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 specifications
766 %LOGIN Authenticated user login name
767 %EXT_USER Username from previous external acl
768 %EXT_LOG Log details from previous external acl
769 %EXT_TAG Tag from previous external acl
770 %IDENT Ident user name
772 %SRCPORT Client source port
775 %PROTO Requested URL scheme
777 %PATH Requested URL path
778 %METHOD Request method
779 %MYADDR Squid interface address
780 %MYPORT Squid http_port number
781 %PATH Requested URL-path (including query-string if any)
782 %USER_CERT SSL User certificate in PEM format
783 %USER_CERTCHAIN SSL User certificate chain in PEM format
784 %USER_CERT_xx SSL User certificate subject attribute xx
785 %USER_CA_CERT_xx SSL User certificate issuer attribute xx
786 %ssl::>sni SSL client SNI sent to Squid
787 %ssl::<cert_subject SSL server certificate DN
788 %ssl::<cert_issuer SSL server certificate issuer DN
790 %>{Header} HTTP request header "Header"
792 HTTP request header "Hdr" list member "member"
794 HTTP request header list member using ; as
795 list separator. ; can be any non-alphanumeric
798 %<{Header} HTTP reply header "Header"
800 HTTP reply header "Hdr" list member "member"
802 HTTP reply header list member using ; as
803 list separator. ; can be any non-alphanumeric
806 %ACL The name of the ACL being tested.
807 %DATA The ACL arguments. If not used then any arguments
808 is automatically added at the end of the line
810 NOTE: this will encode the arguments as one token,
811 whereas the default will pass each separately.
813 %% The percent sign. Useful for helpers which need
814 an unchanging input format.
817 General request syntax:
819 [channel-ID] FORMAT-values [acl-values ...]
822 FORMAT-values consists of transaction details expanded with
823 whitespace separation per the config file FORMAT specification
824 using the FORMAT macros listed above.
826 acl-values consists of any string specified in the referencing
827 config 'acl ... external' line. see the "acl external" directive.
829 Request values sent to the helper are URL escaped to protect
830 each value in requests against whitespaces.
832 If using protocol=2.5 then the request sent to the helper is not
833 URL escaped to protect against whitespace.
835 NOTE: protocol=3.0 is deprecated as no longer necessary.
837 When using the concurrency= option the protocol is changed by
838 introducing a query channel tag in front of the request/response.
839 The query channel tag is a number between 0 and concurrency-1.
840 This value must be echoed back unchanged to Squid as the first part
841 of the response relating to its request.
844 The helper receives lines expanded per the above format specification
845 and for each input line returns 1 line starting with OK/ERR/BH result
846 code and optionally followed by additional keywords with more details.
849 General result syntax:
851 [channel-ID] result keyword=value ...
853 Result consists of one of the codes:
856 the ACL test produced a match.
859 the ACL test does not produce a match.
862 An internal error occurred in the helper, preventing
863 a result being identified.
865 The meaning of 'a match' is determined by your squid.conf
866 access control configuration. See the Squid wiki for details.
870 user= The users name (login)
872 password= The users password (for login= cache_peer option)
874 message= Message describing the reason for this response.
875 Available as %o in error pages.
876 Useful on (ERR and BH results).
878 tag= Apply a tag to a request. Only sets a tag once,
879 does not alter existing tags.
881 log= String to be logged in access.log. Available as
882 %ea in logformat specifications.
884 clt_conn_tag= Associates a TAG with the client TCP connection.
885 Please see url_rewrite_program related documentation
888 Any keywords may be sent on any response whether OK, ERR or BH.
890 All response keyword values need to be a single token with URL
891 escaping, or enclosed in double quotes (") and escaped using \ on
892 any double quotes or \ characters within the value. The wrapping
893 double quotes are removed before the value is interpreted by Squid.
894 \r and \n are also replace by CR and LF.
896 Some example key values:
900 user="J. \"Bob\" Smith"
907 DEFAULT: ssl::certHasExpired ssl_error X509_V_ERR_CERT_HAS_EXPIRED
908 DEFAULT: ssl::certNotYetValid ssl_error X509_V_ERR_CERT_NOT_YET_VALID
909 DEFAULT: ssl::certDomainMismatch ssl_error SQUID_X509_V_ERR_DOMAIN_MISMATCH
910 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
911 DEFAULT: ssl::certSelfSigned ssl_error X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT
914 DEFAULT: manager url_regex -i ^cache_object:// +i ^https?://[^/]+/squid-internal-mgr/
915 DEFAULT: localhost src 127.0.0.1/32 ::1
916 DEFAULT: to_localhost dst 127.0.0.0/8 0.0.0.0/32 ::1
917 DEFAULT_DOC: ACLs all, manager, localhost, and to_localhost are predefined.
919 Defining an Access List
921 Every access list definition must begin with an aclname and acltype,
922 followed by either type-specific arguments or a quoted filename that
925 acl aclname acltype argument ...
926 acl aclname acltype "file" ...
928 When using "file", the file should contain one item per line.
930 Some acl types supports options which changes their default behaviour.
931 The available options are:
933 -i,+i By default, regular expressions are CASE-SENSITIVE. To make them
934 case-insensitive, use the -i option. To return case-sensitive
935 use the +i option between patterns, or make a new ACL line
938 -n Disable lookups and address type conversions. If lookup or
939 conversion is required because the parameter type (IP or
940 domain name) does not match the message address type (domain
941 name or IP), then the ACL would immediately declare a mismatch
942 without any warnings or lookups.
944 -- Used to stop processing all options, in the case the first acl
945 value has '-' character as first character (for example the '-'
946 is a valid domain name)
948 Some acl types require suspending the current request in order
949 to access some external data source.
950 Those which do are marked with the tag [slow], those which
951 don't are marked as [fast].
952 See http://wiki.squid-cache.org/SquidFaq/SquidAcl
953 for further information
955 ***** ACL TYPES AVAILABLE *****
957 acl aclname src ip-address/mask ... # clients IP address [fast]
958 acl aclname src addr1-addr2/mask ... # range of addresses [fast]
959 acl aclname dst [-n] ip-address/mask ... # URL host's IP address [slow]
960 acl aclname localip ip-address/mask ... # IP address the client connected to [fast]
962 acl aclname arp mac-address ... (xx:xx:xx:xx:xx:xx notation)
963 # The arp ACL requires the special configure option --enable-arp-acl.
964 # Furthermore, the ARP ACL code is not portable to all operating systems.
965 # It works on Linux, Solaris, Windows, FreeBSD, and some
966 # other *BSD variants.
969 # NOTE: Squid can only determine the MAC address for clients that are on
970 # the same subnet. If the client is on a different subnet,
971 # then Squid cannot find out its MAC address.
973 acl aclname srcdomain .foo.com ...
974 # reverse lookup, from client IP [slow]
975 acl aclname dstdomain [-n] .foo.com ...
976 # Destination server from URL [fast]
977 acl aclname srcdom_regex [-i] \.foo\.com ...
978 # regex matching client name [slow]
979 acl aclname dstdom_regex [-n] [-i] \.foo\.com ...
980 # regex matching server [fast]
982 # For dstdomain and dstdom_regex a reverse lookup is tried if a IP
983 # based URL is used and no match is found. The name "none" is used
984 # if the reverse lookup fails.
986 acl aclname src_as number ...
987 acl aclname dst_as number ...
989 # Except for access control, AS numbers can be used for
990 # routing of requests to specific caches. Here's an
991 # example for routing all requests for AS#1241 and only
992 # those to mycache.mydomain.net:
993 # acl asexample dst_as 1241
994 # cache_peer_access mycache.mydomain.net allow asexample
995 # cache_peer_access mycache_mydomain.net deny all
997 acl aclname peername myPeer ...
999 # match against a named cache_peer entry
1000 # set unique name= on cache_peer lines for reliable use.
1002 acl aclname time [day-abbrevs] [h1:m1-h2:m2]
1012 # h1:m1 must be less than h2:m2
1014 acl aclname url_regex [-i] ^http:// ...
1015 # regex matching on whole URL [fast]
1016 acl aclname urllogin [-i] [^a-zA-Z0-9] ...
1017 # regex matching on URL login field
1018 acl aclname urlpath_regex [-i] \.gif$ ...
1019 # regex matching on URL path [fast]
1021 acl aclname port 80 70 21 0-1024... # destination TCP port [fast]
1023 acl aclname localport 3128 ... # TCP port the client connected to [fast]
1024 # NP: for interception mode this is usually '80'
1026 acl aclname myportname 3128 ... # *_port name [fast]
1028 acl aclname proto HTTP FTP ... # request protocol [fast]
1030 acl aclname method GET POST ... # HTTP request method [fast]
1032 acl aclname http_status 200 301 500- 400-403 ...
1033 # status code in reply [fast]
1035 acl aclname browser [-i] regexp ...
1036 # pattern match on User-Agent header (see also req_header below) [fast]
1038 acl aclname referer_regex [-i] regexp ...
1039 # pattern match on Referer header [fast]
1040 # Referer is highly unreliable, so use with care
1042 acl aclname ident username ...
1043 acl aclname ident_regex [-i] pattern ...
1044 # string match on ident output [slow]
1045 # use REQUIRED to accept any non-null ident.
1047 acl aclname proxy_auth [-i] username ...
1048 acl aclname proxy_auth_regex [-i] pattern ...
1049 # perform http authentication challenge to the client and match against
1050 # supplied credentials [slow]
1052 # takes a list of allowed usernames.
1053 # use REQUIRED to accept any valid username.
1055 # Will use proxy authentication in forward-proxy scenarios, and plain
1056 # http authenticaiton in reverse-proxy scenarios
1058 # NOTE: when a Proxy-Authentication header is sent but it is not
1059 # needed during ACL checking the username is NOT logged
1062 # NOTE: proxy_auth requires a EXTERNAL authentication program
1063 # to check username/password combinations (see
1064 # auth_param directive).
1066 # NOTE: proxy_auth can't be used in a transparent/intercepting proxy
1067 # as the browser needs to be configured for using a proxy in order
1068 # to respond to proxy authentication.
1070 acl aclname snmp_community string ...
1071 # A community string to limit access to your SNMP Agent [fast]
1074 # acl snmppublic snmp_community public
1076 acl aclname maxconn number
1077 # This will be matched when the client's IP address has
1078 # more than <number> TCP connections established. [fast]
1079 # NOTE: This only measures direct TCP links so X-Forwarded-For
1080 # indirect clients are not counted.
1082 acl aclname max_user_ip [-s] number
1083 # This will be matched when the user attempts to log in from more
1084 # than <number> different ip addresses. The authenticate_ip_ttl
1085 # parameter controls the timeout on the ip entries. [fast]
1086 # If -s is specified the limit is strict, denying browsing
1087 # from any further IP addresses until the ttl has expired. Without
1088 # -s Squid will just annoy the user by "randomly" denying requests.
1089 # (the counter is reset each time the limit is reached and a
1090 # request is denied)
1091 # NOTE: in acceleration mode or where there is mesh of child proxies,
1092 # clients may appear to come from multiple addresses if they are
1093 # going through proxy farms, so a limit of 1 may cause user problems.
1095 acl aclname random probability
1096 # Pseudo-randomly match requests. Based on the probability given.
1097 # Probability may be written as a decimal (0.333), fraction (1/3)
1098 # or ratio of matches:non-matches (3:5).
1100 acl aclname req_mime_type [-i] mime-type ...
1101 # regex match against the mime type of the request generated
1102 # by the client. Can be used to detect file upload or some
1103 # types HTTP tunneling requests [fast]
1104 # NOTE: This does NOT match the reply. You cannot use this
1105 # to match the returned file type.
1107 acl aclname req_header header-name [-i] any\.regex\.here
1108 # regex match against any of the known request headers. May be
1109 # thought of as a superset of "browser", "referer" and "mime-type"
1112 acl aclname rep_mime_type [-i] mime-type ...
1113 # regex match against the mime type of the reply received by
1114 # squid. Can be used to detect file download or some
1115 # types HTTP tunneling requests. [fast]
1116 # NOTE: This has no effect in http_access rules. It only has
1117 # effect in rules that affect the reply data stream such as
1118 # http_reply_access.
1120 acl aclname rep_header header-name [-i] any\.regex\.here
1121 # regex match against any of the known reply headers. May be
1122 # thought of as a superset of "browser", "referer" and "mime-type"
1125 acl aclname external class_name [arguments...]
1126 # external ACL lookup via a helper class defined by the
1127 # external_acl_type directive [slow]
1129 acl aclname user_cert attribute values...
1130 # match against attributes in a user SSL certificate
1131 # attribute is one of DN/C/O/CN/L/ST or a numerical OID [fast]
1133 acl aclname ca_cert attribute values...
1134 # match against attributes a users issuing CA SSL certificate
1135 # attribute is one of DN/C/O/CN/L/ST or a numerical OID [fast]
1137 acl aclname ext_user username ...
1138 acl aclname ext_user_regex [-i] pattern ...
1139 # string match on username returned by external acl helper [slow]
1140 # use REQUIRED to accept any non-null user name.
1142 acl aclname tag tagvalue ...
1143 # string match on tag returned by external acl helper [fast]
1144 # DEPRECATED. Only the first tag will match with this ACL.
1145 # Use the 'note' ACL instead for handling multiple tag values.
1147 acl aclname hier_code codename ...
1148 # string match against squid hierarchy code(s); [fast]
1149 # e.g., DIRECT, PARENT_HIT, NONE, etc.
1151 # NOTE: This has no effect in http_access rules. It only has
1152 # effect in rules that affect the reply data stream such as
1153 # http_reply_access.
1155 acl aclname note name [value ...]
1156 # match transaction annotation [fast]
1157 # Without values, matches any annotation with a given name.
1158 # With value(s), matches any annotation with a given name that
1159 # also has one of the given values.
1160 # Names and values are compared using a string equality test.
1161 # Annotation sources include note and adaptation_meta directives
1162 # as well as helper and eCAP responses.
1164 acl aclname adaptation_service service ...
1165 # Matches the name of any icap_service, ecap_service,
1166 # adaptation_service_set, or adaptation_service_chain that Squid
1167 # has used (or attempted to use) for the master transaction.
1168 # This ACL must be defined after the corresponding adaptation
1169 # service is named in squid.conf. This ACL is usable with
1170 # adaptation_meta because it starts matching immediately after
1171 # the service has been selected for adaptation.
1174 acl aclname ssl_error errorname
1175 # match against SSL certificate validation error [fast]
1177 # For valid error names see in @DEFAULT_ERROR_DIR@/templates/error-details.txt
1180 # The following can be used as shortcuts for certificate properties:
1181 # [ssl::]certHasExpired: the "not after" field is in the past
1182 # [ssl::]certNotYetValid: the "not before" field is in the future
1183 # [ssl::]certUntrusted: The certificate issuer is not to be trusted.
1184 # [ssl::]certSelfSigned: The certificate is self signed.
1185 # [ssl::]certDomainMismatch: The certificate CN domain does not
1186 # match the name the name of the host we are connecting to.
1188 # The ssl::certHasExpired, ssl::certNotYetValid, ssl::certDomainMismatch,
1189 # ssl::certUntrusted, and ssl::certSelfSigned can also be used as
1190 # predefined ACLs, just like the 'all' ACL.
1192 # NOTE: The ssl_error ACL is only supported with sslproxy_cert_error,
1193 # sslproxy_cert_sign, and sslproxy_cert_adapt options.
1195 acl aclname server_cert_fingerprint [-sha1] fingerprint
1196 # match against server SSL certificate fingerprint [fast]
1198 # The fingerprint is the digest of the DER encoded version
1199 # of the whole certificate. The user should use the form: XX:XX:...
1200 # Optional argument specifies the digest algorithm to use.
1201 # The SHA1 digest algorithm is the default and is currently
1202 # the only algorithm supported (-sha1).
1204 acl aclname at_step step
1205 # match against the current step during ssl_bump evaluation [fast]
1206 # Never matches and should not be used outside the ssl_bump context.
1208 # At each SslBump step, Squid evaluates ssl_bump directives to find
1209 # the next bumping action (e.g., peek or splice). Valid SslBump step
1210 # values and the corresponding ssl_bump evaluation moments are:
1211 # SslBump1: After getting TCP-level and HTTP CONNECT info.
1212 # SslBump2: After getting SSL Client Hello info.
1213 # SslBump3: After getting SSL Server Hello info.
1215 acl aclname ssl::server_name .foo.com ...
1216 # matches server name obtained from various sources [fast]
1218 # The server name is obtained during Ssl-Bump steps from such sources
1219 # as CONNECT request URI, client SNI, and SSL server certificate CN.
1220 # During each Ssl-Bump step, Squid may improve its understanding of a
1221 # "true server name". Unlike dstdomain, this ACL does not perform
1224 acl aclname ssl::server_name_regex [-i] \.foo\.com ...
1225 # regex matches server name obtained from various sources [fast]
1227 acl aclname any-of acl1 acl2 ...
1228 # match any one of the acls [fast or slow]
1229 # The first matching ACL stops further ACL evaluation.
1231 # ACLs from multiple any-of lines with the same name are ORed.
1232 # For example, A = (a1 or a2) or (a3 or a4) can be written as
1233 # acl A any-of a1 a2
1234 # acl A any-of a3 a4
1236 # This group ACL is fast if all evaluated ACLs in the group are fast
1237 # and slow otherwise.
1239 acl aclname all-of acl1 acl2 ...
1240 # match all of the acls [fast or slow]
1241 # The first mismatching ACL stops further ACL evaluation.
1243 # ACLs from multiple all-of lines with the same name are ORed.
1244 # For example, B = (b1 and b2) or (b3 and b4) can be written as
1245 # acl B all-of b1 b2
1246 # acl B all-of b3 b4
1248 # This group ACL is fast if all evaluated ACLs in the group are fast
1249 # and slow otherwise.
1252 acl macaddress arp 09:00:2b:23:45:67
1253 acl myexample dst_as 1241
1254 acl password proxy_auth REQUIRED
1255 acl fileupload req_mime_type -i ^multipart/form-data$
1256 acl javascript rep_mime_type -i ^application/x-javascript$
1260 # Recommended minimum configuration:
1263 # Example rule allowing access from your local networks.
1264 # Adapt to list your (internal) IP networks from where browsing
1266 acl localnet src 0.0.0.1-0.255.255.255 # RFC 1122 "this" network (LAN)
1267 acl localnet src 10.0.0.0/8 # RFC 1918 local private network (LAN)
1268 acl localnet src 100.64.0.0/10 # RFC 6598 shared address space (CGN)
1269 acl localhet src 169.254.0.0/16 # RFC 3927 link-local (directly plugged) machines
1270 acl localnet src 172.16.0.0/12 # RFC 1918 local private network (LAN)
1271 acl localnet src 192.168.0.0/16 # RFC 1918 local private network (LAN)
1272 acl localnet src fc00::/7 # RFC 4193 local private network range
1273 acl localnet src fe80::/10 # RFC 4291 link-local (directly plugged) machines
1275 acl SSL_ports port 443
1276 acl Safe_ports port 80 # http
1277 acl Safe_ports port 21 # ftp
1278 acl Safe_ports port 443 # https
1279 acl Safe_ports port 70 # gopher
1280 acl Safe_ports port 210 # wais
1281 acl Safe_ports port 1025-65535 # unregistered ports
1282 acl Safe_ports port 280 # http-mgmt
1283 acl Safe_ports port 488 # gss-http
1284 acl Safe_ports port 591 # filemaker
1285 acl Safe_ports port 777 # multiling http
1286 acl CONNECT method CONNECT
1290 NAME: proxy_protocol_access
1292 LOC: Config.accessList.proxyProtocol
1294 DEFAULT_DOC: all TCP connections to ports with require-proxy-header will be denied
1296 Determine which client proxies can be trusted to provide correct
1297 information regarding real client IP address using PROXY protocol.
1299 Requests may pass through a chain of several other proxies
1300 before reaching us. The original source details may by sent in:
1301 * HTTP message Forwarded header, or
1302 * HTTP message X-Forwarded-For header, or
1303 * PROXY protocol connection header.
1305 This directive is solely for validating new PROXY protocol
1306 connections received from a port flagged with require-proxy-header.
1307 It is checked only once after TCP connection setup.
1309 A deny match results in TCP connection closure.
1311 An allow match is required for Squid to permit the corresponding
1312 TCP connection, before Squid even looks for HTTP request headers.
1313 If there is an allow match, Squid starts using PROXY header information
1314 to determine the source address of the connection for all future ACL
1315 checks, logging, etc.
1317 SECURITY CONSIDERATIONS:
1319 Any host from which we accept client IP details can place
1320 incorrect information in the relevant header, and Squid
1321 will use the incorrect information as if it were the
1322 source address of the request. This may enable remote
1323 hosts to bypass any access control restrictions that are
1324 based on the client's source addresses.
1326 This clause only supports fast acl types.
1327 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1330 NAME: follow_x_forwarded_for
1332 IFDEF: FOLLOW_X_FORWARDED_FOR
1333 LOC: Config.accessList.followXFF
1334 DEFAULT_IF_NONE: deny all
1335 DEFAULT_DOC: X-Forwarded-For header will be ignored.
1337 Determine which client proxies can be trusted to provide correct
1338 information regarding real client IP address.
1340 Requests may pass through a chain of several other proxies
1341 before reaching us. The original source details may by sent in:
1342 * HTTP message Forwarded header, or
1343 * HTTP message X-Forwarded-For header, or
1344 * PROXY protocol connection header.
1346 PROXY protocol connections are controlled by the proxy_protocol_access
1347 directive which is checked before this.
1349 If a request reaches us from a source that is allowed by this
1350 directive, then we trust the information it provides regarding
1351 the IP of the client it received from (if any).
1353 For the purpose of ACLs used in this directive the src ACL type always
1354 matches the address we are testing and srcdomain matches its rDNS.
1356 On each HTTP request Squid checks for X-Forwarded-For header fields.
1357 If found the header values are iterated in reverse order and an allow
1358 match is required for Squid to continue on to the next value.
1359 The verification ends when a value receives a deny match, cannot be
1360 tested, or there are no more values to test.
1361 NOTE: Squid does not yet follow the Forwarded HTTP header.
1363 The end result of this process is an IP address that we will
1364 refer to as the indirect client address. This address may
1365 be treated as the client address for access control, ICAP, delay
1366 pools and logging, depending on the acl_uses_indirect_client,
1367 icap_uses_indirect_client, delay_pool_uses_indirect_client,
1368 log_uses_indirect_client and tproxy_uses_indirect_client options.
1370 This clause only supports fast acl types.
1371 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1373 SECURITY CONSIDERATIONS:
1375 Any host from which we accept client IP details can place
1376 incorrect information in the relevant header, and Squid
1377 will use the incorrect information as if it were the
1378 source address of the request. This may enable remote
1379 hosts to bypass any access control restrictions that are
1380 based on the client's source addresses.
1384 acl localhost src 127.0.0.1
1385 acl my_other_proxy srcdomain .proxy.example.com
1386 follow_x_forwarded_for allow localhost
1387 follow_x_forwarded_for allow my_other_proxy
1390 NAME: acl_uses_indirect_client
1393 IFDEF: FOLLOW_X_FORWARDED_FOR
1395 LOC: Config.onoff.acl_uses_indirect_client
1397 Controls whether the indirect client address
1398 (see follow_x_forwarded_for) is used instead of the
1399 direct client address in acl matching.
1401 NOTE: maxconn ACL considers direct TCP links and indirect
1402 clients will always have zero. So no match.
1405 NAME: delay_pool_uses_indirect_client
1408 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_DELAY_POOLS
1410 LOC: Config.onoff.delay_pool_uses_indirect_client
1412 Controls whether the indirect client address
1413 (see follow_x_forwarded_for) is used instead of the
1414 direct client address in delay pools.
1417 NAME: log_uses_indirect_client
1420 IFDEF: FOLLOW_X_FORWARDED_FOR
1422 LOC: Config.onoff.log_uses_indirect_client
1424 Controls whether the indirect client address
1425 (see follow_x_forwarded_for) is used instead of the
1426 direct client address in the access log.
1429 NAME: tproxy_uses_indirect_client
1432 IFDEF: FOLLOW_X_FORWARDED_FOR&&LINUX_NETFILTER
1434 LOC: Config.onoff.tproxy_uses_indirect_client
1436 Controls whether the indirect client address
1437 (see follow_x_forwarded_for) is used instead of the
1438 direct client address when spoofing the outgoing client.
1440 This has no effect on requests arriving in non-tproxy
1443 SECURITY WARNING: Usage of this option is dangerous
1444 and should not be used trivially. Correct configuration
1445 of follow_x_forewarded_for with a limited set of trusted
1446 sources is required to prevent abuse of your proxy.
1449 NAME: spoof_client_ip
1451 LOC: Config.accessList.spoof_client_ip
1453 DEFAULT_DOC: Allow spoofing on all TPROXY traffic.
1455 Control client IP address spoofing of TPROXY traffic based on
1456 defined access lists.
1458 spoof_client_ip allow|deny [!]aclname ...
1460 If there are no "spoof_client_ip" lines present, the default
1461 is to "allow" spoofing of any suitable request.
1463 Note that the cache_peer "no-tproxy" option overrides this ACL.
1465 This clause supports fast acl types.
1466 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1471 LOC: Config.accessList.http
1472 DEFAULT_IF_NONE: deny all
1473 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1475 Allowing or Denying access based on defined access lists
1477 To allow or deny a message received on an HTTP, HTTPS, or FTP port:
1478 http_access allow|deny [!]aclname ...
1480 NOTE on default values:
1482 If there are no "access" lines present, the default is to deny
1485 If none of the "access" lines cause a match, the default is the
1486 opposite of the last line in the list. If the last line was
1487 deny, the default is allow. Conversely, if the last line
1488 is allow, the default will be deny. For these reasons, it is a
1489 good idea to have an "deny all" entry at the end of your access
1490 lists to avoid potential confusion.
1492 This clause supports both fast and slow acl types.
1493 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1498 # Recommended minimum Access Permission configuration:
1500 # Deny requests to certain unsafe ports
1501 http_access deny !Safe_ports
1503 # Deny CONNECT to other than secure SSL ports
1504 http_access deny CONNECT !SSL_ports
1506 # Only allow cachemgr access from localhost
1507 http_access allow localhost manager
1508 http_access deny manager
1510 # We strongly recommend the following be uncommented to protect innocent
1511 # web applications running on the proxy server who think the only
1512 # one who can access services on "localhost" is a local user
1513 #http_access deny to_localhost
1516 # INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS
1519 # Example rule allowing access from your local networks.
1520 # Adapt localnet in the ACL section to list your (internal) IP networks
1521 # from where browsing should be allowed
1522 http_access allow localnet
1523 http_access allow localhost
1525 # And finally deny all other access to this proxy
1526 http_access deny all
1530 NAME: adapted_http_access http_access2
1532 LOC: Config.accessList.adapted_http
1534 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1536 Allowing or Denying access based on defined access lists
1538 Essentially identical to http_access, but runs after redirectors
1539 and ICAP/eCAP adaptation. Allowing access control based on their
1542 If not set then only http_access is used.
1545 NAME: http_reply_access
1547 LOC: Config.accessList.reply
1549 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1551 Allow replies to client requests. This is complementary to http_access.
1553 http_reply_access allow|deny [!] aclname ...
1555 NOTE: if there are no access lines present, the default is to allow
1558 If none of the access lines cause a match the opposite of the
1559 last line will apply. Thus it is good practice to end the rules
1560 with an "allow all" or "deny all" entry.
1562 This clause supports both fast and slow acl types.
1563 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1568 LOC: Config.accessList.icp
1570 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1572 Allowing or Denying access to the ICP port based on defined
1575 icp_access allow|deny [!]aclname ...
1577 NOTE: The default if no icp_access lines are present is to
1578 deny all traffic. This default may cause problems with peers
1581 This clause only supports fast acl types.
1582 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1584 # Allow ICP queries from local networks only
1585 #icp_access allow localnet
1586 #icp_access deny all
1592 LOC: Config.accessList.htcp
1594 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1596 Allowing or Denying access to the HTCP port based on defined
1599 htcp_access allow|deny [!]aclname ...
1601 See also htcp_clr_access for details on access control for
1602 cache purge (CLR) HTCP messages.
1604 NOTE: The default if no htcp_access lines are present is to
1605 deny all traffic. This default may cause problems with peers
1606 using the htcp option.
1608 This clause only supports fast acl types.
1609 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1611 # Allow HTCP queries from local networks only
1612 #htcp_access allow localnet
1613 #htcp_access deny all
1616 NAME: htcp_clr_access
1619 LOC: Config.accessList.htcp_clr
1621 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1623 Allowing or Denying access to purge content using HTCP based
1624 on defined access lists.
1625 See htcp_access for details on general HTCP access control.
1627 htcp_clr_access allow|deny [!]aclname ...
1629 This clause only supports fast acl types.
1630 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1632 # Allow HTCP CLR requests from trusted peers
1633 acl htcp_clr_peer src 192.0.2.2 2001:DB8::2
1634 htcp_clr_access allow htcp_clr_peer
1635 htcp_clr_access deny all
1640 LOC: Config.accessList.miss
1642 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1644 Determins whether network access is permitted when satisfying a request.
1647 to force your neighbors to use you as a sibling instead of
1650 acl localclients src 192.0.2.0/24 2001:DB8::a:0/64
1651 miss_access deny !localclients
1652 miss_access allow all
1654 This means only your local clients are allowed to fetch relayed/MISS
1655 replies from the network and all other clients can only fetch cached
1658 The default for this setting allows all clients who passed the
1659 http_access rules to relay via this proxy.
1661 This clause only supports fast acl types.
1662 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1665 NAME: ident_lookup_access
1669 DEFAULT_DOC: Unless rules exist in squid.conf, IDENT is not fetched.
1670 LOC: Ident::TheConfig.identLookup
1672 A list of ACL elements which, if matched, cause an ident
1673 (RFC 931) lookup to be performed for this request. For
1674 example, you might choose to always perform ident lookups
1675 for your main multi-user Unix boxes, but not for your Macs
1676 and PCs. By default, ident lookups are not performed for
1679 To enable ident lookups for specific client addresses, you
1680 can follow this example:
1682 acl ident_aware_hosts src 198.168.1.0/24
1683 ident_lookup_access allow ident_aware_hosts
1684 ident_lookup_access deny all
1686 Only src type ACL checks are fully supported. A srcdomain
1687 ACL might work at times, but it will not always provide
1690 This clause only supports fast acl types.
1691 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1694 NAME: reply_body_max_size
1695 COMMENT: size [acl acl...]
1698 DEFAULT_DOC: No limit is applied.
1699 LOC: Config.ReplyBodySize
1701 This option specifies the maximum size of a reply body. It can be
1702 used to prevent users from downloading very large files, such as
1703 MP3's and movies. When the reply headers are received, the
1704 reply_body_max_size lines are processed, and the first line where
1705 all (if any) listed ACLs are true is used as the maximum body size
1708 This size is checked twice. First when we get the reply headers,
1709 we check the content-length value. If the content length value exists
1710 and is larger than the allowed size, the request is denied and the
1711 user receives an error message that says "the request or reply
1712 is too large." If there is no content-length, and the reply
1713 size exceeds this limit, the client's connection is just closed
1714 and they will receive a partial reply.
1716 WARNING: downstream caches probably can not detect a partial reply
1717 if there is no content-length header, so they will cache
1718 partial responses and give them out as hits. You should NOT
1719 use this option if you have downstream caches.
1721 WARNING: A maximum size smaller than the size of squid's error messages
1722 will cause an infinite loop and crash squid. Ensure that the smallest
1723 non-zero value you use is greater that the maximum header size plus
1724 the size of your largest error page.
1726 If you set this parameter none (the default), there will be
1729 Configuration Format is:
1730 reply_body_max_size SIZE UNITS [acl ...]
1732 reply_body_max_size 10 MB
1736 NAME: on_unsupported_protocol
1737 TYPE: on_unsupported_protocol
1738 LOC: Config.accessList.on_unsupported_protocol
1740 DEFAULT_DOC: Respond with an error message to unidentifiable traffic
1742 Determines Squid behavior when encountering strange requests at the
1743 beginning of an accepted TCP connection or the beginning of a bumped
1744 CONNECT tunnel. Controlling Squid reaction to unexpected traffic is
1745 especially useful in interception environments where Squid is likely
1746 to see connections for unsupported protocols that Squid should either
1747 terminate or tunnel at TCP level.
