2 # SQUID Web Proxy Cache http://www.squid-cache.org/
3 # ----------------------------------------------------------
5 # Squid is the result of efforts by numerous individuals from
6 # the Internet community; see the CONTRIBUTORS file for full
7 # details. Many organizations have provided support for Squid's
8 # development; see the SPONSORS file for full details. Squid is
9 # Copyrighted (C) 2000 by the Regents of the University of
10 # California; see the COPYRIGHT file for full details. Squid
11 # incorporates software developed and/or copyrighted by other
12 # sources; see the CREDITS file for full details.
14 # This program is free software; you can redistribute it and/or modify
15 # it under the terms of the GNU General Public License as published by
16 # the Free Software Foundation; either version 2 of the License, or
17 # (at your option) any later version.
19 # This program is distributed in the hope that it will be useful,
20 # but WITHOUT ANY WARRANTY; without even the implied warranty of
21 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 # GNU General Public License for more details.
24 # You should have received a copy of the GNU General Public License
25 # along with this program; if not, write to the Free Software
26 # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
31 ----------------------------
33 This is the documentation for the Squid configuration file.
34 This documentation can also be found online at:
35 http://www.squid-cache.org/Doc/config/
37 You may wish to look at the Squid home page and wiki for the
38 FAQ and other documentation:
39 http://www.squid-cache.org/
40 http://wiki.squid-cache.org/SquidFaq
41 http://wiki.squid-cache.org/ConfigExamples
43 This documentation shows what the defaults for various directives
44 happen to be. If you don't need to change the default, you should
45 leave the line out of your squid.conf in most cases.
47 In some cases "none" refers to no default setting at all,
48 while in other cases it refers to the value of the option
49 - the comments for that keyword indicate if this is the case.
54 Configuration options can be included using the "include" directive.
55 Include takes a list of files to include. Quoting and wildcards are
60 include /path/to/included/file/squid.acl.config
62 Includes can be nested up to a hard-coded depth of 16 levels.
63 This arbitrary restriction is to prevent recursive include references
64 from causing Squid entering an infinite loop whilst trying to load
67 Values with byte units
69 Squid accepts size units on some size related directives. All
70 such directives are documented with a default value displaying
73 Units accepted by Squid are:
75 KB - Kilobyte (1024 bytes)
79 Values with spaces, quotes, and other special characters
81 Squid supports directive parameters with spaces, quotes, and other
82 special characters. Surround such parameters with "double quotes". Use
83 the configuration_includes_quoted_values directive to enable or
86 Squid supports reading configuration option parameters from external
87 files using the syntax:
88 parameters("/path/filename")
90 acl whitelist dstdomain parameters("/etc/squid/whitelist.txt")
92 Conditional configuration
94 If-statements can be used to make configuration directives
98 ... regular configuration directives ...
100 ... regular configuration directives ...]
103 The else part is optional. The keywords "if", "else", and "endif"
104 must be typed on their own lines, as if they were regular
105 configuration directives.
107 NOTE: An else-if condition is not supported.
109 These individual conditions types are supported:
112 Always evaluates to true.
114 Always evaluates to false.
115 <integer> = <integer>
116 Equality comparison of two integer numbers.
121 The following SMP-related preprocessor macros can be used.
123 ${process_name} expands to the current Squid process "name"
124 (e.g., squid1, squid2, or cache1).
126 ${process_number} expands to the current Squid process
127 identifier, which is an integer number (e.g., 1, 2, 3) unique
128 across all Squid processes of the current service instance.
130 ${service_name} expands into the current Squid service instance
131 name identifier which is provided by -n on the command line.
135 # options still not yet ported from 2.7 to 3.x
136 NAME: broken_vary_encoding
139 This option is not yet supported by Squid-3.
145 This option is not yet supported by Squid-3.
151 This option is not yet supported by Squid-3.
154 NAME: external_refresh_check
157 This option is not yet supported by Squid-3.
160 NAME: location_rewrite_program location_rewrite_access location_rewrite_children location_rewrite_concurrency
163 This option is not yet supported by Squid-3.
166 NAME: refresh_stale_hit
169 This option is not yet supported by Squid-3.
172 # Options Removed in 3.3
173 NAME: ignore_ims_on_miss
176 Remove this line. The HTTP/1.1 feature is now fully supported by default.
179 # Options Removed in 3.2
180 NAME: ignore_expect_100
183 Remove this line. The HTTP/1.1 feature is now fully supported by default.
186 NAME: dns_v4_fallback
189 Remove this line. Squid performs a 'Happy Eyeballs' algorithm, the 'fallback' algorithm is no longer relevant.
195 Remove this line. Configure FTP page display using the CSS controls in errorpages.css instead.
198 NAME: maximum_single_addr_tries
201 Replaced by connect_retries. The behaviour has changed, please read the documentation before altering.
207 Remove this line. The feature is supported by default in storage types where update is implemented.
210 NAME: url_rewrite_concurrency
213 Remove this line. Set the 'concurrency=' option of url_rewrite_children instead.
216 # Options Removed in 3.1
220 Remove this line. DNS is no longer tested on startup.
223 NAME: extension_methods
226 Remove this line. All valid methods for HTTP are accepted by default.
229 # 2.7 Options Removed/Replaced in 3.2
234 # 2.7 Options Removed/Replaced in 3.1
242 Remove this line. HTTP/1.1 is supported by default.
245 NAME: upgrade_http0.9
248 Remove this line. ICY/1.0 streaming protocol is supported by default.
251 NAME: zph_local zph_mode zph_option zph_parent zph_sibling
254 Alter these entries. Use the qos_flows directive instead.
257 # Options Removed in 3.0
261 Since squid-3.0 replace with request_header_access or reply_header_access
262 depending on whether you wish to match client requests or server replies.
265 NAME: httpd_accel_no_pmtu_disc
268 Since squid-3.0 use the 'disable-pmtu-discovery' flag on http_port instead.
271 NAME: wais_relay_host
274 Replace this line with 'cache_peer' configuration.
277 NAME: wais_relay_port
280 Replace this line with 'cache_peer' configuration.
284 OPTIONS FOR AUTHENTICATION
285 -----------------------------------------------------------------------------
294 This is used to define parameters for the various authentication
295 schemes supported by Squid.
297 format: auth_param scheme parameter [setting]
299 The order in which authentication schemes are presented to the client is
300 dependent on the order the scheme first appears in config file. IE
301 has a bug (it's not RFC 2617 compliant) in that it will use the basic
302 scheme if basic is the first entry presented, even if more secure
303 schemes are presented. For now use the order in the recommended
304 settings section below. If other browsers have difficulties (don't
305 recognize the schemes offered even if you are using basic) either
306 put basic first, or disable the other schemes (by commenting out their
309 Once an authentication scheme is fully configured, it can only be
310 shutdown by shutting squid down and restarting. Changes can be made on
311 the fly and activated with a reconfigure. I.E. You can change to a
312 different helper, but not unconfigure the helper completely.
314 Please note that while this directive defines how Squid processes
315 authentication it does not automatically activate authentication.
316 To use authentication you must in addition make use of ACLs based
317 on login name in http_access (proxy_auth, proxy_auth_regex or
318 external with %LOGIN used in the format tag). The browser will be
319 challenged for authentication on the first such acl encountered
320 in http_access processing and will also be re-challenged for new
321 login credentials if the request is being denied by a proxy_auth
324 WARNING: authentication can't be used in a transparently intercepting
325 proxy as the client then thinks it is talking to an origin server and
326 not the proxy. This is a limitation of bending the TCP/IP protocol to
327 transparently intercepting port 80, not a limitation in Squid.
328 Ports flagged 'transparent', 'intercept', or 'tproxy' have
329 authentication disabled.
331 === Parameters common to all schemes. ===
334 Specifies the command for the external authenticator. Such a program
335 runs a loop that, on every iteration, reads a request line from
336 the standard and responds with a scheme-specific answer. The loop
337 stops when all input is exchausted (EOF). See scheme-specific
338 "program" descriptions below for details.
341 Specifies a string to be append to request line format for the
342 authentication helper. "Quoted" format values may contain spaces and
343 logformat %macros. In theory, any logformat %macro can be used.
344 In practice, a %macro expands as a dash (-) if the helper request is
345 sent before the required macro information is available to Squid.
346 By default, Squid uses request formats provided in scheme-specific
347 examples below (search for %credentials).
348 The expanded key_extras value is added to the Squid credentials
349 cache and, hence, will affect authentication. It can be used to
350 autenticate different users with identical user names (e.g., when user
351 authentication depends on http_port).
352 Avoid adding frequently changing information to key_extras. For
353 example, if you add user source IP, and it changes frequently
354 in your environment, then max_user_ip ACL is going to treat every
355 user+IP combination as a unique "user", breaking the ACL and
356 wasting a lot of memory on those user records. It will also force
357 users to authenticate from scratch whenever their IP changes.
359 === Parameters for the basic scheme follow. ===
362 Specify the command for the external authenticator. Such a program
363 reads a request_format line ("username password" by default) and
364 replies with one of three results:
370 the user does not exist.
373 An internal error occurred in the helper, preventing
374 a result being identified.
376 "ERR" and "BH" results may optionally be followed by message="..."
377 containing a description available as %m in the returned error page.
379 If you use an authenticator, make sure you have 1 acl of type
382 By default, the basic authentication scheme is not used unless a
383 program is specified.
385 If you want to use the traditional NCSA proxy authentication, set
386 this line to something like
388 auth_param basic program @DEFAULT_PREFIX@/libexec/basic_ncsa_auth @DEFAULT_PREFIX@/etc/passwd
391 HTTP uses iso-latin-1 as character set, while some authentication
392 backends such as LDAP expects UTF-8. If this is set to on Squid will
393 translate the HTTP iso-latin-1 charset to UTF-8 before sending the
394 username & password to the helper.
396 "children" numberofchildren [startup=N] [idle=N] [concurrency=N]
397 The maximum number of authenticator processes to spawn. If you start too few
398 Squid will have to wait for them to process a backlog of credential
399 verifications, slowing it down. When password verifications are
400 done via a (slow) network you are likely to need lots of
401 authenticator processes.
403 The startup= and idle= options permit some skew in the exact amount
404 run. A minimum of startup=N will begin during startup and reconfigure.
405 Squid will start more in groups of up to idle=N in an attempt to meet
406 traffic needs and to keep idle=N free above those traffic needs up to
409 The concurrency= option sets the number of concurrent requests the
410 helper can process. The default of 0 is used for helpers who only
411 supports one request at a time. Setting this to a number greater than
412 0 changes the protocol used to include a channel number first on the
413 request/response line, allowing multiple requests to be sent to the
414 same helper in parallel without waiting for the response.
415 Must not be set unless it's known the helper supports this.
417 auth_param basic children 20 startup=0 idle=1
420 Specifies the realm name which is to be reported to the
421 client for the basic proxy authentication scheme (part of
422 the text the user will see when prompted their username and
423 password). There is no default.
424 auth_param basic realm Squid proxy-caching web server
426 "credentialsttl" timetolive
427 Specifies how long squid assumes an externally validated
428 username:password pair is valid for - in other words how
429 often the helper program is called for that user. Set this
430 low to force revalidation with short lived passwords. Note
431 setting this high does not impact your susceptibility
432 to replay attacks unless you are using an one-time password
433 system (such as SecureID). If you are using such a system,
434 you will be vulnerable to replay attacks unless you also
435 use the max_user_ip ACL in an http_access rule.
437 "casesensitive" on|off
438 Specifies if usernames are case sensitive. Most user databases are
439 case insensitive allowing the same username to be spelled using both
440 lower and upper case letters, but some are case sensitive. This
441 makes a big difference for user_max_ip ACL processing and similar.
442 auth_param basic casesensitive off
444 === Parameters for the digest scheme follow ===
447 Specify the command for the external authenticator. Such a program
448 reads a request_format line ("username":"realm" by default) and
449 replies with one of three results:
452 the user exists. The ha1= key is mandatory and
453 contains the appropriate H(A1) value, hex encoded.
454 See rfc 2616 for the definition of H(A1).
457 the user does not exist.
460 An internal error occurred in the helper, preventing
461 a result being identified.
463 "ERR" and "BH" results may optionally be followed by message="..."
464 containing a description available as %m in the returned error page.
466 By default, the digest authentication scheme is not used unless a
467 program is specified.
469 If you want to use a digest authenticator, set this line to
472 auth_param digest program @DEFAULT_PREFIX@/bin/digest_pw_auth @DEFAULT_PREFIX@/etc/digpass
475 HTTP uses iso-latin-1 as character set, while some authentication
476 backends such as LDAP expects UTF-8. If this is set to on Squid will
477 translate the HTTP iso-latin-1 charset to UTF-8 before sending the
478 username & password to the helper.
480 "children" numberofchildren [startup=N] [idle=N] [concurrency=N]
481 The maximum number of authenticator processes to spawn (default 5).
482 If you start too few Squid will have to wait for them to
483 process a backlog of H(A1) calculations, slowing it down.
484 When the H(A1) calculations are done via a (slow) network
485 you are likely to need lots of authenticator processes.
487 The startup= and idle= options permit some skew in the exact amount
488 run. A minimum of startup=N will begin during startup and reconfigure.
489 Squid will start more in groups of up to idle=N in an attempt to meet
490 traffic needs and to keep idle=N free above those traffic needs up to
493 The concurrency= option sets the number of concurrent requests the
494 helper can process. The default of 0 is used for helpers who only
495 supports one request at a time. Setting this to a number greater than
496 0 changes the protocol used to include a channel number first on the
497 request/response line, allowing multiple requests to be sent to the
498 same helper in parallel without waiting for the response.
499 Must not be set unless it's known the helper supports this.
501 auth_param digest children 20 startup=0 idle=1
504 Specifies the realm name which is to be reported to the
505 client for the digest proxy authentication scheme (part of
506 the text the user will see when prompted their username and
507 password). There is no default.
508 auth_param digest realm Squid proxy-caching web server
510 "nonce_garbage_interval" timeinterval
511 Specifies the interval that nonces that have been issued
512 to client_agent's are checked for validity.
514 "nonce_max_duration" timeinterval
515 Specifies the maximum length of time a given nonce will be
518 "nonce_max_count" number
519 Specifies the maximum number of times a given nonce can be
522 "nonce_strictness" on|off
523 Determines if squid requires strict increment-by-1 behavior
524 for nonce counts, or just incrementing (off - for use when
525 user agents generate nonce counts that occasionally miss 1
526 (ie, 1,2,4,6)). Default off.
528 "check_nonce_count" on|off
529 This directive if set to off can disable the nonce count check
530 completely to work around buggy digest qop implementations in
531 certain mainstream browser versions. Default on to check the
532 nonce count to protect from authentication replay attacks.
534 "post_workaround" on|off
535 This is a workaround to certain buggy browsers who sends
536 an incorrect request digest in POST requests when reusing
537 the same nonce as acquired earlier on a GET request.
539 === NTLM scheme options follow ===
542 Specify the command for the external NTLM authenticator.
543 Such a program reads exchanged NTLMSSP packets with
544 the browser via Squid until authentication is completed.
545 If you use an NTLM authenticator, make sure you have 1 acl
546 of type proxy_auth. By default, the NTLM authenticator program
549 auth_param ntlm program /usr/bin/ntlm_auth
551 "children" numberofchildren [startup=N] [idle=N]
552 The maximum number of authenticator processes to spawn (default 5).
553 If you start too few Squid will have to wait for them to
554 process a backlog of credential verifications, slowing it
555 down. When credential verifications are done via a (slow)
556 network you are likely to need lots of authenticator
559 The startup= and idle= options permit some skew in the exact amount
560 run. A minimum of startup=N will begin during startup and reconfigure.
561 Squid will start more in groups of up to idle=N in an attempt to meet
562 traffic needs and to keep idle=N free above those traffic needs up to
565 auth_param ntlm children 20 startup=0 idle=1
568 If you experience problems with PUT/POST requests when using the
569 Negotiate authentication scheme then you can try setting this to
570 off. This will cause Squid to forcibly close the connection on
571 the initial requests where the browser asks which schemes are
572 supported by the proxy.
574 auth_param ntlm keep_alive on
576 === Options for configuring the NEGOTIATE auth-scheme follow ===
579 Specify the command for the external Negotiate authenticator.
580 This protocol is used in Microsoft Active-Directory enabled setups with
581 the Microsoft Internet Explorer or Mozilla Firefox browsers.
582 Its main purpose is to exchange credentials with the Squid proxy
583 using the Kerberos mechanisms.
584 If you use a Negotiate authenticator, make sure you have at least
585 one acl of type proxy_auth active. By default, the negotiate
586 authenticator program is not used.
587 The only supported program for this role is the ntlm_auth
588 program distributed as part of Samba, version 4 or later.
590 auth_param negotiate program /usr/bin/ntlm_auth --helper-protocol=gss-spnego
592 "children" numberofchildren [startup=N] [idle=N]
593 The maximum number of authenticator processes to spawn (default 5).
594 If you start too few Squid will have to wait for them to
595 process a backlog of credential verifications, slowing it
596 down. When credential verifications are done via a (slow)
597 network you are likely to need lots of authenticator
600 The startup= and idle= options permit some skew in the exact amount
601 run. A minimum of startup=N will begin during startup and reconfigure.
602 Squid will start more in groups of up to idle=N in an attempt to meet
603 traffic needs and to keep idle=N free above those traffic needs up to
606 auth_param negotiate children 20 startup=0 idle=1
609 If you experience problems with PUT/POST requests when using the
610 Negotiate authentication scheme then you can try setting this to
611 off. This will cause Squid to forcibly close the connection on
612 the initial requests where the browser asks which schemes are
613 supported by the proxy.
615 auth_param negotiate keep_alive on
619 #Recommended minimum configuration per scheme:
620 #auth_param negotiate program <uncomment and complete this line to activate>
621 #auth_param negotiate children 20 startup=0 idle=1
622 #auth_param negotiate keep_alive on
624 #auth_param ntlm program <uncomment and complete this line to activate>
625 #auth_param ntlm children 20 startup=0 idle=1
626 #auth_param ntlm keep_alive on
628 #auth_param digest program <uncomment and complete this line>
629 #auth_param digest children 20 startup=0 idle=1
630 #auth_param digest realm Squid proxy-caching web server
631 #auth_param digest nonce_garbage_interval 5 minutes
632 #auth_param digest nonce_max_duration 30 minutes
633 #auth_param digest nonce_max_count 50
635 #auth_param basic program <uncomment and complete this line>
636 #auth_param basic children 5 startup=5 idle=1
637 #auth_param basic realm Squid proxy-caching web server
638 #auth_param basic credentialsttl 2 hours
641 NAME: authenticate_cache_garbage_interval
644 LOC: Config.authenticateGCInterval
646 The time period between garbage collection across the username cache.
647 This is a trade-off between memory utilization (long intervals - say
648 2 days) and CPU (short intervals - say 1 minute). Only change if you
652 NAME: authenticate_ttl
655 LOC: Config.authenticateTTL
657 The time a user & their credentials stay in the logged in
658 user cache since their last request. When the garbage
659 interval passes, all user credentials that have passed their
660 TTL are removed from memory.
663 NAME: authenticate_ip_ttl
665 LOC: Config.authenticateIpTTL
668 If you use proxy authentication and the 'max_user_ip' ACL,
669 this directive controls how long Squid remembers the IP
670 addresses associated with each user. Use a small value
671 (e.g., 60 seconds) if your users might change addresses
672 quickly, as is the case with dialup. You might be safe
673 using a larger value (e.g., 2 hours) in a corporate LAN
674 environment with relatively static address assignments.
679 -----------------------------------------------------------------------------
682 NAME: external_acl_type
683 TYPE: externalAclHelper
684 LOC: Config.externalAclHelperList
687 This option defines external acl classes using a helper program
688 to look up the status
690 external_acl_type name [options] FORMAT.. /path/to/helper [helper arguments..]
694 ttl=n TTL in seconds for cached results (defaults to 3600
697 TTL for cached negative lookups (default same
700 Maximum number of acl helper processes spawned to service
701 external acl lookups of this type. (default 20)
703 Minimum number of acl helper processes to spawn during
704 startup and reconfigure to service external acl lookups
705 of this type. (default 0)
707 Number of acl helper processes to keep ahead of traffic
708 loads. Squid will spawn this many at once whenever load
709 rises above the capabilities of existing processes.
710 Up to the value of children-max. (default 1)
711 concurrency=n concurrency level per process. Only used with helpers
712 capable of processing more than one query at a time.
713 cache=n limit the result cache size, default is unbounded.
714 grace=n Percentage remaining of TTL where a refresh of a
715 cached entry should be initiated without needing to
716 wait for a new reply. (default is for no grace period)
717 protocol=2.5 Compatibility mode for Squid-2.5 external acl helpers
718 ipv4 / ipv6 IP protocol used to communicate with this helper.
719 The default is to auto-detect IPv6 and use it when available.
721 FORMAT specifications
723 %LOGIN Authenticated user login name
724 %EXT_USER Username from previous external acl
725 %EXT_LOG Log details from previous external acl
726 %EXT_TAG Tag from previous external acl
727 %IDENT Ident user name
729 %SRCPORT Client source port
732 %PROTO Requested URL scheme
734 %PATH Requested URL path
735 %METHOD Request method
736 %MYADDR Squid interface address
737 %MYPORT Squid http_port number
738 %PATH Requested URL-path (including query-string if any)
739 %USER_CERT SSL User certificate in PEM format
740 %USER_CERTCHAIN SSL User certificate chain in PEM format
741 %USER_CERT_xx SSL User certificate subject attribute xx
742 %USER_CA_xx SSL User certificate issuer attribute xx
744 %>{Header} HTTP request header "Header"
746 HTTP request header "Hdr" list member "member"
748 HTTP request header list member using ; as
749 list separator. ; can be any non-alphanumeric
752 %<{Header} HTTP reply header "Header"
754 HTTP reply header "Hdr" list member "member"
756 HTTP reply header list member using ; as
757 list separator. ; can be any non-alphanumeric
760 %ACL The name of the ACL being tested.
761 %DATA The ACL arguments. If not used then any arguments
762 is automatically added at the end of the line
764 NOTE: this will encode the arguments as one token,
765 whereas the default will pass each separately.
767 %% The percent sign. Useful for helpers which need
768 an unchanging input format.
771 General request syntax:
773 [channel-ID] FORMAT-values [acl-values ...]
776 FORMAT-values consists of transaction details expanded with
777 whitespace separation per the config file FORMAT specification
778 using the FORMAT macros listed above.
780 acl-values consists of any string specified in the referencing
781 config 'acl ... external' line. see the "acl external" directive.
783 Request values sent to the helper are URL escaped to protect
784 each value in requests against whitespaces.
786 If using protocol=2.5 then the request sent to the helper is not
787 URL escaped to protect against whitespace.
789 NOTE: protocol=3.0 is deprecated as no longer necessary.
791 When using the concurrency= option the protocol is changed by
792 introducing a query channel tag in front of the request/response.
793 The query channel tag is a number between 0 and concurrency-1.
794 This value must be echoed back unchanged to Squid as the first part
795 of the response relating to its request.
798 The helper receives lines expanded per the above format specification
799 and for each input line returns 1 line starting with OK/ERR/BH result
800 code and optionally followed by additional keywords with more details.
803 General result syntax:
805 [channel-ID] result keyword=value ...
807 Result consists of one of the codes:
810 the ACL test produced a match.
813 the ACL test does not produce a match.
816 An internal error occurred in the helper, preventing
817 a result being identified.
819 The meaning of 'a match' is determined by your squid.conf
820 access control configuration. See the Squid wiki for details.
824 user= The users name (login)
826 password= The users password (for login= cache_peer option)
828 message= Message describing the reason for this response.
829 Available as %o in error pages.
830 Useful on (ERR and BH results).
832 tag= Apply a tag to a request. Only sets a tag once,
833 does not alter existing tags.
835 log= String to be logged in access.log. Available as
836 %ea in logformat specifications.
838 Any keywords may be sent on any response whether OK, ERR or BH.
840 All response keyword values need to be a single token with URL
841 escaping, or enclosed in double quotes (") and escaped using \ on
842 any double quotes or \ characters within the value. The wrapping
843 double quotes are removed before the value is interpreted by Squid.
844 \r and \n are also replace by CR and LF.
846 Some example key values:
850 user="J. \"Bob\" Smith"
857 DEFAULT: ssl::certHasExpired ssl_error X509_V_ERR_CERT_HAS_EXPIRED
858 DEFAULT: ssl::certNotYetValid ssl_error X509_V_ERR_CERT_NOT_YET_VALID
859 DEFAULT: ssl::certDomainMismatch ssl_error SQUID_X509_V_ERR_DOMAIN_MISMATCH
860 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
861 DEFAULT: ssl::certSelfSigned ssl_error X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT
864 DEFAULT: manager url_regex -i ^cache_object:// +i ^https?://[^/]+/squid-internal-mgr/
865 DEFAULT: localhost src 127.0.0.1/32 ::1
866 DEFAULT: to_localhost dst 127.0.0.0/8 0.0.0.0/32 ::1
867 DEFAULT_DOC: ACLs all, manager, localhost, and to_localhost are predefined.
869 Defining an Access List
871 Every access list definition must begin with an aclname and acltype,
872 followed by either type-specific arguments or a quoted filename that
875 acl aclname acltype argument ...
876 acl aclname acltype "file" ...
878 When using "file", the file should contain one item per line.
880 Some acl types supports options which changes their default behaviour.
881 The available options are:
883 -i,+i By default, regular expressions are CASE-SENSITIVE. To make them
884 case-insensitive, use the -i option. To return case-sensitive
885 use the +i option between patterns, or make a new ACL line
888 -n Disable lookups and address type conversions. If lookup or
889 conversion is required because the parameter type (IP or
890 domain name) does not match the message address type (domain
891 name or IP), then the ACL would immediately declare a mismatch
892 without any warnings or lookups.
894 -- Used to stop processing all options, in the case the first acl
895 value has '-' character as first character (for example the '-'
896 is a valid domain name)
898 Some acl types require suspending the current request in order
899 to access some external data source.
900 Those which do are marked with the tag [slow], those which
901 don't are marked as [fast].
902 See http://wiki.squid-cache.org/SquidFaq/SquidAcl
903 for further information
905 ***** ACL TYPES AVAILABLE *****
907 acl aclname src ip-address/mask ... # clients IP address [fast]
908 acl aclname src addr1-addr2/mask ... # range of addresses [fast]
909 acl aclname dst [-n] ip-address/mask ... # URL host's IP address [slow]
910 acl aclname localip ip-address/mask ... # IP address the client connected to [fast]
912 acl aclname arp mac-address ... (xx:xx:xx:xx:xx:xx notation)
913 # The arp ACL requires the special configure option --enable-arp-acl.
914 # Furthermore, the ARP ACL code is not portable to all operating systems.
915 # It works on Linux, Solaris, Windows, FreeBSD, and some
916 # other *BSD variants.
919 # NOTE: Squid can only determine the MAC address for clients that are on
920 # the same subnet. If the client is on a different subnet,
921 # then Squid cannot find out its MAC address.
923 acl aclname srcdomain .foo.com ...
924 # reverse lookup, from client IP [slow]
925 acl aclname dstdomain [-n] .foo.com ...
926 # Destination server from URL [fast]
927 acl aclname srcdom_regex [-i] \.foo\.com ...
928 # regex matching client name [slow]
929 acl aclname dstdom_regex [-n] [-i] \.foo\.com ...
930 # regex matching server [fast]
932 # For dstdomain and dstdom_regex a reverse lookup is tried if a IP
933 # based URL is used and no match is found. The name "none" is used
934 # if the reverse lookup fails.
936 acl aclname src_as number ...
937 acl aclname dst_as number ...
939 # Except for access control, AS numbers can be used for
940 # routing of requests to specific caches. Here's an
941 # example for routing all requests for AS#1241 and only
942 # those to mycache.mydomain.net:
943 # acl asexample dst_as 1241
944 # cache_peer_access mycache.mydomain.net allow asexample
945 # cache_peer_access mycache_mydomain.net deny all
947 acl aclname peername myPeer ...
949 # match against a named cache_peer entry
950 # set unique name= on cache_peer lines for reliable use.
952 acl aclname time [day-abbrevs] [h1:m1-h2:m2]
962 # h1:m1 must be less than h2:m2
964 acl aclname url_regex [-i] ^http:// ...
965 # regex matching on whole URL [fast]
966 acl aclname urllogin [-i] [^a-zA-Z0-9] ...
967 # regex matching on URL login field
968 acl aclname urlpath_regex [-i] \.gif$ ...
969 # regex matching on URL path [fast]
971 acl aclname port 80 70 21 0-1024... # destination TCP port [fast]
973 acl aclname localport 3128 ... # TCP port the client connected to [fast]
974 # NP: for interception mode this is usually '80'
976 acl aclname myportname 3128 ... # http(s)_port name [fast]
978 acl aclname proto HTTP FTP ... # request protocol [fast]
980 acl aclname method GET POST ... # HTTP request method [fast]
982 acl aclname http_status 200 301 500- 400-403 ...
983 # status code in reply [fast]
985 acl aclname browser [-i] regexp ...
986 # pattern match on User-Agent header (see also req_header below) [fast]
988 acl aclname referer_regex [-i] regexp ...
989 # pattern match on Referer header [fast]
990 # Referer is highly unreliable, so use with care
992 acl aclname ident username ...
993 acl aclname ident_regex [-i] pattern ...
994 # string match on ident output [slow]
995 # use REQUIRED to accept any non-null ident.
997 acl aclname proxy_auth [-i] username ...
998 acl aclname proxy_auth_regex [-i] pattern ...
999 # perform http authentication challenge to the client and match against
1000 # supplied credentials [slow]
1002 # takes a list of allowed usernames.
1003 # use REQUIRED to accept any valid username.
1005 # Will use proxy authentication in forward-proxy scenarios, and plain
1006 # http authenticaiton in reverse-proxy scenarios
1008 # NOTE: when a Proxy-Authentication header is sent but it is not
1009 # needed during ACL checking the username is NOT logged
1012 # NOTE: proxy_auth requires a EXTERNAL authentication program
1013 # to check username/password combinations (see
1014 # auth_param directive).
1016 # NOTE: proxy_auth can't be used in a transparent/intercepting proxy
1017 # as the browser needs to be configured for using a proxy in order
1018 # to respond to proxy authentication.
1020 acl aclname snmp_community string ...
1021 # A community string to limit access to your SNMP Agent [fast]
1024 # acl snmppublic snmp_community public
1026 acl aclname maxconn number
1027 # This will be matched when the client's IP address has
1028 # more than <number> TCP connections established. [fast]
1029 # NOTE: This only measures direct TCP links so X-Forwarded-For
1030 # indirect clients are not counted.
1032 acl aclname max_user_ip [-s] number
1033 # This will be matched when the user attempts to log in from more
1034 # than <number> different ip addresses. The authenticate_ip_ttl
1035 # parameter controls the timeout on the ip entries. [fast]
1036 # If -s is specified the limit is strict, denying browsing
1037 # from any further IP addresses until the ttl has expired. Without
1038 # -s Squid will just annoy the user by "randomly" denying requests.
1039 # (the counter is reset each time the limit is reached and a
1040 # request is denied)
1041 # NOTE: in acceleration mode or where there is mesh of child proxies,
1042 # clients may appear to come from multiple addresses if they are
1043 # going through proxy farms, so a limit of 1 may cause user problems.
1045 acl aclname random probability
1046 # Pseudo-randomly match requests. Based on the probability given.
1047 # Probability may be written as a decimal (0.333), fraction (1/3)
1048 # or ratio of matches:non-matches (3:5).
1050 acl aclname req_mime_type [-i] mime-type ...
1051 # regex match against the mime type of the request generated
1052 # by the client. Can be used to detect file upload or some
1053 # types HTTP tunneling requests [fast]
1054 # NOTE: This does NOT match the reply. You cannot use this
1055 # to match the returned file type.
1057 acl aclname req_header header-name [-i] any\.regex\.here
1058 # regex match against any of the known request headers. May be
1059 # thought of as a superset of "browser", "referer" and "mime-type"
1062 acl aclname rep_mime_type [-i] mime-type ...
1063 # regex match against the mime type of the reply received by
1064 # squid. Can be used to detect file download or some
1065 # types HTTP tunneling requests. [fast]
1066 # NOTE: This has no effect in http_access rules. It only has
1067 # effect in rules that affect the reply data stream such as
1068 # http_reply_access.
1070 acl aclname rep_header header-name [-i] any\.regex\.here
1071 # regex match against any of the known reply headers. May be
1072 # thought of as a superset of "browser", "referer" and "mime-type"
1075 acl aclname external class_name [arguments...]
1076 # external ACL lookup via a helper class defined by the
1077 # external_acl_type directive [slow]
1079 acl aclname user_cert attribute values...
1080 # match against attributes in a user SSL certificate
1081 # attribute is one of DN/C/O/CN/L/ST [fast]
1083 acl aclname ca_cert attribute values...
