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 line ("username password" by default) and replies
364 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 Become a TCP tunnel without decoding the connection.
2463 Works with both CONNECT requests and intercepted SSL
2464 connections. This is the default behavior when no
2465 ssl_bump option is given or no ssl_bump ACLs match.
2467 By default, no connections are bumped.
2469 The first matching ssl_bump option wins. If no ACLs match, the
2470 connection is not bumped. Unlike most allow/deny ACL lists, ssl_bump
2471 does not have an implicit "negate the last given option" rule. You
2472 must make that rule explicit if you convert old ssl_bump allow/deny
2473 rules that rely on such an implicit rule.
2475 This clause supports both fast and slow acl types.
2476 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2478 See also: http_port ssl-bump, https_port ssl-bump
2481 # Example: Bump all requests except those originating from
2482 # localhost or those going to example.com.
2484 acl broken_sites dstdomain .example.com
2485 ssl_bump none localhost
2486 ssl_bump none broken_sites
2487 ssl_bump server-first all
2490 NAME: sslproxy_flags
2493 LOC: Config.ssl_client.flags
2496 Various flags modifying the use of SSL while proxying https:// URLs:
2497 DONT_VERIFY_PEER Accept certificates that fail verification.
2498 For refined control, see sslproxy_cert_error.
2499 NO_DEFAULT_CA Don't use the default CA list built in
2503 NAME: sslproxy_cert_error
2506 DEFAULT_DOC: Server certificate errors terminate the transaction.
2507 LOC: Config.ssl_client.cert_error
2510 Use this ACL to bypass server certificate validation errors.
2512 For example, the following lines will bypass all validation errors
2513 when talking to servers for example.com. All other
2514 validation errors will result in ERR_SECURE_CONNECT_FAIL error.
2516 acl BrokenButTrustedServers dstdomain example.com
2517 sslproxy_cert_error allow BrokenButTrustedServers
2518 sslproxy_cert_error deny all
2520 This clause only supports fast acl types.
2521 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2522 Using slow acl types may result in server crashes
2524 Without this option, all server certificate validation errors
2525 terminate the transaction to protect Squid and the client.
2527 SQUID_X509_V_ERR_INFINITE_VALIDATION error cannot be bypassed
2528 but should not happen unless your OpenSSL library is buggy.
2531 Bypassing validation errors is dangerous because an
2532 error usually implies that the server cannot be trusted
2533 and the connection may be insecure.
2535 See also: sslproxy_flags and DONT_VERIFY_PEER.
2538 NAME: sslproxy_cert_sign
2541 POSTSCRIPTUM: signUntrusted ssl::certUntrusted
2542 POSTSCRIPTUM: signSelf ssl::certSelfSigned
2543 POSTSCRIPTUM: signTrusted all
2544 TYPE: sslproxy_cert_sign
2545 LOC: Config.ssl_client.cert_sign
2548 sslproxy_cert_sign <signing algorithm> acl ...
2550 The following certificate signing algorithms are supported:
2553 Sign using the configured CA certificate which is usually
2554 placed in and trusted by end-user browsers. This is the
2555 default for trusted origin server certificates.
2558 Sign to guarantee an X509_V_ERR_CERT_UNTRUSTED browser error.
2559 This is the default for untrusted origin server certificates
2560 that are not self-signed (see ssl::certUntrusted).
2563 Sign using a self-signed certificate with the right CN to
2564 generate a X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT error in the
2565 browser. This is the default for self-signed origin server
2566 certificates (see ssl::certSelfSigned).
2568 This clause only supports fast acl types.
2570 When sslproxy_cert_sign acl(s) match, Squid uses the corresponding
2571 signing algorithm to generate the certificate and ignores all
2572 subsequent sslproxy_cert_sign options (the first match wins). If no
2573 acl(s) match, the default signing algorithm is determined by errors
2574 detected when obtaining and validating the origin server certificate.
2576 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2577 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2578 CONNECT request that carries a domain name. In all other cases (CONNECT
2579 to an IP address or an intercepted SSL connection), Squid cannot detect
2580 the domain mismatch at certificate generation time when
2581 bump-server-first is used.
2584 NAME: sslproxy_cert_adapt
2587 TYPE: sslproxy_cert_adapt
2588 LOC: Config.ssl_client.cert_adapt
2591 sslproxy_cert_adapt <adaptation algorithm> acl ...
2593 The following certificate adaptation algorithms are supported:
2596 Sets the "Not After" property to the "Not After" property of
2597 the CA certificate used to sign generated certificates.
2600 Sets the "Not Before" property to the "Not Before" property of
2601 the CA certificate used to sign generated certificates.
2603 setCommonName or setCommonName{CN}
2604 Sets Subject.CN property to the host name specified as a
2605 CN parameter or, if no explicit CN parameter was specified,
2606 extracted from the CONNECT request. It is a misconfiguration
2607 to use setCommonName without an explicit parameter for
2608 intercepted or tproxied SSL connections.
2610 This clause only supports fast acl types.
2612 Squid first groups sslproxy_cert_adapt options by adaptation algorithm.
2613 Within a group, when sslproxy_cert_adapt acl(s) match, Squid uses the
2614 corresponding adaptation algorithm to generate the certificate and
2615 ignores all subsequent sslproxy_cert_adapt options in that algorithm's
2616 group (i.e., the first match wins within each algorithm group). If no
2617 acl(s) match, the default mimicking action takes place.
2619 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2620 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2621 CONNECT request that carries a domain name. In all other cases (CONNECT
2622 to an IP address or an intercepted SSL connection), Squid cannot detect
2623 the domain mismatch at certificate generation time when
2624 bump-server-first is used.
2627 NAME: sslpassword_program
2630 LOC: Config.Program.ssl_password
2633 Specify a program used for entering SSL key passphrases
2634 when using encrypted SSL certificate keys. If not specified
2635 keys must either be unencrypted, or Squid started with the -N
2636 option to allow it to query interactively for the passphrase.
2638 The key file name is given as argument to the program allowing
2639 selection of the right password if you have multiple encrypted
2644 OPTIONS RELATING TO EXTERNAL SSL_CRTD
2645 -----------------------------------------------------------------------------
2648 NAME: sslcrtd_program
2651 DEFAULT: @DEFAULT_SSL_CRTD@ -s @DEFAULT_SSL_DB_DIR@ -M 4MB
2652 LOC: Ssl::TheConfig.ssl_crtd
2654 Specify the location and options of the executable for ssl_crtd process.
2655 @DEFAULT_SSL_CRTD@ program requires -s and -M parameters
2656 For more information use:
2657 @DEFAULT_SSL_CRTD@ -h
2660 NAME: sslcrtd_children
2661 TYPE: HelperChildConfig
2663 DEFAULT: 32 startup=5 idle=1
2664 LOC: Ssl::TheConfig.ssl_crtdChildren
2666 The maximum number of processes spawn to service ssl server.
2667 The maximum this may be safely set to is 32.
2669 The startup= and idle= options allow some measure of skew in your
2674 Sets the minimum number of processes to spawn when Squid
2675 starts or reconfigures. When set to zero the first request will
2676 cause spawning of the first child process to handle it.
2678 Starting too few children temporary slows Squid under load while it
2679 tries to spawn enough additional processes to cope with traffic.
2683 Sets a minimum of how many processes Squid is to try and keep available
2684 at all times. When traffic begins to rise above what the existing
2685 processes can handle this many more will be spawned up to the maximum
2686 configured. A minimum setting of 1 is required.
2688 You must have at least one ssl_crtd process.
2691 NAME: sslcrtvalidator_program
2695 LOC: Ssl::TheConfig.ssl_crt_validator
2697 Specify the location and options of the executable for ssl_crt_validator
2700 Usage: sslcrtvalidator_program [ttl=n] [cache=n] path ...
2703 ttl=n TTL in seconds for cached results. The default is 60 secs
2704 cache=n limit the result cache size. The default value is 2048
2707 NAME: sslcrtvalidator_children
2708 TYPE: HelperChildConfig
2710 DEFAULT: 32 startup=5 idle=1 concurrency=1
2711 LOC: Ssl::TheConfig.ssl_crt_validator_Children
2713 The maximum number of processes spawn to service SSL server.
2714 The maximum this may be safely set to is 32.
2716 The startup= and idle= options allow some measure of skew in your
2721 Sets the minimum number of processes to spawn when Squid
2722 starts or reconfigures. When set to zero the first request will
2723 cause spawning of the first child process to handle it.
2725 Starting too few children temporary slows Squid under load while it
2726 tries to spawn enough additional processes to cope with traffic.
2730 Sets a minimum of how many processes Squid is to try and keep available
2731 at all times. When traffic begins to rise above what the existing
2732 processes can handle this many more will be spawned up to the maximum
2733 configured. A minimum setting of 1 is required.
2737 The number of requests each certificate validator helper can handle in
2738 parallel. A value of 0 indicates the certficate validator does not
2739 support concurrency. Defaults to 1.
2741 When this directive is set to a value >= 1 then the protocol
2742 used to communicate with the helper is modified to include
2743 a request ID in front of the request/response. The request
2744 ID from the request must be echoed back with the response
2747 You must have at least one ssl_crt_validator process.
2751 OPTIONS WHICH AFFECT THE NEIGHBOR SELECTION ALGORITHM
2752 -----------------------------------------------------------------------------
2760 To specify other caches in a hierarchy, use the format:
2762 cache_peer hostname type http-port icp-port [options]
2767 # hostname type port port options
2768 # -------------------- -------- ----- ----- -----------
2769 cache_peer parent.foo.net parent 3128 3130 default
2770 cache_peer sib1.foo.net sibling 3128 3130 proxy-only
2771 cache_peer sib2.foo.net sibling 3128 3130 proxy-only
2772 cache_peer example.com parent 80 0 default
2773 cache_peer cdn.example.com sibling 3128 0
2775 type: either 'parent', 'sibling', or 'multicast'.
2777 proxy-port: The port number where the peer accept HTTP requests.
2778 For other Squid proxies this is usually 3128
2779 For web servers this is usually 80
2781 icp-port: Used for querying neighbor caches about objects.
2782 Set to 0 if the peer does not support ICP or HTCP.
2783 See ICP and HTCP options below for additional details.
2786 ==== ICP OPTIONS ====
2788 You MUST also set icp_port and icp_access explicitly when using these options.
2789 The defaults will prevent peer traffic using ICP.
2792 no-query Disable ICP queries to this neighbor.
2795 Indicates the named peer is a member of a multicast group.
2796 ICP queries will not be sent directly to the peer, but ICP
2797 replies will be accepted from it.
2799 closest-only Indicates that, for ICP_OP_MISS replies, we'll only forward
2800 CLOSEST_PARENT_MISSes and never FIRST_PARENT_MISSes.
2803 To only send ICP queries to this neighbor infrequently.
2804 This is used to keep the neighbor round trip time updated
2805 and is usually used in conjunction with weighted-round-robin.
2808 ==== HTCP OPTIONS ====
2810 You MUST also set htcp_port and htcp_access explicitly when using these options.
2811 The defaults will prevent peer traffic using HTCP.
2814 htcp Send HTCP, instead of ICP, queries to the neighbor.
2815 You probably also want to set the "icp-port" to 4827
2816 instead of 3130. This directive accepts a comma separated
2817 list of options described below.
2819 htcp=oldsquid Send HTCP to old Squid versions (2.5 or earlier).
2821 htcp=no-clr Send HTCP to the neighbor but without
2822 sending any CLR requests. This cannot be used with
2825 htcp=only-clr Send HTCP to the neighbor but ONLY CLR requests.
2826 This cannot be used with no-clr.
2829 Send HTCP to the neighbor including CLRs but only when
2830 they do not result from PURGE requests.
2833 Forward any HTCP CLR requests this proxy receives to the peer.
2836 ==== PEER SELECTION METHODS ====
2838 The default peer selection method is ICP, with the first responding peer
2839 being used as source. These options can be used for better load balancing.
2842 default This is a parent cache which can be used as a "last-resort"
2843 if a peer cannot be located by any of the peer-selection methods.
2844 If specified more than once, only the first is used.
2846 round-robin Load-Balance parents which should be used in a round-robin
2847 fashion in the absence of any ICP queries.
2848 weight=N can be used to add bias.
2850 weighted-round-robin
2851 Load-Balance parents which should be used in a round-robin
2852 fashion with the frequency of each parent being based on the
2853 round trip time. Closer parents are used more often.
2854 Usually used for background-ping parents.
2855 weight=N can be used to add bias.
2857 carp Load-Balance parents which should be used as a CARP array.
2858 The requests will be distributed among the parents based on the
2859 CARP load balancing hash function based on their weight.
2861 userhash Load-balance parents based on the client proxy_auth or ident username.
2863 sourcehash Load-balance parents based on the client source IP.
2866 To be used only for cache peers of type "multicast".
2867 ALL members of this multicast group have "sibling"
2868 relationship with it, not "parent". This is to a multicast
2869 group when the requested object would be fetched only from
2870 a "parent" cache, anyway. It's useful, e.g., when
2871 configuring a pool of redundant Squid proxies, being
2872 members of the same multicast group.
2875 ==== PEER SELECTION OPTIONS ====
2877 weight=N use to affect the selection of a peer during any weighted
2878 peer-selection mechanisms.
2879 The weight must be an integer; default is 1,
2880 larger weights are favored more.
2881 This option does not affect parent selection if a peering
2882 protocol is not in use.
2884 basetime=N Specify a base amount to be subtracted from round trip
2886 It is subtracted before division by weight in calculating
2887 which parent to fectch from. If the rtt is less than the
2888 base time the rtt is set to a minimal value.
2890 ttl=N Specify a TTL to use when sending multicast ICP queries
2892 Only useful when sending to a multicast group.
2893 Because we don't accept ICP replies from random
2894 hosts, you must configure other group members as
2895 peers with the 'multicast-responder' option.
2897 no-delay To prevent access to this neighbor from influencing the
2900 digest-url=URL Tell Squid to fetch the cache digest (if digests are
2901 enabled) for this host from the specified URL rather
2902 than the Squid default location.
2905 ==== CARP OPTIONS ====
2907 carp-key=key-specification
2908 use a different key than the full URL to hash against the peer.
2909 the key-specification is a comma-separated list of the keywords
2910 scheme, host, port, path, params
2911 Order is not important.
2913 ==== ACCELERATOR / REVERSE-PROXY OPTIONS ====
2915 originserver Causes this parent to be contacted as an origin server.
2916 Meant to be used in accelerator setups when the peer
2920 Set the Host header of requests forwarded to this peer.
2921 Useful in accelerator setups where the server (peer)
2922 expects a certain domain name but clients may request
2923 others. ie example.com or www.example.com
2925 no-digest Disable request of cache digests.
2928 Disables requesting ICMP RTT database (NetDB).
2931 ==== AUTHENTICATION OPTIONS ====
2934 If this is a personal/workgroup proxy and your parent
2935 requires proxy authentication.
2937 Note: The string can include URL escapes (i.e. %20 for
2938 spaces). This also means % must be written as %%.
2941 Send login details received from client to this peer.
2942 Both Proxy- and WWW-Authorization headers are passed
2943 without alteration to the peer.
2944 Authentication is not required by Squid for this to work.
2946 Note: This will pass any form of authentication but
2947 only Basic auth will work through a proxy unless the
2948 connection-auth options are also used.
2950 login=PASS Send login details received from client to this peer.
2951 Authentication is not required by this option.
2953 If there are no client-provided authentication headers
2954 to pass on, but username and password are available
2955 from an external ACL user= and password= result tags
2956 they may be sent instead.
2958 Note: To combine this with proxy_auth both proxies must
2959 share the same user database as HTTP only allows for
2960 a single login (one for proxy, one for origin server).
2961 Also be warned this will expose your users proxy
2962 password to the peer. USE WITH CAUTION
2965 Send the username to the upstream cache, but with a
2966 fixed password. This is meant to be used when the peer
2967 is in another administrative domain, but it is still
2968 needed to identify each user.
2969 The star can optionally be followed by some extra
2970 information which is added to the username. This can
2971 be used to identify this proxy to the peer, similar to
2972 the login=username:password option above.
2975 If this is a personal/workgroup proxy and your parent
2976 requires a secure proxy authentication.
2977 The first principal from the default keytab or defined by
2978 the environment variable KRB5_KTNAME will be used.
2980 WARNING: The connection may transmit requests from multiple
2981 clients. Negotiate often assumes end-to-end authentication
2982 and a single-client. Which is not strictly true here.
2984 login=NEGOTIATE:principal_name
2985 If this is a personal/workgroup proxy and your parent
2986 requires a secure proxy authentication.
2987 The principal principal_name from the default keytab or
2988 defined by the environment variable KRB5_KTNAME will be
2991 WARNING: The connection may transmit requests from multiple
2992 clients. Negotiate often assumes end-to-end authentication
2993 and a single-client. Which is not strictly true here.
2995 connection-auth=on|off
2996 Tell Squid that this peer does or not support Microsoft
2997 connection oriented authentication, and any such
2998 challenges received from there should be ignored.
2999 Default is auto to automatically determine the status
3003 ==== SSL / HTTPS / TLS OPTIONS ====
3005 ssl Encrypt connections to this peer with SSL/TLS.
3007 sslcert=/path/to/ssl/certificate
3008 A client SSL certificate to use when connecting to
3011 sslkey=/path/to/ssl/key
3012 The private SSL key corresponding to sslcert above.
3013 If 'sslkey' is not specified 'sslcert' is assumed to
3014 reference a combined file containing both the
3015 certificate and the key.
3017 sslversion=1|2|3|4|5|6
3018 The SSL version to use when connecting to this peer
3019 1 = automatic (default)
3026 sslcipher=... The list of valid SSL ciphers to use when connecting
3029 ssloptions=... Specify various SSL implementation options:
3031 NO_SSLv2 Disallow the use of SSLv2
3032 NO_SSLv3 Disallow the use of SSLv3
3033 NO_TLSv1 Disallow the use of TLSv1.0
3034 NO_TLSv1_1 Disallow the use of TLSv1.1
3035 NO_TLSv1_2 Disallow the use of TLSv1.2
3037 Always create a new key when using
3038 temporary/ephemeral DH key exchanges
3039 ALL Enable various bug workarounds
3040 suggested as "harmless" by OpenSSL
3041 Be warned that this reduces SSL/TLS
3042 strength to some attacks.
3044 See the OpenSSL SSL_CTX_set_options documentation for a
3047 sslcafile=... A file containing additional CA certificates to use
3048 when verifying the peer certificate.
3050 sslcapath=... A directory containing additional CA certificates to
3051 use when verifying the peer certificate.
3053 sslcrlfile=... A certificate revocation list file to use when
3054 verifying the peer certificate.
3056 sslflags=... Specify various flags modifying the SSL implementation:
3059 Accept certificates even if they fail to
3062 Don't use the default CA list built in
3065 Don't verify the peer certificate
3066 matches the server name
3068 ssldomain= The peer name as advertised in it's certificate.
3069 Used for verifying the correctness of the received peer
3070 certificate. If not specified the peer hostname will be
3074 Enable the "Front-End-Https: On" header needed when
3075 using Squid as a SSL frontend in front of Microsoft OWA.
3076 See MS KB document Q307347 for details on this header.
3077 If set to auto the header will only be added if the
3078 request is forwarded as a https:// URL.
3081 ==== GENERAL OPTIONS ====
3084 A peer-specific connect timeout.
3085 Also see the peer_connect_timeout directive.
3087 connect-fail-limit=N
3088 How many times connecting to a peer must fail before
3089 it is marked as down. Standby connection failures
3090 count towards this limit. Default is 10.
3092 allow-miss Disable Squid's use of only-if-cached when forwarding
3093 requests to siblings. This is primarily useful when
3094 icp_hit_stale is used by the sibling. To extensive use
3095 of this option may result in forwarding loops, and you
3096 should avoid having two-way peerings with this option.
3097 For example to deny peer usage on requests from peer
3098 by denying cache_peer_access if the source is a peer.
3100 max-conn=N Limit the number of concurrent connections the Squid
3101 may open to this peer, including already opened idle
3102 and standby connections. There is no peer-specific
3103 connection limit by default.
3105 A peer exceeding the limit is not used for new
3106 requests unless a standby connection is available.
3108 max-conn currently works poorly with idle persistent
3109 connections: When a peer reaches its max-conn limit,
3110 and there are idle persistent connections to the peer,
3111 the peer may not be selected because the limiting code
3112 does not know whether Squid can reuse those idle
3115 standby=N Maintain a pool of N "hot standby" connections to an
3116 UP peer, available for requests when no idle
3117 persistent connection is available (or safe) to use.
3118 By default and with zero N, no such pool is maintained.
3119 N must not exceed the max-conn limit (if any).
3121 At start or after reconfiguration, Squid opens new TCP
3122 standby connections until there are N connections
3123 available and then replenishes the standby pool as
3124 opened connections are used up for requests. A used
3125 connection never goes back to the standby pool, but
3126 may go to the regular idle persistent connection pool
3127 shared by all peers and origin servers.
3129 Squid never opens multiple new standby connections
3130 concurrently. This one-at-a-time approach minimizes
3131 flooding-like effect on peers. Furthermore, just a few
3132 standby connections should be sufficient in most cases
3133 to supply most new requests with a ready-to-use
3136 Standby connections obey server_idle_pconn_timeout.
3137 For the feature to work as intended, the peer must be
3138 configured to accept and keep them open longer than
3139 the idle timeout at the connecting Squid, to minimize
3140 race conditions typical to idle used persistent
3141 connections. Default request_timeout and
3142 server_idle_pconn_timeout values ensure such a
3145 name=xxx Unique name for the peer.
3146 Required if you have multiple peers on the same host
3147 but different ports.
3148 This name can be used in cache_peer_access and similar
3149 directives to dentify the peer.
3150 Can be used by outgoing access controls through the
3153 no-tproxy Do not use the client-spoof TPROXY support when forwarding
3154 requests to this peer. Use normal address selection instead.
3155 This overrides the spoof_client_ip ACL.
3157 proxy-only objects fetched from the peer will not be stored locally.
3161 NAME: cache_peer_domain cache_host_domain
3166 Use to limit the domains for which a neighbor cache will be
3170 cache_peer_domain cache-host domain [domain ...]
3171 cache_peer_domain cache-host !domain
3173 For example, specifying
3175 cache_peer_domain parent.foo.net .edu
3177 has the effect such that UDP query packets are sent to
3178 'bigserver' only when the requested object exists on a
3179 server in the .edu domain. Prefixing the domainname
3180 with '!' means the cache will be queried for objects
3183 NOTE: * Any number of domains may be given for a cache-host,
3184 either on the same or separate lines.
3185 * When multiple domains are given for a particular
3186 cache-host, the first matched domain is applied.
3187 * Cache hosts with no domain restrictions are queried
3189 * There are no defaults.
3190 * There is also a 'cache_peer_access' tag in the ACL
3194 NAME: cache_peer_access
3199 Similar to 'cache_peer_domain' but provides more flexibility by
3203 cache_peer_access cache-host allow|deny [!]aclname ...
3205 The syntax is identical to 'http_access' and the other lists of
3206 ACL elements. See the comments for 'http_access' below, or
3207 the Squid FAQ (http://wiki.squid-cache.org/SquidFaq/SquidAcl).
3210 NAME: neighbor_type_domain
3211 TYPE: hostdomaintype
3213 DEFAULT_DOC: The peer type from cache_peer directive is used for all requests to that peer.
3216 Modify the cache_peer neighbor type when passing requests
3217 about specific domains to the peer.
3220 neighbor_type_domain neighbor parent|sibling domain domain ...
3223 cache_peer foo.example.com parent 3128 3130
3224 neighbor_type_domain foo.example.com sibling .au .de
3226 The above configuration treats all requests to foo.example.com as a
3227 parent proxy unless the request is for a .au or .de ccTLD domain name.
