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 %un A user name. Expands to the first available name
768 from the following list of information sources:
769 - authenticated user name, like %ul or %LOGIN
770 - user name sent by an external ACL, like %EXT_USER
771 - SSL client name, like %us in logformat
772 - ident user name, like %ui in logformat
773 %EXT_USER Username from previous external acl
774 %EXT_LOG Log details from previous external acl
775 %EXT_TAG Tag from previous external acl
776 %IDENT Ident user name
778 %SRCPORT Client source port
781 %PROTO Requested URL scheme
783 %PATH Requested URL path
784 %METHOD Request method
785 %MYADDR Squid interface address
786 %MYPORT Squid http_port number
787 %PATH Requested URL-path (including query-string if any)
788 %USER_CERT SSL User certificate in PEM format
789 %USER_CERTCHAIN SSL User certificate chain in PEM format
790 %USER_CERT_xx SSL User certificate subject attribute xx
791 %USER_CA_CERT_xx SSL User certificate issuer attribute xx
792 %ssl::>sni SSL client SNI sent to Squid
793 %ssl::<cert_subject SSL server certificate DN
794 %ssl::<cert_issuer SSL server certificate issuer DN
796 %>{Header} HTTP request header "Header"
798 HTTP request header "Hdr" list member "member"
800 HTTP request header list member using ; as
801 list separator. ; can be any non-alphanumeric
804 %<{Header} HTTP reply header "Header"
806 HTTP reply header "Hdr" list member "member"
808 HTTP reply header list member using ; as
809 list separator. ; can be any non-alphanumeric
812 %ACL The name of the ACL being tested.
813 %DATA The ACL arguments. If not used then any arguments
814 is automatically added at the end of the line
816 NOTE: this will encode the arguments as one token,
817 whereas the default will pass each separately.
819 %% The percent sign. Useful for helpers which need
820 an unchanging input format.
823 General request syntax:
825 [channel-ID] FORMAT-values [acl-values ...]
828 FORMAT-values consists of transaction details expanded with
829 whitespace separation per the config file FORMAT specification
830 using the FORMAT macros listed above.
832 acl-values consists of any string specified in the referencing
833 config 'acl ... external' line. see the "acl external" directive.
835 Request values sent to the helper are URL escaped to protect
836 each value in requests against whitespaces.
838 If using protocol=2.5 then the request sent to the helper is not
839 URL escaped to protect against whitespace.
841 NOTE: protocol=3.0 is deprecated as no longer necessary.
843 When using the concurrency= option the protocol is changed by
844 introducing a query channel tag in front of the request/response.
845 The query channel tag is a number between 0 and concurrency-1.
846 This value must be echoed back unchanged to Squid as the first part
847 of the response relating to its request.
850 The helper receives lines expanded per the above format specification
851 and for each input line returns 1 line starting with OK/ERR/BH result
852 code and optionally followed by additional keywords with more details.
855 General result syntax:
857 [channel-ID] result keyword=value ...
859 Result consists of one of the codes:
862 the ACL test produced a match.
865 the ACL test does not produce a match.
868 An internal error occurred in the helper, preventing
869 a result being identified.
871 The meaning of 'a match' is determined by your squid.conf
872 access control configuration. See the Squid wiki for details.
876 user= The users name (login)
878 password= The users password (for login= cache_peer option)
880 message= Message describing the reason for this response.
881 Available as %o in error pages.
882 Useful on (ERR and BH results).
884 tag= Apply a tag to a request. Only sets a tag once,
885 does not alter existing tags.
887 log= String to be logged in access.log. Available as
888 %ea in logformat specifications.
890 clt_conn_tag= Associates a TAG with the client TCP connection.
891 Please see url_rewrite_program related documentation
894 Any keywords may be sent on any response whether OK, ERR or BH.
896 All response keyword values need to be a single token with URL
897 escaping, or enclosed in double quotes (") and escaped using \ on
898 any double quotes or \ characters within the value. The wrapping
899 double quotes are removed before the value is interpreted by Squid.
900 \r and \n are also replace by CR and LF.
902 Some example key values:
906 user="J. \"Bob\" Smith"
913 DEFAULT: ssl::certHasExpired ssl_error X509_V_ERR_CERT_HAS_EXPIRED
914 DEFAULT: ssl::certNotYetValid ssl_error X509_V_ERR_CERT_NOT_YET_VALID
915 DEFAULT: ssl::certDomainMismatch ssl_error SQUID_X509_V_ERR_DOMAIN_MISMATCH
916 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
917 DEFAULT: ssl::certSelfSigned ssl_error X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT
920 DEFAULT: manager url_regex -i ^cache_object:// +i ^https?://[^/]+/squid-internal-mgr/
921 DEFAULT: localhost src 127.0.0.1/32 ::1
922 DEFAULT: to_localhost dst 127.0.0.0/8 0.0.0.0/32 ::1
923 DEFAULT_DOC: ACLs all, manager, localhost, and to_localhost are predefined.
925 Defining an Access List
927 Every access list definition must begin with an aclname and acltype,
928 followed by either type-specific arguments or a quoted filename that
931 acl aclname acltype argument ...
932 acl aclname acltype "file" ...
934 When using "file", the file should contain one item per line.
936 Some acl types supports options which changes their default behaviour.
937 The available options are:
939 -i,+i By default, regular expressions are CASE-SENSITIVE. To make them
940 case-insensitive, use the -i option. To return case-sensitive
941 use the +i option between patterns, or make a new ACL line
944 -n Disable lookups and address type conversions. If lookup or
945 conversion is required because the parameter type (IP or
946 domain name) does not match the message address type (domain
947 name or IP), then the ACL would immediately declare a mismatch
948 without any warnings or lookups.
950 -- Used to stop processing all options, in the case the first acl
951 value has '-' character as first character (for example the '-'
952 is a valid domain name)
954 Some acl types require suspending the current request in order
955 to access some external data source.
956 Those which do are marked with the tag [slow], those which
957 don't are marked as [fast].
958 See http://wiki.squid-cache.org/SquidFaq/SquidAcl
959 for further information
961 ***** ACL TYPES AVAILABLE *****
963 acl aclname src ip-address/mask ... # clients IP address [fast]
964 acl aclname src addr1-addr2/mask ... # range of addresses [fast]
965 acl aclname dst [-n] ip-address/mask ... # URL host's IP address [slow]
966 acl aclname localip ip-address/mask ... # IP address the client connected to [fast]
968 acl aclname arp mac-address ... (xx:xx:xx:xx:xx:xx notation)
969 # The arp ACL requires the special configure option --enable-arp-acl.
970 # Furthermore, the ARP ACL code is not portable to all operating systems.
971 # It works on Linux, Solaris, Windows, FreeBSD, and some
972 # other *BSD variants.
975 # NOTE: Squid can only determine the MAC address for clients that are on
976 # the same subnet. If the client is on a different subnet,
977 # then Squid cannot find out its MAC address.
979 acl aclname srcdomain .foo.com ...
980 # reverse lookup, from client IP [slow]
981 acl aclname dstdomain [-n] .foo.com ...
982 # Destination server from URL [fast]
983 acl aclname srcdom_regex [-i] \.foo\.com ...
984 # regex matching client name [slow]
985 acl aclname dstdom_regex [-n] [-i] \.foo\.com ...
986 # regex matching server [fast]
988 # For dstdomain and dstdom_regex a reverse lookup is tried if a IP
989 # based URL is used and no match is found. The name "none" is used
990 # if the reverse lookup fails.
992 acl aclname src_as number ...
993 acl aclname dst_as number ...
995 # Except for access control, AS numbers can be used for
996 # routing of requests to specific caches. Here's an
997 # example for routing all requests for AS#1241 and only
998 # those to mycache.mydomain.net:
999 # acl asexample dst_as 1241
1000 # cache_peer_access mycache.mydomain.net allow asexample
1001 # cache_peer_access mycache_mydomain.net deny all
1003 acl aclname peername myPeer ...
1005 # match against a named cache_peer entry
1006 # set unique name= on cache_peer lines for reliable use.
1008 acl aclname time [day-abbrevs] [h1:m1-h2:m2]
1018 # h1:m1 must be less than h2:m2
1020 acl aclname url_regex [-i] ^http:// ...
1021 # regex matching on whole URL [fast]
1022 acl aclname urllogin [-i] [^a-zA-Z0-9] ...
1023 # regex matching on URL login field
1024 acl aclname urlpath_regex [-i] \.gif$ ...
1025 # regex matching on URL path [fast]
1027 acl aclname port 80 70 21 0-1024... # destination TCP port [fast]
1029 acl aclname localport 3128 ... # TCP port the client connected to [fast]
1030 # NP: for interception mode this is usually '80'
1032 acl aclname myportname 3128 ... # *_port name [fast]
1034 acl aclname proto HTTP FTP ... # request protocol [fast]
1036 acl aclname method GET POST ... # HTTP request method [fast]
1038 acl aclname http_status 200 301 500- 400-403 ...
1039 # status code in reply [fast]
1041 acl aclname browser [-i] regexp ...
1042 # pattern match on User-Agent header (see also req_header below) [fast]
1044 acl aclname referer_regex [-i] regexp ...
1045 # pattern match on Referer header [fast]
1046 # Referer is highly unreliable, so use with care
1048 acl aclname ident username ...
1049 acl aclname ident_regex [-i] pattern ...
1050 # string match on ident output [slow]
1051 # use REQUIRED to accept any non-null ident.
1053 acl aclname proxy_auth [-i] username ...
1054 acl aclname proxy_auth_regex [-i] pattern ...
1055 # perform http authentication challenge to the client and match against
1056 # supplied credentials [slow]
1058 # takes a list of allowed usernames.
1059 # use REQUIRED to accept any valid username.
1061 # Will use proxy authentication in forward-proxy scenarios, and plain
1062 # http authenticaiton in reverse-proxy scenarios
1064 # NOTE: when a Proxy-Authentication header is sent but it is not
1065 # needed during ACL checking the username is NOT logged
1068 # NOTE: proxy_auth requires a EXTERNAL authentication program
1069 # to check username/password combinations (see
1070 # auth_param directive).
1072 # NOTE: proxy_auth can't be used in a transparent/intercepting proxy
1073 # as the browser needs to be configured for using a proxy in order
1074 # to respond to proxy authentication.
1076 acl aclname snmp_community string ...
1077 # A community string to limit access to your SNMP Agent [fast]
1080 # acl snmppublic snmp_community public
1082 acl aclname maxconn number
1083 # This will be matched when the client's IP address has
1084 # more than <number> TCP connections established. [fast]
1085 # NOTE: This only measures direct TCP links so X-Forwarded-For
1086 # indirect clients are not counted.
1088 acl aclname max_user_ip [-s] number
1089 # This will be matched when the user attempts to log in from more
1090 # than <number> different ip addresses. The authenticate_ip_ttl
1091 # parameter controls the timeout on the ip entries. [fast]
1092 # If -s is specified the limit is strict, denying browsing
1093 # from any further IP addresses until the ttl has expired. Without
1094 # -s Squid will just annoy the user by "randomly" denying requests.
1095 # (the counter is reset each time the limit is reached and a
1096 # request is denied)
1097 # NOTE: in acceleration mode or where there is mesh of child proxies,
1098 # clients may appear to come from multiple addresses if they are
1099 # going through proxy farms, so a limit of 1 may cause user problems.
1101 acl aclname random probability
1102 # Pseudo-randomly match requests. Based on the probability given.
1103 # Probability may be written as a decimal (0.333), fraction (1/3)
1104 # or ratio of matches:non-matches (3:5).
1106 acl aclname req_mime_type [-i] mime-type ...
1107 # regex match against the mime type of the request generated
1108 # by the client. Can be used to detect file upload or some
1109 # types HTTP tunneling requests [fast]
1110 # NOTE: This does NOT match the reply. You cannot use this
1111 # to match the returned file type.
1113 acl aclname req_header header-name [-i] any\.regex\.here
1114 # regex match against any of the known request headers. May be
1115 # thought of as a superset of "browser", "referer" and "mime-type"
1118 acl aclname rep_mime_type [-i] mime-type ...
1119 # regex match against the mime type of the reply received by
1120 # squid. Can be used to detect file download or some
1121 # types HTTP tunneling requests. [fast]
1122 # NOTE: This has no effect in http_access rules. It only has
1123 # effect in rules that affect the reply data stream such as
1124 # http_reply_access.
1126 acl aclname rep_header header-name [-i] any\.regex\.here
1127 # regex match against any of the known reply headers. May be
1128 # thought of as a superset of "browser", "referer" and "mime-type"
1131 acl aclname external class_name [arguments...]
1132 # external ACL lookup via a helper class defined by the
1133 # external_acl_type directive [slow]
1135 acl aclname user_cert attribute values...
1136 # match against attributes in a user SSL certificate
1137 # attribute is one of DN/C/O/CN/L/ST or a numerical OID [fast]
1139 acl aclname ca_cert attribute values...
1140 # match against attributes a users issuing CA SSL certificate
1141 # attribute is one of DN/C/O/CN/L/ST or a numerical OID [fast]
1143 acl aclname ext_user username ...
1144 acl aclname ext_user_regex [-i] pattern ...
1145 # string match on username returned by external acl helper [slow]
1146 # use REQUIRED to accept any non-null user name.
1148 acl aclname tag tagvalue ...
1149 # string match on tag returned by external acl helper [fast]
1150 # DEPRECATED. Only the first tag will match with this ACL.
1151 # Use the 'note' ACL instead for handling multiple tag values.
1153 acl aclname hier_code codename ...
1154 # string match against squid hierarchy code(s); [fast]
1155 # e.g., DIRECT, PARENT_HIT, NONE, etc.
1157 # NOTE: This has no effect in http_access rules. It only has
1158 # effect in rules that affect the reply data stream such as
1159 # http_reply_access.
1161 acl aclname note name [value ...]
1162 # match transaction annotation [fast]
1163 # Without values, matches any annotation with a given name.
1164 # With value(s), matches any annotation with a given name that
1165 # also has one of the given values.
1166 # Names and values are compared using a string equality test.
1167 # Annotation sources include note and adaptation_meta directives
1168 # as well as helper and eCAP responses.
1170 acl aclname adaptation_service service ...
1171 # Matches the name of any icap_service, ecap_service,
1172 # adaptation_service_set, or adaptation_service_chain that Squid
1173 # has used (or attempted to use) for the master transaction.
1174 # This ACL must be defined after the corresponding adaptation
1175 # service is named in squid.conf. This ACL is usable with
1176 # adaptation_meta because it starts matching immediately after
1177 # the service has been selected for adaptation.
1180 acl aclname ssl_error errorname
1181 # match against SSL certificate validation error [fast]
1183 # For valid error names see in @DEFAULT_ERROR_DIR@/templates/error-details.txt
1186 # The following can be used as shortcuts for certificate properties:
1187 # [ssl::]certHasExpired: the "not after" field is in the past
1188 # [ssl::]certNotYetValid: the "not before" field is in the future
1189 # [ssl::]certUntrusted: The certificate issuer is not to be trusted.
1190 # [ssl::]certSelfSigned: The certificate is self signed.
1191 # [ssl::]certDomainMismatch: The certificate CN domain does not
1192 # match the name the name of the host we are connecting to.
1194 # The ssl::certHasExpired, ssl::certNotYetValid, ssl::certDomainMismatch,
1195 # ssl::certUntrusted, and ssl::certSelfSigned can also be used as
1196 # predefined ACLs, just like the 'all' ACL.
1198 # NOTE: The ssl_error ACL is only supported with sslproxy_cert_error,
1199 # sslproxy_cert_sign, and sslproxy_cert_adapt options.
1201 acl aclname server_cert_fingerprint [-sha1] fingerprint
1202 # match against server SSL certificate fingerprint [fast]
1204 # The fingerprint is the digest of the DER encoded version
1205 # of the whole certificate. The user should use the form: XX:XX:...
1206 # Optional argument specifies the digest algorithm to use.
1207 # The SHA1 digest algorithm is the default and is currently
1208 # the only algorithm supported (-sha1).
1210 acl aclname at_step step
1211 # match against the current step during ssl_bump evaluation [fast]
1212 # Never matches and should not be used outside the ssl_bump context.
1214 # At each SslBump step, Squid evaluates ssl_bump directives to find
1215 # the next bumping action (e.g., peek or splice). Valid SslBump step
1216 # values and the corresponding ssl_bump evaluation moments are:
1217 # SslBump1: After getting TCP-level and HTTP CONNECT info.
1218 # SslBump2: After getting SSL Client Hello info.
1219 # SslBump3: After getting SSL Server Hello info.
1221 acl aclname ssl::server_name .foo.com ...
1222 # matches server name obtained from various sources [fast]
1224 # The server name is obtained during Ssl-Bump steps from such sources
1225 # as CONNECT request URI, client SNI, and SSL server certificate CN.
1226 # During each Ssl-Bump step, Squid may improve its understanding of a
1227 # "true server name". Unlike dstdomain, this ACL does not perform
1230 acl aclname ssl::server_name_regex [-i] \.foo\.com ...
1231 # regex matches server name obtained from various sources [fast]
1233 acl aclname any-of acl1 acl2 ...
1234 # match any one of the acls [fast or slow]
1235 # The first matching ACL stops further ACL evaluation.
1237 # ACLs from multiple any-of lines with the same name are ORed.
1238 # For example, A = (a1 or a2) or (a3 or a4) can be written as
1239 # acl A any-of a1 a2
1240 # acl A any-of a3 a4
1242 # This group ACL is fast if all evaluated ACLs in the group are fast
1243 # and slow otherwise.
1245 acl aclname all-of acl1 acl2 ...
1246 # match all of the acls [fast or slow]
1247 # The first mismatching ACL stops further ACL evaluation.
1249 # ACLs from multiple all-of lines with the same name are ORed.
1250 # For example, B = (b1 and b2) or (b3 and b4) can be written as
1251 # acl B all-of b1 b2
1252 # acl B all-of b3 b4
1254 # This group ACL is fast if all evaluated ACLs in the group are fast
1255 # and slow otherwise.
1258 acl macaddress arp 09:00:2b:23:45:67
1259 acl myexample dst_as 1241
1260 acl password proxy_auth REQUIRED
1261 acl fileupload req_mime_type -i ^multipart/form-data$
1262 acl javascript rep_mime_type -i ^application/x-javascript$
1266 # Recommended minimum configuration:
1269 # Example rule allowing access from your local networks.
1270 # Adapt to list your (internal) IP networks from where browsing
1272 acl localnet src 0.0.0.1-0.255.255.255 # RFC 1122 "this" network (LAN)
1273 acl localnet src 10.0.0.0/8 # RFC 1918 local private network (LAN)
1274 acl localnet src 100.64.0.0/10 # RFC 6598 shared address space (CGN)
1275 acl localhet src 169.254.0.0/16 # RFC 3927 link-local (directly plugged) machines
1276 acl localnet src 172.16.0.0/12 # RFC 1918 local private network (LAN)
1277 acl localnet src 192.168.0.0/16 # RFC 1918 local private network (LAN)
1278 acl localnet src fc00::/7 # RFC 4193 local private network range
1279 acl localnet src fe80::/10 # RFC 4291 link-local (directly plugged) machines
1281 acl SSL_ports port 443
1282 acl Safe_ports port 80 # http
1283 acl Safe_ports port 21 # ftp
1284 acl Safe_ports port 443 # https
1285 acl Safe_ports port 70 # gopher
1286 acl Safe_ports port 210 # wais
1287 acl Safe_ports port 1025-65535 # unregistered ports
1288 acl Safe_ports port 280 # http-mgmt
1289 acl Safe_ports port 488 # gss-http
1290 acl Safe_ports port 591 # filemaker
1291 acl Safe_ports port 777 # multiling http
1292 acl CONNECT method CONNECT
1296 NAME: proxy_protocol_access
1298 LOC: Config.accessList.proxyProtocol
1300 DEFAULT_DOC: all TCP connections to ports with require-proxy-header will be denied
1302 Determine which client proxies can be trusted to provide correct
1303 information regarding real client IP address using PROXY protocol.
1305 Requests may pass through a chain of several other proxies
1306 before reaching us. The original source details may by sent in:
1307 * HTTP message Forwarded header, or
1308 * HTTP message X-Forwarded-For header, or
1309 * PROXY protocol connection header.
1311 This directive is solely for validating new PROXY protocol
1312 connections received from a port flagged with require-proxy-header.
1313 It is checked only once after TCP connection setup.
1315 A deny match results in TCP connection closure.
1317 An allow match is required for Squid to permit the corresponding
1318 TCP connection, before Squid even looks for HTTP request headers.
1319 If there is an allow match, Squid starts using PROXY header information
1320 to determine the source address of the connection for all future ACL
1321 checks, logging, etc.
1323 SECURITY CONSIDERATIONS:
1325 Any host from which we accept client IP details can place
1326 incorrect information in the relevant header, and Squid
1327 will use the incorrect information as if it were the
1328 source address of the request. This may enable remote
1329 hosts to bypass any access control restrictions that are
1330 based on the client's source addresses.
1332 This clause only supports fast acl types.
1333 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1336 NAME: follow_x_forwarded_for
1338 IFDEF: FOLLOW_X_FORWARDED_FOR
1339 LOC: Config.accessList.followXFF
1340 DEFAULT_IF_NONE: deny all
1341 DEFAULT_DOC: X-Forwarded-For header will be ignored.
1343 Determine which client proxies can be trusted to provide correct
1344 information regarding real client IP address.
1346 Requests may pass through a chain of several other proxies
1347 before reaching us. The original source details may by sent in:
1348 * HTTP message Forwarded header, or
1349 * HTTP message X-Forwarded-For header, or
1350 * PROXY protocol connection header.
1352 PROXY protocol connections are controlled by the proxy_protocol_access
1353 directive which is checked before this.
1355 If a request reaches us from a source that is allowed by this
1356 directive, then we trust the information it provides regarding
1357 the IP of the client it received from (if any).
1359 For the purpose of ACLs used in this directive the src ACL type always
1360 matches the address we are testing and srcdomain matches its rDNS.
1362 On each HTTP request Squid checks for X-Forwarded-For header fields.
1363 If found the header values are iterated in reverse order and an allow
1364 match is required for Squid to continue on to the next value.
1365 The verification ends when a value receives a deny match, cannot be
1366 tested, or there are no more values to test.
1367 NOTE: Squid does not yet follow the Forwarded HTTP header.
1369 The end result of this process is an IP address that we will
1370 refer to as the indirect client address. This address may
1371 be treated as the client address for access control, ICAP, delay
1372 pools and logging, depending on the acl_uses_indirect_client,
1373 icap_uses_indirect_client, delay_pool_uses_indirect_client,
1374 log_uses_indirect_client and tproxy_uses_indirect_client options.
1376 This clause only supports fast acl types.
1377 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1379 SECURITY CONSIDERATIONS:
1381 Any host from which we accept client IP details can place
1382 incorrect information in the relevant header, and Squid
1383 will use the incorrect information as if it were the
1384 source address of the request. This may enable remote
1385 hosts to bypass any access control restrictions that are
1386 based on the client's source addresses.
1390 acl localhost src 127.0.0.1
1391 acl my_other_proxy srcdomain .proxy.example.com
1392 follow_x_forwarded_for allow localhost
1393 follow_x_forwarded_for allow my_other_proxy
1396 NAME: acl_uses_indirect_client
1399 IFDEF: FOLLOW_X_FORWARDED_FOR
1401 LOC: Config.onoff.acl_uses_indirect_client
1403 Controls whether the indirect client address
1404 (see follow_x_forwarded_for) is used instead of the
1405 direct client address in acl matching.
1407 NOTE: maxconn ACL considers direct TCP links and indirect
1408 clients will always have zero. So no match.
1411 NAME: delay_pool_uses_indirect_client
1414 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_DELAY_POOLS
1416 LOC: Config.onoff.delay_pool_uses_indirect_client
1418 Controls whether the indirect client address
1419 (see follow_x_forwarded_for) is used instead of the
1420 direct client address in delay pools.
1423 NAME: log_uses_indirect_client
1426 IFDEF: FOLLOW_X_FORWARDED_FOR
1428 LOC: Config.onoff.log_uses_indirect_client
1430 Controls whether the indirect client address
1431 (see follow_x_forwarded_for) is used instead of the
1432 direct client address in the access log.
1435 NAME: tproxy_uses_indirect_client
1438 IFDEF: FOLLOW_X_FORWARDED_FOR&&LINUX_NETFILTER
1440 LOC: Config.onoff.tproxy_uses_indirect_client
1442 Controls whether the indirect client address
1443 (see follow_x_forwarded_for) is used instead of the
1444 direct client address when spoofing the outgoing client.
1446 This has no effect on requests arriving in non-tproxy
1449 SECURITY WARNING: Usage of this option is dangerous
1450 and should not be used trivially. Correct configuration
1451 of follow_x_forwarded_for with a limited set of trusted
1452 sources is required to prevent abuse of your proxy.
1455 NAME: spoof_client_ip
1457 LOC: Config.accessList.spoof_client_ip
1459 DEFAULT_DOC: Allow spoofing on all TPROXY traffic.
1461 Control client IP address spoofing of TPROXY traffic based on
1462 defined access lists.
1464 spoof_client_ip allow|deny [!]aclname ...
1466 If there are no "spoof_client_ip" lines present, the default
1467 is to "allow" spoofing of any suitable request.
1469 Note that the cache_peer "no-tproxy" option overrides this ACL.
1471 This clause supports fast acl types.
1472 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1477 LOC: Config.accessList.http
1478 DEFAULT_IF_NONE: deny all
1479 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1481 Allowing or Denying access based on defined access lists
1483 To allow or deny a message received on an HTTP, HTTPS, or FTP port:
1484 http_access allow|deny [!]aclname ...
1486 NOTE on default values:
1488 If there are no "access" lines present, the default is to deny
1491 If none of the "access" lines cause a match, the default is the
1492 opposite of the last line in the list. If the last line was
1493 deny, the default is allow. Conversely, if the last line
1494 is allow, the default will be deny. For these reasons, it is a
1495 good idea to have an "deny all" entry at the end of your access
1496 lists to avoid potential confusion.
1498 This clause supports both fast and slow acl types.
1499 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1504 # Recommended minimum Access Permission configuration:
1506 # Deny requests to certain unsafe ports
1507 http_access deny !Safe_ports
1509 # Deny CONNECT to other than secure SSL ports
1510 http_access deny CONNECT !SSL_ports
1512 # Only allow cachemgr access from localhost
1513 http_access allow localhost manager
1514 http_access deny manager
1516 # We strongly recommend the following be uncommented to protect innocent
1517 # web applications running on the proxy server who think the only
1518 # one who can access services on "localhost" is a local user
1519 #http_access deny to_localhost
1522 # INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS
1525 # Example rule allowing access from your local networks.
1526 # Adapt localnet in the ACL section to list your (internal) IP networks
1527 # from where browsing should be allowed
1528 http_access allow localnet
1529 http_access allow localhost
1531 # And finally deny all other access to this proxy
1532 http_access deny all
1536 NAME: adapted_http_access http_access2
1538 LOC: Config.accessList.adapted_http
1540 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1542 Allowing or Denying access based on defined access lists
1544 Essentially identical to http_access, but runs after redirectors
1545 and ICAP/eCAP adaptation. Allowing access control based on their
1548 If not set then only http_access is used.
1551 NAME: http_reply_access
1553 LOC: Config.accessList.reply
1555 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1557 Allow replies to client requests. This is complementary to http_access.
1559 http_reply_access allow|deny [!] aclname ...
1561 NOTE: if there are no access lines present, the default is to allow
1564 If none of the access lines cause a match the opposite of the
1565 last line will apply. Thus it is good practice to end the rules
1566 with an "allow all" or "deny all" entry.
1568 This clause supports both fast and slow acl types.
1569 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1574 LOC: Config.accessList.icp
1576 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1578 Allowing or Denying access to the ICP port based on defined
1581 icp_access allow|deny [!]aclname ...
1583 NOTE: The default if no icp_access lines are present is to
1584 deny all traffic. This default may cause problems with peers
1587 This clause only supports fast acl types.
1588 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1590 # Allow ICP queries from local networks only
1591 #icp_access allow localnet
1592 #icp_access deny all
1598 LOC: Config.accessList.htcp
1600 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1602 Allowing or Denying access to the HTCP port based on defined
1605 htcp_access allow|deny [!]aclname ...
1607 See also htcp_clr_access for details on access control for
1608 cache purge (CLR) HTCP messages.
1610 NOTE: The default if no htcp_access lines are present is to
1611 deny all traffic. This default may cause problems with peers
1612 using the htcp option.
1614 This clause only supports fast acl types.
1615 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1617 # Allow HTCP queries from local networks only
1618 #htcp_access allow localnet
1619 #htcp_access deny all
1622 NAME: htcp_clr_access
1625 LOC: Config.accessList.htcp_clr
1627 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1629 Allowing or Denying access to purge content using HTCP based
1630 on defined access lists.
1631 See htcp_access for details on general HTCP access control.
1633 htcp_clr_access allow|deny [!]aclname ...
1635 This clause only supports fast acl types.
1636 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1638 # Allow HTCP CLR requests from trusted peers
1639 acl htcp_clr_peer src 192.0.2.2 2001:DB8::2
1640 htcp_clr_access allow htcp_clr_peer
1641 htcp_clr_access deny all
1646 LOC: Config.accessList.miss
1648 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1650 Determins whether network access is permitted when satisfying a request.
1653 to force your neighbors to use you as a sibling instead of
1656 acl localclients src 192.0.2.0/24 2001:DB8::a:0/64
1657 miss_access deny !localclients
1658 miss_access allow all
1660 This means only your local clients are allowed to fetch relayed/MISS
1661 replies from the network and all other clients can only fetch cached
1664 The default for this setting allows all clients who passed the
1665 http_access rules to relay via this proxy.
1667 This clause only supports fast acl types.
1668 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1671 NAME: ident_lookup_access
1675 DEFAULT_DOC: Unless rules exist in squid.conf, IDENT is not fetched.
1676 LOC: Ident::TheConfig.identLookup
1678 A list of ACL elements which, if matched, cause an ident
1679 (RFC 931) lookup to be performed for this request. For
1680 example, you might choose to always perform ident lookups
1681 for your main multi-user Unix boxes, but not for your Macs
1682 and PCs. By default, ident lookups are not performed for
1685 To enable ident lookups for specific client addresses, you
1686 can follow this example:
1688 acl ident_aware_hosts src 198.168.1.0/24
1689 ident_lookup_access allow ident_aware_hosts
1690 ident_lookup_access deny all
1692 Only src type ACL checks are fully supported. A srcdomain
1693 ACL might work at times, but it will not always provide
1696 This clause only supports fast acl types.
1697 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1700 NAME: reply_body_max_size
1701 COMMENT: size [acl acl...]
1704 DEFAULT_DOC: No limit is applied.
1705 LOC: Config.ReplyBodySize
1707 This option specifies the maximum size of a reply body. It can be
1708 used to prevent users from downloading very large files, such as
1709 MP3's and movies. When the reply headers are received, the
1710 reply_body_max_size lines are processed, and the first line where
1711 all (if any) listed ACLs are true is used as the maximum body size
1714 This size is checked twice. First when we get the reply headers,
1715 we check the content-length value. If the content length value exists
1716 and is larger than the allowed size, the request is denied and the
1717 user receives an error message that says "the request or reply
1718 is too large." If there is no content-length, and the reply
1719 size exceeds this limit, the client's connection is just closed
1720 and they will receive a partial reply.
1722 WARNING: downstream caches probably can not detect a partial reply
1723 if there is no content-length header, so they will cache
1724 partial responses and give them out as hits. You should NOT
1725 use this option if you have downstream caches.
1727 WARNING: A maximum size smaller than the size of squid's error messages
1728 will cause an infinite loop and crash squid. Ensure that the smallest
1729 non-zero value you use is greater that the maximum header size plus
1730 the size of your largest error page.
1732 If you set this parameter none (the default), there will be
1735 Configuration Format is:
1736 reply_body_max_size SIZE UNITS [acl ...]
1738 reply_body_max_size 10 MB
1742 NAME: on_unsupported_protocol
1743 TYPE: on_unsupported_protocol
1744 LOC: Config.accessList.on_unsupported_protocol
1746 DEFAULT_DOC: Respond with an error message to unidentifiable traffic
1748 Determines Squid behavior when encountering strange requests at the
1749 beginning of an accepted TCP connection or the beginning of a bumped
1750 CONNECT tunnel. Controlling Squid reaction to unexpected traffic is
1751 especially useful in interception environments where Squid is likely
1752 to see connections for unsupported protocols that Squid should either
1753 terminate or tunnel at TCP level.