1084 # match against attributes a users issuing CA SSL certificate
1085 # attribute is one of DN/C/O/CN/L/ST [fast]
1087 acl aclname ext_user username ...
1088 acl aclname ext_user_regex [-i] pattern ...
1089 # string match on username returned by external acl helper [slow]
1090 # use REQUIRED to accept any non-null user name.
1092 acl aclname tag tagvalue ...
1093 # string match on tag returned by external acl helper [slow]
1095 acl aclname hier_code codename ...
1096 # string match against squid hierarchy code(s); [fast]
1097 # e.g., DIRECT, PARENT_HIT, NONE, etc.
1099 # NOTE: This has no effect in http_access rules. It only has
1100 # effect in rules that affect the reply data stream such as
1101 # http_reply_access.
1103 acl aclname note name [value ...]
1104 # match transaction annotation [fast]
1105 # Without values, matches any annotation with a given name.
1106 # With value(s), matches any annotation with a given name that
1107 # also has one of the given values.
1108 # Names and values are compared using a string equality test.
1109 # Annotation sources include note and adaptation_meta directives
1110 # as well as helper and eCAP responses.
1112 acl aclname adaptation_service service ...
1113 # Matches the name of any icap_service, ecap_service,
1114 # adaptation_service_set, or adaptation_service_chain that Squid
1115 # has used (or attempted to use) for the master transaction.
1116 # This ACL must be defined after the corresponding adaptation
1117 # service is named in squid.conf. This ACL is usable with
1118 # adaptation_meta because it starts matching immediately after
1119 # the service has been selected for adaptation.
1122 acl aclname ssl_error errorname
1123 # match against SSL certificate validation error [fast]
1125 # For valid error names see in @DEFAULT_ERROR_DIR@/templates/error-details.txt
1128 # The following can be used as shortcuts for certificate properties:
1129 # [ssl::]certHasExpired: the "not after" field is in the past
1130 # [ssl::]certNotYetValid: the "not before" field is in the future
1131 # [ssl::]certUntrusted: The certificate issuer is not to be trusted.
1132 # [ssl::]certSelfSigned: The certificate is self signed.
1133 # [ssl::]certDomainMismatch: The certificate CN domain does not
1134 # match the name the name of the host we are connecting to.
1136 # The ssl::certHasExpired, ssl::certNotYetValid, ssl::certDomainMismatch,
1137 # ssl::certUntrusted, and ssl::certSelfSigned can also be used as
1138 # predefined ACLs, just like the 'all' ACL.
1140 # NOTE: The ssl_error ACL is only supported with sslproxy_cert_error,
1141 # sslproxy_cert_sign, and sslproxy_cert_adapt options.
1143 acl aclname server_cert_fingerprint [-sha1] fingerprint
1144 # match against server SSL certificate fingerprint [fast]
1146 # The fingerprint is the digest of the DER encoded version
1147 # of the whole certificate. The user should use the form: XX:XX:...
1148 # Optional argument specifies the digest algorithm to use.
1149 # The SHA1 digest algorithm is the default and is currently
1150 # the only algorithm supported (-sha1).
1152 acl aclname any-of acl1 acl2 ...
1153 # match any one of the acls [fast or slow]
1154 # The first matching ACL stops further ACL evaluation.
1156 # ACLs from multiple any-of lines with the same name are ORed.
1157 # For example, A = (a1 or a2) or (a3 or a4) can be written as
1158 # acl A any-of a1 a2
1159 # acl A any-of a3 a4
1161 # This group ACL is fast if all evaluated ACLs in the group are fast
1162 # and slow otherwise.
1164 acl aclname all-of acl1 acl2 ...
1165 # match all of the acls [fast or slow]
1166 # The first mismatching ACL stops further ACL evaluation.
1168 # ACLs from multiple all-of lines with the same name are ORed.
1169 # For example, B = (b1 and b2) or (b3 and b4) can be written as
1170 # acl B all-of b1 b2
1171 # acl B all-of b3 b4
1173 # This group ACL is fast if all evaluated ACLs in the group are fast
1174 # and slow otherwise.
1177 acl macaddress arp 09:00:2b:23:45:67
1178 acl myexample dst_as 1241
1179 acl password proxy_auth REQUIRED
1180 acl fileupload req_mime_type -i ^multipart/form-data$
1181 acl javascript rep_mime_type -i ^application/x-javascript$
1185 # Recommended minimum configuration:
1188 # Example rule allowing access from your local networks.
1189 # Adapt to list your (internal) IP networks from where browsing
1191 acl localnet src 10.0.0.0/8 # RFC1918 possible internal network
1192 acl localnet src 172.16.0.0/12 # RFC1918 possible internal network
1193 acl localnet src 192.168.0.0/16 # RFC1918 possible internal network
1194 acl localnet src fc00::/7 # RFC 4193 local private network range
1195 acl localnet src fe80::/10 # RFC 4291 link-local (directly plugged) machines
1197 acl SSL_ports port 443
1198 acl Safe_ports port 80 # http
1199 acl Safe_ports port 21 # ftp
1200 acl Safe_ports port 443 # https
1201 acl Safe_ports port 70 # gopher
1202 acl Safe_ports port 210 # wais
1203 acl Safe_ports port 1025-65535 # unregistered ports
1204 acl Safe_ports port 280 # http-mgmt
1205 acl Safe_ports port 488 # gss-http
1206 acl Safe_ports port 591 # filemaker
1207 acl Safe_ports port 777 # multiling http
1208 acl CONNECT method CONNECT
1212 NAME: follow_x_forwarded_for
1214 IFDEF: FOLLOW_X_FORWARDED_FOR
1215 LOC: Config.accessList.followXFF
1216 DEFAULT_IF_NONE: deny all
1217 DEFAULT_DOC: X-Forwarded-For header will be ignored.
1219 Allowing or Denying the X-Forwarded-For header to be followed to
1220 find the original source of a request.
1222 Requests may pass through a chain of several other proxies
1223 before reaching us. The X-Forwarded-For header will contain a
1224 comma-separated list of the IP addresses in the chain, with the
1225 rightmost address being the most recent.
1227 If a request reaches us from a source that is allowed by this
1228 configuration item, then we consult the X-Forwarded-For header
1229 to see where that host received the request from. If the
1230 X-Forwarded-For header contains multiple addresses, we continue
1231 backtracking until we reach an address for which we are not allowed
1232 to follow the X-Forwarded-For header, or until we reach the first
1233 address in the list. For the purpose of ACL used in the
1234 follow_x_forwarded_for directive the src ACL type always matches
1235 the address we are testing and srcdomain matches its rDNS.
1237 The end result of this process is an IP address that we will
1238 refer to as the indirect client address. This address may
1239 be treated as the client address for access control, ICAP, delay
1240 pools and logging, depending on the acl_uses_indirect_client,
1241 icap_uses_indirect_client, delay_pool_uses_indirect_client,
1242 log_uses_indirect_client and tproxy_uses_indirect_client options.
1244 This clause only supports fast acl types.
1245 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1247 SECURITY CONSIDERATIONS:
1249 Any host for which we follow the X-Forwarded-For header
1250 can place incorrect information in the header, and Squid
1251 will use the incorrect information as if it were the
1252 source address of the request. This may enable remote
1253 hosts to bypass any access control restrictions that are
1254 based on the client's source addresses.
1258 acl localhost src 127.0.0.1
1259 acl my_other_proxy srcdomain .proxy.example.com
1260 follow_x_forwarded_for allow localhost
1261 follow_x_forwarded_for allow my_other_proxy
1264 NAME: acl_uses_indirect_client
1267 IFDEF: FOLLOW_X_FORWARDED_FOR
1269 LOC: Config.onoff.acl_uses_indirect_client
1271 Controls whether the indirect client address
1272 (see follow_x_forwarded_for) is used instead of the
1273 direct client address in acl matching.
1275 NOTE: maxconn ACL considers direct TCP links and indirect
1276 clients will always have zero. So no match.
1279 NAME: delay_pool_uses_indirect_client
1282 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_DELAY_POOLS
1284 LOC: Config.onoff.delay_pool_uses_indirect_client
1286 Controls whether the indirect client address
1287 (see follow_x_forwarded_for) is used instead of the
1288 direct client address in delay pools.
1291 NAME: log_uses_indirect_client
1294 IFDEF: FOLLOW_X_FORWARDED_FOR
1296 LOC: Config.onoff.log_uses_indirect_client
1298 Controls whether the indirect client address
1299 (see follow_x_forwarded_for) is used instead of the
1300 direct client address in the access log.
1303 NAME: tproxy_uses_indirect_client
1306 IFDEF: FOLLOW_X_FORWARDED_FOR&&LINUX_NETFILTER
1308 LOC: Config.onoff.tproxy_uses_indirect_client
1310 Controls whether the indirect client address
1311 (see follow_x_forwarded_for) is used instead of the
1312 direct client address when spoofing the outgoing client.
1314 This has no effect on requests arriving in non-tproxy
1317 SECURITY WARNING: Usage of this option is dangerous
1318 and should not be used trivially. Correct configuration
1319 of follow_x_forewarded_for with a limited set of trusted
1320 sources is required to prevent abuse of your proxy.
1323 NAME: spoof_client_ip
1325 LOC: Config.accessList.spoof_client_ip
1327 DEFAULT_DOC: Allow spoofing on all TPROXY traffic.
1329 Control client IP address spoofing of TPROXY traffic based on
1330 defined access lists.
1332 spoof_client_ip allow|deny [!]aclname ...
1334 If there are no "spoof_client_ip" lines present, the default
1335 is to "allow" spoofing of any suitable request.
1337 Note that the cache_peer "no-tproxy" option overrides this ACL.
1339 This clause supports fast acl types.
1340 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1345 LOC: Config.accessList.http
1346 DEFAULT_IF_NONE: deny all
1347 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1349 Allowing or Denying access based on defined access lists
1351 Access to the HTTP port:
1352 http_access allow|deny [!]aclname ...
1354 NOTE on default values:
1356 If there are no "access" lines present, the default is to deny
1359 If none of the "access" lines cause a match, the default is the
1360 opposite of the last line in the list. If the last line was
1361 deny, the default is allow. Conversely, if the last line
1362 is allow, the default will be deny. For these reasons, it is a
1363 good idea to have an "deny all" entry at the end of your access
1364 lists to avoid potential confusion.
1366 This clause supports both fast and slow acl types.
1367 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1372 # Recommended minimum Access Permission configuration:
1374 # Deny requests to certain unsafe ports
1375 http_access deny !Safe_ports
1377 # Deny CONNECT to other than secure SSL ports
1378 http_access deny CONNECT !SSL_ports
1380 # Only allow cachemgr access from localhost
1381 http_access allow localhost manager
1382 http_access deny manager
1384 # We strongly recommend the following be uncommented to protect innocent
1385 # web applications running on the proxy server who think the only
1386 # one who can access services on "localhost" is a local user
1387 #http_access deny to_localhost
1390 # INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS
1393 # Example rule allowing access from your local networks.
1394 # Adapt localnet in the ACL section to list your (internal) IP networks
1395 # from where browsing should be allowed
1396 http_access allow localnet
1397 http_access allow localhost
1399 # And finally deny all other access to this proxy
1400 http_access deny all
1404 NAME: adapted_http_access http_access2
1406 LOC: Config.accessList.adapted_http
1408 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1410 Allowing or Denying access based on defined access lists
1412 Essentially identical to http_access, but runs after redirectors
1413 and ICAP/eCAP adaptation. Allowing access control based on their
1416 If not set then only http_access is used.
1419 NAME: http_reply_access
1421 LOC: Config.accessList.reply
1423 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1425 Allow replies to client requests. This is complementary to http_access.
1427 http_reply_access allow|deny [!] aclname ...
1429 NOTE: if there are no access lines present, the default is to allow
1432 If none of the access lines cause a match the opposite of the
1433 last line will apply. Thus it is good practice to end the rules
1434 with an "allow all" or "deny all" entry.
1436 This clause supports both fast and slow acl types.
1437 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1442 LOC: Config.accessList.icp
1444 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1446 Allowing or Denying access to the ICP port based on defined
1449 icp_access allow|deny [!]aclname ...
1451 NOTE: The default if no icp_access lines are present is to
1452 deny all traffic. This default may cause problems with peers
1455 This clause only supports fast acl types.
1456 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1458 # Allow ICP queries from local networks only
1459 #icp_access allow localnet
1460 #icp_access deny all
1466 LOC: Config.accessList.htcp
1468 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1470 Allowing or Denying access to the HTCP port based on defined
1473 htcp_access allow|deny [!]aclname ...
1475 See also htcp_clr_access for details on access control for
1476 cache purge (CLR) HTCP messages.
1478 NOTE: The default if no htcp_access lines are present is to
1479 deny all traffic. This default may cause problems with peers
1480 using the htcp option.
1482 This clause only supports fast acl types.
1483 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1485 # Allow HTCP queries from local networks only
1486 #htcp_access allow localnet
1487 #htcp_access deny all
1490 NAME: htcp_clr_access
1493 LOC: Config.accessList.htcp_clr
1495 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1497 Allowing or Denying access to purge content using HTCP based
1498 on defined access lists.
1499 See htcp_access for details on general HTCP access control.
1501 htcp_clr_access allow|deny [!]aclname ...
1503 This clause only supports fast acl types.
1504 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1506 # Allow HTCP CLR requests from trusted peers
1507 acl htcp_clr_peer src 192.0.2.2 2001:DB8::2
1508 htcp_clr_access allow htcp_clr_peer
1509 htcp_clr_access deny all
1514 LOC: Config.accessList.miss
1516 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1518 Determins whether network access is permitted when satisfying a request.
1521 to force your neighbors to use you as a sibling instead of
1524 acl localclients src 192.0.2.0/24 2001:DB8::a:0/64
1525 miss_access deny !localclients
1526 miss_access allow all
1528 This means only your local clients are allowed to fetch relayed/MISS
1529 replies from the network and all other clients can only fetch cached
1532 The default for this setting allows all clients who passed the
1533 http_access rules to relay via this proxy.
1535 This clause only supports fast acl types.
1536 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1539 NAME: ident_lookup_access
1543 DEFAULT_DOC: Unless rules exist in squid.conf, IDENT is not fetched.
1544 LOC: Ident::TheConfig.identLookup
1546 A list of ACL elements which, if matched, cause an ident
1547 (RFC 931) lookup to be performed for this request. For
1548 example, you might choose to always perform ident lookups
1549 for your main multi-user Unix boxes, but not for your Macs
1550 and PCs. By default, ident lookups are not performed for
1553 To enable ident lookups for specific client addresses, you
1554 can follow this example:
1556 acl ident_aware_hosts src 198.168.1.0/24
1557 ident_lookup_access allow ident_aware_hosts
1558 ident_lookup_access deny all
1560 Only src type ACL checks are fully supported. A srcdomain
1561 ACL might work at times, but it will not always provide
1564 This clause only supports fast acl types.
1565 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1568 NAME: reply_body_max_size
1569 COMMENT: size [acl acl...]
1572 DEFAULT_DOC: No limit is applied.
1573 LOC: Config.ReplyBodySize
1575 This option specifies the maximum size of a reply body. It can be
1576 used to prevent users from downloading very large files, such as
1577 MP3's and movies. When the reply headers are received, the
1578 reply_body_max_size lines are processed, and the first line where
1579 all (if any) listed ACLs are true is used as the maximum body size
1582 This size is checked twice. First when we get the reply headers,
1583 we check the content-length value. If the content length value exists
1584 and is larger than the allowed size, the request is denied and the
1585 user receives an error message that says "the request or reply
1586 is too large." If there is no content-length, and the reply
1587 size exceeds this limit, the client's connection is just closed
1588 and they will receive a partial reply.
1590 WARNING: downstream caches probably can not detect a partial reply
1591 if there is no content-length header, so they will cache
1592 partial responses and give them out as hits. You should NOT
1593 use this option if you have downstream caches.
1595 WARNING: A maximum size smaller than the size of squid's error messages
1596 will cause an infinite loop and crash squid. Ensure that the smallest
1597 non-zero value you use is greater that the maximum header size plus
1598 the size of your largest error page.
1600 If you set this parameter none (the default), there will be
1603 Configuration Format is:
1604 reply_body_max_size SIZE UNITS [acl ...]
1606 reply_body_max_size 10 MB
1612 -----------------------------------------------------------------------------
1615 NAME: http_port ascii_port
1618 LOC: Config.Sockaddr.http
1620 Usage: port [mode] [options]
1621 hostname:port [mode] [options]
1622 1.2.3.4:port [mode] [options]
1624 The socket addresses where Squid will listen for HTTP client
1625 requests. You may specify multiple socket addresses.
1626 There are three forms: port alone, hostname with port, and
1627 IP address with port. If you specify a hostname or IP
1628 address, Squid binds the socket to that specific
1629 address. Most likely, you do not need to bind to a specific
1630 address, so you can use the port number alone.
1632 If you are running Squid in accelerator mode, you
1633 probably want to listen on port 80 also, or instead.
1635 The -a command line option may be used to specify additional
1636 port(s) where Squid listens for proxy request. Such ports will
1637 be plain proxy ports with no options.
1639 You may specify multiple socket addresses on multiple lines.
1643 intercept Support for IP-Layer interception of
1644 outgoing requests without browser settings.
1645 NP: disables authentication and IPv6 on the port.
1647 tproxy Support Linux TPROXY for spoofing outgoing
1648 connections using the client IP address.
1649 NP: disables authentication and maybe IPv6 on the port.
1651 accel Accelerator / reverse proxy mode
1653 ssl-bump For each CONNECT request allowed by ssl_bump ACLs,
1654 establish secure connection with the client and with
1655 the server, decrypt HTTPS messages as they pass through
1656 Squid, and treat them as unencrypted HTTP messages,
1657 becoming the man-in-the-middle.
1659 The ssl_bump option is required to fully enable
1660 bumping of CONNECT requests.
1662 Omitting the mode flag causes default forward proxy mode to be used.
1665 Accelerator Mode Options:
1667 defaultsite=domainname
1668 What to use for the Host: header if it is not present
1669 in a request. Determines what site (not origin server)
1670 accelerators should consider the default.
1672 no-vhost Disable using HTTP/1.1 Host header for virtual domain support.
1674 protocol= Protocol to reconstruct accelerated and intercepted
1675 requests with. Defaults to HTTP/1.1 for http_port and
1676 HTTPS/1.1 for https_port.
1677 When an unsupported value is configured Squid will
1678 produce a FATAL error.
1679 Values: HTTP or HTTP/1.1, HTTPS or HTTPS/1.1
1681 vport Virtual host port support. Using the http_port number
1682 instead of the port passed on Host: headers.
1684 vport=NN Virtual host port support. Using the specified port
1685 number instead of the port passed on Host: headers.
1688 Act as if this Squid is the origin server.
1689 This currently means generate new Date: and Expires:
1690 headers on HIT instead of adding Age:.
1692 ignore-cc Ignore request Cache-Control headers.
1694 WARNING: This option violates HTTP specifications if
1695 used in non-accelerator setups.
1697 allow-direct Allow direct forwarding in accelerator mode. Normally
1698 accelerated requests are denied direct forwarding as if
1699 never_direct was used.
1701 WARNING: this option opens accelerator mode to security
1702 vulnerabilities usually only affecting in interception
1703 mode. Make sure to protect forwarding with suitable
1704 http_access rules when using this.
1707 SSL Bump Mode Options:
1708 In addition to these options ssl-bump requires TLS/SSL options.
1710 generate-host-certificates[=<on|off>]
1711 Dynamically create SSL server certificates for the
1712 destination hosts of bumped CONNECT requests.When
1713 enabled, the cert and key options are used to sign
1714 generated certificates. Otherwise generated
1715 certificate will be selfsigned.
1716 If there is a CA certificate lifetime of the generated
1717 certificate equals lifetime of the CA certificate. If
1718 generated certificate is selfsigned lifetime is three
1720 This option is enabled by default when ssl-bump is used.
1721 See the ssl-bump option above for more information.
1723 dynamic_cert_mem_cache_size=SIZE
1724 Approximate total RAM size spent on cached generated
1725 certificates. If set to zero, caching is disabled. The
1726 default value is 4MB.
1730 cert= Path to SSL certificate (PEM format).
1732 key= Path to SSL private key file (PEM format)
1733 if not specified, the certificate file is
1734 assumed to be a combined certificate and
1737 version= The version of SSL/TLS supported
1738 1 automatic (default)
1745 cipher= Colon separated list of supported ciphers.
1746 NOTE: some ciphers such as EDH ciphers depend on
1747 additional settings. If those settings are
1748 omitted the ciphers may be silently ignored
1749 by the OpenSSL library.
1751 options= Various SSL implementation options. The most important
1753 NO_SSLv2 Disallow the use of SSLv2
1754 NO_SSLv3 Disallow the use of SSLv3
1755 NO_TLSv1 Disallow the use of TLSv1.0
1756 NO_TLSv1_1 Disallow the use of TLSv1.1
1757 NO_TLSv1_2 Disallow the use of TLSv1.2
1758 SINGLE_DH_USE Always create a new key when using
1759 temporary/ephemeral DH key exchanges
1760 ALL Enable various bug workarounds
1761 suggested as "harmless" by OpenSSL
1762 Be warned that this reduces SSL/TLS
1763 strength to some attacks.
1764 See OpenSSL SSL_CTX_set_options documentation for a
1765 complete list of options.
1767 clientca= File containing the list of CAs to use when
1768 requesting a client certificate.
1770 cafile= File containing additional CA certificates to
1771 use when verifying client certificates. If unset
1772 clientca will be used.
1774 capath= Directory containing additional CA certificates
1775 and CRL lists to use when verifying client certificates.
1777 crlfile= File of additional CRL lists to use when verifying
1778 the client certificate, in addition to CRLs stored in
1779 the capath. Implies VERIFY_CRL flag below.
1781 dhparams= File containing DH parameters for temporary/ephemeral
1782 DH key exchanges. See OpenSSL documentation for details
1783 on how to create this file.
1784 WARNING: EDH ciphers will be silently disabled if this
1787 sslflags= Various flags modifying the use of SSL:
1789 Don't request client certificates
1790 immediately, but wait until acl processing
1791 requires a certificate (not yet implemented).
1793 Don't use the default CA lists built in
1796 Don't allow for session reuse. Each connection
1797 will result in a new SSL session.
1799 Verify CRL lists when accepting client
1802 Verify CRL lists for all certificates in the
1803 client certificate chain.
1805 sslcontext= SSL session ID context identifier.
1809 connection-auth[=on|off]
1810 use connection-auth=off to tell Squid to prevent
1811 forwarding Microsoft connection oriented authentication
1812 (NTLM, Negotiate and Kerberos)
1814 disable-pmtu-discovery=
1815 Control Path-MTU discovery usage:
1816 off lets OS decide on what to do (default).
1817 transparent disable PMTU discovery when transparent
1819 always disable always PMTU discovery.
1821 In many setups of transparently intercepting proxies
1822 Path-MTU discovery can not work on traffic towards the
1823 clients. This is the case when the intercepting device
1824 does not fully track connections and fails to forward
1825 ICMP must fragment messages to the cache server. If you
1826 have such setup and experience that certain clients
1827 sporadically hang or never complete requests set
1828 disable-pmtu-discovery option to 'transparent'.
1830 name= Specifies a internal name for the port. Defaults to
1831 the port specification (port or addr:port)
1833 tcpkeepalive[=idle,interval,timeout]
1834 Enable TCP keepalive probes of idle connections.
1835 In seconds; idle is the initial time before TCP starts
1836 probing the connection, interval how often to probe, and
1837 timeout the time before giving up.
1839 If you run Squid on a dual-homed machine with an internal
1840 and an external interface we recommend you to specify the
1841 internal address:port in http_port. This way Squid will only be
1842 visible on the internal address.
1846 # Squid normally listens to port 3128
1847 http_port @DEFAULT_HTTP_PORT@
1855 LOC: Config.Sockaddr.https
1857 Usage: [ip:]port cert=certificate.pem [key=key.pem] [mode] [options...]
1859 The socket address where Squid will listen for client requests made
1860 over TLS or SSL connections. Commonly referred to as HTTPS.
1862 This is most useful for situations where you are running squid in
1863 accelerator mode and you want to do the SSL work at the accelerator level.
1865 You may specify multiple socket addresses on multiple lines,
1866 each with their own SSL certificate and/or options.
1870 accel Accelerator / reverse proxy mode
1872 intercept Support for IP-Layer interception of
1873 outgoing requests without browser settings.
1874 NP: disables authentication and IPv6 on the port.
1876 tproxy Support Linux TPROXY for spoofing outgoing
1877 connections using the client IP address.
1878 NP: disables authentication and maybe IPv6 on the port.
1880 ssl-bump For each intercepted connection allowed by ssl_bump
1881 ACLs, establish a secure connection with the client and with
1882 the server, decrypt HTTPS messages as they pass through
1883 Squid, and treat them as unencrypted HTTP messages,
1884 becoming the man-in-the-middle.
1886 An "ssl_bump server-first" match is required to
1887 fully enable bumping of intercepted SSL connections.
1889 Requires tproxy or intercept.
1891 Omitting the mode flag causes default forward proxy mode to be used.
1894 See http_port for a list of generic options
1899 cert= Path to SSL certificate (PEM format).
1901 key= Path to SSL private key file (PEM format)
1902 if not specified, the certificate file is
1903 assumed to be a combined certificate and
1906 version= The version of SSL/TLS supported
1907 1 automatic (default)
1912 cipher= Colon separated list of supported ciphers.
1914 options= Various SSL engine options. The most important
1916 NO_SSLv2 Disallow the use of SSLv2
1917 NO_SSLv3 Disallow the use of SSLv3
1918 NO_TLSv1 Disallow the use of TLSv1
1919 SINGLE_DH_USE Always create a new key when using
1920 temporary/ephemeral DH key exchanges
1921 See src/ssl_support.c or OpenSSL SSL_CTX_set_options
1922 documentation for a complete list of options.
1924 clientca= File containing the list of CAs to use when
1925 requesting a client certificate.
1927 cafile= File containing additional CA certificates to
1928 use when verifying client certificates. If unset
1929 clientca will be used.
1931 capath= Directory containing additional CA certificates
1932 and CRL lists to use when verifying client certificates.
1934 crlfile= File of additional CRL lists to use when verifying
1935 the client certificate, in addition to CRLs stored in
1936 the capath. Implies VERIFY_CRL flag below.
1938 dhparams= File containing DH parameters for temporary/ephemeral
1941 sslflags= Various flags modifying the use of SSL:
1943 Don't request client certificates
1944 immediately, but wait until acl processing
1945 requires a certificate (not yet implemented).
1947 Don't use the default CA lists built in
1950 Don't allow for session reuse. Each connection
1951 will result in a new SSL session.
1953 Verify CRL lists when accepting client
1956 Verify CRL lists for all certificates in the
1957 client certificate chain.
1959 sslcontext= SSL session ID context identifier.
1961 generate-host-certificates[=<on|off>]
1962 Dynamically create SSL server certificates for the
1963 destination hosts of bumped SSL requests.When
1964 enabled, the cert and key options are used to sign
1965 generated certificates. Otherwise generated
1966 certificate will be selfsigned.
1967 If there is CA certificate life time of generated
1968 certificate equals lifetime of CA certificate. If
1969 generated certificate is selfsigned lifetime is three
1971 This option is enabled by default when SslBump is used.
1972 See the sslBump option above for more information.
1974 dynamic_cert_mem_cache_size=SIZE
1975 Approximate total RAM size spent on cached generated
1976 certificates. If set to zero, caching is disabled. The
1977 default value is 4MB.
1979 See http_port for a list of available options.
1982 NAME: tcp_outgoing_tos tcp_outgoing_ds tcp_outgoing_dscp
1985 LOC: Ip::Qos::TheConfig.tosToServer
1987 Allows you to select a TOS/Diffserv value for packets outgoing
1988 on the server side, based on an ACL.
1990 tcp_outgoing_tos ds-field [!]aclname ...
1992 Example where normal_service_net uses the TOS value 0x00
1993 and good_service_net uses 0x20
1995 acl normal_service_net src 10.0.0.0/24
1996 acl good_service_net src 10.0.1.0/24
1997 tcp_outgoing_tos 0x00 normal_service_net
1998 tcp_outgoing_tos 0x20 good_service_net
2000 TOS/DSCP values really only have local significance - so you should
2001 know what you're specifying. For more information, see RFC2474,
2002 RFC2475, and RFC3260.
2004 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
2005 "default" to use whatever default your host has. Note that in
2006 practice often only multiples of 4 is usable as the two rightmost bits
2007 have been redefined for use by ECN (RFC 3168 section 23.1).
2009 Processing proceeds in the order specified, and stops at first fully
2013 NAME: clientside_tos
2016 LOC: Ip::Qos::TheConfig.tosToClient
2018 Allows you to select a TOS/Diffserv value for packets being transmitted
2019 on the client-side, based on an ACL.
2021 clientside_tos ds-field [!]aclname ...
2023 Example where normal_service_net uses the TOS value 0x00
2024 and good_service_net uses 0x20
2026 acl normal_service_net src 10.0.0.0/24
2027 acl good_service_net src 10.0.1.0/24
2028 clientside_tos 0x00 normal_service_net
2029 clientside_tos 0x20 good_service_net
2031 Note: This feature is incompatible with qos_flows. Any TOS values set here
2032 will be overwritten by TOS values in qos_flows.
2035 NAME: tcp_outgoing_mark
2037 IFDEF: SO_MARK&&USE_LIBCAP
2039 LOC: Ip::Qos::TheConfig.nfmarkToServer
2041 Allows you to apply a Netfilter mark value to outgoing packets
2042 on the server side, based on an ACL.
2044 tcp_outgoing_mark mark-value [!]aclname ...
2046 Example where normal_service_net uses the mark value 0x00
2047 and good_service_net uses 0x20
2049 acl normal_service_net src 10.0.0.0/24
2050 acl good_service_net src 10.0.1.0/24
2051 tcp_outgoing_mark 0x00 normal_service_net
2052 tcp_outgoing_mark 0x20 good_service_net
2055 NAME: clientside_mark
2057 IFDEF: SO_MARK&&USE_LIBCAP
2059 LOC: Ip::Qos::TheConfig.nfmarkToClient
2061 Allows you to apply a Netfilter mark value to packets being transmitted
2062 on the client-side, based on an ACL.
2064 clientside_mark mark-value [!]aclname ...
2066 Example where normal_service_net uses the mark value 0x00
2067 and good_service_net uses 0x20
2069 acl normal_service_net src 10.0.0.0/24
2070 acl good_service_net src 10.0.1.0/24
2071 clientside_mark 0x00 normal_service_net
2072 clientside_mark 0x20 good_service_net
2074 Note: This feature is incompatible with qos_flows. Any mark values set here
2075 will be overwritten by mark values in qos_flows.
2082 LOC: Ip::Qos::TheConfig
2084 Allows you to select a TOS/DSCP value to mark outgoing
2085 connections to the client, based on where the reply was sourced.
2086 For platforms using netfilter, allows you to set a netfilter mark
2087 value instead of, or in addition to, a TOS value.
2089 By default this functionality is disabled. To enable it with the default
2090 settings simply use "qos_flows mark" or "qos_flows tos". Default
2091 settings will result in the netfilter mark or TOS value being copied
2092 from the upstream connection to the client. Note that it is the connection
2093 CONNMARK value not the packet MARK value that is copied.
2095 It is not currently possible to copy the mark or TOS value from the
2096 client to the upstream connection request.
2098 TOS values really only have local significance - so you should
2099 know what you're specifying. For more information, see RFC2474,
2100 RFC2475, and RFC3260.
2102 The TOS/DSCP byte must be exactly that - a octet value 0 - 255. Note that
2103 in practice often only multiples of 4 is usable as the two rightmost bits
2104 have been redefined for use by ECN (RFC 3168 section 23.1).
2106 Mark values can be any unsigned 32-bit integer value.
2108 This setting is configured by setting the following values:
2110 tos|mark Whether to set TOS or netfilter mark values
2112 local-hit=0xFF Value to mark local cache hits.
2114 sibling-hit=0xFF Value to mark hits from sibling peers.
2116 parent-hit=0xFF Value to mark hits from parent peers.
2118 miss=0xFF[/mask] Value to mark cache misses. Takes precedence
2119 over the preserve-miss feature (see below), unless
2120 mask is specified, in which case only the bits
2121 specified in the mask are written.
2123 The TOS variant of the following features are only possible on Linux
2124 and require your kernel to be patched with the TOS preserving ZPH
2125 patch, available from http://zph.bratcheda.org
2126 No patch is needed to preserve the netfilter mark, which will work
2127 with all variants of netfilter.
2129 disable-preserve-miss
2130 This option disables the preservation of the TOS or netfilter
2131 mark. By default, the existing TOS or netfilter mark value of
2132 the response coming from the remote server will be retained
2133 and masked with miss-mark.
