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 cafile= File containing additional CA certificates to
1939 use when verifying client certificates. If unset
1940 clientca will be used.
1942 capath= Directory containing additional CA certificates
1943 and CRL lists to use when verifying client certificates.
1945 crlfile= File of additional CRL lists to use when verifying
1946 the client certificate, in addition to CRLs stored in
1947 the capath. Implies VERIFY_CRL flag below.
1950 File containing DH parameters for temporary/ephemeral DH key
1951 exchanges, optionally prefixed by a curve for ephemeral ECDH
1953 See OpenSSL documentation for details on how to create the
1954 DH parameter file. Supported curves for ECDH can be listed
1955 using the "openssl ecparam -list_curves" command.
1956 WARNING: EDH and EECDH ciphers will be silently disabled if
1957 this option is not set.
1959 sslflags= Various flags modifying the use of SSL:
1961 Don't request client certificates
1962 immediately, but wait until acl processing
1963 requires a certificate (not yet implemented).
1965 Don't use the default CA lists built in
1968 Don't allow for session reuse. Each connection
1969 will result in a new SSL session.
1971 Verify CRL lists when accepting client
1974 Verify CRL lists for all certificates in the
1975 client certificate chain.
1977 sslcontext= SSL session ID context identifier.
1981 connection-auth[=on|off]
1982 use connection-auth=off to tell Squid to prevent
1983 forwarding Microsoft connection oriented authentication
1984 (NTLM, Negotiate and Kerberos)
1986 disable-pmtu-discovery=
1987 Control Path-MTU discovery usage:
1988 off lets OS decide on what to do (default).
1989 transparent disable PMTU discovery when transparent
1991 always disable always PMTU discovery.
1993 In many setups of transparently intercepting proxies
1994 Path-MTU discovery can not work on traffic towards the
1995 clients. This is the case when the intercepting device
1996 does not fully track connections and fails to forward
1997 ICMP must fragment messages to the cache server. If you
1998 have such setup and experience that certain clients
1999 sporadically hang or never complete requests set
2000 disable-pmtu-discovery option to 'transparent'.
2002 name= Specifies a internal name for the port. Defaults to
2003 the port specification (port or addr:port)
2005 tcpkeepalive[=idle,interval,timeout]
2006 Enable TCP keepalive probes of idle connections.
2007 In seconds; idle is the initial time before TCP starts
2008 probing the connection, interval how often to probe, and
2009 timeout the time before giving up.
2011 require-proxy-header
2012 Require PROXY protocol version 1 or 2 connections.
2013 The proxy_protocol_access is required to whitelist
2014 downstream proxies which can be trusted.
2016 If you run Squid on a dual-homed machine with an internal
2017 and an external interface we recommend you to specify the
2018 internal address:port in http_port. This way Squid will only be
2019 visible on the internal address.
2023 # Squid normally listens to port 3128
2024 http_port @DEFAULT_HTTP_PORT@
2034 Usage: [ip:]port cert=certificate.pem [key=key.pem] [mode] [options...]
2036 The socket address where Squid will listen for client requests made
2037 over TLS or SSL connections. Commonly referred to as HTTPS.
2039 This is most useful for situations where you are running squid in
2040 accelerator mode and you want to do the SSL work at the accelerator level.
2042 You may specify multiple socket addresses on multiple lines,
2043 each with their own SSL certificate and/or options.
2047 accel Accelerator / reverse proxy mode
2049 intercept Support for IP-Layer interception of
2050 outgoing requests without browser settings.
2051 NP: disables authentication and IPv6 on the port.
2053 tproxy Support Linux TPROXY for spoofing outgoing
2054 connections using the client IP address.
2055 NP: disables authentication and maybe IPv6 on the port.
2057 ssl-bump For each intercepted connection allowed by ssl_bump
2058 ACLs, establish a secure connection with the client and with
2059 the server, decrypt HTTPS messages as they pass through
2060 Squid, and treat them as unencrypted HTTP messages,
2061 becoming the man-in-the-middle.
2063 An "ssl_bump server-first" match is required to
2064 fully enable bumping of intercepted SSL connections.
2066 Requires tproxy or intercept.
2068 Omitting the mode flag causes default forward proxy mode to be used.
2071 See http_port for a list of generic options
2076 cert= Path to SSL certificate (PEM format).
2078 key= Path to SSL private key file (PEM format)
2079 if not specified, the certificate file is
2080 assumed to be a combined certificate and
2083 cipher= Colon separated list of supported ciphers.
2085 options= Various SSL engine options. The most important
2088 NO_SSLv3 Disallow the use of SSLv3
2090 NO_TLSv1 Disallow the use of TLSv1.0
2092 NO_TLSv1_1 Disallow the use of TLSv1.1
2094 NO_TLSv1_2 Disallow the use of TLSv1.2
2097 Always create a new key when using
2098 temporary/ephemeral DH key exchanges
2101 Enable ephemeral ECDH key exchange.
2102 The adopted curve should be specified
2103 using the tls-dh option.
2106 Disable use of RFC5077 session tickets.
2107 Some servers may have problems
2108 understanding the TLS extension due
2109 to ambiguous specification in RFC4507.
2111 ALL Enable various bug workarounds
2112 suggested as "harmless" by OpenSSL
2113 Be warned that this reduces SSL/TLS
2114 strength to some attacks.
2116 See the OpenSSL SSL_CTX_set_options documentation for a
2119 clientca= File containing the list of CAs to use when
2120 requesting a client certificate.
2122 cafile= File containing additional CA certificates to
2123 use when verifying client certificates. If unset
2124 clientca will be used.
2126 capath= Directory containing additional CA certificates
2127 and CRL lists to use when verifying client certificates.
2129 crlfile= File of additional CRL lists to use when verifying
2130 the client certificate, in addition to CRLs stored in
2131 the capath. Implies VERIFY_CRL flag below.
2134 File containing DH parameters for temporary/ephemeral DH key
2135 exchanges, optionally prefixed by a curve for ephemeral ECDH
2138 sslflags= Various flags modifying the use of SSL:
2140 Don't request client certificates
2141 immediately, but wait until acl processing
2142 requires a certificate (not yet implemented).
2144 Don't use the default CA lists built in
2147 Don't allow for session reuse. Each connection
2148 will result in a new SSL session.
2150 Verify CRL lists when accepting client
2153 Verify CRL lists for all certificates in the
2154 client certificate chain.
2156 sslcontext= SSL session ID context identifier.
2158 generate-host-certificates[=<on|off>]
2159 Dynamically create SSL server certificates for the
2160 destination hosts of bumped SSL requests.When
2161 enabled, the cert and key options are used to sign
2162 generated certificates. Otherwise generated
2163 certificate will be selfsigned.
2164 If there is CA certificate life time of generated
2165 certificate equals lifetime of CA certificate. If
2166 generated certificate is selfsigned lifetime is three
2168 This option is enabled by default when SslBump is used.
2169 See the sslBump option above for more information.
2171 dynamic_cert_mem_cache_size=SIZE
2172 Approximate total RAM size spent on cached generated
2173 certificates. If set to zero, caching is disabled. The
2174 default value is 4MB.
2176 See http_port for a list of available options.
2184 Enables Native FTP proxy by specifying the socket address where Squid
2185 listens for FTP client requests. See http_port directive for various
2186 ways to specify the listening address and mode.
2188 Usage: ftp_port address [mode] [options]
2190 WARNING: This is a new, experimental, complex feature that has seen
2191 limited production exposure. Some Squid modules (e.g., caching) do not
2192 currently work with native FTP proxying, and many features have not
2193 even been tested for compatibility. Test well before deploying!
2195 Native FTP proxying differs substantially from proxying HTTP requests
2196 with ftp:// URIs because Squid works as an FTP server and receives
2197 actual FTP commands (rather than HTTP requests with FTP URLs).
2199 Native FTP commands accepted at ftp_port are internally converted or
2200 wrapped into HTTP-like messages. The same happens to Native FTP
2201 responses received from FTP origin servers. Those HTTP-like messages
2202 are shoveled through regular access control and adaptation layers
2203 between the FTP client and the FTP origin server. This allows Squid to
2204 examine, adapt, block, and log FTP exchanges. Squid reuses most HTTP
2205 mechanisms when shoveling wrapped FTP messages. For example,
2206 http_access and adaptation_access directives are used.
2210 intercept Same as http_port intercept. The FTP origin address is
2211 determined based on the intended destination of the
2212 intercepted connection.
2214 tproxy Support Linux TPROXY for spoofing outgoing
2215 connections using the client IP address.
2216 NP: disables authentication and maybe IPv6 on the port.
2218 By default (i.e., without an explicit mode option), Squid extracts the
2219 FTP origin address from the login@origin parameter of the FTP USER
2220 command. Many popular FTP clients support such native FTP proxying.
2224 name=token Specifies an internal name for the port. Defaults to
2225 the port address. Usable with myportname ACL.
2228 Enables tracking of FTP directories by injecting extra
2229 PWD commands and adjusting Request-URI (in wrapping
2230 HTTP requests) to reflect the current FTP server
2231 directory. Tracking is disabled by default.
2233 protocol=FTP Protocol to reconstruct accelerated and intercepted
2234 requests with. Defaults to FTP. No other accepted
2235 values have been tested with. An unsupported value
2236 results in a FATAL error. Accepted values are FTP,
2237 HTTP (or HTTP/1.1), and HTTPS (or HTTPS/1.1).
2239 Other http_port modes and options that are not specific to HTTP and
2240 HTTPS may also work.
2243 NAME: tcp_outgoing_tos tcp_outgoing_ds tcp_outgoing_dscp
2246 LOC: Ip::Qos::TheConfig.tosToServer
2248 Allows you to select a TOS/Diffserv value for packets outgoing
2249 on the server side, based on an ACL.
2251 tcp_outgoing_tos ds-field [!]aclname ...
2253 Example where normal_service_net uses the TOS value 0x00
2254 and good_service_net uses 0x20
2256 acl normal_service_net src 10.0.0.0/24
2257 acl good_service_net src 10.0.1.0/24
2258 tcp_outgoing_tos 0x00 normal_service_net
2259 tcp_outgoing_tos 0x20 good_service_net
2261 TOS/DSCP values really only have local significance - so you should
2262 know what you're specifying. For more information, see RFC2474,
2263 RFC2475, and RFC3260.
2265 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
2266 "default" to use whatever default your host has.
2267 Note that only multiples of 4 are usable as the two rightmost bits have
2268 been redefined for use by ECN (RFC 3168 section 23.1).
2269 The squid parser will enforce this by masking away the ECN bits.
2271 Processing proceeds in the order specified, and stops at first fully
2274 Only fast ACLs are supported.
2277 NAME: clientside_tos
2280 LOC: Ip::Qos::TheConfig.tosToClient
2282 Allows you to select a TOS/DSCP value for packets being transmitted
2283 on the client-side, based on an ACL.
2285 clientside_tos ds-field [!]aclname ...
2287 Example where normal_service_net uses the TOS value 0x00
2288 and good_service_net uses 0x20
2290 acl normal_service_net src 10.0.0.0/24
2291 acl good_service_net src 10.0.1.0/24
2292 clientside_tos 0x00 normal_service_net
2293 clientside_tos 0x20 good_service_net
2295 Note: This feature is incompatible with qos_flows. Any TOS values set here
2296 will be overwritten by TOS values in qos_flows.
2298 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
2299 "default" to use whatever default your host has.
2300 Note that only multiples of 4 are usable as the two rightmost bits have
2301 been redefined for use by ECN (RFC 3168 section 23.1).
2302 The squid parser will enforce this by masking away the ECN bits.
2306 NAME: tcp_outgoing_mark
2308 IFDEF: SO_MARK&&USE_LIBCAP
2310 LOC: Ip::Qos::TheConfig.nfmarkToServer
2312 Allows you to apply a Netfilter mark value to outgoing packets
2313 on the server side, based on an ACL.
2315 tcp_outgoing_mark mark-value [!]aclname ...
2317 Example where normal_service_net uses the mark value 0x00
2318 and good_service_net uses 0x20
2320 acl normal_service_net src 10.0.0.0/24
2321 acl good_service_net src 10.0.1.0/24
2322 tcp_outgoing_mark 0x00 normal_service_net
2323 tcp_outgoing_mark 0x20 good_service_net
2325 Only fast ACLs are supported.
2328 NAME: clientside_mark
2330 IFDEF: SO_MARK&&USE_LIBCAP
2332 LOC: Ip::Qos::TheConfig.nfmarkToClient
2334 Allows you to apply a Netfilter mark value to packets being transmitted
2335 on the client-side, based on an ACL.
2337 clientside_mark mark-value [!]aclname ...
2339 Example where normal_service_net uses the mark value 0x00
2340 and good_service_net uses 0x20
2342 acl normal_service_net src 10.0.0.0/24
2343 acl good_service_net src 10.0.1.0/24
2344 clientside_mark 0x00 normal_service_net
2345 clientside_mark 0x20 good_service_net
2347 Note: This feature is incompatible with qos_flows. Any mark values set here
2348 will be overwritten by mark values in qos_flows.
2355 LOC: Ip::Qos::TheConfig
2357 Allows you to select a TOS/DSCP value to mark outgoing
2358 connections to the client, based on where the reply was sourced.
2359 For platforms using netfilter, allows you to set a netfilter mark
2360 value instead of, or in addition to, a TOS value.
2362 By default this functionality is disabled. To enable it with the default
2363 settings simply use "qos_flows mark" or "qos_flows tos". Default
2364 settings will result in the netfilter mark or TOS value being copied
2365 from the upstream connection to the client. Note that it is the connection
2366 CONNMARK value not the packet MARK value that is copied.
2368 It is not currently possible to copy the mark or TOS value from the
2369 client to the upstream connection request.
2371 TOS values really only have local significance - so you should
2372 know what you're specifying. For more information, see RFC2474,
2373 RFC2475, and RFC3260.
2375 The TOS/DSCP byte must be exactly that - a octet value 0 - 255.
2376 Note that only multiples of 4 are usable as the two rightmost bits have
2377 been redefined for use by ECN (RFC 3168 section 23.1).
2378 The squid parser will enforce this by masking away the ECN bits.
2380 Mark values can be any unsigned 32-bit integer value.
2382 This setting is configured by setting the following values:
2384 tos|mark Whether to set TOS or netfilter mark values
2386 local-hit=0xFF Value to mark local cache hits.
2388 sibling-hit=0xFF Value to mark hits from sibling peers.
2390 parent-hit=0xFF Value to mark hits from parent peers.
2392 miss=0xFF[/mask] Value to mark cache misses. Takes precedence
2393 over the preserve-miss feature (see below), unless
2394 mask is specified, in which case only the bits
2395 specified in the mask are written.
2397 The TOS variant of the following features are only possible on Linux
2398 and require your kernel to be patched with the TOS preserving ZPH
2399 patch, available from http://zph.bratcheda.org
2400 No patch is needed to preserve the netfilter mark, which will work
2401 with all variants of netfilter.
2403 disable-preserve-miss
2404 This option disables the preservation of the TOS or netfilter
2405 mark. By default, the existing TOS or netfilter mark value of
2406 the response coming from the remote server will be retained
2407 and masked with miss-mark.
2408 NOTE: in the case of a netfilter mark, the mark must be set on
2409 the connection (using the CONNMARK target) not on the packet
2413 Allows you to mask certain bits in the TOS or mark value
2414 received from the remote server, before copying the value to
2415 the TOS sent towards clients.
2416 Default for tos: 0xFF (TOS from server is not changed).
2417 Default for mark: 0xFFFFFFFF (mark from server is not changed).
2419 All of these features require the --enable-zph-qos compilation flag
2420 (enabled by default). Netfilter marking also requires the
2421 libnetfilter_conntrack libraries (--with-netfilter-conntrack) and
2422 libcap 2.09+ (--with-libcap).
2426 NAME: tcp_outgoing_address
2429 DEFAULT_DOC: Address selection is performed by the operating system.
2430 LOC: Config.accessList.outgoing_address
2432 Allows you to map requests to different outgoing IP addresses
2433 based on the username or source address of the user making
2436 tcp_outgoing_address ipaddr [[!]aclname] ...
2439 Forwarding clients with dedicated IPs for certain subnets.
2441 acl normal_service_net src 10.0.0.0/24
2442 acl good_service_net src 10.0.2.0/24
2444 tcp_outgoing_address 2001:db8::c001 good_service_net
2445 tcp_outgoing_address 10.1.0.2 good_service_net
2447 tcp_outgoing_address 2001:db8::beef normal_service_net
2448 tcp_outgoing_address 10.1.0.1 normal_service_net
2450 tcp_outgoing_address 2001:db8::1
2451 tcp_outgoing_address 10.1.0.3
2453 Processing proceeds in the order specified, and stops at first fully
2456 Squid will add an implicit IP version test to each line.
2457 Requests going to IPv4 websites will use the outgoing 10.1.0.* addresses.
2458 Requests going to IPv6 websites will use the outgoing 2001:db8:* addresses.
2461 NOTE: The use of this directive using client dependent ACLs is
2462 incompatible with the use of server side persistent connections. To
2463 ensure correct results it is best to set server_persistent_connections
2464 to off when using this directive in such configurations.
2466 NOTE: The use of this directive to set a local IP on outgoing TCP links
2467 is incompatible with using TPROXY to set client IP out outbound TCP links.
2468 When needing to contact peers use the no-tproxy cache_peer option and the
2469 client_dst_passthru directive re-enable normal forwarding such as this.
2473 NAME: host_verify_strict
2476 LOC: Config.onoff.hostStrictVerify
2478 Regardless of this option setting, when dealing with intercepted
2479 traffic, Squid always verifies that the destination IP address matches
2480 the Host header domain or IP (called 'authority form URL').
2482 This enforcement is performed to satisfy a MUST-level requirement in
2483 RFC 2616 section 14.23: "The Host field value MUST represent the naming
2484 authority of the origin server or gateway given by the original URL".
2487 Squid always responds with an HTTP 409 (Conflict) error
2488 page and logs a security warning if there is no match.
2490 Squid verifies that the destination IP address matches
2491 the Host header for forward-proxy and reverse-proxy traffic
2492 as well. For those traffic types, Squid also enables the
2493 following checks, comparing the corresponding Host header
2494 and Request-URI components:
2496 * The host names (domain or IP) must be identical,
2497 but valueless or missing Host header disables all checks.
2498 For the two host names to match, both must be either IP
2501 * Port numbers must be identical, but if a port is missing
2502 the scheme-default port is assumed.
2505 When set to OFF (the default):
2506 Squid allows suspicious requests to continue but logs a
2507 security warning and blocks caching of the response.
2509 * Forward-proxy traffic is not checked at all.
2511 * Reverse-proxy traffic is not checked at all.
2513 * Intercepted traffic which passes verification is handled
2514 according to client_dst_passthru.
2516 * Intercepted requests which fail verification are sent
2517 to the client original destination instead of DIRECT.
2518 This overrides 'client_dst_passthru off'.
2520 For now suspicious intercepted CONNECT requests are always
2521 responded to with an HTTP 409 (Conflict) error page.
2526 As described in CVE-2009-0801 when the Host: header alone is used
2527 to determine the destination of a request it becomes trivial for
2528 malicious scripts on remote websites to bypass browser same-origin
2529 security policy and sandboxing protections.
2531 The cause of this is that such applets are allowed to perform their
2532 own HTTP stack, in which case the same-origin policy of the browser
2533 sandbox only verifies that the applet tries to contact the same IP
2534 as from where it was loaded at the IP level. The Host: header may
2535 be different from the connected IP and approved origin.
2539 NAME: client_dst_passthru
2542 LOC: Config.onoff.client_dst_passthru
2544 With NAT or TPROXY intercepted traffic Squid may pass the request
2545 directly to the original client destination IP or seek a faster
2546 source using the HTTP Host header.
2548 Using Host to locate alternative servers can provide faster
2549 connectivity with a range of failure recovery options.
2550 But can also lead to connectivity trouble when the client and
2551 server are attempting stateful interactions unaware of the proxy.
2553 This option (on by default) prevents alternative DNS entries being
2554 located to send intercepted traffic DIRECT to an origin server.
2555 The clients original destination IP and port will be used instead.
2557 Regardless of this option setting, when dealing with intercepted
2558 traffic Squid will verify the Host: header and any traffic which
2559 fails Host verification will be treated as if this option were ON.
2561 see host_verify_strict for details on the verification process.
2566 -----------------------------------------------------------------------------
2569 NAME: tls_outgoing_options
2570 IFDEF: USE_GNUTLS||USE_OPENSSL
2571 TYPE: securePeerOptions
2572 DEFAULT: min-version=1.0
2573 LOC: Security::ProxyOutgoingConfig
2575 disable Do not support https:// URLs.
2577 cert=/path/to/client/certificate
2578 A client TLS certificate to use when connecting.
2580 key=/path/to/client/private_key
2581 The private TLS key corresponding to the cert= above.
2582 If key= is not specified cert= is assumed to reference
2583 a PEM file containing both the certificate and the key.
2585 cipher=... The list of valid TLS ciphers to use.
2588 The minimum TLS protocol version to permit.
2589 To control SSLv3 use the options= parameter.
2590 Supported Values: 1.0 (default), 1.1, 1.2
2592 options=... Specify various TLS/SSL implementation options:
2594 NO_SSLv3 Disallow the use of SSLv3
2596 NO_TLSv1 Disallow the use of TLSv1.0
2598 NO_TLSv1_1 Disallow the use of TLSv1.1
2600 NO_TLSv1_2 Disallow the use of TLSv1.2
2603 Always create a new key when using
2604 temporary/ephemeral DH key exchanges
2607 Disable use of RFC5077 session tickets.
2608 Some servers may have problems
2609 understanding the TLS extension due
2610 to ambiguous specification in RFC4507.
2612 ALL Enable various bug workarounds
2613 suggested as "harmless" by OpenSSL
2614 Be warned that this reduces SSL/TLS
2615 strength to some attacks.
2617 See the OpenSSL SSL_CTX_set_options documentation for a
2620 cafile=... A file containing additional CA certificates to use
2621 when verifying the peer certificate.
2623 capath=... A directory containing additional CA certificates to
2624 use when verifying the peer certificate.
2626 crlfile=... A certificate revocation list file to use when
2627 verifying the peer certificate.
2629 flags=... Specify various flags modifying the TLS implementation:
2632 Accept certificates even if they fail to
2635 Don't use the default CA list built in
2638 Don't verify the peer certificate
2639 matches the server name
2641 domain= The peer name as advertised in its certificate.
2642 Used for verifying the correctness of the received peer
2643 certificate. If not specified the peer hostname will be
2649 -----------------------------------------------------------------------------
2652 NAME: ssl_unclean_shutdown
2656 LOC: Config.SSL.unclean_shutdown
2658 Some browsers (especially MSIE) bugs out on SSL shutdown
2665 LOC: Config.SSL.ssl_engine
2668 The OpenSSL engine to use. You will need to set this if you
2669 would like to use hardware SSL acceleration for example.
2672 NAME: sslproxy_session_ttl
2675 LOC: Config.SSL.session_ttl
2678 Sets the timeout value for SSL sessions
2681 NAME: sslproxy_session_cache_size
2684 LOC: Config.SSL.sessionCacheSize
2687 Sets the cache size to use for ssl session
2690 NAME: sslproxy_cert_sign_hash
2693 LOC: Config.SSL.certSignHash
2696 Sets the hashing algorithm to use when signing generated certificates.
2697 Valid algorithm names depend on the OpenSSL library used. The following
2698 names are usually available: sha1, sha256, sha512, and md5. Please see
2699 your OpenSSL library manual for the available hashes. By default, Squids
2700 that support this option use sha256 hashes.
2702 Squid does not forcefully purge cached certificates that were generated
2703 with an algorithm other than the currently configured one. They remain
2704 in the cache, subject to the regular cache eviction policy, and become
2705 useful if the algorithm changes again.
2710 TYPE: sslproxy_ssl_bump
2711 LOC: Config.accessList.ssl_bump
2712 DEFAULT_DOC: Become a TCP tunnel without decrypting proxied traffic.
2715 This option is consulted when a CONNECT request is received on
2716 an http_port (or a new connection is intercepted at an
2717 https_port), provided that port was configured with an ssl-bump
2718 flag. The subsequent data on the connection is either treated as
2719 HTTPS and decrypted OR tunneled at TCP level without decryption,
2720 depending on the first matching bumping "action".
2722 ssl_bump <action> [!]acl ...
2724 The following bumping actions are currently supported:
2727 Become a TCP tunnel without decrypting proxied traffic.
2728 This is the default action.
2731 Establish a secure connection with the server and, using a
2732 mimicked server certificate, with the client.
2735 Receive client (step SslBump1) or server (step SslBump2)
2736 certificate while preserving the possibility of splicing the
2737 connection. Peeking at the server certificate (during step 2)
2738 usually precludes bumping of the connection at step 3.
2741 Receive client (step SslBump1) or server (step SslBump2)
2742 certificate while preserving the possibility of bumping the
2743 connection. Staring at the server certificate (during step 2)
2744 usually precludes splicing of the connection at step 3.
2747 Close client and server connections.
2749 Backward compatibility actions available at step SslBump1:
2752 Bump the connection. Establish a secure connection with the
2753 client first, then connect to the server. This old mode does
2754 not allow Squid to mimic server SSL certificate and does not
2755 work with intercepted SSL connections.
2758 Bump the connection. Establish a secure connection with the
2759 server first, then establish a secure connection with the
2760 client, using a mimicked server certificate. Works with both
2761 CONNECT requests and intercepted SSL connections, but does
2762 not allow to make decisions based on SSL handshake info.
2765 Decide whether to bump or splice the connection based on
2766 client-to-squid and server-to-squid SSL hello messages.
2770 Same as the "splice" action.
2772 All ssl_bump rules are evaluated at each of the supported bumping
2773 steps. Rules with actions that are impossible at the current step are
2774 ignored. The first matching ssl_bump action wins and is applied at the
2775 end of the current step. If no rules match, the splice action is used.
2776 See the at_step ACL for a list of the supported SslBump steps.
2778 This clause supports both fast and slow acl types.
2779 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2781 See also: http_port ssl-bump, https_port ssl-bump, and acl at_step.
2784 # Example: Bump all requests except those originating from
2785 # localhost or those going to example.com.
2787 acl broken_sites dstdomain .example.com
2788 ssl_bump splice localhost
2789 ssl_bump splice broken_sites
2793 NAME: sslproxy_cert_error
2796 DEFAULT_DOC: Server certificate errors terminate the transaction.
2797 LOC: Config.ssl_client.cert_error
2800 Use this ACL to bypass server certificate validation errors.
2802 For example, the following lines will bypass all validation errors
2803 when talking to servers for example.com. All other
2804 validation errors will result in ERR_SECURE_CONNECT_FAIL error.
2806 acl BrokenButTrustedServers dstdomain example.com
2807 sslproxy_cert_error allow BrokenButTrustedServers
2808 sslproxy_cert_error deny all
2810 This clause only supports fast acl types.
2811 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2812 Using slow acl types may result in server crashes
2814 Without this option, all server certificate validation errors
2815 terminate the transaction to protect Squid and the client.
2817 SQUID_X509_V_ERR_INFINITE_VALIDATION error cannot be bypassed
2818 but should not happen unless your OpenSSL library is buggy.
2821 Bypassing validation errors is dangerous because an
2822 error usually implies that the server cannot be trusted
2823 and the connection may be insecure.
2825 See also: sslproxy_flags and DONT_VERIFY_PEER.
2828 NAME: sslproxy_cert_sign
2831 POSTSCRIPTUM: signUntrusted ssl::certUntrusted
2832 POSTSCRIPTUM: signSelf ssl::certSelfSigned
2833 POSTSCRIPTUM: signTrusted all
2834 TYPE: sslproxy_cert_sign
2835 LOC: Config.ssl_client.cert_sign
2838 sslproxy_cert_sign <signing algorithm> acl ...