1755 on_unsupported_protocol <action> [!]acl ...
1757 The first matching action wins. Only fast ACLs are supported.
1759 Supported actions are:
1761 tunnel: Establish a TCP connection with the intended server and
1762 blindly shovel TCP packets between the client and server.
1764 respond: Respond with an error message, using the transfer protocol
1765 for the Squid port that received the request (e.g., HTTP
1766 for connections intercepted at the http_port). This is the
1769 Squid expects the following traffic patterns:
1771 http_port: a plain HTTP request
1772 https_port: SSL/TLS handshake followed by an [encrypted] HTTP request
1773 ftp_port: a plain FTP command (no on_unsupported_protocol support yet!)
1774 CONNECT tunnel on http_port: same as https_port
1775 CONNECT tunnel on https_port: same as https_port
1777 Currently, this directive has effect on intercepted connections and
1778 bumped tunnels only. Other cases are not supported because Squid
1779 cannot know the intended destination of other traffic.
1782 # define what Squid errors indicate receiving non-HTTP traffic:
1783 acl foreignProtocol squid_error ERR_PROTOCOL_UNKNOWN ERR_TOO_BIG
1784 # define what Squid errors indicate receiving nothing:
1785 acl serverTalksFirstProtocol squid_error ERR_REQUEST_START_TIMEOUT
1786 # tunnel everything that does not look like HTTP:
1787 on_unsupported_protocol tunnel foreignProtocol
1788 # tunnel if we think the client waits for the server to talk first:
1789 on_unsupported_protocol tunnel serverTalksFirstProtocol
1790 # in all other error cases, just send an HTTP "error page" response:
1791 on_unsupported_protocol respond all
1793 See also: squid_error ACL
1798 -----------------------------------------------------------------------------
1801 NAME: http_port ascii_port
1806 Usage: port [mode] [options]
1807 hostname:port [mode] [options]
1808 1.2.3.4:port [mode] [options]
1810 The socket addresses where Squid will listen for HTTP client
1811 requests. You may specify multiple socket addresses.
1812 There are three forms: port alone, hostname with port, and
1813 IP address with port. If you specify a hostname or IP
1814 address, Squid binds the socket to that specific
1815 address. Most likely, you do not need to bind to a specific
1816 address, so you can use the port number alone.
1818 If you are running Squid in accelerator mode, you
1819 probably want to listen on port 80 also, or instead.
1821 The -a command line option may be used to specify additional
1822 port(s) where Squid listens for proxy request. Such ports will
1823 be plain proxy ports with no options.
1825 You may specify multiple socket addresses on multiple lines.
1829 intercept Support for IP-Layer NAT interception delivering
1830 traffic to this Squid port.
1831 NP: disables authentication on the port.
1833 tproxy Support Linux TPROXY (or BSD divert-to) with spoofing
1834 of outgoing connections using the client IP address.
1835 NP: disables authentication on the port.
1837 accel Accelerator / reverse proxy mode
1839 ssl-bump For each CONNECT request allowed by ssl_bump ACLs,
1840 establish secure connection with the client and with
1841 the server, decrypt HTTPS messages as they pass through
1842 Squid, and treat them as unencrypted HTTP messages,
1843 becoming the man-in-the-middle.
1845 The ssl_bump option is required to fully enable
1846 bumping of CONNECT requests.
1848 Omitting the mode flag causes default forward proxy mode to be used.
1851 Accelerator Mode Options:
1853 defaultsite=domainname
1854 What to use for the Host: header if it is not present
1855 in a request. Determines what site (not origin server)
1856 accelerators should consider the default.
1858 no-vhost Disable using HTTP/1.1 Host header for virtual domain support.
1860 protocol= Protocol to reconstruct accelerated and intercepted
1861 requests with. Defaults to HTTP/1.1 for http_port and
1862 HTTPS/1.1 for https_port.
1863 When an unsupported value is configured Squid will
1864 produce a FATAL error.
1865 Values: HTTP or HTTP/1.1, HTTPS or HTTPS/1.1
1867 vport Virtual host port support. Using the http_port number
1868 instead of the port passed on Host: headers.
1870 vport=NN Virtual host port support. Using the specified port
1871 number instead of the port passed on Host: headers.
1874 Act as if this Squid is the origin server.
1875 This currently means generate new Date: and Expires:
1876 headers on HIT instead of adding Age:.
1878 ignore-cc Ignore request Cache-Control headers.
1880 WARNING: This option violates HTTP specifications if
1881 used in non-accelerator setups.
1883 allow-direct Allow direct forwarding in accelerator mode. Normally
1884 accelerated requests are denied direct forwarding as if
1885 never_direct was used.
1887 WARNING: this option opens accelerator mode to security
1888 vulnerabilities usually only affecting in interception
1889 mode. Make sure to protect forwarding with suitable
1890 http_access rules when using this.
1893 SSL Bump Mode Options:
1894 In addition to these options ssl-bump requires TLS/SSL options.
1896 generate-host-certificates[=<on|off>]
1897 Dynamically create SSL server certificates for the
1898 destination hosts of bumped CONNECT requests.When
1899 enabled, the cert and key options are used to sign
1900 generated certificates. Otherwise generated
1901 certificate will be selfsigned.
1902 If there is a CA certificate lifetime of the generated
1903 certificate equals lifetime of the CA certificate. If
1904 generated certificate is selfsigned lifetime is three
1906 This option is enabled by default when ssl-bump is used.
1907 See the ssl-bump option above for more information.
1909 dynamic_cert_mem_cache_size=SIZE
1910 Approximate total RAM size spent on cached generated
1911 certificates. If set to zero, caching is disabled. The
1912 default value is 4MB.
1916 cert= Path to SSL certificate (PEM format).
1918 key= Path to SSL private key file (PEM format)
1919 if not specified, the certificate file is
1920 assumed to be a combined certificate and
1923 cipher= Colon separated list of supported ciphers.
1924 NOTE: some ciphers such as EDH ciphers depend on
1925 additional settings. If those settings are
1926 omitted the ciphers may be silently ignored
1927 by the OpenSSL library.
1929 options= Various SSL implementation options. The most important
1932 NO_SSLv3 Disallow the use of SSLv3
1934 NO_TLSv1 Disallow the use of TLSv1.0
1936 NO_TLSv1_1 Disallow the use of TLSv1.1
1938 NO_TLSv1_2 Disallow the use of TLSv1.2
1941 Always create a new key when using
1942 temporary/ephemeral DH key exchanges
1945 Enable ephemeral ECDH key exchange.
1946 The adopted curve should be specified
1947 using the tls-dh option.
1950 Disable use of RFC5077 session tickets.
1951 Some servers may have problems
1952 understanding the TLS extension due
1953 to ambiguous specification in RFC4507.
1955 ALL Enable various bug workarounds
1956 suggested as "harmless" by OpenSSL
1957 Be warned that this reduces SSL/TLS
1958 strength to some attacks.
1960 See the OpenSSL SSL_CTX_set_options documentation for a
1963 clientca= File containing the list of CAs to use when
1964 requesting a client certificate.
1966 cafile= File containing additional CA certificates to
1967 use when verifying client certificates. If unset
1968 clientca will be used.
1970 capath= Directory containing additional CA certificates
1971 and CRL lists to use when verifying client certificates.
1973 crlfile= File of additional CRL lists to use when verifying
1974 the client certificate, in addition to CRLs stored in
1975 the capath. Implies VERIFY_CRL flag below.
1978 File containing DH parameters for temporary/ephemeral DH key
1979 exchanges, optionally prefixed by a curve for ephemeral ECDH
1981 See OpenSSL documentation for details on how to create the
1982 DH parameter file. Supported curves for ECDH can be listed
1983 using the "openssl ecparam -list_curves" command.
1984 WARNING: EDH and EECDH ciphers will be silently disabled if
1985 this option is not set.
1987 sslflags= Various flags modifying the use of SSL:
1989 Don't request client certificates
1990 immediately, but wait until acl processing
1991 requires a certificate (not yet implemented).
1993 Don't use the default CA lists built in
1996 Don't allow for session reuse. Each connection
1997 will result in a new SSL session.
1999 Verify CRL lists when accepting client
2002 Verify CRL lists for all certificates in the
2003 client certificate chain.
2005 sslcontext= SSL session ID context identifier.
2009 connection-auth[=on|off]
2010 use connection-auth=off to tell Squid to prevent
2011 forwarding Microsoft connection oriented authentication
2012 (NTLM, Negotiate and Kerberos)
2014 disable-pmtu-discovery=
2015 Control Path-MTU discovery usage:
2016 off lets OS decide on what to do (default).
2017 transparent disable PMTU discovery when transparent
2019 always disable always PMTU discovery.
2021 In many setups of transparently intercepting proxies
2022 Path-MTU discovery can not work on traffic towards the
2023 clients. This is the case when the intercepting device
2024 does not fully track connections and fails to forward
2025 ICMP must fragment messages to the cache server. If you
2026 have such setup and experience that certain clients
2027 sporadically hang or never complete requests set
2028 disable-pmtu-discovery option to 'transparent'.
2030 name= Specifies a internal name for the port. Defaults to
2031 the port specification (port or addr:port)
2033 tcpkeepalive[=idle,interval,timeout]
2034 Enable TCP keepalive probes of idle connections.
2035 In seconds; idle is the initial time before TCP starts
2036 probing the connection, interval how often to probe, and
2037 timeout the time before giving up.
2039 require-proxy-header
2040 Require PROXY protocol version 1 or 2 connections.
2041 The proxy_protocol_access is required to whitelist
2042 downstream proxies which can be trusted.
2044 If you run Squid on a dual-homed machine with an internal
2045 and an external interface we recommend you to specify the
2046 internal address:port in http_port. This way Squid will only be
2047 visible on the internal address.
2051 # Squid normally listens to port 3128
2052 http_port @DEFAULT_HTTP_PORT@
2062 Usage: [ip:]port cert=certificate.pem [key=key.pem] [mode] [options...]
2064 The socket address where Squid will listen for client requests made
2065 over TLS or SSL connections. Commonly referred to as HTTPS.
2067 This is most useful for situations where you are running squid in
2068 accelerator mode and you want to do the SSL work at the accelerator level.
2070 You may specify multiple socket addresses on multiple lines,
2071 each with their own SSL certificate and/or options.
2075 accel Accelerator / reverse proxy mode
2077 intercept Support for IP-Layer interception of
2078 outgoing requests without browser settings.
2079 NP: disables authentication and IPv6 on the port.
2081 tproxy Support Linux TPROXY for spoofing outgoing
2082 connections using the client IP address.
2083 NP: disables authentication and maybe IPv6 on the port.
2085 ssl-bump For each intercepted connection allowed by ssl_bump
2086 ACLs, establish a secure connection with the client and with
2087 the server, decrypt HTTPS messages as they pass through
2088 Squid, and treat them as unencrypted HTTP messages,
2089 becoming the man-in-the-middle.
2091 An "ssl_bump server-first" match is required to
2092 fully enable bumping of intercepted SSL connections.
2094 Requires tproxy or intercept.
2096 Omitting the mode flag causes default forward proxy mode to be used.
2099 See http_port for a list of generic options
2104 cert= Path to SSL certificate (PEM format).
2106 key= Path to SSL private key file (PEM format)
2107 if not specified, the certificate file is
2108 assumed to be a combined certificate and
2111 cipher= Colon separated list of supported ciphers.
2113 options= Various SSL engine options. The most important
2116 NO_SSLv3 Disallow the use of SSLv3
2118 NO_TLSv1 Disallow the use of TLSv1.0
2120 NO_TLSv1_1 Disallow the use of TLSv1.1
2122 NO_TLSv1_2 Disallow the use of TLSv1.2
2125 Always create a new key when using
2126 temporary/ephemeral DH key exchanges
2129 Enable ephemeral ECDH key exchange.
2130 The adopted curve should be specified
2131 using the tls-dh option.
2134 Disable use of RFC5077 session tickets.
2135 Some servers may have problems
2136 understanding the TLS extension due
2137 to ambiguous specification in RFC4507.
2139 ALL Enable various bug workarounds
2140 suggested as "harmless" by OpenSSL
2141 Be warned that this reduces SSL/TLS
2142 strength to some attacks.
2144 See the OpenSSL SSL_CTX_set_options documentation for a
2147 clientca= File containing the list of CAs to use when
2148 requesting a client certificate.
2150 cafile= File containing additional CA certificates to
2151 use when verifying client certificates. If unset
2152 clientca will be used.
2154 capath= Directory containing additional CA certificates
2155 and CRL lists to use when verifying client certificates.
2157 crlfile= File of additional CRL lists to use when verifying
2158 the client certificate, in addition to CRLs stored in
2159 the capath. Implies VERIFY_CRL flag below.
2162 File containing DH parameters for temporary/ephemeral DH key
2163 exchanges, optionally prefixed by a curve for ephemeral ECDH
2166 sslflags= Various flags modifying the use of SSL:
2168 Don't request client certificates
2169 immediately, but wait until acl processing
2170 requires a certificate (not yet implemented).
2172 Don't use the default CA lists built in
2175 Don't allow for session reuse. Each connection
2176 will result in a new SSL session.
2178 Verify CRL lists when accepting client
2181 Verify CRL lists for all certificates in the
2182 client certificate chain.
2184 sslcontext= SSL session ID context identifier.
2186 generate-host-certificates[=<on|off>]
2187 Dynamically create SSL server certificates for the
2188 destination hosts of bumped SSL requests.When
2189 enabled, the cert and key options are used to sign
2190 generated certificates. Otherwise generated
2191 certificate will be selfsigned.
2192 If there is CA certificate life time of generated
2193 certificate equals lifetime of CA certificate. If
2194 generated certificate is selfsigned lifetime is three
2196 This option is enabled by default when SslBump is used.
2197 See the sslBump option above for more information.
2199 dynamic_cert_mem_cache_size=SIZE
2200 Approximate total RAM size spent on cached generated
2201 certificates. If set to zero, caching is disabled. The
2202 default value is 4MB.
2204 See http_port for a list of available options.
2212 Enables Native FTP proxy by specifying the socket address where Squid
2213 listens for FTP client requests. See http_port directive for various
2214 ways to specify the listening address and mode.
2216 Usage: ftp_port address [mode] [options]
2218 WARNING: This is a new, experimental, complex feature that has seen
2219 limited production exposure. Some Squid modules (e.g., caching) do not
2220 currently work with native FTP proxying, and many features have not
2221 even been tested for compatibility. Test well before deploying!
2223 Native FTP proxying differs substantially from proxying HTTP requests
2224 with ftp:// URIs because Squid works as an FTP server and receives
2225 actual FTP commands (rather than HTTP requests with FTP URLs).
2227 Native FTP commands accepted at ftp_port are internally converted or
2228 wrapped into HTTP-like messages. The same happens to Native FTP
2229 responses received from FTP origin servers. Those HTTP-like messages
2230 are shoveled through regular access control and adaptation layers
2231 between the FTP client and the FTP origin server. This allows Squid to
2232 examine, adapt, block, and log FTP exchanges. Squid reuses most HTTP
2233 mechanisms when shoveling wrapped FTP messages. For example,
2234 http_access and adaptation_access directives are used.
2238 intercept Same as http_port intercept. The FTP origin address is
2239 determined based on the intended destination of the
2240 intercepted connection.
2242 tproxy Support Linux TPROXY for spoofing outgoing
2243 connections using the client IP address.
2244 NP: disables authentication and maybe IPv6 on the port.
2246 By default (i.e., without an explicit mode option), Squid extracts the
2247 FTP origin address from the login@origin parameter of the FTP USER
2248 command. Many popular FTP clients support such native FTP proxying.
2252 name=token Specifies an internal name for the port. Defaults to
2253 the port address. Usable with myportname ACL.
2256 Enables tracking of FTP directories by injecting extra
2257 PWD commands and adjusting Request-URI (in wrapping
2258 HTTP requests) to reflect the current FTP server
2259 directory. Tracking is disabled by default.
2261 protocol=FTP Protocol to reconstruct accelerated and intercepted
2262 requests with. Defaults to FTP. No other accepted
2263 values have been tested with. An unsupported value
2264 results in a FATAL error. Accepted values are FTP,
2265 HTTP (or HTTP/1.1), and HTTPS (or HTTPS/1.1).
2267 Other http_port modes and options that are not specific to HTTP and
2268 HTTPS may also work.
2271 NAME: tcp_outgoing_tos tcp_outgoing_ds tcp_outgoing_dscp
2274 LOC: Ip::Qos::TheConfig.tosToServer
2276 Allows you to select a TOS/Diffserv value for packets outgoing
2277 on the server side, based on an ACL.
2279 tcp_outgoing_tos ds-field [!]aclname ...
2281 Example where normal_service_net uses the TOS value 0x00
2282 and good_service_net uses 0x20
2284 acl normal_service_net src 10.0.0.0/24
2285 acl good_service_net src 10.0.1.0/24
2286 tcp_outgoing_tos 0x00 normal_service_net
2287 tcp_outgoing_tos 0x20 good_service_net
2289 TOS/DSCP values really only have local significance - so you should
2290 know what you're specifying. For more information, see RFC2474,
2291 RFC2475, and RFC3260.
2293 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
2294 "default" to use whatever default your host has.
2295 Note that only multiples of 4 are usable as the two rightmost bits have
2296 been redefined for use by ECN (RFC 3168 section 23.1).
2297 The squid parser will enforce this by masking away the ECN bits.
2299 Processing proceeds in the order specified, and stops at first fully
2302 Only fast ACLs are supported.
2305 NAME: clientside_tos
2308 LOC: Ip::Qos::TheConfig.tosToClient
2310 Allows you to select a TOS/DSCP value for packets being transmitted
2311 on the client-side, based on an ACL.
2313 clientside_tos ds-field [!]aclname ...
2315 Example where normal_service_net uses the TOS value 0x00
2316 and good_service_net uses 0x20
2318 acl normal_service_net src 10.0.0.0/24
2319 acl good_service_net src 10.0.1.0/24
2320 clientside_tos 0x00 normal_service_net
2321 clientside_tos 0x20 good_service_net
2323 Note: This feature is incompatible with qos_flows. Any TOS values set here
2324 will be overwritten by TOS values in qos_flows.
2326 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
2327 "default" to use whatever default your host has.
2328 Note that only multiples of 4 are usable as the two rightmost bits have
2329 been redefined for use by ECN (RFC 3168 section 23.1).
2330 The squid parser will enforce this by masking away the ECN bits.
2334 NAME: tcp_outgoing_mark
2336 IFDEF: SO_MARK&&USE_LIBCAP
2338 LOC: Ip::Qos::TheConfig.nfmarkToServer
2340 Allows you to apply a Netfilter mark value to outgoing packets
2341 on the server side, based on an ACL.
2343 tcp_outgoing_mark mark-value [!]aclname ...
2345 Example where normal_service_net uses the mark value 0x00
2346 and good_service_net uses 0x20
2348 acl normal_service_net src 10.0.0.0/24
2349 acl good_service_net src 10.0.1.0/24
2350 tcp_outgoing_mark 0x00 normal_service_net
2351 tcp_outgoing_mark 0x20 good_service_net
2353 Only fast ACLs are supported.
2356 NAME: clientside_mark
2358 IFDEF: SO_MARK&&USE_LIBCAP
2360 LOC: Ip::Qos::TheConfig.nfmarkToClient
2362 Allows you to apply a Netfilter mark value to packets being transmitted
2363 on the client-side, based on an ACL.
2365 clientside_mark mark-value [!]aclname ...
2367 Example where normal_service_net uses the mark value 0x00
2368 and good_service_net uses 0x20
2370 acl normal_service_net src 10.0.0.0/24
2371 acl good_service_net src 10.0.1.0/24
2372 clientside_mark 0x00 normal_service_net
2373 clientside_mark 0x20 good_service_net
2375 Note: This feature is incompatible with qos_flows. Any mark values set here
2376 will be overwritten by mark values in qos_flows.
2383 LOC: Ip::Qos::TheConfig
2385 Allows you to select a TOS/DSCP value to mark outgoing
2386 connections to the client, based on where the reply was sourced.
2387 For platforms using netfilter, allows you to set a netfilter mark
2388 value instead of, or in addition to, a TOS value.
2390 By default this functionality is disabled. To enable it with the default
2391 settings simply use "qos_flows mark" or "qos_flows tos". Default
2392 settings will result in the netfilter mark or TOS value being copied
2393 from the upstream connection to the client. Note that it is the connection
2394 CONNMARK value not the packet MARK value that is copied.
2396 It is not currently possible to copy the mark or TOS value from the
2397 client to the upstream connection request.
2399 TOS values really only have local significance - so you should
2400 know what you're specifying. For more information, see RFC2474,
2401 RFC2475, and RFC3260.
2403 The TOS/DSCP byte must be exactly that - a octet value 0 - 255.
2404 Note that only multiples of 4 are usable as the two rightmost bits have
2405 been redefined for use by ECN (RFC 3168 section 23.1).
2406 The squid parser will enforce this by masking away the ECN bits.
2408 Mark values can be any unsigned 32-bit integer value.
2410 This setting is configured by setting the following values:
2412 tos|mark Whether to set TOS or netfilter mark values
2414 local-hit=0xFF Value to mark local cache hits.
2416 sibling-hit=0xFF Value to mark hits from sibling peers.
2418 parent-hit=0xFF Value to mark hits from parent peers.
2420 miss=0xFF[/mask] Value to mark cache misses. Takes precedence
2421 over the preserve-miss feature (see below), unless
2422 mask is specified, in which case only the bits
2423 specified in the mask are written.
2425 The TOS variant of the following features are only possible on Linux
2426 and require your kernel to be patched with the TOS preserving ZPH
2427 patch, available from http://zph.bratcheda.org
2428 No patch is needed to preserve the netfilter mark, which will work
2429 with all variants of netfilter.
2431 disable-preserve-miss
2432 This option disables the preservation of the TOS or netfilter
2433 mark. By default, the existing TOS or netfilter mark value of
2434 the response coming from the remote server will be retained
2435 and masked with miss-mark.
2436 NOTE: in the case of a netfilter mark, the mark must be set on
2437 the connection (using the CONNMARK target) not on the packet
2441 Allows you to mask certain bits in the TOS or mark value
2442 received from the remote server, before copying the value to
2443 the TOS sent towards clients.
2444 Default for tos: 0xFF (TOS from server is not changed).
2445 Default for mark: 0xFFFFFFFF (mark from server is not changed).
2447 All of these features require the --enable-zph-qos compilation flag
2448 (enabled by default). Netfilter marking also requires the
2449 libnetfilter_conntrack libraries (--with-netfilter-conntrack) and
2450 libcap 2.09+ (--with-libcap).
2454 NAME: tcp_outgoing_address
2457 DEFAULT_DOC: Address selection is performed by the operating system.
2458 LOC: Config.accessList.outgoing_address
2460 Allows you to map requests to different outgoing IP addresses
2461 based on the username or source address of the user making
2464 tcp_outgoing_address ipaddr [[!]aclname] ...
2467 Forwarding clients with dedicated IPs for certain subnets.
2469 acl normal_service_net src 10.0.0.0/24
2470 acl good_service_net src 10.0.2.0/24
2472 tcp_outgoing_address 2001:db8::c001 good_service_net
2473 tcp_outgoing_address 10.1.0.2 good_service_net
2475 tcp_outgoing_address 2001:db8::beef normal_service_net
2476 tcp_outgoing_address 10.1.0.1 normal_service_net
2478 tcp_outgoing_address 2001:db8::1
2479 tcp_outgoing_address 10.1.0.3
2481 Processing proceeds in the order specified, and stops at first fully
2484 Squid will add an implicit IP version test to each line.
2485 Requests going to IPv4 websites will use the outgoing 10.1.0.* addresses.
2486 Requests going to IPv6 websites will use the outgoing 2001:db8:* addresses.
2489 NOTE: The use of this directive using client dependent ACLs is
2490 incompatible with the use of server side persistent connections. To
2491 ensure correct results it is best to set server_persistent_connections
2492 to off when using this directive in such configurations.
2494 NOTE: The use of this directive to set a local IP on outgoing TCP links
2495 is incompatible with using TPROXY to set client IP out outbound TCP links.
2496 When needing to contact peers use the no-tproxy cache_peer option and the
2497 client_dst_passthru directive re-enable normal forwarding such as this.
2501 NAME: host_verify_strict
2504 LOC: Config.onoff.hostStrictVerify
2506 Regardless of this option setting, when dealing with intercepted
2507 traffic, Squid always verifies that the destination IP address matches
2508 the Host header domain or IP (called 'authority form URL').
2510 This enforcement is performed to satisfy a MUST-level requirement in
2511 RFC 2616 section 14.23: "The Host field value MUST represent the naming
2512 authority of the origin server or gateway given by the original URL".
2515 Squid always responds with an HTTP 409 (Conflict) error
2516 page and logs a security warning if there is no match.
2518 Squid verifies that the destination IP address matches
2519 the Host header for forward-proxy and reverse-proxy traffic
2520 as well. For those traffic types, Squid also enables the
2521 following checks, comparing the corresponding Host header
2522 and Request-URI components:
2524 * The host names (domain or IP) must be identical,
2525 but valueless or missing Host header disables all checks.
2526 For the two host names to match, both must be either IP
2529 * Port numbers must be identical, but if a port is missing
2530 the scheme-default port is assumed.
2533 When set to OFF (the default):
2534 Squid allows suspicious requests to continue but logs a
2535 security warning and blocks caching of the response.
2537 * Forward-proxy traffic is not checked at all.
2539 * Reverse-proxy traffic is not checked at all.
2541 * Intercepted traffic which passes verification is handled
2542 according to client_dst_passthru.
2544 * Intercepted requests which fail verification are sent
2545 to the client original destination instead of DIRECT.
2546 This overrides 'client_dst_passthru off'.
2548 For now suspicious intercepted CONNECT requests are always
2549 responded to with an HTTP 409 (Conflict) error page.
2554 As described in CVE-2009-0801 when the Host: header alone is used
2555 to determine the destination of a request it becomes trivial for
2556 malicious scripts on remote websites to bypass browser same-origin
2557 security policy and sandboxing protections.
2559 The cause of this is that such applets are allowed to perform their
2560 own HTTP stack, in which case the same-origin policy of the browser
2561 sandbox only verifies that the applet tries to contact the same IP
2562 as from where it was loaded at the IP level. The Host: header may
2563 be different from the connected IP and approved origin.
2567 NAME: client_dst_passthru
2570 LOC: Config.onoff.client_dst_passthru
2572 With NAT or TPROXY intercepted traffic Squid may pass the request
2573 directly to the original client destination IP or seek a faster
2574 source using the HTTP Host header.
2576 Using Host to locate alternative servers can provide faster
2577 connectivity with a range of failure recovery options.
2578 But can also lead to connectivity trouble when the client and
2579 server are attempting stateful interactions unaware of the proxy.
2581 This option (on by default) prevents alternative DNS entries being
2582 located to send intercepted traffic DIRECT to an origin server.
2583 The clients original destination IP and port will be used instead.
2585 Regardless of this option setting, when dealing with intercepted
2586 traffic Squid will verify the Host: header and any traffic which
2587 fails Host verification will be treated as if this option were ON.
2589 see host_verify_strict for details on the verification process.
2594 -----------------------------------------------------------------------------
2597 NAME: tls_outgoing_options
2598 IFDEF: USE_GNUTLS||USE_OPENSSL
2599 TYPE: securePeerOptions
2600 DEFAULT: min-version=1.0
2601 LOC: Security::ProxyOutgoingConfig
2603 disable Do not support https:// URLs.
2605 cert=/path/to/client/certificate
2606 A client TLS certificate to use when connecting.
2608 key=/path/to/client/private_key
2609 The private TLS key corresponding to the cert= above.
2610 If key= is not specified cert= is assumed to reference
2611 a PEM file containing both the certificate and the key.
2613 cipher=... The list of valid TLS ciphers to use.
2616 The minimum TLS protocol version to permit.
2617 To control SSLv3 use the options= parameter.
2618 Supported Values: 1.0 (default), 1.1, 1.2
2620 options=... Specify various TLS/SSL implementation options:
2622 NO_SSLv3 Disallow the use of SSLv3
2624 NO_TLSv1 Disallow the use of TLSv1.0
2626 NO_TLSv1_1 Disallow the use of TLSv1.1
2628 NO_TLSv1_2 Disallow the use of TLSv1.2
2631 Always create a new key when using
2632 temporary/ephemeral DH key exchanges
2635 Disable use of RFC5077 session tickets.
2636 Some servers may have problems
2637 understanding the TLS extension due
2638 to ambiguous specification in RFC4507.
2640 ALL Enable various bug workarounds
2641 suggested as "harmless" by OpenSSL
2642 Be warned that this reduces SSL/TLS
2643 strength to some attacks.
2645 See the OpenSSL SSL_CTX_set_options documentation for a
2648 cafile=... A file containing additional CA certificates to use
2649 when verifying the peer certificate.
2651 capath=... A directory containing additional CA certificates to
2652 use when verifying the peer certificate.
2654 crlfile=... A certificate revocation list file to use when
2655 verifying the peer certificate.
2657 flags=... Specify various flags modifying the TLS implementation:
2660 Accept certificates even if they fail to
2663 Don't use the default CA list built in
2666 Don't verify the peer certificate
2667 matches the server name
2669 domain= The peer name as advertised in its certificate.
2670 Used for verifying the correctness of the received peer
2671 certificate. If not specified the peer hostname will be
2677 -----------------------------------------------------------------------------
2680 NAME: ssl_unclean_shutdown
2684 LOC: Config.SSL.unclean_shutdown
2686 Some browsers (especially MSIE) bugs out on SSL shutdown
2693 LOC: Config.SSL.ssl_engine
2696 The OpenSSL engine to use. You will need to set this if you
2697 would like to use hardware SSL acceleration for example.
2700 NAME: sslproxy_session_ttl
2703 LOC: Config.SSL.session_ttl
2706 Sets the timeout value for SSL sessions
2709 NAME: sslproxy_session_cache_size
2712 LOC: Config.SSL.sessionCacheSize
2715 Sets the cache size to use for ssl session
2718 NAME: sslproxy_cert_sign_hash
2721 LOC: Config.SSL.certSignHash
2724 Sets the hashing algorithm to use when signing generated certificates.
2725 Valid algorithm names depend on the OpenSSL library used. The following
2726 names are usually available: sha1, sha256, sha512, and md5. Please see
2727 your OpenSSL library manual for the available hashes. By default, Squids
2728 that support this option use sha256 hashes.
2730 Squid does not forcefully purge cached certificates that were generated
2731 with an algorithm other than the currently configured one. They remain
2732 in the cache, subject to the regular cache eviction policy, and become
2733 useful if the algorithm changes again.
2738 TYPE: sslproxy_ssl_bump
2739 LOC: Config.accessList.ssl_bump
2740 DEFAULT_DOC: Become a TCP tunnel without decrypting proxied traffic.
2743 This option is consulted when a CONNECT request is received on
2744 an http_port (or a new connection is intercepted at an
2745 https_port), provided that port was configured with an ssl-bump
2746 flag. The subsequent data on the connection is either treated as
2747 HTTPS and decrypted OR tunneled at TCP level without decryption,
2748 depending on the first matching bumping "action".
2750 ssl_bump <action> [!]acl ...
2752 The following bumping actions are currently supported:
2755 Become a TCP tunnel without decrypting proxied traffic.
2756 This is the default action.
2759 Establish a secure connection with the server and, using a
2760 mimicked server certificate, with the client.
2763 Receive client (step SslBump1) or server (step SslBump2)
2764 certificate while preserving the possibility of splicing the
2765 connection. Peeking at the server certificate (during step 2)
2766 usually precludes bumping of the connection at step 3.
2769 Receive client (step SslBump1) or server (step SslBump2)
2770 certificate while preserving the possibility of bumping the
2771 connection. Staring at the server certificate (during step 2)
2772 usually precludes splicing of the connection at step 3.
2775 Close client and server connections.
2777 Backward compatibility actions available at step SslBump1:
2780 Bump the connection. Establish a secure connection with the
2781 client first, then connect to the server. This old mode does
2782 not allow Squid to mimic server SSL certificate and does not
2783 work with intercepted SSL connections.
2786 Bump the connection. Establish a secure connection with the
2787 server first, then establish a secure connection with the
2788 client, using a mimicked server certificate. Works with both
2789 CONNECT requests and intercepted SSL connections, but does
2790 not allow to make decisions based on SSL handshake info.