2134 NOTE: in the case of a netfilter mark, the mark must be set on
2135 the connection (using the CONNMARK target) not on the packet
2139 Allows you to mask certain bits in the TOS or mark value
2140 received from the remote server, before copying the value to
2141 the TOS sent towards clients.
2142 Default for tos: 0xFF (TOS from server is not changed).
2143 Default for mark: 0xFFFFFFFF (mark from server is not changed).
2145 All of these features require the --enable-zph-qos compilation flag
2146 (enabled by default). Netfilter marking also requires the
2147 libnetfilter_conntrack libraries (--with-netfilter-conntrack) and
2148 libcap 2.09+ (--with-libcap).
2152 NAME: tcp_outgoing_address
2155 DEFAULT_DOC: Address selection is performed by the operating system.
2156 LOC: Config.accessList.outgoing_address
2158 Allows you to map requests to different outgoing IP addresses
2159 based on the username or source address of the user making
2162 tcp_outgoing_address ipaddr [[!]aclname] ...
2165 Forwarding clients with dedicated IPs for certain subnets.
2167 acl normal_service_net src 10.0.0.0/24
2168 acl good_service_net src 10.0.2.0/24
2170 tcp_outgoing_address 2001:db8::c001 good_service_net
2171 tcp_outgoing_address 10.1.0.2 good_service_net
2173 tcp_outgoing_address 2001:db8::beef normal_service_net
2174 tcp_outgoing_address 10.1.0.1 normal_service_net
2176 tcp_outgoing_address 2001:db8::1
2177 tcp_outgoing_address 10.1.0.3
2179 Processing proceeds in the order specified, and stops at first fully
2182 Squid will add an implicit IP version test to each line.
2183 Requests going to IPv4 websites will use the outgoing 10.1.0.* addresses.
2184 Requests going to IPv6 websites will use the outgoing 2001:db8:* addresses.
2187 NOTE: The use of this directive using client dependent ACLs is
2188 incompatible with the use of server side persistent connections. To
2189 ensure correct results it is best to set server_persistent_connections
2190 to off when using this directive in such configurations.
2192 NOTE: The use of this directive to set a local IP on outgoing TCP links
2193 is incompatible with using TPROXY to set client IP out outbound TCP links.
2194 When needing to contact peers use the no-tproxy cache_peer option and the
2195 client_dst_passthru directive re-enable normal forwarding such as this.
2199 NAME: host_verify_strict
2202 LOC: Config.onoff.hostStrictVerify
2204 Regardless of this option setting, when dealing with intercepted
2205 traffic, Squid always verifies that the destination IP address matches
2206 the Host header domain or IP (called 'authority form URL').
2208 This enforcement is performed to satisfy a MUST-level requirement in
2209 RFC 2616 section 14.23: "The Host field value MUST represent the naming
2210 authority of the origin server or gateway given by the original URL".
2213 Squid always responds with an HTTP 409 (Conflict) error
2214 page and logs a security warning if there is no match.
2216 Squid verifies that the destination IP address matches
2217 the Host header for forward-proxy and reverse-proxy traffic
2218 as well. For those traffic types, Squid also enables the
2219 following checks, comparing the corresponding Host header
2220 and Request-URI components:
2222 * The host names (domain or IP) must be identical,
2223 but valueless or missing Host header disables all checks.
2224 For the two host names to match, both must be either IP
2227 * Port numbers must be identical, but if a port is missing
2228 the scheme-default port is assumed.
2231 When set to OFF (the default):
2232 Squid allows suspicious requests to continue but logs a
2233 security warning and blocks caching of the response.
2235 * Forward-proxy traffic is not checked at all.
2237 * Reverse-proxy traffic is not checked at all.
2239 * Intercepted traffic which passes verification is handled
2240 according to client_dst_passthru.
2242 * Intercepted requests which fail verification are sent
2243 to the client original destination instead of DIRECT.
2244 This overrides 'client_dst_passthru off'.
2246 For now suspicious intercepted CONNECT requests are always
2247 responded to with an HTTP 409 (Conflict) error page.
2252 As described in CVE-2009-0801 when the Host: header alone is used
2253 to determine the destination of a request it becomes trivial for
2254 malicious scripts on remote websites to bypass browser same-origin
2255 security policy and sandboxing protections.
2257 The cause of this is that such applets are allowed to perform their
2258 own HTTP stack, in which case the same-origin policy of the browser
2259 sandbox only verifies that the applet tries to contact the same IP
2260 as from where it was loaded at the IP level. The Host: header may
2261 be different from the connected IP and approved origin.
2265 NAME: client_dst_passthru
2268 LOC: Config.onoff.client_dst_passthru
2270 With NAT or TPROXY intercepted traffic Squid may pass the request
2271 directly to the original client destination IP or seek a faster
2272 source using the HTTP Host header.
2274 Using Host to locate alternative servers can provide faster
2275 connectivity with a range of failure recovery options.
2276 But can also lead to connectivity trouble when the client and
2277 server are attempting stateful interactions unaware of the proxy.
2279 This option (on by default) prevents alternative DNS entries being
2280 located to send intercepted traffic DIRECT to an origin server.
2281 The clients original destination IP and port will be used instead.
2283 Regardless of this option setting, when dealing with intercepted
2284 traffic Squid will verify the Host: header and any traffic which
2285 fails Host verification will be treated as if this option were ON.
2287 see host_verify_strict for details on the verification process.
2292 -----------------------------------------------------------------------------
2295 NAME: ssl_unclean_shutdown
2299 LOC: Config.SSL.unclean_shutdown
2301 Some browsers (especially MSIE) bugs out on SSL shutdown
2308 LOC: Config.SSL.ssl_engine
2311 The OpenSSL engine to use. You will need to set this if you
2312 would like to use hardware SSL acceleration for example.
2315 NAME: sslproxy_client_certificate
2318 LOC: Config.ssl_client.cert
2321 Client SSL Certificate to use when proxying https:// URLs
2324 NAME: sslproxy_client_key
2327 LOC: Config.ssl_client.key
2330 Client SSL Key to use when proxying https:// URLs
2333 NAME: sslproxy_version
2336 DEFAULT_DOC: automatic SSL/TLS version negotiation
2337 LOC: Config.ssl_client.version
2340 SSL version level to use when proxying https:// URLs
2342 The versions of SSL/TLS supported:
2344 1 automatic (default)
2352 NAME: sslproxy_options
2355 LOC: Config.ssl_client.options
2358 SSL implementation options to use when proxying https:// URLs
2360 The most important being:
2362 NO_SSLv2 Disallow the use of SSLv2
2363 NO_SSLv3 Disallow the use of SSLv3
2364 NO_TLSv1 Disallow the use of TLSv1.0
2365 NO_TLSv1_1 Disallow the use of TLSv1.1
2366 NO_TLSv1_2 Disallow the use of TLSv1.2
2368 Always create a new key when using temporary/ephemeral
2371 Disable use of RFC5077 session tickets. Some servers
2372 may have problems understanding the TLS extension due
2373 to ambiguous specification in RFC4507.
2374 ALL Enable various bug workarounds suggested as "harmless"
2375 by OpenSSL. Be warned that this may reduce SSL/TLS
2376 strength to some attacks.
2378 See the OpenSSL SSL_CTX_set_options documentation for a
2379 complete list of possible options.
2382 NAME: sslproxy_cipher
2385 LOC: Config.ssl_client.cipher
2388 SSL cipher list to use when proxying https:// URLs
2390 Colon separated list of supported ciphers.
2393 NAME: sslproxy_cafile
2396 LOC: Config.ssl_client.cafile
2399 file containing CA certificates to use when verifying server
2400 certificates while proxying https:// URLs
2403 NAME: sslproxy_capath
2406 LOC: Config.ssl_client.capath
2409 directory containing CA certificates to use when verifying
2410 server certificates while proxying https:// URLs
2413 NAME: sslproxy_session_ttl
2416 LOC: Config.SSL.session_ttl
2419 Sets the timeout value for SSL sessions
2422 NAME: sslproxy_session_cache_size
2425 LOC: Config.SSL.sessionCacheSize
2428 Sets the cache size to use for ssl session
2433 TYPE: sslproxy_ssl_bump
2434 LOC: Config.accessList.ssl_bump
2435 DEFAULT_DOC: Does not bump unless rules are present in squid.conf
2438 This option is consulted when a CONNECT request is received on
2439 an http_port (or a new connection is intercepted at an
2440 https_port), provided that port was configured with an ssl-bump
2441 flag. The subsequent data on the connection is either treated as
2442 HTTPS and decrypted OR tunneled at TCP level without decryption,
2443 depending on the first bumping "mode" which ACLs match.
2445 ssl_bump <mode> [!]acl ...
2447 The following bumping modes are supported:
2450 Allow bumping of the connection. Establish a secure connection
2451 with the client first, then connect to the server. This old mode
2452 does not allow Squid to mimic server SSL certificate and does
2453 not work with intercepted SSL connections.
2456 Allow bumping of the connection. Establish a secure connection
2457 with the server first, then establish a secure connection with
2458 the client, using a mimicked server certificate. Works with both
2459 CONNECT requests and intercepted SSL connections.
2462 Decides if the connection should bumped or not based on
2463 client-to-squid and server-to-squid SSL hello messages.
2466 Become a TCP tunnel without decoding the connection.
2467 Works with both CONNECT requests and intercepted SSL
2468 connections. This is the default behavior when no
2469 ssl_bump option is given or no ssl_bump ACLs match.
2471 By default, no connections are bumped.
2473 The first matching ssl_bump option wins. If no ACLs match, the
2474 connection is not bumped. Unlike most allow/deny ACL lists, ssl_bump
2475 does not have an implicit "negate the last given option" rule. You
2476 must make that rule explicit if you convert old ssl_bump allow/deny
2477 rules that rely on such an implicit rule.
2479 This clause supports both fast and slow acl types.
2480 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2482 See also: http_port ssl-bump, https_port ssl-bump
2485 # Example: Bump all requests except those originating from
2486 # localhost or those going to example.com.
2488 acl broken_sites dstdomain .example.com
2489 ssl_bump none localhost
2490 ssl_bump none broken_sites
2491 ssl_bump server-first all
2494 NAME: ssl_bump_peeked
2496 TYPE: sslproxy_ssl_bump_peeked
2497 LOC: Config.accessList.ssl_bump_peeked
2500 This option used to control splicing decision after we peek at the
2503 ssl_bump_peeked <mode> [!]acl ...
2505 The following peeked modes are supported:
2508 Allow bumping the connection
2511 Do not bump the connection if possible.
2513 ssl_bump_peeked server-first safeToBump
2514 ssl_bump_peeked splice all
2517 NAME: sslproxy_flags
2520 LOC: Config.ssl_client.flags
2523 Various flags modifying the use of SSL while proxying https:// URLs:
2524 DONT_VERIFY_PEER Accept certificates that fail verification.
2525 For refined control, see sslproxy_cert_error.
2526 NO_DEFAULT_CA Don't use the default CA list built in
2530 NAME: sslproxy_cert_error
2533 DEFAULT_DOC: Server certificate errors terminate the transaction.
2534 LOC: Config.ssl_client.cert_error
2537 Use this ACL to bypass server certificate validation errors.
2539 For example, the following lines will bypass all validation errors
2540 when talking to servers for example.com. All other
2541 validation errors will result in ERR_SECURE_CONNECT_FAIL error.
2543 acl BrokenButTrustedServers dstdomain example.com
2544 sslproxy_cert_error allow BrokenButTrustedServers
2545 sslproxy_cert_error deny all
2547 This clause only supports fast acl types.
2548 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2549 Using slow acl types may result in server crashes
2551 Without this option, all server certificate validation errors
2552 terminate the transaction to protect Squid and the client.
2554 SQUID_X509_V_ERR_INFINITE_VALIDATION error cannot be bypassed
2555 but should not happen unless your OpenSSL library is buggy.
2558 Bypassing validation errors is dangerous because an
2559 error usually implies that the server cannot be trusted
2560 and the connection may be insecure.
2562 See also: sslproxy_flags and DONT_VERIFY_PEER.
2565 NAME: sslproxy_cert_sign
2568 POSTSCRIPTUM: signUntrusted ssl::certUntrusted
2569 POSTSCRIPTUM: signSelf ssl::certSelfSigned
2570 POSTSCRIPTUM: signTrusted all
2571 TYPE: sslproxy_cert_sign
2572 LOC: Config.ssl_client.cert_sign
2575 sslproxy_cert_sign <signing algorithm> acl ...
2577 The following certificate signing algorithms are supported:
2580 Sign using the configured CA certificate which is usually
2581 placed in and trusted by end-user browsers. This is the
2582 default for trusted origin server certificates.
2585 Sign to guarantee an X509_V_ERR_CERT_UNTRUSTED browser error.
2586 This is the default for untrusted origin server certificates
2587 that are not self-signed (see ssl::certUntrusted).
2590 Sign using a self-signed certificate with the right CN to
2591 generate a X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT error in the
2592 browser. This is the default for self-signed origin server
2593 certificates (see ssl::certSelfSigned).
2595 This clause only supports fast acl types.
2597 When sslproxy_cert_sign acl(s) match, Squid uses the corresponding
2598 signing algorithm to generate the certificate and ignores all
2599 subsequent sslproxy_cert_sign options (the first match wins). If no
2600 acl(s) match, the default signing algorithm is determined by errors
2601 detected when obtaining and validating the origin server certificate.
2603 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2604 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2605 CONNECT request that carries a domain name. In all other cases (CONNECT
2606 to an IP address or an intercepted SSL connection), Squid cannot detect
2607 the domain mismatch at certificate generation time when
2608 bump-server-first is used.
2611 NAME: sslproxy_cert_adapt
2614 TYPE: sslproxy_cert_adapt
2615 LOC: Config.ssl_client.cert_adapt
2618 sslproxy_cert_adapt <adaptation algorithm> acl ...
2620 The following certificate adaptation algorithms are supported:
2623 Sets the "Not After" property to the "Not After" property of
2624 the CA certificate used to sign generated certificates.
2627 Sets the "Not Before" property to the "Not Before" property of
2628 the CA certificate used to sign generated certificates.
2630 setCommonName or setCommonName{CN}
2631 Sets Subject.CN property to the host name specified as a
2632 CN parameter or, if no explicit CN parameter was specified,
2633 extracted from the CONNECT request. It is a misconfiguration
2634 to use setCommonName without an explicit parameter for
2635 intercepted or tproxied SSL connections.
2637 This clause only supports fast acl types.
2639 Squid first groups sslproxy_cert_adapt options by adaptation algorithm.
2640 Within a group, when sslproxy_cert_adapt acl(s) match, Squid uses the
2641 corresponding adaptation algorithm to generate the certificate and
2642 ignores all subsequent sslproxy_cert_adapt options in that algorithm's
2643 group (i.e., the first match wins within each algorithm group). If no
2644 acl(s) match, the default mimicking action takes place.
2646 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2647 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2648 CONNECT request that carries a domain name. In all other cases (CONNECT
2649 to an IP address or an intercepted SSL connection), Squid cannot detect
2650 the domain mismatch at certificate generation time when
2651 bump-server-first is used.
2654 NAME: sslpassword_program
2657 LOC: Config.Program.ssl_password
2660 Specify a program used for entering SSL key passphrases
2661 when using encrypted SSL certificate keys. If not specified
2662 keys must either be unencrypted, or Squid started with the -N
2663 option to allow it to query interactively for the passphrase.
2665 The key file name is given as argument to the program allowing
2666 selection of the right password if you have multiple encrypted
2671 OPTIONS RELATING TO EXTERNAL SSL_CRTD
2672 -----------------------------------------------------------------------------
2675 NAME: sslcrtd_program
2678 DEFAULT: @DEFAULT_SSL_CRTD@ -s @DEFAULT_SSL_DB_DIR@ -M 4MB
2679 LOC: Ssl::TheConfig.ssl_crtd
2681 Specify the location and options of the executable for ssl_crtd process.
2682 @DEFAULT_SSL_CRTD@ program requires -s and -M parameters
2683 For more information use:
2684 @DEFAULT_SSL_CRTD@ -h
2687 NAME: sslcrtd_children
2688 TYPE: HelperChildConfig
2690 DEFAULT: 32 startup=5 idle=1
2691 LOC: Ssl::TheConfig.ssl_crtdChildren
2693 The maximum number of processes spawn to service ssl server.
2694 The maximum this may be safely set to is 32.
2696 The startup= and idle= options allow some measure of skew in your
2701 Sets the minimum number of processes to spawn when Squid
2702 starts or reconfigures. When set to zero the first request will
2703 cause spawning of the first child process to handle it.
2705 Starting too few children temporary slows Squid under load while it
2706 tries to spawn enough additional processes to cope with traffic.
2710 Sets a minimum of how many processes Squid is to try and keep available
2711 at all times. When traffic begins to rise above what the existing
2712 processes can handle this many more will be spawned up to the maximum
2713 configured. A minimum setting of 1 is required.
2715 You must have at least one ssl_crtd process.
2718 NAME: sslcrtvalidator_program
2722 LOC: Ssl::TheConfig.ssl_crt_validator
2724 Specify the location and options of the executable for ssl_crt_validator
2727 Usage: sslcrtvalidator_program [ttl=n] [cache=n] path ...
2730 ttl=n TTL in seconds for cached results. The default is 60 secs
2731 cache=n limit the result cache size. The default value is 2048
2734 NAME: sslcrtvalidator_children
2735 TYPE: HelperChildConfig
2737 DEFAULT: 32 startup=5 idle=1 concurrency=1
2738 LOC: Ssl::TheConfig.ssl_crt_validator_Children
2740 The maximum number of processes spawn to service SSL server.
2741 The maximum this may be safely set to is 32.
2743 The startup= and idle= options allow some measure of skew in your
2748 Sets the minimum number of processes to spawn when Squid
2749 starts or reconfigures. When set to zero the first request will
2750 cause spawning of the first child process to handle it.
2752 Starting too few children temporary slows Squid under load while it
2753 tries to spawn enough additional processes to cope with traffic.
2757 Sets a minimum of how many processes Squid is to try and keep available
2758 at all times. When traffic begins to rise above what the existing
2759 processes can handle this many more will be spawned up to the maximum
2760 configured. A minimum setting of 1 is required.
2764 The number of requests each certificate validator helper can handle in
2765 parallel. A value of 0 indicates the certficate validator does not
2766 support concurrency. Defaults to 1.
2768 When this directive is set to a value >= 1 then the protocol
2769 used to communicate with the helper is modified to include
2770 a request ID in front of the request/response. The request
2771 ID from the request must be echoed back with the response
2774 You must have at least one ssl_crt_validator process.
2778 OPTIONS WHICH AFFECT THE NEIGHBOR SELECTION ALGORITHM
2779 -----------------------------------------------------------------------------
2787 To specify other caches in a hierarchy, use the format:
2789 cache_peer hostname type http-port icp-port [options]
2794 # hostname type port port options
2795 # -------------------- -------- ----- ----- -----------
2796 cache_peer parent.foo.net parent 3128 3130 default
2797 cache_peer sib1.foo.net sibling 3128 3130 proxy-only
2798 cache_peer sib2.foo.net sibling 3128 3130 proxy-only
2799 cache_peer example.com parent 80 0 default
2800 cache_peer cdn.example.com sibling 3128 0
2802 type: either 'parent', 'sibling', or 'multicast'.
2804 proxy-port: The port number where the peer accept HTTP requests.
2805 For other Squid proxies this is usually 3128
2806 For web servers this is usually 80
2808 icp-port: Used for querying neighbor caches about objects.
2809 Set to 0 if the peer does not support ICP or HTCP.
2810 See ICP and HTCP options below for additional details.
2813 ==== ICP OPTIONS ====
2815 You MUST also set icp_port and icp_access explicitly when using these options.
2816 The defaults will prevent peer traffic using ICP.
2819 no-query Disable ICP queries to this neighbor.
2822 Indicates the named peer is a member of a multicast group.
2823 ICP queries will not be sent directly to the peer, but ICP
2824 replies will be accepted from it.
2826 closest-only Indicates that, for ICP_OP_MISS replies, we'll only forward
2827 CLOSEST_PARENT_MISSes and never FIRST_PARENT_MISSes.
2830 To only send ICP queries to this neighbor infrequently.
2831 This is used to keep the neighbor round trip time updated
2832 and is usually used in conjunction with weighted-round-robin.
2835 ==== HTCP OPTIONS ====
2837 You MUST also set htcp_port and htcp_access explicitly when using these options.
2838 The defaults will prevent peer traffic using HTCP.
2841 htcp Send HTCP, instead of ICP, queries to the neighbor.
2842 You probably also want to set the "icp-port" to 4827
2843 instead of 3130. This directive accepts a comma separated
2844 list of options described below.
2846 htcp=oldsquid Send HTCP to old Squid versions (2.5 or earlier).
2848 htcp=no-clr Send HTCP to the neighbor but without
2849 sending any CLR requests. This cannot be used with
2852 htcp=only-clr Send HTCP to the neighbor but ONLY CLR requests.
2853 This cannot be used with no-clr.
2856 Send HTCP to the neighbor including CLRs but only when
2857 they do not result from PURGE requests.
2860 Forward any HTCP CLR requests this proxy receives to the peer.
2863 ==== PEER SELECTION METHODS ====
2865 The default peer selection method is ICP, with the first responding peer
2866 being used as source. These options can be used for better load balancing.
2869 default This is a parent cache which can be used as a "last-resort"
2870 if a peer cannot be located by any of the peer-selection methods.
2871 If specified more than once, only the first is used.
2873 round-robin Load-Balance parents which should be used in a round-robin
2874 fashion in the absence of any ICP queries.
2875 weight=N can be used to add bias.
2877 weighted-round-robin
2878 Load-Balance parents which should be used in a round-robin
2879 fashion with the frequency of each parent being based on the
2880 round trip time. Closer parents are used more often.
2881 Usually used for background-ping parents.
2882 weight=N can be used to add bias.
2884 carp Load-Balance parents which should be used as a CARP array.
2885 The requests will be distributed among the parents based on the
2886 CARP load balancing hash function based on their weight.
2888 userhash Load-balance parents based on the client proxy_auth or ident username.
2890 sourcehash Load-balance parents based on the client source IP.
2893 To be used only for cache peers of type "multicast".
2894 ALL members of this multicast group have "sibling"
2895 relationship with it, not "parent". This is to a multicast
2896 group when the requested object would be fetched only from
2897 a "parent" cache, anyway. It's useful, e.g., when
2898 configuring a pool of redundant Squid proxies, being
2899 members of the same multicast group.
2902 ==== PEER SELECTION OPTIONS ====
2904 weight=N use to affect the selection of a peer during any weighted
2905 peer-selection mechanisms.
2906 The weight must be an integer; default is 1,
2907 larger weights are favored more.
2908 This option does not affect parent selection if a peering
2909 protocol is not in use.
2911 basetime=N Specify a base amount to be subtracted from round trip
2913 It is subtracted before division by weight in calculating
2914 which parent to fectch from. If the rtt is less than the
2915 base time the rtt is set to a minimal value.
2917 ttl=N Specify a TTL to use when sending multicast ICP queries
2919 Only useful when sending to a multicast group.
2920 Because we don't accept ICP replies from random
2921 hosts, you must configure other group members as
2922 peers with the 'multicast-responder' option.
2924 no-delay To prevent access to this neighbor from influencing the
2927 digest-url=URL Tell Squid to fetch the cache digest (if digests are
2928 enabled) for this host from the specified URL rather
2929 than the Squid default location.
2932 ==== CARP OPTIONS ====
2934 carp-key=key-specification
2935 use a different key than the full URL to hash against the peer.
2936 the key-specification is a comma-separated list of the keywords
2937 scheme, host, port, path, params
2938 Order is not important.
2940 ==== ACCELERATOR / REVERSE-PROXY OPTIONS ====
2942 originserver Causes this parent to be contacted as an origin server.
2943 Meant to be used in accelerator setups when the peer
2947 Set the Host header of requests forwarded to this peer.
2948 Useful in accelerator setups where the server (peer)
2949 expects a certain domain name but clients may request
2950 others. ie example.com or www.example.com
2952 no-digest Disable request of cache digests.
2955 Disables requesting ICMP RTT database (NetDB).
2958 ==== AUTHENTICATION OPTIONS ====
2961 If this is a personal/workgroup proxy and your parent
2962 requires proxy authentication.
2964 Note: The string can include URL escapes (i.e. %20 for
2965 spaces). This also means % must be written as %%.
2968 Send login details received from client to this peer.
2969 Both Proxy- and WWW-Authorization headers are passed
2970 without alteration to the peer.
2971 Authentication is not required by Squid for this to work.
2973 Note: This will pass any form of authentication but
2974 only Basic auth will work through a proxy unless the
2975 connection-auth options are also used.
2977 login=PASS Send login details received from client to this peer.
2978 Authentication is not required by this option.
2980 If there are no client-provided authentication headers
2981 to pass on, but username and password are available
2982 from an external ACL user= and password= result tags
2983 they may be sent instead.
2985 Note: To combine this with proxy_auth both proxies must
2986 share the same user database as HTTP only allows for
2987 a single login (one for proxy, one for origin server).
2988 Also be warned this will expose your users proxy
2989 password to the peer. USE WITH CAUTION
2992 Send the username to the upstream cache, but with a
2993 fixed password. This is meant to be used when the peer
2994 is in another administrative domain, but it is still
2995 needed to identify each user.
2996 The star can optionally be followed by some extra
2997 information which is added to the username. This can
2998 be used to identify this proxy to the peer, similar to
2999 the login=username:password option above.
3002 If this is a personal/workgroup proxy and your parent
3003 requires a secure proxy authentication.
3004 The first principal from the default keytab or defined by
3005 the environment variable KRB5_KTNAME will be used.
3007 WARNING: The connection may transmit requests from multiple
3008 clients. Negotiate often assumes end-to-end authentication
3009 and a single-client. Which is not strictly true here.
3011 login=NEGOTIATE:principal_name
3012 If this is a personal/workgroup proxy and your parent
3013 requires a secure proxy authentication.
3014 The principal principal_name from the default keytab or
3015 defined by the environment variable KRB5_KTNAME will be
3018 WARNING: The connection may transmit requests from multiple
3019 clients. Negotiate often assumes end-to-end authentication
3020 and a single-client. Which is not strictly true here.
3022 connection-auth=on|off
3023 Tell Squid that this peer does or not support Microsoft
3024 connection oriented authentication, and any such
3025 challenges received from there should be ignored.
3026 Default is auto to automatically determine the status
3030 ==== SSL / HTTPS / TLS OPTIONS ====
3032 ssl Encrypt connections to this peer with SSL/TLS.
3034 sslcert=/path/to/ssl/certificate
3035 A client SSL certificate to use when connecting to
3038 sslkey=/path/to/ssl/key
3039 The private SSL key corresponding to sslcert above.
3040 If 'sslkey' is not specified 'sslcert' is assumed to
3041 reference a combined file containing both the
3042 certificate and the key.
3044 sslversion=1|2|3|4|5|6
3045 The SSL version to use when connecting to this peer
3046 1 = automatic (default)
3053 sslcipher=... The list of valid SSL ciphers to use when connecting
3056 ssloptions=... Specify various SSL implementation options:
3058 NO_SSLv2 Disallow the use of SSLv2
3059 NO_SSLv3 Disallow the use of SSLv3
3060 NO_TLSv1 Disallow the use of TLSv1.0
3061 NO_TLSv1_1 Disallow the use of TLSv1.1
3062 NO_TLSv1_2 Disallow the use of TLSv1.2
3064 Always create a new key when using
3065 temporary/ephemeral DH key exchanges
3066 ALL Enable various bug workarounds
3067 suggested as "harmless" by OpenSSL
3068 Be warned that this reduces SSL/TLS
3069 strength to some attacks.
3071 See the OpenSSL SSL_CTX_set_options documentation for a
3074 sslcafile=... A file containing additional CA certificates to use
3075 when verifying the peer certificate.
3077 sslcapath=... A directory containing additional CA certificates to
3078 use when verifying the peer certificate.
3080 sslcrlfile=... A certificate revocation list file to use when
3081 verifying the peer certificate.
3083 sslflags=... Specify various flags modifying the SSL implementation:
3086 Accept certificates even if they fail to
3089 Don't use the default CA list built in
3092 Don't verify the peer certificate
3093 matches the server name
3095 ssldomain= The peer name as advertised in it's certificate.
3096 Used for verifying the correctness of the received peer
3097 certificate. If not specified the peer hostname will be
3101 Enable the "Front-End-Https: On" header needed when
3102 using Squid as a SSL frontend in front of Microsoft OWA.
3103 See MS KB document Q307347 for details on this header.
3104 If set to auto the header will only be added if the
3105 request is forwarded as a https:// URL.
3108 ==== GENERAL OPTIONS ====
3111 A peer-specific connect timeout.
3112 Also see the peer_connect_timeout directive.
3114 connect-fail-limit=N
3115 How many times connecting to a peer must fail before
3116 it is marked as down. Default is 10.
3118 allow-miss Disable Squid's use of only-if-cached when forwarding
3119 requests to siblings. This is primarily useful when
3120 icp_hit_stale is used by the sibling. To extensive use
3121 of this option may result in forwarding loops, and you
3122 should avoid having two-way peerings with this option.
3123 For example to deny peer usage on requests from peer
3124 by denying cache_peer_access if the source is a peer.
3126 max-conn=N Limit the amount of connections Squid may open to this
3129 name=xxx Unique name for the peer.
3130 Required if you have multiple peers on the same host
3131 but different ports.
3132 This name can be used in cache_peer_access and similar
3133 directives to dentify the peer.
3134 Can be used by outgoing access controls through the
3137 no-tproxy Do not use the client-spoof TPROXY support when forwarding
3138 requests to this peer. Use normal address selection instead.
3139 This overrides the spoof_client_ip ACL.
3141 proxy-only objects fetched from the peer will not be stored locally.
3145 NAME: cache_peer_domain cache_host_domain
3150 Use to limit the domains for which a neighbor cache will be
3154 cache_peer_domain cache-host domain [domain ...]
3155 cache_peer_domain cache-host !domain
3157 For example, specifying
3159 cache_peer_domain parent.foo.net .edu
3161 has the effect such that UDP query packets are sent to
3162 'bigserver' only when the requested object exists on a
3163 server in the .edu domain. Prefixing the domainname
3164 with '!' means the cache will be queried for objects
3167 NOTE: * Any number of domains may be given for a cache-host,
3168 either on the same or separate lines.
3169 * When multiple domains are given for a particular
3170 cache-host, the first matched domain is applied.
3171 * Cache hosts with no domain restrictions are queried
3173 * There are no defaults.
3174 * There is also a 'cache_peer_access' tag in the ACL
3178 NAME: cache_peer_access
3183 Similar to 'cache_peer_domain' but provides more flexibility by
3187 cache_peer_access cache-host allow|deny [!]aclname ...
3189 The syntax is identical to 'http_access' and the other lists of
3190 ACL elements. See the comments for 'http_access' below, or
3191 the Squid FAQ (http://wiki.squid-cache.org/SquidFaq/SquidAcl).
3194 NAME: neighbor_type_domain
3195 TYPE: hostdomaintype
3197 DEFAULT_DOC: The peer type from cache_peer directive is used for all requests to that peer.
3200 Modify the cache_peer neighbor type when passing requests
3201 about specific domains to the peer.
3204 neighbor_type_domain neighbor parent|sibling domain domain ...
3207 cache_peer foo.example.com parent 3128 3130
3208 neighbor_type_domain foo.example.com sibling .au .de
3210 The above configuration treats all requests to foo.example.com as a
3211 parent proxy unless the request is for a .au or .de ccTLD domain name.
3214 NAME: dead_peer_timeout
3218 LOC: Config.Timeout.deadPeer
3220 This controls how long Squid waits to declare a peer cache
3221 as "dead." If there are no ICP replies received in this
3222 amount of time, Squid will declare the peer dead and not
3223 expect to receive any further ICP replies. However, it
3224 continues to send ICP queries, and will mark the peer as
3225 alive upon receipt of the first subsequent ICP reply.
3227 This timeout also affects when Squid expects to receive ICP
3228 replies from peers. If more than 'dead_peer' seconds have
3229 passed since the last ICP reply was received, Squid will not
3230 expect to receive an ICP reply on the next query. Thus, if
3231 your time between requests is greater than this timeout, you
3232 will see a lot of requests sent DIRECT to origin servers
3233 instead of to your parents.
3236 NAME: forward_max_tries
3239 LOC: Config.forward_max_tries
3241 Controls how many different forward paths Squid will try
3242 before giving up. See also forward_timeout.
3244 NOTE: connect_retries (default: none) can make each of these
3245 possible forwarding paths be tried multiple times.
3248 NAME: hierarchy_stoplist
3251 LOC: Config.hierarchy_stoplist
3253 A list of words which, if found in a URL, cause the object to
3254 be handled directly by this cache. In other words, use this
3255 to not query neighbor caches for certain objects. You may
3256 list this option multiple times.
3259 hierarchy_stoplist cgi-bin ?