2840 The following certificate signing algorithms are supported:
2843 Sign using the configured CA certificate which is usually
2844 placed in and trusted by end-user browsers. This is the
2845 default for trusted origin server certificates.
2848 Sign to guarantee an X509_V_ERR_CERT_UNTRUSTED browser error.
2849 This is the default for untrusted origin server certificates
2850 that are not self-signed (see ssl::certUntrusted).
2853 Sign using a self-signed certificate with the right CN to
2854 generate a X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT error in the
2855 browser. This is the default for self-signed origin server
2856 certificates (see ssl::certSelfSigned).
2858 This clause only supports fast acl types.
2860 When sslproxy_cert_sign acl(s) match, Squid uses the corresponding
2861 signing algorithm to generate the certificate and ignores all
2862 subsequent sslproxy_cert_sign options (the first match wins). If no
2863 acl(s) match, the default signing algorithm is determined by errors
2864 detected when obtaining and validating the origin server certificate.
2866 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2867 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2868 CONNECT request that carries a domain name. In all other cases (CONNECT
2869 to an IP address or an intercepted SSL connection), Squid cannot detect
2870 the domain mismatch at certificate generation time when
2871 bump-server-first is used.
2874 NAME: sslproxy_cert_adapt
2877 TYPE: sslproxy_cert_adapt
2878 LOC: Config.ssl_client.cert_adapt
2881 sslproxy_cert_adapt <adaptation algorithm> acl ...
2883 The following certificate adaptation algorithms are supported:
2886 Sets the "Not After" property to the "Not After" property of
2887 the CA certificate used to sign generated certificates.
2890 Sets the "Not Before" property to the "Not Before" property of
2891 the CA certificate used to sign generated certificates.
2893 setCommonName or setCommonName{CN}
2894 Sets Subject.CN property to the host name specified as a
2895 CN parameter or, if no explicit CN parameter was specified,
2896 extracted from the CONNECT request. It is a misconfiguration
2897 to use setCommonName without an explicit parameter for
2898 intercepted or tproxied SSL connections.
2900 This clause only supports fast acl types.
2902 Squid first groups sslproxy_cert_adapt options by adaptation algorithm.
2903 Within a group, when sslproxy_cert_adapt acl(s) match, Squid uses the
2904 corresponding adaptation algorithm to generate the certificate and
2905 ignores all subsequent sslproxy_cert_adapt options in that algorithm's
2906 group (i.e., the first match wins within each algorithm group). If no
2907 acl(s) match, the default mimicking action takes place.
2909 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2910 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2911 CONNECT request that carries a domain name. In all other cases (CONNECT
2912 to an IP address or an intercepted SSL connection), Squid cannot detect
2913 the domain mismatch at certificate generation time when
2914 bump-server-first is used.
2917 NAME: sslpassword_program
2920 LOC: Config.Program.ssl_password
2923 Specify a program used for entering SSL key passphrases
2924 when using encrypted SSL certificate keys. If not specified
2925 keys must either be unencrypted, or Squid started with the -N
2926 option to allow it to query interactively for the passphrase.
2928 The key file name is given as argument to the program allowing
2929 selection of the right password if you have multiple encrypted
2934 OPTIONS RELATING TO EXTERNAL SSL_CRTD
2935 -----------------------------------------------------------------------------
2938 NAME: sslcrtd_program
2941 DEFAULT: @DEFAULT_SSL_CRTD@ -s @DEFAULT_SSL_DB_DIR@ -M 4MB
2942 LOC: Ssl::TheConfig.ssl_crtd
2944 Specify the location and options of the executable for ssl_crtd process.
2945 @DEFAULT_SSL_CRTD@ program requires -s and -M parameters
2946 For more information use:
2947 @DEFAULT_SSL_CRTD@ -h
2950 NAME: sslcrtd_children
2951 TYPE: HelperChildConfig
2953 DEFAULT: 32 startup=5 idle=1
2954 LOC: Ssl::TheConfig.ssl_crtdChildren
2956 The maximum number of processes spawn to service ssl server.
2957 The maximum this may be safely set to is 32.
2959 The startup= and idle= options allow some measure of skew in your
2964 Sets the minimum number of processes to spawn when Squid
2965 starts or reconfigures. When set to zero the first request will
2966 cause spawning of the first child process to handle it.
2968 Starting too few children temporary slows Squid under load while it
2969 tries to spawn enough additional processes to cope with traffic.
2973 Sets a minimum of how many processes Squid is to try and keep available
2974 at all times. When traffic begins to rise above what the existing
2975 processes can handle this many more will be spawned up to the maximum
2976 configured. A minimum setting of 1 is required.
2980 Sets the maximum number of queued requests.
2981 If the queued requests exceed queue size for more than 3 minutes
2982 squid aborts its operation.
2983 The default value is set to 2*numberofchildren.
2985 You must have at least one ssl_crtd process.
2988 NAME: sslcrtvalidator_program
2992 LOC: Ssl::TheConfig.ssl_crt_validator
2994 Specify the location and options of the executable for ssl_crt_validator
2997 Usage: sslcrtvalidator_program [ttl=n] [cache=n] path ...
3000 ttl=n TTL in seconds for cached results. The default is 60 secs
3001 cache=n limit the result cache size. The default value is 2048
3004 NAME: sslcrtvalidator_children
3005 TYPE: HelperChildConfig
3007 DEFAULT: 32 startup=5 idle=1 concurrency=1
3008 LOC: Ssl::TheConfig.ssl_crt_validator_Children
3010 The maximum number of processes spawn to service SSL server.
3011 The maximum this may be safely set to is 32.
3013 The startup= and idle= options allow some measure of skew in your
3018 Sets the minimum number of processes to spawn when Squid
3019 starts or reconfigures. When set to zero the first request will
3020 cause spawning of the first child process to handle it.
3022 Starting too few children temporary slows Squid under load while it
3023 tries to spawn enough additional processes to cope with traffic.
3027 Sets a minimum of how many processes Squid is to try and keep available
3028 at all times. When traffic begins to rise above what the existing
3029 processes can handle this many more will be spawned up to the maximum
3030 configured. A minimum setting of 1 is required.
3034 The number of requests each certificate validator helper can handle in
3035 parallel. A value of 0 indicates the certficate validator does not
3036 support concurrency. Defaults to 1.
3038 When this directive is set to a value >= 1 then the protocol
3039 used to communicate with the helper is modified to include
3040 a request ID in front of the request/response. The request
3041 ID from the request must be echoed back with the response
3046 Sets the maximum number of queued requests.
3047 If the queued requests exceed queue size for more than 3 minutes
3048 squid aborts its operation.
3049 The default value is set to 2*numberofchildren.
3051 You must have at least one ssl_crt_validator process.
3055 OPTIONS WHICH AFFECT THE NEIGHBOR SELECTION ALGORITHM
3056 -----------------------------------------------------------------------------
3064 To specify other caches in a hierarchy, use the format:
3066 cache_peer hostname type http-port icp-port [options]
3071 # hostname type port port options
3072 # -------------------- -------- ----- ----- -----------
3073 cache_peer parent.foo.net parent 3128 3130 default
3074 cache_peer sib1.foo.net sibling 3128 3130 proxy-only
3075 cache_peer sib2.foo.net sibling 3128 3130 proxy-only
3076 cache_peer example.com parent 80 0 default
3077 cache_peer cdn.example.com sibling 3128 0
3079 type: either 'parent', 'sibling', or 'multicast'.
3081 proxy-port: The port number where the peer accept HTTP requests.
3082 For other Squid proxies this is usually 3128
3083 For web servers this is usually 80
3085 icp-port: Used for querying neighbor caches about objects.
3086 Set to 0 if the peer does not support ICP or HTCP.
3087 See ICP and HTCP options below for additional details.
3090 ==== ICP OPTIONS ====
3092 You MUST also set icp_port and icp_access explicitly when using these options.
3093 The defaults will prevent peer traffic using ICP.
3096 no-query Disable ICP queries to this neighbor.
3099 Indicates the named peer is a member of a multicast group.
3100 ICP queries will not be sent directly to the peer, but ICP
3101 replies will be accepted from it.
3103 closest-only Indicates that, for ICP_OP_MISS replies, we'll only forward
3104 CLOSEST_PARENT_MISSes and never FIRST_PARENT_MISSes.
3107 To only send ICP queries to this neighbor infrequently.
3108 This is used to keep the neighbor round trip time updated
3109 and is usually used in conjunction with weighted-round-robin.
3112 ==== HTCP OPTIONS ====
3114 You MUST also set htcp_port and htcp_access explicitly when using these options.
3115 The defaults will prevent peer traffic using HTCP.
3118 htcp Send HTCP, instead of ICP, queries to the neighbor.
3119 You probably also want to set the "icp-port" to 4827
3120 instead of 3130. This directive accepts a comma separated
3121 list of options described below.
3123 htcp=oldsquid Send HTCP to old Squid versions (2.5 or earlier).
3125 htcp=no-clr Send HTCP to the neighbor but without
3126 sending any CLR requests. This cannot be used with
3129 htcp=only-clr Send HTCP to the neighbor but ONLY CLR requests.
3130 This cannot be used with no-clr.
3133 Send HTCP to the neighbor including CLRs but only when
3134 they do not result from PURGE requests.
3137 Forward any HTCP CLR requests this proxy receives to the peer.
3140 ==== PEER SELECTION METHODS ====
3142 The default peer selection method is ICP, with the first responding peer
3143 being used as source. These options can be used for better load balancing.
3146 default This is a parent cache which can be used as a "last-resort"
3147 if a peer cannot be located by any of the peer-selection methods.
3148 If specified more than once, only the first is used.
3150 round-robin Load-Balance parents which should be used in a round-robin
3151 fashion in the absence of any ICP queries.
3152 weight=N can be used to add bias.
3154 weighted-round-robin
3155 Load-Balance parents which should be used in a round-robin
3156 fashion with the frequency of each parent being based on the
3157 round trip time. Closer parents are used more often.
3158 Usually used for background-ping parents.
3159 weight=N can be used to add bias.
3161 carp Load-Balance parents which should be used as a CARP array.
3162 The requests will be distributed among the parents based on the
3163 CARP load balancing hash function based on their weight.
3165 userhash Load-balance parents based on the client proxy_auth or ident username.
3167 sourcehash Load-balance parents based on the client source IP.
3170 To be used only for cache peers of type "multicast".
3171 ALL members of this multicast group have "sibling"
3172 relationship with it, not "parent". This is to a multicast
3173 group when the requested object would be fetched only from
3174 a "parent" cache, anyway. It's useful, e.g., when
3175 configuring a pool of redundant Squid proxies, being
3176 members of the same multicast group.
3179 ==== PEER SELECTION OPTIONS ====
3181 weight=N use to affect the selection of a peer during any weighted
3182 peer-selection mechanisms.
3183 The weight must be an integer; default is 1,
3184 larger weights are favored more.
3185 This option does not affect parent selection if a peering
3186 protocol is not in use.
3188 basetime=N Specify a base amount to be subtracted from round trip
3190 It is subtracted before division by weight in calculating
3191 which parent to fectch from. If the rtt is less than the
3192 base time the rtt is set to a minimal value.
3194 ttl=N Specify a TTL to use when sending multicast ICP queries
3196 Only useful when sending to a multicast group.
3197 Because we don't accept ICP replies from random
3198 hosts, you must configure other group members as
3199 peers with the 'multicast-responder' option.
3201 no-delay To prevent access to this neighbor from influencing the
3204 digest-url=URL Tell Squid to fetch the cache digest (if digests are
3205 enabled) for this host from the specified URL rather
3206 than the Squid default location.
3209 ==== CARP OPTIONS ====
3211 carp-key=key-specification
3212 use a different key than the full URL to hash against the peer.
3213 the key-specification is a comma-separated list of the keywords
3214 scheme, host, port, path, params
3215 Order is not important.
3217 ==== ACCELERATOR / REVERSE-PROXY OPTIONS ====
3219 originserver Causes this parent to be contacted as an origin server.
3220 Meant to be used in accelerator setups when the peer
3224 Set the Host header of requests forwarded to this peer.
3225 Useful in accelerator setups where the server (peer)
3226 expects a certain domain name but clients may request
3227 others. ie example.com or www.example.com
3229 no-digest Disable request of cache digests.
3232 Disables requesting ICMP RTT database (NetDB).
3235 ==== AUTHENTICATION OPTIONS ====
3238 If this is a personal/workgroup proxy and your parent
3239 requires proxy authentication.
3241 Note: The string can include URL escapes (i.e. %20 for
3242 spaces). This also means % must be written as %%.
3245 Send login details received from client to this peer.
3246 Both Proxy- and WWW-Authorization headers are passed
3247 without alteration to the peer.
3248 Authentication is not required by Squid for this to work.
3250 Note: This will pass any form of authentication but
3251 only Basic auth will work through a proxy unless the
3252 connection-auth options are also used.
3254 login=PASS Send login details received from client to this peer.
3255 Authentication is not required by this option.
3257 If there are no client-provided authentication headers
3258 to pass on, but username and password are available
3259 from an external ACL user= and password= result tags
3260 they may be sent instead.
3262 Note: To combine this with proxy_auth both proxies must
3263 share the same user database as HTTP only allows for
3264 a single login (one for proxy, one for origin server).
3265 Also be warned this will expose your users proxy
3266 password to the peer. USE WITH CAUTION
3269 Send the username to the upstream cache, but with a
3270 fixed password. This is meant to be used when the peer
3271 is in another administrative domain, but it is still
3272 needed to identify each user.
3273 The star can optionally be followed by some extra
3274 information which is added to the username. This can
3275 be used to identify this proxy to the peer, similar to
3276 the login=username:password option above.
3279 If this is a personal/workgroup proxy and your parent
3280 requires a secure proxy authentication.
3281 The first principal from the default keytab or defined by
3282 the environment variable KRB5_KTNAME will be used.
3284 WARNING: The connection may transmit requests from multiple
3285 clients. Negotiate often assumes end-to-end authentication
3286 and a single-client. Which is not strictly true here.
3288 login=NEGOTIATE:principal_name
3289 If this is a personal/workgroup proxy and your parent
3290 requires a secure proxy authentication.
3291 The principal principal_name from the default keytab or
3292 defined by the environment variable KRB5_KTNAME will be
3295 WARNING: The connection may transmit requests from multiple
3296 clients. Negotiate often assumes end-to-end authentication
3297 and a single-client. Which is not strictly true here.
3299 connection-auth=on|off
3300 Tell Squid that this peer does or not support Microsoft
3301 connection oriented authentication, and any such
3302 challenges received from there should be ignored.
3303 Default is auto to automatically determine the status
3307 ==== SSL / HTTPS / TLS OPTIONS ====
3309 ssl Encrypt connections to this peer with SSL/TLS.
3311 sslcert=/path/to/ssl/certificate
3312 A client SSL certificate to use when connecting to
3315 sslkey=/path/to/ssl/key
3316 The private SSL key corresponding to sslcert above.
3317 If 'sslkey' is not specified 'sslcert' is assumed to
3318 reference a combined file containing both the
3319 certificate and the key.
3321 sslcipher=... The list of valid SSL ciphers to use when connecting
3325 The minimum TLS protocol version to permit. To control
3326 SSLv3 use the ssloptions= parameter.
3327 Supported Values: 1.0 (default), 1.1, 1.2
3329 ssloptions=... Specify various SSL implementation options:
3331 NO_SSLv3 Disallow the use of SSLv3
3333 NO_TLSv1 Disallow the use of TLSv1.0
3335 NO_TLSv1_1 Disallow the use of TLSv1.1
3337 NO_TLSv1_2 Disallow the use of TLSv1.2
3340 Always create a new key when using
3341 temporary/ephemeral DH key exchanges
3344 Disable use of RFC5077 session tickets.
3345 Some servers may have problems
3346 understanding the TLS extension due
3347 to ambiguous specification in RFC4507.
3349 ALL Enable various bug workarounds
3350 suggested as "harmless" by OpenSSL
3351 Be warned that this reduces SSL/TLS
3352 strength to some attacks.
3354 See the OpenSSL SSL_CTX_set_options documentation for a
3357 sslcafile=... A file containing additional CA certificates to use
3358 when verifying the peer certificate.
3360 sslcapath=... A directory containing additional CA certificates to
3361 use when verifying the peer certificate.
3363 sslcrlfile=... A certificate revocation list file to use when
3364 verifying the peer certificate.
3366 sslflags=... Specify various flags modifying the SSL implementation:
3369 Accept certificates even if they fail to
3373 Don't use the default CA list built in
3377 Don't verify the peer certificate
3378 matches the server name
3380 ssldomain= The peer name as advertised in it's certificate.
3381 Used for verifying the correctness of the received peer
3382 certificate. If not specified the peer hostname will be
3386 Enable the "Front-End-Https: On" header needed when
3387 using Squid as a SSL frontend in front of Microsoft OWA.
3388 See MS KB document Q307347 for details on this header.
3389 If set to auto the header will only be added if the
3390 request is forwarded as a https:// URL.
3393 ==== GENERAL OPTIONS ====
3396 A peer-specific connect timeout.
3397 Also see the peer_connect_timeout directive.
3399 connect-fail-limit=N
3400 How many times connecting to a peer must fail before
3401 it is marked as down. Standby connection failures
3402 count towards this limit. Default is 10.
3404 allow-miss Disable Squid's use of only-if-cached when forwarding
3405 requests to siblings. This is primarily useful when
3406 icp_hit_stale is used by the sibling. To extensive use
3407 of this option may result in forwarding loops, and you
3408 should avoid having two-way peerings with this option.
3409 For example to deny peer usage on requests from peer
3410 by denying cache_peer_access if the source is a peer.
3412 max-conn=N Limit the number of concurrent connections the Squid
3413 may open to this peer, including already opened idle
3414 and standby connections. There is no peer-specific
3415 connection limit by default.
3417 A peer exceeding the limit is not used for new
3418 requests unless a standby connection is available.
3420 max-conn currently works poorly with idle persistent
3421 connections: When a peer reaches its max-conn limit,
3422 and there are idle persistent connections to the peer,
3423 the peer may not be selected because the limiting code
3424 does not know whether Squid can reuse those idle
3427 standby=N Maintain a pool of N "hot standby" connections to an
3428 UP peer, available for requests when no idle
3429 persistent connection is available (or safe) to use.
3430 By default and with zero N, no such pool is maintained.
3431 N must not exceed the max-conn limit (if any).
3433 At start or after reconfiguration, Squid opens new TCP
3434 standby connections until there are N connections
3435 available and then replenishes the standby pool as
3436 opened connections are used up for requests. A used
3437 connection never goes back to the standby pool, but
3438 may go to the regular idle persistent connection pool
3439 shared by all peers and origin servers.
3441 Squid never opens multiple new standby connections
3442 concurrently. This one-at-a-time approach minimizes
3443 flooding-like effect on peers. Furthermore, just a few
3444 standby connections should be sufficient in most cases
3445 to supply most new requests with a ready-to-use
3448 Standby connections obey server_idle_pconn_timeout.
3449 For the feature to work as intended, the peer must be
3450 configured to accept and keep them open longer than
3451 the idle timeout at the connecting Squid, to minimize
3452 race conditions typical to idle used persistent
3453 connections. Default request_timeout and
3454 server_idle_pconn_timeout values ensure such a
3457 name=xxx Unique name for the peer.
3458 Required if you have multiple peers on the same host
3459 but different ports.
3460 This name can be used in cache_peer_access and similar
3461 directives to dentify the peer.
3462 Can be used by outgoing access controls through the
3465 no-tproxy Do not use the client-spoof TPROXY support when forwarding
3466 requests to this peer. Use normal address selection instead.
3467 This overrides the spoof_client_ip ACL.
3469 proxy-only objects fetched from the peer will not be stored locally.
3473 NAME: cache_peer_access
3478 Use to limit the requests for which a neighbor proxy will be
3479 queried. Peers with no restrictions are queried for all requests.
3482 cache_peer_access cache-host allow|deny [!]aclname ...
3484 The syntax is identical to 'http_access' and the other lists of
3485 ACL elements. See the comments for 'http_access', or the
3486 Squid FAQ (http://wiki.squid-cache.org/SquidFaq/SquidAcl).
3489 NAME: neighbor_type_domain
3490 TYPE: hostdomaintype
3492 DEFAULT_DOC: The peer type from cache_peer directive is used for all requests to that peer.
3495 Modify the cache_peer neighbor type when passing requests
3496 about specific domains to the peer.
3499 neighbor_type_domain neighbor parent|sibling domain domain ...
3502 cache_peer foo.example.com parent 3128 3130
3503 neighbor_type_domain foo.example.com sibling .au .de
3505 The above configuration treats all requests to foo.example.com as a
3506 parent proxy unless the request is for a .au or .de ccTLD domain name.
3509 NAME: dead_peer_timeout
3513 LOC: Config.Timeout.deadPeer
3515 This controls how long Squid waits to declare a peer cache
3516 as "dead." If there are no ICP replies received in this
3517 amount of time, Squid will declare the peer dead and not
3518 expect to receive any further ICP replies. However, it
3519 continues to send ICP queries, and will mark the peer as
3520 alive upon receipt of the first subsequent ICP reply.
3522 This timeout also affects when Squid expects to receive ICP
3523 replies from peers. If more than 'dead_peer' seconds have
3524 passed since the last ICP reply was received, Squid will not
3525 expect to receive an ICP reply on the next query. Thus, if
3526 your time between requests is greater than this timeout, you
3527 will see a lot of requests sent DIRECT to origin servers
3528 instead of to your parents.
3531 NAME: forward_max_tries
3534 LOC: Config.forward_max_tries
3536 Controls how many different forward paths Squid will try
3537 before giving up. See also forward_timeout.
3539 NOTE: connect_retries (default: none) can make each of these
3540 possible forwarding paths be tried multiple times.
3544 MEMORY CACHE OPTIONS
3545 -----------------------------------------------------------------------------
3552 LOC: Config.memMaxSize
3554 NOTE: THIS PARAMETER DOES NOT SPECIFY THE MAXIMUM PROCESS SIZE.
3555 IT ONLY PLACES A LIMIT ON HOW MUCH ADDITIONAL MEMORY SQUID WILL
3556 USE AS A MEMORY CACHE OF OBJECTS. SQUID USES MEMORY FOR OTHER
3557 THINGS AS WELL. SEE THE SQUID FAQ SECTION 8 FOR DETAILS.
3559 'cache_mem' specifies the ideal amount of memory to be used
3561 * In-Transit objects
3563 * Negative-Cached objects
3565 Data for these objects are stored in 4 KB blocks. This
3566 parameter specifies the ideal upper limit on the total size of
3567 4 KB blocks allocated. In-Transit objects take the highest
3570 In-transit objects have priority over the others. When
3571 additional space is needed for incoming data, negative-cached
3572 and hot objects will be released. In other words, the
3573 negative-cached and hot objects will fill up any unused space
3574 not needed for in-transit objects.
3576 If circumstances require, this limit will be exceeded.
3577 Specifically, if your incoming request rate requires more than
3578 'cache_mem' of memory to hold in-transit objects, Squid will
3579 exceed this limit to satisfy the new requests. When the load
3580 decreases, blocks will be freed until the high-water mark is
3581 reached. Thereafter, blocks will be used to store hot
3584 If shared memory caching is enabled, Squid does not use the shared
3585 cache space for in-transit objects, but they still consume as much
3586 local memory as they need. For more details about the shared memory
3587 cache, see memory_cache_shared.
3590 NAME: maximum_object_size_in_memory
3594 LOC: Config.Store.maxInMemObjSize
3596 Objects greater than this size will not be attempted to kept in
3597 the memory cache. This should be set high enough to keep objects
3598 accessed frequently in memory to improve performance whilst low
3599 enough to keep larger objects from hoarding cache_mem.
3602 NAME: memory_cache_shared
3605 LOC: Config.memShared
3607 DEFAULT_DOC: "on" where supported if doing memory caching with multiple SMP workers.
3609 Controls whether the memory cache is shared among SMP workers.
3611 The shared memory cache is meant to occupy cache_mem bytes and replace
3612 the non-shared memory cache, although some entities may still be
3613 cached locally by workers for now (e.g., internal and in-transit
3614 objects may be served from a local memory cache even if shared memory
3615 caching is enabled).
3617 By default, the memory cache is shared if and only if all of the
3618 following conditions are satisfied: Squid runs in SMP mode with
3619 multiple workers, cache_mem is positive, and Squid environment
3620 supports required IPC primitives (e.g., POSIX shared memory segments
3621 and GCC-style atomic operations).
3623 To avoid blocking locks, shared memory uses opportunistic algorithms
3624 that do not guarantee that every cachable entity that could have been
3625 shared among SMP workers will actually be shared.
3627 Currently, entities exceeding 32KB in size cannot be shared.
3630 NAME: memory_cache_mode
3634 DEFAULT_DOC: Keep the most recently fetched objects in memory
3636 Controls which objects to keep in the memory cache (cache_mem)
3638 always Keep most recently fetched objects in memory (default)
3640 disk Only disk cache hits are kept in memory, which means
3641 an object must first be cached on disk and then hit
3642 a second time before cached in memory.
3644 network Only objects fetched from network is kept in memory
3647 NAME: memory_replacement_policy
3649 LOC: Config.memPolicy
3652 The memory replacement policy parameter determines which
3653 objects are purged from memory when memory space is needed.
3655 See cache_replacement_policy for details on algorithms.
3660 -----------------------------------------------------------------------------
3663 NAME: cache_replacement_policy
3665 LOC: Config.replPolicy
3668 The cache replacement policy parameter determines which
3669 objects are evicted (replaced) when disk space is needed.
3671 lru : Squid's original list based LRU policy
3672 heap GDSF : Greedy-Dual Size Frequency
3673 heap LFUDA: Least Frequently Used with Dynamic Aging
3674 heap LRU : LRU policy implemented using a heap
3676 Applies to any cache_dir lines listed below this directive.
3678 The LRU policies keeps recently referenced objects.
3680 The heap GDSF policy optimizes object hit rate by keeping smaller
3681 popular objects in cache so it has a better chance of getting a
3682 hit. It achieves a lower byte hit rate than LFUDA though since
3683 it evicts larger (possibly popular) objects.
3685 The heap LFUDA policy keeps popular objects in cache regardless of
3686 their size and thus optimizes byte hit rate at the expense of
3687 hit rate since one large, popular object will prevent many
3688 smaller, slightly less popular objects from being cached.
3690 Both policies utilize a dynamic aging mechanism that prevents
3691 cache pollution that can otherwise occur with frequency-based
3692 replacement policies.
3694 NOTE: if using the LFUDA replacement policy you should increase
3695 the value of maximum_object_size above its default of 4 MB to
3696 to maximize the potential byte hit rate improvement of LFUDA.
3698 For more information about the GDSF and LFUDA cache replacement
3699 policies see http://www.hpl.hp.com/techreports/1999/HPL-1999-69.html
3700 and http://fog.hpl.external.hp.com/techreports/98/HPL-98-173.html.
3703 NAME: minimum_object_size
3707 DEFAULT_DOC: no limit
3708 LOC: Config.Store.minObjectSize
3710 Objects smaller than this size will NOT be saved on disk. The
3711 value is specified in bytes, and the default is 0 KB, which
3712 means all responses can be stored.
3715 NAME: maximum_object_size
3719 LOC: Config.Store.maxObjectSize
3721 Set the default value for max-size parameter on any cache_dir.
3722 The value is specified in bytes, and the default is 4 MB.
3724 If you wish to get a high BYTES hit ratio, you should probably
3725 increase this (one 32 MB object hit counts for 3200 10KB
3728 If you wish to increase hit ratio more than you want to
3729 save bandwidth you should leave this low.
