.1, 1.2
2464 options=... Specify various TLS/SSL implementation options:
2466 NO_SSLv3 Disallow the use of SSLv3
2468 NO_TLSv1 Disallow the use of TLSv1.0
2470 NO_TLSv1_1 Disallow the use of TLSv1.1
2472 NO_TLSv1_2 Disallow the use of TLSv1.2
2475 Always create a new key when using
2476 temporary/ephemeral DH key exchanges
2479 Disable use of RFC5077 session tickets.
2480 Some servers may have problems
2481 understanding the TLS extension due
2482 to ambiguous specification in RFC4507.
2484 ALL Enable various bug workarounds
2485 suggested as "harmless" by OpenSSL
2486 Be warned that this reduces SSL/TLS
2487 strength to some attacks.
2489 See the OpenSSL SSL_CTX_set_options documentation for a
2492 cafile= PEM file containing CA certificates to use when verifying
2493 the peer certificate. May be repeated to load multiple files.
2495 capath= A directory containing additional CA certificates to
2496 use when verifying the peer certificate.
2497 Requires OpenSSL or LibreSSL.
2499 crlfile=... A certificate revocation list file to use when
2500 verifying the peer certificate.
2502 flags=... Specify various flags modifying the TLS implementation:
2505 Accept certificates even if they fail to
2508 Don't verify the peer certificate
2509 matches the server name
2511 no-default-ca Do not use the system default Trusted CA.
2513 domain= The peer name as advertised in its certificate.
2514 Used for verifying the correctness of the received peer
2515 certificate. If not specified the peer hostname will be
2521 -----------------------------------------------------------------------------
2524 NAME: ssl_unclean_shutdown
2528 LOC: Config.SSL.unclean_shutdown
2530 Some browsers (especially MSIE) bugs out on SSL shutdown
2537 LOC: Config.SSL.ssl_engine
2540 The OpenSSL engine to use. You will need to set this if you
2541 would like to use hardware SSL acceleration for example.
2544 NAME: sslproxy_session_ttl
2547 LOC: Config.SSL.session_ttl
2550 Sets the timeout value for SSL sessions
2553 NAME: sslproxy_session_cache_size
2556 LOC: Config.SSL.sessionCacheSize
2559 Sets the cache size to use for ssl session
2562 NAME: sslproxy_cert_sign_hash
2565 LOC: Config.SSL.certSignHash
2568 Sets the hashing algorithm to use when signing generated certificates.
2569 Valid algorithm names depend on the OpenSSL library used. The following
2570 names are usually available: sha1, sha256, sha512, and md5. Please see
2571 your OpenSSL library manual for the available hashes. By default, Squids
2572 that support this option use sha256 hashes.
2574 Squid does not forcefully purge cached certificates that were generated
2575 with an algorithm other than the currently configured one. They remain
2576 in the cache, subject to the regular cache eviction policy, and become
2577 useful if the algorithm changes again.
2582 TYPE: sslproxy_ssl_bump
2583 LOC: Config.accessList.ssl_bump
2584 DEFAULT_DOC: Become a TCP tunnel without decrypting proxied traffic.
2587 This option is consulted when a CONNECT request is received on
2588 an http_port (or a new connection is intercepted at an
2589 https_port), provided that port was configured with an ssl-bump
2590 flag. The subsequent data on the connection is either treated as
2591 HTTPS and decrypted OR tunneled at TCP level without decryption,
2592 depending on the first matching bumping "action".
2594 ssl_bump <action> [!]acl ...
2596 The following bumping actions are currently supported:
2599 Become a TCP tunnel without decrypting proxied traffic.
2600 This is the default action.
2603 Establish a secure connection with the server and, using a
2604 mimicked server certificate, with the client.
2607 Receive client (step SslBump1) or server (step SslBump2)
2608 certificate while preserving the possibility of splicing the
2609 connection. Peeking at the server certificate (during step 2)
2610 usually precludes bumping of the connection at step 3.
2613 Receive client (step SslBump1) or server (step SslBump2)
2614 certificate while preserving the possibility of bumping the
2615 connection. Staring at the server certificate (during step 2)
2616 usually precludes splicing of the connection at step 3.
2619 Close client and server connections.
2621 Backward compatibility actions available at step SslBump1:
2624 Bump the connection. Establish a secure connection with the
2625 client first, then connect to the server. This old mode does
2626 not allow Squid to mimic server SSL certificate and does not
2627 work with intercepted SSL connections.
2630 Bump the connection. Establish a secure connection with the
2631 server first, then establish a secure connection with the
2632 client, using a mimicked server certificate. Works with both
2633 CONNECT requests and intercepted SSL connections, but does
2634 not allow to make decisions based on SSL handshake info.
2637 Decide whether to bump or splice the connection based on
2638 client-to-squid and server-to-squid SSL hello messages.
2642 Same as the "splice" action.
2644 All ssl_bump rules are evaluated at each of the supported bumping
2645 steps. Rules with actions that are impossible at the current step are
2646 ignored. The first matching ssl_bump action wins and is applied at the
2647 end of the current step. If no rules match, the splice action is used.
2648 See the at_step ACL for a list of the supported SslBump steps.
2650 This clause supports both fast and slow acl types.
2651 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2653 See also: http_port ssl-bump, https_port ssl-bump, and acl at_step.
2656 # Example: Bump all requests except those originating from
2657 # localhost or those going to example.com.
2659 acl broken_sites dstdomain .example.com
2660 ssl_bump splice localhost
2661 ssl_bump splice broken_sites
2665 NAME: sslproxy_cert_error
2668 DEFAULT_DOC: Server certificate errors terminate the transaction.
2669 LOC: Config.ssl_client.cert_error
2672 Use this ACL to bypass server certificate validation errors.
2674 For example, the following lines will bypass all validation errors
2675 when talking to servers for example.com. All other
2676 validation errors will result in ERR_SECURE_CONNECT_FAIL error.
2678 acl BrokenButTrustedServers dstdomain example.com
2679 sslproxy_cert_error allow BrokenButTrustedServers
2680 sslproxy_cert_error deny all
2682 This clause only supports fast acl types.
2683 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2684 Using slow acl types may result in server crashes
2686 Without this option, all server certificate validation errors
2687 terminate the transaction to protect Squid and the client.
2689 SQUID_X509_V_ERR_INFINITE_VALIDATION error cannot be bypassed
2690 but should not happen unless your OpenSSL library is buggy.
2693 Bypassing validation errors is dangerous because an
2694 error usually implies that the server cannot be trusted
2695 and the connection may be insecure.
2697 See also: sslproxy_flags and DONT_VERIFY_PEER.
2700 NAME: sslproxy_cert_sign
2703 POSTSCRIPTUM: signUntrusted ssl::certUntrusted
2704 POSTSCRIPTUM: signSelf ssl::certSelfSigned
2705 POSTSCRIPTUM: signTrusted all
2706 TYPE: sslproxy_cert_sign
2707 LOC: Config.ssl_client.cert_sign
2710 sslproxy_cert_sign <signing algorithm> acl ...
2712 The following certificate signing algorithms are supported:
2715 Sign using the configured CA certificate which is usually
2716 placed in and trusted by end-user browsers. This is the
2717 default for trusted origin server certificates.
2720 Sign to guarantee an X509_V_ERR_CERT_UNTRUSTED browser error.
2721 This is the default for untrusted origin server certificates
2722 that are not self-signed (see ssl::certUntrusted).
2725 Sign using a self-signed certificate with the right CN to
2726 generate a X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT error in the
2727 browser. This is the default for self-signed origin server
2728 certificates (see ssl::certSelfSigned).
2730 This clause only supports fast acl types.
2732 When sslproxy_cert_sign acl(s) match, Squid uses the corresponding
2733 signing algorithm to generate the certificate and ignores all
2734 subsequent sslproxy_cert_sign options (the first match wins). If no
2735 acl(s) match, the default signing algorithm is determined by errors
2736 detected when obtaining and validating the origin server certificate.
2738 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2739 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2740 CONNECT request that carries a domain name. In all other cases (CONNECT
2741 to an IP address or an intercepted SSL connection), Squid cannot detect
2742 the domain mismatch at certificate generation time when
2743 bump-server-first is used.
2746 NAME: sslproxy_cert_adapt
2749 TYPE: sslproxy_cert_adapt
2750 LOC: Config.ssl_client.cert_adapt
2753 sslproxy_cert_adapt <adaptation algorithm> acl ...
2755 The following certificate adaptation algorithms are supported:
2758 Sets the "Not After" property to the "Not After" property of
2759 the CA certificate used to sign generated certificates.
2762 Sets the "Not Before" property to the "Not Before" property of
2763 the CA certificate used to sign generated certificates.
2765 setCommonName or setCommonName{CN}
2766 Sets Subject.CN property to the host name specified as a
2767 CN parameter or, if no explicit CN parameter was specified,
2768 extracted from the CONNECT request. It is a misconfiguration
2769 to use setCommonName without an explicit parameter for
2770 intercepted or tproxied SSL connections.
2772 This clause only supports fast acl types.
2774 Squid first groups sslproxy_cert_adapt options by adaptation algorithm.
2775 Within a group, when sslproxy_cert_adapt acl(s) match, Squid uses the
2776 corresponding adaptation algorithm to generate the certificate and
2777 ignores all subsequent sslproxy_cert_adapt options in that algorithm's
2778 group (i.e., the first match wins within each algorithm group). If no
2779 acl(s) match, the default mimicking action takes place.
2781 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2782 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2783 CONNECT request that carries a domain name. In all other cases (CONNECT
2784 to an IP address or an intercepted SSL connection), Squid cannot detect
2785 the domain mismatch at certificate generation time when
2786 bump-server-first is used.
2789 NAME: sslpassword_program
2792 LOC: Config.Program.ssl_password
2795 Specify a program used for entering SSL key passphrases
2796 when using encrypted SSL certificate keys. If not specified
2797 keys must either be unencrypted, or Squid started with the -N
2798 option to allow it to query interactively for the passphrase.
2800 The key file name is given as argument to the program allowing
2801 selection of the right password if you have multiple encrypted
2806 OPTIONS RELATING TO EXTERNAL SSL_CRTD
2807 -----------------------------------------------------------------------------
2810 NAME: sslcrtd_program
2813 DEFAULT: @DEFAULT_SSL_CRTD@ -s @DEFAULT_SSL_DB_DIR@ -M 4MB
2814 LOC: Ssl::TheConfig.ssl_crtd
2816 Specify the location and options of the executable for ssl_crtd process.
2817 @DEFAULT_SSL_CRTD@ program requires -s and -M parameters
2818 For more information use:
2819 @DEFAULT_SSL_CRTD@ -h
2822 NAME: sslcrtd_children
2823 TYPE: HelperChildConfig
2825 DEFAULT: 32 startup=5 idle=1
2826 LOC: Ssl::TheConfig.ssl_crtdChildren
2828 The maximum number of processes spawn to service ssl server.
2829 The maximum this may be safely set to is 32.
2831 The startup= and idle= options allow some measure of skew in your
2836 Sets the minimum number of processes to spawn when Squid
2837 starts or reconfigures. When set to zero the first request will
2838 cause spawning of the first child process to handle it.
2840 Starting too few children temporary slows Squid under load while it
2841 tries to spawn enough additional processes to cope with traffic.
2845 Sets a minimum of how many processes Squid is to try and keep available
2846 at all times. When traffic begins to rise above what the existing
2847 processes can handle this many more will be spawned up to the maximum
2848 configured. A minimum setting of 1 is required.
2852 Sets the maximum number of queued requests.
2853 If the queued requests exceed queue size for more than 3 minutes
2854 squid aborts its operation.
2855 The default value is set to 2*numberofchildren.
2857 You must have at least one ssl_crtd process.
2860 NAME: sslcrtvalidator_program
2864 LOC: Ssl::TheConfig.ssl_crt_validator
2866 Specify the location and options of the executable for ssl_crt_validator
2869 Usage: sslcrtvalidator_program [ttl=n] [cache=n] path ...
2872 ttl=n TTL in seconds for cached results. The default is 60 secs
2873 cache=n limit the result cache size. The default value is 2048
2876 NAME: sslcrtvalidator_children
2877 TYPE: HelperChildConfig
2879 DEFAULT: 32 startup=5 idle=1 concurrency=1
2880 LOC: Ssl::TheConfig.ssl_crt_validator_Children
2882 The maximum number of processes spawn to service SSL server.
2883 The maximum this may be safely set to is 32.
2885 The startup= and idle= options allow some measure of skew in your
2890 Sets the minimum number of processes to spawn when Squid
2891 starts or reconfigures. When set to zero the first request will
2892 cause spawning of the first child process to handle it.
2894 Starting too few children temporary slows Squid under load while it
2895 tries to spawn enough additional processes to cope with traffic.
2899 Sets a minimum of how many processes Squid is to try and keep available
2900 at all times. When traffic begins to rise above what the existing
2901 processes can handle this many more will be spawned up to the maximum
2902 configured. A minimum setting of 1 is required.
2906 The number of requests each certificate validator helper can handle in
2907 parallel. A value of 0 indicates the certficate validator does not
2908 support concurrency. Defaults to 1.
2910 When this directive is set to a value >= 1 then the protocol
2911 used to communicate with the helper is modified to include
2912 a request ID in front of the request/response. The request
2913 ID from the request must be echoed back with the response
2918 Sets the maximum number of queued requests.
2919 If the queued requests exceed queue size for more than 3 minutes
2920 squid aborts its operation.
2921 The default value is set to 2*numberofchildren.
2923 You must have at least one ssl_crt_validator process.
2927 OPTIONS WHICH AFFECT THE NEIGHBOR SELECTION ALGORITHM
2928 -----------------------------------------------------------------------------
2936 To specify other caches in a hierarchy, use the format:
2938 cache_peer hostname type http-port icp-port [options]
2943 # hostname type port port options
2944 # -------------------- -------- ----- ----- -----------
2945 cache_peer parent.foo.net parent 3128 3130 default
2946 cache_peer sib1.foo.net sibling 3128 3130 proxy-only
2947 cache_peer sib2.foo.net sibling 3128 3130 proxy-only
2948 cache_peer example.com parent 80 0 default
2949 cache_peer cdn.example.com sibling 3128 0
2951 type: either 'parent', 'sibling', or 'multicast'.
2953 proxy-port: The port number where the peer accept HTTP requests.
2954 For other Squid proxies this is usually 3128
2955 For web servers this is usually 80
2957 icp-port: Used for querying neighbor caches about objects.
2958 Set to 0 if the peer does not support ICP or HTCP.
2959 See ICP and HTCP options below for additional details.
2962 ==== ICP OPTIONS ====
2964 You MUST also set icp_port and icp_access explicitly when using these options.
2965 The defaults will prevent peer traffic using ICP.
2968 no-query Disable ICP queries to this neighbor.
2971 Indicates the named peer is a member of a multicast group.
2972 ICP queries will not be sent directly to the peer, but ICP
2973 replies will be accepted from it.
2975 closest-only Indicates that, for ICP_OP_MISS replies, we'll only forward
2976 CLOSEST_PARENT_MISSes and never FIRST_PARENT_MISSes.
2979 To only send ICP queries to this neighbor infrequently.
2980 This is used to keep the neighbor round trip time updated
2981 and is usually used in conjunction with weighted-round-robin.
2984 ==== HTCP OPTIONS ====
2986 You MUST also set htcp_port and htcp_access explicitly when using these options.
2987 The defaults will prevent peer traffic using HTCP.
2990 htcp Send HTCP, instead of ICP, queries to the neighbor.
2991 You probably also want to set the "icp-port" to 4827
2992 instead of 3130. This directive accepts a comma separated
2993 list of options described below.
2995 htcp=oldsquid Send HTCP to old Squid versions (2.5 or earlier).
2997 htcp=no-clr Send HTCP to the neighbor but without
2998 sending any CLR requests. This cannot be used with
3001 htcp=only-clr Send HTCP to the neighbor but ONLY CLR requests.
3002 This cannot be used with no-clr.
3005 Send HTCP to the neighbor including CLRs but only when
3006 they do not result from PURGE requests.
3009 Forward any HTCP CLR requests this proxy receives to the peer.
3012 ==== PEER SELECTION METHODS ====
3014 The default peer selection method is ICP, with the first responding peer
3015 being used as source. These options can be used for better load balancing.
3018 default This is a parent cache which can be used as a "last-resort"
3019 if a peer cannot be located by any of the peer-selection methods.
3020 If specified more than once, only the first is used.
3022 round-robin Load-Balance parents which should be used in a round-robin
3023 fashion in the absence of any ICP queries.
3024 weight=N can be used to add bias.
3026 weighted-round-robin
3027 Load-Balance parents which should be used in a round-robin
3028 fashion with the frequency of each parent being based on the
3029 round trip time. Closer parents are used more often.
3030 Usually used for background-ping parents.
3031 weight=N can be used to add bias.
3033 carp Load-Balance parents which should be used as a CARP array.
3034 The requests will be distributed among the parents based on the
3035 CARP load balancing hash function based on their weight.
3037 userhash Load-balance parents based on the client proxy_auth or ident username.
3039 sourcehash Load-balance parents based on the client source IP.
3042 To be used only for cache peers of type "multicast".
3043 ALL members of this multicast group have "sibling"
3044 relationship with it, not "parent". This is to a multicast
3045 group when the requested object would be fetched only from
3046 a "parent" cache, anyway. It's useful, e.g., when
3047 configuring a pool of redundant Squid proxies, being
3048 members of the same multicast group.
3051 ==== PEER SELECTION OPTIONS ====
3053 weight=N use to affect the selection of a peer during any weighted
3054 peer-selection mechanisms.
3055 The weight must be an integer; default is 1,
3056 larger weights are favored more.
3057 This option does not affect parent selection if a peering
3058 protocol is not in use.
3060 basetime=N Specify a base amount to be subtracted from round trip
3062 It is subtracted before division by weight in calculating
3063 which parent to fectch from. If the rtt is less than the
3064 base time the rtt is set to a minimal value.
3066 ttl=N Specify a TTL to use when sending multicast ICP queries
3068 Only useful when sending to a multicast group.
3069 Because we don't accept ICP replies from random
3070 hosts, you must configure other group members as
3071 peers with the 'multicast-responder' option.
3073 no-delay To prevent access to this neighbor from influencing the
3076 digest-url=URL Tell Squid to fetch the cache digest (if digests are
3077 enabled) for this host from the specified URL rather
3078 than the Squid default location.
3081 ==== CARP OPTIONS ====
3083 carp-key=key-specification
3084 use a different key than the full URL to hash against the peer.
3085 the key-specification is a comma-separated list of the keywords
3086 scheme, host, port, path, params
3087 Order is not important.
3089 ==== ACCELERATOR / REVERSE-PROXY OPTIONS ====
3091 originserver Causes this parent to be contacted as an origin server.
3092 Meant to be used in accelerator setups when the peer
3096 Set the Host header of requests forwarded to this peer.
3097 Useful in accelerator setups where the server (peer)
3098 expects a certain domain name but clients may request
3099 others. ie example.com or www.example.com
3101 no-digest Disable request of cache digests.
3104 Disables requesting ICMP RTT database (NetDB).
3107 ==== AUTHENTICATION OPTIONS ====
3110 If this is a personal/workgroup proxy and your parent
3111 requires proxy authentication.
3113 Note: The string can include URL escapes (i.e. %20 for
3114 spaces). This also means % must be written as %%.
3117 Send login details received from client to this peer.
3118 Both Proxy- and WWW-Authorization headers are passed
3119 without alteration to the peer.
3120 Authentication is not required by Squid for this to work.
3122 Note: This will pass any form of authentication but
3123 only Basic auth will work through a proxy unless the
3124 connection-auth options are also used.
3126 login=PASS Send login details received from client to this peer.
3127 Authentication is not required by this option.
3129 If there are no client-provided authentication headers
3130 to pass on, but username and password are available
3131 from an external ACL user= and password= result tags
3132 they may be sent instead.
3134 Note: To combine this with proxy_auth both proxies must
3135 share the same user database as HTTP only allows for
3136 a single login (one for proxy, one for origin server).
3137 Also be warned this will expose your users proxy
3138 password to the peer. USE WITH CAUTION
3141 Send the username to the upstream cache, but with a
3142 fixed password. This is meant to be used when the peer
3143 is in another administrative domain, but it is still
3144 needed to identify each user.
3145 The star can optionally be followed by some extra
3146 information which is added to the username. This can
3147 be used to identify this proxy to the peer, similar to
3148 the login=username:password option above.
3151 If this is a personal/workgroup proxy and your parent
3152 requires a secure proxy authentication.
3153 The first principal from the default keytab or defined by
3154 the environment variable KRB5_KTNAME will be used.
3156 WARNING: The connection may transmit requests from multiple
3157 clients. Negotiate often assumes end-to-end authentication
3158 and a single-client. Which is not strictly true here.
3160 login=NEGOTIATE:principal_name
3161 If this is a personal/workgroup proxy and your parent
3162 requires a secure proxy authentication.
3163 The principal principal_name from the default keytab or
3164 defined by the environment variable KRB5_KTNAME will be
3167 WARNING: The connection may transmit requests from multiple
3168 clients. Negotiate often assumes end-to-end authentication
3169 and a single-client. Which is not strictly true here.
3171 connection-auth=on|off
3172 Tell Squid that this peer does or not support Microsoft
3173 connection oriented authentication, and any such
3174 challenges received from there should be ignored.
3175 Default is auto to automatically determine the status
3179 ==== SSL / HTTPS / TLS OPTIONS ====
3181 ssl Encrypt connections to this peer with SSL/TLS.
3183 sslcert=/path/to/ssl/certificate
3184 A client SSL certificate to use when connecting to
3187 sslkey=/path/to/ssl/key
3188 The private SSL key corresponding to sslcert above.
3189 If 'sslkey' is not specified 'sslcert' is assumed to
3190 reference a combined file containing both the
3191 certificate and the key.
3193 sslcipher=... The list of valid SSL ciphers to use when connecting
3197 The minimum TLS protocol version to permit. To control
3198 SSLv3 use the ssloptions= parameter.
3199 Supported Values: 1.0 (default), 1.1, 1.2
3201 ssloptions=... Specify various SSL implementation options:
3203 NO_SSLv3 Disallow the use of SSLv3
3205 NO_TLSv1 Disallow the use of TLSv1.0
3207 NO_TLSv1_1 Disallow the use of TLSv1.1
3209 NO_TLSv1_2 Disallow the use of TLSv1.2
3212 Always create a new key when using
3213 temporary/ephemeral DH key exchanges
3216 Disable use of RFC5077 session tickets.
3217 Some servers may have problems
3218 understanding the TLS extension due
3219 to ambiguous specification in RFC4507.
3221 ALL Enable various bug workarounds
3222 suggested as "harmless" by OpenSSL
3223 Be warned that this reduces SSL/TLS
3224 strength to some attacks.
3226 See the OpenSSL SSL_CTX_set_options documentation for a
3229 tls-cafile= PEM file containing CA certificates to use when verifying
3230 the peer certificate. May be repeated to load multiple files.
3232 sslcapath=... A directory containing additional CA certificates to
3233 use when verifying the peer certificate.
3234 Requires OpenSSL or LibreSSL.
3236 sslcrlfile=... A certificate revocation list file to use when
3237 verifying the peer certificate.
3239 sslflags=... Specify various flags modifying the SSL implementation:
3242 Accept certificates even if they fail to
3246 Don't verify the peer certificate
3247 matches the server name
3249 ssldomain= The peer name as advertised in it's certificate.
3250 Used for verifying the correctness of the received peer
3251 certificate. If not specified the peer hostname will be
3255 Enable the "Front-End-Https: On" header needed when
3256 using Squid as a SSL frontend in front of Microsoft OWA.
3257 See MS KB document Q307347 for details on this header.
3258 If set to auto the header will only be added if the
3259 request is forwarded as a https:// URL.
3262 Do not use the system default Trusted CA.
3264 ==== GENERAL OPTIONS ====
3267 A peer-specific connect timeout.
3268 Also see the peer_connect_timeout directive.
3270 connect-fail-limit=N
3271 How many times connecting to a peer must fail before
3272 it is marked as down. Standby connection failures
3273 count towards this limit. Default is 10.
3275 allow-miss Disable Squid's use of only-if-cached when forwarding
3276 requests to siblings. This is primarily useful when
3277 icp_hit_stale is used by the sibling. Excessive use
3278 of this option may result in forwarding loops. One way
3279 to prevent peering loops when using this option, is to
3280 deny cache peer usage on requests from a peer:
3282 cache_peer_access peerName deny fromPeer
3284 max-conn=N Limit the number of concurrent connections the Squid
3285 may open to this peer, including already opened idle
3286 and standby connections. There is no peer-specific
3287 connection limit by default.
3289 A peer exceeding the limit is not used for new
3290 requests unless a standby connection is available.
3292 max-conn currently works poorly with idle persistent
3293 connections: When a peer reaches its max-conn limit,
3294 and there are idle persistent connections to the peer,
3295 the peer may not be selected because the limiting code
3296 does not know whether Squid can reuse those idle
3299 standby=N Maintain a pool of N "hot standby" connections to an
3300 UP peer, available for requests when no idle
3301 persistent connection is available (or safe) to use.