3230 NAME: dead_peer_timeout
3234 LOC: Config.Timeout.deadPeer
3236 This controls how long Squid waits to declare a peer cache
3237 as "dead." If there are no ICP replies received in this
3238 amount of time, Squid will declare the peer dead and not
3239 expect to receive any further ICP replies. However, it
3240 continues to send ICP queries, and will mark the peer as
3241 alive upon receipt of the first subsequent ICP reply.
3243 This timeout also affects when Squid expects to receive ICP
3244 replies from peers. If more than 'dead_peer' seconds have
3245 passed since the last ICP reply was received, Squid will not
3246 expect to receive an ICP reply on the next query. Thus, if
3247 your time between requests is greater than this timeout, you
3248 will see a lot of requests sent DIRECT to origin servers
3249 instead of to your parents.
3252 NAME: forward_max_tries
3255 LOC: Config.forward_max_tries
3257 Controls how many different forward paths Squid will try
3258 before giving up. See also forward_timeout.
3260 NOTE: connect_retries (default: none) can make each of these
3261 possible forwarding paths be tried multiple times.
3264 NAME: hierarchy_stoplist
3267 LOC: Config.hierarchy_stoplist
3269 A list of words which, if found in a URL, cause the object to
3270 be handled directly by this cache. In other words, use this
3271 to not query neighbor caches for certain objects. You may
3272 list this option multiple times.
3275 hierarchy_stoplist cgi-bin ?
3277 Note: never_direct overrides this option.
3281 MEMORY CACHE OPTIONS
3282 -----------------------------------------------------------------------------
3289 LOC: Config.memMaxSize
3291 NOTE: THIS PARAMETER DOES NOT SPECIFY THE MAXIMUM PROCESS SIZE.
3292 IT ONLY PLACES A LIMIT ON HOW MUCH ADDITIONAL MEMORY SQUID WILL
3293 USE AS A MEMORY CACHE OF OBJECTS. SQUID USES MEMORY FOR OTHER
3294 THINGS AS WELL. SEE THE SQUID FAQ SECTION 8 FOR DETAILS.
3296 'cache_mem' specifies the ideal amount of memory to be used
3298 * In-Transit objects
3300 * Negative-Cached objects
3302 Data for these objects are stored in 4 KB blocks. This
3303 parameter specifies the ideal upper limit on the total size of
3304 4 KB blocks allocated. In-Transit objects take the highest
3307 In-transit objects have priority over the others. When
3308 additional space is needed for incoming data, negative-cached
3309 and hot objects will be released. In other words, the
3310 negative-cached and hot objects will fill up any unused space
3311 not needed for in-transit objects.
3313 If circumstances require, this limit will be exceeded.
3314 Specifically, if your incoming request rate requires more than
3315 'cache_mem' of memory to hold in-transit objects, Squid will
3316 exceed this limit to satisfy the new requests. When the load
3317 decreases, blocks will be freed until the high-water mark is
3318 reached. Thereafter, blocks will be used to store hot
3321 If shared memory caching is enabled, Squid does not use the shared
3322 cache space for in-transit objects, but they still consume as much
3323 local memory as they need. For more details about the shared memory
3324 cache, see memory_cache_shared.
3327 NAME: maximum_object_size_in_memory
3331 LOC: Config.Store.maxInMemObjSize
3333 Objects greater than this size will not be attempted to kept in
3334 the memory cache. This should be set high enough to keep objects
3335 accessed frequently in memory to improve performance whilst low
3336 enough to keep larger objects from hoarding cache_mem.
3339 NAME: memory_cache_shared
3342 LOC: Config.memShared
3344 DEFAULT_DOC: "on" where supported if doing memory caching with multiple SMP workers.
3346 Controls whether the memory cache is shared among SMP workers.
3348 The shared memory cache is meant to occupy cache_mem bytes and replace
3349 the non-shared memory cache, although some entities may still be
3350 cached locally by workers for now (e.g., internal and in-transit
3351 objects may be served from a local memory cache even if shared memory
3352 caching is enabled).
3354 By default, the memory cache is shared if and only if all of the
3355 following conditions are satisfied: Squid runs in SMP mode with
3356 multiple workers, cache_mem is positive, and Squid environment
3357 supports required IPC primitives (e.g., POSIX shared memory segments
3358 and GCC-style atomic operations).
3360 To avoid blocking locks, shared memory uses opportunistic algorithms
3361 that do not guarantee that every cachable entity that could have been
3362 shared among SMP workers will actually be shared.
3364 Currently, entities exceeding 32KB in size cannot be shared.
3367 NAME: memory_cache_mode
3371 DEFAULT_DOC: Keep the most recently fetched objects in memory
3373 Controls which objects to keep in the memory cache (cache_mem)
3375 always Keep most recently fetched objects in memory (default)
3377 disk Only disk cache hits are kept in memory, which means
3378 an object must first be cached on disk and then hit
3379 a second time before cached in memory.
3381 network Only objects fetched from network is kept in memory
3384 NAME: memory_replacement_policy
3386 LOC: Config.memPolicy
3389 The memory replacement policy parameter determines which
3390 objects are purged from memory when memory space is needed.
3392 See cache_replacement_policy for details on algorithms.
3397 -----------------------------------------------------------------------------
3400 NAME: cache_replacement_policy
3402 LOC: Config.replPolicy
3405 The cache replacement policy parameter determines which
3406 objects are evicted (replaced) when disk space is needed.
3408 lru : Squid's original list based LRU policy
3409 heap GDSF : Greedy-Dual Size Frequency
3410 heap LFUDA: Least Frequently Used with Dynamic Aging
3411 heap LRU : LRU policy implemented using a heap
3413 Applies to any cache_dir lines listed below this directive.
3415 The LRU policies keeps recently referenced objects.
3417 The heap GDSF policy optimizes object hit rate by keeping smaller
3418 popular objects in cache so it has a better chance of getting a
3419 hit. It achieves a lower byte hit rate than LFUDA though since
3420 it evicts larger (possibly popular) objects.
3422 The heap LFUDA policy keeps popular objects in cache regardless of
3423 their size and thus optimizes byte hit rate at the expense of
3424 hit rate since one large, popular object will prevent many
3425 smaller, slightly less popular objects from being cached.
3427 Both policies utilize a dynamic aging mechanism that prevents
3428 cache pollution that can otherwise occur with frequency-based
3429 replacement policies.
3431 NOTE: if using the LFUDA replacement policy you should increase
3432 the value of maximum_object_size above its default of 4 MB to
3433 to maximize the potential byte hit rate improvement of LFUDA.
3435 For more information about the GDSF and LFUDA cache replacement
3436 policies see http://www.hpl.hp.com/techreports/1999/HPL-1999-69.html
3437 and http://fog.hpl.external.hp.com/techreports/98/HPL-98-173.html.
3440 NAME: minimum_object_size
3444 DEFAULT_DOC: no limit
3445 LOC: Config.Store.minObjectSize
3447 Objects smaller than this size will NOT be saved on disk. The
3448 value is specified in bytes, and the default is 0 KB, which
3449 means all responses can be stored.
3452 NAME: maximum_object_size
3456 LOC: Config.Store.maxObjectSize
3458 Set the default value for max-size parameter on any cache_dir.
3459 The value is specified in bytes, and the default is 4 MB.
3461 If you wish to get a high BYTES hit ratio, you should probably
3462 increase this (one 32 MB object hit counts for 3200 10KB
3465 If you wish to increase hit ratio more than you want to
3466 save bandwidth you should leave this low.
3468 NOTE: if using the LFUDA replacement policy you should increase
3469 this value to maximize the byte hit rate improvement of LFUDA!
3470 See cache_replacement_policy for a discussion of this policy.
3476 DEFAULT_DOC: No disk cache. Store cache ojects only in memory.
3477 LOC: Config.cacheSwap
3480 cache_dir Type Directory-Name Fs-specific-data [options]
3482 You can specify multiple cache_dir lines to spread the
3483 cache among different disk partitions.
3485 Type specifies the kind of storage system to use. Only "ufs"
3486 is built by default. To enable any of the other storage systems
3487 see the --enable-storeio configure option.
3489 'Directory' is a top-level directory where cache swap
3490 files will be stored. If you want to use an entire disk
3491 for caching, this can be the mount-point directory.
3492 The directory must exist and be writable by the Squid
3493 process. Squid will NOT create this directory for you.
3495 In SMP configurations, cache_dir must not precede the workers option
3496 and should use configuration macros or conditionals to give each
3497 worker interested in disk caching a dedicated cache directory.
3500 ==== The ufs store type ====
3502 "ufs" is the old well-known Squid storage format that has always
3506 cache_dir ufs Directory-Name Mbytes L1 L2 [options]
3508 'Mbytes' is the amount of disk space (MB) to use under this
3509 directory. The default is 100 MB. Change this to suit your
3510 configuration. Do NOT put the size of your disk drive here.
3511 Instead, if you want Squid to use the entire disk drive,
3512 subtract 20% and use that value.
3514 'L1' is the number of first-level subdirectories which
3515 will be created under the 'Directory'. The default is 16.
3517 'L2' is the number of second-level subdirectories which
3518 will be created under each first-level directory. The default
3522 ==== The aufs store type ====
3524 "aufs" uses the same storage format as "ufs", utilizing
3525 POSIX-threads to avoid blocking the main Squid process on
3526 disk-I/O. This was formerly known in Squid as async-io.
3529 cache_dir aufs Directory-Name Mbytes L1 L2 [options]
3531 see argument descriptions under ufs above
3534 ==== The diskd store type ====
3536 "diskd" uses the same storage format as "ufs", utilizing a
3537 separate process to avoid blocking the main Squid process on
3541 cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n]
3543 see argument descriptions under ufs above
3545 Q1 specifies the number of unacknowledged I/O requests when Squid
3546 stops opening new files. If this many messages are in the queues,
3547 Squid won't open new files. Default is 64
3549 Q2 specifies the number of unacknowledged messages when Squid
3550 starts blocking. If this many messages are in the queues,
3551 Squid blocks until it receives some replies. Default is 72
3553 When Q1 < Q2 (the default), the cache directory is optimized
3554 for lower response time at the expense of a decrease in hit
3555 ratio. If Q1 > Q2, the cache directory is optimized for
3556 higher hit ratio at the expense of an increase in response
3560 ==== The rock store type ====
3563 cache_dir rock Directory-Name Mbytes [options]
3565 The Rock Store type is a database-style storage. All cached
3566 entries are stored in a "database" file, using fixed-size slots.
3567 A single entry occupies one or more slots.
3569 If possible, Squid using Rock Store creates a dedicated kid
3570 process called "disker" to avoid blocking Squid worker(s) on disk
3571 I/O. One disker kid is created for each rock cache_dir. Diskers
3572 are created only when Squid, running in daemon mode, has support
3573 for the IpcIo disk I/O module.
3575 swap-timeout=msec: Squid will not start writing a miss to or
3576 reading a hit from disk if it estimates that the swap operation
3577 will take more than the specified number of milliseconds. By
3578 default and when set to zero, disables the disk I/O time limit
3579 enforcement. Ignored when using blocking I/O module because
3580 blocking synchronous I/O does not allow Squid to estimate the
3581 expected swap wait time.
3583 max-swap-rate=swaps/sec: Artificially limits disk access using
3584 the specified I/O rate limit. Swap out requests that
3585 would cause the average I/O rate to exceed the limit are
3586 delayed. Individual swap in requests (i.e., hits or reads) are
3587 not delayed, but they do contribute to measured swap rate and
3588 since they are placed in the same FIFO queue as swap out
3589 requests, they may wait longer if max-swap-rate is smaller.
3590 This is necessary on file systems that buffer "too
3591 many" writes and then start blocking Squid and other processes
3592 while committing those writes to disk. Usually used together
3593 with swap-timeout to avoid excessive delays and queue overflows
3594 when disk demand exceeds available disk "bandwidth". By default
3595 and when set to zero, disables the disk I/O rate limit
3596 enforcement. Currently supported by IpcIo module only.
3598 slot-size=bytes: The size of a database "record" used for
3599 storing cached responses. A cached response occupies at least
3600 one slot and all database I/O is done using individual slots so
3601 increasing this parameter leads to more disk space waste while
3602 decreasing it leads to more disk I/O overheads. Should be a
3603 multiple of your operating system I/O page size. Defaults to
3604 16KBytes. A housekeeping header is stored with each slot and
3605 smaller slot-sizes will be rejected. The header is smaller than
3609 ==== COMMON OPTIONS ====
3611 no-store no new objects should be stored to this cache_dir.
3613 min-size=n the minimum object size in bytes this cache_dir
3614 will accept. It's used to restrict a cache_dir
3615 to only store large objects (e.g. AUFS) while
3616 other stores are optimized for smaller objects
3620 max-size=n the maximum object size in bytes this cache_dir
3622 The value in maximum_object_size directive sets
3623 the default unless more specific details are
3624 available (ie a small store capacity).
3626 Note: To make optimal use of the max-size limits you should order
3627 the cache_dir lines with the smallest max-size value first.
3631 # Uncomment and adjust the following to add a disk cache directory.
3632 #cache_dir ufs @DEFAULT_SWAP_DIR@ 100 16 256
3636 NAME: store_dir_select_algorithm
3638 LOC: Config.store_dir_select_algorithm
3641 How Squid selects which cache_dir to use when the response
3642 object will fit into more than one.
3644 Regardless of which algorithm is used the cache_dir min-size
3645 and max-size parameters are obeyed. As such they can affect
3646 the selection algorithm by limiting the set of considered
3653 This algorithm is suited to caches with similar cache_dir
3654 sizes and disk speeds.
3656 The disk with the least I/O pending is selected.
3657 When there are multiple disks with the same I/O load ranking
3658 the cache_dir with most available capacity is selected.
3660 When a mix of cache_dir sizes are configured the faster disks
3661 have a naturally lower I/O loading and larger disks have more
3662 capacity. So space used to store objects and data throughput
3663 may be very unbalanced towards larger disks.
3668 This algorithm is suited to caches with unequal cache_dir
3671 Each cache_dir is selected in a rotation. The next suitable
3674 Available cache_dir capacity is only considered in relation
3675 to whether the object will fit and meets the min-size and
3676 max-size parameters.
3678 Disk I/O loading is only considered to prevent overload on slow
3679 disks. This algorithm does not spread objects by size, so any
3680 I/O loading per-disk may appear very unbalanced and volatile.
3684 NAME: max_open_disk_fds
3686 LOC: Config.max_open_disk_fds
3688 DEFAULT_DOC: no limit
3690 To avoid having disk as the I/O bottleneck Squid can optionally
3691 bypass the on-disk cache if more than this amount of disk file
3692 descriptors are open.
3694 A value of 0 indicates no limit.
3697 NAME: cache_swap_low
3698 COMMENT: (percent, 0-100)
3701 LOC: Config.Swap.lowWaterMark
3703 The low-water mark for cache object replacement.
3704 Replacement begins when the swap (disk) usage is above the
3705 low-water mark and attempts to maintain utilization near the
3706 low-water mark. As swap utilization gets close to high-water
3707 mark object eviction becomes more aggressive. If utilization is
3708 close to the low-water mark less replacement is done each time.
3710 Defaults are 90% and 95%. If you have a large cache, 5% could be
3711 hundreds of MB. If this is the case you may wish to set these
3712 numbers closer together.
3714 See also cache_swap_high
3717 NAME: cache_swap_high
3718 COMMENT: (percent, 0-100)
3721 LOC: Config.Swap.highWaterMark
3723 The high-water mark for cache object replacement.
3724 Replacement begins when the swap (disk) usage is above the
3725 low-water mark and attempts to maintain utilization near the
3726 low-water mark. As swap utilization gets close to high-water
3727 mark object eviction becomes more aggressive. If utilization is
3728 close to the low-water mark less replacement is done each time.
3730 Defaults are 90% and 95%. If you have a large cache, 5% could be
3731 hundreds of MB. If this is the case you may wish to set these
3732 numbers closer together.
3734 See also cache_swap_low
3739 -----------------------------------------------------------------------------
3746 DEFAULT_DOC: The format definitions squid, common, combined, referrer, useragent are built in.
3750 logformat <name> <format specification>
3752 Defines an access log format.
3754 The <format specification> is a string with embedded % format codes
3756 % format codes all follow the same basic structure where all but
3757 the formatcode is optional. Output strings are automatically escaped
3758 as required according to their context and the output format
3759 modifiers are usually not needed, but can be specified if an explicit
3760 output format is desired.
3762 % ["|[|'|#] [-] [[0]width] [{argument}] formatcode
3764 " output in quoted string format
3765 [ output in squid text log format as used by log_mime_hdrs
3766 # output in URL quoted format
3771 width minimum and/or maximum field width:
3772 [width_min][.width_max]
3773 When minimum starts with 0, the field is zero-padded.
3774 String values exceeding maximum width are truncated.
3776 {arg} argument such as header name etc
3780 % a literal % character
3781 sn Unique sequence number per log line entry
3782 err_code The ID of an error response served by Squid or
3783 a similar internal error identifier.
3784 err_detail Additional err_code-dependent error information.
3785 note The annotation specified by the argument. Also
3786 logs the adaptation meta headers set by the
3787 adaptation_meta configuration parameter.
3788 If no argument given all annotations logged.
3789 The argument may include a separator to use with
3792 By default, multiple note values are separated with ","
3793 and multiple notes are separated with "\r\n".
3794 When logging named notes with %{name}note, the
3795 explicitly configured separator is used between note
3796 values. When logging all notes with %note, the
3797 explicitly configured separator is used between
3798 individual notes. There is currently no way to
3799 specify both value and notes separators when logging
3800 all notes with %note.
3802 Connection related format codes:
3804 >a Client source IP address
3806 >p Client source port
3807 >eui Client source EUI (MAC address, EUI-48 or EUI-64 identifier)
3808 >la Local IP address the client connected to
3809 >lp Local port number the client connected to
3810 >qos Client connection TOS/DSCP value set by Squid
3811 >nfmark Client connection netfilter mark set by Squid
3813 la Local listening IP address the client connection was connected to.
3814 lp Local listening port number the client connection was connected to.
3816 <a Server IP address of the last server or peer connection
3817 <A Server FQDN or peer name
3818 <p Server port number of the last server or peer connection
3819 <la Local IP address of the last server or peer connection
3820 <lp Local port number of the last server or peer connection
3821 <qos Server connection TOS/DSCP value set by Squid
3822 <nfmark Server connection netfilter mark set by Squid
3824 Time related format codes:
3826 ts Seconds since epoch
3827 tu subsecond time (milliseconds)
3828 tl Local time. Optional strftime format argument
3829 default %d/%b/%Y:%H:%M:%S %z
3830 tg GMT time. Optional strftime format argument
3831 default %d/%b/%Y:%H:%M:%S %z
3832 tr Response time (milliseconds)
3833 dt Total time spent making DNS lookups (milliseconds)
3834 tS Approximate master transaction start time in
3835 <full seconds since epoch>.<fractional seconds> format.
3836 Currently, Squid considers the master transaction
3837 started when a complete HTTP request header initiating
3838 the transaction is received from the client. This is
3839 the same value that Squid uses to calculate transaction
3840 response time when logging %tr to access.log. Currently,
3841 Squid uses millisecond resolution for %tS values,
3842 similar to the default access.log "current time" field
3845 Access Control related format codes:
3847 et Tag returned by external acl
3848 ea Log string returned by external acl
3849 un User name (any available)
3850 ul User name from authentication
3851 ue User name from external acl helper
3852 ui User name from ident
3853 us User name from SSL
3854 credentials Client credentials. The exact meaning depends on
3855 the authentication scheme: For Basic authentication,
3856 it is the password; for Digest, the realm sent by the
3857 client; for NTLM and Negotiate, the client challenge
3858 or client credentials prefixed with "YR " or "KK ".
3860 HTTP related format codes:
3864 [http::]rm Request method (GET/POST etc)
3865 [http::]>rm Request method from client
3866 [http::]<rm Request method sent to server or peer
3867 [http::]ru Request URL from client (historic, filtered for logging)
3868 [http::]>ru Request URL from client
3869 [http::]<ru Request URL sent to server or peer
3870 [http::]>rs Request URL scheme from client
3871 [http::]<rs Request URL scheme sent to server or peer
3872 [http::]>rd Request URL domain from client
3873 [http::]>rd Request URL domain sent to server or peer
3874 [http::]>rP Request URL port from client
3875 [http::]<rP Request URL port sent to server or peer
3876 [http::]rp Request URL path excluding hostname
3877 [http::]>rp Request URL path excluding hostname from client
3878 [http::]<rp Request URL path excluding hostname sent to server or peer
3879 [http::]rv Request protocol version
3880 [http::]>rv Request protocol version from client
3881 [http::]<rv Request protocol version sent to server or peer
3883 [http::]>h Original received request header.
3884 Usually differs from the request header sent by
3885 Squid, although most fields are often preserved.
3886 Accepts optional header field name/value filter
3887 argument using name[:[separator]element] format.
3888 [http::]>ha Received request header after adaptation and
3889 redirection (pre-cache REQMOD vectoring point).
3890 Usually differs from the request header sent by
3891 Squid, although most fields are often preserved.
3892 Optional header name argument as for >h
3897 [http::]<Hs HTTP status code received from the next hop
3898 [http::]>Hs HTTP status code sent to the client
3900 [http::]<h Reply header. Optional header name argument
3903 [http::]mt MIME content type
3908 [http::]st Total size of request + reply traffic with client
3909 [http::]>st Total size of request received from client.
3910 Excluding chunked encoding bytes.
3911 [http::]<st Total size of reply sent to client (after adaptation)
3913 [http::]>sh Size of request headers received from client
3914 [http::]<sh Size of reply headers sent to client (after adaptation)
3916 [http::]<sH Reply high offset sent
3917 [http::]<sS Upstream object size
3919 [http::]<bs Number of HTTP-equivalent message body bytes
3920 received from the next hop, excluding chunked
3921 transfer encoding and control messages.
3922 Generated FTP/Gopher listings are treated as
3928 [http::]<pt Peer response time in milliseconds. The timer starts
3929 when the last request byte is sent to the next hop
3930 and stops when the last response byte is received.
3931 [http::]<tt Total server-side time in milliseconds. The timer
3932 starts with the first connect request (or write I/O)
3933 sent to the first selected peer. The timer stops
3934 with the last I/O with the last peer.
3936 Squid handling related format codes:
3938 Ss Squid request status (TCP_MISS etc)
3939 Sh Squid hierarchy status (DEFAULT_PARENT etc)
3941 SSL-related format codes:
3943 ssl::bump_mode SslBump decision for the transaction:
3945 For CONNECT requests that initiated bumping of
3946 a connection and for any request received on
3947 an already bumped connection, Squid logs the
3948 corresponding SslBump mode ("server-first" or
3949 "client-first"). See the ssl_bump option for
3950 more information about these modes.
3952 A "none" token is logged for requests that
3953 triggered "ssl_bump" ACL evaluation matching
3954 either a "none" rule or no rules at all.
3956 In all other cases, a single dash ("-") is
3959 If ICAP is enabled, the following code becomes available (as
3960 well as ICAP log codes documented with the icap_log option):
3962 icap::tt Total ICAP processing time for the HTTP
3963 transaction. The timer ticks when ICAP
3964 ACLs are checked and when ICAP
3965 transaction is in progress.
3967 If adaptation is enabled the following three codes become available:
3969 adapt::<last_h The header of the last ICAP response or
3970 meta-information from the last eCAP
3971 transaction related to the HTTP transaction.
3972 Like <h, accepts an optional header name
3975 adapt::sum_trs Summed adaptation transaction response
3976 times recorded as a comma-separated list in
3977 the order of transaction start time. Each time
3978 value is recorded as an integer number,
3979 representing response time of one or more
3980 adaptation (ICAP or eCAP) transaction in
3981 milliseconds. When a failed transaction is
3982 being retried or repeated, its time is not
3983 logged individually but added to the
3984 replacement (next) transaction. See also:
3987 adapt::all_trs All adaptation transaction response times.