3731 NOTE: if using the LFUDA replacement policy you should increase
3732 this value to maximize the byte hit rate improvement of LFUDA!
3733 See cache_replacement_policy for a discussion of this policy.
3739 DEFAULT_DOC: No disk cache. Store cache ojects only in memory.
3740 LOC: Config.cacheSwap
3743 cache_dir Type Directory-Name Fs-specific-data [options]
3745 You can specify multiple cache_dir lines to spread the
3746 cache among different disk partitions.
3748 Type specifies the kind of storage system to use. Only "ufs"
3749 is built by default. To enable any of the other storage systems
3750 see the --enable-storeio configure option.
3752 'Directory' is a top-level directory where cache swap
3753 files will be stored. If you want to use an entire disk
3754 for caching, this can be the mount-point directory.
3755 The directory must exist and be writable by the Squid
3756 process. Squid will NOT create this directory for you.
3758 In SMP configurations, cache_dir must not precede the workers option
3759 and should use configuration macros or conditionals to give each
3760 worker interested in disk caching a dedicated cache directory.
3763 ==== The ufs store type ====
3765 "ufs" is the old well-known Squid storage format that has always
3769 cache_dir ufs Directory-Name Mbytes L1 L2 [options]
3771 'Mbytes' is the amount of disk space (MB) to use under this
3772 directory. The default is 100 MB. Change this to suit your
3773 configuration. Do NOT put the size of your disk drive here.
3774 Instead, if you want Squid to use the entire disk drive,
3775 subtract 20% and use that value.
3777 'L1' is the number of first-level subdirectories which
3778 will be created under the 'Directory'. The default is 16.
3780 'L2' is the number of second-level subdirectories which
3781 will be created under each first-level directory. The default
3785 ==== The aufs store type ====
3787 "aufs" uses the same storage format as "ufs", utilizing
3788 POSIX-threads to avoid blocking the main Squid process on
3789 disk-I/O. This was formerly known in Squid as async-io.
3792 cache_dir aufs Directory-Name Mbytes L1 L2 [options]
3794 see argument descriptions under ufs above
3797 ==== The diskd store type ====
3799 "diskd" uses the same storage format as "ufs", utilizing a
3800 separate process to avoid blocking the main Squid process on
3804 cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n]
3806 see argument descriptions under ufs above
3808 Q1 specifies the number of unacknowledged I/O requests when Squid
3809 stops opening new files. If this many messages are in the queues,
3810 Squid won't open new files. Default is 64
3812 Q2 specifies the number of unacknowledged messages when Squid
3813 starts blocking. If this many messages are in the queues,
3814 Squid blocks until it receives some replies. Default is 72
3816 When Q1 < Q2 (the default), the cache directory is optimized
3817 for lower response time at the expense of a decrease in hit
3818 ratio. If Q1 > Q2, the cache directory is optimized for
3819 higher hit ratio at the expense of an increase in response
3823 ==== The rock store type ====
3826 cache_dir rock Directory-Name Mbytes [options]
3828 The Rock Store type is a database-style storage. All cached
3829 entries are stored in a "database" file, using fixed-size slots.
3830 A single entry occupies one or more slots.
3832 If possible, Squid using Rock Store creates a dedicated kid
3833 process called "disker" to avoid blocking Squid worker(s) on disk
3834 I/O. One disker kid is created for each rock cache_dir. Diskers
3835 are created only when Squid, running in daemon mode, has support
3836 for the IpcIo disk I/O module.
3838 swap-timeout=msec: Squid will not start writing a miss to or
3839 reading a hit from disk if it estimates that the swap operation
3840 will take more than the specified number of milliseconds. By
3841 default and when set to zero, disables the disk I/O time limit
3842 enforcement. Ignored when using blocking I/O module because
3843 blocking synchronous I/O does not allow Squid to estimate the
3844 expected swap wait time.
3846 max-swap-rate=swaps/sec: Artificially limits disk access using
3847 the specified I/O rate limit. Swap out requests that
3848 would cause the average I/O rate to exceed the limit are
3849 delayed. Individual swap in requests (i.e., hits or reads) are
3850 not delayed, but they do contribute to measured swap rate and
3851 since they are placed in the same FIFO queue as swap out
3852 requests, they may wait longer if max-swap-rate is smaller.
3853 This is necessary on file systems that buffer "too
3854 many" writes and then start blocking Squid and other processes
3855 while committing those writes to disk. Usually used together
3856 with swap-timeout to avoid excessive delays and queue overflows
3857 when disk demand exceeds available disk "bandwidth". By default
3858 and when set to zero, disables the disk I/O rate limit
3859 enforcement. Currently supported by IpcIo module only.
3861 slot-size=bytes: The size of a database "record" used for
3862 storing cached responses. A cached response occupies at least
3863 one slot and all database I/O is done using individual slots so
3864 increasing this parameter leads to more disk space waste while
3865 decreasing it leads to more disk I/O overheads. Should be a
3866 multiple of your operating system I/O page size. Defaults to
3867 16KBytes. A housekeeping header is stored with each slot and
3868 smaller slot-sizes will be rejected. The header is smaller than
3872 ==== COMMON OPTIONS ====
3874 no-store no new objects should be stored to this cache_dir.
3876 min-size=n the minimum object size in bytes this cache_dir
3877 will accept. It's used to restrict a cache_dir
3878 to only store large objects (e.g. AUFS) while
3879 other stores are optimized for smaller objects
3883 max-size=n the maximum object size in bytes this cache_dir
3885 The value in maximum_object_size directive sets
3886 the default unless more specific details are
3887 available (ie a small store capacity).
3889 Note: To make optimal use of the max-size limits you should order
3890 the cache_dir lines with the smallest max-size value first.
3894 # Uncomment and adjust the following to add a disk cache directory.
3895 #cache_dir ufs @DEFAULT_SWAP_DIR@ 100 16 256
3899 NAME: store_dir_select_algorithm
3901 LOC: Config.store_dir_select_algorithm
3904 How Squid selects which cache_dir to use when the response
3905 object will fit into more than one.
3907 Regardless of which algorithm is used the cache_dir min-size
3908 and max-size parameters are obeyed. As such they can affect
3909 the selection algorithm by limiting the set of considered
3916 This algorithm is suited to caches with similar cache_dir
3917 sizes and disk speeds.
3919 The disk with the least I/O pending is selected.
3920 When there are multiple disks with the same I/O load ranking
3921 the cache_dir with most available capacity is selected.
3923 When a mix of cache_dir sizes are configured the faster disks
3924 have a naturally lower I/O loading and larger disks have more
3925 capacity. So space used to store objects and data throughput
3926 may be very unbalanced towards larger disks.
3931 This algorithm is suited to caches with unequal cache_dir
3934 Each cache_dir is selected in a rotation. The next suitable
3937 Available cache_dir capacity is only considered in relation
3938 to whether the object will fit and meets the min-size and
3939 max-size parameters.
3941 Disk I/O loading is only considered to prevent overload on slow
3942 disks. This algorithm does not spread objects by size, so any
3943 I/O loading per-disk may appear very unbalanced and volatile.
3945 If several cache_dirs use similar min-size, max-size, or other
3946 limits to to reject certain responses, then do not group such
3947 cache_dir lines together, to avoid round-robin selection bias
3948 towards the first cache_dir after the group. Instead, interleave
3949 cache_dir lines from different groups. For example:
3951 store_dir_select_algorithm round-robin
3952 cache_dir rock /hdd1 ... min-size=100000
3953 cache_dir rock /ssd1 ... max-size=99999
3954 cache_dir rock /hdd2 ... min-size=100000
3955 cache_dir rock /ssd2 ... max-size=99999
3956 cache_dir rock /hdd3 ... min-size=100000
3957 cache_dir rock /ssd3 ... max-size=99999
3960 NAME: max_open_disk_fds
3962 LOC: Config.max_open_disk_fds
3964 DEFAULT_DOC: no limit
3966 To avoid having disk as the I/O bottleneck Squid can optionally
3967 bypass the on-disk cache if more than this amount of disk file
3968 descriptors are open.
3970 A value of 0 indicates no limit.
3973 NAME: cache_swap_low
3974 COMMENT: (percent, 0-100)
3977 LOC: Config.Swap.lowWaterMark
3979 The low-water mark for AUFS/UFS/diskd cache object eviction by
3980 the cache_replacement_policy algorithm.
3982 Removal begins when the swap (disk) usage of a cache_dir is
3983 above this low-water mark and attempts to maintain utilization
3984 near the low-water mark.
3986 As swap utilization increases towards the high-water mark set
3987 by cache_swap_high object eviction becomes more agressive.
3989 The value difference in percentages between low- and high-water
3990 marks represent an eviction rate of 300 objects per second and
3991 the rate continues to scale in agressiveness by multiples of
3992 this above the high-water mark.
3994 Defaults are 90% and 95%. If you have a large cache, 5% could be
3995 hundreds of MB. If this is the case you may wish to set these
3996 numbers closer together.
3998 See also cache_swap_high and cache_replacement_policy
4001 NAME: cache_swap_high
4002 COMMENT: (percent, 0-100)
4005 LOC: Config.Swap.highWaterMark
4007 The high-water mark for AUFS/UFS/diskd cache object eviction by
4008 the cache_replacement_policy algorithm.
4010 Removal begins when the swap (disk) usage of a cache_dir is
4011 above the low-water mark set by cache_swap_low and attempts to
4012 maintain utilization near the low-water mark.
4014 As swap utilization increases towards this high-water mark object
4015 eviction becomes more agressive.
4017 The value difference in percentages between low- and high-water
4018 marks represent an eviction rate of 300 objects per second and
4019 the rate continues to scale in agressiveness by multiples of
4020 this above the high-water mark.
4022 Defaults are 90% and 95%. If you have a large cache, 5% could be
4023 hundreds of MB. If this is the case you may wish to set these
4024 numbers closer together.
4026 See also cache_swap_low and cache_replacement_policy
4031 -----------------------------------------------------------------------------
4038 DEFAULT_DOC: The format definitions squid, common, combined, referrer, useragent are built in.
4042 logformat <name> <format specification>
4044 Defines an access log format.
4046 The <format specification> is a string with embedded % format codes
4048 % format codes all follow the same basic structure where all but
4049 the formatcode is optional. Output strings are automatically escaped
4050 as required according to their context and the output format
4051 modifiers are usually not needed, but can be specified if an explicit
4052 output format is desired.
4054 % ["|[|'|#|/] [-] [[0]width] [{arg}] formatcode [{arg}]
4056 " output in quoted string format
4057 [ output in squid text log format as used by log_mime_hdrs
4058 # output in URL quoted format
4059 / output in shell \-escaped format
4064 width minimum and/or maximum field width:
4065 [width_min][.width_max]
4066 When minimum starts with 0, the field is zero-padded.
4067 String values exceeding maximum width are truncated.
4069 {arg} argument such as header name etc. This field may be
4070 placed before or after the token, but not both at once.
4074 % a literal % character
4075 sn Unique sequence number per log line entry
4076 err_code The ID of an error response served by Squid or
4077 a similar internal error identifier.
4078 err_detail Additional err_code-dependent error information.
4079 note The annotation specified by the argument. Also
4080 logs the adaptation meta headers set by the
4081 adaptation_meta configuration parameter.
4082 If no argument given all annotations logged.
4083 The argument may include a separator to use with
4086 By default, multiple note values are separated with ","
4087 and multiple notes are separated with "\r\n".
4088 When logging named notes with %{name}note, the
4089 explicitly configured separator is used between note
4090 values. When logging all notes with %note, the
4091 explicitly configured separator is used between
4092 individual notes. There is currently no way to
4093 specify both value and notes separators when logging
4094 all notes with %note.
4096 Connection related format codes:
4098 >a Client source IP address
4100 >p Client source port
4101 >eui Client source EUI (MAC address, EUI-48 or EUI-64 identifier)
4102 >la Local IP address the client connected to
4103 >lp Local port number the client connected to
4104 >qos Client connection TOS/DSCP value set by Squid
4105 >nfmark Client connection netfilter mark set by Squid
4107 la Local listening IP address the client connection was connected to.
4108 lp Local listening port number the client connection was connected to.
4110 <a Server IP address of the last server or peer connection
4111 <A Server FQDN or peer name
4112 <p Server port number of the last server or peer connection
4113 <la Local IP address of the last server or peer connection
4114 <lp Local port number of the last server or peer connection
4115 <qos Server connection TOS/DSCP value set by Squid
4116 <nfmark Server connection netfilter mark set by Squid
4118 Time related format codes:
4120 ts Seconds since epoch
4121 tu subsecond time (milliseconds)
4122 tl Local time. Optional strftime format argument
4123 default %d/%b/%Y:%H:%M:%S %z
4124 tg GMT time. Optional strftime format argument
4125 default %d/%b/%Y:%H:%M:%S %z
4126 tr Response time (milliseconds)
4127 dt Total time spent making DNS lookups (milliseconds)
4128 tS Approximate master transaction start time in
4129 <full seconds since epoch>.<fractional seconds> format.
4130 Currently, Squid considers the master transaction
4131 started when a complete HTTP request header initiating
4132 the transaction is received from the client. This is
4133 the same value that Squid uses to calculate transaction
4134 response time when logging %tr to access.log. Currently,
4135 Squid uses millisecond resolution for %tS values,
4136 similar to the default access.log "current time" field
4139 Access Control related format codes:
4141 et Tag returned by external acl
4142 ea Log string returned by external acl
4143 un User name (any available)
4144 ul User name from authentication
4145 ue User name from external acl helper
4146 ui User name from ident
4147 un A user name. Expands to the first available name
4148 from the following list of information sources:
4149 - authenticated user name, like %ul
4150 - user name supplied by an external ACL, like %ue
4151 - SSL client name, like %us
4152 - ident user name, like %ui
4153 credentials Client credentials. The exact meaning depends on
4154 the authentication scheme: For Basic authentication,
4155 it is the password; for Digest, the realm sent by the
4156 client; for NTLM and Negotiate, the client challenge
4157 or client credentials prefixed with "YR " or "KK ".
4159 HTTP related format codes:
4163 [http::]rm Request method (GET/POST etc)
4164 [http::]>rm Request method from client
4165 [http::]<rm Request method sent to server or peer
4166 [http::]ru Request URL from client (historic, filtered for logging)
4167 [http::]>ru Request URL from client
4168 [http::]<ru Request URL sent to server or peer
4169 [http::]>rs Request URL scheme from client
4170 [http::]<rs Request URL scheme sent to server or peer
4171 [http::]>rd Request URL domain from client
4172 [http::]<rd Request URL domain sent to server or peer
4173 [http::]>rP Request URL port from client
4174 [http::]<rP Request URL port sent to server or peer
4175 [http::]rp Request URL path excluding hostname
4176 [http::]>rp Request URL path excluding hostname from client
4177 [http::]<rp Request URL path excluding hostname sent to server or peer
4178 [http::]rv Request protocol version
4179 [http::]>rv Request protocol version from client
4180 [http::]<rv Request protocol version sent to server or peer
4182 [http::]>h Original received request header.
4183 Usually differs from the request header sent by
4184 Squid, although most fields are often preserved.
4185 Accepts optional header field name/value filter
4186 argument using name[:[separator]element] format.
4187 [http::]>ha Received request header after adaptation and
4188 redirection (pre-cache REQMOD vectoring point).
4189 Usually differs from the request header sent by
4190 Squid, although most fields are often preserved.
4191 Optional header name argument as for >h
4196 [http::]<Hs HTTP status code received from the next hop
4197 [http::]>Hs HTTP status code sent to the client
4199 [http::]<h Reply header. Optional header name argument
4202 [http::]mt MIME content type
4207 [http::]st Total size of request + reply traffic with client
4208 [http::]>st Total size of request received from client.
4209 Excluding chunked encoding bytes.
4210 [http::]<st Total size of reply sent to client (after adaptation)
4212 [http::]>sh Size of request headers received from client
4213 [http::]<sh Size of reply headers sent to client (after adaptation)
4215 [http::]<sH Reply high offset sent
4216 [http::]<sS Upstream object size
4218 [http::]<bs Number of HTTP-equivalent message body bytes
4219 received from the next hop, excluding chunked
4220 transfer encoding and control messages.
4221 Generated FTP/Gopher listings are treated as
4227 [http::]<pt Peer response time in milliseconds. The timer starts
4228 when the last request byte is sent to the next hop
4229 and stops when the last response byte is received.
4230 [http::]<tt Total time in milliseconds. The timer
4231 starts with the first connect request (or write I/O)
4232 sent to the first selected peer. The timer stops
4233 with the last I/O with the last peer.
4235 Squid handling related format codes:
4237 Ss Squid request status (TCP_MISS etc)
4238 Sh Squid hierarchy status (DEFAULT_PARENT etc)
4240 SSL-related format codes:
4242 ssl::bump_mode SslBump decision for the transaction:
4244 For CONNECT requests that initiated bumping of
4245 a connection and for any request received on
4246 an already bumped connection, Squid logs the
4247 corresponding SslBump mode ("server-first" or
4248 "client-first"). See the ssl_bump option for
4249 more information about these modes.
4251 A "none" token is logged for requests that
4252 triggered "ssl_bump" ACL evaluation matching
4253 either a "none" rule or no rules at all.
4255 In all other cases, a single dash ("-") is
4258 ssl::>sni SSL client SNI sent to Squid. Available only
4259 after the peek, stare, or splice SSL bumping
4262 If ICAP is enabled, the following code becomes available (as
4263 well as ICAP log codes documented with the icap_log option):
4265 icap::tt Total ICAP processing time for the HTTP
4266 transaction. The timer ticks when ICAP
4267 ACLs are checked and when ICAP
4268 transaction is in progress.
4270 If adaptation is enabled the following three codes become available:
4272 adapt::<last_h The header of the last ICAP response or
4273 meta-information from the last eCAP
4274 transaction related to the HTTP transaction.
4275 Like <h, accepts an optional header name
4278 adapt::sum_trs Summed adaptation transaction response
4279 times recorded as a comma-separated list in
4280 the order of transaction start time. Each time
4281 value is recorded as an integer number,
4282 representing response time of one or more
4283 adaptation (ICAP or eCAP) transaction in
4284 milliseconds. When a failed transaction is
4285 being retried or repeated, its time is not
4286 logged individually but added to the
4287 replacement (next) transaction. See also:
4290 adapt::all_trs All adaptation transaction response times.
4291 Same as adaptation_strs but response times of
4292 individual transactions are never added
4293 together. Instead, all transaction response
4294 times are recorded individually.
4296 You can prefix adapt::*_trs format codes with adaptation
4297 service name in curly braces to record response time(s) specific
4298 to that service. For example: %{my_service}adapt::sum_trs
4300 If SSL is enabled, the following formating codes become available:
4302 %ssl::>cert_subject The Subject field of the received client
4303 SSL certificate or a dash ('-') if Squid has
4304 received an invalid/malformed certificate or
4305 no certificate at all. Consider encoding the
4306 logged value because Subject often has spaces.
4308 %ssl::>cert_issuer The Issuer field of the received client
4309 SSL certificate or a dash ('-') if Squid has
4310 received an invalid/malformed certificate or
4311 no certificate at all. Consider encoding the
4312 logged value because Issuer often has spaces.
4314 The default formats available (which do not need re-defining) are:
4316 logformat squid %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %[un %Sh/%<a %mt
4317 logformat common %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st %Ss:%Sh
4318 logformat combined %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
4319 logformat referrer %ts.%03tu %>a %{Referer}>h %ru
4320 logformat useragent %>a [%tl] "%{User-Agent}>h"
4322 NOTE: When the log_mime_hdrs directive is set to ON.
4323 The squid, common and combined formats have a safely encoded copy
4324 of the mime headers appended to each line within a pair of brackets.
4326 NOTE: The common and combined formats are not quite true to the Apache definition.
4327 The logs from Squid contain an extra status and hierarchy code appended.
4331 NAME: access_log cache_access_log
4333 LOC: Config.Log.accesslogs
4334 DEFAULT_IF_NONE: daemon:@DEFAULT_ACCESS_LOG@ squid
4336 Configures whether and how Squid logs HTTP and ICP transactions.
4337 If access logging is enabled, a single line is logged for every
4338 matching HTTP or ICP request. The recommended directive formats are:
4340 access_log <module>:<place> [option ...] [acl acl ...]
4341 access_log none [acl acl ...]
4343 The following directive format is accepted but may be deprecated:
4344 access_log <module>:<place> [<logformat name> [acl acl ...]]
4346 In most cases, the first ACL name must not contain the '=' character
4347 and should not be equal to an existing logformat name. You can always
4348 start with an 'all' ACL to work around those restrictions.
4350 Will log to the specified module:place using the specified format (which
4351 must be defined in a logformat directive) those entries which match
4352 ALL the acl's specified (which must be defined in acl clauses).
4353 If no acl is specified, all requests will be logged to this destination.
4355 ===== Available options for the recommended directive format =====
4357 logformat=name Names log line format (either built-in or
4358 defined by a logformat directive). Defaults
4361 buffer-size=64KB Defines approximate buffering limit for log
4362 records (see buffered_logs). Squid should not
4363 keep more than the specified size and, hence,
4364 should flush records before the buffer becomes
4365 full to avoid overflows under normal
4366 conditions (the exact flushing algorithm is
4367 module-dependent though). The on-error option
4368 controls overflow handling.
4370 on-error=die|drop Defines action on unrecoverable errors. The
4371 'drop' action ignores (i.e., does not log)
4372 affected log records. The default 'die' action
4373 kills the affected worker. The drop action
4374 support has not been tested for modules other
4377 rotate=N Specifies the number of log file rotations to
4378 make when you run 'squid -k rotate'. The default
4379 is to obey the logfile_rotate directive. Setting
4380 rotate=0 will disable the file name rotation,
4381 but the log files are still closed and re-opened.
4382 This will enable you to rename the logfiles
4383 yourself just before sending the rotate signal.
4384 Only supported by the stdio module.
4386 ===== Modules Currently available =====
4388 none Do not log any requests matching these ACL.
4389 Do not specify Place or logformat name.
4391 stdio Write each log line to disk immediately at the completion of
4393 Place: the filename and path to be written.
4395 daemon Very similar to stdio. But instead of writing to disk the log
4396 line is passed to a daemon helper for asychronous handling instead.
4397 Place: varies depending on the daemon.
4399 log_file_daemon Place: the file name and path to be written.
4401 syslog To log each request via syslog facility.
4402 Place: The syslog facility and priority level for these entries.
4403 Place Format: facility.priority
4405 where facility could be any of:
4406 authpriv, daemon, local0 ... local7 or user.
4408 And priority could be any of:
4409 err, warning, notice, info, debug.
4411 udp To send each log line as text data to a UDP receiver.
4412 Place: The destination host name or IP and port.
4413 Place Format: //host:port
4415 tcp To send each log line as text data to a TCP receiver.
4416 Lines may be accumulated before sending (see buffered_logs).
4417 Place: The destination host name or IP and port.
4418 Place Format: //host:port
4421 access_log daemon:@DEFAULT_ACCESS_LOG@ squid
4427 LOC: Config.Log.icaplogs
4430 ICAP log files record ICAP transaction summaries, one line per
4433 The icap_log option format is:
4434 icap_log <filepath> [<logformat name> [acl acl ...]]
4435 icap_log none [acl acl ...]]
4437 Please see access_log option documentation for details. The two
4438 kinds of logs share the overall configuration approach and many
4441 ICAP processing of a single HTTP message or transaction may
4442 require multiple ICAP transactions. In such cases, multiple
4443 ICAP transaction log lines will correspond to a single access
4446 ICAP log uses logformat codes that make sense for an ICAP
4447 transaction. Header-related codes are applied to the HTTP header
4448 embedded in an ICAP server response, with the following caveats:
4449 For REQMOD, there is no HTTP response header unless the ICAP
4450 server performed request satisfaction. For RESPMOD, the HTTP
4451 request header is the header sent to the ICAP server. For
4452 OPTIONS, there are no HTTP headers.
4454 The following format codes are also available for ICAP logs:
4456 icap::<A ICAP server IP address. Similar to <A.
4458 icap::<service_name ICAP service name from the icap_service
4459 option in Squid configuration file.
4461 icap::ru ICAP Request-URI. Similar to ru.
4463 icap::rm ICAP request method (REQMOD, RESPMOD, or
4464 OPTIONS). Similar to existing rm.
4466 icap::>st Bytes sent to the ICAP server (TCP payload
4467 only; i.e., what Squid writes to the socket).
4469 icap::<st Bytes received from the ICAP server (TCP
4470 payload only; i.e., what Squid reads from
4473 icap::<bs Number of message body bytes received from the
4474 ICAP server. ICAP message body, if any, usually
4475 includes encapsulated HTTP message headers and
4476 possibly encapsulated HTTP message body. The
4477 HTTP body part is dechunked before its size is
4480 icap::tr Transaction response time (in
4481 milliseconds). The timer starts when
4482 the ICAP transaction is created and
4483 stops when the transaction is completed.
4486 icap::tio Transaction I/O time (in milliseconds). The
4487 timer starts when the first ICAP request
4488 byte is scheduled for sending. The timers
4489 stops when the last byte of the ICAP response
4492 icap::to Transaction outcome: ICAP_ERR* for all
4493 transaction errors, ICAP_OPT for OPTION
4494 transactions, ICAP_ECHO for 204
4495 responses, ICAP_MOD for message
4496 modification, and ICAP_SAT for request
4497 satisfaction. Similar to Ss.
4499 icap::Hs ICAP response status code. Similar to Hs.
4501 icap::>h ICAP request header(s). Similar to >h.
4503 icap::<h ICAP response header(s). Similar to <h.
4505 The default ICAP log format, which can be used without an explicit
4506 definition, is called icap_squid:
4508 logformat icap_squid %ts.%03tu %6icap::tr %>a %icap::to/%03icap::Hs %icap::<size %icap::rm %icap::ru% %un -/%icap::<A -
4510 See also: logformat, log_icap, and %adapt::<last_h
4513 NAME: logfile_daemon
4515 DEFAULT: @DEFAULT_LOGFILED@
4516 LOC: Log::TheConfig.logfile_daemon
4518 Specify the path to the logfile-writing daemon. This daemon is
4519 used to write the access and store logs, if configured.
4521 Squid sends a number of commands to the log daemon:
4522 L<data>\n - logfile data
4527 r<n>\n - set rotate count to <n>
4528 b<n>\n - 1 = buffer output, 0 = don't buffer output
4530 No responses is expected.
4533 NAME: stats_collection
4535 LOC: Config.accessList.stats_collection
4537 DEFAULT_DOC: Allow logging for all transactions.
4538 COMMENT: allow|deny acl acl...
4540 This options allows you to control which requests gets accounted
4541 in performance counters.
4543 This clause only supports fast acl types.
4544 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4547 NAME: cache_store_log
4550 LOC: Config.Log.store
4552 Logs the activities of the storage manager. Shows which
4553 objects are ejected from the cache, and which objects are
4554 saved and for how long.
4555 There are not really utilities to analyze this data, so you can safely
4556 disable it (the default).
4558 Store log uses modular logging outputs. See access_log for the list
4559 of modules supported.
4562 cache_store_log stdio:@DEFAULT_STORE_LOG@
4563 cache_store_log daemon:@DEFAULT_STORE_LOG@
4566 NAME: cache_swap_state cache_swap_log
4568 LOC: Config.Log.swap
4570 DEFAULT_DOC: Store the journal inside its cache_dir
4572 Location for the cache "swap.state" file. This index file holds
4573 the metadata of objects saved on disk. It is used to rebuild
4574 the cache during startup. Normally this file resides in each
4575 'cache_dir' directory, but you may specify an alternate
4576 pathname here. Note you must give a full filename, not just
4577 a directory. Since this is the index for the whole object
4578 list you CANNOT periodically rotate it!