3302 By default and with zero N, no such pool is maintained.
3303 N must not exceed the max-conn limit (if any).
3305 At start or after reconfiguration, Squid opens new TCP
3306 standby connections until there are N connections
3307 available and then replenishes the standby pool as
3308 opened connections are used up for requests. A used
3309 connection never goes back to the standby pool, but
3310 may go to the regular idle persistent connection pool
3311 shared by all peers and origin servers.
3313 Squid never opens multiple new standby connections
3314 concurrently. This one-at-a-time approach minimizes
3315 flooding-like effect on peers. Furthermore, just a few
3316 standby connections should be sufficient in most cases
3317 to supply most new requests with a ready-to-use
3320 Standby connections obey server_idle_pconn_timeout.
3321 For the feature to work as intended, the peer must be
3322 configured to accept and keep them open longer than
3323 the idle timeout at the connecting Squid, to minimize
3324 race conditions typical to idle used persistent
3325 connections. Default request_timeout and
3326 server_idle_pconn_timeout values ensure such a
3329 name=xxx Unique name for the peer.
3330 Required if you have multiple peers on the same host
3331 but different ports.
3332 This name can be used in cache_peer_access and similar
3333 directives to identify the peer.
3334 Can be used by outgoing access controls through the
3337 no-tproxy Do not use the client-spoof TPROXY support when forwarding
3338 requests to this peer. Use normal address selection instead.
3339 This overrides the spoof_client_ip ACL.
3341 proxy-only objects fetched from the peer will not be stored locally.
3345 NAME: cache_peer_access
3348 DEFAULT_DOC: No peer usage restrictions.
3351 Restricts usage of cache_peer proxies.
3354 cache_peer_access peer-name allow|deny [!]aclname ...
3356 For the required peer-name parameter, use either the value of the
3357 cache_peer name=value parameter or, if name=value is missing, the
3358 cache_peer hostname parameter.
3360 This directive narrows down the selection of peering candidates, but
3361 does not determine the order in which the selected candidates are
3362 contacted. That order is determined by the peer selection algorithms
3363 (see PEER SELECTION sections in the cache_peer documentation).
3365 If a deny rule matches, the corresponding peer will not be contacted
3366 for the current transaction -- Squid will not send ICP queries and
3367 will not forward HTTP requests to that peer. An allow match leaves
3368 the corresponding peer in the selection. The first match for a given
3369 peer wins for that peer.
3371 The relative order of cache_peer_access directives for the same peer
3372 matters. The relative order of any two cache_peer_access directives
3373 for different peers does not matter. To ease interpretation, it is a
3374 good idea to group cache_peer_access directives for the same peer
3377 A single cache_peer_access directive may be evaluated multiple times
3378 for a given transaction because individual peer selection algorithms
3379 may check it independently from each other. These redundant checks
3380 may be optimized away in future Squid versions.
3382 This clause only supports fast acl types.
3383 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
3387 NAME: neighbor_type_domain
3388 TYPE: hostdomaintype
3390 DEFAULT_DOC: The peer type from cache_peer directive is used for all requests to that peer.
3393 Modify the cache_peer neighbor type when passing requests
3394 about specific domains to the peer.
3397 neighbor_type_domain neighbor parent|sibling domain domain ...
3400 cache_peer foo.example.com parent 3128 3130
3401 neighbor_type_domain foo.example.com sibling .au .de
3403 The above configuration treats all requests to foo.example.com as a
3404 parent proxy unless the request is for a .au or .de ccTLD domain name.
3407 NAME: dead_peer_timeout
3411 LOC: Config.Timeout.deadPeer
3413 This controls how long Squid waits to declare a peer cache
3414 as "dead." If there are no ICP replies received in this
3415 amount of time, Squid will declare the peer dead and not
3416 expect to receive any further ICP replies. However, it
3417 continues to send ICP queries, and will mark the peer as
3418 alive upon receipt of the first subsequent ICP reply.
3420 This timeout also affects when Squid expects to receive ICP
3421 replies from peers. If more than 'dead_peer' seconds have
3422 passed since the last ICP reply was received, Squid will not
3423 expect to receive an ICP reply on the next query. Thus, if
3424 your time between requests is greater than this timeout, you
3425 will see a lot of requests sent DIRECT to origin servers
3426 instead of to your parents.
3429 NAME: forward_max_tries
3432 LOC: Config.forward_max_tries
3434 Controls how many different forward paths Squid will try
3435 before giving up. See also forward_timeout.
3437 NOTE: connect_retries (default: none) can make each of these
3438 possible forwarding paths be tried multiple times.
3442 MEMORY CACHE OPTIONS
3443 -----------------------------------------------------------------------------
3450 LOC: Config.memMaxSize
3452 NOTE: THIS PARAMETER DOES NOT SPECIFY THE MAXIMUM PROCESS SIZE.
3453 IT ONLY PLACES A LIMIT ON HOW MUCH ADDITIONAL MEMORY SQUID WILL
3454 USE AS A MEMORY CACHE OF OBJECTS. SQUID USES MEMORY FOR OTHER
3455 THINGS AS WELL. SEE THE SQUID FAQ SECTION 8 FOR DETAILS.
3457 'cache_mem' specifies the ideal amount of memory to be used
3459 * In-Transit objects
3461 * Negative-Cached objects
3463 Data for these objects are stored in 4 KB blocks. This
3464 parameter specifies the ideal upper limit on the total size of
3465 4 KB blocks allocated. In-Transit objects take the highest
3468 In-transit objects have priority over the others. When
3469 additional space is needed for incoming data, negative-cached
3470 and hot objects will be released. In other words, the
3471 negative-cached and hot objects will fill up any unused space
3472 not needed for in-transit objects.
3474 If circumstances require, this limit will be exceeded.
3475 Specifically, if your incoming request rate requires more than
3476 'cache_mem' of memory to hold in-transit objects, Squid will
3477 exceed this limit to satisfy the new requests. When the load
3478 decreases, blocks will be freed until the high-water mark is
3479 reached. Thereafter, blocks will be used to store hot
3482 If shared memory caching is enabled, Squid does not use the shared
3483 cache space for in-transit objects, but they still consume as much
3484 local memory as they need. For more details about the shared memory
3485 cache, see memory_cache_shared.
3488 NAME: maximum_object_size_in_memory
3492 LOC: Config.Store.maxInMemObjSize
3494 Objects greater than this size will not be attempted to kept in
3495 the memory cache. This should be set high enough to keep objects
3496 accessed frequently in memory to improve performance whilst low
3497 enough to keep larger objects from hoarding cache_mem.
3500 NAME: memory_cache_shared
3503 LOC: Config.memShared
3505 DEFAULT_DOC: "on" where supported if doing memory caching with multiple SMP workers.
3507 Controls whether the memory cache is shared among SMP workers.
3509 The shared memory cache is meant to occupy cache_mem bytes and replace
3510 the non-shared memory cache, although some entities may still be
3511 cached locally by workers for now (e.g., internal and in-transit
3512 objects may be served from a local memory cache even if shared memory
3513 caching is enabled).
3515 By default, the memory cache is shared if and only if all of the
3516 following conditions are satisfied: Squid runs in SMP mode with
3517 multiple workers, cache_mem is positive, and Squid environment
3518 supports required IPC primitives (e.g., POSIX shared memory segments
3519 and GCC-style atomic operations).
3521 To avoid blocking locks, shared memory uses opportunistic algorithms
3522 that do not guarantee that every cachable entity that could have been
3523 shared among SMP workers will actually be shared.
3525 Currently, entities exceeding 32KB in size cannot be shared.
3528 NAME: memory_cache_mode
3532 DEFAULT_DOC: Keep the most recently fetched objects in memory
3534 Controls which objects to keep in the memory cache (cache_mem)
3536 always Keep most recently fetched objects in memory (default)
3538 disk Only disk cache hits are kept in memory, which means
3539 an object must first be cached on disk and then hit
3540 a second time before cached in memory.
3542 network Only objects fetched from network is kept in memory
3545 NAME: memory_replacement_policy
3547 LOC: Config.memPolicy
3550 The memory replacement policy parameter determines which
3551 objects are purged from memory when memory space is needed.
3553 See cache_replacement_policy for details on algorithms.
3558 -----------------------------------------------------------------------------
3561 NAME: cache_replacement_policy
3563 LOC: Config.replPolicy
3566 The cache replacement policy parameter determines which
3567 objects are evicted (replaced) when disk space is needed.
3569 lru : Squid's original list based LRU policy
3570 heap GDSF : Greedy-Dual Size Frequency
3571 heap LFUDA: Least Frequently Used with Dynamic Aging
3572 heap LRU : LRU policy implemented using a heap
3574 Applies to any cache_dir lines listed below this directive.
3576 The LRU policies keeps recently referenced objects.
3578 The heap GDSF policy optimizes object hit rate by keeping smaller
3579 popular objects in cache so it has a better chance of getting a
3580 hit. It achieves a lower byte hit rate than LFUDA though since
3581 it evicts larger (possibly popular) objects.
3583 The heap LFUDA policy keeps popular objects in cache regardless of
3584 their size and thus optimizes byte hit rate at the expense of
3585 hit rate since one large, popular object will prevent many
3586 smaller, slightly less popular objects from being cached.
3588 Both policies utilize a dynamic aging mechanism that prevents
3589 cache pollution that can otherwise occur with frequency-based
3590 replacement policies.
3592 NOTE: if using the LFUDA replacement policy you should increase
3593 the value of maximum_object_size above its default of 4 MB to
3594 to maximize the potential byte hit rate improvement of LFUDA.
3596 For more information about the GDSF and LFUDA cache replacement
3597 policies see http://www.hpl.hp.com/techreports/1999/HPL-1999-69.html
3598 and http://fog.hpl.external.hp.com/techreports/98/HPL-98-173.html.
3601 NAME: minimum_object_size
3605 DEFAULT_DOC: no limit
3606 LOC: Config.Store.minObjectSize
3608 Objects smaller than this size will NOT be saved on disk. The
3609 value is specified in bytes, and the default is 0 KB, which
3610 means all responses can be stored.
3613 NAME: maximum_object_size
3617 LOC: Config.Store.maxObjectSize
3619 Set the default value for max-size parameter on any cache_dir.
3620 The value is specified in bytes, and the default is 4 MB.
3622 If you wish to get a high BYTES hit ratio, you should probably
3623 increase this (one 32 MB object hit counts for 3200 10KB
3626 If you wish to increase hit ratio more than you want to
3627 save bandwidth you should leave this low.
3629 NOTE: if using the LFUDA replacement policy you should increase
3630 this value to maximize the byte hit rate improvement of LFUDA!
3631 See cache_replacement_policy for a discussion of this policy.
3637 DEFAULT_DOC: No disk cache. Store cache ojects only in memory.
3638 LOC: Config.cacheSwap
3641 cache_dir Type Directory-Name Fs-specific-data [options]
3643 You can specify multiple cache_dir lines to spread the
3644 cache among different disk partitions.
3646 Type specifies the kind of storage system to use. Only "ufs"
3647 is built by default. To enable any of the other storage systems
3648 see the --enable-storeio configure option.
3650 'Directory' is a top-level directory where cache swap
3651 files will be stored. If you want to use an entire disk
3652 for caching, this can be the mount-point directory.
3653 The directory must exist and be writable by the Squid
3654 process. Squid will NOT create this directory for you.
3656 In SMP configurations, cache_dir must not precede the workers option
3657 and should use configuration macros or conditionals to give each
3658 worker interested in disk caching a dedicated cache directory.
3661 ==== The ufs store type ====
3663 "ufs" is the old well-known Squid storage format that has always
3667 cache_dir ufs Directory-Name Mbytes L1 L2 [options]
3669 'Mbytes' is the amount of disk space (MB) to use under this
3670 directory. The default is 100 MB. Change this to suit your
3671 configuration. Do NOT put the size of your disk drive here.
3672 Instead, if you want Squid to use the entire disk drive,
3673 subtract 20% and use that value.
3675 'L1' is the number of first-level subdirectories which
3676 will be created under the 'Directory'. The default is 16.
3678 'L2' is the number of second-level subdirectories which
3679 will be created under each first-level directory. The default
3683 ==== The aufs store type ====
3685 "aufs" uses the same storage format as "ufs", utilizing
3686 POSIX-threads to avoid blocking the main Squid process on
3687 disk-I/O. This was formerly known in Squid as async-io.
3690 cache_dir aufs Directory-Name Mbytes L1 L2 [options]
3692 see argument descriptions under ufs above
3695 ==== The diskd store type ====
3697 "diskd" uses the same storage format as "ufs", utilizing a
3698 separate process to avoid blocking the main Squid process on
3702 cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n]
3704 see argument descriptions under ufs above
3706 Q1 specifies the number of unacknowledged I/O requests when Squid
3707 stops opening new files. If this many messages are in the queues,
3708 Squid won't open new files. Default is 64
3710 Q2 specifies the number of unacknowledged messages when Squid
3711 starts blocking. If this many messages are in the queues,
3712 Squid blocks until it receives some replies. Default is 72
3714 When Q1 < Q2 (the default), the cache directory is optimized
3715 for lower response time at the expense of a decrease in hit
3716 ratio. If Q1 > Q2, the cache directory is optimized for
3717 higher hit ratio at the expense of an increase in response
3721 ==== The rock store type ====
3724 cache_dir rock Directory-Name Mbytes [options]
3726 The Rock Store type is a database-style storage. All cached
3727 entries are stored in a "database" file, using fixed-size slots.
3728 A single entry occupies one or more slots.
3730 If possible, Squid using Rock Store creates a dedicated kid
3731 process called "disker" to avoid blocking Squid worker(s) on disk
3732 I/O. One disker kid is created for each rock cache_dir. Diskers
3733 are created only when Squid, running in daemon mode, has support
3734 for the IpcIo disk I/O module.
3736 swap-timeout=msec: Squid will not start writing a miss to or
3737 reading a hit from disk if it estimates that the swap operation
3738 will take more than the specified number of milliseconds. By
3739 default and when set to zero, disables the disk I/O time limit
3740 enforcement. Ignored when using blocking I/O module because
3741 blocking synchronous I/O does not allow Squid to estimate the
3742 expected swap wait time.
3744 max-swap-rate=swaps/sec: Artificially limits disk access using
3745 the specified I/O rate limit. Swap out requests that
3746 would cause the average I/O rate to exceed the limit are
3747 delayed. Individual swap in requests (i.e., hits or reads) are
3748 not delayed, but they do contribute to measured swap rate and
3749 since they are placed in the same FIFO queue as swap out
3750 requests, they may wait longer if max-swap-rate is smaller.
3751 This is necessary on file systems that buffer "too
3752 many" writes and then start blocking Squid and other processes
3753 while committing those writes to disk. Usually used together
3754 with swap-timeout to avoid excessive delays and queue overflows
3755 when disk demand exceeds available disk "bandwidth". By default
3756 and when set to zero, disables the disk I/O rate limit
3757 enforcement. Currently supported by IpcIo module only.
3759 slot-size=bytes: The size of a database "record" used for
3760 storing cached responses. A cached response occupies at least
3761 one slot and all database I/O is done using individual slots so
3762 increasing this parameter leads to more disk space waste while
3763 decreasing it leads to more disk I/O overheads. Should be a
3764 multiple of your operating system I/O page size. Defaults to
3765 16KBytes. A housekeeping header is stored with each slot and
3766 smaller slot-sizes will be rejected. The header is smaller than
3770 ==== COMMON OPTIONS ====
3772 no-store no new objects should be stored to this cache_dir.
3774 min-size=n the minimum object size in bytes this cache_dir
3775 will accept. It's used to restrict a cache_dir
3776 to only store large objects (e.g. AUFS) while
3777 other stores are optimized for smaller objects
3781 max-size=n the maximum object size in bytes this cache_dir
3783 The value in maximum_object_size directive sets
3784 the default unless more specific details are
3785 available (ie a small store capacity).
3787 Note: To make optimal use of the max-size limits you should order
3788 the cache_dir lines with the smallest max-size value first.
3792 # Uncomment and adjust the following to add a disk cache directory.
3793 #cache_dir ufs @DEFAULT_SWAP_DIR@ 100 16 256
3797 NAME: store_dir_select_algorithm
3799 LOC: Config.store_dir_select_algorithm
3802 How Squid selects which cache_dir to use when the response
3803 object will fit into more than one.
3805 Regardless of which algorithm is used the cache_dir min-size
3806 and max-size parameters are obeyed. As such they can affect
3807 the selection algorithm by limiting the set of considered
3814 This algorithm is suited to caches with similar cache_dir
3815 sizes and disk speeds.
3817 The disk with the least I/O pending is selected.
3818 When there are multiple disks with the same I/O load ranking
3819 the cache_dir with most available capacity is selected.
3821 When a mix of cache_dir sizes are configured the faster disks
3822 have a naturally lower I/O loading and larger disks have more
3823 capacity. So space used to store objects and data throughput
3824 may be very unbalanced towards larger disks.
3829 This algorithm is suited to caches with unequal cache_dir
3832 Each cache_dir is selected in a rotation. The next suitable
3835 Available cache_dir capacity is only considered in relation
3836 to whether the object will fit and meets the min-size and
3837 max-size parameters.
3839 Disk I/O loading is only considered to prevent overload on slow
3840 disks. This algorithm does not spread objects by size, so any
3841 I/O loading per-disk may appear very unbalanced and volatile.
3843 If several cache_dirs use similar min-size, max-size, or other
3844 limits to to reject certain responses, then do not group such
3845 cache_dir lines together, to avoid round-robin selection bias
3846 towards the first cache_dir after the group. Instead, interleave
3847 cache_dir lines from different groups. For example:
3849 store_dir_select_algorithm round-robin
3850 cache_dir rock /hdd1 ... min-size=100000
3851 cache_dir rock /ssd1 ... max-size=99999
3852 cache_dir rock /hdd2 ... min-size=100000
3853 cache_dir rock /ssd2 ... max-size=99999
3854 cache_dir rock /hdd3 ... min-size=100000
3855 cache_dir rock /ssd3 ... max-size=99999
3858 NAME: max_open_disk_fds
3860 LOC: Config.max_open_disk_fds
3862 DEFAULT_DOC: no limit
3864 To avoid having disk as the I/O bottleneck Squid can optionally
3865 bypass the on-disk cache if more than this amount of disk file
3866 descriptors are open.
3868 A value of 0 indicates no limit.
3871 NAME: cache_swap_low
3872 COMMENT: (percent, 0-100)
3875 LOC: Config.Swap.lowWaterMark
3877 The low-water mark for AUFS/UFS/diskd cache object eviction by
3878 the cache_replacement_policy algorithm.
3880 Removal begins when the swap (disk) usage of a cache_dir is
3881 above this low-water mark and attempts to maintain utilization
3882 near the low-water mark.
3884 As swap utilization increases towards the high-water mark set
3885 by cache_swap_high object eviction becomes more agressive.
3887 The value difference in percentages between low- and high-water
3888 marks represent an eviction rate of 300 objects per second and
3889 the rate continues to scale in agressiveness by multiples of
3890 this above the high-water mark.
3892 Defaults are 90% and 95%. If you have a large cache, 5% could be
3893 hundreds of MB. If this is the case you may wish to set these
3894 numbers closer together.
3896 See also cache_swap_high and cache_replacement_policy
3899 NAME: cache_swap_high
3900 COMMENT: (percent, 0-100)
3903 LOC: Config.Swap.highWaterMark
3905 The high-water mark for AUFS/UFS/diskd cache object eviction by
3906 the cache_replacement_policy algorithm.
3908 Removal begins when the swap (disk) usage of a cache_dir is
3909 above the low-water mark set by cache_swap_low and attempts to
3910 maintain utilization near the low-water mark.
3912 As swap utilization increases towards this high-water mark object
3913 eviction becomes more agressive.
3915 The value difference in percentages between low- and high-water
3916 marks represent an eviction rate of 300 objects per second and
3917 the rate continues to scale in agressiveness by multiples of
3918 this above the high-water mark.
3920 Defaults are 90% and 95%. If you have a large cache, 5% could be
3921 hundreds of MB. If this is the case you may wish to set these
3922 numbers closer together.
3924 See also cache_swap_low and cache_replacement_policy
3929 -----------------------------------------------------------------------------
3936 DEFAULT_DOC: The format definitions squid, common, combined, referrer, useragent are built in.
3940 logformat <name> <format specification>
3942 Defines an access log format.
3944 The <format specification> is a string with embedded % format codes
3946 % format codes all follow the same basic structure where all but
3947 the formatcode is optional. Output strings are automatically escaped
3948 as required according to their context and the output format
3949 modifiers are usually not needed, but can be specified if an explicit
3950 output format is desired.
3952 % ["|[|'|#|/] [-] [[0]width] [{arg}] formatcode [{arg}]
3954 " output in quoted string format
3955 [ output in squid text log format as used by log_mime_hdrs
3956 # output in URL quoted format
3957 / output in shell \-escaped format
3962 width minimum and/or maximum field width:
3963 [width_min][.width_max]
3964 When minimum starts with 0, the field is zero-padded.
3965 String values exceeding maximum width are truncated.
3967 {arg} argument such as header name etc. This field may be
3968 placed before or after the token, but not both at once.
3972 % a literal % character
3973 sn Unique sequence number per log line entry
3974 err_code The ID of an error response served by Squid or
3975 a similar internal error identifier.
3976 err_detail Additional err_code-dependent error information.
3977 note The annotation specified by the argument. Also
3978 logs the adaptation meta headers set by the
3979 adaptation_meta configuration parameter.
3980 If no argument given all annotations logged.
3981 The argument may include a separator to use with
3984 By default, multiple note values are separated with ","
3985 and multiple notes are separated with "\r\n".
3986 When logging named notes with %{name}note, the
3987 explicitly configured separator is used between note
3988 values. When logging all notes with %note, the
3989 explicitly configured separator is used between
3990 individual notes. There is currently no way to
3991 specify both value and notes separators when logging
3992 all notes with %note.
3994 Connection related format codes:
3996 >a Client source IP address
3998 >p Client source port
3999 >eui Client source EUI (MAC address, EUI-48 or EUI-64 identifier)
4000 >la Local IP address the client connected to
4001 >lp Local port number the client connected to
4002 >qos Client connection TOS/DSCP value set by Squid
4003 >nfmark Client connection netfilter mark set by Squid
4005 la Local listening IP address the client connection was connected to.
4006 lp Local listening port number the client connection was connected to.
4008 <a Server IP address of the last server or peer connection
4009 <A Server FQDN or peer name
4010 <p Server port number of the last server or peer connection
4011 <la Local IP address of the last server or peer connection
4012 <lp Local port number of the last server or peer connection
4013 <qos Server connection TOS/DSCP value set by Squid
4014 <nfmark Server connection netfilter mark set by Squid
4016 Time related format codes:
4018 ts Seconds since epoch
4019 tu subsecond time (milliseconds)
4020 tl Local time. Optional strftime format argument
4021 default %d/%b/%Y:%H:%M:%S %z
4022 tg GMT time. Optional strftime format argument
4023 default %d/%b/%Y:%H:%M:%S %z
4024 tr Response time (milliseconds)
4025 dt Total time spent making DNS lookups (milliseconds)
4026 tS Approximate master transaction start time in
4027 <full seconds since epoch>.<fractional seconds> format.
4028 Currently, Squid considers the master transaction
4029 started when a complete HTTP request header initiating
4030 the transaction is received from the client. This is
4031 the same value that Squid uses to calculate transaction
4032 response time when logging %tr to access.log. Currently,
4033 Squid uses millisecond resolution for %tS values,
4034 similar to the default access.log "current time" field
4037 Access Control related format codes:
4039 et Tag returned by external acl
4040 ea Log string returned by external acl
4041 un User name (any available)
4042 ul User name from authentication
4043 ue User name from external acl helper
4044 ui User name from ident
4045 un A user name. Expands to the first available name
4046 from the following list of information sources:
4047 - authenticated user name, like %ul
4048 - user name supplied by an external ACL, like %ue
4049 - SSL client name, like %us
4050 - ident user name, like %ui
4051 credentials Client credentials. The exact meaning depends on
4052 the authentication scheme: For Basic authentication,
4053 it is the password; for Digest, the realm sent by the
4054 client; for NTLM and Negotiate, the client challenge
4055 or client credentials prefixed with "YR " or "KK ".
4057 HTTP related format codes:
4061 [http::]rm Request method (GET/POST etc)
4062 [http::]>rm Request method from client
4063 [http::]<rm Request method sent to server or peer
4064 [http::]ru Request URL from client (historic, filtered for logging)
4065 [http::]>ru Request URL from client
4066 [http::]<ru Request URL sent to server or peer
4067 [http::]>rs Request URL scheme from client
4068 [http::]<rs Request URL scheme sent to server or peer
4069 [http::]>rd Request URL domain from client
4070 [http::]<rd Request URL domain sent to server or peer
4071 [http::]>rP Request URL port from client
4072 [http::]<rP Request URL port sent to server or peer
4073 [http::]rp Request URL path excluding hostname
4074 [http::]>rp Request URL path excluding hostname from client
4075 [http::]<rp Request URL path excluding hostname sent to server or peer
4076 [http::]rv Request protocol version
4077 [http::]>rv Request protocol version from client
4078 [http::]<rv Request protocol version sent to server or peer
4080 [http::]>h Original received request header.