2793 Decide whether to bump or splice the connection based on
2794 client-to-squid and server-to-squid SSL hello messages.
2798 Same as the "splice" action.
2800 All ssl_bump rules are evaluated at each of the supported bumping
2801 steps. Rules with actions that are impossible at the current step are
2802 ignored. The first matching ssl_bump action wins and is applied at the
2803 end of the current step. If no rules match, the splice action is used.
2804 See the at_step ACL for a list of the supported SslBump steps.
2806 This clause supports both fast and slow acl types.
2807 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2809 See also: http_port ssl-bump, https_port ssl-bump, and acl at_step.
2812 # Example: Bump all requests except those originating from
2813 # localhost or those going to example.com.
2815 acl broken_sites dstdomain .example.com
2816 ssl_bump splice localhost
2817 ssl_bump splice broken_sites
2821 NAME: sslproxy_cert_error
2824 DEFAULT_DOC: Server certificate errors terminate the transaction.
2825 LOC: Config.ssl_client.cert_error
2828 Use this ACL to bypass server certificate validation errors.
2830 For example, the following lines will bypass all validation errors
2831 when talking to servers for example.com. All other
2832 validation errors will result in ERR_SECURE_CONNECT_FAIL error.
2834 acl BrokenButTrustedServers dstdomain example.com
2835 sslproxy_cert_error allow BrokenButTrustedServers
2836 sslproxy_cert_error deny all
2838 This clause only supports fast acl types.
2839 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2840 Using slow acl types may result in server crashes
2842 Without this option, all server certificate validation errors
2843 terminate the transaction to protect Squid and the client.
2845 SQUID_X509_V_ERR_INFINITE_VALIDATION error cannot be bypassed
2846 but should not happen unless your OpenSSL library is buggy.
2849 Bypassing validation errors is dangerous because an
2850 error usually implies that the server cannot be trusted
2851 and the connection may be insecure.
2853 See also: sslproxy_flags and DONT_VERIFY_PEER.
2856 NAME: sslproxy_cert_sign
2859 POSTSCRIPTUM: signUntrusted ssl::certUntrusted
2860 POSTSCRIPTUM: signSelf ssl::certSelfSigned
2861 POSTSCRIPTUM: signTrusted all
2862 TYPE: sslproxy_cert_sign
2863 LOC: Config.ssl_client.cert_sign
2866 sslproxy_cert_sign <signing algorithm> acl ...
2868 The following certificate signing algorithms are supported:
2871 Sign using the configured CA certificate which is usually
2872 placed in and trusted by end-user browsers. This is the
2873 default for trusted origin server certificates.
2876 Sign to guarantee an X509_V_ERR_CERT_UNTRUSTED browser error.
2877 This is the default for untrusted origin server certificates
2878 that are not self-signed (see ssl::certUntrusted).
2881 Sign using a self-signed certificate with the right CN to
2882 generate a X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT error in the
2883 browser. This is the default for self-signed origin server
2884 certificates (see ssl::certSelfSigned).
2886 This clause only supports fast acl types.
2888 When sslproxy_cert_sign acl(s) match, Squid uses the corresponding
2889 signing algorithm to generate the certificate and ignores all
2890 subsequent sslproxy_cert_sign options (the first match wins). If no
2891 acl(s) match, the default signing algorithm is determined by errors
2892 detected when obtaining and validating the origin server certificate.
2894 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2895 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2896 CONNECT request that carries a domain name. In all other cases (CONNECT
2897 to an IP address or an intercepted SSL connection), Squid cannot detect
2898 the domain mismatch at certificate generation time when
2899 bump-server-first is used.
2902 NAME: sslproxy_cert_adapt
2905 TYPE: sslproxy_cert_adapt
2906 LOC: Config.ssl_client.cert_adapt
2909 sslproxy_cert_adapt <adaptation algorithm> acl ...
2911 The following certificate adaptation algorithms are supported:
2914 Sets the "Not After" property to the "Not After" property of
2915 the CA certificate used to sign generated certificates.
2918 Sets the "Not Before" property to the "Not Before" property of
2919 the CA certificate used to sign generated certificates.
2921 setCommonName or setCommonName{CN}
2922 Sets Subject.CN property to the host name specified as a
2923 CN parameter or, if no explicit CN parameter was specified,
2924 extracted from the CONNECT request. It is a misconfiguration
2925 to use setCommonName without an explicit parameter for
2926 intercepted or tproxied SSL connections.
2928 This clause only supports fast acl types.
2930 Squid first groups sslproxy_cert_adapt options by adaptation algorithm.
2931 Within a group, when sslproxy_cert_adapt acl(s) match, Squid uses the
2932 corresponding adaptation algorithm to generate the certificate and
2933 ignores all subsequent sslproxy_cert_adapt options in that algorithm's
2934 group (i.e., the first match wins within each algorithm group). If no
2935 acl(s) match, the default mimicking action takes place.
2937 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2938 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2939 CONNECT request that carries a domain name. In all other cases (CONNECT
2940 to an IP address or an intercepted SSL connection), Squid cannot detect
2941 the domain mismatch at certificate generation time when
2942 bump-server-first is used.
2945 NAME: sslpassword_program
2948 LOC: Config.Program.ssl_password
2951 Specify a program used for entering SSL key passphrases
2952 when using encrypted SSL certificate keys. If not specified
2953 keys must either be unencrypted, or Squid started with the -N
2954 option to allow it to query interactively for the passphrase.
2956 The key file name is given as argument to the program allowing
2957 selection of the right password if you have multiple encrypted
2962 OPTIONS RELATING TO EXTERNAL SSL_CRTD
2963 -----------------------------------------------------------------------------
2966 NAME: sslcrtd_program
2969 DEFAULT: @DEFAULT_SSL_CRTD@ -s @DEFAULT_SSL_DB_DIR@ -M 4MB
2970 LOC: Ssl::TheConfig.ssl_crtd
2972 Specify the location and options of the executable for ssl_crtd process.
2973 @DEFAULT_SSL_CRTD@ program requires -s and -M parameters
2974 For more information use:
2975 @DEFAULT_SSL_CRTD@ -h
2978 NAME: sslcrtd_children
2979 TYPE: HelperChildConfig
2981 DEFAULT: 32 startup=5 idle=1
2982 LOC: Ssl::TheConfig.ssl_crtdChildren
2984 The maximum number of processes spawn to service ssl server.
2985 The maximum this may be safely set to is 32.
2987 The startup= and idle= options allow some measure of skew in your
2992 Sets the minimum number of processes to spawn when Squid
2993 starts or reconfigures. When set to zero the first request will
2994 cause spawning of the first child process to handle it.
2996 Starting too few children temporary slows Squid under load while it
2997 tries to spawn enough additional processes to cope with traffic.
3001 Sets a minimum of how many processes Squid is to try and keep available
3002 at all times. When traffic begins to rise above what the existing
3003 processes can handle this many more will be spawned up to the maximum
3004 configured. A minimum setting of 1 is required.
3008 Sets the maximum number of queued requests.
3009 If the queued requests exceed queue size for more than 3 minutes
3010 squid aborts its operation.
3011 The default value is set to 2*numberofchildren.
3013 You must have at least one ssl_crtd process.
3016 NAME: sslcrtvalidator_program
3020 LOC: Ssl::TheConfig.ssl_crt_validator
3022 Specify the location and options of the executable for ssl_crt_validator
3025 Usage: sslcrtvalidator_program [ttl=n] [cache=n] path ...
3028 ttl=n TTL in seconds for cached results. The default is 60 secs
3029 cache=n limit the result cache size. The default value is 2048
3032 NAME: sslcrtvalidator_children
3033 TYPE: HelperChildConfig
3035 DEFAULT: 32 startup=5 idle=1 concurrency=1
3036 LOC: Ssl::TheConfig.ssl_crt_validator_Children
3038 The maximum number of processes spawn to service SSL server.
3039 The maximum this may be safely set to is 32.
3041 The startup= and idle= options allow some measure of skew in your
3046 Sets the minimum number of processes to spawn when Squid
3047 starts or reconfigures. When set to zero the first request will
3048 cause spawning of the first child process to handle it.
3050 Starting too few children temporary slows Squid under load while it
3051 tries to spawn enough additional processes to cope with traffic.
3055 Sets a minimum of how many processes Squid is to try and keep available
3056 at all times. When traffic begins to rise above what the existing
3057 processes can handle this many more will be spawned up to the maximum
3058 configured. A minimum setting of 1 is required.
3062 The number of requests each certificate validator helper can handle in
3063 parallel. A value of 0 indicates the certficate validator does not
3064 support concurrency. Defaults to 1.
3066 When this directive is set to a value >= 1 then the protocol
3067 used to communicate with the helper is modified to include
3068 a request ID in front of the request/response. The request
3069 ID from the request must be echoed back with the response
3074 Sets the maximum number of queued requests.
3075 If the queued requests exceed queue size for more than 3 minutes
3076 squid aborts its operation.
3077 The default value is set to 2*numberofchildren.
3079 You must have at least one ssl_crt_validator process.
3083 OPTIONS WHICH AFFECT THE NEIGHBOR SELECTION ALGORITHM
3084 -----------------------------------------------------------------------------
3092 To specify other caches in a hierarchy, use the format:
3094 cache_peer hostname type http-port icp-port [options]
3099 # hostname type port port options
3100 # -------------------- -------- ----- ----- -----------
3101 cache_peer parent.foo.net parent 3128 3130 default
3102 cache_peer sib1.foo.net sibling 3128 3130 proxy-only
3103 cache_peer sib2.foo.net sibling 3128 3130 proxy-only
3104 cache_peer example.com parent 80 0 default
3105 cache_peer cdn.example.com sibling 3128 0
3107 type: either 'parent', 'sibling', or 'multicast'.
3109 proxy-port: The port number where the peer accept HTTP requests.
3110 For other Squid proxies this is usually 3128
3111 For web servers this is usually 80
3113 icp-port: Used for querying neighbor caches about objects.
3114 Set to 0 if the peer does not support ICP or HTCP.
3115 See ICP and HTCP options below for additional details.
3118 ==== ICP OPTIONS ====
3120 You MUST also set icp_port and icp_access explicitly when using these options.
3121 The defaults will prevent peer traffic using ICP.
3124 no-query Disable ICP queries to this neighbor.
3127 Indicates the named peer is a member of a multicast group.
3128 ICP queries will not be sent directly to the peer, but ICP
3129 replies will be accepted from it.
3131 closest-only Indicates that, for ICP_OP_MISS replies, we'll only forward
3132 CLOSEST_PARENT_MISSes and never FIRST_PARENT_MISSes.
3135 To only send ICP queries to this neighbor infrequently.
3136 This is used to keep the neighbor round trip time updated
3137 and is usually used in conjunction with weighted-round-robin.
3140 ==== HTCP OPTIONS ====
3142 You MUST also set htcp_port and htcp_access explicitly when using these options.
3143 The defaults will prevent peer traffic using HTCP.
3146 htcp Send HTCP, instead of ICP, queries to the neighbor.
3147 You probably also want to set the "icp-port" to 4827
3148 instead of 3130. This directive accepts a comma separated
3149 list of options described below.
3151 htcp=oldsquid Send HTCP to old Squid versions (2.5 or earlier).
3153 htcp=no-clr Send HTCP to the neighbor but without
3154 sending any CLR requests. This cannot be used with
3157 htcp=only-clr Send HTCP to the neighbor but ONLY CLR requests.
3158 This cannot be used with no-clr.
3161 Send HTCP to the neighbor including CLRs but only when
3162 they do not result from PURGE requests.
3165 Forward any HTCP CLR requests this proxy receives to the peer.
3168 ==== PEER SELECTION METHODS ====
3170 The default peer selection method is ICP, with the first responding peer
3171 being used as source. These options can be used for better load balancing.
3174 default This is a parent cache which can be used as a "last-resort"
3175 if a peer cannot be located by any of the peer-selection methods.
3176 If specified more than once, only the first is used.
3178 round-robin Load-Balance parents which should be used in a round-robin
3179 fashion in the absence of any ICP queries.
3180 weight=N can be used to add bias.
3182 weighted-round-robin
3183 Load-Balance parents which should be used in a round-robin
3184 fashion with the frequency of each parent being based on the
3185 round trip time. Closer parents are used more often.
3186 Usually used for background-ping parents.
3187 weight=N can be used to add bias.
3189 carp Load-Balance parents which should be used as a CARP array.
3190 The requests will be distributed among the parents based on the
3191 CARP load balancing hash function based on their weight.
3193 userhash Load-balance parents based on the client proxy_auth or ident username.
3195 sourcehash Load-balance parents based on the client source IP.
3198 To be used only for cache peers of type "multicast".
3199 ALL members of this multicast group have "sibling"
3200 relationship with it, not "parent". This is to a multicast
3201 group when the requested object would be fetched only from
3202 a "parent" cache, anyway. It's useful, e.g., when
3203 configuring a pool of redundant Squid proxies, being
3204 members of the same multicast group.
3207 ==== PEER SELECTION OPTIONS ====
3209 weight=N use to affect the selection of a peer during any weighted
3210 peer-selection mechanisms.
3211 The weight must be an integer; default is 1,
3212 larger weights are favored more.
3213 This option does not affect parent selection if a peering
3214 protocol is not in use.
3216 basetime=N Specify a base amount to be subtracted from round trip
3218 It is subtracted before division by weight in calculating
3219 which parent to fectch from. If the rtt is less than the
3220 base time the rtt is set to a minimal value.
3222 ttl=N Specify a TTL to use when sending multicast ICP queries
3224 Only useful when sending to a multicast group.
3225 Because we don't accept ICP replies from random
3226 hosts, you must configure other group members as
3227 peers with the 'multicast-responder' option.
3229 no-delay To prevent access to this neighbor from influencing the
3232 digest-url=URL Tell Squid to fetch the cache digest (if digests are
3233 enabled) for this host from the specified URL rather
3234 than the Squid default location.
3237 ==== CARP OPTIONS ====
3239 carp-key=key-specification
3240 use a different key than the full URL to hash against the peer.
3241 the key-specification is a comma-separated list of the keywords
3242 scheme, host, port, path, params
3243 Order is not important.
3245 ==== ACCELERATOR / REVERSE-PROXY OPTIONS ====
3247 originserver Causes this parent to be contacted as an origin server.
3248 Meant to be used in accelerator setups when the peer
3252 Set the Host header of requests forwarded to this peer.
3253 Useful in accelerator setups where the server (peer)
3254 expects a certain domain name but clients may request
3255 others. ie example.com or www.example.com
3257 no-digest Disable request of cache digests.
3260 Disables requesting ICMP RTT database (NetDB).
3263 ==== AUTHENTICATION OPTIONS ====
3266 If this is a personal/workgroup proxy and your parent
3267 requires proxy authentication.
3269 Note: The string can include URL escapes (i.e. %20 for
3270 spaces). This also means % must be written as %%.
3273 Send login details received from client to this peer.
3274 Both Proxy- and WWW-Authorization headers are passed
3275 without alteration to the peer.
3276 Authentication is not required by Squid for this to work.
3278 Note: This will pass any form of authentication but
3279 only Basic auth will work through a proxy unless the
3280 connection-auth options are also used.
3282 login=PASS Send login details received from client to this peer.
3283 Authentication is not required by this option.
3285 If there are no client-provided authentication headers
3286 to pass on, but username and password are available
3287 from an external ACL user= and password= result tags
3288 they may be sent instead.
3290 Note: To combine this with proxy_auth both proxies must
3291 share the same user database as HTTP only allows for
3292 a single login (one for proxy, one for origin server).
3293 Also be warned this will expose your users proxy
3294 password to the peer. USE WITH CAUTION
3297 Send the username to the upstream cache, but with a
3298 fixed password. This is meant to be used when the peer
3299 is in another administrative domain, but it is still
3300 needed to identify each user.
3301 The star can optionally be followed by some extra
3302 information which is added to the username. This can
3303 be used to identify this proxy to the peer, similar to
3304 the login=username:password option above.
3307 If this is a personal/workgroup proxy and your parent
3308 requires a secure proxy authentication.
3309 The first principal from the default keytab or defined by
3310 the environment variable KRB5_KTNAME will be used.
3312 WARNING: The connection may transmit requests from multiple
3313 clients. Negotiate often assumes end-to-end authentication
3314 and a single-client. Which is not strictly true here.
3316 login=NEGOTIATE:principal_name
3317 If this is a personal/workgroup proxy and your parent
3318 requires a secure proxy authentication.
3319 The principal principal_name from the default keytab or
3320 defined by the environment variable KRB5_KTNAME will be
3323 WARNING: The connection may transmit requests from multiple
3324 clients. Negotiate often assumes end-to-end authentication
3325 and a single-client. Which is not strictly true here.
3327 connection-auth=on|off
3328 Tell Squid that this peer does or not support Microsoft
3329 connection oriented authentication, and any such
3330 challenges received from there should be ignored.
3331 Default is auto to automatically determine the status
3335 ==== SSL / HTTPS / TLS OPTIONS ====
3337 ssl Encrypt connections to this peer with SSL/TLS.
3339 sslcert=/path/to/ssl/certificate
3340 A client SSL certificate to use when connecting to
3343 sslkey=/path/to/ssl/key
3344 The private SSL key corresponding to sslcert above.
3345 If 'sslkey' is not specified 'sslcert' is assumed to
3346 reference a combined file containing both the
3347 certificate and the key.
3349 sslcipher=... The list of valid SSL ciphers to use when connecting
3353 The minimum TLS protocol version to permit. To control
3354 SSLv3 use the ssloptions= parameter.
3355 Supported Values: 1.0 (default), 1.1, 1.2
3357 ssloptions=... Specify various SSL implementation options:
3359 NO_SSLv3 Disallow the use of SSLv3
3361 NO_TLSv1 Disallow the use of TLSv1.0
3363 NO_TLSv1_1 Disallow the use of TLSv1.1
3365 NO_TLSv1_2 Disallow the use of TLSv1.2
3368 Always create a new key when using
3369 temporary/ephemeral DH key exchanges
3372 Disable use of RFC5077 session tickets.
3373 Some servers may have problems
3374 understanding the TLS extension due
3375 to ambiguous specification in RFC4507.
3377 ALL Enable various bug workarounds
3378 suggested as "harmless" by OpenSSL
3379 Be warned that this reduces SSL/TLS
3380 strength to some attacks.
3382 See the OpenSSL SSL_CTX_set_options documentation for a
3385 sslcafile=... A file containing additional CA certificates to use
3386 when verifying the peer certificate.
3388 sslcapath=... A directory containing additional CA certificates to
3389 use when verifying the peer certificate.
3391 sslcrlfile=... A certificate revocation list file to use when
3392 verifying the peer certificate.
3394 sslflags=... Specify various flags modifying the SSL implementation:
3397 Accept certificates even if they fail to
3401 Don't use the default CA list built in
3405 Don't verify the peer certificate
3406 matches the server name
3408 ssldomain= The peer name as advertised in it's certificate.
3409 Used for verifying the correctness of the received peer
3410 certificate. If not specified the peer hostname will be
3414 Enable the "Front-End-Https: On" header needed when
3415 using Squid as a SSL frontend in front of Microsoft OWA.
3416 See MS KB document Q307347 for details on this header.
3417 If set to auto the header will only be added if the
3418 request is forwarded as a https:// URL.
3421 ==== GENERAL OPTIONS ====
3424 A peer-specific connect timeout.
3425 Also see the peer_connect_timeout directive.
3427 connect-fail-limit=N
3428 How many times connecting to a peer must fail before
3429 it is marked as down. Standby connection failures
3430 count towards this limit. Default is 10.
3432 allow-miss Disable Squid's use of only-if-cached when forwarding
3433 requests to siblings. This is primarily useful when
3434 icp_hit_stale is used by the sibling. To extensive use
3435 of this option may result in forwarding loops, and you
3436 should avoid having two-way peerings with this option.
3437 For example to deny peer usage on requests from peer
3438 by denying cache_peer_access if the source is a peer.
3440 max-conn=N Limit the number of concurrent connections the Squid
3441 may open to this peer, including already opened idle
3442 and standby connections. There is no peer-specific
3443 connection limit by default.
3445 A peer exceeding the limit is not used for new
3446 requests unless a standby connection is available.
3448 max-conn currently works poorly with idle persistent
3449 connections: When a peer reaches its max-conn limit,
3450 and there are idle persistent connections to the peer,
3451 the peer may not be selected because the limiting code
3452 does not know whether Squid can reuse those idle
3455 standby=N Maintain a pool of N "hot standby" connections to an
3456 UP peer, available for requests when no idle
3457 persistent connection is available (or safe) to use.
3458 By default and with zero N, no such pool is maintained.
3459 N must not exceed the max-conn limit (if any).
3461 At start or after reconfiguration, Squid opens new TCP
3462 standby connections until there are N connections
3463 available and then replenishes the standby pool as
3464 opened connections are used up for requests. A used
3465 connection never goes back to the standby pool, but
3466 may go to the regular idle persistent connection pool
3467 shared by all peers and origin servers.
3469 Squid never opens multiple new standby connections
3470 concurrently. This one-at-a-time approach minimizes
3471 flooding-like effect on peers. Furthermore, just a few
3472 standby connections should be sufficient in most cases
3473 to supply most new requests with a ready-to-use
3476 Standby connections obey server_idle_pconn_timeout.
3477 For the feature to work as intended, the peer must be
3478 configured to accept and keep them open longer than
3479 the idle timeout at the connecting Squid, to minimize
3480 race conditions typical to idle used persistent
3481 connections. Default request_timeout and
3482 server_idle_pconn_timeout values ensure such a
3485 name=xxx Unique name for the peer.
3486 Required if you have multiple peers on the same host
3487 but different ports.
3488 This name can be used in cache_peer_access and similar
3489 directives to dentify the peer.
3490 Can be used by outgoing access controls through the
3493 no-tproxy Do not use the client-spoof TPROXY support when forwarding
3494 requests to this peer. Use normal address selection instead.
3495 This overrides the spoof_client_ip ACL.
3497 proxy-only objects fetched from the peer will not be stored locally.
3501 NAME: cache_peer_access
3506 Use to limit the requests for which a neighbor proxy will be
3507 queried. Peers with no restrictions are queried for all requests.
3510 cache_peer_access cache-host allow|deny [!]aclname ...
3512 The syntax is identical to 'http_access' and the other lists of
3513 ACL elements. See the comments for 'http_access', or the
3514 Squid FAQ (http://wiki.squid-cache.org/SquidFaq/SquidAcl).
3517 NAME: neighbor_type_domain
3518 TYPE: hostdomaintype
3520 DEFAULT_DOC: The peer type from cache_peer directive is used for all requests to that peer.
3523 Modify the cache_peer neighbor type when passing requests
3524 about specific domains to the peer.
3527 neighbor_type_domain neighbor parent|sibling domain domain ...
3530 cache_peer foo.example.com parent 3128 3130
3531 neighbor_type_domain foo.example.com sibling .au .de
3533 The above configuration treats all requests to foo.example.com as a
3534 parent proxy unless the request is for a .au or .de ccTLD domain name.
3537 NAME: dead_peer_timeout
3541 LOC: Config.Timeout.deadPeer
3543 This controls how long Squid waits to declare a peer cache
3544 as "dead." If there are no ICP replies received in this
3545 amount of time, Squid will declare the peer dead and not
3546 expect to receive any further ICP replies. However, it
3547 continues to send ICP queries, and will mark the peer as
3548 alive upon receipt of the first subsequent ICP reply.
3550 This timeout also affects when Squid expects to receive ICP
3551 replies from peers. If more than 'dead_peer' seconds have
3552 passed since the last ICP reply was received, Squid will not
3553 expect to receive an ICP reply on the next query. Thus, if
3554 your time between requests is greater than this timeout, you
3555 will see a lot of requests sent DIRECT to origin servers
3556 instead of to your parents.
3559 NAME: forward_max_tries
3562 LOC: Config.forward_max_tries
3564 Controls how many different forward paths Squid will try
3565 before giving up. See also forward_timeout.
3567 NOTE: connect_retries (default: none) can make each of these
3568 possible forwarding paths be tried multiple times.
3572 MEMORY CACHE OPTIONS
3573 -----------------------------------------------------------------------------
3580 LOC: Config.memMaxSize
3582 NOTE: THIS PARAMETER DOES NOT SPECIFY THE MAXIMUM PROCESS SIZE.
3583 IT ONLY PLACES A LIMIT ON HOW MUCH ADDITIONAL MEMORY SQUID WILL
3584 USE AS A MEMORY CACHE OF OBJECTS. SQUID USES MEMORY FOR OTHER
3585 THINGS AS WELL. SEE THE SQUID FAQ SECTION 8 FOR DETAILS.
3587 'cache_mem' specifies the ideal amount of memory to be used
3589 * In-Transit objects
3591 * Negative-Cached objects
3593 Data for these objects are stored in 4 KB blocks. This
3594 parameter specifies the ideal upper limit on the total size of
3595 4 KB blocks allocated. In-Transit objects take the highest
3598 In-transit objects have priority over the others. When
3599 additional space is needed for incoming data, negative-cached
3600 and hot objects will be released. In other words, the
3601 negative-cached and hot objects will fill up any unused space
3602 not needed for in-transit objects.
3604 If circumstances require, this limit will be exceeded.
3605 Specifically, if your incoming request rate requires more than
3606 'cache_mem' of memory to hold in-transit objects, Squid will
3607 exceed this limit to satisfy the new requests. When the load
3608 decreases, blocks will be freed until the high-water mark is
3609 reached. Thereafter, blocks will be used to store hot
3612 If shared memory caching is enabled, Squid does not use the shared
3613 cache space for in-transit objects, but they still consume as much
3614 local memory as they need. For more details about the shared memory
3615 cache, see memory_cache_shared.
3618 NAME: maximum_object_size_in_memory
3622 LOC: Config.Store.maxInMemObjSize
3624 Objects greater than this size will not be attempted to kept in
3625 the memory cache. This should be set high enough to keep objects
3626 accessed frequently in memory to improve performance whilst low
3627 enough to keep larger objects from hoarding cache_mem.
3630 NAME: memory_cache_shared
3633 LOC: Config.memShared
3635 DEFAULT_DOC: "on" where supported if doing memory caching with multiple SMP workers.
3637 Controls whether the memory cache is shared among SMP workers.
3639 The shared memory cache is meant to occupy cache_mem bytes and replace
3640 the non-shared memory cache, although some entities may still be
3641 cached locally by workers for now (e.g., internal and in-transit
3642 objects may be served from a local memory cache even if shared memory
3643 caching is enabled).
3645 By default, the memory cache is shared if and only if all of the
3646 following conditions are satisfied: Squid runs in SMP mode with
3647 multiple workers, cache_mem is positive, and Squid environment
3648 supports required IPC primitives (e.g., POSIX shared memory segments
3649 and GCC-style atomic operations).
3651 To avoid blocking locks, shared memory uses opportunistic algorithms
3652 that do not guarantee that every cachable entity that could have been
3653 shared among SMP workers will actually be shared.
3655 Currently, entities exceeding 32KB in size cannot be shared.
3658 NAME: memory_cache_mode
3662 DEFAULT_DOC: Keep the most recently fetched objects in memory
3664 Controls which objects to keep in the memory cache (cache_mem)
3666 always Keep most recently fetched objects in memory (default)
3668 disk Only disk cache hits are kept in memory, which means
3669 an object must first be cached on disk and then hit
3670 a second time before cached in memory.
3672 network Only objects fetched from network is kept in memory
3675 NAME: memory_replacement_policy
3677 LOC: Config.memPolicy
3680 The memory replacement policy parameter determines which
3681 objects are purged from memory when memory space is needed.
3683 See cache_replacement_policy for details on algorithms.
3688 -----------------------------------------------------------------------------
3691 NAME: cache_replacement_policy
3693 LOC: Config.replPolicy
3696 The cache replacement policy parameter determines which
3697 objects are evicted (replaced) when disk space is needed.
3699 lru : Squid's original list based LRU policy
3700 heap GDSF : Greedy-Dual Size Frequency
3701 heap LFUDA: Least Frequently Used with Dynamic Aging
3702 heap LRU : LRU policy implemented using a heap
3704 Applies to any cache_dir lines listed below this directive.
3706 The LRU policies keeps recently referenced objects.
3708 The heap GDSF policy optimizes object hit rate by keeping smaller
3709 popular objects in cache so it has a better chance of getting a
3710 hit. It achieves a lower byte hit rate than LFUDA though since
3711 it evicts larger (possibly popular) objects.
3713 The heap LFUDA policy keeps popular objects in cache regardless of
3714 their size and thus optimizes byte hit rate at the expense of
3715 hit rate since one large, popular object will prevent many
3716 smaller, slightly less popular objects from being cached.
3718 Both policies utilize a dynamic aging mechanism that prevents
3719 cache pollution that can otherwise occur with frequency-based
3720 replacement policies.
3722 NOTE: if using the LFUDA replacement policy you should increase
3723 the value of maximum_object_size above its default of 4 MB to
3724 to maximize the potential byte hit rate improvement of LFUDA.
3726 For more information about the GDSF and LFUDA cache replacement
3727 policies see http://www.hpl.hp.com/techreports/1999/HPL-1999-69.html
3728 and http://fog.hpl.external.hp.com/techreports/98/HPL-98-173.html.
3731 NAME: minimum_object_size
3735 DEFAULT_DOC: no limit
3736 LOC: Config.Store.minObjectSize
3738 Objects smaller than this size will NOT be saved on disk. The
3739 value is specified in bytes, and the default is 0 KB, which
3740 means all responses can be stored.
3743 NAME: maximum_object_size
3747 LOC: Config.Store.maxObjectSize
3749 Set the default value for max-size parameter on any cache_dir.
3750 The value is specified in bytes, and the default is 4 MB.
3752 If you wish to get a high BYTES hit ratio, you should probably
3753 increase this (one 32 MB object hit counts for 3200 10KB
3756 If you wish to increase hit ratio more than you want to
3757 save bandwidth you should leave this low.
3759 NOTE: if using the LFUDA replacement policy you should increase
3760 this value to maximize the byte hit rate improvement of LFUDA!
3761 See cache_replacement_policy for a discussion of this policy.
3767 DEFAULT_DOC: No disk cache. Store cache ojects only in memory.
3768 LOC: Config.cacheSwap
3771 cache_dir Type Directory-Name Fs-specific-data [options]
3773 You can specify multiple cache_dir lines to spread the
3774 cache among different disk partitions.
3776 Type specifies the kind of storage system to use. Only "ufs"
3777 is built by default. To enable any of the other storage systems
3778 see the --enable-storeio configure option.
3780 'Directory' is a top-level directory where cache swap
3781 files will be stored. If you want to use an entire disk
3782 for caching, this can be the mount-point directory.
3783 The directory must exist and be writable by the Squid
3784 process. Squid will NOT create this directory for you.
3786 In SMP configurations, cache_dir must not precede the workers option
3787 and should use configuration macros or conditionals to give each
3788 worker interested in disk caching a dedicated cache directory.
3791 ==== The ufs store type ====
3793 "ufs" is the old well-known Squid storage format that has always
3797 cache_dir ufs Directory-Name Mbytes L1 L2 [options]
3799 'Mbytes' is the amount of disk space (MB) to use under this
3800 directory. The default is 100 MB. Change this to suit your
3801 configuration. Do NOT put the size of your disk drive here.
3802 Instead, if you want Squid to use the entire disk drive,
3803 subtract 20% and use that value.
3805 'L1' is the number of first-level subdirectories which
3806 will be created under the 'Directory'. The default is 16.
3808 'L2' is the number of second-level subdirectories which
3809 will be created under each first-level directory. The default
3813 ==== The aufs store type ====
3815 "aufs" uses the same storage format as "ufs", utilizing
3816 POSIX-threads to avoid blocking the main Squid process on
3817 disk-I/O. This was formerly known in Squid as async-io.
3820 cache_dir aufs Directory-Name Mbytes L1 L2 [options]
3822 see argument descriptions under ufs above
3825 ==== The diskd store type ====
3827 "diskd" uses the same storage format as "ufs", utilizing a
3828 separate process to avoid blocking the main Squid process on
3832 cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n]
3834 see argument descriptions under ufs above
3836 Q1 specifies the number of unacknowledged I/O requests when Squid
3837 stops opening new files. If this many messages are in the queues,
3838 Squid won't open new files. Default is 64
3840 Q2 specifies the number of unacknowledged messages when Squid
3841 starts blocking. If this many messages are in the queues,
3842 Squid blocks until it receives some replies. Default is 72
3844 When Q1 < Q2 (the default), the cache directory is optimized
3845 for lower response time at the expense of a decrease in hit
3846 ratio. If Q1 > Q2, the cache directory is optimized for
3847 higher hit ratio at the expense of an increase in response
3851 ==== The rock store type ====
3854 cache_dir rock Directory-Name Mbytes [options]
3856 The Rock Store type is a database-style storage. All cached
3857 entries are stored in a "database" file, using fixed-size slots.