4580 If %s can be used in the file name it will be replaced with a
4581 a representation of the cache_dir name where each / is replaced
4582 with '.'. This is needed to allow adding/removing cache_dir
4583 lines when cache_swap_log is being used.
4585 If have more than one 'cache_dir', and %s is not used in the name
4586 these swap logs will have names such as:
4592 The numbered extension (which is added automatically)
4593 corresponds to the order of the 'cache_dir' lines in this
4594 configuration file. If you change the order of the 'cache_dir'
4595 lines in this file, these index files will NOT correspond to
4596 the correct 'cache_dir' entry (unless you manually rename
4597 them). We recommend you do NOT use this option. It is
4598 better to keep these index files in each 'cache_dir' directory.
4601 NAME: logfile_rotate
4604 LOC: Config.Log.rotateNumber
4606 Specifies the default number of logfile rotations to make when you
4607 type 'squid -k rotate'. The default is 10, which will rotate
4608 with extensions 0 through 9. Setting logfile_rotate to 0 will
4609 disable the file name rotation, but the logfiles are still closed
4610 and re-opened. This will enable you to rename the logfiles
4611 yourself just before sending the rotate signal.
4613 Note, from Squid-3.1 this option is only a default for cache.log,
4614 that log can be rotated separately by using debug_options.
4616 Note, from Squid-3.6 this option is only a default for access.log
4617 recorded by stdio: module. Those logs can be rotated separately by
4618 using the rotate=N option on their access_log directive.
4620 Note, the 'squid -k rotate' command normally sends a USR1
4621 signal to the running squid process. In certain situations
4622 (e.g. on Linux with Async I/O), USR1 is used for other
4623 purposes, so -k rotate uses another signal. It is best to get
4624 in the habit of using 'squid -k rotate' instead of 'kill -USR1
4631 DEFAULT: @DEFAULT_MIME_TABLE@
4632 LOC: Config.mimeTablePathname
4634 Path to Squid's icon configuration file.
4636 You shouldn't need to change this, but the default file contains
4637 examples and formatting information if you do.
4643 LOC: Config.onoff.log_mime_hdrs
4646 The Cache can record both the request and the response MIME
4647 headers for each HTTP transaction. The headers are encoded
4648 safely and will appear as two bracketed fields at the end of
4649 the access log (for either the native or httpd-emulated log
4650 formats). To enable this logging set log_mime_hdrs to 'on'.
4655 DEFAULT: @DEFAULT_PID_FILE@
4656 LOC: Config.pidFilename
4658 A filename to write the process-id to. To disable, enter "none".
4661 NAME: client_netmask
4663 LOC: Config.Addrs.client_netmask
4665 DEFAULT_DOC: Log full client IP address
4667 A netmask for client addresses in logfiles and cachemgr output.
4668 Change this to protect the privacy of your cache clients.
4669 A netmask of 255.255.255.0 will log all IP's in that range with
4670 the last digit set to '0'.
4673 NAME: strip_query_terms
4675 LOC: Config.onoff.strip_query_terms
4678 By default, Squid strips query terms from requested URLs before
4679 logging. This protects your user's privacy and reduces log size.
4681 When investigating HIT/MISS or other caching behaviour you
4682 will need to disable this to see the full URL used by Squid.
4689 LOC: Config.onoff.buffered_logs
4691 Whether to write/send access_log records ASAP or accumulate them and
4692 then write/send them in larger chunks. Buffering may improve
4693 performance because it decreases the number of I/Os. However,
4694 buffering increases the delay before log records become available to
4695 the final recipient (e.g., a disk file or logging daemon) and,
4696 hence, increases the risk of log records loss.
4698 Note that even when buffered_logs are off, Squid may have to buffer
4699 records if it cannot write/send them immediately due to pending I/Os
4700 (e.g., the I/O writing the previous log record) or connectivity loss.
4702 Currently honored by 'daemon' and 'tcp' access_log modules only.
4705 NAME: netdb_filename
4707 DEFAULT: stdio:@DEFAULT_NETDB_FILE@
4708 LOC: Config.netdbFilename
4711 Where Squid stores it's netdb journal.
4712 When enabled this journal preserves netdb state between restarts.
4714 To disable, enter "none".
4718 OPTIONS FOR TROUBLESHOOTING
4719 -----------------------------------------------------------------------------
4724 DEFAULT_IF_NONE: @DEFAULT_CACHE_LOG@
4725 LOC: Debug::cache_log
4727 Squid administrative logging file.
4729 This is where general information about Squid behavior goes. You can
4730 increase the amount of data logged to this file and how often it is
4731 rotated with "debug_options"
4737 DEFAULT_DOC: Log all critical and important messages.
4738 LOC: Debug::debugOptions
4740 Logging options are set as section,level where each source file
4741 is assigned a unique section. Lower levels result in less
4742 output, Full debugging (level 9) can result in a very large
4743 log file, so be careful.
4745 The magic word "ALL" sets debugging levels for all sections.
4746 The default is to run with "ALL,1" to record important warnings.
4748 The rotate=N option can be used to keep more or less of these logs
4749 than would otherwise be kept by logfile_rotate.
4750 For most uses a single log should be enough to monitor current
4751 events affecting Squid.
4756 LOC: Config.coredump_dir
4757 DEFAULT_IF_NONE: none
4758 DEFAULT_DOC: Use the directory from where Squid was started.
4760 By default Squid leaves core files in the directory from where
4761 it was started. If you set 'coredump_dir' to a directory
4762 that exists, Squid will chdir() to that directory at startup
4763 and coredump files will be left there.
4767 # Leave coredumps in the first cache dir
4768 coredump_dir @DEFAULT_SWAP_DIR@
4774 OPTIONS FOR FTP GATEWAYING
4775 -----------------------------------------------------------------------------
4781 LOC: Config.Ftp.anon_user
4783 If you want the anonymous login password to be more informative
4784 (and enable the use of picky FTP servers), set this to something
4785 reasonable for your domain, like wwwuser@somewhere.net
4787 The reason why this is domainless by default is the
4788 request can be made on the behalf of a user in any domain,
4789 depending on how the cache is used.
4790 Some FTP server also validate the email address is valid
4791 (for example perl.com).
4797 LOC: Config.Ftp.passive
4799 If your firewall does not allow Squid to use passive
4800 connections, turn off this option.
4802 Use of ftp_epsv_all option requires this to be ON.
4808 LOC: Config.Ftp.epsv_all
4810 FTP Protocol extensions permit the use of a special "EPSV ALL" command.
4812 NATs may be able to put the connection on a "fast path" through the
4813 translator, as the EPRT command will never be used and therefore,
4814 translation of the data portion of the segments will never be needed.
4816 When a client only expects to do two-way FTP transfers this may be
4818 If squid finds that it must do a three-way FTP transfer after issuing
4819 an EPSV ALL command, the FTP session will fail.
4821 If you have any doubts about this option do not use it.
4822 Squid will nicely attempt all other connection methods.
4824 Requires ftp_passive to be ON (default) for any effect.
4830 LOC: Config.accessList.ftp_epsv
4832 FTP Protocol extensions permit the use of a special "EPSV" command.
4834 NATs may be able to put the connection on a "fast path" through the
4835 translator using EPSV, as the EPRT command will never be used
4836 and therefore, translation of the data portion of the segments
4837 will never be needed.
4839 EPSV is often required to interoperate with FTP servers on IPv6
4840 networks. On the other hand, it may break some IPv4 servers.
4842 By default, EPSV may try EPSV with any FTP server. To fine tune
4843 that decision, you may restrict EPSV to certain clients or servers
4846 ftp_epsv allow|deny al1 acl2 ...
4848 WARNING: Disabling EPSV may cause problems with external NAT and IPv6.
4850 Only fast ACLs are supported.
4851 Requires ftp_passive to be ON (default) for any effect.
4857 LOC: Config.Ftp.eprt
4859 FTP Protocol extensions permit the use of a special "EPRT" command.
4861 This extension provides a protocol neutral alternative to the
4862 IPv4-only PORT command. When supported it enables active FTP data
4863 channels over IPv6 and efficient NAT handling.
4865 Turning this OFF will prevent EPRT being attempted and will skip
4866 straight to using PORT for IPv4 servers.
4868 Some devices are known to not handle this extension correctly and
4869 may result in crashes. Devices which suport EPRT enough to fail
4870 cleanly will result in Squid attempting PORT anyway. This directive
4871 should only be disabled when EPRT results in device failures.
4873 WARNING: Doing so will convert Squid back to the old behavior with all
4874 the related problems with external NAT devices/layers and IPv4-only FTP.
4877 NAME: ftp_sanitycheck
4880 LOC: Config.Ftp.sanitycheck
4882 For security and data integrity reasons Squid by default performs
4883 sanity checks of the addresses of FTP data connections ensure the
4884 data connection is to the requested server. If you need to allow
4885 FTP connections to servers using another IP address for the data
4886 connection turn this off.
4889 NAME: ftp_telnet_protocol
4892 LOC: Config.Ftp.telnet
4894 The FTP protocol is officially defined to use the telnet protocol
4895 as transport channel for the control connection. However, many
4896 implementations are broken and does not respect this aspect of
4899 If you have trouble accessing files with ASCII code 255 in the
4900 path or similar problems involving this ASCII code you can
4901 try setting this directive to off. If that helps, report to the
4902 operator of the FTP server in question that their FTP server
4903 is broken and does not follow the FTP standard.
4907 OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
4908 -----------------------------------------------------------------------------
4913 DEFAULT: @DEFAULT_DISKD@
4914 LOC: Config.Program.diskd
4916 Specify the location of the diskd executable.
4917 Note this is only useful if you have compiled in
4918 diskd as one of the store io modules.
4921 NAME: unlinkd_program
4924 DEFAULT: @DEFAULT_UNLINKD@
4925 LOC: Config.Program.unlinkd
4927 Specify the location of the executable for file deletion process.
4930 NAME: pinger_program
4933 DEFAULT: @DEFAULT_PINGER@
4936 Specify the location of the executable for the pinger process.
4945 Control whether the pinger is active at run-time.
4946 Enables turning ICMP pinger on and off with a simple
4947 squid -k reconfigure.
4952 OPTIONS FOR URL REWRITING
4953 -----------------------------------------------------------------------------
4956 NAME: url_rewrite_program redirect_program
4958 LOC: Config.Program.redirect
4961 Specify the location of the executable URL rewriter to use.
4962 Since they can perform almost any function there isn't one included.
4964 For each requested URL, the rewriter will receive on line with the format
4966 [channel-ID <SP>] URL [<SP> extras]<NL>
4968 See url_rewrite_extras on how to send "extras" with optional values to
4970 After processing the request the helper must reply using the following format:
4972 [channel-ID <SP>] result [<SP> kv-pairs]
4974 The result code can be:
4976 OK status=30N url="..."
4977 Redirect the URL to the one supplied in 'url='.
4978 'status=' is optional and contains the status code to send
4979 the client in Squids HTTP response. It must be one of the
4980 HTTP redirect status codes: 301, 302, 303, 307, 308.
4981 When no status is given Squid will use 302.
4983 OK rewrite-url="..."
4984 Rewrite the URL to the one supplied in 'rewrite-url='.
4985 The new URL is fetched directly by Squid and returned to
4986 the client as the response to its request.
4989 When neither of url= and rewrite-url= are sent Squid does
4993 Do not change the URL.
4996 An internal error occurred in the helper, preventing
4997 a result being identified. The 'message=' key name is
4998 reserved for delivering a log message.
5001 In addition to the above kv-pairs Squid also understands the following
5002 optional kv-pairs received from URL rewriters:
5004 Associates a TAG with the client TCP connection.
5005 The TAG is treated as a regular annotation but persists across
5006 future requests on the client connection rather than just the
5007 current request. A helper may update the TAG during subsequent
5008 requests be returning a new kv-pair.
5010 When using the concurrency= option the protocol is changed by
5011 introducing a query channel tag in front of the request/response.
5012 The query channel tag is a number between 0 and concurrency-1.
5013 This value must be echoed back unchanged to Squid as the first part
5014 of the response relating to its request.
5016 WARNING: URL re-writing ability should be avoided whenever possible.
5017 Use the URL redirect form of response instead.
5019 Re-write creates a difference in the state held by the client
5020 and server. Possibly causing confusion when the server response
5021 contains snippets of its view state. Embeded URLs, response
5022 and content Location headers, etc. are not re-written by this
5025 By default, a URL rewriter is not used.
5028 NAME: url_rewrite_children redirect_children
5029 TYPE: HelperChildConfig
5030 DEFAULT: 20 startup=0 idle=1 concurrency=0
5031 LOC: Config.redirectChildren
5033 The maximum number of redirector processes to spawn. If you limit
5034 it too few Squid will have to wait for them to process a backlog of
5035 URLs, slowing it down. If you allow too many they will use RAM
5036 and other system resources noticably.
5038 The startup= and idle= options allow some measure of skew in your
5043 Sets a minimum of how many processes are to be spawned when Squid
5044 starts or reconfigures. When set to zero the first request will
5045 cause spawning of the first child process to handle it.
5047 Starting too few will cause an initial slowdown in traffic as Squid
5048 attempts to simultaneously spawn enough processes to cope.
5052 Sets a minimum of how many processes Squid is to try and keep available
5053 at all times. When traffic begins to rise above what the existing
5054 processes can handle this many more will be spawned up to the maximum
5055 configured. A minimum setting of 1 is required.
5059 The number of requests each redirector helper can handle in
5060 parallel. Defaults to 0 which indicates the redirector
5061 is a old-style single threaded redirector.
5063 When this directive is set to a value >= 1 then the protocol
5064 used to communicate with the helper is modified to include
5065 an ID in front of the request/response. The ID from the request
5066 must be echoed back with the response to that request.
5070 Sets the maximum number of queued requests.
5071 If the queued requests exceed queue size and redirector_bypass
5072 configuration option is set, then redirector is bypassed. Otherwise, if
5073 overloading persists squid may abort its operation.
5074 The default value is set to 2*numberofchildren.
5077 NAME: url_rewrite_host_header redirect_rewrites_host_header
5080 LOC: Config.onoff.redir_rewrites_host
5082 To preserve same-origin security policies in browsers and
5083 prevent Host: header forgery by redirectors Squid rewrites
5084 any Host: header in redirected requests.
5086 If you are running an accelerator this may not be a wanted
5087 effect of a redirector. This directive enables you disable
5088 Host: alteration in reverse-proxy traffic.
5090 WARNING: Entries are cached on the result of the URL rewriting
5091 process, so be careful if you have domain-virtual hosts.
5093 WARNING: Squid and other software verifies the URL and Host
5094 are matching, so be careful not to relay through other proxies
5095 or inspecting firewalls with this disabled.
5098 NAME: url_rewrite_access redirector_access
5101 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
5102 LOC: Config.accessList.redirector
5104 If defined, this access list specifies which requests are
5105 sent to the redirector processes.
5107 This clause supports both fast and slow acl types.
5108 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5111 NAME: url_rewrite_bypass redirector_bypass
5113 LOC: Config.onoff.redirector_bypass
5116 When this is 'on', a request will not go through the
5117 redirector if all the helpers are busy. If this is 'off'
5118 and the redirector queue grows too large, Squid will exit
5119 with a FATAL error and ask you to increase the number of
5120 redirectors. You should only enable this if the redirectors
5121 are not critical to your caching system. If you use
5122 redirectors for access control, and you enable this option,
5123 users may have access to pages they should not
5124 be allowed to request.
5125 This options sets default queue-size option of the url_rewrite_children
5129 NAME: url_rewrite_extras
5130 TYPE: TokenOrQuotedString
5131 LOC: Config.redirector_extras
5132 DEFAULT: "%>a/%>A %un %>rm myip=%la myport=%lp"
5134 Specifies a string to be append to request line format for the
5135 rewriter helper. "Quoted" format values may contain spaces and
5136 logformat %macros. In theory, any logformat %macro can be used.
5137 In practice, a %macro expands as a dash (-) if the helper request is
5138 sent before the required macro information is available to Squid.
5141 NAME: url_rewrite_timeout
5142 TYPE: UrlHelperTimeout
5143 LOC: Config.onUrlRewriteTimeout
5145 DEFAULT_DOC: Squid waits for the helper response forever
5147 Squid times active requests to redirector. The timeout value and Squid
5148 reaction to a timed out request are configurable using the following
5151 url_rewrite_timeout timeout time-units on_timeout=<action> [response=<quoted-response>]
5153 supported timeout actions:
5154 fail Squid return a ERR_GATEWAY_FAILURE error page
5156 bypass Do not re-write the URL
5158 retry Send the lookup to the helper again
5160 use_configured_response
5161 Use the <quoted-response> as helper response
5165 OPTIONS FOR STORE ID
5166 -----------------------------------------------------------------------------
5169 NAME: store_id_program storeurl_rewrite_program
5171 LOC: Config.Program.store_id
5174 Specify the location of the executable StoreID helper to use.
5175 Since they can perform almost any function there isn't one included.
5177 For each requested URL, the helper will receive one line with the format
5179 [channel-ID <SP>] URL [<SP> extras]<NL>
5182 After processing the request the helper must reply using the following format:
5184 [channel-ID <SP>] result [<SP> kv-pairs]
5186 The result code can be:
5189 Use the StoreID supplied in 'store-id='.
5192 The default is to use HTTP request URL as the store ID.
5195 An internal error occured in the helper, preventing
5196 a result being identified.
5198 In addition to the above kv-pairs Squid also understands the following
5199 optional kv-pairs received from URL rewriters:
5201 Associates a TAG with the client TCP connection.
5202 Please see url_rewrite_program related documentation for this
5205 Helper programs should be prepared to receive and possibly ignore
5206 additional whitespace-separated tokens on each input line.
5208 When using the concurrency= option the protocol is changed by
5209 introducing a query channel tag in front of the request/response.
5210 The query channel tag is a number between 0 and concurrency-1.
5211 This value must be echoed back unchanged to Squid as the first part
5212 of the response relating to its request.
5214 NOTE: when using StoreID refresh_pattern will apply to the StoreID
5215 returned from the helper and not the URL.
5217 WARNING: Wrong StoreID value returned by a careless helper may result
5218 in the wrong cached response returned to the user.
5220 By default, a StoreID helper is not used.
5223 NAME: store_id_extras
5224 TYPE: TokenOrQuotedString
5225 LOC: Config.storeId_extras
5226 DEFAULT: "%>a/%>A %un %>rm myip=%la myport=%lp"
5228 Specifies a string to be append to request line format for the
5229 StoreId helper. "Quoted" format values may contain spaces and
5230 logformat %macros. In theory, any logformat %macro can be used.
5231 In practice, a %macro expands as a dash (-) if the helper request is
5232 sent before the required macro information is available to Squid.
5235 NAME: store_id_children storeurl_rewrite_children
5236 TYPE: HelperChildConfig
5237 DEFAULT: 20 startup=0 idle=1 concurrency=0
5238 LOC: Config.storeIdChildren
5240 The maximum number of StoreID helper processes to spawn. If you limit
5241 it too few Squid will have to wait for them to process a backlog of
5242 requests, slowing it down. If you allow too many they will use RAM
5243 and other system resources noticably.
5245 The startup= and idle= options allow some measure of skew in your
5250 Sets a minimum of how many processes are to be spawned when Squid
5251 starts or reconfigures. When set to zero the first request will
5252 cause spawning of the first child process to handle it.
5254 Starting too few will cause an initial slowdown in traffic as Squid
5255 attempts to simultaneously spawn enough processes to cope.
5259 Sets a minimum of how many processes Squid is to try and keep available
5260 at all times. When traffic begins to rise above what the existing
5261 processes can handle this many more will be spawned up to the maximum
5262 configured. A minimum setting of 1 is required.
5266 The number of requests each storeID helper can handle in
5267 parallel. Defaults to 0 which indicates the helper
5268 is a old-style single threaded program.
5270 When this directive is set to a value >= 1 then the protocol
5271 used to communicate with the helper is modified to include
5272 an ID in front of the request/response. The ID from the request
5273 must be echoed back with the response to that request.
5277 Sets the maximum number of queued requests.
5278 If the queued requests exceed queue size and store_id_bypass
5279 configuration option is set, then storeID helper is bypassed. Otherwise,
5280 if overloading persists squid may abort its operation.
5281 The default value is set to 2*numberofchildren.
5284 NAME: store_id_access storeurl_rewrite_access
5287 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
5288 LOC: Config.accessList.store_id
5290 If defined, this access list specifies which requests are
5291 sent to the StoreID processes. By default all requests
5294 This clause supports both fast and slow acl types.
5295 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5298 NAME: store_id_bypass storeurl_rewrite_bypass
5300 LOC: Config.onoff.store_id_bypass
5303 When this is 'on', a request will not go through the
5304 helper if all helpers are busy. If this is 'off'
5305 and the helper queue grows too large, Squid will exit
5306 with a FATAL error and ask you to increase the number of
5307 helpers. You should only enable this if the helperss
5308 are not critical to your caching system. If you use
5309 helpers for critical caching components, and you enable this
5310 option, users may not get objects from cache.
5311 This options sets default queue-size option of the store_id_children
5316 OPTIONS FOR TUNING THE CACHE
5317 -----------------------------------------------------------------------------
5320 NAME: cache no_cache
5323 DEFAULT_DOC: By default, this directive is unused and has no effect.
5324 LOC: Config.accessList.noCache
5326 Requests denied by this directive will not be served from the cache
5327 and their responses will not be stored in the cache. This directive
5328 has no effect on other transactions and on already cached responses.
5330 This clause supports both fast and slow acl types.
5331 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5333 This and the two other similar caching directives listed below are
5334 checked at different transaction processing stages, have different
5335 access to response information, affect different cache operations,
5336 and differ in slow ACLs support:
5338 * cache: Checked before Squid makes a hit/miss determination.
5339 No access to reply information!
5340 Denies both serving a hit and storing a miss.
5341 Supports both fast and slow ACLs.
5342 * send_hit: Checked after a hit was detected.
5343 Has access to reply (hit) information.
5344 Denies serving a hit only.
5345 Supports fast ACLs only.
5346 * store_miss: Checked before storing a cachable miss.
5347 Has access to reply (miss) information.
5348 Denies storing a miss only.
5349 Supports fast ACLs only.
5351 If you are not sure which of the three directives to use, apply the
5352 following decision logic:
5354 * If your ACL(s) are of slow type _and_ need response info, redesign.
5355 Squid does not support that particular combination at this time.
5357 * If your directive ACL(s) are of slow type, use "cache"; and/or
5358 * if your directive ACL(s) need no response info, use "cache".
5360 * If you do not want the response cached, use store_miss; and/or
5361 * if you do not want a hit on a cached response, use send_hit.
5367 DEFAULT_DOC: By default, this directive is unused and has no effect.
5368 LOC: Config.accessList.sendHit
5370 Responses denied by this directive will not be served from the cache
5371 (but may still be cached, see store_miss). This directive has no
5372 effect on the responses it allows and on the cached objects.
5374 Please see the "cache" directive for a summary of differences among
5375 store_miss, send_hit, and cache directives.
5377 Unlike the "cache" directive, send_hit only supports fast acl
5378 types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5382 # apply custom Store ID mapping to some URLs
5383 acl MapMe dstdomain .c.example.com
5384 store_id_program ...
5385 store_id_access allow MapMe
5387 # but prevent caching of special responses
5388 # such as 302 redirects that cause StoreID loops
5389 acl Ordinary http_status 200-299
5390 store_miss deny MapMe !Ordinary
5392 # and do not serve any previously stored special responses
5393 # from the cache (in case they were already cached before
5394 # the above store_miss rule was in effect).
5395 send_hit deny MapMe !Ordinary
5401 DEFAULT_DOC: By default, this directive is unused and has no effect.
5402 LOC: Config.accessList.storeMiss
5404 Responses denied by this directive will not be cached (but may still
5405 be served from the cache, see send_hit). This directive has no
5406 effect on the responses it allows and on the already cached responses.
5408 Please see the "cache" directive for a summary of differences among
5409 store_miss, send_hit, and cache directives. See the
5410 send_hit directive for a usage example.
5412 Unlike the "cache" directive, store_miss only supports fast acl
5413 types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5419 LOC: Config.maxStale
5422 This option puts an upper limit on how stale content Squid
5423 will serve from the cache if cache validation fails.
5424 Can be overriden by the refresh_pattern max-stale option.
5427 NAME: refresh_pattern
5428 TYPE: refreshpattern
5432 usage: refresh_pattern [-i] regex min percent max [options]
5434 By default, regular expressions are CASE-SENSITIVE. To make
5435 them case-insensitive, use the -i option.
5437 'Min' is the time (in minutes) an object without an explicit
5438 expiry time should be considered fresh. The recommended
5439 value is 0, any higher values may cause dynamic applications
5440 to be erroneously cached unless the application designer
5441 has taken the appropriate actions.
5443 'Percent' is a percentage of the objects age (time since last
5444 modification age) an object without explicit expiry time
5445 will be considered fresh.
5447 'Max' is an upper limit on how long objects without an explicit
5448 expiry time will be considered fresh.
5450 options: override-expire
5460 override-expire enforces min age even if the server
5461 sent an explicit expiry time (e.g., with the
5462 Expires: header or Cache-Control: max-age). Doing this
5463 VIOLATES the HTTP standard. Enabling this feature
5464 could make you liable for problems which it causes.
5466 Note: override-expire does not enforce staleness - it only extends
5467 freshness / min. If the server returns a Expires time which
5468 is longer than your max time, Squid will still consider
5469 the object fresh for that period of time.
5471 override-lastmod enforces min age even on objects
5472 that were modified recently.
5474 reload-into-ims changes a client no-cache or ``reload''
5475 request for a cached entry into a conditional request using
5476 If-Modified-Since and/or If-None-Match headers, provided the
5477 cached entry has a Last-Modified and/or a strong ETag header.
5478 Doing this VIOLATES the HTTP standard. Enabling this feature
5479 could make you liable for problems which it causes.
5481 ignore-reload ignores a client no-cache or ``reload''
5482 header. Doing this VIOLATES the HTTP standard. Enabling
5483 this feature could make you liable for problems which
5486 ignore-no-store ignores any ``Cache-control: no-store''
5487 headers received from a server. Doing this VIOLATES
5488 the HTTP standard. Enabling this feature could make you
5489 liable for problems which it causes.
5491 ignore-private ignores any ``Cache-control: private''
5492 headers received from a server. Doing this VIOLATES
5493 the HTTP standard. Enabling this feature could make you
5494 liable for problems which it causes.
5496 refresh-ims causes squid to contact the origin server
5497 when a client issues an If-Modified-Since request. This
5498 ensures that the client will receive an updated version
5499 if one is available.
5501 store-stale stores responses even if they don't have explicit
5502 freshness or a validator (i.e., Last-Modified or an ETag)
5503 present, or if they're already stale. By default, Squid will
5504 not cache such responses because they usually can't be
5505 reused. Note that such responses will be stale by default.
5507 max-stale=NN provide a maximum staleness factor. Squid won't
5508 serve objects more stale than this even if it failed to
5509 validate the object. Default: use the max_stale global limit.
5511 Basically a cached object is:
5513 FRESH if expire > now, else STALE
5515 FRESH if lm-factor < percent, else STALE
5519 The refresh_pattern lines are checked in the order listed here.
5520 The first entry which matches is used. If none of the entries
5521 match the default will be used.
5523 Note, you must uncomment all the default lines if you want
5524 to change one. The default setting is only active if none is
5530 # Add any of your own refresh_pattern entries above these.