4081 Usually differs from the request header sent by
4082 Squid, although most fields are often preserved.
4083 Accepts optional header field name/value filter
4084 argument using name[:[separator]element] format.
4085 [http::]>ha Received request header after adaptation and
4086 redirection (pre-cache REQMOD vectoring point).
4087 Usually differs from the request header sent by
4088 Squid, although most fields are often preserved.
4089 Optional header name argument as for >h
4093 [http::]<Hs HTTP status code received from the next hop
4094 [http::]>Hs HTTP status code sent to the client
4096 [http::]<h Reply header. Optional header name argument
4099 [http::]mt MIME content type
4104 [http::]st Total size of request + reply traffic with client
4105 [http::]>st Total size of request received from client.
4106 Excluding chunked encoding bytes.
4107 [http::]<st Total size of reply sent to client (after adaptation)
4109 [http::]>sh Size of request headers received from client
4110 [http::]<sh Size of reply headers sent to client (after adaptation)
4112 [http::]<sH Reply high offset sent
4113 [http::]<sS Upstream object size
4115 [http::]<bs Number of HTTP-equivalent message body bytes
4116 received from the next hop, excluding chunked
4117 transfer encoding and control messages.
4118 Generated FTP/Gopher listings are treated as
4123 [http::]<pt Peer response time in milliseconds. The timer starts
4124 when the last request byte is sent to the next hop
4125 and stops when the last response byte is received.
4126 [http::]<tt Total time in milliseconds. The timer
4127 starts with the first connect request (or write I/O)
4128 sent to the first selected peer. The timer stops
4129 with the last I/O with the last peer.
4131 Squid handling related format codes:
4133 Ss Squid request status (TCP_MISS etc)
4134 Sh Squid hierarchy status (DEFAULT_PARENT etc)
4136 SSL-related format codes:
4138 ssl::bump_mode SslBump decision for the transaction:
4140 For CONNECT requests that initiated bumping of
4141 a connection and for any request received on
4142 an already bumped connection, Squid logs the
4143 corresponding SslBump mode ("server-first" or
4144 "client-first"). See the ssl_bump option for
4145 more information about these modes.
4147 A "none" token is logged for requests that
4148 triggered "ssl_bump" ACL evaluation matching
4149 either a "none" rule or no rules at all.
4151 In all other cases, a single dash ("-") is
4154 ssl::>sni SSL client SNI sent to Squid. Available only
4155 after the peek, stare, or splice SSL bumping
4159 The Subject field of the received client
4160 SSL certificate or a dash ('-') if Squid has
4161 received an invalid/malformed certificate or
4162 no certificate at all. Consider encoding the
4163 logged value because Subject often has spaces.
4166 The Issuer field of the received client
4167 SSL certificate or a dash ('-') if Squid has
4168 received an invalid/malformed certificate or
4169 no certificate at all. Consider encoding the
4170 logged value because Issuer often has spaces.
4173 The list of certificate validation errors
4174 detected by Squid (including OpenSSL and
4175 certificate validation helper components). The
4176 errors are listed in the discovery order. By
4177 default, the error codes are separated by ':'.
4178 Accepts an optional separator argument.
4180 If ICAP is enabled, the following code becomes available (as
4181 well as ICAP log codes documented with the icap_log option):
4183 icap::tt Total ICAP processing time for the HTTP
4184 transaction. The timer ticks when ICAP
4185 ACLs are checked and when ICAP
4186 transaction is in progress.
4188 If adaptation is enabled the following codes become available:
4190 adapt::<last_h The header of the last ICAP response or
4191 meta-information from the last eCAP
4192 transaction related to the HTTP transaction.
4193 Like <h, accepts an optional header name
4196 adapt::sum_trs Summed adaptation transaction response
4197 times recorded as a comma-separated list in
4198 the order of transaction start time. Each time
4199 value is recorded as an integer number,
4200 representing response time of one or more
4201 adaptation (ICAP or eCAP) transaction in
4202 milliseconds. When a failed transaction is
4203 being retried or repeated, its time is not
4204 logged individually but added to the
4205 replacement (next) transaction. See also:
4208 adapt::all_trs All adaptation transaction response times.
4209 Same as adaptation_strs but response times of
4210 individual transactions are never added
4211 together. Instead, all transaction response
4212 times are recorded individually.
4214 You can prefix adapt::*_trs format codes with adaptation
4215 service name in curly braces to record response time(s) specific
4216 to that service. For example: %{my_service}adapt::sum_trs
4218 The default formats available (which do not need re-defining) are:
4220 logformat squid %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %[un %Sh/%<a %mt
4221 logformat common %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st %Ss:%Sh
4222 logformat combined %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
4223 logformat referrer %ts.%03tu %>a %{Referer}>h %ru
4224 logformat useragent %>a [%tl] "%{User-Agent}>h"
4226 NOTE: When the log_mime_hdrs directive is set to ON.
4227 The squid, common and combined formats have a safely encoded copy
4228 of the mime headers appended to each line within a pair of brackets.
4230 NOTE: The common and combined formats are not quite true to the Apache definition.
4231 The logs from Squid contain an extra status and hierarchy code appended.
4235 NAME: access_log cache_access_log
4237 LOC: Config.Log.accesslogs
4238 DEFAULT_IF_NONE: daemon:@DEFAULT_ACCESS_LOG@ squid
4240 Configures whether and how Squid logs HTTP and ICP transactions.
4241 If access logging is enabled, a single line is logged for every
4242 matching HTTP or ICP request. The recommended directive formats are:
4244 access_log <module>:<place> [option ...] [acl acl ...]
4245 access_log none [acl acl ...]
4247 The following directive format is accepted but may be deprecated:
4248 access_log <module>:<place> [<logformat name> [acl acl ...]]
4250 In most cases, the first ACL name must not contain the '=' character
4251 and should not be equal to an existing logformat name. You can always
4252 start with an 'all' ACL to work around those restrictions.
4254 Will log to the specified module:place using the specified format (which
4255 must be defined in a logformat directive) those entries which match
4256 ALL the acl's specified (which must be defined in acl clauses).
4257 If no acl is specified, all requests will be logged to this destination.
4259 ===== Available options for the recommended directive format =====
4261 logformat=name Names log line format (either built-in or
4262 defined by a logformat directive). Defaults
4265 buffer-size=64KB Defines approximate buffering limit for log
4266 records (see buffered_logs). Squid should not
4267 keep more than the specified size and, hence,
4268 should flush records before the buffer becomes
4269 full to avoid overflows under normal
4270 conditions (the exact flushing algorithm is
4271 module-dependent though). The on-error option
4272 controls overflow handling.
4274 on-error=die|drop Defines action on unrecoverable errors. The
4275 'drop' action ignores (i.e., does not log)
4276 affected log records. The default 'die' action
4277 kills the affected worker. The drop action
4278 support has not been tested for modules other
4281 rotate=N Specifies the number of log file rotations to
4282 make when you run 'squid -k rotate'. The default
4283 is to obey the logfile_rotate directive. Setting
4284 rotate=0 will disable the file name rotation,
4285 but the log files are still closed and re-opened.
4286 This will enable you to rename the logfiles
4287 yourself just before sending the rotate signal.
4288 Only supported by the stdio module.
4290 ===== Modules Currently available =====
4292 none Do not log any requests matching these ACL.
4293 Do not specify Place or logformat name.
4295 stdio Write each log line to disk immediately at the completion of
4297 Place: the filename and path to be written.
4299 daemon Very similar to stdio. But instead of writing to disk the log
4300 line is passed to a daemon helper for asychronous handling instead.
4301 Place: varies depending on the daemon.
4303 log_file_daemon Place: the file name and path to be written.
4305 syslog To log each request via syslog facility.
4306 Place: The syslog facility and priority level for these entries.
4307 Place Format: facility.priority
4309 where facility could be any of:
4310 authpriv, daemon, local0 ... local7 or user.
4312 And priority could be any of:
4313 err, warning, notice, info, debug.
4315 udp To send each log line as text data to a UDP receiver.
4316 Place: The destination host name or IP and port.
4317 Place Format: //host:port
4319 tcp To send each log line as text data to a TCP receiver.
4320 Lines may be accumulated before sending (see buffered_logs).
4321 Place: The destination host name or IP and port.
4322 Place Format: //host:port
4325 access_log daemon:@DEFAULT_ACCESS_LOG@ squid
4331 LOC: Config.Log.icaplogs
4334 ICAP log files record ICAP transaction summaries, one line per
4337 The icap_log option format is:
4338 icap_log <filepath> [<logformat name> [acl acl ...]]
4339 icap_log none [acl acl ...]]
4341 Please see access_log option documentation for details. The two
4342 kinds of logs share the overall configuration approach and many
4345 ICAP processing of a single HTTP message or transaction may
4346 require multiple ICAP transactions. In such cases, multiple
4347 ICAP transaction log lines will correspond to a single access
4350 ICAP log uses logformat codes that make sense for an ICAP
4351 transaction. Header-related codes are applied to the HTTP header
4352 embedded in an ICAP server response, with the following caveats:
4353 For REQMOD, there is no HTTP response header unless the ICAP
4354 server performed request satisfaction. For RESPMOD, the HTTP
4355 request header is the header sent to the ICAP server. For
4356 OPTIONS, there are no HTTP headers.
4358 The following format codes are also available for ICAP logs:
4360 icap::<A ICAP server IP address. Similar to <A.
4362 icap::<service_name ICAP service name from the icap_service
4363 option in Squid configuration file.
4365 icap::ru ICAP Request-URI. Similar to ru.
4367 icap::rm ICAP request method (REQMOD, RESPMOD, or
4368 OPTIONS). Similar to existing rm.
4370 icap::>st Bytes sent to the ICAP server (TCP payload
4371 only; i.e., what Squid writes to the socket).
4373 icap::<st Bytes received from the ICAP server (TCP
4374 payload only; i.e., what Squid reads from
4377 icap::<bs Number of message body bytes received from the
4378 ICAP server. ICAP message body, if any, usually
4379 includes encapsulated HTTP message headers and
4380 possibly encapsulated HTTP message body. The
4381 HTTP body part is dechunked before its size is
4384 icap::tr Transaction response time (in
4385 milliseconds). The timer starts when
4386 the ICAP transaction is created and
4387 stops when the transaction is completed.
4390 icap::tio Transaction I/O time (in milliseconds). The
4391 timer starts when the first ICAP request
4392 byte is scheduled for sending. The timers
4393 stops when the last byte of the ICAP response
4396 icap::to Transaction outcome: ICAP_ERR* for all
4397 transaction errors, ICAP_OPT for OPTION
4398 transactions, ICAP_ECHO for 204
4399 responses, ICAP_MOD for message
4400 modification, and ICAP_SAT for request
4401 satisfaction. Similar to Ss.
4403 icap::Hs ICAP response status code. Similar to Hs.
4405 icap::>h ICAP request header(s). Similar to >h.
4407 icap::<h ICAP response header(s). Similar to <h.
4409 The default ICAP log format, which can be used without an explicit
4410 definition, is called icap_squid:
4412 logformat icap_squid %ts.%03tu %6icap::tr %>a %icap::to/%03icap::Hs %icap::<size %icap::rm %icap::ru% %un -/%icap::<A -
4414 See also: logformat, log_icap, and %adapt::<last_h
4417 NAME: logfile_daemon
4419 DEFAULT: @DEFAULT_LOGFILED@
4420 LOC: Log::TheConfig.logfile_daemon
4422 Specify the path to the logfile-writing daemon. This daemon is
4423 used to write the access and store logs, if configured.
4425 Squid sends a number of commands to the log daemon:
4426 L<data>\n - logfile data
4431 r<n>\n - set rotate count to <n>
4432 b<n>\n - 1 = buffer output, 0 = don't buffer output
4434 No responses is expected.
4437 NAME: stats_collection
4439 LOC: Config.accessList.stats_collection
4441 DEFAULT_DOC: Allow logging for all transactions.
4442 COMMENT: allow|deny acl acl...
4444 This options allows you to control which requests gets accounted
4445 in performance counters.
4447 This clause only supports fast acl types.
4448 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4451 NAME: cache_store_log
4454 LOC: Config.Log.store
4456 Logs the activities of the storage manager. Shows which
4457 objects are ejected from the cache, and which objects are
4458 saved and for how long.
4459 There are not really utilities to analyze this data, so you can safely
4460 disable it (the default).
4462 Store log uses modular logging outputs. See access_log for the list
4463 of modules supported.
4466 cache_store_log stdio:@DEFAULT_STORE_LOG@
4467 cache_store_log daemon:@DEFAULT_STORE_LOG@
4470 NAME: cache_swap_state cache_swap_log
4472 LOC: Config.Log.swap
4474 DEFAULT_DOC: Store the journal inside its cache_dir
4476 Location for the cache "swap.state" file. This index file holds
4477 the metadata of objects saved on disk. It is used to rebuild
4478 the cache during startup. Normally this file resides in each
4479 'cache_dir' directory, but you may specify an alternate
4480 pathname here. Note you must give a full filename, not just
4481 a directory. Since this is the index for the whole object
4482 list you CANNOT periodically rotate it!
4484 If %s can be used in the file name it will be replaced with a
4485 a representation of the cache_dir name where each / is replaced
4486 with '.'. This is needed to allow adding/removing cache_dir
4487 lines when cache_swap_log is being used.
4489 If have more than one 'cache_dir', and %s is not used in the name
4490 these swap logs will have names such as:
4496 The numbered extension (which is added automatically)
4497 corresponds to the order of the 'cache_dir' lines in this
4498 configuration file. If you change the order of the 'cache_dir'
4499 lines in this file, these index files will NOT correspond to
4500 the correct 'cache_dir' entry (unless you manually rename
4501 them). We recommend you do NOT use this option. It is
4502 better to keep these index files in each 'cache_dir' directory.
4505 NAME: logfile_rotate
4508 LOC: Config.Log.rotateNumber
4510 Specifies the default number of logfile rotations to make when you
4511 type 'squid -k rotate'. The default is 10, which will rotate
4512 with extensions 0 through 9. Setting logfile_rotate to 0 will
4513 disable the file name rotation, but the logfiles are still closed
4514 and re-opened. This will enable you to rename the logfiles
4515 yourself just before sending the rotate signal.
4517 Note, from Squid-3.1 this option is only a default for cache.log,
4518 that log can be rotated separately by using debug_options.
4520 Note, from Squid-3.6 this option is only a default for access.log
4521 recorded by stdio: module. Those logs can be rotated separately by
4522 using the rotate=N option on their access_log directive.
4524 Note, the 'squid -k rotate' command normally sends a USR1
4525 signal to the running squid process. In certain situations
4526 (e.g. on Linux with Async I/O), USR1 is used for other
4527 purposes, so -k rotate uses another signal. It is best to get
4528 in the habit of using 'squid -k rotate' instead of 'kill -USR1
4535 DEFAULT: @DEFAULT_MIME_TABLE@
4536 LOC: Config.mimeTablePathname
4538 Path to Squid's icon configuration file.
4540 You shouldn't need to change this, but the default file contains
4541 examples and formatting information if you do.
4547 LOC: Config.onoff.log_mime_hdrs
4550 The Cache can record both the request and the response MIME
4551 headers for each HTTP transaction. The headers are encoded
4552 safely and will appear as two bracketed fields at the end of
4553 the access log (for either the native or httpd-emulated log
4554 formats). To enable this logging set log_mime_hdrs to 'on'.
4559 DEFAULT: @DEFAULT_PID_FILE@
4560 LOC: Config.pidFilename
4562 A filename to write the process-id to. To disable, enter "none".
4565 NAME: client_netmask
4567 LOC: Config.Addrs.client_netmask
4569 DEFAULT_DOC: Log full client IP address
4571 A netmask for client addresses in logfiles and cachemgr output.
4572 Change this to protect the privacy of your cache clients.
4573 A netmask of 255.255.255.0 will log all IP's in that range with
4574 the last digit set to '0'.
4577 NAME: strip_query_terms
4579 LOC: Config.onoff.strip_query_terms
4582 By default, Squid strips query terms from requested URLs before
4583 logging. This protects your user's privacy and reduces log size.
4585 When investigating HIT/MISS or other caching behaviour you
4586 will need to disable this to see the full URL used by Squid.
4593 LOC: Config.onoff.buffered_logs
4595 Whether to write/send access_log records ASAP or accumulate them and
4596 then write/send them in larger chunks. Buffering may improve
4597 performance because it decreases the number of I/Os. However,
4598 buffering increases the delay before log records become available to
4599 the final recipient (e.g., a disk file or logging daemon) and,
4600 hence, increases the risk of log records loss.
4602 Note that even when buffered_logs are off, Squid may have to buffer
4603 records if it cannot write/send them immediately due to pending I/Os
4604 (e.g., the I/O writing the previous log record) or connectivity loss.
4606 Currently honored by 'daemon' and 'tcp' access_log modules only.
4609 NAME: netdb_filename
4611 DEFAULT: stdio:@DEFAULT_NETDB_FILE@
4612 LOC: Config.netdbFilename
4615 Where Squid stores it's netdb journal.
4616 When enabled this journal preserves netdb state between restarts.
4618 To disable, enter "none".
4622 OPTIONS FOR TROUBLESHOOTING
4623 -----------------------------------------------------------------------------
4628 DEFAULT_IF_NONE: @DEFAULT_CACHE_LOG@
4629 LOC: Debug::cache_log
4631 Squid administrative logging file.
4633 This is where general information about Squid behavior goes. You can
4634 increase the amount of data logged to this file and how often it is
4635 rotated with "debug_options"
4641 DEFAULT_DOC: Log all critical and important messages.
4642 LOC: Debug::debugOptions
4644 Logging options are set as section,level where each source file
4645 is assigned a unique section. Lower levels result in less
4646 output, Full debugging (level 9) can result in a very large
4647 log file, so be careful.
4649 The magic word "ALL" sets debugging levels for all sections.
4650 The default is to run with "ALL,1" to record important warnings.
4652 The rotate=N option can be used to keep more or less of these logs
4653 than would otherwise be kept by logfile_rotate.
4654 For most uses a single log should be enough to monitor current
4655 events affecting Squid.
4660 LOC: Config.coredump_dir
4661 DEFAULT_IF_NONE: none
4662 DEFAULT_DOC: Use the directory from where Squid was started.
4664 By default Squid leaves core files in the directory from where
4665 it was started. If you set 'coredump_dir' to a directory
4666 that exists, Squid will chdir() to that directory at startup
4667 and coredump files will be left there.
4671 # Leave coredumps in the first cache dir
4672 coredump_dir @DEFAULT_SWAP_DIR@
4678 OPTIONS FOR FTP GATEWAYING
4679 -----------------------------------------------------------------------------
4685 LOC: Config.Ftp.anon_user
4687 If you want the anonymous login password to be more informative
4688 (and enable the use of picky FTP servers), set this to something
4689 reasonable for your domain, like wwwuser@somewhere.net
4691 The reason why this is domainless by default is the
4692 request can be made on the behalf of a user in any domain,
4693 depending on how the cache is used.
4694 Some FTP server also validate the email address is valid
4695 (for example perl.com).
4701 LOC: Config.Ftp.passive
4703 If your firewall does not allow Squid to use passive
4704 connections, turn off this option.
4706 Use of ftp_epsv_all option requires this to be ON.
4712 LOC: Config.Ftp.epsv_all
4714 FTP Protocol extensions permit the use of a special "EPSV ALL" command.
4716 NATs may be able to put the connection on a "fast path" through the
4717 translator, as the EPRT command will never be used and therefore,
4718 translation of the data portion of the segments will never be needed.
4720 When a client only expects to do two-way FTP transfers this may be
4722 If squid finds that it must do a three-way FTP transfer after issuing
4723 an EPSV ALL command, the FTP session will fail.
4725 If you have any doubts about this option do not use it.
4726 Squid will nicely attempt all other connection methods.
4728 Requires ftp_passive to be ON (default) for any effect.
4734 LOC: Config.accessList.ftp_epsv
4736 FTP Protocol extensions permit the use of a special "EPSV" command.
4738 NATs may be able to put the connection on a "fast path" through the
4739 translator using EPSV, as the EPRT command will never be used
4740 and therefore, translation of the data portion of the segments
4741 will never be needed.
4743 EPSV is often required to interoperate with FTP servers on IPv6
4744 networks. On the other hand, it may break some IPv4 servers.
4746 By default, EPSV may try EPSV with any FTP server. To fine tune
4747 that decision, you may restrict EPSV to certain clients or servers
4750 ftp_epsv allow|deny al1 acl2 ...
4752 WARNING: Disabling EPSV may cause problems with external NAT and IPv6.
4754 Only fast ACLs are supported.
4755 Requires ftp_passive to be ON (default) for any effect.
4761 LOC: Config.Ftp.eprt
4763 FTP Protocol extensions permit the use of a special "EPRT" command.
4765 This extension provides a protocol neutral alternative to the
4766 IPv4-only PORT command. When supported it enables active FTP data
4767 channels over IPv6 and efficient NAT handling.
4769 Turning this OFF will prevent EPRT being attempted and will skip
4770 straight to using PORT for IPv4 servers.
4772 Some devices are known to not handle this extension correctly and
4773 may result in crashes. Devices which suport EPRT enough to fail
4774 cleanly will result in Squid attempting PORT anyway. This directive
4775 should only be disabled when EPRT results in device failures.
4777 WARNING: Doing so will convert Squid back to the old behavior with all
4778 the related problems with external NAT devices/layers and IPv4-only FTP.
4781 NAME: ftp_sanitycheck
4784 LOC: Config.Ftp.sanitycheck
4786 For security and data integrity reasons Squid by default performs
4787 sanity checks of the addresses of FTP data connections ensure the
4788 data connection is to the requested server. If you need to allow
4789 FTP connections to servers using another IP address for the data
4790 connection turn this off.
4793 NAME: ftp_telnet_protocol
4796 LOC: Config.Ftp.telnet
4798 The FTP protocol is officially defined to use the telnet protocol
4799 as transport channel for the control connection. However, many
4800 implementations are broken and does not respect this aspect of
4803 If you have trouble accessing files with ASCII code 255 in the
4804 path or similar problems involving this ASCII code you can
4805 try setting this directive to off. If that helps, report to the
4806 operator of the FTP server in question that their FTP server
4807 is broken and does not follow the FTP standard.
4811 OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
4812 -----------------------------------------------------------------------------
4817 DEFAULT: @DEFAULT_DISKD@
4818 LOC: Config.Program.diskd
4820 Specify the location of the diskd executable.
4821 Note this is only useful if you have compiled in
4822 diskd as one of the store io modules.
4825 NAME: unlinkd_program
4828 DEFAULT: @DEFAULT_UNLINKD@
4829 LOC: Config.Program.unlinkd
4831 Specify the location of the executable for file deletion process.
4834 NAME: pinger_program
4837 DEFAULT: @DEFAULT_PINGER@
4840 Specify the location of the executable for the pinger process.
4849 Control whether the pinger is active at run-time.
4850 Enables turning ICMP pinger on and off with a simple
4851 squid -k reconfigure.
4856 OPTIONS FOR URL REWRITING
4857 -----------------------------------------------------------------------------
4860 NAME: url_rewrite_program redirect_program
4862 LOC: Config.Program.redirect
4865 Specify the location of the executable URL rewriter to use.
4866 Since they can perform almost any function there isn't one included.
4868 For each requested URL, the rewriter will receive on line with the format
4870 [channel-ID <SP>] URL [<SP> extras]<NL>
4872 See url_rewrite_extras on how to send "extras" with optional values to
4874 After processing the request the helper must reply using the following format:
4876 [channel-ID <SP>] result [<SP> kv-pairs]
4878 The result code can be:
4880 OK status=30N url="..."
4881 Redirect the URL to the one supplied in 'url='.
4882 'status=' is optional and contains the status code to send
4883 the client in Squids HTTP response. It must be one of the
4884 HTTP redirect status codes: 301, 302, 303, 307, 308.
4885 When no status is given Squid will use 302.
4887 OK rewrite-url="..."
4888 Rewrite the URL to the one supplied in 'rewrite-url='.
4889 The new URL is fetched directly by Squid and returned to
4890 the client as the response to its request.
4893 When neither of url= and rewrite-url= are sent Squid does
4897 Do not change the URL.
4900 An internal error occurred in the helper, preventing
4901 a result being identified. The 'message=' key name is
4902 reserved for delivering a log message.
4905 In addition to the above kv-pairs Squid also understands the following
4906 optional kv-pairs received from URL rewriters:
4908 Associates a TAG with the client TCP connection.
4909 The TAG is treated as a regular annotation but persists across
4910 future requests on the client connection rather than just the
4911 current request. A helper may update the TAG during subsequent
4912 requests be returning a new kv-pair.
4914 When using the concurrency= option the protocol is changed by
4915 introducing a query channel tag in front of the request/response.
4916 The query channel tag is a number between 0 and concurrency-1.
4917 This value must be echoed back unchanged to Squid as the first part
4918 of the response relating to its request.
