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
68 Values with spaces, quotes, and other special characters
70 Squid supports directive parameters with spaces, quotes, and other
71 special characters. Surround such parameters with "double quotes". Use
72 the configuration_includes_quoted_values directive to enable or
75 Squid supports reading configuration option parameters from external
76 files using the syntax:
77 parameters("/path/filename")
79 acl whitelist dstdomain parameters("/etc/squid/whitelist.txt")
81 Conditional configuration
83 If-statements can be used to make configuration directives
87 ... regular configuration directives ...
89 ... regular configuration directives ...]
92 The else part is optional. The keywords "if", "else", and "endif"
93 must be typed on their own lines, as if they were regular
94 configuration directives.
96 NOTE: An else-if condition is not supported.
98 These individual conditions types are supported:
101 Always evaluates to true.
103 Always evaluates to false.
104 <integer> = <integer>
105 Equality comparison of two integer numbers.
110 The following SMP-related preprocessor macros can be used.
112 ${process_name} expands to the current Squid process "name"
113 (e.g., squid1, squid2, or cache1).
115 ${process_number} expands to the current Squid process
116 identifier, which is an integer number (e.g., 1, 2, 3) unique
117 across all Squid processes.
120 # options still not yet ported from 2.7 to 3.x
121 NAME: broken_vary_encoding
124 This option is not yet supported by Squid-3.
130 This option is not yet supported by Squid-3.
133 NAME: collapsed_forwarding
136 This option is not yet supported by Squid-3. see http://bugs.squid-cache.org/show_bug.cgi?id=3495
142 This option is not yet supported by Squid-3.
145 NAME: external_refresh_check
148 This option is not yet supported by Squid-3.
151 NAME: ignore_ims_on_miss
154 This option is not yet supported by Squid-3.
157 NAME: location_rewrite_program location_rewrite_access location_rewrite_children location_rewrite_concurrency
160 This option is not yet supported by Squid-3.
163 NAME: refresh_stale_hit
166 This option is not yet supported by Squid-3.
169 # no Options Removed in 3.3
171 # Options Removed in 3.2
172 NAME: ignore_expect_100
175 Remove this line. The HTTP/1.1 feature is now fully supported by default.
178 NAME: dns_v4_fallback
181 Remove this line. Squid performs a 'Happy Eyeballs' algorithm, the 'fallback' algorithm is no longer relevant.
187 Remove this line. Configure FTP page display using the CSS controls in errorpages.css instead.
190 NAME: maximum_single_addr_tries
193 Replaced by connect_retries. The behaviour has changed, please read the documentation before altering.
199 Remove this line. The feature is supported by default in storage types where update is implemented.
202 NAME: url_rewrite_concurrency
205 Remove this line. Set the 'concurrency=' option of url_rewrite_children instead.
208 # Options Removed in 3.1
212 Remove this line. DNS is no longer tested on startup.
215 NAME: extension_methods
218 Remove this line. All valid methods for HTTP are accepted by default.
221 # 2.7 Options Removed/Replaced in 3.2
226 # 2.7 Options Removed/Replaced in 3.1
234 Remove this line. HTTP/1.1 is supported by default.
237 NAME: upgrade_http0.9
240 Remove this line. ICY/1.0 streaming protocol is supported by default.
243 NAME: zph_local zph_mode zph_option zph_parent zph_sibling
246 Alter these entries. Use the qos_flows directive instead.
249 # Options Removed in 3.0
253 Since squid-3.0 replace with request_header_access or reply_header_access
254 depending on whether you wish to match client requests or server replies.
257 NAME: httpd_accel_no_pmtu_disc
260 Since squid-3.0 use the 'disable-pmtu-discovery' flag on http_port instead.
263 NAME: wais_relay_host
266 Replace this line with 'cache_peer' configuration.
269 NAME: wais_relay_port
272 Replace this line with 'cache_peer' configuration.
276 OPTIONS FOR AUTHENTICATION
277 -----------------------------------------------------------------------------
286 This is used to define parameters for the various authentication
287 schemes supported by Squid.
289 format: auth_param scheme parameter [setting]
291 The order in which authentication schemes are presented to the client is
292 dependent on the order the scheme first appears in config file. IE
293 has a bug (it's not RFC 2617 compliant) in that it will use the basic
294 scheme if basic is the first entry presented, even if more secure
295 schemes are presented. For now use the order in the recommended
296 settings section below. If other browsers have difficulties (don't
297 recognize the schemes offered even if you are using basic) either
298 put basic first, or disable the other schemes (by commenting out their
301 Once an authentication scheme is fully configured, it can only be
302 shutdown by shutting squid down and restarting. Changes can be made on
303 the fly and activated with a reconfigure. I.E. You can change to a
304 different helper, but not unconfigure the helper completely.
306 Please note that while this directive defines how Squid processes
307 authentication it does not automatically activate authentication.
308 To use authentication you must in addition make use of ACLs based
309 on login name in http_access (proxy_auth, proxy_auth_regex or
310 external with %LOGIN used in the format tag). The browser will be
311 challenged for authentication on the first such acl encountered
312 in http_access processing and will also be re-challenged for new
313 login credentials if the request is being denied by a proxy_auth
316 WARNING: authentication can't be used in a transparently intercepting
317 proxy as the client then thinks it is talking to an origin server and
318 not the proxy. This is a limitation of bending the TCP/IP protocol to
319 transparently intercepting port 80, not a limitation in Squid.
320 Ports flagged 'transparent', 'intercept', or 'tproxy' have
321 authentication disabled.
323 === Parameters for the basic scheme follow. ===
326 Specify the command for the external authenticator. Such a program
327 reads a line containing "username password" and replies with one of
334 the user does not exist.
337 An internal error occurred in the helper, preventing
338 a result being identified.
340 "ERR" and "BH" results may optionally be followed by message="..."
341 containing a description available as %m in the returned error page.
343 If you use an authenticator, make sure you have 1 acl of type
346 By default, the basic authentication scheme is not used unless a
347 program is specified.
349 If you want to use the traditional NCSA proxy authentication, set
350 this line to something like
352 auth_param basic program @DEFAULT_PREFIX@/libexec/basic_ncsa_auth @DEFAULT_PREFIX@/etc/passwd
355 HTTP uses iso-latin-1 as character set, while some authentication
356 backends such as LDAP expects UTF-8. If this is set to on Squid will
357 translate the HTTP iso-latin-1 charset to UTF-8 before sending the
358 username & password to the helper.
360 "children" numberofchildren [startup=N] [idle=N] [concurrency=N]
361 The maximum number of authenticator processes to spawn. If you start too few
362 Squid will have to wait for them to process a backlog of credential
363 verifications, slowing it down. When password verifications are
364 done via a (slow) network you are likely to need lots of
365 authenticator processes.
367 The startup= and idle= options permit some skew in the exact amount
368 run. A minimum of startup=N will begin during startup and reconfigure.
369 Squid will start more in groups of up to idle=N in an attempt to meet
370 traffic needs and to keep idle=N free above those traffic needs up to
373 The concurrency= option sets the number of concurrent requests the
374 helper can process. The default of 0 is used for helpers who only
375 supports one request at a time. Setting this to a number greater than
376 0 changes the protocol used to include a channel number first on the
377 request/response line, allowing multiple requests to be sent to the
378 same helper in parallel without waiting for the response.
379 Must not be set unless it's known the helper supports this.
381 auth_param basic children 20 startup=0 idle=1
384 Specifies the realm name which is to be reported to the
385 client for the basic proxy authentication scheme (part of
386 the text the user will see when prompted their username and
387 password). There is no default.
388 auth_param basic realm Squid proxy-caching web server
390 "credentialsttl" timetolive
391 Specifies how long squid assumes an externally validated
392 username:password pair is valid for - in other words how
393 often the helper program is called for that user. Set this
394 low to force revalidation with short lived passwords. Note
395 setting this high does not impact your susceptibility
396 to replay attacks unless you are using an one-time password
397 system (such as SecureID). If you are using such a system,
398 you will be vulnerable to replay attacks unless you also
399 use the max_user_ip ACL in an http_access rule.
401 "casesensitive" on|off
402 Specifies if usernames are case sensitive. Most user databases are
403 case insensitive allowing the same username to be spelled using both
404 lower and upper case letters, but some are case sensitive. This
405 makes a big difference for user_max_ip ACL processing and similar.
406 auth_param basic casesensitive off
408 === Parameters for the digest scheme follow ===
411 Specify the command for the external authenticator. Such
412 a program reads a line containing "username":"realm" and
413 replies with one of three results:
416 the user exists. The ha1= key is mandatory and
417 contains the appropriate H(A1) value, hex encoded.
418 See rfc 2616 for the definition of H(A1).
421 the user does not exist.
424 An internal error occurred in the helper, preventing
425 a result being identified.
427 "ERR" and "BH" results may optionally be followed by message="..."
428 containing a description available as %m in the returned error page.
430 By default, the digest authentication scheme is not used unless a
431 program is specified.
433 If you want to use a digest authenticator, set this line to
436 auth_param digest program @DEFAULT_PREFIX@/bin/digest_pw_auth @DEFAULT_PREFIX@/etc/digpass
439 HTTP uses iso-latin-1 as character set, while some authentication
440 backends such as LDAP expects UTF-8. If this is set to on Squid will
441 translate the HTTP iso-latin-1 charset to UTF-8 before sending the
442 username & password to the helper.
444 "children" numberofchildren [startup=N] [idle=N] [concurrency=N]
445 The maximum number of authenticator processes to spawn (default 5).
446 If you start too few Squid will have to wait for them to
447 process a backlog of H(A1) calculations, slowing it down.
448 When the H(A1) calculations are done via a (slow) network
449 you are likely to need lots of authenticator processes.
451 The startup= and idle= options permit some skew in the exact amount
452 run. A minimum of startup=N will begin during startup and reconfigure.
453 Squid will start more in groups of up to idle=N in an attempt to meet
454 traffic needs and to keep idle=N free above those traffic needs up to
457 The concurrency= option sets the number of concurrent requests the
458 helper can process. The default of 0 is used for helpers who only
459 supports one request at a time. Setting this to a number greater than
460 0 changes the protocol used to include a channel number first on the
461 request/response line, allowing multiple requests to be sent to the
462 same helper in parallel without waiting for the response.
463 Must not be set unless it's known the helper supports this.
465 auth_param digest children 20 startup=0 idle=1
468 Specifies the realm name which is to be reported to the
469 client for the digest proxy authentication scheme (part of
470 the text the user will see when prompted their username and
471 password). There is no default.
472 auth_param digest realm Squid proxy-caching web server
474 "nonce_garbage_interval" timeinterval
475 Specifies the interval that nonces that have been issued
476 to client_agent's are checked for validity.
478 "nonce_max_duration" timeinterval
479 Specifies the maximum length of time a given nonce will be
482 "nonce_max_count" number
483 Specifies the maximum number of times a given nonce can be
486 "nonce_strictness" on|off
487 Determines if squid requires strict increment-by-1 behavior
488 for nonce counts, or just incrementing (off - for use when
489 user agents generate nonce counts that occasionally miss 1
490 (ie, 1,2,4,6)). Default off.
492 "check_nonce_count" on|off
493 This directive if set to off can disable the nonce count check
494 completely to work around buggy digest qop implementations in
495 certain mainstream browser versions. Default on to check the
496 nonce count to protect from authentication replay attacks.
498 "post_workaround" on|off
499 This is a workaround to certain buggy browsers who sends
500 an incorrect request digest in POST requests when reusing
501 the same nonce as acquired earlier on a GET request.
503 === NTLM scheme options follow ===
506 Specify the command for the external NTLM authenticator.
507 Such a program reads exchanged NTLMSSP packets with
508 the browser via Squid until authentication is completed.
509 If you use an NTLM authenticator, make sure you have 1 acl
510 of type proxy_auth. By default, the NTLM authenticator program
513 auth_param ntlm program /usr/bin/ntlm_auth
515 "children" numberofchildren [startup=N] [idle=N]
516 The maximum number of authenticator processes to spawn (default 5).
517 If you start too few Squid will have to wait for them to
518 process a backlog of credential verifications, slowing it
519 down. When credential verifications are done via a (slow)
520 network you are likely to need lots of authenticator
523 The startup= and idle= options permit some skew in the exact amount
524 run. A minimum of startup=N will begin during startup and reconfigure.
525 Squid will start more in groups of up to idle=N in an attempt to meet
526 traffic needs and to keep idle=N free above those traffic needs up to
529 auth_param ntlm children 20 startup=0 idle=1
532 If you experience problems with PUT/POST requests when using the
533 Negotiate authentication scheme then you can try setting this to
534 off. This will cause Squid to forcibly close the connection on
535 the initial requests where the browser asks which schemes are
536 supported by the proxy.
538 auth_param ntlm keep_alive on
540 === Options for configuring the NEGOTIATE auth-scheme follow ===
543 Specify the command for the external Negotiate authenticator.
544 This protocol is used in Microsoft Active-Directory enabled setups with
545 the Microsoft Internet Explorer or Mozilla Firefox browsers.
546 Its main purpose is to exchange credentials with the Squid proxy
547 using the Kerberos mechanisms.
548 If you use a Negotiate authenticator, make sure you have at least
549 one acl of type proxy_auth active. By default, the negotiate
550 authenticator program is not used.
551 The only supported program for this role is the ntlm_auth
552 program distributed as part of Samba, version 4 or later.
554 auth_param negotiate program /usr/bin/ntlm_auth --helper-protocol=gss-spnego
556 "children" numberofchildren [startup=N] [idle=N]
557 The maximum number of authenticator processes to spawn (default 5).
558 If you start too few Squid will have to wait for them to
559 process a backlog of credential verifications, slowing it
560 down. When credential verifications are done via a (slow)
561 network you are likely to need lots of authenticator
564 The startup= and idle= options permit some skew in the exact amount
565 run. A minimum of startup=N will begin during startup and reconfigure.
566 Squid will start more in groups of up to idle=N in an attempt to meet
567 traffic needs and to keep idle=N free above those traffic needs up to
570 auth_param negotiate children 20 startup=0 idle=1
573 If you experience problems with PUT/POST requests when using the
574 Negotiate authentication scheme then you can try setting this to
575 off. This will cause Squid to forcibly close the connection on
576 the initial requests where the browser asks which schemes are
577 supported by the proxy.
579 auth_param negotiate keep_alive on
584 #Recommended minimum configuration per scheme:
585 #auth_param negotiate program <uncomment and complete this line to activate>
586 #auth_param negotiate children 20 startup=0 idle=1
587 #auth_param negotiate keep_alive on
589 #auth_param ntlm program <uncomment and complete this line to activate>
590 #auth_param ntlm children 20 startup=0 idle=1
591 #auth_param ntlm keep_alive on
593 #auth_param digest program <uncomment and complete this line>
594 #auth_param digest children 20 startup=0 idle=1
595 #auth_param digest realm Squid proxy-caching web server
596 #auth_param digest nonce_garbage_interval 5 minutes
597 #auth_param digest nonce_max_duration 30 minutes
598 #auth_param digest nonce_max_count 50
600 #auth_param basic program <uncomment and complete this line>
601 #auth_param basic children 5 startup=5 idle=1
602 #auth_param basic realm Squid proxy-caching web server
603 #auth_param basic credentialsttl 2 hours
606 NAME: authenticate_cache_garbage_interval
609 LOC: Config.authenticateGCInterval
611 The time period between garbage collection across the username cache.
612 This is a trade-off between memory utilization (long intervals - say
613 2 days) and CPU (short intervals - say 1 minute). Only change if you
617 NAME: authenticate_ttl
620 LOC: Config.authenticateTTL
622 The time a user & their credentials stay in the logged in
623 user cache since their last request. When the garbage
624 interval passes, all user credentials that have passed their
625 TTL are removed from memory.
628 NAME: authenticate_ip_ttl
630 LOC: Config.authenticateIpTTL
633 If you use proxy authentication and the 'max_user_ip' ACL,
634 this directive controls how long Squid remembers the IP
635 addresses associated with each user. Use a small value
636 (e.g., 60 seconds) if your users might change addresses
637 quickly, as is the case with dialup. You might be safe
638 using a larger value (e.g., 2 hours) in a corporate LAN
639 environment with relatively static address assignments.
644 -----------------------------------------------------------------------------
647 NAME: external_acl_type
648 TYPE: externalAclHelper
649 LOC: Config.externalAclHelperList
652 This option defines external acl classes using a helper program
653 to look up the status
655 external_acl_type name [options] FORMAT.. /path/to/helper [helper arguments..]
659 ttl=n TTL in seconds for cached results (defaults to 3600
662 TTL for cached negative lookups (default same
665 Maximum number of acl helper processes spawned to service
666 external acl lookups of this type. (default 20)
668 Minimum number of acl helper processes to spawn during
669 startup and reconfigure to service external acl lookups
670 of this type. (default 0)
672 Number of acl helper processes to keep ahead of traffic
673 loads. Squid will spawn this many at once whenever load
674 rises above the capabilities of existing processes.
675 Up to the value of children-max. (default 1)
676 concurrency=n concurrency level per process. Only used with helpers
677 capable of processing more than one query at a time.
678 cache=n limit the result cache size, default is unbounded.
679 grace=n Percentage remaining of TTL where a refresh of a
680 cached entry should be initiated without needing to
681 wait for a new reply. (default is for no grace period)
682 protocol=2.5 Compatibility mode for Squid-2.5 external acl helpers
683 ipv4 / ipv6 IP protocol used to communicate with this helper.
684 The default is to auto-detect IPv6 and use it when available.
686 FORMAT specifications
688 %LOGIN Authenticated user login name
689 %EXT_USER Username from previous external acl
690 %EXT_LOG Log details from previous external acl
691 %EXT_TAG Tag from previous external acl
692 %IDENT Ident user name
694 %SRCPORT Client source port
697 %PROTO Requested protocol
699 %PATH Requested URL path
700 %METHOD Request method
701 %MYADDR Squid interface address
702 %MYPORT Squid http_port number
703 %PATH Requested URL-path (including query-string if any)
704 %USER_CERT SSL User certificate in PEM format
705 %USER_CERTCHAIN SSL User certificate chain in PEM format
706 %USER_CERT_xx SSL User certificate subject attribute xx
707 %USER_CA_xx SSL User certificate issuer attribute xx
709 %>{Header} HTTP request header "Header"
711 HTTP request header "Hdr" list member "member"
713 HTTP request header list member using ; as
714 list separator. ; can be any non-alphanumeric
717 %<{Header} HTTP reply header "Header"
719 HTTP reply header "Hdr" list member "member"
721 HTTP reply header list member using ; as
722 list separator. ; can be any non-alphanumeric
725 %ACL The name of the ACL being tested.
726 %DATA The ACL arguments. If not used then any arguments
727 is automatically added at the end of the line
729 NOTE: this will encode the arguments as one token,
730 whereas the default will pass each separately.
732 %% The percent sign. Useful for helpers which need
733 an unchanging input format.
736 General request syntax:
738 [channel-ID] FORMAT-values [acl-values ...]
741 FORMAT-values consists of transaction details expanded with
742 whitespace separation per the config file FORMAT specification
743 using the FORMAT macros listed above.
745 acl-values consists of any string specified in the referencing
746 config 'acl ... external' line. see the "acl external" directive.
748 Request values sent to the helper are URL escaped to protect
749 each value in requests against whitespaces.
751 If using protocol=2.5 then the request sent to the helper is not
752 URL escaped to protect against whitespace.
754 NOTE: protocol=3.0 is deprecated as no longer necessary.
756 When using the concurrency= option the protocol is changed by
757 introducing a query channel tag in front of the request/response.
758 The query channel tag is a number between 0 and concurrency-1.
759 This value must be echoed back unchanged to Squid as the first part
760 of the response relating to its request.
763 The helper receives lines expanded per the above format specification
764 and for each input line returns 1 line starting with OK/ERR/BH result
765 code and optionally followed by additional keywords with more details.
768 General result syntax:
770 [channel-ID] result keyword=value ...
772 Result consists of one of the codes:
775 the ACL test produced a match.
778 the ACL test does not produce a match.
781 An internal error occurred in the helper, preventing
782 a result being identified.
784 The meaning of 'a match' is determined by your squid.conf
785 access control configuration. See the Squid wiki for details.
789 user= The users name (login)
791 password= The users password (for login= cache_peer option)
793 message= Message describing the reason for this response.
794 Available as %o in error pages.
795 Useful on (ERR and BH results).
797 tag= Apply a tag to a request. Only sets a tag once,
798 does not alter existing tags.
800 log= String to be logged in access.log. Available as
801 %ea in logformat specifications.
803 Any keywords may be sent on any response whether OK, ERR or BH.
805 All response keyword values need to be a single token with URL
806 escaping, or enclosed in double quotes (") and escaped using \ on
807 any double quotes or \ characters within the value. The wrapping
808 double quotes are removed before the value is interpreted by Squid.
809 \r and \n are also replace by CR and LF.