1749 on_unsupported_protocol <action> [!]acl ...
1751 The first matching action wins. Only fast ACLs are supported.
1753 Supported actions are:
1755 tunnel: Establish a TCP connection with the intended server and
1756 blindly shovel TCP packets between the client and server.
1758 respond: Respond with an error message, using the transfer protocol
1759 for the Squid port that received the request (e.g., HTTP
1760 for connections intercepted at the http_port). This is the
1763 Squid expects the following traffic patterns:
1765 http_port: a plain HTTP request
1766 https_port: SSL/TLS handshake followed by an [encrypted] HTTP request
1767 ftp_port: a plain FTP command (no on_unsupported_protocol support yet!)
1768 CONNECT tunnel on http_port: same as https_port
1769 CONNECT tunnel on https_port: same as https_port
1771 Currently, this directive has effect on intercepted connections and
1772 bumped tunnels only. Other cases are not supported because Squid
1773 cannot know the intended destination of other traffic.
1776 # define what Squid errors indicate receiving non-HTTP traffic:
1777 acl foreignProtocol squid_error ERR_PROTOCOL_UNKNOWN ERR_TOO_BIG
1778 # define what Squid errors indicate receiving nothing:
1779 acl serverTalksFirstProtocol squid_error ERR_REQUEST_START_TIMEOUT
1780 # tunnel everything that does not look like HTTP:
1781 on_unsupported_protocol tunnel foreignProtocol
1782 # tunnel if we think the client waits for the server to talk first:
1783 on_unsupported_protocol tunnel serverTalksFirstProtocol
1784 # in all other error cases, just send an HTTP "error page" response:
1785 on_unsupported_protocol respond all
1787 See also: squid_error ACL
1792 -----------------------------------------------------------------------------
1795 NAME: http_port ascii_port
1800 Usage: port [mode] [options]
1801 hostname:port [mode] [options]
1802 1.2.3.4:port [mode] [options]
1804 The socket addresses where Squid will listen for HTTP client
1805 requests. You may specify multiple socket addresses.
1806 There are three forms: port alone, hostname with port, and
1807 IP address with port. If you specify a hostname or IP
1808 address, Squid binds the socket to that specific
1809 address. Most likely, you do not need to bind to a specific
1810 address, so you can use the port number alone.
1812 If you are running Squid in accelerator mode, you
1813 probably want to listen on port 80 also, or instead.
1815 The -a command line option may be used to specify additional
1816 port(s) where Squid listens for proxy request. Such ports will
1817 be plain proxy ports with no options.
1819 You may specify multiple socket addresses on multiple lines.
1823 intercept Support for IP-Layer interception of
1824 outgoing requests without browser settings.
1825 NP: disables authentication and IPv6 on the port.
1827 tproxy Support Linux TPROXY for spoofing outgoing
1828 connections using the client IP address.
1829 NP: disables authentication and maybe IPv6 on the port.
1831 accel Accelerator / reverse proxy mode
1833 ssl-bump For each CONNECT request allowed by ssl_bump ACLs,
1834 establish secure connection with the client and with
1835 the server, decrypt HTTPS messages as they pass through
1836 Squid, and treat them as unencrypted HTTP messages,
1837 becoming the man-in-the-middle.
1839 The ssl_bump option is required to fully enable
1840 bumping of CONNECT requests.
1842 Omitting the mode flag causes default forward proxy mode to be used.
1845 Accelerator Mode Options:
1847 defaultsite=domainname
1848 What to use for the Host: header if it is not present
1849 in a request. Determines what site (not origin server)
1850 accelerators should consider the default.
1852 no-vhost Disable using HTTP/1.1 Host header for virtual domain support.
1854 protocol= Protocol to reconstruct accelerated and intercepted
1855 requests with. Defaults to HTTP/1.1 for http_port and
1856 HTTPS/1.1 for https_port.
1857 When an unsupported value is configured Squid will
1858 produce a FATAL error.
1859 Values: HTTP or HTTP/1.1, HTTPS or HTTPS/1.1
1861 vport Virtual host port support. Using the http_port number
1862 instead of the port passed on Host: headers.
1864 vport=NN Virtual host port support. Using the specified port
1865 number instead of the port passed on Host: headers.
1868 Act as if this Squid is the origin server.
1869 This currently means generate new Date: and Expires:
1870 headers on HIT instead of adding Age:.
1872 ignore-cc Ignore request Cache-Control headers.
1874 WARNING: This option violates HTTP specifications if
1875 used in non-accelerator setups.
1877 allow-direct Allow direct forwarding in accelerator mode. Normally
1878 accelerated requests are denied direct forwarding as if
1879 never_direct was used.
1881 WARNING: this option opens accelerator mode to security
1882 vulnerabilities usually only affecting in interception
1883 mode. Make sure to protect forwarding with suitable
1884 http_access rules when using this.
1887 SSL Bump Mode Options:
1888 In addition to these options ssl-bump requires TLS/SSL options.
1890 generate-host-certificates[=<on|off>]
1891 Dynamically create SSL server certificates for the
1892 destination hosts of bumped CONNECT requests.When
1893 enabled, the cert and key options are used to sign
1894 generated certificates. Otherwise generated
1895 certificate will be selfsigned.
1896 If there is a CA certificate lifetime of the generated
1897 certificate equals lifetime of the CA certificate. If
1898 generated certificate is selfsigned lifetime is three
1900 This option is enabled by default when ssl-bump is used.
1901 See the ssl-bump option above for more information.
1903 dynamic_cert_mem_cache_size=SIZE
1904 Approximate total RAM size spent on cached generated
1905 certificates. If set to zero, caching is disabled. The
1906 default value is 4MB.
1910 cert= Path to SSL certificate (PEM format).
1912 key= Path to SSL private key file (PEM format)
1913 if not specified, the certificate file is
1914 assumed to be a combined certificate and
1917 cipher= Colon separated list of supported ciphers.
1918 NOTE: some ciphers such as EDH ciphers depend on
1919 additional settings. If those settings are
1920 omitted the ciphers may be silently ignored
1921 by the OpenSSL library.
1923 options= Various SSL implementation options. The most important
1926 NO_SSLv3 Disallow the use of SSLv3
1928 NO_TLSv1 Disallow the use of TLSv1.0
1930 NO_TLSv1_1 Disallow the use of TLSv1.1
1932 NO_TLSv1_2 Disallow the use of TLSv1.2
1935 Always create a new key when using
1936 temporary/ephemeral DH key exchanges
1939 Enable ephemeral ECDH key exchange.
1940 The adopted curve should be specified
1941 using the tls-dh option.
1944 Disable use of RFC5077 session tickets.
1945 Some servers may have problems
1946 understanding the TLS extension due
1947 to ambiguous specification in RFC4507.
1949 ALL Enable various bug workarounds
1950 suggested as "harmless" by OpenSSL
1951 Be warned that this reduces SSL/TLS
1952 strength to some attacks.
1954 See the OpenSSL SSL_CTX_set_options documentation for a
1957 clientca= File containing the list of CAs to use when
1958 requesting a client certificate.
1960 cafile= File containing additional CA certificates to
1961 use when verifying client certificates. If unset
1962 clientca will be used.
1964 capath= Directory containing additional CA certificates
1965 and CRL lists to use when verifying client certificates.
1967 crlfile= File of additional CRL lists to use when verifying
1968 the client certificate, in addition to CRLs stored in
1969 the capath. Implies VERIFY_CRL flag below.
1972 File containing DH parameters for temporary/ephemeral DH key
1973 exchanges, optionally prefixed by a curve for ephemeral ECDH
1975 See OpenSSL documentation for details on how to create the
1976 DH parameter file. Supported curves for ECDH can be listed
1977 using the "openssl ecparam -list_curves" command.
1978 WARNING: EDH and EECDH ciphers will be silently disabled if
1979 this option is not set.
1981 sslflags= Various flags modifying the use of SSL:
1983 Don't request client certificates
1984 immediately, but wait until acl processing
1985 requires a certificate (not yet implemented).
1987 Don't use the default CA lists built in
1990 Don't allow for session reuse. Each connection
1991 will result in a new SSL session.
1993 Verify CRL lists when accepting client
1996 Verify CRL lists for all certificates in the
1997 client certificate chain.
1999 sslcontext= SSL session ID context identifier.
2003 connection-auth[=on|off]
2004 use connection-auth=off to tell Squid to prevent
2005 forwarding Microsoft connection oriented authentication
2006 (NTLM, Negotiate and Kerberos)
2008 disable-pmtu-discovery=
2009 Control Path-MTU discovery usage:
2010 off lets OS decide on what to do (default).
2011 transparent disable PMTU discovery when transparent
2013 always disable always PMTU discovery.
2015 In many setups of transparently intercepting proxies
2016 Path-MTU discovery can not work on traffic towards the
2017 clients. This is the case when the intercepting device
2018 does not fully track connections and fails to forward
2019 ICMP must fragment messages to the cache server. If you
2020 have such setup and experience that certain clients
2021 sporadically hang or never complete requests set
2022 disable-pmtu-discovery option to 'transparent'.
2024 name= Specifies a internal name for the port. Defaults to
2025 the port specification (port or addr:port)
2027 tcpkeepalive[=idle,interval,timeout]
2028 Enable TCP keepalive probes of idle connections.
2029 In seconds; idle is the initial time before TCP starts
2030 probing the connection, interval how often to probe, and
2031 timeout the time before giving up.
2033 require-proxy-header
2034 Require PROXY protocol version 1 or 2 connections.
2035 The proxy_protocol_access is required to whitelist
2036 downstream proxies which can be trusted.
2038 If you run Squid on a dual-homed machine with an internal
2039 and an external interface we recommend you to specify the
2040 internal address:port in http_port. This way Squid will only be
2041 visible on the internal address.
2045 # Squid normally listens to port 3128
2046 http_port @DEFAULT_HTTP_PORT@
2056 Usage: [ip:]port cert=certificate.pem [key=key.pem] [mode] [options...]
2058 The socket address where Squid will listen for client requests made
2059 over TLS or SSL connections. Commonly referred to as HTTPS.
2061 This is most useful for situations where you are running squid in
2062 accelerator mode and you want to do the SSL work at the accelerator level.
2064 You may specify multiple socket addresses on multiple lines,
2065 each with their own SSL certificate and/or options.
2069 accel Accelerator / reverse proxy mode
2071 intercept Support for IP-Layer interception of
2072 outgoing requests without browser settings.
2073 NP: disables authentication and IPv6 on the port.
2075 tproxy Support Linux TPROXY for spoofing outgoing
2076 connections using the client IP address.
2077 NP: disables authentication and maybe IPv6 on the port.
2079 ssl-bump For each intercepted connection allowed by ssl_bump
2080 ACLs, establish a secure connection with the client and with
2081 the server, decrypt HTTPS messages as they pass through
2082 Squid, and treat them as unencrypted HTTP messages,
2083 becoming the man-in-the-middle.
2085 An "ssl_bump server-first" match is required to
2086 fully enable bumping of intercepted SSL connections.
2088 Requires tproxy or intercept.
2090 Omitting the mode flag causes default forward proxy mode to be used.
2093 See http_port for a list of generic options
2098 cert= Path to SSL certificate (PEM format).
2100 key= Path to SSL private key file (PEM format)
2101 if not specified, the certificate file is
2102 assumed to be a combined certificate and
2105 cipher= Colon separated list of supported ciphers.
2107 options= Various SSL engine options. The most important
2110 NO_SSLv3 Disallow the use of SSLv3
2112 NO_TLSv1 Disallow the use of TLSv1.0
2114 NO_TLSv1_1 Disallow the use of TLSv1.1
2116 NO_TLSv1_2 Disallow the use of TLSv1.2
2119 Always create a new key when using
2120 temporary/ephemeral DH key exchanges
2123 Enable ephemeral ECDH key exchange.
2124 The adopted curve should be specified
2125 using the tls-dh option.
2128 Disable use of RFC5077 session tickets.
2129 Some servers may have problems
2130 understanding the TLS extension due
2131 to ambiguous specification in RFC4507.
2133 ALL Enable various bug workarounds
2134 suggested as "harmless" by OpenSSL
2135 Be warned that this reduces SSL/TLS
2136 strength to some attacks.
2138 See the OpenSSL SSL_CTX_set_options documentation for a
2141 clientca= File containing the list of CAs to use when
2142 requesting a client certificate.
2144 cafile= File containing additional CA certificates to
2145 use when verifying client certificates. If unset
2146 clientca will be used.
2148 capath= Directory containing additional CA certificates
2149 and CRL lists to use when verifying client certificates.
2151 crlfile= File of additional CRL lists to use when verifying
2152 the client certificate, in addition to CRLs stored in
2153 the capath. Implies VERIFY_CRL flag below.
2156 File containing DH parameters for temporary/ephemeral DH key
2157 exchanges, optionally prefixed by a curve for ephemeral ECDH
2160 sslflags= Various flags modifying the use of SSL:
2162 Don't request client certificates
2163 immediately, but wait until acl processing
2164 requires a certificate (not yet implemented).
2166 Don't use the default CA lists built in
2169 Don't allow for session reuse. Each connection
2170 will result in a new SSL session.
2172 Verify CRL lists when accepting client
2175 Verify CRL lists for all certificates in the
2176 client certificate chain.
2178 sslcontext= SSL session ID context identifier.
2180 generate-host-certificates[=<on|off>]
2181 Dynamically create SSL server certificates for the
2182 destination hosts of bumped SSL requests.When
2183 enabled, the cert and key options are used to sign
2184 generated certificates. Otherwise generated
2185 certificate will be selfsigned.
2186 If there is CA certificate life time of generated
2187 certificate equals lifetime of CA certificate. If
2188 generated certificate is selfsigned lifetime is three
2190 This option is enabled by default when SslBump is used.
2191 See the sslBump option above for more information.
2193 dynamic_cert_mem_cache_size=SIZE
2194 Approximate total RAM size spent on cached generated
2195 certificates. If set to zero, caching is disabled. The
2196 default value is 4MB.
2198 See http_port for a list of available options.
2206 Enables Native FTP proxy by specifying the socket address where Squid
2207 listens for FTP client requests. See http_port directive for various
2208 ways to specify the listening address and mode.
2210 Usage: ftp_port address [mode] [options]
2212 WARNING: This is a new, experimental, complex feature that has seen
2213 limited production exposure. Some Squid modules (e.g., caching) do not
2214 currently work with native FTP proxying, and many features have not
2215 even been tested for compatibility. Test well before deploying!
2217 Native FTP proxying differs substantially from proxying HTTP requests
2218 with ftp:// URIs because Squid works as an FTP server and receives
2219 actual FTP commands (rather than HTTP requests with FTP URLs).
2221 Native FTP commands accepted at ftp_port are internally converted or
2222 wrapped into HTTP-like messages. The same happens to Native FTP
2223 responses received from FTP origin servers. Those HTTP-like messages
2224 are shoveled through regular access control and adaptation layers
2225 between the FTP client and the FTP origin server. This allows Squid to
2226 examine, adapt, block, and log FTP exchanges. Squid reuses most HTTP
2227 mechanisms when shoveling wrapped FTP messages. For example,
2228 http_access and adaptation_access directives are used.
2232 intercept Same as http_port intercept. The FTP origin address is
2233 determined based on the intended destination of the
2234 intercepted connection.
2236 tproxy Support Linux TPROXY for spoofing outgoing
2237 connections using the client IP address.
2238 NP: disables authentication and maybe IPv6 on the port.
2240 By default (i.e., without an explicit mode option), Squid extracts the
2241 FTP origin address from the login@origin parameter of the FTP USER
2242 command. Many popular FTP clients support such native FTP proxying.
2246 name=token Specifies an internal name for the port. Defaults to
2247 the port address. Usable with myportname ACL.
2250 Enables tracking of FTP directories by injecting extra
2251 PWD commands and adjusting Request-URI (in wrapping
2252 HTTP requests) to reflect the current FTP server
2253 directory. Tracking is disabled by default.
2255 protocol=FTP Protocol to reconstruct accelerated and intercepted
2256 requests with. Defaults to FTP. No other accepted
2257 values have been tested with. An unsupported value
2258 results in a FATAL error. Accepted values are FTP,
2259 HTTP (or HTTP/1.1), and HTTPS (or HTTPS/1.1).
2261 Other http_port modes and options that are not specific to HTTP and
2262 HTTPS may also work.
2265 NAME: tcp_outgoing_tos tcp_outgoing_ds tcp_outgoing_dscp
2268 LOC: Ip::Qos::TheConfig.tosToServer
2270 Allows you to select a TOS/Diffserv value for packets outgoing
2271 on the server side, based on an ACL.
2273 tcp_outgoing_tos ds-field [!]aclname ...
2275 Example where normal_service_net uses the TOS value 0x00
2276 and good_service_net uses 0x20
2278 acl normal_service_net src 10.0.0.0/24
2279 acl good_service_net src 10.0.1.0/24
2280 tcp_outgoing_tos 0x00 normal_service_net
2281 tcp_outgoing_tos 0x20 good_service_net
2283 TOS/DSCP values really only have local significance - so you should
2284 know what you're specifying. For more information, see RFC2474,
2285 RFC2475, and RFC3260.
2287 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
2288 "default" to use whatever default your host has.
2289 Note that only multiples of 4 are usable as the two rightmost bits have
2290 been redefined for use by ECN (RFC 3168 section 23.1).
2291 The squid parser will enforce this by masking away the ECN bits.
2293 Processing proceeds in the order specified, and stops at first fully
2296 Only fast ACLs are supported.
2299 NAME: clientside_tos
2302 LOC: Ip::Qos::TheConfig.tosToClient
2304 Allows you to select a TOS/DSCP value for packets being transmitted
2305 on the client-side, based on an ACL.
2307 clientside_tos ds-field [!]aclname ...
2309 Example where normal_service_net uses the TOS value 0x00
2310 and good_service_net uses 0x20
2312 acl normal_service_net src 10.0.0.0/24
2313 acl good_service_net src 10.0.1.0/24
2314 clientside_tos 0x00 normal_service_net
2315 clientside_tos 0x20 good_service_net
2317 Note: This feature is incompatible with qos_flows. Any TOS values set here
2318 will be overwritten by TOS values in qos_flows.
2320 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
2321 "default" to use whatever default your host has.
2322 Note that only multiples of 4 are usable as the two rightmost bits have
2323 been redefined for use by ECN (RFC 3168 section 23.1).
2324 The squid parser will enforce this by masking away the ECN bits.
2328 NAME: tcp_outgoing_mark
2330 IFDEF: SO_MARK&&USE_LIBCAP
2332 LOC: Ip::Qos::TheConfig.nfmarkToServer
2334 Allows you to apply a Netfilter mark value to outgoing packets
2335 on the server side, based on an ACL.
2337 tcp_outgoing_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 tcp_outgoing_mark 0x00 normal_service_net
2345 tcp_outgoing_mark 0x20 good_service_net
2347 Only fast ACLs are supported.
2350 NAME: clientside_mark
2352 IFDEF: SO_MARK&&USE_LIBCAP
2354 LOC: Ip::Qos::TheConfig.nfmarkToClient
2356 Allows you to apply a Netfilter mark value to packets being transmitted
2357 on the client-side, based on an ACL.
2359 clientside_mark mark-value [!]aclname ...
2361 Example where normal_service_net uses the mark value 0x00
2362 and good_service_net uses 0x20
2364 acl normal_service_net src 10.0.0.0/24
2365 acl good_service_net src 10.0.1.0/24
2366 clientside_mark 0x00 normal_service_net
2367 clientside_mark 0x20 good_service_net
2369 Note: This feature is incompatible with qos_flows. Any mark values set here
2370 will be overwritten by mark values in qos_flows.
2377 LOC: Ip::Qos::TheConfig
2379 Allows you to select a TOS/DSCP value to mark outgoing
2380 connections to the client, based on where the reply was sourced.
2381 For platforms using netfilter, allows you to set a netfilter mark
2382 value instead of, or in addition to, a TOS value.
2384 By default this functionality is disabled. To enable it with the default
2385 settings simply use "qos_flows mark" or "qos_flows tos". Default
2386 settings will result in the netfilter mark or TOS value being copied
2387 from the upstream connection to the client. Note that it is the connection
2388 CONNMARK value not the packet MARK value that is copied.
2390 It is not currently possible to copy the mark or TOS value from the
2391 client to the upstream connection request.
2393 TOS values really only have local significance - so you should
2394 know what you're specifying. For more information, see RFC2474,
2395 RFC2475, and RFC3260.
2397 The TOS/DSCP byte must be exactly that - a octet value 0 - 255.
2398 Note that only multiples of 4 are usable as the two rightmost bits have
2399 been redefined for use by ECN (RFC 3168 section 23.1).
2400 The squid parser will enforce this by masking away the ECN bits.
2402 Mark values can be any unsigned 32-bit integer value.
2404 This setting is configured by setting the following values:
2406 tos|mark Whether to set TOS or netfilter mark values
2408 local-hit=0xFF Value to mark local cache hits.
2410 sibling-hit=0xFF Value to mark hits from sibling peers.
2412 parent-hit=0xFF Value to mark hits from parent peers.
2414 miss=0xFF[/mask] Value to mark cache misses. Takes precedence
2415 over the preserve-miss feature (see below), unless
2416 mask is specified, in which case only the bits
2417 specified in the mask are written.
2419 The TOS variant of the following features are only possible on Linux
2420 and require your kernel to be patched with the TOS preserving ZPH
2421 patch, available from http://zph.bratcheda.org
2422 No patch is needed to preserve the netfilter mark, which will work
2423 with all variants of netfilter.
2425 disable-preserve-miss
2426 This option disables the preservation of the TOS or netfilter
2427 mark. By default, the existing TOS or netfilter mark value of
2428 the response coming from the remote server will be retained
2429 and masked with miss-mark.
2430 NOTE: in the case of a netfilter mark, the mark must be set on
2431 the connection (using the CONNMARK target) not on the packet
2435 Allows you to mask certain bits in the TOS or mark value
2436 received from the remote server, before copying the value to
2437 the TOS sent towards clients.
2438 Default for tos: 0xFF (TOS from server is not changed).
2439 Default for mark: 0xFFFFFFFF (mark from server is not changed).
2441 All of these features require the --enable-zph-qos compilation flag
2442 (enabled by default). Netfilter marking also requires the
2443 libnetfilter_conntrack libraries (--with-netfilter-conntrack) and
2444 libcap 2.09+ (--with-libcap).
2448 NAME: tcp_outgoing_address
2451 DEFAULT_DOC: Address selection is performed by the operating system.
2452 LOC: Config.accessList.outgoing_address
2454 Allows you to map requests to different outgoing IP addresses
2455 based on the username or source address of the user making
2458 tcp_outgoing_address ipaddr [[!]aclname] ...
2461 Forwarding clients with dedicated IPs for certain subnets.
2463 acl normal_service_net src 10.0.0.0/24
2464 acl good_service_net src 10.0.2.0/24
2466 tcp_outgoing_address 2001:db8::c001 good_service_net
2467 tcp_outgoing_address 10.1.0.2 good_service_net
2469 tcp_outgoing_address 2001:db8::beef normal_service_net
2470 tcp_outgoing_address 10.1.0.1 normal_service_net
2472 tcp_outgoing_address 2001:db8::1
2473 tcp_outgoing_address 10.1.0.3
2475 Processing proceeds in the order specified, and stops at first fully
2478 Squid will add an implicit IP version test to each line.
2479 Requests going to IPv4 websites will use the outgoing 10.1.0.* addresses.
2480 Requests going to IPv6 websites will use the outgoing 2001:db8:* addresses.
2483 NOTE: The use of this directive using client dependent ACLs is
2484 incompatible with the use of server side persistent connections. To
2485 ensure correct results it is best to set server_persistent_connections
2486 to off when using this directive in such configurations.
2488 NOTE: The use of this directive to set a local IP on outgoing TCP links
2489 is incompatible with using TPROXY to set client IP out outbound TCP links.
2490 When needing to contact peers use the no-tproxy cache_peer option and the
2491 client_dst_passthru directive re-enable normal forwarding such as this.
2495 NAME: host_verify_strict
2498 LOC: Config.onoff.hostStrictVerify
2500 Regardless of this option setting, when dealing with intercepted
2501 traffic, Squid always verifies that the destination IP address matches
2502 the Host header domain or IP (called 'authority form URL').
2504 This enforcement is performed to satisfy a MUST-level requirement in
2505 RFC 2616 section 14.23: "The Host field value MUST represent the naming
2506 authority of the origin server or gateway given by the original URL".
2509 Squid always responds with an HTTP 409 (Conflict) error
2510 page and logs a security warning if there is no match.
2512 Squid verifies that the destination IP address matches
2513 the Host header for forward-proxy and reverse-proxy traffic
2514 as well. For those traffic types, Squid also enables the
2515 following checks, comparing the corresponding Host header
2516 and Request-URI components:
2518 * The host names (domain or IP) must be identical,
2519 but valueless or missing Host header disables all checks.
2520 For the two host names to match, both must be either IP
2523 * Port numbers must be identical, but if a port is missing
2524 the scheme-default port is assumed.
2527 When set to OFF (the default):
2528 Squid allows suspicious requests to continue but logs a
2529 security warning and blocks caching of the response.
2531 * Forward-proxy traffic is not checked at all.
2533 * Reverse-proxy traffic is not checked at all.
2535 * Intercepted traffic which passes verification is handled
2536 according to client_dst_passthru.
2538 * Intercepted requests which fail verification are sent
2539 to the client original destination instead of DIRECT.
2540 This overrides 'client_dst_passthru off'.
2542 For now suspicious intercepted CONNECT requests are always
2543 responded to with an HTTP 409 (Conflict) error page.
2548 As described in CVE-2009-0801 when the Host: header alone is used
2549 to determine the destination of a request it becomes trivial for
2550 malicious scripts on remote websites to bypass browser same-origin
2551 security policy and sandboxing protections.
2553 The cause of this is that such applets are allowed to perform their
2554 own HTTP stack, in which case the same-origin policy of the browser
2555 sandbox only verifies that the applet tries to contact the same IP
2556 as from where it was loaded at the IP level. The Host: header may
2557 be different from the connected IP and approved origin.
2561 NAME: client_dst_passthru
2564 LOC: Config.onoff.client_dst_passthru
2566 With NAT or TPROXY intercepted traffic Squid may pass the request
2567 directly to the original client destination IP or seek a faster
2568 source using the HTTP Host header.
2570 Using Host to locate alternative servers can provide faster
2571 connectivity with a range of failure recovery options.
2572 But can also lead to connectivity trouble when the client and
2573 server are attempting stateful interactions unaware of the proxy.
2575 This option (on by default) prevents alternative DNS entries being
2576 located to send intercepted traffic DIRECT to an origin server.
2577 The clients original destination IP and port will be used instead.
2579 Regardless of this option setting, when dealing with intercepted
2580 traffic Squid will verify the Host: header and any traffic which
2581 fails Host verification will be treated as if this option were ON.
2583 see host_verify_strict for details on the verification process.
2588 -----------------------------------------------------------------------------
2591 NAME: tls_outgoing_options
2592 IFDEF: USE_GNUTLS||USE_OPENSSL
2593 TYPE: securePeerOptions
2594 DEFAULT: min-version=1.0
2595 LOC: Security::ProxyOutgoingConfig
2597 disable Do not support https:// URLs.
2599 cert=/path/to/client/certificate
2600 A client TLS certificate to use when connecting.
2602 key=/path/to/client/private_key
2603 The private TLS key corresponding to the cert= above.
2604 If key= is not specified cert= is assumed to reference
2605 a PEM file containing both the certificate and the key.
2607 cipher=... The list of valid TLS ciphers to use.
2610 The minimum TLS protocol version to permit.
2611 To control SSLv3 use the options= parameter.
2612 Supported Values: 1.0 (default), 1.1, 1.2
2614 options=... Specify various TLS/SSL implementation options:
2616 NO_SSLv3 Disallow the use of SSLv3
2618 NO_TLSv1 Disallow the use of TLSv1.0
2620 NO_TLSv1_1 Disallow the use of TLSv1.1
2622 NO_TLSv1_2 Disallow the use of TLSv1.2
2625 Always create a new key when using
2626 temporary/ephemeral DH key exchanges
2629 Disable use of RFC5077 session tickets.
2630 Some servers may have problems
2631 understanding the TLS extension due
2632 to ambiguous specification in RFC4507.
2634 ALL Enable various bug workarounds
2635 suggested as "harmless" by OpenSSL
2636 Be warned that this reduces SSL/TLS
2637 strength to some attacks.
2639 See the OpenSSL SSL_CTX_set_options documentation for a
2642 cafile=... A file containing additional CA certificates to use
2643 when verifying the peer certificate.
2645 capath=... A directory containing additional CA certificates to
2646 use when verifying the peer certificate.
2648 crlfile=... A certificate revocation list file to use when
2649 verifying the peer certificate.
2651 flags=... Specify various flags modifying the TLS implementation:
2654 Accept certificates even if they fail to
2657 Don't use the default CA list built in
2660 Don't verify the peer certificate
2661 matches the server name
2663 domain= The peer name as advertised in its certificate.
2664 Used for verifying the correctness of the received peer
2665 certificate. If not specified the peer hostname will be
2671 -----------------------------------------------------------------------------
2674 NAME: ssl_unclean_shutdown
2678 LOC: Config.SSL.unclean_shutdown
2680 Some browsers (especially MSIE) bugs out on SSL shutdown
2687 LOC: Config.SSL.ssl_engine
2690 The OpenSSL engine to use. You will need to set this if you
2691 would like to use hardware SSL acceleration for example.
2694 NAME: sslproxy_session_ttl
2697 LOC: Config.SSL.session_ttl
2700 Sets the timeout value for SSL sessions
2703 NAME: sslproxy_session_cache_size
2706 LOC: Config.SSL.sessionCacheSize
2709 Sets the cache size to use for ssl session
2712 NAME: sslproxy_cert_sign_hash
2715 LOC: Config.SSL.certSignHash
2718 Sets the hashing algorithm to use when signing generated certificates.
2719 Valid algorithm names depend on the OpenSSL library used. The following
2720 names are usually available: sha1, sha256, sha512, and md5. Please see
2721 your OpenSSL library manual for the available hashes. By default, Squids
2722 that support this option use sha256 hashes.
2724 Squid does not forcefully purge cached certificates that were generated
2725 with an algorithm other than the currently configured one. They remain
2726 in the cache, subject to the regular cache eviction policy, and become
2727 useful if the algorithm changes again.
2732 TYPE: sslproxy_ssl_bump
2733 LOC: Config.accessList.ssl_bump
2734 DEFAULT_DOC: Become a TCP tunnel without decrypting proxied traffic.
2737 This option is consulted when a CONNECT request is received on
2738 an http_port (or a new connection is intercepted at an
2739 https_port), provided that port was configured with an ssl-bump
2740 flag. The subsequent data on the connection is either treated as
2741 HTTPS and decrypted OR tunneled at TCP level without decryption,
2742 depending on the first matching bumping "action".
2744 ssl_bump <action> [!]acl ...
2746 The following bumping actions are currently supported:
2749 Become a TCP tunnel without decrypting proxied traffic.
2750 This is the default action.
2753 Establish a secure connection with the server and, using a
2754 mimicked server certificate, with the client.
2757 Receive client (step SslBump1) or server (step SslBump2)
2758 certificate while preserving the possibility of splicing the
2759 connection. Peeking at the server certificate (during step 2)
2760 usually precludes bumping of the connection at step 3.
2763 Receive client (step SslBump1) or server (step SslBump2)
2764 certificate while preserving the possibility of bumping the
2765 connection. Staring at the server certificate (during step 2)
2766 usually precludes splicing of the connection at step 3.
2769 Close client and server connections.
2771 Backward compatibility actions available at step SslBump1:
2774 Bump the connection. Establish a secure connection with the
2775 client first, then connect to the server. This old mode does
2776 not allow Squid to mimic server SSL certificate and does not
2777 work with intercepted SSL connections.
2780 Bump the connection. Establish a secure connection with the
2781 server first, then establish a secure connection with the
2782 client, using a mimicked server certificate. Works with both
2783 CONNECT requests and intercepted SSL connections, but does
2784 not allow to make decisions based on SSL handshake info.
2787 Decide whether to bump or splice the connection based on
2788 client-to-squid and server-to-squid SSL hello messages.