3261 Note: never_direct overrides this option.
3265 MEMORY CACHE OPTIONS
3266 -----------------------------------------------------------------------------
3273 LOC: Config.memMaxSize
3275 NOTE: THIS PARAMETER DOES NOT SPECIFY THE MAXIMUM PROCESS SIZE.
3276 IT ONLY PLACES A LIMIT ON HOW MUCH ADDITIONAL MEMORY SQUID WILL
3277 USE AS A MEMORY CACHE OF OBJECTS. SQUID USES MEMORY FOR OTHER
3278 THINGS AS WELL. SEE THE SQUID FAQ SECTION 8 FOR DETAILS.
3280 'cache_mem' specifies the ideal amount of memory to be used
3282 * In-Transit objects
3284 * Negative-Cached objects
3286 Data for these objects are stored in 4 KB blocks. This
3287 parameter specifies the ideal upper limit on the total size of
3288 4 KB blocks allocated. In-Transit objects take the highest
3291 In-transit objects have priority over the others. When
3292 additional space is needed for incoming data, negative-cached
3293 and hot objects will be released. In other words, the
3294 negative-cached and hot objects will fill up any unused space
3295 not needed for in-transit objects.
3297 If circumstances require, this limit will be exceeded.
3298 Specifically, if your incoming request rate requires more than
3299 'cache_mem' of memory to hold in-transit objects, Squid will
3300 exceed this limit to satisfy the new requests. When the load
3301 decreases, blocks will be freed until the high-water mark is
3302 reached. Thereafter, blocks will be used to store hot
3305 If shared memory caching is enabled, Squid does not use the shared
3306 cache space for in-transit objects, but they still consume as much
3307 local memory as they need. For more details about the shared memory
3308 cache, see memory_cache_shared.
3311 NAME: maximum_object_size_in_memory
3315 LOC: Config.Store.maxInMemObjSize
3317 Objects greater than this size will not be attempted to kept in
3318 the memory cache. This should be set high enough to keep objects
3319 accessed frequently in memory to improve performance whilst low
3320 enough to keep larger objects from hoarding cache_mem.
3323 NAME: memory_cache_shared
3326 LOC: Config.memShared
3328 DEFAULT_DOC: "on" where supported if doing memory caching with multiple SMP workers.
3330 Controls whether the memory cache is shared among SMP workers.
3332 The shared memory cache is meant to occupy cache_mem bytes and replace
3333 the non-shared memory cache, although some entities may still be
3334 cached locally by workers for now (e.g., internal and in-transit
3335 objects may be served from a local memory cache even if shared memory
3336 caching is enabled).
3338 By default, the memory cache is shared if and only if all of the
3339 following conditions are satisfied: Squid runs in SMP mode with
3340 multiple workers, cache_mem is positive, and Squid environment
3341 supports required IPC primitives (e.g., POSIX shared memory segments
3342 and GCC-style atomic operations).
3344 To avoid blocking locks, shared memory uses opportunistic algorithms
3345 that do not guarantee that every cachable entity that could have been
3346 shared among SMP workers will actually be shared.
3348 Currently, entities exceeding 32KB in size cannot be shared.
3351 NAME: memory_cache_mode
3355 DEFAULT_DOC: Keep the most recently fetched objects in memory
3357 Controls which objects to keep in the memory cache (cache_mem)
3359 always Keep most recently fetched objects in memory (default)
3361 disk Only disk cache hits are kept in memory, which means
3362 an object must first be cached on disk and then hit
3363 a second time before cached in memory.
3365 network Only objects fetched from network is kept in memory
3368 NAME: memory_replacement_policy
3370 LOC: Config.memPolicy
3373 The memory replacement policy parameter determines which
3374 objects are purged from memory when memory space is needed.
3376 See cache_replacement_policy for details on algorithms.
3381 -----------------------------------------------------------------------------
3384 NAME: cache_replacement_policy
3386 LOC: Config.replPolicy
3389 The cache replacement policy parameter determines which
3390 objects are evicted (replaced) when disk space is needed.
3392 lru : Squid's original list based LRU policy
3393 heap GDSF : Greedy-Dual Size Frequency
3394 heap LFUDA: Least Frequently Used with Dynamic Aging
3395 heap LRU : LRU policy implemented using a heap
3397 Applies to any cache_dir lines listed below this directive.
3399 The LRU policies keeps recently referenced objects.
3401 The heap GDSF policy optimizes object hit rate by keeping smaller
3402 popular objects in cache so it has a better chance of getting a
3403 hit. It achieves a lower byte hit rate than LFUDA though since
3404 it evicts larger (possibly popular) objects.
3406 The heap LFUDA policy keeps popular objects in cache regardless of
3407 their size and thus optimizes byte hit rate at the expense of
3408 hit rate since one large, popular object will prevent many
3409 smaller, slightly less popular objects from being cached.
3411 Both policies utilize a dynamic aging mechanism that prevents
3412 cache pollution that can otherwise occur with frequency-based
3413 replacement policies.
3415 NOTE: if using the LFUDA replacement policy you should increase
3416 the value of maximum_object_size above its default of 4 MB to
3417 to maximize the potential byte hit rate improvement of LFUDA.
3419 For more information about the GDSF and LFUDA cache replacement
3420 policies see http://www.hpl.hp.com/techreports/1999/HPL-1999-69.html
3421 and http://fog.hpl.external.hp.com/techreports/98/HPL-98-173.html.
3424 NAME: minimum_object_size
3428 DEFAULT_DOC: no limit
3429 LOC: Config.Store.minObjectSize
3431 Objects smaller than this size will NOT be saved on disk. The
3432 value is specified in bytes, and the default is 0 KB, which
3433 means all responses can be stored.
3436 NAME: maximum_object_size
3440 LOC: Config.Store.maxObjectSize
3442 Set the default value for max-size parameter on any cache_dir
3445 The value is specified in bytes, and the default is 4 MB.
3447 If you wish to get a high BYTES hit ratio, you should probably
3448 increase this (one 32 MB object hit counts for 3200 10KB
3451 If you wish to increase hit ratio more than you want to
3452 save bandwidth you should leave this low.
3454 NOTE: if using the LFUDA replacement policy you should increase
3455 this value to maximize the byte hit rate improvement of LFUDA!
3456 See cache_replacement_policy for a discussion of this policy.
3462 DEFAULT_DOC: No disk cache. Store cache ojects only in memory.
3463 LOC: Config.cacheSwap
3466 cache_dir Type Directory-Name Fs-specific-data [options]
3468 You can specify multiple cache_dir lines to spread the
3469 cache among different disk partitions.
3471 Type specifies the kind of storage system to use. Only "ufs"
3472 is built by default. To enable any of the other storage systems
3473 see the --enable-storeio configure option.
3475 'Directory' is a top-level directory where cache swap
3476 files will be stored. If you want to use an entire disk
3477 for caching, this can be the mount-point directory.
3478 The directory must exist and be writable by the Squid
3479 process. Squid will NOT create this directory for you.
3481 In SMP configurations, cache_dir must not precede the workers option
3482 and should use configuration macros or conditionals to give each
3483 worker interested in disk caching a dedicated cache directory.
3486 ==== The ufs store type ====
3488 "ufs" is the old well-known Squid storage format that has always
3492 cache_dir ufs Directory-Name Mbytes L1 L2 [options]
3494 'Mbytes' is the amount of disk space (MB) to use under this
3495 directory. The default is 100 MB. Change this to suit your
3496 configuration. Do NOT put the size of your disk drive here.
3497 Instead, if you want Squid to use the entire disk drive,
3498 subtract 20% and use that value.
3500 'L1' is the number of first-level subdirectories which
3501 will be created under the 'Directory'. The default is 16.
3503 'L2' is the number of second-level subdirectories which
3504 will be created under each first-level directory. The default
3508 ==== The aufs store type ====
3510 "aufs" uses the same storage format as "ufs", utilizing
3511 POSIX-threads to avoid blocking the main Squid process on
3512 disk-I/O. This was formerly known in Squid as async-io.
3515 cache_dir aufs Directory-Name Mbytes L1 L2 [options]
3517 see argument descriptions under ufs above
3520 ==== The diskd store type ====
3522 "diskd" uses the same storage format as "ufs", utilizing a
3523 separate process to avoid blocking the main Squid process on
3527 cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n]
3529 see argument descriptions under ufs above
3531 Q1 specifies the number of unacknowledged I/O requests when Squid
3532 stops opening new files. If this many messages are in the queues,
3533 Squid won't open new files. Default is 64
3535 Q2 specifies the number of unacknowledged messages when Squid
3536 starts blocking. If this many messages are in the queues,
3537 Squid blocks until it receives some replies. Default is 72
3539 When Q1 < Q2 (the default), the cache directory is optimized
3540 for lower response time at the expense of a decrease in hit
3541 ratio. If Q1 > Q2, the cache directory is optimized for
3542 higher hit ratio at the expense of an increase in response
3546 ==== The rock store type ====
3549 cache_dir rock Directory-Name Mbytes [options]
3551 The Rock Store type is a database-style storage. All cached
3552 entries are stored in a "database" file, using fixed-size slots.
3553 A single entry occupies one or more slots.
3555 If possible, Squid using Rock Store creates a dedicated kid
3556 process called "disker" to avoid blocking Squid worker(s) on disk
3557 I/O. One disker kid is created for each rock cache_dir. Diskers
3558 are created only when Squid, running in daemon mode, has support
3559 for the IpcIo disk I/O module.
3561 swap-timeout=msec: Squid will not start writing a miss to or
3562 reading a hit from disk if it estimates that the swap operation
3563 will take more than the specified number of milliseconds. By
3564 default and when set to zero, disables the disk I/O time limit
3565 enforcement. Ignored when using blocking I/O module because
3566 blocking synchronous I/O does not allow Squid to estimate the
3567 expected swap wait time.
3569 max-swap-rate=swaps/sec: Artificially limits disk access using
3570 the specified I/O rate limit. Swap out requests that
3571 would cause the average I/O rate to exceed the limit are
3572 delayed. Individual swap in requests (i.e., hits or reads) are
3573 not delayed, but they do contribute to measured swap rate and
3574 since they are placed in the same FIFO queue as swap out
3575 requests, they may wait longer if max-swap-rate is smaller.
3576 This is necessary on file systems that buffer "too
3577 many" writes and then start blocking Squid and other processes
3578 while committing those writes to disk. Usually used together
3579 with swap-timeout to avoid excessive delays and queue overflows
3580 when disk demand exceeds available disk "bandwidth". By default
3581 and when set to zero, disables the disk I/O rate limit
3582 enforcement. Currently supported by IpcIo module only.
3584 slot-size=bytes: The size of a database "record" used for
3585 storing cached responses. A cached response occupies at least
3586 one slot and all database I/O is done using individual slots so
3587 increasing this parameter leads to more disk space waste while
3588 decreasing it leads to more disk I/O overheads. Should be a
3589 multiple of your operating system I/O page size. Defaults to
3590 16KBytes. A housekeeping header is stored with each slot and
3591 smaller slot-sizes will be rejected. The header is smaller than
3595 ==== COMMON OPTIONS ====
3597 no-store no new objects should be stored to this cache_dir.
3599 min-size=n the minimum object size in bytes this cache_dir
3600 will accept. It's used to restrict a cache_dir
3601 to only store large objects (e.g. AUFS) while
3602 other stores are optimized for smaller objects
3606 max-size=n the maximum object size in bytes this cache_dir
3608 The value in maximum_object_size directive above
3609 this cache_dir line sets a default unless more
3610 specific details are available (ie a small store
3613 Note: To make optimal use of the max-size limits you should order
3614 the cache_dir lines with the smallest max-size value first.
3618 # Uncomment and adjust the following to add a disk cache directory.
3619 #cache_dir ufs @DEFAULT_SWAP_DIR@ 100 16 256
3623 NAME: store_dir_select_algorithm
3625 LOC: Config.store_dir_select_algorithm
3628 How Squid selects which cache_dir to use when the response
3629 object will fit into more than one.
3631 Regardless of which algorithm is used the cache_dir min-size
3632 and max-size parameters are obeyed. As such they can affect
3633 the selection algorithm by limiting the set of considered
3640 This algorithm is suited to caches with similar cache_dir
3641 sizes and disk speeds.
3643 The disk with the least I/O pending is selected.
3644 When there are multiple disks with the same I/O load ranking
3645 the cache_dir with most available capacity is selected.
3647 When a mix of cache_dir sizes are configured the faster disks
3648 have a naturally lower I/O loading and larger disks have more
3649 capacity. So space used to store objects and data throughput
3650 may be very unbalanced towards larger disks.
3655 This algorithm is suited to caches with unequal cache_dir
3658 Each cache_dir is selected in a rotation. The next suitable
3661 Available cache_dir capacity is only considered in relation
3662 to whether the object will fit and meets the min-size and
3663 max-size parameters.
3665 Disk I/O loading is only considered to prevent overload on slow
3666 disks. This algorithm does not spread objects by size, so any
3667 I/O loading per-disk may appear very unbalanced and volatile.
3671 NAME: max_open_disk_fds
3673 LOC: Config.max_open_disk_fds
3675 DEFAULT_DOC: no limit
3677 To avoid having disk as the I/O bottleneck Squid can optionally
3678 bypass the on-disk cache if more than this amount of disk file
3679 descriptors are open.
3681 A value of 0 indicates no limit.
3684 NAME: cache_swap_low
3685 COMMENT: (percent, 0-100)
3688 LOC: Config.Swap.lowWaterMark
3690 The low-water mark for cache object replacement.
3691 Replacement begins when the swap (disk) usage is above the
3692 low-water mark and attempts to maintain utilization near the
3693 low-water mark. As swap utilization gets close to high-water
3694 mark object eviction becomes more aggressive. If utilization is
3695 close to the low-water mark less replacement is done each time.
3697 Defaults are 90% and 95%. If you have a large cache, 5% could be
3698 hundreds of MB. If this is the case you may wish to set these
3699 numbers closer together.
3701 See also cache_swap_high
3704 NAME: cache_swap_high
3705 COMMENT: (percent, 0-100)
3708 LOC: Config.Swap.highWaterMark
3710 The high-water mark for cache object replacement.
3711 Replacement begins when the swap (disk) usage is above the
3712 low-water mark and attempts to maintain utilization near the
3713 low-water mark. As swap utilization gets close to high-water
3714 mark object eviction becomes more aggressive. If utilization is
3715 close to the low-water mark less replacement is done each time.
3717 Defaults are 90% and 95%. If you have a large cache, 5% could be
3718 hundreds of MB. If this is the case you may wish to set these
3719 numbers closer together.
3721 See also cache_swap_low
3726 -----------------------------------------------------------------------------
3733 DEFAULT_DOC: The format definitions squid, common, combined, referrer, useragent are built in.
3737 logformat <name> <format specification>
3739 Defines an access log format.
3741 The <format specification> is a string with embedded % format codes
3743 % format codes all follow the same basic structure where all but
3744 the formatcode is optional. Output strings are automatically escaped
3745 as required according to their context and the output format
3746 modifiers are usually not needed, but can be specified if an explicit
3747 output format is desired.
3749 % ["|[|'|#] [-] [[0]width] [{argument}] formatcode
3751 " output in quoted string format
3752 [ output in squid text log format as used by log_mime_hdrs
3753 # output in URL quoted format
3758 width minimum and/or maximum field width:
3759 [width_min][.width_max]
3760 When minimum starts with 0, the field is zero-padded.
3761 String values exceeding maximum width are truncated.
3763 {arg} argument such as header name etc
3767 % a literal % character
3768 sn Unique sequence number per log line entry
3769 err_code The ID of an error response served by Squid or
3770 a similar internal error identifier.
3771 err_detail Additional err_code-dependent error information.
3772 note The meta header specified by the argument. Also
3773 logs the adaptation meta headers set by the
3774 adaptation_meta configuration parameter.
3775 If no argument given all meta headers logged.
3777 Connection related format codes:
3779 >a Client source IP address
3781 >p Client source port
3782 >eui Client source EUI (MAC address, EUI-48 or EUI-64 identifier)
3783 >la Local IP address the client connected to
3784 >lp Local port number the client connected to
3785 >qos Client connection TOS/DSCP value set by Squid
3786 >nfmark Client connection netfilter mark set by Squid
3788 la Local listening IP address the client connection was connected to.
3789 lp Local listening port number the client connection was connected to.
3791 <a Server IP address of the last server or peer connection
3792 <A Server FQDN or peer name
3793 <p Server port number of the last server or peer connection
3794 <la Local IP address of the last server or peer connection
3795 <lp Local port number of the last server or peer connection
3796 <qos Server connection TOS/DSCP value set by Squid
3797 <nfmark Server connection netfilter mark set by Squid
3799 Time related format codes:
3801 ts Seconds since epoch
3802 tu subsecond time (milliseconds)
3803 tl Local time. Optional strftime format argument
3804 default %d/%b/%Y:%H:%M:%S %z
3805 tg GMT time. Optional strftime format argument
3806 default %d/%b/%Y:%H:%M:%S %z
3807 tr Response time (milliseconds)
3808 dt Total time spent making DNS lookups (milliseconds)
3809 tS Approximate master transaction start time in
3810 <full seconds since epoch>.<fractional seconds> format.
3811 Currently, Squid considers the master transaction
3812 started when a complete HTTP request header initiating
3813 the transaction is received from the client. This is
3814 the same value that Squid uses to calculate transaction
3815 response time when logging %tr to access.log. Currently,
3816 Squid uses millisecond resolution for %tS values,
3817 similar to the default access.log "current time" field
3820 Access Control related format codes:
3822 et Tag returned by external acl
3823 ea Log string returned by external acl
3824 un User name (any available)
3825 ul User name from authentication
3826 ue User name from external acl helper
3827 ui User name from ident
3828 us User name from SSL
3829 credentials Client credentials. The exact meaning depends on
3830 the authentication scheme: For Basic authentication,
3831 it is the password; for Digest, the realm sent by the
3832 client; for NTLM and Negotiate, the client challenge
3833 or client credentials prefixed with "YR " or "KK ".
3835 HTTP related format codes:
3839 [http::]rm Request method (GET/POST etc)
3840 [http::]>rm Request method from client
3841 [http::]<rm Request method sent to server or peer
3842 [http::]ru Request URL from client (historic, filtered for logging)
3843 [http::]>ru Request URL from client
3844 [http::]<ru Request URL sent to server or peer
3845 [http::]>rd Request URL domain from client
3846 [http::]rp Request URL-Path excluding hostname
3847 [http::]>rp Request URL-Path excluding hostname from client
3848 [http::]<rp Request URL-Path excluding hostname sent to server or peer
3849 [http::]rv Request protocol version
3850 [http::]>rv Request protocol version from client
3851 [http::]<rv Request protocol version sent to server or peer
3853 [http::]>h Original received request header.
3854 Usually differs from the request header sent by
3855 Squid, although most fields are often preserved.
3856 Accepts optional header field name/value filter
3857 argument using name[:[separator]element] format.
3858 [http::]>ha Received request header after adaptation and
3859 redirection (pre-cache REQMOD vectoring point).
3860 Usually differs from the request header sent by
3861 Squid, although most fields are often preserved.
3862 Optional header name argument as for >h
3867 [http::]<Hs HTTP status code received from the next hop
3868 [http::]>Hs HTTP status code sent to the client
3870 [http::]<h Reply header. Optional header name argument
3873 [http::]mt MIME content type
3878 [http::]st Total size of request + reply traffic with client
3879 [http::]>st Total size of request received from client.
3880 Excluding chunked encoding bytes.
3881 [http::]<st Total size of reply sent to client (after adaptation)
3883 [http::]>sh Size of request headers received from client
3884 [http::]<sh Size of reply headers sent to client (after adaptation)
3886 [http::]<sH Reply high offset sent
3887 [http::]<sS Upstream object size
3889 [http::]<bs Number of HTTP-equivalent message body bytes
3890 received from the next hop, excluding chunked
3891 transfer encoding and control messages.
3892 Generated FTP/Gopher listings are treated as
3898 [http::]<pt Peer response time in milliseconds. The timer starts
3899 when the last request byte is sent to the next hop
3900 and stops when the last response byte is received.
3901 [http::]<tt Total server-side time in milliseconds. The timer
3902 starts with the first connect request (or write I/O)
3903 sent to the first selected peer. The timer stops
3904 with the last I/O with the last peer.
3906 Squid handling related format codes:
3908 Ss Squid request status (TCP_MISS etc)
3909 Sh Squid hierarchy status (DEFAULT_PARENT etc)
3911 SSL-related format codes:
3913 ssl::bump_mode SslBump decision for the transaction:
3915 For CONNECT requests that initiated bumping of
3916 a connection and for any request received on
3917 an already bumped connection, Squid logs the
3918 corresponding SslBump mode ("server-first" or
3919 "client-first"). See the ssl_bump option for
3920 more information about these modes.
3922 A "none" token is logged for requests that
3923 triggered "ssl_bump" ACL evaluation matching
3924 either a "none" rule or no rules at all.
3926 In all other cases, a single dash ("-") is
3929 If ICAP is enabled, the following code becomes available (as
3930 well as ICAP log codes documented with the icap_log option):
3932 icap::tt Total ICAP processing time for the HTTP
3933 transaction. The timer ticks when ICAP
3934 ACLs are checked and when ICAP
3935 transaction is in progress.
3937 If adaptation is enabled the following three codes become available:
3939 adapt::<last_h The header of the last ICAP response or
3940 meta-information from the last eCAP
3941 transaction related to the HTTP transaction.
3942 Like <h, accepts an optional header name
3945 adapt::sum_trs Summed adaptation transaction response
3946 times recorded as a comma-separated list in
3947 the order of transaction start time. Each time
3948 value is recorded as an integer number,
3949 representing response time of one or more
3950 adaptation (ICAP or eCAP) transaction in
3951 milliseconds. When a failed transaction is
3952 being retried or repeated, its time is not
3953 logged individually but added to the
3954 replacement (next) transaction. See also:
3957 adapt::all_trs All adaptation transaction response times.
3958 Same as adaptation_strs but response times of
3959 individual transactions are never added
3960 together. Instead, all transaction response
3961 times are recorded individually.
3963 You can prefix adapt::*_trs format codes with adaptation
3964 service name in curly braces to record response time(s) specific
3965 to that service. For example: %{my_service}adapt::sum_trs
3967 If SSL is enabled, the following formating codes become available:
3969 %ssl::>cert_subject The Subject field of the received client
3970 SSL certificate or a dash ('-') if Squid has
3971 received an invalid/malformed certificate or
3972 no certificate at all. Consider encoding the
3973 logged value because Subject often has spaces.
3975 %ssl::>cert_issuer The Issuer field of the received client
3976 SSL certificate or a dash ('-') if Squid has
3977 received an invalid/malformed certificate or
3978 no certificate at all. Consider encoding the
3979 logged value because Issuer often has spaces.
3981 The default formats available (which do not need re-defining) are:
3983 logformat squid %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %[un %Sh/%<a %mt
3984 logformat common %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st %Ss:%Sh
3985 logformat combined %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
3986 logformat referrer %ts.%03tu %>a %{Referer}>h %ru
3987 logformat useragent %>a [%tl] "%{User-Agent}>h"
3989 NOTE: When the log_mime_hdrs directive is set to ON.
3990 The squid, common and combined formats have a safely encoded copy
3991 of the mime headers appended to each line within a pair of brackets.
3993 NOTE: The common and combined formats are not quite true to the Apache definition.
3994 The logs from Squid contain an extra status and hierarchy code appended.
3998 NAME: access_log cache_access_log
4000 LOC: Config.Log.accesslogs
4001 DEFAULT_IF_NONE: daemon:@DEFAULT_ACCESS_LOG@ squid
4003 Configures whether and how Squid logs HTTP and ICP transactions.
4004 If access logging is enabled, a single line is logged for every
4005 matching HTTP or ICP request. The recommended directive formats are:
4007 access_log <module>:<place> [option ...] [acl acl ...]
4008 access_log none [acl acl ...]
4010 The following directive format is accepted but may be deprecated:
4011 access_log <module>:<place> [<logformat name> [acl acl ...]]
4013 In most cases, the first ACL name must not contain the '=' character
4014 and should not be equal to an existing logformat name. You can always
4015 start with an 'all' ACL to work around those restrictions.
4017 Will log to the specified module:place using the specified format (which
4018 must be defined in a logformat directive) those entries which match
4019 ALL the acl's specified (which must be defined in acl clauses).
4020 If no acl is specified, all requests will be logged to this destination.
4022 ===== Available options for the recommended directive format =====
4024 logformat=name Names log line format (either built-in or
4025 defined by a logformat directive). Defaults
4028 buffer-size=64KB Defines approximate buffering limit for log
4029 records (see buffered_logs). Squid should not
4030 keep more than the specified size and, hence,
4031 should flush records before the buffer becomes
4032 full to avoid overflows under normal
4033 conditions (the exact flushing algorithm is
4034 module-dependent though). The on-error option
4035 controls overflow handling.
4037 on-error=die|drop Defines action on unrecoverable errors. The
4038 'drop' action ignores (i.e., does not log)
4039 affected log records. The default 'die' action
4040 kills the affected worker. The drop action
4041 support has not been tested for modules other
4044 ===== Modules Currently available =====
4046 none Do not log any requests matching these ACL.
4047 Do not specify Place or logformat name.
4049 stdio Write each log line to disk immediately at the completion of
4051 Place: the filename and path to be written.
4053 daemon Very similar to stdio. But instead of writing to disk the log
4054 line is passed to a daemon helper for asychronous handling instead.
4055 Place: varies depending on the daemon.
4057 log_file_daemon Place: the file name and path to be written.
4059 syslog To log each request via syslog facility.
4060 Place: The syslog facility and priority level for these entries.
4061 Place Format: facility.priority
4063 where facility could be any of:
4064 authpriv, daemon, local0 ... local7 or user.
4066 And priority could be any of:
4067 err, warning, notice, info, debug.
4069 udp To send each log line as text data to a UDP receiver.
4070 Place: The destination host name or IP and port.
4071 Place Format: //host:port
4073 tcp To send each log line as text data to a TCP receiver.
4074 Lines may be accumulated before sending (see buffered_logs).
4075 Place: The destination host name or IP and port.
4076 Place Format: //host:port
4079 access_log daemon:@DEFAULT_ACCESS_LOG@ squid
4085 LOC: Config.Log.icaplogs
4088 ICAP log files record ICAP transaction summaries, one line per
4091 The icap_log option format is:
4092 icap_log <filepath> [<logformat name> [acl acl ...]]
4093 icap_log none [acl acl ...]]
4095 Please see access_log option documentation for details. The two
4096 kinds of logs share the overall configuration approach and many
4099 ICAP processing of a single HTTP message or transaction may
4100 require multiple ICAP transactions. In such cases, multiple
4101 ICAP transaction log lines will correspond to a single access
4104 ICAP log uses logformat codes that make sense for an ICAP
4105 transaction. Header-related codes are applied to the HTTP header
4106 embedded in an ICAP server response, with the following caveats:
4107 For REQMOD, there is no HTTP response header unless the ICAP
4108 server performed request satisfaction. For RESPMOD, the HTTP
4109 request header is the header sent to the ICAP server. For
4110 OPTIONS, there are no HTTP headers.
4112 The following format codes are also available for ICAP logs:
4114 icap::<A ICAP server IP address. Similar to <A.
4116 icap::<service_name ICAP service name from the icap_service
4117 option in Squid configuration file.
4119 icap::ru ICAP Request-URI. Similar to ru.
4121 icap::rm ICAP request method (REQMOD, RESPMOD, or
4122 OPTIONS). Similar to existing rm.
4124 icap::>st Bytes sent to the ICAP server (TCP payload
4125 only; i.e., what Squid writes to the socket).
4127 icap::<st Bytes received from the ICAP server (TCP
4128 payload only; i.e., what Squid reads from
4131 icap::<bs Number of message body bytes received from the
4132 ICAP server. ICAP message body, if any, usually
4133 includes encapsulated HTTP message headers and
4134 possibly encapsulated HTTP message body. The
4135 HTTP body part is dechunked before its size is
4138 icap::tr Transaction response time (in
4139 milliseconds). The timer starts when
4140 the ICAP transaction is created and
4141 stops when the transaction is completed.
4144 icap::tio Transaction I/O time (in milliseconds). The
4145 timer starts when the first ICAP request
4146 byte is scheduled for sending. The timers
4147 stops when the last byte of the ICAP response
4150 icap::to Transaction outcome: ICAP_ERR* for all
4151 transaction errors, ICAP_OPT for OPTION
4152 transactions, ICAP_ECHO for 204
4153 responses, ICAP_MOD for message
4154 modification, and ICAP_SAT for request
4155 satisfaction. Similar to Ss.
4157 icap::Hs ICAP response status code. Similar to Hs.
4159 icap::>h ICAP request header(s). Similar to >h.
4161 icap::<h ICAP response header(s). Similar to <h.
4163 The default ICAP log format, which can be used without an explicit
4164 definition, is called icap_squid:
4166 logformat icap_squid %ts.%03tu %6icap::tr %>a %icap::to/%03icap::Hs %icap::<size %icap::rm %icap::ru% %un -/%icap::<A -
4168 See also: logformat, log_icap, and %adapt::<last_h
4171 NAME: logfile_daemon
4173 DEFAULT: @DEFAULT_LOGFILED@
4174 LOC: Log::TheConfig.logfile_daemon
4176 Specify the path to the logfile-writing daemon. This daemon is
4177 used to write the access and store logs, if configured.
4179 Squid sends a number of commands to the log daemon:
4180 L<data>\n - logfile data
4185 r<n>\n - set rotate count to <n>
4186 b<n>\n - 1 = buffer output, 0 = don't buffer output
4188 No responses is expected.
4194 Remove this line. Use acls with access_log directives to control access logging
4200 Remove this line. Use acls with icap_log directives to control icap logging
4203 NAME: stats_collection
4205 LOC: Config.accessList.stats_collection
4207 DEFAULT_DOC: Allow logging for all transactions.
4208 COMMENT: allow|deny acl acl...
4210 This options allows you to control which requests gets accounted
4211 in performance counters.
4213 This clause only supports fast acl types.
4214 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4217 NAME: cache_store_log
4220 LOC: Config.Log.store
4222 Logs the activities of the storage manager. Shows which
4223 objects are ejected from the cache, and which objects are
4224 saved and for how long.
4225 There are not really utilities to analyze this data, so you can safely
4226 disable it (the default).
4228 Store log uses modular logging outputs. See access_log for the list
4229 of modules supported.
4232 cache_store_log stdio:@DEFAULT_STORE_LOG@
4233 cache_store_log daemon:@DEFAULT_STORE_LOG@
4236 NAME: cache_swap_state cache_swap_log
4238 LOC: Config.Log.swap
4240 DEFAULT_DOC: Store the journal inside its cache_dir
4242 Location for the cache "swap.state" file. This index file holds
4243 the metadata of objects saved on disk. It is used to rebuild
4244 the cache during startup. Normally this file resides in each
4245 'cache_dir' directory, but you may specify an alternate
4246 pathname here. Note you must give a full filename, not just
4247 a directory. Since this is the index for the whole object
4248 list you CANNOT periodically rotate it!
4250 If %s can be used in the file name it will be replaced with a
4251 a representation of the cache_dir name where each / is replaced
4252 with '.'. This is needed to allow adding/removing cache_dir
4253 lines when cache_swap_log is being used.
4255 If have more than one 'cache_dir', and %s is not used in the name
4256 these swap logs will have names such as:
4262 The numbered extension (which is added automatically)
4263 corresponds to the order of the 'cache_dir' lines in this
4264 configuration file. If you change the order of the 'cache_dir'
4265 lines in this file, these index files will NOT correspond to
4266 the correct 'cache_dir' entry (unless you manually rename
4267 them). We recommend you do NOT use this option. It is
4268 better to keep these index files in each 'cache_dir' directory.
4271 NAME: logfile_rotate
4274 LOC: Config.Log.rotateNumber
4276 Specifies the number of logfile rotations to make when you
4277 type 'squid -k rotate'. The default is 10, which will rotate
4278 with extensions 0 through 9. Setting logfile_rotate to 0 will
4279 disable the file name rotation, but the logfiles are still closed
4280 and re-opened. This will enable you to rename the logfiles
4281 yourself just before sending the rotate signal.
4283 Note, the 'squid -k rotate' command normally sends a USR1
4284 signal to the running squid process. In certain situations
4285 (e.g. on Linux with Async I/O), USR1 is used for other
4286 purposes, so -k rotate uses another signal. It is best to get
4287 in the habit of using 'squid -k rotate' instead of 'kill -USR1
4290 Note, from Squid-3.1 this option is only a default for cache.log,
4291 that log can be rotated separately by using debug_options.
4294 NAME: emulate_httpd_log
4297 Replace this with an access_log directive using the format 'common' or 'combined'.
4300 NAME: log_ip_on_direct
4303 Remove this option from your config. To log server or peer names use %<A in the log format.
4308 DEFAULT: @DEFAULT_MIME_TABLE@
4309 LOC: Config.mimeTablePathname
4311 Path to Squid's icon configuration file.
4313 You shouldn't need to change this, but the default file contains
4314 examples and formatting information if you do.