4920 WARNING: URL re-writing ability should be avoided whenever possible.
4921 Use the URL redirect form of response instead.
4923 Re-write creates a difference in the state held by the client
4924 and server. Possibly causing confusion when the server response
4925 contains snippets of its view state. Embeded URLs, response
4926 and content Location headers, etc. are not re-written by this
4929 By default, a URL rewriter is not used.
4932 NAME: url_rewrite_children redirect_children
4933 TYPE: HelperChildConfig
4934 DEFAULT: 20 startup=0 idle=1 concurrency=0
4935 LOC: Config.redirectChildren
4937 The maximum number of redirector processes to spawn. If you limit
4938 it too few Squid will have to wait for them to process a backlog of
4939 URLs, slowing it down. If you allow too many they will use RAM
4940 and other system resources noticably.
4942 The startup= and idle= options allow some measure of skew in your
4947 Sets a minimum of how many processes are to be spawned when Squid
4948 starts or reconfigures. When set to zero the first request will
4949 cause spawning of the first child process to handle it.
4951 Starting too few will cause an initial slowdown in traffic as Squid
4952 attempts to simultaneously spawn enough processes to cope.
4956 Sets a minimum of how many processes Squid is to try and keep available
4957 at all times. When traffic begins to rise above what the existing
4958 processes can handle this many more will be spawned up to the maximum
4959 configured. A minimum setting of 1 is required.
4963 The number of requests each redirector helper can handle in
4964 parallel. Defaults to 0 which indicates the redirector
4965 is a old-style single threaded redirector.
4967 When this directive is set to a value >= 1 then the protocol
4968 used to communicate with the helper is modified to include
4969 an ID in front of the request/response. The ID from the request
4970 must be echoed back with the response to that request.
4974 Sets the maximum number of queued requests.
4975 If the queued requests exceed queue size and redirector_bypass
4976 configuration option is set, then redirector is bypassed. Otherwise, if
4977 overloading persists squid may abort its operation.
4978 The default value is set to 2*numberofchildren.
4981 NAME: url_rewrite_host_header redirect_rewrites_host_header
4984 LOC: Config.onoff.redir_rewrites_host
4986 To preserve same-origin security policies in browsers and
4987 prevent Host: header forgery by redirectors Squid rewrites
4988 any Host: header in redirected requests.
4990 If you are running an accelerator this may not be a wanted
4991 effect of a redirector. This directive enables you disable
4992 Host: alteration in reverse-proxy traffic.
4994 WARNING: Entries are cached on the result of the URL rewriting
4995 process, so be careful if you have domain-virtual hosts.
4997 WARNING: Squid and other software verifies the URL and Host
4998 are matching, so be careful not to relay through other proxies
4999 or inspecting firewalls with this disabled.
5002 NAME: url_rewrite_access redirector_access
5005 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
5006 LOC: Config.accessList.redirector
5008 If defined, this access list specifies which requests are
5009 sent to the redirector processes.
5011 This clause supports both fast and slow acl types.
5012 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5015 NAME: url_rewrite_bypass redirector_bypass
5017 LOC: Config.onoff.redirector_bypass
5020 When this is 'on', a request will not go through the
5021 redirector if all the helpers are busy. If this is 'off'
5022 and the redirector queue grows too large, Squid will exit
5023 with a FATAL error and ask you to increase the number of
5024 redirectors. You should only enable this if the redirectors
5025 are not critical to your caching system. If you use
5026 redirectors for access control, and you enable this option,
5027 users may have access to pages they should not
5028 be allowed to request.
5029 This options sets default queue-size option of the url_rewrite_children
5033 NAME: url_rewrite_extras
5034 TYPE: TokenOrQuotedString
5035 LOC: Config.redirector_extras
5036 DEFAULT: "%>a/%>A %un %>rm myip=%la myport=%lp"
5038 Specifies a string to be append to request line format for the
5039 rewriter helper. "Quoted" format values may contain spaces and
5040 logformat %macros. In theory, any logformat %macro can be used.
5041 In practice, a %macro expands as a dash (-) if the helper request is
5042 sent before the required macro information is available to Squid.
5045 NAME: url_rewrite_timeout
5046 TYPE: UrlHelperTimeout
5047 LOC: Config.onUrlRewriteTimeout
5049 DEFAULT_DOC: Squid waits for the helper response forever
5051 Squid times active requests to redirector. The timeout value and Squid
5052 reaction to a timed out request are configurable using the following
5055 url_rewrite_timeout timeout time-units on_timeout=<action> [response=<quoted-response>]
5057 supported timeout actions:
5058 fail Squid return a ERR_GATEWAY_FAILURE error page
5060 bypass Do not re-write the URL
5062 retry Send the lookup to the helper again
5064 use_configured_response
5065 Use the <quoted-response> as helper response
5069 OPTIONS FOR STORE ID
5070 -----------------------------------------------------------------------------
5073 NAME: store_id_program storeurl_rewrite_program
5075 LOC: Config.Program.store_id
5078 Specify the location of the executable StoreID helper to use.
5079 Since they can perform almost any function there isn't one included.
5081 For each requested URL, the helper will receive one line with the format
5083 [channel-ID <SP>] URL [<SP> extras]<NL>
5086 After processing the request the helper must reply using the following format:
5088 [channel-ID <SP>] result [<SP> kv-pairs]
5090 The result code can be:
5093 Use the StoreID supplied in 'store-id='.
5096 The default is to use HTTP request URL as the store ID.
5099 An internal error occured in the helper, preventing
5100 a result being identified.
5102 In addition to the above kv-pairs Squid also understands the following
5103 optional kv-pairs received from URL rewriters:
5105 Associates a TAG with the client TCP connection.
5106 Please see url_rewrite_program related documentation for this
5109 Helper programs should be prepared to receive and possibly ignore
5110 additional whitespace-separated tokens on each input line.
5112 When using the concurrency= option the protocol is changed by
5113 introducing a query channel tag in front of the request/response.
5114 The query channel tag is a number between 0 and concurrency-1.
5115 This value must be echoed back unchanged to Squid as the first part
5116 of the response relating to its request.
5118 NOTE: when using StoreID refresh_pattern will apply to the StoreID
5119 returned from the helper and not the URL.
5121 WARNING: Wrong StoreID value returned by a careless helper may result
5122 in the wrong cached response returned to the user.
5124 By default, a StoreID helper is not used.
5127 NAME: store_id_extras
5128 TYPE: TokenOrQuotedString
5129 LOC: Config.storeId_extras
5130 DEFAULT: "%>a/%>A %un %>rm myip=%la myport=%lp"
5132 Specifies a string to be append to request line format for the
5133 StoreId helper. "Quoted" format values may contain spaces and
5134 logformat %macros. In theory, any logformat %macro can be used.
5135 In practice, a %macro expands as a dash (-) if the helper request is
5136 sent before the required macro information is available to Squid.
5139 NAME: store_id_children storeurl_rewrite_children
5140 TYPE: HelperChildConfig
5141 DEFAULT: 20 startup=0 idle=1 concurrency=0
5142 LOC: Config.storeIdChildren
5144 The maximum number of StoreID helper processes to spawn. If you limit
5145 it too few Squid will have to wait for them to process a backlog of
5146 requests, slowing it down. If you allow too many they will use RAM
5147 and other system resources noticably.
5149 The startup= and idle= options allow some measure of skew in your
5154 Sets a minimum of how many processes are to be spawned when Squid
5155 starts or reconfigures. When set to zero the first request will
5156 cause spawning of the first child process to handle it.
5158 Starting too few will cause an initial slowdown in traffic as Squid
5159 attempts to simultaneously spawn enough processes to cope.
5163 Sets a minimum of how many processes Squid is to try and keep available
5164 at all times. When traffic begins to rise above what the existing
5165 processes can handle this many more will be spawned up to the maximum
5166 configured. A minimum setting of 1 is required.
5170 The number of requests each storeID helper can handle in
5171 parallel. Defaults to 0 which indicates the helper
5172 is a old-style single threaded program.
5174 When this directive is set to a value >= 1 then the protocol
5175 used to communicate with the helper is modified to include
5176 an ID in front of the request/response. The ID from the request
5177 must be echoed back with the response to that request.
5181 Sets the maximum number of queued requests.
5182 If the queued requests exceed queue size and store_id_bypass
5183 configuration option is set, then storeID helper is bypassed. Otherwise,
5184 if overloading persists squid may abort its operation.
5185 The default value is set to 2*numberofchildren.
5188 NAME: store_id_access storeurl_rewrite_access
5191 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
5192 LOC: Config.accessList.store_id
5194 If defined, this access list specifies which requests are
5195 sent to the StoreID processes. By default all requests
5198 This clause supports both fast and slow acl types.
5199 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5202 NAME: store_id_bypass storeurl_rewrite_bypass
5204 LOC: Config.onoff.store_id_bypass
5207 When this is 'on', a request will not go through the
5208 helper if all helpers are busy. If this is 'off'
5209 and the helper queue grows too large, Squid will exit
5210 with a FATAL error and ask you to increase the number of
5211 helpers. You should only enable this if the helperss
5212 are not critical to your caching system. If you use
5213 helpers for critical caching components, and you enable this
5214 option, users may not get objects from cache.
5215 This options sets default queue-size option of the store_id_children
5220 OPTIONS FOR TUNING THE CACHE
5221 -----------------------------------------------------------------------------
5224 NAME: cache no_cache
5227 DEFAULT_DOC: By default, this directive is unused and has no effect.
5228 LOC: Config.accessList.noCache
5230 Requests denied by this directive will not be served from the cache
5231 and their responses will not be stored in the cache. This directive
5232 has no effect on other transactions and on already cached responses.
5234 This clause supports both fast and slow acl types.
5235 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5237 This and the two other similar caching directives listed below are
5238 checked at different transaction processing stages, have different
5239 access to response information, affect different cache operations,
5240 and differ in slow ACLs support:
5242 * cache: Checked before Squid makes a hit/miss determination.
5243 No access to reply information!
5244 Denies both serving a hit and storing a miss.
5245 Supports both fast and slow ACLs.
5246 * send_hit: Checked after a hit was detected.
5247 Has access to reply (hit) information.
5248 Denies serving a hit only.
5249 Supports fast ACLs only.
5250 * store_miss: Checked before storing a cachable miss.
5251 Has access to reply (miss) information.
5252 Denies storing a miss only.
5253 Supports fast ACLs only.
5255 If you are not sure which of the three directives to use, apply the
5256 following decision logic:
5258 * If your ACL(s) are of slow type _and_ need response info, redesign.
5259 Squid does not support that particular combination at this time.
5261 * If your directive ACL(s) are of slow type, use "cache"; and/or
5262 * if your directive ACL(s) need no response info, use "cache".
5264 * If you do not want the response cached, use store_miss; and/or
5265 * if you do not want a hit on a cached response, use send_hit.
5271 DEFAULT_DOC: By default, this directive is unused and has no effect.
5272 LOC: Config.accessList.sendHit
5274 Responses denied by this directive will not be served from the cache
5275 (but may still be cached, see store_miss). This directive has no
5276 effect on the responses it allows and on the cached objects.
5278 Please see the "cache" directive for a summary of differences among
5279 store_miss, send_hit, and cache directives.
5281 Unlike the "cache" directive, send_hit only supports fast acl
5282 types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5286 # apply custom Store ID mapping to some URLs
5287 acl MapMe dstdomain .c.example.com
5288 store_id_program ...
5289 store_id_access allow MapMe
5291 # but prevent caching of special responses
5292 # such as 302 redirects that cause StoreID loops
5293 acl Ordinary http_status 200-299
5294 store_miss deny MapMe !Ordinary
5296 # and do not serve any previously stored special responses
5297 # from the cache (in case they were already cached before
5298 # the above store_miss rule was in effect).
5299 send_hit deny MapMe !Ordinary
5305 DEFAULT_DOC: By default, this directive is unused and has no effect.
5306 LOC: Config.accessList.storeMiss
5308 Responses denied by this directive will not be cached (but may still
5309 be served from the cache, see send_hit). This directive has no
5310 effect on the responses it allows and on the already cached responses.
5312 Please see the "cache" directive for a summary of differences among
5313 store_miss, send_hit, and cache directives. See the
5314 send_hit directive for a usage example.
5316 Unlike the "cache" directive, store_miss only supports fast acl
5317 types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5323 LOC: Config.maxStale
5326 This option puts an upper limit on how stale content Squid
5327 will serve from the cache if cache validation fails.
5328 Can be overriden by the refresh_pattern max-stale option.
5331 NAME: refresh_pattern
5332 TYPE: refreshpattern
5336 usage: refresh_pattern [-i] regex min percent max [options]
5338 By default, regular expressions are CASE-SENSITIVE. To make
5339 them case-insensitive, use the -i option.
5341 'Min' is the time (in minutes) an object without an explicit
5342 expiry time should be considered fresh. The recommended
5343 value is 0, any higher values may cause dynamic applications
5344 to be erroneously cached unless the application designer
5345 has taken the appropriate actions.
5347 'Percent' is a percentage of the objects age (time since last
5348 modification age) an object without explicit expiry time
5349 will be considered fresh.
5351 'Max' is an upper limit on how long objects without an explicit
5352 expiry time will be considered fresh.
5354 options: override-expire
5364 override-expire enforces min age even if the server
5365 sent an explicit expiry time (e.g., with the
5366 Expires: header or Cache-Control: max-age). Doing this
5367 VIOLATES the HTTP standard. Enabling this feature
5368 could make you liable for problems which it causes.
5370 Note: override-expire does not enforce staleness - it only extends
5371 freshness / min. If the server returns a Expires time which
5372 is longer than your max time, Squid will still consider
5373 the object fresh for that period of time.
5375 override-lastmod enforces min age even on objects
5376 that were modified recently.
5378 reload-into-ims changes a client no-cache or ``reload''
5379 request for a cached entry into a conditional request using
5380 If-Modified-Since and/or If-None-Match headers, provided the
5381 cached entry has a Last-Modified and/or a strong ETag header.
5382 Doing this VIOLATES the HTTP standard. Enabling this feature
5383 could make you liable for problems which it causes.
5385 ignore-reload ignores a client no-cache or ``reload''
5386 header. Doing this VIOLATES the HTTP standard. Enabling
5387 this feature could make you liable for problems which
5390 ignore-no-store ignores any ``Cache-control: no-store''
5391 headers received from a server. Doing this VIOLATES
5392 the HTTP standard. Enabling this feature could make you
5393 liable for problems which it causes.
5395 ignore-private ignores any ``Cache-control: private''
5396 headers received from a server. Doing this VIOLATES
5397 the HTTP standard. Enabling this feature could make you
5398 liable for problems which it causes.
5400 refresh-ims causes squid to contact the origin server
5401 when a client issues an If-Modified-Since request. This
5402 ensures that the client will receive an updated version
5403 if one is available.
5405 store-stale stores responses even if they don't have explicit
5406 freshness or a validator (i.e., Last-Modified or an ETag)
5407 present, or if they're already stale. By default, Squid will
5408 not cache such responses because they usually can't be
5409 reused. Note that such responses will be stale by default.
5411 max-stale=NN provide a maximum staleness factor. Squid won't
5412 serve objects more stale than this even if it failed to
5413 validate the object. Default: use the max_stale global limit.
5415 Basically a cached object is:
5417 FRESH if expire > now, else STALE
5419 FRESH if lm-factor < percent, else STALE
5423 The refresh_pattern lines are checked in the order listed here.
5424 The first entry which matches is used. If none of the entries
5425 match the default will be used.
5427 Note, you must uncomment all the default lines if you want
5428 to change one. The default setting is only active if none is
5434 # Add any of your own refresh_pattern entries above these.
5436 refresh_pattern ^ftp: 1440 20% 10080
5437 refresh_pattern ^gopher: 1440 0% 1440
5438 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0
5439 refresh_pattern . 0 20% 4320
5443 NAME: quick_abort_min
5447 LOC: Config.quickAbort.min
5450 NAME: quick_abort_max
5454 LOC: Config.quickAbort.max
5457 NAME: quick_abort_pct
5461 LOC: Config.quickAbort.pct
5463 The cache by default continues downloading aborted requests
5464 which are almost completed (less than 16 KB remaining). This
5465 may be undesirable on slow (e.g. SLIP) links and/or very busy
5466 caches. Impatient users may tie up file descriptors and
5467 bandwidth by repeatedly requesting and immediately aborting
5470 When the user aborts a request, Squid will check the
5471 quick_abort values to the amount of data transferred until
5474 If the transfer has less than 'quick_abort_min' KB remaining,
5475 it will finish the retrieval.
5477 If the transfer has more than 'quick_abort_max' KB remaining,
5478 it will abort the retrieval.
5480 If more than 'quick_abort_pct' of the transfer has completed,
5481 it will finish the retrieval.
5483 If you do not want any retrieval to continue after the client
5484 has aborted, set both 'quick_abort_min' and 'quick_abort_max'
5487 If you want retrievals to always continue if they are being
5488 cached set 'quick_abort_min' to '-1 KB'.
5491 NAME: read_ahead_gap
5492 COMMENT: buffer-size
5494 LOC: Config.readAheadGap
5497 The amount of data the cache will buffer ahead of what has been
5498 sent to the client when retrieving an object from another server.
5502 IFDEF: USE_HTTP_VIOLATIONS
5505 LOC: Config.negativeTtl
5508 Set the Default Time-to-Live (TTL) for failed requests.
5509 Certain types of failures (such as "connection refused" and
5510 "404 Not Found") are able to be negatively-cached for a short time.
5511 Modern web servers should provide Expires: header, however if they
5512 do not this can provide a minimum TTL.
5513 The default is not to cache errors with unknown expiry details.
5515 Note that this is different from negative caching of DNS lookups.
5517 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5518 this feature could make you liable for problems which it
5522 NAME: positive_dns_ttl
5525 LOC: Config.positiveDnsTtl
5528 Upper limit on how long Squid will cache positive DNS responses.
5529 Default is 6 hours (360 minutes). This directive must be set
5530 larger than negative_dns_ttl.
5533 NAME: negative_dns_ttl
5536 LOC: Config.negativeDnsTtl
5539 Time-to-Live (TTL) for negative caching of failed DNS lookups.
5540 This also sets the lower cache limit on positive lookups.
5541 Minimum value is 1 second, and it is not recommendable to go
5542 much below 10 seconds.
5545 NAME: range_offset_limit
5546 COMMENT: size [acl acl...]
5548 LOC: Config.rangeOffsetLimit
5551 usage: (size) [units] [[!]aclname]
5553 Sets an upper limit on how far (number of bytes) into the file
5554 a Range request may be to cause Squid to prefetch the whole file.
5555 If beyond this limit, Squid forwards the Range request as it is and
5556 the result is NOT cached.
5558 This is to stop a far ahead range request (lets say start at 17MB)
5559 from making Squid fetch the whole object up to that point before
5560 sending anything to the client.
5562 Multiple range_offset_limit lines may be specified, and they will
5563 be searched from top to bottom on each request until a match is found.
5564 The first match found will be used. If no line matches a request, the
5565 default limit of 0 bytes will be used.
5567 'size' is the limit specified as a number of units.
5569 'units' specifies whether to use bytes, KB, MB, etc.
5570 If no units are specified bytes are assumed.
5572 A size of 0 causes Squid to never fetch more than the
5573 client requested. (default)
5575 A size of 'none' causes Squid to always fetch the object from the
5576 beginning so it may cache the result. (2.0 style)
5578 'aclname' is the name of a defined ACL.
5580 NP: Using 'none' as the byte value here will override any quick_abort settings
5581 that may otherwise apply to the range request. The range request will
5582 be fully fetched from start to finish regardless of the client
5583 actions. This affects bandwidth usage.
5586 NAME: minimum_expiry_time
5589 LOC: Config.minimum_expiry_time
5592 The minimum caching time according to (Expires - Date)
5593 headers Squid honors if the object can't be revalidated.
5594 The default is 60 seconds.
5596 In reverse proxy environments it might be desirable to honor
5597 shorter object lifetimes. It is most likely better to make
5598 your server return a meaningful Last-Modified header however.
5600 In ESI environments where page fragments often have short
5601 lifetimes, this will often be best set to 0.
5604 NAME: store_avg_object_size
5608 LOC: Config.Store.avgObjectSize
5610 Average object size, used to estimate number of objects your
5611 cache can hold. The default is 13 KB.
5613 This is used to pre-seed the cache index memory allocation to
5614 reduce expensive reallocate operations while handling clients
5615 traffic. Too-large values may result in memory allocation during
5616 peak traffic, too-small values will result in wasted memory.
5618 Check the cache manager 'info' report metrics for the real
5619 object sizes seen by your Squid before tuning this.
5622 NAME: store_objects_per_bucket
5625 LOC: Config.Store.objectsPerBucket
5627 Target number of objects per bucket in the store hash table.
5628 Lowering this value increases the total number of buckets and
5629 also the storage maintenance rate. The default is 20.
5634 -----------------------------------------------------------------------------
5637 NAME: request_header_max_size
5641 LOC: Config.maxRequestHeaderSize
5643 This specifies the maximum size for HTTP headers in a request.
5644 Request headers are usually relatively small (about 512 bytes).
5645 Placing a limit on the request header size will catch certain
5646 bugs (for example with persistent connections) and possibly
5647 buffer-overflow or denial-of-service attacks.
5650 NAME: reply_header_max_size
5654 LOC: Config.maxReplyHeaderSize
5656 This specifies the maximum size for HTTP headers in a reply.
5657 Reply headers are usually relatively small (about 512 bytes).
5658 Placing a limit on the reply header size will catch certain
5659 bugs (for example with persistent connections) and possibly
5660 buffer-overflow or denial-of-service attacks.
5663 NAME: request_body_max_size
5667 DEFAULT_DOC: No limit.
5668 LOC: Config.maxRequestBodySize
5670 This specifies the maximum size for an HTTP request body.
5671 In other words, the maximum size of a PUT/POST request.
5672 A user who attempts to send a request with a body larger
5673 than this limit receives an "Invalid Request" error message.
5674 If you set this parameter to a zero (the default), there will
5675 be no limit imposed.
5677 See also client_request_buffer_max_size for an alternative
5678 limitation on client uploads which can be configured.
5681 NAME: client_request_buffer_max_size
5685 LOC: Config.maxRequestBufferSize
5687 This specifies the maximum buffer size of a client request.
5688 It prevents squid eating too much memory when somebody uploads
5693 IFDEF: USE_HTTP_VIOLATIONS
5696 DEFAULT_DOC: Obey RFC 2616.
5697 LOC: Config.accessList.brokenPosts
5699 A list of ACL elements which, if matched, causes Squid to send
5700 an extra CRLF pair after the body of a PUT/POST request.
5702 Some HTTP servers has broken implementations of PUT/POST,
5703 and rely on an extra CRLF pair sent by some WWW clients.
5705 Quote from RFC2616 section 4.1 on this matter:
5707 Note: certain buggy HTTP/1.0 client implementations generate an
5708 extra CRLF's after a POST request. To restate what is explicitly
5709 forbidden by the BNF, an HTTP/1.1 client must not preface or follow
5710 a request with an extra CRLF.
5712 This clause only supports fast acl types.
5713 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5716 acl buggy_server url_regex ^http://....
5717 broken_posts allow buggy_server
5720 NAME: adaptation_uses_indirect_client icap_uses_indirect_client
5723 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_ADAPTATION
5725 LOC: Adaptation::Config::use_indirect_client
5727 Controls whether the indirect client IP address (instead of the direct
5728 client IP address) is passed to adaptation services.
5730 See also: follow_x_forwarded_for adaptation_send_client_ip
5734 IFDEF: USE_HTTP_VIOLATIONS
5738 LOC: Config.onoff.via
5740 If set (default), Squid will include a Via header in requests and
5741 replies as required by RFC2616.
5747 LOC: Config.onoff.ie_refresh
5750 Microsoft Internet Explorer up until version 5.5 Service
5751 Pack 1 has an issue with transparent proxies, wherein it
5752 is impossible to force a refresh. Turning this on provides
5753 a partial fix to the problem, by causing all IMS-REFRESH
5754 requests from older IE versions to check the origin server
5755 for fresh content. This reduces hit ratio by some amount
5756 (~10% in my experience), but allows users to actually get
5757 fresh content when they want it. Note because Squid
5758 cannot tell if the user is using 5.5 or 5.5SP1, the behavior
5759 of 5.5 is unchanged from old versions of Squid (i.e. a
5760 forced refresh is impossible). Newer versions of IE will,
5761 hopefully, continue to have the new behavior and will be
5762 handled based on that assumption. This option defaults to
5763 the old Squid behavior, which is better for hit ratios but
5764 worse for clients using IE, if they need to be able to
5765 force fresh content.
5768 NAME: vary_ignore_expire
5771 LOC: Config.onoff.vary_ignore_expire
5774 Many HTTP servers supporting Vary gives such objects
5775 immediate expiry time with no cache-control header
5776 when requested by a HTTP/1.0 client. This option
5777 enables Squid to ignore such expiry times until
5778 HTTP/1.1 is fully implemented.
5780 WARNING: If turned on this may eventually cause some
5781 varying objects not intended for caching to get cached.
5784 NAME: request_entities
5786 LOC: Config.onoff.request_entities
5789 Squid defaults to deny GET and HEAD requests with request entities,
5790 as the meaning of such requests are undefined in the HTTP standard
5791 even if not explicitly forbidden.
5793 Set this directive to on if you have clients which insists
5794 on sending request entities in GET or HEAD requests. But be warned
5795 that there is server software (both proxies and web servers) which
5796 can fail to properly process this kind of request which may make you
5797 vulnerable to cache pollution attacks if enabled.