2792 Same as the "splice" action.
2794 All ssl_bump rules are evaluated at each of the supported bumping
2795 steps. Rules with actions that are impossible at the current step are
2796 ignored. The first matching ssl_bump action wins and is applied at the
2797 end of the current step. If no rules match, the splice action is used.
2798 See the at_step ACL for a list of the supported SslBump steps.
2800 This clause supports both fast and slow acl types.
2801 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2803 See also: http_port ssl-bump, https_port ssl-bump, and acl at_step.
2806 # Example: Bump all requests except those originating from
2807 # localhost or those going to example.com.
2809 acl broken_sites dstdomain .example.com
2810 ssl_bump splice localhost
2811 ssl_bump splice broken_sites
2815 NAME: sslproxy_cert_error
2818 DEFAULT_DOC: Server certificate errors terminate the transaction.
2819 LOC: Config.ssl_client.cert_error
2822 Use this ACL to bypass server certificate validation errors.
2824 For example, the following lines will bypass all validation errors
2825 when talking to servers for example.com. All other
2826 validation errors will result in ERR_SECURE_CONNECT_FAIL error.
2828 acl BrokenButTrustedServers dstdomain example.com
2829 sslproxy_cert_error allow BrokenButTrustedServers
2830 sslproxy_cert_error deny all
2832 This clause only supports fast acl types.
2833 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2834 Using slow acl types may result in server crashes
2836 Without this option, all server certificate validation errors
2837 terminate the transaction to protect Squid and the client.
2839 SQUID_X509_V_ERR_INFINITE_VALIDATION error cannot be bypassed
2840 but should not happen unless your OpenSSL library is buggy.
2843 Bypassing validation errors is dangerous because an
2844 error usually implies that the server cannot be trusted
2845 and the connection may be insecure.
2847 See also: sslproxy_flags and DONT_VERIFY_PEER.
2850 NAME: sslproxy_cert_sign
2853 POSTSCRIPTUM: signUntrusted ssl::certUntrusted
2854 POSTSCRIPTUM: signSelf ssl::certSelfSigned
2855 POSTSCRIPTUM: signTrusted all
2856 TYPE: sslproxy_cert_sign
2857 LOC: Config.ssl_client.cert_sign
2860 sslproxy_cert_sign <signing algorithm> acl ...
2862 The following certificate signing algorithms are supported:
2865 Sign using the configured CA certificate which is usually
2866 placed in and trusted by end-user browsers. This is the
2867 default for trusted origin server certificates.
2870 Sign to guarantee an X509_V_ERR_CERT_UNTRUSTED browser error.
2871 This is the default for untrusted origin server certificates
2872 that are not self-signed (see ssl::certUntrusted).
2875 Sign using a self-signed certificate with the right CN to
2876 generate a X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT error in the
2877 browser. This is the default for self-signed origin server
2878 certificates (see ssl::certSelfSigned).
2880 This clause only supports fast acl types.
2882 When sslproxy_cert_sign acl(s) match, Squid uses the corresponding
2883 signing algorithm to generate the certificate and ignores all
2884 subsequent sslproxy_cert_sign options (the first match wins). If no
2885 acl(s) match, the default signing algorithm is determined by errors
2886 detected when obtaining and validating the origin server certificate.
2888 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2889 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2890 CONNECT request that carries a domain name. In all other cases (CONNECT
2891 to an IP address or an intercepted SSL connection), Squid cannot detect
2892 the domain mismatch at certificate generation time when
2893 bump-server-first is used.
2896 NAME: sslproxy_cert_adapt
2899 TYPE: sslproxy_cert_adapt
2900 LOC: Config.ssl_client.cert_adapt
2903 sslproxy_cert_adapt <adaptation algorithm> acl ...
2905 The following certificate adaptation algorithms are supported:
2908 Sets the "Not After" property to the "Not After" property of
2909 the CA certificate used to sign generated certificates.
2912 Sets the "Not Before" property to the "Not Before" property of
2913 the CA certificate used to sign generated certificates.
2915 setCommonName or setCommonName{CN}
2916 Sets Subject.CN property to the host name specified as a
2917 CN parameter or, if no explicit CN parameter was specified,
2918 extracted from the CONNECT request. It is a misconfiguration
2919 to use setCommonName without an explicit parameter for
2920 intercepted or tproxied SSL connections.
2922 This clause only supports fast acl types.
2924 Squid first groups sslproxy_cert_adapt options by adaptation algorithm.
2925 Within a group, when sslproxy_cert_adapt acl(s) match, Squid uses the
2926 corresponding adaptation algorithm to generate the certificate and
2927 ignores all subsequent sslproxy_cert_adapt options in that algorithm's
2928 group (i.e., the first match wins within each algorithm group). If no
2929 acl(s) match, the default mimicking action takes place.
2931 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2932 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2933 CONNECT request that carries a domain name. In all other cases (CONNECT
2934 to an IP address or an intercepted SSL connection), Squid cannot detect
2935 the domain mismatch at certificate generation time when
2936 bump-server-first is used.
2939 NAME: sslpassword_program
2942 LOC: Config.Program.ssl_password
2945 Specify a program used for entering SSL key passphrases
2946 when using encrypted SSL certificate keys. If not specified
2947 keys must either be unencrypted, or Squid started with the -N
2948 option to allow it to query interactively for the passphrase.
2950 The key file name is given as argument to the program allowing
2951 selection of the right password if you have multiple encrypted
2956 OPTIONS RELATING TO EXTERNAL SSL_CRTD
2957 -----------------------------------------------------------------------------
2960 NAME: sslcrtd_program
2963 DEFAULT: @DEFAULT_SSL_CRTD@ -s @DEFAULT_SSL_DB_DIR@ -M 4MB
2964 LOC: Ssl::TheConfig.ssl_crtd
2966 Specify the location and options of the executable for ssl_crtd process.
2967 @DEFAULT_SSL_CRTD@ program requires -s and -M parameters
2968 For more information use:
2969 @DEFAULT_SSL_CRTD@ -h
2972 NAME: sslcrtd_children
2973 TYPE: HelperChildConfig
2975 DEFAULT: 32 startup=5 idle=1
2976 LOC: Ssl::TheConfig.ssl_crtdChildren
2978 The maximum number of processes spawn to service ssl server.
2979 The maximum this may be safely set to is 32.
2981 The startup= and idle= options allow some measure of skew in your
2986 Sets the minimum number of processes to spawn when Squid
2987 starts or reconfigures. When set to zero the first request will
2988 cause spawning of the first child process to handle it.
2990 Starting too few children temporary slows Squid under load while it
2991 tries to spawn enough additional processes to cope with traffic.
2995 Sets a minimum of how many processes Squid is to try and keep available
2996 at all times. When traffic begins to rise above what the existing
2997 processes can handle this many more will be spawned up to the maximum
2998 configured. A minimum setting of 1 is required.
3002 Sets the maximum number of queued requests.
3003 If the queued requests exceed queue size for more than 3 minutes
3004 squid aborts its operation.
3005 The default value is set to 2*numberofchildren.
3007 You must have at least one ssl_crtd process.
3010 NAME: sslcrtvalidator_program
3014 LOC: Ssl::TheConfig.ssl_crt_validator
3016 Specify the location and options of the executable for ssl_crt_validator
3019 Usage: sslcrtvalidator_program [ttl=n] [cache=n] path ...
3022 ttl=n TTL in seconds for cached results. The default is 60 secs
3023 cache=n limit the result cache size. The default value is 2048
3026 NAME: sslcrtvalidator_children
3027 TYPE: HelperChildConfig
3029 DEFAULT: 32 startup=5 idle=1 concurrency=1
3030 LOC: Ssl::TheConfig.ssl_crt_validator_Children
3032 The maximum number of processes spawn to service SSL server.
3033 The maximum this may be safely set to is 32.
3035 The startup= and idle= options allow some measure of skew in your
3040 Sets the minimum number of processes to spawn when Squid
3041 starts or reconfigures. When set to zero the first request will
3042 cause spawning of the first child process to handle it.
3044 Starting too few children temporary slows Squid under load while it
3045 tries to spawn enough additional processes to cope with traffic.
3049 Sets a minimum of how many processes Squid is to try and keep available
3050 at all times. When traffic begins to rise above what the existing
3051 processes can handle this many more will be spawned up to the maximum
3052 configured. A minimum setting of 1 is required.
3056 The number of requests each certificate validator helper can handle in
3057 parallel. A value of 0 indicates the certficate validator does not
3058 support concurrency. Defaults to 1.
3060 When this directive is set to a value >= 1 then the protocol
3061 used to communicate with the helper is modified to include
3062 a request ID in front of the request/response. The request
3063 ID from the request must be echoed back with the response
3068 Sets the maximum number of queued requests.
3069 If the queued requests exceed queue size for more than 3 minutes
3070 squid aborts its operation.
3071 The default value is set to 2*numberofchildren.
3073 You must have at least one ssl_crt_validator process.
3077 OPTIONS WHICH AFFECT THE NEIGHBOR SELECTION ALGORITHM
3078 -----------------------------------------------------------------------------
3086 To specify other caches in a hierarchy, use the format:
3088 cache_peer hostname type http-port icp-port [options]
3093 # hostname type port port options
3094 # -------------------- -------- ----- ----- -----------
3095 cache_peer parent.foo.net parent 3128 3130 default
3096 cache_peer sib1.foo.net sibling 3128 3130 proxy-only
3097 cache_peer sib2.foo.net sibling 3128 3130 proxy-only
3098 cache_peer example.com parent 80 0 default
3099 cache_peer cdn.example.com sibling 3128 0
3101 type: either 'parent', 'sibling', or 'multicast'.
3103 proxy-port: The port number where the peer accept HTTP requests.
3104 For other Squid proxies this is usually 3128
3105 For web servers this is usually 80
3107 icp-port: Used for querying neighbor caches about objects.
3108 Set to 0 if the peer does not support ICP or HTCP.
3109 See ICP and HTCP options below for additional details.
3112 ==== ICP OPTIONS ====
3114 You MUST also set icp_port and icp_access explicitly when using these options.
3115 The defaults will prevent peer traffic using ICP.
3118 no-query Disable ICP queries to this neighbor.
3121 Indicates the named peer is a member of a multicast group.
3122 ICP queries will not be sent directly to the peer, but ICP
3123 replies will be accepted from it.
3125 closest-only Indicates that, for ICP_OP_MISS replies, we'll only forward
3126 CLOSEST_PARENT_MISSes and never FIRST_PARENT_MISSes.
3129 To only send ICP queries to this neighbor infrequently.
3130 This is used to keep the neighbor round trip time updated
3131 and is usually used in conjunction with weighted-round-robin.
3134 ==== HTCP OPTIONS ====
3136 You MUST also set htcp_port and htcp_access explicitly when using these options.
3137 The defaults will prevent peer traffic using HTCP.
3140 htcp Send HTCP, instead of ICP, queries to the neighbor.
3141 You probably also want to set the "icp-port" to 4827
3142 instead of 3130. This directive accepts a comma separated
3143 list of options described below.
3145 htcp=oldsquid Send HTCP to old Squid versions (2.5 or earlier).
3147 htcp=no-clr Send HTCP to the neighbor but without
3148 sending any CLR requests. This cannot be used with
3151 htcp=only-clr Send HTCP to the neighbor but ONLY CLR requests.
3152 This cannot be used with no-clr.
3155 Send HTCP to the neighbor including CLRs but only when
3156 they do not result from PURGE requests.
3159 Forward any HTCP CLR requests this proxy receives to the peer.
3162 ==== PEER SELECTION METHODS ====
3164 The default peer selection method is ICP, with the first responding peer
3165 being used as source. These options can be used for better load balancing.
3168 default This is a parent cache which can be used as a "last-resort"
3169 if a peer cannot be located by any of the peer-selection methods.
3170 If specified more than once, only the first is used.
3172 round-robin Load-Balance parents which should be used in a round-robin
3173 fashion in the absence of any ICP queries.
3174 weight=N can be used to add bias.
3176 weighted-round-robin
3177 Load-Balance parents which should be used in a round-robin
3178 fashion with the frequency of each parent being based on the
3179 round trip time. Closer parents are used more often.
3180 Usually used for background-ping parents.
3181 weight=N can be used to add bias.
3183 carp Load-Balance parents which should be used as a CARP array.
3184 The requests will be distributed among the parents based on the
3185 CARP load balancing hash function based on their weight.
3187 userhash Load-balance parents based on the client proxy_auth or ident username.
3189 sourcehash Load-balance parents based on the client source IP.
3192 To be used only for cache peers of type "multicast".
3193 ALL members of this multicast group have "sibling"
3194 relationship with it, not "parent". This is to a multicast
3195 group when the requested object would be fetched only from
3196 a "parent" cache, anyway. It's useful, e.g., when
3197 configuring a pool of redundant Squid proxies, being
3198 members of the same multicast group.
3201 ==== PEER SELECTION OPTIONS ====
3203 weight=N use to affect the selection of a peer during any weighted
3204 peer-selection mechanisms.
3205 The weight must be an integer; default is 1,
3206 larger weights are favored more.
3207 This option does not affect parent selection if a peering
3208 protocol is not in use.
3210 basetime=N Specify a base amount to be subtracted from round trip
3212 It is subtracted before division by weight in calculating
3213 which parent to fectch from. If the rtt is less than the
3214 base time the rtt is set to a minimal value.
3216 ttl=N Specify a TTL to use when sending multicast ICP queries
3218 Only useful when sending to a multicast group.
3219 Because we don't accept ICP replies from random
3220 hosts, you must configure other group members as
3221 peers with the 'multicast-responder' option.
3223 no-delay To prevent access to this neighbor from influencing the
3226 digest-url=URL Tell Squid to fetch the cache digest (if digests are
3227 enabled) for this host from the specified URL rather
3228 than the Squid default location.
3231 ==== CARP OPTIONS ====
3233 carp-key=key-specification
3234 use a different key than the full URL to hash against the peer.
3235 the key-specification is a comma-separated list of the keywords
3236 scheme, host, port, path, params
3237 Order is not important.
3239 ==== ACCELERATOR / REVERSE-PROXY OPTIONS ====
3241 originserver Causes this parent to be contacted as an origin server.
3242 Meant to be used in accelerator setups when the peer
3246 Set the Host header of requests forwarded to this peer.
3247 Useful in accelerator setups where the server (peer)
3248 expects a certain domain name but clients may request
3249 others. ie example.com or www.example.com
3251 no-digest Disable request of cache digests.
3254 Disables requesting ICMP RTT database (NetDB).
3257 ==== AUTHENTICATION OPTIONS ====
3260 If this is a personal/workgroup proxy and your parent
3261 requires proxy authentication.
3263 Note: The string can include URL escapes (i.e. %20 for
3264 spaces). This also means % must be written as %%.
3267 Send login details received from client to this peer.
3268 Both Proxy- and WWW-Authorization headers are passed
3269 without alteration to the peer.
3270 Authentication is not required by Squid for this to work.
3272 Note: This will pass any form of authentication but
3273 only Basic auth will work through a proxy unless the
3274 connection-auth options are also used.
3276 login=PASS Send login details received from client to this peer.
3277 Authentication is not required by this option.
3279 If there are no client-provided authentication headers
3280 to pass on, but username and password are available
3281 from an external ACL user= and password= result tags
3282 they may be sent instead.
3284 Note: To combine this with proxy_auth both proxies must
3285 share the same user database as HTTP only allows for
3286 a single login (one for proxy, one for origin server).
3287 Also be warned this will expose your users proxy
3288 password to the peer. USE WITH CAUTION
3291 Send the username to the upstream cache, but with a
3292 fixed password. This is meant to be used when the peer
3293 is in another administrative domain, but it is still
3294 needed to identify each user.
3295 The star can optionally be followed by some extra
3296 information which is added to the username. This can
3297 be used to identify this proxy to the peer, similar to
3298 the login=username:password option above.
3301 If this is a personal/workgroup proxy and your parent
3302 requires a secure proxy authentication.
3303 The first principal from the default keytab or defined by
3304 the environment variable KRB5_KTNAME will be used.
3306 WARNING: The connection may transmit requests from multiple
3307 clients. Negotiate often assumes end-to-end authentication
3308 and a single-client. Which is not strictly true here.
3310 login=NEGOTIATE:principal_name
3311 If this is a personal/workgroup proxy and your parent
3312 requires a secure proxy authentication.
3313 The principal principal_name from the default keytab or
3314 defined by the environment variable KRB5_KTNAME will be
3317 WARNING: The connection may transmit requests from multiple
3318 clients. Negotiate often assumes end-to-end authentication
3319 and a single-client. Which is not strictly true here.
3321 connection-auth=on|off
3322 Tell Squid that this peer does or not support Microsoft
3323 connection oriented authentication, and any such
3324 challenges received from there should be ignored.
3325 Default is auto to automatically determine the status
3329 ==== SSL / HTTPS / TLS OPTIONS ====
3331 ssl Encrypt connections to this peer with SSL/TLS.
3333 sslcert=/path/to/ssl/certificate
3334 A client SSL certificate to use when connecting to
3337 sslkey=/path/to/ssl/key
3338 The private SSL key corresponding to sslcert above.
3339 If 'sslkey' is not specified 'sslcert' is assumed to
3340 reference a combined file containing both the
3341 certificate and the key.
3343 sslcipher=... The list of valid SSL ciphers to use when connecting
3347 The minimum TLS protocol version to permit. To control
3348 SSLv3 use the ssloptions= parameter.
3349 Supported Values: 1.0 (default), 1.1, 1.2
3351 ssloptions=... Specify various SSL implementation options:
3353 NO_SSLv3 Disallow the use of SSLv3
3355 NO_TLSv1 Disallow the use of TLSv1.0
3357 NO_TLSv1_1 Disallow the use of TLSv1.1
3359 NO_TLSv1_2 Disallow the use of TLSv1.2
3362 Always create a new key when using
3363 temporary/ephemeral DH key exchanges
3366 Disable use of RFC5077 session tickets.
3367 Some servers may have problems
3368 understanding the TLS extension due
3369 to ambiguous specification in RFC4507.
3371 ALL Enable various bug workarounds
3372 suggested as "harmless" by OpenSSL
3373 Be warned that this reduces SSL/TLS
3374 strength to some attacks.
3376 See the OpenSSL SSL_CTX_set_options documentation for a
3379 sslcafile=... A file containing additional CA certificates to use
3380 when verifying the peer certificate.
3382 sslcapath=... A directory containing additional CA certificates to
3383 use when verifying the peer certificate.
3385 sslcrlfile=... A certificate revocation list file to use when
3386 verifying the peer certificate.
3388 sslflags=... Specify various flags modifying the SSL implementation:
3391 Accept certificates even if they fail to
3395 Don't use the default CA list built in
3399 Don't verify the peer certificate
3400 matches the server name
3402 ssldomain= The peer name as advertised in it's certificate.
3403 Used for verifying the correctness of the received peer
3404 certificate. If not specified the peer hostname will be
3408 Enable the "Front-End-Https: On" header needed when
3409 using Squid as a SSL frontend in front of Microsoft OWA.
3410 See MS KB document Q307347 for details on this header.
3411 If set to auto the header will only be added if the
3412 request is forwarded as a https:// URL.
3415 ==== GENERAL OPTIONS ====
3418 A peer-specific connect timeout.
3419 Also see the peer_connect_timeout directive.
3421 connect-fail-limit=N
3422 How many times connecting to a peer must fail before
3423 it is marked as down. Standby connection failures
3424 count towards this limit. Default is 10.
3426 allow-miss Disable Squid's use of only-if-cached when forwarding
3427 requests to siblings. This is primarily useful when
3428 icp_hit_stale is used by the sibling. To extensive use
3429 of this option may result in forwarding loops, and you
3430 should avoid having two-way peerings with this option.
3431 For example to deny peer usage on requests from peer
3432 by denying cache_peer_access if the source is a peer.
3434 max-conn=N Limit the number of concurrent connections the Squid
3435 may open to this peer, including already opened idle
3436 and standby connections. There is no peer-specific
3437 connection limit by default.
3439 A peer exceeding the limit is not used for new
3440 requests unless a standby connection is available.
3442 max-conn currently works poorly with idle persistent
3443 connections: When a peer reaches its max-conn limit,
3444 and there are idle persistent connections to the peer,
3445 the peer may not be selected because the limiting code
3446 does not know whether Squid can reuse those idle
3449 standby=N Maintain a pool of N "hot standby" connections to an
3450 UP peer, available for requests when no idle
3451 persistent connection is available (or safe) to use.
3452 By default and with zero N, no such pool is maintained.
3453 N must not exceed the max-conn limit (if any).
3455 At start or after reconfiguration, Squid opens new TCP
3456 standby connections until there are N connections
3457 available and then replenishes the standby pool as
3458 opened connections are used up for requests. A used
3459 connection never goes back to the standby pool, but
3460 may go to the regular idle persistent connection pool
3461 shared by all peers and origin servers.
3463 Squid never opens multiple new standby connections
3464 concurrently. This one-at-a-time approach minimizes
3465 flooding-like effect on peers. Furthermore, just a few
3466 standby connections should be sufficient in most cases
3467 to supply most new requests with a ready-to-use
3470 Standby connections obey server_idle_pconn_timeout.
3471 For the feature to work as intended, the peer must be
3472 configured to accept and keep them open longer than
3473 the idle timeout at the connecting Squid, to minimize
3474 race conditions typical to idle used persistent
3475 connections. Default request_timeout and
3476 server_idle_pconn_timeout values ensure such a
3479 name=xxx Unique name for the peer.
3480 Required if you have multiple peers on the same host
3481 but different ports.
3482 This name can be used in cache_peer_access and similar
3483 directives to dentify the peer.
3484 Can be used by outgoing access controls through the
3487 no-tproxy Do not use the client-spoof TPROXY support when forwarding
3488 requests to this peer. Use normal address selection instead.
3489 This overrides the spoof_client_ip ACL.
3491 proxy-only objects fetched from the peer will not be stored locally.
3495 NAME: cache_peer_access
3500 Use to limit the requests for which a neighbor proxy will be
3501 queried. Peers with no restrictions are queried for all requests.
3504 cache_peer_access cache-host allow|deny [!]aclname ...
3506 The syntax is identical to 'http_access' and the other lists of
3507 ACL elements. See the comments for 'http_access', or the
3508 Squid FAQ (http://wiki.squid-cache.org/SquidFaq/SquidAcl).
3511 NAME: neighbor_type_domain
3512 TYPE: hostdomaintype
3514 DEFAULT_DOC: The peer type from cache_peer directive is used for all requests to that peer.
3517 Modify the cache_peer neighbor type when passing requests
3518 about specific domains to the peer.
3521 neighbor_type_domain neighbor parent|sibling domain domain ...
3524 cache_peer foo.example.com parent 3128 3130
3525 neighbor_type_domain foo.example.com sibling .au .de
3527 The above configuration treats all requests to foo.example.com as a
3528 parent proxy unless the request is for a .au or .de ccTLD domain name.
3531 NAME: dead_peer_timeout
3535 LOC: Config.Timeout.deadPeer
3537 This controls how long Squid waits to declare a peer cache
3538 as "dead." If there are no ICP replies received in this
3539 amount of time, Squid will declare the peer dead and not
3540 expect to receive any further ICP replies. However, it
3541 continues to send ICP queries, and will mark the peer as
3542 alive upon receipt of the first subsequent ICP reply.
3544 This timeout also affects when Squid expects to receive ICP
3545 replies from peers. If more than 'dead_peer' seconds have
3546 passed since the last ICP reply was received, Squid will not
3547 expect to receive an ICP reply on the next query. Thus, if
3548 your time between requests is greater than this timeout, you
3549 will see a lot of requests sent DIRECT to origin servers
3550 instead of to your parents.
3553 NAME: forward_max_tries
3556 LOC: Config.forward_max_tries
3558 Controls how many different forward paths Squid will try
3559 before giving up. See also forward_timeout.
3561 NOTE: connect_retries (default: none) can make each of these
3562 possible forwarding paths be tried multiple times.
3566 MEMORY CACHE OPTIONS
3567 -----------------------------------------------------------------------------
3574 LOC: Config.memMaxSize
3576 NOTE: THIS PARAMETER DOES NOT SPECIFY THE MAXIMUM PROCESS SIZE.
3577 IT ONLY PLACES A LIMIT ON HOW MUCH ADDITIONAL MEMORY SQUID WILL
3578 USE AS A MEMORY CACHE OF OBJECTS. SQUID USES MEMORY FOR OTHER
3579 THINGS AS WELL. SEE THE SQUID FAQ SECTION 8 FOR DETAILS.
3581 'cache_mem' specifies the ideal amount of memory to be used
3583 * In-Transit objects
3585 * Negative-Cached objects
3587 Data for these objects are stored in 4 KB blocks. This
3588 parameter specifies the ideal upper limit on the total size of
3589 4 KB blocks allocated. In-Transit objects take the highest
3592 In-transit objects have priority over the others. When
3593 additional space is needed for incoming data, negative-cached
3594 and hot objects will be released. In other words, the
3595 negative-cached and hot objects will fill up any unused space
3596 not needed for in-transit objects.
3598 If circumstances require, this limit will be exceeded.
3599 Specifically, if your incoming request rate requires more than
3600 'cache_mem' of memory to hold in-transit objects, Squid will
3601 exceed this limit to satisfy the new requests. When the load
3602 decreases, blocks will be freed until the high-water mark is
3603 reached. Thereafter, blocks will be used to store hot
3606 If shared memory caching is enabled, Squid does not use the shared
3607 cache space for in-transit objects, but they still consume as much
3608 local memory as they need. For more details about the shared memory
3609 cache, see memory_cache_shared.
3612 NAME: maximum_object_size_in_memory
3616 LOC: Config.Store.maxInMemObjSize
3618 Objects greater than this size will not be attempted to kept in
3619 the memory cache. This should be set high enough to keep objects
3620 accessed frequently in memory to improve performance whilst low
3621 enough to keep larger objects from hoarding cache_mem.
3624 NAME: memory_cache_shared
3627 LOC: Config.memShared
3629 DEFAULT_DOC: "on" where supported if doing memory caching with multiple SMP workers.
3631 Controls whether the memory cache is shared among SMP workers.
3633 The shared memory cache is meant to occupy cache_mem bytes and replace
3634 the non-shared memory cache, although some entities may still be
3635 cached locally by workers for now (e.g., internal and in-transit
3636 objects may be served from a local memory cache even if shared memory
3637 caching is enabled).
3639 By default, the memory cache is shared if and only if all of the
3640 following conditions are satisfied: Squid runs in SMP mode with
3641 multiple workers, cache_mem is positive, and Squid environment
3642 supports required IPC primitives (e.g., POSIX shared memory segments
3643 and GCC-style atomic operations).
3645 To avoid blocking locks, shared memory uses opportunistic algorithms
3646 that do not guarantee that every cachable entity that could have been
3647 shared among SMP workers will actually be shared.
3649 Currently, entities exceeding 32KB in size cannot be shared.
3652 NAME: memory_cache_mode
3656 DEFAULT_DOC: Keep the most recently fetched objects in memory
3658 Controls which objects to keep in the memory cache (cache_mem)
3660 always Keep most recently fetched objects in memory (default)
3662 disk Only disk cache hits are kept in memory, which means
3663 an object must first be cached on disk and then hit
3664 a second time before cached in memory.
3666 network Only objects fetched from network is kept in memory
3669 NAME: memory_replacement_policy
3671 LOC: Config.memPolicy
3674 The memory replacement policy parameter determines which
3675 objects are purged from memory when memory space is needed.
3677 See cache_replacement_policy for details on algorithms.
3682 -----------------------------------------------------------------------------
3685 NAME: cache_replacement_policy
3687 LOC: Config.replPolicy
3690 The cache replacement policy parameter determines which
3691 objects are evicted (replaced) when disk space is needed.
3693 lru : Squid's original list based LRU policy
3694 heap GDSF : Greedy-Dual Size Frequency
3695 heap LFUDA: Least Frequently Used with Dynamic Aging
3696 heap LRU : LRU policy implemented using a heap
3698 Applies to any cache_dir lines listed below this directive.
3700 The LRU policies keeps recently referenced objects.
3702 The heap GDSF policy optimizes object hit rate by keeping smaller
3703 popular objects in cache so it has a better chance of getting a
3704 hit. It achieves a lower byte hit rate than LFUDA though since
3705 it evicts larger (possibly popular) objects.
3707 The heap LFUDA policy keeps popular objects in cache regardless of
3708 their size and thus optimizes byte hit rate at the expense of
3709 hit rate since one large, popular object will prevent many
3710 smaller, slightly less popular objects from being cached.
3712 Both policies utilize a dynamic aging mechanism that prevents
3713 cache pollution that can otherwise occur with frequency-based
3714 replacement policies.
3716 NOTE: if using the LFUDA replacement policy you should increase
3717 the value of maximum_object_size above its default of 4 MB to
3718 to maximize the potential byte hit rate improvement of LFUDA.
3720 For more information about the GDSF and LFUDA cache replacement
3721 policies see http://www.hpl.hp.com/techreports/1999/HPL-1999-69.html
3722 and http://fog.hpl.external.hp.com/techreports/98/HPL-98-173.html.
3725 NAME: minimum_object_size
3729 DEFAULT_DOC: no limit
3730 LOC: Config.Store.minObjectSize
3732 Objects smaller than this size will NOT be saved on disk. The
3733 value is specified in bytes, and the default is 0 KB, which
3734 means all responses can be stored.
3737 NAME: maximum_object_size
3741 LOC: Config.Store.maxObjectSize
3743 Set the default value for max-size parameter on any cache_dir.
3744 The value is specified in bytes, and the default is 4 MB.
3746 If you wish to get a high BYTES hit ratio, you should probably
3747 increase this (one 32 MB object hit counts for 3200 10KB
3750 If you wish to increase hit ratio more than you want to
3751 save bandwidth you should leave this low.
3753 NOTE: if using the LFUDA replacement policy you should increase
3754 this value to maximize the byte hit rate improvement of LFUDA!
3755 See cache_replacement_policy for a discussion of this policy.
3761 DEFAULT_DOC: No disk cache. Store cache ojects only in memory.
3762 LOC: Config.cacheSwap
3765 cache_dir Type Directory-Name Fs-specific-data [options]
3767 You can specify multiple cache_dir lines to spread the
3768 cache among different disk partitions.
3770 Type specifies the kind of storage system to use. Only "ufs"
3771 is built by default. To enable any of the other storage systems
3772 see the --enable-storeio configure option.
3774 'Directory' is a top-level directory where cache swap
3775 files will be stored. If you want to use an entire disk
3776 for caching, this can be the mount-point directory.
3777 The directory must exist and be writable by the Squid
3778 process. Squid will NOT create this directory for you.
3780 In SMP configurations, cache_dir must not precede the workers option
3781 and should use configuration macros or conditionals to give each
3782 worker interested in disk caching a dedicated cache directory.
3785 ==== The ufs store type ====
3787 "ufs" is the old well-known Squid storage format that has always
3791 cache_dir ufs Directory-Name Mbytes L1 L2 [options]
3793 'Mbytes' is the amount of disk space (MB) to use under this
3794 directory. The default is 100 MB. Change this to suit your
3795 configuration. Do NOT put the size of your disk drive here.
3796 Instead, if you want Squid to use the entire disk drive,
3797 subtract 20% and use that value.
3799 'L1' is the number of first-level subdirectories which
3800 will be created under the 'Directory'. The default is 16.
3802 'L2' is the number of second-level subdirectories which
3803 will be created under each first-level directory. The default
3807 ==== The aufs store type ====
3809 "aufs" uses the same storage format as "ufs", utilizing
3810 POSIX-threads to avoid blocking the main Squid process on
3811 disk-I/O. This was formerly known in Squid as async-io.
3814 cache_dir aufs Directory-Name Mbytes L1 L2 [options]
3816 see argument descriptions under ufs above
3819 ==== The diskd store type ====
3821 "diskd" uses the same storage format as "ufs", utilizing a
3822 separate process to avoid blocking the main Squid process on
3826 cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n]
3828 see argument descriptions under ufs above
3830 Q1 specifies the number of unacknowledged I/O requests when Squid
3831 stops opening new files. If this many messages are in the queues,
3832 Squid won't open new files. Default is 64
3834 Q2 specifies the number of unacknowledged messages when Squid
3835 starts blocking. If this many messages are in the queues,
3836 Squid blocks until it receives some replies. Default is 72
3838 When Q1 < Q2 (the default), the cache directory is optimized
3839 for lower response time at the expense of a decrease in hit
3840 ratio. If Q1 > Q2, the cache directory is optimized for
3841 higher hit ratio at the expense of an increase in response
3845 ==== The rock store type ====
3848 cache_dir rock Directory-Name Mbytes [options]
3850 The Rock Store type is a database-style storage. All cached
3851 entries are stored in a "database" file, using fixed-size slots.