3988 Same as adaptation_strs but response times of
3989 individual transactions are never added
3990 together. Instead, all transaction response
3991 times are recorded individually.
3993 You can prefix adapt::*_trs format codes with adaptation
3994 service name in curly braces to record response time(s) specific
3995 to that service. For example: %{my_service}adapt::sum_trs
3997 If SSL is enabled, the following formating codes become available:
3999 %ssl::>cert_subject The Subject field of the received client
4000 SSL certificate or a dash ('-') if Squid has
4001 received an invalid/malformed certificate or
4002 no certificate at all. Consider encoding the
4003 logged value because Subject often has spaces.
4005 %ssl::>cert_issuer The Issuer field of the received client
4006 SSL certificate or a dash ('-') if Squid has
4007 received an invalid/malformed certificate or
4008 no certificate at all. Consider encoding the
4009 logged value because Issuer often has spaces.
4011 The default formats available (which do not need re-defining) are:
4013 logformat squid %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %[un %Sh/%<a %mt
4014 logformat common %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st %Ss:%Sh
4015 logformat combined %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
4016 logformat referrer %ts.%03tu %>a %{Referer}>h %ru
4017 logformat useragent %>a [%tl] "%{User-Agent}>h"
4019 NOTE: When the log_mime_hdrs directive is set to ON.
4020 The squid, common and combined formats have a safely encoded copy
4021 of the mime headers appended to each line within a pair of brackets.
4023 NOTE: The common and combined formats are not quite true to the Apache definition.
4024 The logs from Squid contain an extra status and hierarchy code appended.
4028 NAME: access_log cache_access_log
4030 LOC: Config.Log.accesslogs
4031 DEFAULT_IF_NONE: daemon:@DEFAULT_ACCESS_LOG@ squid
4033 Configures whether and how Squid logs HTTP and ICP transactions.
4034 If access logging is enabled, a single line is logged for every
4035 matching HTTP or ICP request. The recommended directive formats are:
4037 access_log <module>:<place> [option ...] [acl acl ...]
4038 access_log none [acl acl ...]
4040 The following directive format is accepted but may be deprecated:
4041 access_log <module>:<place> [<logformat name> [acl acl ...]]
4043 In most cases, the first ACL name must not contain the '=' character
4044 and should not be equal to an existing logformat name. You can always
4045 start with an 'all' ACL to work around those restrictions.
4047 Will log to the specified module:place using the specified format (which
4048 must be defined in a logformat directive) those entries which match
4049 ALL the acl's specified (which must be defined in acl clauses).
4050 If no acl is specified, all requests will be logged to this destination.
4052 ===== Available options for the recommended directive format =====
4054 logformat=name Names log line format (either built-in or
4055 defined by a logformat directive). Defaults
4058 buffer-size=64KB Defines approximate buffering limit for log
4059 records (see buffered_logs). Squid should not
4060 keep more than the specified size and, hence,
4061 should flush records before the buffer becomes
4062 full to avoid overflows under normal
4063 conditions (the exact flushing algorithm is
4064 module-dependent though). The on-error option
4065 controls overflow handling.
4067 on-error=die|drop Defines action on unrecoverable errors. The
4068 'drop' action ignores (i.e., does not log)
4069 affected log records. The default 'die' action
4070 kills the affected worker. The drop action
4071 support has not been tested for modules other
4074 ===== Modules Currently available =====
4076 none Do not log any requests matching these ACL.
4077 Do not specify Place or logformat name.
4079 stdio Write each log line to disk immediately at the completion of
4081 Place: the filename and path to be written.
4083 daemon Very similar to stdio. But instead of writing to disk the log
4084 line is passed to a daemon helper for asychronous handling instead.
4085 Place: varies depending on the daemon.
4087 log_file_daemon Place: the file name and path to be written.
4089 syslog To log each request via syslog facility.
4090 Place: The syslog facility and priority level for these entries.
4091 Place Format: facility.priority
4093 where facility could be any of:
4094 authpriv, daemon, local0 ... local7 or user.
4096 And priority could be any of:
4097 err, warning, notice, info, debug.
4099 udp To send each log line as text data to a UDP receiver.
4100 Place: The destination host name or IP and port.
4101 Place Format: //host:port
4103 tcp To send each log line as text data to a TCP receiver.
4104 Lines may be accumulated before sending (see buffered_logs).
4105 Place: The destination host name or IP and port.
4106 Place Format: //host:port
4109 access_log daemon:@DEFAULT_ACCESS_LOG@ squid
4115 LOC: Config.Log.icaplogs
4118 ICAP log files record ICAP transaction summaries, one line per
4121 The icap_log option format is:
4122 icap_log <filepath> [<logformat name> [acl acl ...]]
4123 icap_log none [acl acl ...]]
4125 Please see access_log option documentation for details. The two
4126 kinds of logs share the overall configuration approach and many
4129 ICAP processing of a single HTTP message or transaction may
4130 require multiple ICAP transactions. In such cases, multiple
4131 ICAP transaction log lines will correspond to a single access
4134 ICAP log uses logformat codes that make sense for an ICAP
4135 transaction. Header-related codes are applied to the HTTP header
4136 embedded in an ICAP server response, with the following caveats:
4137 For REQMOD, there is no HTTP response header unless the ICAP
4138 server performed request satisfaction. For RESPMOD, the HTTP
4139 request header is the header sent to the ICAP server. For
4140 OPTIONS, there are no HTTP headers.
4142 The following format codes are also available for ICAP logs:
4144 icap::<A ICAP server IP address. Similar to <A.
4146 icap::<service_name ICAP service name from the icap_service
4147 option in Squid configuration file.
4149 icap::ru ICAP Request-URI. Similar to ru.
4151 icap::rm ICAP request method (REQMOD, RESPMOD, or
4152 OPTIONS). Similar to existing rm.
4154 icap::>st Bytes sent to the ICAP server (TCP payload
4155 only; i.e., what Squid writes to the socket).
4157 icap::<st Bytes received from the ICAP server (TCP
4158 payload only; i.e., what Squid reads from
4161 icap::<bs Number of message body bytes received from the
4162 ICAP server. ICAP message body, if any, usually
4163 includes encapsulated HTTP message headers and
4164 possibly encapsulated HTTP message body. The
4165 HTTP body part is dechunked before its size is
4168 icap::tr Transaction response time (in
4169 milliseconds). The timer starts when
4170 the ICAP transaction is created and
4171 stops when the transaction is completed.
4174 icap::tio Transaction I/O time (in milliseconds). The
4175 timer starts when the first ICAP request
4176 byte is scheduled for sending. The timers
4177 stops when the last byte of the ICAP response
4180 icap::to Transaction outcome: ICAP_ERR* for all
4181 transaction errors, ICAP_OPT for OPTION
4182 transactions, ICAP_ECHO for 204
4183 responses, ICAP_MOD for message
4184 modification, and ICAP_SAT for request
4185 satisfaction. Similar to Ss.
4187 icap::Hs ICAP response status code. Similar to Hs.
4189 icap::>h ICAP request header(s). Similar to >h.
4191 icap::<h ICAP response header(s). Similar to <h.
4193 The default ICAP log format, which can be used without an explicit
4194 definition, is called icap_squid:
4196 logformat icap_squid %ts.%03tu %6icap::tr %>a %icap::to/%03icap::Hs %icap::<size %icap::rm %icap::ru% %un -/%icap::<A -
4198 See also: logformat, log_icap, and %adapt::<last_h
4201 NAME: logfile_daemon
4203 DEFAULT: @DEFAULT_LOGFILED@
4204 LOC: Log::TheConfig.logfile_daemon
4206 Specify the path to the logfile-writing daemon. This daemon is
4207 used to write the access and store logs, if configured.
4209 Squid sends a number of commands to the log daemon:
4210 L<data>\n - logfile data
4215 r<n>\n - set rotate count to <n>
4216 b<n>\n - 1 = buffer output, 0 = don't buffer output
4218 No responses is expected.
4224 Remove this line. Use acls with access_log directives to control access logging
4230 Remove this line. Use acls with icap_log directives to control icap logging
4233 NAME: stats_collection
4235 LOC: Config.accessList.stats_collection
4237 DEFAULT_DOC: Allow logging for all transactions.
4238 COMMENT: allow|deny acl acl...
4240 This options allows you to control which requests gets accounted
4241 in performance counters.
4243 This clause only supports fast acl types.
4244 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4247 NAME: cache_store_log
4250 LOC: Config.Log.store
4252 Logs the activities of the storage manager. Shows which
4253 objects are ejected from the cache, and which objects are
4254 saved and for how long.
4255 There are not really utilities to analyze this data, so you can safely
4256 disable it (the default).
4258 Store log uses modular logging outputs. See access_log for the list
4259 of modules supported.
4262 cache_store_log stdio:@DEFAULT_STORE_LOG@
4263 cache_store_log daemon:@DEFAULT_STORE_LOG@
4266 NAME: cache_swap_state cache_swap_log
4268 LOC: Config.Log.swap
4270 DEFAULT_DOC: Store the journal inside its cache_dir
4272 Location for the cache "swap.state" file. This index file holds
4273 the metadata of objects saved on disk. It is used to rebuild
4274 the cache during startup. Normally this file resides in each
4275 'cache_dir' directory, but you may specify an alternate
4276 pathname here. Note you must give a full filename, not just
4277 a directory. Since this is the index for the whole object
4278 list you CANNOT periodically rotate it!
4280 If %s can be used in the file name it will be replaced with a
4281 a representation of the cache_dir name where each / is replaced
4282 with '.'. This is needed to allow adding/removing cache_dir
4283 lines when cache_swap_log is being used.
4285 If have more than one 'cache_dir', and %s is not used in the name
4286 these swap logs will have names such as:
4292 The numbered extension (which is added automatically)
4293 corresponds to the order of the 'cache_dir' lines in this
4294 configuration file. If you change the order of the 'cache_dir'
4295 lines in this file, these index files will NOT correspond to
4296 the correct 'cache_dir' entry (unless you manually rename
4297 them). We recommend you do NOT use this option. It is
4298 better to keep these index files in each 'cache_dir' directory.
4301 NAME: logfile_rotate
4304 LOC: Config.Log.rotateNumber
4306 Specifies the number of logfile rotations to make when you
4307 type 'squid -k rotate'. The default is 10, which will rotate
4308 with extensions 0 through 9. Setting logfile_rotate to 0 will
4309 disable the file name rotation, but the logfiles are still closed
4310 and re-opened. This will enable you to rename the logfiles
4311 yourself just before sending the rotate signal.
4313 Note, the 'squid -k rotate' command normally sends a USR1
4314 signal to the running squid process. In certain situations
4315 (e.g. on Linux with Async I/O), USR1 is used for other
4316 purposes, so -k rotate uses another signal. It is best to get
4317 in the habit of using 'squid -k rotate' instead of 'kill -USR1
4320 Note, from Squid-3.1 this option is only a default for cache.log,
4321 that log can be rotated separately by using debug_options.
4324 NAME: emulate_httpd_log
4327 Replace this with an access_log directive using the format 'common' or 'combined'.
4330 NAME: log_ip_on_direct
4333 Remove this option from your config. To log server or peer names use %<A in the log format.
4338 DEFAULT: @DEFAULT_MIME_TABLE@
4339 LOC: Config.mimeTablePathname
4341 Path to Squid's icon configuration file.
4343 You shouldn't need to change this, but the default file contains
4344 examples and formatting information if you do.
4350 LOC: Config.onoff.log_mime_hdrs
4353 The Cache can record both the request and the response MIME
4354 headers for each HTTP transaction. The headers are encoded
4355 safely and will appear as two bracketed fields at the end of
4356 the access log (for either the native or httpd-emulated log
4357 formats). To enable this logging set log_mime_hdrs to 'on'.
4363 Replace this with an access_log directive using the format 'useragent'.
4366 NAME: referer_log referrer_log
4369 Replace this with an access_log directive using the format 'referrer'.
4374 DEFAULT: @DEFAULT_PID_FILE@
4375 LOC: Config.pidFilename
4377 A filename to write the process-id to. To disable, enter "none".
4383 Remove this option from your config. To log FQDN use %>A in the log format.
4386 NAME: client_netmask
4388 LOC: Config.Addrs.client_netmask
4390 DEFAULT_DOC: Log full client IP address
4392 A netmask for client addresses in logfiles and cachemgr output.
4393 Change this to protect the privacy of your cache clients.
4394 A netmask of 255.255.255.0 will log all IP's in that range with
4395 the last digit set to '0'.
4401 Use a regular access.log with ACL limiting it to MISS events.
4404 NAME: strip_query_terms
4406 LOC: Config.onoff.strip_query_terms
4409 By default, Squid strips query terms from requested URLs before
4410 logging. This protects your user's privacy and reduces log size.
4412 When investigating HIT/MISS or other caching behaviour you
4413 will need to disable this to see the full URL used by Squid.
4420 LOC: Config.onoff.buffered_logs
4422 Whether to write/send access_log records ASAP or accumulate them and
4423 then write/send them in larger chunks. Buffering may improve
4424 performance because it decreases the number of I/Os. However,
4425 buffering increases the delay before log records become available to
4426 the final recipient (e.g., a disk file or logging daemon) and,
4427 hence, increases the risk of log records loss.
4429 Note that even when buffered_logs are off, Squid may have to buffer
4430 records if it cannot write/send them immediately due to pending I/Os
4431 (e.g., the I/O writing the previous log record) or connectivity loss.
4433 Currently honored by 'daemon' and 'tcp' access_log modules only.
4436 NAME: netdb_filename
4438 DEFAULT: stdio:@DEFAULT_NETDB_FILE@
4439 LOC: Config.netdbFilename
4442 Where Squid stores it's netdb journal.
4443 When enabled this journal preserves netdb state between restarts.
4445 To disable, enter "none".
4449 OPTIONS FOR TROUBLESHOOTING
4450 -----------------------------------------------------------------------------
4455 DEFAULT_IF_NONE: @DEFAULT_CACHE_LOG@
4456 LOC: Debug::cache_log
4458 Squid administrative logging file.
4460 This is where general information about Squid behavior goes. You can
4461 increase the amount of data logged to this file and how often it is
4462 rotated with "debug_options"
4468 DEFAULT_DOC: Log all critical and important messages.
4469 LOC: Debug::debugOptions
4471 Logging options are set as section,level where each source file
4472 is assigned a unique section. Lower levels result in less
4473 output, Full debugging (level 9) can result in a very large
4474 log file, so be careful.
4476 The magic word "ALL" sets debugging levels for all sections.
4477 The default is to run with "ALL,1" to record important warnings.
4479 The rotate=N option can be used to keep more or less of these logs
4480 than would otherwise be kept by logfile_rotate.
4481 For most uses a single log should be enough to monitor current
4482 events affecting Squid.
4487 LOC: Config.coredump_dir
4488 DEFAULT_IF_NONE: none
4489 DEFAULT_DOC: Use the directory from where Squid was started.
4491 By default Squid leaves core files in the directory from where
4492 it was started. If you set 'coredump_dir' to a directory
4493 that exists, Squid will chdir() to that directory at startup
4494 and coredump files will be left there.
4498 # Leave coredumps in the first cache dir
4499 coredump_dir @DEFAULT_SWAP_DIR@
4505 OPTIONS FOR FTP GATEWAYING
4506 -----------------------------------------------------------------------------
4512 LOC: Config.Ftp.anon_user
4514 If you want the anonymous login password to be more informative
4515 (and enable the use of picky FTP servers), set this to something
4516 reasonable for your domain, like wwwuser@somewhere.net
4518 The reason why this is domainless by default is the
4519 request can be made on the behalf of a user in any domain,
4520 depending on how the cache is used.
4521 Some FTP server also validate the email address is valid
4522 (for example perl.com).
4528 LOC: Config.Ftp.passive
4530 If your firewall does not allow Squid to use passive
4531 connections, turn off this option.
4533 Use of ftp_epsv_all option requires this to be ON.
4539 LOC: Config.Ftp.epsv_all
4541 FTP Protocol extensions permit the use of a special "EPSV ALL" command.
4543 NATs may be able to put the connection on a "fast path" through the
4544 translator, as the EPRT command will never be used and therefore,
4545 translation of the data portion of the segments will never be needed.
4547 When a client only expects to do two-way FTP transfers this may be
4549 If squid finds that it must do a three-way FTP transfer after issuing
4550 an EPSV ALL command, the FTP session will fail.
4552 If you have any doubts about this option do not use it.
4553 Squid will nicely attempt all other connection methods.
4555 Requires ftp_passive to be ON (default) for any effect.
4561 LOC: Config.accessList.ftp_epsv
4563 FTP Protocol extensions permit the use of a special "EPSV" command.
4565 NATs may be able to put the connection on a "fast path" through the
4566 translator using EPSV, as the EPRT command will never be used
4567 and therefore, translation of the data portion of the segments
4568 will never be needed.
4570 EPSV is often required to interoperate with FTP servers on IPv6
4571 networks. On the other hand, it may break some IPv4 servers.
4573 By default, EPSV may try EPSV with any FTP server. To fine tune
4574 that decision, you may restrict EPSV to certain clients or servers
4577 ftp_epsv allow|deny al1 acl2 ...
4579 WARNING: Disabling EPSV may cause problems with external NAT and IPv6.
4581 Only fast ACLs are supported.
4582 Requires ftp_passive to be ON (default) for any effect.
4588 LOC: Config.Ftp.eprt
4590 FTP Protocol extensions permit the use of a special "EPRT" command.
4592 This extension provides a protocol neutral alternative to the
4593 IPv4-only PORT command. When supported it enables active FTP data
4594 channels over IPv6 and efficient NAT handling.
4596 Turning this OFF will prevent EPRT being attempted and will skip
4597 straight to using PORT for IPv4 servers.
4599 Some devices are known to not handle this extension correctly and
4600 may result in crashes. Devices which suport EPRT enough to fail
4601 cleanly will result in Squid attempting PORT anyway. This directive
4602 should only be disabled when EPRT results in device failures.
4604 WARNING: Doing so will convert Squid back to the old behavior with all
4605 the related problems with external NAT devices/layers and IPv4-only FTP.
4608 NAME: ftp_sanitycheck
4611 LOC: Config.Ftp.sanitycheck
4613 For security and data integrity reasons Squid by default performs
4614 sanity checks of the addresses of FTP data connections ensure the
4615 data connection is to the requested server. If you need to allow
4616 FTP connections to servers using another IP address for the data
4617 connection turn this off.
4620 NAME: ftp_telnet_protocol
4623 LOC: Config.Ftp.telnet
4625 The FTP protocol is officially defined to use the telnet protocol
4626 as transport channel for the control connection. However, many
4627 implementations are broken and does not respect this aspect of
4630 If you have trouble accessing files with ASCII code 255 in the
4631 path or similar problems involving this ASCII code you can
4632 try setting this directive to off. If that helps, report to the
4633 operator of the FTP server in question that their FTP server
4634 is broken and does not follow the FTP standard.
4638 OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
4639 -----------------------------------------------------------------------------
4644 DEFAULT: @DEFAULT_DISKD@
4645 LOC: Config.Program.diskd
4647 Specify the location of the diskd executable.
4648 Note this is only useful if you have compiled in
4649 diskd as one of the store io modules.
4652 NAME: unlinkd_program
4655 DEFAULT: @DEFAULT_UNLINKD@
4656 LOC: Config.Program.unlinkd
4658 Specify the location of the executable for file deletion process.
4661 NAME: pinger_program
4663 DEFAULT: @DEFAULT_PINGER@
4664 LOC: Config.pinger.program
4667 Specify the location of the executable for the pinger process.
4673 LOC: Config.pinger.enable
4676 Control whether the pinger is active at run-time.
4677 Enables turning ICMP pinger on and off with a simple
4678 squid -k reconfigure.
4683 OPTIONS FOR URL REWRITING
4684 -----------------------------------------------------------------------------
4687 NAME: url_rewrite_program redirect_program
4689 LOC: Config.Program.redirect
4692 Specify the location of the executable URL rewriter to use.
4693 Since they can perform almost any function there isn't one included.
4695 For each requested URL, the rewriter will receive on line with the format
4697 [channel-ID <SP>] URL [<SP> extras]<NL>
4700 After processing the request the helper must reply using the following format:
4702 [channel-ID <SP>] result [<SP> kv-pairs]
4704 The result code can be:
4706 OK status=30N url="..."
4707 Redirect the URL to the one supplied in 'url='.
4708 'status=' is optional and contains the status code to send
4709 the client in Squids HTTP response. It must be one of the
4710 HTTP redirect status codes: 301, 302, 303, 307, 308.
4711 When no status is given Squid will use 302.
4713 OK rewrite-url="..."
4714 Rewrite the URL to the one supplied in 'rewrite-url='.
4715 The new URL is fetched directly by Squid and returned to
4716 the client as the response to its request.
4719 When neither of url= and rewrite-url= are sent Squid does
4723 Do not change the URL.
4726 An internal error occurred in the helper, preventing
4727 a result being identified. The 'message=' key name is
4728 reserved for delivering a log message.
4731 In the future, the interface protocol will be extended with
4732 key=value pairs ("kv-pairs" shown above). Helper programs
4733 should be prepared to receive and possibly ignore additional
4734 whitespace-separated tokens on each input line.
4736 When using the concurrency= option the protocol is changed by
4737 introducing a query channel tag in front of the request/response.
4738 The query channel tag is a number between 0 and concurrency-1.
4739 This value must be echoed back unchanged to Squid as the first part
4740 of the response relating to its request.
4742 WARNING: URL re-writing ability should be avoided whenever possible.
4743 Use the URL redirect form of response instead.
4745 Re-write creates a difference in the state held by the client
4746 and server. Possibly causing confusion when the server response
4747 contains snippets of its view state. Embeded URLs, response
4748 and content Location headers, etc. are not re-written by this
4751 By default, a URL rewriter is not used.
4754 NAME: url_rewrite_children redirect_children
4755 TYPE: HelperChildConfig
4756 DEFAULT: 20 startup=0 idle=1 concurrency=0
4757 LOC: Config.redirectChildren
4759 The maximum number of redirector processes to spawn. If you limit
4760 it too few Squid will have to wait for them to process a backlog of
4761 URLs, slowing it down. If you allow too many they will use RAM
4762 and other system resources noticably.
4764 The startup= and idle= options allow some measure of skew in your
4769 Sets a minimum of how many processes are to be spawned when Squid
4770 starts or reconfigures. When set to zero the first request will
4771 cause spawning of the first child process to handle it.
4773 Starting too few will cause an initial slowdown in traffic as Squid
4774 attempts to simultaneously spawn enough processes to cope.
4778 Sets a minimum of how many processes Squid is to try and keep available
4779 at all times. When traffic begins to rise above what the existing
4780 processes can handle this many more will be spawned up to the maximum
4781 configured. A minimum setting of 1 is required.
4785 The number of requests each redirector helper can handle in
4786 parallel. Defaults to 0 which indicates the redirector
4787 is a old-style single threaded redirector.
4789 When this directive is set to a value >= 1 then the protocol
4790 used to communicate with the helper is modified to include
4791 an ID in front of the request/response. The ID from the request
4792 must be echoed back with the response to that request.
4795 NAME: url_rewrite_host_header redirect_rewrites_host_header
4798 LOC: Config.onoff.redir_rewrites_host
4800 To preserve same-origin security policies in browsers and
4801 prevent Host: header forgery by redirectors Squid rewrites
4802 any Host: header in redirected requests.
4804 If you are running an accelerator this may not be a wanted
4805 effect of a redirector. This directive enables you disable
4806 Host: alteration in reverse-proxy traffic.
4808 WARNING: Entries are cached on the result of the URL rewriting
4809 process, so be careful if you have domain-virtual hosts.