5800 NAME: request_header_access
5801 IFDEF: USE_HTTP_VIOLATIONS
5802 TYPE: http_header_access
5803 LOC: Config.request_header_access
5805 DEFAULT_DOC: No limits.
5807 Usage: request_header_access header_name allow|deny [!]aclname ...
5809 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5810 this feature could make you liable for problems which it
5813 This option replaces the old 'anonymize_headers' and the
5814 older 'http_anonymizer' option with something that is much
5815 more configurable. A list of ACLs for each header name allows
5816 removal of specific header fields under specific conditions.
5818 This option only applies to outgoing HTTP request headers (i.e.,
5819 headers sent by Squid to the next HTTP hop such as a cache peer
5820 or an origin server). The option has no effect during cache hit
5821 detection. The equivalent adaptation vectoring point in ICAP
5822 terminology is post-cache REQMOD.
5824 The option is applied to individual outgoing request header
5825 fields. For each request header field F, Squid uses the first
5826 qualifying sets of request_header_access rules:
5828 1. Rules with header_name equal to F's name.
5829 2. Rules with header_name 'Other', provided F's name is not
5830 on the hard-coded list of commonly used HTTP header names.
5831 3. Rules with header_name 'All'.
5833 Within that qualifying rule set, rule ACLs are checked as usual.
5834 If ACLs of an "allow" rule match, the header field is allowed to
5835 go through as is. If ACLs of a "deny" rule match, the header is
5836 removed and request_header_replace is then checked to identify
5837 if the removed header has a replacement. If no rules within the
5838 set have matching ACLs, the header field is left as is.
5840 For example, to achieve the same behavior as the old
5841 'http_anonymizer standard' option, you should use:
5843 request_header_access From deny all
5844 request_header_access Referer deny all
5845 request_header_access User-Agent deny all
5847 Or, to reproduce the old 'http_anonymizer paranoid' feature
5850 request_header_access Authorization allow all
5851 request_header_access Proxy-Authorization allow all
5852 request_header_access Cache-Control allow all
5853 request_header_access Content-Length allow all
5854 request_header_access Content-Type allow all
5855 request_header_access Date allow all
5856 request_header_access Host allow all
5857 request_header_access If-Modified-Since allow all
5858 request_header_access Pragma allow all
5859 request_header_access Accept allow all
5860 request_header_access Accept-Charset allow all
5861 request_header_access Accept-Encoding allow all
5862 request_header_access Accept-Language allow all
5863 request_header_access Connection allow all
5864 request_header_access All deny all
5866 HTTP reply headers are controlled with the reply_header_access directive.
5868 By default, all headers are allowed (no anonymizing is performed).
5871 NAME: reply_header_access
5872 IFDEF: USE_HTTP_VIOLATIONS
5873 TYPE: http_header_access
5874 LOC: Config.reply_header_access
5876 DEFAULT_DOC: No limits.
5878 Usage: reply_header_access header_name allow|deny [!]aclname ...
5880 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5881 this feature could make you liable for problems which it
5884 This option only applies to reply headers, i.e., from the
5885 server to the client.
5887 This is the same as request_header_access, but in the other
5888 direction. Please see request_header_access for detailed
5891 For example, to achieve the same behavior as the old
5892 'http_anonymizer standard' option, you should use:
5894 reply_header_access Server deny all
5895 reply_header_access WWW-Authenticate deny all
5896 reply_header_access Link deny all
5898 Or, to reproduce the old 'http_anonymizer paranoid' feature
5901 reply_header_access Allow allow all
5902 reply_header_access WWW-Authenticate allow all
5903 reply_header_access Proxy-Authenticate allow all
5904 reply_header_access Cache-Control allow all
5905 reply_header_access Content-Encoding allow all
5906 reply_header_access Content-Length allow all
5907 reply_header_access Content-Type allow all
5908 reply_header_access Date allow all
5909 reply_header_access Expires allow all
5910 reply_header_access Last-Modified allow all
5911 reply_header_access Location allow all
5912 reply_header_access Pragma allow all
5913 reply_header_access Content-Language allow all
5914 reply_header_access Retry-After allow all
5915 reply_header_access Title allow all
5916 reply_header_access Content-Disposition allow all
5917 reply_header_access Connection allow all
5918 reply_header_access All deny all
5920 HTTP request headers are controlled with the request_header_access directive.
5922 By default, all headers are allowed (no anonymizing is
5926 NAME: request_header_replace header_replace
5927 IFDEF: USE_HTTP_VIOLATIONS
5928 TYPE: http_header_replace
5929 LOC: Config.request_header_access
5932 Usage: request_header_replace header_name message
5933 Example: request_header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
5935 This option allows you to change the contents of headers
5936 denied with request_header_access above, by replacing them
5937 with some fixed string.
5939 This only applies to request headers, not reply headers.
5941 By default, headers are removed if denied.
5944 NAME: reply_header_replace
5945 IFDEF: USE_HTTP_VIOLATIONS
5946 TYPE: http_header_replace
5947 LOC: Config.reply_header_access
5950 Usage: reply_header_replace header_name message
5951 Example: reply_header_replace Server Foo/1.0
5953 This option allows you to change the contents of headers
5954 denied with reply_header_access above, by replacing them
5955 with some fixed string.
5957 This only applies to reply headers, not request headers.
5959 By default, headers are removed if denied.
5962 NAME: request_header_add
5963 TYPE: HeaderWithAclList
5964 LOC: Config.request_header_add
5967 Usage: request_header_add field-name field-value acl1 [acl2] ...
5968 Example: request_header_add X-Client-CA "CA=%ssl::>cert_issuer" all
5970 This option adds header fields to outgoing HTTP requests (i.e.,
5971 request headers sent by Squid to the next HTTP hop such as a
5972 cache peer or an origin server). The option has no effect during
5973 cache hit detection. The equivalent adaptation vectoring point
5974 in ICAP terminology is post-cache REQMOD.
5976 Field-name is a token specifying an HTTP header name. If a
5977 standard HTTP header name is used, Squid does not check whether
5978 the new header conflicts with any existing headers or violates
5979 HTTP rules. If the request to be modified already contains a
5980 field with the same name, the old field is preserved but the
5981 header field values are not merged.
5983 Field-value is either a token or a quoted string. If quoted
5984 string format is used, then the surrounding quotes are removed
5985 while escape sequences and %macros are processed.
5987 In theory, all of the logformat codes can be used as %macros.
5988 However, unlike logging (which happens at the very end of
5989 transaction lifetime), the transaction may not yet have enough
5990 information to expand a macro when the new header value is needed.
5991 And some information may already be available to Squid but not yet
5992 committed where the macro expansion code can access it (report
5993 such instances!). The macro will be expanded into a single dash
5994 ('-') in such cases. Not all macros have been tested.
5996 One or more Squid ACLs may be specified to restrict header
5997 injection to matching requests. As always in squid.conf, all
5998 ACLs in an option ACL list must be satisfied for the insertion
5999 to happen. The request_header_add option supports fast ACLs
6008 This option used to log custom information about the master
6009 transaction. For example, an admin may configure Squid to log
6010 which "user group" the transaction belongs to, where "user group"
6011 will be determined based on a set of ACLs and not [just]
6012 authentication information.
6013 Values of key/value pairs can be logged using %{key}note macros:
6015 note key value acl ...
6016 logformat myFormat ... %{key}note ...
6019 NAME: relaxed_header_parser
6020 COMMENT: on|off|warn
6022 LOC: Config.onoff.relaxed_header_parser
6025 In the default "on" setting Squid accepts certain forms
6026 of non-compliant HTTP messages where it is unambiguous
6027 what the sending application intended even if the message
6028 is not correctly formatted. The messages is then normalized
6029 to the correct form when forwarded by Squid.
6031 If set to "warn" then a warning will be emitted in cache.log
6032 each time such HTTP error is encountered.
6034 If set to "off" then such HTTP errors will cause the request
6035 or response to be rejected.
6038 NAME: collapsed_forwarding
6041 LOC: Config.onoff.collapsed_forwarding
6044 This option controls whether Squid is allowed to merge multiple
6045 potentially cachable requests for the same URI before Squid knows
6046 whether the response is going to be cachable.
6048 This feature is disabled by default: Enabling collapsed forwarding
6049 needlessly delays forwarding requests that look cachable (when they are
6050 collapsed) but then need to be forwarded individually anyway because
6051 they end up being for uncachable content. However, in some cases, such
6052 as accelleration of highly cachable content with periodic or groupped
6053 expiration times, the gains from collapsing [large volumes of
6054 simultenous refresh requests] outweigh losses from such delays.
6059 -----------------------------------------------------------------------------
6062 NAME: forward_timeout
6065 LOC: Config.Timeout.forward
6068 This parameter specifies how long Squid should at most attempt in
6069 finding a forwarding path for the request before giving up.
6072 NAME: connect_timeout
6075 LOC: Config.Timeout.connect
6078 This parameter specifies how long to wait for the TCP connect to
6079 the requested server or peer to complete before Squid should
6080 attempt to find another path where to forward the request.
6083 NAME: peer_connect_timeout
6086 LOC: Config.Timeout.peer_connect
6089 This parameter specifies how long to wait for a pending TCP
6090 connection to a peer cache. The default is 30 seconds. You
6091 may also set different timeout values for individual neighbors
6092 with the 'connect-timeout' option on a 'cache_peer' line.
6098 LOC: Config.Timeout.read
6101 Applied on peer server connections.
6103 After each successful read(), the timeout will be extended by this
6104 amount. If no data is read again after this amount of time,
6105 the request is aborted and logged with ERR_READ_TIMEOUT.
6107 The default is 15 minutes.
6113 LOC: Config.Timeout.write
6116 This timeout is tracked for all connections that have data
6117 available for writing and are waiting for the socket to become
6118 ready. After each successful write, the timeout is extended by
6119 the configured amount. If Squid has data to write but the
6120 connection is not ready for the configured duration, the
6121 transaction associated with the connection is terminated. The
6122 default is 15 minutes.
6125 NAME: request_timeout
6127 LOC: Config.Timeout.request
6130 How long to wait for complete HTTP request headers after initial
6131 connection establishment.
6134 NAME: request_start_timeout
6136 LOC: Config.Timeout.request_start_timeout
6139 How long to wait for the first request byte after initial
6140 connection establishment.
6143 NAME: client_idle_pconn_timeout persistent_request_timeout
6145 LOC: Config.Timeout.clientIdlePconn
6148 How long to wait for the next HTTP request on a persistent
6149 client connection after the previous request completes.
6152 NAME: ftp_client_idle_timeout
6154 LOC: Config.Timeout.ftpClientIdle
6157 How long to wait for an FTP request on a connection to Squid ftp_port.
6158 Many FTP clients do not deal with idle connection closures well,
6159 necessitating a longer default timeout than client_idle_pconn_timeout
6160 used for incoming HTTP requests.
6163 NAME: client_lifetime
6166 LOC: Config.Timeout.lifetime
6169 The maximum amount of time a client (browser) is allowed to
6170 remain connected to the cache process. This protects the Cache
6171 from having a lot of sockets (and hence file descriptors) tied up
6172 in a CLOSE_WAIT state from remote clients that go away without
6173 properly shutting down (either because of a network failure or
6174 because of a poor client implementation). The default is one
6177 NOTE: The default value is intended to be much larger than any
6178 client would ever need to be connected to your cache. You
6179 should probably change client_lifetime only as a last resort.
6180 If you seem to have many client connections tying up
6181 filedescriptors, we recommend first tuning the read_timeout,
6182 request_timeout, persistent_request_timeout and quick_abort values.
6185 NAME: pconn_lifetime
6188 LOC: Config.Timeout.pconnLifetime
6191 Desired maximum lifetime of a persistent connection.
6192 When set, Squid will close a now-idle persistent connection that
6193 exceeded configured lifetime instead of moving the connection into
6194 the idle connection pool (or equivalent). No effect on ongoing/active
6195 transactions. Connection lifetime is the time period from the
6196 connection acceptance or opening time until "now".
6198 This limit is useful in environments with long-lived connections
6199 where Squid configuration or environmental factors change during a
6200 single connection lifetime. If unrestricted, some connections may
6201 last for hours and even days, ignoring those changes that should
6202 have affected their behavior or their existence.
6204 Currently, a new lifetime value supplied via Squid reconfiguration
6205 has no effect on already idle connections unless they become busy.
6207 When set to '0' this limit is not used.
6210 NAME: half_closed_clients
6212 LOC: Config.onoff.half_closed_clients
6215 Some clients may shutdown the sending side of their TCP
6216 connections, while leaving their receiving sides open. Sometimes,
6217 Squid can not tell the difference between a half-closed and a
6218 fully-closed TCP connection.
6220 By default, Squid will immediately close client connections when
6221 read(2) returns "no more data to read."
6223 Change this option to 'on' and Squid will keep open connections
6224 until a read(2) or write(2) on the socket returns an error.
6225 This may show some benefits for reverse proxies. But if not
6226 it is recommended to leave OFF.
6229 NAME: server_idle_pconn_timeout pconn_timeout
6231 LOC: Config.Timeout.serverIdlePconn
6234 Timeout for idle persistent connections to servers and other
6241 LOC: Ident::TheConfig.timeout
6244 Maximum time to wait for IDENT lookups to complete.
6246 If this is too high, and you enabled IDENT lookups from untrusted
6247 users, you might be susceptible to denial-of-service by having
6248 many ident requests going at once.
6251 NAME: shutdown_lifetime
6254 LOC: Config.shutdownLifetime
6257 When SIGTERM or SIGHUP is received, the cache is put into
6258 "shutdown pending" mode until all active sockets are closed.
6259 This value is the lifetime to set for all open descriptors
6260 during shutdown mode. Any active clients after this many
6261 seconds will receive a 'timeout' message.
6265 ADMINISTRATIVE PARAMETERS
6266 -----------------------------------------------------------------------------
6272 LOC: Config.adminEmail
6274 Email-address of local cache manager who will receive
6275 mail if the cache dies. The default is "webmaster".
6281 LOC: Config.EmailFrom
6283 From: email-address for mail sent when the cache dies.
6284 The default is to use 'squid@unique_hostname'.
6286 See also: unique_hostname directive.
6292 LOC: Config.EmailProgram
6294 Email program used to send mail if the cache dies.
6295 The default is "mail". The specified program must comply
6296 with the standard Unix mail syntax:
6297 mail-program recipient < mailfile
6299 Optional command line options can be specified.
6302 NAME: cache_effective_user
6304 DEFAULT: @DEFAULT_CACHE_EFFECTIVE_USER@
6305 LOC: Config.effectiveUser
6307 If you start Squid as root, it will change its effective/real
6308 UID/GID to the user specified below. The default is to change
6309 to UID of @DEFAULT_CACHE_EFFECTIVE_USER@.
6310 see also; cache_effective_group
6313 NAME: cache_effective_group
6316 DEFAULT_DOC: Use system group memberships of the cache_effective_user account
6317 LOC: Config.effectiveGroup
6319 Squid sets the GID to the effective user's default group ID
6320 (taken from the password file) and supplementary group list
6321 from the groups membership.
6323 If you want Squid to run with a specific GID regardless of
6324 the group memberships of the effective user then set this
6325 to the group (or GID) you want Squid to run as. When set
6326 all other group privileges of the effective user are ignored
6327 and only this GID is effective. If Squid is not started as
6328 root the user starting Squid MUST be member of the specified
6331 This option is not recommended by the Squid Team.
6332 Our preference is for administrators to configure a secure
6333 user account for squid with UID/GID matching system policies.
6336 NAME: httpd_suppress_version_string
6340 LOC: Config.onoff.httpd_suppress_version_string
6342 Suppress Squid version string info in HTTP headers and HTML error pages.
6345 NAME: visible_hostname
6347 LOC: Config.visibleHostname
6349 DEFAULT_DOC: Automatically detect the system host name
6351 If you want to present a special hostname in error messages, etc,
6352 define this. Otherwise, the return value of gethostname()
6353 will be used. If you have multiple caches in a cluster and
6354 get errors about IP-forwarding you must set them to have individual
6355 names with this setting.
6358 NAME: unique_hostname
6360 LOC: Config.uniqueHostname
6362 DEFAULT_DOC: Copy the value from visible_hostname
6364 If you want to have multiple machines with the same
6365 'visible_hostname' you must give each machine a different
6366 'unique_hostname' so forwarding loops can be detected.
6369 NAME: hostname_aliases
6371 LOC: Config.hostnameAliases
6374 A list of other DNS names your cache has.
6382 Minimum umask which should be enforced while the proxy
6383 is running, in addition to the umask set at startup.
6385 For a traditional octal representation of umasks, start
6390 OPTIONS FOR THE CACHE REGISTRATION SERVICE
6391 -----------------------------------------------------------------------------
6393 This section contains parameters for the (optional) cache
6394 announcement service. This service is provided to help
6395 cache administrators locate one another in order to join or
6396 create cache hierarchies.
6398 An 'announcement' message is sent (via UDP) to the registration
6399 service by Squid. By default, the announcement message is NOT
6400 SENT unless you enable it with 'announce_period' below.
6402 The announcement message includes your hostname, plus the
6403 following information from this configuration file:
6409 All current information is processed regularly and made
6410 available on the Web at http://www.ircache.net/Cache/Tracker/.
6413 NAME: announce_period
6415 LOC: Config.Announce.period
6417 DEFAULT_DOC: Announcement messages disabled.
6419 This is how frequently to send cache announcements.
6421 To enable announcing your cache, just set an announce period.
6424 announce_period 1 day
6429 DEFAULT: tracker.ircache.net
6430 LOC: Config.Announce.host
6432 Set the hostname where announce registration messages will be sent.
6434 See also announce_port and announce_file
6440 LOC: Config.Announce.file
6442 The contents of this file will be included in the announce
6443 registration messages.
6449 LOC: Config.Announce.port
6451 Set the port where announce registration messages will be sent.
6453 See also announce_host and announce_file
6457 HTTPD-ACCELERATOR OPTIONS
6458 -----------------------------------------------------------------------------
6461 NAME: httpd_accel_surrogate_id
6464 DEFAULT_DOC: visible_hostname is used if no specific ID is set.
6465 LOC: Config.Accel.surrogate_id
6467 Surrogates (http://www.esi.org/architecture_spec_1.0.html)
6468 need an identification token to allow control targeting. Because
6469 a farm of surrogates may all perform the same tasks, they may share
6470 an identification token.
6473 NAME: http_accel_surrogate_remote
6477 LOC: Config.onoff.surrogate_is_remote
6479 Remote surrogates (such as those in a CDN) honour the header
6480 "Surrogate-Control: no-store-remote".
6482 Set this to on to have squid behave as a remote surrogate.
6486 IFDEF: USE_SQUID_ESI
6487 COMMENT: libxml2|expat|custom
6489 LOC: ESIParser::Type
6492 ESI markup is not strictly XML compatible. The custom ESI parser
6493 will give higher performance, but cannot handle non ASCII character
6498 DELAY POOL PARAMETERS
6499 -----------------------------------------------------------------------------
6503 TYPE: delay_pool_count
6505 IFDEF: USE_DELAY_POOLS
6508 This represents the number of delay pools to be used. For example,
6509 if you have one class 2 delay pool and one class 3 delays pool, you
6510 have a total of 2 delay pools.
6512 See also delay_parameters, delay_class, delay_access for pool
6513 configuration details.
6517 TYPE: delay_pool_class
6519 IFDEF: USE_DELAY_POOLS
6522 This defines the class of each delay pool. There must be exactly one
6523 delay_class line for each delay pool. For example, to define two
6524 delay pools, one of class 2 and one of class 3, the settings above
6528 delay_pools 4 # 4 delay pools
6529 delay_class 1 2 # pool 1 is a class 2 pool
6530 delay_class 2 3 # pool 2 is a class 3 pool
6531 delay_class 3 4 # pool 3 is a class 4 pool
6532 delay_class 4 5 # pool 4 is a class 5 pool
6534 The delay pool classes are:
6536 class 1 Everything is limited by a single aggregate
6539 class 2 Everything is limited by a single aggregate
6540 bucket as well as an "individual" bucket chosen
6541 from bits 25 through 32 of the IPv4 address.
6543 class 3 Everything is limited by a single aggregate
6544 bucket as well as a "network" bucket chosen
6545 from bits 17 through 24 of the IP address and a
6546 "individual" bucket chosen from bits 17 through
6547 32 of the IPv4 address.
6549 class 4 Everything in a class 3 delay pool, with an
6550 additional limit on a per user basis. This
6551 only takes effect if the username is established
6552 in advance - by forcing authentication in your
6555 class 5 Requests are grouped according their tag (see
6556 external_acl's tag= reply).
6559 Each pool also requires a delay_parameters directive to configure the pool size
6560 and speed limits used whenever the pool is applied to a request. Along with
6561 a set of delay_access directives to determine when it is used.
6563 NOTE: If an IP address is a.b.c.d
6564 -> bits 25 through 32 are "d"
6565 -> bits 17 through 24 are "c"
6566 -> bits 17 through 32 are "c * 256 + d"
6568 NOTE-2: Due to the use of bitmasks in class 2,3,4 pools they only apply to
6569 IPv4 traffic. Class 1 and 5 pools may be used with IPv6 traffic.
6571 This clause only supports fast acl types.
6572 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6574 See also delay_parameters and delay_access.
6578 TYPE: delay_pool_access
6580 DEFAULT_DOC: Deny using the pool, unless allow rules exist in squid.conf for the pool.
6581 IFDEF: USE_DELAY_POOLS
6584 This is used to determine which delay pool a request falls into.
6586 delay_access is sorted per pool and the matching starts with pool 1,
6587 then pool 2, ..., and finally pool N. The first delay pool where the
6588 request is allowed is selected for the request. If it does not allow
6589 the request to any pool then the request is not delayed (default).
6591 For example, if you want some_big_clients in delay
6592 pool 1 and lotsa_little_clients in delay pool 2:
6594 delay_access 1 allow some_big_clients
6595 delay_access 1 deny all
6596 delay_access 2 allow lotsa_little_clients
6597 delay_access 2 deny all
6598 delay_access 3 allow authenticated_clients
6600 See also delay_parameters and delay_class.
6604 NAME: delay_parameters
6605 TYPE: delay_pool_rates
6607 IFDEF: USE_DELAY_POOLS
6610 This defines the parameters for a delay pool. Each delay pool has
6611 a number of "buckets" associated with it, as explained in the
6612 description of delay_class.
6614 For a class 1 delay pool, the syntax is:
6616 delay_parameters pool aggregate
6618 For a class 2 delay pool:
6620 delay_parameters pool aggregate individual
6622 For a class 3 delay pool:
6624 delay_parameters pool aggregate network individual
6626 For a class 4 delay pool:
6628 delay_parameters pool aggregate network individual user
6630 For a class 5 delay pool:
6632 delay_parameters pool tagrate
6634 The option variables are:
6636 pool a pool number - ie, a number between 1 and the
6637 number specified in delay_pools as used in
6640 aggregate the speed limit parameters for the aggregate bucket
6643 individual the speed limit parameters for the individual
6644 buckets (class 2, 3).
6646 network the speed limit parameters for the network buckets
6649 user the speed limit parameters for the user buckets
6652 tagrate the speed limit parameters for the tag buckets
6655 A pair of delay parameters is written restore/maximum, where restore is
6656 the number of bytes (not bits - modem and network speeds are usually
6657 quoted in bits) per second placed into the bucket, and maximum is the
6658 maximum number of bytes which can be in the bucket at any time.
6660 There must be one delay_parameters line for each delay pool.
6663 For example, if delay pool number 1 is a class 2 delay pool as in the
6664 above example, and is being used to strictly limit each host to 64Kbit/sec
6665 (plus overheads), with no overall limit, the line is:
6667 delay_parameters 1 none 8000/8000
6669 Note that 8 x 8000 KByte/sec -> 64Kbit/sec.
6671 Note that the word 'none' is used to represent no limit.
6674 And, if delay pool number 2 is a class 3 delay pool as in the above
6675 example, and you want to limit it to a total of 256Kbit/sec (strict limit)
6676 with each 8-bit network permitted 64Kbit/sec (strict limit) and each
6677 individual host permitted 4800bit/sec with a bucket maximum size of 64Kbits
6678 to permit a decent web page to be downloaded at a decent speed
6679 (if the network is not being limited due to overuse) but slow down
6680 large downloads more significantly:
6682 delay_parameters 2 32000/32000 8000/8000 600/8000
6684 Note that 8 x 32000 KByte/sec -> 256Kbit/sec.
6685 8 x 8000 KByte/sec -> 64Kbit/sec.
6686 8 x 600 Byte/sec -> 4800bit/sec.
6689 Finally, for a class 4 delay pool as in the example - each user will
6690 be limited to 128Kbits/sec no matter how many workstations they are logged into.:
6692 delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000
6695 See also delay_class and delay_access.
6699 NAME: delay_initial_bucket_level
6700 COMMENT: (percent, 0-100)
6703 IFDEF: USE_DELAY_POOLS
6704 LOC: Config.Delay.initial
6706 The initial bucket percentage is used to determine how much is put
6707 in each bucket when squid starts, is reconfigured, or first notices
6708 a host accessing it (in class 2 and class 3, individual hosts and
6709 networks only have buckets associated with them once they have been
6714 CLIENT DELAY POOL PARAMETERS
6715 -----------------------------------------------------------------------------
6718 NAME: client_delay_pools
6719 TYPE: client_delay_pool_count
6721 IFDEF: USE_DELAY_POOLS
6722 LOC: Config.ClientDelay
6724 This option specifies the number of client delay pools used. It must
6725 preceed other client_delay_* options.