4320 LOC: Config.onoff.log_mime_hdrs
4323 The Cache can record both the request and the response MIME
4324 headers for each HTTP transaction. The headers are encoded
4325 safely and will appear as two bracketed fields at the end of
4326 the access log (for either the native or httpd-emulated log
4327 formats). To enable this logging set log_mime_hdrs to 'on'.
4333 Replace this with an access_log directive using the format 'useragent'.
4336 NAME: referer_log referrer_log
4339 Replace this with an access_log directive using the format 'referrer'.
4344 DEFAULT: @DEFAULT_PID_FILE@
4345 LOC: Config.pidFilename
4347 A filename to write the process-id to. To disable, enter "none".
4353 Remove this option from your config. To log FQDN use %>A in the log format.
4356 NAME: client_netmask
4358 LOC: Config.Addrs.client_netmask
4360 DEFAULT_DOC: Log full client IP address
4362 A netmask for client addresses in logfiles and cachemgr output.
4363 Change this to protect the privacy of your cache clients.
4364 A netmask of 255.255.255.0 will log all IP's in that range with
4365 the last digit set to '0'.
4371 Use a regular access.log with ACL limiting it to MISS events.
4374 NAME: strip_query_terms
4376 LOC: Config.onoff.strip_query_terms
4379 By default, Squid strips query terms from requested URLs before
4380 logging. This protects your user's privacy and reduces log size.
4382 When investigating HIT/MISS or other caching behaviour you
4383 will need to disable this to see the full URL used by Squid.
4390 LOC: Config.onoff.buffered_logs
4392 Whether to write/send access_log records ASAP or accumulate them and
4393 then write/send them in larger chunks. Buffering may improve
4394 performance because it decreases the number of I/Os. However,
4395 buffering increases the delay before log records become available to
4396 the final recipient (e.g., a disk file or logging daemon) and,
4397 hence, increases the risk of log records loss.
4399 Note that even when buffered_logs are off, Squid may have to buffer
4400 records if it cannot write/send them immediately due to pending I/Os
4401 (e.g., the I/O writing the previous log record) or connectivity loss.
4403 Currently honored by 'daemon' and 'tcp' access_log modules only.
4406 NAME: netdb_filename
4408 DEFAULT: stdio:@DEFAULT_NETDB_FILE@
4409 LOC: Config.netdbFilename
4412 Where Squid stores it's netdb journal.
4413 When enabled this journal preserves netdb state between restarts.
4415 To disable, enter "none".
4419 OPTIONS FOR TROUBLESHOOTING
4420 -----------------------------------------------------------------------------
4425 DEFAULT_IF_NONE: @DEFAULT_CACHE_LOG@
4426 LOC: Debug::cache_log
4428 Squid administrative logging file.
4430 This is where general information about Squid behavior goes. You can
4431 increase the amount of data logged to this file and how often it is
4432 rotated with "debug_options"
4438 DEFAULT_DOC: Log all critical and important messages.
4439 LOC: Debug::debugOptions
4441 Logging options are set as section,level where each source file
4442 is assigned a unique section. Lower levels result in less
4443 output, Full debugging (level 9) can result in a very large
4444 log file, so be careful.
4446 The magic word "ALL" sets debugging levels for all sections.
4447 The default is to run with "ALL,1" to record important warnings.
4449 The rotate=N option can be used to keep more or less of these logs
4450 than would otherwise be kept by logfile_rotate.
4451 For most uses a single log should be enough to monitor current
4452 events affecting Squid.
4457 LOC: Config.coredump_dir
4458 DEFAULT_IF_NONE: none
4459 DEFAULT_DOC: Use the directory from where Squid was started.
4461 By default Squid leaves core files in the directory from where
4462 it was started. If you set 'coredump_dir' to a directory
4463 that exists, Squid will chdir() to that directory at startup
4464 and coredump files will be left there.
4468 # Leave coredumps in the first cache dir
4469 coredump_dir @DEFAULT_SWAP_DIR@
4475 OPTIONS FOR FTP GATEWAYING
4476 -----------------------------------------------------------------------------
4482 LOC: Config.Ftp.anon_user
4484 If you want the anonymous login password to be more informative
4485 (and enable the use of picky FTP servers), set this to something
4486 reasonable for your domain, like wwwuser@somewhere.net
4488 The reason why this is domainless by default is the
4489 request can be made on the behalf of a user in any domain,
4490 depending on how the cache is used.
4491 Some FTP server also validate the email address is valid
4492 (for example perl.com).
4498 LOC: Config.Ftp.passive
4500 If your firewall does not allow Squid to use passive
4501 connections, turn off this option.
4503 Use of ftp_epsv_all option requires this to be ON.
4509 LOC: Config.Ftp.epsv_all
4511 FTP Protocol extensions permit the use of a special "EPSV ALL" command.
4513 NATs may be able to put the connection on a "fast path" through the
4514 translator, as the EPRT command will never be used and therefore,
4515 translation of the data portion of the segments will never be needed.
4517 When a client only expects to do two-way FTP transfers this may be
4519 If squid finds that it must do a three-way FTP transfer after issuing
4520 an EPSV ALL command, the FTP session will fail.
4522 If you have any doubts about this option do not use it.
4523 Squid will nicely attempt all other connection methods.
4525 Requires ftp_passive to be ON (default) for any effect.
4531 LOC: Config.accessList.ftp_epsv
4533 FTP Protocol extensions permit the use of a special "EPSV" command.
4535 NATs may be able to put the connection on a "fast path" through the
4536 translator using EPSV, as the EPRT command will never be used
4537 and therefore, translation of the data portion of the segments
4538 will never be needed.
4540 EPSV is often required to interoperate with FTP servers on IPv6
4541 networks. On the other hand, it may break some IPv4 servers.
4543 By default, EPSV may try EPSV with any FTP server. To fine tune
4544 that decision, you may restrict EPSV to certain clients or servers
4547 ftp_epsv allow|deny al1 acl2 ...
4549 WARNING: Disabling EPSV may cause problems with external NAT and IPv6.
4551 Only fast ACLs are supported.
4552 Requires ftp_passive to be ON (default) for any effect.
4558 LOC: Config.Ftp.eprt
4560 FTP Protocol extensions permit the use of a special "EPRT" command.
4562 This extension provides a protocol neutral alternative to the
4563 IPv4-only PORT command. When supported it enables active FTP data
4564 channels over IPv6 and efficient NAT handling.
4566 Turning this OFF will prevent EPRT being attempted and will skip
4567 straight to using PORT for IPv4 servers.
4569 Some devices are known to not handle this extension correctly and
4570 may result in crashes. Devices which suport EPRT enough to fail
4571 cleanly will result in Squid attempting PORT anyway. This directive
4572 should only be disabled when EPRT results in device failures.
4574 WARNING: Doing so will convert Squid back to the old behavior with all
4575 the related problems with external NAT devices/layers and IPv4-only FTP.
4578 NAME: ftp_sanitycheck
4581 LOC: Config.Ftp.sanitycheck
4583 For security and data integrity reasons Squid by default performs
4584 sanity checks of the addresses of FTP data connections ensure the
4585 data connection is to the requested server. If you need to allow
4586 FTP connections to servers using another IP address for the data
4587 connection turn this off.
4590 NAME: ftp_telnet_protocol
4593 LOC: Config.Ftp.telnet
4595 The FTP protocol is officially defined to use the telnet protocol
4596 as transport channel for the control connection. However, many
4597 implementations are broken and does not respect this aspect of
4600 If you have trouble accessing files with ASCII code 255 in the
4601 path or similar problems involving this ASCII code you can
4602 try setting this directive to off. If that helps, report to the
4603 operator of the FTP server in question that their FTP server
4604 is broken and does not follow the FTP standard.
4608 OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
4609 -----------------------------------------------------------------------------
4614 DEFAULT: @DEFAULT_DISKD@
4615 LOC: Config.Program.diskd
4617 Specify the location of the diskd executable.
4618 Note this is only useful if you have compiled in
4619 diskd as one of the store io modules.
4622 NAME: unlinkd_program
4625 DEFAULT: @DEFAULT_UNLINKD@
4626 LOC: Config.Program.unlinkd
4628 Specify the location of the executable for file deletion process.
4631 NAME: pinger_program
4633 DEFAULT: @DEFAULT_PINGER@
4634 LOC: Config.pinger.program
4637 Specify the location of the executable for the pinger process.
4643 LOC: Config.pinger.enable
4646 Control whether the pinger is active at run-time.
4647 Enables turning ICMP pinger on and off with a simple
4648 squid -k reconfigure.
4653 OPTIONS FOR URL REWRITING
4654 -----------------------------------------------------------------------------
4657 NAME: url_rewrite_program redirect_program
4659 LOC: Config.Program.redirect
4662 Specify the location of the executable URL rewriter to use.
4663 Since they can perform almost any function there isn't one included.
4665 For each requested URL, the rewriter will receive on line with the format
4667 [channel-ID <SP>] URL [<SP> extras]<NL>
4670 After processing the request the helper must reply using the following format:
4672 [channel-ID <SP>] result [<SP> kv-pairs]
4674 The result code can be:
4676 OK status=30N url="..."
4677 Redirect the URL to the one supplied in 'url='.
4678 'status=' is optional and contains the status code to send
4679 the client in Squids HTTP response. It must be one of the
4680 HTTP redirect status codes: 301, 302, 303, 307, 308.
4681 When no status is given Squid will use 302.
4683 OK rewrite-url="..."
4684 Rewrite the URL to the one supplied in 'rewrite-url='.
4685 The new URL is fetched directly by Squid and returned to
4686 the client as the response to its request.
4689 When neither of url= and rewrite-url= are sent Squid does
4693 Do not change the URL.
4696 An internal error occurred in the helper, preventing
4697 a result being identified. The 'message=' key name is
4698 reserved for delivering a log message.
4701 In the future, the interface protocol will be extended with
4702 key=value pairs ("kv-pairs" shown above). Helper programs
4703 should be prepared to receive and possibly ignore additional
4704 whitespace-separated tokens on each input line.
4706 When using the concurrency= option the protocol is changed by
4707 introducing a query channel tag in front of the request/response.
4708 The query channel tag is a number between 0 and concurrency-1.
4709 This value must be echoed back unchanged to Squid as the first part
4710 of the response relating to its request.
4712 WARNING: URL re-writing ability should be avoided whenever possible.
4713 Use the URL redirect form of response instead.
4715 Re-write creates a difference in the state held by the client
4716 and server. Possibly causing confusion when the server response
4717 contains snippets of its view state. Embeded URLs, response
4718 and content Location headers, etc. are not re-written by this
4721 By default, a URL rewriter is not used.
4724 NAME: url_rewrite_children redirect_children
4725 TYPE: HelperChildConfig
4726 DEFAULT: 20 startup=0 idle=1 concurrency=0
4727 LOC: Config.redirectChildren
4729 The maximum number of redirector processes to spawn. If you limit
4730 it too few Squid will have to wait for them to process a backlog of
4731 URLs, slowing it down. If you allow too many they will use RAM
4732 and other system resources noticably.
4734 The startup= and idle= options allow some measure of skew in your
4739 Sets a minimum of how many processes are to be spawned when Squid
4740 starts or reconfigures. When set to zero the first request will
4741 cause spawning of the first child process to handle it.
4743 Starting too few will cause an initial slowdown in traffic as Squid
4744 attempts to simultaneously spawn enough processes to cope.
4748 Sets a minimum of how many processes Squid is to try and keep available
4749 at all times. When traffic begins to rise above what the existing
4750 processes can handle this many more will be spawned up to the maximum
4751 configured. A minimum setting of 1 is required.
4755 The number of requests each redirector helper can handle in
4756 parallel. Defaults to 0 which indicates the redirector
4757 is a old-style single threaded redirector.
4759 When this directive is set to a value >= 1 then the protocol
4760 used to communicate with the helper is modified to include
4761 an ID in front of the request/response. The ID from the request
4762 must be echoed back with the response to that request.
4765 NAME: url_rewrite_host_header redirect_rewrites_host_header
4768 LOC: Config.onoff.redir_rewrites_host
4770 To preserve same-origin security policies in browsers and
4771 prevent Host: header forgery by redirectors Squid rewrites
4772 any Host: header in redirected requests.
4774 If you are running an accelerator this may not be a wanted
4775 effect of a redirector. This directive enables you disable
4776 Host: alteration in reverse-proxy traffic.
4778 WARNING: Entries are cached on the result of the URL rewriting
4779 process, so be careful if you have domain-virtual hosts.
4781 WARNING: Squid and other software verifies the URL and Host
4782 are matching, so be careful not to relay through other proxies
4783 or inspecting firewalls with this disabled.
4786 NAME: url_rewrite_access redirector_access
4789 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
4790 LOC: Config.accessList.redirector
4792 If defined, this access list specifies which requests are
4793 sent to the redirector processes.
4795 This clause supports both fast and slow acl types.
4796 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4799 NAME: url_rewrite_bypass redirector_bypass
4801 LOC: Config.onoff.redirector_bypass
4804 When this is 'on', a request will not go through the
4805 redirector if all the helpers are busy. If this is 'off'
4806 and the redirector queue grows too large, Squid will exit
4807 with a FATAL error and ask you to increase the number of
4808 redirectors. You should only enable this if the redirectors
4809 are not critical to your caching system. If you use
4810 redirectors for access control, and you enable this option,
4811 users may have access to pages they should not
4812 be allowed to request.
4815 NAME: url_rewrite_extras
4816 TYPE: TokenOrQuotedString
4817 LOC: Config.redirector_extras
4818 DEFAULT: "%>a/%>A %un %>rm myip=%la myport=%lp"
4820 Specifies a string to be append to request line format for the
4821 rewriter helper. "Quoted" format values may contain spaces and
4822 logformat %macros. In theory, any logformat %macro can be used.
4823 In practice, a %macro expands as a dash (-) if the helper request is
4824 sent before the required macro information is available to Squid.
4828 OPTIONS FOR STORE ID
4829 -----------------------------------------------------------------------------
4832 NAME: store_id_program storeurl_rewrite_program
4834 LOC: Config.Program.store_id
4837 Specify the location of the executable StoreID helper to use.
4838 Since they can perform almost any function there isn't one included.
4840 For each requested URL, the helper will receive one line with the format
4842 [channel-ID <SP>] URL [<SP> extras]<NL>
4845 After processing the request the helper must reply using the following format:
4847 [channel-ID <SP>] result [<SP> kv-pairs]
4849 The result code can be:
4852 Use the StoreID supplied in 'store-id='.
4855 The default is to use HTTP request URL as the store ID.
4858 An internal error occured in the helper, preventing
4859 a result being identified.
4862 Helper programs should be prepared to receive and possibly ignore
4863 additional whitespace-separated tokens on each input line.
4865 When using the concurrency= option the protocol is changed by
4866 introducing a query channel tag in front of the request/response.
4867 The query channel tag is a number between 0 and concurrency-1.
4868 This value must be echoed back unchanged to Squid as the first part
4869 of the response relating to its request.
4871 NOTE: when using StoreID refresh_pattern will apply to the StoreID
4872 returned from the helper and not the URL.
4874 WARNING: Wrong StoreID value returned by a careless helper may result
4875 in the wrong cached response returned to the user.
4877 By default, a StoreID helper is not used.
4880 NAME: store_id_extras
4881 TYPE: TokenOrQuotedString
4882 LOC: Config.storeId_extras
4883 DEFAULT: "%>a/%>A %un %>rm myip=%la myport=%lp"
4885 Specifies a string to be append to request line format for the
4886 StoreId helper. "Quoted" format values may contain spaces and
4887 logformat %macros. In theory, any logformat %macro can be used.
4888 In practice, a %macro expands as a dash (-) if the helper request is
4889 sent before the required macro information is available to Squid.
4892 NAME: store_id_children storeurl_rewrite_children
4893 TYPE: HelperChildConfig
4894 DEFAULT: 20 startup=0 idle=1 concurrency=0
4895 LOC: Config.storeIdChildren
4897 The maximum number of StoreID helper processes to spawn. If you limit
4898 it too few Squid will have to wait for them to process a backlog of
4899 requests, slowing it down. If you allow too many they will use RAM
4900 and other system resources noticably.
4902 The startup= and idle= options allow some measure of skew in your
4907 Sets a minimum of how many processes are to be spawned when Squid
4908 starts or reconfigures. When set to zero the first request will
4909 cause spawning of the first child process to handle it.
4911 Starting too few will cause an initial slowdown in traffic as Squid
4912 attempts to simultaneously spawn enough processes to cope.
4916 Sets a minimum of how many processes Squid is to try and keep available
4917 at all times. When traffic begins to rise above what the existing
4918 processes can handle this many more will be spawned up to the maximum
4919 configured. A minimum setting of 1 is required.
4923 The number of requests each storeID helper can handle in
4924 parallel. Defaults to 0 which indicates the helper
4925 is a old-style single threaded program.
4927 When this directive is set to a value >= 1 then the protocol
4928 used to communicate with the helper is modified to include
4929 an ID in front of the request/response. The ID from the request
4930 must be echoed back with the response to that request.
4933 NAME: store_id_access storeurl_rewrite_access
4936 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
4937 LOC: Config.accessList.store_id
4939 If defined, this access list specifies which requests are
4940 sent to the StoreID processes. By default all requests
4943 This clause supports both fast and slow acl types.
4944 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4947 NAME: store_id_bypass storeurl_rewrite_bypass
4949 LOC: Config.onoff.store_id_bypass
4952 When this is 'on', a request will not go through the
4953 helper if all helpers are busy. If this is 'off'
4954 and the helper queue grows too large, Squid will exit
4955 with a FATAL error and ask you to increase the number of
4956 helpers. You should only enable this if the helperss
4957 are not critical to your caching system. If you use
4958 helpers for critical caching components, and you enable this
4959 option, users may not get objects from cache.
4963 OPTIONS FOR TUNING THE CACHE
4964 -----------------------------------------------------------------------------
4967 NAME: cache no_cache
4970 DEFAULT_DOC: By default, this directive is unused and has no effect.
4971 LOC: Config.accessList.noCache
4973 Requests denied by this directive will not be served from the cache
4974 and their responses will not be stored in the cache. This directive
4975 has no effect on other transactions and on already cached responses.
4977 This clause supports both fast and slow acl types.
4978 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4980 This and the two other similar caching directives listed below are
4981 checked at different transaction processing stages, have different
4982 access to response information, affect different cache operations,
4983 and differ in slow ACLs support:
4985 * cache: Checked before Squid makes a hit/miss determination.
4986 No access to reply information!
4987 Denies both serving a hit and storing a miss.
4988 Supports both fast and slow ACLs.
4989 * send_hit: Checked after a hit was detected.
4990 Has access to reply (hit) information.
4991 Denies serving a hit only.
4992 Supports fast ACLs only.
4993 * store_miss: Checked before storing a cachable miss.
4994 Has access to reply (miss) information.
4995 Denies storing a miss only.
4996 Supports fast ACLs only.
4998 If you are not sure which of the three directives to use, apply the
4999 following decision logic:
5001 * If your ACL(s) are of slow type _and_ need response info, redesign.
5002 Squid does not support that particular combination at this time.
5004 * If your directive ACL(s) are of slow type, use "cache"; and/or
5005 * if your directive ACL(s) need no response info, use "cache".
5007 * If you do not want the response cached, use store_miss; and/or
5008 * if you do not want a hit on a cached response, use send_hit.
5014 DEFAULT_DOC: By default, this directive is unused and has no effect.
5015 LOC: Config.accessList.sendHit
5017 Responses denied by this directive will not be served from the cache
5018 (but may still be cached, see store_miss). This directive has no
5019 effect on the responses it allows and on the cached objects.
5021 Please see the "cache" directive for a summary of differences among
5022 store_miss, send_hit, and cache directives.
5024 Unlike the "cache" directive, send_hit only supports fast acl
5025 types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5029 # apply custom Store ID mapping to some URLs
5030 acl MapMe dstdomain .c.example.com
5031 store_id_program ...
5032 store_id_access allow MapMe
5034 # but prevent caching of special responses
5035 # such as 302 redirects that cause StoreID loops
5036 acl Ordinary http_status 200-299
5037 store_miss deny MapMe !Ordinary
5039 # and do not serve any previously stored special responses
5040 # from the cache (in case they were already cached before
5041 # the above store_miss rule was in effect).
5042 send_hit deny MapMe !Ordinary
5048 DEFAULT_DOC: By default, this directive is unused and has no effect.
5049 LOC: Config.accessList.storeMiss
5051 Responses denied by this directive will not be cached (but may still
5052 be served from the cache, see send_hit). This directive has no
5053 effect on the responses it allows and on the already cached responses.
5055 Please see the "cache" directive for a summary of differences among
5056 store_miss, send_hit, and cache directives. See the
5057 send_hit directive for a usage example.
5059 Unlike the "cache" directive, store_miss only supports fast acl
5060 types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5066 LOC: Config.maxStale
5069 This option puts an upper limit on how stale content Squid
5070 will serve from the cache if cache validation fails.
5071 Can be overriden by the refresh_pattern max-stale option.
5074 NAME: refresh_pattern
5075 TYPE: refreshpattern
5079 usage: refresh_pattern [-i] regex min percent max [options]
5081 By default, regular expressions are CASE-SENSITIVE. To make
5082 them case-insensitive, use the -i option.
5084 'Min' is the time (in minutes) an object without an explicit
5085 expiry time should be considered fresh. The recommended
5086 value is 0, any higher values may cause dynamic applications
5087 to be erroneously cached unless the application designer
5088 has taken the appropriate actions.
5090 'Percent' is a percentage of the objects age (time since last
5091 modification age) an object without explicit expiry time
5092 will be considered fresh.
5094 'Max' is an upper limit on how long objects without an explicit
5095 expiry time will be considered fresh.
5097 options: override-expire
5102 ignore-must-revalidate
5109 override-expire enforces min age even if the server
5110 sent an explicit expiry time (e.g., with the
5111 Expires: header or Cache-Control: max-age). Doing this
5112 VIOLATES the HTTP standard. Enabling this feature
5113 could make you liable for problems which it causes.
5115 Note: override-expire does not enforce staleness - it only extends
5116 freshness / min. If the server returns a Expires time which
5117 is longer than your max time, Squid will still consider
5118 the object fresh for that period of time.
5120 override-lastmod enforces min age even on objects
5121 that were modified recently.
5123 reload-into-ims changes a client no-cache or ``reload''
5124 request for a cached entry into a conditional request using
5125 If-Modified-Since and/or If-None-Match headers, provided the
5126 cached entry has a Last-Modified and/or a strong ETag header.
5127 Doing this VIOLATES the HTTP standard. Enabling this feature
5128 could make you liable for problems which it causes.
5130 ignore-reload ignores a client no-cache or ``reload''
5131 header. Doing this VIOLATES the HTTP standard. Enabling
5132 this feature could make you liable for problems which
5135 ignore-no-store ignores any ``Cache-control: no-store''
5136 headers received from a server. Doing this VIOLATES
5137 the HTTP standard. Enabling this feature could make you
5138 liable for problems which it causes.
5140 ignore-must-revalidate ignores any ``Cache-Control: must-revalidate``
5141 headers received from a server. Doing this VIOLATES
5142 the HTTP standard. Enabling this feature could make you
5143 liable for problems which it causes.
5145 ignore-private ignores any ``Cache-control: private''
5146 headers received from a server. Doing this VIOLATES
5147 the HTTP standard. Enabling this feature could make you
5148 liable for problems which it causes.
5150 ignore-auth caches responses to requests with authorization,
5151 as if the originserver had sent ``Cache-control: public''
5152 in the response header. Doing this VIOLATES the HTTP standard.
5153 Enabling this feature could make you liable for problems which
5156 refresh-ims causes squid to contact the origin server
5157 when a client issues an If-Modified-Since request. This
5158 ensures that the client will receive an updated version
5159 if one is available.
5161 store-stale stores responses even if they don't have explicit
5162 freshness or a validator (i.e., Last-Modified or an ETag)
5163 present, or if they're already stale. By default, Squid will
5164 not cache such responses because they usually can't be
5165 reused. Note that such responses will be stale by default.
5167 max-stale=NN provide a maximum staleness factor. Squid won't
5168 serve objects more stale than this even if it failed to
5169 validate the object. Default: use the max_stale global limit.
5171 Basically a cached object is:
5173 FRESH if expires < now, else STALE
5175 FRESH if lm-factor < percent, else STALE
5179 The refresh_pattern lines are checked in the order listed here.
5180 The first entry which matches is used. If none of the entries
5181 match the default will be used.
5183 Note, you must uncomment all the default lines if you want
5184 to change one. The default setting is only active if none is
5190 # Add any of your own refresh_pattern entries above these.
5192 refresh_pattern ^ftp: 1440 20% 10080
5193 refresh_pattern ^gopher: 1440 0% 1440
5194 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0
5195 refresh_pattern . 0 20% 4320
5199 NAME: quick_abort_min
5203 LOC: Config.quickAbort.min
5206 NAME: quick_abort_max
5210 LOC: Config.quickAbort.max
5213 NAME: quick_abort_pct
5217 LOC: Config.quickAbort.pct
5219 The cache by default continues downloading aborted requests
5220 which are almost completed (less than 16 KB remaining). This
5221 may be undesirable on slow (e.g. SLIP) links and/or very busy
5222 caches. Impatient users may tie up file descriptors and
5223 bandwidth by repeatedly requesting and immediately aborting
5226 When the user aborts a request, Squid will check the
5227 quick_abort values to the amount of data transfered until
5230 If the transfer has less than 'quick_abort_min' KB remaining,
5231 it will finish the retrieval.
5233 If the transfer has more than 'quick_abort_max' KB remaining,
5234 it will abort the retrieval.
5236 If more than 'quick_abort_pct' of the transfer has completed,
5237 it will finish the retrieval.
5239 If you do not want any retrieval to continue after the client
5240 has aborted, set both 'quick_abort_min' and 'quick_abort_max'
5243 If you want retrievals to always continue if they are being
5244 cached set 'quick_abort_min' to '-1 KB'.
5247 NAME: read_ahead_gap
5248 COMMENT: buffer-size
5250 LOC: Config.readAheadGap
5253 The amount of data the cache will buffer ahead of what has been
5254 sent to the client when retrieving an object from another server.
5258 IFDEF: USE_HTTP_VIOLATIONS
5261 LOC: Config.negativeTtl
5264 Set the Default Time-to-Live (TTL) for failed requests.
5265 Certain types of failures (such as "connection refused" and
5266 "404 Not Found") are able to be negatively-cached for a short time.
5267 Modern web servers should provide Expires: header, however if they
5268 do not this can provide a minimum TTL.
5269 The default is not to cache errors with unknown expiry details.
5271 Note that this is different from negative caching of DNS lookups.
5273 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5274 this feature could make you liable for problems which it
5278 NAME: positive_dns_ttl
5281 LOC: Config.positiveDnsTtl
5284 Upper limit on how long Squid will cache positive DNS responses.
5285 Default is 6 hours (360 minutes). This directive must be set
5286 larger than negative_dns_ttl.
5289 NAME: negative_dns_ttl
5292 LOC: Config.negativeDnsTtl
5295 Time-to-Live (TTL) for negative caching of failed DNS lookups.
5296 This also sets the lower cache limit on positive lookups.
5297 Minimum value is 1 second, and it is not recommendable to go
5298 much below 10 seconds.
5301 NAME: range_offset_limit
5302 COMMENT: size [acl acl...]
5304 LOC: Config.rangeOffsetLimit
5307 usage: (size) [units] [[!]aclname]
5309 Sets an upper limit on how far (number of bytes) into the file
5310 a Range request may be to cause Squid to prefetch the whole file.
5311 If beyond this limit, Squid forwards the Range request as it is and
5312 the result is NOT cached.
5314 This is to stop a far ahead range request (lets say start at 17MB)
5315 from making Squid fetch the whole object up to that point before
5316 sending anything to the client.
5318 Multiple range_offset_limit lines may be specified, and they will
5319 be searched from top to bottom on each request until a match is found.
5320 The first match found will be used. If no line matches a request, the
5321 default limit of 0 bytes will be used.
5323 'size' is the limit specified as a number of units.
5325 'units' specifies whether to use bytes, KB, MB, etc.
5326 If no units are specified bytes are assumed.
5328 A size of 0 causes Squid to never fetch more than the
5329 client requested. (default)
5331 A size of 'none' causes Squid to always fetch the object from the
5332 beginning so it may cache the result. (2.0 style)
5334 'aclname' is the name of a defined ACL.
5336 NP: Using 'none' as the byte value here will override any quick_abort settings
5337 that may otherwise apply to the range request. The range request will
5338 be fully fetched from start to finish regardless of the client
5339 actions. This affects bandwidth usage.
5342 NAME: minimum_expiry_time
5345 LOC: Config.minimum_expiry_time
5348 The minimum caching time according to (Expires - Date)
5349 headers Squid honors if the object can't be revalidated.
5350 The default is 60 seconds.
5352 In reverse proxy environments it might be desirable to honor
5353 shorter object lifetimes. It is most likely better to make
5354 your server return a meaningful Last-Modified header however.
5356 In ESI environments where page fragments often have short
5357 lifetimes, this will often be best set to 0.
5360 NAME: store_avg_object_size
5364 LOC: Config.Store.avgObjectSize
5366 Average object size, used to estimate number of objects your
5367 cache can hold. The default is 13 KB.
5369 This is used to pre-seed the cache index memory allocation to
5370 reduce expensive reallocate operations while handling clients
5371 traffic. Too-large values may result in memory allocation during
5372 peak traffic, too-small values will result in wasted memory.
5374 Check the cache manager 'info' report metrics for the real
5375 object sizes seen by your Squid before tuning this.
5378 NAME: store_objects_per_bucket
5381 LOC: Config.Store.objectsPerBucket
5383 Target number of objects per bucket in the store hash table.
5384 Lowering this value increases the total number of buckets and
5385 also the storage maintenance rate. The default is 20.
5390 -----------------------------------------------------------------------------
5393 NAME: request_header_max_size
5397 LOC: Config.maxRequestHeaderSize
5399 This specifies the maximum size for HTTP headers in a request.
5400 Request headers are usually relatively small (about 512 bytes).
5401 Placing a limit on the request header size will catch certain
5402 bugs (for example with persistent connections) and possibly
5403 buffer-overflow or denial-of-service attacks.
5406 NAME: reply_header_max_size
5410 LOC: Config.maxReplyHeaderSize
5412 This specifies the maximum size for HTTP headers in a reply.
5413 Reply headers are usually relatively small (about 512 bytes).
5414 Placing a limit on the reply header size will catch certain
5415 bugs (for example with persistent connections) and possibly
5416 buffer-overflow or denial-of-service attacks.
5419 NAME: request_body_max_size
5423 DEFAULT_DOC: No limit.
5424 LOC: Config.maxRequestBodySize
5426 This specifies the maximum size for an HTTP request body.
5427 In other words, the maximum size of a PUT/POST request.
5428 A user who attempts to send a request with a body larger
5429 than this limit receives an "Invalid Request" error message.
5430 If you set this parameter to a zero (the default), there will
5431 be no limit imposed.
5433 See also client_request_buffer_max_size for an alternative
5434 limitation on client uploads which can be configured.
5437 NAME: client_request_buffer_max_size
5441 LOC: Config.maxRequestBufferSize
5443 This specifies the maximum buffer size of a client request.
5444 It prevents squid eating too much memory when somebody uploads
5448 NAME: chunked_request_body_max_size
5452 LOC: Config.maxChunkedRequestBodySize
5454 A broken or confused HTTP/1.1 client may send a chunked HTTP
5455 request to Squid. Squid does not have full support for that
5456 feature yet. To cope with such requests, Squid buffers the
5457 entire request and then dechunks request body to create a
5458 plain HTTP/1.0 request with a known content length. The plain
5459 request is then used by the rest of Squid code as usual.
5461 The option value specifies the maximum size of the buffer used
5462 to hold the request before the conversion. If the chunked
5463 request size exceeds the specified limit, the conversion
5464 fails, and the client receives an "unsupported request" error,
5465 as if dechunking was disabled.
5467 Dechunking is enabled by default. To disable conversion of
5468 chunked requests, set the maximum to zero.
5470 Request dechunking feature and this option in particular are a
5471 temporary hack. When chunking requests and responses are fully
5472 supported, there will be no need to buffer a chunked request.
5476 IFDEF: USE_HTTP_VIOLATIONS
5479 DEFAULT_DOC: Obey RFC 2616.
5480 LOC: Config.accessList.brokenPosts
5482 A list of ACL elements which, if matched, causes Squid to send
5483 an extra CRLF pair after the body of a PUT/POST request.
5485 Some HTTP servers has broken implementations of PUT/POST,
5486 and rely on an extra CRLF pair sent by some WWW clients.