811 Some example key values:
815 user="J. \"Bob\" Smith"
822 DEFAULT: ssl::certHasExpired ssl_error X509_V_ERR_CERT_HAS_EXPIRED
823 DEFAULT: ssl::certNotYetValid ssl_error X509_V_ERR_CERT_NOT_YET_VALID
824 DEFAULT: ssl::certDomainMismatch ssl_error SQUID_X509_V_ERR_DOMAIN_MISMATCH
825 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
826 DEFAULT: ssl::certSelfSigned ssl_error X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT
829 DEFAULT: manager url_regex -i ^cache_object:// +i ^https?://[^/]+/squid-internal-mgr/
830 DEFAULT: localhost src 127.0.0.1/32 ::1
831 DEFAULT: to_localhost dst 127.0.0.0/8 0.0.0.0/32 ::1
832 DEFAULT_DOC: ACLs all, manager, localhost, and to_localhost are predefined.
834 Defining an Access List
836 Every access list definition must begin with an aclname and acltype,
837 followed by either type-specific arguments or a quoted filename that
840 acl aclname acltype argument ...
841 acl aclname acltype "file" ...
843 When using "file", the file should contain one item per line.
845 Some acl types supports options which changes their default behaviour.
846 The available options are:
848 -i,+i By default, regular expressions are CASE-SENSITIVE. To make them
849 case-insensitive, use the -i option. To return case-sensitive
850 use the +i option between patterns, or make a new ACL line
853 -n Disable lookups and address type conversions. If lookup or
854 conversion is required because the parameter type (IP or
855 domain name) does not match the message address type (domain
856 name or IP), then the ACL would immediately declare a mismatch
857 without any warnings or lookups.
859 -- Used to stop processing all options, in the case the first acl
860 value has '-' character as first character (for example the '-'
861 is a valid domain name)
863 Some acl types require suspending the current request in order
864 to access some external data source.
865 Those which do are marked with the tag [slow], those which
866 don't are marked as [fast].
867 See http://wiki.squid-cache.org/SquidFaq/SquidAcl
868 for further information
870 ***** ACL TYPES AVAILABLE *****
872 acl aclname src ip-address/mask ... # clients IP address [fast]
873 acl aclname src addr1-addr2/mask ... # range of addresses [fast]
874 acl aclname dst [-n] ip-address/mask ... # URL host's IP address [slow]
875 acl aclname localip ip-address/mask ... # IP address the client connected to [fast]
877 acl aclname arp mac-address ... (xx:xx:xx:xx:xx:xx notation)
878 # The arp ACL requires the special configure option --enable-arp-acl.
879 # Furthermore, the ARP ACL code is not portable to all operating systems.
880 # It works on Linux, Solaris, Windows, FreeBSD, and some
881 # other *BSD variants.
884 # NOTE: Squid can only determine the MAC address for clients that are on
885 # the same subnet. If the client is on a different subnet,
886 # then Squid cannot find out its MAC address.
888 acl aclname srcdomain .foo.com ...
889 # reverse lookup, from client IP [slow]
890 acl aclname dstdomain [-n] .foo.com ...
891 # Destination server from URL [fast]
892 acl aclname srcdom_regex [-i] \.foo\.com ...
893 # regex matching client name [slow]
894 acl aclname dstdom_regex [-n] [-i] \.foo\.com ...
895 # regex matching server [fast]
897 # For dstdomain and dstdom_regex a reverse lookup is tried if a IP
898 # based URL is used and no match is found. The name "none" is used
899 # if the reverse lookup fails.
901 acl aclname src_as number ...
902 acl aclname dst_as number ...
904 # Except for access control, AS numbers can be used for
905 # routing of requests to specific caches. Here's an
906 # example for routing all requests for AS#1241 and only
907 # those to mycache.mydomain.net:
908 # acl asexample dst_as 1241
909 # cache_peer_access mycache.mydomain.net allow asexample
910 # cache_peer_access mycache_mydomain.net deny all
912 acl aclname peername myPeer ...
914 # match against a named cache_peer entry
915 # set unique name= on cache_peer lines for reliable use.
917 acl aclname time [day-abbrevs] [h1:m1-h2:m2]
927 # h1:m1 must be less than h2:m2
929 acl aclname url_regex [-i] ^http:// ...
930 # regex matching on whole URL [fast]
931 acl aclname urllogin [-i] [^a-zA-Z0-9] ...
932 # regex matching on URL login field
933 acl aclname urlpath_regex [-i] \.gif$ ...
934 # regex matching on URL path [fast]
936 acl aclname port 80 70 21 0-1024... # destination TCP port [fast]
938 acl aclname localport 3128 ... # TCP port the client connected to [fast]
939 # NP: for interception mode this is usually '80'
941 acl aclname myportname 3128 ... # http(s)_port name [fast]
943 acl aclname proto HTTP FTP ... # request protocol [fast]
945 acl aclname method GET POST ... # HTTP request method [fast]
947 acl aclname http_status 200 301 500- 400-403 ...
948 # status code in reply [fast]
950 acl aclname browser [-i] regexp ...
951 # pattern match on User-Agent header (see also req_header below) [fast]
953 acl aclname referer_regex [-i] regexp ...
954 # pattern match on Referer header [fast]
955 # Referer is highly unreliable, so use with care
957 acl aclname ident username ...
958 acl aclname ident_regex [-i] pattern ...
959 # string match on ident output [slow]
960 # use REQUIRED to accept any non-null ident.
962 acl aclname proxy_auth [-i] username ...
963 acl aclname proxy_auth_regex [-i] pattern ...
964 # perform http authentication challenge to the client and match against
965 # supplied credentials [slow]
967 # takes a list of allowed usernames.
968 # use REQUIRED to accept any valid username.
970 # Will use proxy authentication in forward-proxy scenarios, and plain
971 # http authenticaiton in reverse-proxy scenarios
973 # NOTE: when a Proxy-Authentication header is sent but it is not
974 # needed during ACL checking the username is NOT logged
977 # NOTE: proxy_auth requires a EXTERNAL authentication program
978 # to check username/password combinations (see
979 # auth_param directive).
981 # NOTE: proxy_auth can't be used in a transparent/intercepting proxy
982 # as the browser needs to be configured for using a proxy in order
983 # to respond to proxy authentication.
985 acl aclname snmp_community string ...
986 # A community string to limit access to your SNMP Agent [fast]
989 # acl snmppublic snmp_community public
991 acl aclname maxconn number
992 # This will be matched when the client's IP address has
993 # more than <number> TCP connections established. [fast]
994 # NOTE: This only measures direct TCP links so X-Forwarded-For
995 # indirect clients are not counted.
997 acl aclname max_user_ip [-s] number
998 # This will be matched when the user attempts to log in from more
999 # than <number> different ip addresses. The authenticate_ip_ttl
1000 # parameter controls the timeout on the ip entries. [fast]
1001 # If -s is specified the limit is strict, denying browsing
1002 # from any further IP addresses until the ttl has expired. Without
1003 # -s Squid will just annoy the user by "randomly" denying requests.
1004 # (the counter is reset each time the limit is reached and a
1005 # request is denied)
1006 # NOTE: in acceleration mode or where there is mesh of child proxies,
1007 # clients may appear to come from multiple addresses if they are
1008 # going through proxy farms, so a limit of 1 may cause user problems.
1010 acl aclname random probability
1011 # Pseudo-randomly match requests. Based on the probability given.
1012 # Probability may be written as a decimal (0.333), fraction (1/3)
1013 # or ratio of matches:non-matches (3:5).
1015 acl aclname req_mime_type [-i] mime-type ...
1016 # regex match against the mime type of the request generated
1017 # by the client. Can be used to detect file upload or some
1018 # types HTTP tunneling requests [fast]
1019 # NOTE: This does NOT match the reply. You cannot use this
1020 # to match the returned file type.
1022 acl aclname req_header header-name [-i] any\.regex\.here
1023 # regex match against any of the known request headers. May be
1024 # thought of as a superset of "browser", "referer" and "mime-type"
1027 acl aclname rep_mime_type [-i] mime-type ...
1028 # regex match against the mime type of the reply received by
1029 # squid. Can be used to detect file download or some
1030 # types HTTP tunneling requests. [fast]
1031 # NOTE: This has no effect in http_access rules. It only has
1032 # effect in rules that affect the reply data stream such as
1033 # http_reply_access.
1035 acl aclname rep_header header-name [-i] any\.regex\.here
1036 # regex match against any of the known reply headers. May be
1037 # thought of as a superset of "browser", "referer" and "mime-type"
1040 acl aclname external class_name [arguments...]
1041 # external ACL lookup via a helper class defined by the
1042 # external_acl_type directive [slow]
1044 acl aclname user_cert attribute values...
1045 # match against attributes in a user SSL certificate
1046 # attribute is one of DN/C/O/CN/L/ST [fast]
1048 acl aclname ca_cert attribute values...
1049 # match against attributes a users issuing CA SSL certificate
1050 # attribute is one of DN/C/O/CN/L/ST [fast]
1052 acl aclname ext_user username ...
1053 acl aclname ext_user_regex [-i] pattern ...
1054 # string match on username returned by external acl helper [slow]
1055 # use REQUIRED to accept any non-null user name.
1057 acl aclname tag tagvalue ...
1058 # string match on tag returned by external acl helper [slow]
1060 acl aclname hier_code codename ...
1061 # string match against squid hierarchy code(s); [fast]
1062 # e.g., DIRECT, PARENT_HIT, NONE, etc.
1064 # NOTE: This has no effect in http_access rules. It only has
1065 # effect in rules that affect the reply data stream such as
1066 # http_reply_access.
1068 acl aclname note name [value ...]
1069 # match transaction annotation [fast]
1070 # Without values, matches any annotation with a given name.
1071 # With value(s), matches any annotation with a given name that
1072 # also has one of the given values.
1073 # Names and values are compared using a string equality test.
1074 # Annotation sources include note and adaptation_meta directives
1075 # as well as helper and eCAP responses.
1078 acl aclname ssl_error errorname
1079 # match against SSL certificate validation error [fast]
1081 # For valid error names see in @DEFAULT_ERROR_DIR@/templates/error-details.txt
1084 # The following can be used as shortcuts for certificate properties:
1085 # [ssl::]certHasExpired: the "not after" field is in the past
1086 # [ssl::]certNotYetValid: the "not before" field is in the future
1087 # [ssl::]certUntrusted: The certificate issuer is not to be trusted.
1088 # [ssl::]certSelfSigned: The certificate is self signed.
1089 # [ssl::]certDomainMismatch: The certificate CN domain does not
1090 # match the name the name of the host we are connecting to.
1092 # The ssl::certHasExpired, ssl::certNotYetValid, ssl::certDomainMismatch,
1093 # ssl::certUntrusted, and ssl::certSelfSigned can also be used as
1094 # predefined ACLs, just like the 'all' ACL.
1096 # NOTE: The ssl_error ACL is only supported with sslproxy_cert_error,
1097 # sslproxy_cert_sign, and sslproxy_cert_adapt options.
1099 acl aclname server_cert_fingerprint [-sha1] fingerprint
1100 # match against server SSL certificate fingerprint [fast]
1102 # The fingerprint is the digest of the DER encoded version
1103 # of the whole certificate. The user should use the form: XX:XX:...
1104 # Optional argument specifies the digest algorithm to use.
1105 # The SHA1 digest algorithm is the default and is currently
1106 # the only algorithm supported (-sha1).
1108 acl aclname any-of acl1 acl2 ...
1109 # match any one of the acls [fast or slow]
1110 # The first matching ACL stops further ACL evaluation.
1112 # ACLs from multiple any-of lines with the same name are ORed.
1113 # For example, A = (a1 or a2) or (a3 or a4) can be written as
1114 # acl A any-of a1 a2
1115 # acl A any-of a3 a4
1117 # This group ACL is fast if all evaluated ACLs in the group are fast
1118 # and slow otherwise.
1120 acl aclname all-of acl1 acl2 ...
1121 # match all of the acls [fast or slow]
1122 # The first mismatching ACL stops further ACL evaluation.
1124 # ACLs from multiple all-of lines with the same name are ORed.
1125 # For example, B = (b1 and b2) or (b3 and b4) can be written as
1126 # acl B all-of b1 b2
1127 # acl B all-of b3 b4
1129 # This group ACL is fast if all evaluated ACLs in the group are fast
1130 # and slow otherwise.
1133 acl macaddress arp 09:00:2b:23:45:67
1134 acl myexample dst_as 1241
1135 acl password proxy_auth REQUIRED
1136 acl fileupload req_mime_type -i ^multipart/form-data$
1137 acl javascript rep_mime_type -i ^application/x-javascript$
1141 # Recommended minimum configuration:
1144 # Example rule allowing access from your local networks.
1145 # Adapt to list your (internal) IP networks from where browsing
1147 acl localnet src 10.0.0.0/8 # RFC1918 possible internal network
1148 acl localnet src 172.16.0.0/12 # RFC1918 possible internal network
1149 acl localnet src 192.168.0.0/16 # RFC1918 possible internal network
1150 acl localnet src fc00::/7 # RFC 4193 local private network range
1151 acl localnet src fe80::/10 # RFC 4291 link-local (directly plugged) machines
1153 acl SSL_ports port 443
1154 acl Safe_ports port 80 # http
1155 acl Safe_ports port 21 # ftp
1156 acl Safe_ports port 443 # https
1157 acl Safe_ports port 70 # gopher
1158 acl Safe_ports port 210 # wais
1159 acl Safe_ports port 1025-65535 # unregistered ports
1160 acl Safe_ports port 280 # http-mgmt
1161 acl Safe_ports port 488 # gss-http
1162 acl Safe_ports port 591 # filemaker
1163 acl Safe_ports port 777 # multiling http
1164 acl CONNECT method CONNECT
1168 NAME: follow_x_forwarded_for
1170 IFDEF: FOLLOW_X_FORWARDED_FOR
1171 LOC: Config.accessList.followXFF
1172 DEFAULT_IF_NONE: deny all
1173 DEFAULT_DOC: X-Forwarded-For header will be ignored.
1175 Allowing or Denying the X-Forwarded-For header to be followed to
1176 find the original source of a request.
1178 Requests may pass through a chain of several other proxies
1179 before reaching us. The X-Forwarded-For header will contain a
1180 comma-separated list of the IP addresses in the chain, with the
1181 rightmost address being the most recent.
1183 If a request reaches us from a source that is allowed by this
1184 configuration item, then we consult the X-Forwarded-For header
1185 to see where that host received the request from. If the
1186 X-Forwarded-For header contains multiple addresses, we continue
1187 backtracking until we reach an address for which we are not allowed
1188 to follow the X-Forwarded-For header, or until we reach the first
1189 address in the list. For the purpose of ACL used in the
1190 follow_x_forwarded_for directive the src ACL type always matches
1191 the address we are testing and srcdomain matches its rDNS.
1193 The end result of this process is an IP address that we will
1194 refer to as the indirect client address. This address may
1195 be treated as the client address for access control, ICAP, delay
1196 pools and logging, depending on the acl_uses_indirect_client,
1197 icap_uses_indirect_client, delay_pool_uses_indirect_client,
1198 log_uses_indirect_client and tproxy_uses_indirect_client options.
1200 This clause only supports fast acl types.
1201 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1203 SECURITY CONSIDERATIONS:
1205 Any host for which we follow the X-Forwarded-For header
1206 can place incorrect information in the header, and Squid
1207 will use the incorrect information as if it were the
1208 source address of the request. This may enable remote
1209 hosts to bypass any access control restrictions that are
1210 based on the client's source addresses.
1214 acl localhost src 127.0.0.1
1215 acl my_other_proxy srcdomain .proxy.example.com
1216 follow_x_forwarded_for allow localhost
1217 follow_x_forwarded_for allow my_other_proxy
1220 NAME: acl_uses_indirect_client
1223 IFDEF: FOLLOW_X_FORWARDED_FOR
1225 LOC: Config.onoff.acl_uses_indirect_client
1227 Controls whether the indirect client address
1228 (see follow_x_forwarded_for) is used instead of the
1229 direct client address in acl matching.
1231 NOTE: maxconn ACL considers direct TCP links and indirect
1232 clients will always have zero. So no match.
1235 NAME: delay_pool_uses_indirect_client
1238 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_DELAY_POOLS
1240 LOC: Config.onoff.delay_pool_uses_indirect_client
1242 Controls whether the indirect client address
1243 (see follow_x_forwarded_for) is used instead of the
1244 direct client address in delay pools.
1247 NAME: log_uses_indirect_client
1250 IFDEF: FOLLOW_X_FORWARDED_FOR
1252 LOC: Config.onoff.log_uses_indirect_client
1254 Controls whether the indirect client address
1255 (see follow_x_forwarded_for) is used instead of the
1256 direct client address in the access log.
1259 NAME: tproxy_uses_indirect_client
1262 IFDEF: FOLLOW_X_FORWARDED_FOR&&LINUX_NETFILTER
1264 LOC: Config.onoff.tproxy_uses_indirect_client
1266 Controls whether the indirect client address
1267 (see follow_x_forwarded_for) is used instead of the
1268 direct client address when spoofing the outgoing client.
1270 This has no effect on requests arriving in non-tproxy
1273 SECURITY WARNING: Usage of this option is dangerous
1274 and should not be used trivially. Correct configuration
1275 of follow_x_forewarded_for with a limited set of trusted
1276 sources is required to prevent abuse of your proxy.
1279 NAME: spoof_client_ip
1281 LOC: Config.accessList.spoof_client_ip
1283 DEFAULT_DOC: Allow spoofing on all TPROXY traffic.
1285 Control client IP address spoofing of TPROXY traffic based on
1286 defined access lists.
1288 spoof_client_ip allow|deny [!]aclname ...
1290 If there are no "spoof_client_ip" lines present, the default
1291 is to "allow" spoofing of any suitable request.
1293 Note that the cache_peer "no-tproxy" option overrides this ACL.
1295 This clause supports fast acl types.
1296 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1301 LOC: Config.accessList.http
1302 DEFAULT_IF_NONE: deny all
1303 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1305 Allowing or Denying access based on defined access lists
1307 Access to the HTTP port:
1308 http_access allow|deny [!]aclname ...
1310 NOTE on default values:
1312 If there are no "access" lines present, the default is to deny
1315 If none of the "access" lines cause a match, the default is the
1316 opposite of the last line in the list. If the last line was
1317 deny, the default is allow. Conversely, if the last line
1318 is allow, the default will be deny. For these reasons, it is a
1319 good idea to have an "deny all" entry at the end of your access
1320 lists to avoid potential confusion.
1322 This clause supports both fast and slow acl types.
1323 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1328 # Recommended minimum Access Permission configuration:
1330 # Deny requests to certain unsafe ports
1331 http_access deny !Safe_ports
1333 # Deny CONNECT to other than secure SSL ports
1334 http_access deny CONNECT !SSL_ports
1336 # Only allow cachemgr access from localhost
1337 http_access allow localhost manager
1338 http_access deny manager
1340 # We strongly recommend the following be uncommented to protect innocent
1341 # web applications running on the proxy server who think the only
1342 # one who can access services on "localhost" is a local user
1343 #http_access deny to_localhost
1346 # INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS
1349 # Example rule allowing access from your local networks.
1350 # Adapt localnet in the ACL section to list your (internal) IP networks
1351 # from where browsing should be allowed
1352 http_access allow localnet
1353 http_access allow localhost
1355 # And finally deny all other access to this proxy
1356 http_access deny all
1360 NAME: adapted_http_access http_access2
1362 LOC: Config.accessList.adapted_http
1364 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1366 Allowing or Denying access based on defined access lists
1368 Essentially identical to http_access, but runs after redirectors
1369 and ICAP/eCAP adaptation. Allowing access control based on their
1372 If not set then only http_access is used.
1375 NAME: http_reply_access
1377 LOC: Config.accessList.reply
1379 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1381 Allow replies to client requests. This is complementary to http_access.
1383 http_reply_access allow|deny [!] aclname ...
1385 NOTE: if there are no access lines present, the default is to allow
1388 If none of the access lines cause a match the opposite of the
1389 last line will apply. Thus it is good practice to end the rules
1390 with an "allow all" or "deny all" entry.
1392 This clause supports both fast and slow acl types.
1393 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1398 LOC: Config.accessList.icp
1400 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1402 Allowing or Denying access to the ICP port based on defined
1405 icp_access allow|deny [!]aclname ...
1407 NOTE: The default if no icp_access lines are present is to
1408 deny all traffic. This default may cause problems with peers
1411 This clause only supports fast acl types.
1412 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1414 # Allow ICP queries from local networks only
1415 #icp_access allow localnet
1416 #icp_access deny all
1422 LOC: Config.accessList.htcp
1424 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1426 Allowing or Denying access to the HTCP port based on defined
1429 htcp_access allow|deny [!]aclname ...
1431 See also htcp_clr_access for details on access control for
1432 cache purge (CLR) HTCP messages.
1434 NOTE: The default if no htcp_access lines are present is to
1435 deny all traffic. This default may cause problems with peers
1436 using the htcp option.