4811 WARNING: Squid and other software verifies the URL and Host
4812 are matching, so be careful not to relay through other proxies
4813 or inspecting firewalls with this disabled.
4816 NAME: url_rewrite_access redirector_access
4819 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
4820 LOC: Config.accessList.redirector
4822 If defined, this access list specifies which requests are
4823 sent to the redirector processes.
4825 This clause supports both fast and slow acl types.
4826 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4829 NAME: url_rewrite_bypass redirector_bypass
4831 LOC: Config.onoff.redirector_bypass
4834 When this is 'on', a request will not go through the
4835 redirector if all the helpers are busy. If this is 'off'
4836 and the redirector queue grows too large, Squid will exit
4837 with a FATAL error and ask you to increase the number of
4838 redirectors. You should only enable this if the redirectors
4839 are not critical to your caching system. If you use
4840 redirectors for access control, and you enable this option,
4841 users may have access to pages they should not
4842 be allowed to request.
4845 NAME: url_rewrite_extras
4846 TYPE: TokenOrQuotedString
4847 LOC: Config.redirector_extras
4848 DEFAULT: "%>a/%>A %un %>rm myip=%la myport=%lp"
4850 Specifies a string to be append to request line format for the
4851 rewriter helper. "Quoted" format values may contain spaces and
4852 logformat %macros. In theory, any logformat %macro can be used.
4853 In practice, a %macro expands as a dash (-) if the helper request is
4854 sent before the required macro information is available to Squid.
4858 OPTIONS FOR STORE ID
4859 -----------------------------------------------------------------------------
4862 NAME: store_id_program storeurl_rewrite_program
4864 LOC: Config.Program.store_id
4867 Specify the location of the executable StoreID helper to use.
4868 Since they can perform almost any function there isn't one included.
4870 For each requested URL, the helper will receive one line with the format
4872 [channel-ID <SP>] URL [<SP> extras]<NL>
4875 After processing the request the helper must reply using the following format:
4877 [channel-ID <SP>] result [<SP> kv-pairs]
4879 The result code can be:
4882 Use the StoreID supplied in 'store-id='.
4885 The default is to use HTTP request URL as the store ID.
4888 An internal error occured in the helper, preventing
4889 a result being identified.
4892 Helper programs should be prepared to receive and possibly ignore
4893 additional whitespace-separated tokens on each input line.
4895 When using the concurrency= option the protocol is changed by
4896 introducing a query channel tag in front of the request/response.
4897 The query channel tag is a number between 0 and concurrency-1.
4898 This value must be echoed back unchanged to Squid as the first part
4899 of the response relating to its request.
4901 NOTE: when using StoreID refresh_pattern will apply to the StoreID
4902 returned from the helper and not the URL.
4904 WARNING: Wrong StoreID value returned by a careless helper may result
4905 in the wrong cached response returned to the user.
4907 By default, a StoreID helper is not used.
4910 NAME: store_id_extras
4911 TYPE: TokenOrQuotedString
4912 LOC: Config.storeId_extras
4913 DEFAULT: "%>a/%>A %un %>rm myip=%la myport=%lp"
4915 Specifies a string to be append to request line format for the
4916 StoreId helper. "Quoted" format values may contain spaces and
4917 logformat %macros. In theory, any logformat %macro can be used.
4918 In practice, a %macro expands as a dash (-) if the helper request is
4919 sent before the required macro information is available to Squid.
4922 NAME: store_id_children storeurl_rewrite_children
4923 TYPE: HelperChildConfig
4924 DEFAULT: 20 startup=0 idle=1 concurrency=0
4925 LOC: Config.storeIdChildren
4927 The maximum number of StoreID helper processes to spawn. If you limit
4928 it too few Squid will have to wait for them to process a backlog of
4929 requests, slowing it down. If you allow too many they will use RAM
4930 and other system resources noticably.
4932 The startup= and idle= options allow some measure of skew in your
4937 Sets a minimum of how many processes are to be spawned when Squid
4938 starts or reconfigures. When set to zero the first request will
4939 cause spawning of the first child process to handle it.
4941 Starting too few will cause an initial slowdown in traffic as Squid
4942 attempts to simultaneously spawn enough processes to cope.
4946 Sets a minimum of how many processes Squid is to try and keep available
4947 at all times. When traffic begins to rise above what the existing
4948 processes can handle this many more will be spawned up to the maximum
4949 configured. A minimum setting of 1 is required.
4953 The number of requests each storeID helper can handle in
4954 parallel. Defaults to 0 which indicates the helper
4955 is a old-style single threaded program.
4957 When this directive is set to a value >= 1 then the protocol
4958 used to communicate with the helper is modified to include
4959 an ID in front of the request/response. The ID from the request
4960 must be echoed back with the response to that request.
4963 NAME: store_id_access storeurl_rewrite_access
4966 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
4967 LOC: Config.accessList.store_id
4969 If defined, this access list specifies which requests are
4970 sent to the StoreID processes. By default all requests
4973 This clause supports both fast and slow acl types.
4974 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4977 NAME: store_id_bypass storeurl_rewrite_bypass
4979 LOC: Config.onoff.store_id_bypass
4982 When this is 'on', a request will not go through the
4983 helper if all helpers are busy. If this is 'off'
4984 and the helper queue grows too large, Squid will exit
4985 with a FATAL error and ask you to increase the number of
4986 helpers. You should only enable this if the helperss
4987 are not critical to your caching system. If you use
4988 helpers for critical caching components, and you enable this
4989 option, users may not get objects from cache.
4993 OPTIONS FOR TUNING THE CACHE
4994 -----------------------------------------------------------------------------
4997 NAME: cache no_cache
5000 DEFAULT_DOC: By default, this directive is unused and has no effect.
5001 LOC: Config.accessList.noCache
5003 Requests denied by this directive will not be served from the cache
5004 and their responses will not be stored in the cache. This directive
5005 has no effect on other transactions and on already cached responses.
5007 This clause supports both fast and slow acl types.
5008 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5010 This and the two other similar caching directives listed below are
5011 checked at different transaction processing stages, have different
5012 access to response information, affect different cache operations,
5013 and differ in slow ACLs support:
5015 * cache: Checked before Squid makes a hit/miss determination.
5016 No access to reply information!
5017 Denies both serving a hit and storing a miss.
5018 Supports both fast and slow ACLs.
5019 * send_hit: Checked after a hit was detected.
5020 Has access to reply (hit) information.
5021 Denies serving a hit only.
5022 Supports fast ACLs only.
5023 * store_miss: Checked before storing a cachable miss.
5024 Has access to reply (miss) information.
5025 Denies storing a miss only.
5026 Supports fast ACLs only.
5028 If you are not sure which of the three directives to use, apply the
5029 following decision logic:
5031 * If your ACL(s) are of slow type _and_ need response info, redesign.
5032 Squid does not support that particular combination at this time.
5034 * If your directive ACL(s) are of slow type, use "cache"; and/or
5035 * if your directive ACL(s) need no response info, use "cache".
5037 * If you do not want the response cached, use store_miss; and/or
5038 * if you do not want a hit on a cached response, use send_hit.
5044 DEFAULT_DOC: By default, this directive is unused and has no effect.
5045 LOC: Config.accessList.sendHit
5047 Responses denied by this directive will not be served from the cache
5048 (but may still be cached, see store_miss). This directive has no
5049 effect on the responses it allows and on the cached objects.
5051 Please see the "cache" directive for a summary of differences among
5052 store_miss, send_hit, and cache directives.
5054 Unlike the "cache" directive, send_hit only supports fast acl
5055 types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5059 # apply custom Store ID mapping to some URLs
5060 acl MapMe dstdomain .c.example.com
5061 store_id_program ...
5062 store_id_access allow MapMe
5064 # but prevent caching of special responses
5065 # such as 302 redirects that cause StoreID loops
5066 acl Ordinary http_status 200-299
5067 store_miss deny MapMe !Ordinary
5069 # and do not serve any previously stored special responses
5070 # from the cache (in case they were already cached before
5071 # the above store_miss rule was in effect).
5072 send_hit deny MapMe !Ordinary
5078 DEFAULT_DOC: By default, this directive is unused and has no effect.
5079 LOC: Config.accessList.storeMiss
5081 Responses denied by this directive will not be cached (but may still
5082 be served from the cache, see send_hit). This directive has no
5083 effect on the responses it allows and on the already cached responses.
5085 Please see the "cache" directive for a summary of differences among
5086 store_miss, send_hit, and cache directives. See the
5087 send_hit directive for a usage example.
5089 Unlike the "cache" directive, store_miss only supports fast acl
5090 types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5096 LOC: Config.maxStale
5099 This option puts an upper limit on how stale content Squid
5100 will serve from the cache if cache validation fails.
5101 Can be overriden by the refresh_pattern max-stale option.
5104 NAME: refresh_pattern
5105 TYPE: refreshpattern
5109 usage: refresh_pattern [-i] regex min percent max [options]
5111 By default, regular expressions are CASE-SENSITIVE. To make
5112 them case-insensitive, use the -i option.
5114 'Min' is the time (in minutes) an object without an explicit
5115 expiry time should be considered fresh. The recommended
5116 value is 0, any higher values may cause dynamic applications
5117 to be erroneously cached unless the application designer
5118 has taken the appropriate actions.
5120 'Percent' is a percentage of the objects age (time since last
5121 modification age) an object without explicit expiry time
5122 will be considered fresh.
5124 'Max' is an upper limit on how long objects without an explicit
5125 expiry time will be considered fresh.
5127 options: override-expire
5132 ignore-must-revalidate
5139 override-expire enforces min age even if the server
5140 sent an explicit expiry time (e.g., with the
5141 Expires: header or Cache-Control: max-age). Doing this
5142 VIOLATES the HTTP standard. Enabling this feature
5143 could make you liable for problems which it causes.
5145 Note: override-expire does not enforce staleness - it only extends
5146 freshness / min. If the server returns a Expires time which
5147 is longer than your max time, Squid will still consider
5148 the object fresh for that period of time.
5150 override-lastmod enforces min age even on objects
5151 that were modified recently.
5153 reload-into-ims changes a client no-cache or ``reload''
5154 request for a cached entry into a conditional request using
5155 If-Modified-Since and/or If-None-Match headers, provided the
5156 cached entry has a Last-Modified and/or a strong ETag header.
5157 Doing this VIOLATES the HTTP standard. Enabling this feature
5158 could make you liable for problems which it causes.
5160 ignore-reload ignores a client no-cache or ``reload''
5161 header. Doing this VIOLATES the HTTP standard. Enabling
5162 this feature could make you liable for problems which
5165 ignore-no-store ignores any ``Cache-control: no-store''
5166 headers received from a server. Doing this VIOLATES
5167 the HTTP standard. Enabling this feature could make you
5168 liable for problems which it causes.
5170 ignore-must-revalidate ignores any ``Cache-Control: must-revalidate``
5171 headers received from a server. Doing this VIOLATES
5172 the HTTP standard. Enabling this feature could make you
5173 liable for problems which it causes.
5175 ignore-private ignores any ``Cache-control: private''
5176 headers received from a server. Doing this VIOLATES
5177 the HTTP standard. Enabling this feature could make you
5178 liable for problems which it causes.
5180 ignore-auth caches responses to requests with authorization,
5181 as if the originserver had sent ``Cache-control: public''
5182 in the response header. Doing this VIOLATES the HTTP standard.
5183 Enabling this feature could make you liable for problems which
5186 refresh-ims causes squid to contact the origin server
5187 when a client issues an If-Modified-Since request. This
5188 ensures that the client will receive an updated version
5189 if one is available.
5191 store-stale stores responses even if they don't have explicit
5192 freshness or a validator (i.e., Last-Modified or an ETag)
5193 present, or if they're already stale. By default, Squid will
5194 not cache such responses because they usually can't be
5195 reused. Note that such responses will be stale by default.
5197 max-stale=NN provide a maximum staleness factor. Squid won't
5198 serve objects more stale than this even if it failed to
5199 validate the object. Default: use the max_stale global limit.
5201 Basically a cached object is:
5203 FRESH if expires < now, else STALE
5205 FRESH if lm-factor < percent, else STALE
5209 The refresh_pattern lines are checked in the order listed here.
5210 The first entry which matches is used. If none of the entries
5211 match the default will be used.
5213 Note, you must uncomment all the default lines if you want
5214 to change one. The default setting is only active if none is
5220 # Add any of your own refresh_pattern entries above these.
5222 refresh_pattern ^ftp: 1440 20% 10080
5223 refresh_pattern ^gopher: 1440 0% 1440
5224 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0
5225 refresh_pattern . 0 20% 4320
5229 NAME: quick_abort_min
5233 LOC: Config.quickAbort.min
5236 NAME: quick_abort_max
5240 LOC: Config.quickAbort.max
5243 NAME: quick_abort_pct
5247 LOC: Config.quickAbort.pct
5249 The cache by default continues downloading aborted requests
5250 which are almost completed (less than 16 KB remaining). This
5251 may be undesirable on slow (e.g. SLIP) links and/or very busy
5252 caches. Impatient users may tie up file descriptors and
5253 bandwidth by repeatedly requesting and immediately aborting
5256 When the user aborts a request, Squid will check the
5257 quick_abort values to the amount of data transfered until
5260 If the transfer has less than 'quick_abort_min' KB remaining,
5261 it will finish the retrieval.
5263 If the transfer has more than 'quick_abort_max' KB remaining,
5264 it will abort the retrieval.
5266 If more than 'quick_abort_pct' of the transfer has completed,
5267 it will finish the retrieval.
5269 If you do not want any retrieval to continue after the client
5270 has aborted, set both 'quick_abort_min' and 'quick_abort_max'
5273 If you want retrievals to always continue if they are being
5274 cached set 'quick_abort_min' to '-1 KB'.
5277 NAME: read_ahead_gap
5278 COMMENT: buffer-size
5280 LOC: Config.readAheadGap
5283 The amount of data the cache will buffer ahead of what has been
5284 sent to the client when retrieving an object from another server.
5288 IFDEF: USE_HTTP_VIOLATIONS
5291 LOC: Config.negativeTtl
5294 Set the Default Time-to-Live (TTL) for failed requests.
5295 Certain types of failures (such as "connection refused" and
5296 "404 Not Found") are able to be negatively-cached for a short time.
5297 Modern web servers should provide Expires: header, however if they
5298 do not this can provide a minimum TTL.
5299 The default is not to cache errors with unknown expiry details.
5301 Note that this is different from negative caching of DNS lookups.
5303 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5304 this feature could make you liable for problems which it
5308 NAME: positive_dns_ttl
5311 LOC: Config.positiveDnsTtl
5314 Upper limit on how long Squid will cache positive DNS responses.
5315 Default is 6 hours (360 minutes). This directive must be set
5316 larger than negative_dns_ttl.
5319 NAME: negative_dns_ttl
5322 LOC: Config.negativeDnsTtl
5325 Time-to-Live (TTL) for negative caching of failed DNS lookups.
5326 This also sets the lower cache limit on positive lookups.
5327 Minimum value is 1 second, and it is not recommendable to go
5328 much below 10 seconds.
5331 NAME: range_offset_limit
5332 COMMENT: size [acl acl...]
5334 LOC: Config.rangeOffsetLimit
5337 usage: (size) [units] [[!]aclname]
5339 Sets an upper limit on how far (number of bytes) into the file
5340 a Range request may be to cause Squid to prefetch the whole file.
5341 If beyond this limit, Squid forwards the Range request as it is and
5342 the result is NOT cached.
5344 This is to stop a far ahead range request (lets say start at 17MB)
5345 from making Squid fetch the whole object up to that point before
5346 sending anything to the client.
5348 Multiple range_offset_limit lines may be specified, and they will
5349 be searched from top to bottom on each request until a match is found.
5350 The first match found will be used. If no line matches a request, the
5351 default limit of 0 bytes will be used.
5353 'size' is the limit specified as a number of units.
5355 'units' specifies whether to use bytes, KB, MB, etc.
5356 If no units are specified bytes are assumed.
5358 A size of 0 causes Squid to never fetch more than the
5359 client requested. (default)
5361 A size of 'none' causes Squid to always fetch the object from the
5362 beginning so it may cache the result. (2.0 style)
5364 'aclname' is the name of a defined ACL.
5366 NP: Using 'none' as the byte value here will override any quick_abort settings
5367 that may otherwise apply to the range request. The range request will
5368 be fully fetched from start to finish regardless of the client
5369 actions. This affects bandwidth usage.
5372 NAME: minimum_expiry_time
5375 LOC: Config.minimum_expiry_time
5378 The minimum caching time according to (Expires - Date)
5379 headers Squid honors if the object can't be revalidated.
5380 The default is 60 seconds.
5382 In reverse proxy environments it might be desirable to honor
5383 shorter object lifetimes. It is most likely better to make
5384 your server return a meaningful Last-Modified header however.
5386 In ESI environments where page fragments often have short
5387 lifetimes, this will often be best set to 0.
5390 NAME: store_avg_object_size
5394 LOC: Config.Store.avgObjectSize
5396 Average object size, used to estimate number of objects your
5397 cache can hold. The default is 13 KB.
5399 This is used to pre-seed the cache index memory allocation to
5400 reduce expensive reallocate operations while handling clients
5401 traffic. Too-large values may result in memory allocation during
5402 peak traffic, too-small values will result in wasted memory.
5404 Check the cache manager 'info' report metrics for the real
5405 object sizes seen by your Squid before tuning this.
5408 NAME: store_objects_per_bucket
5411 LOC: Config.Store.objectsPerBucket
5413 Target number of objects per bucket in the store hash table.
5414 Lowering this value increases the total number of buckets and
5415 also the storage maintenance rate. The default is 20.
5420 -----------------------------------------------------------------------------
5423 NAME: request_header_max_size
5427 LOC: Config.maxRequestHeaderSize
5429 This specifies the maximum size for HTTP headers in a request.
5430 Request headers are usually relatively small (about 512 bytes).
5431 Placing a limit on the request header size will catch certain
5432 bugs (for example with persistent connections) and possibly
5433 buffer-overflow or denial-of-service attacks.
5436 NAME: reply_header_max_size
5440 LOC: Config.maxReplyHeaderSize
5442 This specifies the maximum size for HTTP headers in a reply.
5443 Reply headers are usually relatively small (about 512 bytes).
5444 Placing a limit on the reply header size will catch certain
5445 bugs (for example with persistent connections) and possibly
5446 buffer-overflow or denial-of-service attacks.
5449 NAME: request_body_max_size
5453 DEFAULT_DOC: No limit.
5454 LOC: Config.maxRequestBodySize
5456 This specifies the maximum size for an HTTP request body.
5457 In other words, the maximum size of a PUT/POST request.
5458 A user who attempts to send a request with a body larger
5459 than this limit receives an "Invalid Request" error message.
5460 If you set this parameter to a zero (the default), there will
5461 be no limit imposed.
5463 See also client_request_buffer_max_size for an alternative
5464 limitation on client uploads which can be configured.
5467 NAME: client_request_buffer_max_size
5471 LOC: Config.maxRequestBufferSize
5473 This specifies the maximum buffer size of a client request.
5474 It prevents squid eating too much memory when somebody uploads
5478 NAME: chunked_request_body_max_size
5482 LOC: Config.maxChunkedRequestBodySize
5484 A broken or confused HTTP/1.1 client may send a chunked HTTP
5485 request to Squid. Squid does not have full support for that
5486 feature yet. To cope with such requests, Squid buffers the
5487 entire request and then dechunks request body to create a
5488 plain HTTP/1.0 request with a known content length. The plain
5489 request is then used by the rest of Squid code as usual.
5491 The option value specifies the maximum size of the buffer used
5492 to hold the request before the conversion. If the chunked
5493 request size exceeds the specified limit, the conversion
5494 fails, and the client receives an "unsupported request" error,
5495 as if dechunking was disabled.
5497 Dechunking is enabled by default. To disable conversion of
5498 chunked requests, set the maximum to zero.
5500 Request dechunking feature and this option in particular are a
5501 temporary hack. When chunking requests and responses are fully
5502 supported, there will be no need to buffer a chunked request.
5506 IFDEF: USE_HTTP_VIOLATIONS
5509 DEFAULT_DOC: Obey RFC 2616.
5510 LOC: Config.accessList.brokenPosts
5512 A list of ACL elements which, if matched, causes Squid to send
5513 an extra CRLF pair after the body of a PUT/POST request.
5515 Some HTTP servers has broken implementations of PUT/POST,
5516 and rely on an extra CRLF pair sent by some WWW clients.
5518 Quote from RFC2616 section 4.1 on this matter:
5520 Note: certain buggy HTTP/1.0 client implementations generate an
5521 extra CRLF's after a POST request. To restate what is explicitly
5522 forbidden by the BNF, an HTTP/1.1 client must not preface or follow
5523 a request with an extra CRLF.
5525 This clause only supports fast acl types.
5526 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5529 acl buggy_server url_regex ^http://....
5530 broken_posts allow buggy_server
5533 NAME: adaptation_uses_indirect_client icap_uses_indirect_client
5536 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_ADAPTATION
5538 LOC: Adaptation::Config::use_indirect_client
5540 Controls whether the indirect client IP address (instead of the direct
5541 client IP address) is passed to adaptation services.
5543 See also: follow_x_forwarded_for adaptation_send_client_ip
5547 IFDEF: USE_HTTP_VIOLATIONS
5551 LOC: Config.onoff.via
5553 If set (default), Squid will include a Via header in requests and
5554 replies as required by RFC2616.
5560 LOC: Config.onoff.ie_refresh
5563 Microsoft Internet Explorer up until version 5.5 Service
5564 Pack 1 has an issue with transparent proxies, wherein it
5565 is impossible to force a refresh. Turning this on provides
5566 a partial fix to the problem, by causing all IMS-REFRESH
5567 requests from older IE versions to check the origin server
5568 for fresh content. This reduces hit ratio by some amount
5569 (~10% in my experience), but allows users to actually get
5570 fresh content when they want it. Note because Squid
5571 cannot tell if the user is using 5.5 or 5.5SP1, the behavior
5572 of 5.5 is unchanged from old versions of Squid (i.e. a
5573 forced refresh is impossible). Newer versions of IE will,
5574 hopefully, continue to have the new behavior and will be
5575 handled based on that assumption. This option defaults to
5576 the old Squid behavior, which is better for hit ratios but
5577 worse for clients using IE, if they need to be able to
5578 force fresh content.
5581 NAME: vary_ignore_expire
5584 LOC: Config.onoff.vary_ignore_expire
5587 Many HTTP servers supporting Vary gives such objects
5588 immediate expiry time with no cache-control header
5589 when requested by a HTTP/1.0 client. This option
5590 enables Squid to ignore such expiry times until
5591 HTTP/1.1 is fully implemented.
5593 WARNING: If turned on this may eventually cause some
5594 varying objects not intended for caching to get cached.
5597 NAME: request_entities
5599 LOC: Config.onoff.request_entities
5602 Squid defaults to deny GET and HEAD requests with request entities,
5603 as the meaning of such requests are undefined in the HTTP standard
5604 even if not explicitly forbidden.
5606 Set this directive to on if you have clients which insists
5607 on sending request entities in GET or HEAD requests. But be warned
5608 that there is server software (both proxies and web servers) which
5609 can fail to properly process this kind of request which may make you
5610 vulnerable to cache pollution attacks if enabled.
5613 NAME: request_header_access
5614 IFDEF: USE_HTTP_VIOLATIONS
5615 TYPE: http_header_access
5616 LOC: Config.request_header_access
5618 DEFAULT_DOC: No limits.
5620 Usage: request_header_access header_name allow|deny [!]aclname ...
5622 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5623 this feature could make you liable for problems which it
5626 This option replaces the old 'anonymize_headers' and the
5627 older 'http_anonymizer' option with something that is much
5628 more configurable. A list of ACLs for each header name allows
5629 removal of specific header fields under specific conditions.