3852 A single entry occupies one or more slots.
3854 If possible, Squid using Rock Store creates a dedicated kid
3855 process called "disker" to avoid blocking Squid worker(s) on disk
3856 I/O. One disker kid is created for each rock cache_dir. Diskers
3857 are created only when Squid, running in daemon mode, has support
3858 for the IpcIo disk I/O module.
3860 swap-timeout=msec: Squid will not start writing a miss to or
3861 reading a hit from disk if it estimates that the swap operation
3862 will take more than the specified number of milliseconds. By
3863 default and when set to zero, disables the disk I/O time limit
3864 enforcement. Ignored when using blocking I/O module because
3865 blocking synchronous I/O does not allow Squid to estimate the
3866 expected swap wait time.
3868 max-swap-rate=swaps/sec: Artificially limits disk access using
3869 the specified I/O rate limit. Swap out requests that
3870 would cause the average I/O rate to exceed the limit are
3871 delayed. Individual swap in requests (i.e., hits or reads) are
3872 not delayed, but they do contribute to measured swap rate and
3873 since they are placed in the same FIFO queue as swap out
3874 requests, they may wait longer if max-swap-rate is smaller.
3875 This is necessary on file systems that buffer "too
3876 many" writes and then start blocking Squid and other processes
3877 while committing those writes to disk. Usually used together
3878 with swap-timeout to avoid excessive delays and queue overflows
3879 when disk demand exceeds available disk "bandwidth". By default
3880 and when set to zero, disables the disk I/O rate limit
3881 enforcement. Currently supported by IpcIo module only.
3883 slot-size=bytes: The size of a database "record" used for
3884 storing cached responses. A cached response occupies at least
3885 one slot and all database I/O is done using individual slots so
3886 increasing this parameter leads to more disk space waste while
3887 decreasing it leads to more disk I/O overheads. Should be a
3888 multiple of your operating system I/O page size. Defaults to
3889 16KBytes. A housekeeping header is stored with each slot and
3890 smaller slot-sizes will be rejected. The header is smaller than
3894 ==== COMMON OPTIONS ====
3896 no-store no new objects should be stored to this cache_dir.
3898 min-size=n the minimum object size in bytes this cache_dir
3899 will accept. It's used to restrict a cache_dir
3900 to only store large objects (e.g. AUFS) while
3901 other stores are optimized for smaller objects
3905 max-size=n the maximum object size in bytes this cache_dir
3907 The value in maximum_object_size directive sets
3908 the default unless more specific details are
3909 available (ie a small store capacity).
3911 Note: To make optimal use of the max-size limits you should order
3912 the cache_dir lines with the smallest max-size value first.
3916 # Uncomment and adjust the following to add a disk cache directory.
3917 #cache_dir ufs @DEFAULT_SWAP_DIR@ 100 16 256
3921 NAME: store_dir_select_algorithm
3923 LOC: Config.store_dir_select_algorithm
3926 How Squid selects which cache_dir to use when the response
3927 object will fit into more than one.
3929 Regardless of which algorithm is used the cache_dir min-size
3930 and max-size parameters are obeyed. As such they can affect
3931 the selection algorithm by limiting the set of considered
3938 This algorithm is suited to caches with similar cache_dir
3939 sizes and disk speeds.
3941 The disk with the least I/O pending is selected.
3942 When there are multiple disks with the same I/O load ranking
3943 the cache_dir with most available capacity is selected.
3945 When a mix of cache_dir sizes are configured the faster disks
3946 have a naturally lower I/O loading and larger disks have more
3947 capacity. So space used to store objects and data throughput
3948 may be very unbalanced towards larger disks.
3953 This algorithm is suited to caches with unequal cache_dir
3956 Each cache_dir is selected in a rotation. The next suitable
3959 Available cache_dir capacity is only considered in relation
3960 to whether the object will fit and meets the min-size and
3961 max-size parameters.
3963 Disk I/O loading is only considered to prevent overload on slow
3964 disks. This algorithm does not spread objects by size, so any
3965 I/O loading per-disk may appear very unbalanced and volatile.
3967 If several cache_dirs use similar min-size, max-size, or other
3968 limits to to reject certain responses, then do not group such
3969 cache_dir lines together, to avoid round-robin selection bias
3970 towards the first cache_dir after the group. Instead, interleave
3971 cache_dir lines from different groups. For example:
3973 store_dir_select_algorithm round-robin
3974 cache_dir rock /hdd1 ... min-size=100000
3975 cache_dir rock /ssd1 ... max-size=99999
3976 cache_dir rock /hdd2 ... min-size=100000
3977 cache_dir rock /ssd2 ... max-size=99999
3978 cache_dir rock /hdd3 ... min-size=100000
3979 cache_dir rock /ssd3 ... max-size=99999
3982 NAME: max_open_disk_fds
3984 LOC: Config.max_open_disk_fds
3986 DEFAULT_DOC: no limit
3988 To avoid having disk as the I/O bottleneck Squid can optionally
3989 bypass the on-disk cache if more than this amount of disk file
3990 descriptors are open.
3992 A value of 0 indicates no limit.
3995 NAME: cache_swap_low
3996 COMMENT: (percent, 0-100)
3999 LOC: Config.Swap.lowWaterMark
4001 The low-water mark for cache object replacement.
4002 Replacement begins when the swap (disk) usage is above the
4003 low-water mark and attempts to maintain utilization near the
4004 low-water mark. As swap utilization gets close to high-water
4005 mark object eviction becomes more aggressive. If utilization is
4006 close to the low-water mark less replacement is done each time.
4008 Defaults are 90% and 95%. If you have a large cache, 5% could be
4009 hundreds of MB. If this is the case you may wish to set these
4010 numbers closer together.
4012 See also cache_swap_high
4015 NAME: cache_swap_high
4016 COMMENT: (percent, 0-100)
4019 LOC: Config.Swap.highWaterMark
4021 The high-water mark for cache object replacement.
4022 Replacement begins when the swap (disk) usage is above the
4023 low-water mark and attempts to maintain utilization near the
4024 low-water mark. As swap utilization gets close to high-water
4025 mark object eviction becomes more aggressive. If utilization is
4026 close to the low-water mark less replacement is done each time.
4028 Defaults are 90% and 95%. If you have a large cache, 5% could be
4029 hundreds of MB. If this is the case you may wish to set these
4030 numbers closer together.
4032 See also cache_swap_low
4037 -----------------------------------------------------------------------------
4044 DEFAULT_DOC: The format definitions squid, common, combined, referrer, useragent are built in.
4048 logformat <name> <format specification>
4050 Defines an access log format.
4052 The <format specification> is a string with embedded % format codes
4054 % format codes all follow the same basic structure where all but
4055 the formatcode is optional. Output strings are automatically escaped
4056 as required according to their context and the output format
4057 modifiers are usually not needed, but can be specified if an explicit
4058 output format is desired.
4060 % ["|[|'|#] [-] [[0]width] [{argument}] formatcode
4062 " output in quoted string format
4063 [ output in squid text log format as used by log_mime_hdrs
4064 # output in URL quoted format
4069 width minimum and/or maximum field width:
4070 [width_min][.width_max]
4071 When minimum starts with 0, the field is zero-padded.
4072 String values exceeding maximum width are truncated.
4074 {arg} argument such as header name etc
4078 % a literal % character
4079 sn Unique sequence number per log line entry
4080 err_code The ID of an error response served by Squid or
4081 a similar internal error identifier.
4082 err_detail Additional err_code-dependent error information.
4083 note The annotation specified by the argument. Also
4084 logs the adaptation meta headers set by the
4085 adaptation_meta configuration parameter.
4086 If no argument given all annotations logged.
4087 The argument may include a separator to use with
4090 By default, multiple note values are separated with ","
4091 and multiple notes are separated with "\r\n".
4092 When logging named notes with %{name}note, the
4093 explicitly configured separator is used between note
4094 values. When logging all notes with %note, the
4095 explicitly configured separator is used between
4096 individual notes. There is currently no way to
4097 specify both value and notes separators when logging
4098 all notes with %note.
4100 Connection related format codes:
4102 >a Client source IP address
4104 >p Client source port
4105 >eui Client source EUI (MAC address, EUI-48 or EUI-64 identifier)
4106 >la Local IP address the client connected to
4107 >lp Local port number the client connected to
4108 >qos Client connection TOS/DSCP value set by Squid
4109 >nfmark Client connection netfilter mark set by Squid
4111 la Local listening IP address the client connection was connected to.
4112 lp Local listening port number the client connection was connected to.
4114 <a Server IP address of the last server or peer connection
4115 <A Server FQDN or peer name
4116 <p Server port number of the last server or peer connection
4117 <la Local IP address of the last server or peer connection
4118 <lp Local port number of the last server or peer connection
4119 <qos Server connection TOS/DSCP value set by Squid
4120 <nfmark Server connection netfilter mark set by Squid
4122 Time related format codes:
4124 ts Seconds since epoch
4125 tu subsecond time (milliseconds)
4126 tl Local time. Optional strftime format argument
4127 default %d/%b/%Y:%H:%M:%S %z
4128 tg GMT time. Optional strftime format argument
4129 default %d/%b/%Y:%H:%M:%S %z
4130 tr Response time (milliseconds)
4131 dt Total time spent making DNS lookups (milliseconds)
4132 tS Approximate master transaction start time in
4133 <full seconds since epoch>.<fractional seconds> format.
4134 Currently, Squid considers the master transaction
4135 started when a complete HTTP request header initiating
4136 the transaction is received from the client. This is
4137 the same value that Squid uses to calculate transaction
4138 response time when logging %tr to access.log. Currently,
4139 Squid uses millisecond resolution for %tS values,
4140 similar to the default access.log "current time" field
4143 Access Control related format codes:
4145 et Tag returned by external acl
4146 ea Log string returned by external acl
4147 un User name (any available)
4148 ul User name from authentication
4149 ue User name from external acl helper
4150 ui User name from ident
4151 us User name from SSL
4152 credentials Client credentials. The exact meaning depends on
4153 the authentication scheme: For Basic authentication,
4154 it is the password; for Digest, the realm sent by the
4155 client; for NTLM and Negotiate, the client challenge
4156 or client credentials prefixed with "YR " or "KK ".
4158 HTTP related format codes:
4162 [http::]rm Request method (GET/POST etc)
4163 [http::]>rm Request method from client
4164 [http::]<rm Request method sent to server or peer
4165 [http::]ru Request URL from client (historic, filtered for logging)
4166 [http::]>ru Request URL from client
4167 [http::]<ru Request URL sent to server or peer
4168 [http::]>rs Request URL scheme from client
4169 [http::]<rs Request URL scheme sent to server or peer
4170 [http::]>rd Request URL domain from client
4171 [http::]<rd Request URL domain sent to server or peer
4172 [http::]>rP Request URL port from client
4173 [http::]<rP Request URL port sent to server or peer
4174 [http::]rp Request URL path excluding hostname
4175 [http::]>rp Request URL path excluding hostname from client
4176 [http::]<rp Request URL path excluding hostname sent to server or peer
4177 [http::]rv Request protocol version
4178 [http::]>rv Request protocol version from client
4179 [http::]<rv Request protocol version sent to server or peer
4181 [http::]>h Original received request header.
4182 Usually differs from the request header sent by
4183 Squid, although most fields are often preserved.
4184 Accepts optional header field name/value filter
4185 argument using name[:[separator]element] format.
4186 [http::]>ha Received request header after adaptation and
4187 redirection (pre-cache REQMOD vectoring point).
4188 Usually differs from the request header sent by
4189 Squid, although most fields are often preserved.
4190 Optional header name argument as for >h
4195 [http::]<Hs HTTP status code received from the next hop
4196 [http::]>Hs HTTP status code sent to the client
4198 [http::]<h Reply header. Optional header name argument
4201 [http::]mt MIME content type
4206 [http::]st Total size of request + reply traffic with client
4207 [http::]>st Total size of request received from client.
4208 Excluding chunked encoding bytes.
4209 [http::]<st Total size of reply sent to client (after adaptation)
4211 [http::]>sh Size of request headers received from client
4212 [http::]<sh Size of reply headers sent to client (after adaptation)
4214 [http::]<sH Reply high offset sent
4215 [http::]<sS Upstream object size
4217 [http::]<bs Number of HTTP-equivalent message body bytes
4218 received from the next hop, excluding chunked
4219 transfer encoding and control messages.
4220 Generated FTP/Gopher listings are treated as
4226 [http::]<pt Peer response time in milliseconds. The timer starts
4227 when the last request byte is sent to the next hop
4228 and stops when the last response byte is received.
4229 [http::]<tt Total time in milliseconds. The timer
4230 starts with the first connect request (or write I/O)
4231 sent to the first selected peer. The timer stops
4232 with the last I/O with the last peer.
4234 Squid handling related format codes:
4236 Ss Squid request status (TCP_MISS etc)
4237 Sh Squid hierarchy status (DEFAULT_PARENT etc)
4239 SSL-related format codes:
4241 ssl::bump_mode SslBump decision for the transaction:
4243 For CONNECT requests that initiated bumping of
4244 a connection and for any request received on
4245 an already bumped connection, Squid logs the
4246 corresponding SslBump mode ("server-first" or
4247 "client-first"). See the ssl_bump option for
4248 more information about these modes.
4250 A "none" token is logged for requests that
4251 triggered "ssl_bump" ACL evaluation matching
4252 either a "none" rule or no rules at all.
4254 In all other cases, a single dash ("-") is
4257 ssl::>sni SSL client SNI sent to Squid. Available only
4258 after the peek, stare, or splice SSL bumping
4261 If ICAP is enabled, the following code becomes available (as
4262 well as ICAP log codes documented with the icap_log option):
4264 icap::tt Total ICAP processing time for the HTTP
4265 transaction. The timer ticks when ICAP
4266 ACLs are checked and when ICAP
4267 transaction is in progress.
4269 If adaptation is enabled the following three codes become available:
4271 adapt::<last_h The header of the last ICAP response or
4272 meta-information from the last eCAP
4273 transaction related to the HTTP transaction.
4274 Like <h, accepts an optional header name
4277 adapt::sum_trs Summed adaptation transaction response
4278 times recorded as a comma-separated list in
4279 the order of transaction start time. Each time
4280 value is recorded as an integer number,
4281 representing response time of one or more
4282 adaptation (ICAP or eCAP) transaction in
4283 milliseconds. When a failed transaction is
4284 being retried or repeated, its time is not
4285 logged individually but added to the
4286 replacement (next) transaction. See also:
4289 adapt::all_trs All adaptation transaction response times.
4290 Same as adaptation_strs but response times of
4291 individual transactions are never added
4292 together. Instead, all transaction response
4293 times are recorded individually.
4295 You can prefix adapt::*_trs format codes with adaptation
4296 service name in curly braces to record response time(s) specific
4297 to that service. For example: %{my_service}adapt::sum_trs
4299 If SSL is enabled, the following formating codes become available:
4301 %ssl::>cert_subject The Subject field of the received client
4302 SSL certificate or a dash ('-') if Squid has
4303 received an invalid/malformed certificate or
4304 no certificate at all. Consider encoding the
4305 logged value because Subject often has spaces.
4307 %ssl::>cert_issuer The Issuer field of the received client
4308 SSL certificate or a dash ('-') if Squid has
4309 received an invalid/malformed certificate or
4310 no certificate at all. Consider encoding the
4311 logged value because Issuer often has spaces.
4313 The default formats available (which do not need re-defining) are:
4315 logformat squid %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %[un %Sh/%<a %mt
4316 logformat common %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st %Ss:%Sh
4317 logformat combined %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
4318 logformat referrer %ts.%03tu %>a %{Referer}>h %ru
4319 logformat useragent %>a [%tl] "%{User-Agent}>h"
4321 NOTE: When the log_mime_hdrs directive is set to ON.
4322 The squid, common and combined formats have a safely encoded copy
4323 of the mime headers appended to each line within a pair of brackets.
4325 NOTE: The common and combined formats are not quite true to the Apache definition.
4326 The logs from Squid contain an extra status and hierarchy code appended.
4330 NAME: access_log cache_access_log
4332 LOC: Config.Log.accesslogs
4333 DEFAULT_IF_NONE: daemon:@DEFAULT_ACCESS_LOG@ squid
4335 Configures whether and how Squid logs HTTP and ICP transactions.
4336 If access logging is enabled, a single line is logged for every
4337 matching HTTP or ICP request. The recommended directive formats are:
4339 access_log <module>:<place> [option ...] [acl acl ...]
4340 access_log none [acl acl ...]
4342 The following directive format is accepted but may be deprecated:
4343 access_log <module>:<place> [<logformat name> [acl acl ...]]
4345 In most cases, the first ACL name must not contain the '=' character
4346 and should not be equal to an existing logformat name. You can always
4347 start with an 'all' ACL to work around those restrictions.
4349 Will log to the specified module:place using the specified format (which
4350 must be defined in a logformat directive) those entries which match
4351 ALL the acl's specified (which must be defined in acl clauses).
4352 If no acl is specified, all requests will be logged to this destination.
4354 ===== Available options for the recommended directive format =====
4356 logformat=name Names log line format (either built-in or
4357 defined by a logformat directive). Defaults
4360 buffer-size=64KB Defines approximate buffering limit for log
4361 records (see buffered_logs). Squid should not
4362 keep more than the specified size and, hence,
4363 should flush records before the buffer becomes
4364 full to avoid overflows under normal
4365 conditions (the exact flushing algorithm is
4366 module-dependent though). The on-error option
4367 controls overflow handling.
4369 on-error=die|drop Defines action on unrecoverable errors. The
4370 'drop' action ignores (i.e., does not log)
4371 affected log records. The default 'die' action
4372 kills the affected worker. The drop action
4373 support has not been tested for modules other
4376 rotate=N Specifies the number of log file rotations to
4377 make when you run 'squid -k rotate'. The default
4378 is to obey the logfile_rotate directive. Setting
4379 rotate=0 will disable the file name rotation,
4380 but the log files are still closed and re-opened.
4381 This will enable you to rename the logfiles
4382 yourself just before sending the rotate signal.
4383 Only supported by the stdio module.
4385 ===== Modules Currently available =====
4387 none Do not log any requests matching these ACL.
4388 Do not specify Place or logformat name.
4390 stdio Write each log line to disk immediately at the completion of
4392 Place: the filename and path to be written.
4394 daemon Very similar to stdio. But instead of writing to disk the log
4395 line is passed to a daemon helper for asychronous handling instead.
4396 Place: varies depending on the daemon.
4398 log_file_daemon Place: the file name and path to be written.
4400 syslog To log each request via syslog facility.
4401 Place: The syslog facility and priority level for these entries.
4402 Place Format: facility.priority
4404 where facility could be any of:
4405 authpriv, daemon, local0 ... local7 or user.
4407 And priority could be any of:
4408 err, warning, notice, info, debug.
4410 udp To send each log line as text data to a UDP receiver.
4411 Place: The destination host name or IP and port.
4412 Place Format: //host:port
4414 tcp To send each log line as text data to a TCP receiver.
4415 Lines may be accumulated before sending (see buffered_logs).
4416 Place: The destination host name or IP and port.
4417 Place Format: //host:port
4420 access_log daemon:@DEFAULT_ACCESS_LOG@ squid
4426 LOC: Config.Log.icaplogs
4429 ICAP log files record ICAP transaction summaries, one line per
4432 The icap_log option format is:
4433 icap_log <filepath> [<logformat name> [acl acl ...]]
4434 icap_log none [acl acl ...]]
4436 Please see access_log option documentation for details. The two
4437 kinds of logs share the overall configuration approach and many
4440 ICAP processing of a single HTTP message or transaction may
4441 require multiple ICAP transactions. In such cases, multiple
4442 ICAP transaction log lines will correspond to a single access
4445 ICAP log uses logformat codes that make sense for an ICAP
4446 transaction. Header-related codes are applied to the HTTP header
4447 embedded in an ICAP server response, with the following caveats:
4448 For REQMOD, there is no HTTP response header unless the ICAP
4449 server performed request satisfaction. For RESPMOD, the HTTP
4450 request header is the header sent to the ICAP server. For
4451 OPTIONS, there are no HTTP headers.
4453 The following format codes are also available for ICAP logs:
4455 icap::<A ICAP server IP address. Similar to <A.
4457 icap::<service_name ICAP service name from the icap_service
4458 option in Squid configuration file.
4460 icap::ru ICAP Request-URI. Similar to ru.
4462 icap::rm ICAP request method (REQMOD, RESPMOD, or
4463 OPTIONS). Similar to existing rm.
4465 icap::>st Bytes sent to the ICAP server (TCP payload
4466 only; i.e., what Squid writes to the socket).
4468 icap::<st Bytes received from the ICAP server (TCP
4469 payload only; i.e., what Squid reads from
4472 icap::<bs Number of message body bytes received from the
4473 ICAP server. ICAP message body, if any, usually
4474 includes encapsulated HTTP message headers and
4475 possibly encapsulated HTTP message body. The
4476 HTTP body part is dechunked before its size is
4479 icap::tr Transaction response time (in
4480 milliseconds). The timer starts when
4481 the ICAP transaction is created and
4482 stops when the transaction is completed.
4485 icap::tio Transaction I/O time (in milliseconds). The
4486 timer starts when the first ICAP request
4487 byte is scheduled for sending. The timers
4488 stops when the last byte of the ICAP response
4491 icap::to Transaction outcome: ICAP_ERR* for all
4492 transaction errors, ICAP_OPT for OPTION
4493 transactions, ICAP_ECHO for 204
4494 responses, ICAP_MOD for message
4495 modification, and ICAP_SAT for request
4496 satisfaction. Similar to Ss.
4498 icap::Hs ICAP response status code. Similar to Hs.
4500 icap::>h ICAP request header(s). Similar to >h.
4502 icap::<h ICAP response header(s). Similar to <h.
4504 The default ICAP log format, which can be used without an explicit
4505 definition, is called icap_squid:
4507 logformat icap_squid %ts.%03tu %6icap::tr %>a %icap::to/%03icap::Hs %icap::<size %icap::rm %icap::ru% %un -/%icap::<A -
4509 See also: logformat, log_icap, and %adapt::<last_h
4512 NAME: logfile_daemon
4514 DEFAULT: @DEFAULT_LOGFILED@
4515 LOC: Log::TheConfig.logfile_daemon
4517 Specify the path to the logfile-writing daemon. This daemon is
4518 used to write the access and store logs, if configured.
4520 Squid sends a number of commands to the log daemon:
4521 L<data>\n - logfile data
4526 r<n>\n - set rotate count to <n>
4527 b<n>\n - 1 = buffer output, 0 = don't buffer output
4529 No responses is expected.
4532 NAME: stats_collection
4534 LOC: Config.accessList.stats_collection
4536 DEFAULT_DOC: Allow logging for all transactions.
4537 COMMENT: allow|deny acl acl...
4539 This options allows you to control which requests gets accounted
4540 in performance counters.
4542 This clause only supports fast acl types.
4543 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4546 NAME: cache_store_log
4549 LOC: Config.Log.store
4551 Logs the activities of the storage manager. Shows which
4552 objects are ejected from the cache, and which objects are
4553 saved and for how long.
4554 There are not really utilities to analyze this data, so you can safely
4555 disable it (the default).
4557 Store log uses modular logging outputs. See access_log for the list
4558 of modules supported.
4561 cache_store_log stdio:@DEFAULT_STORE_LOG@
4562 cache_store_log daemon:@DEFAULT_STORE_LOG@
4565 NAME: cache_swap_state cache_swap_log
4567 LOC: Config.Log.swap
4569 DEFAULT_DOC: Store the journal inside its cache_dir
4571 Location for the cache "swap.state" file. This index file holds
4572 the metadata of objects saved on disk. It is used to rebuild
4573 the cache during startup. Normally this file resides in each
4574 'cache_dir' directory, but you may specify an alternate
4575 pathname here. Note you must give a full filename, not just
4576 a directory. Since this is the index for the whole object
4577 list you CANNOT periodically rotate it!
4579 If %s can be used in the file name it will be replaced with a
4580 a representation of the cache_dir name where each / is replaced
4581 with '.'. This is needed to allow adding/removing cache_dir
4582 lines when cache_swap_log is being used.
4584 If have more than one 'cache_dir', and %s is not used in the name
4585 these swap logs will have names such as:
4591 The numbered extension (which is added automatically)
4592 corresponds to the order of the 'cache_dir' lines in this
4593 configuration file. If you change the order of the 'cache_dir'
4594 lines in this file, these index files will NOT correspond to
4595 the correct 'cache_dir' entry (unless you manually rename
4596 them). We recommend you do NOT use this option. It is
4597 better to keep these index files in each 'cache_dir' directory.
4600 NAME: logfile_rotate
4603 LOC: Config.Log.rotateNumber
4605 Specifies the default number of logfile rotations to make when you
4606 type 'squid -k rotate'. The default is 10, which will rotate
4607 with extensions 0 through 9. Setting logfile_rotate to 0 will
4608 disable the file name rotation, but the logfiles are still closed
4609 and re-opened. This will enable you to rename the logfiles
4610 yourself just before sending the rotate signal.
4612 Note, from Squid-3.1 this option is only a default for cache.log,
4613 that log can be rotated separately by using debug_options.
4615 Note, from Squid-3.6 this option is only a default for access.log
4616 recorded by stdio: module. Those logs can be rotated separately by
4617 using the rotate=N option on their access_log directive.
4619 Note, the 'squid -k rotate' command normally sends a USR1
4620 signal to the running squid process. In certain situations
4621 (e.g. on Linux with Async I/O), USR1 is used for other
4622 purposes, so -k rotate uses another signal. It is best to get
4623 in the habit of using 'squid -k rotate' instead of 'kill -USR1
4630 DEFAULT: @DEFAULT_MIME_TABLE@
4631 LOC: Config.mimeTablePathname
4633 Path to Squid's icon configuration file.
4635 You shouldn't need to change this, but the default file contains
4636 examples and formatting information if you do.
4642 LOC: Config.onoff.log_mime_hdrs
4645 The Cache can record both the request and the response MIME
4646 headers for each HTTP transaction. The headers are encoded
4647 safely and will appear as two bracketed fields at the end of
4648 the access log (for either the native or httpd-emulated log
4649 formats). To enable this logging set log_mime_hdrs to 'on'.
4654 DEFAULT: @DEFAULT_PID_FILE@
4655 LOC: Config.pidFilename
4657 A filename to write the process-id to. To disable, enter "none".
4660 NAME: client_netmask
4662 LOC: Config.Addrs.client_netmask
4664 DEFAULT_DOC: Log full client IP address
4666 A netmask for client addresses in logfiles and cachemgr output.
4667 Change this to protect the privacy of your cache clients.
4668 A netmask of 255.255.255.0 will log all IP's in that range with
4669 the last digit set to '0'.
4672 NAME: strip_query_terms
4674 LOC: Config.onoff.strip_query_terms
4677 By default, Squid strips query terms from requested URLs before
4678 logging. This protects your user's privacy and reduces log size.
4680 When investigating HIT/MISS or other caching behaviour you
4681 will need to disable this to see the full URL used by Squid.
4688 LOC: Config.onoff.buffered_logs
4690 Whether to write/send access_log records ASAP or accumulate them and
4691 then write/send them in larger chunks. Buffering may improve
4692 performance because it decreases the number of I/Os. However,
4693 buffering increases the delay before log records become available to
4694 the final recipient (e.g., a disk file or logging daemon) and,
4695 hence, increases the risk of log records loss.
4697 Note that even when buffered_logs are off, Squid may have to buffer
4698 records if it cannot write/send them immediately due to pending I/Os
4699 (e.g., the I/O writing the previous log record) or connectivity loss.
4701 Currently honored by 'daemon' and 'tcp' access_log modules only.
4704 NAME: netdb_filename
4706 DEFAULT: stdio:@DEFAULT_NETDB_FILE@
4707 LOC: Config.netdbFilename
4710 Where Squid stores it's netdb journal.
4711 When enabled this journal preserves netdb state between restarts.
4713 To disable, enter "none".
4717 OPTIONS FOR TROUBLESHOOTING
4718 -----------------------------------------------------------------------------
4723 DEFAULT_IF_NONE: @DEFAULT_CACHE_LOG@
4724 LOC: Debug::cache_log
4726 Squid administrative logging file.
4728 This is where general information about Squid behavior goes. You can
4729 increase the amount of data logged to this file and how often it is
4730 rotated with "debug_options"
4736 DEFAULT_DOC: Log all critical and important messages.
4737 LOC: Debug::debugOptions
4739 Logging options are set as section,level where each source file
4740 is assigned a unique section. Lower levels result in less
4741 output, Full debugging (level 9) can result in a very large
4742 log file, so be careful.
4744 The magic word "ALL" sets debugging levels for all sections.
4745 The default is to run with "ALL,1" to record important warnings.
4747 The rotate=N option can be used to keep more or less of these logs
4748 than would otherwise be kept by logfile_rotate.
4749 For most uses a single log should be enough to monitor current
4750 events affecting Squid.
4755 LOC: Config.coredump_dir
4756 DEFAULT_IF_NONE: none
4757 DEFAULT_DOC: Use the directory from where Squid was started.
4759 By default Squid leaves core files in the directory from where
4760 it was started. If you set 'coredump_dir' to a directory
4761 that exists, Squid will chdir() to that directory at startup
4762 and coredump files will be left there.
4766 # Leave coredumps in the first cache dir
4767 coredump_dir @DEFAULT_SWAP_DIR@
4773 OPTIONS FOR FTP GATEWAYING
4774 -----------------------------------------------------------------------------
4780 LOC: Config.Ftp.anon_user
4782 If you want the anonymous login password to be more informative
4783 (and enable the use of picky FTP servers), set this to something
4784 reasonable for your domain, like wwwuser@somewhere.net
4786 The reason why this is domainless by default is the
4787 request can be made on the behalf of a user in any domain,
4788 depending on how the cache is used.
4789 Some FTP server also validate the email address is valid
4790 (for example perl.com).
4796 LOC: Config.Ftp.passive
4798 If your firewall does not allow Squid to use passive
4799 connections, turn off this option.
4801 Use of ftp_epsv_all option requires this to be ON.
4807 LOC: Config.Ftp.epsv_all
4809 FTP Protocol extensions permit the use of a special "EPSV ALL" command.
4811 NATs may be able to put the connection on a "fast path" through the
4812 translator, as the EPRT command will never be used and therefore,
4813 translation of the data portion of the segments will never be needed.
4815 When a client only expects to do two-way FTP transfers this may be
4817 If squid finds that it must do a three-way FTP transfer after issuing
4818 an EPSV ALL command, the FTP session will fail.
4820 If you have any doubts about this option do not use it.
4821 Squid will nicely attempt all other connection methods.
4823 Requires ftp_passive to be ON (default) for any effect.
4829 LOC: Config.accessList.ftp_epsv
4831 FTP Protocol extensions permit the use of a special "EPSV" command.
4833 NATs may be able to put the connection on a "fast path" through the
4834 translator using EPSV, as the EPRT command will never be used
4835 and therefore, translation of the data portion of the segments
4836 will never be needed.
4838 EPSV is often required to interoperate with FTP servers on IPv6
4839 networks. On the other hand, it may break some IPv4 servers.
4841 By default, EPSV may try EPSV with any FTP server. To fine tune
4842 that decision, you may restrict EPSV to certain clients or servers
4845 ftp_epsv allow|deny al1 acl2 ...
4847 WARNING: Disabling EPSV may cause problems with external NAT and IPv6.
4849 Only fast ACLs are supported.
4850 Requires ftp_passive to be ON (default) for any effect.
4856 LOC: Config.Ftp.eprt
4858 FTP Protocol extensions permit the use of a special "EPRT" command.
4860 This extension provides a protocol neutral alternative to the
4861 IPv4-only PORT command. When supported it enables active FTP data
4862 channels over IPv6 and efficient NAT handling.
4864 Turning this OFF will prevent EPRT being attempted and will skip
4865 straight to using PORT for IPv4 servers.
4867 Some devices are known to not handle this extension correctly and
4868 may result in crashes. Devices which suport EPRT enough to fail
4869 cleanly will result in Squid attempting PORT anyway. This directive
4870 should only be disabled when EPRT results in device failures.