1438 This clause only supports fast acl types.
1439 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1441 # Allow HTCP queries from local networks only
1442 #htcp_access allow localnet
1443 #htcp_access deny all
1446 NAME: htcp_clr_access
1449 LOC: Config.accessList.htcp_clr
1451 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1453 Allowing or Denying access to purge content using HTCP based
1454 on defined access lists.
1455 See htcp_access for details on general HTCP access control.
1457 htcp_clr_access allow|deny [!]aclname ...
1459 This clause only supports fast acl types.
1460 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1462 # Allow HTCP CLR requests from trusted peers
1463 acl htcp_clr_peer src 192.0.2.2 2001:DB8::2
1464 htcp_clr_access allow htcp_clr_peer
1465 htcp_clr_access deny all
1470 LOC: Config.accessList.miss
1472 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1474 Determins whether network access is permitted when satisfying a request.
1477 to force your neighbors to use you as a sibling instead of
1480 acl localclients src 192.0.2.0/24 2001:DB8::a:0/64
1481 miss_access deny !localclients
1482 miss_access allow all
1484 This means only your local clients are allowed to fetch relayed/MISS
1485 replies from the network and all other clients can only fetch cached
1488 The default for this setting allows all clients who passed the
1489 http_access rules to relay via this proxy.
1491 This clause only supports fast acl types.
1492 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1495 NAME: ident_lookup_access
1499 DEFAULT_DOC: Unless rules exist in squid.conf, IDENT is not fetched.
1500 LOC: Ident::TheConfig.identLookup
1502 A list of ACL elements which, if matched, cause an ident
1503 (RFC 931) lookup to be performed for this request. For
1504 example, you might choose to always perform ident lookups
1505 for your main multi-user Unix boxes, but not for your Macs
1506 and PCs. By default, ident lookups are not performed for
1509 To enable ident lookups for specific client addresses, you
1510 can follow this example:
1512 acl ident_aware_hosts src 198.168.1.0/24
1513 ident_lookup_access allow ident_aware_hosts
1514 ident_lookup_access deny all
1516 Only src type ACL checks are fully supported. A srcdomain
1517 ACL might work at times, but it will not always provide
1520 This clause only supports fast acl types.
1521 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1524 NAME: reply_body_max_size
1525 COMMENT: size [acl acl...]
1528 DEFAULT_DOC: No limit is applied.
1529 LOC: Config.ReplyBodySize
1531 This option specifies the maximum size of a reply body. It can be
1532 used to prevent users from downloading very large files, such as
1533 MP3's and movies. When the reply headers are received, the
1534 reply_body_max_size lines are processed, and the first line where
1535 all (if any) listed ACLs are true is used as the maximum body size
1538 This size is checked twice. First when we get the reply headers,
1539 we check the content-length value. If the content length value exists
1540 and is larger than the allowed size, the request is denied and the
1541 user receives an error message that says "the request or reply
1542 is too large." If there is no content-length, and the reply
1543 size exceeds this limit, the client's connection is just closed
1544 and they will receive a partial reply.
1546 WARNING: downstream caches probably can not detect a partial reply
1547 if there is no content-length header, so they will cache
1548 partial responses and give them out as hits. You should NOT
1549 use this option if you have downstream caches.
1551 WARNING: A maximum size smaller than the size of squid's error messages
1552 will cause an infinite loop and crash squid. Ensure that the smallest
1553 non-zero value you use is greater that the maximum header size plus
1554 the size of your largest error page.
1556 If you set this parameter none (the default), there will be
1559 Configuration Format is:
1560 reply_body_max_size SIZE UNITS [acl ...]
1562 reply_body_max_size 10 MB
1568 -----------------------------------------------------------------------------
1571 NAME: http_port ascii_port
1574 LOC: Config.Sockaddr.http
1576 Usage: port [mode] [options]
1577 hostname:port [mode] [options]
1578 1.2.3.4:port [mode] [options]
1580 The socket addresses where Squid will listen for HTTP client
1581 requests. You may specify multiple socket addresses.
1582 There are three forms: port alone, hostname with port, and
1583 IP address with port. If you specify a hostname or IP
1584 address, Squid binds the socket to that specific
1585 address. Most likely, you do not need to bind to a specific
1586 address, so you can use the port number alone.
1588 If you are running Squid in accelerator mode, you
1589 probably want to listen on port 80 also, or instead.
1591 The -a command line option may be used to specify additional
1592 port(s) where Squid listens for proxy request. Such ports will
1593 be plain proxy ports with no options.
1595 You may specify multiple socket addresses on multiple lines.
1599 intercept Support for IP-Layer interception of
1600 outgoing requests without browser settings.
1601 NP: disables authentication and IPv6 on the port.
1603 tproxy Support Linux TPROXY for spoofing outgoing
1604 connections using the client IP address.
1605 NP: disables authentication and maybe IPv6 on the port.
1607 accel Accelerator / reverse proxy mode
1609 ssl-bump For each CONNECT request allowed by ssl_bump ACLs,
1610 establish secure connection with the client and with
1611 the server, decrypt HTTPS messages as they pass through
1612 Squid, and treat them as unencrypted HTTP messages,
1613 becoming the man-in-the-middle.
1615 The ssl_bump option is required to fully enable
1616 bumping of CONNECT requests.
1618 Omitting the mode flag causes default forward proxy mode to be used.
1621 Accelerator Mode Options:
1623 defaultsite=domainname
1624 What to use for the Host: header if it is not present
1625 in a request. Determines what site (not origin server)
1626 accelerators should consider the default.
1628 no-vhost Disable using HTTP/1.1 Host header for virtual domain support.
1630 protocol= Protocol to reconstruct accelerated and intercepted
1631 requests with. Defaults to HTTP/1.1 for http_port and
1632 HTTPS/1.1 for https_port.
1633 When an unsupported value is configured Squid will
1634 produce a FATAL error.
1635 Values: HTTP or HTTP/1.1, HTTPS or HTTPS/1.1
1637 vport Virtual host port support. Using the http_port number
1638 instead of the port passed on Host: headers.
1640 vport=NN Virtual host port support. Using the specified port
1641 number instead of the port passed on Host: headers.
1644 Act as if this Squid is the origin server.
1645 This currently means generate new Date: and Expires:
1646 headers on HIT instead of adding Age:.
1648 ignore-cc Ignore request Cache-Control headers.
1650 WARNING: This option violates HTTP specifications if
1651 used in non-accelerator setups.
1653 allow-direct Allow direct forwarding in accelerator mode. Normally
1654 accelerated requests are denied direct forwarding as if
1655 never_direct was used.
1657 WARNING: this option opens accelerator mode to security
1658 vulnerabilities usually only affecting in interception
1659 mode. Make sure to protect forwarding with suitable
1660 http_access rules when using this.
1663 SSL Bump Mode Options:
1664 In addition to these options ssl-bump requires TLS/SSL options.
1666 generate-host-certificates[=<on|off>]
1667 Dynamically create SSL server certificates for the
1668 destination hosts of bumped CONNECT requests.When
1669 enabled, the cert and key options are used to sign
1670 generated certificates. Otherwise generated
1671 certificate will be selfsigned.
1672 If there is a CA certificate lifetime of the generated
1673 certificate equals lifetime of the CA certificate. If
1674 generated certificate is selfsigned lifetime is three
1676 This option is enabled by default when ssl-bump is used.
1677 See the ssl-bump option above for more information.
1679 dynamic_cert_mem_cache_size=SIZE
1680 Approximate total RAM size spent on cached generated
1681 certificates. If set to zero, caching is disabled. The
1682 default value is 4MB.
1686 cert= Path to SSL certificate (PEM format).
1688 key= Path to SSL private key file (PEM format)
1689 if not specified, the certificate file is
1690 assumed to be a combined certificate and
1693 version= The version of SSL/TLS supported
1694 1 automatic (default)
1701 cipher= Colon separated list of supported ciphers.
1702 NOTE: some ciphers such as EDH ciphers depend on
1703 additional settings. If those settings are
1704 omitted the ciphers may be silently ignored
1705 by the OpenSSL library.
1707 options= Various SSL implementation options. The most important
1709 NO_SSLv2 Disallow the use of SSLv2
1710 NO_SSLv3 Disallow the use of SSLv3
1711 NO_TLSv1 Disallow the use of TLSv1.0
1712 NO_TLSv1_1 Disallow the use of TLSv1.1
1713 NO_TLSv1_2 Disallow the use of TLSv1.2
1714 SINGLE_DH_USE Always create a new key when using
1715 temporary/ephemeral DH key exchanges
1716 ALL Enable various bug workarounds
1717 suggested as "harmless" by OpenSSL
1718 Be warned that this reduces SSL/TLS
1719 strength to some attacks.
1720 See OpenSSL SSL_CTX_set_options documentation for a
1721 complete list of options.
1723 clientca= File containing the list of CAs to use when
1724 requesting a client certificate.
1726 cafile= File containing additional CA certificates to
1727 use when verifying client certificates. If unset
1728 clientca will be used.
1730 capath= Directory containing additional CA certificates
1731 and CRL lists to use when verifying client certificates.
1733 crlfile= File of additional CRL lists to use when verifying
1734 the client certificate, in addition to CRLs stored in
1735 the capath. Implies VERIFY_CRL flag below.
1737 dhparams= File containing DH parameters for temporary/ephemeral
1738 DH key exchanges. See OpenSSL documentation for details
1739 on how to create this file.
1740 WARNING: EDH ciphers will be silently disabled if this
1743 sslflags= Various flags modifying the use of SSL:
1745 Don't request client certificates
1746 immediately, but wait until acl processing
1747 requires a certificate (not yet implemented).
1749 Don't use the default CA lists built in
1752 Don't allow for session reuse. Each connection
1753 will result in a new SSL session.
1755 Verify CRL lists when accepting client
1758 Verify CRL lists for all certificates in the
1759 client certificate chain.
1761 sslcontext= SSL session ID context identifier.
1765 connection-auth[=on|off]
1766 use connection-auth=off to tell Squid to prevent
1767 forwarding Microsoft connection oriented authentication
1768 (NTLM, Negotiate and Kerberos)
1770 disable-pmtu-discovery=
1771 Control Path-MTU discovery usage:
1772 off lets OS decide on what to do (default).
1773 transparent disable PMTU discovery when transparent
1775 always disable always PMTU discovery.
1777 In many setups of transparently intercepting proxies
1778 Path-MTU discovery can not work on traffic towards the
1779 clients. This is the case when the intercepting device
1780 does not fully track connections and fails to forward
1781 ICMP must fragment messages to the cache server. If you
1782 have such setup and experience that certain clients
1783 sporadically hang or never complete requests set
1784 disable-pmtu-discovery option to 'transparent'.
1786 name= Specifies a internal name for the port. Defaults to
1787 the port specification (port or addr:port)
1789 tcpkeepalive[=idle,interval,timeout]
1790 Enable TCP keepalive probes of idle connections.
1791 In seconds; idle is the initial time before TCP starts
1792 probing the connection, interval how often to probe, and
1793 timeout the time before giving up.
1795 If you run Squid on a dual-homed machine with an internal
1796 and an external interface we recommend you to specify the
1797 internal address:port in http_port. This way Squid will only be
1798 visible on the internal address.
1802 # Squid normally listens to port 3128
1803 http_port @DEFAULT_HTTP_PORT@
1811 LOC: Config.Sockaddr.https
1813 Usage: [ip:]port cert=certificate.pem [key=key.pem] [mode] [options...]
1815 The socket address where Squid will listen for client requests made
1816 over TLS or SSL connections. Commonly referred to as HTTPS.
1818 This is most useful for situations where you are running squid in
1819 accelerator mode and you want to do the SSL work at the accelerator level.
1821 You may specify multiple socket addresses on multiple lines,
1822 each with their own SSL certificate and/or options.
1826 accel Accelerator / reverse proxy mode
1828 intercept Support for IP-Layer interception of
1829 outgoing requests without browser settings.
1830 NP: disables authentication and IPv6 on the port.
1832 tproxy Support Linux TPROXY for spoofing outgoing
1833 connections using the client IP address.
1834 NP: disables authentication and maybe IPv6 on the port.
1836 ssl-bump For each intercepted connection allowed by ssl_bump
1837 ACLs, establish a secure connection with the client and with
1838 the server, decrypt HTTPS messages as they pass through
1839 Squid, and treat them as unencrypted HTTP messages,
1840 becoming the man-in-the-middle.
1842 An "ssl_bump server-first" match is required to
1843 fully enable bumping of intercepted SSL connections.
1845 Requires tproxy or intercept.
1847 Omitting the mode flag causes default forward proxy mode to be used.
1850 See http_port for a list of generic options
1855 cert= Path to SSL certificate (PEM format).
1857 key= Path to SSL private key file (PEM format)
1858 if not specified, the certificate file is
1859 assumed to be a combined certificate and
1862 version= The version of SSL/TLS supported
1863 1 automatic (default)
1868 cipher= Colon separated list of supported ciphers.
1870 options= Various SSL engine options. The most important
1872 NO_SSLv2 Disallow the use of SSLv2
1873 NO_SSLv3 Disallow the use of SSLv3
1874 NO_TLSv1 Disallow the use of TLSv1
1875 SINGLE_DH_USE Always create a new key when using
1876 temporary/ephemeral DH key exchanges
1877 See src/ssl_support.c or OpenSSL SSL_CTX_set_options
1878 documentation for a complete list of options.
1880 clientca= File containing the list of CAs to use when
1881 requesting a client certificate.
1883 cafile= File containing additional CA certificates to
1884 use when verifying client certificates. If unset
1885 clientca will be used.
1887 capath= Directory containing additional CA certificates
1888 and CRL lists to use when verifying client certificates.
1890 crlfile= File of additional CRL lists to use when verifying
1891 the client certificate, in addition to CRLs stored in
1892 the capath. Implies VERIFY_CRL flag below.
1894 dhparams= File containing DH parameters for temporary/ephemeral
1897 sslflags= Various flags modifying the use of SSL:
1899 Don't request client certificates
1900 immediately, but wait until acl processing
1901 requires a certificate (not yet implemented).
1903 Don't use the default CA lists built in
1906 Don't allow for session reuse. Each connection
1907 will result in a new SSL session.
1909 Verify CRL lists when accepting client
1912 Verify CRL lists for all certificates in the
1913 client certificate chain.
1915 sslcontext= SSL session ID context identifier.
1917 generate-host-certificates[=<on|off>]
1918 Dynamically create SSL server certificates for the
1919 destination hosts of bumped SSL requests.When
1920 enabled, the cert and key options are used to sign
1921 generated certificates. Otherwise generated
1922 certificate will be selfsigned.
1923 If there is CA certificate life time of generated
1924 certificate equals lifetime of CA certificate. If
1925 generated certificate is selfsigned lifetime is three
1927 This option is enabled by default when SslBump is used.
1928 See the sslBump option above for more information.
1930 dynamic_cert_mem_cache_size=SIZE
1931 Approximate total RAM size spent on cached generated
1932 certificates. If set to zero, caching is disabled. The
1933 default value is 4MB.
1935 See http_port for a list of available options.
1938 NAME: tcp_outgoing_tos tcp_outgoing_ds tcp_outgoing_dscp
1941 LOC: Ip::Qos::TheConfig.tosToServer
1943 Allows you to select a TOS/Diffserv value for packets outgoing
1944 on the server side, based on an ACL.
1946 tcp_outgoing_tos ds-field [!]aclname ...
1948 Example where normal_service_net uses the TOS value 0x00
1949 and good_service_net uses 0x20
1951 acl normal_service_net src 10.0.0.0/24
1952 acl good_service_net src 10.0.1.0/24
1953 tcp_outgoing_tos 0x00 normal_service_net
1954 tcp_outgoing_tos 0x20 good_service_net
1956 TOS/DSCP values really only have local significance - so you should
1957 know what you're specifying. For more information, see RFC2474,
1958 RFC2475, and RFC3260.
1960 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
1961 "default" to use whatever default your host has. Note that in
1962 practice often only multiples of 4 is usable as the two rightmost bits
1963 have been redefined for use by ECN (RFC 3168 section 23.1).
1965 Processing proceeds in the order specified, and stops at first fully
1969 NAME: clientside_tos
1972 LOC: Ip::Qos::TheConfig.tosToClient
1974 Allows you to select a TOS/Diffserv value for packets being transmitted
1975 on the client-side, based on an ACL.
1977 clientside_tos ds-field [!]aclname ...
1979 Example where normal_service_net uses the TOS value 0x00
1980 and good_service_net uses 0x20
1982 acl normal_service_net src 10.0.0.0/24
1983 acl good_service_net src 10.0.1.0/24
1984 clientside_tos 0x00 normal_service_net
1985 clientside_tos 0x20 good_service_net
1987 Note: This feature is incompatible with qos_flows. Any TOS values set here
1988 will be overwritten by TOS values in qos_flows.
1991 NAME: tcp_outgoing_mark
1993 IFDEF: SO_MARK&&USE_LIBCAP
1995 LOC: Ip::Qos::TheConfig.nfmarkToServer
1997 Allows you to apply a Netfilter mark value to outgoing packets
1998 on the server side, based on an ACL.
2000 tcp_outgoing_mark mark-value [!]aclname ...
2002 Example where normal_service_net uses the mark value 0x00
2003 and good_service_net uses 0x20
2005 acl normal_service_net src 10.0.0.0/24
2006 acl good_service_net src 10.0.1.0/24
2007 tcp_outgoing_mark 0x00 normal_service_net
2008 tcp_outgoing_mark 0x20 good_service_net
2011 NAME: clientside_mark
2013 IFDEF: SO_MARK&&USE_LIBCAP
2015 LOC: Ip::Qos::TheConfig.nfmarkToClient
2017 Allows you to apply a Netfilter mark value to packets being transmitted
2018 on the client-side, based on an ACL.
2020 clientside_mark mark-value [!]aclname ...
2022 Example where normal_service_net uses the mark value 0x00
2023 and good_service_net uses 0x20
2025 acl normal_service_net src 10.0.0.0/24
2026 acl good_service_net src 10.0.1.0/24
2027 clientside_mark 0x00 normal_service_net
2028 clientside_mark 0x20 good_service_net
2030 Note: This feature is incompatible with qos_flows. Any mark values set here
2031 will be overwritten by mark values in qos_flows.
2038 LOC: Ip::Qos::TheConfig
2040 Allows you to select a TOS/DSCP value to mark outgoing
2041 connections with, based on where the reply was sourced. For
2042 platforms using netfilter, allows you to set a netfilter mark
2043 value instead of, or in addition to, a TOS value.
2045 TOS values really only have local significance - so you should
2046 know what you're specifying. For more information, see RFC2474,
2047 RFC2475, and RFC3260.
2049 The TOS/DSCP byte must be exactly that - a octet value 0 - 255. Note that
2050 in practice often only multiples of 4 is usable as the two rightmost bits
2051 have been redefined for use by ECN (RFC 3168 section 23.1).
2053 Mark values can be any unsigned 32-bit integer value.
2055 This setting is configured by setting the following values:
2057 tos|mark Whether to set TOS or netfilter mark values
2059 local-hit=0xFF Value to mark local cache hits.
2061 sibling-hit=0xFF Value to mark hits from sibling peers.
2063 parent-hit=0xFF Value to mark hits from parent peers.
2065 miss=0xFF[/mask] Value to mark cache misses. Takes precedence
2066 over the preserve-miss feature (see below), unless
2067 mask is specified, in which case only the bits
2068 specified in the mask are written.
2070 The TOS variant of the following features are only possible on Linux
2071 and require your kernel to be patched with the TOS preserving ZPH
2072 patch, available from http://zph.bratcheda.org
2073 No patch is needed to preserve the netfilter mark, which will work
2074 with all variants of netfilter.
2076 disable-preserve-miss
2077 This option disables the preservation of the TOS or netfilter
2078 mark. By default, the existing TOS or netfilter mark value of
2079 the response coming from the remote server will be retained
2080 and masked with miss-mark.
2081 NOTE: in the case of a netfilter mark, the mark must be set on
2082 the connection (using the CONNMARK target) not on the packet
2086 Allows you to mask certain bits in the TOS or mark value
2087 received from the remote server, before copying the value to
2088 the TOS sent towards clients.
2089 Default for tos: 0xFF (TOS from server is not changed).
2090 Default for mark: 0xFFFFFFFF (mark from server is not changed).
2092 All of these features require the --enable-zph-qos compilation flag
2093 (enabled by default). Netfilter marking also requires the
2094 libnetfilter_conntrack libraries (--with-netfilter-conntrack) and
2095 libcap 2.09+ (--with-libcap).
2099 NAME: tcp_outgoing_address
2102 DEFAULT_DOC: Address selection is performed by the operating system.
2103 LOC: Config.accessList.outgoing_address
2105 Allows you to map requests to different outgoing IP addresses
2106 based on the username or source address of the user making
2109 tcp_outgoing_address ipaddr [[!]aclname] ...