3858 A single entry occupies one or more slots.
3860 If possible, Squid using Rock Store creates a dedicated kid
3861 process called "disker" to avoid blocking Squid worker(s) on disk
3862 I/O. One disker kid is created for each rock cache_dir. Diskers
3863 are created only when Squid, running in daemon mode, has support
3864 for the IpcIo disk I/O module.
3866 swap-timeout=msec: Squid will not start writing a miss to or
3867 reading a hit from disk if it estimates that the swap operation
3868 will take more than the specified number of milliseconds. By
3869 default and when set to zero, disables the disk I/O time limit
3870 enforcement. Ignored when using blocking I/O module because
3871 blocking synchronous I/O does not allow Squid to estimate the
3872 expected swap wait time.
3874 max-swap-rate=swaps/sec: Artificially limits disk access using
3875 the specified I/O rate limit. Swap out requests that
3876 would cause the average I/O rate to exceed the limit are
3877 delayed. Individual swap in requests (i.e., hits or reads) are
3878 not delayed, but they do contribute to measured swap rate and
3879 since they are placed in the same FIFO queue as swap out
3880 requests, they may wait longer if max-swap-rate is smaller.
3881 This is necessary on file systems that buffer "too
3882 many" writes and then start blocking Squid and other processes
3883 while committing those writes to disk. Usually used together
3884 with swap-timeout to avoid excessive delays and queue overflows
3885 when disk demand exceeds available disk "bandwidth". By default
3886 and when set to zero, disables the disk I/O rate limit
3887 enforcement. Currently supported by IpcIo module only.
3889 slot-size=bytes: The size of a database "record" used for
3890 storing cached responses. A cached response occupies at least
3891 one slot and all database I/O is done using individual slots so
3892 increasing this parameter leads to more disk space waste while
3893 decreasing it leads to more disk I/O overheads. Should be a
3894 multiple of your operating system I/O page size. Defaults to
3895 16KBytes. A housekeeping header is stored with each slot and
3896 smaller slot-sizes will be rejected. The header is smaller than
3900 ==== COMMON OPTIONS ====
3902 no-store no new objects should be stored to this cache_dir.
3904 min-size=n the minimum object size in bytes this cache_dir
3905 will accept. It's used to restrict a cache_dir
3906 to only store large objects (e.g. AUFS) while
3907 other stores are optimized for smaller objects
3911 max-size=n the maximum object size in bytes this cache_dir
3913 The value in maximum_object_size directive sets
3914 the default unless more specific details are
3915 available (ie a small store capacity).
3917 Note: To make optimal use of the max-size limits you should order
3918 the cache_dir lines with the smallest max-size value first.
3922 # Uncomment and adjust the following to add a disk cache directory.
3923 #cache_dir ufs @DEFAULT_SWAP_DIR@ 100 16 256
3927 NAME: store_dir_select_algorithm
3929 LOC: Config.store_dir_select_algorithm
3932 How Squid selects which cache_dir to use when the response
3933 object will fit into more than one.
3935 Regardless of which algorithm is used the cache_dir min-size
3936 and max-size parameters are obeyed. As such they can affect
3937 the selection algorithm by limiting the set of considered
3944 This algorithm is suited to caches with similar cache_dir
3945 sizes and disk speeds.
3947 The disk with the least I/O pending is selected.
3948 When there are multiple disks with the same I/O load ranking
3949 the cache_dir with most available capacity is selected.
3951 When a mix of cache_dir sizes are configured the faster disks
3952 have a naturally lower I/O loading and larger disks have more
3953 capacity. So space used to store objects and data throughput
3954 may be very unbalanced towards larger disks.
3959 This algorithm is suited to caches with unequal cache_dir
3962 Each cache_dir is selected in a rotation. The next suitable
3965 Available cache_dir capacity is only considered in relation
3966 to whether the object will fit and meets the min-size and
3967 max-size parameters.
3969 Disk I/O loading is only considered to prevent overload on slow
3970 disks. This algorithm does not spread objects by size, so any
3971 I/O loading per-disk may appear very unbalanced and volatile.
3973 If several cache_dirs use similar min-size, max-size, or other
3974 limits to to reject certain responses, then do not group such
3975 cache_dir lines together, to avoid round-robin selection bias
3976 towards the first cache_dir after the group. Instead, interleave
3977 cache_dir lines from different groups. For example:
3979 store_dir_select_algorithm round-robin
3980 cache_dir rock /hdd1 ... min-size=100000
3981 cache_dir rock /ssd1 ... max-size=99999
3982 cache_dir rock /hdd2 ... min-size=100000
3983 cache_dir rock /ssd2 ... max-size=99999
3984 cache_dir rock /hdd3 ... min-size=100000
3985 cache_dir rock /ssd3 ... max-size=99999
3988 NAME: max_open_disk_fds
3990 LOC: Config.max_open_disk_fds
3992 DEFAULT_DOC: no limit
3994 To avoid having disk as the I/O bottleneck Squid can optionally
3995 bypass the on-disk cache if more than this amount of disk file
3996 descriptors are open.
3998 A value of 0 indicates no limit.
4001 NAME: cache_swap_low
4002 COMMENT: (percent, 0-100)
4005 LOC: Config.Swap.lowWaterMark
4007 The low-water mark for cache object replacement.
4008 Replacement begins when the swap (disk) usage is above the
4009 low-water mark and attempts to maintain utilization near the
4010 low-water mark. As swap utilization gets close to high-water
4011 mark object eviction becomes more aggressive. If utilization is
4012 close to the low-water mark less replacement is done each time.
4014 Defaults are 90% and 95%. If you have a large cache, 5% could be
4015 hundreds of MB. If this is the case you may wish to set these
4016 numbers closer together.
4018 See also cache_swap_high
4021 NAME: cache_swap_high
4022 COMMENT: (percent, 0-100)
4025 LOC: Config.Swap.highWaterMark
4027 The high-water mark for cache object replacement.
4028 Replacement begins when the swap (disk) usage is above the
4029 low-water mark and attempts to maintain utilization near the
4030 low-water mark. As swap utilization gets close to high-water
4031 mark object eviction becomes more aggressive. If utilization is
4032 close to the low-water mark less replacement is done each time.
4034 Defaults are 90% and 95%. If you have a large cache, 5% could be
4035 hundreds of MB. If this is the case you may wish to set these
4036 numbers closer together.
4038 See also cache_swap_low
4043 -----------------------------------------------------------------------------
4050 DEFAULT_DOC: The format definitions squid, common, combined, referrer, useragent are built in.
4054 logformat <name> <format specification>
4056 Defines an access log format.
4058 The <format specification> is a string with embedded % format codes
4060 % format codes all follow the same basic structure where all but
4061 the formatcode is optional. Output strings are automatically escaped
4062 as required according to their context and the output format
4063 modifiers are usually not needed, but can be specified if an explicit
4064 output format is desired.
4066 % ["|[|'|#] [-] [[0]width] [{argument}] formatcode
4068 " output in quoted string format
4069 [ output in squid text log format as used by log_mime_hdrs
4070 # output in URL quoted format
4075 width minimum and/or maximum field width:
4076 [width_min][.width_max]
4077 When minimum starts with 0, the field is zero-padded.
4078 String values exceeding maximum width are truncated.
4080 {arg} argument such as header name etc
4084 % a literal % character
4085 sn Unique sequence number per log line entry
4086 err_code The ID of an error response served by Squid or
4087 a similar internal error identifier.
4088 err_detail Additional err_code-dependent error information.
4089 note The annotation specified by the argument. Also
4090 logs the adaptation meta headers set by the
4091 adaptation_meta configuration parameter.
4092 If no argument given all annotations logged.
4093 The argument may include a separator to use with
4096 By default, multiple note values are separated with ","
4097 and multiple notes are separated with "\r\n".
4098 When logging named notes with %{name}note, the
4099 explicitly configured separator is used between note
4100 values. When logging all notes with %note, the
4101 explicitly configured separator is used between
4102 individual notes. There is currently no way to
4103 specify both value and notes separators when logging
4104 all notes with %note.
4106 Connection related format codes:
4108 >a Client source IP address
4110 >p Client source port
4111 >eui Client source EUI (MAC address, EUI-48 or EUI-64 identifier)
4112 >la Local IP address the client connected to
4113 >lp Local port number the client connected to
4114 >qos Client connection TOS/DSCP value set by Squid
4115 >nfmark Client connection netfilter mark set by Squid
4117 la Local listening IP address the client connection was connected to.
4118 lp Local listening port number the client connection was connected to.
4120 <a Server IP address of the last server or peer connection
4121 <A Server FQDN or peer name
4122 <p Server port number of the last server or peer connection
4123 <la Local IP address of the last server or peer connection
4124 <lp Local port number of the last server or peer connection
4125 <qos Server connection TOS/DSCP value set by Squid
4126 <nfmark Server connection netfilter mark set by Squid
4128 Time related format codes:
4130 ts Seconds since epoch
4131 tu subsecond time (milliseconds)
4132 tl Local time. Optional strftime format argument
4133 default %d/%b/%Y:%H:%M:%S %z
4134 tg GMT time. Optional strftime format argument
4135 default %d/%b/%Y:%H:%M:%S %z
4136 tr Response time (milliseconds)
4137 dt Total time spent making DNS lookups (milliseconds)
4138 tS Approximate master transaction start time in
4139 <full seconds since epoch>.<fractional seconds> format.
4140 Currently, Squid considers the master transaction
4141 started when a complete HTTP request header initiating
4142 the transaction is received from the client. This is
4143 the same value that Squid uses to calculate transaction
4144 response time when logging %tr to access.log. Currently,
4145 Squid uses millisecond resolution for %tS values,
4146 similar to the default access.log "current time" field
4149 Access Control related format codes:
4151 et Tag returned by external acl
4152 ea Log string returned by external acl
4153 un User name (any available)
4154 ul User name from authentication
4155 ue User name from external acl helper
4156 ui User name from ident
4157 un A user name. Expands to the first available name
4158 from the following list of information sources:
4159 - authenticated user name, like %ul
4160 - user name supplied by an external ACL, like %ue
4161 - SSL client name, like %us
4162 - ident user name, like %ui
4163 credentials Client credentials. The exact meaning depends on
4164 the authentication scheme: For Basic authentication,
4165 it is the password; for Digest, the realm sent by the
4166 client; for NTLM and Negotiate, the client challenge
4167 or client credentials prefixed with "YR " or "KK ".
4169 HTTP related format codes:
4173 [http::]rm Request method (GET/POST etc)
4174 [http::]>rm Request method from client
4175 [http::]<rm Request method sent to server or peer
4176 [http::]ru Request URL from client (historic, filtered for logging)
4177 [http::]>ru Request URL from client
4178 [http::]<ru Request URL sent to server or peer
4179 [http::]>rs Request URL scheme from client
4180 [http::]<rs Request URL scheme sent to server or peer
4181 [http::]>rd Request URL domain from client
4182 [http::]<rd Request URL domain sent to server or peer
4183 [http::]>rP Request URL port from client
4184 [http::]<rP Request URL port sent to server or peer
4185 [http::]rp Request URL path excluding hostname
4186 [http::]>rp Request URL path excluding hostname from client
4187 [http::]<rp Request URL path excluding hostname sent to server or peer
4188 [http::]rv Request protocol version
4189 [http::]>rv Request protocol version from client
4190 [http::]<rv Request protocol version sent to server or peer
4192 [http::]>h Original received request header.
4193 Usually differs from the request header sent by
4194 Squid, although most fields are often preserved.
4195 Accepts optional header field name/value filter
4196 argument using name[:[separator]element] format.
4197 [http::]>ha Received request header after adaptation and
4198 redirection (pre-cache REQMOD vectoring point).
4199 Usually differs from the request header sent by
4200 Squid, although most fields are often preserved.
4201 Optional header name argument as for >h
4206 [http::]<Hs HTTP status code received from the next hop
4207 [http::]>Hs HTTP status code sent to the client
4209 [http::]<h Reply header. Optional header name argument
4212 [http::]mt MIME content type
4217 [http::]st Total size of request + reply traffic with client
4218 [http::]>st Total size of request received from client.
4219 Excluding chunked encoding bytes.
4220 [http::]<st Total size of reply sent to client (after adaptation)
4222 [http::]>sh Size of request headers received from client
4223 [http::]<sh Size of reply headers sent to client (after adaptation)
4225 [http::]<sH Reply high offset sent
4226 [http::]<sS Upstream object size
4228 [http::]<bs Number of HTTP-equivalent message body bytes
4229 received from the next hop, excluding chunked
4230 transfer encoding and control messages.
4231 Generated FTP/Gopher listings are treated as
4237 [http::]<pt Peer response time in milliseconds. The timer starts
4238 when the last request byte is sent to the next hop
4239 and stops when the last response byte is received.
4240 [http::]<tt Total time in milliseconds. The timer
4241 starts with the first connect request (or write I/O)
4242 sent to the first selected peer. The timer stops
4243 with the last I/O with the last peer.
4245 Squid handling related format codes:
4247 Ss Squid request status (TCP_MISS etc)
4248 Sh Squid hierarchy status (DEFAULT_PARENT etc)
4250 SSL-related format codes:
4252 ssl::bump_mode SslBump decision for the transaction:
4254 For CONNECT requests that initiated bumping of
4255 a connection and for any request received on
4256 an already bumped connection, Squid logs the
4257 corresponding SslBump mode ("server-first" or
4258 "client-first"). See the ssl_bump option for
4259 more information about these modes.
4261 A "none" token is logged for requests that
4262 triggered "ssl_bump" ACL evaluation matching
4263 either a "none" rule or no rules at all.
4265 In all other cases, a single dash ("-") is
4268 ssl::>sni SSL client SNI sent to Squid. Available only
4269 after the peek, stare, or splice SSL bumping
4272 If ICAP is enabled, the following code becomes available (as
4273 well as ICAP log codes documented with the icap_log option):
4275 icap::tt Total ICAP processing time for the HTTP
4276 transaction. The timer ticks when ICAP
4277 ACLs are checked and when ICAP
4278 transaction is in progress.
4280 If adaptation is enabled the following three codes become available:
4282 adapt::<last_h The header of the last ICAP response or
4283 meta-information from the last eCAP
4284 transaction related to the HTTP transaction.
4285 Like <h, accepts an optional header name
4288 adapt::sum_trs Summed adaptation transaction response
4289 times recorded as a comma-separated list in
4290 the order of transaction start time. Each time
4291 value is recorded as an integer number,
4292 representing response time of one or more
4293 adaptation (ICAP or eCAP) transaction in
4294 milliseconds. When a failed transaction is
4295 being retried or repeated, its time is not
4296 logged individually but added to the
4297 replacement (next) transaction. See also:
4300 adapt::all_trs All adaptation transaction response times.
4301 Same as adaptation_strs but response times of
4302 individual transactions are never added
4303 together. Instead, all transaction response
4304 times are recorded individually.
4306 You can prefix adapt::*_trs format codes with adaptation
4307 service name in curly braces to record response time(s) specific
4308 to that service. For example: %{my_service}adapt::sum_trs
4310 If SSL is enabled, the following formating codes become available:
4312 %ssl::>cert_subject The Subject field of the received client
4313 SSL certificate or a dash ('-') if Squid has
4314 received an invalid/malformed certificate or
4315 no certificate at all. Consider encoding the
4316 logged value because Subject often has spaces.
4318 %ssl::>cert_issuer The Issuer field of the received client
4319 SSL certificate or a dash ('-') if Squid has
4320 received an invalid/malformed certificate or
4321 no certificate at all. Consider encoding the
4322 logged value because Issuer often has spaces.
4324 The default formats available (which do not need re-defining) are:
4326 logformat squid %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %[un %Sh/%<a %mt
4327 logformat common %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st %Ss:%Sh
4328 logformat combined %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
4329 logformat referrer %ts.%03tu %>a %{Referer}>h %ru
4330 logformat useragent %>a [%tl] "%{User-Agent}>h"
4332 NOTE: When the log_mime_hdrs directive is set to ON.
4333 The squid, common and combined formats have a safely encoded copy
4334 of the mime headers appended to each line within a pair of brackets.
4336 NOTE: The common and combined formats are not quite true to the Apache definition.
4337 The logs from Squid contain an extra status and hierarchy code appended.
4341 NAME: access_log cache_access_log
4343 LOC: Config.Log.accesslogs
4344 DEFAULT_IF_NONE: daemon:@DEFAULT_ACCESS_LOG@ squid
4346 Configures whether and how Squid logs HTTP and ICP transactions.
4347 If access logging is enabled, a single line is logged for every
4348 matching HTTP or ICP request. The recommended directive formats are:
4350 access_log <module>:<place> [option ...] [acl acl ...]
4351 access_log none [acl acl ...]
4353 The following directive format is accepted but may be deprecated:
4354 access_log <module>:<place> [<logformat name> [acl acl ...]]
4356 In most cases, the first ACL name must not contain the '=' character
4357 and should not be equal to an existing logformat name. You can always
4358 start with an 'all' ACL to work around those restrictions.
4360 Will log to the specified module:place using the specified format (which
4361 must be defined in a logformat directive) those entries which match
4362 ALL the acl's specified (which must be defined in acl clauses).
4363 If no acl is specified, all requests will be logged to this destination.
4365 ===== Available options for the recommended directive format =====
4367 logformat=name Names log line format (either built-in or
4368 defined by a logformat directive). Defaults
4371 buffer-size=64KB Defines approximate buffering limit for log
4372 records (see buffered_logs). Squid should not
4373 keep more than the specified size and, hence,
4374 should flush records before the buffer becomes
4375 full to avoid overflows under normal
4376 conditions (the exact flushing algorithm is
4377 module-dependent though). The on-error option
4378 controls overflow handling.
4380 on-error=die|drop Defines action on unrecoverable errors. The
4381 'drop' action ignores (i.e., does not log)
4382 affected log records. The default 'die' action
4383 kills the affected worker. The drop action
4384 support has not been tested for modules other
4387 rotate=N Specifies the number of log file rotations to
4388 make when you run 'squid -k rotate'. The default
4389 is to obey the logfile_rotate directive. Setting
4390 rotate=0 will disable the file name rotation,
4391 but the log files are still closed and re-opened.
4392 This will enable you to rename the logfiles
4393 yourself just before sending the rotate signal.
4394 Only supported by the stdio module.
4396 ===== Modules Currently available =====
4398 none Do not log any requests matching these ACL.
4399 Do not specify Place or logformat name.
4401 stdio Write each log line to disk immediately at the completion of
4403 Place: the filename and path to be written.
4405 daemon Very similar to stdio. But instead of writing to disk the log
4406 line is passed to a daemon helper for asychronous handling instead.
4407 Place: varies depending on the daemon.
4409 log_file_daemon Place: the file name and path to be written.
4411 syslog To log each request via syslog facility.
4412 Place: The syslog facility and priority level for these entries.
4413 Place Format: facility.priority
4415 where facility could be any of:
4416 authpriv, daemon, local0 ... local7 or user.
4418 And priority could be any of:
4419 err, warning, notice, info, debug.
4421 udp To send each log line as text data to a UDP receiver.
4422 Place: The destination host name or IP and port.
4423 Place Format: //host:port
4425 tcp To send each log line as text data to a TCP receiver.
4426 Lines may be accumulated before sending (see buffered_logs).
4427 Place: The destination host name or IP and port.
4428 Place Format: //host:port
4431 access_log daemon:@DEFAULT_ACCESS_LOG@ squid
4437 LOC: Config.Log.icaplogs
4440 ICAP log files record ICAP transaction summaries, one line per
4443 The icap_log option format is:
4444 icap_log <filepath> [<logformat name> [acl acl ...]]
4445 icap_log none [acl acl ...]]
4447 Please see access_log option documentation for details. The two
4448 kinds of logs share the overall configuration approach and many
4451 ICAP processing of a single HTTP message or transaction may
4452 require multiple ICAP transactions. In such cases, multiple
4453 ICAP transaction log lines will correspond to a single access
4456 ICAP log uses logformat codes that make sense for an ICAP
4457 transaction. Header-related codes are applied to the HTTP header
4458 embedded in an ICAP server response, with the following caveats:
4459 For REQMOD, there is no HTTP response header unless the ICAP
4460 server performed request satisfaction. For RESPMOD, the HTTP
4461 request header is the header sent to the ICAP server. For
4462 OPTIONS, there are no HTTP headers.
4464 The following format codes are also available for ICAP logs:
4466 icap::<A ICAP server IP address. Similar to <A.
4468 icap::<service_name ICAP service name from the icap_service
4469 option in Squid configuration file.
4471 icap::ru ICAP Request-URI. Similar to ru.
4473 icap::rm ICAP request method (REQMOD, RESPMOD, or
4474 OPTIONS). Similar to existing rm.
4476 icap::>st Bytes sent to the ICAP server (TCP payload
4477 only; i.e., what Squid writes to the socket).
4479 icap::<st Bytes received from the ICAP server (TCP
4480 payload only; i.e., what Squid reads from
4483 icap::<bs Number of message body bytes received from the
4484 ICAP server. ICAP message body, if any, usually
4485 includes encapsulated HTTP message headers and
4486 possibly encapsulated HTTP message body. The
4487 HTTP body part is dechunked before its size is
4490 icap::tr Transaction response time (in
4491 milliseconds). The timer starts when
4492 the ICAP transaction is created and
4493 stops when the transaction is completed.
4496 icap::tio Transaction I/O time (in milliseconds). The
4497 timer starts when the first ICAP request
4498 byte is scheduled for sending. The timers
4499 stops when the last byte of the ICAP response
4502 icap::to Transaction outcome: ICAP_ERR* for all
4503 transaction errors, ICAP_OPT for OPTION
4504 transactions, ICAP_ECHO for 204
4505 responses, ICAP_MOD for message
4506 modification, and ICAP_SAT for request
4507 satisfaction. Similar to Ss.
4509 icap::Hs ICAP response status code. Similar to Hs.
4511 icap::>h ICAP request header(s). Similar to >h.
4513 icap::<h ICAP response header(s). Similar to <h.
4515 The default ICAP log format, which can be used without an explicit
4516 definition, is called icap_squid:
4518 logformat icap_squid %ts.%03tu %6icap::tr %>a %icap::to/%03icap::Hs %icap::<size %icap::rm %icap::ru% %un -/%icap::<A -
4520 See also: logformat, log_icap, and %adapt::<last_h
4523 NAME: logfile_daemon
4525 DEFAULT: @DEFAULT_LOGFILED@
4526 LOC: Log::TheConfig.logfile_daemon
4528 Specify the path to the logfile-writing daemon. This daemon is
4529 used to write the access and store logs, if configured.
4531 Squid sends a number of commands to the log daemon:
4532 L<data>\n - logfile data
4537 r<n>\n - set rotate count to <n>
4538 b<n>\n - 1 = buffer output, 0 = don't buffer output
4540 No responses is expected.
4543 NAME: stats_collection
4545 LOC: Config.accessList.stats_collection
4547 DEFAULT_DOC: Allow logging for all transactions.
4548 COMMENT: allow|deny acl acl...
4550 This options allows you to control which requests gets accounted
4551 in performance counters.
4553 This clause only supports fast acl types.
4554 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4557 NAME: cache_store_log
4560 LOC: Config.Log.store
4562 Logs the activities of the storage manager. Shows which
4563 objects are ejected from the cache, and which objects are
4564 saved and for how long.
4565 There are not really utilities to analyze this data, so you can safely
4566 disable it (the default).
4568 Store log uses modular logging outputs. See access_log for the list
4569 of modules supported.
4572 cache_store_log stdio:@DEFAULT_STORE_LOG@
4573 cache_store_log daemon:@DEFAULT_STORE_LOG@
4576 NAME: cache_swap_state cache_swap_log
4578 LOC: Config.Log.swap
4580 DEFAULT_DOC: Store the journal inside its cache_dir
4582 Location for the cache "swap.state" file. This index file holds
4583 the metadata of objects saved on disk. It is used to rebuild
4584 the cache during startup. Normally this file resides in each
4585 'cache_dir' directory, but you may specify an alternate
4586 pathname here. Note you must give a full filename, not just
4587 a directory. Since this is the index for the whole object
4588 list you CANNOT periodically rotate it!
4590 If %s can be used in the file name it will be replaced with a
4591 a representation of the cache_dir name where each / is replaced
4592 with '.'. This is needed to allow adding/removing cache_dir
4593 lines when cache_swap_log is being used.
4595 If have more than one 'cache_dir', and %s is not used in the name
4596 these swap logs will have names such as:
4602 The numbered extension (which is added automatically)
4603 corresponds to the order of the 'cache_dir' lines in this
4604 configuration file. If you change the order of the 'cache_dir'
4605 lines in this file, these index files will NOT correspond to
4606 the correct 'cache_dir' entry (unless you manually rename
4607 them). We recommend you do NOT use this option. It is
4608 better to keep these index files in each 'cache_dir' directory.
4611 NAME: logfile_rotate
4614 LOC: Config.Log.rotateNumber
4616 Specifies the default number of logfile rotations to make when you
4617 type 'squid -k rotate'. The default is 10, which will rotate
4618 with extensions 0 through 9. Setting logfile_rotate to 0 will
4619 disable the file name rotation, but the logfiles are still closed
4620 and re-opened. This will enable you to rename the logfiles
4621 yourself just before sending the rotate signal.
4623 Note, from Squid-3.1 this option is only a default for cache.log,
4624 that log can be rotated separately by using debug_options.
4626 Note, from Squid-3.6 this option is only a default for access.log
4627 recorded by stdio: module. Those logs can be rotated separately by
4628 using the rotate=N option on their access_log directive.
4630 Note, the 'squid -k rotate' command normally sends a USR1
4631 signal to the running squid process. In certain situations
4632 (e.g. on Linux with Async I/O), USR1 is used for other
4633 purposes, so -k rotate uses another signal. It is best to get
4634 in the habit of using 'squid -k rotate' instead of 'kill -USR1
4641 DEFAULT: @DEFAULT_MIME_TABLE@
4642 LOC: Config.mimeTablePathname
4644 Path to Squid's icon configuration file.
4646 You shouldn't need to change this, but the default file contains
4647 examples and formatting information if you do.
4653 LOC: Config.onoff.log_mime_hdrs
4656 The Cache can record both the request and the response MIME
4657 headers for each HTTP transaction. The headers are encoded
4658 safely and will appear as two bracketed fields at the end of
4659 the access log (for either the native or httpd-emulated log
4660 formats). To enable this logging set log_mime_hdrs to 'on'.
4665 DEFAULT: @DEFAULT_PID_FILE@
4666 LOC: Config.pidFilename
4668 A filename to write the process-id to. To disable, enter "none".
4671 NAME: client_netmask
4673 LOC: Config.Addrs.client_netmask
4675 DEFAULT_DOC: Log full client IP address
4677 A netmask for client addresses in logfiles and cachemgr output.
4678 Change this to protect the privacy of your cache clients.
4679 A netmask of 255.255.255.0 will log all IP's in that range with
4680 the last digit set to '0'.
4683 NAME: strip_query_terms
4685 LOC: Config.onoff.strip_query_terms
4688 By default, Squid strips query terms from requested URLs before
4689 logging. This protects your user's privacy and reduces log size.
4691 When investigating HIT/MISS or other caching behaviour you
4692 will need to disable this to see the full URL used by Squid.
4699 LOC: Config.onoff.buffered_logs
4701 Whether to write/send access_log records ASAP or accumulate them and
4702 then write/send them in larger chunks. Buffering may improve
4703 performance because it decreases the number of I/Os. However,
4704 buffering increases the delay before log records become available to
4705 the final recipient (e.g., a disk file or logging daemon) and,
4706 hence, increases the risk of log records loss.
4708 Note that even when buffered_logs are off, Squid may have to buffer
4709 records if it cannot write/send them immediately due to pending I/Os
4710 (e.g., the I/O writing the previous log record) or connectivity loss.
4712 Currently honored by 'daemon' and 'tcp' access_log modules only.
4715 NAME: netdb_filename
4717 DEFAULT: stdio:@DEFAULT_NETDB_FILE@
4718 LOC: Config.netdbFilename
4721 Where Squid stores it's netdb journal.
4722 When enabled this journal preserves netdb state between restarts.
4724 To disable, enter "none".
4728 OPTIONS FOR TROUBLESHOOTING
4729 -----------------------------------------------------------------------------
4734 DEFAULT_IF_NONE: @DEFAULT_CACHE_LOG@
4735 LOC: Debug::cache_log
4737 Squid administrative logging file.
4739 This is where general information about Squid behavior goes. You can
4740 increase the amount of data logged to this file and how often it is
4741 rotated with "debug_options"
4747 DEFAULT_DOC: Log all critical and important messages.
4748 LOC: Debug::debugOptions
4750 Logging options are set as section,level where each source file
4751 is assigned a unique section. Lower levels result in less
4752 output, Full debugging (level 9) can result in a very large
4753 log file, so be careful.
4755 The magic word "ALL" sets debugging levels for all sections.
4756 The default is to run with "ALL,1" to record important warnings.
4758 The rotate=N option can be used to keep more or less of these logs
4759 than would otherwise be kept by logfile_rotate.
4760 For most uses a single log should be enough to monitor current
4761 events affecting Squid.
4766 LOC: Config.coredump_dir
4767 DEFAULT_IF_NONE: none
4768 DEFAULT_DOC: Use the directory from where Squid was started.
4770 By default Squid leaves core files in the directory from where
4771 it was started. If you set 'coredump_dir' to a directory
4772 that exists, Squid will chdir() to that directory at startup
4773 and coredump files will be left there.
4777 # Leave coredumps in the first cache dir
4778 coredump_dir @DEFAULT_SWAP_DIR@
4784 OPTIONS FOR FTP GATEWAYING
4785 -----------------------------------------------------------------------------
4791 LOC: Config.Ftp.anon_user
4793 If you want the anonymous login password to be more informative
4794 (and enable the use of picky FTP servers), set this to something
4795 reasonable for your domain, like wwwuser@somewhere.net
4797 The reason why this is domainless by default is the
4798 request can be made on the behalf of a user in any domain,
4799 depending on how the cache is used.
4800 Some FTP server also validate the email address is valid
4801 (for example perl.com).
4807 LOC: Config.Ftp.passive
4809 If your firewall does not allow Squid to use passive
4810 connections, turn off this option.
4812 Use of ftp_epsv_all option requires this to be ON.
4818 LOC: Config.Ftp.epsv_all
4820 FTP Protocol extensions permit the use of a special "EPSV ALL" command.
4822 NATs may be able to put the connection on a "fast path" through the
4823 translator, as the EPRT command will never be used and therefore,
4824 translation of the data portion of the segments will never be needed.
4826 When a client only expects to do two-way FTP transfers this may be
4828 If squid finds that it must do a three-way FTP transfer after issuing
4829 an EPSV ALL command, the FTP session will fail.
4831 If you have any doubts about this option do not use it.
4832 Squid will nicely attempt all other connection methods.
4834 Requires ftp_passive to be ON (default) for any effect.
4840 LOC: Config.accessList.ftp_epsv
4842 FTP Protocol extensions permit the use of a special "EPSV" command.
4844 NATs may be able to put the connection on a "fast path" through the
4845 translator using EPSV, as the EPRT command will never be used
4846 and therefore, translation of the data portion of the segments
4847 will never be needed.
4849 EPSV is often required to interoperate with FTP servers on IPv6
4850 networks. On the other hand, it may break some IPv4 servers.
4852 By default, EPSV may try EPSV with any FTP server. To fine tune
4853 that decision, you may restrict EPSV to certain clients or servers
4856 ftp_epsv allow|deny al1 acl2 ...
4858 WARNING: Disabling EPSV may cause problems with external NAT and IPv6.
4860 Only fast ACLs are supported.
4861 Requires ftp_passive to be ON (default) for any effect.
4867 LOC: Config.Ftp.eprt
4869 FTP Protocol extensions permit the use of a special "EPRT" command.
4871 This extension provides a protocol neutral alternative to the
4872 IPv4-only PORT command. When supported it enables active FTP data
4873 channels over IPv6 and efficient NAT handling.