5532 refresh_pattern ^ftp: 1440 20% 10080
5533 refresh_pattern ^gopher: 1440 0% 1440
5534 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0
5535 refresh_pattern . 0 20% 4320
5539 NAME: quick_abort_min
5543 LOC: Config.quickAbort.min
5546 NAME: quick_abort_max
5550 LOC: Config.quickAbort.max
5553 NAME: quick_abort_pct
5557 LOC: Config.quickAbort.pct
5559 The cache by default continues downloading aborted requests
5560 which are almost completed (less than 16 KB remaining). This
5561 may be undesirable on slow (e.g. SLIP) links and/or very busy
5562 caches. Impatient users may tie up file descriptors and
5563 bandwidth by repeatedly requesting and immediately aborting
5566 When the user aborts a request, Squid will check the
5567 quick_abort values to the amount of data transferred until
5570 If the transfer has less than 'quick_abort_min' KB remaining,
5571 it will finish the retrieval.
5573 If the transfer has more than 'quick_abort_max' KB remaining,
5574 it will abort the retrieval.
5576 If more than 'quick_abort_pct' of the transfer has completed,
5577 it will finish the retrieval.
5579 If you do not want any retrieval to continue after the client
5580 has aborted, set both 'quick_abort_min' and 'quick_abort_max'
5583 If you want retrievals to always continue if they are being
5584 cached set 'quick_abort_min' to '-1 KB'.
5587 NAME: read_ahead_gap
5588 COMMENT: buffer-size
5590 LOC: Config.readAheadGap
5593 The amount of data the cache will buffer ahead of what has been
5594 sent to the client when retrieving an object from another server.
5598 IFDEF: USE_HTTP_VIOLATIONS
5601 LOC: Config.negativeTtl
5604 Set the Default Time-to-Live (TTL) for failed requests.
5605 Certain types of failures (such as "connection refused" and
5606 "404 Not Found") are able to be negatively-cached for a short time.
5607 Modern web servers should provide Expires: header, however if they
5608 do not this can provide a minimum TTL.
5609 The default is not to cache errors with unknown expiry details.
5611 Note that this is different from negative caching of DNS lookups.
5613 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5614 this feature could make you liable for problems which it
5618 NAME: positive_dns_ttl
5621 LOC: Config.positiveDnsTtl
5624 Upper limit on how long Squid will cache positive DNS responses.
5625 Default is 6 hours (360 minutes). This directive must be set
5626 larger than negative_dns_ttl.
5629 NAME: negative_dns_ttl
5632 LOC: Config.negativeDnsTtl
5635 Time-to-Live (TTL) for negative caching of failed DNS lookups.
5636 This also sets the lower cache limit on positive lookups.
5637 Minimum value is 1 second, and it is not recommendable to go
5638 much below 10 seconds.
5641 NAME: range_offset_limit
5642 COMMENT: size [acl acl...]
5644 LOC: Config.rangeOffsetLimit
5647 usage: (size) [units] [[!]aclname]
5649 Sets an upper limit on how far (number of bytes) into the file
5650 a Range request may be to cause Squid to prefetch the whole file.
5651 If beyond this limit, Squid forwards the Range request as it is and
5652 the result is NOT cached.
5654 This is to stop a far ahead range request (lets say start at 17MB)
5655 from making Squid fetch the whole object up to that point before
5656 sending anything to the client.
5658 Multiple range_offset_limit lines may be specified, and they will
5659 be searched from top to bottom on each request until a match is found.
5660 The first match found will be used. If no line matches a request, the
5661 default limit of 0 bytes will be used.
5663 'size' is the limit specified as a number of units.
5665 'units' specifies whether to use bytes, KB, MB, etc.
5666 If no units are specified bytes are assumed.
5668 A size of 0 causes Squid to never fetch more than the
5669 client requested. (default)
5671 A size of 'none' causes Squid to always fetch the object from the
5672 beginning so it may cache the result. (2.0 style)
5674 'aclname' is the name of a defined ACL.
5676 NP: Using 'none' as the byte value here will override any quick_abort settings
5677 that may otherwise apply to the range request. The range request will
5678 be fully fetched from start to finish regardless of the client
5679 actions. This affects bandwidth usage.
5682 NAME: minimum_expiry_time
5685 LOC: Config.minimum_expiry_time
5688 The minimum caching time according to (Expires - Date)
5689 headers Squid honors if the object can't be revalidated.
5690 The default is 60 seconds.
5692 In reverse proxy environments it might be desirable to honor
5693 shorter object lifetimes. It is most likely better to make
5694 your server return a meaningful Last-Modified header however.
5696 In ESI environments where page fragments often have short
5697 lifetimes, this will often be best set to 0.
5700 NAME: store_avg_object_size
5704 LOC: Config.Store.avgObjectSize
5706 Average object size, used to estimate number of objects your
5707 cache can hold. The default is 13 KB.
5709 This is used to pre-seed the cache index memory allocation to
5710 reduce expensive reallocate operations while handling clients
5711 traffic. Too-large values may result in memory allocation during
5712 peak traffic, too-small values will result in wasted memory.
5714 Check the cache manager 'info' report metrics for the real
5715 object sizes seen by your Squid before tuning this.
5718 NAME: store_objects_per_bucket
5721 LOC: Config.Store.objectsPerBucket
5723 Target number of objects per bucket in the store hash table.
5724 Lowering this value increases the total number of buckets and
5725 also the storage maintenance rate. The default is 20.
5730 -----------------------------------------------------------------------------
5733 NAME: request_header_max_size
5737 LOC: Config.maxRequestHeaderSize
5739 This specifies the maximum size for HTTP headers in a request.
5740 Request headers are usually relatively small (about 512 bytes).
5741 Placing a limit on the request header size will catch certain
5742 bugs (for example with persistent connections) and possibly
5743 buffer-overflow or denial-of-service attacks.
5746 NAME: reply_header_max_size
5750 LOC: Config.maxReplyHeaderSize
5752 This specifies the maximum size for HTTP headers in a reply.
5753 Reply headers are usually relatively small (about 512 bytes).
5754 Placing a limit on the reply header size will catch certain
5755 bugs (for example with persistent connections) and possibly
5756 buffer-overflow or denial-of-service attacks.
5759 NAME: request_body_max_size
5763 DEFAULT_DOC: No limit.
5764 LOC: Config.maxRequestBodySize
5766 This specifies the maximum size for an HTTP request body.
5767 In other words, the maximum size of a PUT/POST request.
5768 A user who attempts to send a request with a body larger
5769 than this limit receives an "Invalid Request" error message.
5770 If you set this parameter to a zero (the default), there will
5771 be no limit imposed.
5773 See also client_request_buffer_max_size for an alternative
5774 limitation on client uploads which can be configured.
5777 NAME: client_request_buffer_max_size
5781 LOC: Config.maxRequestBufferSize
5783 This specifies the maximum buffer size of a client request.
5784 It prevents squid eating too much memory when somebody uploads
5789 IFDEF: USE_HTTP_VIOLATIONS
5792 DEFAULT_DOC: Obey RFC 2616.
5793 LOC: Config.accessList.brokenPosts
5795 A list of ACL elements which, if matched, causes Squid to send
5796 an extra CRLF pair after the body of a PUT/POST request.
5798 Some HTTP servers has broken implementations of PUT/POST,
5799 and rely on an extra CRLF pair sent by some WWW clients.
5801 Quote from RFC2616 section 4.1 on this matter:
5803 Note: certain buggy HTTP/1.0 client implementations generate an
5804 extra CRLF's after a POST request. To restate what is explicitly
5805 forbidden by the BNF, an HTTP/1.1 client must not preface or follow
5806 a request with an extra CRLF.
5808 This clause only supports fast acl types.
5809 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5812 acl buggy_server url_regex ^http://....
5813 broken_posts allow buggy_server
5816 NAME: adaptation_uses_indirect_client icap_uses_indirect_client
5819 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_ADAPTATION
5821 LOC: Adaptation::Config::use_indirect_client
5823 Controls whether the indirect client IP address (instead of the direct
5824 client IP address) is passed to adaptation services.
5826 See also: follow_x_forwarded_for adaptation_send_client_ip
5830 IFDEF: USE_HTTP_VIOLATIONS
5834 LOC: Config.onoff.via
5836 If set (default), Squid will include a Via header in requests and
5837 replies as required by RFC2616.
5843 LOC: Config.onoff.ie_refresh
5846 Microsoft Internet Explorer up until version 5.5 Service
5847 Pack 1 has an issue with transparent proxies, wherein it
5848 is impossible to force a refresh. Turning this on provides
5849 a partial fix to the problem, by causing all IMS-REFRESH
5850 requests from older IE versions to check the origin server
5851 for fresh content. This reduces hit ratio by some amount
5852 (~10% in my experience), but allows users to actually get
5853 fresh content when they want it. Note because Squid
5854 cannot tell if the user is using 5.5 or 5.5SP1, the behavior
5855 of 5.5 is unchanged from old versions of Squid (i.e. a
5856 forced refresh is impossible). Newer versions of IE will,
5857 hopefully, continue to have the new behavior and will be
5858 handled based on that assumption. This option defaults to
5859 the old Squid behavior, which is better for hit ratios but
5860 worse for clients using IE, if they need to be able to
5861 force fresh content.
5864 NAME: vary_ignore_expire
5867 LOC: Config.onoff.vary_ignore_expire
5870 Many HTTP servers supporting Vary gives such objects
5871 immediate expiry time with no cache-control header
5872 when requested by a HTTP/1.0 client. This option
5873 enables Squid to ignore such expiry times until
5874 HTTP/1.1 is fully implemented.
5876 WARNING: If turned on this may eventually cause some
5877 varying objects not intended for caching to get cached.
5880 NAME: request_entities
5882 LOC: Config.onoff.request_entities
5885 Squid defaults to deny GET and HEAD requests with request entities,
5886 as the meaning of such requests are undefined in the HTTP standard
5887 even if not explicitly forbidden.
5889 Set this directive to on if you have clients which insists
5890 on sending request entities in GET or HEAD requests. But be warned
5891 that there is server software (both proxies and web servers) which
5892 can fail to properly process this kind of request which may make you
5893 vulnerable to cache pollution attacks if enabled.
5896 NAME: request_header_access
5897 IFDEF: USE_HTTP_VIOLATIONS
5898 TYPE: http_header_access
5899 LOC: Config.request_header_access
5901 DEFAULT_DOC: No limits.
5903 Usage: request_header_access header_name allow|deny [!]aclname ...
5905 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5906 this feature could make you liable for problems which it
5909 This option replaces the old 'anonymize_headers' and the
5910 older 'http_anonymizer' option with something that is much
5911 more configurable. A list of ACLs for each header name allows
5912 removal of specific header fields under specific conditions.
5914 This option only applies to outgoing HTTP request headers (i.e.,
5915 headers sent by Squid to the next HTTP hop such as a cache peer
5916 or an origin server). The option has no effect during cache hit
5917 detection. The equivalent adaptation vectoring point in ICAP
5918 terminology is post-cache REQMOD.
5920 The option is applied to individual outgoing request header
5921 fields. For each request header field F, Squid uses the first
5922 qualifying sets of request_header_access rules:
5924 1. Rules with header_name equal to F's name.
5925 2. Rules with header_name 'Other', provided F's name is not
5926 on the hard-coded list of commonly used HTTP header names.
5927 3. Rules with header_name 'All'.
5929 Within that qualifying rule set, rule ACLs are checked as usual.
5930 If ACLs of an "allow" rule match, the header field is allowed to
5931 go through as is. If ACLs of a "deny" rule match, the header is
5932 removed and request_header_replace is then checked to identify
5933 if the removed header has a replacement. If no rules within the
5934 set have matching ACLs, the header field is left as is.
5936 For example, to achieve the same behavior as the old
5937 'http_anonymizer standard' option, you should use:
5939 request_header_access From deny all
5940 request_header_access Referer deny all
5941 request_header_access User-Agent deny all
5943 Or, to reproduce the old 'http_anonymizer paranoid' feature
5946 request_header_access Authorization allow all
5947 request_header_access Proxy-Authorization allow all
5948 request_header_access Cache-Control allow all
5949 request_header_access Content-Length allow all
5950 request_header_access Content-Type allow all
5951 request_header_access Date allow all
5952 request_header_access Host allow all
5953 request_header_access If-Modified-Since allow all
5954 request_header_access Pragma allow all
5955 request_header_access Accept allow all
5956 request_header_access Accept-Charset allow all
5957 request_header_access Accept-Encoding allow all
5958 request_header_access Accept-Language allow all
5959 request_header_access Connection allow all
5960 request_header_access All deny all
5962 HTTP reply headers are controlled with the reply_header_access directive.
5964 By default, all headers are allowed (no anonymizing is performed).
5967 NAME: reply_header_access
5968 IFDEF: USE_HTTP_VIOLATIONS
5969 TYPE: http_header_access
5970 LOC: Config.reply_header_access
5972 DEFAULT_DOC: No limits.
5974 Usage: reply_header_access header_name allow|deny [!]aclname ...
5976 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5977 this feature could make you liable for problems which it
5980 This option only applies to reply headers, i.e., from the
5981 server to the client.
5983 This is the same as request_header_access, but in the other
5984 direction. Please see request_header_access for detailed
5987 For example, to achieve the same behavior as the old
5988 'http_anonymizer standard' option, you should use:
5990 reply_header_access Server deny all
5991 reply_header_access WWW-Authenticate deny all
5992 reply_header_access Link deny all
5994 Or, to reproduce the old 'http_anonymizer paranoid' feature
5997 reply_header_access Allow allow all
5998 reply_header_access WWW-Authenticate allow all
5999 reply_header_access Proxy-Authenticate allow all
6000 reply_header_access Cache-Control allow all
6001 reply_header_access Content-Encoding allow all
6002 reply_header_access Content-Length allow all
6003 reply_header_access Content-Type allow all
6004 reply_header_access Date allow all
6005 reply_header_access Expires allow all
6006 reply_header_access Last-Modified allow all
6007 reply_header_access Location allow all
6008 reply_header_access Pragma allow all
6009 reply_header_access Content-Language allow all
6010 reply_header_access Retry-After allow all
6011 reply_header_access Title allow all
6012 reply_header_access Content-Disposition allow all
6013 reply_header_access Connection allow all
6014 reply_header_access All deny all
6016 HTTP request headers are controlled with the request_header_access directive.
6018 By default, all headers are allowed (no anonymizing is
6022 NAME: request_header_replace header_replace
6023 IFDEF: USE_HTTP_VIOLATIONS
6024 TYPE: http_header_replace
6025 LOC: Config.request_header_access
6028 Usage: request_header_replace header_name message
6029 Example: request_header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
6031 This option allows you to change the contents of headers
6032 denied with request_header_access above, by replacing them
6033 with some fixed string.
6035 This only applies to request headers, not reply headers.
6037 By default, headers are removed if denied.
6040 NAME: reply_header_replace
6041 IFDEF: USE_HTTP_VIOLATIONS
6042 TYPE: http_header_replace
6043 LOC: Config.reply_header_access
6046 Usage: reply_header_replace header_name message
6047 Example: reply_header_replace Server Foo/1.0
6049 This option allows you to change the contents of headers
6050 denied with reply_header_access above, by replacing them
6051 with some fixed string.
6053 This only applies to reply headers, not request headers.
6055 By default, headers are removed if denied.
6058 NAME: request_header_add
6059 TYPE: HeaderWithAclList
6060 LOC: Config.request_header_add
6063 Usage: request_header_add field-name field-value acl1 [acl2] ...
6064 Example: request_header_add X-Client-CA "CA=%ssl::>cert_issuer" all
6066 This option adds header fields to outgoing HTTP requests (i.e.,
6067 request headers sent by Squid to the next HTTP hop such as a
6068 cache peer or an origin server). The option has no effect during
6069 cache hit detection. The equivalent adaptation vectoring point
6070 in ICAP terminology is post-cache REQMOD.
6072 Field-name is a token specifying an HTTP header name. If a
6073 standard HTTP header name is used, Squid does not check whether
6074 the new header conflicts with any existing headers or violates
6075 HTTP rules. If the request to be modified already contains a
6076 field with the same name, the old field is preserved but the
6077 header field values are not merged.
6079 Field-value is either a token or a quoted string. If quoted
6080 string format is used, then the surrounding quotes are removed
6081 while escape sequences and %macros are processed.
6083 In theory, all of the logformat codes can be used as %macros.
6084 However, unlike logging (which happens at the very end of
6085 transaction lifetime), the transaction may not yet have enough
6086 information to expand a macro when the new header value is needed.
6087 And some information may already be available to Squid but not yet
6088 committed where the macro expansion code can access it (report
6089 such instances!). The macro will be expanded into a single dash
6090 ('-') in such cases. Not all macros have been tested.
6092 One or more Squid ACLs may be specified to restrict header
6093 injection to matching requests. As always in squid.conf, all
6094 ACLs in an option ACL list must be satisfied for the insertion
6095 to happen. The request_header_add option supports fast ACLs
6104 This option used to log custom information about the master
6105 transaction. For example, an admin may configure Squid to log
6106 which "user group" the transaction belongs to, where "user group"
6107 will be determined based on a set of ACLs and not [just]
6108 authentication information.
6109 Values of key/value pairs can be logged using %{key}note macros:
6111 note key value acl ...
6112 logformat myFormat ... %{key}note ...
6115 NAME: relaxed_header_parser
6116 COMMENT: on|off|warn
6118 LOC: Config.onoff.relaxed_header_parser
6121 In the default "on" setting Squid accepts certain forms
6122 of non-compliant HTTP messages where it is unambiguous
6123 what the sending application intended even if the message
6124 is not correctly formatted. The messages is then normalized
6125 to the correct form when forwarded by Squid.
6127 If set to "warn" then a warning will be emitted in cache.log
6128 each time such HTTP error is encountered.
6130 If set to "off" then such HTTP errors will cause the request
6131 or response to be rejected.
6134 NAME: collapsed_forwarding
6137 LOC: Config.onoff.collapsed_forwarding
6140 This option controls whether Squid is allowed to merge multiple
6141 potentially cachable requests for the same URI before Squid knows
6142 whether the response is going to be cachable.
6144 This feature is disabled by default: Enabling collapsed forwarding
6145 needlessly delays forwarding requests that look cachable (when they are
6146 collapsed) but then need to be forwarded individually anyway because
6147 they end up being for uncachable content. However, in some cases, such
6148 as accelleration of highly cachable content with periodic or groupped
6149 expiration times, the gains from collapsing [large volumes of
6150 simultenous refresh requests] outweigh losses from such delays.
6155 -----------------------------------------------------------------------------
6158 NAME: forward_timeout
6161 LOC: Config.Timeout.forward
6164 This parameter specifies how long Squid should at most attempt in
6165 finding a forwarding path for the request before giving up.
6168 NAME: connect_timeout
6171 LOC: Config.Timeout.connect
6174 This parameter specifies how long to wait for the TCP connect to
6175 the requested server or peer to complete before Squid should
6176 attempt to find another path where to forward the request.
6179 NAME: peer_connect_timeout
6182 LOC: Config.Timeout.peer_connect
6185 This parameter specifies how long to wait for a pending TCP
6186 connection to a peer cache. The default is 30 seconds. You
6187 may also set different timeout values for individual neighbors
6188 with the 'connect-timeout' option on a 'cache_peer' line.
6194 LOC: Config.Timeout.read
6197 Applied on peer server connections.
6199 After each successful read(), the timeout will be extended by this
6200 amount. If no data is read again after this amount of time,
6201 the request is aborted and logged with ERR_READ_TIMEOUT.
6203 The default is 15 minutes.
6209 LOC: Config.Timeout.write
6212 This timeout is tracked for all connections that have data
6213 available for writing and are waiting for the socket to become
6214 ready. After each successful write, the timeout is extended by
6215 the configured amount. If Squid has data to write but the
6216 connection is not ready for the configured duration, the
6217 transaction associated with the connection is terminated. The
6218 default is 15 minutes.
6221 NAME: request_timeout
6223 LOC: Config.Timeout.request
6226 How long to wait for complete HTTP request headers after initial
6227 connection establishment.
6230 NAME: request_start_timeout
6232 LOC: Config.Timeout.request_start_timeout
6235 How long to wait for the first request byte after initial
6236 connection establishment.
6239 NAME: client_idle_pconn_timeout persistent_request_timeout
6241 LOC: Config.Timeout.clientIdlePconn
6244 How long to wait for the next HTTP request on a persistent
6245 client connection after the previous request completes.
6248 NAME: ftp_client_idle_timeout
6250 LOC: Config.Timeout.ftpClientIdle
6253 How long to wait for an FTP request on a connection to Squid ftp_port.
6254 Many FTP clients do not deal with idle connection closures well,
6255 necessitating a longer default timeout than client_idle_pconn_timeout
6256 used for incoming HTTP requests.
6259 NAME: client_lifetime
6262 LOC: Config.Timeout.lifetime
6265 The maximum amount of time a client (browser) is allowed to
6266 remain connected to the cache process. This protects the Cache
6267 from having a lot of sockets (and hence file descriptors) tied up
6268 in a CLOSE_WAIT state from remote clients that go away without
6269 properly shutting down (either because of a network failure or
6270 because of a poor client implementation). The default is one
6273 NOTE: The default value is intended to be much larger than any
6274 client would ever need to be connected to your cache. You
6275 should probably change client_lifetime only as a last resort.
6276 If you seem to have many client connections tying up
6277 filedescriptors, we recommend first tuning the read_timeout,
6278 request_timeout, persistent_request_timeout and quick_abort values.
6281 NAME: pconn_lifetime
6284 LOC: Config.Timeout.pconnLifetime
6287 Desired maximum lifetime of a persistent connection.
6288 When set, Squid will close a now-idle persistent connection that
6289 exceeded configured lifetime instead of moving the connection into
6290 the idle connection pool (or equivalent). No effect on ongoing/active
6291 transactions. Connection lifetime is the time period from the
6292 connection acceptance or opening time until "now".
6294 This limit is useful in environments with long-lived connections
6295 where Squid configuration or environmental factors change during a
6296 single connection lifetime. If unrestricted, some connections may
6297 last for hours and even days, ignoring those changes that should
6298 have affected their behavior or their existence.
6300 Currently, a new lifetime value supplied via Squid reconfiguration
6301 has no effect on already idle connections unless they become busy.
6303 When set to '0' this limit is not used.
6306 NAME: half_closed_clients
6308 LOC: Config.onoff.half_closed_clients
6311 Some clients may shutdown the sending side of their TCP
6312 connections, while leaving their receiving sides open. Sometimes,
6313 Squid can not tell the difference between a half-closed and a
6314 fully-closed TCP connection.
6316 By default, Squid will immediately close client connections when
6317 read(2) returns "no more data to read."
6319 Change this option to 'on' and Squid will keep open connections
6320 until a read(2) or write(2) on the socket returns an error.
6321 This may show some benefits for reverse proxies. But if not
6322 it is recommended to leave OFF.
6325 NAME: server_idle_pconn_timeout pconn_timeout
6327 LOC: Config.Timeout.serverIdlePconn
6330 Timeout for idle persistent connections to servers and other
6337 LOC: Ident::TheConfig.timeout
6340 Maximum time to wait for IDENT lookups to complete.
6342 If this is too high, and you enabled IDENT lookups from untrusted
6343 users, you might be susceptible to denial-of-service by having
6344 many ident requests going at once.
6347 NAME: shutdown_lifetime
6350 LOC: Config.shutdownLifetime
6353 When SIGTERM or SIGHUP is received, the cache is put into
6354 "shutdown pending" mode until all active sockets are closed.
6355 This value is the lifetime to set for all open descriptors
6356 during shutdown mode. Any active clients after this many
6357 seconds will receive a 'timeout' message.
6361 ADMINISTRATIVE PARAMETERS
6362 -----------------------------------------------------------------------------
6368 LOC: Config.adminEmail
6370 Email-address of local cache manager who will receive
6371 mail if the cache dies. The default is "webmaster".
6377 LOC: Config.EmailFrom
6379 From: email-address for mail sent when the cache dies.
6380 The default is to use 'squid@unique_hostname'.
6382 See also: unique_hostname directive.
6388 LOC: Config.EmailProgram
6390 Email program used to send mail if the cache dies.
6391 The default is "mail". The specified program must comply
6392 with the standard Unix mail syntax:
6393 mail-program recipient < mailfile
6395 Optional command line options can be specified.
6398 NAME: cache_effective_user
6400 DEFAULT: @DEFAULT_CACHE_EFFECTIVE_USER@
6401 LOC: Config.effectiveUser
6403 If you start Squid as root, it will change its effective/real
6404 UID/GID to the user specified below. The default is to change
6405 to UID of @DEFAULT_CACHE_EFFECTIVE_USER@.
6406 see also; cache_effective_group
6409 NAME: cache_effective_group
6412 DEFAULT_DOC: Use system group memberships of the cache_effective_user account
6413 LOC: Config.effectiveGroup
6415 Squid sets the GID to the effective user's default group ID
6416 (taken from the password file) and supplementary group list
6417 from the groups membership.
6419 If you want Squid to run with a specific GID regardless of
6420 the group memberships of the effective user then set this
6421 to the group (or GID) you want Squid to run as. When set
6422 all other group privileges of the effective user are ignored
6423 and only this GID is effective. If Squid is not started as
6424 root the user starting Squid MUST be member of the specified
6427 This option is not recommended by the Squid Team.
6428 Our preference is for administrators to configure a secure
6429 user account for squid with UID/GID matching system policies.
6432 NAME: httpd_suppress_version_string
6436 LOC: Config.onoff.httpd_suppress_version_string
6438 Suppress Squid version string info in HTTP headers and HTML error pages.
6441 NAME: visible_hostname
6443 LOC: Config.visibleHostname
6445 DEFAULT_DOC: Automatically detect the system host name
6447 If you want to present a special hostname in error messages, etc,
6448 define this. Otherwise, the return value of gethostname()
6449 will be used. If you have multiple caches in a cluster and
6450 get errors about IP-forwarding you must set them to have individual
6451 names with this setting.
6454 NAME: unique_hostname
6456 LOC: Config.uniqueHostname
6458 DEFAULT_DOC: Copy the value from visible_hostname
6460 If you want to have multiple machines with the same
6461 'visible_hostname' you must give each machine a different
6462 'unique_hostname' so forwarding loops can be detected.
6465 NAME: hostname_aliases
6467 LOC: Config.hostnameAliases
6470 A list of other DNS names your cache has.
6478 Minimum umask which should be enforced while the proxy
6479 is running, in addition to the umask set at startup.
6481 For a traditional octal representation of umasks, start
6486 OPTIONS FOR THE CACHE REGISTRATION SERVICE
6487 -----------------------------------------------------------------------------
6489 This section contains parameters for the (optional) cache
6490 announcement service. This service is provided to help
6491 cache administrators locate one another in order to join or
6492 create cache hierarchies.
6494 An 'announcement' message is sent (via UDP) to the registration
6495 service by Squid. By default, the announcement message is NOT
6496 SENT unless you enable it with 'announce_period' below.
6498 The announcement message includes your hostname, plus the
6499 following information from this configuration file:
6505 All current information is processed regularly and made
6506 available on the Web at http://www.ircache.net/Cache/Tracker/.
6509 NAME: announce_period
6511 LOC: Config.Announce.period
6513 DEFAULT_DOC: Announcement messages disabled.
6515 This is how frequently to send cache announcements.
6517 To enable announcing your cache, just set an announce period.
6520 announce_period 1 day
6525 DEFAULT: tracker.ircache.net
6526 LOC: Config.Announce.host
6528 Set the hostname where announce registration messages will be sent.
6530 See also announce_port and announce_file
6536 LOC: Config.Announce.file
6538 The contents of this file will be included in the announce
6539 registration messages.