2112 Forwarding clients with dedicated IPs for certain subnets.
2114 acl normal_service_net src 10.0.0.0/24
2115 acl good_service_net src 10.0.2.0/24
2117 tcp_outgoing_address 2001:db8::c001 good_service_net
2118 tcp_outgoing_address 10.1.0.2 good_service_net
2120 tcp_outgoing_address 2001:db8::beef normal_service_net
2121 tcp_outgoing_address 10.1.0.1 normal_service_net
2123 tcp_outgoing_address 2001:db8::1
2124 tcp_outgoing_address 10.1.0.3
2126 Processing proceeds in the order specified, and stops at first fully
2129 Squid will add an implicit IP version test to each line.
2130 Requests going to IPv4 websites will use the outgoing 10.1.0.* addresses.
2131 Requests going to IPv6 websites will use the outgoing 2001:db8:* addresses.
2134 NOTE: The use of this directive using client dependent ACLs is
2135 incompatible with the use of server side persistent connections. To
2136 ensure correct results it is best to set server_persistent_connections
2137 to off when using this directive in such configurations.
2139 NOTE: The use of this directive to set a local IP on outgoing TCP links
2140 is incompatible with using TPROXY to set client IP out outbound TCP links.
2141 When needing to contact peers use the no-tproxy cache_peer option and the
2142 client_dst_passthru directive re-enable normal forwarding such as this.
2146 NAME: host_verify_strict
2149 LOC: Config.onoff.hostStrictVerify
2151 Regardless of this option setting, when dealing with intercepted
2152 traffic, Squid always verifies that the destination IP address matches
2153 the Host header domain or IP (called 'authority form URL').
2155 This enforcement is performed to satisfy a MUST-level requirement in
2156 RFC 2616 section 14.23: "The Host field value MUST represent the naming
2157 authority of the origin server or gateway given by the original URL".
2160 Squid always responds with an HTTP 409 (Conflict) error
2161 page and logs a security warning if there is no match.
2163 Squid verifies that the destination IP address matches
2164 the Host header for forward-proxy and reverse-proxy traffic
2165 as well. For those traffic types, Squid also enables the
2166 following checks, comparing the corresponding Host header
2167 and Request-URI components:
2169 * The host names (domain or IP) must be identical,
2170 but valueless or missing Host header disables all checks.
2171 For the two host names to match, both must be either IP
2174 * Port numbers must be identical, but if a port is missing
2175 the scheme-default port is assumed.
2178 When set to OFF (the default):
2179 Squid allows suspicious requests to continue but logs a
2180 security warning and blocks caching of the response.
2182 * Forward-proxy traffic is not checked at all.
2184 * Reverse-proxy traffic is not checked at all.
2186 * Intercepted traffic which passes verification is handled
2187 according to client_dst_passthru.
2189 * Intercepted requests which fail verification are sent
2190 to the client original destination instead of DIRECT.
2191 This overrides 'client_dst_passthru off'.
2193 For now suspicious intercepted CONNECT requests are always
2194 responded to with an HTTP 409 (Conflict) error page.
2199 As described in CVE-2009-0801 when the Host: header alone is used
2200 to determine the destination of a request it becomes trivial for
2201 malicious scripts on remote websites to bypass browser same-origin
2202 security policy and sandboxing protections.
2204 The cause of this is that such applets are allowed to perform their
2205 own HTTP stack, in which case the same-origin policy of the browser
2206 sandbox only verifies that the applet tries to contact the same IP
2207 as from where it was loaded at the IP level. The Host: header may
2208 be different from the connected IP and approved origin.
2212 NAME: client_dst_passthru
2215 LOC: Config.onoff.client_dst_passthru
2217 With NAT or TPROXY intercepted traffic Squid may pass the request
2218 directly to the original client destination IP or seek a faster
2219 source using the HTTP Host header.
2221 Using Host to locate alternative servers can provide faster
2222 connectivity with a range of failure recovery options.
2223 But can also lead to connectivity trouble when the client and
2224 server are attempting stateful interactions unaware of the proxy.
2226 This option (on by default) prevents alternative DNS entries being
2227 located to send intercepted traffic DIRECT to an origin server.
2228 The clients original destination IP and port will be used instead.
2230 Regardless of this option setting, when dealing with intercepted
2231 traffic Squid will verify the Host: header and any traffic which
2232 fails Host verification will be treated as if this option were ON.
2234 see host_verify_strict for details on the verification process.
2239 -----------------------------------------------------------------------------
2242 NAME: ssl_unclean_shutdown
2246 LOC: Config.SSL.unclean_shutdown
2248 Some browsers (especially MSIE) bugs out on SSL shutdown
2255 LOC: Config.SSL.ssl_engine
2258 The OpenSSL engine to use. You will need to set this if you
2259 would like to use hardware SSL acceleration for example.
2262 NAME: sslproxy_client_certificate
2265 LOC: Config.ssl_client.cert
2268 Client SSL Certificate to use when proxying https:// URLs
2271 NAME: sslproxy_client_key
2274 LOC: Config.ssl_client.key
2277 Client SSL Key to use when proxying https:// URLs
2280 NAME: sslproxy_version
2283 DEFAULT_DOC: automatic SSL/TLS version negotiation
2284 LOC: Config.ssl_client.version
2287 SSL version level to use when proxying https:// URLs
2289 The versions of SSL/TLS supported:
2291 1 automatic (default)
2299 NAME: sslproxy_options
2302 LOC: Config.ssl_client.options
2305 SSL implementation options to use when proxying https:// URLs
2307 The most important being:
2309 NO_SSLv2 Disallow the use of SSLv2
2310 NO_SSLv3 Disallow the use of SSLv3
2311 NO_TLSv1 Disallow the use of TLSv1.0
2312 NO_TLSv1_1 Disallow the use of TLSv1.1
2313 NO_TLSv1_2 Disallow the use of TLSv1.2
2315 Always create a new key when using temporary/ephemeral
2318 Disable use of RFC5077 session tickets. Some servers
2319 may have problems understanding the TLS extension due
2320 to ambiguous specification in RFC4507.
2321 ALL Enable various bug workarounds suggested as "harmless"
2322 by OpenSSL. Be warned that this may reduce SSL/TLS
2323 strength to some attacks.
2325 See the OpenSSL SSL_CTX_set_options documentation for a
2326 complete list of possible options.
2329 NAME: sslproxy_cipher
2332 LOC: Config.ssl_client.cipher
2335 SSL cipher list to use when proxying https:// URLs
2337 Colon separated list of supported ciphers.
2340 NAME: sslproxy_cafile
2343 LOC: Config.ssl_client.cafile
2346 file containing CA certificates to use when verifying server
2347 certificates while proxying https:// URLs
2350 NAME: sslproxy_capath
2353 LOC: Config.ssl_client.capath
2356 directory containing CA certificates to use when verifying
2357 server certificates while proxying https:// URLs
2362 TYPE: sslproxy_ssl_bump
2363 LOC: Config.accessList.ssl_bump
2364 DEFAULT_DOC: Does not bump unless rules are present in squid.conf
2367 This option is consulted when a CONNECT request is received on
2368 an http_port (or a new connection is intercepted at an
2369 https_port), provided that port was configured with an ssl-bump
2370 flag. The subsequent data on the connection is either treated as
2371 HTTPS and decrypted OR tunneled at TCP level without decryption,
2372 depending on the first bumping "mode" which ACLs match.
2374 ssl_bump <mode> [!]acl ...
2376 The following bumping modes are supported:
2379 Allow bumping of the connection. Establish a secure connection
2380 with the client first, then connect to the server. This old mode
2381 does not allow Squid to mimic server SSL certificate and does
2382 not work with intercepted SSL connections.
2385 Allow bumping of the connection. Establish a secure connection
2386 with the server first, then establish a secure connection with
2387 the client, using a mimicked server certificate. Works with both
2388 CONNECT requests and intercepted SSL connections.
2391 Become a TCP tunnel without decoding the connection.
2392 Works with both CONNECT requests and intercepted SSL
2393 connections. This is the default behavior when no
2394 ssl_bump option is given or no ssl_bump ACLs match.
2396 By default, no connections are bumped.
2398 The first matching ssl_bump option wins. If no ACLs match, the
2399 connection is not bumped. Unlike most allow/deny ACL lists, ssl_bump
2400 does not have an implicit "negate the last given option" rule. You
2401 must make that rule explicit if you convert old ssl_bump allow/deny
2402 rules that rely on such an implicit rule.
2404 This clause supports both fast and slow acl types.
2405 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2407 See also: http_port ssl-bump, https_port ssl-bump
2410 # Example: Bump all requests except those originating from
2411 # localhost or those going to example.com.
2413 acl broken_sites dstdomain .example.com
2414 ssl_bump none localhost
2415 ssl_bump none broken_sites
2416 ssl_bump server-first all
2419 NAME: sslproxy_flags
2422 LOC: Config.ssl_client.flags
2425 Various flags modifying the use of SSL while proxying https:// URLs:
2426 DONT_VERIFY_PEER Accept certificates that fail verification.
2427 For refined control, see sslproxy_cert_error.
2428 NO_DEFAULT_CA Don't use the default CA list built in
2432 NAME: sslproxy_cert_error
2435 DEFAULT_DOC: Server certificate errors terminate the transaction.
2436 LOC: Config.ssl_client.cert_error
2439 Use this ACL to bypass server certificate validation errors.
2441 For example, the following lines will bypass all validation errors
2442 when talking to servers for example.com. All other
2443 validation errors will result in ERR_SECURE_CONNECT_FAIL error.
2445 acl BrokenButTrustedServers dstdomain example.com
2446 sslproxy_cert_error allow BrokenButTrustedServers
2447 sslproxy_cert_error deny all
2449 This clause only supports fast acl types.
2450 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2451 Using slow acl types may result in server crashes
2453 Without this option, all server certificate validation errors
2454 terminate the transaction to protect Squid and the client.
2456 SQUID_X509_V_ERR_INFINITE_VALIDATION error cannot be bypassed
2457 but should not happen unless your OpenSSL library is buggy.
2460 Bypassing validation errors is dangerous because an
2461 error usually implies that the server cannot be trusted
2462 and the connection may be insecure.
2464 See also: sslproxy_flags and DONT_VERIFY_PEER.
2467 NAME: sslproxy_cert_sign
2470 POSTSCRIPTUM: signUntrusted ssl::certUntrusted
2471 POSTSCRIPTUM: signSelf ssl::certSelfSigned
2472 POSTSCRIPTUM: signTrusted all
2473 TYPE: sslproxy_cert_sign
2474 LOC: Config.ssl_client.cert_sign
2477 sslproxy_cert_sign <signing algorithm> acl ...
2479 The following certificate signing algorithms are supported:
2482 Sign using the configured CA certificate which is usually
2483 placed in and trusted by end-user browsers. This is the
2484 default for trusted origin server certificates.
2487 Sign to guarantee an X509_V_ERR_CERT_UNTRUSTED browser error.
2488 This is the default for untrusted origin server certificates
2489 that are not self-signed (see ssl::certUntrusted).
2492 Sign using a self-signed certificate with the right CN to
2493 generate a X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT error in the
2494 browser. This is the default for self-signed origin server
2495 certificates (see ssl::certSelfSigned).
2497 This clause only supports fast acl types.
2499 When sslproxy_cert_sign acl(s) match, Squid uses the corresponding
2500 signing algorithm to generate the certificate and ignores all
2501 subsequent sslproxy_cert_sign options (the first match wins). If no
2502 acl(s) match, the default signing algorithm is determined by errors
2503 detected when obtaining and validating the origin server certificate.
2505 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2506 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2507 CONNECT request that carries a domain name. In all other cases (CONNECT
2508 to an IP address or an intercepted SSL connection), Squid cannot detect
2509 the domain mismatch at certificate generation time when
2510 bump-server-first is used.
2513 NAME: sslproxy_cert_adapt
2516 TYPE: sslproxy_cert_adapt
2517 LOC: Config.ssl_client.cert_adapt
2520 sslproxy_cert_adapt <adaptation algorithm> acl ...
2522 The following certificate adaptation algorithms are supported:
2525 Sets the "Not After" property to the "Not After" property of
2526 the CA certificate used to sign generated certificates.
2529 Sets the "Not Before" property to the "Not Before" property of
2530 the CA certificate used to sign generated certificates.
2532 setCommonName or setCommonName{CN}
2533 Sets Subject.CN property to the host name specified as a
2534 CN parameter or, if no explicit CN parameter was specified,
2535 extracted from the CONNECT request. It is a misconfiguration
2536 to use setCommonName without an explicit parameter for
2537 intercepted or tproxied SSL connections.
2539 This clause only supports fast acl types.
2541 Squid first groups sslproxy_cert_adapt options by adaptation algorithm.
2542 Within a group, when sslproxy_cert_adapt acl(s) match, Squid uses the
2543 corresponding adaptation algorithm to generate the certificate and
2544 ignores all subsequent sslproxy_cert_adapt options in that algorithm's
2545 group (i.e., the first match wins within each algorithm group). If no
2546 acl(s) match, the default mimicking action takes place.
2548 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2549 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2550 CONNECT request that carries a domain name. In all other cases (CONNECT
2551 to an IP address or an intercepted SSL connection), Squid cannot detect
2552 the domain mismatch at certificate generation time when
2553 bump-server-first is used.
2556 NAME: sslpassword_program
2559 LOC: Config.Program.ssl_password
2562 Specify a program used for entering SSL key passphrases
2563 when using encrypted SSL certificate keys. If not specified
2564 keys must either be unencrypted, or Squid started with the -N
2565 option to allow it to query interactively for the passphrase.
2567 The key file name is given as argument to the program allowing
2568 selection of the right password if you have multiple encrypted
2573 OPTIONS RELATING TO EXTERNAL SSL_CRTD
2574 -----------------------------------------------------------------------------
2577 NAME: sslcrtd_program
2580 DEFAULT: @DEFAULT_SSL_CRTD@ -s @DEFAULT_SSL_DB_DIR@ -M 4MB
2581 LOC: Ssl::TheConfig.ssl_crtd
2583 Specify the location and options of the executable for ssl_crtd process.
2584 @DEFAULT_SSL_CRTD@ program requires -s and -M parameters
2585 For more information use:
2586 @DEFAULT_SSL_CRTD@ -h
2589 NAME: sslcrtd_children
2590 TYPE: HelperChildConfig
2592 DEFAULT: 32 startup=5 idle=1
2593 LOC: Ssl::TheConfig.ssl_crtdChildren
2595 The maximum number of processes spawn to service ssl server.
2596 The maximum this may be safely set to is 32.
2598 The startup= and idle= options allow some measure of skew in your
2603 Sets the minimum number of processes to spawn when Squid
2604 starts or reconfigures. When set to zero the first request will
2605 cause spawning of the first child process to handle it.
2607 Starting too few children temporary slows Squid under load while it
2608 tries to spawn enough additional processes to cope with traffic.
2612 Sets a minimum of how many processes Squid is to try and keep available
2613 at all times. When traffic begins to rise above what the existing
2614 processes can handle this many more will be spawned up to the maximum
2615 configured. A minimum setting of 1 is required.
2617 You must have at least one ssl_crtd process.
2620 NAME: sslcrtvalidator_program
2624 LOC: Ssl::TheConfig.ssl_crt_validator
2626 Specify the location and options of the executable for ssl_crt_validator
2629 Usage: sslcrtvalidator_program [ttl=n] [cache=n] path ...
2632 ttl=n TTL in seconds for cached results. The default is 60 secs
2633 cache=n limit the result cache size. The default value is 2048
2636 NAME: sslcrtvalidator_children
2637 TYPE: HelperChildConfig
2639 DEFAULT: 32 startup=5 idle=1 concurrency=1
2640 LOC: Ssl::TheConfig.ssl_crt_validator_Children
2642 The maximum number of processes spawn to service SSL server.
2643 The maximum this may be safely set to is 32.
2645 The startup= and idle= options allow some measure of skew in your
2650 Sets the minimum number of processes to spawn when Squid
2651 starts or reconfigures. When set to zero the first request will
2652 cause spawning of the first child process to handle it.
2654 Starting too few children temporary slows Squid under load while it
2655 tries to spawn enough additional processes to cope with traffic.
2659 Sets a minimum of how many processes Squid is to try and keep available
2660 at all times. When traffic begins to rise above what the existing
2661 processes can handle this many more will be spawned up to the maximum
2662 configured. A minimum setting of 1 is required.
2666 The number of requests each certificate validator helper can handle in
2667 parallel. Defaults to 0 which indicates the certficate validator
2668 is a old-style single threaded redirector.
2670 When this directive is set to a value >= 1 then the protocol
2671 used to communicate with the helper is modified to include
2672 a request ID in front of the request/response. The request
2673 ID from the request must be echoed back with the response
2676 You must have at least one ssl_crt_validator process.
2680 OPTIONS WHICH AFFECT THE NEIGHBOR SELECTION ALGORITHM
2681 -----------------------------------------------------------------------------
2689 To specify other caches in a hierarchy, use the format:
2691 cache_peer hostname type http-port icp-port [options]
2696 # hostname type port port options
2697 # -------------------- -------- ----- ----- -----------
2698 cache_peer parent.foo.net parent 3128 3130 default
2699 cache_peer sib1.foo.net sibling 3128 3130 proxy-only
2700 cache_peer sib2.foo.net sibling 3128 3130 proxy-only
2701 cache_peer example.com parent 80 0 default
2702 cache_peer cdn.example.com sibling 3128 0
2704 type: either 'parent', 'sibling', or 'multicast'.
2706 proxy-port: The port number where the peer accept HTTP requests.
2707 For other Squid proxies this is usually 3128
2708 For web servers this is usually 80
2710 icp-port: Used for querying neighbor caches about objects.
2711 Set to 0 if the peer does not support ICP or HTCP.
2712 See ICP and HTCP options below for additional details.
2715 ==== ICP OPTIONS ====
2717 You MUST also set icp_port and icp_access explicitly when using these options.
2718 The defaults will prevent peer traffic using ICP.
2721 no-query Disable ICP queries to this neighbor.
2724 Indicates the named peer is a member of a multicast group.
2725 ICP queries will not be sent directly to the peer, but ICP
2726 replies will be accepted from it.
2728 closest-only Indicates that, for ICP_OP_MISS replies, we'll only forward
2729 CLOSEST_PARENT_MISSes and never FIRST_PARENT_MISSes.
2732 To only send ICP queries to this neighbor infrequently.
2733 This is used to keep the neighbor round trip time updated
2734 and is usually used in conjunction with weighted-round-robin.
2737 ==== HTCP OPTIONS ====
2739 You MUST also set htcp_port and htcp_access explicitly when using these options.
2740 The defaults will prevent peer traffic using HTCP.
2743 htcp Send HTCP, instead of ICP, queries to the neighbor.
2744 You probably also want to set the "icp-port" to 4827
2745 instead of 3130. This directive accepts a comma separated
2746 list of options described below.
2748 htcp=oldsquid Send HTCP to old Squid versions (2.5 or earlier).
2750 htcp=no-clr Send HTCP to the neighbor but without
2751 sending any CLR requests. This cannot be used with
2754 htcp=only-clr Send HTCP to the neighbor but ONLY CLR requests.
2755 This cannot be used with no-clr.
2758 Send HTCP to the neighbor including CLRs but only when
2759 they do not result from PURGE requests.
2762 Forward any HTCP CLR requests this proxy receives to the peer.
2765 ==== PEER SELECTION METHODS ====
2767 The default peer selection method is ICP, with the first responding peer
2768 being used as source. These options can be used for better load balancing.
2771 default This is a parent cache which can be used as a "last-resort"
2772 if a peer cannot be located by any of the peer-selection methods.
2773 If specified more than once, only the first is used.
2775 round-robin Load-Balance parents which should be used in a round-robin
2776 fashion in the absence of any ICP queries.
2777 weight=N can be used to add bias.
2779 weighted-round-robin
2780 Load-Balance parents which should be used in a round-robin
2781 fashion with the frequency of each parent being based on the
2782 round trip time. Closer parents are used more often.
2783 Usually used for background-ping parents.
2784 weight=N can be used to add bias.
2786 carp Load-Balance parents which should be used as a CARP array.
2787 The requests will be distributed among the parents based on the
2788 CARP load balancing hash function based on their weight.
2790 userhash Load-balance parents based on the client proxy_auth or ident username.
2792 sourcehash Load-balance parents based on the client source IP.
2795 To be used only for cache peers of type "multicast".
2796 ALL members of this multicast group have "sibling"
2797 relationship with it, not "parent". This is to a multicast
2798 group when the requested object would be fetched only from
2799 a "parent" cache, anyway. It's useful, e.g., when
2800 configuring a pool of redundant Squid proxies, being
2801 members of the same multicast group.
2804 ==== PEER SELECTION OPTIONS ====
2806 weight=N use to affect the selection of a peer during any weighted
2807 peer-selection mechanisms.
2808 The weight must be an integer; default is 1,
2809 larger weights are favored more.
2810 This option does not affect parent selection if a peering
2811 protocol is not in use.
2813 basetime=N Specify a base amount to be subtracted from round trip
2815 It is subtracted before division by weight in calculating
2816 which parent to fectch from. If the rtt is less than the
2817 base time the rtt is set to a minimal value.
2819 ttl=N Specify a TTL to use when sending multicast ICP queries
2821 Only useful when sending to a multicast group.
2822 Because we don't accept ICP replies from random
2823 hosts, you must configure other group members as
2824 peers with the 'multicast-responder' option.