4875 Turning this OFF will prevent EPRT being attempted and will skip
4876 straight to using PORT for IPv4 servers.
4878 Some devices are known to not handle this extension correctly and
4879 may result in crashes. Devices which suport EPRT enough to fail
4880 cleanly will result in Squid attempting PORT anyway. This directive
4881 should only be disabled when EPRT results in device failures.
4883 WARNING: Doing so will convert Squid back to the old behavior with all
4884 the related problems with external NAT devices/layers and IPv4-only FTP.
4887 NAME: ftp_sanitycheck
4890 LOC: Config.Ftp.sanitycheck
4892 For security and data integrity reasons Squid by default performs
4893 sanity checks of the addresses of FTP data connections ensure the
4894 data connection is to the requested server. If you need to allow
4895 FTP connections to servers using another IP address for the data
4896 connection turn this off.
4899 NAME: ftp_telnet_protocol
4902 LOC: Config.Ftp.telnet
4904 The FTP protocol is officially defined to use the telnet protocol
4905 as transport channel for the control connection. However, many
4906 implementations are broken and does not respect this aspect of
4909 If you have trouble accessing files with ASCII code 255 in the
4910 path or similar problems involving this ASCII code you can
4911 try setting this directive to off. If that helps, report to the
4912 operator of the FTP server in question that their FTP server
4913 is broken and does not follow the FTP standard.
4917 OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
4918 -----------------------------------------------------------------------------
4923 DEFAULT: @DEFAULT_DISKD@
4924 LOC: Config.Program.diskd
4926 Specify the location of the diskd executable.
4927 Note this is only useful if you have compiled in
4928 diskd as one of the store io modules.
4931 NAME: unlinkd_program
4934 DEFAULT: @DEFAULT_UNLINKD@
4935 LOC: Config.Program.unlinkd
4937 Specify the location of the executable for file deletion process.
4940 NAME: pinger_program
4943 DEFAULT: @DEFAULT_PINGER@
4946 Specify the location of the executable for the pinger process.
4955 Control whether the pinger is active at run-time.
4956 Enables turning ICMP pinger on and off with a simple
4957 squid -k reconfigure.
4962 OPTIONS FOR URL REWRITING
4963 -----------------------------------------------------------------------------
4966 NAME: url_rewrite_program redirect_program
4968 LOC: Config.Program.redirect
4971 Specify the location of the executable URL rewriter to use.
4972 Since they can perform almost any function there isn't one included.
4974 For each requested URL, the rewriter will receive on line with the format
4976 [channel-ID <SP>] URL [<SP> extras]<NL>
4978 See url_rewrite_extras on how to send "extras" with optional values to
4980 After processing the request the helper must reply using the following format:
4982 [channel-ID <SP>] result [<SP> kv-pairs]
4984 The result code can be:
4986 OK status=30N url="..."
4987 Redirect the URL to the one supplied in 'url='.
4988 'status=' is optional and contains the status code to send
4989 the client in Squids HTTP response. It must be one of the
4990 HTTP redirect status codes: 301, 302, 303, 307, 308.
4991 When no status is given Squid will use 302.
4993 OK rewrite-url="..."
4994 Rewrite the URL to the one supplied in 'rewrite-url='.
4995 The new URL is fetched directly by Squid and returned to
4996 the client as the response to its request.
4999 When neither of url= and rewrite-url= are sent Squid does
5003 Do not change the URL.
5006 An internal error occurred in the helper, preventing
5007 a result being identified. The 'message=' key name is
5008 reserved for delivering a log message.
5011 In addition to the above kv-pairs Squid also understands the following
5012 optional kv-pairs received from URL rewriters:
5014 Associates a TAG with the client TCP connection.
5015 The TAG is treated as a regular annotation but persists across
5016 future requests on the client connection rather than just the
5017 current request. A helper may update the TAG during subsequent
5018 requests be returning a new kv-pair.
5020 When using the concurrency= option the protocol is changed by
5021 introducing a query channel tag in front of the request/response.
5022 The query channel tag is a number between 0 and concurrency-1.
5023 This value must be echoed back unchanged to Squid as the first part
5024 of the response relating to its request.
5026 WARNING: URL re-writing ability should be avoided whenever possible.
5027 Use the URL redirect form of response instead.
5029 Re-write creates a difference in the state held by the client
5030 and server. Possibly causing confusion when the server response
5031 contains snippets of its view state. Embeded URLs, response
5032 and content Location headers, etc. are not re-written by this
5035 By default, a URL rewriter is not used.
5038 NAME: url_rewrite_children redirect_children
5039 TYPE: HelperChildConfig
5040 DEFAULT: 20 startup=0 idle=1 concurrency=0
5041 LOC: Config.redirectChildren
5043 The maximum number of redirector processes to spawn. If you limit
5044 it too few Squid will have to wait for them to process a backlog of
5045 URLs, slowing it down. If you allow too many they will use RAM
5046 and other system resources noticably.
5048 The startup= and idle= options allow some measure of skew in your
5053 Sets a minimum of how many processes are to be spawned when Squid
5054 starts or reconfigures. When set to zero the first request will
5055 cause spawning of the first child process to handle it.
5057 Starting too few will cause an initial slowdown in traffic as Squid
5058 attempts to simultaneously spawn enough processes to cope.
5062 Sets a minimum of how many processes Squid is to try and keep available
5063 at all times. When traffic begins to rise above what the existing
5064 processes can handle this many more will be spawned up to the maximum
5065 configured. A minimum setting of 1 is required.
5069 The number of requests each redirector helper can handle in
5070 parallel. Defaults to 0 which indicates the redirector
5071 is a old-style single threaded redirector.
5073 When this directive is set to a value >= 1 then the protocol
5074 used to communicate with the helper is modified to include
5075 an ID in front of the request/response. The ID from the request
5076 must be echoed back with the response to that request.
5080 Sets the maximum number of queued requests.
5081 If the queued requests exceed queue size and redirector_bypass
5082 configuration option is set, then redirector is bypassed. Otherwise, if
5083 overloading persists squid may abort its operation.
5084 The default value is set to 2*numberofchildren.
5087 NAME: url_rewrite_host_header redirect_rewrites_host_header
5090 LOC: Config.onoff.redir_rewrites_host
5092 To preserve same-origin security policies in browsers and
5093 prevent Host: header forgery by redirectors Squid rewrites
5094 any Host: header in redirected requests.
5096 If you are running an accelerator this may not be a wanted
5097 effect of a redirector. This directive enables you disable
5098 Host: alteration in reverse-proxy traffic.
5100 WARNING: Entries are cached on the result of the URL rewriting
5101 process, so be careful if you have domain-virtual hosts.
5103 WARNING: Squid and other software verifies the URL and Host
5104 are matching, so be careful not to relay through other proxies
5105 or inspecting firewalls with this disabled.
5108 NAME: url_rewrite_access redirector_access
5111 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
5112 LOC: Config.accessList.redirector
5114 If defined, this access list specifies which requests are
5115 sent to the redirector processes.
5117 This clause supports both fast and slow acl types.
5118 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5121 NAME: url_rewrite_bypass redirector_bypass
5123 LOC: Config.onoff.redirector_bypass
5126 When this is 'on', a request will not go through the
5127 redirector if all the helpers are busy. If this is 'off'
5128 and the redirector queue grows too large, Squid will exit
5129 with a FATAL error and ask you to increase the number of
5130 redirectors. You should only enable this if the redirectors
5131 are not critical to your caching system. If you use
5132 redirectors for access control, and you enable this option,
5133 users may have access to pages they should not
5134 be allowed to request.
5135 This options sets default queue-size option of the url_rewrite_children
5139 NAME: url_rewrite_extras
5140 TYPE: TokenOrQuotedString
5141 LOC: Config.redirector_extras
5142 DEFAULT: "%>a/%>A %un %>rm myip=%la myport=%lp"
5144 Specifies a string to be append to request line format for the
5145 rewriter helper. "Quoted" format values may contain spaces and
5146 logformat %macros. In theory, any logformat %macro can be used.
5147 In practice, a %macro expands as a dash (-) if the helper request is
5148 sent before the required macro information is available to Squid.
5151 NAME: url_rewrite_timeout
5152 TYPE: UrlHelperTimeout
5153 LOC: Config.onUrlRewriteTimeout
5155 DEFAULT_DOC: Squid waits for the helper response forever
5157 Squid times active requests to redirector. The timeout value and Squid
5158 reaction to a timed out request are configurable using the following
5161 url_rewrite_timeout timeout time-units on_timeout=<action> [response=<quoted-response>]
5163 supported timeout actions:
5164 fail Squid return a ERR_GATEWAY_FAILURE error page
5166 bypass Do not re-write the URL
5168 retry Send the lookup to the helper again
5170 use_configured_response
5171 Use the <quoted-response> as helper response
5175 OPTIONS FOR STORE ID
5176 -----------------------------------------------------------------------------
5179 NAME: store_id_program storeurl_rewrite_program
5181 LOC: Config.Program.store_id
5184 Specify the location of the executable StoreID helper to use.
5185 Since they can perform almost any function there isn't one included.
5187 For each requested URL, the helper will receive one line with the format
5189 [channel-ID <SP>] URL [<SP> extras]<NL>
5192 After processing the request the helper must reply using the following format:
5194 [channel-ID <SP>] result [<SP> kv-pairs]
5196 The result code can be:
5199 Use the StoreID supplied in 'store-id='.
5202 The default is to use HTTP request URL as the store ID.
5205 An internal error occured in the helper, preventing
5206 a result being identified.
5208 In addition to the above kv-pairs Squid also understands the following
5209 optional kv-pairs received from URL rewriters:
5211 Associates a TAG with the client TCP connection.
5212 Please see url_rewrite_program related documentation for this
5215 Helper programs should be prepared to receive and possibly ignore
5216 additional whitespace-separated tokens on each input line.
5218 When using the concurrency= option the protocol is changed by
5219 introducing a query channel tag in front of the request/response.
5220 The query channel tag is a number between 0 and concurrency-1.
5221 This value must be echoed back unchanged to Squid as the first part
5222 of the response relating to its request.
5224 NOTE: when using StoreID refresh_pattern will apply to the StoreID
5225 returned from the helper and not the URL.
5227 WARNING: Wrong StoreID value returned by a careless helper may result
5228 in the wrong cached response returned to the user.
5230 By default, a StoreID helper is not used.
5233 NAME: store_id_extras
5234 TYPE: TokenOrQuotedString
5235 LOC: Config.storeId_extras
5236 DEFAULT: "%>a/%>A %un %>rm myip=%la myport=%lp"
5238 Specifies a string to be append to request line format for the
5239 StoreId helper. "Quoted" format values may contain spaces and
5240 logformat %macros. In theory, any logformat %macro can be used.
5241 In practice, a %macro expands as a dash (-) if the helper request is
5242 sent before the required macro information is available to Squid.
5245 NAME: store_id_children storeurl_rewrite_children
5246 TYPE: HelperChildConfig
5247 DEFAULT: 20 startup=0 idle=1 concurrency=0
5248 LOC: Config.storeIdChildren
5250 The maximum number of StoreID helper processes to spawn. If you limit
5251 it too few Squid will have to wait for them to process a backlog of
5252 requests, slowing it down. If you allow too many they will use RAM
5253 and other system resources noticably.
5255 The startup= and idle= options allow some measure of skew in your
5260 Sets a minimum of how many processes are to be spawned when Squid
5261 starts or reconfigures. When set to zero the first request will
5262 cause spawning of the first child process to handle it.
5264 Starting too few will cause an initial slowdown in traffic as Squid
5265 attempts to simultaneously spawn enough processes to cope.
5269 Sets a minimum of how many processes Squid is to try and keep available
5270 at all times. When traffic begins to rise above what the existing
5271 processes can handle this many more will be spawned up to the maximum
5272 configured. A minimum setting of 1 is required.
5276 The number of requests each storeID helper can handle in
5277 parallel. Defaults to 0 which indicates the helper
5278 is a old-style single threaded program.
5280 When this directive is set to a value >= 1 then the protocol
5281 used to communicate with the helper is modified to include
5282 an ID in front of the request/response. The ID from the request
5283 must be echoed back with the response to that request.
5287 Sets the maximum number of queued requests.
5288 If the queued requests exceed queue size and store_id_bypass
5289 configuration option is set, then storeID helper is bypassed. Otherwise,
5290 if overloading persists squid may abort its operation.
5291 The default value is set to 2*numberofchildren.
5294 NAME: store_id_access storeurl_rewrite_access
5297 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
5298 LOC: Config.accessList.store_id
5300 If defined, this access list specifies which requests are
5301 sent to the StoreID processes. By default all requests
5304 This clause supports both fast and slow acl types.
5305 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5308 NAME: store_id_bypass storeurl_rewrite_bypass
5310 LOC: Config.onoff.store_id_bypass
5313 When this is 'on', a request will not go through the
5314 helper if all helpers are busy. If this is 'off'
5315 and the helper queue grows too large, Squid will exit
5316 with a FATAL error and ask you to increase the number of
5317 helpers. You should only enable this if the helperss
5318 are not critical to your caching system. If you use
5319 helpers for critical caching components, and you enable this
5320 option, users may not get objects from cache.
5321 This options sets default queue-size option of the store_id_children
5326 OPTIONS FOR TUNING THE CACHE
5327 -----------------------------------------------------------------------------
5330 NAME: cache no_cache
5333 DEFAULT_DOC: By default, this directive is unused and has no effect.
5334 LOC: Config.accessList.noCache
5336 Requests denied by this directive will not be served from the cache
5337 and their responses will not be stored in the cache. This directive
5338 has no effect on other transactions and on already cached responses.
5340 This clause supports both fast and slow acl types.
5341 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5343 This and the two other similar caching directives listed below are
5344 checked at different transaction processing stages, have different
5345 access to response information, affect different cache operations,
5346 and differ in slow ACLs support:
5348 * cache: Checked before Squid makes a hit/miss determination.
5349 No access to reply information!
5350 Denies both serving a hit and storing a miss.
5351 Supports both fast and slow ACLs.
5352 * send_hit: Checked after a hit was detected.
5353 Has access to reply (hit) information.
5354 Denies serving a hit only.
5355 Supports fast ACLs only.
5356 * store_miss: Checked before storing a cachable miss.
5357 Has access to reply (miss) information.
5358 Denies storing a miss only.
5359 Supports fast ACLs only.
5361 If you are not sure which of the three directives to use, apply the
5362 following decision logic:
5364 * If your ACL(s) are of slow type _and_ need response info, redesign.
5365 Squid does not support that particular combination at this time.
5367 * If your directive ACL(s) are of slow type, use "cache"; and/or
5368 * if your directive ACL(s) need no response info, use "cache".
5370 * If you do not want the response cached, use store_miss; and/or
5371 * if you do not want a hit on a cached response, use send_hit.
5377 DEFAULT_DOC: By default, this directive is unused and has no effect.
5378 LOC: Config.accessList.sendHit
5380 Responses denied by this directive will not be served from the cache
5381 (but may still be cached, see store_miss). This directive has no
5382 effect on the responses it allows and on the cached objects.
5384 Please see the "cache" directive for a summary of differences among
5385 store_miss, send_hit, and cache directives.
5387 Unlike the "cache" directive, send_hit only supports fast acl
5388 types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5392 # apply custom Store ID mapping to some URLs
5393 acl MapMe dstdomain .c.example.com
5394 store_id_program ...
5395 store_id_access allow MapMe
5397 # but prevent caching of special responses
5398 # such as 302 redirects that cause StoreID loops
5399 acl Ordinary http_status 200-299
5400 store_miss deny MapMe !Ordinary
5402 # and do not serve any previously stored special responses
5403 # from the cache (in case they were already cached before
5404 # the above store_miss rule was in effect).
5405 send_hit deny MapMe !Ordinary
5411 DEFAULT_DOC: By default, this directive is unused and has no effect.
5412 LOC: Config.accessList.storeMiss
5414 Responses denied by this directive will not be cached (but may still
5415 be served from the cache, see send_hit). This directive has no
5416 effect on the responses it allows and on the already cached responses.
5418 Please see the "cache" directive for a summary of differences among
5419 store_miss, send_hit, and cache directives. See the
5420 send_hit directive for a usage example.
5422 Unlike the "cache" directive, store_miss only supports fast acl
5423 types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5429 LOC: Config.maxStale
5432 This option puts an upper limit on how stale content Squid
5433 will serve from the cache if cache validation fails.
5434 Can be overriden by the refresh_pattern max-stale option.
5437 NAME: refresh_pattern
5438 TYPE: refreshpattern
5442 usage: refresh_pattern [-i] regex min percent max [options]
5444 By default, regular expressions are CASE-SENSITIVE. To make
5445 them case-insensitive, use the -i option.
5447 'Min' is the time (in minutes) an object without an explicit
5448 expiry time should be considered fresh. The recommended
5449 value is 0, any higher values may cause dynamic applications
5450 to be erroneously cached unless the application designer
5451 has taken the appropriate actions.
5453 'Percent' is a percentage of the objects age (time since last
5454 modification age) an object without explicit expiry time
5455 will be considered fresh.
5457 'Max' is an upper limit on how long objects without an explicit
5458 expiry time will be considered fresh.
5460 options: override-expire
5470 override-expire enforces min age even if the server
5471 sent an explicit expiry time (e.g., with the
5472 Expires: header or Cache-Control: max-age). Doing this
5473 VIOLATES the HTTP standard. Enabling this feature
5474 could make you liable for problems which it causes.
5476 Note: override-expire does not enforce staleness - it only extends
5477 freshness / min. If the server returns a Expires time which
5478 is longer than your max time, Squid will still consider
5479 the object fresh for that period of time.
5481 override-lastmod enforces min age even on objects
5482 that were modified recently.
5484 reload-into-ims changes a client no-cache or ``reload''
5485 request for a cached entry into a conditional request using
5486 If-Modified-Since and/or If-None-Match headers, provided the
5487 cached entry has a Last-Modified and/or a strong ETag header.
5488 Doing this VIOLATES the HTTP standard. Enabling this feature
5489 could make you liable for problems which it causes.
5491 ignore-reload ignores a client no-cache or ``reload''
5492 header. Doing this VIOLATES the HTTP standard. Enabling
5493 this feature could make you liable for problems which
5496 ignore-no-store ignores any ``Cache-control: no-store''
5497 headers received from a server. Doing this VIOLATES
5498 the HTTP standard. Enabling this feature could make you
5499 liable for problems which it causes.
5501 ignore-private ignores any ``Cache-control: private''
5502 headers received from a server. Doing this VIOLATES
5503 the HTTP standard. Enabling this feature could make you
5504 liable for problems which it causes.
5506 refresh-ims causes squid to contact the origin server
5507 when a client issues an If-Modified-Since request. This
5508 ensures that the client will receive an updated version
5509 if one is available.
5511 store-stale stores responses even if they don't have explicit
5512 freshness or a validator (i.e., Last-Modified or an ETag)
5513 present, or if they're already stale. By default, Squid will
5514 not cache such responses because they usually can't be
5515 reused. Note that such responses will be stale by default.
5517 max-stale=NN provide a maximum staleness factor. Squid won't
5518 serve objects more stale than this even if it failed to
5519 validate the object. Default: use the max_stale global limit.
5521 Basically a cached object is:
5523 FRESH if expires < now, else STALE
5525 FRESH if lm-factor < percent, else STALE
5529 The refresh_pattern lines are checked in the order listed here.
5530 The first entry which matches is used. If none of the entries
5531 match the default will be used.
5533 Note, you must uncomment all the default lines if you want
5534 to change one. The default setting is only active if none is
5540 # Add any of your own refresh_pattern entries above these.
5542 refresh_pattern ^ftp: 1440 20% 10080
5543 refresh_pattern ^gopher: 1440 0% 1440
5544 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0
5545 refresh_pattern . 0 20% 4320
5549 NAME: quick_abort_min
5553 LOC: Config.quickAbort.min
5556 NAME: quick_abort_max
5560 LOC: Config.quickAbort.max
5563 NAME: quick_abort_pct
5567 LOC: Config.quickAbort.pct
5569 The cache by default continues downloading aborted requests
5570 which are almost completed (less than 16 KB remaining). This
5571 may be undesirable on slow (e.g. SLIP) links and/or very busy
5572 caches. Impatient users may tie up file descriptors and
5573 bandwidth by repeatedly requesting and immediately aborting
5576 When the user aborts a request, Squid will check the
5577 quick_abort values to the amount of data transferred until
5580 If the transfer has less than 'quick_abort_min' KB remaining,
5581 it will finish the retrieval.
5583 If the transfer has more than 'quick_abort_max' KB remaining,
5584 it will abort the retrieval.
5586 If more than 'quick_abort_pct' of the transfer has completed,
5587 it will finish the retrieval.
5589 If you do not want any retrieval to continue after the client
5590 has aborted, set both 'quick_abort_min' and 'quick_abort_max'
5593 If you want retrievals to always continue if they are being
5594 cached set 'quick_abort_min' to '-1 KB'.
5597 NAME: read_ahead_gap
5598 COMMENT: buffer-size
5600 LOC: Config.readAheadGap
5603 The amount of data the cache will buffer ahead of what has been
5604 sent to the client when retrieving an object from another server.
5608 IFDEF: USE_HTTP_VIOLATIONS
5611 LOC: Config.negativeTtl
5614 Set the Default Time-to-Live (TTL) for failed requests.
5615 Certain types of failures (such as "connection refused" and
5616 "404 Not Found") are able to be negatively-cached for a short time.
5617 Modern web servers should provide Expires: header, however if they
5618 do not this can provide a minimum TTL.
5619 The default is not to cache errors with unknown expiry details.
5621 Note that this is different from negative caching of DNS lookups.
5623 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5624 this feature could make you liable for problems which it
5628 NAME: positive_dns_ttl
5631 LOC: Config.positiveDnsTtl
5634 Upper limit on how long Squid will cache positive DNS responses.
5635 Default is 6 hours (360 minutes). This directive must be set
5636 larger than negative_dns_ttl.
5639 NAME: negative_dns_ttl
5642 LOC: Config.negativeDnsTtl
5645 Time-to-Live (TTL) for negative caching of failed DNS lookups.
5646 This also sets the lower cache limit on positive lookups.
5647 Minimum value is 1 second, and it is not recommendable to go
5648 much below 10 seconds.
5651 NAME: range_offset_limit
5652 COMMENT: size [acl acl...]
5654 LOC: Config.rangeOffsetLimit
5657 usage: (size) [units] [[!]aclname]
5659 Sets an upper limit on how far (number of bytes) into the file
5660 a Range request may be to cause Squid to prefetch the whole file.
5661 If beyond this limit, Squid forwards the Range request as it is and
5662 the result is NOT cached.
5664 This is to stop a far ahead range request (lets say start at 17MB)
5665 from making Squid fetch the whole object up to that point before
5666 sending anything to the client.
5668 Multiple range_offset_limit lines may be specified, and they will
5669 be searched from top to bottom on each request until a match is found.
5670 The first match found will be used. If no line matches a request, the
5671 default limit of 0 bytes will be used.
5673 'size' is the limit specified as a number of units.
5675 'units' specifies whether to use bytes, KB, MB, etc.
5676 If no units are specified bytes are assumed.
5678 A size of 0 causes Squid to never fetch more than the
5679 client requested. (default)
5681 A size of 'none' causes Squid to always fetch the object from the
5682 beginning so it may cache the result. (2.0 style)
5684 'aclname' is the name of a defined ACL.
5686 NP: Using 'none' as the byte value here will override any quick_abort settings
5687 that may otherwise apply to the range request. The range request will
5688 be fully fetched from start to finish regardless of the client
5689 actions. This affects bandwidth usage.
5692 NAME: minimum_expiry_time
5695 LOC: Config.minimum_expiry_time
5698 The minimum caching time according to (Expires - Date)
5699 headers Squid honors if the object can't be revalidated.
5700 The default is 60 seconds.
5702 In reverse proxy environments it might be desirable to honor
5703 shorter object lifetimes. It is most likely better to make
5704 your server return a meaningful Last-Modified header however.
5706 In ESI environments where page fragments often have short
5707 lifetimes, this will often be best set to 0.
5710 NAME: store_avg_object_size
5714 LOC: Config.Store.avgObjectSize
5716 Average object size, used to estimate number of objects your
5717 cache can hold. The default is 13 KB.
5719 This is used to pre-seed the cache index memory allocation to
5720 reduce expensive reallocate operations while handling clients
5721 traffic. Too-large values may result in memory allocation during
5722 peak traffic, too-small values will result in wasted memory.
5724 Check the cache manager 'info' report metrics for the real
5725 object sizes seen by your Squid before tuning this.
5728 NAME: store_objects_per_bucket
5731 LOC: Config.Store.objectsPerBucket
5733 Target number of objects per bucket in the store hash table.
5734 Lowering this value increases the total number of buckets and
5735 also the storage maintenance rate. The default is 20.
5740 -----------------------------------------------------------------------------
5743 NAME: request_header_max_size
5747 LOC: Config.maxRequestHeaderSize
5749 This specifies the maximum size for HTTP headers in a request.
5750 Request headers are usually relatively small (about 512 bytes).
5751 Placing a limit on the request header size will catch certain
5752 bugs (for example with persistent connections) and possibly
5753 buffer-overflow or denial-of-service attacks.
5756 NAME: reply_header_max_size
5760 LOC: Config.maxReplyHeaderSize
5762 This specifies the maximum size for HTTP headers in a reply.
5763 Reply headers are usually relatively small (about 512 bytes).
5764 Placing a limit on the reply header size will catch certain
5765 bugs (for example with persistent connections) and possibly
5766 buffer-overflow or denial-of-service attacks.
5769 NAME: request_body_max_size
5773 DEFAULT_DOC: No limit.
5774 LOC: Config.maxRequestBodySize
5776 This specifies the maximum size for an HTTP request body.
5777 In other words, the maximum size of a PUT/POST request.
5778 A user who attempts to send a request with a body larger
5779 than this limit receives an "Invalid Request" error message.
5780 If you set this parameter to a zero (the default), there will
5781 be no limit imposed.
5783 See also client_request_buffer_max_size for an alternative
5784 limitation on client uploads which can be configured.
5787 NAME: client_request_buffer_max_size
5791 LOC: Config.maxRequestBufferSize
5793 This specifies the maximum buffer size of a client request.
5794 It prevents squid eating too much memory when somebody uploads
5799 IFDEF: USE_HTTP_VIOLATIONS
5802 DEFAULT_DOC: Obey RFC 2616.
5803 LOC: Config.accessList.brokenPosts
5805 A list of ACL elements which, if matched, causes Squid to send
5806 an extra CRLF pair after the body of a PUT/POST request.
5808 Some HTTP servers has broken implementations of PUT/POST,
5809 and rely on an extra CRLF pair sent by some WWW clients.
5811 Quote from RFC2616 section 4.1 on this matter:
5813 Note: certain buggy HTTP/1.0 client implementations generate an
5814 extra CRLF's after a POST request. To restate what is explicitly
5815 forbidden by the BNF, an HTTP/1.1 client must not preface or follow
5816 a request with an extra CRLF.
5818 This clause only supports fast acl types.
5819 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5822 acl buggy_server url_regex ^http://....
5823 broken_posts allow buggy_server
5826 NAME: adaptation_uses_indirect_client icap_uses_indirect_client
5829 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_ADAPTATION
5831 LOC: Adaptation::Config::use_indirect_client
5833 Controls whether the indirect client IP address (instead of the direct
5834 client IP address) is passed to adaptation services.
5836 See also: follow_x_forwarded_for adaptation_send_client_ip
5840 IFDEF: USE_HTTP_VIOLATIONS
5844 LOC: Config.onoff.via
5846 If set (default), Squid will include a Via header in requests and
5847 replies as required by RFC2616.
5853 LOC: Config.onoff.ie_refresh
5856 Microsoft Internet Explorer up until version 5.5 Service
5857 Pack 1 has an issue with transparent proxies, wherein it
5858 is impossible to force a refresh. Turning this on provides
5859 a partial fix to the problem, by causing all IMS-REFRESH
5860 requests from older IE versions to check the origin server
5861 for fresh content. This reduces hit ratio by some amount
5862 (~10% in my experience), but allows users to actually get
5863 fresh content when they want it. Note because Squid
5864 cannot tell if the user is using 5.5 or 5.5SP1, the behavior
5865 of 5.5 is unchanged from old versions of Squid (i.e. a
5866 forced refresh is impossible). Newer versions of IE will,
5867 hopefully, continue to have the new behavior and will be
5868 handled based on that assumption. This option defaults to
5869 the old Squid behavior, which is better for hit ratios but
5870 worse for clients using IE, if they need to be able to
5871 force fresh content.
5874 NAME: vary_ignore_expire
5877 LOC: Config.onoff.vary_ignore_expire
5880 Many HTTP servers supporting Vary gives such objects
5881 immediate expiry time with no cache-control header
5882 when requested by a HTTP/1.0 client. This option
5883 enables Squid to ignore such expiry times until
5884 HTTP/1.1 is fully implemented.
5886 WARNING: If turned on this may eventually cause some
5887 varying objects not intended for caching to get cached.
5890 NAME: request_entities
5892 LOC: Config.onoff.request_entities
5895 Squid defaults to deny GET and HEAD requests with request entities,
5896 as the meaning of such requests are undefined in the HTTP standard
5897 even if not explicitly forbidden.
5899 Set this directive to on if you have clients which insists
5900 on sending request entities in GET or HEAD requests. But be warned
5901 that there is server software (both proxies and web servers) which
5902 can fail to properly process this kind of request which may make you
5903 vulnerable to cache pollution attacks if enabled.
5906 NAME: request_header_access
5907 IFDEF: USE_HTTP_VIOLATIONS
5908 TYPE: http_header_access
5909 LOC: Config.request_header_access
5911 DEFAULT_DOC: No limits.
5913 Usage: request_header_access header_name allow|deny [!]aclname ...
5915 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5916 this feature could make you liable for problems which it
5919 This option replaces the old 'anonymize_headers' and the
5920 older 'http_anonymizer' option with something that is much
5921 more configurable. A list of ACLs for each header name allows
5922 removal of specific header fields under specific conditions.
5924 This option only applies to outgoing HTTP request headers (i.e.,
5925 headers sent by Squid to the next HTTP hop such as a cache peer
5926 or an origin server). The option has no effect during cache hit
5927 detection. The equivalent adaptation vectoring point in ICAP
5928 terminology is post-cache REQMOD.
5930 The option is applied to individual outgoing request header
5931 fields. For each request header field F, Squid uses the first
5932 qualifying sets of request_header_access rules:
5934 1. Rules with header_name equal to F's name.
5935 2. Rules with header_name 'Other', provided F's name is not
5936 on the hard-coded list of commonly used HTTP header names.
5937 3. Rules with header_name 'All'.
5939 Within that qualifying rule set, rule ACLs are checked as usual.
5940 If ACLs of an "allow" rule match, the header field is allowed to
5941 go through as is. If ACLs of a "deny" rule match, the header is
5942 removed and request_header_replace is then checked to identify
5943 if the removed header has a replacement. If no rules within the
5944 set have matching ACLs, the header field is left as is.
5946 For example, to achieve the same behavior as the old
5947 'http_anonymizer standard' option, you should use:
5949 request_header_access From deny all
5950 request_header_access Referer deny all
5951 request_header_access User-Agent deny all
5953 Or, to reproduce the old 'http_anonymizer paranoid' feature
5956 request_header_access Authorization allow all
5957 request_header_access Proxy-Authorization allow all
5958 request_header_access Cache-Control allow all
5959 request_header_access Content-Length allow all
5960 request_header_access Content-Type allow all
5961 request_header_access Date allow all
5962 request_header_access Host allow all
5963 request_header_access If-Modified-Since allow all
5964 request_header_access Pragma allow all
5965 request_header_access Accept allow all
5966 request_header_access Accept-Charset allow all
5967 request_header_access Accept-Encoding allow all
5968 request_header_access Accept-Language allow all
5969 request_header_access Connection allow all
5970 request_header_access All deny all
5972 HTTP reply headers are controlled with the reply_header_access directive.
5974 By default, all headers are allowed (no anonymizing is performed).
5977 NAME: reply_header_access
5978 IFDEF: USE_HTTP_VIOLATIONS
5979 TYPE: http_header_access
5980 LOC: Config.reply_header_access
5982 DEFAULT_DOC: No limits.
5984 Usage: reply_header_access header_name allow|deny [!]aclname ...
5986 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5987 this feature could make you liable for problems which it
5990 This option only applies to reply headers, i.e., from the
5991 server to the client.