6545 LOC: Config.Announce.port
6547 Set the port where announce registration messages will be sent.
6549 See also announce_host and announce_file
6553 HTTPD-ACCELERATOR OPTIONS
6554 -----------------------------------------------------------------------------
6557 NAME: httpd_accel_surrogate_id
6560 DEFAULT_DOC: visible_hostname is used if no specific ID is set.
6561 LOC: Config.Accel.surrogate_id
6563 Surrogates (http://www.esi.org/architecture_spec_1.0.html)
6564 need an identification token to allow control targeting. Because
6565 a farm of surrogates may all perform the same tasks, they may share
6566 an identification token.
6569 NAME: http_accel_surrogate_remote
6573 LOC: Config.onoff.surrogate_is_remote
6575 Remote surrogates (such as those in a CDN) honour the header
6576 "Surrogate-Control: no-store-remote".
6578 Set this to on to have squid behave as a remote surrogate.
6582 IFDEF: USE_SQUID_ESI
6583 COMMENT: libxml2|expat|custom
6585 LOC: ESIParser::Type
6588 ESI markup is not strictly XML compatible. The custom ESI parser
6589 will give higher performance, but cannot handle non ASCII character
6594 DELAY POOL PARAMETERS
6595 -----------------------------------------------------------------------------
6599 TYPE: delay_pool_count
6601 IFDEF: USE_DELAY_POOLS
6604 This represents the number of delay pools to be used. For example,
6605 if you have one class 2 delay pool and one class 3 delays pool, you
6606 have a total of 2 delay pools.
6608 See also delay_parameters, delay_class, delay_access for pool
6609 configuration details.
6613 TYPE: delay_pool_class
6615 IFDEF: USE_DELAY_POOLS
6618 This defines the class of each delay pool. There must be exactly one
6619 delay_class line for each delay pool. For example, to define two
6620 delay pools, one of class 2 and one of class 3, the settings above
6624 delay_pools 4 # 4 delay pools
6625 delay_class 1 2 # pool 1 is a class 2 pool
6626 delay_class 2 3 # pool 2 is a class 3 pool
6627 delay_class 3 4 # pool 3 is a class 4 pool
6628 delay_class 4 5 # pool 4 is a class 5 pool
6630 The delay pool classes are:
6632 class 1 Everything is limited by a single aggregate
6635 class 2 Everything is limited by a single aggregate
6636 bucket as well as an "individual" bucket chosen
6637 from bits 25 through 32 of the IPv4 address.
6639 class 3 Everything is limited by a single aggregate
6640 bucket as well as a "network" bucket chosen
6641 from bits 17 through 24 of the IP address and a
6642 "individual" bucket chosen from bits 17 through
6643 32 of the IPv4 address.
6645 class 4 Everything in a class 3 delay pool, with an
6646 additional limit on a per user basis. This
6647 only takes effect if the username is established
6648 in advance - by forcing authentication in your
6651 class 5 Requests are grouped according their tag (see
6652 external_acl's tag= reply).
6655 Each pool also requires a delay_parameters directive to configure the pool size
6656 and speed limits used whenever the pool is applied to a request. Along with
6657 a set of delay_access directives to determine when it is used.
6659 NOTE: If an IP address is a.b.c.d
6660 -> bits 25 through 32 are "d"
6661 -> bits 17 through 24 are "c"
6662 -> bits 17 through 32 are "c * 256 + d"
6664 NOTE-2: Due to the use of bitmasks in class 2,3,4 pools they only apply to
6665 IPv4 traffic. Class 1 and 5 pools may be used with IPv6 traffic.
6667 This clause only supports fast acl types.
6668 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6670 See also delay_parameters and delay_access.
6674 TYPE: delay_pool_access
6676 DEFAULT_DOC: Deny using the pool, unless allow rules exist in squid.conf for the pool.
6677 IFDEF: USE_DELAY_POOLS
6680 This is used to determine which delay pool a request falls into.
6682 delay_access is sorted per pool and the matching starts with pool 1,
6683 then pool 2, ..., and finally pool N. The first delay pool where the
6684 request is allowed is selected for the request. If it does not allow
6685 the request to any pool then the request is not delayed (default).
6687 For example, if you want some_big_clients in delay
6688 pool 1 and lotsa_little_clients in delay pool 2:
6690 delay_access 1 allow some_big_clients
6691 delay_access 1 deny all
6692 delay_access 2 allow lotsa_little_clients
6693 delay_access 2 deny all
6694 delay_access 3 allow authenticated_clients
6696 See also delay_parameters and delay_class.
6700 NAME: delay_parameters
6701 TYPE: delay_pool_rates
6703 IFDEF: USE_DELAY_POOLS
6706 This defines the parameters for a delay pool. Each delay pool has
6707 a number of "buckets" associated with it, as explained in the
6708 description of delay_class.
6710 For a class 1 delay pool, the syntax is:
6712 delay_parameters pool aggregate
6714 For a class 2 delay pool:
6716 delay_parameters pool aggregate individual
6718 For a class 3 delay pool:
6720 delay_parameters pool aggregate network individual
6722 For a class 4 delay pool:
6724 delay_parameters pool aggregate network individual user
6726 For a class 5 delay pool:
6728 delay_parameters pool tagrate
6730 The option variables are:
6732 pool a pool number - ie, a number between 1 and the
6733 number specified in delay_pools as used in
6736 aggregate the speed limit parameters for the aggregate bucket
6739 individual the speed limit parameters for the individual
6740 buckets (class 2, 3).
6742 network the speed limit parameters for the network buckets
6745 user the speed limit parameters for the user buckets
6748 tagrate the speed limit parameters for the tag buckets
6751 A pair of delay parameters is written restore/maximum, where restore is
6752 the number of bytes (not bits - modem and network speeds are usually
6753 quoted in bits) per second placed into the bucket, and maximum is the
6754 maximum number of bytes which can be in the bucket at any time.
6756 There must be one delay_parameters line for each delay pool.
6759 For example, if delay pool number 1 is a class 2 delay pool as in the
6760 above example, and is being used to strictly limit each host to 64Kbit/sec
6761 (plus overheads), with no overall limit, the line is:
6763 delay_parameters 1 none 8000/8000
6765 Note that 8 x 8000 KByte/sec -> 64Kbit/sec.
6767 Note that the word 'none' is used to represent no limit.
6770 And, if delay pool number 2 is a class 3 delay pool as in the above
6771 example, and you want to limit it to a total of 256Kbit/sec (strict limit)
6772 with each 8-bit network permitted 64Kbit/sec (strict limit) and each
6773 individual host permitted 4800bit/sec with a bucket maximum size of 64Kbits
6774 to permit a decent web page to be downloaded at a decent speed
6775 (if the network is not being limited due to overuse) but slow down
6776 large downloads more significantly:
6778 delay_parameters 2 32000/32000 8000/8000 600/8000
6780 Note that 8 x 32000 KByte/sec -> 256Kbit/sec.
6781 8 x 8000 KByte/sec -> 64Kbit/sec.
6782 8 x 600 Byte/sec -> 4800bit/sec.
6785 Finally, for a class 4 delay pool as in the example - each user will
6786 be limited to 128Kbits/sec no matter how many workstations they are logged into.:
6788 delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000
6791 See also delay_class and delay_access.
6795 NAME: delay_initial_bucket_level
6796 COMMENT: (percent, 0-100)
6799 IFDEF: USE_DELAY_POOLS
6800 LOC: Config.Delay.initial
6802 The initial bucket percentage is used to determine how much is put
6803 in each bucket when squid starts, is reconfigured, or first notices
6804 a host accessing it (in class 2 and class 3, individual hosts and
6805 networks only have buckets associated with them once they have been
6810 CLIENT DELAY POOL PARAMETERS
6811 -----------------------------------------------------------------------------
6814 NAME: client_delay_pools
6815 TYPE: client_delay_pool_count
6817 IFDEF: USE_DELAY_POOLS
6818 LOC: Config.ClientDelay
6820 This option specifies the number of client delay pools used. It must
6821 preceed other client_delay_* options.
6824 client_delay_pools 2
6826 See also client_delay_parameters and client_delay_access.
6829 NAME: client_delay_initial_bucket_level
6830 COMMENT: (percent, 0-no_limit)
6833 IFDEF: USE_DELAY_POOLS
6834 LOC: Config.ClientDelay.initial
6836 This option determines the initial bucket size as a percentage of
6837 max_bucket_size from client_delay_parameters. Buckets are created
6838 at the time of the "first" connection from the matching IP. Idle
6839 buckets are periodically deleted up.
6841 You can specify more than 100 percent but note that such "oversized"
6842 buckets are not refilled until their size goes down to max_bucket_size
6843 from client_delay_parameters.
6846 client_delay_initial_bucket_level 50
6849 NAME: client_delay_parameters
6850 TYPE: client_delay_pool_rates
6852 IFDEF: USE_DELAY_POOLS
6853 LOC: Config.ClientDelay
6856 This option configures client-side bandwidth limits using the
6859 client_delay_parameters pool speed_limit max_bucket_size
6861 pool is an integer ID used for client_delay_access matching.
6863 speed_limit is bytes added to the bucket per second.
6865 max_bucket_size is the maximum size of a bucket, enforced after any
6866 speed_limit additions.
6868 Please see the delay_parameters option for more information and
6872 client_delay_parameters 1 1024 2048
6873 client_delay_parameters 2 51200 16384
6875 See also client_delay_access.
6879 NAME: client_delay_access
6880 TYPE: client_delay_pool_access
6882 DEFAULT_DOC: Deny use of the pool, unless allow rules exist in squid.conf for the pool.
6883 IFDEF: USE_DELAY_POOLS
6884 LOC: Config.ClientDelay
6886 This option determines the client-side delay pool for the
6889 client_delay_access pool_ID allow|deny acl_name
6891 All client_delay_access options are checked in their pool ID
6892 order, starting with pool 1. The first checked pool with allowed
6893 request is selected for the request. If no ACL matches or there
6894 are no client_delay_access options, the request bandwidth is not
6897 The ACL-selected pool is then used to find the
6898 client_delay_parameters for the request. Client-side pools are
6899 not used to aggregate clients. Clients are always aggregated
6900 based on their source IP addresses (one bucket per source IP).
6902 This clause only supports fast acl types.
6903 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6904 Additionally, only the client TCP connection details are available.
6905 ACLs testing HTTP properties will not work.
6907 Please see delay_access for more examples.
6910 client_delay_access 1 allow low_rate_network
6911 client_delay_access 2 allow vips_network
6914 See also client_delay_parameters and client_delay_pools.
6918 WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS
6919 -----------------------------------------------------------------------------
6924 LOC: Config.Wccp.router
6926 DEFAULT_DOC: WCCP disabled.
6929 Use this option to define your WCCP ``home'' router for
6932 wccp_router supports a single WCCP(v1) router
6934 wccp2_router supports multiple WCCPv2 routers
6936 only one of the two may be used at the same time and defines
6937 which version of WCCP to use.
6941 TYPE: IpAddress_list
6942 LOC: Config.Wccp2.router
6944 DEFAULT_DOC: WCCPv2 disabled.
6947 Use this option to define your WCCP ``home'' router for
6950 wccp_router supports a single WCCP(v1) router
6952 wccp2_router supports multiple WCCPv2 routers
6954 only one of the two may be used at the same time and defines
6955 which version of WCCP to use.
6960 LOC: Config.Wccp.version
6964 This directive is only relevant if you need to set up WCCP(v1)
6965 to some very old and end-of-life Cisco routers. In all other
6966 setups it must be left unset or at the default setting.
6967 It defines an internal version in the WCCP(v1) protocol,
6968 with version 4 being the officially documented protocol.
6970 According to some users, Cisco IOS 11.2 and earlier only
6971 support WCCP version 3. If you're using that or an earlier
6972 version of IOS, you may need to change this value to 3, otherwise
6973 do not specify this parameter.
6976 NAME: wccp2_rebuild_wait
6978 LOC: Config.Wccp2.rebuildwait
6982 If this is enabled Squid will wait for the cache dir rebuild to finish
6983 before sending the first wccp2 HereIAm packet
6986 NAME: wccp2_forwarding_method
6988 LOC: Config.Wccp2.forwarding_method
6992 WCCP2 allows the setting of forwarding methods between the
6993 router/switch and the cache. Valid values are as follows:
6995 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
6996 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
6998 Currently (as of IOS 12.4) cisco routers only support GRE.
6999 Cisco switches only support the L2 redirect assignment method.
7002 NAME: wccp2_return_method
7004 LOC: Config.Wccp2.return_method
7008 WCCP2 allows the setting of return methods between the
7009 router/switch and the cache for packets that the cache
7010 decides not to handle. Valid values are as follows:
7012 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
7013 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
7015 Currently (as of IOS 12.4) cisco routers only support GRE.
7016 Cisco switches only support the L2 redirect assignment.
7018 If the "ip wccp redirect exclude in" command has been
7019 enabled on the cache interface, then it is still safe for
7020 the proxy server to use a l2 redirect method even if this
7021 option is set to GRE.
7024 NAME: wccp2_assignment_method
7026 LOC: Config.Wccp2.assignment_method
7030 WCCP2 allows the setting of methods to assign the WCCP hash
7031 Valid values are as follows:
7033 hash - Hash assignment
7034 mask - Mask assignment
7036 As a general rule, cisco routers support the hash assignment method
7037 and cisco switches support the mask assignment method.
7042 LOC: Config.Wccp2.info
7043 DEFAULT_IF_NONE: standard 0
7044 DEFAULT_DOC: Use the 'web-cache' standard service.
7047 WCCP2 allows for multiple traffic services. There are two
7048 types: "standard" and "dynamic". The standard type defines
7049 one service id - http (id 0). The dynamic service ids can be from
7050 51 to 255 inclusive. In order to use a dynamic service id
7051 one must define the type of traffic to be redirected; this is done
7052 using the wccp2_service_info option.
7054 The "standard" type does not require a wccp2_service_info option,
7055 just specifying the service id will suffice.
7057 MD5 service authentication can be enabled by adding
7058 "password=<password>" to the end of this service declaration.
7062 wccp2_service standard 0 # for the 'web-cache' standard service
7063 wccp2_service dynamic 80 # a dynamic service type which will be
7064 # fleshed out with subsequent options.
7065 wccp2_service standard 0 password=foo
7068 NAME: wccp2_service_info
7069 TYPE: wccp2_service_info
7070 LOC: Config.Wccp2.info
7074 Dynamic WCCPv2 services require further information to define the
7075 traffic you wish to have diverted.
7079 wccp2_service_info <id> protocol=<protocol> flags=<flag>,<flag>..
7080 priority=<priority> ports=<port>,<port>..
7082 The relevant WCCPv2 flags:
7083 + src_ip_hash, dst_ip_hash
7084 + source_port_hash, dst_port_hash
7085 + src_ip_alt_hash, dst_ip_alt_hash
7086 + src_port_alt_hash, dst_port_alt_hash
7089 The port list can be one to eight entries.
7093 wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source
7094 priority=240 ports=80
7096 Note: the service id must have been defined by a previous
7097 'wccp2_service dynamic <id>' entry.
7102 LOC: Config.Wccp2.weight
7106 Each cache server gets assigned a set of the destination
7107 hash proportional to their weight.
7112 LOC: Config.Wccp.address
7114 DEFAULT_DOC: Address selected by the operating system.
7117 Use this option if you require WCCPv2 to use a specific
7120 The default behavior is to not bind to any specific address.
7125 LOC: Config.Wccp2.address
7127 DEFAULT_DOC: Address selected by the operating system.
7130 Use this option if you require WCCP to use a specific
7133 The default behavior is to not bind to any specific address.
7137 PERSISTENT CONNECTION HANDLING
7138 -----------------------------------------------------------------------------
7140 Also see "pconn_timeout" in the TIMEOUTS section
7143 NAME: client_persistent_connections
7145 LOC: Config.onoff.client_pconns
7148 Persistent connection support for clients.
7149 Squid uses persistent connections (when allowed). You can use
7150 this option to disable persistent connections with clients.
7153 NAME: server_persistent_connections
7155 LOC: Config.onoff.server_pconns
7158 Persistent connection support for servers.
7159 Squid uses persistent connections (when allowed). You can use
7160 this option to disable persistent connections with servers.
7163 NAME: persistent_connection_after_error
7165 LOC: Config.onoff.error_pconns
7168 With this directive the use of persistent connections after
7169 HTTP errors can be disabled. Useful if you have clients
7170 who fail to handle errors on persistent connections proper.
7173 NAME: detect_broken_pconn
7175 LOC: Config.onoff.detect_broken_server_pconns
7178 Some servers have been found to incorrectly signal the use
7179 of HTTP/1.0 persistent connections even on replies not
7180 compatible, causing significant delays. This server problem
7181 has mostly been seen on redirects.
7183 By enabling this directive Squid attempts to detect such
7184 broken replies and automatically assume the reply is finished
7185 after 10 seconds timeout.
7189 CACHE DIGEST OPTIONS
7190 -----------------------------------------------------------------------------
7193 NAME: digest_generation
7194 IFDEF: USE_CACHE_DIGESTS
7196 LOC: Config.onoff.digest_generation
7199 This controls whether the server will generate a Cache Digest
7200 of its contents. By default, Cache Digest generation is
7201 enabled if Squid is compiled with --enable-cache-digests defined.
7204 NAME: digest_bits_per_entry
7205 IFDEF: USE_CACHE_DIGESTS
7207 LOC: Config.digest.bits_per_entry
7210 This is the number of bits of the server's Cache Digest which
7211 will be associated with the Digest entry for a given HTTP
7212 Method and URL (public key) combination. The default is 5.
7215 NAME: digest_rebuild_period
7216 IFDEF: USE_CACHE_DIGESTS
7219 LOC: Config.digest.rebuild_period
7222 This is the wait time between Cache Digest rebuilds.
7225 NAME: digest_rewrite_period
7227 IFDEF: USE_CACHE_DIGESTS
7229 LOC: Config.digest.rewrite_period
7232 This is the wait time between Cache Digest writes to
7236 NAME: digest_swapout_chunk_size
7239 IFDEF: USE_CACHE_DIGESTS
7240 LOC: Config.digest.swapout_chunk_size
7243 This is the number of bytes of the Cache Digest to write to
7244 disk at a time. It defaults to 4096 bytes (4KB), the Squid
7248 NAME: digest_rebuild_chunk_percentage
7249 COMMENT: (percent, 0-100)
7250 IFDEF: USE_CACHE_DIGESTS
7252 LOC: Config.digest.rebuild_chunk_percentage
7255 This is the percentage of the Cache Digest to be scanned at a
7256 time. By default it is set to 10% of the Cache Digest.
7261 -----------------------------------------------------------------------------
7266 LOC: Config.Port.snmp
7268 DEFAULT_DOC: SNMP disabled.
7271 The port number where Squid listens for SNMP requests. To enable
7272 SNMP support set this to a suitable port number. Port number
7273 3401 is often used for the Squid SNMP agent. By default it's
7274 set to "0" (disabled)
7282 LOC: Config.accessList.snmp
7284 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
7287 Allowing or denying access to the SNMP port.
7289 All access to the agent is denied by default.
7292 snmp_access allow|deny [!]aclname ...
7294 This clause only supports fast acl types.
7295 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7298 snmp_access allow snmppublic localhost
7299 snmp_access deny all
7302 NAME: snmp_incoming_address
7304 LOC: Config.Addrs.snmp_incoming
7306 DEFAULT_DOC: Accept SNMP packets from all machine interfaces.
7309 Just like 'udp_incoming_address', but for the SNMP port.
7311 snmp_incoming_address is used for the SNMP socket receiving
7312 messages from SNMP agents.
7314 The default snmp_incoming_address is to listen on all
7315 available network interfaces.
7318 NAME: snmp_outgoing_address
7320 LOC: Config.Addrs.snmp_outgoing
7322 DEFAULT_DOC: Use snmp_incoming_address or an address selected by the operating system.
7325 Just like 'udp_outgoing_address', but for the SNMP port.
7327 snmp_outgoing_address is used for SNMP packets returned to SNMP
7330 If snmp_outgoing_address is not set it will use the same socket
7331 as snmp_incoming_address. Only change this if you want to have
7332 SNMP replies sent using another address than where this Squid
7333 listens for SNMP queries.
7335 NOTE, snmp_incoming_address and snmp_outgoing_address can not have
7336 the same value since they both use the same port.
7341 -----------------------------------------------------------------------------
7344 NAME: icp_port udp_port
7347 DEFAULT_DOC: ICP disabled.
7348 LOC: Config.Port.icp
7350 The port number where Squid sends and receives ICP queries to
7351 and from neighbor caches. The standard UDP port for ICP is 3130.
7354 icp_port @DEFAULT_ICP_PORT@
7361 DEFAULT_DOC: HTCP disabled.
7362 LOC: Config.Port.htcp
7364 The port number where Squid sends and receives HTCP queries to
7365 and from neighbor caches. To turn it on you want to set it to
7372 NAME: log_icp_queries
7376 LOC: Config.onoff.log_udp
7378 If set, ICP queries are logged to access.log. You may wish
7379 do disable this if your ICP load is VERY high to speed things
7380 up or to simplify log analysis.
7383 NAME: udp_incoming_address
7385 LOC:Config.Addrs.udp_incoming
7387 DEFAULT_DOC: Accept packets from all machine interfaces.
7389 udp_incoming_address is used for UDP packets received from other
7392 The default behavior is to not bind to any specific address.
7394 Only change this if you want to have all UDP queries received on
7395 a specific interface/address.
7397 NOTE: udp_incoming_address is used by the ICP, HTCP, and DNS
7398 modules. Altering it will affect all of them in the same manner.
7400 see also; udp_outgoing_address
7402 NOTE, udp_incoming_address and udp_outgoing_address can not
7403 have the same value since they both use the same port.
7406 NAME: udp_outgoing_address
7408 LOC: Config.Addrs.udp_outgoing
7410 DEFAULT_DOC: Use udp_incoming_address or an address selected by the operating system.
7412 udp_outgoing_address is used for UDP packets sent out to other
7415 The default behavior is to not bind to any specific address.
7417 Instead it will use the same socket as udp_incoming_address.
7418 Only change this if you want to have UDP queries sent using another
7419 address than where this Squid listens for UDP queries from other
7422 NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS
7423 modules. Altering it will affect all of them in the same manner.
7425 see also; udp_incoming_address
7427 NOTE, udp_incoming_address and udp_outgoing_address can not
7428 have the same value since they both use the same port.
7435 LOC: Config.onoff.icp_hit_stale
7437 If you want to return ICP_HIT for stale cache objects, set this
7438 option to 'on'. If you have sibling relationships with caches
7439 in other administrative domains, this should be 'off'. If you only
7440 have sibling relationships with caches under your control,
7441 it is probably okay to set this to 'on'.
7442 If set to 'on', your siblings should use the option "allow-miss"
7443 on their cache_peer lines for connecting to you.
7446 NAME: minimum_direct_hops
7449 LOC: Config.minDirectHops
7451 If using the ICMP pinging stuff, do direct fetches for sites
7452 which are no more than this many hops away.
7455 NAME: minimum_direct_rtt
7459 LOC: Config.minDirectRtt
7461 If using the ICMP pinging stuff, do direct fetches for sites
7462 which are no more than this many rtt milliseconds away.
7468 LOC: Config.Netdb.low
7470 The low water mark for the ICMP measurement database.
7472 Note: high watermark controlled by netdb_high directive.
7474 These watermarks are counts, not percents. The defaults are
7475 (low) 900 and (high) 1000. When the high water mark is
7476 reached, database entries will be deleted until the low
7483 LOC: Config.Netdb.high
7485 The high water mark for the ICMP measurement database.
7487 Note: low watermark controlled by netdb_low directive.
7489 These watermarks are counts, not percents. The defaults are
7490 (low) 900 and (high) 1000. When the high water mark is
7491 reached, database entries will be deleted until the low
7495 NAME: netdb_ping_period
7497 LOC: Config.Netdb.period
7500 The minimum period for measuring a site. There will be at
7501 least this much delay between successive pings to the same
7502 network. The default is five minutes.
7509 LOC: Config.onoff.query_icmp
7511 If you want to ask your peers to include ICMP data in their ICP
7512 replies, enable this option.
7514 If your peer has configured Squid (during compilation) with
7515 '--enable-icmp' that peer will send ICMP pings to origin server
7516 sites of the URLs it receives. If you enable this option the
7517 ICP replies from that peer will include the ICMP data (if available).
7518 Then, when choosing a parent cache, Squid will choose the parent with
7519 the minimal RTT to the origin server. When this happens, the
7520 hierarchy field of the access.log will be
7521 "CLOSEST_PARENT_MISS". This option is off by default.
7524 NAME: test_reachability
7528 LOC: Config.onoff.test_reachability
7530 When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
7531 instead of ICP_MISS if the target host is NOT in the ICMP
7532 database, or has a zero RTT.
7535 NAME: icp_query_timeout
7538 DEFAULT_DOC: Dynamic detection.
7540 LOC: Config.Timeout.icp_query
7542 Normally Squid will automatically determine an optimal ICP
7543 query timeout value based on the round-trip-time of recent ICP
7544 queries. If you want to override the value determined by
7545 Squid, set this 'icp_query_timeout' to a non-zero value. This
7546 value is specified in MILLISECONDS, so, to use a 2-second
7547 timeout (the old default), you would write:
7549 icp_query_timeout 2000
7552 NAME: maximum_icp_query_timeout
7556 LOC: Config.Timeout.icp_query_max
7558 Normally the ICP query timeout is determined dynamically. But
7559 sometimes it can lead to very large values (say 5 seconds).
7560 Use this option to put an upper limit on the dynamic timeout
7561 value. Do NOT use this option to always use a fixed (instead
7562 of a dynamic) timeout value. To set a fixed timeout see the
7563 'icp_query_timeout' directive.
7566 NAME: minimum_icp_query_timeout
7570 LOC: Config.Timeout.icp_query_min
7572 Normally the ICP query timeout is determined dynamically. But
7573 sometimes it can lead to very small timeouts, even lower than
7574 the normal latency variance on your link due to traffic.
7575 Use this option to put an lower limit on the dynamic timeout
7576 value. Do NOT use this option to always use a fixed (instead
7577 of a dynamic) timeout value. To set a fixed timeout see the
7578 'icp_query_timeout' directive.
7581 NAME: background_ping_rate
7585 LOC: Config.backgroundPingRate
7587 Controls how often the ICP pings are sent to siblings that
7588 have background-ping set.
7592 MULTICAST ICP OPTIONS
7593 -----------------------------------------------------------------------------
7598 LOC: Config.mcast_group_list
7601 This tag specifies a list of multicast groups which your server
7602 should join to receive multicasted ICP queries.
7604 NOTE! Be very careful what you put here! Be sure you
7605 understand the difference between an ICP _query_ and an ICP
7606 _reply_. This option is to be set only if you want to RECEIVE
7607 multicast queries. Do NOT set this option to SEND multicast
7608 ICP (use cache_peer for that). ICP replies are always sent via
7609 unicast, so this option does not affect whether or not you will
7610 receive replies from multicast group members.
7612 You must be very careful to NOT use a multicast address which
7613 is already in use by another group of caches.
7615 If you are unsure about multicast, please read the Multicast
7616 chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
7618 Usage: mcast_groups 239.128.16.128 224.0.1.20
7620 By default, Squid doesn't listen on any multicast groups.
7623 NAME: mcast_miss_addr
7624 IFDEF: MULTICAST_MISS_STREAM
7626 LOC: Config.mcast_miss.addr
7628 DEFAULT_DOC: disabled.
7630 If you enable this option, every "cache miss" URL will
7631 be sent out on the specified multicast address.