2826 no-delay To prevent access to this neighbor from influencing the
2829 digest-url=URL Tell Squid to fetch the cache digest (if digests are
2830 enabled) for this host from the specified URL rather
2831 than the Squid default location.
2834 ==== CARP OPTIONS ====
2836 carp-key=key-specification
2837 use a different key than the full URL to hash against the peer.
2838 the key-specification is a comma-separated list of the keywords
2839 scheme, host, port, path, params
2840 Order is not important.
2842 ==== ACCELERATOR / REVERSE-PROXY OPTIONS ====
2844 originserver Causes this parent to be contacted as an origin server.
2845 Meant to be used in accelerator setups when the peer
2849 Set the Host header of requests forwarded to this peer.
2850 Useful in accelerator setups where the server (peer)
2851 expects a certain domain name but clients may request
2852 others. ie example.com or www.example.com
2854 no-digest Disable request of cache digests.
2857 Disables requesting ICMP RTT database (NetDB).
2860 ==== AUTHENTICATION OPTIONS ====
2863 If this is a personal/workgroup proxy and your parent
2864 requires proxy authentication.
2866 Note: The string can include URL escapes (i.e. %20 for
2867 spaces). This also means % must be written as %%.
2870 Send login details received from client to this peer.
2871 Both Proxy- and WWW-Authorization headers are passed
2872 without alteration to the peer.
2873 Authentication is not required by Squid for this to work.
2875 Note: This will pass any form of authentication but
2876 only Basic auth will work through a proxy unless the
2877 connection-auth options are also used.
2879 login=PASS Send login details received from client to this peer.
2880 Authentication is not required by this option.
2882 If there are no client-provided authentication headers
2883 to pass on, but username and password are available
2884 from an external ACL user= and password= result tags
2885 they may be sent instead.
2887 Note: To combine this with proxy_auth both proxies must
2888 share the same user database as HTTP only allows for
2889 a single login (one for proxy, one for origin server).
2890 Also be warned this will expose your users proxy
2891 password to the peer. USE WITH CAUTION
2894 Send the username to the upstream cache, but with a
2895 fixed password. This is meant to be used when the peer
2896 is in another administrative domain, but it is still
2897 needed to identify each user.
2898 The star can optionally be followed by some extra
2899 information which is added to the username. This can
2900 be used to identify this proxy to the peer, similar to
2901 the login=username:password option above.
2904 If this is a personal/workgroup proxy and your parent
2905 requires a secure proxy authentication.
2906 The first principal from the default keytab or defined by
2907 the environment variable KRB5_KTNAME will be used.
2909 WARNING: The connection may transmit requests from multiple
2910 clients. Negotiate often assumes end-to-end authentication
2911 and a single-client. Which is not strictly true here.
2913 login=NEGOTIATE:principal_name
2914 If this is a personal/workgroup proxy and your parent
2915 requires a secure proxy authentication.
2916 The principal principal_name from the default keytab or
2917 defined by the environment variable KRB5_KTNAME will be
2920 WARNING: The connection may transmit requests from multiple
2921 clients. Negotiate often assumes end-to-end authentication
2922 and a single-client. Which is not strictly true here.
2924 connection-auth=on|off
2925 Tell Squid that this peer does or not support Microsoft
2926 connection oriented authentication, and any such
2927 challenges received from there should be ignored.
2928 Default is auto to automatically determine the status
2932 ==== SSL / HTTPS / TLS OPTIONS ====
2934 ssl Encrypt connections to this peer with SSL/TLS.
2936 sslcert=/path/to/ssl/certificate
2937 A client SSL certificate to use when connecting to
2940 sslkey=/path/to/ssl/key
2941 The private SSL key corresponding to sslcert above.
2942 If 'sslkey' is not specified 'sslcert' is assumed to
2943 reference a combined file containing both the
2944 certificate and the key.
2946 sslversion=1|2|3|4|5|6
2947 The SSL version to use when connecting to this peer
2948 1 = automatic (default)
2955 sslcipher=... The list of valid SSL ciphers to use when connecting
2958 ssloptions=... Specify various SSL implementation options:
2960 NO_SSLv2 Disallow the use of SSLv2
2961 NO_SSLv3 Disallow the use of SSLv3
2962 NO_TLSv1 Disallow the use of TLSv1.0
2963 NO_TLSv1_1 Disallow the use of TLSv1.1
2964 NO_TLSv1_2 Disallow the use of TLSv1.2
2966 Always create a new key when using
2967 temporary/ephemeral DH key exchanges
2968 ALL Enable various bug workarounds
2969 suggested as "harmless" by OpenSSL
2970 Be warned that this reduces SSL/TLS
2971 strength to some attacks.
2973 See the OpenSSL SSL_CTX_set_options documentation for a
2976 sslcafile=... A file containing additional CA certificates to use
2977 when verifying the peer certificate.
2979 sslcapath=... A directory containing additional CA certificates to
2980 use when verifying the peer certificate.
2982 sslcrlfile=... A certificate revocation list file to use when
2983 verifying the peer certificate.
2985 sslflags=... Specify various flags modifying the SSL implementation:
2988 Accept certificates even if they fail to
2991 Don't use the default CA list built in
2994 Don't verify the peer certificate
2995 matches the server name
2997 ssldomain= The peer name as advertised in it's certificate.
2998 Used for verifying the correctness of the received peer
2999 certificate. If not specified the peer hostname will be
3003 Enable the "Front-End-Https: On" header needed when
3004 using Squid as a SSL frontend in front of Microsoft OWA.
3005 See MS KB document Q307347 for details on this header.
3006 If set to auto the header will only be added if the
3007 request is forwarded as a https:// URL.
3010 ==== GENERAL OPTIONS ====
3013 A peer-specific connect timeout.
3014 Also see the peer_connect_timeout directive.
3016 connect-fail-limit=N
3017 How many times connecting to a peer must fail before
3018 it is marked as down. Default is 10.
3020 allow-miss Disable Squid's use of only-if-cached when forwarding
3021 requests to siblings. This is primarily useful when
3022 icp_hit_stale is used by the sibling. To extensive use
3023 of this option may result in forwarding loops, and you
3024 should avoid having two-way peerings with this option.
3025 For example to deny peer usage on requests from peer
3026 by denying cache_peer_access if the source is a peer.
3028 max-conn=N Limit the amount of connections Squid may open to this
3031 name=xxx Unique name for the peer.
3032 Required if you have multiple peers on the same host
3033 but different ports.
3034 This name can be used in cache_peer_access and similar
3035 directives to dentify the peer.
3036 Can be used by outgoing access controls through the
3039 no-tproxy Do not use the client-spoof TPROXY support when forwarding
3040 requests to this peer. Use normal address selection instead.
3041 This overrides the spoof_client_ip ACL.
3043 proxy-only objects fetched from the peer will not be stored locally.
3047 NAME: cache_peer_domain cache_host_domain
3052 Use to limit the domains for which a neighbor cache will be
3056 cache_peer_domain cache-host domain [domain ...]
3057 cache_peer_domain cache-host !domain
3059 For example, specifying
3061 cache_peer_domain parent.foo.net .edu
3063 has the effect such that UDP query packets are sent to
3064 'bigserver' only when the requested object exists on a
3065 server in the .edu domain. Prefixing the domainname
3066 with '!' means the cache will be queried for objects
3069 NOTE: * Any number of domains may be given for a cache-host,
3070 either on the same or separate lines.
3071 * When multiple domains are given for a particular
3072 cache-host, the first matched domain is applied.
3073 * Cache hosts with no domain restrictions are queried
3075 * There are no defaults.
3076 * There is also a 'cache_peer_access' tag in the ACL
3080 NAME: cache_peer_access
3085 Similar to 'cache_peer_domain' but provides more flexibility by
3089 cache_peer_access cache-host allow|deny [!]aclname ...
3091 The syntax is identical to 'http_access' and the other lists of
3092 ACL elements. See the comments for 'http_access' below, or
3093 the Squid FAQ (http://wiki.squid-cache.org/SquidFaq/SquidAcl).
3096 NAME: neighbor_type_domain
3097 TYPE: hostdomaintype
3099 DEFAULT_DOC: The peer type from cache_peer directive is used for all requests to that peer.
3102 Modify the cache_peer neighbor type when passing requests
3103 about specific domains to the peer.
3106 neighbor_type_domain neighbor parent|sibling domain domain ...
3109 cache_peer foo.example.com parent 3128 3130
3110 neighbor_type_domain foo.example.com sibling .au .de
3112 The above configuration treats all requests to foo.example.com as a
3113 parent proxy unless the request is for a .au or .de ccTLD domain name.
3116 NAME: dead_peer_timeout
3120 LOC: Config.Timeout.deadPeer
3122 This controls how long Squid waits to declare a peer cache
3123 as "dead." If there are no ICP replies received in this
3124 amount of time, Squid will declare the peer dead and not
3125 expect to receive any further ICP replies. However, it
3126 continues to send ICP queries, and will mark the peer as
3127 alive upon receipt of the first subsequent ICP reply.
3129 This timeout also affects when Squid expects to receive ICP
3130 replies from peers. If more than 'dead_peer' seconds have
3131 passed since the last ICP reply was received, Squid will not
3132 expect to receive an ICP reply on the next query. Thus, if
3133 your time between requests is greater than this timeout, you
3134 will see a lot of requests sent DIRECT to origin servers
3135 instead of to your parents.
3138 NAME: forward_max_tries
3141 LOC: Config.forward_max_tries
3143 Controls how many different forward paths Squid will try
3144 before giving up. See also forward_timeout.
3146 NOTE: connect_retries (default: none) can make each of these
3147 possible forwarding paths be tried multiple times.
3150 NAME: hierarchy_stoplist
3153 LOC: Config.hierarchy_stoplist
3155 A list of words which, if found in a URL, cause the object to
3156 be handled directly by this cache. In other words, use this
3157 to not query neighbor caches for certain objects. You may
3158 list this option multiple times.
3161 hierarchy_stoplist cgi-bin ?
3163 Note: never_direct overrides this option.
3167 MEMORY CACHE OPTIONS
3168 -----------------------------------------------------------------------------
3175 LOC: Config.memMaxSize
3177 NOTE: THIS PARAMETER DOES NOT SPECIFY THE MAXIMUM PROCESS SIZE.
3178 IT ONLY PLACES A LIMIT ON HOW MUCH ADDITIONAL MEMORY SQUID WILL
3179 USE AS A MEMORY CACHE OF OBJECTS. SQUID USES MEMORY FOR OTHER
3180 THINGS AS WELL. SEE THE SQUID FAQ SECTION 8 FOR DETAILS.
3182 'cache_mem' specifies the ideal amount of memory to be used
3184 * In-Transit objects
3186 * Negative-Cached objects
3188 Data for these objects are stored in 4 KB blocks. This
3189 parameter specifies the ideal upper limit on the total size of
3190 4 KB blocks allocated. In-Transit objects take the highest
3193 In-transit objects have priority over the others. When
3194 additional space is needed for incoming data, negative-cached
3195 and hot objects will be released. In other words, the
3196 negative-cached and hot objects will fill up any unused space
3197 not needed for in-transit objects.
3199 If circumstances require, this limit will be exceeded.
3200 Specifically, if your incoming request rate requires more than
3201 'cache_mem' of memory to hold in-transit objects, Squid will
3202 exceed this limit to satisfy the new requests. When the load
3203 decreases, blocks will be freed until the high-water mark is
3204 reached. Thereafter, blocks will be used to store hot
3207 If shared memory caching is enabled, Squid does not use the shared
3208 cache space for in-transit objects, but they still consume as much
3209 local memory as they need. For more details about the shared memory
3210 cache, see memory_cache_shared.
3213 NAME: maximum_object_size_in_memory
3217 LOC: Config.Store.maxInMemObjSize
3219 Objects greater than this size will not be attempted to kept in
3220 the memory cache. This should be set high enough to keep objects
3221 accessed frequently in memory to improve performance whilst low
3222 enough to keep larger objects from hoarding cache_mem.
3225 NAME: memory_cache_shared
3228 LOC: Config.memShared
3230 DEFAULT_DOC: "on" where supported if doing memory caching with multiple SMP workers.
3232 Controls whether the memory cache is shared among SMP workers.
3234 The shared memory cache is meant to occupy cache_mem bytes and replace
3235 the non-shared memory cache, although some entities may still be
3236 cached locally by workers for now (e.g., internal and in-transit
3237 objects may be served from a local memory cache even if shared memory
3238 caching is enabled).
3240 By default, the memory cache is shared if and only if all of the
3241 following conditions are satisfied: Squid runs in SMP mode with
3242 multiple workers, cache_mem is positive, and Squid environment
3243 supports required IPC primitives (e.g., POSIX shared memory segments
3244 and GCC-style atomic operations).
3246 To avoid blocking locks, shared memory uses opportunistic algorithms
3247 that do not guarantee that every cachable entity that could have been
3248 shared among SMP workers will actually be shared.
3250 Currently, entities exceeding 32KB in size cannot be shared.
3253 NAME: memory_cache_mode
3257 DEFAULT_DOC: Keep the most recently fetched objects in memory
3259 Controls which objects to keep in the memory cache (cache_mem)
3261 always Keep most recently fetched objects in memory (default)
3263 disk Only disk cache hits are kept in memory, which means
3264 an object must first be cached on disk and then hit
3265 a second time before cached in memory.
3267 network Only objects fetched from network is kept in memory
3270 NAME: memory_replacement_policy
3272 LOC: Config.memPolicy
3275 The memory replacement policy parameter determines which
3276 objects are purged from memory when memory space is needed.
3278 See cache_replacement_policy for details on algorithms.
3283 -----------------------------------------------------------------------------
3286 NAME: cache_replacement_policy
3288 LOC: Config.replPolicy
3291 The cache replacement policy parameter determines which
3292 objects are evicted (replaced) when disk space is needed.
3294 lru : Squid's original list based LRU policy
3295 heap GDSF : Greedy-Dual Size Frequency
3296 heap LFUDA: Least Frequently Used with Dynamic Aging
3297 heap LRU : LRU policy implemented using a heap
3299 Applies to any cache_dir lines listed below this directive.
3301 The LRU policies keeps recently referenced objects.
3303 The heap GDSF policy optimizes object hit rate by keeping smaller
3304 popular objects in cache so it has a better chance of getting a
3305 hit. It achieves a lower byte hit rate than LFUDA though since
3306 it evicts larger (possibly popular) objects.
3308 The heap LFUDA policy keeps popular objects in cache regardless of
3309 their size and thus optimizes byte hit rate at the expense of
3310 hit rate since one large, popular object will prevent many
3311 smaller, slightly less popular objects from being cached.
3313 Both policies utilize a dynamic aging mechanism that prevents
3314 cache pollution that can otherwise occur with frequency-based
3315 replacement policies.
3317 NOTE: if using the LFUDA replacement policy you should increase
3318 the value of maximum_object_size above its default of 4 MB to
3319 to maximize the potential byte hit rate improvement of LFUDA.
3321 For more information about the GDSF and LFUDA cache replacement
3322 policies see http://www.hpl.hp.com/techreports/1999/HPL-1999-69.html
3323 and http://fog.hpl.external.hp.com/techreports/98/HPL-98-173.html.
3329 DEFAULT_DOC: No disk cache. Store cache ojects only in memory.
3330 LOC: Config.cacheSwap
3333 cache_dir Type Directory-Name Fs-specific-data [options]
3335 You can specify multiple cache_dir lines to spread the
3336 cache among different disk partitions.
3338 Type specifies the kind of storage system to use. Only "ufs"
3339 is built by default. To enable any of the other storage systems
3340 see the --enable-storeio configure option.
3342 'Directory' is a top-level directory where cache swap
3343 files will be stored. If you want to use an entire disk
3344 for caching, this can be the mount-point directory.
3345 The directory must exist and be writable by the Squid
3346 process. Squid will NOT create this directory for you.
3348 In SMP configurations, cache_dir must not precede the workers option
3349 and should use configuration macros or conditionals to give each
3350 worker interested in disk caching a dedicated cache directory.
3353 ==== The ufs store type ====
3355 "ufs" is the old well-known Squid storage format that has always
3359 cache_dir ufs Directory-Name Mbytes L1 L2 [options]
3361 'Mbytes' is the amount of disk space (MB) to use under this
3362 directory. The default is 100 MB. Change this to suit your
3363 configuration. Do NOT put the size of your disk drive here.
3364 Instead, if you want Squid to use the entire disk drive,
3365 subtract 20% and use that value.
3367 'L1' is the number of first-level subdirectories which
3368 will be created under the 'Directory'. The default is 16.
3370 'L2' is the number of second-level subdirectories which
3371 will be created under each first-level directory. The default
3375 ==== The aufs store type ====
3377 "aufs" uses the same storage format as "ufs", utilizing
3378 POSIX-threads to avoid blocking the main Squid process on
3379 disk-I/O. This was formerly known in Squid as async-io.
3382 cache_dir aufs Directory-Name Mbytes L1 L2 [options]
3384 see argument descriptions under ufs above
3387 ==== The diskd store type ====
3389 "diskd" uses the same storage format as "ufs", utilizing a
3390 separate process to avoid blocking the main Squid process on
3394 cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n]
3396 see argument descriptions under ufs above
3398 Q1 specifies the number of unacknowledged I/O requests when Squid
3399 stops opening new files. If this many messages are in the queues,
3400 Squid won't open new files. Default is 64
3402 Q2 specifies the number of unacknowledged messages when Squid
3403 starts blocking. If this many messages are in the queues,
3404 Squid blocks until it receives some replies. Default is 72
3406 When Q1 < Q2 (the default), the cache directory is optimized
3407 for lower response time at the expense of a decrease in hit
3408 ratio. If Q1 > Q2, the cache directory is optimized for
3409 higher hit ratio at the expense of an increase in response
3413 ==== The rock store type ====
3416 cache_dir rock Directory-Name Mbytes <max-size=bytes> [options]
3418 The Rock Store type is a database-style storage. All cached
3419 entries are stored in a "database" file, using fixed-size slots,
3420 one entry per slot. The database size is specified in MB. The
3421 slot size is specified in bytes using the max-size option. See
3422 below for more info on the max-size option.
3424 If possible, Squid using Rock Store creates a dedicated kid
3425 process called "disker" to avoid blocking Squid worker(s) on disk
3426 I/O. One disker kid is created for each rock cache_dir. Diskers
3427 are created only when Squid, running in daemon mode, has support
3428 for the IpcIo disk I/O module.
3430 swap-timeout=msec: Squid will not start writing a miss to or
3431 reading a hit from disk if it estimates that the swap operation
3432 will take more than the specified number of milliseconds. By
3433 default and when set to zero, disables the disk I/O time limit
3434 enforcement. Ignored when using blocking I/O module because
3435 blocking synchronous I/O does not allow Squid to estimate the
3436 expected swap wait time.
3438 max-swap-rate=swaps/sec: Artificially limits disk access using
3439 the specified I/O rate limit. Swap out requests that
3440 would cause the average I/O rate to exceed the limit are
3441 delayed. Individual swap in requests (i.e., hits or reads) are
3442 not delayed, but they do contribute to measured swap rate and
3443 since they are placed in the same FIFO queue as swap out
3444 requests, they may wait longer if max-swap-rate is smaller.
3445 This is necessary on file systems that buffer "too
3446 many" writes and then start blocking Squid and other processes
3447 while committing those writes to disk. Usually used together
3448 with swap-timeout to avoid excessive delays and queue overflows
3449 when disk demand exceeds available disk "bandwidth". By default
3450 and when set to zero, disables the disk I/O rate limit
3451 enforcement. Currently supported by IpcIo module only.
3454 ==== The coss store type ====
3456 NP: COSS filesystem in Squid-3 has been deemed too unstable for
3457 production use and has thus been removed from this release.
3458 We hope that it can be made usable again soon.
3460 block-size=n defines the "block size" for COSS cache_dir's.
3461 Squid uses file numbers as block numbers. Since file numbers
3462 are limited to 24 bits, the block size determines the maximum
3463 size of the COSS partition. The default is 512 bytes, which
3464 leads to a maximum cache_dir size of 512<<24, or 8 GB. Note
3465 you should not change the coss block size after Squid
3466 has written some objects to the cache_dir.
3468 The coss file store has changed from 2.5. Now it uses a file
3469 called 'stripe' in the directory names in the config - and
3470 this will be created by squid -z.
3473 ==== COMMON OPTIONS ====
3475 no-store no new objects should be stored to this cache_dir.
3477 min-size=n the minimum object size in bytes this cache_dir
3478 will accept. It's used to restrict a cache_dir
3479 to only store large objects (e.g. AUFS) while
3480 other stores are optimized for smaller objects
3484 max-size=n the maximum object size in bytes this cache_dir
3486 The value in maximum_object_size directive, sets
3487 a default unless more specific details are available
3488 about the cache_dir (ie a small store capacity).
3490 Note: To make optimal use of the max-size limits you should order
3491 the cache_dir lines with the smallest max-size value first.