5488 Quote from RFC2616 section 4.1 on this matter:
5490 Note: certain buggy HTTP/1.0 client implementations generate an
5491 extra CRLF's after a POST request. To restate what is explicitly
5492 forbidden by the BNF, an HTTP/1.1 client must not preface or follow
5493 a request with an extra CRLF.
5495 This clause only supports fast acl types.
5496 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5499 acl buggy_server url_regex ^http://....
5500 broken_posts allow buggy_server
5503 NAME: adaptation_uses_indirect_client icap_uses_indirect_client
5506 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_ADAPTATION
5508 LOC: Adaptation::Config::use_indirect_client
5510 Controls whether the indirect client IP address (instead of the direct
5511 client IP address) is passed to adaptation services.
5513 See also: follow_x_forwarded_for adaptation_send_client_ip
5517 IFDEF: USE_HTTP_VIOLATIONS
5521 LOC: Config.onoff.via
5523 If set (default), Squid will include a Via header in requests and
5524 replies as required by RFC2616.
5530 LOC: Config.onoff.ie_refresh
5533 Microsoft Internet Explorer up until version 5.5 Service
5534 Pack 1 has an issue with transparent proxies, wherein it
5535 is impossible to force a refresh. Turning this on provides
5536 a partial fix to the problem, by causing all IMS-REFRESH
5537 requests from older IE versions to check the origin server
5538 for fresh content. This reduces hit ratio by some amount
5539 (~10% in my experience), but allows users to actually get
5540 fresh content when they want it. Note because Squid
5541 cannot tell if the user is using 5.5 or 5.5SP1, the behavior
5542 of 5.5 is unchanged from old versions of Squid (i.e. a
5543 forced refresh is impossible). Newer versions of IE will,
5544 hopefully, continue to have the new behavior and will be
5545 handled based on that assumption. This option defaults to
5546 the old Squid behavior, which is better for hit ratios but
5547 worse for clients using IE, if they need to be able to
5548 force fresh content.
5551 NAME: vary_ignore_expire
5554 LOC: Config.onoff.vary_ignore_expire
5557 Many HTTP servers supporting Vary gives such objects
5558 immediate expiry time with no cache-control header
5559 when requested by a HTTP/1.0 client. This option
5560 enables Squid to ignore such expiry times until
5561 HTTP/1.1 is fully implemented.
5563 WARNING: If turned on this may eventually cause some
5564 varying objects not intended for caching to get cached.
5567 NAME: request_entities
5569 LOC: Config.onoff.request_entities
5572 Squid defaults to deny GET and HEAD requests with request entities,
5573 as the meaning of such requests are undefined in the HTTP standard
5574 even if not explicitly forbidden.
5576 Set this directive to on if you have clients which insists
5577 on sending request entities in GET or HEAD requests. But be warned
5578 that there is server software (both proxies and web servers) which
5579 can fail to properly process this kind of request which may make you
5580 vulnerable to cache pollution attacks if enabled.
5583 NAME: request_header_access
5584 IFDEF: USE_HTTP_VIOLATIONS
5585 TYPE: http_header_access
5586 LOC: Config.request_header_access
5588 DEFAULT_DOC: No limits.
5590 Usage: request_header_access header_name allow|deny [!]aclname ...
5592 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5593 this feature could make you liable for problems which it
5596 This option replaces the old 'anonymize_headers' and the
5597 older 'http_anonymizer' option with something that is much
5598 more configurable. A list of ACLs for each header name allows
5599 removal of specific header fields under specific conditions.
5601 This option only applies to outgoing HTTP request headers (i.e.,
5602 headers sent by Squid to the next HTTP hop such as a cache peer
5603 or an origin server). The option has no effect during cache hit
5604 detection. The equivalent adaptation vectoring point in ICAP
5605 terminology is post-cache REQMOD.
5607 The option is applied to individual outgoing request header
5608 fields. For each request header field F, Squid uses the first
5609 qualifying sets of request_header_access rules:
5611 1. Rules with header_name equal to F's name.
5612 2. Rules with header_name 'Other', provided F's name is not
5613 on the hard-coded list of commonly used HTTP header names.
5614 3. Rules with header_name 'All'.
5616 Within that qualifying rule set, rule ACLs are checked as usual.
5617 If ACLs of an "allow" rule match, the header field is allowed to
5618 go through as is. If ACLs of a "deny" rule match, the header is
5619 removed and request_header_replace is then checked to identify
5620 if the removed header has a replacement. If no rules within the
5621 set have matching ACLs, the header field is left as is.
5623 For example, to achieve the same behavior as the old
5624 'http_anonymizer standard' option, you should use:
5626 request_header_access From deny all
5627 request_header_access Referer deny all
5628 request_header_access User-Agent deny all
5630 Or, to reproduce the old 'http_anonymizer paranoid' feature
5633 request_header_access Authorization allow all
5634 request_header_access Proxy-Authorization allow all
5635 request_header_access Cache-Control allow all
5636 request_header_access Content-Length allow all
5637 request_header_access Content-Type allow all
5638 request_header_access Date allow all
5639 request_header_access Host allow all
5640 request_header_access If-Modified-Since allow all
5641 request_header_access Pragma allow all
5642 request_header_access Accept allow all
5643 request_header_access Accept-Charset allow all
5644 request_header_access Accept-Encoding allow all
5645 request_header_access Accept-Language allow all
5646 request_header_access Connection allow all
5647 request_header_access All deny all
5649 HTTP reply headers are controlled with the reply_header_access directive.
5651 By default, all headers are allowed (no anonymizing is performed).
5654 NAME: reply_header_access
5655 IFDEF: USE_HTTP_VIOLATIONS
5656 TYPE: http_header_access
5657 LOC: Config.reply_header_access
5659 DEFAULT_DOC: No limits.
5661 Usage: reply_header_access header_name allow|deny [!]aclname ...
5663 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5664 this feature could make you liable for problems which it
5667 This option only applies to reply headers, i.e., from the
5668 server to the client.
5670 This is the same as request_header_access, but in the other
5671 direction. Please see request_header_access for detailed
5674 For example, to achieve the same behavior as the old
5675 'http_anonymizer standard' option, you should use:
5677 reply_header_access Server deny all
5678 reply_header_access WWW-Authenticate deny all
5679 reply_header_access Link deny all
5681 Or, to reproduce the old 'http_anonymizer paranoid' feature
5684 reply_header_access Allow allow all
5685 reply_header_access WWW-Authenticate allow all
5686 reply_header_access Proxy-Authenticate allow all
5687 reply_header_access Cache-Control allow all
5688 reply_header_access Content-Encoding allow all
5689 reply_header_access Content-Length allow all
5690 reply_header_access Content-Type allow all
5691 reply_header_access Date allow all
5692 reply_header_access Expires allow all
5693 reply_header_access Last-Modified allow all
5694 reply_header_access Location allow all
5695 reply_header_access Pragma allow all
5696 reply_header_access Content-Language allow all
5697 reply_header_access Retry-After allow all
5698 reply_header_access Title allow all
5699 reply_header_access Content-Disposition allow all
5700 reply_header_access Connection allow all
5701 reply_header_access All deny all
5703 HTTP request headers are controlled with the request_header_access directive.
5705 By default, all headers are allowed (no anonymizing is
5709 NAME: request_header_replace header_replace
5710 IFDEF: USE_HTTP_VIOLATIONS
5711 TYPE: http_header_replace
5712 LOC: Config.request_header_access
5715 Usage: request_header_replace header_name message
5716 Example: request_header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
5718 This option allows you to change the contents of headers
5719 denied with request_header_access above, by replacing them
5720 with some fixed string.
5722 This only applies to request headers, not reply headers.
5724 By default, headers are removed if denied.
5727 NAME: reply_header_replace
5728 IFDEF: USE_HTTP_VIOLATIONS
5729 TYPE: http_header_replace
5730 LOC: Config.reply_header_access
5733 Usage: reply_header_replace header_name message
5734 Example: reply_header_replace Server Foo/1.0
5736 This option allows you to change the contents of headers
5737 denied with reply_header_access above, by replacing them
5738 with some fixed string.
5740 This only applies to reply headers, not request headers.
5742 By default, headers are removed if denied.
5745 NAME: request_header_add
5746 TYPE: HeaderWithAclList
5747 LOC: Config.request_header_add
5750 Usage: request_header_add field-name field-value acl1 [acl2] ...
5751 Example: request_header_add X-Client-CA "CA=%ssl::>cert_issuer" all
5753 This option adds header fields to outgoing HTTP requests (i.e.,
5754 request headers sent by Squid to the next HTTP hop such as a
5755 cache peer or an origin server). The option has no effect during
5756 cache hit detection. The equivalent adaptation vectoring point
5757 in ICAP terminology is post-cache REQMOD.
5759 Field-name is a token specifying an HTTP header name. If a
5760 standard HTTP header name is used, Squid does not check whether
5761 the new header conflicts with any existing headers or violates
5762 HTTP rules. If the request to be modified already contains a
5763 field with the same name, the old field is preserved but the
5764 header field values are not merged.
5766 Field-value is either a token or a quoted string. If quoted
5767 string format is used, then the surrounding quotes are removed
5768 while escape sequences and %macros are processed.
5770 In theory, all of the logformat codes can be used as %macros.
5771 However, unlike logging (which happens at the very end of
5772 transaction lifetime), the transaction may not yet have enough
5773 information to expand a macro when the new header value is needed.
5774 And some information may already be available to Squid but not yet
5775 committed where the macro expansion code can access it (report
5776 such instances!). The macro will be expanded into a single dash
5777 ('-') in such cases. Not all macros have been tested.
5779 One or more Squid ACLs may be specified to restrict header
5780 injection to matching requests. As always in squid.conf, all
5781 ACLs in an option ACL list must be satisfied for the insertion
5782 to happen. The request_header_add option supports fast ACLs
5791 This option used to log custom information about the master
5792 transaction. For example, an admin may configure Squid to log
5793 which "user group" the transaction belongs to, where "user group"
5794 will be determined based on a set of ACLs and not [just]
5795 authentication information.
5796 Values of key/value pairs can be logged using %{key}note macros:
5798 note key value acl ...
5799 logformat myFormat ... %{key}note ...
5802 NAME: relaxed_header_parser
5803 COMMENT: on|off|warn
5805 LOC: Config.onoff.relaxed_header_parser
5808 In the default "on" setting Squid accepts certain forms
5809 of non-compliant HTTP messages where it is unambiguous
5810 what the sending application intended even if the message
5811 is not correctly formatted. The messages is then normalized
5812 to the correct form when forwarded by Squid.
5814 If set to "warn" then a warning will be emitted in cache.log
5815 each time such HTTP error is encountered.
5817 If set to "off" then such HTTP errors will cause the request
5818 or response to be rejected.
5821 NAME: collapsed_forwarding
5824 LOC: Config.onoff.collapsed_forwarding
5827 This option controls whether Squid is allowed to merge multiple
5828 potentially cachable requests for the same URI before Squid knows
5829 whether the response is going to be cachable.
5831 This feature is disabled by default: Enabling collapsed forwarding
5832 needlessly delays forwarding requests that look cachable (when they are
5833 collapsed) but then need to be forwarded individually anyway because
5834 they end up being for uncachable content. However, in some cases, such
5835 as accelleration of highly cachable content with periodic or groupped
5836 expiration times, the gains from collapsing [large volumes of
5837 simultenous refresh requests] outweigh losses from such delays.
5842 -----------------------------------------------------------------------------
5845 NAME: forward_timeout
5848 LOC: Config.Timeout.forward
5851 This parameter specifies how long Squid should at most attempt in
5852 finding a forwarding path for the request before giving up.
5855 NAME: connect_timeout
5858 LOC: Config.Timeout.connect
5861 This parameter specifies how long to wait for the TCP connect to
5862 the requested server or peer to complete before Squid should
5863 attempt to find another path where to forward the request.
5866 NAME: peer_connect_timeout
5869 LOC: Config.Timeout.peer_connect
5872 This parameter specifies how long to wait for a pending TCP
5873 connection to a peer cache. The default is 30 seconds. You
5874 may also set different timeout values for individual neighbors
5875 with the 'connect-timeout' option on a 'cache_peer' line.
5881 LOC: Config.Timeout.read
5884 The read_timeout is applied on server-side connections. After
5885 each successful read(), the timeout will be extended by this
5886 amount. If no data is read again after this amount of time,
5887 the request is aborted and logged with ERR_READ_TIMEOUT. The
5888 default is 15 minutes.
5894 LOC: Config.Timeout.write
5897 This timeout is tracked for all connections that have data
5898 available for writing and are waiting for the socket to become
5899 ready. After each successful write, the timeout is extended by
5900 the configured amount. If Squid has data to write but the
5901 connection is not ready for the configured duration, the
5902 transaction associated with the connection is terminated. The
5903 default is 15 minutes.
5906 NAME: request_timeout
5908 LOC: Config.Timeout.request
5911 How long to wait for complete HTTP request headers after initial
5912 connection establishment.
5915 NAME: client_idle_pconn_timeout persistent_request_timeout
5917 LOC: Config.Timeout.clientIdlePconn
5920 How long to wait for the next HTTP request on a persistent
5921 client connection after the previous request completes.
5924 NAME: client_lifetime
5927 LOC: Config.Timeout.lifetime
5930 The maximum amount of time a client (browser) is allowed to
5931 remain connected to the cache process. This protects the Cache
5932 from having a lot of sockets (and hence file descriptors) tied up
5933 in a CLOSE_WAIT state from remote clients that go away without
5934 properly shutting down (either because of a network failure or
5935 because of a poor client implementation). The default is one
5938 NOTE: The default value is intended to be much larger than any
5939 client would ever need to be connected to your cache. You
5940 should probably change client_lifetime only as a last resort.
5941 If you seem to have many client connections tying up
5942 filedescriptors, we recommend first tuning the read_timeout,
5943 request_timeout, persistent_request_timeout and quick_abort values.
5946 NAME: half_closed_clients
5948 LOC: Config.onoff.half_closed_clients
5951 Some clients may shutdown the sending side of their TCP
5952 connections, while leaving their receiving sides open. Sometimes,
5953 Squid can not tell the difference between a half-closed and a
5954 fully-closed TCP connection.
5956 By default, Squid will immediately close client connections when
5957 read(2) returns "no more data to read."
5959 Change this option to 'on' and Squid will keep open connections
5960 until a read(2) or write(2) on the socket returns an error.
5961 This may show some benefits for reverse proxies. But if not
5962 it is recommended to leave OFF.
5965 NAME: server_idle_pconn_timeout pconn_timeout
5967 LOC: Config.Timeout.serverIdlePconn
5970 Timeout for idle persistent connections to servers and other
5977 LOC: Ident::TheConfig.timeout
5980 Maximum time to wait for IDENT lookups to complete.
5982 If this is too high, and you enabled IDENT lookups from untrusted
5983 users, you might be susceptible to denial-of-service by having
5984 many ident requests going at once.
5987 NAME: shutdown_lifetime
5990 LOC: Config.shutdownLifetime
5993 When SIGTERM or SIGHUP is received, the cache is put into
5994 "shutdown pending" mode until all active sockets are closed.
5995 This value is the lifetime to set for all open descriptors
5996 during shutdown mode. Any active clients after this many
5997 seconds will receive a 'timeout' message.
6001 ADMINISTRATIVE PARAMETERS
6002 -----------------------------------------------------------------------------
6008 LOC: Config.adminEmail
6010 Email-address of local cache manager who will receive
6011 mail if the cache dies. The default is "webmaster".
6017 LOC: Config.EmailFrom
6019 From: email-address for mail sent when the cache dies.
6020 The default is to use 'squid@unique_hostname'.
6022 See also: unique_hostname directive.
6028 LOC: Config.EmailProgram
6030 Email program used to send mail if the cache dies.
6031 The default is "mail". The specified program must comply
6032 with the standard Unix mail syntax:
6033 mail-program recipient < mailfile
6035 Optional command line options can be specified.
6038 NAME: cache_effective_user
6040 DEFAULT: @DEFAULT_CACHE_EFFECTIVE_USER@
6041 LOC: Config.effectiveUser
6043 If you start Squid as root, it will change its effective/real
6044 UID/GID to the user specified below. The default is to change
6045 to UID of @DEFAULT_CACHE_EFFECTIVE_USER@.
6046 see also; cache_effective_group
6049 NAME: cache_effective_group
6052 DEFAULT_DOC: Use system group memberships of the cache_effective_user account
6053 LOC: Config.effectiveGroup
6055 Squid sets the GID to the effective user's default group ID
6056 (taken from the password file) and supplementary group list
6057 from the groups membership.
6059 If you want Squid to run with a specific GID regardless of
6060 the group memberships of the effective user then set this
6061 to the group (or GID) you want Squid to run as. When set
6062 all other group privileges of the effective user are ignored
6063 and only this GID is effective. If Squid is not started as
6064 root the user starting Squid MUST be member of the specified
6067 This option is not recommended by the Squid Team.
6068 Our preference is for administrators to configure a secure
6069 user account for squid with UID/GID matching system policies.
6072 NAME: httpd_suppress_version_string
6076 LOC: Config.onoff.httpd_suppress_version_string
6078 Suppress Squid version string info in HTTP headers and HTML error pages.
6081 NAME: visible_hostname
6083 LOC: Config.visibleHostname
6085 DEFAULT_DOC: Automatically detect the system host name
6087 If you want to present a special hostname in error messages, etc,
6088 define this. Otherwise, the return value of gethostname()
6089 will be used. If you have multiple caches in a cluster and
6090 get errors about IP-forwarding you must set them to have individual
6091 names with this setting.
6094 NAME: unique_hostname
6096 LOC: Config.uniqueHostname
6098 DEFAULT_DOC: Copy the value from visible_hostname
6100 If you want to have multiple machines with the same
6101 'visible_hostname' you must give each machine a different
6102 'unique_hostname' so forwarding loops can be detected.
6105 NAME: hostname_aliases
6107 LOC: Config.hostnameAliases
6110 A list of other DNS names your cache has.
6118 Minimum umask which should be enforced while the proxy
6119 is running, in addition to the umask set at startup.
6121 For a traditional octal representation of umasks, start
6126 OPTIONS FOR THE CACHE REGISTRATION SERVICE
6127 -----------------------------------------------------------------------------
6129 This section contains parameters for the (optional) cache
6130 announcement service. This service is provided to help
6131 cache administrators locate one another in order to join or
6132 create cache hierarchies.
6134 An 'announcement' message is sent (via UDP) to the registration
6135 service by Squid. By default, the announcement message is NOT
6136 SENT unless you enable it with 'announce_period' below.
6138 The announcement message includes your hostname, plus the
6139 following information from this configuration file:
6145 All current information is processed regularly and made
6146 available on the Web at http://www.ircache.net/Cache/Tracker/.
6149 NAME: announce_period
6151 LOC: Config.Announce.period
6153 DEFAULT_DOC: Announcement messages disabled.
6155 This is how frequently to send cache announcements.
6157 To enable announcing your cache, just set an announce period.
6160 announce_period 1 day
6165 DEFAULT: tracker.ircache.net
6166 LOC: Config.Announce.host
6168 Set the hostname where announce registration messages will be sent.
6170 See also announce_port and announce_file
6176 LOC: Config.Announce.file
6178 The contents of this file will be included in the announce
6179 registration messages.
6185 LOC: Config.Announce.port
6187 Set the port where announce registration messages will be sent.
6189 See also announce_host and announce_file
6193 HTTPD-ACCELERATOR OPTIONS
6194 -----------------------------------------------------------------------------
6197 NAME: httpd_accel_surrogate_id
6200 DEFAULT_DOC: visible_hostname is used if no specific ID is set.
6201 LOC: Config.Accel.surrogate_id
6203 Surrogates (http://www.esi.org/architecture_spec_1.0.html)
6204 need an identification token to allow control targeting. Because
6205 a farm of surrogates may all perform the same tasks, they may share
6206 an identification token.
6209 NAME: http_accel_surrogate_remote
6213 LOC: Config.onoff.surrogate_is_remote
6215 Remote surrogates (such as those in a CDN) honour the header
6216 "Surrogate-Control: no-store-remote".
6218 Set this to on to have squid behave as a remote surrogate.
6222 IFDEF: USE_SQUID_ESI
6223 COMMENT: libxml2|expat|custom
6225 LOC: ESIParser::Type
6228 ESI markup is not strictly XML compatible. The custom ESI parser
6229 will give higher performance, but cannot handle non ASCII character
6234 DELAY POOL PARAMETERS
6235 -----------------------------------------------------------------------------
6239 TYPE: delay_pool_count
6241 IFDEF: USE_DELAY_POOLS
6244 This represents the number of delay pools to be used. For example,
6245 if you have one class 2 delay pool and one class 3 delays pool, you
6246 have a total of 2 delay pools.
6248 See also delay_parameters, delay_class, delay_access for pool
6249 configuration details.
6253 TYPE: delay_pool_class
6255 IFDEF: USE_DELAY_POOLS
6258 This defines the class of each delay pool. There must be exactly one
6259 delay_class line for each delay pool. For example, to define two
6260 delay pools, one of class 2 and one of class 3, the settings above
6264 delay_pools 4 # 4 delay pools
6265 delay_class 1 2 # pool 1 is a class 2 pool
6266 delay_class 2 3 # pool 2 is a class 3 pool
6267 delay_class 3 4 # pool 3 is a class 4 pool
6268 delay_class 4 5 # pool 4 is a class 5 pool
6270 The delay pool classes are:
6272 class 1 Everything is limited by a single aggregate
6275 class 2 Everything is limited by a single aggregate
6276 bucket as well as an "individual" bucket chosen
6277 from bits 25 through 32 of the IPv4 address.
6279 class 3 Everything is limited by a single aggregate
6280 bucket as well as a "network" bucket chosen
6281 from bits 17 through 24 of the IP address and a
6282 "individual" bucket chosen from bits 17 through
6283 32 of the IPv4 address.
6285 class 4 Everything in a class 3 delay pool, with an
6286 additional limit on a per user basis. This
6287 only takes effect if the username is established
6288 in advance - by forcing authentication in your
6291 class 5 Requests are grouped according their tag (see
6292 external_acl's tag= reply).
6295 Each pool also requires a delay_parameters directive to configure the pool size
6296 and speed limits used whenever the pool is applied to a request. Along with
6297 a set of delay_access directives to determine when it is used.
6299 NOTE: If an IP address is a.b.c.d
6300 -> bits 25 through 32 are "d"
6301 -> bits 17 through 24 are "c"
6302 -> bits 17 through 32 are "c * 256 + d"
6304 NOTE-2: Due to the use of bitmasks in class 2,3,4 pools they only apply to
6305 IPv4 traffic. Class 1 and 5 pools may be used with IPv6 traffic.
6307 This clause only supports fast acl types.
6308 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6310 See also delay_parameters and delay_access.
6314 TYPE: delay_pool_access
6316 DEFAULT_DOC: Deny using the pool, unless allow rules exist in squid.conf for the pool.
6317 IFDEF: USE_DELAY_POOLS
6320 This is used to determine which delay pool a request falls into.
6322 delay_access is sorted per pool and the matching starts with pool 1,
6323 then pool 2, ..., and finally pool N. The first delay pool where the
6324 request is allowed is selected for the request. If it does not allow
6325 the request to any pool then the request is not delayed (default).
6327 For example, if you want some_big_clients in delay
6328 pool 1 and lotsa_little_clients in delay pool 2:
6330 delay_access 1 allow some_big_clients
6331 delay_access 1 deny all
6332 delay_access 2 allow lotsa_little_clients
6333 delay_access 2 deny all
6334 delay_access 3 allow authenticated_clients
6336 See also delay_parameters and delay_class.
6340 NAME: delay_parameters
6341 TYPE: delay_pool_rates
6343 IFDEF: USE_DELAY_POOLS
6346 This defines the parameters for a delay pool. Each delay pool has
6347 a number of "buckets" associated with it, as explained in the
6348 description of delay_class.
6350 For a class 1 delay pool, the syntax is:
6352 delay_parameters pool aggregate
6354 For a class 2 delay pool:
6356 delay_parameters pool aggregate individual
6358 For a class 3 delay pool:
6360 delay_parameters pool aggregate network individual
6362 For a class 4 delay pool:
6364 delay_parameters pool aggregate network individual user
6366 For a class 5 delay pool:
6368 delay_parameters pool tagrate
6370 The option variables are:
6372 pool a pool number - ie, a number between 1 and the
6373 number specified in delay_pools as used in
6376 aggregate the speed limit parameters for the aggregate bucket
6379 individual the speed limit parameters for the individual
6380 buckets (class 2, 3).
6382 network the speed limit parameters for the network buckets
6385 user the speed limit parameters for the user buckets
6388 tagrate the speed limit parameters for the tag buckets
6391 A pair of delay parameters is written restore/maximum, where restore is
6392 the number of bytes (not bits - modem and network speeds are usually
6393 quoted in bits) per second placed into the bucket, and maximum is the
6394 maximum number of bytes which can be in the bucket at any time.
6396 There must be one delay_parameters line for each delay pool.
6399 For example, if delay pool number 1 is a class 2 delay pool as in the
6400 above example, and is being used to strictly limit each host to 64Kbit/sec
6401 (plus overheads), with no overall limit, the line is:
6403 delay_parameters 1 -1/-1 8000/8000
6405 Note that 8 x 8000 KByte/sec -> 64Kbit/sec.
6407 Note that the figure -1 is used to represent "unlimited".
6410 And, if delay pool number 2 is a class 3 delay pool as in the above
6411 example, and you want to limit it to a total of 256Kbit/sec (strict limit)
6412 with each 8-bit network permitted 64Kbit/sec (strict limit) and each
6413 individual host permitted 4800bit/sec with a bucket maximum size of 64Kbits
6414 to permit a decent web page to be downloaded at a decent speed
6415 (if the network is not being limited due to overuse) but slow down
6416 large downloads more significantly:
6418 delay_parameters 2 32000/32000 8000/8000 600/8000
6420 Note that 8 x 32000 KByte/sec -> 256Kbit/sec.
6421 8 x 8000 KByte/sec -> 64Kbit/sec.
6422 8 x 600 Byte/sec -> 4800bit/sec.
6425 Finally, for a class 4 delay pool as in the example - each user will
6426 be limited to 128Kbits/sec no matter how many workstations they are logged into.:
6428 delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000
6431 See also delay_class and delay_access.
6435 NAME: delay_initial_bucket_level
6436 COMMENT: (percent, 0-100)
6439 IFDEF: USE_DELAY_POOLS
6440 LOC: Config.Delay.initial
6442 The initial bucket percentage is used to determine how much is put
6443 in each bucket when squid starts, is reconfigured, or first notices
6444 a host accessing it (in class 2 and class 3, individual hosts and
6445 networks only have buckets associated with them once they have been
6450 CLIENT DELAY POOL PARAMETERS
6451 -----------------------------------------------------------------------------
6454 NAME: client_delay_pools
6455 TYPE: client_delay_pool_count
6457 IFDEF: USE_DELAY_POOLS
6458 LOC: Config.ClientDelay
6460 This option specifies the number of client delay pools used. It must
6461 preceed other client_delay_* options.
6464 client_delay_pools 2
6466 See also client_delay_parameters and client_delay_access.
6469 NAME: client_delay_initial_bucket_level
6470 COMMENT: (percent, 0-no_limit)
6473 IFDEF: USE_DELAY_POOLS
6474 LOC: Config.ClientDelay.initial
6476 This option determines the initial bucket size as a percentage of
6477 max_bucket_size from client_delay_parameters. Buckets are created
6478 at the time of the "first" connection from the matching IP. Idle
6479 buckets are periodically deleted up.
6481 You can specify more than 100 percent but note that such "oversized"
6482 buckets are not refilled until their size goes down to max_bucket_size
6483 from client_delay_parameters.
6486 client_delay_initial_bucket_level 50
6489 NAME: client_delay_parameters
6490 TYPE: client_delay_pool_rates
6492 IFDEF: USE_DELAY_POOLS
6493 LOC: Config.ClientDelay
6496 This option configures client-side bandwidth limits using the
6499 client_delay_parameters pool speed_limit max_bucket_size
6501 pool is an integer ID used for client_delay_access matching.
6503 speed_limit is bytes added to the bucket per second.
6505 max_bucket_size is the maximum size of a bucket, enforced after any
6506 speed_limit additions.
6508 Please see the delay_parameters option for more information and
6512 client_delay_parameters 1 1024 2048
6513 client_delay_parameters 2 51200 16384
6515 See also client_delay_access.
6519 NAME: client_delay_access
6520 TYPE: client_delay_pool_access
6522 DEFAULT_DOC: Deny use of the pool, unless allow rules exist in squid.conf for the pool.
6523 IFDEF: USE_DELAY_POOLS
6524 LOC: Config.ClientDelay
6526 This option determines the client-side delay pool for the
6529 client_delay_access pool_ID allow|deny acl_name
6531 All client_delay_access options are checked in their pool ID
6532 order, starting with pool 1. The first checked pool with allowed
6533 request is selected for the request. If no ACL matches or there
6534 are no client_delay_access options, the request bandwidth is not
6537 The ACL-selected pool is then used to find the
6538 client_delay_parameters for the request. Client-side pools are
6539 not used to aggregate clients. Clients are always aggregated
6540 based on their source IP addresses (one bucket per source IP).
6542 This clause only supports fast acl types.
6543 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6544 Additionally, only the client TCP connection details are available.
6545 ACLs testing HTTP properties will not work.
6547 Please see delay_access for more examples.
6550 client_delay_access 1 allow low_rate_network
6551 client_delay_access 2 allow vips_network
6554 See also client_delay_parameters and client_delay_pools.
6558 WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS
6559 -----------------------------------------------------------------------------
6564 LOC: Config.Wccp.router
6566 DEFAULT_DOC: WCCP disabled.
6569 Use this option to define your WCCP ``home'' router for
6572 wccp_router supports a single WCCP(v1) router
6574 wccp2_router supports multiple WCCPv2 routers
6576 only one of the two may be used at the same time and defines
6577 which version of WCCP to use.
6581 TYPE: IpAddress_list
6582 LOC: Config.Wccp2.router
6584 DEFAULT_DOC: WCCPv2 disabled.
6587 Use this option to define your WCCP ``home'' router for
6590 wccp_router supports a single WCCP(v1) router
6592 wccp2_router supports multiple WCCPv2 routers
6594 only one of the two may be used at the same time and defines
6595 which version of WCCP to use.
6600 LOC: Config.Wccp.version
6604 This directive is only relevant if you need to set up WCCP(v1)
6605 to some very old and end-of-life Cisco routers. In all other
6606 setups it must be left unset or at the default setting.
6607 It defines an internal version in the WCCP(v1) protocol,
6608 with version 4 being the officially documented protocol.
6610 According to some users, Cisco IOS 11.2 and earlier only
6611 support WCCP version 3. If you're using that or an earlier
6612 version of IOS, you may need to change this value to 3, otherwise
6613 do not specify this parameter.
6616 NAME: wccp2_rebuild_wait
6618 LOC: Config.Wccp2.rebuildwait
6622 If this is enabled Squid will wait for the cache dir rebuild to finish
6623 before sending the first wccp2 HereIAm packet
6626 NAME: wccp2_forwarding_method
6628 LOC: Config.Wccp2.forwarding_method
6632 WCCP2 allows the setting of forwarding methods between the
6633 router/switch and the cache. Valid values are as follows:
6635 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
6636 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
6638 Currently (as of IOS 12.4) cisco routers only support GRE.
6639 Cisco switches only support the L2 redirect assignment method.
6642 NAME: wccp2_return_method
6644 LOC: Config.Wccp2.return_method
6648 WCCP2 allows the setting of return methods between the
6649 router/switch and the cache for packets that the cache
6650 decides not to handle. Valid values are as follows:
6652 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
6653 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
6655 Currently (as of IOS 12.4) cisco routers only support GRE.
6656 Cisco switches only support the L2 redirect assignment.
6658 If the "ip wccp redirect exclude in" command has been
6659 enabled on the cache interface, then it is still safe for
6660 the proxy server to use a l2 redirect method even if this
6661 option is set to GRE.
6664 NAME: wccp2_assignment_method
6666 LOC: Config.Wccp2.assignment_method
6670 WCCP2 allows the setting of methods to assign the WCCP hash
6671 Valid values are as follows:
6673 hash - Hash assignment
6674 mask - Mask assignment
6676 As a general rule, cisco routers support the hash assignment method
6677 and cisco switches support the mask assignment method.
6682 LOC: Config.Wccp2.info
6683 DEFAULT_IF_NONE: standard 0
6684 DEFAULT_DOC: Use the 'web-cache' standard service.
6687 WCCP2 allows for multiple traffic services. There are two
6688 types: "standard" and "dynamic". The standard type defines
6689 one service id - http (id 0). The dynamic service ids can be from
6690 51 to 255 inclusive. In order to use a dynamic service id
6691 one must define the type of traffic to be redirected; this is done
6692 using the wccp2_service_info option.
6694 The "standard" type does not require a wccp2_service_info option,
6695 just specifying the service id will suffice.