5993 This is the same as request_header_access, but in the other
5994 direction. Please see request_header_access for detailed
5997 For example, to achieve the same behavior as the old
5998 'http_anonymizer standard' option, you should use:
6000 reply_header_access Server deny all
6001 reply_header_access WWW-Authenticate deny all
6002 reply_header_access Link deny all
6004 Or, to reproduce the old 'http_anonymizer paranoid' feature
6007 reply_header_access Allow allow all
6008 reply_header_access WWW-Authenticate allow all
6009 reply_header_access Proxy-Authenticate allow all
6010 reply_header_access Cache-Control allow all
6011 reply_header_access Content-Encoding allow all
6012 reply_header_access Content-Length allow all
6013 reply_header_access Content-Type allow all
6014 reply_header_access Date allow all
6015 reply_header_access Expires allow all
6016 reply_header_access Last-Modified allow all
6017 reply_header_access Location allow all
6018 reply_header_access Pragma allow all
6019 reply_header_access Content-Language allow all
6020 reply_header_access Retry-After allow all
6021 reply_header_access Title allow all
6022 reply_header_access Content-Disposition allow all
6023 reply_header_access Connection allow all
6024 reply_header_access All deny all
6026 HTTP request headers are controlled with the request_header_access directive.
6028 By default, all headers are allowed (no anonymizing is
6032 NAME: request_header_replace header_replace
6033 IFDEF: USE_HTTP_VIOLATIONS
6034 TYPE: http_header_replace
6035 LOC: Config.request_header_access
6038 Usage: request_header_replace header_name message
6039 Example: request_header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
6041 This option allows you to change the contents of headers
6042 denied with request_header_access above, by replacing them
6043 with some fixed string.
6045 This only applies to request headers, not reply headers.
6047 By default, headers are removed if denied.
6050 NAME: reply_header_replace
6051 IFDEF: USE_HTTP_VIOLATIONS
6052 TYPE: http_header_replace
6053 LOC: Config.reply_header_access
6056 Usage: reply_header_replace header_name message
6057 Example: reply_header_replace Server Foo/1.0
6059 This option allows you to change the contents of headers
6060 denied with reply_header_access above, by replacing them
6061 with some fixed string.
6063 This only applies to reply headers, not request headers.
6065 By default, headers are removed if denied.
6068 NAME: request_header_add
6069 TYPE: HeaderWithAclList
6070 LOC: Config.request_header_add
6073 Usage: request_header_add field-name field-value acl1 [acl2] ...
6074 Example: request_header_add X-Client-CA "CA=%ssl::>cert_issuer" all
6076 This option adds header fields to outgoing HTTP requests (i.e.,
6077 request headers sent by Squid to the next HTTP hop such as a
6078 cache peer or an origin server). The option has no effect during
6079 cache hit detection. The equivalent adaptation vectoring point
6080 in ICAP terminology is post-cache REQMOD.
6082 Field-name is a token specifying an HTTP header name. If a
6083 standard HTTP header name is used, Squid does not check whether
6084 the new header conflicts with any existing headers or violates
6085 HTTP rules. If the request to be modified already contains a
6086 field with the same name, the old field is preserved but the
6087 header field values are not merged.
6089 Field-value is either a token or a quoted string. If quoted
6090 string format is used, then the surrounding quotes are removed
6091 while escape sequences and %macros are processed.
6093 In theory, all of the logformat codes can be used as %macros.
6094 However, unlike logging (which happens at the very end of
6095 transaction lifetime), the transaction may not yet have enough
6096 information to expand a macro when the new header value is needed.
6097 And some information may already be available to Squid but not yet
6098 committed where the macro expansion code can access it (report
6099 such instances!). The macro will be expanded into a single dash
6100 ('-') in such cases. Not all macros have been tested.
6102 One or more Squid ACLs may be specified to restrict header
6103 injection to matching requests. As always in squid.conf, all
6104 ACLs in an option ACL list must be satisfied for the insertion
6105 to happen. The request_header_add option supports fast ACLs
6114 This option used to log custom information about the master
6115 transaction. For example, an admin may configure Squid to log
6116 which "user group" the transaction belongs to, where "user group"
6117 will be determined based on a set of ACLs and not [just]
6118 authentication information.
6119 Values of key/value pairs can be logged using %{key}note macros:
6121 note key value acl ...
6122 logformat myFormat ... %{key}note ...
6125 NAME: relaxed_header_parser
6126 COMMENT: on|off|warn
6128 LOC: Config.onoff.relaxed_header_parser
6131 In the default "on" setting Squid accepts certain forms
6132 of non-compliant HTTP messages where it is unambiguous
6133 what the sending application intended even if the message
6134 is not correctly formatted. The messages is then normalized
6135 to the correct form when forwarded by Squid.
6137 If set to "warn" then a warning will be emitted in cache.log
6138 each time such HTTP error is encountered.
6140 If set to "off" then such HTTP errors will cause the request
6141 or response to be rejected.
6144 NAME: collapsed_forwarding
6147 LOC: Config.onoff.collapsed_forwarding
6150 This option controls whether Squid is allowed to merge multiple
6151 potentially cachable requests for the same URI before Squid knows
6152 whether the response is going to be cachable.
6154 This feature is disabled by default: Enabling collapsed forwarding
6155 needlessly delays forwarding requests that look cachable (when they are
6156 collapsed) but then need to be forwarded individually anyway because
6157 they end up being for uncachable content. However, in some cases, such
6158 as accelleration of highly cachable content with periodic or groupped
6159 expiration times, the gains from collapsing [large volumes of
6160 simultenous refresh requests] outweigh losses from such delays.
6165 -----------------------------------------------------------------------------
6168 NAME: forward_timeout
6171 LOC: Config.Timeout.forward
6174 This parameter specifies how long Squid should at most attempt in
6175 finding a forwarding path for the request before giving up.
6178 NAME: connect_timeout
6181 LOC: Config.Timeout.connect
6184 This parameter specifies how long to wait for the TCP connect to
6185 the requested server or peer to complete before Squid should
6186 attempt to find another path where to forward the request.
6189 NAME: peer_connect_timeout
6192 LOC: Config.Timeout.peer_connect
6195 This parameter specifies how long to wait for a pending TCP
6196 connection to a peer cache. The default is 30 seconds. You
6197 may also set different timeout values for individual neighbors
6198 with the 'connect-timeout' option on a 'cache_peer' line.
6204 LOC: Config.Timeout.read
6207 Applied on peer server connections.
6209 After each successful read(), the timeout will be extended by this
6210 amount. If no data is read again after this amount of time,
6211 the request is aborted and logged with ERR_READ_TIMEOUT.
6213 The default is 15 minutes.
6219 LOC: Config.Timeout.write
6222 This timeout is tracked for all connections that have data
6223 available for writing and are waiting for the socket to become
6224 ready. After each successful write, the timeout is extended by
6225 the configured amount. If Squid has data to write but the
6226 connection is not ready for the configured duration, the
6227 transaction associated with the connection is terminated. The
6228 default is 15 minutes.
6231 NAME: request_timeout
6233 LOC: Config.Timeout.request
6236 How long to wait for complete HTTP request headers after initial
6237 connection establishment.
6240 NAME: request_start_timeout
6242 LOC: Config.Timeout.request_start_timeout
6245 How long to wait for the first request byte after initial
6246 connection establishment.
6249 NAME: client_idle_pconn_timeout persistent_request_timeout
6251 LOC: Config.Timeout.clientIdlePconn
6254 How long to wait for the next HTTP request on a persistent
6255 client connection after the previous request completes.
6258 NAME: ftp_client_idle_timeout
6260 LOC: Config.Timeout.ftpClientIdle
6263 How long to wait for an FTP request on a connection to Squid ftp_port.
6264 Many FTP clients do not deal with idle connection closures well,
6265 necessitating a longer default timeout than client_idle_pconn_timeout
6266 used for incoming HTTP requests.
6269 NAME: client_lifetime
6272 LOC: Config.Timeout.lifetime
6275 The maximum amount of time a client (browser) is allowed to
6276 remain connected to the cache process. This protects the Cache
6277 from having a lot of sockets (and hence file descriptors) tied up
6278 in a CLOSE_WAIT state from remote clients that go away without
6279 properly shutting down (either because of a network failure or
6280 because of a poor client implementation). The default is one
6283 NOTE: The default value is intended to be much larger than any
6284 client would ever need to be connected to your cache. You
6285 should probably change client_lifetime only as a last resort.
6286 If you seem to have many client connections tying up
6287 filedescriptors, we recommend first tuning the read_timeout,
6288 request_timeout, persistent_request_timeout and quick_abort values.
6291 NAME: pconn_lifetime
6294 LOC: Config.Timeout.pconnLifetime
6297 Desired maximum lifetime of a persistent connection.
6298 When set, Squid will close a now-idle persistent connection that
6299 exceeded configured lifetime instead of moving the connection into
6300 the idle connection pool (or equivalent). No effect on ongoing/active
6301 transactions. Connection lifetime is the time period from the
6302 connection acceptance or opening time until "now".
6304 This limit is useful in environments with long-lived connections
6305 where Squid configuration or environmental factors change during a
6306 single connection lifetime. If unrestricted, some connections may
6307 last for hours and even days, ignoring those changes that should
6308 have affected their behavior or their existence.
6310 Currently, a new lifetime value supplied via Squid reconfiguration
6311 has no effect on already idle connections unless they become busy.
6313 When set to '0' this limit is not used.
6316 NAME: half_closed_clients
6318 LOC: Config.onoff.half_closed_clients
6321 Some clients may shutdown the sending side of their TCP
6322 connections, while leaving their receiving sides open. Sometimes,
6323 Squid can not tell the difference between a half-closed and a
6324 fully-closed TCP connection.
6326 By default, Squid will immediately close client connections when
6327 read(2) returns "no more data to read."
6329 Change this option to 'on' and Squid will keep open connections
6330 until a read(2) or write(2) on the socket returns an error.
6331 This may show some benefits for reverse proxies. But if not
6332 it is recommended to leave OFF.
6335 NAME: server_idle_pconn_timeout pconn_timeout
6337 LOC: Config.Timeout.serverIdlePconn
6340 Timeout for idle persistent connections to servers and other
6347 LOC: Ident::TheConfig.timeout
6350 Maximum time to wait for IDENT lookups to complete.
6352 If this is too high, and you enabled IDENT lookups from untrusted
6353 users, you might be susceptible to denial-of-service by having
6354 many ident requests going at once.
6357 NAME: shutdown_lifetime
6360 LOC: Config.shutdownLifetime
6363 When SIGTERM or SIGHUP is received, the cache is put into
6364 "shutdown pending" mode until all active sockets are closed.
6365 This value is the lifetime to set for all open descriptors
6366 during shutdown mode. Any active clients after this many
6367 seconds will receive a 'timeout' message.
6371 ADMINISTRATIVE PARAMETERS
6372 -----------------------------------------------------------------------------
6378 LOC: Config.adminEmail
6380 Email-address of local cache manager who will receive
6381 mail if the cache dies. The default is "webmaster".
6387 LOC: Config.EmailFrom
6389 From: email-address for mail sent when the cache dies.
6390 The default is to use 'squid@unique_hostname'.
6392 See also: unique_hostname directive.
6398 LOC: Config.EmailProgram
6400 Email program used to send mail if the cache dies.
6401 The default is "mail". The specified program must comply
6402 with the standard Unix mail syntax:
6403 mail-program recipient < mailfile
6405 Optional command line options can be specified.
6408 NAME: cache_effective_user
6410 DEFAULT: @DEFAULT_CACHE_EFFECTIVE_USER@
6411 LOC: Config.effectiveUser
6413 If you start Squid as root, it will change its effective/real
6414 UID/GID to the user specified below. The default is to change
6415 to UID of @DEFAULT_CACHE_EFFECTIVE_USER@.
6416 see also; cache_effective_group
6419 NAME: cache_effective_group
6422 DEFAULT_DOC: Use system group memberships of the cache_effective_user account
6423 LOC: Config.effectiveGroup
6425 Squid sets the GID to the effective user's default group ID
6426 (taken from the password file) and supplementary group list
6427 from the groups membership.
6429 If you want Squid to run with a specific GID regardless of
6430 the group memberships of the effective user then set this
6431 to the group (or GID) you want Squid to run as. When set
6432 all other group privileges of the effective user are ignored
6433 and only this GID is effective. If Squid is not started as
6434 root the user starting Squid MUST be member of the specified
6437 This option is not recommended by the Squid Team.
6438 Our preference is for administrators to configure a secure
6439 user account for squid with UID/GID matching system policies.
6442 NAME: httpd_suppress_version_string
6446 LOC: Config.onoff.httpd_suppress_version_string
6448 Suppress Squid version string info in HTTP headers and HTML error pages.
6451 NAME: visible_hostname
6453 LOC: Config.visibleHostname
6455 DEFAULT_DOC: Automatically detect the system host name
6457 If you want to present a special hostname in error messages, etc,
6458 define this. Otherwise, the return value of gethostname()
6459 will be used. If you have multiple caches in a cluster and
6460 get errors about IP-forwarding you must set them to have individual
6461 names with this setting.
6464 NAME: unique_hostname
6466 LOC: Config.uniqueHostname
6468 DEFAULT_DOC: Copy the value from visible_hostname
6470 If you want to have multiple machines with the same
6471 'visible_hostname' you must give each machine a different
6472 'unique_hostname' so forwarding loops can be detected.
6475 NAME: hostname_aliases
6477 LOC: Config.hostnameAliases
6480 A list of other DNS names your cache has.
6488 Minimum umask which should be enforced while the proxy
6489 is running, in addition to the umask set at startup.
6491 For a traditional octal representation of umasks, start
6496 OPTIONS FOR THE CACHE REGISTRATION SERVICE
6497 -----------------------------------------------------------------------------
6499 This section contains parameters for the (optional) cache
6500 announcement service. This service is provided to help
6501 cache administrators locate one another in order to join or
6502 create cache hierarchies.
6504 An 'announcement' message is sent (via UDP) to the registration
6505 service by Squid. By default, the announcement message is NOT
6506 SENT unless you enable it with 'announce_period' below.
6508 The announcement message includes your hostname, plus the
6509 following information from this configuration file:
6515 All current information is processed regularly and made
6516 available on the Web at http://www.ircache.net/Cache/Tracker/.
6519 NAME: announce_period
6521 LOC: Config.Announce.period
6523 DEFAULT_DOC: Announcement messages disabled.
6525 This is how frequently to send cache announcements.
6527 To enable announcing your cache, just set an announce period.
6530 announce_period 1 day
6535 DEFAULT: tracker.ircache.net
6536 LOC: Config.Announce.host
6538 Set the hostname where announce registration messages will be sent.
6540 See also announce_port and announce_file
6546 LOC: Config.Announce.file
6548 The contents of this file will be included in the announce
6549 registration messages.
6555 LOC: Config.Announce.port
6557 Set the port where announce registration messages will be sent.
6559 See also announce_host and announce_file
6563 HTTPD-ACCELERATOR OPTIONS
6564 -----------------------------------------------------------------------------
6567 NAME: httpd_accel_surrogate_id
6570 DEFAULT_DOC: visible_hostname is used if no specific ID is set.
6571 LOC: Config.Accel.surrogate_id
6573 Surrogates (http://www.esi.org/architecture_spec_1.0.html)
6574 need an identification token to allow control targeting. Because
6575 a farm of surrogates may all perform the same tasks, they may share
6576 an identification token.
6579 NAME: http_accel_surrogate_remote
6583 LOC: Config.onoff.surrogate_is_remote
6585 Remote surrogates (such as those in a CDN) honour the header
6586 "Surrogate-Control: no-store-remote".
6588 Set this to on to have squid behave as a remote surrogate.
6592 IFDEF: USE_SQUID_ESI
6593 COMMENT: libxml2|expat|custom
6595 LOC: ESIParser::Type
6598 ESI markup is not strictly XML compatible. The custom ESI parser
6599 will give higher performance, but cannot handle non ASCII character
6604 DELAY POOL PARAMETERS
6605 -----------------------------------------------------------------------------
6609 TYPE: delay_pool_count
6611 IFDEF: USE_DELAY_POOLS
6614 This represents the number of delay pools to be used. For example,
6615 if you have one class 2 delay pool and one class 3 delays pool, you
6616 have a total of 2 delay pools.
6618 See also delay_parameters, delay_class, delay_access for pool
6619 configuration details.
6623 TYPE: delay_pool_class
6625 IFDEF: USE_DELAY_POOLS
6628 This defines the class of each delay pool. There must be exactly one
6629 delay_class line for each delay pool. For example, to define two
6630 delay pools, one of class 2 and one of class 3, the settings above
6634 delay_pools 4 # 4 delay pools
6635 delay_class 1 2 # pool 1 is a class 2 pool
6636 delay_class 2 3 # pool 2 is a class 3 pool
6637 delay_class 3 4 # pool 3 is a class 4 pool
6638 delay_class 4 5 # pool 4 is a class 5 pool
6640 The delay pool classes are:
6642 class 1 Everything is limited by a single aggregate
6645 class 2 Everything is limited by a single aggregate
6646 bucket as well as an "individual" bucket chosen
6647 from bits 25 through 32 of the IPv4 address.
6649 class 3 Everything is limited by a single aggregate
6650 bucket as well as a "network" bucket chosen
6651 from bits 17 through 24 of the IP address and a
6652 "individual" bucket chosen from bits 17 through
6653 32 of the IPv4 address.
6655 class 4 Everything in a class 3 delay pool, with an
6656 additional limit on a per user basis. This
6657 only takes effect if the username is established
6658 in advance - by forcing authentication in your
6661 class 5 Requests are grouped according their tag (see
6662 external_acl's tag= reply).
6665 Each pool also requires a delay_parameters directive to configure the pool size
6666 and speed limits used whenever the pool is applied to a request. Along with
6667 a set of delay_access directives to determine when it is used.
6669 NOTE: If an IP address is a.b.c.d
6670 -> bits 25 through 32 are "d"
6671 -> bits 17 through 24 are "c"
6672 -> bits 17 through 32 are "c * 256 + d"
6674 NOTE-2: Due to the use of bitmasks in class 2,3,4 pools they only apply to
6675 IPv4 traffic. Class 1 and 5 pools may be used with IPv6 traffic.
6677 This clause only supports fast acl types.
6678 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6680 See also delay_parameters and delay_access.
6684 TYPE: delay_pool_access
6686 DEFAULT_DOC: Deny using the pool, unless allow rules exist in squid.conf for the pool.
6687 IFDEF: USE_DELAY_POOLS
6690 This is used to determine which delay pool a request falls into.
6692 delay_access is sorted per pool and the matching starts with pool 1,
6693 then pool 2, ..., and finally pool N. The first delay pool where the
6694 request is allowed is selected for the request. If it does not allow
6695 the request to any pool then the request is not delayed (default).
6697 For example, if you want some_big_clients in delay
6698 pool 1 and lotsa_little_clients in delay pool 2:
6700 delay_access 1 allow some_big_clients
6701 delay_access 1 deny all
6702 delay_access 2 allow lotsa_little_clients
6703 delay_access 2 deny all
6704 delay_access 3 allow authenticated_clients
6706 See also delay_parameters and delay_class.
6710 NAME: delay_parameters
6711 TYPE: delay_pool_rates
6713 IFDEF: USE_DELAY_POOLS
6716 This defines the parameters for a delay pool. Each delay pool has
6717 a number of "buckets" associated with it, as explained in the
6718 description of delay_class.
6720 For a class 1 delay pool, the syntax is:
6722 delay_parameters pool aggregate
6724 For a class 2 delay pool:
6726 delay_parameters pool aggregate individual
6728 For a class 3 delay pool:
6730 delay_parameters pool aggregate network individual
6732 For a class 4 delay pool:
6734 delay_parameters pool aggregate network individual user
6736 For a class 5 delay pool:
6738 delay_parameters pool tagrate
6740 The option variables are:
6742 pool a pool number - ie, a number between 1 and the
6743 number specified in delay_pools as used in
6746 aggregate the speed limit parameters for the aggregate bucket
6749 individual the speed limit parameters for the individual
6750 buckets (class 2, 3).
6752 network the speed limit parameters for the network buckets
6755 user the speed limit parameters for the user buckets
6758 tagrate the speed limit parameters for the tag buckets
6761 A pair of delay parameters is written restore/maximum, where restore is
6762 the number of bytes (not bits - modem and network speeds are usually
6763 quoted in bits) per second placed into the bucket, and maximum is the
6764 maximum number of bytes which can be in the bucket at any time.
6766 There must be one delay_parameters line for each delay pool.
6769 For example, if delay pool number 1 is a class 2 delay pool as in the
6770 above example, and is being used to strictly limit each host to 64Kbit/sec
6771 (plus overheads), with no overall limit, the line is:
6773 delay_parameters 1 none 8000/8000
6775 Note that 8 x 8000 KByte/sec -> 64Kbit/sec.
6777 Note that the word 'none' is used to represent no limit.
6780 And, if delay pool number 2 is a class 3 delay pool as in the above
6781 example, and you want to limit it to a total of 256Kbit/sec (strict limit)
6782 with each 8-bit network permitted 64Kbit/sec (strict limit) and each
6783 individual host permitted 4800bit/sec with a bucket maximum size of 64Kbits
6784 to permit a decent web page to be downloaded at a decent speed
6785 (if the network is not being limited due to overuse) but slow down
6786 large downloads more significantly:
6788 delay_parameters 2 32000/32000 8000/8000 600/8000
6790 Note that 8 x 32000 KByte/sec -> 256Kbit/sec.
6791 8 x 8000 KByte/sec -> 64Kbit/sec.
6792 8 x 600 Byte/sec -> 4800bit/sec.
6795 Finally, for a class 4 delay pool as in the example - each user will
6796 be limited to 128Kbits/sec no matter how many workstations they are logged into.:
6798 delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000
6801 See also delay_class and delay_access.
6805 NAME: delay_initial_bucket_level
6806 COMMENT: (percent, 0-100)
6809 IFDEF: USE_DELAY_POOLS
6810 LOC: Config.Delay.initial
6812 The initial bucket percentage is used to determine how much is put
6813 in each bucket when squid starts, is reconfigured, or first notices
6814 a host accessing it (in class 2 and class 3, individual hosts and
6815 networks only have buckets associated with them once they have been
6820 CLIENT DELAY POOL PARAMETERS
6821 -----------------------------------------------------------------------------
6824 NAME: client_delay_pools
6825 TYPE: client_delay_pool_count
6827 IFDEF: USE_DELAY_POOLS
6828 LOC: Config.ClientDelay
6830 This option specifies the number of client delay pools used. It must
6831 preceed other client_delay_* options.
6834 client_delay_pools 2
6836 See also client_delay_parameters and client_delay_access.
6839 NAME: client_delay_initial_bucket_level
6840 COMMENT: (percent, 0-no_limit)
6843 IFDEF: USE_DELAY_POOLS
6844 LOC: Config.ClientDelay.initial
6846 This option determines the initial bucket size as a percentage of
6847 max_bucket_size from client_delay_parameters. Buckets are created
6848 at the time of the "first" connection from the matching IP. Idle
6849 buckets are periodically deleted up.
6851 You can specify more than 100 percent but note that such "oversized"
6852 buckets are not refilled until their size goes down to max_bucket_size
6853 from client_delay_parameters.
6856 client_delay_initial_bucket_level 50
6859 NAME: client_delay_parameters
6860 TYPE: client_delay_pool_rates
6862 IFDEF: USE_DELAY_POOLS
6863 LOC: Config.ClientDelay
6866 This option configures client-side bandwidth limits using the
6869 client_delay_parameters pool speed_limit max_bucket_size
6871 pool is an integer ID used for client_delay_access matching.
6873 speed_limit is bytes added to the bucket per second.
6875 max_bucket_size is the maximum size of a bucket, enforced after any
6876 speed_limit additions.
6878 Please see the delay_parameters option for more information and
6882 client_delay_parameters 1 1024 2048
6883 client_delay_parameters 2 51200 16384
6885 See also client_delay_access.
6889 NAME: client_delay_access
6890 TYPE: client_delay_pool_access
6892 DEFAULT_DOC: Deny use of the pool, unless allow rules exist in squid.conf for the pool.
6893 IFDEF: USE_DELAY_POOLS
6894 LOC: Config.ClientDelay
6896 This option determines the client-side delay pool for the
6899 client_delay_access pool_ID allow|deny acl_name
6901 All client_delay_access options are checked in their pool ID
6902 order, starting with pool 1. The first checked pool with allowed
6903 request is selected for the request. If no ACL matches or there
6904 are no client_delay_access options, the request bandwidth is not
6907 The ACL-selected pool is then used to find the
6908 client_delay_parameters for the request. Client-side pools are
6909 not used to aggregate clients. Clients are always aggregated
6910 based on their source IP addresses (one bucket per source IP).
6912 This clause only supports fast acl types.
6913 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6914 Additionally, only the client TCP connection details are available.
6915 ACLs testing HTTP properties will not work.
6917 Please see delay_access for more examples.
6920 client_delay_access 1 allow low_rate_network
6921 client_delay_access 2 allow vips_network
6924 See also client_delay_parameters and client_delay_pools.
6928 WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS
6929 -----------------------------------------------------------------------------
6934 LOC: Config.Wccp.router
6936 DEFAULT_DOC: WCCP disabled.
6939 Use this option to define your WCCP ``home'' router for
6942 wccp_router supports a single WCCP(v1) router
6944 wccp2_router supports multiple WCCPv2 routers
6946 only one of the two may be used at the same time and defines
6947 which version of WCCP to use.
6951 TYPE: IpAddress_list
6952 LOC: Config.Wccp2.router
6954 DEFAULT_DOC: WCCPv2 disabled.
6957 Use this option to define your WCCP ``home'' router for
6960 wccp_router supports a single WCCP(v1) router
6962 wccp2_router supports multiple WCCPv2 routers
6964 only one of the two may be used at the same time and defines
6965 which version of WCCP to use.
6970 LOC: Config.Wccp.version
6974 This directive is only relevant if you need to set up WCCP(v1)
6975 to some very old and end-of-life Cisco routers. In all other
6976 setups it must be left unset or at the default setting.
6977 It defines an internal version in the WCCP(v1) protocol,
6978 with version 4 being the officially documented protocol.
6980 According to some users, Cisco IOS 11.2 and earlier only
6981 support WCCP version 3. If you're using that or an earlier
6982 version of IOS, you may need to change this value to 3, otherwise
6983 do not specify this parameter.
6986 NAME: wccp2_rebuild_wait
6988 LOC: Config.Wccp2.rebuildwait
6992 If this is enabled Squid will wait for the cache dir rebuild to finish
6993 before sending the first wccp2 HereIAm packet
6996 NAME: wccp2_forwarding_method
6998 LOC: Config.Wccp2.forwarding_method
7002 WCCP2 allows the setting of forwarding methods between the
7003 router/switch and the cache. Valid values are as follows:
7005 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
7006 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
7008 Currently (as of IOS 12.4) cisco routers only support GRE.
7009 Cisco switches only support the L2 redirect assignment method.
7012 NAME: wccp2_return_method
7014 LOC: Config.Wccp2.return_method
7018 WCCP2 allows the setting of return methods between the
7019 router/switch and the cache for packets that the cache
7020 decides not to handle. Valid values are as follows:
7022 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
7023 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
7025 Currently (as of IOS 12.4) cisco routers only support GRE.
7026 Cisco switches only support the L2 redirect assignment.
7028 If the "ip wccp redirect exclude in" command has been
7029 enabled on the cache interface, then it is still safe for
7030 the proxy server to use a l2 redirect method even if this
7031 option is set to GRE.
7034 NAME: wccp2_assignment_method
7036 LOC: Config.Wccp2.assignment_method
7040 WCCP2 allows the setting of methods to assign the WCCP hash
7041 Valid values are as follows:
7043 hash - Hash assignment
7044 mask - Mask assignment
7046 As a general rule, cisco routers support the hash assignment method
7047 and cisco switches support the mask assignment method.
7052 LOC: Config.Wccp2.info
7053 DEFAULT_IF_NONE: standard 0
7054 DEFAULT_DOC: Use the 'web-cache' standard service.
7057 WCCP2 allows for multiple traffic services. There are two
7058 types: "standard" and "dynamic". The standard type defines
7059 one service id - http (id 0). The dynamic service ids can be from
7060 51 to 255 inclusive. In order to use a dynamic service id
7061 one must define the type of traffic to be redirected; this is done
7062 using the wccp2_service_info option.
7064 The "standard" type does not require a wccp2_service_info option,
7065 just specifying the service id will suffice.
7067 MD5 service authentication can be enabled by adding
7068 "password=<password>" to the end of this service declaration.
7072 wccp2_service standard 0 # for the 'web-cache' standard service
7073 wccp2_service dynamic 80 # a dynamic service type which will be
7074 # fleshed out with subsequent options.
7075 wccp2_service standard 0 password=foo
7078 NAME: wccp2_service_info
7079 TYPE: wccp2_service_info
7080 LOC: Config.Wccp2.info
7084 Dynamic WCCPv2 services require further information to define the
7085 traffic you wish to have diverted.
7089 wccp2_service_info <id> protocol=<protocol> flags=<flag>,<flag>..
7090 priority=<priority> ports=<port>,<port>..
7092 The relevant WCCPv2 flags:
7093 + src_ip_hash, dst_ip_hash
7094 + source_port_hash, dst_port_hash
7095 + src_ip_alt_hash, dst_ip_alt_hash
7096 + src_port_alt_hash, dst_port_alt_hash
7099 The port list can be one to eight entries.
7103 wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source
7104 priority=240 ports=80
7106 Note: the service id must have been defined by a previous
7107 'wccp2_service dynamic <id>' entry.
7112 LOC: Config.Wccp2.weight
7116 Each cache server gets assigned a set of the destination
7117 hash proportional to their weight.
7122 LOC: Config.Wccp.address
7124 DEFAULT_DOC: Address selected by the operating system.
7127 Use this option if you require WCCPv2 to use a specific
7130 The default behavior is to not bind to any specific address.
7135 LOC: Config.Wccp2.address
7137 DEFAULT_DOC: Address selected by the operating system.
7140 Use this option if you require WCCP to use a specific
7143 The default behavior is to not bind to any specific address.
7147 PERSISTENT CONNECTION HANDLING
7148 -----------------------------------------------------------------------------
7150 Also see "pconn_timeout" in the TIMEOUTS section
7153 NAME: client_persistent_connections
7155 LOC: Config.onoff.client_pconns
7158 Persistent connection support for clients.
7159 Squid uses persistent connections (when allowed). You can use
7160 this option to disable persistent connections with clients.
7163 NAME: server_persistent_connections
7165 LOC: Config.onoff.server_pconns
7168 Persistent connection support for servers.
7169 Squid uses persistent connections (when allowed). You can use
7170 this option to disable persistent connections with servers.
7173 NAME: persistent_connection_after_error
7175 LOC: Config.onoff.error_pconns
7178 With this directive the use of persistent connections after
7179 HTTP errors can be disabled. Useful if you have clients
7180 who fail to handle errors on persistent connections proper.
7183 NAME: detect_broken_pconn
7185 LOC: Config.onoff.detect_broken_server_pconns
7188 Some servers have been found to incorrectly signal the use
7189 of HTTP/1.0 persistent connections even on replies not
7190 compatible, causing significant delays. This server problem
7191 has mostly been seen on redirects.
7193 By enabling this directive Squid attempts to detect such
7194 broken replies and automatically assume the reply is finished
7195 after 10 seconds timeout.
7199 CACHE DIGEST OPTIONS
7200 -----------------------------------------------------------------------------
7203 NAME: digest_generation
7204 IFDEF: USE_CACHE_DIGESTS
7206 LOC: Config.onoff.digest_generation
7209 This controls whether the server will generate a Cache Digest
7210 of its contents. By default, Cache Digest generation is
7211 enabled if Squid is compiled with --enable-cache-digests defined.