5631 This option only applies to outgoing HTTP request headers (i.e.,
5632 headers sent by Squid to the next HTTP hop such as a cache peer
5633 or an origin server). The option has no effect during cache hit
5634 detection. The equivalent adaptation vectoring point in ICAP
5635 terminology is post-cache REQMOD.
5637 The option is applied to individual outgoing request header
5638 fields. For each request header field F, Squid uses the first
5639 qualifying sets of request_header_access rules:
5641 1. Rules with header_name equal to F's name.
5642 2. Rules with header_name 'Other', provided F's name is not
5643 on the hard-coded list of commonly used HTTP header names.
5644 3. Rules with header_name 'All'.
5646 Within that qualifying rule set, rule ACLs are checked as usual.
5647 If ACLs of an "allow" rule match, the header field is allowed to
5648 go through as is. If ACLs of a "deny" rule match, the header is
5649 removed and request_header_replace is then checked to identify
5650 if the removed header has a replacement. If no rules within the
5651 set have matching ACLs, the header field is left as is.
5653 For example, to achieve the same behavior as the old
5654 'http_anonymizer standard' option, you should use:
5656 request_header_access From deny all
5657 request_header_access Referer deny all
5658 request_header_access User-Agent deny all
5660 Or, to reproduce the old 'http_anonymizer paranoid' feature
5663 request_header_access Authorization allow all
5664 request_header_access Proxy-Authorization allow all
5665 request_header_access Cache-Control allow all
5666 request_header_access Content-Length allow all
5667 request_header_access Content-Type allow all
5668 request_header_access Date allow all
5669 request_header_access Host allow all
5670 request_header_access If-Modified-Since allow all
5671 request_header_access Pragma allow all
5672 request_header_access Accept allow all
5673 request_header_access Accept-Charset allow all
5674 request_header_access Accept-Encoding allow all
5675 request_header_access Accept-Language allow all
5676 request_header_access Connection allow all
5677 request_header_access All deny all
5679 HTTP reply headers are controlled with the reply_header_access directive.
5681 By default, all headers are allowed (no anonymizing is performed).
5684 NAME: reply_header_access
5685 IFDEF: USE_HTTP_VIOLATIONS
5686 TYPE: http_header_access
5687 LOC: Config.reply_header_access
5689 DEFAULT_DOC: No limits.
5691 Usage: reply_header_access header_name allow|deny [!]aclname ...
5693 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5694 this feature could make you liable for problems which it
5697 This option only applies to reply headers, i.e., from the
5698 server to the client.
5700 This is the same as request_header_access, but in the other
5701 direction. Please see request_header_access for detailed
5704 For example, to achieve the same behavior as the old
5705 'http_anonymizer standard' option, you should use:
5707 reply_header_access Server deny all
5708 reply_header_access WWW-Authenticate deny all
5709 reply_header_access Link deny all
5711 Or, to reproduce the old 'http_anonymizer paranoid' feature
5714 reply_header_access Allow allow all
5715 reply_header_access WWW-Authenticate allow all
5716 reply_header_access Proxy-Authenticate allow all
5717 reply_header_access Cache-Control allow all
5718 reply_header_access Content-Encoding allow all
5719 reply_header_access Content-Length allow all
5720 reply_header_access Content-Type allow all
5721 reply_header_access Date allow all
5722 reply_header_access Expires allow all
5723 reply_header_access Last-Modified allow all
5724 reply_header_access Location allow all
5725 reply_header_access Pragma allow all
5726 reply_header_access Content-Language allow all
5727 reply_header_access Retry-After allow all
5728 reply_header_access Title allow all
5729 reply_header_access Content-Disposition allow all
5730 reply_header_access Connection allow all
5731 reply_header_access All deny all
5733 HTTP request headers are controlled with the request_header_access directive.
5735 By default, all headers are allowed (no anonymizing is
5739 NAME: request_header_replace header_replace
5740 IFDEF: USE_HTTP_VIOLATIONS
5741 TYPE: http_header_replace
5742 LOC: Config.request_header_access
5745 Usage: request_header_replace header_name message
5746 Example: request_header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
5748 This option allows you to change the contents of headers
5749 denied with request_header_access above, by replacing them
5750 with some fixed string.
5752 This only applies to request headers, not reply headers.
5754 By default, headers are removed if denied.
5757 NAME: reply_header_replace
5758 IFDEF: USE_HTTP_VIOLATIONS
5759 TYPE: http_header_replace
5760 LOC: Config.reply_header_access
5763 Usage: reply_header_replace header_name message
5764 Example: reply_header_replace Server Foo/1.0
5766 This option allows you to change the contents of headers
5767 denied with reply_header_access above, by replacing them
5768 with some fixed string.
5770 This only applies to reply headers, not request headers.
5772 By default, headers are removed if denied.
5775 NAME: request_header_add
5776 TYPE: HeaderWithAclList
5777 LOC: Config.request_header_add
5780 Usage: request_header_add field-name field-value acl1 [acl2] ...
5781 Example: request_header_add X-Client-CA "CA=%ssl::>cert_issuer" all
5783 This option adds header fields to outgoing HTTP requests (i.e.,
5784 request headers sent by Squid to the next HTTP hop such as a
5785 cache peer or an origin server). The option has no effect during
5786 cache hit detection. The equivalent adaptation vectoring point
5787 in ICAP terminology is post-cache REQMOD.
5789 Field-name is a token specifying an HTTP header name. If a
5790 standard HTTP header name is used, Squid does not check whether
5791 the new header conflicts with any existing headers or violates
5792 HTTP rules. If the request to be modified already contains a
5793 field with the same name, the old field is preserved but the
5794 header field values are not merged.
5796 Field-value is either a token or a quoted string. If quoted
5797 string format is used, then the surrounding quotes are removed
5798 while escape sequences and %macros are processed.
5800 In theory, all of the logformat codes can be used as %macros.
5801 However, unlike logging (which happens at the very end of
5802 transaction lifetime), the transaction may not yet have enough
5803 information to expand a macro when the new header value is needed.
5804 And some information may already be available to Squid but not yet
5805 committed where the macro expansion code can access it (report
5806 such instances!). The macro will be expanded into a single dash
5807 ('-') in such cases. Not all macros have been tested.
5809 One or more Squid ACLs may be specified to restrict header
5810 injection to matching requests. As always in squid.conf, all
5811 ACLs in an option ACL list must be satisfied for the insertion
5812 to happen. The request_header_add option supports fast ACLs
5821 This option used to log custom information about the master
5822 transaction. For example, an admin may configure Squid to log
5823 which "user group" the transaction belongs to, where "user group"
5824 will be determined based on a set of ACLs and not [just]
5825 authentication information.
5826 Values of key/value pairs can be logged using %{key}note macros:
5828 note key value acl ...
5829 logformat myFormat ... %{key}note ...
5832 NAME: relaxed_header_parser
5833 COMMENT: on|off|warn
5835 LOC: Config.onoff.relaxed_header_parser
5838 In the default "on" setting Squid accepts certain forms
5839 of non-compliant HTTP messages where it is unambiguous
5840 what the sending application intended even if the message
5841 is not correctly formatted. The messages is then normalized
5842 to the correct form when forwarded by Squid.
5844 If set to "warn" then a warning will be emitted in cache.log
5845 each time such HTTP error is encountered.
5847 If set to "off" then such HTTP errors will cause the request
5848 or response to be rejected.
5851 NAME: collapsed_forwarding
5854 LOC: Config.onoff.collapsed_forwarding
5857 This option controls whether Squid is allowed to merge multiple
5858 potentially cachable requests for the same URI before Squid knows
5859 whether the response is going to be cachable.
5861 This feature is disabled by default: Enabling collapsed forwarding
5862 needlessly delays forwarding requests that look cachable (when they are
5863 collapsed) but then need to be forwarded individually anyway because
5864 they end up being for uncachable content. However, in some cases, such
5865 as accelleration of highly cachable content with periodic or groupped
5866 expiration times, the gains from collapsing [large volumes of
5867 simultenous refresh requests] outweigh losses from such delays.
5872 -----------------------------------------------------------------------------
5875 NAME: forward_timeout
5878 LOC: Config.Timeout.forward
5881 This parameter specifies how long Squid should at most attempt in
5882 finding a forwarding path for the request before giving up.
5885 NAME: connect_timeout
5888 LOC: Config.Timeout.connect
5891 This parameter specifies how long to wait for the TCP connect to
5892 the requested server or peer to complete before Squid should
5893 attempt to find another path where to forward the request.
5896 NAME: peer_connect_timeout
5899 LOC: Config.Timeout.peer_connect
5902 This parameter specifies how long to wait for a pending TCP
5903 connection to a peer cache. The default is 30 seconds. You
5904 may also set different timeout values for individual neighbors
5905 with the 'connect-timeout' option on a 'cache_peer' line.
5911 LOC: Config.Timeout.read
5914 The read_timeout is applied on server-side connections. After
5915 each successful read(), the timeout will be extended by this
5916 amount. If no data is read again after this amount of time,
5917 the request is aborted and logged with ERR_READ_TIMEOUT. The
5918 default is 15 minutes.
5924 LOC: Config.Timeout.write
5927 This timeout is tracked for all connections that have data
5928 available for writing and are waiting for the socket to become
5929 ready. After each successful write, the timeout is extended by
5930 the configured amount. If Squid has data to write but the
5931 connection is not ready for the configured duration, the
5932 transaction associated with the connection is terminated. The
5933 default is 15 minutes.
5936 NAME: request_timeout
5938 LOC: Config.Timeout.request
5941 How long to wait for complete HTTP request headers after initial
5942 connection establishment.
5945 NAME: client_idle_pconn_timeout persistent_request_timeout
5947 LOC: Config.Timeout.clientIdlePconn
5950 How long to wait for the next HTTP request on a persistent
5951 client connection after the previous request completes.
5954 NAME: client_lifetime
5957 LOC: Config.Timeout.lifetime
5960 The maximum amount of time a client (browser) is allowed to
5961 remain connected to the cache process. This protects the Cache
5962 from having a lot of sockets (and hence file descriptors) tied up
5963 in a CLOSE_WAIT state from remote clients that go away without
5964 properly shutting down (either because of a network failure or
5965 because of a poor client implementation). The default is one
5968 NOTE: The default value is intended to be much larger than any
5969 client would ever need to be connected to your cache. You
5970 should probably change client_lifetime only as a last resort.
5971 If you seem to have many client connections tying up
5972 filedescriptors, we recommend first tuning the read_timeout,
5973 request_timeout, persistent_request_timeout and quick_abort values.
5976 NAME: half_closed_clients
5978 LOC: Config.onoff.half_closed_clients
5981 Some clients may shutdown the sending side of their TCP
5982 connections, while leaving their receiving sides open. Sometimes,
5983 Squid can not tell the difference between a half-closed and a
5984 fully-closed TCP connection.
5986 By default, Squid will immediately close client connections when
5987 read(2) returns "no more data to read."
5989 Change this option to 'on' and Squid will keep open connections
5990 until a read(2) or write(2) on the socket returns an error.
5991 This may show some benefits for reverse proxies. But if not
5992 it is recommended to leave OFF.
5995 NAME: server_idle_pconn_timeout pconn_timeout
5997 LOC: Config.Timeout.serverIdlePconn
6000 Timeout for idle persistent connections to servers and other
6007 LOC: Ident::TheConfig.timeout
6010 Maximum time to wait for IDENT lookups to complete.
6012 If this is too high, and you enabled IDENT lookups from untrusted
6013 users, you might be susceptible to denial-of-service by having
6014 many ident requests going at once.
6017 NAME: shutdown_lifetime
6020 LOC: Config.shutdownLifetime
6023 When SIGTERM or SIGHUP is received, the cache is put into
6024 "shutdown pending" mode until all active sockets are closed.
6025 This value is the lifetime to set for all open descriptors
6026 during shutdown mode. Any active clients after this many
6027 seconds will receive a 'timeout' message.
6031 ADMINISTRATIVE PARAMETERS
6032 -----------------------------------------------------------------------------
6038 LOC: Config.adminEmail
6040 Email-address of local cache manager who will receive
6041 mail if the cache dies. The default is "webmaster".
6047 LOC: Config.EmailFrom
6049 From: email-address for mail sent when the cache dies.
6050 The default is to use 'squid@unique_hostname'.
6052 See also: unique_hostname directive.
6058 LOC: Config.EmailProgram
6060 Email program used to send mail if the cache dies.
6061 The default is "mail". The specified program must comply
6062 with the standard Unix mail syntax:
6063 mail-program recipient < mailfile
6065 Optional command line options can be specified.
6068 NAME: cache_effective_user
6070 DEFAULT: @DEFAULT_CACHE_EFFECTIVE_USER@
6071 LOC: Config.effectiveUser
6073 If you start Squid as root, it will change its effective/real
6074 UID/GID to the user specified below. The default is to change
6075 to UID of @DEFAULT_CACHE_EFFECTIVE_USER@.
6076 see also; cache_effective_group
6079 NAME: cache_effective_group
6082 DEFAULT_DOC: Use system group memberships of the cache_effective_user account
6083 LOC: Config.effectiveGroup
6085 Squid sets the GID to the effective user's default group ID
6086 (taken from the password file) and supplementary group list
6087 from the groups membership.
6089 If you want Squid to run with a specific GID regardless of
6090 the group memberships of the effective user then set this
6091 to the group (or GID) you want Squid to run as. When set
6092 all other group privileges of the effective user are ignored
6093 and only this GID is effective. If Squid is not started as
6094 root the user starting Squid MUST be member of the specified
6097 This option is not recommended by the Squid Team.
6098 Our preference is for administrators to configure a secure
6099 user account for squid with UID/GID matching system policies.
6102 NAME: httpd_suppress_version_string
6106 LOC: Config.onoff.httpd_suppress_version_string
6108 Suppress Squid version string info in HTTP headers and HTML error pages.
6111 NAME: visible_hostname
6113 LOC: Config.visibleHostname
6115 DEFAULT_DOC: Automatically detect the system host name
6117 If you want to present a special hostname in error messages, etc,
6118 define this. Otherwise, the return value of gethostname()
6119 will be used. If you have multiple caches in a cluster and
6120 get errors about IP-forwarding you must set them to have individual
6121 names with this setting.
6124 NAME: unique_hostname
6126 LOC: Config.uniqueHostname
6128 DEFAULT_DOC: Copy the value from visible_hostname
6130 If you want to have multiple machines with the same
6131 'visible_hostname' you must give each machine a different
6132 'unique_hostname' so forwarding loops can be detected.
6135 NAME: hostname_aliases
6137 LOC: Config.hostnameAliases
6140 A list of other DNS names your cache has.
6148 Minimum umask which should be enforced while the proxy
6149 is running, in addition to the umask set at startup.
6151 For a traditional octal representation of umasks, start
6156 OPTIONS FOR THE CACHE REGISTRATION SERVICE
6157 -----------------------------------------------------------------------------
6159 This section contains parameters for the (optional) cache
6160 announcement service. This service is provided to help
6161 cache administrators locate one another in order to join or
6162 create cache hierarchies.
6164 An 'announcement' message is sent (via UDP) to the registration
6165 service by Squid. By default, the announcement message is NOT
6166 SENT unless you enable it with 'announce_period' below.
6168 The announcement message includes your hostname, plus the
6169 following information from this configuration file:
6175 All current information is processed regularly and made
6176 available on the Web at http://www.ircache.net/Cache/Tracker/.
6179 NAME: announce_period
6181 LOC: Config.Announce.period
6183 DEFAULT_DOC: Announcement messages disabled.
6185 This is how frequently to send cache announcements.
6187 To enable announcing your cache, just set an announce period.
6190 announce_period 1 day
6195 DEFAULT: tracker.ircache.net
6196 LOC: Config.Announce.host
6198 Set the hostname where announce registration messages will be sent.
6200 See also announce_port and announce_file
6206 LOC: Config.Announce.file
6208 The contents of this file will be included in the announce
6209 registration messages.
6215 LOC: Config.Announce.port
6217 Set the port where announce registration messages will be sent.
6219 See also announce_host and announce_file
6223 HTTPD-ACCELERATOR OPTIONS
6224 -----------------------------------------------------------------------------
6227 NAME: httpd_accel_surrogate_id
6230 DEFAULT_DOC: visible_hostname is used if no specific ID is set.
6231 LOC: Config.Accel.surrogate_id
6233 Surrogates (http://www.esi.org/architecture_spec_1.0.html)
6234 need an identification token to allow control targeting. Because
6235 a farm of surrogates may all perform the same tasks, they may share
6236 an identification token.
6239 NAME: http_accel_surrogate_remote
6243 LOC: Config.onoff.surrogate_is_remote
6245 Remote surrogates (such as those in a CDN) honour the header
6246 "Surrogate-Control: no-store-remote".
6248 Set this to on to have squid behave as a remote surrogate.
6252 IFDEF: USE_SQUID_ESI
6253 COMMENT: libxml2|expat|custom
6255 LOC: ESIParser::Type
6258 ESI markup is not strictly XML compatible. The custom ESI parser
6259 will give higher performance, but cannot handle non ASCII character
6264 DELAY POOL PARAMETERS
6265 -----------------------------------------------------------------------------
6269 TYPE: delay_pool_count
6271 IFDEF: USE_DELAY_POOLS
6274 This represents the number of delay pools to be used. For example,
6275 if you have one class 2 delay pool and one class 3 delays pool, you
6276 have a total of 2 delay pools.
6278 See also delay_parameters, delay_class, delay_access for pool
6279 configuration details.
6283 TYPE: delay_pool_class
6285 IFDEF: USE_DELAY_POOLS
6288 This defines the class of each delay pool. There must be exactly one
6289 delay_class line for each delay pool. For example, to define two
6290 delay pools, one of class 2 and one of class 3, the settings above
6294 delay_pools 4 # 4 delay pools
6295 delay_class 1 2 # pool 1 is a class 2 pool
6296 delay_class 2 3 # pool 2 is a class 3 pool
6297 delay_class 3 4 # pool 3 is a class 4 pool
6298 delay_class 4 5 # pool 4 is a class 5 pool
6300 The delay pool classes are:
6302 class 1 Everything is limited by a single aggregate
6305 class 2 Everything is limited by a single aggregate
6306 bucket as well as an "individual" bucket chosen
6307 from bits 25 through 32 of the IPv4 address.
6309 class 3 Everything is limited by a single aggregate
6310 bucket as well as a "network" bucket chosen
6311 from bits 17 through 24 of the IP address and a
6312 "individual" bucket chosen from bits 17 through
6313 32 of the IPv4 address.
6315 class 4 Everything in a class 3 delay pool, with an
6316 additional limit on a per user basis. This
6317 only takes effect if the username is established
6318 in advance - by forcing authentication in your
6321 class 5 Requests are grouped according their tag (see
6322 external_acl's tag= reply).
6325 Each pool also requires a delay_parameters directive to configure the pool size
6326 and speed limits used whenever the pool is applied to a request. Along with
6327 a set of delay_access directives to determine when it is used.
6329 NOTE: If an IP address is a.b.c.d
6330 -> bits 25 through 32 are "d"
6331 -> bits 17 through 24 are "c"
6332 -> bits 17 through 32 are "c * 256 + d"
6334 NOTE-2: Due to the use of bitmasks in class 2,3,4 pools they only apply to
6335 IPv4 traffic. Class 1 and 5 pools may be used with IPv6 traffic.
6337 This clause only supports fast acl types.
6338 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6340 See also delay_parameters and delay_access.
6344 TYPE: delay_pool_access
6346 DEFAULT_DOC: Deny using the pool, unless allow rules exist in squid.conf for the pool.
6347 IFDEF: USE_DELAY_POOLS
6350 This is used to determine which delay pool a request falls into.
6352 delay_access is sorted per pool and the matching starts with pool 1,
6353 then pool 2, ..., and finally pool N. The first delay pool where the
6354 request is allowed is selected for the request. If it does not allow
6355 the request to any pool then the request is not delayed (default).
6357 For example, if you want some_big_clients in delay
6358 pool 1 and lotsa_little_clients in delay pool 2:
6360 delay_access 1 allow some_big_clients
6361 delay_access 1 deny all
6362 delay_access 2 allow lotsa_little_clients
6363 delay_access 2 deny all
6364 delay_access 3 allow authenticated_clients
6366 See also delay_parameters and delay_class.
6370 NAME: delay_parameters
6371 TYPE: delay_pool_rates
6373 IFDEF: USE_DELAY_POOLS
6376 This defines the parameters for a delay pool. Each delay pool has
6377 a number of "buckets" associated with it, as explained in the
6378 description of delay_class.
6380 For a class 1 delay pool, the syntax is:
6382 delay_parameters pool aggregate
6384 For a class 2 delay pool:
6386 delay_parameters pool aggregate individual
6388 For a class 3 delay pool:
6390 delay_parameters pool aggregate network individual
6392 For a class 4 delay pool:
6394 delay_parameters pool aggregate network individual user
6396 For a class 5 delay pool:
6398 delay_parameters pool tagrate
6400 The option variables are:
6402 pool a pool number - ie, a number between 1 and the
6403 number specified in delay_pools as used in
6406 aggregate the speed limit parameters for the aggregate bucket
6409 individual the speed limit parameters for the individual
6410 buckets (class 2, 3).
6412 network the speed limit parameters for the network buckets
6415 user the speed limit parameters for the user buckets
6418 tagrate the speed limit parameters for the tag buckets
6421 A pair of delay parameters is written restore/maximum, where restore is
6422 the number of bytes (not bits - modem and network speeds are usually
6423 quoted in bits) per second placed into the bucket, and maximum is the
6424 maximum number of bytes which can be in the bucket at any time.
6426 There must be one delay_parameters line for each delay pool.
6429 For example, if delay pool number 1 is a class 2 delay pool as in the
6430 above example, and is being used to strictly limit each host to 64Kbit/sec
6431 (plus overheads), with no overall limit, the line is:
6433 delay_parameters 1 -1/-1 8000/8000
6435 Note that 8 x 8000 KByte/sec -> 64Kbit/sec.
6437 Note that the figure -1 is used to represent "unlimited".
6440 And, if delay pool number 2 is a class 3 delay pool as in the above
6441 example, and you want to limit it to a total of 256Kbit/sec (strict limit)
6442 with each 8-bit network permitted 64Kbit/sec (strict limit) and each
6443 individual host permitted 4800bit/sec with a bucket maximum size of 64Kbits
6444 to permit a decent web page to be downloaded at a decent speed
6445 (if the network is not being limited due to overuse) but slow down
6446 large downloads more significantly:
6448 delay_parameters 2 32000/32000 8000/8000 600/8000
6450 Note that 8 x 32000 KByte/sec -> 256Kbit/sec.
6451 8 x 8000 KByte/sec -> 64Kbit/sec.
6452 8 x 600 Byte/sec -> 4800bit/sec.
6455 Finally, for a class 4 delay pool as in the example - each user will
6456 be limited to 128Kbits/sec no matter how many workstations they are logged into.:
6458 delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000
6461 See also delay_class and delay_access.
6465 NAME: delay_initial_bucket_level
6466 COMMENT: (percent, 0-100)
6469 IFDEF: USE_DELAY_POOLS
6470 LOC: Config.Delay.initial
6472 The initial bucket percentage is used to determine how much is put
6473 in each bucket when squid starts, is reconfigured, or first notices
6474 a host accessing it (in class 2 and class 3, individual hosts and
6475 networks only have buckets associated with them once they have been
6480 CLIENT DELAY POOL PARAMETERS
6481 -----------------------------------------------------------------------------
6484 NAME: client_delay_pools
6485 TYPE: client_delay_pool_count
6487 IFDEF: USE_DELAY_POOLS
6488 LOC: Config.ClientDelay
6490 This option specifies the number of client delay pools used. It must
6491 preceed other client_delay_* options.