4872 WARNING: Doing so will convert Squid back to the old behavior with all
4873 the related problems with external NAT devices/layers and IPv4-only FTP.
4876 NAME: ftp_sanitycheck
4879 LOC: Config.Ftp.sanitycheck
4881 For security and data integrity reasons Squid by default performs
4882 sanity checks of the addresses of FTP data connections ensure the
4883 data connection is to the requested server. If you need to allow
4884 FTP connections to servers using another IP address for the data
4885 connection turn this off.
4888 NAME: ftp_telnet_protocol
4891 LOC: Config.Ftp.telnet
4893 The FTP protocol is officially defined to use the telnet protocol
4894 as transport channel for the control connection. However, many
4895 implementations are broken and does not respect this aspect of
4898 If you have trouble accessing files with ASCII code 255 in the
4899 path or similar problems involving this ASCII code you can
4900 try setting this directive to off. If that helps, report to the
4901 operator of the FTP server in question that their FTP server
4902 is broken and does not follow the FTP standard.
4906 OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
4907 -----------------------------------------------------------------------------
4912 DEFAULT: @DEFAULT_DISKD@
4913 LOC: Config.Program.diskd
4915 Specify the location of the diskd executable.
4916 Note this is only useful if you have compiled in
4917 diskd as one of the store io modules.
4920 NAME: unlinkd_program
4923 DEFAULT: @DEFAULT_UNLINKD@
4924 LOC: Config.Program.unlinkd
4926 Specify the location of the executable for file deletion process.
4929 NAME: pinger_program
4932 DEFAULT: @DEFAULT_PINGER@
4935 Specify the location of the executable for the pinger process.
4944 Control whether the pinger is active at run-time.
4945 Enables turning ICMP pinger on and off with a simple
4946 squid -k reconfigure.
4951 OPTIONS FOR URL REWRITING
4952 -----------------------------------------------------------------------------
4955 NAME: url_rewrite_program redirect_program
4957 LOC: Config.Program.redirect
4960 Specify the location of the executable URL rewriter to use.
4961 Since they can perform almost any function there isn't one included.
4963 For each requested URL, the rewriter will receive on line with the format
4965 [channel-ID <SP>] URL [<SP> extras]<NL>
4967 See url_rewrite_extras on how to send "extras" with optional values to
4969 After processing the request the helper must reply using the following format:
4971 [channel-ID <SP>] result [<SP> kv-pairs]
4973 The result code can be:
4975 OK status=30N url="..."
4976 Redirect the URL to the one supplied in 'url='.
4977 'status=' is optional and contains the status code to send
4978 the client in Squids HTTP response. It must be one of the
4979 HTTP redirect status codes: 301, 302, 303, 307, 308.
4980 When no status is given Squid will use 302.
4982 OK rewrite-url="..."
4983 Rewrite the URL to the one supplied in 'rewrite-url='.
4984 The new URL is fetched directly by Squid and returned to
4985 the client as the response to its request.
4988 When neither of url= and rewrite-url= are sent Squid does
4992 Do not change the URL.
4995 An internal error occurred in the helper, preventing
4996 a result being identified. The 'message=' key name is
4997 reserved for delivering a log message.
5000 In addition to the above kv-pairs Squid also understands the following
5001 optional kv-pairs received from URL rewriters:
5003 Associates a TAG with the client TCP connection.
5004 The TAG is treated as a regular annotation but persists across
5005 future requests on the client connection rather than just the
5006 current request. A helper may update the TAG during subsequent
5007 requests be returning a new kv-pair.
5009 When using the concurrency= option the protocol is changed by
5010 introducing a query channel tag in front of the request/response.
5011 The query channel tag is a number between 0 and concurrency-1.
5012 This value must be echoed back unchanged to Squid as the first part
5013 of the response relating to its request.
5015 WARNING: URL re-writing ability should be avoided whenever possible.
5016 Use the URL redirect form of response instead.
5018 Re-write creates a difference in the state held by the client
5019 and server. Possibly causing confusion when the server response
5020 contains snippets of its view state. Embeded URLs, response
5021 and content Location headers, etc. are not re-written by this
5024 By default, a URL rewriter is not used.
5027 NAME: url_rewrite_children redirect_children
5028 TYPE: HelperChildConfig
5029 DEFAULT: 20 startup=0 idle=1 concurrency=0
5030 LOC: Config.redirectChildren
5032 The maximum number of redirector processes to spawn. If you limit
5033 it too few Squid will have to wait for them to process a backlog of
5034 URLs, slowing it down. If you allow too many they will use RAM
5035 and other system resources noticably.
5037 The startup= and idle= options allow some measure of skew in your
5042 Sets a minimum of how many processes are to be spawned when Squid
5043 starts or reconfigures. When set to zero the first request will
5044 cause spawning of the first child process to handle it.
5046 Starting too few will cause an initial slowdown in traffic as Squid
5047 attempts to simultaneously spawn enough processes to cope.
5051 Sets a minimum of how many processes Squid is to try and keep available
5052 at all times. When traffic begins to rise above what the existing
5053 processes can handle this many more will be spawned up to the maximum
5054 configured. A minimum setting of 1 is required.
5058 The number of requests each redirector helper can handle in
5059 parallel. Defaults to 0 which indicates the redirector
5060 is a old-style single threaded redirector.
5062 When this directive is set to a value >= 1 then the protocol
5063 used to communicate with the helper is modified to include
5064 an ID in front of the request/response. The ID from the request
5065 must be echoed back with the response to that request.
5069 Sets the maximum number of queued requests.
5070 If the queued requests exceed queue size and redirector_bypass
5071 configuration option is set, then redirector is bypassed. Otherwise, if
5072 overloading persists squid may abort its operation.
5073 The default value is set to 2*numberofchildren.
5076 NAME: url_rewrite_host_header redirect_rewrites_host_header
5079 LOC: Config.onoff.redir_rewrites_host
5081 To preserve same-origin security policies in browsers and
5082 prevent Host: header forgery by redirectors Squid rewrites
5083 any Host: header in redirected requests.
5085 If you are running an accelerator this may not be a wanted
5086 effect of a redirector. This directive enables you disable
5087 Host: alteration in reverse-proxy traffic.
5089 WARNING: Entries are cached on the result of the URL rewriting
5090 process, so be careful if you have domain-virtual hosts.
5092 WARNING: Squid and other software verifies the URL and Host
5093 are matching, so be careful not to relay through other proxies
5094 or inspecting firewalls with this disabled.
5097 NAME: url_rewrite_access redirector_access
5100 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
5101 LOC: Config.accessList.redirector
5103 If defined, this access list specifies which requests are
5104 sent to the redirector processes.
5106 This clause supports both fast and slow acl types.
5107 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5110 NAME: url_rewrite_bypass redirector_bypass
5112 LOC: Config.onoff.redirector_bypass
5115 When this is 'on', a request will not go through the
5116 redirector if all the helpers are busy. If this is 'off'
5117 and the redirector queue grows too large, Squid will exit
5118 with a FATAL error and ask you to increase the number of
5119 redirectors. You should only enable this if the redirectors
5120 are not critical to your caching system. If you use
5121 redirectors for access control, and you enable this option,
5122 users may have access to pages they should not
5123 be allowed to request.
5124 This options sets default queue-size option of the url_rewrite_children
5128 NAME: url_rewrite_extras
5129 TYPE: TokenOrQuotedString
5130 LOC: Config.redirector_extras
5131 DEFAULT: "%>a/%>A %un %>rm myip=%la myport=%lp"
5133 Specifies a string to be append to request line format for the
5134 rewriter helper. "Quoted" format values may contain spaces and
5135 logformat %macros. In theory, any logformat %macro can be used.
5136 In practice, a %macro expands as a dash (-) if the helper request is
5137 sent before the required macro information is available to Squid.
5140 NAME: url_rewrite_timeout
5141 TYPE: UrlHelperTimeout
5142 LOC: Config.onUrlRewriteTimeout
5144 DEFAULT_DOC: Squid waits for the helper response forever
5146 Squid times active requests to redirector. The timeout value and Squid
5147 reaction to a timed out request are configurable using the following
5150 url_rewrite_timeout timeout time-units on_timeout=<action> [response=<quoted-response>]
5152 supported timeout actions:
5153 fail Squid return a ERR_GATEWAY_FAILURE error page
5155 bypass Do not re-write the URL
5157 retry Send the lookup to the helper again
5159 use_configured_response
5160 Use the <quoted-response> as helper response
5164 OPTIONS FOR STORE ID
5165 -----------------------------------------------------------------------------
5168 NAME: store_id_program storeurl_rewrite_program
5170 LOC: Config.Program.store_id
5173 Specify the location of the executable StoreID helper to use.
5174 Since they can perform almost any function there isn't one included.
5176 For each requested URL, the helper will receive one line with the format
5178 [channel-ID <SP>] URL [<SP> extras]<NL>
5181 After processing the request the helper must reply using the following format:
5183 [channel-ID <SP>] result [<SP> kv-pairs]
5185 The result code can be:
5188 Use the StoreID supplied in 'store-id='.
5191 The default is to use HTTP request URL as the store ID.
5194 An internal error occured in the helper, preventing
5195 a result being identified.
5197 In addition to the above kv-pairs Squid also understands the following
5198 optional kv-pairs received from URL rewriters:
5200 Associates a TAG with the client TCP connection.
5201 Please see url_rewrite_program related documentation for this
5204 Helper programs should be prepared to receive and possibly ignore
5205 additional whitespace-separated tokens on each input line.
5207 When using the concurrency= option the protocol is changed by
5208 introducing a query channel tag in front of the request/response.
5209 The query channel tag is a number between 0 and concurrency-1.
5210 This value must be echoed back unchanged to Squid as the first part
5211 of the response relating to its request.
5213 NOTE: when using StoreID refresh_pattern will apply to the StoreID
5214 returned from the helper and not the URL.
5216 WARNING: Wrong StoreID value returned by a careless helper may result
5217 in the wrong cached response returned to the user.
5219 By default, a StoreID helper is not used.
5222 NAME: store_id_extras
5223 TYPE: TokenOrQuotedString
5224 LOC: Config.storeId_extras
5225 DEFAULT: "%>a/%>A %un %>rm myip=%la myport=%lp"
5227 Specifies a string to be append to request line format for the
5228 StoreId helper. "Quoted" format values may contain spaces and
5229 logformat %macros. In theory, any logformat %macro can be used.
5230 In practice, a %macro expands as a dash (-) if the helper request is
5231 sent before the required macro information is available to Squid.
5234 NAME: store_id_children storeurl_rewrite_children
5235 TYPE: HelperChildConfig
5236 DEFAULT: 20 startup=0 idle=1 concurrency=0
5237 LOC: Config.storeIdChildren
5239 The maximum number of StoreID helper processes to spawn. If you limit
5240 it too few Squid will have to wait for them to process a backlog of
5241 requests, slowing it down. If you allow too many they will use RAM
5242 and other system resources noticably.
5244 The startup= and idle= options allow some measure of skew in your
5249 Sets a minimum of how many processes are to be spawned when Squid
5250 starts or reconfigures. When set to zero the first request will
5251 cause spawning of the first child process to handle it.
5253 Starting too few will cause an initial slowdown in traffic as Squid
5254 attempts to simultaneously spawn enough processes to cope.
5258 Sets a minimum of how many processes Squid is to try and keep available
5259 at all times. When traffic begins to rise above what the existing
5260 processes can handle this many more will be spawned up to the maximum
5261 configured. A minimum setting of 1 is required.
5265 The number of requests each storeID helper can handle in
5266 parallel. Defaults to 0 which indicates the helper
5267 is a old-style single threaded program.
5269 When this directive is set to a value >= 1 then the protocol
5270 used to communicate with the helper is modified to include
5271 an ID in front of the request/response. The ID from the request
5272 must be echoed back with the response to that request.
5276 Sets the maximum number of queued requests.
5277 If the queued requests exceed queue size and store_id_bypass
5278 configuration option is set, then storeID helper is bypassed. Otherwise,
5279 if overloading persists squid may abort its operation.
5280 The default value is set to 2*numberofchildren.
5283 NAME: store_id_access storeurl_rewrite_access
5286 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
5287 LOC: Config.accessList.store_id
5289 If defined, this access list specifies which requests are
5290 sent to the StoreID processes. By default all requests
5293 This clause supports both fast and slow acl types.
5294 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5297 NAME: store_id_bypass storeurl_rewrite_bypass
5299 LOC: Config.onoff.store_id_bypass
5302 When this is 'on', a request will not go through the
5303 helper if all helpers are busy. If this is 'off'
5304 and the helper queue grows too large, Squid will exit
5305 with a FATAL error and ask you to increase the number of
5306 helpers. You should only enable this if the helperss
5307 are not critical to your caching system. If you use
5308 helpers for critical caching components, and you enable this
5309 option, users may not get objects from cache.
5310 This options sets default queue-size option of the store_id_children
5315 OPTIONS FOR TUNING THE CACHE
5316 -----------------------------------------------------------------------------
5319 NAME: cache no_cache
5322 DEFAULT_DOC: By default, this directive is unused and has no effect.
5323 LOC: Config.accessList.noCache
5325 Requests denied by this directive will not be served from the cache
5326 and their responses will not be stored in the cache. This directive
5327 has no effect on other transactions and on already cached responses.
5329 This clause supports both fast and slow acl types.
5330 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5332 This and the two other similar caching directives listed below are
5333 checked at different transaction processing stages, have different
5334 access to response information, affect different cache operations,
5335 and differ in slow ACLs support:
5337 * cache: Checked before Squid makes a hit/miss determination.
5338 No access to reply information!
5339 Denies both serving a hit and storing a miss.
5340 Supports both fast and slow ACLs.
5341 * send_hit: Checked after a hit was detected.
5342 Has access to reply (hit) information.
5343 Denies serving a hit only.
5344 Supports fast ACLs only.
5345 * store_miss: Checked before storing a cachable miss.
5346 Has access to reply (miss) information.
5347 Denies storing a miss only.
5348 Supports fast ACLs only.
5350 If you are not sure which of the three directives to use, apply the
5351 following decision logic:
5353 * If your ACL(s) are of slow type _and_ need response info, redesign.
5354 Squid does not support that particular combination at this time.
5356 * If your directive ACL(s) are of slow type, use "cache"; and/or
5357 * if your directive ACL(s) need no response info, use "cache".
5359 * If you do not want the response cached, use store_miss; and/or
5360 * if you do not want a hit on a cached response, use send_hit.
5366 DEFAULT_DOC: By default, this directive is unused and has no effect.
5367 LOC: Config.accessList.sendHit
5369 Responses denied by this directive will not be served from the cache
5370 (but may still be cached, see store_miss). This directive has no
5371 effect on the responses it allows and on the cached objects.
5373 Please see the "cache" directive for a summary of differences among
5374 store_miss, send_hit, and cache directives.
5376 Unlike the "cache" directive, send_hit only supports fast acl
5377 types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5381 # apply custom Store ID mapping to some URLs
5382 acl MapMe dstdomain .c.example.com
5383 store_id_program ...
5384 store_id_access allow MapMe
5386 # but prevent caching of special responses
5387 # such as 302 redirects that cause StoreID loops
5388 acl Ordinary http_status 200-299
5389 store_miss deny MapMe !Ordinary
5391 # and do not serve any previously stored special responses
5392 # from the cache (in case they were already cached before
5393 # the above store_miss rule was in effect).
5394 send_hit deny MapMe !Ordinary
5400 DEFAULT_DOC: By default, this directive is unused and has no effect.
5401 LOC: Config.accessList.storeMiss
5403 Responses denied by this directive will not be cached (but may still
5404 be served from the cache, see send_hit). This directive has no
5405 effect on the responses it allows and on the already cached responses.
5407 Please see the "cache" directive for a summary of differences among
5408 store_miss, send_hit, and cache directives. See the
5409 send_hit directive for a usage example.
5411 Unlike the "cache" directive, store_miss only supports fast acl
5412 types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5418 LOC: Config.maxStale
5421 This option puts an upper limit on how stale content Squid
5422 will serve from the cache if cache validation fails.
5423 Can be overriden by the refresh_pattern max-stale option.
5426 NAME: refresh_pattern
5427 TYPE: refreshpattern
5431 usage: refresh_pattern [-i] regex min percent max [options]
5433 By default, regular expressions are CASE-SENSITIVE. To make
5434 them case-insensitive, use the -i option.
5436 'Min' is the time (in minutes) an object without an explicit
5437 expiry time should be considered fresh. The recommended
5438 value is 0, any higher values may cause dynamic applications
5439 to be erroneously cached unless the application designer
5440 has taken the appropriate actions.
5442 'Percent' is a percentage of the objects age (time since last
5443 modification age) an object without explicit expiry time
5444 will be considered fresh.
5446 'Max' is an upper limit on how long objects without an explicit
5447 expiry time will be considered fresh.
5449 options: override-expire
5459 override-expire enforces min age even if the server
5460 sent an explicit expiry time (e.g., with the
5461 Expires: header or Cache-Control: max-age). Doing this
5462 VIOLATES the HTTP standard. Enabling this feature
5463 could make you liable for problems which it causes.
5465 Note: override-expire does not enforce staleness - it only extends
5466 freshness / min. If the server returns a Expires time which
5467 is longer than your max time, Squid will still consider
5468 the object fresh for that period of time.
5470 override-lastmod enforces min age even on objects
5471 that were modified recently.
5473 reload-into-ims changes a client no-cache or ``reload''
5474 request for a cached entry into a conditional request using
5475 If-Modified-Since and/or If-None-Match headers, provided the
5476 cached entry has a Last-Modified and/or a strong ETag header.
5477 Doing this VIOLATES the HTTP standard. Enabling this feature
5478 could make you liable for problems which it causes.
5480 ignore-reload ignores a client no-cache or ``reload''
5481 header. Doing this VIOLATES the HTTP standard. Enabling
5482 this feature could make you liable for problems which
5485 ignore-no-store ignores any ``Cache-control: no-store''
5486 headers received from a server. Doing this VIOLATES
5487 the HTTP standard. Enabling this feature could make you
5488 liable for problems which it causes.
5490 ignore-private ignores any ``Cache-control: private''
5491 headers received from a server. Doing this VIOLATES
5492 the HTTP standard. Enabling this feature could make you
5493 liable for problems which it causes.
5495 refresh-ims causes squid to contact the origin server
5496 when a client issues an If-Modified-Since request. This
5497 ensures that the client will receive an updated version
5498 if one is available.
5500 store-stale stores responses even if they don't have explicit
5501 freshness or a validator (i.e., Last-Modified or an ETag)
5502 present, or if they're already stale. By default, Squid will
5503 not cache such responses because they usually can't be
5504 reused. Note that such responses will be stale by default.
5506 max-stale=NN provide a maximum staleness factor. Squid won't
5507 serve objects more stale than this even if it failed to
5508 validate the object. Default: use the max_stale global limit.
5510 Basically a cached object is:
5512 FRESH if expires < now, else STALE
5514 FRESH if lm-factor < percent, else STALE
5518 The refresh_pattern lines are checked in the order listed here.
5519 The first entry which matches is used. If none of the entries
5520 match the default will be used.
5522 Note, you must uncomment all the default lines if you want
5523 to change one. The default setting is only active if none is
5529 # Add any of your own refresh_pattern entries above these.
5531 refresh_pattern ^ftp: 1440 20% 10080
5532 refresh_pattern ^gopher: 1440 0% 1440
5533 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0
5534 refresh_pattern . 0 20% 4320
5538 NAME: quick_abort_min
5542 LOC: Config.quickAbort.min
5545 NAME: quick_abort_max
5549 LOC: Config.quickAbort.max
5552 NAME: quick_abort_pct
5556 LOC: Config.quickAbort.pct
5558 The cache by default continues downloading aborted requests
5559 which are almost completed (less than 16 KB remaining). This
5560 may be undesirable on slow (e.g. SLIP) links and/or very busy
5561 caches. Impatient users may tie up file descriptors and
5562 bandwidth by repeatedly requesting and immediately aborting
5565 When the user aborts a request, Squid will check the
5566 quick_abort values to the amount of data transferred until
5569 If the transfer has less than 'quick_abort_min' KB remaining,
5570 it will finish the retrieval.
5572 If the transfer has more than 'quick_abort_max' KB remaining,
5573 it will abort the retrieval.
5575 If more than 'quick_abort_pct' of the transfer has completed,
5576 it will finish the retrieval.
5578 If you do not want any retrieval to continue after the client
5579 has aborted, set both 'quick_abort_min' and 'quick_abort_max'
5582 If you want retrievals to always continue if they are being
5583 cached set 'quick_abort_min' to '-1 KB'.
5586 NAME: read_ahead_gap
5587 COMMENT: buffer-size
5589 LOC: Config.readAheadGap
5592 The amount of data the cache will buffer ahead of what has been
5593 sent to the client when retrieving an object from another server.
5597 IFDEF: USE_HTTP_VIOLATIONS
5600 LOC: Config.negativeTtl
5603 Set the Default Time-to-Live (TTL) for failed requests.
5604 Certain types of failures (such as "connection refused" and
5605 "404 Not Found") are able to be negatively-cached for a short time.
5606 Modern web servers should provide Expires: header, however if they
5607 do not this can provide a minimum TTL.
5608 The default is not to cache errors with unknown expiry details.
5610 Note that this is different from negative caching of DNS lookups.
5612 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5613 this feature could make you liable for problems which it
5617 NAME: positive_dns_ttl
5620 LOC: Config.positiveDnsTtl
5623 Upper limit on how long Squid will cache positive DNS responses.
5624 Default is 6 hours (360 minutes). This directive must be set
5625 larger than negative_dns_ttl.
5628 NAME: negative_dns_ttl
5631 LOC: Config.negativeDnsTtl
5634 Time-to-Live (TTL) for negative caching of failed DNS lookups.
5635 This also sets the lower cache limit on positive lookups.
5636 Minimum value is 1 second, and it is not recommendable to go
5637 much below 10 seconds.
5640 NAME: range_offset_limit
5641 COMMENT: size [acl acl...]
5643 LOC: Config.rangeOffsetLimit
5646 usage: (size) [units] [[!]aclname]
5648 Sets an upper limit on how far (number of bytes) into the file
5649 a Range request may be to cause Squid to prefetch the whole file.
5650 If beyond this limit, Squid forwards the Range request as it is and
5651 the result is NOT cached.
5653 This is to stop a far ahead range request (lets say start at 17MB)
5654 from making Squid fetch the whole object up to that point before
5655 sending anything to the client.
5657 Multiple range_offset_limit lines may be specified, and they will
5658 be searched from top to bottom on each request until a match is found.
5659 The first match found will be used. If no line matches a request, the
5660 default limit of 0 bytes will be used.
5662 'size' is the limit specified as a number of units.
5664 'units' specifies whether to use bytes, KB, MB, etc.
5665 If no units are specified bytes are assumed.
5667 A size of 0 causes Squid to never fetch more than the
5668 client requested. (default)
5670 A size of 'none' causes Squid to always fetch the object from the
5671 beginning so it may cache the result. (2.0 style)
5673 'aclname' is the name of a defined ACL.
5675 NP: Using 'none' as the byte value here will override any quick_abort settings
5676 that may otherwise apply to the range request. The range request will
5677 be fully fetched from start to finish regardless of the client
5678 actions. This affects bandwidth usage.
5681 NAME: minimum_expiry_time
5684 LOC: Config.minimum_expiry_time
5687 The minimum caching time according to (Expires - Date)
5688 headers Squid honors if the object can't be revalidated.
5689 The default is 60 seconds.
5691 In reverse proxy environments it might be desirable to honor
5692 shorter object lifetimes. It is most likely better to make
5693 your server return a meaningful Last-Modified header however.
5695 In ESI environments where page fragments often have short
5696 lifetimes, this will often be best set to 0.
5699 NAME: store_avg_object_size
5703 LOC: Config.Store.avgObjectSize
5705 Average object size, used to estimate number of objects your
5706 cache can hold. The default is 13 KB.
5708 This is used to pre-seed the cache index memory allocation to
5709 reduce expensive reallocate operations while handling clients
5710 traffic. Too-large values may result in memory allocation during
5711 peak traffic, too-small values will result in wasted memory.
5713 Check the cache manager 'info' report metrics for the real
5714 object sizes seen by your Squid before tuning this.
5717 NAME: store_objects_per_bucket
5720 LOC: Config.Store.objectsPerBucket
5722 Target number of objects per bucket in the store hash table.
5723 Lowering this value increases the total number of buckets and
5724 also the storage maintenance rate. The default is 20.
5729 -----------------------------------------------------------------------------
5732 NAME: request_header_max_size
5736 LOC: Config.maxRequestHeaderSize
5738 This specifies the maximum size for HTTP headers in a request.
5739 Request headers are usually relatively small (about 512 bytes).
5740 Placing a limit on the request header size will catch certain
5741 bugs (for example with persistent connections) and possibly
5742 buffer-overflow or denial-of-service attacks.
5745 NAME: reply_header_max_size
5749 LOC: Config.maxReplyHeaderSize
5751 This specifies the maximum size for HTTP headers in a reply.
5752 Reply headers are usually relatively small (about 512 bytes).
5753 Placing a limit on the reply header size will catch certain
5754 bugs (for example with persistent connections) and possibly
5755 buffer-overflow or denial-of-service attacks.
5758 NAME: request_body_max_size
5762 DEFAULT_DOC: No limit.
5763 LOC: Config.maxRequestBodySize
5765 This specifies the maximum size for an HTTP request body.
5766 In other words, the maximum size of a PUT/POST request.
5767 A user who attempts to send a request with a body larger
5768 than this limit receives an "Invalid Request" error message.
5769 If you set this parameter to a zero (the default), there will
5770 be no limit imposed.
5772 See also client_request_buffer_max_size for an alternative
5773 limitation on client uploads which can be configured.
5776 NAME: client_request_buffer_max_size
5780 LOC: Config.maxRequestBufferSize
5782 This specifies the maximum buffer size of a client request.
5783 It prevents squid eating too much memory when somebody uploads
5788 IFDEF: USE_HTTP_VIOLATIONS
5791 DEFAULT_DOC: Obey RFC 2616.
5792 LOC: Config.accessList.brokenPosts
5794 A list of ACL elements which, if matched, causes Squid to send
5795 an extra CRLF pair after the body of a PUT/POST request.
5797 Some HTTP servers has broken implementations of PUT/POST,
5798 and rely on an extra CRLF pair sent by some WWW clients.
5800 Quote from RFC2616 section 4.1 on this matter:
5802 Note: certain buggy HTTP/1.0 client implementations generate an
5803 extra CRLF's after a POST request. To restate what is explicitly
5804 forbidden by the BNF, an HTTP/1.1 client must not preface or follow
5805 a request with an extra CRLF.
5807 This clause only supports fast acl types.
5808 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5811 acl buggy_server url_regex ^http://....
5812 broken_posts allow buggy_server
5815 NAME: adaptation_uses_indirect_client icap_uses_indirect_client
5818 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_ADAPTATION
5820 LOC: Adaptation::Config::use_indirect_client
5822 Controls whether the indirect client IP address (instead of the direct
5823 client IP address) is passed to adaptation services.
5825 See also: follow_x_forwarded_for adaptation_send_client_ip
5829 IFDEF: USE_HTTP_VIOLATIONS
5833 LOC: Config.onoff.via
5835 If set (default), Squid will include a Via header in requests and
5836 replies as required by RFC2616.
5842 LOC: Config.onoff.ie_refresh
5845 Microsoft Internet Explorer up until version 5.5 Service
5846 Pack 1 has an issue with transparent proxies, wherein it
5847 is impossible to force a refresh. Turning this on provides
5848 a partial fix to the problem, by causing all IMS-REFRESH
5849 requests from older IE versions to check the origin server
5850 for fresh content. This reduces hit ratio by some amount
5851 (~10% in my experience), but allows users to actually get
5852 fresh content when they want it. Note because Squid
5853 cannot tell if the user is using 5.5 or 5.5SP1, the behavior
5854 of 5.5 is unchanged from old versions of Squid (i.e. a
5855 forced refresh is impossible). Newer versions of IE will,
5856 hopefully, continue to have the new behavior and will be
5857 handled based on that assumption. This option defaults to
5858 the old Squid behavior, which is better for hit ratios but
5859 worse for clients using IE, if they need to be able to
5860 force fresh content.
5863 NAME: vary_ignore_expire
5866 LOC: Config.onoff.vary_ignore_expire
5869 Many HTTP servers supporting Vary gives such objects
5870 immediate expiry time with no cache-control header
5871 when requested by a HTTP/1.0 client. This option
5872 enables Squid to ignore such expiry times until
5873 HTTP/1.1 is fully implemented.
5875 WARNING: If turned on this may eventually cause some
5876 varying objects not intended for caching to get cached.
5879 NAME: request_entities
5881 LOC: Config.onoff.request_entities
5884 Squid defaults to deny GET and HEAD requests with request entities,
5885 as the meaning of such requests are undefined in the HTTP standard
5886 even if not explicitly forbidden.
5888 Set this directive to on if you have clients which insists
5889 on sending request entities in GET or HEAD requests. But be warned
5890 that there is server software (both proxies and web servers) which
5891 can fail to properly process this kind of request which may make you
5892 vulnerable to cache pollution attacks if enabled.
5895 NAME: request_header_access
5896 IFDEF: USE_HTTP_VIOLATIONS
5897 TYPE: http_header_access
5898 LOC: Config.request_header_access
5900 DEFAULT_DOC: No limits.
5902 Usage: request_header_access header_name allow|deny [!]aclname ...
5904 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5905 this feature could make you liable for problems which it
5908 This option replaces the old 'anonymize_headers' and the
5909 older 'http_anonymizer' option with something that is much
5910 more configurable. A list of ACLs for each header name allows
5911 removal of specific header fields under specific conditions.
5913 This option only applies to outgoing HTTP request headers (i.e.,
5914 headers sent by Squid to the next HTTP hop such as a cache peer
5915 or an origin server). The option has no effect during cache hit
5916 detection. The equivalent adaptation vectoring point in ICAP
5917 terminology is post-cache REQMOD.
5919 The option is applied to individual outgoing request header
5920 fields. For each request header field F, Squid uses the first
5921 qualifying sets of request_header_access rules:
5923 1. Rules with header_name equal to F's name.
5924 2. Rules with header_name 'Other', provided F's name is not
5925 on the hard-coded list of commonly used HTTP header names.
5926 3. Rules with header_name 'All'.
5928 Within that qualifying rule set, rule ACLs are checked as usual.
5929 If ACLs of an "allow" rule match, the header field is allowed to
5930 go through as is. If ACLs of a "deny" rule match, the header is
5931 removed and request_header_replace is then checked to identify
5932 if the removed header has a replacement. If no rules within the
5933 set have matching ACLs, the header field is left as is.
5935 For example, to achieve the same behavior as the old
5936 'http_anonymizer standard' option, you should use:
5938 request_header_access From deny all
5939 request_header_access Referer deny all
5940 request_header_access User-Agent deny all
5942 Or, to reproduce the old 'http_anonymizer paranoid' feature
5945 request_header_access Authorization allow all
5946 request_header_access Proxy-Authorization allow all
5947 request_header_access Cache-Control allow all
5948 request_header_access Content-Length allow all
5949 request_header_access Content-Type allow all
5950 request_header_access Date allow all
5951 request_header_access Host allow all
5952 request_header_access If-Modified-Since allow all
5953 request_header_access Pragma allow all
5954 request_header_access Accept allow all
5955 request_header_access Accept-Charset allow all
5956 request_header_access Accept-Encoding allow all
5957 request_header_access Accept-Language allow all
5958 request_header_access Connection allow all
5959 request_header_access All deny all
5961 HTTP reply headers are controlled with the reply_header_access directive.
5963 By default, all headers are allowed (no anonymizing is performed).
5966 NAME: reply_header_access
5967 IFDEF: USE_HTTP_VIOLATIONS
5968 TYPE: http_header_access
5969 LOC: Config.reply_header_access
5971 DEFAULT_DOC: No limits.
5973 Usage: reply_header_access header_name allow|deny [!]aclname ...
5975 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5976 this feature could make you liable for problems which it
5979 This option only applies to reply headers, i.e., from the
5980 server to the client.