7214 NAME: digest_bits_per_entry
7215 IFDEF: USE_CACHE_DIGESTS
7217 LOC: Config.digest.bits_per_entry
7220 This is the number of bits of the server's Cache Digest which
7221 will be associated with the Digest entry for a given HTTP
7222 Method and URL (public key) combination. The default is 5.
7225 NAME: digest_rebuild_period
7226 IFDEF: USE_CACHE_DIGESTS
7229 LOC: Config.digest.rebuild_period
7232 This is the wait time between Cache Digest rebuilds.
7235 NAME: digest_rewrite_period
7237 IFDEF: USE_CACHE_DIGESTS
7239 LOC: Config.digest.rewrite_period
7242 This is the wait time between Cache Digest writes to
7246 NAME: digest_swapout_chunk_size
7249 IFDEF: USE_CACHE_DIGESTS
7250 LOC: Config.digest.swapout_chunk_size
7253 This is the number of bytes of the Cache Digest to write to
7254 disk at a time. It defaults to 4096 bytes (4KB), the Squid
7258 NAME: digest_rebuild_chunk_percentage
7259 COMMENT: (percent, 0-100)
7260 IFDEF: USE_CACHE_DIGESTS
7262 LOC: Config.digest.rebuild_chunk_percentage
7265 This is the percentage of the Cache Digest to be scanned at a
7266 time. By default it is set to 10% of the Cache Digest.
7271 -----------------------------------------------------------------------------
7276 LOC: Config.Port.snmp
7278 DEFAULT_DOC: SNMP disabled.
7281 The port number where Squid listens for SNMP requests. To enable
7282 SNMP support set this to a suitable port number. Port number
7283 3401 is often used for the Squid SNMP agent. By default it's
7284 set to "0" (disabled)
7292 LOC: Config.accessList.snmp
7294 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
7297 Allowing or denying access to the SNMP port.
7299 All access to the agent is denied by default.
7302 snmp_access allow|deny [!]aclname ...
7304 This clause only supports fast acl types.
7305 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7308 snmp_access allow snmppublic localhost
7309 snmp_access deny all
7312 NAME: snmp_incoming_address
7314 LOC: Config.Addrs.snmp_incoming
7316 DEFAULT_DOC: Accept SNMP packets from all machine interfaces.
7319 Just like 'udp_incoming_address', but for the SNMP port.
7321 snmp_incoming_address is used for the SNMP socket receiving
7322 messages from SNMP agents.
7324 The default snmp_incoming_address is to listen on all
7325 available network interfaces.
7328 NAME: snmp_outgoing_address
7330 LOC: Config.Addrs.snmp_outgoing
7332 DEFAULT_DOC: Use snmp_incoming_address or an address selected by the operating system.
7335 Just like 'udp_outgoing_address', but for the SNMP port.
7337 snmp_outgoing_address is used for SNMP packets returned to SNMP
7340 If snmp_outgoing_address is not set it will use the same socket
7341 as snmp_incoming_address. Only change this if you want to have
7342 SNMP replies sent using another address than where this Squid
7343 listens for SNMP queries.
7345 NOTE, snmp_incoming_address and snmp_outgoing_address can not have
7346 the same value since they both use the same port.
7351 -----------------------------------------------------------------------------
7354 NAME: icp_port udp_port
7357 DEFAULT_DOC: ICP disabled.
7358 LOC: Config.Port.icp
7360 The port number where Squid sends and receives ICP queries to
7361 and from neighbor caches. The standard UDP port for ICP is 3130.
7364 icp_port @DEFAULT_ICP_PORT@
7371 DEFAULT_DOC: HTCP disabled.
7372 LOC: Config.Port.htcp
7374 The port number where Squid sends and receives HTCP queries to
7375 and from neighbor caches. To turn it on you want to set it to
7382 NAME: log_icp_queries
7386 LOC: Config.onoff.log_udp
7388 If set, ICP queries are logged to access.log. You may wish
7389 do disable this if your ICP load is VERY high to speed things
7390 up or to simplify log analysis.
7393 NAME: udp_incoming_address
7395 LOC:Config.Addrs.udp_incoming
7397 DEFAULT_DOC: Accept packets from all machine interfaces.
7399 udp_incoming_address is used for UDP packets received from other
7402 The default behavior is to not bind to any specific address.
7404 Only change this if you want to have all UDP queries received on
7405 a specific interface/address.
7407 NOTE: udp_incoming_address is used by the ICP, HTCP, and DNS
7408 modules. Altering it will affect all of them in the same manner.
7410 see also; udp_outgoing_address
7412 NOTE, udp_incoming_address and udp_outgoing_address can not
7413 have the same value since they both use the same port.
7416 NAME: udp_outgoing_address
7418 LOC: Config.Addrs.udp_outgoing
7420 DEFAULT_DOC: Use udp_incoming_address or an address selected by the operating system.
7422 udp_outgoing_address is used for UDP packets sent out to other
7425 The default behavior is to not bind to any specific address.
7427 Instead it will use the same socket as udp_incoming_address.
7428 Only change this if you want to have UDP queries sent using another
7429 address than where this Squid listens for UDP queries from other
7432 NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS
7433 modules. Altering it will affect all of them in the same manner.
7435 see also; udp_incoming_address
7437 NOTE, udp_incoming_address and udp_outgoing_address can not
7438 have the same value since they both use the same port.
7445 LOC: Config.onoff.icp_hit_stale
7447 If you want to return ICP_HIT for stale cache objects, set this
7448 option to 'on'. If you have sibling relationships with caches
7449 in other administrative domains, this should be 'off'. If you only
7450 have sibling relationships with caches under your control,
7451 it is probably okay to set this to 'on'.
7452 If set to 'on', your siblings should use the option "allow-miss"
7453 on their cache_peer lines for connecting to you.
7456 NAME: minimum_direct_hops
7459 LOC: Config.minDirectHops
7461 If using the ICMP pinging stuff, do direct fetches for sites
7462 which are no more than this many hops away.
7465 NAME: minimum_direct_rtt
7469 LOC: Config.minDirectRtt
7471 If using the ICMP pinging stuff, do direct fetches for sites
7472 which are no more than this many rtt milliseconds away.
7478 LOC: Config.Netdb.low
7480 The low water mark for the ICMP measurement database.
7482 Note: high watermark controlled by netdb_high directive.
7484 These watermarks are counts, not percents. The defaults are
7485 (low) 900 and (high) 1000. When the high water mark is
7486 reached, database entries will be deleted until the low
7493 LOC: Config.Netdb.high
7495 The high water mark for the ICMP measurement database.
7497 Note: low watermark controlled by netdb_low directive.
7499 These watermarks are counts, not percents. The defaults are
7500 (low) 900 and (high) 1000. When the high water mark is
7501 reached, database entries will be deleted until the low
7505 NAME: netdb_ping_period
7507 LOC: Config.Netdb.period
7510 The minimum period for measuring a site. There will be at
7511 least this much delay between successive pings to the same
7512 network. The default is five minutes.
7519 LOC: Config.onoff.query_icmp
7521 If you want to ask your peers to include ICMP data in their ICP
7522 replies, enable this option.
7524 If your peer has configured Squid (during compilation) with
7525 '--enable-icmp' that peer will send ICMP pings to origin server
7526 sites of the URLs it receives. If you enable this option the
7527 ICP replies from that peer will include the ICMP data (if available).
7528 Then, when choosing a parent cache, Squid will choose the parent with
7529 the minimal RTT to the origin server. When this happens, the
7530 hierarchy field of the access.log will be
7531 "CLOSEST_PARENT_MISS". This option is off by default.
7534 NAME: test_reachability
7538 LOC: Config.onoff.test_reachability
7540 When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
7541 instead of ICP_MISS if the target host is NOT in the ICMP
7542 database, or has a zero RTT.
7545 NAME: icp_query_timeout
7548 DEFAULT_DOC: Dynamic detection.
7550 LOC: Config.Timeout.icp_query
7552 Normally Squid will automatically determine an optimal ICP
7553 query timeout value based on the round-trip-time of recent ICP
7554 queries. If you want to override the value determined by
7555 Squid, set this 'icp_query_timeout' to a non-zero value. This
7556 value is specified in MILLISECONDS, so, to use a 2-second
7557 timeout (the old default), you would write:
7559 icp_query_timeout 2000
7562 NAME: maximum_icp_query_timeout
7566 LOC: Config.Timeout.icp_query_max
7568 Normally the ICP query timeout is determined dynamically. But
7569 sometimes it can lead to very large values (say 5 seconds).
7570 Use this option to put an upper limit on the dynamic timeout
7571 value. Do NOT use this option to always use a fixed (instead
7572 of a dynamic) timeout value. To set a fixed timeout see the
7573 'icp_query_timeout' directive.
7576 NAME: minimum_icp_query_timeout
7580 LOC: Config.Timeout.icp_query_min
7582 Normally the ICP query timeout is determined dynamically. But
7583 sometimes it can lead to very small timeouts, even lower than
7584 the normal latency variance on your link due to traffic.
7585 Use this option to put an lower limit on the dynamic timeout
7586 value. Do NOT use this option to always use a fixed (instead
7587 of a dynamic) timeout value. To set a fixed timeout see the
7588 'icp_query_timeout' directive.
7591 NAME: background_ping_rate
7595 LOC: Config.backgroundPingRate
7597 Controls how often the ICP pings are sent to siblings that
7598 have background-ping set.
7602 MULTICAST ICP OPTIONS
7603 -----------------------------------------------------------------------------
7608 LOC: Config.mcast_group_list
7611 This tag specifies a list of multicast groups which your server
7612 should join to receive multicasted ICP queries.
7614 NOTE! Be very careful what you put here! Be sure you
7615 understand the difference between an ICP _query_ and an ICP
7616 _reply_. This option is to be set only if you want to RECEIVE
7617 multicast queries. Do NOT set this option to SEND multicast
7618 ICP (use cache_peer for that). ICP replies are always sent via
7619 unicast, so this option does not affect whether or not you will
7620 receive replies from multicast group members.
7622 You must be very careful to NOT use a multicast address which
7623 is already in use by another group of caches.
7625 If you are unsure about multicast, please read the Multicast
7626 chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
7628 Usage: mcast_groups 239.128.16.128 224.0.1.20
7630 By default, Squid doesn't listen on any multicast groups.
7633 NAME: mcast_miss_addr
7634 IFDEF: MULTICAST_MISS_STREAM
7636 LOC: Config.mcast_miss.addr
7638 DEFAULT_DOC: disabled.
7640 If you enable this option, every "cache miss" URL will
7641 be sent out on the specified multicast address.
7643 Do not enable this option unless you are are absolutely
7644 certain you understand what you are doing.
7647 NAME: mcast_miss_ttl
7648 IFDEF: MULTICAST_MISS_STREAM
7650 LOC: Config.mcast_miss.ttl
7653 This is the time-to-live value for packets multicasted
7654 when multicasting off cache miss URLs is enabled. By
7655 default this is set to 'site scope', i.e. 16.
7658 NAME: mcast_miss_port
7659 IFDEF: MULTICAST_MISS_STREAM
7661 LOC: Config.mcast_miss.port
7664 This is the port number to be used in conjunction with
7668 NAME: mcast_miss_encode_key
7669 IFDEF: MULTICAST_MISS_STREAM
7671 LOC: Config.mcast_miss.encode_key
7672 DEFAULT: XXXXXXXXXXXXXXXX
7674 The URLs that are sent in the multicast miss stream are
7675 encrypted. This is the encryption key.
7678 NAME: mcast_icp_query_timeout
7682 LOC: Config.Timeout.mcast_icp_query
7684 For multicast peers, Squid regularly sends out ICP "probes" to
7685 count how many other peers are listening on the given multicast
7686 address. This value specifies how long Squid should wait to
7687 count all the replies. The default is 2000 msec, or 2
7692 INTERNAL ICON OPTIONS
7693 -----------------------------------------------------------------------------
7696 NAME: icon_directory
7698 LOC: Config.icons.directory
7699 DEFAULT: @DEFAULT_ICON_DIR@
7701 Where the icons are stored. These are normally kept in
7705 NAME: global_internal_static
7707 LOC: Config.onoff.global_internal_static
7710 This directive controls is Squid should intercept all requests for
7711 /squid-internal-static/ no matter which host the URL is requesting
7712 (default on setting), or if nothing special should be done for
7713 such URLs (off setting). The purpose of this directive is to make
7714 icons etc work better in complex cache hierarchies where it may
7715 not always be possible for all corners in the cache mesh to reach
7716 the server generating a directory listing.
7719 NAME: short_icon_urls
7721 LOC: Config.icons.use_short_names
7724 If this is enabled Squid will use short URLs for icons.
7725 If disabled it will revert to the old behavior of including
7726 it's own name and port in the URL.
7728 If you run a complex cache hierarchy with a mix of Squid and
7729 other proxies you may need to disable this directive.
7734 -----------------------------------------------------------------------------
7737 NAME: error_directory
7739 LOC: Config.errorDirectory
7741 DEFAULT_DOC: Send error pages in the clients preferred language
7743 If you wish to create your own versions of the default
7744 error files to customize them to suit your company copy
7745 the error/template files to another directory and point
7748 WARNING: This option will disable multi-language support
7749 on error pages if used.
7751 The squid developers are interested in making squid available in
7752 a wide variety of languages. If you are making translations for a
7753 language that Squid does not currently provide please consider
7754 contributing your translation back to the project.
7755 http://wiki.squid-cache.org/Translations
7757 The squid developers working on translations are happy to supply drop-in
7758 translated error files in exchange for any new language contributions.
7761 NAME: error_default_language
7762 IFDEF: USE_ERR_LOCALES
7764 LOC: Config.errorDefaultLanguage
7766 DEFAULT_DOC: Generate English language pages.
7768 Set the default language which squid will send error pages in
7769 if no existing translation matches the clients language
7772 If unset (default) generic English will be used.
7774 The squid developers are interested in making squid available in
7775 a wide variety of languages. If you are interested in making
7776 translations for any language see the squid wiki for details.
7777 http://wiki.squid-cache.org/Translations
7780 NAME: error_log_languages
7781 IFDEF: USE_ERR_LOCALES
7783 LOC: Config.errorLogMissingLanguages
7786 Log to cache.log what languages users are attempting to
7787 auto-negotiate for translations.
7789 Successful negotiations are not logged. Only failures
7790 have meaning to indicate that Squid may need an upgrade
7791 of its error page translations.
7794 NAME: err_page_stylesheet
7796 LOC: Config.errorStylesheet
7797 DEFAULT: @DEFAULT_CONFIG_DIR@/errorpage.css
7799 CSS Stylesheet to pattern the display of Squid default error pages.
7801 For information on CSS see http://www.w3.org/Style/CSS/
7806 LOC: Config.errHtmlText
7809 HTML text to include in error messages. Make this a "mailto"
7810 URL to your admin address, or maybe just a link to your
7811 organizations Web page.
7813 To include this in your error messages, you must rewrite
7814 the error template files (found in the "errors" directory).
7815 Wherever you want the 'err_html_text' line to appear,
7816 insert a %L tag in the error template file.
7819 NAME: email_err_data
7822 LOC: Config.onoff.emailErrData
7825 If enabled, information about the occurred error will be
7826 included in the mailto links of the ERR pages (if %W is set)
7827 so that the email body contains the data.
7828 Syntax is <A HREF="mailto:%w%W">%w</A>
7833 LOC: Config.denyInfoList
7836 Usage: deny_info err_page_name acl
7837 or deny_info http://... acl
7838 or deny_info TCP_RESET acl
7840 This can be used to return a ERR_ page for requests which
7841 do not pass the 'http_access' rules. Squid remembers the last
7842 acl it evaluated in http_access, and if a 'deny_info' line exists
7843 for that ACL Squid returns a corresponding error page.
7845 The acl is typically the last acl on the http_access deny line which
7846 denied access. The exceptions to this rule are:
7847 - When Squid needs to request authentication credentials. It's then
7848 the first authentication related acl encountered
7849 - When none of the http_access lines matches. It's then the last
7850 acl processed on the last http_access line.
7851 - When the decision to deny access was made by an adaptation service,
7852 the acl name is the corresponding eCAP or ICAP service_name.
7854 NP: If providing your own custom error pages with error_directory
7855 you may also specify them by your custom file name:
7856 Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
7858 By defaut Squid will send "403 Forbidden". A different 4xx or 5xx
7859 may be specified by prefixing the file name with the code and a colon.
7860 e.g. 404:ERR_CUSTOM_ACCESS_DENIED
7862 Alternatively you can tell Squid to reset the TCP connection
7863 by specifying TCP_RESET.
7865 Or you can specify an error URL or URL pattern. The browsers will
7866 get redirected to the specified URL after formatting tags have
7867 been replaced. Redirect will be done with 302 or 307 according to
7868 HTTP/1.1 specs. A different 3xx code may be specified by prefixing
7869 the URL. e.g. 303:http://example.com/
7872 %a - username (if available. Password NOT included)
7875 %E - Error description
7877 %H - Request domain name
7878 %i - Client IP Address
7880 %o - Message result from external ACL helper
7881 %p - Request Port number
7882 %P - Request Protocol name
7883 %R - Request URL path
7884 %T - Timestamp in RFC 1123 format
7885 %U - Full canonical URL from client
7886 (HTTPS URLs terminate with *)
7887 %u - Full canonical URL from client
7888 %w - Admin email from squid.conf
7890 %% - Literal percent (%) code
7895 OPTIONS INFLUENCING REQUEST FORWARDING
7896 -----------------------------------------------------------------------------
7899 NAME: nonhierarchical_direct
7901 LOC: Config.onoff.nonhierarchical_direct
7904 By default, Squid will send any non-hierarchical requests
7905 (not cacheable request type) direct to origin servers.
7907 When this is set to "off", Squid will prefer to send these
7908 requests to parents.
7910 Note that in most configurations, by turning this off you will only
7911 add latency to these request without any improvement in global hit
7914 This option only sets a preference. If the parent is unavailable a
7915 direct connection to the origin server may still be attempted. To
7916 completely prevent direct connections use never_direct.
7921 LOC: Config.onoff.prefer_direct
7924 Normally Squid tries to use parents for most requests. If you for some
7925 reason like it to first try going direct and only use a parent if
7926 going direct fails set this to on.
7928 By combining nonhierarchical_direct off and prefer_direct on you
7929 can set up Squid to use a parent as a backup path if going direct
7932 Note: If you want Squid to use parents for all requests see
7933 the never_direct directive. prefer_direct only modifies how Squid
7934 acts on cacheable requests.
7937 NAME: cache_miss_revalidate
7941 LOC: Config.onoff.cache_miss_revalidate
7943 RFC 7232 defines a conditional request mechanism to prevent
7944 response objects being unnecessarily transferred over the network.
7945 If that mechanism is used by the client and a cache MISS occurs
7946 it can prevent new cache entries being created.
7948 This option determines whether Squid on cache MISS will pass the
7949 client revalidation request to the server or tries to fetch new
7950 content for caching. It can be useful while the cache is mostly
7951 empty to more quickly have the cache populated by generating
7952 non-conditional GETs.
7954 When set to 'on' (default), Squid will pass all client If-* headers
7955 to the server. This permits server responses without a cacheable
7956 payload to be delivered and on MISS no new cache entry is created.
7958 When set to 'off' and if the request is cacheable, Squid will
7959 remove the clients If-Modified-Since and If-None-Match headers from
7960 the request sent to the server. This requests a 200 status response
7961 from the server to create a new cache entry with.
7966 LOC: Config.accessList.AlwaysDirect
7968 DEFAULT_DOC: Prevent any cache_peer being used for this request.
7970 Usage: always_direct allow|deny [!]aclname ...
7972 Here you can use ACL elements to specify requests which should
7973 ALWAYS be forwarded by Squid to the origin servers without using
7974 any peers. For example, to always directly forward requests for
7975 local servers ignoring any parents or siblings you may have use
7978 acl local-servers dstdomain my.domain.net
7979 always_direct allow local-servers
7981 To always forward FTP requests directly, use
7984 always_direct allow FTP
7986 NOTE: There is a similar, but opposite option named
7987 'never_direct'. You need to be aware that "always_direct deny
7988 foo" is NOT the same thing as "never_direct allow foo". You
7989 may need to use a deny rule to exclude a more-specific case of
7990 some other rule. Example:
7992 acl local-external dstdomain external.foo.net
7993 acl local-servers dstdomain .foo.net
7994 always_direct deny local-external
7995 always_direct allow local-servers
7997 NOTE: If your goal is to make the client forward the request
7998 directly to the origin server bypassing Squid then this needs
7999 to be done in the client configuration. Squid configuration
8000 can only tell Squid how Squid should fetch the object.
8002 NOTE: This directive is not related to caching. The replies
8003 is cached as usual even if you use always_direct. To not cache
8004 the replies see the 'cache' directive.
8006 This clause supports both fast and slow acl types.
8007 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
8012 LOC: Config.accessList.NeverDirect
8014 DEFAULT_DOC: Allow DNS results to be used for this request.
8016 Usage: never_direct allow|deny [!]aclname ...
8018 never_direct is the opposite of always_direct. Please read
8019 the description for always_direct if you have not already.
8021 With 'never_direct' you can use ACL elements to specify
8022 requests which should NEVER be forwarded directly to origin
8023 servers. For example, to force the use of a proxy for all
8024 requests, except those in your local domain use something like:
8026 acl local-servers dstdomain .foo.net
8027 never_direct deny local-servers
8028 never_direct allow all
8030 or if Squid is inside a firewall and there are local intranet
8031 servers inside the firewall use something like:
8033 acl local-intranet dstdomain .foo.net
8034 acl local-external dstdomain external.foo.net
8035 always_direct deny local-external
8036 always_direct allow local-intranet
8037 never_direct allow all
8039 This clause supports both fast and slow acl types.
8040 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
8044 ADVANCED NETWORKING OPTIONS
8045 -----------------------------------------------------------------------------
8048 NAME: incoming_udp_average incoming_icp_average
8051 LOC: Config.comm_incoming.udp.average
8053 Heavy voodoo here. I can't even believe you are reading this.
8054 Are you crazy? Don't even think about adjusting these unless
8055 you understand the algorithms in comm_select.c first!
8058 NAME: incoming_tcp_average incoming_http_average
8061 LOC: Config.comm_incoming.tcp.average
8063 Heavy voodoo here. I can't even believe you are reading this.
8064 Are you crazy? Don't even think about adjusting these unless
8065 you understand the algorithms in comm_select.c first!
8068 NAME: incoming_dns_average
8071 LOC: Config.comm_incoming.dns.average
8073 Heavy voodoo here. I can't even believe you are reading this.
8074 Are you crazy? Don't even think about adjusting these unless
8075 you understand the algorithms in comm_select.c first!
8078 NAME: min_udp_poll_cnt min_icp_poll_cnt
8081 LOC: Config.comm_incoming.udp.min_poll
8083 Heavy voodoo here. I can't even believe you are reading this.
8084 Are you crazy? Don't even think about adjusting these unless
8085 you understand the algorithms in comm_select.c first!
8088 NAME: min_dns_poll_cnt
8091 LOC: Config.comm_incoming.dns.min_poll
8093 Heavy voodoo here. I can't even believe you are reading this.
8094 Are you crazy? Don't even think about adjusting these unless
8095 you understand the algorithms in comm_select.c first!
8098 NAME: min_tcp_poll_cnt min_http_poll_cnt
8101 LOC: Config.comm_incoming.tcp.min_poll
8103 Heavy voodoo here. I can't even believe you are reading this.
8104 Are you crazy? Don't even think about adjusting these unless
8105 you understand the algorithms in comm_select.c first!
8111 LOC: Config.accept_filter
8115 The name of an accept(2) filter to install on Squid's
8116 listen socket(s). This feature is perhaps specific to
8117 FreeBSD and requires support in the kernel.
8119 The 'httpready' filter delays delivering new connections
8120 to Squid until a full HTTP request has been received.
8121 See the accf_http(9) man page for details.
8123 The 'dataready' filter delays delivering new connections
8124 to Squid until there is some data to process.
8125 See the accf_dataready(9) man page for details.
8129 The 'data' filter delays delivering of new connections
8130 to Squid until there is some data to process by TCP_ACCEPT_DEFER.
8131 You may optionally specify a number of seconds to wait by
8132 'data=N' where N is the number of seconds. Defaults to 30
8133 if not specified. See the tcp(7) man page for details.
8136 accept_filter httpready
8141 NAME: client_ip_max_connections
8143 LOC: Config.client_ip_max_connections
8145 DEFAULT_DOC: No limit.
8147 Set an absolute limit on the number of connections a single
8148 client IP can use. Any more than this and Squid will begin to drop
8149 new connections from the client until it closes some links.
8151 Note that this is a global limit. It affects all HTTP, HTCP, Gopher and FTP
8152 connections from the client. For finer control use the ACL access controls.
8154 Requires client_db to be enabled (the default).
8156 WARNING: This may noticably slow down traffic received via external proxies
8157 or NAT devices and cause them to rebound error messages back to their clients.
8160 NAME: tcp_recv_bufsize
8164 DEFAULT_DOC: Use operating system TCP defaults.
8165 LOC: Config.tcpRcvBufsz
8167 Size of receive buffer to set for TCP sockets. Probably just
8168 as easy to change your kernel's default.
8169 Omit from squid.conf to use the default buffer size.
8174 -----------------------------------------------------------------------------
8181 LOC: Adaptation::Icap::TheConfig.onoff
8184 If you want to enable the ICAP module support, set this to on.
8187 NAME: icap_connect_timeout
8190 LOC: Adaptation::Icap::TheConfig.connect_timeout_raw
8193 This parameter specifies how long to wait for the TCP connect to
8194 the requested ICAP server to complete before giving up and either
8195 terminating the HTTP transaction or bypassing the failure.
8197 The default for optional services is peer_connect_timeout.
8198 The default for essential services is connect_timeout.
8199 If this option is explicitly set, its value applies to all services.
8202 NAME: icap_io_timeout
8206 DEFAULT_DOC: Use read_timeout.
8207 LOC: Adaptation::Icap::TheConfig.io_timeout_raw
8210 This parameter specifies how long to wait for an I/O activity on
8211 an established, active ICAP connection before giving up and
8212 either terminating the HTTP transaction or bypassing the
8216 NAME: icap_service_failure_limit
8217 COMMENT: limit [in memory-depth time-units]
8218 TYPE: icap_service_failure_limit
8220 LOC: Adaptation::Icap::TheConfig
8223 The limit specifies the number of failures that Squid tolerates
8224 when establishing a new TCP connection with an ICAP service. If
8225 the number of failures exceeds the limit, the ICAP service is
8226 not used for new ICAP requests until it is time to refresh its
8229 A negative value disables the limit. Without the limit, an ICAP
8230 service will not be considered down due to connectivity failures
8231 between ICAP OPTIONS requests.
8233 Squid forgets ICAP service failures older than the specified
8234 value of memory-depth. The memory fading algorithm
8235 is approximate because Squid does not remember individual
8236 errors but groups them instead, splitting the option
8237 value into ten time slots of equal length.
8239 When memory-depth is 0 and by default this option has no
8240 effect on service failure expiration.
8242 Squid always forgets failures when updating service settings
8243 using an ICAP OPTIONS transaction, regardless of this option
8247 # suspend service usage after 10 failures in 5 seconds:
8248 icap_service_failure_limit 10 in 5 seconds
8251 NAME: icap_service_revival_delay
8254 LOC: Adaptation::Icap::TheConfig.service_revival_delay
8257 The delay specifies the number of seconds to wait after an ICAP
8258 OPTIONS request failure before requesting the options again. The
8259 failed ICAP service is considered "down" until fresh OPTIONS are
8262 The actual delay cannot be smaller than the hardcoded minimum
8263 delay of 30 seconds.
8266 NAME: icap_preview_enable
8270 LOC: Adaptation::Icap::TheConfig.preview_enable
8273 The ICAP Preview feature allows the ICAP server to handle the
8274 HTTP message by looking only at the beginning of the message body
8275 or even without receiving the body at all. In some environments,
8276 previews greatly speedup ICAP processing.
8278 During an ICAP OPTIONS transaction, the server may tell Squid what
8279 HTTP messages should be previewed and how big the preview should be.
8280 Squid will not use Preview if the server did not request one.
8282 To disable ICAP Preview for all ICAP services, regardless of
8283 individual ICAP server OPTIONS responses, set this option to "off".
8285 icap_preview_enable off
8288 NAME: icap_preview_size
8291 LOC: Adaptation::Icap::TheConfig.preview_size
8293 DEFAULT_DOC: No preview sent.
8295 The default size of preview data to be sent to the ICAP server.
8296 This value might be overwritten on a per server basis by OPTIONS requests.
8299 NAME: icap_206_enable
8303 LOC: Adaptation::Icap::TheConfig.allow206_enable
8306 206 (Partial Content) responses is an ICAP extension that allows the
8307 ICAP agents to optionally combine adapted and original HTTP message
8308 content. The decision to combine is postponed until the end of the
8309 ICAP response. Squid supports Partial Content extension by default.
8311 Activation of the Partial Content extension is negotiated with each
8312 ICAP service during OPTIONS exchange. Most ICAP servers should handle
8313 negotation correctly even if they do not support the extension, but
8314 some might fail. To disable Partial Content support for all ICAP
8315 services and to avoid any negotiation, set this option to "off".
8321 NAME: icap_default_options_ttl
8324 LOC: Adaptation::Icap::TheConfig.default_options_ttl
8327 The default TTL value for ICAP OPTIONS responses that don't have
8328 an Options-TTL header.
8331 NAME: icap_persistent_connections
8335 LOC: Adaptation::Icap::TheConfig.reuse_connections
8338 Whether or not Squid should use persistent connections to
8342 NAME: adaptation_send_client_ip icap_send_client_ip
8344 IFDEF: USE_ADAPTATION
8346 LOC: Adaptation::Config::send_client_ip
8349 If enabled, Squid shares HTTP client IP information with adaptation
8350 services. For ICAP, Squid adds the X-Client-IP header to ICAP requests.
8351 For eCAP, Squid sets the libecap::metaClientIp transaction option.
8353 See also: adaptation_uses_indirect_client
8356 NAME: adaptation_send_username icap_send_client_username
8358 IFDEF: USE_ADAPTATION
8360 LOC: Adaptation::Config::send_username
8363 This sends authenticated HTTP client username (if available) to
8364 the adaptation service.
8366 For ICAP, the username value is encoded based on the
8367 icap_client_username_encode option and is sent using the header
8368 specified by the icap_client_username_header option.
8371 NAME: icap_client_username_header
8374 LOC: Adaptation::Icap::TheConfig.client_username_header
8375 DEFAULT: X-Client-Username
8377 ICAP request header name to use for adaptation_send_username.
8380 NAME: icap_client_username_encode
8384 LOC: Adaptation::Icap::TheConfig.client_username_encode
8387 Whether to base64 encode the authenticated client username.
8391 TYPE: icap_service_type
8393 LOC: Adaptation::Icap::TheConfig
8396 Defines a single ICAP service using the following format:
8398 icap_service id vectoring_point uri [option ...]
8401 an opaque identifier or name which is used to direct traffic to
8402 this specific service. Must be unique among all adaptation
8403 services in squid.conf.
8405 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
8406 This specifies at which point of transaction processing the
8407 ICAP service should be activated. *_postcache vectoring points
8408 are not yet supported.
8410 uri: icap://servername:port/servicepath
8411 ICAP server and service location.
8412 icaps://servername:port/servicepath
8413 The "icap:" URI scheme is used for traditional ICAP server and
8414 service location (default port is 1344, connections are not
8415 encrypted). The "icaps:" URI scheme is for Secure ICAP
8416 services that use SSL/TLS-encrypted ICAP connections (by
8417 default, on port 11344).
8419 ICAP does not allow a single service to handle both REQMOD and RESPMOD
8420 transactions. Squid does not enforce that requirement. You can specify
8421 services with the same service_url and different vectoring_points. You
8422 can even specify multiple identical services as long as their
8423 service_names differ.
8425 To activate a service, use the adaptation_access directive. To group
8426 services, use adaptation_service_chain and adaptation_service_set.
8428 Service options are separated by white space. ICAP services support
8429 the following name=value options:
8432 If set to 'on' or '1', the ICAP service is treated as
8433 optional. If the service cannot be reached or malfunctions,
8434 Squid will try to ignore any errors and process the message as
8435 if the service was not enabled. No all ICAP errors can be
8436 bypassed. If set to 0, the ICAP service is treated as
8437 essential and all ICAP errors will result in an error page
8438 returned to the HTTP client.
8440 Bypass is off by default: services are treated as essential.
8443 If set to 'on' or '1', the ICAP service is allowed to
8444 dynamically change the current message adaptation plan by
8445 returning a chain of services to be used next. The services
8446 are specified using the X-Next-Services ICAP response header
8447 value, formatted as a comma-separated list of service names.
8448 Each named service should be configured in squid.conf. Other
8449 services are ignored. An empty X-Next-Services value results
8450 in an empty plan which ends the current adaptation.
8452 Dynamic adaptation plan may cross or cover multiple supported
8453 vectoring points in their natural processing order.
8455 Routing is not allowed by default: the ICAP X-Next-Services
8456 response header is ignored.