6494 client_delay_pools 2
6496 See also client_delay_parameters and client_delay_access.
6499 NAME: client_delay_initial_bucket_level
6500 COMMENT: (percent, 0-no_limit)
6503 IFDEF: USE_DELAY_POOLS
6504 LOC: Config.ClientDelay.initial
6506 This option determines the initial bucket size as a percentage of
6507 max_bucket_size from client_delay_parameters. Buckets are created
6508 at the time of the "first" connection from the matching IP. Idle
6509 buckets are periodically deleted up.
6511 You can specify more than 100 percent but note that such "oversized"
6512 buckets are not refilled until their size goes down to max_bucket_size
6513 from client_delay_parameters.
6516 client_delay_initial_bucket_level 50
6519 NAME: client_delay_parameters
6520 TYPE: client_delay_pool_rates
6522 IFDEF: USE_DELAY_POOLS
6523 LOC: Config.ClientDelay
6526 This option configures client-side bandwidth limits using the
6529 client_delay_parameters pool speed_limit max_bucket_size
6531 pool is an integer ID used for client_delay_access matching.
6533 speed_limit is bytes added to the bucket per second.
6535 max_bucket_size is the maximum size of a bucket, enforced after any
6536 speed_limit additions.
6538 Please see the delay_parameters option for more information and
6542 client_delay_parameters 1 1024 2048
6543 client_delay_parameters 2 51200 16384
6545 See also client_delay_access.
6549 NAME: client_delay_access
6550 TYPE: client_delay_pool_access
6552 DEFAULT_DOC: Deny use of the pool, unless allow rules exist in squid.conf for the pool.
6553 IFDEF: USE_DELAY_POOLS
6554 LOC: Config.ClientDelay
6556 This option determines the client-side delay pool for the
6559 client_delay_access pool_ID allow|deny acl_name
6561 All client_delay_access options are checked in their pool ID
6562 order, starting with pool 1. The first checked pool with allowed
6563 request is selected for the request. If no ACL matches or there
6564 are no client_delay_access options, the request bandwidth is not
6567 The ACL-selected pool is then used to find the
6568 client_delay_parameters for the request. Client-side pools are
6569 not used to aggregate clients. Clients are always aggregated
6570 based on their source IP addresses (one bucket per source IP).
6572 This clause only supports fast acl types.
6573 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6574 Additionally, only the client TCP connection details are available.
6575 ACLs testing HTTP properties will not work.
6577 Please see delay_access for more examples.
6580 client_delay_access 1 allow low_rate_network
6581 client_delay_access 2 allow vips_network
6584 See also client_delay_parameters and client_delay_pools.
6588 WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS
6589 -----------------------------------------------------------------------------
6594 LOC: Config.Wccp.router
6596 DEFAULT_DOC: WCCP disabled.
6599 Use this option to define your WCCP ``home'' router for
6602 wccp_router supports a single WCCP(v1) router
6604 wccp2_router supports multiple WCCPv2 routers
6606 only one of the two may be used at the same time and defines
6607 which version of WCCP to use.
6611 TYPE: IpAddress_list
6612 LOC: Config.Wccp2.router
6614 DEFAULT_DOC: WCCPv2 disabled.
6617 Use this option to define your WCCP ``home'' router for
6620 wccp_router supports a single WCCP(v1) router
6622 wccp2_router supports multiple WCCPv2 routers
6624 only one of the two may be used at the same time and defines
6625 which version of WCCP to use.
6630 LOC: Config.Wccp.version
6634 This directive is only relevant if you need to set up WCCP(v1)
6635 to some very old and end-of-life Cisco routers. In all other
6636 setups it must be left unset or at the default setting.
6637 It defines an internal version in the WCCP(v1) protocol,
6638 with version 4 being the officially documented protocol.
6640 According to some users, Cisco IOS 11.2 and earlier only
6641 support WCCP version 3. If you're using that or an earlier
6642 version of IOS, you may need to change this value to 3, otherwise
6643 do not specify this parameter.
6646 NAME: wccp2_rebuild_wait
6648 LOC: Config.Wccp2.rebuildwait
6652 If this is enabled Squid will wait for the cache dir rebuild to finish
6653 before sending the first wccp2 HereIAm packet
6656 NAME: wccp2_forwarding_method
6658 LOC: Config.Wccp2.forwarding_method
6662 WCCP2 allows the setting of forwarding methods between the
6663 router/switch and the cache. Valid values are as follows:
6665 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
6666 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
6668 Currently (as of IOS 12.4) cisco routers only support GRE.
6669 Cisco switches only support the L2 redirect assignment method.
6672 NAME: wccp2_return_method
6674 LOC: Config.Wccp2.return_method
6678 WCCP2 allows the setting of return methods between the
6679 router/switch and the cache for packets that the cache
6680 decides not to handle. Valid values are as follows:
6682 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
6683 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
6685 Currently (as of IOS 12.4) cisco routers only support GRE.
6686 Cisco switches only support the L2 redirect assignment.
6688 If the "ip wccp redirect exclude in" command has been
6689 enabled on the cache interface, then it is still safe for
6690 the proxy server to use a l2 redirect method even if this
6691 option is set to GRE.
6694 NAME: wccp2_assignment_method
6696 LOC: Config.Wccp2.assignment_method
6700 WCCP2 allows the setting of methods to assign the WCCP hash
6701 Valid values are as follows:
6703 hash - Hash assignment
6704 mask - Mask assignment
6706 As a general rule, cisco routers support the hash assignment method
6707 and cisco switches support the mask assignment method.
6712 LOC: Config.Wccp2.info
6713 DEFAULT_IF_NONE: standard 0
6714 DEFAULT_DOC: Use the 'web-cache' standard service.
6717 WCCP2 allows for multiple traffic services. There are two
6718 types: "standard" and "dynamic". The standard type defines
6719 one service id - http (id 0). The dynamic service ids can be from
6720 51 to 255 inclusive. In order to use a dynamic service id
6721 one must define the type of traffic to be redirected; this is done
6722 using the wccp2_service_info option.
6724 The "standard" type does not require a wccp2_service_info option,
6725 just specifying the service id will suffice.
6727 MD5 service authentication can be enabled by adding
6728 "password=<password>" to the end of this service declaration.
6732 wccp2_service standard 0 # for the 'web-cache' standard service
6733 wccp2_service dynamic 80 # a dynamic service type which will be
6734 # fleshed out with subsequent options.
6735 wccp2_service standard 0 password=foo
6738 NAME: wccp2_service_info
6739 TYPE: wccp2_service_info
6740 LOC: Config.Wccp2.info
6744 Dynamic WCCPv2 services require further information to define the
6745 traffic you wish to have diverted.
6749 wccp2_service_info <id> protocol=<protocol> flags=<flag>,<flag>..
6750 priority=<priority> ports=<port>,<port>..
6752 The relevant WCCPv2 flags:
6753 + src_ip_hash, dst_ip_hash
6754 + source_port_hash, dst_port_hash
6755 + src_ip_alt_hash, dst_ip_alt_hash
6756 + src_port_alt_hash, dst_port_alt_hash
6759 The port list can be one to eight entries.
6763 wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source
6764 priority=240 ports=80
6766 Note: the service id must have been defined by a previous
6767 'wccp2_service dynamic <id>' entry.
6772 LOC: Config.Wccp2.weight
6776 Each cache server gets assigned a set of the destination
6777 hash proportional to their weight.
6782 LOC: Config.Wccp.address
6784 DEFAULT_DOC: Address selected by the operating system.
6787 Use this option if you require WCCPv2 to use a specific
6790 The default behavior is to not bind to any specific address.
6795 LOC: Config.Wccp2.address
6797 DEFAULT_DOC: Address selected by the operating system.
6800 Use this option if you require WCCP to use a specific
6803 The default behavior is to not bind to any specific address.
6807 PERSISTENT CONNECTION HANDLING
6808 -----------------------------------------------------------------------------
6810 Also see "pconn_timeout" in the TIMEOUTS section
6813 NAME: client_persistent_connections
6815 LOC: Config.onoff.client_pconns
6818 Persistent connection support for clients.
6819 Squid uses persistent connections (when allowed). You can use
6820 this option to disable persistent connections with clients.
6823 NAME: server_persistent_connections
6825 LOC: Config.onoff.server_pconns
6828 Persistent connection support for servers.
6829 Squid uses persistent connections (when allowed). You can use
6830 this option to disable persistent connections with servers.
6833 NAME: persistent_connection_after_error
6835 LOC: Config.onoff.error_pconns
6838 With this directive the use of persistent connections after
6839 HTTP errors can be disabled. Useful if you have clients
6840 who fail to handle errors on persistent connections proper.
6843 NAME: detect_broken_pconn
6845 LOC: Config.onoff.detect_broken_server_pconns
6848 Some servers have been found to incorrectly signal the use
6849 of HTTP/1.0 persistent connections even on replies not
6850 compatible, causing significant delays. This server problem
6851 has mostly been seen on redirects.
6853 By enabling this directive Squid attempts to detect such
6854 broken replies and automatically assume the reply is finished
6855 after 10 seconds timeout.
6859 CACHE DIGEST OPTIONS
6860 -----------------------------------------------------------------------------
6863 NAME: digest_generation
6864 IFDEF: USE_CACHE_DIGESTS
6866 LOC: Config.onoff.digest_generation
6869 This controls whether the server will generate a Cache Digest
6870 of its contents. By default, Cache Digest generation is
6871 enabled if Squid is compiled with --enable-cache-digests defined.
6874 NAME: digest_bits_per_entry
6875 IFDEF: USE_CACHE_DIGESTS
6877 LOC: Config.digest.bits_per_entry
6880 This is the number of bits of the server's Cache Digest which
6881 will be associated with the Digest entry for a given HTTP
6882 Method and URL (public key) combination. The default is 5.
6885 NAME: digest_rebuild_period
6886 IFDEF: USE_CACHE_DIGESTS
6889 LOC: Config.digest.rebuild_period
6892 This is the wait time between Cache Digest rebuilds.
6895 NAME: digest_rewrite_period
6897 IFDEF: USE_CACHE_DIGESTS
6899 LOC: Config.digest.rewrite_period
6902 This is the wait time between Cache Digest writes to
6906 NAME: digest_swapout_chunk_size
6909 IFDEF: USE_CACHE_DIGESTS
6910 LOC: Config.digest.swapout_chunk_size
6913 This is the number of bytes of the Cache Digest to write to
6914 disk at a time. It defaults to 4096 bytes (4KB), the Squid
6918 NAME: digest_rebuild_chunk_percentage
6919 COMMENT: (percent, 0-100)
6920 IFDEF: USE_CACHE_DIGESTS
6922 LOC: Config.digest.rebuild_chunk_percentage
6925 This is the percentage of the Cache Digest to be scanned at a
6926 time. By default it is set to 10% of the Cache Digest.
6931 -----------------------------------------------------------------------------
6936 LOC: Config.Port.snmp
6938 DEFAULT_DOC: SNMP disabled.
6941 The port number where Squid listens for SNMP requests. To enable
6942 SNMP support set this to a suitable port number. Port number
6943 3401 is often used for the Squid SNMP agent. By default it's
6944 set to "0" (disabled)
6952 LOC: Config.accessList.snmp
6954 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
6957 Allowing or denying access to the SNMP port.
6959 All access to the agent is denied by default.
6962 snmp_access allow|deny [!]aclname ...
6964 This clause only supports fast acl types.
6965 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6968 snmp_access allow snmppublic localhost
6969 snmp_access deny all
6972 NAME: snmp_incoming_address
6974 LOC: Config.Addrs.snmp_incoming
6976 DEFAULT_DOC: Accept SNMP packets from all machine interfaces.
6979 Just like 'udp_incoming_address', but for the SNMP port.
6981 snmp_incoming_address is used for the SNMP socket receiving
6982 messages from SNMP agents.
6984 The default snmp_incoming_address is to listen on all
6985 available network interfaces.
6988 NAME: snmp_outgoing_address
6990 LOC: Config.Addrs.snmp_outgoing
6992 DEFAULT_DOC: Use snmp_incoming_address or an address selected by the operating system.
6995 Just like 'udp_outgoing_address', but for the SNMP port.
6997 snmp_outgoing_address is used for SNMP packets returned to SNMP
7000 If snmp_outgoing_address is not set it will use the same socket
7001 as snmp_incoming_address. Only change this if you want to have
7002 SNMP replies sent using another address than where this Squid
7003 listens for SNMP queries.
7005 NOTE, snmp_incoming_address and snmp_outgoing_address can not have
7006 the same value since they both use the same port.
7011 -----------------------------------------------------------------------------
7014 NAME: icp_port udp_port
7017 DEFAULT_DOC: ICP disabled.
7018 LOC: Config.Port.icp
7020 The port number where Squid sends and receives ICP queries to
7021 and from neighbor caches. The standard UDP port for ICP is 3130.
7024 icp_port @DEFAULT_ICP_PORT@
7031 DEFAULT_DOC: HTCP disabled.
7032 LOC: Config.Port.htcp
7034 The port number where Squid sends and receives HTCP queries to
7035 and from neighbor caches. To turn it on you want to set it to
7042 NAME: log_icp_queries
7046 LOC: Config.onoff.log_udp
7048 If set, ICP queries are logged to access.log. You may wish
7049 do disable this if your ICP load is VERY high to speed things
7050 up or to simplify log analysis.
7053 NAME: udp_incoming_address
7055 LOC:Config.Addrs.udp_incoming
7057 DEFAULT_DOC: Accept packets from all machine interfaces.
7059 udp_incoming_address is used for UDP packets received from other
7062 The default behavior is to not bind to any specific address.
7064 Only change this if you want to have all UDP queries received on
7065 a specific interface/address.
7067 NOTE: udp_incoming_address is used by the ICP, HTCP, and DNS
7068 modules. Altering it will affect all of them in the same manner.
7070 see also; udp_outgoing_address
7072 NOTE, udp_incoming_address and udp_outgoing_address can not
7073 have the same value since they both use the same port.
7076 NAME: udp_outgoing_address
7078 LOC: Config.Addrs.udp_outgoing
7080 DEFAULT_DOC: Use udp_incoming_address or an address selected by the operating system.
7082 udp_outgoing_address is used for UDP packets sent out to other
7085 The default behavior is to not bind to any specific address.
7087 Instead it will use the same socket as udp_incoming_address.
7088 Only change this if you want to have UDP queries sent using another
7089 address than where this Squid listens for UDP queries from other
7092 NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS
7093 modules. Altering it will affect all of them in the same manner.
7095 see also; udp_incoming_address
7097 NOTE, udp_incoming_address and udp_outgoing_address can not
7098 have the same value since they both use the same port.
7105 LOC: Config.onoff.icp_hit_stale
7107 If you want to return ICP_HIT for stale cache objects, set this
7108 option to 'on'. If you have sibling relationships with caches
7109 in other administrative domains, this should be 'off'. If you only
7110 have sibling relationships with caches under your control,
7111 it is probably okay to set this to 'on'.
7112 If set to 'on', your siblings should use the option "allow-miss"
7113 on their cache_peer lines for connecting to you.
7116 NAME: minimum_direct_hops
7119 LOC: Config.minDirectHops
7121 If using the ICMP pinging stuff, do direct fetches for sites
7122 which are no more than this many hops away.
7125 NAME: minimum_direct_rtt
7129 LOC: Config.minDirectRtt
7131 If using the ICMP pinging stuff, do direct fetches for sites
7132 which are no more than this many rtt milliseconds away.
7138 LOC: Config.Netdb.low
7140 The low water mark for the ICMP measurement database.
7142 Note: high watermark controlled by netdb_high directive.
7144 These watermarks are counts, not percents. The defaults are
7145 (low) 900 and (high) 1000. When the high water mark is
7146 reached, database entries will be deleted until the low
7153 LOC: Config.Netdb.high
7155 The high water mark for the ICMP measurement database.
7157 Note: low watermark controlled by netdb_low directive.
7159 These watermarks are counts, not percents. The defaults are
7160 (low) 900 and (high) 1000. When the high water mark is
7161 reached, database entries will be deleted until the low
7165 NAME: netdb_ping_period
7167 LOC: Config.Netdb.period
7170 The minimum period for measuring a site. There will be at
7171 least this much delay between successive pings to the same
7172 network. The default is five minutes.
7179 LOC: Config.onoff.query_icmp
7181 If you want to ask your peers to include ICMP data in their ICP
7182 replies, enable this option.
7184 If your peer has configured Squid (during compilation) with
7185 '--enable-icmp' that peer will send ICMP pings to origin server
7186 sites of the URLs it receives. If you enable this option the
7187 ICP replies from that peer will include the ICMP data (if available).
7188 Then, when choosing a parent cache, Squid will choose the parent with
7189 the minimal RTT to the origin server. When this happens, the
7190 hierarchy field of the access.log will be
7191 "CLOSEST_PARENT_MISS". This option is off by default.
7194 NAME: test_reachability
7198 LOC: Config.onoff.test_reachability
7200 When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
7201 instead of ICP_MISS if the target host is NOT in the ICMP
7202 database, or has a zero RTT.
7205 NAME: icp_query_timeout
7208 DEFAULT_DOC: Dynamic detection.
7210 LOC: Config.Timeout.icp_query
7212 Normally Squid will automatically determine an optimal ICP
7213 query timeout value based on the round-trip-time of recent ICP
7214 queries. If you want to override the value determined by
7215 Squid, set this 'icp_query_timeout' to a non-zero value. This
7216 value is specified in MILLISECONDS, so, to use a 2-second
7217 timeout (the old default), you would write:
7219 icp_query_timeout 2000
7222 NAME: maximum_icp_query_timeout
7226 LOC: Config.Timeout.icp_query_max
7228 Normally the ICP query timeout is determined dynamically. But
7229 sometimes it can lead to very large values (say 5 seconds).
7230 Use this option to put an upper limit on the dynamic timeout
7231 value. Do NOT use this option to always use a fixed (instead
7232 of a dynamic) timeout value. To set a fixed timeout see the
7233 'icp_query_timeout' directive.
7236 NAME: minimum_icp_query_timeout
7240 LOC: Config.Timeout.icp_query_min
7242 Normally the ICP query timeout is determined dynamically. But
7243 sometimes it can lead to very small timeouts, even lower than
7244 the normal latency variance on your link due to traffic.
7245 Use this option to put an lower limit on the dynamic timeout
7246 value. Do NOT use this option to always use a fixed (instead
7247 of a dynamic) timeout value. To set a fixed timeout see the
7248 'icp_query_timeout' directive.
7251 NAME: background_ping_rate
7255 LOC: Config.backgroundPingRate
7257 Controls how often the ICP pings are sent to siblings that
7258 have background-ping set.
7262 MULTICAST ICP OPTIONS
7263 -----------------------------------------------------------------------------
7268 LOC: Config.mcast_group_list
7271 This tag specifies a list of multicast groups which your server
7272 should join to receive multicasted ICP queries.
7274 NOTE! Be very careful what you put here! Be sure you
7275 understand the difference between an ICP _query_ and an ICP
7276 _reply_. This option is to be set only if you want to RECEIVE
7277 multicast queries. Do NOT set this option to SEND multicast
7278 ICP (use cache_peer for that). ICP replies are always sent via
7279 unicast, so this option does not affect whether or not you will
7280 receive replies from multicast group members.
7282 You must be very careful to NOT use a multicast address which
7283 is already in use by another group of caches.
7285 If you are unsure about multicast, please read the Multicast
7286 chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
7288 Usage: mcast_groups 239.128.16.128 224.0.1.20
7290 By default, Squid doesn't listen on any multicast groups.
7293 NAME: mcast_miss_addr
7294 IFDEF: MULTICAST_MISS_STREAM
7296 LOC: Config.mcast_miss.addr
7298 DEFAULT_DOC: disabled.
7300 If you enable this option, every "cache miss" URL will
7301 be sent out on the specified multicast address.
7303 Do not enable this option unless you are are absolutely
7304 certain you understand what you are doing.
7307 NAME: mcast_miss_ttl
7308 IFDEF: MULTICAST_MISS_STREAM
7310 LOC: Config.mcast_miss.ttl
7313 This is the time-to-live value for packets multicasted
7314 when multicasting off cache miss URLs is enabled. By
7315 default this is set to 'site scope', i.e. 16.
7318 NAME: mcast_miss_port
7319 IFDEF: MULTICAST_MISS_STREAM
7321 LOC: Config.mcast_miss.port
7324 This is the port number to be used in conjunction with
7328 NAME: mcast_miss_encode_key
7329 IFDEF: MULTICAST_MISS_STREAM
7331 LOC: Config.mcast_miss.encode_key
7332 DEFAULT: XXXXXXXXXXXXXXXX
7334 The URLs that are sent in the multicast miss stream are
7335 encrypted. This is the encryption key.
7338 NAME: mcast_icp_query_timeout
7342 LOC: Config.Timeout.mcast_icp_query
7344 For multicast peers, Squid regularly sends out ICP "probes" to
7345 count how many other peers are listening on the given multicast
7346 address. This value specifies how long Squid should wait to
7347 count all the replies. The default is 2000 msec, or 2
7352 INTERNAL ICON OPTIONS
7353 -----------------------------------------------------------------------------
7356 NAME: icon_directory
7358 LOC: Config.icons.directory
7359 DEFAULT: @DEFAULT_ICON_DIR@
7361 Where the icons are stored. These are normally kept in
7365 NAME: global_internal_static
7367 LOC: Config.onoff.global_internal_static
7370 This directive controls is Squid should intercept all requests for
7371 /squid-internal-static/ no matter which host the URL is requesting
7372 (default on setting), or if nothing special should be done for
7373 such URLs (off setting). The purpose of this directive is to make
7374 icons etc work better in complex cache hierarchies where it may
7375 not always be possible for all corners in the cache mesh to reach
7376 the server generating a directory listing.
7379 NAME: short_icon_urls
7381 LOC: Config.icons.use_short_names
7384 If this is enabled Squid will use short URLs for icons.
7385 If disabled it will revert to the old behavior of including
7386 it's own name and port in the URL.
7388 If you run a complex cache hierarchy with a mix of Squid and
7389 other proxies you may need to disable this directive.
7394 -----------------------------------------------------------------------------
7397 NAME: error_directory
7399 LOC: Config.errorDirectory
7401 DEFAULT_DOC: Send error pages in the clients preferred language
7403 If you wish to create your own versions of the default
7404 error files to customize them to suit your company copy
7405 the error/template files to another directory and point
7408 WARNING: This option will disable multi-language support
7409 on error pages if used.
7411 The squid developers are interested in making squid available in
7412 a wide variety of languages. If you are making translations for a
7413 language that Squid does not currently provide please consider
7414 contributing your translation back to the project.
7415 http://wiki.squid-cache.org/Translations
7417 The squid developers working on translations are happy to supply drop-in
7418 translated error files in exchange for any new language contributions.
7421 NAME: error_default_language
7422 IFDEF: USE_ERR_LOCALES
7424 LOC: Config.errorDefaultLanguage
7426 DEFAULT_DOC: Generate English language pages.
7428 Set the default language which squid will send error pages in
7429 if no existing translation matches the clients language
7432 If unset (default) generic English will be used.
7434 The squid developers are interested in making squid available in
7435 a wide variety of languages. If you are interested in making
7436 translations for any language see the squid wiki for details.
7437 http://wiki.squid-cache.org/Translations
7440 NAME: error_log_languages
7441 IFDEF: USE_ERR_LOCALES
7443 LOC: Config.errorLogMissingLanguages
7446 Log to cache.log what languages users are attempting to
7447 auto-negotiate for translations.
7449 Successful negotiations are not logged. Only failures
7450 have meaning to indicate that Squid may need an upgrade
7451 of its error page translations.