3493 Note for coss, max-size must be less than COSS_MEMBUF_SZ,
3494 which can be changed with the --with-coss-membuf-size=N configure
3499 # Uncomment and adjust the following to add a disk cache directory.
3500 #cache_dir ufs @DEFAULT_SWAP_DIR@ 100 16 256
3504 NAME: store_dir_select_algorithm
3506 LOC: Config.store_dir_select_algorithm
3509 How Squid selects which cache_dir to use when the response
3510 object will fit into more than one.
3512 Regardless of which algorithm is used the cache_dir min-size
3513 and max-size parameters are obeyed. As such they can affect
3514 the selection algorithm by limiting the set of considered
3521 This algorithm is suited to caches with similar cache_dir
3522 sizes and disk speeds.
3524 The disk with the least I/O pending is selected.
3525 When there are multiple disks with the same I/O load ranking
3526 the cache_dir with most available capacity is selected.
3528 When a mix of cache_dir sizes are configured the faster disks
3529 have a naturally lower I/O loading and larger disks have more
3530 capacity. So space used to store objects and data throughput
3531 may be very unbalanced towards larger disks.
3536 This algorithm is suited to caches with unequal cache_dir
3539 Each cache_dir is selected in a rotation. The next suitable
3542 Available cache_dir capacity is only considered in relation
3543 to whether the object will fit and meets the min-size and
3544 max-size parameters.
3546 Disk I/O loading is only considered to prevent overload on slow
3547 disks. This algorithm does not spread objects by size, so any
3548 I/O loading per-disk may appear very unbalanced and volatile.
3552 NAME: max_open_disk_fds
3554 LOC: Config.max_open_disk_fds
3556 DEFAULT_DOC: no limit
3558 To avoid having disk as the I/O bottleneck Squid can optionally
3559 bypass the on-disk cache if more than this amount of disk file
3560 descriptors are open.
3562 A value of 0 indicates no limit.
3565 NAME: minimum_object_size
3569 DEFAULT_DOC: no limit
3570 LOC: Config.Store.minObjectSize
3572 Objects smaller than this size will NOT be saved on disk. The
3573 value is specified in bytes, and the default is 0 KB, which
3574 means all responses can be stored.
3577 NAME: maximum_object_size
3581 LOC: Config.Store.maxObjectSize
3583 The default limit on size of objects stored to disk.
3584 This size is used for cache_dir where max-size is not set.
3585 The value is specified in bytes, and the default is 4 MB.
3587 If you wish to get a high BYTES hit ratio, you should probably
3588 increase this (one 32 MB object hit counts for 3200 10KB
3591 If you wish to increase hit ratio more than you want to
3592 save bandwidth you should leave this low.
3594 NOTE: if using the LFUDA replacement policy you should increase
3595 this value to maximize the byte hit rate improvement of LFUDA!
3596 See replacement_policy below for a discussion of this policy.
3599 NAME: cache_swap_low
3600 COMMENT: (percent, 0-100)
3603 LOC: Config.Swap.lowWaterMark
3605 The low-water mark for cache object replacement.
3606 Replacement begins when the swap (disk) usage is above the
3607 low-water mark and attempts to maintain utilization near the
3608 low-water mark. As swap utilization gets close to high-water
3609 mark object eviction becomes more aggressive. If utilization is
3610 close to the low-water mark less replacement is done each time.
3612 Defaults are 90% and 95%. If you have a large cache, 5% could be
3613 hundreds of MB. If this is the case you may wish to set these
3614 numbers closer together.
3616 See also cache_swap_high
3619 NAME: cache_swap_high
3620 COMMENT: (percent, 0-100)
3623 LOC: Config.Swap.highWaterMark
3625 The high-water mark for cache object replacement.
3626 Replacement begins when the swap (disk) usage is above the
3627 low-water mark and attempts to maintain utilization near the
3628 low-water mark. As swap utilization gets close to high-water
3629 mark object eviction becomes more aggressive. If utilization is
3630 close to the low-water mark less replacement is done each time.
3632 Defaults are 90% and 95%. If you have a large cache, 5% could be
3633 hundreds of MB. If this is the case you may wish to set these
3634 numbers closer together.
3636 See also cache_swap_low
3641 -----------------------------------------------------------------------------
3648 DEFAULT_DOC: The format definitions squid, common, combined, referrer, useragent are built in.
3652 logformat <name> <format specification>
3654 Defines an access log format.
3656 The <format specification> is a string with embedded % format codes
3658 % format codes all follow the same basic structure where all but
3659 the formatcode is optional. Output strings are automatically escaped
3660 as required according to their context and the output format
3661 modifiers are usually not needed, but can be specified if an explicit
3662 output format is desired.
3664 % ["|[|'|#] [-] [[0]width] [{argument}] formatcode
3666 " output in quoted string format
3667 [ output in squid text log format as used by log_mime_hdrs
3668 # output in URL quoted format
3673 width minimum and/or maximum field width:
3674 [width_min][.width_max]
3675 When minimum starts with 0, the field is zero-padded.
3676 String values exceeding maximum width are truncated.
3678 {arg} argument such as header name etc
3682 % a literal % character
3683 sn Unique sequence number per log line entry
3684 err_code The ID of an error response served by Squid or
3685 a similar internal error identifier.
3686 err_detail Additional err_code-dependent error information.
3687 note The meta header specified by the argument. Also
3688 logs the adaptation meta headers set by the
3689 adaptation_meta configuration parameter.
3690 If no argument given all meta headers logged.
3692 Connection related format codes:
3694 >a Client source IP address
3696 >p Client source port
3697 >eui Client source EUI (MAC address, EUI-48 or EUI-64 identifier)
3698 >la Local IP address the client connected to
3699 >lp Local port number the client connected to
3700 >qos Client connection TOS/DSCP value set by Squid
3701 >nfmark Client connection netfilter mark set by Squid
3703 la Local listening IP address the client connection was connected to.
3704 lp Local listening port number the client connection was connected to.
3706 <a Server IP address of the last server or peer connection
3707 <A Server FQDN or peer name
3708 <p Server port number of the last server or peer connection
3709 <la Local IP address of the last server or peer connection
3710 <lp Local port number of the last server or peer connection
3711 <qos Server connection TOS/DSCP value set by Squid
3712 <nfmark Server connection netfilter mark set by Squid
3714 Time related format codes:
3716 ts Seconds since epoch
3717 tu subsecond time (milliseconds)
3718 tl Local time. Optional strftime format argument
3719 default %d/%b/%Y:%H:%M:%S %z
3720 tg GMT time. Optional strftime format argument
3721 default %d/%b/%Y:%H:%M:%S %z
3722 tr Response time (milliseconds)
3723 dt Total time spent making DNS lookups (milliseconds)
3725 Access Control related format codes:
3727 et Tag returned by external acl
3728 ea Log string returned by external acl
3729 un User name (any available)
3730 ul User name from authentication
3731 ue User name from external acl helper
3732 ui User name from ident
3733 us User name from SSL
3735 HTTP related format codes:
3737 [http::]>h Original received request header.
3738 Usually differs from the request header sent by
3739 Squid, although most fields are often preserved.
3740 Accepts optional header field name/value filter
3741 argument using name[:[separator]element] format.
3742 [http::]>ha Received request header after adaptation and
3743 redirection (pre-cache REQMOD vectoring point).
3744 Usually differs from the request header sent by
3745 Squid, although most fields are often preserved.
3746 Optional header name argument as for >h
3747 [http::]<h Reply header. Optional header name argument
3749 [http::]>Hs HTTP status code sent to the client
3750 [http::]<Hs HTTP status code received from the next hop
3751 [http::]<bs Number of HTTP-equivalent message body bytes
3752 received from the next hop, excluding chunked
3753 transfer encoding and control messages.
3754 Generated FTP/Gopher listings are treated as
3756 [http::]mt MIME content type
3757 [http::]rm Request method (GET/POST etc)
3758 [http::]>rm Request method from client
3759 [http::]<rm Request method sent to server or peer
3760 [http::]ru Request URL from client (historic, filtered for logging)
3761 [http::]>ru Request URL from client
3762 [http::]<ru Request URL sent to server or peer
3763 [http::]rp Request URL-Path excluding hostname
3764 [http::]>rp Request URL-Path excluding hostname from client
3765 [http::]<rp Request URL-Path excluding hostname sento to server or peer
3766 [http::]rv Request protocol version
3767 [http::]>rv Request protocol version from client
3768 [http::]<rv Request protocol version sent to server or peer
3769 [http::]<st Sent reply size including HTTP headers
3770 [http::]>st Received request size including HTTP headers. In the
3771 case of chunked requests the chunked encoding metadata
3773 [http::]>sh Received HTTP request headers size
3774 [http::]<sh Sent HTTP reply headers size
3775 [http::]st Request+Reply size including HTTP headers
3776 [http::]<sH Reply high offset sent
3777 [http::]<sS Upstream object size
3778 [http::]<pt Peer response time in milliseconds. The timer starts
3779 when the last request byte is sent to the next hop
3780 and stops when the last response byte is received.
3781 [http::]<tt Total server-side time in milliseconds. The timer
3782 starts with the first connect request (or write I/O)
3783 sent to the first selected peer. The timer stops
3784 with the last I/O with the last peer.
3786 Squid handling related format codes:
3788 Ss Squid request status (TCP_MISS etc)
3789 Sh Squid hierarchy status (DEFAULT_PARENT etc)
3791 SSL-related format codes:
3793 ssl::bump_mode SslBump decision for the transaction:
3795 For CONNECT requests that initiated bumping of
3796 a connection and for any request received on
3797 an already bumped connection, Squid logs the
3798 corresponding SslBump mode ("server-first" or
3799 "client-first"). See the ssl_bump option for
3800 more information about these modes.
3802 A "none" token is logged for requests that
3803 triggered "ssl_bump" ACL evaluation matching
3804 either a "none" rule or no rules at all.
3806 In all other cases, a single dash ("-") is
3809 If ICAP is enabled, the following code becomes available (as
3810 well as ICAP log codes documented with the icap_log option):
3812 icap::tt Total ICAP processing time for the HTTP
3813 transaction. The timer ticks when ICAP
3814 ACLs are checked and when ICAP
3815 transaction is in progress.
3817 If adaptation is enabled the following three codes become available:
3819 adapt::<last_h The header of the last ICAP response or
3820 meta-information from the last eCAP
3821 transaction related to the HTTP transaction.
3822 Like <h, accepts an optional header name
3825 adapt::sum_trs Summed adaptation transaction response
3826 times recorded as a comma-separated list in
3827 the order of transaction start time. Each time
3828 value is recorded as an integer number,
3829 representing response time of one or more
3830 adaptation (ICAP or eCAP) transaction in
3831 milliseconds. When a failed transaction is
3832 being retried or repeated, its time is not
3833 logged individually but added to the
3834 replacement (next) transaction. See also:
3837 adapt::all_trs All adaptation transaction response times.
3838 Same as adaptation_strs but response times of
3839 individual transactions are never added
3840 together. Instead, all transaction response
3841 times are recorded individually.
3843 You can prefix adapt::*_trs format codes with adaptation
3844 service name in curly braces to record response time(s) specific
3845 to that service. For example: %{my_service}adapt::sum_trs
3847 If SSL is enabled, the following formating codes become available:
3849 %ssl::>cert_subject The Subject field of the received client
3850 SSL certificate or a dash ('-') if Squid has
3851 received an invalid/malformed certificate or
3852 no certificate at all. Consider encoding the
3853 logged value because Subject often has spaces.
3855 %ssl::>cert_issuer The Issuer field of the received client
3856 SSL certificate or a dash ('-') if Squid has
3857 received an invalid/malformed certificate or
3858 no certificate at all. Consider encoding the
3859 logged value because Issuer often has spaces.
3861 The default formats available (which do not need re-defining) are:
3863 logformat squid %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %[un %Sh/%<a %mt
3864 logformat common %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st %Ss:%Sh
3865 logformat combined %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
3866 logformat referrer %ts.%03tu %>a %{Referer}>h %ru
3867 logformat useragent %>a [%tl] "%{User-Agent}>h"
3869 NOTE: When the log_mime_hdrs directive is set to ON.
3870 The squid, common and combined formats have a safely encoded copy
3871 of the mime headers appended to each line within a pair of brackets.
3873 NOTE: The common and combined formats are not quite true to the Apache definition.
3874 The logs from Squid contain an extra status and hierarchy code appended.
3878 NAME: access_log cache_access_log
3880 LOC: Config.Log.accesslogs
3881 DEFAULT_IF_NONE: daemon:@DEFAULT_ACCESS_LOG@ squid
3883 Configures whether and how Squid logs HTTP and ICP transactions.
3884 If access logging is enabled, a single line is logged for every
3885 matching HTTP or ICP request. The recommended directive formats are:
3887 access_log <module>:<place> [option ...] [acl acl ...]
3888 access_log none [acl acl ...]
3890 The following directive format is accepted but may be deprecated:
3891 access_log <module>:<place> [<logformat name> [acl acl ...]]
3893 In most cases, the first ACL name must not contain the '=' character
3894 and should not be equal to an existing logformat name. You can always
3895 start with an 'all' ACL to work around those restrictions.
3897 Will log to the specified module:place using the specified format (which
3898 must be defined in a logformat directive) those entries which match
3899 ALL the acl's specified (which must be defined in acl clauses).
3900 If no acl is specified, all requests will be logged to this destination.
3902 ===== Available options for the recommended directive format =====
3904 logformat=name Names log line format (either built-in or
3905 defined by a logformat directive). Defaults
3908 buffer-size=64KB Defines approximate buffering limit for log
3909 records (see buffered_logs). Squid should not
3910 keep more than the specified size and, hence,
3911 should flush records before the buffer becomes
3912 full to avoid overflows under normal
3913 conditions (the exact flushing algorithm is
3914 module-dependent though). The on-error option
3915 controls overflow handling.
3917 on-error=die|drop Defines action on unrecoverable errors. The
3918 'drop' action ignores (i.e., does not log)
3919 affected log records. The default 'die' action
3920 kills the affected worker. The drop action
3921 support has not been tested for modules other
3924 ===== Modules Currently available =====
3926 none Do not log any requests matching these ACL.
3927 Do not specify Place or logformat name.
3929 stdio Write each log line to disk immediately at the completion of
3931 Place: the filename and path to be written.
3933 daemon Very similar to stdio. But instead of writing to disk the log
3934 line is passed to a daemon helper for asychronous handling instead.
3935 Place: varies depending on the daemon.
3937 log_file_daemon Place: the file name and path to be written.
3939 syslog To log each request via syslog facility.
3940 Place: The syslog facility and priority level for these entries.
3941 Place Format: facility.priority
3943 where facility could be any of:
3944 authpriv, daemon, local0 ... local7 or user.
3946 And priority could be any of:
3947 err, warning, notice, info, debug.
3949 udp To send each log line as text data to a UDP receiver.
3950 Place: The destination host name or IP and port.
3951 Place Format: //host:port
3953 tcp To send each log line as text data to a TCP receiver.
3954 Lines may be accumulated before sending (see buffered_logs).
3955 Place: The destination host name or IP and port.
3956 Place Format: //host:port
3959 access_log daemon:@DEFAULT_ACCESS_LOG@ squid
3965 LOC: Config.Log.icaplogs
3968 ICAP log files record ICAP transaction summaries, one line per
3971 The icap_log option format is:
3972 icap_log <filepath> [<logformat name> [acl acl ...]]
3973 icap_log none [acl acl ...]]
3975 Please see access_log option documentation for details. The two
3976 kinds of logs share the overall configuration approach and many
3979 ICAP processing of a single HTTP message or transaction may
3980 require multiple ICAP transactions. In such cases, multiple
3981 ICAP transaction log lines will correspond to a single access
3984 ICAP log uses logformat codes that make sense for an ICAP
3985 transaction. Header-related codes are applied to the HTTP header
3986 embedded in an ICAP server response, with the following caveats:
3987 For REQMOD, there is no HTTP response header unless the ICAP
3988 server performed request satisfaction. For RESPMOD, the HTTP
3989 request header is the header sent to the ICAP server. For
3990 OPTIONS, there are no HTTP headers.
3992 The following format codes are also available for ICAP logs:
3994 icap::<A ICAP server IP address. Similar to <A.
3996 icap::<service_name ICAP service name from the icap_service
3997 option in Squid configuration file.
3999 icap::ru ICAP Request-URI. Similar to ru.
4001 icap::rm ICAP request method (REQMOD, RESPMOD, or
4002 OPTIONS). Similar to existing rm.
4004 icap::>st Bytes sent to the ICAP server (TCP payload
4005 only; i.e., what Squid writes to the socket).
4007 icap::<st Bytes received from the ICAP server (TCP
4008 payload only; i.e., what Squid reads from
4011 icap::<bs Number of message body bytes received from the
4012 ICAP server. ICAP message body, if any, usually
4013 includes encapsulated HTTP message headers and
4014 possibly encapsulated HTTP message body. The
4015 HTTP body part is dechunked before its size is
4018 icap::tr Transaction response time (in
4019 milliseconds). The timer starts when
4020 the ICAP transaction is created and
4021 stops when the transaction is completed.
4024 icap::tio Transaction I/O time (in milliseconds). The
4025 timer starts when the first ICAP request
4026 byte is scheduled for sending. The timers
4027 stops when the last byte of the ICAP response
4030 icap::to Transaction outcome: ICAP_ERR* for all
4031 transaction errors, ICAP_OPT for OPTION
4032 transactions, ICAP_ECHO for 204
4033 responses, ICAP_MOD for message
4034 modification, and ICAP_SAT for request
4035 satisfaction. Similar to Ss.
4037 icap::Hs ICAP response status code. Similar to Hs.
4039 icap::>h ICAP request header(s). Similar to >h.
4041 icap::<h ICAP response header(s). Similar to <h.
4043 The default ICAP log format, which can be used without an explicit
4044 definition, is called icap_squid:
4046 logformat icap_squid %ts.%03tu %6icap::tr %>a %icap::to/%03icap::Hs %icap::<size %icap::rm %icap::ru% %un -/%icap::<A -
4048 See also: logformat, log_icap, and %adapt::<last_h
4051 NAME: logfile_daemon
4053 DEFAULT: @DEFAULT_LOGFILED@
4054 LOC: Log::TheConfig.logfile_daemon
4056 Specify the path to the logfile-writing daemon. This daemon is
4057 used to write the access and store logs, if configured.
4059 Squid sends a number of commands to the log daemon:
4060 L<data>\n - logfile data
4065 r<n>\n - set rotate count to <n>
4066 b<n>\n - 1 = buffer output, 0 = don't buffer output
4068 No responses is expected.
4074 Remove this line. Use acls with access_log directives to control access logging
4080 Remove this line. Use acls with icap_log directives to control icap logging
4083 NAME: stats_collection
4085 LOC: Config.accessList.stats_collection
4087 DEFAULT_DOC: Allow logging for all transactions.
4088 COMMENT: allow|deny acl acl...
4090 This options allows you to control which requests gets accounted
4091 in performance counters.
4093 This clause only supports fast acl types.
4094 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4097 NAME: cache_store_log
4100 LOC: Config.Log.store
4102 Logs the activities of the storage manager. Shows which
4103 objects are ejected from the cache, and which objects are
4104 saved and for how long.
4105 There are not really utilities to analyze this data, so you can safely
4106 disable it (the default).
4108 Store log uses modular logging outputs. See access_log for the list
4109 of modules supported.
4112 cache_store_log stdio:@DEFAULT_STORE_LOG@
4113 cache_store_log daemon:@DEFAULT_STORE_LOG@
4116 NAME: cache_swap_state cache_swap_log
4118 LOC: Config.Log.swap
4120 DEFAULT_DOC: Store the journal inside its cache_dir
4122 Location for the cache "swap.state" file. This index file holds
4123 the metadata of objects saved on disk. It is used to rebuild
4124 the cache during startup. Normally this file resides in each
4125 'cache_dir' directory, but you may specify an alternate
4126 pathname here. Note you must give a full filename, not just
4127 a directory. Since this is the index for the whole object
4128 list you CANNOT periodically rotate it!
4130 If %s can be used in the file name it will be replaced with a
4131 a representation of the cache_dir name where each / is replaced
4132 with '.'. This is needed to allow adding/removing cache_dir
4133 lines when cache_swap_log is being used.
4135 If have more than one 'cache_dir', and %s is not used in the name
4136 these swap logs will have names such as:
4142 The numbered extension (which is added automatically)
4143 corresponds to the order of the 'cache_dir' lines in this
4144 configuration file. If you change the order of the 'cache_dir'
4145 lines in this file, these index files will NOT correspond to
4146 the correct 'cache_dir' entry (unless you manually rename
4147 them). We recommend you do NOT use this option. It is
4148 better to keep these index files in each 'cache_dir' directory.
4151 NAME: logfile_rotate
4154 LOC: Config.Log.rotateNumber
4156 Specifies the number of logfile rotations to make when you
4157 type 'squid -k rotate'. The default is 10, which will rotate
4158 with extensions 0 through 9. Setting logfile_rotate to 0 will
4159 disable the file name rotation, but the logfiles are still closed
4160 and re-opened. This will enable you to rename the logfiles
4161 yourself just before sending the rotate signal.