6697 MD5 service authentication can be enabled by adding
6698 "password=<password>" to the end of this service declaration.
6702 wccp2_service standard 0 # for the 'web-cache' standard service
6703 wccp2_service dynamic 80 # a dynamic service type which will be
6704 # fleshed out with subsequent options.
6705 wccp2_service standard 0 password=foo
6708 NAME: wccp2_service_info
6709 TYPE: wccp2_service_info
6710 LOC: Config.Wccp2.info
6714 Dynamic WCCPv2 services require further information to define the
6715 traffic you wish to have diverted.
6719 wccp2_service_info <id> protocol=<protocol> flags=<flag>,<flag>..
6720 priority=<priority> ports=<port>,<port>..
6722 The relevant WCCPv2 flags:
6723 + src_ip_hash, dst_ip_hash
6724 + source_port_hash, dst_port_hash
6725 + src_ip_alt_hash, dst_ip_alt_hash
6726 + src_port_alt_hash, dst_port_alt_hash
6729 The port list can be one to eight entries.
6733 wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source
6734 priority=240 ports=80
6736 Note: the service id must have been defined by a previous
6737 'wccp2_service dynamic <id>' entry.
6742 LOC: Config.Wccp2.weight
6746 Each cache server gets assigned a set of the destination
6747 hash proportional to their weight.
6752 LOC: Config.Wccp.address
6754 DEFAULT_DOC: Address selected by the operating system.
6757 Use this option if you require WCCPv2 to use a specific
6760 The default behavior is to not bind to any specific address.
6765 LOC: Config.Wccp2.address
6767 DEFAULT_DOC: Address selected by the operating system.
6770 Use this option if you require WCCP to use a specific
6773 The default behavior is to not bind to any specific address.
6777 PERSISTENT CONNECTION HANDLING
6778 -----------------------------------------------------------------------------
6780 Also see "pconn_timeout" in the TIMEOUTS section
6783 NAME: client_persistent_connections
6785 LOC: Config.onoff.client_pconns
6788 Persistent connection support for clients.
6789 Squid uses persistent connections (when allowed). You can use
6790 this option to disable persistent connections with clients.
6793 NAME: server_persistent_connections
6795 LOC: Config.onoff.server_pconns
6798 Persistent connection support for servers.
6799 Squid uses persistent connections (when allowed). You can use
6800 this option to disable persistent connections with servers.
6803 NAME: persistent_connection_after_error
6805 LOC: Config.onoff.error_pconns
6808 With this directive the use of persistent connections after
6809 HTTP errors can be disabled. Useful if you have clients
6810 who fail to handle errors on persistent connections proper.
6813 NAME: detect_broken_pconn
6815 LOC: Config.onoff.detect_broken_server_pconns
6818 Some servers have been found to incorrectly signal the use
6819 of HTTP/1.0 persistent connections even on replies not
6820 compatible, causing significant delays. This server problem
6821 has mostly been seen on redirects.
6823 By enabling this directive Squid attempts to detect such
6824 broken replies and automatically assume the reply is finished
6825 after 10 seconds timeout.
6829 CACHE DIGEST OPTIONS
6830 -----------------------------------------------------------------------------
6833 NAME: digest_generation
6834 IFDEF: USE_CACHE_DIGESTS
6836 LOC: Config.onoff.digest_generation
6839 This controls whether the server will generate a Cache Digest
6840 of its contents. By default, Cache Digest generation is
6841 enabled if Squid is compiled with --enable-cache-digests defined.
6844 NAME: digest_bits_per_entry
6845 IFDEF: USE_CACHE_DIGESTS
6847 LOC: Config.digest.bits_per_entry
6850 This is the number of bits of the server's Cache Digest which
6851 will be associated with the Digest entry for a given HTTP
6852 Method and URL (public key) combination. The default is 5.
6855 NAME: digest_rebuild_period
6856 IFDEF: USE_CACHE_DIGESTS
6859 LOC: Config.digest.rebuild_period
6862 This is the wait time between Cache Digest rebuilds.
6865 NAME: digest_rewrite_period
6867 IFDEF: USE_CACHE_DIGESTS
6869 LOC: Config.digest.rewrite_period
6872 This is the wait time between Cache Digest writes to
6876 NAME: digest_swapout_chunk_size
6879 IFDEF: USE_CACHE_DIGESTS
6880 LOC: Config.digest.swapout_chunk_size
6883 This is the number of bytes of the Cache Digest to write to
6884 disk at a time. It defaults to 4096 bytes (4KB), the Squid
6888 NAME: digest_rebuild_chunk_percentage
6889 COMMENT: (percent, 0-100)
6890 IFDEF: USE_CACHE_DIGESTS
6892 LOC: Config.digest.rebuild_chunk_percentage
6895 This is the percentage of the Cache Digest to be scanned at a
6896 time. By default it is set to 10% of the Cache Digest.
6901 -----------------------------------------------------------------------------
6906 LOC: Config.Port.snmp
6908 DEFAULT_DOC: SNMP disabled.
6911 The port number where Squid listens for SNMP requests. To enable
6912 SNMP support set this to a suitable port number. Port number
6913 3401 is often used for the Squid SNMP agent. By default it's
6914 set to "0" (disabled)
6922 LOC: Config.accessList.snmp
6924 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
6927 Allowing or denying access to the SNMP port.
6929 All access to the agent is denied by default.
6932 snmp_access allow|deny [!]aclname ...
6934 This clause only supports fast acl types.
6935 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6938 snmp_access allow snmppublic localhost
6939 snmp_access deny all
6942 NAME: snmp_incoming_address
6944 LOC: Config.Addrs.snmp_incoming
6946 DEFAULT_DOC: Accept SNMP packets from all machine interfaces.
6949 Just like 'udp_incoming_address', but for the SNMP port.
6951 snmp_incoming_address is used for the SNMP socket receiving
6952 messages from SNMP agents.
6954 The default snmp_incoming_address is to listen on all
6955 available network interfaces.
6958 NAME: snmp_outgoing_address
6960 LOC: Config.Addrs.snmp_outgoing
6962 DEFAULT_DOC: Use snmp_incoming_address or an address selected by the operating system.
6965 Just like 'udp_outgoing_address', but for the SNMP port.
6967 snmp_outgoing_address is used for SNMP packets returned to SNMP
6970 If snmp_outgoing_address is not set it will use the same socket
6971 as snmp_incoming_address. Only change this if you want to have
6972 SNMP replies sent using another address than where this Squid
6973 listens for SNMP queries.
6975 NOTE, snmp_incoming_address and snmp_outgoing_address can not have
6976 the same value since they both use the same port.
6981 -----------------------------------------------------------------------------
6984 NAME: icp_port udp_port
6987 DEFAULT_DOC: ICP disabled.
6988 LOC: Config.Port.icp
6990 The port number where Squid sends and receives ICP queries to
6991 and from neighbor caches. The standard UDP port for ICP is 3130.
6994 icp_port @DEFAULT_ICP_PORT@
7001 DEFAULT_DOC: HTCP disabled.
7002 LOC: Config.Port.htcp
7004 The port number where Squid sends and receives HTCP queries to
7005 and from neighbor caches. To turn it on you want to set it to
7012 NAME: log_icp_queries
7016 LOC: Config.onoff.log_udp
7018 If set, ICP queries are logged to access.log. You may wish
7019 do disable this if your ICP load is VERY high to speed things
7020 up or to simplify log analysis.
7023 NAME: udp_incoming_address
7025 LOC:Config.Addrs.udp_incoming
7027 DEFAULT_DOC: Accept packets from all machine interfaces.
7029 udp_incoming_address is used for UDP packets received from other
7032 The default behavior is to not bind to any specific address.
7034 Only change this if you want to have all UDP queries received on
7035 a specific interface/address.
7037 NOTE: udp_incoming_address is used by the ICP, HTCP, and DNS
7038 modules. Altering it will affect all of them in the same manner.
7040 see also; udp_outgoing_address
7042 NOTE, udp_incoming_address and udp_outgoing_address can not
7043 have the same value since they both use the same port.
7046 NAME: udp_outgoing_address
7048 LOC: Config.Addrs.udp_outgoing
7050 DEFAULT_DOC: Use udp_incoming_address or an address selected by the operating system.
7052 udp_outgoing_address is used for UDP packets sent out to other
7055 The default behavior is to not bind to any specific address.
7057 Instead it will use the same socket as udp_incoming_address.
7058 Only change this if you want to have UDP queries sent using another
7059 address than where this Squid listens for UDP queries from other
7062 NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS
7063 modules. Altering it will affect all of them in the same manner.
7065 see also; udp_incoming_address
7067 NOTE, udp_incoming_address and udp_outgoing_address can not
7068 have the same value since they both use the same port.
7075 LOC: Config.onoff.icp_hit_stale
7077 If you want to return ICP_HIT for stale cache objects, set this
7078 option to 'on'. If you have sibling relationships with caches
7079 in other administrative domains, this should be 'off'. If you only
7080 have sibling relationships with caches under your control,
7081 it is probably okay to set this to 'on'.
7082 If set to 'on', your siblings should use the option "allow-miss"
7083 on their cache_peer lines for connecting to you.
7086 NAME: minimum_direct_hops
7089 LOC: Config.minDirectHops
7091 If using the ICMP pinging stuff, do direct fetches for sites
7092 which are no more than this many hops away.
7095 NAME: minimum_direct_rtt
7099 LOC: Config.minDirectRtt
7101 If using the ICMP pinging stuff, do direct fetches for sites
7102 which are no more than this many rtt milliseconds away.
7108 LOC: Config.Netdb.low
7110 The low water mark for the ICMP measurement database.
7112 Note: high watermark controlled by netdb_high directive.
7114 These watermarks are counts, not percents. The defaults are
7115 (low) 900 and (high) 1000. When the high water mark is
7116 reached, database entries will be deleted until the low
7123 LOC: Config.Netdb.high
7125 The high water mark for the ICMP measurement database.
7127 Note: low watermark controlled by netdb_low directive.
7129 These watermarks are counts, not percents. The defaults are
7130 (low) 900 and (high) 1000. When the high water mark is
7131 reached, database entries will be deleted until the low
7135 NAME: netdb_ping_period
7137 LOC: Config.Netdb.period
7140 The minimum period for measuring a site. There will be at
7141 least this much delay between successive pings to the same
7142 network. The default is five minutes.
7149 LOC: Config.onoff.query_icmp
7151 If you want to ask your peers to include ICMP data in their ICP
7152 replies, enable this option.
7154 If your peer has configured Squid (during compilation) with
7155 '--enable-icmp' that peer will send ICMP pings to origin server
7156 sites of the URLs it receives. If you enable this option the
7157 ICP replies from that peer will include the ICMP data (if available).
7158 Then, when choosing a parent cache, Squid will choose the parent with
7159 the minimal RTT to the origin server. When this happens, the
7160 hierarchy field of the access.log will be
7161 "CLOSEST_PARENT_MISS". This option is off by default.
7164 NAME: test_reachability
7168 LOC: Config.onoff.test_reachability
7170 When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
7171 instead of ICP_MISS if the target host is NOT in the ICMP
7172 database, or has a zero RTT.
7175 NAME: icp_query_timeout
7178 DEFAULT_DOC: Dynamic detection.
7180 LOC: Config.Timeout.icp_query
7182 Normally Squid will automatically determine an optimal ICP
7183 query timeout value based on the round-trip-time of recent ICP
7184 queries. If you want to override the value determined by
7185 Squid, set this 'icp_query_timeout' to a non-zero value. This
7186 value is specified in MILLISECONDS, so, to use a 2-second
7187 timeout (the old default), you would write:
7189 icp_query_timeout 2000
7192 NAME: maximum_icp_query_timeout
7196 LOC: Config.Timeout.icp_query_max
7198 Normally the ICP query timeout is determined dynamically. But
7199 sometimes it can lead to very large values (say 5 seconds).
7200 Use this option to put an upper limit on the dynamic timeout
7201 value. Do NOT use this option to always use a fixed (instead
7202 of a dynamic) timeout value. To set a fixed timeout see the
7203 'icp_query_timeout' directive.
7206 NAME: minimum_icp_query_timeout
7210 LOC: Config.Timeout.icp_query_min
7212 Normally the ICP query timeout is determined dynamically. But
7213 sometimes it can lead to very small timeouts, even lower than
7214 the normal latency variance on your link due to traffic.
7215 Use this option to put an lower limit on the dynamic timeout
7216 value. Do NOT use this option to always use a fixed (instead
7217 of a dynamic) timeout value. To set a fixed timeout see the
7218 'icp_query_timeout' directive.
7221 NAME: background_ping_rate
7225 LOC: Config.backgroundPingRate
7227 Controls how often the ICP pings are sent to siblings that
7228 have background-ping set.
7232 MULTICAST ICP OPTIONS
7233 -----------------------------------------------------------------------------
7238 LOC: Config.mcast_group_list
7241 This tag specifies a list of multicast groups which your server
7242 should join to receive multicasted ICP queries.
7244 NOTE! Be very careful what you put here! Be sure you
7245 understand the difference between an ICP _query_ and an ICP
7246 _reply_. This option is to be set only if you want to RECEIVE
7247 multicast queries. Do NOT set this option to SEND multicast
7248 ICP (use cache_peer for that). ICP replies are always sent via
7249 unicast, so this option does not affect whether or not you will
7250 receive replies from multicast group members.
7252 You must be very careful to NOT use a multicast address which
7253 is already in use by another group of caches.
7255 If you are unsure about multicast, please read the Multicast
7256 chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
7258 Usage: mcast_groups 239.128.16.128 224.0.1.20
7260 By default, Squid doesn't listen on any multicast groups.
7263 NAME: mcast_miss_addr
7264 IFDEF: MULTICAST_MISS_STREAM
7266 LOC: Config.mcast_miss.addr
7268 DEFAULT_DOC: disabled.
7270 If you enable this option, every "cache miss" URL will
7271 be sent out on the specified multicast address.
7273 Do not enable this option unless you are are absolutely
7274 certain you understand what you are doing.
7277 NAME: mcast_miss_ttl
7278 IFDEF: MULTICAST_MISS_STREAM
7280 LOC: Config.mcast_miss.ttl
7283 This is the time-to-live value for packets multicasted
7284 when multicasting off cache miss URLs is enabled. By
7285 default this is set to 'site scope', i.e. 16.
7288 NAME: mcast_miss_port
7289 IFDEF: MULTICAST_MISS_STREAM
7291 LOC: Config.mcast_miss.port
7294 This is the port number to be used in conjunction with
7298 NAME: mcast_miss_encode_key
7299 IFDEF: MULTICAST_MISS_STREAM
7301 LOC: Config.mcast_miss.encode_key
7302 DEFAULT: XXXXXXXXXXXXXXXX
7304 The URLs that are sent in the multicast miss stream are
7305 encrypted. This is the encryption key.
7308 NAME: mcast_icp_query_timeout
7312 LOC: Config.Timeout.mcast_icp_query
7314 For multicast peers, Squid regularly sends out ICP "probes" to
7315 count how many other peers are listening on the given multicast
7316 address. This value specifies how long Squid should wait to
7317 count all the replies. The default is 2000 msec, or 2
7322 INTERNAL ICON OPTIONS
7323 -----------------------------------------------------------------------------
7326 NAME: icon_directory
7328 LOC: Config.icons.directory
7329 DEFAULT: @DEFAULT_ICON_DIR@
7331 Where the icons are stored. These are normally kept in
7335 NAME: global_internal_static
7337 LOC: Config.onoff.global_internal_static
7340 This directive controls is Squid should intercept all requests for
7341 /squid-internal-static/ no matter which host the URL is requesting
7342 (default on setting), or if nothing special should be done for
7343 such URLs (off setting). The purpose of this directive is to make
7344 icons etc work better in complex cache hierarchies where it may
7345 not always be possible for all corners in the cache mesh to reach
7346 the server generating a directory listing.
7349 NAME: short_icon_urls
7351 LOC: Config.icons.use_short_names
7354 If this is enabled Squid will use short URLs for icons.
7355 If disabled it will revert to the old behavior of including
7356 it's own name and port in the URL.
7358 If you run a complex cache hierarchy with a mix of Squid and
7359 other proxies you may need to disable this directive.
7364 -----------------------------------------------------------------------------
7367 NAME: error_directory
7369 LOC: Config.errorDirectory
7371 DEFAULT_DOC: Send error pages in the clients preferred language
7373 If you wish to create your own versions of the default
7374 error files to customize them to suit your company copy
7375 the error/template files to another directory and point
7378 WARNING: This option will disable multi-language support
7379 on error pages if used.
7381 The squid developers are interested in making squid available in
7382 a wide variety of languages. If you are making translations for a
7383 language that Squid does not currently provide please consider
7384 contributing your translation back to the project.
7385 http://wiki.squid-cache.org/Translations
7387 The squid developers working on translations are happy to supply drop-in
7388 translated error files in exchange for any new language contributions.
7391 NAME: error_default_language
7392 IFDEF: USE_ERR_LOCALES
7394 LOC: Config.errorDefaultLanguage
7396 DEFAULT_DOC: Generate English language pages.
7398 Set the default language which squid will send error pages in
7399 if no existing translation matches the clients language
7402 If unset (default) generic English will be used.
7404 The squid developers are interested in making squid available in
7405 a wide variety of languages. If you are interested in making
7406 translations for any language see the squid wiki for details.
7407 http://wiki.squid-cache.org/Translations
7410 NAME: error_log_languages
7411 IFDEF: USE_ERR_LOCALES
7413 LOC: Config.errorLogMissingLanguages
7416 Log to cache.log what languages users are attempting to
7417 auto-negotiate for translations.
7419 Successful negotiations are not logged. Only failures
7420 have meaning to indicate that Squid may need an upgrade
7421 of its error page translations.
7424 NAME: err_page_stylesheet
7426 LOC: Config.errorStylesheet
7427 DEFAULT: @DEFAULT_CONFIG_DIR@/errorpage.css
7429 CSS Stylesheet to pattern the display of Squid default error pages.
7431 For information on CSS see http://www.w3.org/Style/CSS/
7436 LOC: Config.errHtmlText
7439 HTML text to include in error messages. Make this a "mailto"
7440 URL to your admin address, or maybe just a link to your
7441 organizations Web page.
7443 To include this in your error messages, you must rewrite
7444 the error template files (found in the "errors" directory).
7445 Wherever you want the 'err_html_text' line to appear,
7446 insert a %L tag in the error template file.
7449 NAME: email_err_data
7452 LOC: Config.onoff.emailErrData
7455 If enabled, information about the occurred error will be
7456 included in the mailto links of the ERR pages (if %W is set)
7457 so that the email body contains the data.
7458 Syntax is <A HREF="mailto:%w%W">%w</A>
7463 LOC: Config.denyInfoList
7466 Usage: deny_info err_page_name acl
7467 or deny_info http://... acl
7468 or deny_info TCP_RESET acl
7470 This can be used to return a ERR_ page for requests which
7471 do not pass the 'http_access' rules. Squid remembers the last
7472 acl it evaluated in http_access, and if a 'deny_info' line exists
7473 for that ACL Squid returns a corresponding error page.
7475 The acl is typically the last acl on the http_access deny line which
7476 denied access. The exceptions to this rule are:
7477 - When Squid needs to request authentication credentials. It's then
7478 the first authentication related acl encountered
7479 - When none of the http_access lines matches. It's then the last
7480 acl processed on the last http_access line.
7481 - When the decision to deny access was made by an adaptation service,
7482 the acl name is the corresponding eCAP or ICAP service_name.
7484 NP: If providing your own custom error pages with error_directory
7485 you may also specify them by your custom file name:
7486 Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
7488 By defaut Squid will send "403 Forbidden". A different 4xx or 5xx
7489 may be specified by prefixing the file name with the code and a colon.
7490 e.g. 404:ERR_CUSTOM_ACCESS_DENIED
7492 Alternatively you can tell Squid to reset the TCP connection
7493 by specifying TCP_RESET.
7495 Or you can specify an error URL or URL pattern. The browsers will
7496 get redirected to the specified URL after formatting tags have
7497 been replaced. Redirect will be done with 302 or 307 according to
7498 HTTP/1.1 specs. A different 3xx code may be specified by prefixing
7499 the URL. e.g. 303:http://example.com/
7502 %a - username (if available. Password NOT included)
7505 %E - Error description
7507 %H - Request domain name
7508 %i - Client IP Address
7510 %o - Message result from external ACL helper
7511 %p - Request Port number
7512 %P - Request Protocol name
7513 %R - Request URL path
7514 %T - Timestamp in RFC 1123 format
7515 %U - Full canonical URL from client
7516 (HTTPS URLs terminate with *)
7517 %u - Full canonical URL from client
7518 %w - Admin email from squid.conf
7520 %% - Literal percent (%) code
7525 OPTIONS INFLUENCING REQUEST FORWARDING
7526 -----------------------------------------------------------------------------
7529 NAME: nonhierarchical_direct
7531 LOC: Config.onoff.nonhierarchical_direct
7534 By default, Squid will send any non-hierarchical requests
7535 (matching hierarchy_stoplist or not cacheable request type) direct
7538 When this is set to "off", Squid will prefer to send these
7539 requests to parents.
7541 Note that in most configurations, by turning this off you will only
7542 add latency to these request without any improvement in global hit
7545 This option only sets a preference. If the parent is unavailable a
7546 direct connection to the origin server may still be attempted. To
7547 completely prevent direct connections use never_direct.
7552 LOC: Config.onoff.prefer_direct
7555 Normally Squid tries to use parents for most requests. If you for some
7556 reason like it to first try going direct and only use a parent if
7557 going direct fails set this to on.
7559 By combining nonhierarchical_direct off and prefer_direct on you
7560 can set up Squid to use a parent as a backup path if going direct
7563 Note: If you want Squid to use parents for all requests see
7564 the never_direct directive. prefer_direct only modifies how Squid
7565 acts on cacheable requests.
7568 NAME: cache_miss_revalidate
7572 LOC: Config.onoff.cache_miss_revalidate
7574 Whether Squid on cache MISS will pass client revalidation requests
7575 to the server or tries to fetch new content for caching.
7576 This is useful while the cache is mostly empty to more quickly
7577 have the cache populated.
7579 When set to 'on' (default), Squid will pass all client If-* headers
7582 When set to 'off' and if the request is cacheable, Squid will
7583 remove the clients If-Modified-Since and If-None-Match headers from
7584 the request sent to the server.
7589 LOC: Config.accessList.AlwaysDirect
7591 DEFAULT_DOC: Prevent any cache_peer being used for this request.
7593 Usage: always_direct allow|deny [!]aclname ...
7595 Here you can use ACL elements to specify requests which should
7596 ALWAYS be forwarded by Squid to the origin servers without using
7597 any peers. For example, to always directly forward requests for
7598 local servers ignoring any parents or siblings you may have use
7601 acl local-servers dstdomain my.domain.net
7602 always_direct allow local-servers
7604 To always forward FTP requests directly, use
7607 always_direct allow FTP
7609 NOTE: There is a similar, but opposite option named
7610 'never_direct'. You need to be aware that "always_direct deny
7611 foo" is NOT the same thing as "never_direct allow foo". You
7612 may need to use a deny rule to exclude a more-specific case of
7613 some other rule. Example:
7615 acl local-external dstdomain external.foo.net
7616 acl local-servers dstdomain .foo.net
7617 always_direct deny local-external
7618 always_direct allow local-servers
7620 NOTE: If your goal is to make the client forward the request
7621 directly to the origin server bypassing Squid then this needs
7622 to be done in the client configuration. Squid configuration
7623 can only tell Squid how Squid should fetch the object.
7625 NOTE: This directive is not related to caching. The replies
7626 is cached as usual even if you use always_direct. To not cache
7627 the replies see the 'cache' directive.
7629 This clause supports both fast and slow acl types.
7630 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7635 LOC: Config.accessList.NeverDirect
7637 DEFAULT_DOC: Allow DNS results to be used for this request.
7639 Usage: never_direct allow|deny [!]aclname ...
7641 never_direct is the opposite of always_direct. Please read
7642 the description for always_direct if you have not already.
7644 With 'never_direct' you can use ACL elements to specify
7645 requests which should NEVER be forwarded directly to origin
7646 servers. For example, to force the use of a proxy for all
7647 requests, except those in your local domain use something like:
7649 acl local-servers dstdomain .foo.net
7650 never_direct deny local-servers
7651 never_direct allow all
7653 or if Squid is inside a firewall and there are local intranet
7654 servers inside the firewall use something like:
7656 acl local-intranet dstdomain .foo.net
7657 acl local-external dstdomain external.foo.net
7658 always_direct deny local-external
7659 always_direct allow local-intranet
7660 never_direct allow all
7662 This clause supports both fast and slow acl types.
7663 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7667 ADVANCED NETWORKING OPTIONS
7668 -----------------------------------------------------------------------------
7671 NAME: incoming_udp_average incoming_icp_average
7674 LOC: Config.comm_incoming.udp.average
7676 Heavy voodoo here. I can't even believe you are reading this.
7677 Are you crazy? Don't even think about adjusting these unless
7678 you understand the algorithms in comm_select.c first!
7681 NAME: incoming_tcp_average incoming_http_average
7684 LOC: Config.comm_incoming.tcp.average
7686 Heavy voodoo here. I can't even believe you are reading this.
7687 Are you crazy? Don't even think about adjusting these unless
7688 you understand the algorithms in comm_select.c first!
7691 NAME: incoming_dns_average
7694 LOC: Config.comm_incoming.dns.average
7696 Heavy voodoo here. I can't even believe you are reading this.
7697 Are you crazy? Don't even think about adjusting these unless
7698 you understand the algorithms in comm_select.c first!
7701 NAME: min_udp_poll_cnt min_icp_poll_cnt
7704 LOC: Config.comm_incoming.udp.min_poll
7706 Heavy voodoo here. I can't even believe you are reading this.
7707 Are you crazy? Don't even think about adjusting these unless
7708 you understand the algorithms in comm_select.c first!
7711 NAME: min_dns_poll_cnt
7714 LOC: Config.comm_incoming.dns.min_poll
7716 Heavy voodoo here. I can't even believe you are reading this.
7717 Are you crazy? Don't even think about adjusting these unless
7718 you understand the algorithms in comm_select.c first!
7721 NAME: min_tcp_poll_cnt min_http_poll_cnt
7724 LOC: Config.comm_incoming.tcp.min_poll
7726 Heavy voodoo here. I can't even believe you are reading this.
7727 Are you crazy? Don't even think about adjusting these unless
7728 you understand the algorithms in comm_select.c first!
7734 LOC: Config.accept_filter
7738 The name of an accept(2) filter to install on Squid's
7739 listen socket(s). This feature is perhaps specific to
7740 FreeBSD and requires support in the kernel.
7742 The 'httpready' filter delays delivering new connections
7743 to Squid until a full HTTP request has been received.
7744 See the accf_http(9) man page for details.
7746 The 'dataready' filter delays delivering new connections
7747 to Squid until there is some data to process.
7748 See the accf_dataready(9) man page for details.
7752 The 'data' filter delays delivering of new connections
7753 to Squid until there is some data to process by TCP_ACCEPT_DEFER.
7754 You may optionally specify a number of seconds to wait by
7755 'data=N' where N is the number of seconds. Defaults to 30
7756 if not specified. See the tcp(7) man page for details.
7759 accept_filter httpready
7764 NAME: client_ip_max_connections
7766 LOC: Config.client_ip_max_connections
7768 DEFAULT_DOC: No limit.
7770 Set an absolute limit on the number of connections a single
7771 client IP can use. Any more than this and Squid will begin to drop
7772 new connections from the client until it closes some links.
7774 Note that this is a global limit. It affects all HTTP, HTCP, Gopher and FTP
7775 connections from the client. For finer control use the ACL access controls.
7777 Requires client_db to be enabled (the default).
7779 WARNING: This may noticably slow down traffic received via external proxies
7780 or NAT devices and cause them to rebound error messages back to their clients.
7783 NAME: tcp_recv_bufsize
7787 DEFAULT_DOC: Use operating system TCP defaults.
7788 LOC: Config.tcpRcvBufsz
7790 Size of receive buffer to set for TCP sockets. Probably just
7791 as easy to change your kernel's default.
7792 Omit from squid.conf to use the default buffer size.
7797 -----------------------------------------------------------------------------
7804 LOC: Adaptation::Icap::TheConfig.onoff
7807 If you want to enable the ICAP module support, set this to on.
7810 NAME: icap_connect_timeout
7813 LOC: Adaptation::Icap::TheConfig.connect_timeout_raw
7816 This parameter specifies how long to wait for the TCP connect to
7817 the requested ICAP server to complete before giving up and either
7818 terminating the HTTP transaction or bypassing the failure.
7820 The default for optional services is peer_connect_timeout.
7821 The default for essential services is connect_timeout.
7822 If this option is explicitly set, its value applies to all services.
7825 NAME: icap_io_timeout
7829 DEFAULT_DOC: Use read_timeout.
7830 LOC: Adaptation::Icap::TheConfig.io_timeout_raw
7833 This parameter specifies how long to wait for an I/O activity on
7834 an established, active ICAP connection before giving up and
7835 either terminating the HTTP transaction or bypassing the
7839 NAME: icap_service_failure_limit
7840 COMMENT: limit [in memory-depth time-units]
7841 TYPE: icap_service_failure_limit
7843 LOC: Adaptation::Icap::TheConfig
7846 The limit specifies the number of failures that Squid tolerates
7847 when establishing a new TCP connection with an ICAP service. If
7848 the number of failures exceeds the limit, the ICAP service is
7849 not used for new ICAP requests until it is time to refresh its
7852 A negative value disables the limit. Without the limit, an ICAP
7853 service will not be considered down due to connectivity failures
7854 between ICAP OPTIONS requests.
7856 Squid forgets ICAP service failures older than the specified
7857 value of memory-depth. The memory fading algorithm
7858 is approximate because Squid does not remember individual
7859 errors but groups them instead, splitting the option
7860 value into ten time slots of equal length.
7862 When memory-depth is 0 and by default this option has no
7863 effect on service failure expiration.
7865 Squid always forgets failures when updating service settings
7866 using an ICAP OPTIONS transaction, regardless of this option
7870 # suspend service usage after 10 failures in 5 seconds:
7871 icap_service_failure_limit 10 in 5 seconds
7874 NAME: icap_service_revival_delay
7877 LOC: Adaptation::Icap::TheConfig.service_revival_delay
7880 The delay specifies the number of seconds to wait after an ICAP
7881 OPTIONS request failure before requesting the options again. The
7882 failed ICAP service is considered "down" until fresh OPTIONS are
7885 The actual delay cannot be smaller than the hardcoded minimum
7886 delay of 30 seconds.
7889 NAME: icap_preview_enable
7893 LOC: Adaptation::Icap::TheConfig.preview_enable
7896 The ICAP Preview feature allows the ICAP server to handle the
7897 HTTP message by looking only at the beginning of the message body
7898 or even without receiving the body at all. In some environments,
7899 previews greatly speedup ICAP processing.
7901 During an ICAP OPTIONS transaction, the server may tell Squid what
7902 HTTP messages should be previewed and how big the preview should be.
7903 Squid will not use Preview if the server did not request one.
7905 To disable ICAP Preview for all ICAP services, regardless of
7906 individual ICAP server OPTIONS responses, set this option to "off".
7908 icap_preview_enable off
7911 NAME: icap_preview_size
7914 LOC: Adaptation::Icap::TheConfig.preview_size
7916 DEFAULT_DOC: No preview sent.
7918 The default size of preview data to be sent to the ICAP server.
7919 This value might be overwritten on a per server basis by OPTIONS requests.
7922 NAME: icap_206_enable
7926 LOC: Adaptation::Icap::TheConfig.allow206_enable
7929 206 (Partial Content) responses is an ICAP extension that allows the
7930 ICAP agents to optionally combine adapted and original HTTP message
7931 content. The decision to combine is postponed until the end of the
7932 ICAP response. Squid supports Partial Content extension by default.
7934 Activation of the Partial Content extension is negotiated with each
7935 ICAP service during OPTIONS exchange. Most ICAP servers should handle
7936 negotation correctly even if they do not support the extension, but
7937 some might fail. To disable Partial Content support for all ICAP
7938 services and to avoid any negotiation, set this option to "off".
7944 NAME: icap_default_options_ttl
7947 LOC: Adaptation::Icap::TheConfig.default_options_ttl
7950 The default TTL value for ICAP OPTIONS responses that don't have
7951 an Options-TTL header.
7954 NAME: icap_persistent_connections
7958 LOC: Adaptation::Icap::TheConfig.reuse_connections
7961 Whether or not Squid should use persistent connections to
7965 NAME: adaptation_send_client_ip icap_send_client_ip
7967 IFDEF: USE_ADAPTATION
7969 LOC: Adaptation::Config::send_client_ip
7972 If enabled, Squid shares HTTP client IP information with adaptation
7973 services. For ICAP, Squid adds the X-Client-IP header to ICAP requests.