6728 client_delay_pools 2
6730 See also client_delay_parameters and client_delay_access.
6733 NAME: client_delay_initial_bucket_level
6734 COMMENT: (percent, 0-no_limit)
6737 IFDEF: USE_DELAY_POOLS
6738 LOC: Config.ClientDelay.initial
6740 This option determines the initial bucket size as a percentage of
6741 max_bucket_size from client_delay_parameters. Buckets are created
6742 at the time of the "first" connection from the matching IP. Idle
6743 buckets are periodically deleted up.
6745 You can specify more than 100 percent but note that such "oversized"
6746 buckets are not refilled until their size goes down to max_bucket_size
6747 from client_delay_parameters.
6750 client_delay_initial_bucket_level 50
6753 NAME: client_delay_parameters
6754 TYPE: client_delay_pool_rates
6756 IFDEF: USE_DELAY_POOLS
6757 LOC: Config.ClientDelay
6760 This option configures client-side bandwidth limits using the
6763 client_delay_parameters pool speed_limit max_bucket_size
6765 pool is an integer ID used for client_delay_access matching.
6767 speed_limit is bytes added to the bucket per second.
6769 max_bucket_size is the maximum size of a bucket, enforced after any
6770 speed_limit additions.
6772 Please see the delay_parameters option for more information and
6776 client_delay_parameters 1 1024 2048
6777 client_delay_parameters 2 51200 16384
6779 See also client_delay_access.
6783 NAME: client_delay_access
6784 TYPE: client_delay_pool_access
6786 DEFAULT_DOC: Deny use of the pool, unless allow rules exist in squid.conf for the pool.
6787 IFDEF: USE_DELAY_POOLS
6788 LOC: Config.ClientDelay
6790 This option determines the client-side delay pool for the
6793 client_delay_access pool_ID allow|deny acl_name
6795 All client_delay_access options are checked in their pool ID
6796 order, starting with pool 1. The first checked pool with allowed
6797 request is selected for the request. If no ACL matches or there
6798 are no client_delay_access options, the request bandwidth is not
6801 The ACL-selected pool is then used to find the
6802 client_delay_parameters for the request. Client-side pools are
6803 not used to aggregate clients. Clients are always aggregated
6804 based on their source IP addresses (one bucket per source IP).
6806 This clause only supports fast acl types.
6807 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6808 Additionally, only the client TCP connection details are available.
6809 ACLs testing HTTP properties will not work.
6811 Please see delay_access for more examples.
6814 client_delay_access 1 allow low_rate_network
6815 client_delay_access 2 allow vips_network
6818 See also client_delay_parameters and client_delay_pools.
6822 WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS
6823 -----------------------------------------------------------------------------
6828 LOC: Config.Wccp.router
6830 DEFAULT_DOC: WCCP disabled.
6833 Use this option to define your WCCP ``home'' router for
6836 wccp_router supports a single WCCP(v1) router
6838 wccp2_router supports multiple WCCPv2 routers
6840 only one of the two may be used at the same time and defines
6841 which version of WCCP to use.
6845 TYPE: IpAddress_list
6846 LOC: Config.Wccp2.router
6848 DEFAULT_DOC: WCCPv2 disabled.
6851 Use this option to define your WCCP ``home'' router for
6854 wccp_router supports a single WCCP(v1) router
6856 wccp2_router supports multiple WCCPv2 routers
6858 only one of the two may be used at the same time and defines
6859 which version of WCCP to use.
6864 LOC: Config.Wccp.version
6868 This directive is only relevant if you need to set up WCCP(v1)
6869 to some very old and end-of-life Cisco routers. In all other
6870 setups it must be left unset or at the default setting.
6871 It defines an internal version in the WCCP(v1) protocol,
6872 with version 4 being the officially documented protocol.
6874 According to some users, Cisco IOS 11.2 and earlier only
6875 support WCCP version 3. If you're using that or an earlier
6876 version of IOS, you may need to change this value to 3, otherwise
6877 do not specify this parameter.
6880 NAME: wccp2_rebuild_wait
6882 LOC: Config.Wccp2.rebuildwait
6886 If this is enabled Squid will wait for the cache dir rebuild to finish
6887 before sending the first wccp2 HereIAm packet
6890 NAME: wccp2_forwarding_method
6892 LOC: Config.Wccp2.forwarding_method
6896 WCCP2 allows the setting of forwarding methods between the
6897 router/switch and the cache. Valid values are as follows:
6899 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
6900 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
6902 Currently (as of IOS 12.4) cisco routers only support GRE.
6903 Cisco switches only support the L2 redirect assignment method.
6906 NAME: wccp2_return_method
6908 LOC: Config.Wccp2.return_method
6912 WCCP2 allows the setting of return methods between the
6913 router/switch and the cache for packets that the cache
6914 decides not to handle. Valid values are as follows:
6916 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
6917 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
6919 Currently (as of IOS 12.4) cisco routers only support GRE.
6920 Cisco switches only support the L2 redirect assignment.
6922 If the "ip wccp redirect exclude in" command has been
6923 enabled on the cache interface, then it is still safe for
6924 the proxy server to use a l2 redirect method even if this
6925 option is set to GRE.
6928 NAME: wccp2_assignment_method
6930 LOC: Config.Wccp2.assignment_method
6934 WCCP2 allows the setting of methods to assign the WCCP hash
6935 Valid values are as follows:
6937 hash - Hash assignment
6938 mask - Mask assignment
6940 As a general rule, cisco routers support the hash assignment method
6941 and cisco switches support the mask assignment method.
6946 LOC: Config.Wccp2.info
6947 DEFAULT_IF_NONE: standard 0
6948 DEFAULT_DOC: Use the 'web-cache' standard service.
6951 WCCP2 allows for multiple traffic services. There are two
6952 types: "standard" and "dynamic". The standard type defines
6953 one service id - http (id 0). The dynamic service ids can be from
6954 51 to 255 inclusive. In order to use a dynamic service id
6955 one must define the type of traffic to be redirected; this is done
6956 using the wccp2_service_info option.
6958 The "standard" type does not require a wccp2_service_info option,
6959 just specifying the service id will suffice.
6961 MD5 service authentication can be enabled by adding
6962 "password=<password>" to the end of this service declaration.
6966 wccp2_service standard 0 # for the 'web-cache' standard service
6967 wccp2_service dynamic 80 # a dynamic service type which will be
6968 # fleshed out with subsequent options.
6969 wccp2_service standard 0 password=foo
6972 NAME: wccp2_service_info
6973 TYPE: wccp2_service_info
6974 LOC: Config.Wccp2.info
6978 Dynamic WCCPv2 services require further information to define the
6979 traffic you wish to have diverted.
6983 wccp2_service_info <id> protocol=<protocol> flags=<flag>,<flag>..
6984 priority=<priority> ports=<port>,<port>..
6986 The relevant WCCPv2 flags:
6987 + src_ip_hash, dst_ip_hash
6988 + source_port_hash, dst_port_hash
6989 + src_ip_alt_hash, dst_ip_alt_hash
6990 + src_port_alt_hash, dst_port_alt_hash
6993 The port list can be one to eight entries.
6997 wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source
6998 priority=240 ports=80
7000 Note: the service id must have been defined by a previous
7001 'wccp2_service dynamic <id>' entry.
7006 LOC: Config.Wccp2.weight
7010 Each cache server gets assigned a set of the destination
7011 hash proportional to their weight.
7016 LOC: Config.Wccp.address
7018 DEFAULT_DOC: Address selected by the operating system.
7021 Use this option if you require WCCPv2 to use a specific
7024 The default behavior is to not bind to any specific address.
7029 LOC: Config.Wccp2.address
7031 DEFAULT_DOC: Address selected by the operating system.
7034 Use this option if you require WCCP to use a specific
7037 The default behavior is to not bind to any specific address.
7041 PERSISTENT CONNECTION HANDLING
7042 -----------------------------------------------------------------------------
7044 Also see "pconn_timeout" in the TIMEOUTS section
7047 NAME: client_persistent_connections
7049 LOC: Config.onoff.client_pconns
7052 Persistent connection support for clients.
7053 Squid uses persistent connections (when allowed). You can use
7054 this option to disable persistent connections with clients.
7057 NAME: server_persistent_connections
7059 LOC: Config.onoff.server_pconns
7062 Persistent connection support for servers.
7063 Squid uses persistent connections (when allowed). You can use
7064 this option to disable persistent connections with servers.
7067 NAME: persistent_connection_after_error
7069 LOC: Config.onoff.error_pconns
7072 With this directive the use of persistent connections after
7073 HTTP errors can be disabled. Useful if you have clients
7074 who fail to handle errors on persistent connections proper.
7077 NAME: detect_broken_pconn
7079 LOC: Config.onoff.detect_broken_server_pconns
7082 Some servers have been found to incorrectly signal the use
7083 of HTTP/1.0 persistent connections even on replies not
7084 compatible, causing significant delays. This server problem
7085 has mostly been seen on redirects.
7087 By enabling this directive Squid attempts to detect such
7088 broken replies and automatically assume the reply is finished
7089 after 10 seconds timeout.
7093 CACHE DIGEST OPTIONS
7094 -----------------------------------------------------------------------------
7097 NAME: digest_generation
7098 IFDEF: USE_CACHE_DIGESTS
7100 LOC: Config.onoff.digest_generation
7103 This controls whether the server will generate a Cache Digest
7104 of its contents. By default, Cache Digest generation is
7105 enabled if Squid is compiled with --enable-cache-digests defined.
7108 NAME: digest_bits_per_entry
7109 IFDEF: USE_CACHE_DIGESTS
7111 LOC: Config.digest.bits_per_entry
7114 This is the number of bits of the server's Cache Digest which
7115 will be associated with the Digest entry for a given HTTP
7116 Method and URL (public key) combination. The default is 5.
7119 NAME: digest_rebuild_period
7120 IFDEF: USE_CACHE_DIGESTS
7123 LOC: Config.digest.rebuild_period
7126 This is the wait time between Cache Digest rebuilds.
7129 NAME: digest_rewrite_period
7131 IFDEF: USE_CACHE_DIGESTS
7133 LOC: Config.digest.rewrite_period
7136 This is the wait time between Cache Digest writes to
7140 NAME: digest_swapout_chunk_size
7143 IFDEF: USE_CACHE_DIGESTS
7144 LOC: Config.digest.swapout_chunk_size
7147 This is the number of bytes of the Cache Digest to write to
7148 disk at a time. It defaults to 4096 bytes (4KB), the Squid
7152 NAME: digest_rebuild_chunk_percentage
7153 COMMENT: (percent, 0-100)
7154 IFDEF: USE_CACHE_DIGESTS
7156 LOC: Config.digest.rebuild_chunk_percentage
7159 This is the percentage of the Cache Digest to be scanned at a
7160 time. By default it is set to 10% of the Cache Digest.
7165 -----------------------------------------------------------------------------
7170 LOC: Config.Port.snmp
7172 DEFAULT_DOC: SNMP disabled.
7175 The port number where Squid listens for SNMP requests. To enable
7176 SNMP support set this to a suitable port number. Port number
7177 3401 is often used for the Squid SNMP agent. By default it's
7178 set to "0" (disabled)
7186 LOC: Config.accessList.snmp
7188 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
7191 Allowing or denying access to the SNMP port.
7193 All access to the agent is denied by default.
7196 snmp_access allow|deny [!]aclname ...
7198 This clause only supports fast acl types.
7199 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7202 snmp_access allow snmppublic localhost
7203 snmp_access deny all
7206 NAME: snmp_incoming_address
7208 LOC: Config.Addrs.snmp_incoming
7210 DEFAULT_DOC: Accept SNMP packets from all machine interfaces.
7213 Just like 'udp_incoming_address', but for the SNMP port.
7215 snmp_incoming_address is used for the SNMP socket receiving
7216 messages from SNMP agents.
7218 The default snmp_incoming_address is to listen on all
7219 available network interfaces.
7222 NAME: snmp_outgoing_address
7224 LOC: Config.Addrs.snmp_outgoing
7226 DEFAULT_DOC: Use snmp_incoming_address or an address selected by the operating system.
7229 Just like 'udp_outgoing_address', but for the SNMP port.
7231 snmp_outgoing_address is used for SNMP packets returned to SNMP
7234 If snmp_outgoing_address is not set it will use the same socket
7235 as snmp_incoming_address. Only change this if you want to have
7236 SNMP replies sent using another address than where this Squid
7237 listens for SNMP queries.
7239 NOTE, snmp_incoming_address and snmp_outgoing_address can not have
7240 the same value since they both use the same port.
7245 -----------------------------------------------------------------------------
7248 NAME: icp_port udp_port
7251 DEFAULT_DOC: ICP disabled.
7252 LOC: Config.Port.icp
7254 The port number where Squid sends and receives ICP queries to
7255 and from neighbor caches. The standard UDP port for ICP is 3130.
7258 icp_port @DEFAULT_ICP_PORT@
7265 DEFAULT_DOC: HTCP disabled.
7266 LOC: Config.Port.htcp
7268 The port number where Squid sends and receives HTCP queries to
7269 and from neighbor caches. To turn it on you want to set it to
7276 NAME: log_icp_queries
7280 LOC: Config.onoff.log_udp
7282 If set, ICP queries are logged to access.log. You may wish
7283 do disable this if your ICP load is VERY high to speed things
7284 up or to simplify log analysis.
7287 NAME: udp_incoming_address
7289 LOC:Config.Addrs.udp_incoming
7291 DEFAULT_DOC: Accept packets from all machine interfaces.
7293 udp_incoming_address is used for UDP packets received from other
7296 The default behavior is to not bind to any specific address.
7298 Only change this if you want to have all UDP queries received on
7299 a specific interface/address.
7301 NOTE: udp_incoming_address is used by the ICP, HTCP, and DNS
7302 modules. Altering it will affect all of them in the same manner.
7304 see also; udp_outgoing_address
7306 NOTE, udp_incoming_address and udp_outgoing_address can not
7307 have the same value since they both use the same port.
7310 NAME: udp_outgoing_address
7312 LOC: Config.Addrs.udp_outgoing
7314 DEFAULT_DOC: Use udp_incoming_address or an address selected by the operating system.
7316 udp_outgoing_address is used for UDP packets sent out to other
7319 The default behavior is to not bind to any specific address.
7321 Instead it will use the same socket as udp_incoming_address.
7322 Only change this if you want to have UDP queries sent using another
7323 address than where this Squid listens for UDP queries from other
7326 NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS
7327 modules. Altering it will affect all of them in the same manner.
7329 see also; udp_incoming_address
7331 NOTE, udp_incoming_address and udp_outgoing_address can not
7332 have the same value since they both use the same port.
7339 LOC: Config.onoff.icp_hit_stale
7341 If you want to return ICP_HIT for stale cache objects, set this
7342 option to 'on'. If you have sibling relationships with caches
7343 in other administrative domains, this should be 'off'. If you only
7344 have sibling relationships with caches under your control,
7345 it is probably okay to set this to 'on'.
7346 If set to 'on', your siblings should use the option "allow-miss"
7347 on their cache_peer lines for connecting to you.
7350 NAME: minimum_direct_hops
7353 LOC: Config.minDirectHops
7355 If using the ICMP pinging stuff, do direct fetches for sites
7356 which are no more than this many hops away.
7359 NAME: minimum_direct_rtt
7363 LOC: Config.minDirectRtt
7365 If using the ICMP pinging stuff, do direct fetches for sites
7366 which are no more than this many rtt milliseconds away.
7372 LOC: Config.Netdb.low
7374 The low water mark for the ICMP measurement database.
7376 Note: high watermark controlled by netdb_high directive.
7378 These watermarks are counts, not percents. The defaults are
7379 (low) 900 and (high) 1000. When the high water mark is
7380 reached, database entries will be deleted until the low
7387 LOC: Config.Netdb.high
7389 The high water mark for the ICMP measurement database.
7391 Note: low watermark controlled by netdb_low directive.
7393 These watermarks are counts, not percents. The defaults are
7394 (low) 900 and (high) 1000. When the high water mark is
7395 reached, database entries will be deleted until the low
7399 NAME: netdb_ping_period
7401 LOC: Config.Netdb.period
7404 The minimum period for measuring a site. There will be at
7405 least this much delay between successive pings to the same
7406 network. The default is five minutes.
7413 LOC: Config.onoff.query_icmp
7415 If you want to ask your peers to include ICMP data in their ICP
7416 replies, enable this option.
7418 If your peer has configured Squid (during compilation) with
7419 '--enable-icmp' that peer will send ICMP pings to origin server
7420 sites of the URLs it receives. If you enable this option the
7421 ICP replies from that peer will include the ICMP data (if available).
7422 Then, when choosing a parent cache, Squid will choose the parent with
7423 the minimal RTT to the origin server. When this happens, the
7424 hierarchy field of the access.log will be
7425 "CLOSEST_PARENT_MISS". This option is off by default.
7428 NAME: test_reachability
7432 LOC: Config.onoff.test_reachability
7434 When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
7435 instead of ICP_MISS if the target host is NOT in the ICMP
7436 database, or has a zero RTT.
7439 NAME: icp_query_timeout
7442 DEFAULT_DOC: Dynamic detection.
7444 LOC: Config.Timeout.icp_query
7446 Normally Squid will automatically determine an optimal ICP
7447 query timeout value based on the round-trip-time of recent ICP
7448 queries. If you want to override the value determined by
7449 Squid, set this 'icp_query_timeout' to a non-zero value. This
7450 value is specified in MILLISECONDS, so, to use a 2-second
7451 timeout (the old default), you would write:
7453 icp_query_timeout 2000
7456 NAME: maximum_icp_query_timeout
7460 LOC: Config.Timeout.icp_query_max
7462 Normally the ICP query timeout is determined dynamically. But
7463 sometimes it can lead to very large values (say 5 seconds).
7464 Use this option to put an upper limit on the dynamic timeout
7465 value. Do NOT use this option to always use a fixed (instead
7466 of a dynamic) timeout value. To set a fixed timeout see the
7467 'icp_query_timeout' directive.
7470 NAME: minimum_icp_query_timeout
7474 LOC: Config.Timeout.icp_query_min
7476 Normally the ICP query timeout is determined dynamically. But
7477 sometimes it can lead to very small timeouts, even lower than
7478 the normal latency variance on your link due to traffic.
7479 Use this option to put an lower limit on the dynamic timeout
7480 value. Do NOT use this option to always use a fixed (instead
7481 of a dynamic) timeout value. To set a fixed timeout see the
7482 'icp_query_timeout' directive.
7485 NAME: background_ping_rate
7489 LOC: Config.backgroundPingRate
7491 Controls how often the ICP pings are sent to siblings that
7492 have background-ping set.
7496 MULTICAST ICP OPTIONS
7497 -----------------------------------------------------------------------------
7502 LOC: Config.mcast_group_list
7505 This tag specifies a list of multicast groups which your server
7506 should join to receive multicasted ICP queries.
7508 NOTE! Be very careful what you put here! Be sure you
7509 understand the difference between an ICP _query_ and an ICP
7510 _reply_. This option is to be set only if you want to RECEIVE
7511 multicast queries. Do NOT set this option to SEND multicast
7512 ICP (use cache_peer for that). ICP replies are always sent via
7513 unicast, so this option does not affect whether or not you will
7514 receive replies from multicast group members.
7516 You must be very careful to NOT use a multicast address which
7517 is already in use by another group of caches.
7519 If you are unsure about multicast, please read the Multicast
7520 chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
7522 Usage: mcast_groups 239.128.16.128 224.0.1.20
7524 By default, Squid doesn't listen on any multicast groups.
7527 NAME: mcast_miss_addr
7528 IFDEF: MULTICAST_MISS_STREAM
7530 LOC: Config.mcast_miss.addr
7532 DEFAULT_DOC: disabled.
7534 If you enable this option, every "cache miss" URL will
7535 be sent out on the specified multicast address.
7537 Do not enable this option unless you are are absolutely
7538 certain you understand what you are doing.
7541 NAME: mcast_miss_ttl
7542 IFDEF: MULTICAST_MISS_STREAM
7544 LOC: Config.mcast_miss.ttl
7547 This is the time-to-live value for packets multicasted
7548 when multicasting off cache miss URLs is enabled. By
7549 default this is set to 'site scope', i.e. 16.
7552 NAME: mcast_miss_port
7553 IFDEF: MULTICAST_MISS_STREAM
7555 LOC: Config.mcast_miss.port
7558 This is the port number to be used in conjunction with
7562 NAME: mcast_miss_encode_key
7563 IFDEF: MULTICAST_MISS_STREAM
7565 LOC: Config.mcast_miss.encode_key
7566 DEFAULT: XXXXXXXXXXXXXXXX
7568 The URLs that are sent in the multicast miss stream are
7569 encrypted. This is the encryption key.
7572 NAME: mcast_icp_query_timeout
7576 LOC: Config.Timeout.mcast_icp_query
7578 For multicast peers, Squid regularly sends out ICP "probes" to
7579 count how many other peers are listening on the given multicast
7580 address. This value specifies how long Squid should wait to
7581 count all the replies. The default is 2000 msec, or 2
7586 INTERNAL ICON OPTIONS
7587 -----------------------------------------------------------------------------
7590 NAME: icon_directory
7592 LOC: Config.icons.directory
7593 DEFAULT: @DEFAULT_ICON_DIR@
7595 Where the icons are stored. These are normally kept in
7599 NAME: global_internal_static
7601 LOC: Config.onoff.global_internal_static
7604 This directive controls is Squid should intercept all requests for
7605 /squid-internal-static/ no matter which host the URL is requesting
7606 (default on setting), or if nothing special should be done for
7607 such URLs (off setting). The purpose of this directive is to make
7608 icons etc work better in complex cache hierarchies where it may
7609 not always be possible for all corners in the cache mesh to reach
7610 the server generating a directory listing.
7613 NAME: short_icon_urls
7615 LOC: Config.icons.use_short_names
7618 If this is enabled Squid will use short URLs for icons.
7619 If disabled it will revert to the old behavior of including
7620 it's own name and port in the URL.
7622 If you run a complex cache hierarchy with a mix of Squid and
7623 other proxies you may need to disable this directive.
7628 -----------------------------------------------------------------------------
7631 NAME: error_directory
7633 LOC: Config.errorDirectory
7635 DEFAULT_DOC: Send error pages in the clients preferred language
7637 If you wish to create your own versions of the default
7638 error files to customize them to suit your company copy
7639 the error/template files to another directory and point
7642 WARNING: This option will disable multi-language support
7643 on error pages if used.
7645 The squid developers are interested in making squid available in
7646 a wide variety of languages. If you are making translations for a
7647 language that Squid does not currently provide please consider
7648 contributing your translation back to the project.
7649 http://wiki.squid-cache.org/Translations
7651 The squid developers working on translations are happy to supply drop-in
7652 translated error files in exchange for any new language contributions.
7655 NAME: error_default_language
7656 IFDEF: USE_ERR_LOCALES
7658 LOC: Config.errorDefaultLanguage
7660 DEFAULT_DOC: Generate English language pages.
7662 Set the default language which squid will send error pages in
7663 if no existing translation matches the clients language
7666 If unset (default) generic English will be used.
7668 The squid developers are interested in making squid available in
7669 a wide variety of languages. If you are interested in making
7670 translations for any language see the squid wiki for details.
7671 http://wiki.squid-cache.org/Translations
7674 NAME: error_log_languages
7675 IFDEF: USE_ERR_LOCALES
7677 LOC: Config.errorLogMissingLanguages
7680 Log to cache.log what languages users are attempting to
7681 auto-negotiate for translations.
7683 Successful negotiations are not logged. Only failures
7684 have meaning to indicate that Squid may need an upgrade
7685 of its error page translations.
7688 NAME: err_page_stylesheet
7690 LOC: Config.errorStylesheet
7691 DEFAULT: @DEFAULT_CONFIG_DIR@/errorpage.css
7693 CSS Stylesheet to pattern the display of Squid default error pages.
7695 For information on CSS see http://www.w3.org/Style/CSS/
7700 LOC: Config.errHtmlText
7703 HTML text to include in error messages. Make this a "mailto"
7704 URL to your admin address, or maybe just a link to your
7705 organizations Web page.
7707 To include this in your error messages, you must rewrite
7708 the error template files (found in the "errors" directory).
7709 Wherever you want the 'err_html_text' line to appear,
7710 insert a %L tag in the error template file.
7713 NAME: email_err_data
7716 LOC: Config.onoff.emailErrData
7719 If enabled, information about the occurred error will be
7720 included in the mailto links of the ERR pages (if %W is set)
7721 so that the email body contains the data.