5982 This is the same as request_header_access, but in the other
5983 direction. Please see request_header_access for detailed
5986 For example, to achieve the same behavior as the old
5987 'http_anonymizer standard' option, you should use:
5989 reply_header_access Server deny all
5990 reply_header_access WWW-Authenticate deny all
5991 reply_header_access Link deny all
5993 Or, to reproduce the old 'http_anonymizer paranoid' feature
5996 reply_header_access Allow allow all
5997 reply_header_access WWW-Authenticate allow all
5998 reply_header_access Proxy-Authenticate allow all
5999 reply_header_access Cache-Control allow all
6000 reply_header_access Content-Encoding allow all
6001 reply_header_access Content-Length allow all
6002 reply_header_access Content-Type allow all
6003 reply_header_access Date allow all
6004 reply_header_access Expires allow all
6005 reply_header_access Last-Modified allow all
6006 reply_header_access Location allow all
6007 reply_header_access Pragma allow all
6008 reply_header_access Content-Language allow all
6009 reply_header_access Retry-After allow all
6010 reply_header_access Title allow all
6011 reply_header_access Content-Disposition allow all
6012 reply_header_access Connection allow all
6013 reply_header_access All deny all
6015 HTTP request headers are controlled with the request_header_access directive.
6017 By default, all headers are allowed (no anonymizing is
6021 NAME: request_header_replace header_replace
6022 IFDEF: USE_HTTP_VIOLATIONS
6023 TYPE: http_header_replace
6024 LOC: Config.request_header_access
6027 Usage: request_header_replace header_name message
6028 Example: request_header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
6030 This option allows you to change the contents of headers
6031 denied with request_header_access above, by replacing them
6032 with some fixed string.
6034 This only applies to request headers, not reply headers.
6036 By default, headers are removed if denied.
6039 NAME: reply_header_replace
6040 IFDEF: USE_HTTP_VIOLATIONS
6041 TYPE: http_header_replace
6042 LOC: Config.reply_header_access
6045 Usage: reply_header_replace header_name message
6046 Example: reply_header_replace Server Foo/1.0
6048 This option allows you to change the contents of headers
6049 denied with reply_header_access above, by replacing them
6050 with some fixed string.
6052 This only applies to reply headers, not request headers.
6054 By default, headers are removed if denied.
6057 NAME: request_header_add
6058 TYPE: HeaderWithAclList
6059 LOC: Config.request_header_add
6062 Usage: request_header_add field-name field-value acl1 [acl2] ...
6063 Example: request_header_add X-Client-CA "CA=%ssl::>cert_issuer" all
6065 This option adds header fields to outgoing HTTP requests (i.e.,
6066 request headers sent by Squid to the next HTTP hop such as a
6067 cache peer or an origin server). The option has no effect during
6068 cache hit detection. The equivalent adaptation vectoring point
6069 in ICAP terminology is post-cache REQMOD.
6071 Field-name is a token specifying an HTTP header name. If a
6072 standard HTTP header name is used, Squid does not check whether
6073 the new header conflicts with any existing headers or violates
6074 HTTP rules. If the request to be modified already contains a
6075 field with the same name, the old field is preserved but the
6076 header field values are not merged.
6078 Field-value is either a token or a quoted string. If quoted
6079 string format is used, then the surrounding quotes are removed
6080 while escape sequences and %macros are processed.
6082 In theory, all of the logformat codes can be used as %macros.
6083 However, unlike logging (which happens at the very end of
6084 transaction lifetime), the transaction may not yet have enough
6085 information to expand a macro when the new header value is needed.
6086 And some information may already be available to Squid but not yet
6087 committed where the macro expansion code can access it (report
6088 such instances!). The macro will be expanded into a single dash
6089 ('-') in such cases. Not all macros have been tested.
6091 One or more Squid ACLs may be specified to restrict header
6092 injection to matching requests. As always in squid.conf, all
6093 ACLs in an option ACL list must be satisfied for the insertion
6094 to happen. The request_header_add option supports fast ACLs
6103 This option used to log custom information about the master
6104 transaction. For example, an admin may configure Squid to log
6105 which "user group" the transaction belongs to, where "user group"
6106 will be determined based on a set of ACLs and not [just]
6107 authentication information.
6108 Values of key/value pairs can be logged using %{key}note macros:
6110 note key value acl ...
6111 logformat myFormat ... %{key}note ...
6114 NAME: relaxed_header_parser
6115 COMMENT: on|off|warn
6117 LOC: Config.onoff.relaxed_header_parser
6120 In the default "on" setting Squid accepts certain forms
6121 of non-compliant HTTP messages where it is unambiguous
6122 what the sending application intended even if the message
6123 is not correctly formatted. The messages is then normalized
6124 to the correct form when forwarded by Squid.
6126 If set to "warn" then a warning will be emitted in cache.log
6127 each time such HTTP error is encountered.
6129 If set to "off" then such HTTP errors will cause the request
6130 or response to be rejected.
6133 NAME: collapsed_forwarding
6136 LOC: Config.onoff.collapsed_forwarding
6139 This option controls whether Squid is allowed to merge multiple
6140 potentially cachable requests for the same URI before Squid knows
6141 whether the response is going to be cachable.
6143 This feature is disabled by default: Enabling collapsed forwarding
6144 needlessly delays forwarding requests that look cachable (when they are
6145 collapsed) but then need to be forwarded individually anyway because
6146 they end up being for uncachable content. However, in some cases, such
6147 as accelleration of highly cachable content with periodic or groupped
6148 expiration times, the gains from collapsing [large volumes of
6149 simultenous refresh requests] outweigh losses from such delays.
6154 -----------------------------------------------------------------------------
6157 NAME: forward_timeout
6160 LOC: Config.Timeout.forward
6163 This parameter specifies how long Squid should at most attempt in
6164 finding a forwarding path for the request before giving up.
6167 NAME: connect_timeout
6170 LOC: Config.Timeout.connect
6173 This parameter specifies how long to wait for the TCP connect to
6174 the requested server or peer to complete before Squid should
6175 attempt to find another path where to forward the request.
6178 NAME: peer_connect_timeout
6181 LOC: Config.Timeout.peer_connect
6184 This parameter specifies how long to wait for a pending TCP
6185 connection to a peer cache. The default is 30 seconds. You
6186 may also set different timeout values for individual neighbors
6187 with the 'connect-timeout' option on a 'cache_peer' line.
6193 LOC: Config.Timeout.read
6196 Applied on peer server connections.
6198 After each successful read(), the timeout will be extended by this
6199 amount. If no data is read again after this amount of time,
6200 the request is aborted and logged with ERR_READ_TIMEOUT.
6202 The default is 15 minutes.
6208 LOC: Config.Timeout.write
6211 This timeout is tracked for all connections that have data
6212 available for writing and are waiting for the socket to become
6213 ready. After each successful write, the timeout is extended by
6214 the configured amount. If Squid has data to write but the
6215 connection is not ready for the configured duration, the
6216 transaction associated with the connection is terminated. The
6217 default is 15 minutes.
6220 NAME: request_timeout
6222 LOC: Config.Timeout.request
6225 How long to wait for complete HTTP request headers after initial
6226 connection establishment.
6229 NAME: request_start_timeout
6231 LOC: Config.Timeout.request_start_timeout
6234 How long to wait for the first request byte after initial
6235 connection establishment.
6238 NAME: client_idle_pconn_timeout persistent_request_timeout
6240 LOC: Config.Timeout.clientIdlePconn
6243 How long to wait for the next HTTP request on a persistent
6244 client connection after the previous request completes.
6247 NAME: ftp_client_idle_timeout
6249 LOC: Config.Timeout.ftpClientIdle
6252 How long to wait for an FTP request on a connection to Squid ftp_port.
6253 Many FTP clients do not deal with idle connection closures well,
6254 necessitating a longer default timeout than client_idle_pconn_timeout
6255 used for incoming HTTP requests.
6258 NAME: client_lifetime
6261 LOC: Config.Timeout.lifetime
6264 The maximum amount of time a client (browser) is allowed to
6265 remain connected to the cache process. This protects the Cache
6266 from having a lot of sockets (and hence file descriptors) tied up
6267 in a CLOSE_WAIT state from remote clients that go away without
6268 properly shutting down (either because of a network failure or
6269 because of a poor client implementation). The default is one
6272 NOTE: The default value is intended to be much larger than any
6273 client would ever need to be connected to your cache. You
6274 should probably change client_lifetime only as a last resort.
6275 If you seem to have many client connections tying up
6276 filedescriptors, we recommend first tuning the read_timeout,
6277 request_timeout, persistent_request_timeout and quick_abort values.
6280 NAME: pconn_lifetime
6283 LOC: Config.Timeout.pconnLifetime
6286 Desired maximum lifetime of a persistent connection.
6287 When set, Squid will close a now-idle persistent connection that
6288 exceeded configured lifetime instead of moving the connection into
6289 the idle connection pool (or equivalent). No effect on ongoing/active
6290 transactions. Connection lifetime is the time period from the
6291 connection acceptance or opening time until "now".
6293 This limit is useful in environments with long-lived connections
6294 where Squid configuration or environmental factors change during a
6295 single connection lifetime. If unrestricted, some connections may
6296 last for hours and even days, ignoring those changes that should
6297 have affected their behavior or their existence.
6299 Currently, a new lifetime value supplied via Squid reconfiguration
6300 has no effect on already idle connections unless they become busy.
6302 When set to '0' this limit is not used.
6305 NAME: half_closed_clients
6307 LOC: Config.onoff.half_closed_clients
6310 Some clients may shutdown the sending side of their TCP
6311 connections, while leaving their receiving sides open. Sometimes,
6312 Squid can not tell the difference between a half-closed and a
6313 fully-closed TCP connection.
6315 By default, Squid will immediately close client connections when
6316 read(2) returns "no more data to read."
6318 Change this option to 'on' and Squid will keep open connections
6319 until a read(2) or write(2) on the socket returns an error.
6320 This may show some benefits for reverse proxies. But if not
6321 it is recommended to leave OFF.
6324 NAME: server_idle_pconn_timeout pconn_timeout
6326 LOC: Config.Timeout.serverIdlePconn
6329 Timeout for idle persistent connections to servers and other
6336 LOC: Ident::TheConfig.timeout
6339 Maximum time to wait for IDENT lookups to complete.
6341 If this is too high, and you enabled IDENT lookups from untrusted
6342 users, you might be susceptible to denial-of-service by having
6343 many ident requests going at once.
6346 NAME: shutdown_lifetime
6349 LOC: Config.shutdownLifetime
6352 When SIGTERM or SIGHUP is received, the cache is put into
6353 "shutdown pending" mode until all active sockets are closed.
6354 This value is the lifetime to set for all open descriptors
6355 during shutdown mode. Any active clients after this many
6356 seconds will receive a 'timeout' message.
6360 ADMINISTRATIVE PARAMETERS
6361 -----------------------------------------------------------------------------
6367 LOC: Config.adminEmail
6369 Email-address of local cache manager who will receive
6370 mail if the cache dies. The default is "webmaster".
6376 LOC: Config.EmailFrom
6378 From: email-address for mail sent when the cache dies.
6379 The default is to use 'squid@unique_hostname'.
6381 See also: unique_hostname directive.
6387 LOC: Config.EmailProgram
6389 Email program used to send mail if the cache dies.
6390 The default is "mail". The specified program must comply
6391 with the standard Unix mail syntax:
6392 mail-program recipient < mailfile
6394 Optional command line options can be specified.
6397 NAME: cache_effective_user
6399 DEFAULT: @DEFAULT_CACHE_EFFECTIVE_USER@
6400 LOC: Config.effectiveUser
6402 If you start Squid as root, it will change its effective/real
6403 UID/GID to the user specified below. The default is to change
6404 to UID of @DEFAULT_CACHE_EFFECTIVE_USER@.
6405 see also; cache_effective_group
6408 NAME: cache_effective_group
6411 DEFAULT_DOC: Use system group memberships of the cache_effective_user account
6412 LOC: Config.effectiveGroup
6414 Squid sets the GID to the effective user's default group ID
6415 (taken from the password file) and supplementary group list
6416 from the groups membership.
6418 If you want Squid to run with a specific GID regardless of
6419 the group memberships of the effective user then set this
6420 to the group (or GID) you want Squid to run as. When set
6421 all other group privileges of the effective user are ignored
6422 and only this GID is effective. If Squid is not started as
6423 root the user starting Squid MUST be member of the specified
6426 This option is not recommended by the Squid Team.
6427 Our preference is for administrators to configure a secure
6428 user account for squid with UID/GID matching system policies.
6431 NAME: httpd_suppress_version_string
6435 LOC: Config.onoff.httpd_suppress_version_string
6437 Suppress Squid version string info in HTTP headers and HTML error pages.
6440 NAME: visible_hostname
6442 LOC: Config.visibleHostname
6444 DEFAULT_DOC: Automatically detect the system host name
6446 If you want to present a special hostname in error messages, etc,
6447 define this. Otherwise, the return value of gethostname()
6448 will be used. If you have multiple caches in a cluster and
6449 get errors about IP-forwarding you must set them to have individual
6450 names with this setting.
6453 NAME: unique_hostname
6455 LOC: Config.uniqueHostname
6457 DEFAULT_DOC: Copy the value from visible_hostname
6459 If you want to have multiple machines with the same
6460 'visible_hostname' you must give each machine a different
6461 'unique_hostname' so forwarding loops can be detected.
6464 NAME: hostname_aliases
6466 LOC: Config.hostnameAliases
6469 A list of other DNS names your cache has.
6477 Minimum umask which should be enforced while the proxy
6478 is running, in addition to the umask set at startup.
6480 For a traditional octal representation of umasks, start
6485 OPTIONS FOR THE CACHE REGISTRATION SERVICE
6486 -----------------------------------------------------------------------------
6488 This section contains parameters for the (optional) cache
6489 announcement service. This service is provided to help
6490 cache administrators locate one another in order to join or
6491 create cache hierarchies.
6493 An 'announcement' message is sent (via UDP) to the registration
6494 service by Squid. By default, the announcement message is NOT
6495 SENT unless you enable it with 'announce_period' below.
6497 The announcement message includes your hostname, plus the
6498 following information from this configuration file:
6504 All current information is processed regularly and made
6505 available on the Web at http://www.ircache.net/Cache/Tracker/.
6508 NAME: announce_period
6510 LOC: Config.Announce.period
6512 DEFAULT_DOC: Announcement messages disabled.
6514 This is how frequently to send cache announcements.
6516 To enable announcing your cache, just set an announce period.
6519 announce_period 1 day
6524 DEFAULT: tracker.ircache.net
6525 LOC: Config.Announce.host
6527 Set the hostname where announce registration messages will be sent.
6529 See also announce_port and announce_file
6535 LOC: Config.Announce.file
6537 The contents of this file will be included in the announce
6538 registration messages.
6544 LOC: Config.Announce.port
6546 Set the port where announce registration messages will be sent.
6548 See also announce_host and announce_file
6552 HTTPD-ACCELERATOR OPTIONS
6553 -----------------------------------------------------------------------------
6556 NAME: httpd_accel_surrogate_id
6559 DEFAULT_DOC: visible_hostname is used if no specific ID is set.
6560 LOC: Config.Accel.surrogate_id
6562 Surrogates (http://www.esi.org/architecture_spec_1.0.html)
6563 need an identification token to allow control targeting. Because
6564 a farm of surrogates may all perform the same tasks, they may share
6565 an identification token.
6568 NAME: http_accel_surrogate_remote
6572 LOC: Config.onoff.surrogate_is_remote
6574 Remote surrogates (such as those in a CDN) honour the header
6575 "Surrogate-Control: no-store-remote".
6577 Set this to on to have squid behave as a remote surrogate.
6581 IFDEF: USE_SQUID_ESI
6582 COMMENT: libxml2|expat|custom
6584 LOC: ESIParser::Type
6587 ESI markup is not strictly XML compatible. The custom ESI parser
6588 will give higher performance, but cannot handle non ASCII character
6593 DELAY POOL PARAMETERS
6594 -----------------------------------------------------------------------------
6598 TYPE: delay_pool_count
6600 IFDEF: USE_DELAY_POOLS
6603 This represents the number of delay pools to be used. For example,
6604 if you have one class 2 delay pool and one class 3 delays pool, you
6605 have a total of 2 delay pools.
6607 See also delay_parameters, delay_class, delay_access for pool
6608 configuration details.
6612 TYPE: delay_pool_class
6614 IFDEF: USE_DELAY_POOLS
6617 This defines the class of each delay pool. There must be exactly one
6618 delay_class line for each delay pool. For example, to define two
6619 delay pools, one of class 2 and one of class 3, the settings above
6623 delay_pools 4 # 4 delay pools
6624 delay_class 1 2 # pool 1 is a class 2 pool
6625 delay_class 2 3 # pool 2 is a class 3 pool
6626 delay_class 3 4 # pool 3 is a class 4 pool
6627 delay_class 4 5 # pool 4 is a class 5 pool
6629 The delay pool classes are:
6631 class 1 Everything is limited by a single aggregate
6634 class 2 Everything is limited by a single aggregate
6635 bucket as well as an "individual" bucket chosen
6636 from bits 25 through 32 of the IPv4 address.
6638 class 3 Everything is limited by a single aggregate
6639 bucket as well as a "network" bucket chosen
6640 from bits 17 through 24 of the IP address and a
6641 "individual" bucket chosen from bits 17 through
6642 32 of the IPv4 address.
6644 class 4 Everything in a class 3 delay pool, with an
6645 additional limit on a per user basis. This
6646 only takes effect if the username is established
6647 in advance - by forcing authentication in your
6650 class 5 Requests are grouped according their tag (see
6651 external_acl's tag= reply).
6654 Each pool also requires a delay_parameters directive to configure the pool size
6655 and speed limits used whenever the pool is applied to a request. Along with
6656 a set of delay_access directives to determine when it is used.
6658 NOTE: If an IP address is a.b.c.d
6659 -> bits 25 through 32 are "d"
6660 -> bits 17 through 24 are "c"
6661 -> bits 17 through 32 are "c * 256 + d"
6663 NOTE-2: Due to the use of bitmasks in class 2,3,4 pools they only apply to
6664 IPv4 traffic. Class 1 and 5 pools may be used with IPv6 traffic.
6666 This clause only supports fast acl types.
6667 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6669 See also delay_parameters and delay_access.
6673 TYPE: delay_pool_access
6675 DEFAULT_DOC: Deny using the pool, unless allow rules exist in squid.conf for the pool.
6676 IFDEF: USE_DELAY_POOLS
6679 This is used to determine which delay pool a request falls into.
6681 delay_access is sorted per pool and the matching starts with pool 1,
6682 then pool 2, ..., and finally pool N. The first delay pool where the
6683 request is allowed is selected for the request. If it does not allow
6684 the request to any pool then the request is not delayed (default).
6686 For example, if you want some_big_clients in delay
6687 pool 1 and lotsa_little_clients in delay pool 2:
6689 delay_access 1 allow some_big_clients
6690 delay_access 1 deny all
6691 delay_access 2 allow lotsa_little_clients
6692 delay_access 2 deny all
6693 delay_access 3 allow authenticated_clients
6695 See also delay_parameters and delay_class.
6699 NAME: delay_parameters
6700 TYPE: delay_pool_rates
6702 IFDEF: USE_DELAY_POOLS
6705 This defines the parameters for a delay pool. Each delay pool has
6706 a number of "buckets" associated with it, as explained in the
6707 description of delay_class.
6709 For a class 1 delay pool, the syntax is:
6711 delay_parameters pool aggregate
6713 For a class 2 delay pool:
6715 delay_parameters pool aggregate individual
6717 For a class 3 delay pool:
6719 delay_parameters pool aggregate network individual
6721 For a class 4 delay pool:
6723 delay_parameters pool aggregate network individual user
6725 For a class 5 delay pool:
6727 delay_parameters pool tagrate
6729 The option variables are:
6731 pool a pool number - ie, a number between 1 and the
6732 number specified in delay_pools as used in
6735 aggregate the speed limit parameters for the aggregate bucket
6738 individual the speed limit parameters for the individual
6739 buckets (class 2, 3).
6741 network the speed limit parameters for the network buckets
6744 user the speed limit parameters for the user buckets
6747 tagrate the speed limit parameters for the tag buckets
6750 A pair of delay parameters is written restore/maximum, where restore is
6751 the number of bytes (not bits - modem and network speeds are usually
6752 quoted in bits) per second placed into the bucket, and maximum is the
6753 maximum number of bytes which can be in the bucket at any time.
6755 There must be one delay_parameters line for each delay pool.
6758 For example, if delay pool number 1 is a class 2 delay pool as in the
6759 above example, and is being used to strictly limit each host to 64Kbit/sec
6760 (plus overheads), with no overall limit, the line is:
6762 delay_parameters 1 none 8000/8000
6764 Note that 8 x 8000 KByte/sec -> 64Kbit/sec.
6766 Note that the word 'none' is used to represent no limit.
6769 And, if delay pool number 2 is a class 3 delay pool as in the above
6770 example, and you want to limit it to a total of 256Kbit/sec (strict limit)
6771 with each 8-bit network permitted 64Kbit/sec (strict limit) and each
6772 individual host permitted 4800bit/sec with a bucket maximum size of 64Kbits
6773 to permit a decent web page to be downloaded at a decent speed
6774 (if the network is not being limited due to overuse) but slow down
6775 large downloads more significantly:
6777 delay_parameters 2 32000/32000 8000/8000 600/8000
6779 Note that 8 x 32000 KByte/sec -> 256Kbit/sec.
6780 8 x 8000 KByte/sec -> 64Kbit/sec.
6781 8 x 600 Byte/sec -> 4800bit/sec.
6784 Finally, for a class 4 delay pool as in the example - each user will
6785 be limited to 128Kbits/sec no matter how many workstations they are logged into.:
6787 delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000
6790 See also delay_class and delay_access.
6794 NAME: delay_initial_bucket_level
6795 COMMENT: (percent, 0-100)
6798 IFDEF: USE_DELAY_POOLS
6799 LOC: Config.Delay.initial
6801 The initial bucket percentage is used to determine how much is put
6802 in each bucket when squid starts, is reconfigured, or first notices
6803 a host accessing it (in class 2 and class 3, individual hosts and
6804 networks only have buckets associated with them once they have been
6809 CLIENT DELAY POOL PARAMETERS
6810 -----------------------------------------------------------------------------
6813 NAME: client_delay_pools
6814 TYPE: client_delay_pool_count
6816 IFDEF: USE_DELAY_POOLS
6817 LOC: Config.ClientDelay
6819 This option specifies the number of client delay pools used. It must
6820 preceed other client_delay_* options.
6823 client_delay_pools 2
6825 See also client_delay_parameters and client_delay_access.
6828 NAME: client_delay_initial_bucket_level
6829 COMMENT: (percent, 0-no_limit)
6832 IFDEF: USE_DELAY_POOLS
6833 LOC: Config.ClientDelay.initial
6835 This option determines the initial bucket size as a percentage of
6836 max_bucket_size from client_delay_parameters. Buckets are created
6837 at the time of the "first" connection from the matching IP. Idle
6838 buckets are periodically deleted up.
6840 You can specify more than 100 percent but note that such "oversized"
6841 buckets are not refilled until their size goes down to max_bucket_size
6842 from client_delay_parameters.
6845 client_delay_initial_bucket_level 50
6848 NAME: client_delay_parameters
6849 TYPE: client_delay_pool_rates
6851 IFDEF: USE_DELAY_POOLS
6852 LOC: Config.ClientDelay
6855 This option configures client-side bandwidth limits using the
6858 client_delay_parameters pool speed_limit max_bucket_size
6860 pool is an integer ID used for client_delay_access matching.
6862 speed_limit is bytes added to the bucket per second.
6864 max_bucket_size is the maximum size of a bucket, enforced after any
6865 speed_limit additions.
6867 Please see the delay_parameters option for more information and
6871 client_delay_parameters 1 1024 2048
6872 client_delay_parameters 2 51200 16384
6874 See also client_delay_access.
6878 NAME: client_delay_access
6879 TYPE: client_delay_pool_access
6881 DEFAULT_DOC: Deny use of the pool, unless allow rules exist in squid.conf for the pool.
6882 IFDEF: USE_DELAY_POOLS
6883 LOC: Config.ClientDelay
6885 This option determines the client-side delay pool for the
6888 client_delay_access pool_ID allow|deny acl_name
6890 All client_delay_access options are checked in their pool ID
6891 order, starting with pool 1. The first checked pool with allowed
6892 request is selected for the request. If no ACL matches or there
6893 are no client_delay_access options, the request bandwidth is not
6896 The ACL-selected pool is then used to find the
6897 client_delay_parameters for the request. Client-side pools are
6898 not used to aggregate clients. Clients are always aggregated
6899 based on their source IP addresses (one bucket per source IP).
6901 This clause only supports fast acl types.
6902 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6903 Additionally, only the client TCP connection details are available.
6904 ACLs testing HTTP properties will not work.
6906 Please see delay_access for more examples.
6909 client_delay_access 1 allow low_rate_network
6910 client_delay_access 2 allow vips_network
6913 See also client_delay_parameters and client_delay_pools.
6917 WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS
6918 -----------------------------------------------------------------------------
6923 LOC: Config.Wccp.router
6925 DEFAULT_DOC: WCCP disabled.
6928 Use this option to define your WCCP ``home'' router for
6931 wccp_router supports a single WCCP(v1) router
6933 wccp2_router supports multiple WCCPv2 routers
6935 only one of the two may be used at the same time and defines
6936 which version of WCCP to use.
6940 TYPE: IpAddress_list
6941 LOC: Config.Wccp2.router
6943 DEFAULT_DOC: WCCPv2 disabled.
6946 Use this option to define your WCCP ``home'' router for
6949 wccp_router supports a single WCCP(v1) router
6951 wccp2_router supports multiple WCCPv2 routers
6953 only one of the two may be used at the same time and defines
6954 which version of WCCP to use.
6959 LOC: Config.Wccp.version
6963 This directive is only relevant if you need to set up WCCP(v1)
6964 to some very old and end-of-life Cisco routers. In all other
6965 setups it must be left unset or at the default setting.
6966 It defines an internal version in the WCCP(v1) protocol,
6967 with version 4 being the officially documented protocol.
6969 According to some users, Cisco IOS 11.2 and earlier only
6970 support WCCP version 3. If you're using that or an earlier
6971 version of IOS, you may need to change this value to 3, otherwise
6972 do not specify this parameter.
6975 NAME: wccp2_rebuild_wait
6977 LOC: Config.Wccp2.rebuildwait
6981 If this is enabled Squid will wait for the cache dir rebuild to finish
6982 before sending the first wccp2 HereIAm packet
6985 NAME: wccp2_forwarding_method
6987 LOC: Config.Wccp2.forwarding_method
6991 WCCP2 allows the setting of forwarding methods between the
6992 router/switch and the cache. Valid values are as follows:
6994 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
6995 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
6997 Currently (as of IOS 12.4) cisco routers only support GRE.
6998 Cisco switches only support the L2 redirect assignment method.
7001 NAME: wccp2_return_method
7003 LOC: Config.Wccp2.return_method
7007 WCCP2 allows the setting of return methods between the
7008 router/switch and the cache for packets that the cache
7009 decides not to handle. Valid values are as follows:
7011 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
7012 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
7014 Currently (as of IOS 12.4) cisco routers only support GRE.
7015 Cisco switches only support the L2 redirect assignment.
7017 If the "ip wccp redirect exclude in" command has been
7018 enabled on the cache interface, then it is still safe for
7019 the proxy server to use a l2 redirect method even if this
7020 option is set to GRE.
7023 NAME: wccp2_assignment_method
7025 LOC: Config.Wccp2.assignment_method
7029 WCCP2 allows the setting of methods to assign the WCCP hash
7030 Valid values are as follows:
7032 hash - Hash assignment
7033 mask - Mask assignment
7035 As a general rule, cisco routers support the hash assignment method
7036 and cisco switches support the mask assignment method.
7041 LOC: Config.Wccp2.info
7042 DEFAULT_IF_NONE: standard 0
7043 DEFAULT_DOC: Use the 'web-cache' standard service.
7046 WCCP2 allows for multiple traffic services. There are two
7047 types: "standard" and "dynamic". The standard type defines
7048 one service id - http (id 0). The dynamic service ids can be from
7049 51 to 255 inclusive. In order to use a dynamic service id
7050 one must define the type of traffic to be redirected; this is done
7051 using the wccp2_service_info option.
7053 The "standard" type does not require a wccp2_service_info option,
7054 just specifying the service id will suffice.
7056 MD5 service authentication can be enabled by adding
7057 "password=<password>" to the end of this service declaration.
7061 wccp2_service standard 0 # for the 'web-cache' standard service
7062 wccp2_service dynamic 80 # a dynamic service type which will be
7063 # fleshed out with subsequent options.
7064 wccp2_service standard 0 password=foo
7067 NAME: wccp2_service_info
7068 TYPE: wccp2_service_info
7069 LOC: Config.Wccp2.info
7073 Dynamic WCCPv2 services require further information to define the
7074 traffic you wish to have diverted.
7078 wccp2_service_info <id> protocol=<protocol> flags=<flag>,<flag>..
7079 priority=<priority> ports=<port>,<port>..
7081 The relevant WCCPv2 flags:
7082 + src_ip_hash, dst_ip_hash
7083 + source_port_hash, dst_port_hash
7084 + src_ip_alt_hash, dst_ip_alt_hash
7085 + src_port_alt_hash, dst_port_alt_hash
7088 The port list can be one to eight entries.
7092 wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source
7093 priority=240 ports=80
7095 Note: the service id must have been defined by a previous
7096 'wccp2_service dynamic <id>' entry.
7101 LOC: Config.Wccp2.weight
7105 Each cache server gets assigned a set of the destination
7106 hash proportional to their weight.
7111 LOC: Config.Wccp.address
7113 DEFAULT_DOC: Address selected by the operating system.
7116 Use this option if you require WCCPv2 to use a specific
7119 The default behavior is to not bind to any specific address.
7124 LOC: Config.Wccp2.address
7126 DEFAULT_DOC: Address selected by the operating system.
7129 Use this option if you require WCCP to use a specific
7132 The default behavior is to not bind to any specific address.
7136 PERSISTENT CONNECTION HANDLING
7137 -----------------------------------------------------------------------------
7139 Also see "pconn_timeout" in the TIMEOUTS section
7142 NAME: client_persistent_connections
7144 LOC: Config.onoff.client_pconns
7147 Persistent connection support for clients.
7148 Squid uses persistent connections (when allowed). You can use
7149 this option to disable persistent connections with clients.
7152 NAME: server_persistent_connections
7154 LOC: Config.onoff.server_pconns
7157 Persistent connection support for servers.
7158 Squid uses persistent connections (when allowed). You can use
7159 this option to disable persistent connections with servers.
7162 NAME: persistent_connection_after_error
7164 LOC: Config.onoff.error_pconns
7167 With this directive the use of persistent connections after
7168 HTTP errors can be disabled. Useful if you have clients
7169 who fail to handle errors on persistent connections proper.
7172 NAME: detect_broken_pconn
7174 LOC: Config.onoff.detect_broken_server_pconns
7177 Some servers have been found to incorrectly signal the use
7178 of HTTP/1.0 persistent connections even on replies not
7179 compatible, causing significant delays. This server problem
7180 has mostly been seen on redirects.
7182 By enabling this directive Squid attempts to detect such
7183 broken replies and automatically assume the reply is finished
7184 after 10 seconds timeout.
7188 CACHE DIGEST OPTIONS
7189 -----------------------------------------------------------------------------
7192 NAME: digest_generation
7193 IFDEF: USE_CACHE_DIGESTS
7195 LOC: Config.onoff.digest_generation
7198 This controls whether the server will generate a Cache Digest
7199 of its contents. By default, Cache Digest generation is
7200 enabled if Squid is compiled with --enable-cache-digests defined.