8459 Only has effect on split-stack systems. The default on those systems
8460 is to use IPv4-only connections. When set to 'on' this option will
8461 make Squid use IPv6-only connections to contact this ICAP service.
8463 on-overload=block|bypass|wait|force
8464 If the service Max-Connections limit has been reached, do
8465 one of the following for each new ICAP transaction:
8466 * block: send an HTTP error response to the client
8467 * bypass: ignore the "over-connected" ICAP service
8468 * wait: wait (in a FIFO queue) for an ICAP connection slot
8469 * force: proceed, ignoring the Max-Connections limit
8471 In SMP mode with N workers, each worker assumes the service
8472 connection limit is Max-Connections/N, even though not all
8473 workers may use a given service.
8475 The default value is "bypass" if service is bypassable,
8476 otherwise it is set to "wait".
8480 Use the given number as the Max-Connections limit, regardless
8481 of the Max-Connections value given by the service, if any.
8483 ==== ICAPS / TLS OPTIONS ====
8485 These options are used for Secure ICAP (icaps://....) services only.
8487 tls-cert=/path/to/ssl/certificate
8488 A client SSL certificate to use when connecting to
8491 tls-key=/path/to/ssl/key
8492 The private TLS/SSL key corresponding to sslcert above.
8493 If 'tls-key' is not specified 'tls-cert' is assumed to
8494 reference a combined PEM format file containing both the
8495 certificate and the key.
8497 tls-cipher=... The list of valid TLS/SSL ciphers to use when connecting
8498 to this icap server.
8501 The minimum TLS protocol version to permit. To control
8502 SSLv3 use the ssloptions= parameter.
8503 Supported Values: 1.0 (default), 1.1, 1.2
8505 tls-options=... Specify various OpenSSL library options:
8507 NO_SSLv3 Disallow the use of SSLv3
8509 NO_TLSv1 Disallow the use of TLSv1.0
8510 NO_TLSv1_1 Disallow the use of TLSv1.1
8511 NO_TLSv1_2 Disallow the use of TLSv1.2
8514 Always create a new key when using
8515 temporary/ephemeral DH key exchanges
8517 ALL Enable various bug workarounds
8518 suggested as "harmless" by OpenSSL
8519 Be warned that this reduces SSL/TLS
8520 strength to some attacks.
8522 See the OpenSSL SSL_CTX_set_options documentation for a
8523 more complete list. Options relevant only to SSLv2 are
8526 tls-cafile=... A PEM file containing additional CA certificates to use
8527 when verifying the icap server certificate. Used
8528 to specify intermediate CA certificate(s) if not sent
8529 by the server. Or the full CA chain for the server
8530 when using the NO_DEFAULT_CA flag.
8532 tls-capath=... A directory containing additional CA certificates to
8533 use when verifying the icap server certificate.
8535 tls-crlfile=... A certificate revocation list file to use when
8536 verifying the icap server certificate.
8538 tls-flags=... Specify various flags modifying the Squid TLS implementation:
8541 Accept certificates even if they fail to
8544 Don't use the default CA list built into
8547 Don't verify the icap server certificate
8548 matches the server name
8550 tls-domain= The icap server name as advertised in it's certificate.
8551 Used for verifying the correctness of the received icap
8552 server certificate. If not specified the icap server
8553 hostname extracted from ICAP URI will be used.
8555 Older icap_service format without optional named parameters is
8556 deprecated but supported for backward compatibility.
8559 icap_service svcBlocker reqmod_precache icap://icap1.mydomain.net:1344/reqmod bypass=0
8560 icap_service svcLogger reqmod_precache icaps://icap2.mydomain.net:11344/reqmod routing=on
8564 TYPE: icap_class_type
8569 This deprecated option was documented to define an ICAP service
8570 chain, even though it actually defined a set of similar, redundant
8571 services, and the chains were not supported.
8573 To define a set of redundant services, please use the
8574 adaptation_service_set directive. For service chains, use
8575 adaptation_service_chain.
8579 TYPE: icap_access_type
8584 This option is deprecated. Please use adaptation_access, which
8585 has the same ICAP functionality, but comes with better
8586 documentation, and eCAP support.
8591 -----------------------------------------------------------------------------
8598 LOC: Adaptation::Ecap::TheConfig.onoff
8601 Controls whether eCAP support is enabled.
8605 TYPE: ecap_service_type
8607 LOC: Adaptation::Ecap::TheConfig
8610 Defines a single eCAP service
8612 ecap_service id vectoring_point uri [option ...]
8615 an opaque identifier or name which is used to direct traffic to
8616 this specific service. Must be unique among all adaptation
8617 services in squid.conf.
8619 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
8620 This specifies at which point of transaction processing the
8621 eCAP service should be activated. *_postcache vectoring points
8622 are not yet supported.
8624 uri: ecap://vendor/service_name?custom&cgi=style¶meters=optional
8625 Squid uses the eCAP service URI to match this configuration
8626 line with one of the dynamically loaded services. Each loaded
8627 eCAP service must have a unique URI. Obtain the right URI from
8628 the service provider.
8630 To activate a service, use the adaptation_access directive. To group
8631 services, use adaptation_service_chain and adaptation_service_set.
8633 Service options are separated by white space. eCAP services support
8634 the following name=value options:
8637 If set to 'on' or '1', the eCAP service is treated as optional.
8638 If the service cannot be reached or malfunctions, Squid will try
8639 to ignore any errors and process the message as if the service
8640 was not enabled. No all eCAP errors can be bypassed.
8641 If set to 'off' or '0', the eCAP service is treated as essential
8642 and all eCAP errors will result in an error page returned to the
8645 Bypass is off by default: services are treated as essential.
8648 If set to 'on' or '1', the eCAP service is allowed to
8649 dynamically change the current message adaptation plan by
8650 returning a chain of services to be used next.
8652 Dynamic adaptation plan may cross or cover multiple supported
8653 vectoring points in their natural processing order.
8655 Routing is not allowed by default.
8657 Older ecap_service format without optional named parameters is
8658 deprecated but supported for backward compatibility.
8662 ecap_service s1 reqmod_precache ecap://filters.R.us/leakDetector?on_error=block bypass=off
8663 ecap_service s2 respmod_precache ecap://filters.R.us/virusFilter config=/etc/vf.cfg bypass=on
8666 NAME: loadable_modules
8668 IFDEF: USE_LOADABLE_MODULES
8669 LOC: Config.loadable_module_names
8672 Instructs Squid to load the specified dynamic module(s) or activate
8673 preloaded module(s).
8675 loadable_modules @DEFAULT_PREFIX@/lib/MinimalAdapter.so
8679 MESSAGE ADAPTATION OPTIONS
8680 -----------------------------------------------------------------------------
8683 NAME: adaptation_service_set
8684 TYPE: adaptation_service_set_type
8685 IFDEF: USE_ADAPTATION
8690 Configures an ordered set of similar, redundant services. This is
8691 useful when hot standby or backup adaptation servers are available.
8693 adaptation_service_set set_name service_name1 service_name2 ...
8695 The named services are used in the set declaration order. The first
8696 applicable adaptation service from the set is used first. The next
8697 applicable service is tried if and only if the transaction with the
8698 previous service fails and the message waiting to be adapted is still
8701 When adaptation starts, broken services are ignored as if they were
8702 not a part of the set. A broken service is a down optional service.
8704 The services in a set must be attached to the same vectoring point
8705 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
8707 If all services in a set are optional then adaptation failures are
8708 bypassable. If all services in the set are essential, then a
8709 transaction failure with one service may still be retried using
8710 another service from the set, but when all services fail, the master
8711 transaction fails as well.
8713 A set may contain a mix of optional and essential services, but that
8714 is likely to lead to surprising results because broken services become
8715 ignored (see above), making previously bypassable failures fatal.
8716 Technically, it is the bypassability of the last failed service that
8719 See also: adaptation_access adaptation_service_chain
8722 adaptation_service_set svcBlocker urlFilterPrimary urlFilterBackup
8723 adaptation service_set svcLogger loggerLocal loggerRemote
8726 NAME: adaptation_service_chain
8727 TYPE: adaptation_service_chain_type
8728 IFDEF: USE_ADAPTATION
8733 Configures a list of complementary services that will be applied
8734 one-by-one, forming an adaptation chain or pipeline. This is useful
8735 when Squid must perform different adaptations on the same message.
8737 adaptation_service_chain chain_name service_name1 svc_name2 ...
8739 The named services are used in the chain declaration order. The first
8740 applicable adaptation service from the chain is used first. The next
8741 applicable service is applied to the successful adaptation results of
8742 the previous service in the chain.
8744 When adaptation starts, broken services are ignored as if they were
8745 not a part of the chain. A broken service is a down optional service.
8747 Request satisfaction terminates the adaptation chain because Squid
8748 does not currently allow declaration of RESPMOD services at the
8749 "reqmod_precache" vectoring point (see icap_service or ecap_service).
8751 The services in a chain must be attached to the same vectoring point
8752 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
8754 A chain may contain a mix of optional and essential services. If an
8755 essential adaptation fails (or the failure cannot be bypassed for
8756 other reasons), the master transaction fails. Otherwise, the failure
8757 is bypassed as if the failed adaptation service was not in the chain.
8759 See also: adaptation_access adaptation_service_set
8762 adaptation_service_chain svcRequest requestLogger urlFilter leakDetector
8765 NAME: adaptation_access
8766 TYPE: adaptation_access_type
8767 IFDEF: USE_ADAPTATION
8770 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
8772 Sends an HTTP transaction to an ICAP or eCAP adaptation service.
8774 adaptation_access service_name allow|deny [!]aclname...
8775 adaptation_access set_name allow|deny [!]aclname...
8777 At each supported vectoring point, the adaptation_access
8778 statements are processed in the order they appear in this
8779 configuration file. Statements pointing to the following services
8780 are ignored (i.e., skipped without checking their ACL):
8782 - services serving different vectoring points
8783 - "broken-but-bypassable" services
8784 - "up" services configured to ignore such transactions
8785 (e.g., based on the ICAP Transfer-Ignore header).
8787 When a set_name is used, all services in the set are checked
8788 using the same rules, to find the first applicable one. See
8789 adaptation_service_set for details.
8791 If an access list is checked and there is a match, the
8792 processing stops: For an "allow" rule, the corresponding
8793 adaptation service is used for the transaction. For a "deny"
8794 rule, no adaptation service is activated.
8796 It is currently not possible to apply more than one adaptation
8797 service at the same vectoring point to the same HTTP transaction.
8799 See also: icap_service and ecap_service
8802 adaptation_access service_1 allow all
8805 NAME: adaptation_service_iteration_limit
8807 IFDEF: USE_ADAPTATION
8808 LOC: Adaptation::Config::service_iteration_limit
8811 Limits the number of iterations allowed when applying adaptation
8812 services to a message. If your longest adaptation set or chain
8813 may have more than 16 services, increase the limit beyond its
8814 default value of 16. If detecting infinite iteration loops sooner
8815 is critical, make the iteration limit match the actual number
8816 of services in your longest adaptation set or chain.
8818 Infinite adaptation loops are most likely with routing services.
8820 See also: icap_service routing=1
8823 NAME: adaptation_masterx_shared_names
8825 IFDEF: USE_ADAPTATION
8826 LOC: Adaptation::Config::masterx_shared_name
8829 For each master transaction (i.e., the HTTP request and response
8830 sequence, including all related ICAP and eCAP exchanges), Squid
8831 maintains a table of metadata. The table entries are (name, value)
8832 pairs shared among eCAP and ICAP exchanges. The table is destroyed
8833 with the master transaction.
8835 This option specifies the table entry names that Squid must accept
8836 from and forward to the adaptation transactions.
8838 An ICAP REQMOD or RESPMOD transaction may set an entry in the
8839 shared table by returning an ICAP header field with a name
8840 specified in adaptation_masterx_shared_names.
8842 An eCAP REQMOD or RESPMOD transaction may set an entry in the
8843 shared table by implementing the libecap::visitEachOption() API
8844 to provide an option with a name specified in
8845 adaptation_masterx_shared_names.
8847 Squid will store and forward the set entry to subsequent adaptation
8848 transactions within the same master transaction scope.
8850 Only one shared entry name is supported at this time.
8853 # share authentication information among ICAP services
8854 adaptation_masterx_shared_names X-Subscriber-ID
8857 NAME: adaptation_meta
8859 IFDEF: USE_ADAPTATION
8860 LOC: Adaptation::Config::metaHeaders
8863 This option allows Squid administrator to add custom ICAP request
8864 headers or eCAP options to Squid ICAP requests or eCAP transactions.
8865 Use it to pass custom authentication tokens and other
8866 transaction-state related meta information to an ICAP/eCAP service.
8868 The addition of a meta header is ACL-driven:
8869 adaptation_meta name value [!]aclname ...
8871 Processing for a given header name stops after the first ACL list match.
8872 Thus, it is impossible to add two headers with the same name. If no ACL
8873 lists match for a given header name, no such header is added. For
8876 # do not debug transactions except for those that need debugging
8877 adaptation_meta X-Debug 1 needs_debugging
8879 # log all transactions except for those that must remain secret
8880 adaptation_meta X-Log 1 !keep_secret
8882 # mark transactions from users in the "G 1" group
8883 adaptation_meta X-Authenticated-Groups "G 1" authed_as_G1
8885 The "value" parameter may be a regular squid.conf token or a "double
8886 quoted string". Within the quoted string, use backslash (\) to escape
8887 any character, which is currently only useful for escaping backslashes
8888 and double quotes. For example,
8889 "this string has one backslash (\\) and two \"quotes\""
8891 Used adaptation_meta header values may be logged via %note
8892 logformat code. If multiple adaptation_meta headers with the same name
8893 are used during master transaction lifetime, the header values are
8894 logged in the order they were used and duplicate values are ignored
8895 (only the first repeated value will be logged).
8901 LOC: Adaptation::Icap::TheConfig.repeat
8902 DEFAULT_IF_NONE: deny all
8904 This ACL determines which retriable ICAP transactions are
8905 retried. Transactions that received a complete ICAP response
8906 and did not have to consume or produce HTTP bodies to receive
8907 that response are usually retriable.
8909 icap_retry allow|deny [!]aclname ...
8911 Squid automatically retries some ICAP I/O timeouts and errors
8912 due to persistent connection race conditions.
8914 See also: icap_retry_limit
8917 NAME: icap_retry_limit
8920 LOC: Adaptation::Icap::TheConfig.repeat_limit
8922 DEFAULT_DOC: No retries are allowed.
8924 Limits the number of retries allowed.
8926 Communication errors due to persistent connection race
8927 conditions are unavoidable, automatically retried, and do not
8928 count against this limit.
8930 See also: icap_retry
8936 -----------------------------------------------------------------------------
8939 NAME: check_hostnames
8942 LOC: Config.onoff.check_hostnames
8944 For security and stability reasons Squid can check
8945 hostnames for Internet standard RFC compliance. If you want
8946 Squid to perform these checks turn this directive on.
8949 NAME: allow_underscore
8952 LOC: Config.onoff.allow_underscore
8954 Underscore characters is not strictly allowed in Internet hostnames
8955 but nevertheless used by many sites. Set this to off if you want
8956 Squid to be strict about the standard.
8957 This check is performed only when check_hostnames is set to on.
8960 NAME: dns_retransmit_interval
8963 LOC: Config.Timeout.idns_retransmit
8965 Initial retransmit interval for DNS queries. The interval is
8966 doubled each time all configured DNS servers have been tried.
8972 LOC: Config.Timeout.idns_query
8974 DNS Query timeout. If no response is received to a DNS query
8975 within this time all DNS servers for the queried domain
8976 are assumed to be unavailable.
8979 NAME: dns_packet_max
8981 DEFAULT_DOC: EDNS disabled
8983 LOC: Config.dns.packet_max
8985 Maximum number of bytes packet size to advertise via EDNS.
8986 Set to "none" to disable EDNS large packet support.
8988 For legacy reasons DNS UDP replies will default to 512 bytes which
8989 is too small for many responses. EDNS provides a means for Squid to
8990 negotiate receiving larger responses back immediately without having
8991 to failover with repeat requests. Responses larger than this limit
8992 will retain the old behaviour of failover to TCP DNS.
8994 Squid has no real fixed limit internally, but allowing packet sizes
8995 over 1500 bytes requires network jumbogram support and is usually not
8998 WARNING: The RFC also indicates that some older resolvers will reply
8999 with failure of the whole request if the extension is added. Some
9000 resolvers have already been identified which will reply with mangled
9001 EDNS response on occasion. Usually in response to many-KB jumbogram
9002 sizes being advertised by Squid.
9003 Squid will currently treat these both as an unable-to-resolve domain
9004 even if it would be resolvable without EDNS.
9011 DEFAULT_DOC: Search for single-label domain names is disabled.
9012 LOC: Config.onoff.res_defnames
9014 Normally the RES_DEFNAMES resolver option is disabled
9015 (see res_init(3)). This prevents caches in a hierarchy
9016 from interpreting single-component hostnames locally. To allow
9017 Squid to handle single-component names, enable this option.
9020 NAME: dns_multicast_local
9024 DEFAULT_DOC: Search for .local and .arpa names is disabled.
9025 LOC: Config.onoff.dns_mdns
9027 When set to on, Squid sends multicast DNS lookups on the local
9028 network for domains ending in .local and .arpa.
9029 This enables local servers and devices to be contacted in an
9030 ad-hoc or zero-configuration network environment.
9033 NAME: dns_nameservers
9036 DEFAULT_DOC: Use operating system definitions
9037 LOC: Config.dns_nameservers
9039 Use this if you want to specify a list of DNS name servers
9040 (IP addresses) to use instead of those given in your
9041 /etc/resolv.conf file.
9043 On Windows platforms, if no value is specified here or in
9044 the /etc/resolv.conf file, the list of DNS name servers are
9045 taken from the Windows registry, both static and dynamic DHCP
9046 configurations are supported.
9048 Example: dns_nameservers 10.0.0.1 192.172.0.4
9053 DEFAULT: @DEFAULT_HOSTS@
9054 LOC: Config.etcHostsPath
9056 Location of the host-local IP name-address associations
9057 database. Most Operating Systems have such a file on different
9059 - Un*X & Linux: /etc/hosts
9060 - Windows NT/2000: %SystemRoot%\system32\drivers\etc\hosts
9061 (%SystemRoot% value install default is c:\winnt)
9062 - Windows XP/2003: %SystemRoot%\system32\drivers\etc\hosts
9063 (%SystemRoot% value install default is c:\windows)
9064 - Windows 9x/Me: %windir%\hosts
9065 (%windir% value is usually c:\windows)
9066 - Cygwin: /etc/hosts
9068 The file contains newline-separated definitions, in the
9069 form ip_address_in_dotted_form name [name ...] names are
9070 whitespace-separated. Lines beginning with an hash (#)
9071 character are comments.
9073 The file is checked at startup and upon configuration.
9074 If set to 'none', it won't be checked.
9075 If append_domain is used, that domain will be added to
9076 domain-local (i.e. not containing any dot character) host
9082 LOC: Config.appendDomain
9084 DEFAULT_DOC: Use operating system definitions
9086 Appends local domain name to hostnames without any dots in
9087 them. append_domain must begin with a period.
9089 Be warned there are now Internet names with no dots in
9090 them using only top-domain names, so setting this may
9091 cause some Internet sites to become unavailable.
9094 append_domain .yourdomain.com
9097 NAME: ignore_unknown_nameservers
9099 LOC: Config.onoff.ignore_unknown_nameservers
9102 By default Squid checks that DNS responses are received
9103 from the same IP addresses they are sent to. If they
9104 don't match, Squid ignores the response and writes a warning
9105 message to cache.log. You can allow responses from unknown
9106 nameservers by setting this option to 'off'.
9112 LOC: Config.dns.v4_first
9114 With the IPv6 Internet being as fast or faster than IPv4 Internet
9115 for most networks Squid prefers to contact websites over IPv6.
9117 This option reverses the order of preference to make Squid contact
9118 dual-stack websites over IPv4 first. Squid will still perform both
9119 IPv6 and IPv4 DNS lookups before connecting.
9122 This option will restrict the situations under which IPv6
9123 connectivity is used (and tested). Hiding network problems
9124 which would otherwise be detected and warned about.
9128 COMMENT: (number of entries)
9131 LOC: Config.ipcache.size
9133 Maximum number of DNS IP cache entries.
9140 LOC: Config.ipcache.low
9147 LOC: Config.ipcache.high
9149 The size, low-, and high-water marks for the IP cache.
9152 NAME: fqdncache_size
9153 COMMENT: (number of entries)
9156 LOC: Config.fqdncache.size
9158 Maximum number of FQDN cache entries.
9163 -----------------------------------------------------------------------------
9166 NAME: configuration_includes_quoted_values
9168 TYPE: configuration_includes_quoted_values
9170 LOC: ConfigParser::RecognizeQuotedValues
9172 If set, Squid will recognize each "quoted string" after a configuration
9173 directive as a single parameter. The quotes are stripped before the
9174 parameter value is interpreted or used.
9175 See "Values with spaces, quotes, and other special characters"
9176 section for more details.
9183 LOC: Config.onoff.mem_pools
9185 If set, Squid will keep pools of allocated (but unused) memory
9186 available for future use. If memory is a premium on your
9187 system and you believe your malloc library outperforms Squid
9188 routines, disable this.
9191 NAME: memory_pools_limit
9195 LOC: Config.MemPools.limit
9197 Used only with memory_pools on:
9198 memory_pools_limit 50 MB
9200 If set to a non-zero value, Squid will keep at most the specified
9201 limit of allocated (but unused) memory in memory pools. All free()
9202 requests that exceed this limit will be handled by your malloc
9203 library. Squid does not pre-allocate any memory, just safe-keeps
9204 objects that otherwise would be free()d. Thus, it is safe to set
9205 memory_pools_limit to a reasonably high value even if your
9206 configuration will use less memory.
9208 If set to none, Squid will keep all memory it can. That is, there
9209 will be no limit on the total amount of memory used for safe-keeping.
9211 To disable memory allocation optimization, do not set
9212 memory_pools_limit to 0 or none. Set memory_pools to "off" instead.
9214 An overhead for maintaining memory pools is not taken into account
9215 when the limit is checked. This overhead is close to four bytes per
9216 object kept. However, pools may actually _save_ memory because of
9217 reduced memory thrashing in your malloc library.
9221 COMMENT: on|off|transparent|truncate|delete
9224 LOC: opt_forwarded_for
9226 If set to "on", Squid will append your client's IP address
9227 in the HTTP requests it forwards. By default it looks like:
9229 X-Forwarded-For: 192.1.2.3
9231 If set to "off", it will appear as
9233 X-Forwarded-For: unknown
9235 If set to "transparent", Squid will not alter the
9236 X-Forwarded-For header in any way.
9238 If set to "delete", Squid will delete the entire
9239 X-Forwarded-For header.
9241 If set to "truncate", Squid will remove all existing
9242 X-Forwarded-For entries, and place the client IP as the sole entry.
9245 NAME: cachemgr_passwd
9246 TYPE: cachemgrpasswd
9248 DEFAULT_DOC: No password. Actions which require password are denied.
9249 LOC: Config.passwd_list
9251 Specify passwords for cachemgr operations.
9253 Usage: cachemgr_passwd password action action ...
9255 Some valid actions are (see cache manager menu for a full list):
9295 * Indicates actions which will not be performed without a
9296 valid password, others can be performed if not listed here.
9298 To disable an action, set the password to "disable".
9299 To allow performing an action without a password, set the
9302 Use the keyword "all" to set the same password for all actions.
9305 cachemgr_passwd secret shutdown
9306 cachemgr_passwd lesssssssecret info stats/objects
9307 cachemgr_passwd disable all
9314 LOC: Config.onoff.client_db
9316 If you want to disable collecting per-client statistics,
9317 turn off client_db here.
9320 NAME: refresh_all_ims
9324 LOC: Config.onoff.refresh_all_ims
9326 When you enable this option, squid will always check
9327 the origin server for an update when a client sends an
9328 If-Modified-Since request. Many browsers use IMS
9329 requests when the user requests a reload, and this
9330 ensures those clients receive the latest version.
9332 By default (off), squid may return a Not Modified response
9333 based on the age of the cached version.
9336 NAME: reload_into_ims
9337 IFDEF: USE_HTTP_VIOLATIONS
9341 LOC: Config.onoff.reload_into_ims
9343 When you enable this option, client no-cache or ``reload''
9344 requests will be changed to If-Modified-Since requests.
9345 Doing this VIOLATES the HTTP standard. Enabling this
9346 feature could make you liable for problems which it
9349 see also refresh_pattern for a more selective approach.
9352 NAME: connect_retries
9354 LOC: Config.connect_retries
9356 DEFAULT_DOC: Do not retry failed connections.
9358 This sets the maximum number of connection attempts made for each
9359 TCP connection. The connect_retries attempts must all still
9360 complete within the connection timeout period.
9362 The default is not to re-try if the first connection attempt fails.
9363 The (not recommended) maximum is 10 tries.
9365 A warning message will be generated if it is set to a too-high
9366 value and the configured value will be over-ridden.
9368 Note: These re-tries are in addition to forward_max_tries
9369 which limit how many different addresses may be tried to find
9373 NAME: retry_on_error
9375 LOC: Config.retry.onerror
9378 If set to ON Squid will automatically retry requests when
9379 receiving an error response with status 403 (Forbidden),
9380 500 (Internal Error), 501 or 503 (Service not available).
9381 Status 502 and 504 (Gateway errors) are always retried.
9383 This is mainly useful if you are in a complex cache hierarchy to
9384 work around access control errors.
9386 NOTE: This retry will attempt to find another working destination.
9387 Which is different from the server which just failed.
9390 NAME: as_whois_server
9392 LOC: Config.as_whois_server
9393 DEFAULT: whois.ra.net
9395 WHOIS server to query for AS numbers. NOTE: AS numbers are
9396 queried only when Squid starts up, not for every request.
9401 LOC: Config.onoff.offline
9404 Enable this option and Squid will never try to validate cached
9408 NAME: uri_whitespace
9409 TYPE: uri_whitespace
9410 LOC: Config.uri_whitespace
9413 What to do with requests that have whitespace characters in the
9416 strip: The whitespace characters are stripped out of the URL.
9417 This is the behavior recommended by RFC2396 and RFC3986
9418 for tolerant handling of generic URI.
9419 NOTE: This is one difference between generic URI and HTTP URLs.
9421 deny: The request is denied. The user receives an "Invalid
9423 This is the behaviour recommended by RFC2616 for safe
9424 handling of HTTP request URL.
9426 allow: The request is allowed and the URI is not changed. The
9427 whitespace characters remain in the URI. Note the
9428 whitespace is passed to redirector processes if they
9430 Note this may be considered a violation of RFC2616
9431 request parsing where whitespace is prohibited in the
9434 encode: The request is allowed and the whitespace characters are
9435 encoded according to RFC1738.
9437 chop: The request is allowed and the URI is chopped at the
9441 NOTE the current Squid implementation of encode and chop violates
9442 RFC2616 by not using a 301 redirect after altering the URL.
9447 LOC: Config.chroot_dir
9450 Specifies a directory where Squid should do a chroot() while
9451 initializing. This also causes Squid to fully drop root
9452 privileges after initializing. This means, for example, if you
9453 use a HTTP port less than 1024 and try to reconfigure, you may
9454 get an error saying that Squid can not open the port.
9457 NAME: balance_on_multiple_ip
9459 LOC: Config.onoff.balance_on_multiple_ip
9462 Modern IP resolvers in squid sort lookup results by preferred access.
9463 By default squid will use these IP in order and only rotates to
9464 the next listed when the most preffered fails.
9466 Some load balancing servers based on round robin DNS have been
9467 found not to preserve user session state across requests
9468 to different IP addresses.
9470 Enabling this directive Squid rotates IP's per request.
9473 NAME: pipeline_prefetch
9474 TYPE: pipelinePrefetch
9475 LOC: Config.pipeline_max_prefetch
9477 DEFAULT_DOC: Do not pre-parse pipelined requests.
9479 HTTP clients may send a pipeline of 1+N requests to Squid using a
9480 single connection, without waiting for Squid to respond to the first
9481 of those requests. This option limits the number of concurrent
9482 requests Squid will try to handle in parallel. If set to N, Squid
9483 will try to receive and process up to 1+N requests on the same
9484 connection concurrently.
9486 Defaults to 0 (off) for bandwidth management and access logging
9489 NOTE: pipelining requires persistent connections to clients.
9491 WARNING: pipelining breaks NTLM and Negotiate/Kerberos authentication.
9494 NAME: high_response_time_warning
9497 LOC: Config.warnings.high_rptm
9499 DEFAULT_DOC: disabled.
9501 If the one-minute median response time exceeds this value,
9502 Squid prints a WARNING with debug level 0 to get the
9503 administrators attention. The value is in milliseconds.
9506 NAME: high_page_fault_warning
9508 LOC: Config.warnings.high_pf
9510 DEFAULT_DOC: disabled.
9512 If the one-minute average page fault rate exceeds this
9513 value, Squid prints a WARNING with debug level 0 to get
9514 the administrators attention. The value is in page faults
9518 NAME: high_memory_warning
9520 LOC: Config.warnings.high_memory
9521 IFDEF: HAVE_MSTATS&&HAVE_GNUMALLOC_H
9523 DEFAULT_DOC: disabled.
9525 If the memory usage (as determined by gnumalloc, if available and used)
9526 exceeds this amount, Squid prints a WARNING with debug level 0 to get
9527 the administrators attention.
9529 # TODO: link high_memory_warning to mempools?
9531 NAME: sleep_after_fork
9532 COMMENT: (microseconds)
9534 LOC: Config.sleep_after_fork
9537 When this is set to a non-zero value, the main Squid process
9538 sleeps the specified number of microseconds after a fork()
9539 system call. This sleep may help the situation where your
9540 system reports fork() failures due to lack of (virtual)
9541 memory. Note, however, if you have a lot of child
9542 processes, these sleep delays will add up and your
9543 Squid will not service requests for some amount of time
9544 until all the child processes have been started.
9545 On Windows value less then 1000 (1 milliseconds) are
9549 NAME: windows_ipaddrchangemonitor
9550 IFDEF: _SQUID_WINDOWS_
9554 LOC: Config.onoff.WIN32_IpAddrChangeMonitor
9556 On Windows Squid by default will monitor IP address changes and will
9557 reconfigure itself after any detected event. This is very useful for
9558 proxies connected to internet with dial-up interfaces.
9559 In some cases (a Proxy server acting as VPN gateway is one) it could be
9560 desiderable to disable this behaviour setting this to 'off'.
9561 Note: after changing this, Squid service must be restarted.
9566 IFDEF: USE_SQUID_EUI
9568 LOC: Eui::TheConfig.euiLookup
9570 Whether to lookup the EUI or MAC address of a connected client.
9573 NAME: max_filedescriptors max_filedesc
9576 DEFAULT_DOC: Use operating system limits set by ulimit.
9577 LOC: Config.max_filedescriptors
9579 Reduce the maximum number of filedescriptors supported below
9580 the usual operating system defaults.
9582 Remove from squid.conf to inherit the current ulimit setting.
9584 Note: Changing this requires a restart of Squid. Also
9585 not all I/O types supports large values (eg on Windows).
9588 NAME: force_request_body_continuation
9590 LOC: Config.accessList.forceRequestBodyContinuation
9592 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
9594 This option controls how Squid handles data upload requests from HTTP
9595 and FTP agents that require a "Please Continue" control message response
9596 to actually send the request body to Squid. It is mostly useful in
9597 adaptation environments.
9599 When Squid receives an HTTP request with an "Expect: 100-continue"
9600 header or an FTP upload command (e.g., STOR), Squid normally sends the
9601 request headers or FTP command information to an adaptation service (or
9602 peer) and waits for a response. Most adaptation services (and some
9603 broken peers) may not respond to Squid at that stage because they may
9604 decide to wait for the HTTP request body or FTP data transfer. However,
9605 that request body or data transfer may never come because Squid has not
9606 responded with the HTTP 100 or FTP 150 (Please Continue) control message
9607 to the request sender yet!
9609 An allow match tells Squid to respond with the HTTP 100 or FTP 150
9610 (Please Continue) control message on its own, before forwarding the
9611 request to an adaptation service or peer. Such a response usually forces
9612 the request sender to proceed with sending the body. A deny match tells
9613 Squid to delay that control response until the origin server confirms
9614 that the request body is needed. Delaying is the default behavior.
projects / thirdparty / squid.git / blob