4163 Note, the 'squid -k rotate' command normally sends a USR1
4164 signal to the running squid process. In certain situations
4165 (e.g. on Linux with Async I/O), USR1 is used for other
4166 purposes, so -k rotate uses another signal. It is best to get
4167 in the habit of using 'squid -k rotate' instead of 'kill -USR1
4170 Note, from Squid-3.1 this option is only a default for cache.log,
4171 that log can be rotated separately by using debug_options.
4174 NAME: emulate_httpd_log
4177 Replace this with an access_log directive using the format 'common' or 'combined'.
4180 NAME: log_ip_on_direct
4183 Remove this option from your config. To log server or peer names use %<A in the log format.
4188 DEFAULT: @DEFAULT_MIME_TABLE@
4189 LOC: Config.mimeTablePathname
4191 Path to Squid's icon configuration file.
4193 You shouldn't need to change this, but the default file contains
4194 examples and formatting information if you do.
4200 LOC: Config.onoff.log_mime_hdrs
4203 The Cache can record both the request and the response MIME
4204 headers for each HTTP transaction. The headers are encoded
4205 safely and will appear as two bracketed fields at the end of
4206 the access log (for either the native or httpd-emulated log
4207 formats). To enable this logging set log_mime_hdrs to 'on'.
4213 Replace this with an access_log directive using the format 'useragent'.
4216 NAME: referer_log referrer_log
4219 Replace this with an access_log directive using the format 'referrer'.
4224 DEFAULT: @DEFAULT_PID_FILE@
4225 LOC: Config.pidFilename
4227 A filename to write the process-id to. To disable, enter "none".
4233 Remove this option from your config. To log FQDN use %>A in the log format.
4236 NAME: client_netmask
4238 LOC: Config.Addrs.client_netmask
4240 DEFAULT_DOC: Log full client IP address
4242 A netmask for client addresses in logfiles and cachemgr output.
4243 Change this to protect the privacy of your cache clients.
4244 A netmask of 255.255.255.0 will log all IP's in that range with
4245 the last digit set to '0'.
4251 Use a regular access.log with ACL limiting it to MISS events.
4254 NAME: strip_query_terms
4256 LOC: Config.onoff.strip_query_terms
4259 By default, Squid strips query terms from requested URLs before
4260 logging. This protects your user's privacy and reduces log size.
4262 When investigating HIT/MISS or other caching behaviour you
4263 will need to disable this to see the full URL used by Squid.
4270 LOC: Config.onoff.buffered_logs
4272 Whether to write/send access_log records ASAP or accumulate them and
4273 then write/send them in larger chunks. Buffering may improve
4274 performance because it decreases the number of I/Os. However,
4275 buffering increases the delay before log records become available to
4276 the final recipient (e.g., a disk file or logging daemon) and,
4277 hence, increases the risk of log records loss.
4279 Note that even when buffered_logs are off, Squid may have to buffer
4280 records if it cannot write/send them immediately due to pending I/Os
4281 (e.g., the I/O writing the previous log record) or connectivity loss.
4283 Currently honored by 'daemon' and 'tcp' access_log modules only.
4286 NAME: netdb_filename
4288 DEFAULT: stdio:@DEFAULT_NETDB_FILE@
4289 LOC: Config.netdbFilename
4292 Where Squid stores it's netdb journal.
4293 When enabled this journal preserves netdb state between restarts.
4295 To disable, enter "none".
4299 OPTIONS FOR TROUBLESHOOTING
4300 -----------------------------------------------------------------------------
4305 DEFAULT_IF_NONE: @DEFAULT_CACHE_LOG@
4306 LOC: Debug::cache_log
4308 Squid administrative logging file.
4310 This is where general information about Squid behavior goes. You can
4311 increase the amount of data logged to this file and how often it is
4312 rotated with "debug_options"
4318 DEFAULT_DOC: Log all critical and important messages.
4319 LOC: Debug::debugOptions
4321 Logging options are set as section,level where each source file
4322 is assigned a unique section. Lower levels result in less
4323 output, Full debugging (level 9) can result in a very large
4324 log file, so be careful.
4326 The magic word "ALL" sets debugging levels for all sections.
4327 The default is to run with "ALL,1" to record important warnings.
4329 The rotate=N option can be used to keep more or less of these logs
4330 than would otherwise be kept by logfile_rotate.
4331 For most uses a single log should be enough to monitor current
4332 events affecting Squid.
4337 LOC: Config.coredump_dir
4338 DEFAULT_IF_NONE: none
4339 DEFAULT_DOC: Use the directory from where Squid was started.
4341 By default Squid leaves core files in the directory from where
4342 it was started. If you set 'coredump_dir' to a directory
4343 that exists, Squid will chdir() to that directory at startup
4344 and coredump files will be left there.
4348 # Leave coredumps in the first cache dir
4349 coredump_dir @DEFAULT_SWAP_DIR@
4355 OPTIONS FOR FTP GATEWAYING
4356 -----------------------------------------------------------------------------
4362 LOC: Config.Ftp.anon_user
4364 If you want the anonymous login password to be more informative
4365 (and enable the use of picky FTP servers), set this to something
4366 reasonable for your domain, like wwwuser@somewhere.net
4368 The reason why this is domainless by default is the
4369 request can be made on the behalf of a user in any domain,
4370 depending on how the cache is used.
4371 Some FTP server also validate the email address is valid
4372 (for example perl.com).
4378 LOC: Config.Ftp.passive
4380 If your firewall does not allow Squid to use passive
4381 connections, turn off this option.
4383 Use of ftp_epsv_all option requires this to be ON.
4389 LOC: Config.Ftp.epsv_all
4391 FTP Protocol extensions permit the use of a special "EPSV ALL" command.
4393 NATs may be able to put the connection on a "fast path" through the
4394 translator, as the EPRT command will never be used and therefore,
4395 translation of the data portion of the segments will never be needed.
4397 When a client only expects to do two-way FTP transfers this may be
4399 If squid finds that it must do a three-way FTP transfer after issuing
4400 an EPSV ALL command, the FTP session will fail.
4402 If you have any doubts about this option do not use it.
4403 Squid will nicely attempt all other connection methods.
4405 Requires ftp_passive to be ON (default) for any effect.
4411 LOC: Config.Ftp.epsv
4413 FTP Protocol extensions permit the use of a special "EPSV" command.
4415 NATs may be able to put the connection on a "fast path" through the
4416 translator using EPSV, as the EPRT command will never be used
4417 and therefore, translation of the data portion of the segments
4418 will never be needed.
4420 Turning this OFF will prevent EPSV being attempted.
4421 WARNING: Doing so will convert Squid back to the old behavior with all
4422 the related problems with external NAT devices/layers.
4424 Requires ftp_passive to be ON (default) for any effect.
4430 LOC: Config.Ftp.eprt
4432 FTP Protocol extensions permit the use of a special "EPRT" command.
4434 This extension provides a protocol neutral alternative to the
4435 IPv4-only PORT command. When supported it enables active FTP data
4436 channels over IPv6 and efficient NAT handling.
4438 Turning this OFF will prevent EPRT being attempted and will skip
4439 straight to using PORT for IPv4 servers.
4441 Some devices are known to not handle this extension correctly and
4442 may result in crashes. Devices which suport EPRT enough to fail
4443 cleanly will result in Squid attempting PORT anyway. This directive
4444 should only be disabled when EPRT results in device failures.
4446 WARNING: Doing so will convert Squid back to the old behavior with all
4447 the related problems with external NAT devices/layers and IPv4-only FTP.
4450 NAME: ftp_sanitycheck
4453 LOC: Config.Ftp.sanitycheck
4455 For security and data integrity reasons Squid by default performs
4456 sanity checks of the addresses of FTP data connections ensure the
4457 data connection is to the requested server. If you need to allow
4458 FTP connections to servers using another IP address for the data
4459 connection turn this off.
4462 NAME: ftp_telnet_protocol
4465 LOC: Config.Ftp.telnet
4467 The FTP protocol is officially defined to use the telnet protocol
4468 as transport channel for the control connection. However, many
4469 implementations are broken and does not respect this aspect of
4472 If you have trouble accessing files with ASCII code 255 in the
4473 path or similar problems involving this ASCII code you can
4474 try setting this directive to off. If that helps, report to the
4475 operator of the FTP server in question that their FTP server
4476 is broken and does not follow the FTP standard.
4480 OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
4481 -----------------------------------------------------------------------------
4486 DEFAULT: @DEFAULT_DISKD@
4487 LOC: Config.Program.diskd
4489 Specify the location of the diskd executable.
4490 Note this is only useful if you have compiled in
4491 diskd as one of the store io modules.
4494 NAME: unlinkd_program
4497 DEFAULT: @DEFAULT_UNLINKD@
4498 LOC: Config.Program.unlinkd
4500 Specify the location of the executable for file deletion process.
4503 NAME: pinger_program
4505 DEFAULT: @DEFAULT_PINGER@
4506 LOC: Config.pinger.program
4509 Specify the location of the executable for the pinger process.
4515 LOC: Config.pinger.enable
4518 Control whether the pinger is active at run-time.
4519 Enables turning ICMP pinger on and off with a simple
4520 squid -k reconfigure.
4525 OPTIONS FOR URL REWRITING
4526 -----------------------------------------------------------------------------
4529 NAME: url_rewrite_program redirect_program
4531 LOC: Config.Program.redirect
4534 Specify the location of the executable URL rewriter to use.
4535 Since they can perform almost any function there isn't one included.
4537 For each requested URL, the rewriter will receive on line with the format
4539 [channel-ID <SP>] URL <SP> client_ip "/" fqdn <SP> user <SP> method [<SP> kv-pairs]<NL>
4542 After processing the request the helper must reply using the following format:
4544 [channel-ID <SP>] result [<SP> kv-pairs]
4546 The result code can be:
4548 OK status=30N url="..."
4549 Redirect the URL to the one supplied in 'url='.
4550 'status=' is optional and contains the status code to send
4551 the client in Squids HTTP response. It must be one of the
4552 HTTP redirect status codes: 301, 302, 303, 307, 308.
4553 When no status is given Squid will use 302.
4555 OK rewrite-url="..."
4556 Rewrite the URL to the one supplied in 'rewrite-url='.
4557 The new URL is fetched directly by Squid and returned to
4558 the client as the response to its request.
4561 Do not change the URL.
4564 An internal error occurred in the helper, preventing
4565 a result being identified.
4568 In the future, the interface protocol will be extended with
4569 key=value pairs ("kv-pairs" shown above). Helper programs
4570 should be prepared to receive and possibly ignore additional
4571 whitespace-separated tokens on each input line.
4573 When using the concurrency= option the protocol is changed by
4574 introducing a query channel tag in front of the request/response.
4575 The query channel tag is a number between 0 and concurrency-1.
4576 This value must be echoed back unchanged to Squid as the first part
4577 of the response relating to its request.
4579 WARNING: URL re-writing ability should be avoided whenever possible.
4580 Use the URL redirect form of response instead.
4582 Re-write creates a difference in the state held by the client
4583 and server. Possibly causing confusion when the server response
4584 contains snippets of its view state. Embeded URLs, response
4585 and content Location headers, etc. are not re-written by this
4588 By default, a URL rewriter is not used.
4591 NAME: url_rewrite_children redirect_children
4592 TYPE: HelperChildConfig
4593 DEFAULT: 20 startup=0 idle=1 concurrency=0
4594 LOC: Config.redirectChildren
4596 The maximum number of redirector processes to spawn. If you limit
4597 it too few Squid will have to wait for them to process a backlog of
4598 URLs, slowing it down. If you allow too many they will use RAM
4599 and other system resources noticably.
4601 The startup= and idle= options allow some measure of skew in your
4606 Sets a minimum of how many processes are to be spawned when Squid
4607 starts or reconfigures. When set to zero the first request will
4608 cause spawning of the first child process to handle it.
4610 Starting too few will cause an initial slowdown in traffic as Squid
4611 attempts to simultaneously spawn enough processes to cope.
4615 Sets a minimum of how many processes Squid is to try and keep available
4616 at all times. When traffic begins to rise above what the existing
4617 processes can handle this many more will be spawned up to the maximum
4618 configured. A minimum setting of 1 is required.
4622 The number of requests each redirector helper can handle in
4623 parallel. Defaults to 0 which indicates the redirector
4624 is a old-style single threaded redirector.
4626 When this directive is set to a value >= 1 then the protocol
4627 used to communicate with the helper is modified to include
4628 an ID in front of the request/response. The ID from the request
4629 must be echoed back with the response to that request.
4632 NAME: url_rewrite_host_header redirect_rewrites_host_header
4635 LOC: Config.onoff.redir_rewrites_host
4637 To preserve same-origin security policies in browsers and
4638 prevent Host: header forgery by redirectors Squid rewrites
4639 any Host: header in redirected requests.
4641 If you are running an accelerator this may not be a wanted
4642 effect of a redirector. This directive enables you disable
4643 Host: alteration in reverse-proxy traffic.
4645 WARNING: Entries are cached on the result of the URL rewriting
4646 process, so be careful if you have domain-virtual hosts.
4648 WARNING: Squid and other software verifies the URL and Host
4649 are matching, so be careful not to relay through other proxies
4650 or inspecting firewalls with this disabled.
4653 NAME: url_rewrite_access redirector_access
4656 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
4657 LOC: Config.accessList.redirector
4659 If defined, this access list specifies which requests are
4660 sent to the redirector processes.
4662 This clause supports both fast and slow acl types.
4663 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4666 NAME: url_rewrite_bypass redirector_bypass
4668 LOC: Config.onoff.redirector_bypass
4671 When this is 'on', a request will not go through the
4672 redirector if all the helpers are busy. If this is 'off'
4673 and the redirector queue grows too large, Squid will exit
4674 with a FATAL error and ask you to increase the number of
4675 redirectors. You should only enable this if the redirectors
4676 are not critical to your caching system. If you use
4677 redirectors for access control, and you enable this option,
4678 users may have access to pages they should not
4679 be allowed to request.
4683 OPTIONS FOR STORE ID
4684 -----------------------------------------------------------------------------
4687 NAME: store_id_program storeurl_rewrite_program
4689 LOC: Config.Program.store_id
4692 Specify the location of the executable StoreID helper to use.
4693 Since they can perform almost any function there isn't one included.
4695 For each requested URL, the helper will receive one line with the format
4697 [channel-ID <SP>] URL <SP> client_ip "/" fqdn <SP> user <SP> method [<SP> kv-pairs]<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:
4707 Use the StoreID supplied in 'store-id='.
4710 The default is to use HTTP request URL as the store ID.
4713 An internal error occured in the helper, preventing
4714 a result being identified.
4717 Helper programs should be prepared to receive and possibly ignore additional
4718 kv-pairs with keys they do not support.
4720 When using the concurrency= option the protocol is changed by
4721 introducing a query channel tag in front of the request/response.
4722 The query channel tag is a number between 0 and concurrency-1.
4723 This value must be echoed back unchanged to Squid as the first part
4724 of the response relating to its request.
4726 NOTE: when using StoreID refresh_pattern will apply to the StoreID
4727 returned from the helper and not the URL.
4729 WARNING: Wrong StoreID value returned by a careless helper may result
4730 in the wrong cached response returned to the user.
4732 By default, a StoreID helper is not used.
4735 NAME: store_id_children storeurl_rewrite_children
4736 TYPE: HelperChildConfig
4737 DEFAULT: 20 startup=0 idle=1 concurrency=0
4738 LOC: Config.storeIdChildren
4740 The maximum number of StoreID helper processes to spawn. If you limit
4741 it too few Squid will have to wait for them to process a backlog of
4742 requests, slowing it down. If you allow too many they will use RAM
4743 and other system resources noticably.
4745 The startup= and idle= options allow some measure of skew in your
4750 Sets a minimum of how many processes are to be spawned when Squid
4751 starts or reconfigures. When set to zero the first request will
4752 cause spawning of the first child process to handle it.
4754 Starting too few will cause an initial slowdown in traffic as Squid
4755 attempts to simultaneously spawn enough processes to cope.
4759 Sets a minimum of how many processes Squid is to try and keep available
4760 at all times. When traffic begins to rise above what the existing
4761 processes can handle this many more will be spawned up to the maximum
4762 configured. A minimum setting of 1 is required.
4766 The number of requests each storeID helper can handle in
4767 parallel. Defaults to 0 which indicates the helper
4768 is a old-style single threaded program.
4770 When this directive is set to a value >= 1 then the protocol
4771 used to communicate with the helper is modified to include
4772 an ID in front of the request/response. The ID from the request
4773 must be echoed back with the response to that request.
4776 NAME: store_id_access storeurl_rewrite_access
4779 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
4780 LOC: Config.accessList.store_id
4782 If defined, this access list specifies which requests are
4783 sent to the StoreID processes. By default all requests
4786 This clause supports both fast and slow acl types.
4787 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4790 NAME: store_id_bypass storeurl_rewrite_bypass
4792 LOC: Config.onoff.store_id_bypass
4795 When this is 'on', a request will not go through the
4796 helper if all helpers are busy. If this is 'off'
4797 and the helper queue grows too large, Squid will exit
4798 with a FATAL error and ask you to increase the number of
4799 helpers. You should only enable this if the helperss
4800 are not critical to your caching system. If you use
4801 helpers for critical caching components, and you enable this
4802 option, users may not get objects from cache.
4806 OPTIONS FOR TUNING THE CACHE
4807 -----------------------------------------------------------------------------
4810 NAME: cache no_cache
4813 DEFAULT_DOC: Allow caching, unless rules exist in squid.conf.
4814 LOC: Config.accessList.noCache
4816 A list of ACL elements which, if matched and denied, cause the request to
4817 not be satisfied from the cache and the reply to not be cached.
4818 In other words, use this to force certain objects to never be cached.
4820 You must use the words 'allow' or 'deny' to indicate whether items
4821 matching the ACL should be allowed or denied into the cache.
4823 This clause supports both fast and slow acl types.
4824 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4830 LOC: Config.maxStale
4833 This option puts an upper limit on how stale content Squid
4834 will serve from the cache if cache validation fails.
4835 Can be overriden by the refresh_pattern max-stale option.
4838 NAME: refresh_pattern
4839 TYPE: refreshpattern
4843 usage: refresh_pattern [-i] regex min percent max [options]
4845 By default, regular expressions are CASE-SENSITIVE. To make
4846 them case-insensitive, use the -i option.
4848 'Min' is the time (in minutes) an object without an explicit
4849 expiry time should be considered fresh. The recommended
4850 value is 0, any higher values may cause dynamic applications
4851 to be erroneously cached unless the application designer
4852 has taken the appropriate actions.
4854 'Percent' is a percentage of the objects age (time since last
4855 modification age) an object without explicit expiry time
4856 will be considered fresh.
4858 'Max' is an upper limit on how long objects without an explicit
4859 expiry time will be considered fresh.
4861 options: override-expire
4866 ignore-must-revalidate
4873 override-expire enforces min age even if the server
4874 sent an explicit expiry time (e.g., with the
4875 Expires: header or Cache-Control: max-age). Doing this
4876 VIOLATES the HTTP standard. Enabling this feature
4877 could make you liable for problems which it causes.
4879 Note: override-expire does not enforce staleness - it only extends
4880 freshness / min. If the server returns a Expires time which
4881 is longer than your max time, Squid will still consider
4882 the object fresh for that period of time.
4884 override-lastmod enforces min age even on objects
4885 that were modified recently.
4887 reload-into-ims changes a client no-cache or ``reload''
4888 request for a cached entry into a conditional request using
4889 If-Modified-Since and/or If-None-Match headers, provided the
4890 cached entry has a Last-Modified and/or a strong ETag header.
4891 Doing this VIOLATES the HTTP standard. Enabling this feature
4892 could make you liable for problems which it causes.
4894 ignore-reload ignores a client no-cache or ``reload''
4895 header. Doing this VIOLATES the HTTP standard. Enabling
4896 this feature could make you liable for problems which
4899 ignore-no-store ignores any ``Cache-control: no-store''
4900 headers received from a server. Doing this VIOLATES
4901 the HTTP standard. Enabling this feature could make you
4902 liable for problems which it causes.
4904 ignore-must-revalidate ignores any ``Cache-Control: must-revalidate``
4905 headers received from a server. Doing this VIOLATES
4906 the HTTP standard. Enabling this feature could make you
4907 liable for problems which it causes.
4909 ignore-private ignores any ``Cache-control: private''
4910 headers received from a server. Doing this VIOLATES
4911 the HTTP standard. Enabling this feature could make you
4912 liable for problems which it causes.
4914 ignore-auth caches responses to requests with authorization,
4915 as if the originserver had sent ``Cache-control: public''
4916 in the response header. Doing this VIOLATES the HTTP standard.
4917 Enabling this feature could make you liable for problems which
4920 refresh-ims causes squid to contact the origin server
4921 when a client issues an If-Modified-Since request. This
4922 ensures that the client will receive an updated version
4923 if one is available.