7203 NAME: digest_bits_per_entry
7204 IFDEF: USE_CACHE_DIGESTS
7206 LOC: Config.digest.bits_per_entry
7209 This is the number of bits of the server's Cache Digest which
7210 will be associated with the Digest entry for a given HTTP
7211 Method and URL (public key) combination. The default is 5.
7214 NAME: digest_rebuild_period
7215 IFDEF: USE_CACHE_DIGESTS
7218 LOC: Config.digest.rebuild_period
7221 This is the wait time between Cache Digest rebuilds.
7224 NAME: digest_rewrite_period
7226 IFDEF: USE_CACHE_DIGESTS
7228 LOC: Config.digest.rewrite_period
7231 This is the wait time between Cache Digest writes to
7235 NAME: digest_swapout_chunk_size
7238 IFDEF: USE_CACHE_DIGESTS
7239 LOC: Config.digest.swapout_chunk_size
7242 This is the number of bytes of the Cache Digest to write to
7243 disk at a time. It defaults to 4096 bytes (4KB), the Squid
7247 NAME: digest_rebuild_chunk_percentage
7248 COMMENT: (percent, 0-100)
7249 IFDEF: USE_CACHE_DIGESTS
7251 LOC: Config.digest.rebuild_chunk_percentage
7254 This is the percentage of the Cache Digest to be scanned at a
7255 time. By default it is set to 10% of the Cache Digest.
7260 -----------------------------------------------------------------------------
7265 LOC: Config.Port.snmp
7267 DEFAULT_DOC: SNMP disabled.
7270 The port number where Squid listens for SNMP requests. To enable
7271 SNMP support set this to a suitable port number. Port number
7272 3401 is often used for the Squid SNMP agent. By default it's
7273 set to "0" (disabled)
7281 LOC: Config.accessList.snmp
7283 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
7286 Allowing or denying access to the SNMP port.
7288 All access to the agent is denied by default.
7291 snmp_access allow|deny [!]aclname ...
7293 This clause only supports fast acl types.
7294 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7297 snmp_access allow snmppublic localhost
7298 snmp_access deny all
7301 NAME: snmp_incoming_address
7303 LOC: Config.Addrs.snmp_incoming
7305 DEFAULT_DOC: Accept SNMP packets from all machine interfaces.
7308 Just like 'udp_incoming_address', but for the SNMP port.
7310 snmp_incoming_address is used for the SNMP socket receiving
7311 messages from SNMP agents.
7313 The default snmp_incoming_address is to listen on all
7314 available network interfaces.
7317 NAME: snmp_outgoing_address
7319 LOC: Config.Addrs.snmp_outgoing
7321 DEFAULT_DOC: Use snmp_incoming_address or an address selected by the operating system.
7324 Just like 'udp_outgoing_address', but for the SNMP port.
7326 snmp_outgoing_address is used for SNMP packets returned to SNMP
7329 If snmp_outgoing_address is not set it will use the same socket
7330 as snmp_incoming_address. Only change this if you want to have
7331 SNMP replies sent using another address than where this Squid
7332 listens for SNMP queries.
7334 NOTE, snmp_incoming_address and snmp_outgoing_address can not have
7335 the same value since they both use the same port.
7340 -----------------------------------------------------------------------------
7343 NAME: icp_port udp_port
7346 DEFAULT_DOC: ICP disabled.
7347 LOC: Config.Port.icp
7349 The port number where Squid sends and receives ICP queries to
7350 and from neighbor caches. The standard UDP port for ICP is 3130.
7353 icp_port @DEFAULT_ICP_PORT@
7360 DEFAULT_DOC: HTCP disabled.
7361 LOC: Config.Port.htcp
7363 The port number where Squid sends and receives HTCP queries to
7364 and from neighbor caches. To turn it on you want to set it to
7371 NAME: log_icp_queries
7375 LOC: Config.onoff.log_udp
7377 If set, ICP queries are logged to access.log. You may wish
7378 do disable this if your ICP load is VERY high to speed things
7379 up or to simplify log analysis.
7382 NAME: udp_incoming_address
7384 LOC:Config.Addrs.udp_incoming
7386 DEFAULT_DOC: Accept packets from all machine interfaces.
7388 udp_incoming_address is used for UDP packets received from other
7391 The default behavior is to not bind to any specific address.
7393 Only change this if you want to have all UDP queries received on
7394 a specific interface/address.
7396 NOTE: udp_incoming_address is used by the ICP, HTCP, and DNS
7397 modules. Altering it will affect all of them in the same manner.
7399 see also; udp_outgoing_address
7401 NOTE, udp_incoming_address and udp_outgoing_address can not
7402 have the same value since they both use the same port.
7405 NAME: udp_outgoing_address
7407 LOC: Config.Addrs.udp_outgoing
7409 DEFAULT_DOC: Use udp_incoming_address or an address selected by the operating system.
7411 udp_outgoing_address is used for UDP packets sent out to other
7414 The default behavior is to not bind to any specific address.
7416 Instead it will use the same socket as udp_incoming_address.
7417 Only change this if you want to have UDP queries sent using another
7418 address than where this Squid listens for UDP queries from other
7421 NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS
7422 modules. Altering it will affect all of them in the same manner.
7424 see also; udp_incoming_address
7426 NOTE, udp_incoming_address and udp_outgoing_address can not
7427 have the same value since they both use the same port.
7434 LOC: Config.onoff.icp_hit_stale
7436 If you want to return ICP_HIT for stale cache objects, set this
7437 option to 'on'. If you have sibling relationships with caches
7438 in other administrative domains, this should be 'off'. If you only
7439 have sibling relationships with caches under your control,
7440 it is probably okay to set this to 'on'.
7441 If set to 'on', your siblings should use the option "allow-miss"
7442 on their cache_peer lines for connecting to you.
7445 NAME: minimum_direct_hops
7448 LOC: Config.minDirectHops
7450 If using the ICMP pinging stuff, do direct fetches for sites
7451 which are no more than this many hops away.
7454 NAME: minimum_direct_rtt
7458 LOC: Config.minDirectRtt
7460 If using the ICMP pinging stuff, do direct fetches for sites
7461 which are no more than this many rtt milliseconds away.
7467 LOC: Config.Netdb.low
7469 The low water mark for the ICMP measurement database.
7471 Note: high watermark controlled by netdb_high directive.
7473 These watermarks are counts, not percents. The defaults are
7474 (low) 900 and (high) 1000. When the high water mark is
7475 reached, database entries will be deleted until the low
7482 LOC: Config.Netdb.high
7484 The high water mark for the ICMP measurement database.
7486 Note: low watermark controlled by netdb_low directive.
7488 These watermarks are counts, not percents. The defaults are
7489 (low) 900 and (high) 1000. When the high water mark is
7490 reached, database entries will be deleted until the low
7494 NAME: netdb_ping_period
7496 LOC: Config.Netdb.period
7499 The minimum period for measuring a site. There will be at
7500 least this much delay between successive pings to the same
7501 network. The default is five minutes.
7508 LOC: Config.onoff.query_icmp
7510 If you want to ask your peers to include ICMP data in their ICP
7511 replies, enable this option.
7513 If your peer has configured Squid (during compilation) with
7514 '--enable-icmp' that peer will send ICMP pings to origin server
7515 sites of the URLs it receives. If you enable this option the
7516 ICP replies from that peer will include the ICMP data (if available).
7517 Then, when choosing a parent cache, Squid will choose the parent with
7518 the minimal RTT to the origin server. When this happens, the
7519 hierarchy field of the access.log will be
7520 "CLOSEST_PARENT_MISS". This option is off by default.
7523 NAME: test_reachability
7527 LOC: Config.onoff.test_reachability
7529 When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
7530 instead of ICP_MISS if the target host is NOT in the ICMP
7531 database, or has a zero RTT.
7534 NAME: icp_query_timeout
7537 DEFAULT_DOC: Dynamic detection.
7539 LOC: Config.Timeout.icp_query
7541 Normally Squid will automatically determine an optimal ICP
7542 query timeout value based on the round-trip-time of recent ICP
7543 queries. If you want to override the value determined by
7544 Squid, set this 'icp_query_timeout' to a non-zero value. This
7545 value is specified in MILLISECONDS, so, to use a 2-second
7546 timeout (the old default), you would write:
7548 icp_query_timeout 2000
7551 NAME: maximum_icp_query_timeout
7555 LOC: Config.Timeout.icp_query_max
7557 Normally the ICP query timeout is determined dynamically. But
7558 sometimes it can lead to very large values (say 5 seconds).
7559 Use this option to put an upper limit on the dynamic timeout
7560 value. Do NOT use this option to always use a fixed (instead
7561 of a dynamic) timeout value. To set a fixed timeout see the
7562 'icp_query_timeout' directive.
7565 NAME: minimum_icp_query_timeout
7569 LOC: Config.Timeout.icp_query_min
7571 Normally the ICP query timeout is determined dynamically. But
7572 sometimes it can lead to very small timeouts, even lower than
7573 the normal latency variance on your link due to traffic.
7574 Use this option to put an lower limit on the dynamic timeout
7575 value. Do NOT use this option to always use a fixed (instead
7576 of a dynamic) timeout value. To set a fixed timeout see the
7577 'icp_query_timeout' directive.
7580 NAME: background_ping_rate
7584 LOC: Config.backgroundPingRate
7586 Controls how often the ICP pings are sent to siblings that
7587 have background-ping set.
7591 MULTICAST ICP OPTIONS
7592 -----------------------------------------------------------------------------
7597 LOC: Config.mcast_group_list
7600 This tag specifies a list of multicast groups which your server
7601 should join to receive multicasted ICP queries.
7603 NOTE! Be very careful what you put here! Be sure you
7604 understand the difference between an ICP _query_ and an ICP
7605 _reply_. This option is to be set only if you want to RECEIVE
7606 multicast queries. Do NOT set this option to SEND multicast
7607 ICP (use cache_peer for that). ICP replies are always sent via
7608 unicast, so this option does not affect whether or not you will
7609 receive replies from multicast group members.
7611 You must be very careful to NOT use a multicast address which
7612 is already in use by another group of caches.
7614 If you are unsure about multicast, please read the Multicast
7615 chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
7617 Usage: mcast_groups 239.128.16.128 224.0.1.20
7619 By default, Squid doesn't listen on any multicast groups.
7622 NAME: mcast_miss_addr
7623 IFDEF: MULTICAST_MISS_STREAM
7625 LOC: Config.mcast_miss.addr
7627 DEFAULT_DOC: disabled.
7629 If you enable this option, every "cache miss" URL will
7630 be sent out on the specified multicast address.
7632 Do not enable this option unless you are are absolutely
7633 certain you understand what you are doing.
7636 NAME: mcast_miss_ttl
7637 IFDEF: MULTICAST_MISS_STREAM
7639 LOC: Config.mcast_miss.ttl
7642 This is the time-to-live value for packets multicasted
7643 when multicasting off cache miss URLs is enabled. By
7644 default this is set to 'site scope', i.e. 16.
7647 NAME: mcast_miss_port
7648 IFDEF: MULTICAST_MISS_STREAM
7650 LOC: Config.mcast_miss.port
7653 This is the port number to be used in conjunction with
7657 NAME: mcast_miss_encode_key
7658 IFDEF: MULTICAST_MISS_STREAM
7660 LOC: Config.mcast_miss.encode_key
7661 DEFAULT: XXXXXXXXXXXXXXXX
7663 The URLs that are sent in the multicast miss stream are
7664 encrypted. This is the encryption key.
7667 NAME: mcast_icp_query_timeout
7671 LOC: Config.Timeout.mcast_icp_query
7673 For multicast peers, Squid regularly sends out ICP "probes" to
7674 count how many other peers are listening on the given multicast
7675 address. This value specifies how long Squid should wait to
7676 count all the replies. The default is 2000 msec, or 2
7681 INTERNAL ICON OPTIONS
7682 -----------------------------------------------------------------------------
7685 NAME: icon_directory
7687 LOC: Config.icons.directory
7688 DEFAULT: @DEFAULT_ICON_DIR@
7690 Where the icons are stored. These are normally kept in
7694 NAME: global_internal_static
7696 LOC: Config.onoff.global_internal_static
7699 This directive controls is Squid should intercept all requests for
7700 /squid-internal-static/ no matter which host the URL is requesting
7701 (default on setting), or if nothing special should be done for
7702 such URLs (off setting). The purpose of this directive is to make
7703 icons etc work better in complex cache hierarchies where it may
7704 not always be possible for all corners in the cache mesh to reach
7705 the server generating a directory listing.
7708 NAME: short_icon_urls
7710 LOC: Config.icons.use_short_names
7713 If this is enabled Squid will use short URLs for icons.
7714 If disabled it will revert to the old behavior of including
7715 it's own name and port in the URL.
7717 If you run a complex cache hierarchy with a mix of Squid and
7718 other proxies you may need to disable this directive.
7723 -----------------------------------------------------------------------------
7726 NAME: error_directory
7728 LOC: Config.errorDirectory
7730 DEFAULT_DOC: Send error pages in the clients preferred language
7732 If you wish to create your own versions of the default
7733 error files to customize them to suit your company copy
7734 the error/template files to another directory and point
7737 WARNING: This option will disable multi-language support
7738 on error pages if used.
7740 The squid developers are interested in making squid available in
7741 a wide variety of languages. If you are making translations for a
7742 language that Squid does not currently provide please consider
7743 contributing your translation back to the project.
7744 http://wiki.squid-cache.org/Translations
7746 The squid developers working on translations are happy to supply drop-in
7747 translated error files in exchange for any new language contributions.
7750 NAME: error_default_language
7751 IFDEF: USE_ERR_LOCALES
7753 LOC: Config.errorDefaultLanguage
7755 DEFAULT_DOC: Generate English language pages.
7757 Set the default language which squid will send error pages in
7758 if no existing translation matches the clients language
7761 If unset (default) generic English will be used.
7763 The squid developers are interested in making squid available in
7764 a wide variety of languages. If you are interested in making
7765 translations for any language see the squid wiki for details.
7766 http://wiki.squid-cache.org/Translations
7769 NAME: error_log_languages
7770 IFDEF: USE_ERR_LOCALES
7772 LOC: Config.errorLogMissingLanguages
7775 Log to cache.log what languages users are attempting to
7776 auto-negotiate for translations.
7778 Successful negotiations are not logged. Only failures
7779 have meaning to indicate that Squid may need an upgrade
7780 of its error page translations.
7783 NAME: err_page_stylesheet
7785 LOC: Config.errorStylesheet
7786 DEFAULT: @DEFAULT_CONFIG_DIR@/errorpage.css
7788 CSS Stylesheet to pattern the display of Squid default error pages.
7790 For information on CSS see http://www.w3.org/Style/CSS/
7795 LOC: Config.errHtmlText
7798 HTML text to include in error messages. Make this a "mailto"
7799 URL to your admin address, or maybe just a link to your
7800 organizations Web page.
7802 To include this in your error messages, you must rewrite
7803 the error template files (found in the "errors" directory).
7804 Wherever you want the 'err_html_text' line to appear,
7805 insert a %L tag in the error template file.
7808 NAME: email_err_data
7811 LOC: Config.onoff.emailErrData
7814 If enabled, information about the occurred error will be
7815 included in the mailto links of the ERR pages (if %W is set)
7816 so that the email body contains the data.
7817 Syntax is <A HREF="mailto:%w%W">%w</A>
7822 LOC: Config.denyInfoList
7825 Usage: deny_info err_page_name acl
7826 or deny_info http://... acl
7827 or deny_info TCP_RESET acl
7829 This can be used to return a ERR_ page for requests which
7830 do not pass the 'http_access' rules. Squid remembers the last
7831 acl it evaluated in http_access, and if a 'deny_info' line exists
7832 for that ACL Squid returns a corresponding error page.
7834 The acl is typically the last acl on the http_access deny line which
7835 denied access. The exceptions to this rule are:
7836 - When Squid needs to request authentication credentials. It's then
7837 the first authentication related acl encountered
7838 - When none of the http_access lines matches. It's then the last
7839 acl processed on the last http_access line.
7840 - When the decision to deny access was made by an adaptation service,
7841 the acl name is the corresponding eCAP or ICAP service_name.
7843 NP: If providing your own custom error pages with error_directory
7844 you may also specify them by your custom file name:
7845 Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
7847 By defaut Squid will send "403 Forbidden". A different 4xx or 5xx
7848 may be specified by prefixing the file name with the code and a colon.
7849 e.g. 404:ERR_CUSTOM_ACCESS_DENIED
7851 Alternatively you can tell Squid to reset the TCP connection
7852 by specifying TCP_RESET.
7854 Or you can specify an error URL or URL pattern. The browsers will
7855 get redirected to the specified URL after formatting tags have
7856 been replaced. Redirect will be done with 302 or 307 according to
7857 HTTP/1.1 specs. A different 3xx code may be specified by prefixing
7858 the URL. e.g. 303:http://example.com/
7861 %a - username (if available. Password NOT included)
7864 %E - Error description
7866 %H - Request domain name
7867 %i - Client IP Address
7869 %o - Message result from external ACL helper
7870 %p - Request Port number
7871 %P - Request Protocol name
7872 %R - Request URL path
7873 %T - Timestamp in RFC 1123 format
7874 %U - Full canonical URL from client
7875 (HTTPS URLs terminate with *)
7876 %u - Full canonical URL from client
7877 %w - Admin email from squid.conf
7879 %% - Literal percent (%) code
7884 OPTIONS INFLUENCING REQUEST FORWARDING
7885 -----------------------------------------------------------------------------
7888 NAME: nonhierarchical_direct
7890 LOC: Config.onoff.nonhierarchical_direct
7893 By default, Squid will send any non-hierarchical requests
7894 (not cacheable request type) direct to origin servers.
7896 When this is set to "off", Squid will prefer to send these
7897 requests to parents.
7899 Note that in most configurations, by turning this off you will only
7900 add latency to these request without any improvement in global hit
7903 This option only sets a preference. If the parent is unavailable a
7904 direct connection to the origin server may still be attempted. To
7905 completely prevent direct connections use never_direct.
7910 LOC: Config.onoff.prefer_direct
7913 Normally Squid tries to use parents for most requests. If you for some
7914 reason like it to first try going direct and only use a parent if
7915 going direct fails set this to on.
7917 By combining nonhierarchical_direct off and prefer_direct on you
7918 can set up Squid to use a parent as a backup path if going direct
7921 Note: If you want Squid to use parents for all requests see
7922 the never_direct directive. prefer_direct only modifies how Squid
7923 acts on cacheable requests.
7926 NAME: cache_miss_revalidate
7930 LOC: Config.onoff.cache_miss_revalidate
7932 RFC 7232 defines a conditional request mechanism to prevent
7933 response objects being unnecessarily transferred over the network.
7934 If that mechanism is used by the client and a cache MISS occurs
7935 it can prevent new cache entries being created.
7937 This option determines whether Squid on cache MISS will pass the
7938 client revalidation request to the server or tries to fetch new
7939 content for caching. It can be useful while the cache is mostly
7940 empty to more quickly have the cache populated by generating
7941 non-conditional GETs.
7943 When set to 'on' (default), Squid will pass all client If-* headers
7944 to the server. This permits server responses without a cacheable
7945 payload to be delivered and on MISS no new cache entry is created.
7947 When set to 'off' and if the request is cacheable, Squid will
7948 remove the clients If-Modified-Since and If-None-Match headers from
7949 the request sent to the server. This requests a 200 status response
7950 from the server to create a new cache entry with.
7955 LOC: Config.accessList.AlwaysDirect
7957 DEFAULT_DOC: Prevent any cache_peer being used for this request.
7959 Usage: always_direct allow|deny [!]aclname ...
7961 Here you can use ACL elements to specify requests which should
7962 ALWAYS be forwarded by Squid to the origin servers without using
7963 any peers. For example, to always directly forward requests for
7964 local servers ignoring any parents or siblings you may have use
7967 acl local-servers dstdomain my.domain.net
7968 always_direct allow local-servers
7970 To always forward FTP requests directly, use
7973 always_direct allow FTP
7975 NOTE: There is a similar, but opposite option named
7976 'never_direct'. You need to be aware that "always_direct deny
7977 foo" is NOT the same thing as "never_direct allow foo". You
7978 may need to use a deny rule to exclude a more-specific case of
7979 some other rule. Example:
7981 acl local-external dstdomain external.foo.net
7982 acl local-servers dstdomain .foo.net
7983 always_direct deny local-external
7984 always_direct allow local-servers
7986 NOTE: If your goal is to make the client forward the request
7987 directly to the origin server bypassing Squid then this needs
7988 to be done in the client configuration. Squid configuration
7989 can only tell Squid how Squid should fetch the object.
7991 NOTE: This directive is not related to caching. The replies
7992 is cached as usual even if you use always_direct. To not cache
7993 the replies see the 'cache' directive.
7995 This clause supports both fast and slow acl types.
7996 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
8001 LOC: Config.accessList.NeverDirect
8003 DEFAULT_DOC: Allow DNS results to be used for this request.
8005 Usage: never_direct allow|deny [!]aclname ...
8007 never_direct is the opposite of always_direct. Please read
8008 the description for always_direct if you have not already.
8010 With 'never_direct' you can use ACL elements to specify
8011 requests which should NEVER be forwarded directly to origin
8012 servers. For example, to force the use of a proxy for all
8013 requests, except those in your local domain use something like:
8015 acl local-servers dstdomain .foo.net
8016 never_direct deny local-servers
8017 never_direct allow all
8019 or if Squid is inside a firewall and there are local intranet
8020 servers inside the firewall use something like:
8022 acl local-intranet dstdomain .foo.net
8023 acl local-external dstdomain external.foo.net
8024 always_direct deny local-external
8025 always_direct allow local-intranet
8026 never_direct allow all
8028 This clause supports both fast and slow acl types.
8029 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
8033 ADVANCED NETWORKING OPTIONS
8034 -----------------------------------------------------------------------------
8037 NAME: incoming_udp_average incoming_icp_average
8040 LOC: Config.comm_incoming.udp.average
8042 Heavy voodoo here. I can't even believe you are reading this.
8043 Are you crazy? Don't even think about adjusting these unless
8044 you understand the algorithms in comm_select.c first!
8047 NAME: incoming_tcp_average incoming_http_average
8050 LOC: Config.comm_incoming.tcp.average
8052 Heavy voodoo here. I can't even believe you are reading this.
8053 Are you crazy? Don't even think about adjusting these unless
8054 you understand the algorithms in comm_select.c first!
8057 NAME: incoming_dns_average
8060 LOC: Config.comm_incoming.dns.average
8062 Heavy voodoo here. I can't even believe you are reading this.
8063 Are you crazy? Don't even think about adjusting these unless
8064 you understand the algorithms in comm_select.c first!
8067 NAME: min_udp_poll_cnt min_icp_poll_cnt
8070 LOC: Config.comm_incoming.udp.min_poll
8072 Heavy voodoo here. I can't even believe you are reading this.
8073 Are you crazy? Don't even think about adjusting these unless
8074 you understand the algorithms in comm_select.c first!
8077 NAME: min_dns_poll_cnt
8080 LOC: Config.comm_incoming.dns.min_poll
8082 Heavy voodoo here. I can't even believe you are reading this.
8083 Are you crazy? Don't even think about adjusting these unless
8084 you understand the algorithms in comm_select.c first!
8087 NAME: min_tcp_poll_cnt min_http_poll_cnt
8090 LOC: Config.comm_incoming.tcp.min_poll
8092 Heavy voodoo here. I can't even believe you are reading this.
8093 Are you crazy? Don't even think about adjusting these unless
8094 you understand the algorithms in comm_select.c first!
8100 LOC: Config.accept_filter
8104 The name of an accept(2) filter to install on Squid's
8105 listen socket(s). This feature is perhaps specific to
8106 FreeBSD and requires support in the kernel.
8108 The 'httpready' filter delays delivering new connections
8109 to Squid until a full HTTP request has been received.
8110 See the accf_http(9) man page for details.
8112 The 'dataready' filter delays delivering new connections
8113 to Squid until there is some data to process.
8114 See the accf_dataready(9) man page for details.
8118 The 'data' filter delays delivering of new connections
8119 to Squid until there is some data to process by TCP_ACCEPT_DEFER.
8120 You may optionally specify a number of seconds to wait by
8121 'data=N' where N is the number of seconds. Defaults to 30
8122 if not specified. See the tcp(7) man page for details.
8125 accept_filter httpready
8130 NAME: client_ip_max_connections
8132 LOC: Config.client_ip_max_connections
8134 DEFAULT_DOC: No limit.
8136 Set an absolute limit on the number of connections a single
8137 client IP can use. Any more than this and Squid will begin to drop
8138 new connections from the client until it closes some links.
8140 Note that this is a global limit. It affects all HTTP, HTCP, Gopher and FTP
8141 connections from the client. For finer control use the ACL access controls.
8143 Requires client_db to be enabled (the default).
8145 WARNING: This may noticably slow down traffic received via external proxies
8146 or NAT devices and cause them to rebound error messages back to their clients.
8149 NAME: tcp_recv_bufsize
8153 DEFAULT_DOC: Use operating system TCP defaults.
8154 LOC: Config.tcpRcvBufsz
8156 Size of receive buffer to set for TCP sockets. Probably just
8157 as easy to change your kernel's default.
8158 Omit from squid.conf to use the default buffer size.
8163 -----------------------------------------------------------------------------
8170 LOC: Adaptation::Icap::TheConfig.onoff
8173 If you want to enable the ICAP module support, set this to on.
8176 NAME: icap_connect_timeout
8179 LOC: Adaptation::Icap::TheConfig.connect_timeout_raw
8182 This parameter specifies how long to wait for the TCP connect to
8183 the requested ICAP server to complete before giving up and either
8184 terminating the HTTP transaction or bypassing the failure.
8186 The default for optional services is peer_connect_timeout.
8187 The default for essential services is connect_timeout.
8188 If this option is explicitly set, its value applies to all services.
8191 NAME: icap_io_timeout
8195 DEFAULT_DOC: Use read_timeout.
8196 LOC: Adaptation::Icap::TheConfig.io_timeout_raw
8199 This parameter specifies how long to wait for an I/O activity on
8200 an established, active ICAP connection before giving up and
8201 either terminating the HTTP transaction or bypassing the
8205 NAME: icap_service_failure_limit
8206 COMMENT: limit [in memory-depth time-units]
8207 TYPE: icap_service_failure_limit
8209 LOC: Adaptation::Icap::TheConfig
8212 The limit specifies the number of failures that Squid tolerates
8213 when establishing a new TCP connection with an ICAP service. If
8214 the number of failures exceeds the limit, the ICAP service is
8215 not used for new ICAP requests until it is time to refresh its
8218 A negative value disables the limit. Without the limit, an ICAP
8219 service will not be considered down due to connectivity failures
8220 between ICAP OPTIONS requests.
8222 Squid forgets ICAP service failures older than the specified
8223 value of memory-depth. The memory fading algorithm
8224 is approximate because Squid does not remember individual
8225 errors but groups them instead, splitting the option
8226 value into ten time slots of equal length.
8228 When memory-depth is 0 and by default this option has no
8229 effect on service failure expiration.
8231 Squid always forgets failures when updating service settings
8232 using an ICAP OPTIONS transaction, regardless of this option
8236 # suspend service usage after 10 failures in 5 seconds:
8237 icap_service_failure_limit 10 in 5 seconds
8240 NAME: icap_service_revival_delay
8243 LOC: Adaptation::Icap::TheConfig.service_revival_delay
8246 The delay specifies the number of seconds to wait after an ICAP
8247 OPTIONS request failure before requesting the options again. The
8248 failed ICAP service is considered "down" until fresh OPTIONS are
8251 The actual delay cannot be smaller than the hardcoded minimum
8252 delay of 30 seconds.
8255 NAME: icap_preview_enable
8259 LOC: Adaptation::Icap::TheConfig.preview_enable
8262 The ICAP Preview feature allows the ICAP server to handle the
8263 HTTP message by looking only at the beginning of the message body
8264 or even without receiving the body at all. In some environments,
8265 previews greatly speedup ICAP processing.
8267 During an ICAP OPTIONS transaction, the server may tell Squid what
8268 HTTP messages should be previewed and how big the preview should be.
8269 Squid will not use Preview if the server did not request one.
8271 To disable ICAP Preview for all ICAP services, regardless of
8272 individual ICAP server OPTIONS responses, set this option to "off".
8274 icap_preview_enable off
8277 NAME: icap_preview_size
8280 LOC: Adaptation::Icap::TheConfig.preview_size
8282 DEFAULT_DOC: No preview sent.
8284 The default size of preview data to be sent to the ICAP server.
8285 This value might be overwritten on a per server basis by OPTIONS requests.
8288 NAME: icap_206_enable
8292 LOC: Adaptation::Icap::TheConfig.allow206_enable
8295 206 (Partial Content) responses is an ICAP extension that allows the
8296 ICAP agents to optionally combine adapted and original HTTP message
8297 content. The decision to combine is postponed until the end of the
8298 ICAP response. Squid supports Partial Content extension by default.
8300 Activation of the Partial Content extension is negotiated with each
8301 ICAP service during OPTIONS exchange. Most ICAP servers should handle
8302 negotation correctly even if they do not support the extension, but
8303 some might fail. To disable Partial Content support for all ICAP
8304 services and to avoid any negotiation, set this option to "off".
8310 NAME: icap_default_options_ttl
8313 LOC: Adaptation::Icap::TheConfig.default_options_ttl
8316 The default TTL value for ICAP OPTIONS responses that don't have
8317 an Options-TTL header.
8320 NAME: icap_persistent_connections
8324 LOC: Adaptation::Icap::TheConfig.reuse_connections
8327 Whether or not Squid should use persistent connections to
8331 NAME: adaptation_send_client_ip icap_send_client_ip
8333 IFDEF: USE_ADAPTATION
8335 LOC: Adaptation::Config::send_client_ip
8338 If enabled, Squid shares HTTP client IP information with adaptation
8339 services. For ICAP, Squid adds the X-Client-IP header to ICAP requests.
8340 For eCAP, Squid sets the libecap::metaClientIp transaction option.
8342 See also: adaptation_uses_indirect_client
8345 NAME: adaptation_send_username icap_send_client_username
8347 IFDEF: USE_ADAPTATION
8349 LOC: Adaptation::Config::send_username
8352 This sends authenticated HTTP client username (if available) to
8353 the adaptation service.
8355 For ICAP, the username value is encoded based on the
8356 icap_client_username_encode option and is sent using the header
8357 specified by the icap_client_username_header option.
8360 NAME: icap_client_username_header
8363 LOC: Adaptation::Icap::TheConfig.client_username_header
8364 DEFAULT: X-Client-Username
8366 ICAP request header name to use for adaptation_send_username.
8369 NAME: icap_client_username_encode
8373 LOC: Adaptation::Icap::TheConfig.client_username_encode
8376 Whether to base64 encode the authenticated client username.
8380 TYPE: icap_service_type
8382 LOC: Adaptation::Icap::TheConfig
8385 Defines a single ICAP service using the following format:
8387 icap_service id vectoring_point uri [option ...]
8390 an opaque identifier or name which is used to direct traffic to
8391 this specific service. Must be unique among all adaptation
8392 services in squid.conf.
8394 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
8395 This specifies at which point of transaction processing the
8396 ICAP service should be activated. *_postcache vectoring points
8397 are not yet supported.
8399 uri: icap://servername:port/servicepath
8400 ICAP server and service location.
8401 icaps://servername:port/servicepath
8402 The "icap:" URI scheme is used for traditional ICAP server and
8403 service location (default port is 1344, connections are not
8404 encrypted). The "icaps:" URI scheme is for Secure ICAP
8405 services that use SSL/TLS-encrypted ICAP connections (by
8406 default, on port 11344).
8408 ICAP does not allow a single service to handle both REQMOD and RESPMOD
8409 transactions. Squid does not enforce that requirement. You can specify
8410 services with the same service_url and different vectoring_points. You
8411 can even specify multiple identical services as long as their
8412 service_names differ.
8414 To activate a service, use the adaptation_access directive. To group
8415 services, use adaptation_service_chain and adaptation_service_set.
8417 Service options are separated by white space. ICAP services support
8418 the following name=value options:
8421 If set to 'on' or '1', the ICAP service is treated as
8422 optional. If the service cannot be reached or malfunctions,
8423 Squid will try to ignore any errors and process the message as
8424 if the service was not enabled. No all ICAP errors can be
8425 bypassed. If set to 0, the ICAP service is treated as
8426 essential and all ICAP errors will result in an error page
8427 returned to the HTTP client.
8429 Bypass is off by default: services are treated as essential.
8432 If set to 'on' or '1', the ICAP service is allowed to
8433 dynamically change the current message adaptation plan by
8434 returning a chain of services to be used next. The services
8435 are specified using the X-Next-Services ICAP response header
8436 value, formatted as a comma-separated list of service names.
8437 Each named service should be configured in squid.conf. Other
8438 services are ignored. An empty X-Next-Services value results
8439 in an empty plan which ends the current adaptation.