7454 NAME: err_page_stylesheet
7456 LOC: Config.errorStylesheet
7457 DEFAULT: @DEFAULT_CONFIG_DIR@/errorpage.css
7459 CSS Stylesheet to pattern the display of Squid default error pages.
7461 For information on CSS see http://www.w3.org/Style/CSS/
7466 LOC: Config.errHtmlText
7469 HTML text to include in error messages. Make this a "mailto"
7470 URL to your admin address, or maybe just a link to your
7471 organizations Web page.
7473 To include this in your error messages, you must rewrite
7474 the error template files (found in the "errors" directory).
7475 Wherever you want the 'err_html_text' line to appear,
7476 insert a %L tag in the error template file.
7479 NAME: email_err_data
7482 LOC: Config.onoff.emailErrData
7485 If enabled, information about the occurred error will be
7486 included in the mailto links of the ERR pages (if %W is set)
7487 so that the email body contains the data.
7488 Syntax is <A HREF="mailto:%w%W">%w</A>
7493 LOC: Config.denyInfoList
7496 Usage: deny_info err_page_name acl
7497 or deny_info http://... acl
7498 or deny_info TCP_RESET acl
7500 This can be used to return a ERR_ page for requests which
7501 do not pass the 'http_access' rules. Squid remembers the last
7502 acl it evaluated in http_access, and if a 'deny_info' line exists
7503 for that ACL Squid returns a corresponding error page.
7505 The acl is typically the last acl on the http_access deny line which
7506 denied access. The exceptions to this rule are:
7507 - When Squid needs to request authentication credentials. It's then
7508 the first authentication related acl encountered
7509 - When none of the http_access lines matches. It's then the last
7510 acl processed on the last http_access line.
7511 - When the decision to deny access was made by an adaptation service,
7512 the acl name is the corresponding eCAP or ICAP service_name.
7514 NP: If providing your own custom error pages with error_directory
7515 you may also specify them by your custom file name:
7516 Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
7518 By defaut Squid will send "403 Forbidden". A different 4xx or 5xx
7519 may be specified by prefixing the file name with the code and a colon.
7520 e.g. 404:ERR_CUSTOM_ACCESS_DENIED
7522 Alternatively you can tell Squid to reset the TCP connection
7523 by specifying TCP_RESET.
7525 Or you can specify an error URL or URL pattern. The browsers will
7526 get redirected to the specified URL after formatting tags have
7527 been replaced. Redirect will be done with 302 or 307 according to
7528 HTTP/1.1 specs. A different 3xx code may be specified by prefixing
7529 the URL. e.g. 303:http://example.com/
7532 %a - username (if available. Password NOT included)
7535 %E - Error description
7537 %H - Request domain name
7538 %i - Client IP Address
7540 %o - Message result from external ACL helper
7541 %p - Request Port number
7542 %P - Request Protocol name
7543 %R - Request URL path
7544 %T - Timestamp in RFC 1123 format
7545 %U - Full canonical URL from client
7546 (HTTPS URLs terminate with *)
7547 %u - Full canonical URL from client
7548 %w - Admin email from squid.conf
7550 %% - Literal percent (%) code
7555 OPTIONS INFLUENCING REQUEST FORWARDING
7556 -----------------------------------------------------------------------------
7559 NAME: nonhierarchical_direct
7561 LOC: Config.onoff.nonhierarchical_direct
7564 By default, Squid will send any non-hierarchical requests
7565 (matching hierarchy_stoplist or not cacheable request type) direct
7568 When this is set to "off", Squid will prefer to send these
7569 requests to parents.
7571 Note that in most configurations, by turning this off you will only
7572 add latency to these request without any improvement in global hit
7575 This option only sets a preference. If the parent is unavailable a
7576 direct connection to the origin server may still be attempted. To
7577 completely prevent direct connections use never_direct.
7582 LOC: Config.onoff.prefer_direct
7585 Normally Squid tries to use parents for most requests. If you for some
7586 reason like it to first try going direct and only use a parent if
7587 going direct fails set this to on.
7589 By combining nonhierarchical_direct off and prefer_direct on you
7590 can set up Squid to use a parent as a backup path if going direct
7593 Note: If you want Squid to use parents for all requests see
7594 the never_direct directive. prefer_direct only modifies how Squid
7595 acts on cacheable requests.
7598 NAME: cache_miss_revalidate
7602 LOC: Config.onoff.cache_miss_revalidate
7604 Whether Squid on cache MISS will pass client revalidation requests
7605 to the server or tries to fetch new content for caching.
7606 This is useful while the cache is mostly empty to more quickly
7607 have the cache populated.
7609 When set to 'on' (default), Squid will pass all client If-* headers
7612 When set to 'off' and if the request is cacheable, Squid will
7613 remove the clients If-Modified-Since and If-None-Match headers from
7614 the request sent to the server.
7619 LOC: Config.accessList.AlwaysDirect
7621 DEFAULT_DOC: Prevent any cache_peer being used for this request.
7623 Usage: always_direct allow|deny [!]aclname ...
7625 Here you can use ACL elements to specify requests which should
7626 ALWAYS be forwarded by Squid to the origin servers without using
7627 any peers. For example, to always directly forward requests for
7628 local servers ignoring any parents or siblings you may have use
7631 acl local-servers dstdomain my.domain.net
7632 always_direct allow local-servers
7634 To always forward FTP requests directly, use
7637 always_direct allow FTP
7639 NOTE: There is a similar, but opposite option named
7640 'never_direct'. You need to be aware that "always_direct deny
7641 foo" is NOT the same thing as "never_direct allow foo". You
7642 may need to use a deny rule to exclude a more-specific case of
7643 some other rule. Example:
7645 acl local-external dstdomain external.foo.net
7646 acl local-servers dstdomain .foo.net
7647 always_direct deny local-external
7648 always_direct allow local-servers
7650 NOTE: If your goal is to make the client forward the request
7651 directly to the origin server bypassing Squid then this needs
7652 to be done in the client configuration. Squid configuration
7653 can only tell Squid how Squid should fetch the object.
7655 NOTE: This directive is not related to caching. The replies
7656 is cached as usual even if you use always_direct. To not cache
7657 the replies see the 'cache' directive.
7659 This clause supports both fast and slow acl types.
7660 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7665 LOC: Config.accessList.NeverDirect
7667 DEFAULT_DOC: Allow DNS results to be used for this request.
7669 Usage: never_direct allow|deny [!]aclname ...
7671 never_direct is the opposite of always_direct. Please read
7672 the description for always_direct if you have not already.
7674 With 'never_direct' you can use ACL elements to specify
7675 requests which should NEVER be forwarded directly to origin
7676 servers. For example, to force the use of a proxy for all
7677 requests, except those in your local domain use something like:
7679 acl local-servers dstdomain .foo.net
7680 never_direct deny local-servers
7681 never_direct allow all
7683 or if Squid is inside a firewall and there are local intranet
7684 servers inside the firewall use something like:
7686 acl local-intranet dstdomain .foo.net
7687 acl local-external dstdomain external.foo.net
7688 always_direct deny local-external
7689 always_direct allow local-intranet
7690 never_direct allow all
7692 This clause supports both fast and slow acl types.
7693 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7697 ADVANCED NETWORKING OPTIONS
7698 -----------------------------------------------------------------------------
7701 NAME: incoming_udp_average incoming_icp_average
7704 LOC: Config.comm_incoming.udp.average
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: incoming_tcp_average incoming_http_average
7714 LOC: Config.comm_incoming.tcp.average
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: incoming_dns_average
7724 LOC: Config.comm_incoming.dns.average
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!
7731 NAME: min_udp_poll_cnt min_icp_poll_cnt
7734 LOC: Config.comm_incoming.udp.min_poll
7736 Heavy voodoo here. I can't even believe you are reading this.
7737 Are you crazy? Don't even think about adjusting these unless
7738 you understand the algorithms in comm_select.c first!
7741 NAME: min_dns_poll_cnt
7744 LOC: Config.comm_incoming.dns.min_poll
7746 Heavy voodoo here. I can't even believe you are reading this.
7747 Are you crazy? Don't even think about adjusting these unless
7748 you understand the algorithms in comm_select.c first!
7751 NAME: min_tcp_poll_cnt min_http_poll_cnt
7754 LOC: Config.comm_incoming.tcp.min_poll
7756 Heavy voodoo here. I can't even believe you are reading this.
7757 Are you crazy? Don't even think about adjusting these unless
7758 you understand the algorithms in comm_select.c first!
7764 LOC: Config.accept_filter
7768 The name of an accept(2) filter to install on Squid's
7769 listen socket(s). This feature is perhaps specific to
7770 FreeBSD and requires support in the kernel.
7772 The 'httpready' filter delays delivering new connections
7773 to Squid until a full HTTP request has been received.
7774 See the accf_http(9) man page for details.
7776 The 'dataready' filter delays delivering new connections
7777 to Squid until there is some data to process.
7778 See the accf_dataready(9) man page for details.
7782 The 'data' filter delays delivering of new connections
7783 to Squid until there is some data to process by TCP_ACCEPT_DEFER.
7784 You may optionally specify a number of seconds to wait by
7785 'data=N' where N is the number of seconds. Defaults to 30
7786 if not specified. See the tcp(7) man page for details.
7789 accept_filter httpready
7794 NAME: client_ip_max_connections
7796 LOC: Config.client_ip_max_connections
7798 DEFAULT_DOC: No limit.
7800 Set an absolute limit on the number of connections a single
7801 client IP can use. Any more than this and Squid will begin to drop
7802 new connections from the client until it closes some links.
7804 Note that this is a global limit. It affects all HTTP, HTCP, Gopher and FTP
7805 connections from the client. For finer control use the ACL access controls.
7807 Requires client_db to be enabled (the default).
7809 WARNING: This may noticably slow down traffic received via external proxies
7810 or NAT devices and cause them to rebound error messages back to their clients.
7813 NAME: tcp_recv_bufsize
7817 DEFAULT_DOC: Use operating system TCP defaults.
7818 LOC: Config.tcpRcvBufsz
7820 Size of receive buffer to set for TCP sockets. Probably just
7821 as easy to change your kernel's default.
7822 Omit from squid.conf to use the default buffer size.
7827 -----------------------------------------------------------------------------
7834 LOC: Adaptation::Icap::TheConfig.onoff
7837 If you want to enable the ICAP module support, set this to on.
7840 NAME: icap_connect_timeout
7843 LOC: Adaptation::Icap::TheConfig.connect_timeout_raw
7846 This parameter specifies how long to wait for the TCP connect to
7847 the requested ICAP server to complete before giving up and either
7848 terminating the HTTP transaction or bypassing the failure.
7850 The default for optional services is peer_connect_timeout.
7851 The default for essential services is connect_timeout.
7852 If this option is explicitly set, its value applies to all services.
7855 NAME: icap_io_timeout
7859 DEFAULT_DOC: Use read_timeout.
7860 LOC: Adaptation::Icap::TheConfig.io_timeout_raw
7863 This parameter specifies how long to wait for an I/O activity on
7864 an established, active ICAP connection before giving up and
7865 either terminating the HTTP transaction or bypassing the
7869 NAME: icap_service_failure_limit
7870 COMMENT: limit [in memory-depth time-units]
7871 TYPE: icap_service_failure_limit
7873 LOC: Adaptation::Icap::TheConfig
7876 The limit specifies the number of failures that Squid tolerates
7877 when establishing a new TCP connection with an ICAP service. If
7878 the number of failures exceeds the limit, the ICAP service is
7879 not used for new ICAP requests until it is time to refresh its
7882 A negative value disables the limit. Without the limit, an ICAP
7883 service will not be considered down due to connectivity failures
7884 between ICAP OPTIONS requests.
7886 Squid forgets ICAP service failures older than the specified
7887 value of memory-depth. The memory fading algorithm
7888 is approximate because Squid does not remember individual
7889 errors but groups them instead, splitting the option
7890 value into ten time slots of equal length.
7892 When memory-depth is 0 and by default this option has no
7893 effect on service failure expiration.
7895 Squid always forgets failures when updating service settings
7896 using an ICAP OPTIONS transaction, regardless of this option
7900 # suspend service usage after 10 failures in 5 seconds:
7901 icap_service_failure_limit 10 in 5 seconds
7904 NAME: icap_service_revival_delay
7907 LOC: Adaptation::Icap::TheConfig.service_revival_delay
7910 The delay specifies the number of seconds to wait after an ICAP
7911 OPTIONS request failure before requesting the options again. The
7912 failed ICAP service is considered "down" until fresh OPTIONS are
7915 The actual delay cannot be smaller than the hardcoded minimum
7916 delay of 30 seconds.
7919 NAME: icap_preview_enable
7923 LOC: Adaptation::Icap::TheConfig.preview_enable
7926 The ICAP Preview feature allows the ICAP server to handle the
7927 HTTP message by looking only at the beginning of the message body
7928 or even without receiving the body at all. In some environments,
7929 previews greatly speedup ICAP processing.
7931 During an ICAP OPTIONS transaction, the server may tell Squid what
7932 HTTP messages should be previewed and how big the preview should be.
7933 Squid will not use Preview if the server did not request one.
7935 To disable ICAP Preview for all ICAP services, regardless of
7936 individual ICAP server OPTIONS responses, set this option to "off".
7938 icap_preview_enable off
7941 NAME: icap_preview_size
7944 LOC: Adaptation::Icap::TheConfig.preview_size
7946 DEFAULT_DOC: No preview sent.
7948 The default size of preview data to be sent to the ICAP server.
7949 This value might be overwritten on a per server basis by OPTIONS requests.
7952 NAME: icap_206_enable
7956 LOC: Adaptation::Icap::TheConfig.allow206_enable
7959 206 (Partial Content) responses is an ICAP extension that allows the
7960 ICAP agents to optionally combine adapted and original HTTP message
7961 content. The decision to combine is postponed until the end of the
7962 ICAP response. Squid supports Partial Content extension by default.
7964 Activation of the Partial Content extension is negotiated with each
7965 ICAP service during OPTIONS exchange. Most ICAP servers should handle
7966 negotation correctly even if they do not support the extension, but
7967 some might fail. To disable Partial Content support for all ICAP
7968 services and to avoid any negotiation, set this option to "off".
7974 NAME: icap_default_options_ttl
7977 LOC: Adaptation::Icap::TheConfig.default_options_ttl
7980 The default TTL value for ICAP OPTIONS responses that don't have
7981 an Options-TTL header.
7984 NAME: icap_persistent_connections
7988 LOC: Adaptation::Icap::TheConfig.reuse_connections
7991 Whether or not Squid should use persistent connections to
7995 NAME: adaptation_send_client_ip icap_send_client_ip
7997 IFDEF: USE_ADAPTATION
7999 LOC: Adaptation::Config::send_client_ip
8002 If enabled, Squid shares HTTP client IP information with adaptation
8003 services. For ICAP, Squid adds the X-Client-IP header to ICAP requests.
8004 For eCAP, Squid sets the libecap::metaClientIp transaction option.
8006 See also: adaptation_uses_indirect_client
8009 NAME: adaptation_send_username icap_send_client_username
8011 IFDEF: USE_ADAPTATION
8013 LOC: Adaptation::Config::send_username
8016 This sends authenticated HTTP client username (if available) to
8017 the adaptation service.
8019 For ICAP, the username value is encoded based on the
8020 icap_client_username_encode option and is sent using the header
8021 specified by the icap_client_username_header option.
8024 NAME: icap_client_username_header
8027 LOC: Adaptation::Icap::TheConfig.client_username_header
8028 DEFAULT: X-Client-Username
8030 ICAP request header name to use for adaptation_send_username.
8033 NAME: icap_client_username_encode
8037 LOC: Adaptation::Icap::TheConfig.client_username_encode
8040 Whether to base64 encode the authenticated client username.
8044 TYPE: icap_service_type
8046 LOC: Adaptation::Icap::TheConfig
8049 Defines a single ICAP service using the following format:
8051 icap_service id vectoring_point uri [option ...]
8054 an opaque identifier or name which is used to direct traffic to
8055 this specific service. Must be unique among all adaptation
8056 services in squid.conf.
8058 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
8059 This specifies at which point of transaction processing the
8060 ICAP service should be activated. *_postcache vectoring points
8061 are not yet supported.
8063 uri: icap://servername:port/servicepath
8064 ICAP server and service location.
8066 ICAP does not allow a single service to handle both REQMOD and RESPMOD
8067 transactions. Squid does not enforce that requirement. You can specify
8068 services with the same service_url and different vectoring_points. You
8069 can even specify multiple identical services as long as their
8070 service_names differ.
8072 To activate a service, use the adaptation_access directive. To group
8073 services, use adaptation_service_chain and adaptation_service_set.
8075 Service options are separated by white space. ICAP services support
8076 the following name=value options:
8079 If set to 'on' or '1', the ICAP service is treated as
8080 optional. If the service cannot be reached or malfunctions,
8081 Squid will try to ignore any errors and process the message as
8082 if the service was not enabled. No all ICAP errors can be
8083 bypassed. If set to 0, the ICAP service is treated as
8084 essential and all ICAP errors will result in an error page
8085 returned to the HTTP client.
8087 Bypass is off by default: services are treated as essential.
8090 If set to 'on' or '1', the ICAP service is allowed to
8091 dynamically change the current message adaptation plan by
8092 returning a chain of services to be used next. The services
8093 are specified using the X-Next-Services ICAP response header
8094 value, formatted as a comma-separated list of service names.
8095 Each named service should be configured in squid.conf. Other
8096 services are ignored. An empty X-Next-Services value results
8097 in an empty plan which ends the current adaptation.
8099 Dynamic adaptation plan may cross or cover multiple supported
8100 vectoring points in their natural processing order.
8102 Routing is not allowed by default: the ICAP X-Next-Services
8103 response header is ignored.
8106 Only has effect on split-stack systems. The default on those systems
8107 is to use IPv4-only connections. When set to 'on' this option will
8108 make Squid use IPv6-only connections to contact this ICAP service.
8110 on-overload=block|bypass|wait|force
8111 If the service Max-Connections limit has been reached, do
8112 one of the following for each new ICAP transaction:
8113 * block: send an HTTP error response to the client
8114 * bypass: ignore the "over-connected" ICAP service
8115 * wait: wait (in a FIFO queue) for an ICAP connection slot
8116 * force: proceed, ignoring the Max-Connections limit
8118 In SMP mode with N workers, each worker assumes the service
8119 connection limit is Max-Connections/N, even though not all
8120 workers may use a given service.
8122 The default value is "bypass" if service is bypassable,
8123 otherwise it is set to "wait".
8127 Use the given number as the Max-Connections limit, regardless
8128 of the Max-Connections value given by the service, if any.
8130 Older icap_service format without optional named parameters is
8131 deprecated but supported for backward compatibility.
8134 icap_service svcBlocker reqmod_precache icap://icap1.mydomain.net:1344/reqmod bypass=0
8135 icap_service svcLogger reqmod_precache icap://icap2.mydomain.net:1344/respmod routing=on
8139 TYPE: icap_class_type
8144 This deprecated option was documented to define an ICAP service
8145 chain, even though it actually defined a set of similar, redundant
8146 services, and the chains were not supported.
8148 To define a set of redundant services, please use the
8149 adaptation_service_set directive. For service chains, use
8150 adaptation_service_chain.
8154 TYPE: icap_access_type
8159 This option is deprecated. Please use adaptation_access, which
8160 has the same ICAP functionality, but comes with better
8161 documentation, and eCAP support.
8166 -----------------------------------------------------------------------------
8173 LOC: Adaptation::Ecap::TheConfig.onoff
8176 Controls whether eCAP support is enabled.
8180 TYPE: ecap_service_type
8182 LOC: Adaptation::Ecap::TheConfig
8185 Defines a single eCAP service
8187 ecap_service id vectoring_point uri [option ...]
8190 an opaque identifier or name which is used to direct traffic to
8191 this specific service. Must be unique among all adaptation
8192 services in squid.conf.
8194 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
8195 This specifies at which point of transaction processing the
8196 eCAP service should be activated. *_postcache vectoring points
8197 are not yet supported.
8199 uri: ecap://vendor/service_name?custom&cgi=style¶meters=optional
8200 Squid uses the eCAP service URI to match this configuration
8201 line with one of the dynamically loaded services. Each loaded
8202 eCAP service must have a unique URI. Obtain the right URI from
8203 the service provider.
8205 To activate a service, use the adaptation_access directive. To group
8206 services, use adaptation_service_chain and adaptation_service_set.
8208 Service options are separated by white space. eCAP services support
8209 the following name=value options:
8212 If set to 'on' or '1', the eCAP service is treated as optional.
8213 If the service cannot be reached or malfunctions, Squid will try
8214 to ignore any errors and process the message as if the service
8215 was not enabled. No all eCAP errors can be bypassed.
8216 If set to 'off' or '0', the eCAP service is treated as essential
8217 and all eCAP errors will result in an error page returned to the
8220 Bypass is off by default: services are treated as essential.
8223 If set to 'on' or '1', the eCAP service is allowed to
8224 dynamically change the current message adaptation plan by
8225 returning a chain of services to be used next.
8227 Dynamic adaptation plan may cross or cover multiple supported
8228 vectoring points in their natural processing order.
8230 Routing is not allowed by default.
8232 Older ecap_service format without optional named parameters is
8233 deprecated but supported for backward compatibility.
8237 ecap_service s1 reqmod_precache ecap://filters.R.us/leakDetector?on_error=block bypass=off
8238 ecap_service s2 respmod_precache ecap://filters.R.us/virusFilter config=/etc/vf.cfg bypass=on
8241 NAME: loadable_modules
8243 IFDEF: USE_LOADABLE_MODULES
8244 LOC: Config.loadable_module_names
8247 Instructs Squid to load the specified dynamic module(s) or activate
8248 preloaded module(s).
8250 loadable_modules @DEFAULT_PREFIX@/lib/MinimalAdapter.so
8254 MESSAGE ADAPTATION OPTIONS
8255 -----------------------------------------------------------------------------
8258 NAME: adaptation_service_set
8259 TYPE: adaptation_service_set_type
8260 IFDEF: USE_ADAPTATION
8265 Configures an ordered set of similar, redundant services. This is
8266 useful when hot standby or backup adaptation servers are available.
8268 adaptation_service_set set_name service_name1 service_name2 ...
8270 The named services are used in the set declaration order. The first
8271 applicable adaptation service from the set is used first. The next
8272 applicable service is tried if and only if the transaction with the
8273 previous service fails and the message waiting to be adapted is still
8276 When adaptation starts, broken services are ignored as if they were
8277 not a part of the set. A broken service is a down optional service.
8279 The services in a set must be attached to the same vectoring point
8280 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
8282 If all services in a set are optional then adaptation failures are
8283 bypassable. If all services in the set are essential, then a
8284 transaction failure with one service may still be retried using
8285 another service from the set, but when all services fail, the master
8286 transaction fails as well.
8288 A set may contain a mix of optional and essential services, but that
8289 is likely to lead to surprising results because broken services become
8290 ignored (see above), making previously bypassable failures fatal.
8291 Technically, it is the bypassability of the last failed service that
8294 See also: adaptation_access adaptation_service_chain
8297 adaptation_service_set svcBlocker urlFilterPrimary urlFilterBackup
8298 adaptation service_set svcLogger loggerLocal loggerRemote
8301 NAME: adaptation_service_chain
8302 TYPE: adaptation_service_chain_type
8303 IFDEF: USE_ADAPTATION
8308 Configures a list of complementary services that will be applied
8309 one-by-one, forming an adaptation chain or pipeline. This is useful
8310 when Squid must perform different adaptations on the same message.
8312 adaptation_service_chain chain_name service_name1 svc_name2 ...
8314 The named services are used in the chain declaration order. The first
8315 applicable adaptation service from the chain is used first. The next
8316 applicable service is applied to the successful adaptation results of
8317 the previous service in the chain.
8319 When adaptation starts, broken services are ignored as if they were
8320 not a part of the chain. A broken service is a down optional service.
8322 Request satisfaction terminates the adaptation chain because Squid
8323 does not currently allow declaration of RESPMOD services at the
8324 "reqmod_precache" vectoring point (see icap_service or ecap_service).