7633 Do not enable this option unless you are are absolutely
7634 certain you understand what you are doing.
7637 NAME: mcast_miss_ttl
7638 IFDEF: MULTICAST_MISS_STREAM
7640 LOC: Config.mcast_miss.ttl
7643 This is the time-to-live value for packets multicasted
7644 when multicasting off cache miss URLs is enabled. By
7645 default this is set to 'site scope', i.e. 16.
7648 NAME: mcast_miss_port
7649 IFDEF: MULTICAST_MISS_STREAM
7651 LOC: Config.mcast_miss.port
7654 This is the port number to be used in conjunction with
7658 NAME: mcast_miss_encode_key
7659 IFDEF: MULTICAST_MISS_STREAM
7661 LOC: Config.mcast_miss.encode_key
7662 DEFAULT: XXXXXXXXXXXXXXXX
7664 The URLs that are sent in the multicast miss stream are
7665 encrypted. This is the encryption key.
7668 NAME: mcast_icp_query_timeout
7672 LOC: Config.Timeout.mcast_icp_query
7674 For multicast peers, Squid regularly sends out ICP "probes" to
7675 count how many other peers are listening on the given multicast
7676 address. This value specifies how long Squid should wait to
7677 count all the replies. The default is 2000 msec, or 2
7682 INTERNAL ICON OPTIONS
7683 -----------------------------------------------------------------------------
7686 NAME: icon_directory
7688 LOC: Config.icons.directory
7689 DEFAULT: @DEFAULT_ICON_DIR@
7691 Where the icons are stored. These are normally kept in
7695 NAME: global_internal_static
7697 LOC: Config.onoff.global_internal_static
7700 This directive controls is Squid should intercept all requests for
7701 /squid-internal-static/ no matter which host the URL is requesting
7702 (default on setting), or if nothing special should be done for
7703 such URLs (off setting). The purpose of this directive is to make
7704 icons etc work better in complex cache hierarchies where it may
7705 not always be possible for all corners in the cache mesh to reach
7706 the server generating a directory listing.
7709 NAME: short_icon_urls
7711 LOC: Config.icons.use_short_names
7714 If this is enabled Squid will use short URLs for icons.
7715 If disabled it will revert to the old behavior of including
7716 it's own name and port in the URL.
7718 If you run a complex cache hierarchy with a mix of Squid and
7719 other proxies you may need to disable this directive.
7724 -----------------------------------------------------------------------------
7727 NAME: error_directory
7729 LOC: Config.errorDirectory
7731 DEFAULT_DOC: Send error pages in the clients preferred language
7733 If you wish to create your own versions of the default
7734 error files to customize them to suit your company copy
7735 the error/template files to another directory and point
7738 WARNING: This option will disable multi-language support
7739 on error pages if used.
7741 The squid developers are interested in making squid available in
7742 a wide variety of languages. If you are making translations for a
7743 language that Squid does not currently provide please consider
7744 contributing your translation back to the project.
7745 http://wiki.squid-cache.org/Translations
7747 The squid developers working on translations are happy to supply drop-in
7748 translated error files in exchange for any new language contributions.
7751 NAME: error_default_language
7752 IFDEF: USE_ERR_LOCALES
7754 LOC: Config.errorDefaultLanguage
7756 DEFAULT_DOC: Generate English language pages.
7758 Set the default language which squid will send error pages in
7759 if no existing translation matches the clients language
7762 If unset (default) generic English will be used.
7764 The squid developers are interested in making squid available in
7765 a wide variety of languages. If you are interested in making
7766 translations for any language see the squid wiki for details.
7767 http://wiki.squid-cache.org/Translations
7770 NAME: error_log_languages
7771 IFDEF: USE_ERR_LOCALES
7773 LOC: Config.errorLogMissingLanguages
7776 Log to cache.log what languages users are attempting to
7777 auto-negotiate for translations.
7779 Successful negotiations are not logged. Only failures
7780 have meaning to indicate that Squid may need an upgrade
7781 of its error page translations.
7784 NAME: err_page_stylesheet
7786 LOC: Config.errorStylesheet
7787 DEFAULT: @DEFAULT_CONFIG_DIR@/errorpage.css
7789 CSS Stylesheet to pattern the display of Squid default error pages.
7791 For information on CSS see http://www.w3.org/Style/CSS/
7796 LOC: Config.errHtmlText
7799 HTML text to include in error messages. Make this a "mailto"
7800 URL to your admin address, or maybe just a link to your
7801 organizations Web page.
7803 To include this in your error messages, you must rewrite
7804 the error template files (found in the "errors" directory).
7805 Wherever you want the 'err_html_text' line to appear,
7806 insert a %L tag in the error template file.
7809 NAME: email_err_data
7812 LOC: Config.onoff.emailErrData
7815 If enabled, information about the occurred error will be
7816 included in the mailto links of the ERR pages (if %W is set)
7817 so that the email body contains the data.
7818 Syntax is <A HREF="mailto:%w%W">%w</A>
7823 LOC: Config.denyInfoList
7826 Usage: deny_info err_page_name acl
7827 or deny_info http://... acl
7828 or deny_info TCP_RESET acl
7830 This can be used to return a ERR_ page for requests which
7831 do not pass the 'http_access' rules. Squid remembers the last
7832 acl it evaluated in http_access, and if a 'deny_info' line exists
7833 for that ACL Squid returns a corresponding error page.
7835 The acl is typically the last acl on the http_access deny line which
7836 denied access. The exceptions to this rule are:
7837 - When Squid needs to request authentication credentials. It's then
7838 the first authentication related acl encountered
7839 - When none of the http_access lines matches. It's then the last
7840 acl processed on the last http_access line.
7841 - When the decision to deny access was made by an adaptation service,
7842 the acl name is the corresponding eCAP or ICAP service_name.
7844 NP: If providing your own custom error pages with error_directory
7845 you may also specify them by your custom file name:
7846 Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
7848 By defaut Squid will send "403 Forbidden". A different 4xx or 5xx
7849 may be specified by prefixing the file name with the code and a colon.
7850 e.g. 404:ERR_CUSTOM_ACCESS_DENIED
7852 Alternatively you can tell Squid to reset the TCP connection
7853 by specifying TCP_RESET.
7855 Or you can specify an error URL or URL pattern. The browsers will
7856 get redirected to the specified URL after formatting tags have
7857 been replaced. Redirect will be done with 302 or 307 according to
7858 HTTP/1.1 specs. A different 3xx code may be specified by prefixing
7859 the URL. e.g. 303:http://example.com/
7862 %a - username (if available. Password NOT included)
7865 %E - Error description
7867 %H - Request domain name
7868 %i - Client IP Address
7870 %o - Message result from external ACL helper
7871 %p - Request Port number
7872 %P - Request Protocol name
7873 %R - Request URL path
7874 %T - Timestamp in RFC 1123 format
7875 %U - Full canonical URL from client
7876 (HTTPS URLs terminate with *)
7877 %u - Full canonical URL from client
7878 %w - Admin email from squid.conf
7880 %% - Literal percent (%) code
7885 OPTIONS INFLUENCING REQUEST FORWARDING
7886 -----------------------------------------------------------------------------
7889 NAME: nonhierarchical_direct
7891 LOC: Config.onoff.nonhierarchical_direct
7894 By default, Squid will send any non-hierarchical requests
7895 (not cacheable request type) direct to origin servers.
7897 When this is set to "off", Squid will prefer to send these
7898 requests to parents.
7900 Note that in most configurations, by turning this off you will only
7901 add latency to these request without any improvement in global hit
7904 This option only sets a preference. If the parent is unavailable a
7905 direct connection to the origin server may still be attempted. To
7906 completely prevent direct connections use never_direct.
7911 LOC: Config.onoff.prefer_direct
7914 Normally Squid tries to use parents for most requests. If you for some
7915 reason like it to first try going direct and only use a parent if
7916 going direct fails set this to on.
7918 By combining nonhierarchical_direct off and prefer_direct on you
7919 can set up Squid to use a parent as a backup path if going direct
7922 Note: If you want Squid to use parents for all requests see
7923 the never_direct directive. prefer_direct only modifies how Squid
7924 acts on cacheable requests.
7927 NAME: cache_miss_revalidate
7931 LOC: Config.onoff.cache_miss_revalidate
7933 RFC 7232 defines a conditional request mechanism to prevent
7934 response objects being unnecessarily transferred over the network.
7935 If that mechanism is used by the client and a cache MISS occurs
7936 it can prevent new cache entries being created.
7938 This option determines whether Squid on cache MISS will pass the
7939 client revalidation request to the server or tries to fetch new
7940 content for caching. It can be useful while the cache is mostly
7941 empty to more quickly have the cache populated by generating
7942 non-conditional GETs.
7944 When set to 'on' (default), Squid will pass all client If-* headers
7945 to the server. This permits server responses without a cacheable
7946 payload to be delivered and on MISS no new cache entry is created.
7948 When set to 'off' and if the request is cacheable, Squid will
7949 remove the clients If-Modified-Since and If-None-Match headers from
7950 the request sent to the server. This requests a 200 status response
7951 from the server to create a new cache entry with.
7956 LOC: Config.accessList.AlwaysDirect
7958 DEFAULT_DOC: Prevent any cache_peer being used for this request.
7960 Usage: always_direct allow|deny [!]aclname ...
7962 Here you can use ACL elements to specify requests which should
7963 ALWAYS be forwarded by Squid to the origin servers without using
7964 any peers. For example, to always directly forward requests for
7965 local servers ignoring any parents or siblings you may have use
7968 acl local-servers dstdomain my.domain.net
7969 always_direct allow local-servers
7971 To always forward FTP requests directly, use
7974 always_direct allow FTP
7976 NOTE: There is a similar, but opposite option named
7977 'never_direct'. You need to be aware that "always_direct deny
7978 foo" is NOT the same thing as "never_direct allow foo". You
7979 may need to use a deny rule to exclude a more-specific case of
7980 some other rule. Example:
7982 acl local-external dstdomain external.foo.net
7983 acl local-servers dstdomain .foo.net
7984 always_direct deny local-external
7985 always_direct allow local-servers
7987 NOTE: If your goal is to make the client forward the request
7988 directly to the origin server bypassing Squid then this needs
7989 to be done in the client configuration. Squid configuration
7990 can only tell Squid how Squid should fetch the object.
7992 NOTE: This directive is not related to caching. The replies
7993 is cached as usual even if you use always_direct. To not cache
7994 the replies see the 'cache' directive.
7996 This clause supports both fast and slow acl types.
7997 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
8002 LOC: Config.accessList.NeverDirect
8004 DEFAULT_DOC: Allow DNS results to be used for this request.
8006 Usage: never_direct allow|deny [!]aclname ...
8008 never_direct is the opposite of always_direct. Please read
8009 the description for always_direct if you have not already.
8011 With 'never_direct' you can use ACL elements to specify
8012 requests which should NEVER be forwarded directly to origin
8013 servers. For example, to force the use of a proxy for all
8014 requests, except those in your local domain use something like:
8016 acl local-servers dstdomain .foo.net
8017 never_direct deny local-servers
8018 never_direct allow all
8020 or if Squid is inside a firewall and there are local intranet
8021 servers inside the firewall use something like:
8023 acl local-intranet dstdomain .foo.net
8024 acl local-external dstdomain external.foo.net
8025 always_direct deny local-external
8026 always_direct allow local-intranet
8027 never_direct allow all
8029 This clause supports both fast and slow acl types.
8030 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
8034 ADVANCED NETWORKING OPTIONS
8035 -----------------------------------------------------------------------------
8038 NAME: incoming_udp_average incoming_icp_average
8041 LOC: Config.comm_incoming.udp.average
8043 Heavy voodoo here. I can't even believe you are reading this.
8044 Are you crazy? Don't even think about adjusting these unless
8045 you understand the algorithms in comm_select.c first!
8048 NAME: incoming_tcp_average incoming_http_average
8051 LOC: Config.comm_incoming.tcp.average
8053 Heavy voodoo here. I can't even believe you are reading this.
8054 Are you crazy? Don't even think about adjusting these unless
8055 you understand the algorithms in comm_select.c first!
8058 NAME: incoming_dns_average
8061 LOC: Config.comm_incoming.dns.average
8063 Heavy voodoo here. I can't even believe you are reading this.
8064 Are you crazy? Don't even think about adjusting these unless
8065 you understand the algorithms in comm_select.c first!
8068 NAME: min_udp_poll_cnt min_icp_poll_cnt
8071 LOC: Config.comm_incoming.udp.min_poll
8073 Heavy voodoo here. I can't even believe you are reading this.
8074 Are you crazy? Don't even think about adjusting these unless
8075 you understand the algorithms in comm_select.c first!
8078 NAME: min_dns_poll_cnt
8081 LOC: Config.comm_incoming.dns.min_poll
8083 Heavy voodoo here. I can't even believe you are reading this.
8084 Are you crazy? Don't even think about adjusting these unless
8085 you understand the algorithms in comm_select.c first!
8088 NAME: min_tcp_poll_cnt min_http_poll_cnt
8091 LOC: Config.comm_incoming.tcp.min_poll
8093 Heavy voodoo here. I can't even believe you are reading this.
8094 Are you crazy? Don't even think about adjusting these unless
8095 you understand the algorithms in comm_select.c first!
8101 LOC: Config.accept_filter
8105 The name of an accept(2) filter to install on Squid's
8106 listen socket(s). This feature is perhaps specific to
8107 FreeBSD and requires support in the kernel.
8109 The 'httpready' filter delays delivering new connections
8110 to Squid until a full HTTP request has been received.
8111 See the accf_http(9) man page for details.
8113 The 'dataready' filter delays delivering new connections
8114 to Squid until there is some data to process.
8115 See the accf_dataready(9) man page for details.
8119 The 'data' filter delays delivering of new connections
8120 to Squid until there is some data to process by TCP_ACCEPT_DEFER.
8121 You may optionally specify a number of seconds to wait by
8122 'data=N' where N is the number of seconds. Defaults to 30
8123 if not specified. See the tcp(7) man page for details.
8126 accept_filter httpready
8131 NAME: client_ip_max_connections
8133 LOC: Config.client_ip_max_connections
8135 DEFAULT_DOC: No limit.
8137 Set an absolute limit on the number of connections a single
8138 client IP can use. Any more than this and Squid will begin to drop
8139 new connections from the client until it closes some links.
8141 Note that this is a global limit. It affects all HTTP, HTCP, Gopher and FTP
8142 connections from the client. For finer control use the ACL access controls.
8144 Requires client_db to be enabled (the default).
8146 WARNING: This may noticably slow down traffic received via external proxies
8147 or NAT devices and cause them to rebound error messages back to their clients.
8150 NAME: tcp_recv_bufsize
8154 DEFAULT_DOC: Use operating system TCP defaults.
8155 LOC: Config.tcpRcvBufsz
8157 Size of receive buffer to set for TCP sockets. Probably just
8158 as easy to change your kernel's default.
8159 Omit from squid.conf to use the default buffer size.
8164 -----------------------------------------------------------------------------
8171 LOC: Adaptation::Icap::TheConfig.onoff
8174 If you want to enable the ICAP module support, set this to on.
8177 NAME: icap_connect_timeout
8180 LOC: Adaptation::Icap::TheConfig.connect_timeout_raw
8183 This parameter specifies how long to wait for the TCP connect to
8184 the requested ICAP server to complete before giving up and either
8185 terminating the HTTP transaction or bypassing the failure.
8187 The default for optional services is peer_connect_timeout.
8188 The default for essential services is connect_timeout.
8189 If this option is explicitly set, its value applies to all services.
8192 NAME: icap_io_timeout
8196 DEFAULT_DOC: Use read_timeout.
8197 LOC: Adaptation::Icap::TheConfig.io_timeout_raw
8200 This parameter specifies how long to wait for an I/O activity on
8201 an established, active ICAP connection before giving up and
8202 either terminating the HTTP transaction or bypassing the
8206 NAME: icap_service_failure_limit
8207 COMMENT: limit [in memory-depth time-units]
8208 TYPE: icap_service_failure_limit
8210 LOC: Adaptation::Icap::TheConfig
8213 The limit specifies the number of failures that Squid tolerates
8214 when establishing a new TCP connection with an ICAP service. If
8215 the number of failures exceeds the limit, the ICAP service is
8216 not used for new ICAP requests until it is time to refresh its
8219 A negative value disables the limit. Without the limit, an ICAP
8220 service will not be considered down due to connectivity failures
8221 between ICAP OPTIONS requests.
8223 Squid forgets ICAP service failures older than the specified
8224 value of memory-depth. The memory fading algorithm
8225 is approximate because Squid does not remember individual
8226 errors but groups them instead, splitting the option
8227 value into ten time slots of equal length.
8229 When memory-depth is 0 and by default this option has no
8230 effect on service failure expiration.
8232 Squid always forgets failures when updating service settings
8233 using an ICAP OPTIONS transaction, regardless of this option
8237 # suspend service usage after 10 failures in 5 seconds:
8238 icap_service_failure_limit 10 in 5 seconds
8241 NAME: icap_service_revival_delay
8244 LOC: Adaptation::Icap::TheConfig.service_revival_delay
8247 The delay specifies the number of seconds to wait after an ICAP
8248 OPTIONS request failure before requesting the options again. The
8249 failed ICAP service is considered "down" until fresh OPTIONS are
8252 The actual delay cannot be smaller than the hardcoded minimum
8253 delay of 30 seconds.
8256 NAME: icap_preview_enable
8260 LOC: Adaptation::Icap::TheConfig.preview_enable
8263 The ICAP Preview feature allows the ICAP server to handle the
8264 HTTP message by looking only at the beginning of the message body
8265 or even without receiving the body at all. In some environments,
8266 previews greatly speedup ICAP processing.
8268 During an ICAP OPTIONS transaction, the server may tell Squid what
8269 HTTP messages should be previewed and how big the preview should be.
8270 Squid will not use Preview if the server did not request one.
8272 To disable ICAP Preview for all ICAP services, regardless of
8273 individual ICAP server OPTIONS responses, set this option to "off".
8275 icap_preview_enable off
8278 NAME: icap_preview_size
8281 LOC: Adaptation::Icap::TheConfig.preview_size
8283 DEFAULT_DOC: No preview sent.
8285 The default size of preview data to be sent to the ICAP server.
8286 This value might be overwritten on a per server basis by OPTIONS requests.
8289 NAME: icap_206_enable
8293 LOC: Adaptation::Icap::TheConfig.allow206_enable
8296 206 (Partial Content) responses is an ICAP extension that allows the
8297 ICAP agents to optionally combine adapted and original HTTP message
8298 content. The decision to combine is postponed until the end of the
8299 ICAP response. Squid supports Partial Content extension by default.
8301 Activation of the Partial Content extension is negotiated with each
8302 ICAP service during OPTIONS exchange. Most ICAP servers should handle
8303 negotation correctly even if they do not support the extension, but
8304 some might fail. To disable Partial Content support for all ICAP
8305 services and to avoid any negotiation, set this option to "off".
8311 NAME: icap_default_options_ttl
8314 LOC: Adaptation::Icap::TheConfig.default_options_ttl
8317 The default TTL value for ICAP OPTIONS responses that don't have
8318 an Options-TTL header.
8321 NAME: icap_persistent_connections
8325 LOC: Adaptation::Icap::TheConfig.reuse_connections
8328 Whether or not Squid should use persistent connections to
8332 NAME: adaptation_send_client_ip icap_send_client_ip
8334 IFDEF: USE_ADAPTATION
8336 LOC: Adaptation::Config::send_client_ip
8339 If enabled, Squid shares HTTP client IP information with adaptation
8340 services. For ICAP, Squid adds the X-Client-IP header to ICAP requests.
8341 For eCAP, Squid sets the libecap::metaClientIp transaction option.
8343 See also: adaptation_uses_indirect_client
8346 NAME: adaptation_send_username icap_send_client_username
8348 IFDEF: USE_ADAPTATION
8350 LOC: Adaptation::Config::send_username
8353 This sends authenticated HTTP client username (if available) to
8354 the adaptation service.
8356 For ICAP, the username value is encoded based on the
8357 icap_client_username_encode option and is sent using the header
8358 specified by the icap_client_username_header option.
8361 NAME: icap_client_username_header
8364 LOC: Adaptation::Icap::TheConfig.client_username_header
8365 DEFAULT: X-Client-Username
8367 ICAP request header name to use for adaptation_send_username.
8370 NAME: icap_client_username_encode
8374 LOC: Adaptation::Icap::TheConfig.client_username_encode
8377 Whether to base64 encode the authenticated client username.
8381 TYPE: icap_service_type
8383 LOC: Adaptation::Icap::TheConfig
8386 Defines a single ICAP service using the following format:
8388 icap_service id vectoring_point uri [option ...]
8391 an opaque identifier or name which is used to direct traffic to
8392 this specific service. Must be unique among all adaptation
8393 services in squid.conf.
8395 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
8396 This specifies at which point of transaction processing the
8397 ICAP service should be activated. *_postcache vectoring points
8398 are not yet supported.
8400 uri: icap://servername:port/servicepath
8401 ICAP server and service location.
8402 icaps://servername:port/servicepath
8403 The "icap:" URI scheme is used for traditional ICAP server and
8404 service location (default port is 1344, connections are not
8405 encrypted). The "icaps:" URI scheme is for Secure ICAP
8406 services that use SSL/TLS-encrypted ICAP connections (by
8407 default, on port 11344).
8409 ICAP does not allow a single service to handle both REQMOD and RESPMOD
8410 transactions. Squid does not enforce that requirement. You can specify
8411 services with the same service_url and different vectoring_points. You
8412 can even specify multiple identical services as long as their
8413 service_names differ.
8415 To activate a service, use the adaptation_access directive. To group
8416 services, use adaptation_service_chain and adaptation_service_set.
8418 Service options are separated by white space. ICAP services support
8419 the following name=value options:
8422 If set to 'on' or '1', the ICAP service is treated as
8423 optional. If the service cannot be reached or malfunctions,
8424 Squid will try to ignore any errors and process the message as
8425 if the service was not enabled. No all ICAP errors can be
8426 bypassed. If set to 0, the ICAP service is treated as
8427 essential and all ICAP errors will result in an error page
8428 returned to the HTTP client.
8430 Bypass is off by default: services are treated as essential.
8433 If set to 'on' or '1', the ICAP service is allowed to
8434 dynamically change the current message adaptation plan by
8435 returning a chain of services to be used next. The services
8436 are specified using the X-Next-Services ICAP response header
8437 value, formatted as a comma-separated list of service names.
8438 Each named service should be configured in squid.conf. Other
8439 services are ignored. An empty X-Next-Services value results
8440 in an empty plan which ends the current adaptation.
8442 Dynamic adaptation plan may cross or cover multiple supported
8443 vectoring points in their natural processing order.
8445 Routing is not allowed by default: the ICAP X-Next-Services
8446 response header is ignored.
8449 Only has effect on split-stack systems. The default on those systems
8450 is to use IPv4-only connections. When set to 'on' this option will
8451 make Squid use IPv6-only connections to contact this ICAP service.
8453 on-overload=block|bypass|wait|force
8454 If the service Max-Connections limit has been reached, do
8455 one of the following for each new ICAP transaction:
8456 * block: send an HTTP error response to the client
8457 * bypass: ignore the "over-connected" ICAP service
8458 * wait: wait (in a FIFO queue) for an ICAP connection slot
8459 * force: proceed, ignoring the Max-Connections limit
8461 In SMP mode with N workers, each worker assumes the service
8462 connection limit is Max-Connections/N, even though not all
8463 workers may use a given service.
8465 The default value is "bypass" if service is bypassable,
8466 otherwise it is set to "wait".
8470 Use the given number as the Max-Connections limit, regardless
8471 of the Max-Connections value given by the service, if any.
8473 ==== ICAPS / TLS OPTIONS ====
8475 These options are used for Secure ICAP (icaps://....) services only.
8477 tls-cert=/path/to/ssl/certificate
8478 A client SSL certificate to use when connecting to
8481 tls-key=/path/to/ssl/key
8482 The private TLS/SSL key corresponding to sslcert above.
8483 If 'tls-key' is not specified 'tls-cert' is assumed to
8484 reference a combined PEM format file containing both the
8485 certificate and the key.
8487 tls-cipher=... The list of valid TLS/SSL ciphers to use when connecting
8488 to this icap server.
8491 The minimum TLS protocol version to permit. To control
8492 SSLv3 use the ssloptions= parameter.
8493 Supported Values: 1.0 (default), 1.1, 1.2
8495 tls-options=... Specify various OpenSSL library options:
8497 NO_SSLv3 Disallow the use of SSLv3
8499 NO_TLSv1 Disallow the use of TLSv1.0
8500 NO_TLSv1_1 Disallow the use of TLSv1.1
8501 NO_TLSv1_2 Disallow the use of TLSv1.2
8504 Always create a new key when using
8505 temporary/ephemeral DH key exchanges
8507 ALL Enable various bug workarounds
8508 suggested as "harmless" by OpenSSL
8509 Be warned that this reduces SSL/TLS
8510 strength to some attacks.
8512 See the OpenSSL SSL_CTX_set_options documentation for a
8513 more complete list. Options relevant only to SSLv2 are
8516 tls-cafile=... A PEM file containing additional CA certificates to use
8517 when verifying the icap server certificate. Used
8518 to specify intermediate CA certificate(s) if not sent
8519 by the server. Or the full CA chain for the server
8520 when using the NO_DEFAULT_CA flag.
8522 tls-capath=... A directory containing additional CA certificates to
8523 use when verifying the icap server certificate.
8525 tls-crlfile=... A certificate revocation list file to use when
8526 verifying the icap server certificate.
8528 tls-flags=... Specify various flags modifying the Squid TLS implementation:
8531 Accept certificates even if they fail to
8534 Don't use the default CA list built into
8537 Don't verify the icap server certificate
8538 matches the server name
8540 tls-domain= The icap server name as advertised in it's certificate.
8541 Used for verifying the correctness of the received icap
8542 server certificate. If not specified the icap server
8543 hostname extracted from ICAP URI will be used.
8545 Older icap_service format without optional named parameters is
8546 deprecated but supported for backward compatibility.
8549 icap_service svcBlocker reqmod_precache icap://icap1.mydomain.net:1344/reqmod bypass=0
8550 icap_service svcLogger reqmod_precache icaps://icap2.mydomain.net:11344/reqmod routing=on
8554 TYPE: icap_class_type
8559 This deprecated option was documented to define an ICAP service
8560 chain, even though it actually defined a set of similar, redundant
8561 services, and the chains were not supported.
8563 To define a set of redundant services, please use the
8564 adaptation_service_set directive. For service chains, use
8565 adaptation_service_chain.
8569 TYPE: icap_access_type
8574 This option is deprecated. Please use adaptation_access, which
8575 has the same ICAP functionality, but comes with better
8576 documentation, and eCAP support.
8581 -----------------------------------------------------------------------------
8588 LOC: Adaptation::Ecap::TheConfig.onoff
8591 Controls whether eCAP support is enabled.
8595 TYPE: ecap_service_type
8597 LOC: Adaptation::Ecap::TheConfig
8600 Defines a single eCAP service
8602 ecap_service id vectoring_point uri [option ...]
8605 an opaque identifier or name which is used to direct traffic to
8606 this specific service. Must be unique among all adaptation
8607 services in squid.conf.
8609 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
8610 This specifies at which point of transaction processing the
8611 eCAP service should be activated. *_postcache vectoring points
8612 are not yet supported.
8614 uri: ecap://vendor/service_name?custom&cgi=style¶meters=optional
8615 Squid uses the eCAP service URI to match this configuration
8616 line with one of the dynamically loaded services. Each loaded
8617 eCAP service must have a unique URI. Obtain the right URI from
8618 the service provider.