8441 Dynamic adaptation plan may cross or cover multiple supported
8442 vectoring points in their natural processing order.
8444 Routing is not allowed by default: the ICAP X-Next-Services
8445 response header is ignored.
8448 Only has effect on split-stack systems. The default on those systems
8449 is to use IPv4-only connections. When set to 'on' this option will
8450 make Squid use IPv6-only connections to contact this ICAP service.
8452 on-overload=block|bypass|wait|force
8453 If the service Max-Connections limit has been reached, do
8454 one of the following for each new ICAP transaction:
8455 * block: send an HTTP error response to the client
8456 * bypass: ignore the "over-connected" ICAP service
8457 * wait: wait (in a FIFO queue) for an ICAP connection slot
8458 * force: proceed, ignoring the Max-Connections limit
8460 In SMP mode with N workers, each worker assumes the service
8461 connection limit is Max-Connections/N, even though not all
8462 workers may use a given service.
8464 The default value is "bypass" if service is bypassable,
8465 otherwise it is set to "wait".
8469 Use the given number as the Max-Connections limit, regardless
8470 of the Max-Connections value given by the service, if any.
8472 ==== SSL / ICAPS / TLS OPTIONS ====
8474 These options are used for Secure ICAP (icaps://....) services only.
8476 sslcert=/path/to/ssl/certificate
8477 A client SSL certificate to use when connecting to
8480 sslkey=/path/to/ssl/key
8481 The private SSL key corresponding to sslcert above.
8482 If 'sslkey' is not specified 'sslcert' is assumed to
8483 reference a combined file containing both the
8484 certificate and the key.
8486 sslcipher=... The list of valid SSL ciphers to use when connecting
8487 to this icap server.
8490 The minimum TLS protocol version to permit. To control
8491 SSLv3 use the ssloptions= parameter.
8492 Supported Values: 1.0 (default), 1.1, 1.2
8494 ssloptions=... Specify various SSL implementation options:
8496 NO_SSLv3 Disallow the use of SSLv3
8497 NO_TLSv1 Disallow the use of TLSv1.0
8498 NO_TLSv1_1 Disallow the use of TLSv1.1
8499 NO_TLSv1_2 Disallow the use of TLSv1.2
8501 Always create a new key when using
8502 temporary/ephemeral DH key exchanges
8503 ALL Enable various bug workarounds
8504 suggested as "harmless" by OpenSSL
8505 Be warned that this reduces SSL/TLS
8506 strength to some attacks.
8508 See the OpenSSL SSL_CTX_set_options documentation for a
8511 sslcafile=... A file containing additional CA certificates to use
8512 when verifying the icap server certificate.
8514 sslcapath=... A directory containing additional CA certificates to
8515 use when verifying the icap server certificate.
8517 sslcrlfile=... A certificate revocation list file to use when
8518 verifying the icap server certificate.
8520 sslflags=... Specify various flags modifying the SSL implementation:
8523 Accept certificates even if they fail to
8526 Don't use the default CA list built in
8529 Don't verify the icap server certificate
8530 matches the server name
8532 ssldomain= The icap server name as advertised in it's certificate.
8533 Used for verifying the correctness of the received icap
8534 server certificate. If not specified the icap server
8535 hostname extracted from ICAP URI will be used.
8537 Older icap_service format without optional named parameters is
8538 deprecated but supported for backward compatibility.
8541 icap_service svcBlocker reqmod_precache icap://icap1.mydomain.net:1344/reqmod bypass=0
8542 icap_service svcLogger reqmod_precache icaps://icap2.mydomain.net:11344/reqmod routing=on
8546 TYPE: icap_class_type
8551 This deprecated option was documented to define an ICAP service
8552 chain, even though it actually defined a set of similar, redundant
8553 services, and the chains were not supported.
8555 To define a set of redundant services, please use the
8556 adaptation_service_set directive. For service chains, use
8557 adaptation_service_chain.
8561 TYPE: icap_access_type
8566 This option is deprecated. Please use adaptation_access, which
8567 has the same ICAP functionality, but comes with better
8568 documentation, and eCAP support.
8573 -----------------------------------------------------------------------------
8580 LOC: Adaptation::Ecap::TheConfig.onoff
8583 Controls whether eCAP support is enabled.
8587 TYPE: ecap_service_type
8589 LOC: Adaptation::Ecap::TheConfig
8592 Defines a single eCAP service
8594 ecap_service id vectoring_point uri [option ...]
8597 an opaque identifier or name which is used to direct traffic to
8598 this specific service. Must be unique among all adaptation
8599 services in squid.conf.
8601 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
8602 This specifies at which point of transaction processing the
8603 eCAP service should be activated. *_postcache vectoring points
8604 are not yet supported.
8606 uri: ecap://vendor/service_name?custom&cgi=style¶meters=optional
8607 Squid uses the eCAP service URI to match this configuration
8608 line with one of the dynamically loaded services. Each loaded
8609 eCAP service must have a unique URI. Obtain the right URI from
8610 the service provider.
8612 To activate a service, use the adaptation_access directive. To group
8613 services, use adaptation_service_chain and adaptation_service_set.
8615 Service options are separated by white space. eCAP services support
8616 the following name=value options:
8619 If set to 'on' or '1', the eCAP service is treated as optional.
8620 If the service cannot be reached or malfunctions, Squid will try
8621 to ignore any errors and process the message as if the service
8622 was not enabled. No all eCAP errors can be bypassed.
8623 If set to 'off' or '0', the eCAP service is treated as essential
8624 and all eCAP errors will result in an error page returned to the
8627 Bypass is off by default: services are treated as essential.
8630 If set to 'on' or '1', the eCAP service is allowed to
8631 dynamically change the current message adaptation plan by
8632 returning a chain of services to be used next.
8634 Dynamic adaptation plan may cross or cover multiple supported
8635 vectoring points in their natural processing order.
8637 Routing is not allowed by default.
8639 Older ecap_service format without optional named parameters is
8640 deprecated but supported for backward compatibility.
8644 ecap_service s1 reqmod_precache ecap://filters.R.us/leakDetector?on_error=block bypass=off
8645 ecap_service s2 respmod_precache ecap://filters.R.us/virusFilter config=/etc/vf.cfg bypass=on
8648 NAME: loadable_modules
8650 IFDEF: USE_LOADABLE_MODULES
8651 LOC: Config.loadable_module_names
8654 Instructs Squid to load the specified dynamic module(s) or activate
8655 preloaded module(s).
8657 loadable_modules @DEFAULT_PREFIX@/lib/MinimalAdapter.so
8661 MESSAGE ADAPTATION OPTIONS
8662 -----------------------------------------------------------------------------
8665 NAME: adaptation_service_set
8666 TYPE: adaptation_service_set_type
8667 IFDEF: USE_ADAPTATION
8672 Configures an ordered set of similar, redundant services. This is
8673 useful when hot standby or backup adaptation servers are available.
8675 adaptation_service_set set_name service_name1 service_name2 ...
8677 The named services are used in the set declaration order. The first
8678 applicable adaptation service from the set is used first. The next
8679 applicable service is tried if and only if the transaction with the
8680 previous service fails and the message waiting to be adapted is still
8683 When adaptation starts, broken services are ignored as if they were
8684 not a part of the set. A broken service is a down optional service.
8686 The services in a set must be attached to the same vectoring point
8687 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
8689 If all services in a set are optional then adaptation failures are
8690 bypassable. If all services in the set are essential, then a
8691 transaction failure with one service may still be retried using
8692 another service from the set, but when all services fail, the master
8693 transaction fails as well.
8695 A set may contain a mix of optional and essential services, but that
8696 is likely to lead to surprising results because broken services become
8697 ignored (see above), making previously bypassable failures fatal.
8698 Technically, it is the bypassability of the last failed service that
8701 See also: adaptation_access adaptation_service_chain
8704 adaptation_service_set svcBlocker urlFilterPrimary urlFilterBackup
8705 adaptation service_set svcLogger loggerLocal loggerRemote
8708 NAME: adaptation_service_chain
8709 TYPE: adaptation_service_chain_type
8710 IFDEF: USE_ADAPTATION
8715 Configures a list of complementary services that will be applied
8716 one-by-one, forming an adaptation chain or pipeline. This is useful
8717 when Squid must perform different adaptations on the same message.
8719 adaptation_service_chain chain_name service_name1 svc_name2 ...
8721 The named services are used in the chain declaration order. The first
8722 applicable adaptation service from the chain is used first. The next
8723 applicable service is applied to the successful adaptation results of
8724 the previous service in the chain.
8726 When adaptation starts, broken services are ignored as if they were
8727 not a part of the chain. A broken service is a down optional service.
8729 Request satisfaction terminates the adaptation chain because Squid
8730 does not currently allow declaration of RESPMOD services at the
8731 "reqmod_precache" vectoring point (see icap_service or ecap_service).
8733 The services in a chain must be attached to the same vectoring point
8734 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
8736 A chain may contain a mix of optional and essential services. If an
8737 essential adaptation fails (or the failure cannot be bypassed for
8738 other reasons), the master transaction fails. Otherwise, the failure
8739 is bypassed as if the failed adaptation service was not in the chain.
8741 See also: adaptation_access adaptation_service_set
8744 adaptation_service_chain svcRequest requestLogger urlFilter leakDetector
8747 NAME: adaptation_access
8748 TYPE: adaptation_access_type
8749 IFDEF: USE_ADAPTATION
8752 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
8754 Sends an HTTP transaction to an ICAP or eCAP adaptation service.
8756 adaptation_access service_name allow|deny [!]aclname...
8757 adaptation_access set_name allow|deny [!]aclname...
8759 At each supported vectoring point, the adaptation_access
8760 statements are processed in the order they appear in this
8761 configuration file. Statements pointing to the following services
8762 are ignored (i.e., skipped without checking their ACL):
8764 - services serving different vectoring points
8765 - "broken-but-bypassable" services
8766 - "up" services configured to ignore such transactions
8767 (e.g., based on the ICAP Transfer-Ignore header).
8769 When a set_name is used, all services in the set are checked
8770 using the same rules, to find the first applicable one. See
8771 adaptation_service_set for details.
8773 If an access list is checked and there is a match, the
8774 processing stops: For an "allow" rule, the corresponding
8775 adaptation service is used for the transaction. For a "deny"
8776 rule, no adaptation service is activated.
8778 It is currently not possible to apply more than one adaptation
8779 service at the same vectoring point to the same HTTP transaction.
8781 See also: icap_service and ecap_service
8784 adaptation_access service_1 allow all
8787 NAME: adaptation_service_iteration_limit
8789 IFDEF: USE_ADAPTATION
8790 LOC: Adaptation::Config::service_iteration_limit
8793 Limits the number of iterations allowed when applying adaptation
8794 services to a message. If your longest adaptation set or chain
8795 may have more than 16 services, increase the limit beyond its
8796 default value of 16. If detecting infinite iteration loops sooner
8797 is critical, make the iteration limit match the actual number
8798 of services in your longest adaptation set or chain.
8800 Infinite adaptation loops are most likely with routing services.
8802 See also: icap_service routing=1
8805 NAME: adaptation_masterx_shared_names
8807 IFDEF: USE_ADAPTATION
8808 LOC: Adaptation::Config::masterx_shared_name
8811 For each master transaction (i.e., the HTTP request and response
8812 sequence, including all related ICAP and eCAP exchanges), Squid
8813 maintains a table of metadata. The table entries are (name, value)
8814 pairs shared among eCAP and ICAP exchanges. The table is destroyed
8815 with the master transaction.
8817 This option specifies the table entry names that Squid must accept
8818 from and forward to the adaptation transactions.
8820 An ICAP REQMOD or RESPMOD transaction may set an entry in the
8821 shared table by returning an ICAP header field with a name
8822 specified in adaptation_masterx_shared_names.
8824 An eCAP REQMOD or RESPMOD transaction may set an entry in the
8825 shared table by implementing the libecap::visitEachOption() API
8826 to provide an option with a name specified in
8827 adaptation_masterx_shared_names.
8829 Squid will store and forward the set entry to subsequent adaptation
8830 transactions within the same master transaction scope.
8832 Only one shared entry name is supported at this time.
8835 # share authentication information among ICAP services
8836 adaptation_masterx_shared_names X-Subscriber-ID
8839 NAME: adaptation_meta
8841 IFDEF: USE_ADAPTATION
8842 LOC: Adaptation::Config::metaHeaders
8845 This option allows Squid administrator to add custom ICAP request
8846 headers or eCAP options to Squid ICAP requests or eCAP transactions.
8847 Use it to pass custom authentication tokens and other
8848 transaction-state related meta information to an ICAP/eCAP service.
8850 The addition of a meta header is ACL-driven:
8851 adaptation_meta name value [!]aclname ...
8853 Processing for a given header name stops after the first ACL list match.
8854 Thus, it is impossible to add two headers with the same name. If no ACL
8855 lists match for a given header name, no such header is added. For
8858 # do not debug transactions except for those that need debugging
8859 adaptation_meta X-Debug 1 needs_debugging
8861 # log all transactions except for those that must remain secret
8862 adaptation_meta X-Log 1 !keep_secret
8864 # mark transactions from users in the "G 1" group
8865 adaptation_meta X-Authenticated-Groups "G 1" authed_as_G1
8867 The "value" parameter may be a regular squid.conf token or a "double
8868 quoted string". Within the quoted string, use backslash (\) to escape
8869 any character, which is currently only useful for escaping backslashes
8870 and double quotes. For example,
8871 "this string has one backslash (\\) and two \"quotes\""
8873 Used adaptation_meta header values may be logged via %note
8874 logformat code. If multiple adaptation_meta headers with the same name
8875 are used during master transaction lifetime, the header values are
8876 logged in the order they were used and duplicate values are ignored
8877 (only the first repeated value will be logged).
8883 LOC: Adaptation::Icap::TheConfig.repeat
8884 DEFAULT_IF_NONE: deny all
8886 This ACL determines which retriable ICAP transactions are
8887 retried. Transactions that received a complete ICAP response
8888 and did not have to consume or produce HTTP bodies to receive
8889 that response are usually retriable.
8891 icap_retry allow|deny [!]aclname ...
8893 Squid automatically retries some ICAP I/O timeouts and errors
8894 due to persistent connection race conditions.
8896 See also: icap_retry_limit
8899 NAME: icap_retry_limit
8902 LOC: Adaptation::Icap::TheConfig.repeat_limit
8904 DEFAULT_DOC: No retries are allowed.
8906 Limits the number of retries allowed.
8908 Communication errors due to persistent connection race
8909 conditions are unavoidable, automatically retried, and do not
8910 count against this limit.
8912 See also: icap_retry
8918 -----------------------------------------------------------------------------
8921 NAME: check_hostnames
8924 LOC: Config.onoff.check_hostnames
8926 For security and stability reasons Squid can check
8927 hostnames for Internet standard RFC compliance. If you want
8928 Squid to perform these checks turn this directive on.
8931 NAME: allow_underscore
8934 LOC: Config.onoff.allow_underscore
8936 Underscore characters is not strictly allowed in Internet hostnames
8937 but nevertheless used by many sites. Set this to off if you want
8938 Squid to be strict about the standard.
8939 This check is performed only when check_hostnames is set to on.
8942 NAME: dns_retransmit_interval
8945 LOC: Config.Timeout.idns_retransmit
8947 Initial retransmit interval for DNS queries. The interval is
8948 doubled each time all configured DNS servers have been tried.
8954 LOC: Config.Timeout.idns_query
8956 DNS Query timeout. If no response is received to a DNS query
8957 within this time all DNS servers for the queried domain
8958 are assumed to be unavailable.
8961 NAME: dns_packet_max
8963 DEFAULT_DOC: EDNS disabled
8965 LOC: Config.dns.packet_max
8967 Maximum number of bytes packet size to advertise via EDNS.
8968 Set to "none" to disable EDNS large packet support.
8970 For legacy reasons DNS UDP replies will default to 512 bytes which
8971 is too small for many responses. EDNS provides a means for Squid to
8972 negotiate receiving larger responses back immediately without having
8973 to failover with repeat requests. Responses larger than this limit
8974 will retain the old behaviour of failover to TCP DNS.
8976 Squid has no real fixed limit internally, but allowing packet sizes
8977 over 1500 bytes requires network jumbogram support and is usually not
8980 WARNING: The RFC also indicates that some older resolvers will reply
8981 with failure of the whole request if the extension is added. Some
8982 resolvers have already been identified which will reply with mangled
8983 EDNS response on occasion. Usually in response to many-KB jumbogram
8984 sizes being advertised by Squid.
8985 Squid will currently treat these both as an unable-to-resolve domain
8986 even if it would be resolvable without EDNS.
8993 DEFAULT_DOC: Search for single-label domain names is disabled.
8994 LOC: Config.onoff.res_defnames
8996 Normally the RES_DEFNAMES resolver option is disabled
8997 (see res_init(3)). This prevents caches in a hierarchy
8998 from interpreting single-component hostnames locally. To allow
8999 Squid to handle single-component names, enable this option.
9002 NAME: dns_multicast_local
9006 DEFAULT_DOC: Search for .local and .arpa names is disabled.
9007 LOC: Config.onoff.dns_mdns
9009 When set to on, Squid sends multicast DNS lookups on the local
9010 network for domains ending in .local and .arpa.
9011 This enables local servers and devices to be contacted in an
9012 ad-hoc or zero-configuration network environment.
9015 NAME: dns_nameservers
9018 DEFAULT_DOC: Use operating system definitions
9019 LOC: Config.dns_nameservers
9021 Use this if you want to specify a list of DNS name servers
9022 (IP addresses) to use instead of those given in your
9023 /etc/resolv.conf file.
9025 On Windows platforms, if no value is specified here or in
9026 the /etc/resolv.conf file, the list of DNS name servers are
9027 taken from the Windows registry, both static and dynamic DHCP
9028 configurations are supported.
9030 Example: dns_nameservers 10.0.0.1 192.172.0.4
9035 DEFAULT: @DEFAULT_HOSTS@
9036 LOC: Config.etcHostsPath
9038 Location of the host-local IP name-address associations
9039 database. Most Operating Systems have such a file on different
9041 - Un*X & Linux: /etc/hosts
9042 - Windows NT/2000: %SystemRoot%\system32\drivers\etc\hosts
9043 (%SystemRoot% value install default is c:\winnt)
9044 - Windows XP/2003: %SystemRoot%\system32\drivers\etc\hosts
9045 (%SystemRoot% value install default is c:\windows)
9046 - Windows 9x/Me: %windir%\hosts
9047 (%windir% value is usually c:\windows)
9048 - Cygwin: /etc/hosts
9050 The file contains newline-separated definitions, in the
9051 form ip_address_in_dotted_form name [name ...] names are
9052 whitespace-separated. Lines beginning with an hash (#)
9053 character are comments.
9055 The file is checked at startup and upon configuration.
9056 If set to 'none', it won't be checked.
9057 If append_domain is used, that domain will be added to
9058 domain-local (i.e. not containing any dot character) host
9064 LOC: Config.appendDomain
9066 DEFAULT_DOC: Use operating system definitions
9068 Appends local domain name to hostnames without any dots in
9069 them. append_domain must begin with a period.
9071 Be warned there are now Internet names with no dots in
9072 them using only top-domain names, so setting this may
9073 cause some Internet sites to become unavailable.
9076 append_domain .yourdomain.com
9079 NAME: ignore_unknown_nameservers
9081 LOC: Config.onoff.ignore_unknown_nameservers
9084 By default Squid checks that DNS responses are received
9085 from the same IP addresses they are sent to. If they
9086 don't match, Squid ignores the response and writes a warning
9087 message to cache.log. You can allow responses from unknown
9088 nameservers by setting this option to 'off'.
9094 LOC: Config.dns.v4_first
9096 With the IPv6 Internet being as fast or faster than IPv4 Internet
9097 for most networks Squid prefers to contact websites over IPv6.
9099 This option reverses the order of preference to make Squid contact
9100 dual-stack websites over IPv4 first. Squid will still perform both
9101 IPv6 and IPv4 DNS lookups before connecting.
9104 This option will restrict the situations under which IPv6
9105 connectivity is used (and tested). Hiding network problems
9106 which would otherwise be detected and warned about.
9110 COMMENT: (number of entries)
9113 LOC: Config.ipcache.size
9115 Maximum number of DNS IP cache entries.
9122 LOC: Config.ipcache.low
9129 LOC: Config.ipcache.high
9131 The size, low-, and high-water marks for the IP cache.
9134 NAME: fqdncache_size
9135 COMMENT: (number of entries)
9138 LOC: Config.fqdncache.size
9140 Maximum number of FQDN cache entries.
9145 -----------------------------------------------------------------------------
9148 NAME: configuration_includes_quoted_values
9150 TYPE: configuration_includes_quoted_values
9152 LOC: ConfigParser::RecognizeQuotedValues
9154 If set, Squid will recognize each "quoted string" after a configuration
9155 directive as a single parameter. The quotes are stripped before the
9156 parameter value is interpreted or used.
9157 See "Values with spaces, quotes, and other special characters"
9158 section for more details.
9165 LOC: Config.onoff.mem_pools
9167 If set, Squid will keep pools of allocated (but unused) memory
9168 available for future use. If memory is a premium on your
9169 system and you believe your malloc library outperforms Squid
9170 routines, disable this.
9173 NAME: memory_pools_limit
9177 LOC: Config.MemPools.limit
9179 Used only with memory_pools on:
9180 memory_pools_limit 50 MB
9182 If set to a non-zero value, Squid will keep at most the specified
9183 limit of allocated (but unused) memory in memory pools. All free()
9184 requests that exceed this limit will be handled by your malloc
9185 library. Squid does not pre-allocate any memory, just safe-keeps
9186 objects that otherwise would be free()d. Thus, it is safe to set
9187 memory_pools_limit to a reasonably high value even if your
9188 configuration will use less memory.
9190 If set to none, Squid will keep all memory it can. That is, there
9191 will be no limit on the total amount of memory used for safe-keeping.
9193 To disable memory allocation optimization, do not set
9194 memory_pools_limit to 0 or none. Set memory_pools to "off" instead.
9196 An overhead for maintaining memory pools is not taken into account
9197 when the limit is checked. This overhead is close to four bytes per
9198 object kept. However, pools may actually _save_ memory because of
9199 reduced memory thrashing in your malloc library.
9203 COMMENT: on|off|transparent|truncate|delete
9206 LOC: opt_forwarded_for
9208 If set to "on", Squid will append your client's IP address
9209 in the HTTP requests it forwards. By default it looks like:
9211 X-Forwarded-For: 192.1.2.3
9213 If set to "off", it will appear as
9215 X-Forwarded-For: unknown
9217 If set to "transparent", Squid will not alter the
9218 X-Forwarded-For header in any way.
9220 If set to "delete", Squid will delete the entire
9221 X-Forwarded-For header.
9223 If set to "truncate", Squid will remove all existing
9224 X-Forwarded-For entries, and place the client IP as the sole entry.
9227 NAME: cachemgr_passwd
9228 TYPE: cachemgrpasswd
9230 DEFAULT_DOC: No password. Actions which require password are denied.
9231 LOC: Config.passwd_list
9233 Specify passwords for cachemgr operations.
9235 Usage: cachemgr_passwd password action action ...
9237 Some valid actions are (see cache manager menu for a full list):
9277 * Indicates actions which will not be performed without a
9278 valid password, others can be performed if not listed here.
9280 To disable an action, set the password to "disable".
9281 To allow performing an action without a password, set the
9284 Use the keyword "all" to set the same password for all actions.
9287 cachemgr_passwd secret shutdown
9288 cachemgr_passwd lesssssssecret info stats/objects
9289 cachemgr_passwd disable all
9296 LOC: Config.onoff.client_db
9298 If you want to disable collecting per-client statistics,
9299 turn off client_db here.
9302 NAME: refresh_all_ims
9306 LOC: Config.onoff.refresh_all_ims
9308 When you enable this option, squid will always check
9309 the origin server for an update when a client sends an
9310 If-Modified-Since request. Many browsers use IMS
9311 requests when the user requests a reload, and this
9312 ensures those clients receive the latest version.
9314 By default (off), squid may return a Not Modified response
9315 based on the age of the cached version.
9318 NAME: reload_into_ims
9319 IFDEF: USE_HTTP_VIOLATIONS
9323 LOC: Config.onoff.reload_into_ims
9325 When you enable this option, client no-cache or ``reload''
9326 requests will be changed to If-Modified-Since requests.
9327 Doing this VIOLATES the HTTP standard. Enabling this
9328 feature could make you liable for problems which it
9331 see also refresh_pattern for a more selective approach.
9334 NAME: connect_retries
9336 LOC: Config.connect_retries
9338 DEFAULT_DOC: Do not retry failed connections.
9340 This sets the maximum number of connection attempts made for each
9341 TCP connection. The connect_retries attempts must all still
9342 complete within the connection timeout period.
9344 The default is not to re-try if the first connection attempt fails.
9345 The (not recommended) maximum is 10 tries.
9347 A warning message will be generated if it is set to a too-high
9348 value and the configured value will be over-ridden.
9350 Note: These re-tries are in addition to forward_max_tries
9351 which limit how many different addresses may be tried to find
9355 NAME: retry_on_error
9357 LOC: Config.retry.onerror
9360 If set to ON Squid will automatically retry requests when
9361 receiving an error response with status 403 (Forbidden),
9362 500 (Internal Error), 501 or 503 (Service not available).
9363 Status 502 and 504 (Gateway errors) are always retried.
9365 This is mainly useful if you are in a complex cache hierarchy to
9366 work around access control errors.
9368 NOTE: This retry will attempt to find another working destination.
9369 Which is different from the server which just failed.
9372 NAME: as_whois_server
9374 LOC: Config.as_whois_server
9375 DEFAULT: whois.ra.net
9377 WHOIS server to query for AS numbers. NOTE: AS numbers are
9378 queried only when Squid starts up, not for every request.
9383 LOC: Config.onoff.offline
9386 Enable this option and Squid will never try to validate cached
9390 NAME: uri_whitespace
9391 TYPE: uri_whitespace
9392 LOC: Config.uri_whitespace
9395 What to do with requests that have whitespace characters in the
9398 strip: The whitespace characters are stripped out of the URL.
9399 This is the behavior recommended by RFC2396 and RFC3986
9400 for tolerant handling of generic URI.
9401 NOTE: This is one difference between generic URI and HTTP URLs.
9403 deny: The request is denied. The user receives an "Invalid
9405 This is the behaviour recommended by RFC2616 for safe
9406 handling of HTTP request URL.
9408 allow: The request is allowed and the URI is not changed. The
9409 whitespace characters remain in the URI. Note the
9410 whitespace is passed to redirector processes if they
9412 Note this may be considered a violation of RFC2616
9413 request parsing where whitespace is prohibited in the
9416 encode: The request is allowed and the whitespace characters are
9417 encoded according to RFC1738.
9419 chop: The request is allowed and the URI is chopped at the
9423 NOTE the current Squid implementation of encode and chop violates
9424 RFC2616 by not using a 301 redirect after altering the URL.
9429 LOC: Config.chroot_dir
9432 Specifies a directory where Squid should do a chroot() while
9433 initializing. This also causes Squid to fully drop root
9434 privileges after initializing. This means, for example, if you
9435 use a HTTP port less than 1024 and try to reconfigure, you may
9436 get an error saying that Squid can not open the port.
9439 NAME: balance_on_multiple_ip
9441 LOC: Config.onoff.balance_on_multiple_ip
9444 Modern IP resolvers in squid sort lookup results by preferred access.
9445 By default squid will use these IP in order and only rotates to
9446 the next listed when the most preffered fails.
9448 Some load balancing servers based on round robin DNS have been
9449 found not to preserve user session state across requests
9450 to different IP addresses.
9452 Enabling this directive Squid rotates IP's per request.
9455 NAME: pipeline_prefetch
9456 TYPE: pipelinePrefetch
9457 LOC: Config.pipeline_max_prefetch
9459 DEFAULT_DOC: Do not pre-parse pipelined requests.
9461 HTTP clients may send a pipeline of 1+N requests to Squid using a
9462 single connection, without waiting for Squid to respond to the first
9463 of those requests. This option limits the number of concurrent
9464 requests Squid will try to handle in parallel. If set to N, Squid
9465 will try to receive and process up to 1+N requests on the same
9466 connection concurrently.
9468 Defaults to 0 (off) for bandwidth management and access logging
9471 NOTE: pipelining requires persistent connections to clients.
9473 WARNING: pipelining breaks NTLM and Negotiate/Kerberos authentication.
9476 NAME: high_response_time_warning
9479 LOC: Config.warnings.high_rptm
9481 DEFAULT_DOC: disabled.
9483 If the one-minute median response time exceeds this value,
9484 Squid prints a WARNING with debug level 0 to get the
9485 administrators attention. The value is in milliseconds.
9488 NAME: high_page_fault_warning
9490 LOC: Config.warnings.high_pf
9492 DEFAULT_DOC: disabled.
9494 If the one-minute average page fault rate exceeds this
9495 value, Squid prints a WARNING with debug level 0 to get
9496 the administrators attention. The value is in page faults
9500 NAME: high_memory_warning
9502 LOC: Config.warnings.high_memory
9503 IFDEF: HAVE_MSTATS&&HAVE_GNUMALLOC_H
9505 DEFAULT_DOC: disabled.
9507 If the memory usage (as determined by gnumalloc, if available and used)
9508 exceeds this amount, Squid prints a WARNING with debug level 0 to get
9509 the administrators attention.
9511 # TODO: link high_memory_warning to mempools?
9513 NAME: sleep_after_fork
9514 COMMENT: (microseconds)
9516 LOC: Config.sleep_after_fork
9519 When this is set to a non-zero value, the main Squid process
9520 sleeps the specified number of microseconds after a fork()
9521 system call. This sleep may help the situation where your
9522 system reports fork() failures due to lack of (virtual)
9523 memory. Note, however, if you have a lot of child
9524 processes, these sleep delays will add up and your
9525 Squid will not service requests for some amount of time
9526 until all the child processes have been started.
9527 On Windows value less then 1000 (1 milliseconds) are
9531 NAME: windows_ipaddrchangemonitor
9532 IFDEF: _SQUID_WINDOWS_
9536 LOC: Config.onoff.WIN32_IpAddrChangeMonitor
9538 On Windows Squid by default will monitor IP address changes and will
9539 reconfigure itself after any detected event. This is very useful for
9540 proxies connected to internet with dial-up interfaces.
9541 In some cases (a Proxy server acting as VPN gateway is one) it could be
9542 desiderable to disable this behaviour setting this to 'off'.
9543 Note: after changing this, Squid service must be restarted.
9548 IFDEF: USE_SQUID_EUI
9550 LOC: Eui::TheConfig.euiLookup
9552 Whether to lookup the EUI or MAC address of a connected client.
9555 NAME: max_filedescriptors max_filedesc
9558 DEFAULT_DOC: Use operating system limits set by ulimit.
9559 LOC: Config.max_filedescriptors
9561 Reduce the maximum number of filedescriptors supported below
9562 the usual operating system defaults.
9564 Remove from squid.conf to inherit the current ulimit setting.
9566 Note: Changing this requires a restart of Squid. Also
9567 not all I/O types supports large values (eg on Windows).
9570 NAME: force_request_body_continuation
9572 LOC: Config.accessList.forceRequestBodyContinuation
9574 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
9576 This option controls how Squid handles data upload requests from HTTP
9577 and FTP agents that require a "Please Continue" control message response
9578 to actually send the request body to Squid. It is mostly useful in
9579 adaptation environments.
9581 When Squid receives an HTTP request with an "Expect: 100-continue"
9582 header or an FTP upload command (e.g., STOR), Squid normally sends the
9583 request headers or FTP command information to an adaptation service (or
9584 peer) and waits for a response. Most adaptation services (and some
9585 broken peers) may not respond to Squid at that stage because they may
9586 decide to wait for the HTTP request body or FTP data transfer. However,
9587 that request body or data transfer may never come because Squid has not
9588 responded with the HTTP 100 or FTP 150 (Please Continue) control message
9589 to the request sender yet!
9591 An allow match tells Squid to respond with the HTTP 100 or FTP 150
9592 (Please Continue) control message on its own, before forwarding the
9593 request to an adaptation service or peer. Such a response usually forces
9594 the request sender to proceed with sending the body. A deny match tells
9595 Squid to delay that control response until the origin server confirms
9596 that the request body is needed. Delaying is the default behavior.
projects / thirdparty / squid.git / blob