8326 The services in a chain must be attached to the same vectoring point
8327 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
8329 A chain may contain a mix of optional and essential services. If an
8330 essential adaptation fails (or the failure cannot be bypassed for
8331 other reasons), the master transaction fails. Otherwise, the failure
8332 is bypassed as if the failed adaptation service was not in the chain.
8334 See also: adaptation_access adaptation_service_set
8337 adaptation_service_chain svcRequest requestLogger urlFilter leakDetector
8340 NAME: adaptation_access
8341 TYPE: adaptation_access_type
8342 IFDEF: USE_ADAPTATION
8345 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
8347 Sends an HTTP transaction to an ICAP or eCAP adaptation service.
8349 adaptation_access service_name allow|deny [!]aclname...
8350 adaptation_access set_name allow|deny [!]aclname...
8352 At each supported vectoring point, the adaptation_access
8353 statements are processed in the order they appear in this
8354 configuration file. Statements pointing to the following services
8355 are ignored (i.e., skipped without checking their ACL):
8357 - services serving different vectoring points
8358 - "broken-but-bypassable" services
8359 - "up" services configured to ignore such transactions
8360 (e.g., based on the ICAP Transfer-Ignore header).
8362 When a set_name is used, all services in the set are checked
8363 using the same rules, to find the first applicable one. See
8364 adaptation_service_set for details.
8366 If an access list is checked and there is a match, the
8367 processing stops: For an "allow" rule, the corresponding
8368 adaptation service is used for the transaction. For a "deny"
8369 rule, no adaptation service is activated.
8371 It is currently not possible to apply more than one adaptation
8372 service at the same vectoring point to the same HTTP transaction.
8374 See also: icap_service and ecap_service
8377 adaptation_access service_1 allow all
8380 NAME: adaptation_service_iteration_limit
8382 IFDEF: USE_ADAPTATION
8383 LOC: Adaptation::Config::service_iteration_limit
8386 Limits the number of iterations allowed when applying adaptation
8387 services to a message. If your longest adaptation set or chain
8388 may have more than 16 services, increase the limit beyond its
8389 default value of 16. If detecting infinite iteration loops sooner
8390 is critical, make the iteration limit match the actual number
8391 of services in your longest adaptation set or chain.
8393 Infinite adaptation loops are most likely with routing services.
8395 See also: icap_service routing=1
8398 NAME: adaptation_masterx_shared_names
8400 IFDEF: USE_ADAPTATION
8401 LOC: Adaptation::Config::masterx_shared_name
8404 For each master transaction (i.e., the HTTP request and response
8405 sequence, including all related ICAP and eCAP exchanges), Squid
8406 maintains a table of metadata. The table entries are (name, value)
8407 pairs shared among eCAP and ICAP exchanges. The table is destroyed
8408 with the master transaction.
8410 This option specifies the table entry names that Squid must accept
8411 from and forward to the adaptation transactions.
8413 An ICAP REQMOD or RESPMOD transaction may set an entry in the
8414 shared table by returning an ICAP header field with a name
8415 specified in adaptation_masterx_shared_names.
8417 An eCAP REQMOD or RESPMOD transaction may set an entry in the
8418 shared table by implementing the libecap::visitEachOption() API
8419 to provide an option with a name specified in
8420 adaptation_masterx_shared_names.
8422 Squid will store and forward the set entry to subsequent adaptation
8423 transactions within the same master transaction scope.
8425 Only one shared entry name is supported at this time.
8428 # share authentication information among ICAP services
8429 adaptation_masterx_shared_names X-Subscriber-ID
8432 NAME: adaptation_meta
8434 IFDEF: USE_ADAPTATION
8435 LOC: Adaptation::Config::metaHeaders
8438 This option allows Squid administrator to add custom ICAP request
8439 headers or eCAP options to Squid ICAP requests or eCAP transactions.
8440 Use it to pass custom authentication tokens and other
8441 transaction-state related meta information to an ICAP/eCAP service.
8443 The addition of a meta header is ACL-driven:
8444 adaptation_meta name value [!]aclname ...
8446 Processing for a given header name stops after the first ACL list match.
8447 Thus, it is impossible to add two headers with the same name. If no ACL
8448 lists match for a given header name, no such header is added. For
8451 # do not debug transactions except for those that need debugging
8452 adaptation_meta X-Debug 1 needs_debugging
8454 # log all transactions except for those that must remain secret
8455 adaptation_meta X-Log 1 !keep_secret
8457 # mark transactions from users in the "G 1" group
8458 adaptation_meta X-Authenticated-Groups "G 1" authed_as_G1
8460 The "value" parameter may be a regular squid.conf token or a "double
8461 quoted string". Within the quoted string, use backslash (\) to escape
8462 any character, which is currently only useful for escaping backslashes
8463 and double quotes. For example,
8464 "this string has one backslash (\\) and two \"quotes\""
8466 Used adaptation_meta header values may be logged via %note
8467 logformat code. If multiple adaptation_meta headers with the same name
8468 are used during master transaction lifetime, the header values are
8469 logged in the order they were used and duplicate values are ignored
8470 (only the first repeated value will be logged).
8476 LOC: Adaptation::Icap::TheConfig.repeat
8477 DEFAULT_IF_NONE: deny all
8479 This ACL determines which retriable ICAP transactions are
8480 retried. Transactions that received a complete ICAP response
8481 and did not have to consume or produce HTTP bodies to receive
8482 that response are usually retriable.
8484 icap_retry allow|deny [!]aclname ...
8486 Squid automatically retries some ICAP I/O timeouts and errors
8487 due to persistent connection race conditions.
8489 See also: icap_retry_limit
8492 NAME: icap_retry_limit
8495 LOC: Adaptation::Icap::TheConfig.repeat_limit
8497 DEFAULT_DOC: No retries are allowed.
8499 Limits the number of retries allowed.
8501 Communication errors due to persistent connection race
8502 conditions are unavoidable, automatically retried, and do not
8503 count against this limit.
8505 See also: icap_retry
8511 -----------------------------------------------------------------------------
8514 NAME: check_hostnames
8517 LOC: Config.onoff.check_hostnames
8519 For security and stability reasons Squid can check
8520 hostnames for Internet standard RFC compliance. If you want
8521 Squid to perform these checks turn this directive on.
8524 NAME: allow_underscore
8527 LOC: Config.onoff.allow_underscore
8529 Underscore characters is not strictly allowed in Internet hostnames
8530 but nevertheless used by many sites. Set this to off if you want
8531 Squid to be strict about the standard.
8532 This check is performed only when check_hostnames is set to on.
8535 NAME: dns_retransmit_interval
8538 LOC: Config.Timeout.idns_retransmit
8540 Initial retransmit interval for DNS queries. The interval is
8541 doubled each time all configured DNS servers have been tried.
8547 LOC: Config.Timeout.idns_query
8549 DNS Query timeout. If no response is received to a DNS query
8550 within this time all DNS servers for the queried domain
8551 are assumed to be unavailable.
8554 NAME: dns_packet_max
8556 DEFAULT_DOC: EDNS disabled
8558 LOC: Config.dns.packet_max
8560 Maximum number of bytes packet size to advertise via EDNS.
8561 Set to "none" to disable EDNS large packet support.
8563 For legacy reasons DNS UDP replies will default to 512 bytes which
8564 is too small for many responses. EDNS provides a means for Squid to
8565 negotiate receiving larger responses back immediately without having
8566 to failover with repeat requests. Responses larger than this limit
8567 will retain the old behaviour of failover to TCP DNS.
8569 Squid has no real fixed limit internally, but allowing packet sizes
8570 over 1500 bytes requires network jumbogram support and is usually not
8573 WARNING: The RFC also indicates that some older resolvers will reply
8574 with failure of the whole request if the extension is added. Some
8575 resolvers have already been identified which will reply with mangled
8576 EDNS response on occasion. Usually in response to many-KB jumbogram
8577 sizes being advertised by Squid.
8578 Squid will currently treat these both as an unable-to-resolve domain
8579 even if it would be resolvable without EDNS.
8586 DEFAULT_DOC: Search for single-label domain names is disabled.
8587 LOC: Config.onoff.res_defnames
8589 Normally the RES_DEFNAMES resolver option is disabled
8590 (see res_init(3)). This prevents caches in a hierarchy
8591 from interpreting single-component hostnames locally. To allow
8592 Squid to handle single-component names, enable this option.
8595 NAME: dns_multicast_local
8599 DEFAULT_DOC: Search for .local and .arpa names is disabled.
8600 LOC: Config.onoff.dns_mdns
8602 When set to on, Squid sends multicast DNS lookups on the local
8603 network for domains ending in .local and .arpa.
8604 This enables local servers and devices to be contacted in an
8605 ad-hoc or zero-configuration network environment.
8608 NAME: dns_nameservers
8611 DEFAULT_DOC: Use operating system definitions
8612 LOC: Config.dns_nameservers
8614 Use this if you want to specify a list of DNS name servers
8615 (IP addresses) to use instead of those given in your
8616 /etc/resolv.conf file.
8618 On Windows platforms, if no value is specified here or in
8619 the /etc/resolv.conf file, the list of DNS name servers are
8620 taken from the Windows registry, both static and dynamic DHCP
8621 configurations are supported.
8623 Example: dns_nameservers 10.0.0.1 192.172.0.4
8628 DEFAULT: @DEFAULT_HOSTS@
8629 LOC: Config.etcHostsPath
8631 Location of the host-local IP name-address associations
8632 database. Most Operating Systems have such a file on different
8634 - Un*X & Linux: /etc/hosts
8635 - Windows NT/2000: %SystemRoot%\system32\drivers\etc\hosts
8636 (%SystemRoot% value install default is c:\winnt)
8637 - Windows XP/2003: %SystemRoot%\system32\drivers\etc\hosts
8638 (%SystemRoot% value install default is c:\windows)
8639 - Windows 9x/Me: %windir%\hosts
8640 (%windir% value is usually c:\windows)
8641 - Cygwin: /etc/hosts
8643 The file contains newline-separated definitions, in the
8644 form ip_address_in_dotted_form name [name ...] names are
8645 whitespace-separated. Lines beginning with an hash (#)
8646 character are comments.
8648 The file is checked at startup and upon configuration.
8649 If set to 'none', it won't be checked.
8650 If append_domain is used, that domain will be added to
8651 domain-local (i.e. not containing any dot character) host
8657 LOC: Config.appendDomain
8659 DEFAULT_DOC: Use operating system definitions
8661 Appends local domain name to hostnames without any dots in
8662 them. append_domain must begin with a period.
8664 Be warned there are now Internet names with no dots in
8665 them using only top-domain names, so setting this may
8666 cause some Internet sites to become unavailable.
8669 append_domain .yourdomain.com
8672 NAME: ignore_unknown_nameservers
8674 LOC: Config.onoff.ignore_unknown_nameservers
8677 By default Squid checks that DNS responses are received
8678 from the same IP addresses they are sent to. If they
8679 don't match, Squid ignores the response and writes a warning
8680 message to cache.log. You can allow responses from unknown
8681 nameservers by setting this option to 'off'.
8687 LOC: Config.dns.v4_first
8689 With the IPv6 Internet being as fast or faster than IPv4 Internet
8690 for most networks Squid prefers to contact websites over IPv6.
8692 This option reverses the order of preference to make Squid contact
8693 dual-stack websites over IPv4 first. Squid will still perform both
8694 IPv6 and IPv4 DNS lookups before connecting.
8697 This option will restrict the situations under which IPv6
8698 connectivity is used (and tested). Hiding network problems
8699 which would otherwise be detected and warned about.
8703 COMMENT: (number of entries)
8706 LOC: Config.ipcache.size
8708 Maximum number of DNS IP cache entries.
8715 LOC: Config.ipcache.low
8722 LOC: Config.ipcache.high
8724 The size, low-, and high-water marks for the IP cache.
8727 NAME: fqdncache_size
8728 COMMENT: (number of entries)
8731 LOC: Config.fqdncache.size
8733 Maximum number of FQDN cache entries.
8738 -----------------------------------------------------------------------------
8741 NAME: configuration_includes_quoted_values
8743 TYPE: configuration_includes_quoted_values
8745 LOC: ConfigParser::RecognizeQuotedValues
8747 If set, Squid will recognize each "quoted string" after a configuration
8748 directive as a single parameter. The quotes are stripped before the
8749 parameter value is interpreted or used.
8750 See "Values with spaces, quotes, and other special characters"
8751 section for more details.
8758 LOC: Config.onoff.mem_pools
8760 If set, Squid will keep pools of allocated (but unused) memory
8761 available for future use. If memory is a premium on your
8762 system and you believe your malloc library outperforms Squid
8763 routines, disable this.
8766 NAME: memory_pools_limit
8770 LOC: Config.MemPools.limit
8772 Used only with memory_pools on:
8773 memory_pools_limit 50 MB
8775 If set to a non-zero value, Squid will keep at most the specified
8776 limit of allocated (but unused) memory in memory pools. All free()
8777 requests that exceed this limit will be handled by your malloc
8778 library. Squid does not pre-allocate any memory, just safe-keeps
8779 objects that otherwise would be free()d. Thus, it is safe to set
8780 memory_pools_limit to a reasonably high value even if your
8781 configuration will use less memory.
8783 If set to none, Squid will keep all memory it can. That is, there
8784 will be no limit on the total amount of memory used for safe-keeping.
8786 To disable memory allocation optimization, do not set
8787 memory_pools_limit to 0 or none. Set memory_pools to "off" instead.
8789 An overhead for maintaining memory pools is not taken into account
8790 when the limit is checked. This overhead is close to four bytes per
8791 object kept. However, pools may actually _save_ memory because of
8792 reduced memory thrashing in your malloc library.
8796 COMMENT: on|off|transparent|truncate|delete
8799 LOC: opt_forwarded_for
8801 If set to "on", Squid will append your client's IP address
8802 in the HTTP requests it forwards. By default it looks like:
8804 X-Forwarded-For: 192.1.2.3
8806 If set to "off", it will appear as
8808 X-Forwarded-For: unknown
8810 If set to "transparent", Squid will not alter the
8811 X-Forwarded-For header in any way.
8813 If set to "delete", Squid will delete the entire
8814 X-Forwarded-For header.
8816 If set to "truncate", Squid will remove all existing
8817 X-Forwarded-For entries, and place the client IP as the sole entry.
8820 NAME: cachemgr_passwd
8821 TYPE: cachemgrpasswd
8823 DEFAULT_DOC: No password. Actions which require password are denied.
8824 LOC: Config.passwd_list
8826 Specify passwords for cachemgr operations.
8828 Usage: cachemgr_passwd password action action ...
8830 Some valid actions are (see cache manager menu for a full list):
8870 * Indicates actions which will not be performed without a
8871 valid password, others can be performed if not listed here.
8873 To disable an action, set the password to "disable".
8874 To allow performing an action without a password, set the
8877 Use the keyword "all" to set the same password for all actions.
8880 cachemgr_passwd secret shutdown
8881 cachemgr_passwd lesssssssecret info stats/objects
8882 cachemgr_passwd disable all
8889 LOC: Config.onoff.client_db
8891 If you want to disable collecting per-client statistics,
8892 turn off client_db here.
8895 NAME: refresh_all_ims
8899 LOC: Config.onoff.refresh_all_ims
8901 When you enable this option, squid will always check
8902 the origin server for an update when a client sends an
8903 If-Modified-Since request. Many browsers use IMS
8904 requests when the user requests a reload, and this
8905 ensures those clients receive the latest version.
8907 By default (off), squid may return a Not Modified response
8908 based on the age of the cached version.
8911 NAME: reload_into_ims
8912 IFDEF: USE_HTTP_VIOLATIONS
8916 LOC: Config.onoff.reload_into_ims
8918 When you enable this option, client no-cache or ``reload''
8919 requests will be changed to If-Modified-Since requests.
8920 Doing this VIOLATES the HTTP standard. Enabling this
8921 feature could make you liable for problems which it
8924 see also refresh_pattern for a more selective approach.
8927 NAME: connect_retries
8929 LOC: Config.connect_retries
8931 DEFAULT_DOC: Do not retry failed connections.
8933 This sets the maximum number of connection attempts made for each
8934 TCP connection. The connect_retries attempts must all still
8935 complete within the connection timeout period.
8937 The default is not to re-try if the first connection attempt fails.
8938 The (not recommended) maximum is 10 tries.
8940 A warning message will be generated if it is set to a too-high
8941 value and the configured value will be over-ridden.
8943 Note: These re-tries are in addition to forward_max_tries
8944 which limit how many different addresses may be tried to find
8948 NAME: retry_on_error
8950 LOC: Config.retry.onerror
8953 If set to ON Squid will automatically retry requests when
8954 receiving an error response with status 403 (Forbidden),
8955 500 (Internal Error), 501 or 503 (Service not available).
8956 Status 502 and 504 (Gateway errors) are always retried.
8958 This is mainly useful if you are in a complex cache hierarchy to
8959 work around access control errors.
8961 NOTE: This retry will attempt to find another working destination.
8962 Which is different from the server which just failed.
8965 NAME: as_whois_server
8967 LOC: Config.as_whois_server
8968 DEFAULT: whois.ra.net
8970 WHOIS server to query for AS numbers. NOTE: AS numbers are
8971 queried only when Squid starts up, not for every request.
8976 LOC: Config.onoff.offline
8979 Enable this option and Squid will never try to validate cached
8983 NAME: uri_whitespace
8984 TYPE: uri_whitespace
8985 LOC: Config.uri_whitespace
8988 What to do with requests that have whitespace characters in the
8991 strip: The whitespace characters are stripped out of the URL.
8992 This is the behavior recommended by RFC2396 and RFC3986
8993 for tolerant handling of generic URI.
8994 NOTE: This is one difference between generic URI and HTTP URLs.
8996 deny: The request is denied. The user receives an "Invalid
8998 This is the behaviour recommended by RFC2616 for safe
8999 handling of HTTP request URL.
9001 allow: The request is allowed and the URI is not changed. The
9002 whitespace characters remain in the URI. Note the
9003 whitespace is passed to redirector processes if they
9005 Note this may be considered a violation of RFC2616
9006 request parsing where whitespace is prohibited in the
9009 encode: The request is allowed and the whitespace characters are
9010 encoded according to RFC1738.
9012 chop: The request is allowed and the URI is chopped at the
9016 NOTE the current Squid implementation of encode and chop violates
9017 RFC2616 by not using a 301 redirect after altering the URL.
9022 LOC: Config.chroot_dir
9025 Specifies a directory where Squid should do a chroot() while
9026 initializing. This also causes Squid to fully drop root
9027 privileges after initializing. This means, for example, if you
9028 use a HTTP port less than 1024 and try to reconfigure, you may
9029 get an error saying that Squid can not open the port.
9032 NAME: balance_on_multiple_ip
9034 LOC: Config.onoff.balance_on_multiple_ip
9037 Modern IP resolvers in squid sort lookup results by preferred access.
9038 By default squid will use these IP in order and only rotates to
9039 the next listed when the most preffered fails.
9041 Some load balancing servers based on round robin DNS have been
9042 found not to preserve user session state across requests
9043 to different IP addresses.
9045 Enabling this directive Squid rotates IP's per request.
9048 NAME: pipeline_prefetch
9049 TYPE: pipelinePrefetch
9050 LOC: Config.pipeline_max_prefetch
9052 DEFAULT_DOC: Do not pre-parse pipelined requests.
9054 HTTP clients may send a pipeline of 1+N requests to Squid using a
9055 single connection, without waiting for Squid to respond to the first
9056 of those requests. This option limits the number of concurrent
9057 requests Squid will try to handle in parallel. If set to N, Squid
9058 will try to receive and process up to 1+N requests on the same
9059 connection concurrently.
9061 Defaults to 0 (off) for bandwidth management and access logging
9064 NOTE: pipelining requires persistent connections to clients.
9066 WARNING: pipelining breaks NTLM and Negotiate/Kerberos authentication.
9069 NAME: high_response_time_warning
9072 LOC: Config.warnings.high_rptm
9074 DEFAULT_DOC: disabled.
9076 If the one-minute median response time exceeds this value,
9077 Squid prints a WARNING with debug level 0 to get the
9078 administrators attention. The value is in milliseconds.
9081 NAME: high_page_fault_warning
9083 LOC: Config.warnings.high_pf
9085 DEFAULT_DOC: disabled.
9087 If the one-minute average page fault rate exceeds this
9088 value, Squid prints a WARNING with debug level 0 to get
9089 the administrators attention. The value is in page faults
9093 NAME: high_memory_warning
9095 LOC: Config.warnings.high_memory
9096 IFDEF: HAVE_MSTATS&&HAVE_GNUMALLOC_H
9098 DEFAULT_DOC: disabled.
9100 If the memory usage (as determined by gnumalloc, if available and used)
9101 exceeds this amount, Squid prints a WARNING with debug level 0 to get
9102 the administrators attention.
9104 # TODO: link high_memory_warning to mempools?
9106 NAME: sleep_after_fork
9107 COMMENT: (microseconds)
9109 LOC: Config.sleep_after_fork
9112 When this is set to a non-zero value, the main Squid process
9113 sleeps the specified number of microseconds after a fork()
9114 system call. This sleep may help the situation where your
9115 system reports fork() failures due to lack of (virtual)
9116 memory. Note, however, if you have a lot of child
9117 processes, these sleep delays will add up and your
9118 Squid will not service requests for some amount of time
9119 until all the child processes have been started.
9120 On Windows value less then 1000 (1 milliseconds) are
9124 NAME: windows_ipaddrchangemonitor
9125 IFDEF: _SQUID_WINDOWS_
9129 LOC: Config.onoff.WIN32_IpAddrChangeMonitor
9131 On Windows Squid by default will monitor IP address changes and will
9132 reconfigure itself after any detected event. This is very useful for
9133 proxies connected to internet with dial-up interfaces.
9134 In some cases (a Proxy server acting as VPN gateway is one) it could be
9135 desiderable to disable this behaviour setting this to 'off'.
9136 Note: after changing this, Squid service must be restarted.
9141 IFDEF: USE_SQUID_EUI
9143 LOC: Eui::TheConfig.euiLookup
9145 Whether to lookup the EUI or MAC address of a connected client.
9148 NAME: max_filedescriptors max_filedesc
9151 DEFAULT_DOC: Use operating system limits set by ulimit.
9152 LOC: Config.max_filedescriptors
9154 Reduce the maximum number of filedescriptors supported below
9155 the usual operating system defaults.
9157 Remove from squid.conf to inherit the current ulimit setting.
9159 Note: Changing this requires a restart of Squid. Also
9160 not all I/O types supports large values (eg on Windows).
9167 DEFAULT_DOC: SMP support disabled.
9169 Number of main Squid processes or "workers" to fork and maintain.
9170 0: "no daemon" mode, like running "squid -N ..."
9171 1: "no SMP" mode, start one main Squid process daemon (default)
9172 N: start N main Squid process daemons (i.e., SMP mode)
9174 In SMP mode, each worker does nearly all what a single Squid daemon
9175 does (e.g., listen on http_port and forward HTTP requests).
9178 NAME: cpu_affinity_map
9179 TYPE: CpuAffinityMap
9180 LOC: Config.cpuAffinityMap
9182 DEFAULT_DOC: Let operating system decide.
9184 Usage: cpu_affinity_map process_numbers=P1,P2,... cores=C1,C2,...
9186 Sets 1:1 mapping between Squid processes and CPU cores. For example,
9188 cpu_affinity_map process_numbers=1,2,3,4 cores=1,3,5,7
9190 affects processes 1 through 4 only and places them on the first
9191 four even cores, starting with core #1.
9193 CPU cores are numbered starting from 1. Requires support for
9194 sched_getaffinity(2) and sched_setaffinity(2) system calls.
9196 Multiple cpu_affinity_map options are merged.
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