8620 To activate a service, use the adaptation_access directive. To group
8621 services, use adaptation_service_chain and adaptation_service_set.
8623 Service options are separated by white space. eCAP services support
8624 the following name=value options:
8627 If set to 'on' or '1', the eCAP service is treated as optional.
8628 If the service cannot be reached or malfunctions, Squid will try
8629 to ignore any errors and process the message as if the service
8630 was not enabled. No all eCAP errors can be bypassed.
8631 If set to 'off' or '0', the eCAP service is treated as essential
8632 and all eCAP errors will result in an error page returned to the
8635 Bypass is off by default: services are treated as essential.
8638 If set to 'on' or '1', the eCAP service is allowed to
8639 dynamically change the current message adaptation plan by
8640 returning a chain of services to be used next.
8642 Dynamic adaptation plan may cross or cover multiple supported
8643 vectoring points in their natural processing order.
8645 Routing is not allowed by default.
8647 Older ecap_service format without optional named parameters is
8648 deprecated but supported for backward compatibility.
8652 ecap_service s1 reqmod_precache ecap://filters.R.us/leakDetector?on_error=block bypass=off
8653 ecap_service s2 respmod_precache ecap://filters.R.us/virusFilter config=/etc/vf.cfg bypass=on
8656 NAME: loadable_modules
8658 IFDEF: USE_LOADABLE_MODULES
8659 LOC: Config.loadable_module_names
8662 Instructs Squid to load the specified dynamic module(s) or activate
8663 preloaded module(s).
8665 loadable_modules @DEFAULT_PREFIX@/lib/MinimalAdapter.so
8669 MESSAGE ADAPTATION OPTIONS
8670 -----------------------------------------------------------------------------
8673 NAME: adaptation_service_set
8674 TYPE: adaptation_service_set_type
8675 IFDEF: USE_ADAPTATION
8680 Configures an ordered set of similar, redundant services. This is
8681 useful when hot standby or backup adaptation servers are available.
8683 adaptation_service_set set_name service_name1 service_name2 ...
8685 The named services are used in the set declaration order. The first
8686 applicable adaptation service from the set is used first. The next
8687 applicable service is tried if and only if the transaction with the
8688 previous service fails and the message waiting to be adapted is still
8691 When adaptation starts, broken services are ignored as if they were
8692 not a part of the set. A broken service is a down optional service.
8694 The services in a set must be attached to the same vectoring point
8695 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
8697 If all services in a set are optional then adaptation failures are
8698 bypassable. If all services in the set are essential, then a
8699 transaction failure with one service may still be retried using
8700 another service from the set, but when all services fail, the master
8701 transaction fails as well.
8703 A set may contain a mix of optional and essential services, but that
8704 is likely to lead to surprising results because broken services become
8705 ignored (see above), making previously bypassable failures fatal.
8706 Technically, it is the bypassability of the last failed service that
8709 See also: adaptation_access adaptation_service_chain
8712 adaptation_service_set svcBlocker urlFilterPrimary urlFilterBackup
8713 adaptation service_set svcLogger loggerLocal loggerRemote
8716 NAME: adaptation_service_chain
8717 TYPE: adaptation_service_chain_type
8718 IFDEF: USE_ADAPTATION
8723 Configures a list of complementary services that will be applied
8724 one-by-one, forming an adaptation chain or pipeline. This is useful
8725 when Squid must perform different adaptations on the same message.
8727 adaptation_service_chain chain_name service_name1 svc_name2 ...
8729 The named services are used in the chain declaration order. The first
8730 applicable adaptation service from the chain is used first. The next
8731 applicable service is applied to the successful adaptation results of
8732 the previous service in the chain.
8734 When adaptation starts, broken services are ignored as if they were
8735 not a part of the chain. A broken service is a down optional service.
8737 Request satisfaction terminates the adaptation chain because Squid
8738 does not currently allow declaration of RESPMOD services at the
8739 "reqmod_precache" vectoring point (see icap_service or ecap_service).
8741 The services in a chain must be attached to the same vectoring point
8742 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
8744 A chain may contain a mix of optional and essential services. If an
8745 essential adaptation fails (or the failure cannot be bypassed for
8746 other reasons), the master transaction fails. Otherwise, the failure
8747 is bypassed as if the failed adaptation service was not in the chain.
8749 See also: adaptation_access adaptation_service_set
8752 adaptation_service_chain svcRequest requestLogger urlFilter leakDetector
8755 NAME: adaptation_access
8756 TYPE: adaptation_access_type
8757 IFDEF: USE_ADAPTATION
8760 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
8762 Sends an HTTP transaction to an ICAP or eCAP adaptation service.
8764 adaptation_access service_name allow|deny [!]aclname...
8765 adaptation_access set_name allow|deny [!]aclname...
8767 At each supported vectoring point, the adaptation_access
8768 statements are processed in the order they appear in this
8769 configuration file. Statements pointing to the following services
8770 are ignored (i.e., skipped without checking their ACL):
8772 - services serving different vectoring points
8773 - "broken-but-bypassable" services
8774 - "up" services configured to ignore such transactions
8775 (e.g., based on the ICAP Transfer-Ignore header).
8777 When a set_name is used, all services in the set are checked
8778 using the same rules, to find the first applicable one. See
8779 adaptation_service_set for details.
8781 If an access list is checked and there is a match, the
8782 processing stops: For an "allow" rule, the corresponding
8783 adaptation service is used for the transaction. For a "deny"
8784 rule, no adaptation service is activated.
8786 It is currently not possible to apply more than one adaptation
8787 service at the same vectoring point to the same HTTP transaction.
8789 See also: icap_service and ecap_service
8792 adaptation_access service_1 allow all
8795 NAME: adaptation_service_iteration_limit
8797 IFDEF: USE_ADAPTATION
8798 LOC: Adaptation::Config::service_iteration_limit
8801 Limits the number of iterations allowed when applying adaptation
8802 services to a message. If your longest adaptation set or chain
8803 may have more than 16 services, increase the limit beyond its
8804 default value of 16. If detecting infinite iteration loops sooner
8805 is critical, make the iteration limit match the actual number
8806 of services in your longest adaptation set or chain.
8808 Infinite adaptation loops are most likely with routing services.
8810 See also: icap_service routing=1
8813 NAME: adaptation_masterx_shared_names
8815 IFDEF: USE_ADAPTATION
8816 LOC: Adaptation::Config::masterx_shared_name
8819 For each master transaction (i.e., the HTTP request and response
8820 sequence, including all related ICAP and eCAP exchanges), Squid
8821 maintains a table of metadata. The table entries are (name, value)
8822 pairs shared among eCAP and ICAP exchanges. The table is destroyed
8823 with the master transaction.
8825 This option specifies the table entry names that Squid must accept
8826 from and forward to the adaptation transactions.
8828 An ICAP REQMOD or RESPMOD transaction may set an entry in the
8829 shared table by returning an ICAP header field with a name
8830 specified in adaptation_masterx_shared_names.
8832 An eCAP REQMOD or RESPMOD transaction may set an entry in the
8833 shared table by implementing the libecap::visitEachOption() API
8834 to provide an option with a name specified in
8835 adaptation_masterx_shared_names.
8837 Squid will store and forward the set entry to subsequent adaptation
8838 transactions within the same master transaction scope.
8840 Only one shared entry name is supported at this time.
8843 # share authentication information among ICAP services
8844 adaptation_masterx_shared_names X-Subscriber-ID
8847 NAME: adaptation_meta
8849 IFDEF: USE_ADAPTATION
8850 LOC: Adaptation::Config::metaHeaders
8853 This option allows Squid administrator to add custom ICAP request
8854 headers or eCAP options to Squid ICAP requests or eCAP transactions.
8855 Use it to pass custom authentication tokens and other
8856 transaction-state related meta information to an ICAP/eCAP service.
8858 The addition of a meta header is ACL-driven:
8859 adaptation_meta name value [!]aclname ...
8861 Processing for a given header name stops after the first ACL list match.
8862 Thus, it is impossible to add two headers with the same name. If no ACL
8863 lists match for a given header name, no such header is added. For
8866 # do not debug transactions except for those that need debugging
8867 adaptation_meta X-Debug 1 needs_debugging
8869 # log all transactions except for those that must remain secret
8870 adaptation_meta X-Log 1 !keep_secret
8872 # mark transactions from users in the "G 1" group
8873 adaptation_meta X-Authenticated-Groups "G 1" authed_as_G1
8875 The "value" parameter may be a regular squid.conf token or a "double
8876 quoted string". Within the quoted string, use backslash (\) to escape
8877 any character, which is currently only useful for escaping backslashes
8878 and double quotes. For example,
8879 "this string has one backslash (\\) and two \"quotes\""
8881 Used adaptation_meta header values may be logged via %note
8882 logformat code. If multiple adaptation_meta headers with the same name
8883 are used during master transaction lifetime, the header values are
8884 logged in the order they were used and duplicate values are ignored
8885 (only the first repeated value will be logged).
8891 LOC: Adaptation::Icap::TheConfig.repeat
8892 DEFAULT_IF_NONE: deny all
8894 This ACL determines which retriable ICAP transactions are
8895 retried. Transactions that received a complete ICAP response
8896 and did not have to consume or produce HTTP bodies to receive
8897 that response are usually retriable.
8899 icap_retry allow|deny [!]aclname ...
8901 Squid automatically retries some ICAP I/O timeouts and errors
8902 due to persistent connection race conditions.
8904 See also: icap_retry_limit
8907 NAME: icap_retry_limit
8910 LOC: Adaptation::Icap::TheConfig.repeat_limit
8912 DEFAULT_DOC: No retries are allowed.
8914 Limits the number of retries allowed.
8916 Communication errors due to persistent connection race
8917 conditions are unavoidable, automatically retried, and do not
8918 count against this limit.
8920 See also: icap_retry
8926 -----------------------------------------------------------------------------
8929 NAME: check_hostnames
8932 LOC: Config.onoff.check_hostnames
8934 For security and stability reasons Squid can check
8935 hostnames for Internet standard RFC compliance. If you want
8936 Squid to perform these checks turn this directive on.
8939 NAME: allow_underscore
8942 LOC: Config.onoff.allow_underscore
8944 Underscore characters is not strictly allowed in Internet hostnames
8945 but nevertheless used by many sites. Set this to off if you want
8946 Squid to be strict about the standard.
8947 This check is performed only when check_hostnames is set to on.
8950 NAME: dns_retransmit_interval
8953 LOC: Config.Timeout.idns_retransmit
8955 Initial retransmit interval for DNS queries. The interval is
8956 doubled each time all configured DNS servers have been tried.
8962 LOC: Config.Timeout.idns_query
8964 DNS Query timeout. If no response is received to a DNS query
8965 within this time all DNS servers for the queried domain
8966 are assumed to be unavailable.
8969 NAME: dns_packet_max
8971 DEFAULT_DOC: EDNS disabled
8973 LOC: Config.dns.packet_max
8975 Maximum number of bytes packet size to advertise via EDNS.
8976 Set to "none" to disable EDNS large packet support.
8978 For legacy reasons DNS UDP replies will default to 512 bytes which
8979 is too small for many responses. EDNS provides a means for Squid to
8980 negotiate receiving larger responses back immediately without having
8981 to failover with repeat requests. Responses larger than this limit
8982 will retain the old behaviour of failover to TCP DNS.
8984 Squid has no real fixed limit internally, but allowing packet sizes
8985 over 1500 bytes requires network jumbogram support and is usually not
8988 WARNING: The RFC also indicates that some older resolvers will reply
8989 with failure of the whole request if the extension is added. Some
8990 resolvers have already been identified which will reply with mangled
8991 EDNS response on occasion. Usually in response to many-KB jumbogram
8992 sizes being advertised by Squid.
8993 Squid will currently treat these both as an unable-to-resolve domain
8994 even if it would be resolvable without EDNS.
9001 DEFAULT_DOC: Search for single-label domain names is disabled.
9002 LOC: Config.onoff.res_defnames
9004 Normally the RES_DEFNAMES resolver option is disabled
9005 (see res_init(3)). This prevents caches in a hierarchy
9006 from interpreting single-component hostnames locally. To allow
9007 Squid to handle single-component names, enable this option.
9010 NAME: dns_multicast_local
9014 DEFAULT_DOC: Search for .local and .arpa names is disabled.
9015 LOC: Config.onoff.dns_mdns
9017 When set to on, Squid sends multicast DNS lookups on the local
9018 network for domains ending in .local and .arpa.
9019 This enables local servers and devices to be contacted in an
9020 ad-hoc or zero-configuration network environment.
9023 NAME: dns_nameservers
9026 DEFAULT_DOC: Use operating system definitions
9027 LOC: Config.dns_nameservers
9029 Use this if you want to specify a list of DNS name servers
9030 (IP addresses) to use instead of those given in your
9031 /etc/resolv.conf file.
9033 On Windows platforms, if no value is specified here or in
9034 the /etc/resolv.conf file, the list of DNS name servers are
9035 taken from the Windows registry, both static and dynamic DHCP
9036 configurations are supported.
9038 Example: dns_nameservers 10.0.0.1 192.172.0.4
9043 DEFAULT: @DEFAULT_HOSTS@
9044 LOC: Config.etcHostsPath
9046 Location of the host-local IP name-address associations
9047 database. Most Operating Systems have such a file on different
9049 - Un*X & Linux: /etc/hosts
9050 - Windows NT/2000: %SystemRoot%\system32\drivers\etc\hosts
9051 (%SystemRoot% value install default is c:\winnt)
9052 - Windows XP/2003: %SystemRoot%\system32\drivers\etc\hosts
9053 (%SystemRoot% value install default is c:\windows)
9054 - Windows 9x/Me: %windir%\hosts
9055 (%windir% value is usually c:\windows)
9056 - Cygwin: /etc/hosts
9058 The file contains newline-separated definitions, in the
9059 form ip_address_in_dotted_form name [name ...] names are
9060 whitespace-separated. Lines beginning with an hash (#)
9061 character are comments.
9063 The file is checked at startup and upon configuration.
9064 If set to 'none', it won't be checked.
9065 If append_domain is used, that domain will be added to
9066 domain-local (i.e. not containing any dot character) host
9072 LOC: Config.appendDomain
9074 DEFAULT_DOC: Use operating system definitions
9076 Appends local domain name to hostnames without any dots in
9077 them. append_domain must begin with a period.
9079 Be warned there are now Internet names with no dots in
9080 them using only top-domain names, so setting this may
9081 cause some Internet sites to become unavailable.
9084 append_domain .yourdomain.com
9087 NAME: ignore_unknown_nameservers
9089 LOC: Config.onoff.ignore_unknown_nameservers
9092 By default Squid checks that DNS responses are received
9093 from the same IP addresses they are sent to. If they
9094 don't match, Squid ignores the response and writes a warning
9095 message to cache.log. You can allow responses from unknown
9096 nameservers by setting this option to 'off'.
9102 LOC: Config.dns.v4_first
9104 With the IPv6 Internet being as fast or faster than IPv4 Internet
9105 for most networks Squid prefers to contact websites over IPv6.
9107 This option reverses the order of preference to make Squid contact
9108 dual-stack websites over IPv4 first. Squid will still perform both
9109 IPv6 and IPv4 DNS lookups before connecting.
9112 This option will restrict the situations under which IPv6
9113 connectivity is used (and tested). Hiding network problems
9114 which would otherwise be detected and warned about.
9118 COMMENT: (number of entries)
9121 LOC: Config.ipcache.size
9123 Maximum number of DNS IP cache entries.
9130 LOC: Config.ipcache.low
9137 LOC: Config.ipcache.high
9139 The size, low-, and high-water marks for the IP cache.
9142 NAME: fqdncache_size
9143 COMMENT: (number of entries)
9146 LOC: Config.fqdncache.size
9148 Maximum number of FQDN cache entries.
9153 -----------------------------------------------------------------------------
9156 NAME: configuration_includes_quoted_values
9158 TYPE: configuration_includes_quoted_values
9160 LOC: ConfigParser::RecognizeQuotedValues
9162 If set, Squid will recognize each "quoted string" after a configuration
9163 directive as a single parameter. The quotes are stripped before the
9164 parameter value is interpreted or used.
9165 See "Values with spaces, quotes, and other special characters"
9166 section for more details.
9173 LOC: Config.onoff.mem_pools
9175 If set, Squid will keep pools of allocated (but unused) memory
9176 available for future use. If memory is a premium on your
9177 system and you believe your malloc library outperforms Squid
9178 routines, disable this.
9181 NAME: memory_pools_limit
9185 LOC: Config.MemPools.limit
9187 Used only with memory_pools on:
9188 memory_pools_limit 50 MB
9190 If set to a non-zero value, Squid will keep at most the specified
9191 limit of allocated (but unused) memory in memory pools. All free()
9192 requests that exceed this limit will be handled by your malloc
9193 library. Squid does not pre-allocate any memory, just safe-keeps
9194 objects that otherwise would be free()d. Thus, it is safe to set
9195 memory_pools_limit to a reasonably high value even if your
9196 configuration will use less memory.
9198 If set to none, Squid will keep all memory it can. That is, there
9199 will be no limit on the total amount of memory used for safe-keeping.
9201 To disable memory allocation optimization, do not set
9202 memory_pools_limit to 0 or none. Set memory_pools to "off" instead.
9204 An overhead for maintaining memory pools is not taken into account
9205 when the limit is checked. This overhead is close to four bytes per
9206 object kept. However, pools may actually _save_ memory because of
9207 reduced memory thrashing in your malloc library.
9211 COMMENT: on|off|transparent|truncate|delete
9214 LOC: opt_forwarded_for
9216 If set to "on", Squid will append your client's IP address
9217 in the HTTP requests it forwards. By default it looks like:
9219 X-Forwarded-For: 192.1.2.3
9221 If set to "off", it will appear as
9223 X-Forwarded-For: unknown
9225 If set to "transparent", Squid will not alter the
9226 X-Forwarded-For header in any way.
9228 If set to "delete", Squid will delete the entire
9229 X-Forwarded-For header.
9231 If set to "truncate", Squid will remove all existing
9232 X-Forwarded-For entries, and place the client IP as the sole entry.
9235 NAME: cachemgr_passwd
9236 TYPE: cachemgrpasswd
9238 DEFAULT_DOC: No password. Actions which require password are denied.
9239 LOC: Config.passwd_list
9241 Specify passwords for cachemgr operations.
9243 Usage: cachemgr_passwd password action action ...
9245 Some valid actions are (see cache manager menu for a full list):
9285 * Indicates actions which will not be performed without a
9286 valid password, others can be performed if not listed here.
9288 To disable an action, set the password to "disable".
9289 To allow performing an action without a password, set the
9292 Use the keyword "all" to set the same password for all actions.
9295 cachemgr_passwd secret shutdown
9296 cachemgr_passwd lesssssssecret info stats/objects
9297 cachemgr_passwd disable all
9304 LOC: Config.onoff.client_db
9306 If you want to disable collecting per-client statistics,
9307 turn off client_db here.
9310 NAME: refresh_all_ims
9314 LOC: Config.onoff.refresh_all_ims
9316 When you enable this option, squid will always check
9317 the origin server for an update when a client sends an
9318 If-Modified-Since request. Many browsers use IMS
9319 requests when the user requests a reload, and this
9320 ensures those clients receive the latest version.
9322 By default (off), squid may return a Not Modified response
9323 based on the age of the cached version.
9326 NAME: reload_into_ims
9327 IFDEF: USE_HTTP_VIOLATIONS
9331 LOC: Config.onoff.reload_into_ims
9333 When you enable this option, client no-cache or ``reload''
9334 requests will be changed to If-Modified-Since requests.
9335 Doing this VIOLATES the HTTP standard. Enabling this
9336 feature could make you liable for problems which it
9339 see also refresh_pattern for a more selective approach.
9342 NAME: connect_retries
9344 LOC: Config.connect_retries
9346 DEFAULT_DOC: Do not retry failed connections.
9348 This sets the maximum number of connection attempts made for each
9349 TCP connection. The connect_retries attempts must all still
9350 complete within the connection timeout period.
9352 The default is not to re-try if the first connection attempt fails.
9353 The (not recommended) maximum is 10 tries.
9355 A warning message will be generated if it is set to a too-high
9356 value and the configured value will be over-ridden.
9358 Note: These re-tries are in addition to forward_max_tries
9359 which limit how many different addresses may be tried to find
9363 NAME: retry_on_error
9365 LOC: Config.retry.onerror
9368 If set to ON Squid will automatically retry requests when
9369 receiving an error response with status 403 (Forbidden),
9370 500 (Internal Error), 501 or 503 (Service not available).
9371 Status 502 and 504 (Gateway errors) are always retried.
9373 This is mainly useful if you are in a complex cache hierarchy to
9374 work around access control errors.
9376 NOTE: This retry will attempt to find another working destination.
9377 Which is different from the server which just failed.
9380 NAME: as_whois_server
9382 LOC: Config.as_whois_server
9383 DEFAULT: whois.ra.net
9385 WHOIS server to query for AS numbers. NOTE: AS numbers are
9386 queried only when Squid starts up, not for every request.
9391 LOC: Config.onoff.offline
9394 Enable this option and Squid will never try to validate cached
9398 NAME: uri_whitespace
9399 TYPE: uri_whitespace
9400 LOC: Config.uri_whitespace
9403 What to do with requests that have whitespace characters in the
9406 strip: The whitespace characters are stripped out of the URL.
9407 This is the behavior recommended by RFC2396 and RFC3986
9408 for tolerant handling of generic URI.
9409 NOTE: This is one difference between generic URI and HTTP URLs.
9411 deny: The request is denied. The user receives an "Invalid
9413 This is the behaviour recommended by RFC2616 for safe
9414 handling of HTTP request URL.
9416 allow: The request is allowed and the URI is not changed. The
9417 whitespace characters remain in the URI. Note the
9418 whitespace is passed to redirector processes if they
9420 Note this may be considered a violation of RFC2616
9421 request parsing where whitespace is prohibited in the
9424 encode: The request is allowed and the whitespace characters are
9425 encoded according to RFC1738.
9427 chop: The request is allowed and the URI is chopped at the
9431 NOTE the current Squid implementation of encode and chop violates
9432 RFC2616 by not using a 301 redirect after altering the URL.
9437 LOC: Config.chroot_dir
9440 Specifies a directory where Squid should do a chroot() while
9441 initializing. This also causes Squid to fully drop root
9442 privileges after initializing. This means, for example, if you
9443 use a HTTP port less than 1024 and try to reconfigure, you may
9444 get an error saying that Squid can not open the port.
9447 NAME: balance_on_multiple_ip
9449 LOC: Config.onoff.balance_on_multiple_ip
9452 Modern IP resolvers in squid sort lookup results by preferred access.
9453 By default squid will use these IP in order and only rotates to
9454 the next listed when the most preffered fails.
9456 Some load balancing servers based on round robin DNS have been
9457 found not to preserve user session state across requests
9458 to different IP addresses.
9460 Enabling this directive Squid rotates IP's per request.
9463 NAME: pipeline_prefetch
9464 TYPE: pipelinePrefetch
9465 LOC: Config.pipeline_max_prefetch
9467 DEFAULT_DOC: Do not pre-parse pipelined requests.
9469 HTTP clients may send a pipeline of 1+N requests to Squid using a
9470 single connection, without waiting for Squid to respond to the first
9471 of those requests. This option limits the number of concurrent
9472 requests Squid will try to handle in parallel. If set to N, Squid
9473 will try to receive and process up to 1+N requests on the same
9474 connection concurrently.
9476 Defaults to 0 (off) for bandwidth management and access logging
9479 NOTE: pipelining requires persistent connections to clients.
9481 WARNING: pipelining breaks NTLM and Negotiate/Kerberos authentication.
9484 NAME: high_response_time_warning
9487 LOC: Config.warnings.high_rptm
9489 DEFAULT_DOC: disabled.
9491 If the one-minute median response time exceeds this value,
9492 Squid prints a WARNING with debug level 0 to get the
9493 administrators attention. The value is in milliseconds.
9496 NAME: high_page_fault_warning
9498 LOC: Config.warnings.high_pf
9500 DEFAULT_DOC: disabled.
9502 If the one-minute average page fault rate exceeds this
9503 value, Squid prints a WARNING with debug level 0 to get
9504 the administrators attention. The value is in page faults
9508 NAME: high_memory_warning
9510 LOC: Config.warnings.high_memory
9511 IFDEF: HAVE_MSTATS&&HAVE_GNUMALLOC_H
9513 DEFAULT_DOC: disabled.
9515 If the memory usage (as determined by gnumalloc, if available and used)
9516 exceeds this amount, Squid prints a WARNING with debug level 0 to get
9517 the administrators attention.
9519 # TODO: link high_memory_warning to mempools?
9521 NAME: sleep_after_fork
9522 COMMENT: (microseconds)
9524 LOC: Config.sleep_after_fork
9527 When this is set to a non-zero value, the main Squid process
9528 sleeps the specified number of microseconds after a fork()
9529 system call. This sleep may help the situation where your
9530 system reports fork() failures due to lack of (virtual)
9531 memory. Note, however, if you have a lot of child
9532 processes, these sleep delays will add up and your
9533 Squid will not service requests for some amount of time
9534 until all the child processes have been started.
9535 On Windows value less then 1000 (1 milliseconds) are
9539 NAME: windows_ipaddrchangemonitor
9540 IFDEF: _SQUID_WINDOWS_
9544 LOC: Config.onoff.WIN32_IpAddrChangeMonitor
9546 On Windows Squid by default will monitor IP address changes and will
9547 reconfigure itself after any detected event. This is very useful for
9548 proxies connected to internet with dial-up interfaces.
9549 In some cases (a Proxy server acting as VPN gateway is one) it could be
9550 desiderable to disable this behaviour setting this to 'off'.
9551 Note: after changing this, Squid service must be restarted.
9556 IFDEF: USE_SQUID_EUI
9558 LOC: Eui::TheConfig.euiLookup
9560 Whether to lookup the EUI or MAC address of a connected client.
9563 NAME: max_filedescriptors max_filedesc
9566 DEFAULT_DOC: Use operating system limits set by ulimit.
9567 LOC: Config.max_filedescriptors
9569 Reduce the maximum number of filedescriptors supported below
9570 the usual operating system defaults.
9572 Remove from squid.conf to inherit the current ulimit setting.
9574 Note: Changing this requires a restart of Squid. Also
9575 not all I/O types supports large values (eg on Windows).
9578 NAME: force_request_body_continuation
9580 LOC: Config.accessList.forceRequestBodyContinuation
9582 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
9584 This option controls how Squid handles data upload requests from HTTP
9585 and FTP agents that require a "Please Continue" control message response
9586 to actually send the request body to Squid. It is mostly useful in
9587 adaptation environments.
9589 When Squid receives an HTTP request with an "Expect: 100-continue"
9590 header or an FTP upload command (e.g., STOR), Squid normally sends the
9591 request headers or FTP command information to an adaptation service (or
9592 peer) and waits for a response. Most adaptation services (and some
9593 broken peers) may not respond to Squid at that stage because they may
9594 decide to wait for the HTTP request body or FTP data transfer. However,
9595 that request body or data transfer may never come because Squid has not
9596 responded with the HTTP 100 or FTP 150 (Please Continue) control message
9597 to the request sender yet!
9599 An allow match tells Squid to respond with the HTTP 100 or FTP 150
9600 (Please Continue) control message on its own, before forwarding the
9601 request to an adaptation service or peer. Such a response usually forces
9602 the request sender to proceed with sending the body. A deny match tells
9603 Squid to delay that control response until the origin server confirms
9604 that the request body is needed. Delaying is the default behavior.
projects / thirdparty / squid.git / blob