7722 Syntax is <A HREF="mailto:%w%W">%w</A>
7727 LOC: Config.denyInfoList
7730 Usage: deny_info err_page_name acl
7731 or deny_info http://... acl
7732 or deny_info TCP_RESET acl
7734 This can be used to return a ERR_ page for requests which
7735 do not pass the 'http_access' rules. Squid remembers the last
7736 acl it evaluated in http_access, and if a 'deny_info' line exists
7737 for that ACL Squid returns a corresponding error page.
7739 The acl is typically the last acl on the http_access deny line which
7740 denied access. The exceptions to this rule are:
7741 - When Squid needs to request authentication credentials. It's then
7742 the first authentication related acl encountered
7743 - When none of the http_access lines matches. It's then the last
7744 acl processed on the last http_access line.
7745 - When the decision to deny access was made by an adaptation service,
7746 the acl name is the corresponding eCAP or ICAP service_name.
7748 NP: If providing your own custom error pages with error_directory
7749 you may also specify them by your custom file name:
7750 Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
7752 By defaut Squid will send "403 Forbidden". A different 4xx or 5xx
7753 may be specified by prefixing the file name with the code and a colon.
7754 e.g. 404:ERR_CUSTOM_ACCESS_DENIED
7756 Alternatively you can tell Squid to reset the TCP connection
7757 by specifying TCP_RESET.
7759 Or you can specify an error URL or URL pattern. The browsers will
7760 get redirected to the specified URL after formatting tags have
7761 been replaced. Redirect will be done with 302 or 307 according to
7762 HTTP/1.1 specs. A different 3xx code may be specified by prefixing
7763 the URL. e.g. 303:http://example.com/
7766 %a - username (if available. Password NOT included)
7769 %E - Error description
7771 %H - Request domain name
7772 %i - Client IP Address
7774 %o - Message result from external ACL helper
7775 %p - Request Port number
7776 %P - Request Protocol name
7777 %R - Request URL path
7778 %T - Timestamp in RFC 1123 format
7779 %U - Full canonical URL from client
7780 (HTTPS URLs terminate with *)
7781 %u - Full canonical URL from client
7782 %w - Admin email from squid.conf
7784 %% - Literal percent (%) code
7789 OPTIONS INFLUENCING REQUEST FORWARDING
7790 -----------------------------------------------------------------------------
7793 NAME: nonhierarchical_direct
7795 LOC: Config.onoff.nonhierarchical_direct
7798 By default, Squid will send any non-hierarchical requests
7799 (not cacheable request type) direct to origin servers.
7801 When this is set to "off", Squid will prefer to send these
7802 requests to parents.
7804 Note that in most configurations, by turning this off you will only
7805 add latency to these request without any improvement in global hit
7808 This option only sets a preference. If the parent is unavailable a
7809 direct connection to the origin server may still be attempted. To
7810 completely prevent direct connections use never_direct.
7815 LOC: Config.onoff.prefer_direct
7818 Normally Squid tries to use parents for most requests. If you for some
7819 reason like it to first try going direct and only use a parent if
7820 going direct fails set this to on.
7822 By combining nonhierarchical_direct off and prefer_direct on you
7823 can set up Squid to use a parent as a backup path if going direct
7826 Note: If you want Squid to use parents for all requests see
7827 the never_direct directive. prefer_direct only modifies how Squid
7828 acts on cacheable requests.
7831 NAME: cache_miss_revalidate
7835 LOC: Config.onoff.cache_miss_revalidate
7837 RFC 7232 defines a conditional request mechanism to prevent
7838 response objects being unnecessarily transferred over the network.
7839 If that mechanism is used by the client and a cache MISS occurs
7840 it can prevent new cache entries being created.
7842 This option determines whether Squid on cache MISS will pass the
7843 client revalidation request to the server or tries to fetch new
7844 content for caching. It can be useful while the cache is mostly
7845 empty to more quickly have the cache populated by generating
7846 non-conditional GETs.
7848 When set to 'on' (default), Squid will pass all client If-* headers
7849 to the server. This permits server responses without a cacheable
7850 payload to be delivered and on MISS no new cache entry is created.
7852 When set to 'off' and if the request is cacheable, Squid will
7853 remove the clients If-Modified-Since and If-None-Match headers from
7854 the request sent to the server. This requests a 200 status response
7855 from the server to create a new cache entry with.
7860 LOC: Config.accessList.AlwaysDirect
7862 DEFAULT_DOC: Prevent any cache_peer being used for this request.
7864 Usage: always_direct allow|deny [!]aclname ...
7866 Here you can use ACL elements to specify requests which should
7867 ALWAYS be forwarded by Squid to the origin servers without using
7868 any peers. For example, to always directly forward requests for
7869 local servers ignoring any parents or siblings you may have use
7872 acl local-servers dstdomain my.domain.net
7873 always_direct allow local-servers
7875 To always forward FTP requests directly, use
7878 always_direct allow FTP
7880 NOTE: There is a similar, but opposite option named
7881 'never_direct'. You need to be aware that "always_direct deny
7882 foo" is NOT the same thing as "never_direct allow foo". You
7883 may need to use a deny rule to exclude a more-specific case of
7884 some other rule. Example:
7886 acl local-external dstdomain external.foo.net
7887 acl local-servers dstdomain .foo.net
7888 always_direct deny local-external
7889 always_direct allow local-servers
7891 NOTE: If your goal is to make the client forward the request
7892 directly to the origin server bypassing Squid then this needs
7893 to be done in the client configuration. Squid configuration
7894 can only tell Squid how Squid should fetch the object.
7896 NOTE: This directive is not related to caching. The replies
7897 is cached as usual even if you use always_direct. To not cache
7898 the replies see the 'cache' directive.
7900 This clause supports both fast and slow acl types.
7901 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7906 LOC: Config.accessList.NeverDirect
7908 DEFAULT_DOC: Allow DNS results to be used for this request.
7910 Usage: never_direct allow|deny [!]aclname ...
7912 never_direct is the opposite of always_direct. Please read
7913 the description for always_direct if you have not already.
7915 With 'never_direct' you can use ACL elements to specify
7916 requests which should NEVER be forwarded directly to origin
7917 servers. For example, to force the use of a proxy for all
7918 requests, except those in your local domain use something like:
7920 acl local-servers dstdomain .foo.net
7921 never_direct deny local-servers
7922 never_direct allow all
7924 or if Squid is inside a firewall and there are local intranet
7925 servers inside the firewall use something like:
7927 acl local-intranet dstdomain .foo.net
7928 acl local-external dstdomain external.foo.net
7929 always_direct deny local-external
7930 always_direct allow local-intranet
7931 never_direct allow all
7933 This clause supports both fast and slow acl types.
7934 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7938 ADVANCED NETWORKING OPTIONS
7939 -----------------------------------------------------------------------------
7942 NAME: incoming_udp_average incoming_icp_average
7945 LOC: Config.comm_incoming.udp.average
7947 Heavy voodoo here. I can't even believe you are reading this.
7948 Are you crazy? Don't even think about adjusting these unless
7949 you understand the algorithms in comm_select.c first!
7952 NAME: incoming_tcp_average incoming_http_average
7955 LOC: Config.comm_incoming.tcp.average
7957 Heavy voodoo here. I can't even believe you are reading this.
7958 Are you crazy? Don't even think about adjusting these unless
7959 you understand the algorithms in comm_select.c first!
7962 NAME: incoming_dns_average
7965 LOC: Config.comm_incoming.dns.average
7967 Heavy voodoo here. I can't even believe you are reading this.
7968 Are you crazy? Don't even think about adjusting these unless
7969 you understand the algorithms in comm_select.c first!
7972 NAME: min_udp_poll_cnt min_icp_poll_cnt
7975 LOC: Config.comm_incoming.udp.min_poll
7977 Heavy voodoo here. I can't even believe you are reading this.
7978 Are you crazy? Don't even think about adjusting these unless
7979 you understand the algorithms in comm_select.c first!
7982 NAME: min_dns_poll_cnt
7985 LOC: Config.comm_incoming.dns.min_poll
7987 Heavy voodoo here. I can't even believe you are reading this.
7988 Are you crazy? Don't even think about adjusting these unless
7989 you understand the algorithms in comm_select.c first!
7992 NAME: min_tcp_poll_cnt min_http_poll_cnt
7995 LOC: Config.comm_incoming.tcp.min_poll
7997 Heavy voodoo here. I can't even believe you are reading this.
7998 Are you crazy? Don't even think about adjusting these unless
7999 you understand the algorithms in comm_select.c first!
8005 LOC: Config.accept_filter
8009 The name of an accept(2) filter to install on Squid's
8010 listen socket(s). This feature is perhaps specific to
8011 FreeBSD and requires support in the kernel.
8013 The 'httpready' filter delays delivering new connections
8014 to Squid until a full HTTP request has been received.
8015 See the accf_http(9) man page for details.
8017 The 'dataready' filter delays delivering new connections
8018 to Squid until there is some data to process.
8019 See the accf_dataready(9) man page for details.
8023 The 'data' filter delays delivering of new connections
8024 to Squid until there is some data to process by TCP_ACCEPT_DEFER.
8025 You may optionally specify a number of seconds to wait by
8026 'data=N' where N is the number of seconds. Defaults to 30
8027 if not specified. See the tcp(7) man page for details.
8030 accept_filter httpready
8035 NAME: client_ip_max_connections
8037 LOC: Config.client_ip_max_connections
8039 DEFAULT_DOC: No limit.
8041 Set an absolute limit on the number of connections a single
8042 client IP can use. Any more than this and Squid will begin to drop
8043 new connections from the client until it closes some links.
8045 Note that this is a global limit. It affects all HTTP, HTCP, Gopher and FTP
8046 connections from the client. For finer control use the ACL access controls.
8048 Requires client_db to be enabled (the default).
8050 WARNING: This may noticably slow down traffic received via external proxies
8051 or NAT devices and cause them to rebound error messages back to their clients.
8054 NAME: tcp_recv_bufsize
8058 DEFAULT_DOC: Use operating system TCP defaults.
8059 LOC: Config.tcpRcvBufsz
8061 Size of receive buffer to set for TCP sockets. Probably just
8062 as easy to change your kernel's default.
8063 Omit from squid.conf to use the default buffer size.
8068 -----------------------------------------------------------------------------
8075 LOC: Adaptation::Icap::TheConfig.onoff
8078 If you want to enable the ICAP module support, set this to on.
8081 NAME: icap_connect_timeout
8084 LOC: Adaptation::Icap::TheConfig.connect_timeout_raw
8087 This parameter specifies how long to wait for the TCP connect to
8088 the requested ICAP server to complete before giving up and either
8089 terminating the HTTP transaction or bypassing the failure.
8091 The default for optional services is peer_connect_timeout.
8092 The default for essential services is connect_timeout.
8093 If this option is explicitly set, its value applies to all services.
8096 NAME: icap_io_timeout
8100 DEFAULT_DOC: Use read_timeout.
8101 LOC: Adaptation::Icap::TheConfig.io_timeout_raw
8104 This parameter specifies how long to wait for an I/O activity on
8105 an established, active ICAP connection before giving up and
8106 either terminating the HTTP transaction or bypassing the
8110 NAME: icap_service_failure_limit
8111 COMMENT: limit [in memory-depth time-units]
8112 TYPE: icap_service_failure_limit
8114 LOC: Adaptation::Icap::TheConfig
8117 The limit specifies the number of failures that Squid tolerates
8118 when establishing a new TCP connection with an ICAP service. If
8119 the number of failures exceeds the limit, the ICAP service is
8120 not used for new ICAP requests until it is time to refresh its
8123 A negative value disables the limit. Without the limit, an ICAP
8124 service will not be considered down due to connectivity failures
8125 between ICAP OPTIONS requests.
8127 Squid forgets ICAP service failures older than the specified
8128 value of memory-depth. The memory fading algorithm
8129 is approximate because Squid does not remember individual
8130 errors but groups them instead, splitting the option
8131 value into ten time slots of equal length.
8133 When memory-depth is 0 and by default this option has no
8134 effect on service failure expiration.
8136 Squid always forgets failures when updating service settings
8137 using an ICAP OPTIONS transaction, regardless of this option
8141 # suspend service usage after 10 failures in 5 seconds:
8142 icap_service_failure_limit 10 in 5 seconds
8145 NAME: icap_service_revival_delay
8148 LOC: Adaptation::Icap::TheConfig.service_revival_delay
8151 The delay specifies the number of seconds to wait after an ICAP
8152 OPTIONS request failure before requesting the options again. The
8153 failed ICAP service is considered "down" until fresh OPTIONS are
8156 The actual delay cannot be smaller than the hardcoded minimum
8157 delay of 30 seconds.
8160 NAME: icap_preview_enable
8164 LOC: Adaptation::Icap::TheConfig.preview_enable
8167 The ICAP Preview feature allows the ICAP server to handle the
8168 HTTP message by looking only at the beginning of the message body
8169 or even without receiving the body at all. In some environments,
8170 previews greatly speedup ICAP processing.
8172 During an ICAP OPTIONS transaction, the server may tell Squid what
8173 HTTP messages should be previewed and how big the preview should be.
8174 Squid will not use Preview if the server did not request one.
8176 To disable ICAP Preview for all ICAP services, regardless of
8177 individual ICAP server OPTIONS responses, set this option to "off".
8179 icap_preview_enable off
8182 NAME: icap_preview_size
8185 LOC: Adaptation::Icap::TheConfig.preview_size
8187 DEFAULT_DOC: No preview sent.
8189 The default size of preview data to be sent to the ICAP server.
8190 This value might be overwritten on a per server basis by OPTIONS requests.
8193 NAME: icap_206_enable
8197 LOC: Adaptation::Icap::TheConfig.allow206_enable
8200 206 (Partial Content) responses is an ICAP extension that allows the
8201 ICAP agents to optionally combine adapted and original HTTP message
8202 content. The decision to combine is postponed until the end of the
8203 ICAP response. Squid supports Partial Content extension by default.
8205 Activation of the Partial Content extension is negotiated with each
8206 ICAP service during OPTIONS exchange. Most ICAP servers should handle
8207 negotation correctly even if they do not support the extension, but
8208 some might fail. To disable Partial Content support for all ICAP
8209 services and to avoid any negotiation, set this option to "off".
8215 NAME: icap_default_options_ttl
8218 LOC: Adaptation::Icap::TheConfig.default_options_ttl
8221 The default TTL value for ICAP OPTIONS responses that don't have
8222 an Options-TTL header.
8225 NAME: icap_persistent_connections
8229 LOC: Adaptation::Icap::TheConfig.reuse_connections
8232 Whether or not Squid should use persistent connections to
8236 NAME: adaptation_send_client_ip icap_send_client_ip
8238 IFDEF: USE_ADAPTATION
8240 LOC: Adaptation::Config::send_client_ip
8243 If enabled, Squid shares HTTP client IP information with adaptation
8244 services. For ICAP, Squid adds the X-Client-IP header to ICAP requests.
8245 For eCAP, Squid sets the libecap::metaClientIp transaction option.
8247 See also: adaptation_uses_indirect_client
8250 NAME: adaptation_send_username icap_send_client_username
8252 IFDEF: USE_ADAPTATION
8254 LOC: Adaptation::Config::send_username
8257 This sends authenticated HTTP client username (if available) to
8258 the adaptation service.
8260 For ICAP, the username value is encoded based on the
8261 icap_client_username_encode option and is sent using the header
8262 specified by the icap_client_username_header option.
8265 NAME: icap_client_username_header
8268 LOC: Adaptation::Icap::TheConfig.client_username_header
8269 DEFAULT: X-Client-Username
8271 ICAP request header name to use for adaptation_send_username.
8274 NAME: icap_client_username_encode
8278 LOC: Adaptation::Icap::TheConfig.client_username_encode
8281 Whether to base64 encode the authenticated client username.
8285 TYPE: icap_service_type
8287 LOC: Adaptation::Icap::TheConfig
8290 Defines a single ICAP service using the following format:
8292 icap_service id vectoring_point uri [option ...]
8295 an opaque identifier or name which is used to direct traffic to
8296 this specific service. Must be unique among all adaptation
8297 services in squid.conf.
8299 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
8300 This specifies at which point of transaction processing the
8301 ICAP service should be activated. *_postcache vectoring points
8302 are not yet supported.
8304 uri: icap://servername:port/servicepath
8305 ICAP server and service location.
8306 icaps://servername:port/servicepath
8307 The "icap:" URI scheme is used for traditional ICAP server and
8308 service location (default port is 1344, connections are not
8309 encrypted). The "icaps:" URI scheme is for Secure ICAP
8310 services that use SSL/TLS-encrypted ICAP connections (by
8311 default, on port 11344).
8313 ICAP does not allow a single service to handle both REQMOD and RESPMOD
8314 transactions. Squid does not enforce that requirement. You can specify
8315 services with the same service_url and different vectoring_points. You
8316 can even specify multiple identical services as long as their
8317 service_names differ.
8319 To activate a service, use the adaptation_access directive. To group
8320 services, use adaptation_service_chain and adaptation_service_set.
8322 Service options are separated by white space. ICAP services support
8323 the following name=value options:
8326 If set to 'on' or '1', the ICAP service is treated as
8327 optional. If the service cannot be reached or malfunctions,
8328 Squid will try to ignore any errors and process the message as
8329 if the service was not enabled. No all ICAP errors can be
8330 bypassed. If set to 0, the ICAP service is treated as
8331 essential and all ICAP errors will result in an error page
8332 returned to the HTTP client.
8334 Bypass is off by default: services are treated as essential.
8337 If set to 'on' or '1', the ICAP service is allowed to
8338 dynamically change the current message adaptation plan by
8339 returning a chain of services to be used next. The services
8340 are specified using the X-Next-Services ICAP response header
8341 value, formatted as a comma-separated list of service names.
8342 Each named service should be configured in squid.conf. Other
8343 services are ignored. An empty X-Next-Services value results
8344 in an empty plan which ends the current adaptation.
8346 Dynamic adaptation plan may cross or cover multiple supported
8347 vectoring points in their natural processing order.
8349 Routing is not allowed by default: the ICAP X-Next-Services
8350 response header is ignored.
8353 Only has effect on split-stack systems. The default on those systems
8354 is to use IPv4-only connections. When set to 'on' this option will
8355 make Squid use IPv6-only connections to contact this ICAP service.
8357 on-overload=block|bypass|wait|force
8358 If the service Max-Connections limit has been reached, do
8359 one of the following for each new ICAP transaction:
8360 * block: send an HTTP error response to the client
8361 * bypass: ignore the "over-connected" ICAP service
8362 * wait: wait (in a FIFO queue) for an ICAP connection slot
8363 * force: proceed, ignoring the Max-Connections limit
8365 In SMP mode with N workers, each worker assumes the service
8366 connection limit is Max-Connections/N, even though not all
8367 workers may use a given service.
8369 The default value is "bypass" if service is bypassable,
8370 otherwise it is set to "wait".
8374 Use the given number as the Max-Connections limit, regardless
8375 of the Max-Connections value given by the service, if any.
8377 ==== ICAPS / TLS OPTIONS ====
8379 These options are used for Secure ICAP (icaps://....) services only.
8381 tls-cert=/path/to/ssl/certificate
8382 A client SSL certificate to use when connecting to
8385 tls-key=/path/to/ssl/key
8386 The private TLS/SSL key corresponding to sslcert above.
8387 If 'tls-key' is not specified 'tls-cert' is assumed to
8388 reference a combined PEM format file containing both the
8389 certificate and the key.
8391 tls-cipher=... The list of valid TLS/SSL ciphers to use when connecting
8392 to this icap server.
8395 The minimum TLS protocol version to permit. To control
8396 SSLv3 use the ssloptions= parameter.
8397 Supported Values: 1.0 (default), 1.1, 1.2
8399 tls-options=... Specify various OpenSSL library options:
8401 NO_SSLv3 Disallow the use of SSLv3
8403 NO_TLSv1 Disallow the use of TLSv1.0
8404 NO_TLSv1_1 Disallow the use of TLSv1.1
8405 NO_TLSv1_2 Disallow the use of TLSv1.2
8408 Always create a new key when using
8409 temporary/ephemeral DH key exchanges
8411 ALL Enable various bug workarounds
8412 suggested as "harmless" by OpenSSL
8413 Be warned that this reduces SSL/TLS
8414 strength to some attacks.
8416 See the OpenSSL SSL_CTX_set_options documentation for a
8417 more complete list. Options relevant only to SSLv2 are
8420 tls-cafile= PEM file containing CA certificates to use when verifying
8421 the icap server certificate.
8422 Use to specify intermediate CA certificate(s) if not sent
8423 by the server. Or the full CA chain for the server when
8424 using the tls-no-default-ca flag.
8425 May be repeated to load multiple files.
8427 tls-capath=... A directory containing additional CA certificates to
8428 use when verifying the icap server certificate.
8429 Requires OpenSSL or LibreSSL.
8431 tls-crlfile=... A certificate revocation list file to use when
8432 verifying the icap server certificate.
8434 tls-flags=... Specify various flags modifying the Squid TLS implementation:
8437 Accept certificates even if they fail to
8440 Don't verify the icap server certificate
8441 matches the server name
8444 Do no use the system default Trusted CA.
8446 tls-domain= The icap server name as advertised in it's certificate.
8447 Used for verifying the correctness of the received icap
8448 server certificate. If not specified the icap server
8449 hostname extracted from ICAP URI will be used.
8451 Older icap_service format without optional named parameters is
8452 deprecated but supported for backward compatibility.
8455 icap_service svcBlocker reqmod_precache icap://icap1.mydomain.net:1344/reqmod bypass=0
8456 icap_service svcLogger reqmod_precache icaps://icap2.mydomain.net:11344/reqmod routing=on
8460 TYPE: icap_class_type
8465 This deprecated option was documented to define an ICAP service
8466 chain, even though it actually defined a set of similar, redundant
8467 services, and the chains were not supported.
8469 To define a set of redundant services, please use the
8470 adaptation_service_set directive. For service chains, use
8471 adaptation_service_chain.
8475 TYPE: icap_access_type
8480 This option is deprecated. Please use adaptation_access, which
8481 has the same ICAP functionality, but comes with better
8482 documentation, and eCAP support.
8487 -----------------------------------------------------------------------------
8494 LOC: Adaptation::Ecap::TheConfig.onoff
8497 Controls whether eCAP support is enabled.
8501 TYPE: ecap_service_type
8503 LOC: Adaptation::Ecap::TheConfig
8506 Defines a single eCAP service
8508 ecap_service id vectoring_point uri [option ...]
8511 an opaque identifier or name which is used to direct traffic to
8512 this specific service. Must be unique among all adaptation
8513 services in squid.conf.
8515 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
8516 This specifies at which point of transaction processing the
8517 eCAP service should be activated. *_postcache vectoring points
8518 are not yet supported.
8520 uri: ecap://vendor/service_name?custom&cgi=style¶meters=optional
8521 Squid uses the eCAP service URI to match this configuration
8522 line with one of the dynamically loaded services. Each loaded
8523 eCAP service must have a unique URI. Obtain the right URI from
8524 the service provider.
8526 To activate a service, use the adaptation_access directive. To group
8527 services, use adaptation_service_chain and adaptation_service_set.
8529 Service options are separated by white space. eCAP services support
8530 the following name=value options:
8533 If set to 'on' or '1', the eCAP service is treated as optional.
8534 If the service cannot be reached or malfunctions, Squid will try
8535 to ignore any errors and process the message as if the service
8536 was not enabled. No all eCAP errors can be bypassed.
8537 If set to 'off' or '0', the eCAP service is treated as essential
8538 and all eCAP errors will result in an error page returned to the
8541 Bypass is off by default: services are treated as essential.
8544 If set to 'on' or '1', the eCAP service is allowed to
8545 dynamically change the current message adaptation plan by
8546 returning a chain of services to be used next.
8548 Dynamic adaptation plan may cross or cover multiple supported
8549 vectoring points in their natural processing order.
8551 Routing is not allowed by default.
8553 Older ecap_service format without optional named parameters is
8554 deprecated but supported for backward compatibility.
8558 ecap_service s1 reqmod_precache ecap://filters.R.us/leakDetector?on_error=block bypass=off
8559 ecap_service s2 respmod_precache ecap://filters.R.us/virusFilter config=/etc/vf.cfg bypass=on
8562 NAME: loadable_modules
8564 IFDEF: USE_LOADABLE_MODULES
8565 LOC: Config.loadable_module_names
8568 Instructs Squid to load the specified dynamic module(s) or activate
8569 preloaded module(s).
8571 loadable_modules @DEFAULT_PREFIX@/lib/MinimalAdapter.so
8575 MESSAGE ADAPTATION OPTIONS
8576 -----------------------------------------------------------------------------
8579 NAME: adaptation_service_set
8580 TYPE: adaptation_service_set_type
8581 IFDEF: USE_ADAPTATION
8586 Configures an ordered set of similar, redundant services. This is
8587 useful when hot standby or backup adaptation servers are available.
8589 adaptation_service_set set_name service_name1 service_name2 ...
8591 The named services are used in the set declaration order. The first
8592 applicable adaptation service from the set is used first. The next
8593 applicable service is tried if and only if the transaction with the
8594 previous service fails and the message waiting to be adapted is still
8597 When adaptation starts, broken services are ignored as if they were
8598 not a part of the set. A broken service is a down optional service.
8600 The services in a set must be attached to the same vectoring point
8601 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
8603 If all services in a set are optional then adaptation failures are
8604 bypassable. If all services in the set are essential, then a
8605 transaction failure with one service may still be retried using
8606 another service from the set, but when all services fail, the master
8607 transaction fails as well.