7974 For eCAP, Squid sets the libecap::metaClientIp transaction option.
7976 See also: adaptation_uses_indirect_client
7979 NAME: adaptation_send_username icap_send_client_username
7981 IFDEF: USE_ADAPTATION
7983 LOC: Adaptation::Config::send_username
7986 This sends authenticated HTTP client username (if available) to
7987 the adaptation service.
7989 For ICAP, the username value is encoded based on the
7990 icap_client_username_encode option and is sent using the header
7991 specified by the icap_client_username_header option.
7994 NAME: icap_client_username_header
7997 LOC: Adaptation::Icap::TheConfig.client_username_header
7998 DEFAULT: X-Client-Username
8000 ICAP request header name to use for adaptation_send_username.
8003 NAME: icap_client_username_encode
8007 LOC: Adaptation::Icap::TheConfig.client_username_encode
8010 Whether to base64 encode the authenticated client username.
8014 TYPE: icap_service_type
8016 LOC: Adaptation::Icap::TheConfig
8019 Defines a single ICAP service using the following format:
8021 icap_service id vectoring_point uri [option ...]
8024 an opaque identifier or name which is used to direct traffic to
8025 this specific service. Must be unique among all adaptation
8026 services in squid.conf.
8028 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
8029 This specifies at which point of transaction processing the
8030 ICAP service should be activated. *_postcache vectoring points
8031 are not yet supported.
8033 uri: icap://servername:port/servicepath
8034 ICAP server and service location.
8036 ICAP does not allow a single service to handle both REQMOD and RESPMOD
8037 transactions. Squid does not enforce that requirement. You can specify
8038 services with the same service_url and different vectoring_points. You
8039 can even specify multiple identical services as long as their
8040 service_names differ.
8042 To activate a service, use the adaptation_access directive. To group
8043 services, use adaptation_service_chain and adaptation_service_set.
8045 Service options are separated by white space. ICAP services support
8046 the following name=value options:
8049 If set to 'on' or '1', the ICAP service is treated as
8050 optional. If the service cannot be reached or malfunctions,
8051 Squid will try to ignore any errors and process the message as
8052 if the service was not enabled. No all ICAP errors can be
8053 bypassed. If set to 0, the ICAP service is treated as
8054 essential and all ICAP errors will result in an error page
8055 returned to the HTTP client.
8057 Bypass is off by default: services are treated as essential.
8060 If set to 'on' or '1', the ICAP service is allowed to
8061 dynamically change the current message adaptation plan by
8062 returning a chain of services to be used next. The services
8063 are specified using the X-Next-Services ICAP response header
8064 value, formatted as a comma-separated list of service names.
8065 Each named service should be configured in squid.conf. Other
8066 services are ignored. An empty X-Next-Services value results
8067 in an empty plan which ends the current adaptation.
8069 Dynamic adaptation plan may cross or cover multiple supported
8070 vectoring points in their natural processing order.
8072 Routing is not allowed by default: the ICAP X-Next-Services
8073 response header is ignored.
8076 Only has effect on split-stack systems. The default on those systems
8077 is to use IPv4-only connections. When set to 'on' this option will
8078 make Squid use IPv6-only connections to contact this ICAP service.
8080 on-overload=block|bypass|wait|force
8081 If the service Max-Connections limit has been reached, do
8082 one of the following for each new ICAP transaction:
8083 * block: send an HTTP error response to the client
8084 * bypass: ignore the "over-connected" ICAP service
8085 * wait: wait (in a FIFO queue) for an ICAP connection slot
8086 * force: proceed, ignoring the Max-Connections limit
8088 In SMP mode with N workers, each worker assumes the service
8089 connection limit is Max-Connections/N, even though not all
8090 workers may use a given service.
8092 The default value is "bypass" if service is bypassable,
8093 otherwise it is set to "wait".
8097 Use the given number as the Max-Connections limit, regardless
8098 of the Max-Connections value given by the service, if any.
8100 Older icap_service format without optional named parameters is
8101 deprecated but supported for backward compatibility.
8104 icap_service svcBlocker reqmod_precache icap://icap1.mydomain.net:1344/reqmod bypass=0
8105 icap_service svcLogger reqmod_precache icap://icap2.mydomain.net:1344/respmod routing=on
8109 TYPE: icap_class_type
8114 This deprecated option was documented to define an ICAP service
8115 chain, even though it actually defined a set of similar, redundant
8116 services, and the chains were not supported.
8118 To define a set of redundant services, please use the
8119 adaptation_service_set directive. For service chains, use
8120 adaptation_service_chain.
8124 TYPE: icap_access_type
8129 This option is deprecated. Please use adaptation_access, which
8130 has the same ICAP functionality, but comes with better
8131 documentation, and eCAP support.
8136 -----------------------------------------------------------------------------
8143 LOC: Adaptation::Ecap::TheConfig.onoff
8146 Controls whether eCAP support is enabled.
8150 TYPE: ecap_service_type
8152 LOC: Adaptation::Ecap::TheConfig
8155 Defines a single eCAP service
8157 ecap_service id vectoring_point uri [option ...]
8160 an opaque identifier or name which is used to direct traffic to
8161 this specific service. Must be unique among all adaptation
8162 services in squid.conf.
8164 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
8165 This specifies at which point of transaction processing the
8166 eCAP service should be activated. *_postcache vectoring points
8167 are not yet supported.
8169 uri: ecap://vendor/service_name?custom&cgi=style¶meters=optional
8170 Squid uses the eCAP service URI to match this configuration
8171 line with one of the dynamically loaded services. Each loaded
8172 eCAP service must have a unique URI. Obtain the right URI from
8173 the service provider.
8175 To activate a service, use the adaptation_access directive. To group
8176 services, use adaptation_service_chain and adaptation_service_set.
8178 Service options are separated by white space. eCAP services support
8179 the following name=value options:
8182 If set to 'on' or '1', the eCAP service is treated as optional.
8183 If the service cannot be reached or malfunctions, Squid will try
8184 to ignore any errors and process the message as if the service
8185 was not enabled. No all eCAP errors can be bypassed.
8186 If set to 'off' or '0', the eCAP service is treated as essential
8187 and all eCAP errors will result in an error page returned to the
8190 Bypass is off by default: services are treated as essential.
8193 If set to 'on' or '1', the eCAP service is allowed to
8194 dynamically change the current message adaptation plan by
8195 returning a chain of services to be used next.
8197 Dynamic adaptation plan may cross or cover multiple supported
8198 vectoring points in their natural processing order.
8200 Routing is not allowed by default.
8202 Older ecap_service format without optional named parameters is
8203 deprecated but supported for backward compatibility.
8207 ecap_service s1 reqmod_precache ecap://filters.R.us/leakDetector?on_error=block bypass=off
8208 ecap_service s2 respmod_precache ecap://filters.R.us/virusFilter config=/etc/vf.cfg bypass=on
8211 NAME: loadable_modules
8213 IFDEF: USE_LOADABLE_MODULES
8214 LOC: Config.loadable_module_names
8217 Instructs Squid to load the specified dynamic module(s) or activate
8218 preloaded module(s).
8220 loadable_modules @DEFAULT_PREFIX@/lib/MinimalAdapter.so
8224 MESSAGE ADAPTATION OPTIONS
8225 -----------------------------------------------------------------------------
8228 NAME: adaptation_service_set
8229 TYPE: adaptation_service_set_type
8230 IFDEF: USE_ADAPTATION
8235 Configures an ordered set of similar, redundant services. This is
8236 useful when hot standby or backup adaptation servers are available.
8238 adaptation_service_set set_name service_name1 service_name2 ...
8240 The named services are used in the set declaration order. The first
8241 applicable adaptation service from the set is used first. The next
8242 applicable service is tried if and only if the transaction with the
8243 previous service fails and the message waiting to be adapted is still
8246 When adaptation starts, broken services are ignored as if they were
8247 not a part of the set. A broken service is a down optional service.
8249 The services in a set must be attached to the same vectoring point
8250 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
8252 If all services in a set are optional then adaptation failures are
8253 bypassable. If all services in the set are essential, then a
8254 transaction failure with one service may still be retried using
8255 another service from the set, but when all services fail, the master
8256 transaction fails as well.
8258 A set may contain a mix of optional and essential services, but that
8259 is likely to lead to surprising results because broken services become
8260 ignored (see above), making previously bypassable failures fatal.
8261 Technically, it is the bypassability of the last failed service that
8264 See also: adaptation_access adaptation_service_chain
8267 adaptation_service_set svcBlocker urlFilterPrimary urlFilterBackup
8268 adaptation service_set svcLogger loggerLocal loggerRemote
8271 NAME: adaptation_service_chain
8272 TYPE: adaptation_service_chain_type
8273 IFDEF: USE_ADAPTATION
8278 Configures a list of complementary services that will be applied
8279 one-by-one, forming an adaptation chain or pipeline. This is useful
8280 when Squid must perform different adaptations on the same message.
8282 adaptation_service_chain chain_name service_name1 svc_name2 ...
8284 The named services are used in the chain declaration order. The first
8285 applicable adaptation service from the chain is used first. The next
8286 applicable service is applied to the successful adaptation results of
8287 the previous service in the chain.
8289 When adaptation starts, broken services are ignored as if they were
8290 not a part of the chain. A broken service is a down optional service.
8292 Request satisfaction terminates the adaptation chain because Squid
8293 does not currently allow declaration of RESPMOD services at the
8294 "reqmod_precache" vectoring point (see icap_service or ecap_service).
8296 The services in a chain must be attached to the same vectoring point
8297 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
8299 A chain may contain a mix of optional and essential services. If an
8300 essential adaptation fails (or the failure cannot be bypassed for
8301 other reasons), the master transaction fails. Otherwise, the failure
8302 is bypassed as if the failed adaptation service was not in the chain.
8304 See also: adaptation_access adaptation_service_set
8307 adaptation_service_chain svcRequest requestLogger urlFilter leakDetector
8310 NAME: adaptation_access
8311 TYPE: adaptation_access_type
8312 IFDEF: USE_ADAPTATION
8315 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
8317 Sends an HTTP transaction to an ICAP or eCAP adaptation service.
8319 adaptation_access service_name allow|deny [!]aclname...
8320 adaptation_access set_name allow|deny [!]aclname...
8322 At each supported vectoring point, the adaptation_access
8323 statements are processed in the order they appear in this
8324 configuration file. Statements pointing to the following services
8325 are ignored (i.e., skipped without checking their ACL):
8327 - services serving different vectoring points
8328 - "broken-but-bypassable" services
8329 - "up" services configured to ignore such transactions
8330 (e.g., based on the ICAP Transfer-Ignore header).
8332 When a set_name is used, all services in the set are checked
8333 using the same rules, to find the first applicable one. See
8334 adaptation_service_set for details.
8336 If an access list is checked and there is a match, the
8337 processing stops: For an "allow" rule, the corresponding
8338 adaptation service is used for the transaction. For a "deny"
8339 rule, no adaptation service is activated.
8341 It is currently not possible to apply more than one adaptation
8342 service at the same vectoring point to the same HTTP transaction.
8344 See also: icap_service and ecap_service
8347 adaptation_access service_1 allow all
8350 NAME: adaptation_service_iteration_limit
8352 IFDEF: USE_ADAPTATION
8353 LOC: Adaptation::Config::service_iteration_limit
8356 Limits the number of iterations allowed when applying adaptation
8357 services to a message. If your longest adaptation set or chain
8358 may have more than 16 services, increase the limit beyond its
8359 default value of 16. If detecting infinite iteration loops sooner
8360 is critical, make the iteration limit match the actual number
8361 of services in your longest adaptation set or chain.
8363 Infinite adaptation loops are most likely with routing services.
8365 See also: icap_service routing=1
8368 NAME: adaptation_masterx_shared_names
8370 IFDEF: USE_ADAPTATION
8371 LOC: Adaptation::Config::masterx_shared_name
8374 For each master transaction (i.e., the HTTP request and response
8375 sequence, including all related ICAP and eCAP exchanges), Squid
8376 maintains a table of metadata. The table entries are (name, value)
8377 pairs shared among eCAP and ICAP exchanges. The table is destroyed
8378 with the master transaction.
8380 This option specifies the table entry names that Squid must accept
8381 from and forward to the adaptation transactions.
8383 An ICAP REQMOD or RESPMOD transaction may set an entry in the
8384 shared table by returning an ICAP header field with a name
8385 specified in adaptation_masterx_shared_names.
8387 An eCAP REQMOD or RESPMOD transaction may set an entry in the
8388 shared table by implementing the libecap::visitEachOption() API
8389 to provide an option with a name specified in
8390 adaptation_masterx_shared_names.
8392 Squid will store and forward the set entry to subsequent adaptation
8393 transactions within the same master transaction scope.
8395 Only one shared entry name is supported at this time.
8398 # share authentication information among ICAP services
8399 adaptation_masterx_shared_names X-Subscriber-ID
8402 NAME: adaptation_meta
8404 IFDEF: USE_ADAPTATION
8405 LOC: Adaptation::Config::metaHeaders
8408 This option allows Squid administrator to add custom ICAP request
8409 headers or eCAP options to Squid ICAP requests or eCAP transactions.
8410 Use it to pass custom authentication tokens and other
8411 transaction-state related meta information to an ICAP/eCAP service.
8413 The addition of a meta header is ACL-driven:
8414 adaptation_meta name value [!]aclname ...
8416 Processing for a given header name stops after the first ACL list match.
8417 Thus, it is impossible to add two headers with the same name. If no ACL
8418 lists match for a given header name, no such header is added. For
8421 # do not debug transactions except for those that need debugging
8422 adaptation_meta X-Debug 1 needs_debugging
8424 # log all transactions except for those that must remain secret
8425 adaptation_meta X-Log 1 !keep_secret
8427 # mark transactions from users in the "G 1" group
8428 adaptation_meta X-Authenticated-Groups "G 1" authed_as_G1
8430 The "value" parameter may be a regular squid.conf token or a "double
8431 quoted string". Within the quoted string, use backslash (\) to escape
8432 any character, which is currently only useful for escaping backslashes
8433 and double quotes. For example,
8434 "this string has one backslash (\\) and two \"quotes\""
8436 Used adaptation_meta header values may be logged via %note
8437 logformat code. If multiple adaptation_meta headers with the same name
8438 are used during master transaction lifetime, the header values are
8439 logged in the order they were used and duplicate values are ignored
8440 (only the first repeated value will be logged).
8446 LOC: Adaptation::Icap::TheConfig.repeat
8447 DEFAULT_IF_NONE: deny all
8449 This ACL determines which retriable ICAP transactions are
8450 retried. Transactions that received a complete ICAP response
8451 and did not have to consume or produce HTTP bodies to receive
8452 that response are usually retriable.
8454 icap_retry allow|deny [!]aclname ...
8456 Squid automatically retries some ICAP I/O timeouts and errors
8457 due to persistent connection race conditions.
8459 See also: icap_retry_limit
8462 NAME: icap_retry_limit
8465 LOC: Adaptation::Icap::TheConfig.repeat_limit
8467 DEFAULT_DOC: No retries are allowed.
8469 Limits the number of retries allowed.
8471 Communication errors due to persistent connection race
8472 conditions are unavoidable, automatically retried, and do not
8473 count against this limit.
8475 See also: icap_retry
8481 -----------------------------------------------------------------------------
8484 NAME: check_hostnames
8487 LOC: Config.onoff.check_hostnames
8489 For security and stability reasons Squid can check
8490 hostnames for Internet standard RFC compliance. If you want
8491 Squid to perform these checks turn this directive on.
8494 NAME: allow_underscore
8497 LOC: Config.onoff.allow_underscore
8499 Underscore characters is not strictly allowed in Internet hostnames
8500 but nevertheless used by many sites. Set this to off if you want
8501 Squid to be strict about the standard.
8502 This check is performed only when check_hostnames is set to on.
8505 NAME: dns_retransmit_interval
8508 LOC: Config.Timeout.idns_retransmit
8510 Initial retransmit interval for DNS queries. The interval is
8511 doubled each time all configured DNS servers have been tried.
8517 LOC: Config.Timeout.idns_query
8519 DNS Query timeout. If no response is received to a DNS query
8520 within this time all DNS servers for the queried domain
8521 are assumed to be unavailable.
8524 NAME: dns_packet_max
8526 DEFAULT_DOC: EDNS disabled
8528 LOC: Config.dns.packet_max
8530 Maximum number of bytes packet size to advertise via EDNS.
8531 Set to "none" to disable EDNS large packet support.
8533 For legacy reasons DNS UDP replies will default to 512 bytes which
8534 is too small for many responses. EDNS provides a means for Squid to
8535 negotiate receiving larger responses back immediately without having
8536 to failover with repeat requests. Responses larger than this limit
8537 will retain the old behaviour of failover to TCP DNS.
8539 Squid has no real fixed limit internally, but allowing packet sizes
8540 over 1500 bytes requires network jumbogram support and is usually not
8543 WARNING: The RFC also indicates that some older resolvers will reply
8544 with failure of the whole request if the extension is added. Some
8545 resolvers have already been identified which will reply with mangled
8546 EDNS response on occasion. Usually in response to many-KB jumbogram
8547 sizes being advertised by Squid.
8548 Squid will currently treat these both as an unable-to-resolve domain
8549 even if it would be resolvable without EDNS.
8556 DEFAULT_DOC: Search for single-label domain names is disabled.
8557 LOC: Config.onoff.res_defnames
8559 Normally the RES_DEFNAMES resolver option is disabled
8560 (see res_init(3)). This prevents caches in a hierarchy
8561 from interpreting single-component hostnames locally. To allow
8562 Squid to handle single-component names, enable this option.
8565 NAME: dns_multicast_local
8569 DEFAULT_DOC: Search for .local and .arpa names is disabled.
8570 LOC: Config.onoff.dns_mdns
8572 When set to on, Squid sends multicast DNS lookups on the local
8573 network for domains ending in .local and .arpa.
8574 This enables local servers and devices to be contacted in an
8575 ad-hoc or zero-configuration network environment.
8578 NAME: dns_nameservers
8581 DEFAULT_DOC: Use operating system definitions
8582 LOC: Config.dns_nameservers
8584 Use this if you want to specify a list of DNS name servers
8585 (IP addresses) to use instead of those given in your
8586 /etc/resolv.conf file.
8588 On Windows platforms, if no value is specified here or in
8589 the /etc/resolv.conf file, the list of DNS name servers are
8590 taken from the Windows registry, both static and dynamic DHCP
8591 configurations are supported.
8593 Example: dns_nameservers 10.0.0.1 192.172.0.4
8598 DEFAULT: @DEFAULT_HOSTS@
8599 LOC: Config.etcHostsPath
8601 Location of the host-local IP name-address associations
8602 database. Most Operating Systems have such a file on different
8604 - Un*X & Linux: /etc/hosts
8605 - Windows NT/2000: %SystemRoot%\system32\drivers\etc\hosts
8606 (%SystemRoot% value install default is c:\winnt)
8607 - Windows XP/2003: %SystemRoot%\system32\drivers\etc\hosts
8608 (%SystemRoot% value install default is c:\windows)
8609 - Windows 9x/Me: %windir%\hosts
8610 (%windir% value is usually c:\windows)
8611 - Cygwin: /etc/hosts
8613 The file contains newline-separated definitions, in the
8614 form ip_address_in_dotted_form name [name ...] names are
8615 whitespace-separated. Lines beginning with an hash (#)
8616 character are comments.
8618 The file is checked at startup and upon configuration.
8619 If set to 'none', it won't be checked.
8620 If append_domain is used, that domain will be added to
8621 domain-local (i.e. not containing any dot character) host
8627 LOC: Config.appendDomain
8629 DEFAULT_DOC: Use operating system definitions
8631 Appends local domain name to hostnames without any dots in
8632 them. append_domain must begin with a period.
8634 Be warned there are now Internet names with no dots in
8635 them using only top-domain names, so setting this may
8636 cause some Internet sites to become unavailable.
8639 append_domain .yourdomain.com
8642 NAME: ignore_unknown_nameservers
8644 LOC: Config.onoff.ignore_unknown_nameservers
8647 By default Squid checks that DNS responses are received
8648 from the same IP addresses they are sent to. If they
8649 don't match, Squid ignores the response and writes a warning
8650 message to cache.log. You can allow responses from unknown
8651 nameservers by setting this option to 'off'.
8657 LOC: Config.dns.v4_first
8659 With the IPv6 Internet being as fast or faster than IPv4 Internet
8660 for most networks Squid prefers to contact websites over IPv6.
8662 This option reverses the order of preference to make Squid contact
8663 dual-stack websites over IPv4 first. Squid will still perform both
8664 IPv6 and IPv4 DNS lookups before connecting.
8667 This option will restrict the situations under which IPv6
8668 connectivity is used (and tested). Hiding network problems
8669 which would otherwise be detected and warned about.
8673 COMMENT: (number of entries)
8676 LOC: Config.ipcache.size
8678 Maximum number of DNS IP cache entries.
8685 LOC: Config.ipcache.low
8692 LOC: Config.ipcache.high
8694 The size, low-, and high-water marks for the IP cache.
8697 NAME: fqdncache_size
8698 COMMENT: (number of entries)
8701 LOC: Config.fqdncache.size
8703 Maximum number of FQDN cache entries.
8708 -----------------------------------------------------------------------------
8711 NAME: configuration_includes_quoted_values
8713 TYPE: configuration_includes_quoted_values
8715 LOC: ConfigParser::RecognizeQuotedValues
8717 If set, Squid will recognize each "quoted string" after a configuration
8718 directive as a single parameter. The quotes are stripped before the
8719 parameter value is interpreted or used.
8720 See "Values with spaces, quotes, and other special characters"
8721 section for more details.
8728 LOC: Config.onoff.mem_pools
8730 If set, Squid will keep pools of allocated (but unused) memory
8731 available for future use. If memory is a premium on your
8732 system and you believe your malloc library outperforms Squid
8733 routines, disable this.
8736 NAME: memory_pools_limit
8740 LOC: Config.MemPools.limit
8742 Used only with memory_pools on:
8743 memory_pools_limit 50 MB
8745 If set to a non-zero value, Squid will keep at most the specified
8746 limit of allocated (but unused) memory in memory pools. All free()
8747 requests that exceed this limit will be handled by your malloc
8748 library. Squid does not pre-allocate any memory, just safe-keeps
8749 objects that otherwise would be free()d. Thus, it is safe to set
8750 memory_pools_limit to a reasonably high value even if your
8751 configuration will use less memory.
8753 If set to none, Squid will keep all memory it can. That is, there
8754 will be no limit on the total amount of memory used for safe-keeping.
8756 To disable memory allocation optimization, do not set
8757 memory_pools_limit to 0 or none. Set memory_pools to "off" instead.
8759 An overhead for maintaining memory pools is not taken into account
8760 when the limit is checked. This overhead is close to four bytes per
8761 object kept. However, pools may actually _save_ memory because of
8762 reduced memory thrashing in your malloc library.
8766 COMMENT: on|off|transparent|truncate|delete
8769 LOC: opt_forwarded_for
8771 If set to "on", Squid will append your client's IP address
8772 in the HTTP requests it forwards. By default it looks like:
8774 X-Forwarded-For: 192.1.2.3
8776 If set to "off", it will appear as
8778 X-Forwarded-For: unknown
8780 If set to "transparent", Squid will not alter the
8781 X-Forwarded-For header in any way.
8783 If set to "delete", Squid will delete the entire
8784 X-Forwarded-For header.
8786 If set to "truncate", Squid will remove all existing
8787 X-Forwarded-For entries, and place the client IP as the sole entry.
8790 NAME: cachemgr_passwd
8791 TYPE: cachemgrpasswd
8793 DEFAULT_DOC: No password. Actions which require password are denied.
8794 LOC: Config.passwd_list
8796 Specify passwords for cachemgr operations.
8798 Usage: cachemgr_passwd password action action ...
8800 Some valid actions are (see cache manager menu for a full list):
8840 * Indicates actions which will not be performed without a
8841 valid password, others can be performed if not listed here.
8843 To disable an action, set the password to "disable".
8844 To allow performing an action without a password, set the
8847 Use the keyword "all" to set the same password for all actions.
8850 cachemgr_passwd secret shutdown
8851 cachemgr_passwd lesssssssecret info stats/objects
8852 cachemgr_passwd disable all
8859 LOC: Config.onoff.client_db
8861 If you want to disable collecting per-client statistics,
8862 turn off client_db here.
8865 NAME: refresh_all_ims
8869 LOC: Config.onoff.refresh_all_ims
8871 When you enable this option, squid will always check
8872 the origin server for an update when a client sends an
8873 If-Modified-Since request. Many browsers use IMS
8874 requests when the user requests a reload, and this
8875 ensures those clients receive the latest version.
8877 By default (off), squid may return a Not Modified response
8878 based on the age of the cached version.
8881 NAME: reload_into_ims
8882 IFDEF: USE_HTTP_VIOLATIONS
8886 LOC: Config.onoff.reload_into_ims
8888 When you enable this option, client no-cache or ``reload''
8889 requests will be changed to If-Modified-Since requests.
8890 Doing this VIOLATES the HTTP standard. Enabling this
8891 feature could make you liable for problems which it
8894 see also refresh_pattern for a more selective approach.
8897 NAME: connect_retries
8899 LOC: Config.connect_retries
8901 DEFAULT_DOC: Do not retry failed connections.
8903 This sets the maximum number of connection attempts made for each
8904 TCP connection. The connect_retries attempts must all still
8905 complete within the connection timeout period.
8907 The default is not to re-try if the first connection attempt fails.
8908 The (not recommended) maximum is 10 tries.
8910 A warning message will be generated if it is set to a too-high
8911 value and the configured value will be over-ridden.
8913 Note: These re-tries are in addition to forward_max_tries
8914 which limit how many different addresses may be tried to find
8918 NAME: retry_on_error
8920 LOC: Config.retry.onerror
8923 If set to ON Squid will automatically retry requests when
8924 receiving an error response with status 403 (Forbidden),
8925 500 (Internal Error), 501 or 503 (Service not available).
8926 Status 502 and 504 (Gateway errors) are always retried.
8928 This is mainly useful if you are in a complex cache hierarchy to
8929 work around access control errors.
8931 NOTE: This retry will attempt to find another working destination.
8932 Which is different from the server which just failed.
8935 NAME: as_whois_server
8937 LOC: Config.as_whois_server
8938 DEFAULT: whois.ra.net
8940 WHOIS server to query for AS numbers. NOTE: AS numbers are
8941 queried only when Squid starts up, not for every request.
8946 LOC: Config.onoff.offline
8949 Enable this option and Squid will never try to validate cached
8953 NAME: uri_whitespace
8954 TYPE: uri_whitespace
8955 LOC: Config.uri_whitespace
8958 What to do with requests that have whitespace characters in the
8961 strip: The whitespace characters are stripped out of the URL.
8962 This is the behavior recommended by RFC2396 and RFC3986
8963 for tolerant handling of generic URI.
8964 NOTE: This is one difference between generic URI and HTTP URLs.
8966 deny: The request is denied. The user receives an "Invalid
8968 This is the behaviour recommended by RFC2616 for safe
8969 handling of HTTP request URL.
8971 allow: The request is allowed and the URI is not changed. The
8972 whitespace characters remain in the URI. Note the
8973 whitespace is passed to redirector processes if they
8975 Note this may be considered a violation of RFC2616
8976 request parsing where whitespace is prohibited in the
8979 encode: The request is allowed and the whitespace characters are
8980 encoded according to RFC1738.
8982 chop: The request is allowed and the URI is chopped at the
8986 NOTE the current Squid implementation of encode and chop violates
8987 RFC2616 by not using a 301 redirect after altering the URL.
8992 LOC: Config.chroot_dir
8995 Specifies a directory where Squid should do a chroot() while
8996 initializing. This also causes Squid to fully drop root
8997 privileges after initializing. This means, for example, if you
8998 use a HTTP port less than 1024 and try to reconfigure, you may
8999 get an error saying that Squid can not open the port.
9002 NAME: balance_on_multiple_ip
9004 LOC: Config.onoff.balance_on_multiple_ip
9007 Modern IP resolvers in squid sort lookup results by preferred access.
9008 By default squid will use these IP in order and only rotates to
9009 the next listed when the most preffered fails.
9011 Some load balancing servers based on round robin DNS have been
9012 found not to preserve user session state across requests
9013 to different IP addresses.
9015 Enabling this directive Squid rotates IP's per request.
9018 NAME: pipeline_prefetch
9019 TYPE: pipelinePrefetch
9020 LOC: Config.pipeline_max_prefetch
9022 DEFAULT_DOC: Do not pre-parse pipelined requests.
9024 HTTP clients may send a pipeline of 1+N requests to Squid using a
9025 single connection, without waiting for Squid to respond to the first
9026 of those requests. This option limits the number of concurrent
9027 requests Squid will try to handle in parallel. If set to N, Squid
9028 will try to receive and process up to 1+N requests on the same
9029 connection concurrently.
9031 Defaults to 0 (off) for bandwidth management and access logging
9034 NOTE: pipelining requires persistent connections to clients.
9036 WARNING: pipelining breaks NTLM and Negotiate/Kerberos authentication.
9039 NAME: high_response_time_warning
9042 LOC: Config.warnings.high_rptm
9044 DEFAULT_DOC: disabled.
9046 If the one-minute median response time exceeds this value,
9047 Squid prints a WARNING with debug level 0 to get the
9048 administrators attention. The value is in milliseconds.
9051 NAME: high_page_fault_warning
9053 LOC: Config.warnings.high_pf
9055 DEFAULT_DOC: disabled.
9057 If the one-minute average page fault rate exceeds this
9058 value, Squid prints a WARNING with debug level 0 to get
9059 the administrators attention. The value is in page faults
9063 NAME: high_memory_warning
9065 LOC: Config.warnings.high_memory
9066 IFDEF: HAVE_MSTATS&&HAVE_GNUMALLOC_H
9068 DEFAULT_DOC: disabled.
9070 If the memory usage (as determined by gnumalloc, if available and used)
9071 exceeds this amount, Squid prints a WARNING with debug level 0 to get
9072 the administrators attention.
9074 # TODO: link high_memory_warning to mempools?
9076 NAME: sleep_after_fork
9077 COMMENT: (microseconds)
9079 LOC: Config.sleep_after_fork
9082 When this is set to a non-zero value, the main Squid process
9083 sleeps the specified number of microseconds after a fork()
9084 system call. This sleep may help the situation where your
9085 system reports fork() failures due to lack of (virtual)
9086 memory. Note, however, if you have a lot of child
9087 processes, these sleep delays will add up and your
9088 Squid will not service requests for some amount of time
9089 until all the child processes have been started.
9090 On Windows value less then 1000 (1 milliseconds) are
9094 NAME: windows_ipaddrchangemonitor
9095 IFDEF: _SQUID_WINDOWS_
9099 LOC: Config.onoff.WIN32_IpAddrChangeMonitor
9101 On Windows Squid by default will monitor IP address changes and will
9102 reconfigure itself after any detected event. This is very useful for
9103 proxies connected to internet with dial-up interfaces.
9104 In some cases (a Proxy server acting as VPN gateway is one) it could be
9105 desiderable to disable this behaviour setting this to 'off'.
9106 Note: after changing this, Squid service must be restarted.
9111 IFDEF: USE_SQUID_EUI
9113 LOC: Eui::TheConfig.euiLookup
9115 Whether to lookup the EUI or MAC address of a connected client.
9118 NAME: max_filedescriptors max_filedesc
9121 DEFAULT_DOC: Use operating system limits set by ulimit.
9122 LOC: Config.max_filedescriptors
9124 Reduce the maximum number of filedescriptors supported below
9125 the usual operating system defaults.
9127 Remove from squid.conf to inherit the current ulimit setting.
9129 Note: Changing this requires a restart of Squid. Also
9130 not all I/O types supports large values (eg on Windows).
9137 DEFAULT_DOC: SMP support disabled.
9139 Number of main Squid processes or "workers" to fork and maintain.
9140 0: "no daemon" mode, like running "squid -N ..."
9141 1: "no SMP" mode, start one main Squid process daemon (default)
9142 N: start N main Squid process daemons (i.e., SMP mode)
9144 In SMP mode, each worker does nearly all what a single Squid daemon
9145 does (e.g., listen on http_port and forward HTTP requests).
9148 NAME: cpu_affinity_map
9149 TYPE: CpuAffinityMap
9150 LOC: Config.cpuAffinityMap
9152 DEFAULT_DOC: Let operating system decide.
9154 Usage: cpu_affinity_map process_numbers=P1,P2,... cores=C1,C2,...
9156 Sets 1:1 mapping between Squid processes and CPU cores. For example,
9158 cpu_affinity_map process_numbers=1,2,3,4 cores=1,3,5,7
9160 affects processes 1 through 4 only and places them on the first
9161 four even cores, starting with core #1.
9163 CPU cores are numbered starting from 1. Requires support for
9164 sched_getaffinity(2) and sched_setaffinity(2) system calls.
9166 Multiple cpu_affinity_map options are merged.
projects / thirdparty / squid.git / blob