8609 A set may contain a mix of optional and essential services, but that
8610 is likely to lead to surprising results because broken services become
8611 ignored (see above), making previously bypassable failures fatal.
8612 Technically, it is the bypassability of the last failed service that
8615 See also: adaptation_access adaptation_service_chain
8618 adaptation_service_set svcBlocker urlFilterPrimary urlFilterBackup
8619 adaptation service_set svcLogger loggerLocal loggerRemote
8622 NAME: adaptation_service_chain
8623 TYPE: adaptation_service_chain_type
8624 IFDEF: USE_ADAPTATION
8629 Configures a list of complementary services that will be applied
8630 one-by-one, forming an adaptation chain or pipeline. This is useful
8631 when Squid must perform different adaptations on the same message.
8633 adaptation_service_chain chain_name service_name1 svc_name2 ...
8635 The named services are used in the chain declaration order. The first
8636 applicable adaptation service from the chain is used first. The next
8637 applicable service is applied to the successful adaptation results of
8638 the previous service in the chain.
8640 When adaptation starts, broken services are ignored as if they were
8641 not a part of the chain. A broken service is a down optional service.
8643 Request satisfaction terminates the adaptation chain because Squid
8644 does not currently allow declaration of RESPMOD services at the
8645 "reqmod_precache" vectoring point (see icap_service or ecap_service).
8647 The services in a chain must be attached to the same vectoring point
8648 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
8650 A chain may contain a mix of optional and essential services. If an
8651 essential adaptation fails (or the failure cannot be bypassed for
8652 other reasons), the master transaction fails. Otherwise, the failure
8653 is bypassed as if the failed adaptation service was not in the chain.
8655 See also: adaptation_access adaptation_service_set
8658 adaptation_service_chain svcRequest requestLogger urlFilter leakDetector
8661 NAME: adaptation_access
8662 TYPE: adaptation_access_type
8663 IFDEF: USE_ADAPTATION
8666 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
8668 Sends an HTTP transaction to an ICAP or eCAP adaptation service.
8670 adaptation_access service_name allow|deny [!]aclname...
8671 adaptation_access set_name allow|deny [!]aclname...
8673 At each supported vectoring point, the adaptation_access
8674 statements are processed in the order they appear in this
8675 configuration file. Statements pointing to the following services
8676 are ignored (i.e., skipped without checking their ACL):
8678 - services serving different vectoring points
8679 - "broken-but-bypassable" services
8680 - "up" services configured to ignore such transactions
8681 (e.g., based on the ICAP Transfer-Ignore header).
8683 When a set_name is used, all services in the set are checked
8684 using the same rules, to find the first applicable one. See
8685 adaptation_service_set for details.
8687 If an access list is checked and there is a match, the
8688 processing stops: For an "allow" rule, the corresponding
8689 adaptation service is used for the transaction. For a "deny"
8690 rule, no adaptation service is activated.
8692 It is currently not possible to apply more than one adaptation
8693 service at the same vectoring point to the same HTTP transaction.
8695 See also: icap_service and ecap_service
8698 adaptation_access service_1 allow all
8701 NAME: adaptation_service_iteration_limit
8703 IFDEF: USE_ADAPTATION
8704 LOC: Adaptation::Config::service_iteration_limit
8707 Limits the number of iterations allowed when applying adaptation
8708 services to a message. If your longest adaptation set or chain
8709 may have more than 16 services, increase the limit beyond its
8710 default value of 16. If detecting infinite iteration loops sooner
8711 is critical, make the iteration limit match the actual number
8712 of services in your longest adaptation set or chain.
8714 Infinite adaptation loops are most likely with routing services.
8716 See also: icap_service routing=1
8719 NAME: adaptation_masterx_shared_names
8721 IFDEF: USE_ADAPTATION
8722 LOC: Adaptation::Config::masterx_shared_name
8725 For each master transaction (i.e., the HTTP request and response
8726 sequence, including all related ICAP and eCAP exchanges), Squid
8727 maintains a table of metadata. The table entries are (name, value)
8728 pairs shared among eCAP and ICAP exchanges. The table is destroyed
8729 with the master transaction.
8731 This option specifies the table entry names that Squid must accept
8732 from and forward to the adaptation transactions.
8734 An ICAP REQMOD or RESPMOD transaction may set an entry in the
8735 shared table by returning an ICAP header field with a name
8736 specified in adaptation_masterx_shared_names.
8738 An eCAP REQMOD or RESPMOD transaction may set an entry in the
8739 shared table by implementing the libecap::visitEachOption() API
8740 to provide an option with a name specified in
8741 adaptation_masterx_shared_names.
8743 Squid will store and forward the set entry to subsequent adaptation
8744 transactions within the same master transaction scope.
8746 Only one shared entry name is supported at this time.
8749 # share authentication information among ICAP services
8750 adaptation_masterx_shared_names X-Subscriber-ID
8753 NAME: adaptation_meta
8755 IFDEF: USE_ADAPTATION
8756 LOC: Adaptation::Config::metaHeaders
8759 This option allows Squid administrator to add custom ICAP request
8760 headers or eCAP options to Squid ICAP requests or eCAP transactions.
8761 Use it to pass custom authentication tokens and other
8762 transaction-state related meta information to an ICAP/eCAP service.
8764 The addition of a meta header is ACL-driven:
8765 adaptation_meta name value [!]aclname ...
8767 Processing for a given header name stops after the first ACL list match.
8768 Thus, it is impossible to add two headers with the same name. If no ACL
8769 lists match for a given header name, no such header is added. For
8772 # do not debug transactions except for those that need debugging
8773 adaptation_meta X-Debug 1 needs_debugging
8775 # log all transactions except for those that must remain secret
8776 adaptation_meta X-Log 1 !keep_secret
8778 # mark transactions from users in the "G 1" group
8779 adaptation_meta X-Authenticated-Groups "G 1" authed_as_G1
8781 The "value" parameter may be a regular squid.conf token or a "double
8782 quoted string". Within the quoted string, use backslash (\) to escape
8783 any character, which is currently only useful for escaping backslashes
8784 and double quotes. For example,
8785 "this string has one backslash (\\) and two \"quotes\""
8787 Used adaptation_meta header values may be logged via %note
8788 logformat code. If multiple adaptation_meta headers with the same name
8789 are used during master transaction lifetime, the header values are
8790 logged in the order they were used and duplicate values are ignored
8791 (only the first repeated value will be logged).
8797 LOC: Adaptation::Icap::TheConfig.repeat
8798 DEFAULT_IF_NONE: deny all
8800 This ACL determines which retriable ICAP transactions are
8801 retried. Transactions that received a complete ICAP response
8802 and did not have to consume or produce HTTP bodies to receive
8803 that response are usually retriable.
8805 icap_retry allow|deny [!]aclname ...
8807 Squid automatically retries some ICAP I/O timeouts and errors
8808 due to persistent connection race conditions.
8810 See also: icap_retry_limit
8813 NAME: icap_retry_limit
8816 LOC: Adaptation::Icap::TheConfig.repeat_limit
8818 DEFAULT_DOC: No retries are allowed.
8820 Limits the number of retries allowed.
8822 Communication errors due to persistent connection race
8823 conditions are unavoidable, automatically retried, and do not
8824 count against this limit.
8826 See also: icap_retry
8832 -----------------------------------------------------------------------------
8835 NAME: check_hostnames
8838 LOC: Config.onoff.check_hostnames
8840 For security and stability reasons Squid can check
8841 hostnames for Internet standard RFC compliance. If you want
8842 Squid to perform these checks turn this directive on.
8845 NAME: allow_underscore
8848 LOC: Config.onoff.allow_underscore
8850 Underscore characters is not strictly allowed in Internet hostnames
8851 but nevertheless used by many sites. Set this to off if you want
8852 Squid to be strict about the standard.
8853 This check is performed only when check_hostnames is set to on.
8856 NAME: dns_retransmit_interval
8859 LOC: Config.Timeout.idns_retransmit
8861 Initial retransmit interval for DNS queries. The interval is
8862 doubled each time all configured DNS servers have been tried.
8868 LOC: Config.Timeout.idns_query
8870 DNS Query timeout. If no response is received to a DNS query
8871 within this time all DNS servers for the queried domain
8872 are assumed to be unavailable.
8875 NAME: dns_packet_max
8877 DEFAULT_DOC: EDNS disabled
8879 LOC: Config.dns.packet_max
8881 Maximum number of bytes packet size to advertise via EDNS.
8882 Set to "none" to disable EDNS large packet support.
8884 For legacy reasons DNS UDP replies will default to 512 bytes which
8885 is too small for many responses. EDNS provides a means for Squid to
8886 negotiate receiving larger responses back immediately without having
8887 to failover with repeat requests. Responses larger than this limit
8888 will retain the old behaviour of failover to TCP DNS.
8890 Squid has no real fixed limit internally, but allowing packet sizes
8891 over 1500 bytes requires network jumbogram support and is usually not
8894 WARNING: The RFC also indicates that some older resolvers will reply
8895 with failure of the whole request if the extension is added. Some
8896 resolvers have already been identified which will reply with mangled
8897 EDNS response on occasion. Usually in response to many-KB jumbogram
8898 sizes being advertised by Squid.
8899 Squid will currently treat these both as an unable-to-resolve domain
8900 even if it would be resolvable without EDNS.
8907 DEFAULT_DOC: Search for single-label domain names is disabled.
8908 LOC: Config.onoff.res_defnames
8910 Normally the RES_DEFNAMES resolver option is disabled
8911 (see res_init(3)). This prevents caches in a hierarchy
8912 from interpreting single-component hostnames locally. To allow
8913 Squid to handle single-component names, enable this option.
8916 NAME: dns_multicast_local
8920 DEFAULT_DOC: Search for .local and .arpa names is disabled.
8921 LOC: Config.onoff.dns_mdns
8923 When set to on, Squid sends multicast DNS lookups on the local
8924 network for domains ending in .local and .arpa.
8925 This enables local servers and devices to be contacted in an
8926 ad-hoc or zero-configuration network environment.
8929 NAME: dns_nameservers
8932 DEFAULT_DOC: Use operating system definitions
8933 LOC: Config.dns_nameservers
8935 Use this if you want to specify a list of DNS name servers
8936 (IP addresses) to use instead of those given in your
8937 /etc/resolv.conf file.
8939 On Windows platforms, if no value is specified here or in
8940 the /etc/resolv.conf file, the list of DNS name servers are
8941 taken from the Windows registry, both static and dynamic DHCP
8942 configurations are supported.
8944 Example: dns_nameservers 10.0.0.1 192.172.0.4
8949 DEFAULT: @DEFAULT_HOSTS@
8950 LOC: Config.etcHostsPath
8952 Location of the host-local IP name-address associations
8953 database. Most Operating Systems have such a file on different
8955 - Un*X & Linux: /etc/hosts
8956 - Windows NT/2000: %SystemRoot%\system32\drivers\etc\hosts
8957 (%SystemRoot% value install default is c:\winnt)
8958 - Windows XP/2003: %SystemRoot%\system32\drivers\etc\hosts
8959 (%SystemRoot% value install default is c:\windows)
8960 - Windows 9x/Me: %windir%\hosts
8961 (%windir% value is usually c:\windows)
8962 - Cygwin: /etc/hosts
8964 The file contains newline-separated definitions, in the
8965 form ip_address_in_dotted_form name [name ...] names are
8966 whitespace-separated. Lines beginning with an hash (#)
8967 character are comments.
8969 The file is checked at startup and upon configuration.
8970 If set to 'none', it won't be checked.
8971 If append_domain is used, that domain will be added to
8972 domain-local (i.e. not containing any dot character) host
8978 LOC: Config.appendDomain
8980 DEFAULT_DOC: Use operating system definitions
8982 Appends local domain name to hostnames without any dots in
8983 them. append_domain must begin with a period.
8985 Be warned there are now Internet names with no dots in
8986 them using only top-domain names, so setting this may
8987 cause some Internet sites to become unavailable.
8990 append_domain .yourdomain.com
8993 NAME: ignore_unknown_nameservers
8995 LOC: Config.onoff.ignore_unknown_nameservers
8998 By default Squid checks that DNS responses are received
8999 from the same IP addresses they are sent to. If they
9000 don't match, Squid ignores the response and writes a warning
9001 message to cache.log. You can allow responses from unknown
9002 nameservers by setting this option to 'off'.
9008 LOC: Config.dns.v4_first
9010 With the IPv6 Internet being as fast or faster than IPv4 Internet
9011 for most networks Squid prefers to contact websites over IPv6.
9013 This option reverses the order of preference to make Squid contact
9014 dual-stack websites over IPv4 first. Squid will still perform both
9015 IPv6 and IPv4 DNS lookups before connecting.
9018 This option will restrict the situations under which IPv6
9019 connectivity is used (and tested). Hiding network problems
9020 which would otherwise be detected and warned about.
9024 COMMENT: (number of entries)
9027 LOC: Config.ipcache.size
9029 Maximum number of DNS IP cache entries.
9036 LOC: Config.ipcache.low
9043 LOC: Config.ipcache.high
9045 The size, low-, and high-water marks for the IP cache.
9048 NAME: fqdncache_size
9049 COMMENT: (number of entries)
9052 LOC: Config.fqdncache.size
9054 Maximum number of FQDN cache entries.
9059 -----------------------------------------------------------------------------
9062 NAME: configuration_includes_quoted_values
9064 TYPE: configuration_includes_quoted_values
9066 LOC: ConfigParser::RecognizeQuotedValues
9068 If set, Squid will recognize each "quoted string" after a configuration
9069 directive as a single parameter. The quotes are stripped before the
9070 parameter value is interpreted or used.
9071 See "Values with spaces, quotes, and other special characters"
9072 section for more details.
9079 LOC: Config.onoff.mem_pools
9081 If set, Squid will keep pools of allocated (but unused) memory
9082 available for future use. If memory is a premium on your
9083 system and you believe your malloc library outperforms Squid
9084 routines, disable this.
9087 NAME: memory_pools_limit
9091 LOC: Config.MemPools.limit
9093 Used only with memory_pools on:
9094 memory_pools_limit 50 MB
9096 If set to a non-zero value, Squid will keep at most the specified
9097 limit of allocated (but unused) memory in memory pools. All free()
9098 requests that exceed this limit will be handled by your malloc
9099 library. Squid does not pre-allocate any memory, just safe-keeps
9100 objects that otherwise would be free()d. Thus, it is safe to set
9101 memory_pools_limit to a reasonably high value even if your
9102 configuration will use less memory.
9104 If set to none, Squid will keep all memory it can. That is, there
9105 will be no limit on the total amount of memory used for safe-keeping.
9107 To disable memory allocation optimization, do not set
9108 memory_pools_limit to 0 or none. Set memory_pools to "off" instead.
9110 An overhead for maintaining memory pools is not taken into account
9111 when the limit is checked. This overhead is close to four bytes per
9112 object kept. However, pools may actually _save_ memory because of
9113 reduced memory thrashing in your malloc library.
9117 COMMENT: on|off|transparent|truncate|delete
9120 LOC: opt_forwarded_for
9122 If set to "on", Squid will append your client's IP address
9123 in the HTTP requests it forwards. By default it looks like:
9125 X-Forwarded-For: 192.1.2.3
9127 If set to "off", it will appear as
9129 X-Forwarded-For: unknown
9131 If set to "transparent", Squid will not alter the
9132 X-Forwarded-For header in any way.
9134 If set to "delete", Squid will delete the entire
9135 X-Forwarded-For header.
9137 If set to "truncate", Squid will remove all existing
9138 X-Forwarded-For entries, and place the client IP as the sole entry.
9141 NAME: cachemgr_passwd
9142 TYPE: cachemgrpasswd
9144 DEFAULT_DOC: No password. Actions which require password are denied.
9145 LOC: Config.passwd_list
9147 Specify passwords for cachemgr operations.
9149 Usage: cachemgr_passwd password action action ...
9151 Some valid actions are (see cache manager menu for a full list):
9191 * Indicates actions which will not be performed without a
9192 valid password, others can be performed if not listed here.
9194 To disable an action, set the password to "disable".
9195 To allow performing an action without a password, set the
9198 Use the keyword "all" to set the same password for all actions.
9201 cachemgr_passwd secret shutdown
9202 cachemgr_passwd lesssssssecret info stats/objects
9203 cachemgr_passwd disable all
9210 LOC: Config.onoff.client_db
9212 If you want to disable collecting per-client statistics,
9213 turn off client_db here.
9216 NAME: refresh_all_ims
9220 LOC: Config.onoff.refresh_all_ims
9222 When you enable this option, squid will always check
9223 the origin server for an update when a client sends an
9224 If-Modified-Since request. Many browsers use IMS
9225 requests when the user requests a reload, and this
9226 ensures those clients receive the latest version.
9228 By default (off), squid may return a Not Modified response
9229 based on the age of the cached version.
9232 NAME: reload_into_ims
9233 IFDEF: USE_HTTP_VIOLATIONS
9237 LOC: Config.onoff.reload_into_ims
9239 When you enable this option, client no-cache or ``reload''
9240 requests will be changed to If-Modified-Since requests.
9241 Doing this VIOLATES the HTTP standard. Enabling this
9242 feature could make you liable for problems which it
9245 see also refresh_pattern for a more selective approach.
9248 NAME: connect_retries
9250 LOC: Config.connect_retries
9252 DEFAULT_DOC: Do not retry failed connections.
9254 This sets the maximum number of connection attempts made for each
9255 TCP connection. The connect_retries attempts must all still
9256 complete within the connection timeout period.
9258 The default is not to re-try if the first connection attempt fails.
9259 The (not recommended) maximum is 10 tries.
9261 A warning message will be generated if it is set to a too-high
9262 value and the configured value will be over-ridden.
9264 Note: These re-tries are in addition to forward_max_tries
9265 which limit how many different addresses may be tried to find
9269 NAME: retry_on_error
9271 LOC: Config.retry.onerror
9274 If set to ON Squid will automatically retry requests when
9275 receiving an error response with status 403 (Forbidden),
9276 500 (Internal Error), 501 or 503 (Service not available).
9277 Status 502 and 504 (Gateway errors) are always retried.
9279 This is mainly useful if you are in a complex cache hierarchy to
9280 work around access control errors.
9282 NOTE: This retry will attempt to find another working destination.
9283 Which is different from the server which just failed.
9286 NAME: as_whois_server
9288 LOC: Config.as_whois_server
9289 DEFAULT: whois.ra.net
9291 WHOIS server to query for AS numbers. NOTE: AS numbers are
9292 queried only when Squid starts up, not for every request.
9297 LOC: Config.onoff.offline
9300 Enable this option and Squid will never try to validate cached
9304 NAME: uri_whitespace
9305 TYPE: uri_whitespace
9306 LOC: Config.uri_whitespace
9309 What to do with requests that have whitespace characters in the
9312 strip: The whitespace characters are stripped out of the URL.
9313 This is the behavior recommended by RFC2396 and RFC3986
9314 for tolerant handling of generic URI.
9315 NOTE: This is one difference between generic URI and HTTP URLs.
9317 deny: The request is denied. The user receives an "Invalid
9319 This is the behaviour recommended by RFC2616 for safe
9320 handling of HTTP request URL.
9322 allow: The request is allowed and the URI is not changed. The
9323 whitespace characters remain in the URI. Note the
9324 whitespace is passed to redirector processes if they
9326 Note this may be considered a violation of RFC2616
9327 request parsing where whitespace is prohibited in the
9330 encode: The request is allowed and the whitespace characters are
9331 encoded according to RFC1738.
9333 chop: The request is allowed and the URI is chopped at the
9337 NOTE the current Squid implementation of encode and chop violates
9338 RFC2616 by not using a 301 redirect after altering the URL.
9343 LOC: Config.chroot_dir
9346 Specifies a directory where Squid should do a chroot() while
9347 initializing. This also causes Squid to fully drop root
9348 privileges after initializing. This means, for example, if you
9349 use a HTTP port less than 1024 and try to reconfigure, you may
9350 get an error saying that Squid can not open the port.
9353 NAME: balance_on_multiple_ip
9355 LOC: Config.onoff.balance_on_multiple_ip
9358 Modern IP resolvers in squid sort lookup results by preferred access.
9359 By default squid will use these IP in order and only rotates to
9360 the next listed when the most preffered fails.
9362 Some load balancing servers based on round robin DNS have been
9363 found not to preserve user session state across requests
9364 to different IP addresses.
9366 Enabling this directive Squid rotates IP's per request.
9369 NAME: pipeline_prefetch
9370 TYPE: pipelinePrefetch
9371 LOC: Config.pipeline_max_prefetch
9373 DEFAULT_DOC: Do not pre-parse pipelined requests.
9375 HTTP clients may send a pipeline of 1+N requests to Squid using a
9376 single connection, without waiting for Squid to respond to the first
9377 of those requests. This option limits the number of concurrent
9378 requests Squid will try to handle in parallel. If set to N, Squid
9379 will try to receive and process up to 1+N requests on the same
9380 connection concurrently.
9382 Defaults to 0 (off) for bandwidth management and access logging
9385 NOTE: pipelining requires persistent connections to clients.
9387 WARNING: pipelining breaks NTLM and Negotiate/Kerberos authentication.
9390 NAME: high_response_time_warning
9393 LOC: Config.warnings.high_rptm
9395 DEFAULT_DOC: disabled.
9397 If the one-minute median response time exceeds this value,
9398 Squid prints a WARNING with debug level 0 to get the
9399 administrators attention. The value is in milliseconds.
9402 NAME: high_page_fault_warning
9404 LOC: Config.warnings.high_pf
9406 DEFAULT_DOC: disabled.
9408 If the one-minute average page fault rate exceeds this
9409 value, Squid prints a WARNING with debug level 0 to get
9410 the administrators attention. The value is in page faults
9414 NAME: high_memory_warning
9416 LOC: Config.warnings.high_memory
9417 IFDEF: HAVE_MSTATS&&HAVE_GNUMALLOC_H
9419 DEFAULT_DOC: disabled.
9421 If the memory usage (as determined by gnumalloc, if available and used)
9422 exceeds this amount, Squid prints a WARNING with debug level 0 to get
9423 the administrators attention.
9425 # TODO: link high_memory_warning to mempools?
9427 NAME: sleep_after_fork
9428 COMMENT: (microseconds)
9430 LOC: Config.sleep_after_fork
9433 When this is set to a non-zero value, the main Squid process
9434 sleeps the specified number of microseconds after a fork()
9435 system call. This sleep may help the situation where your
9436 system reports fork() failures due to lack of (virtual)
9437 memory. Note, however, if you have a lot of child
9438 processes, these sleep delays will add up and your
9439 Squid will not service requests for some amount of time
9440 until all the child processes have been started.
9441 On Windows value less then 1000 (1 milliseconds) are
9445 NAME: windows_ipaddrchangemonitor
9446 IFDEF: _SQUID_WINDOWS_
9450 LOC: Config.onoff.WIN32_IpAddrChangeMonitor
9452 On Windows Squid by default will monitor IP address changes and will
9453 reconfigure itself after any detected event. This is very useful for
9454 proxies connected to internet with dial-up interfaces.
9455 In some cases (a Proxy server acting as VPN gateway is one) it could be
9456 desiderable to disable this behaviour setting this to 'off'.
9457 Note: after changing this, Squid service must be restarted.
9462 IFDEF: USE_SQUID_EUI
9464 LOC: Eui::TheConfig.euiLookup
9466 Whether to lookup the EUI or MAC address of a connected client.
9469 NAME: max_filedescriptors max_filedesc
9472 DEFAULT_DOC: Use operating system limits set by ulimit.
9473 LOC: Config.max_filedescriptors
9475 Reduce the maximum number of filedescriptors supported below
9476 the usual operating system defaults.
9478 Remove from squid.conf to inherit the current ulimit setting.
9480 Note: Changing this requires a restart of Squid. Also
9481 not all I/O types supports large values (eg on Windows).
9484 NAME: force_request_body_continuation
9486 LOC: Config.accessList.forceRequestBodyContinuation
9488 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
9490 This option controls how Squid handles data upload requests from HTTP
9491 and FTP agents that require a "Please Continue" control message response
9492 to actually send the request body to Squid. It is mostly useful in
9493 adaptation environments.
9495 When Squid receives an HTTP request with an "Expect: 100-continue"
9496 header or an FTP upload command (e.g., STOR), Squid normally sends the
9497 request headers or FTP command information to an adaptation service (or
9498 peer) and waits for a response. Most adaptation services (and some
9499 broken peers) may not respond to Squid at that stage because they may
9500 decide to wait for the HTTP request body or FTP data transfer. However,
9501 that request body or data transfer may never come because Squid has not
9502 responded with the HTTP 100 or FTP 150 (Please Continue) control message
9503 to the request sender yet!
9505 An allow match tells Squid to respond with the HTTP 100 or FTP 150
9506 (Please Continue) control message on its own, before forwarding the
9507 request to an adaptation service or peer. Such a response usually forces
9508 the request sender to proceed with sending the body. A deny match tells
9509 Squid to delay that control response until the origin server confirms
9510 that the request body is needed. Delaying is the default behavior.
projects / thirdparty / squid.git / blob