4925 store-stale stores responses even if they don't have explicit
4926 freshness or a validator (i.e., Last-Modified or an ETag)
4927 present, or if they're already stale. By default, Squid will
4928 not cache such responses because they usually can't be
4929 reused. Note that such responses will be stale by default.
4931 max-stale=NN provide a maximum staleness factor. Squid won't
4932 serve objects more stale than this even if it failed to
4933 validate the object. Default: use the max_stale global limit.
4935 Basically a cached object is:
4937 FRESH if expires < now, else STALE
4939 FRESH if lm-factor < percent, else STALE
4943 The refresh_pattern lines are checked in the order listed here.
4944 The first entry which matches is used. If none of the entries
4945 match the default will be used.
4947 Note, you must uncomment all the default lines if you want
4948 to change one. The default setting is only active if none is
4954 # Add any of your own refresh_pattern entries above these.
4956 refresh_pattern ^ftp: 1440 20% 10080
4957 refresh_pattern ^gopher: 1440 0% 1440
4958 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0
4959 refresh_pattern . 0 20% 4320
4963 NAME: quick_abort_min
4967 LOC: Config.quickAbort.min
4970 NAME: quick_abort_max
4974 LOC: Config.quickAbort.max
4977 NAME: quick_abort_pct
4981 LOC: Config.quickAbort.pct
4983 The cache by default continues downloading aborted requests
4984 which are almost completed (less than 16 KB remaining). This
4985 may be undesirable on slow (e.g. SLIP) links and/or very busy
4986 caches. Impatient users may tie up file descriptors and
4987 bandwidth by repeatedly requesting and immediately aborting
4990 When the user aborts a request, Squid will check the
4991 quick_abort values to the amount of data transfered until
4994 If the transfer has less than 'quick_abort_min' KB remaining,
4995 it will finish the retrieval.
4997 If the transfer has more than 'quick_abort_max' KB remaining,
4998 it will abort the retrieval.
5000 If more than 'quick_abort_pct' of the transfer has completed,
5001 it will finish the retrieval.
5003 If you do not want any retrieval to continue after the client
5004 has aborted, set both 'quick_abort_min' and 'quick_abort_max'
5007 If you want retrievals to always continue if they are being
5008 cached set 'quick_abort_min' to '-1 KB'.
5011 NAME: read_ahead_gap
5012 COMMENT: buffer-size
5014 LOC: Config.readAheadGap
5017 The amount of data the cache will buffer ahead of what has been
5018 sent to the client when retrieving an object from another server.
5022 IFDEF: USE_HTTP_VIOLATIONS
5025 LOC: Config.negativeTtl
5028 Set the Default Time-to-Live (TTL) for failed requests.
5029 Certain types of failures (such as "connection refused" and
5030 "404 Not Found") are able to be negatively-cached for a short time.
5031 Modern web servers should provide Expires: header, however if they
5032 do not this can provide a minimum TTL.
5033 The default is not to cache errors with unknown expiry details.
5035 Note that this is different from negative caching of DNS lookups.
5037 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5038 this feature could make you liable for problems which it
5042 NAME: positive_dns_ttl
5045 LOC: Config.positiveDnsTtl
5048 Upper limit on how long Squid will cache positive DNS responses.
5049 Default is 6 hours (360 minutes). This directive must be set
5050 larger than negative_dns_ttl.
5053 NAME: negative_dns_ttl
5056 LOC: Config.negativeDnsTtl
5059 Time-to-Live (TTL) for negative caching of failed DNS lookups.
5060 This also sets the lower cache limit on positive lookups.
5061 Minimum value is 1 second, and it is not recommendable to go
5062 much below 10 seconds.
5065 NAME: range_offset_limit
5066 COMMENT: size [acl acl...]
5068 LOC: Config.rangeOffsetLimit
5071 usage: (size) [units] [[!]aclname]
5073 Sets an upper limit on how far (number of bytes) into the file
5074 a Range request may be to cause Squid to prefetch the whole file.
5075 If beyond this limit, Squid forwards the Range request as it is and
5076 the result is NOT cached.
5078 This is to stop a far ahead range request (lets say start at 17MB)
5079 from making Squid fetch the whole object up to that point before
5080 sending anything to the client.
5082 Multiple range_offset_limit lines may be specified, and they will
5083 be searched from top to bottom on each request until a match is found.
5084 The first match found will be used. If no line matches a request, the
5085 default limit of 0 bytes will be used.
5087 'size' is the limit specified as a number of units.
5089 'units' specifies whether to use bytes, KB, MB, etc.
5090 If no units are specified bytes are assumed.
5092 A size of 0 causes Squid to never fetch more than the
5093 client requested. (default)
5095 A size of 'none' causes Squid to always fetch the object from the
5096 beginning so it may cache the result. (2.0 style)
5098 'aclname' is the name of a defined ACL.
5100 NP: Using 'none' as the byte value here will override any quick_abort settings
5101 that may otherwise apply to the range request. The range request will
5102 be fully fetched from start to finish regardless of the client
5103 actions. This affects bandwidth usage.
5106 NAME: minimum_expiry_time
5109 LOC: Config.minimum_expiry_time
5112 The minimum caching time according to (Expires - Date)
5113 headers Squid honors if the object can't be revalidated.
5114 The default is 60 seconds.
5116 In reverse proxy environments it might be desirable to honor
5117 shorter object lifetimes. It is most likely better to make
5118 your server return a meaningful Last-Modified header however.
5120 In ESI environments where page fragments often have short
5121 lifetimes, this will often be best set to 0.
5124 NAME: store_avg_object_size
5128 LOC: Config.Store.avgObjectSize
5130 Average object size, used to estimate number of objects your
5131 cache can hold. The default is 13 KB.
5133 This is used to pre-seed the cache index memory allocation to
5134 reduce expensive reallocate operations while handling clients
5135 traffic. Too-large values may result in memory allocation during
5136 peak traffic, too-small values will result in wasted memory.
5138 Check the cache manager 'info' report metrics for the real
5139 object sizes seen by your Squid before tuning this.
5142 NAME: store_objects_per_bucket
5145 LOC: Config.Store.objectsPerBucket
5147 Target number of objects per bucket in the store hash table.
5148 Lowering this value increases the total number of buckets and
5149 also the storage maintenance rate. The default is 20.
5154 -----------------------------------------------------------------------------
5157 NAME: request_header_max_size
5161 LOC: Config.maxRequestHeaderSize
5163 This specifies the maximum size for HTTP headers in a request.
5164 Request headers are usually relatively small (about 512 bytes).
5165 Placing a limit on the request header size will catch certain
5166 bugs (for example with persistent connections) and possibly
5167 buffer-overflow or denial-of-service attacks.
5170 NAME: reply_header_max_size
5174 LOC: Config.maxReplyHeaderSize
5176 This specifies the maximum size for HTTP headers in a reply.
5177 Reply headers are usually relatively small (about 512 bytes).
5178 Placing a limit on the reply header size will catch certain
5179 bugs (for example with persistent connections) and possibly
5180 buffer-overflow or denial-of-service attacks.
5183 NAME: request_body_max_size
5187 DEFAULT_DOC: No limit.
5188 LOC: Config.maxRequestBodySize
5190 This specifies the maximum size for an HTTP request body.
5191 In other words, the maximum size of a PUT/POST request.
5192 A user who attempts to send a request with a body larger
5193 than this limit receives an "Invalid Request" error message.
5194 If you set this parameter to a zero (the default), there will
5195 be no limit imposed.
5197 See also client_request_buffer_max_size for an alternative
5198 limitation on client uploads which can be configured.
5201 NAME: client_request_buffer_max_size
5205 LOC: Config.maxRequestBufferSize
5207 This specifies the maximum buffer size of a client request.
5208 It prevents squid eating too much memory when somebody uploads
5212 NAME: chunked_request_body_max_size
5216 LOC: Config.maxChunkedRequestBodySize
5218 A broken or confused HTTP/1.1 client may send a chunked HTTP
5219 request to Squid. Squid does not have full support for that
5220 feature yet. To cope with such requests, Squid buffers the
5221 entire request and then dechunks request body to create a
5222 plain HTTP/1.0 request with a known content length. The plain
5223 request is then used by the rest of Squid code as usual.
5225 The option value specifies the maximum size of the buffer used
5226 to hold the request before the conversion. If the chunked
5227 request size exceeds the specified limit, the conversion
5228 fails, and the client receives an "unsupported request" error,
5229 as if dechunking was disabled.
5231 Dechunking is enabled by default. To disable conversion of
5232 chunked requests, set the maximum to zero.
5234 Request dechunking feature and this option in particular are a
5235 temporary hack. When chunking requests and responses are fully
5236 supported, there will be no need to buffer a chunked request.
5240 IFDEF: USE_HTTP_VIOLATIONS
5243 DEFAULT_DOC: Obey RFC 2616.
5244 LOC: Config.accessList.brokenPosts
5246 A list of ACL elements which, if matched, causes Squid to send
5247 an extra CRLF pair after the body of a PUT/POST request.
5249 Some HTTP servers has broken implementations of PUT/POST,
5250 and rely on an extra CRLF pair sent by some WWW clients.
5252 Quote from RFC2616 section 4.1 on this matter:
5254 Note: certain buggy HTTP/1.0 client implementations generate an
5255 extra CRLF's after a POST request. To restate what is explicitly
5256 forbidden by the BNF, an HTTP/1.1 client must not preface or follow
5257 a request with an extra CRLF.
5259 This clause only supports fast acl types.
5260 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5263 acl buggy_server url_regex ^http://....
5264 broken_posts allow buggy_server
5267 NAME: adaptation_uses_indirect_client icap_uses_indirect_client
5270 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_ADAPTATION
5272 LOC: Adaptation::Config::use_indirect_client
5274 Controls whether the indirect client IP address (instead of the direct
5275 client IP address) is passed to adaptation services.
5277 See also: follow_x_forwarded_for adaptation_send_client_ip
5281 IFDEF: USE_HTTP_VIOLATIONS
5285 LOC: Config.onoff.via
5287 If set (default), Squid will include a Via header in requests and
5288 replies as required by RFC2616.
5294 LOC: Config.onoff.ie_refresh
5297 Microsoft Internet Explorer up until version 5.5 Service
5298 Pack 1 has an issue with transparent proxies, wherein it
5299 is impossible to force a refresh. Turning this on provides
5300 a partial fix to the problem, by causing all IMS-REFRESH
5301 requests from older IE versions to check the origin server
5302 for fresh content. This reduces hit ratio by some amount
5303 (~10% in my experience), but allows users to actually get
5304 fresh content when they want it. Note because Squid
5305 cannot tell if the user is using 5.5 or 5.5SP1, the behavior
5306 of 5.5 is unchanged from old versions of Squid (i.e. a
5307 forced refresh is impossible). Newer versions of IE will,
5308 hopefully, continue to have the new behavior and will be
5309 handled based on that assumption. This option defaults to
5310 the old Squid behavior, which is better for hit ratios but
5311 worse for clients using IE, if they need to be able to
5312 force fresh content.
5315 NAME: vary_ignore_expire
5318 LOC: Config.onoff.vary_ignore_expire
5321 Many HTTP servers supporting Vary gives such objects
5322 immediate expiry time with no cache-control header
5323 when requested by a HTTP/1.0 client. This option
5324 enables Squid to ignore such expiry times until
5325 HTTP/1.1 is fully implemented.
5327 WARNING: If turned on this may eventually cause some
5328 varying objects not intended for caching to get cached.
5331 NAME: request_entities
5333 LOC: Config.onoff.request_entities
5336 Squid defaults to deny GET and HEAD requests with request entities,
5337 as the meaning of such requests are undefined in the HTTP standard
5338 even if not explicitly forbidden.
5340 Set this directive to on if you have clients which insists
5341 on sending request entities in GET or HEAD requests. But be warned
5342 that there is server software (both proxies and web servers) which
5343 can fail to properly process this kind of request which may make you
5344 vulnerable to cache pollution attacks if enabled.
5347 NAME: request_header_access
5348 IFDEF: USE_HTTP_VIOLATIONS
5349 TYPE: http_header_access
5350 LOC: Config.request_header_access
5352 DEFAULT_DOC: No limits.
5354 Usage: request_header_access header_name allow|deny [!]aclname ...
5356 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5357 this feature could make you liable for problems which it
5360 This option replaces the old 'anonymize_headers' and the
5361 older 'http_anonymizer' option with something that is much
5362 more configurable. A list of ACLs for each header name allows
5363 removal of specific header fields under specific conditions.
5365 This option only applies to outgoing HTTP request headers (i.e.,
5366 headers sent by Squid to the next HTTP hop such as a cache peer
5367 or an origin server). The option has no effect during cache hit
5368 detection. The equivalent adaptation vectoring point in ICAP
5369 terminology is post-cache REQMOD.
5371 The option is applied to individual outgoing request header
5372 fields. For each request header field F, Squid uses the first
5373 qualifying sets of request_header_access rules:
5375 1. Rules with header_name equal to F's name.
5376 2. Rules with header_name 'Other', provided F's name is not
5377 on the hard-coded list of commonly used HTTP header names.
5378 3. Rules with header_name 'All'.
5380 Within that qualifying rule set, rule ACLs are checked as usual.
5381 If ACLs of an "allow" rule match, the header field is allowed to
5382 go through as is. If ACLs of a "deny" rule match, the header is
5383 removed and request_header_replace is then checked to identify
5384 if the removed header has a replacement. If no rules within the
5385 set have matching ACLs, the header field is left as is.
5387 For example, to achieve the same behavior as the old
5388 'http_anonymizer standard' option, you should use:
5390 request_header_access From deny all
5391 request_header_access Referer deny all
5392 request_header_access User-Agent deny all
5394 Or, to reproduce the old 'http_anonymizer paranoid' feature
5397 request_header_access Authorization allow all
5398 request_header_access Proxy-Authorization allow all
5399 request_header_access Cache-Control allow all
5400 request_header_access Content-Length allow all
5401 request_header_access Content-Type allow all
5402 request_header_access Date allow all
5403 request_header_access Host allow all
5404 request_header_access If-Modified-Since allow all
5405 request_header_access Pragma allow all
5406 request_header_access Accept allow all
5407 request_header_access Accept-Charset allow all
5408 request_header_access Accept-Encoding allow all
5409 request_header_access Accept-Language allow all
5410 request_header_access Connection allow all
5411 request_header_access All deny all
5413 HTTP reply headers are controlled with the reply_header_access directive.
5415 By default, all headers are allowed (no anonymizing is performed).
5418 NAME: reply_header_access
5419 IFDEF: USE_HTTP_VIOLATIONS
5420 TYPE: http_header_access
5421 LOC: Config.reply_header_access
5423 DEFAULT_DOC: No limits.
5425 Usage: reply_header_access header_name allow|deny [!]aclname ...
5427 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5428 this feature could make you liable for problems which it
5431 This option only applies to reply headers, i.e., from the
5432 server to the client.
5434 This is the same as request_header_access, but in the other
5435 direction. Please see request_header_access for detailed
5438 For example, to achieve the same behavior as the old
5439 'http_anonymizer standard' option, you should use:
5441 reply_header_access Server deny all
5442 reply_header_access WWW-Authenticate deny all
5443 reply_header_access Link deny all
5445 Or, to reproduce the old 'http_anonymizer paranoid' feature
5448 reply_header_access Allow allow all
5449 reply_header_access WWW-Authenticate allow all
5450 reply_header_access Proxy-Authenticate allow all
5451 reply_header_access Cache-Control allow all
5452 reply_header_access Content-Encoding allow all
5453 reply_header_access Content-Length allow all
5454 reply_header_access Content-Type allow all
5455 reply_header_access Date allow all
5456 reply_header_access Expires allow all
5457 reply_header_access Last-Modified allow all
5458 reply_header_access Location allow all
5459 reply_header_access Pragma allow all
5460 reply_header_access Content-Language allow all
5461 reply_header_access Retry-After allow all
5462 reply_header_access Title allow all
5463 reply_header_access Content-Disposition allow all
5464 reply_header_access Connection allow all
5465 reply_header_access All deny all
5467 HTTP request headers are controlled with the request_header_access directive.
5469 By default, all headers are allowed (no anonymizing is
5473 NAME: request_header_replace header_replace
5474 IFDEF: USE_HTTP_VIOLATIONS
5475 TYPE: http_header_replace
5476 LOC: Config.request_header_access
5479 Usage: request_header_replace header_name message
5480 Example: request_header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
5482 This option allows you to change the contents of headers
5483 denied with request_header_access above, by replacing them
5484 with some fixed string.
5486 This only applies to request headers, not reply headers.
5488 By default, headers are removed if denied.
5491 NAME: reply_header_replace
5492 IFDEF: USE_HTTP_VIOLATIONS
5493 TYPE: http_header_replace
5494 LOC: Config.reply_header_access
5497 Usage: reply_header_replace header_name message
5498 Example: reply_header_replace Server Foo/1.0
5500 This option allows you to change the contents of headers
5501 denied with reply_header_access above, by replacing them
5502 with some fixed string.
5504 This only applies to reply headers, not request headers.
5506 By default, headers are removed if denied.
5509 NAME: request_header_add
5510 TYPE: HeaderWithAclList
5511 LOC: Config.request_header_add
5514 Usage: request_header_add field-name field-value acl1 [acl2] ...
5515 Example: request_header_add X-Client-CA "CA=%ssl::>cert_issuer" all
5517 This option adds header fields to outgoing HTTP requests (i.e.,
5518 request headers sent by Squid to the next HTTP hop such as a
5519 cache peer or an origin server). The option has no effect during
5520 cache hit detection. The equivalent adaptation vectoring point
5521 in ICAP terminology is post-cache REQMOD.
5523 Field-name is a token specifying an HTTP header name. If a
5524 standard HTTP header name is used, Squid does not check whether
5525 the new header conflicts with any existing headers or violates
5526 HTTP rules. If the request to be modified already contains a
5527 field with the same name, the old field is preserved but the
5528 header field values are not merged.
5530 Field-value is either a token or a quoted string. If quoted
5531 string format is used, then the surrounding quotes are removed
5532 while escape sequences and %macros are processed.
5534 In theory, all of the logformat codes can be used as %macros.
5535 However, unlike logging (which happens at the very end of
5536 transaction lifetime), the transaction may not yet have enough
5537 information to expand a macro when the new header value is needed.
5538 And some information may already be available to Squid but not yet
5539 committed where the macro expansion code can access it (report
5540 such instances!). The macro will be expanded into a single dash
5541 ('-') in such cases. Not all macros have been tested.
5543 One or more Squid ACLs may be specified to restrict header
5544 injection to matching requests. As always in squid.conf, all
5545 ACLs in an option ACL list must be satisfied for the insertion
5546 to happen. The request_header_add option supports fast ACLs
5555 This option used to log custom information about the master
5556 transaction. For example, an admin may configure Squid to log
5557 which "user group" the transaction belongs to, where "user group"
5558 will be determined based on a set of ACLs and not [just]
5559 authentication information.
5560 Values of key/value pairs can be logged using %{key}note macros:
5562 note key value acl ...
5563 logformat myFormat ... %{key}note ...
5566 NAME: relaxed_header_parser
5567 COMMENT: on|off|warn
5569 LOC: Config.onoff.relaxed_header_parser
5572 In the default "on" setting Squid accepts certain forms
5573 of non-compliant HTTP messages where it is unambiguous
5574 what the sending application intended even if the message
5575 is not correctly formatted. The messages is then normalized
5576 to the correct form when forwarded by Squid.
5578 If set to "warn" then a warning will be emitted in cache.log
5579 each time such HTTP error is encountered.
5581 If set to "off" then such HTTP errors will cause the request
5582 or response to be rejected.
5587 -----------------------------------------------------------------------------
5590 NAME: forward_timeout
5593 LOC: Config.Timeout.forward
5596 This parameter specifies how long Squid should at most attempt in
5597 finding a forwarding path for the request before giving up.
5600 NAME: connect_timeout
5603 LOC: Config.Timeout.connect
5606 This parameter specifies how long to wait for the TCP connect to
5607 the requested server or peer to complete before Squid should
5608 attempt to find another path where to forward the request.
5611 NAME: peer_connect_timeout
5614 LOC: Config.Timeout.peer_connect
5617 This parameter specifies how long to wait for a pending TCP
5618 connection to a peer cache. The default is 30 seconds. You
5619 may also set different timeout values for individual neighbors
5620 with the 'connect-timeout' option on a 'cache_peer' line.
5626 LOC: Config.Timeout.read
5629 The read_timeout is applied on server-side connections. After
5630 each successful read(), the timeout will be extended by this
5631 amount. If no data is read again after this amount of time,
5632 the request is aborted and logged with ERR_READ_TIMEOUT. The
5633 default is 15 minutes.
5639 LOC: Config.Timeout.write
5642 This timeout is tracked for all connections that have data
5643 available for writing and are waiting for the socket to become
5644 ready. After each successful write, the timeout is extended by
5645 the configured amount. If Squid has data to write but the
5646 connection is not ready for the configured duration, the
5647 transaction associated with the connection is terminated. The
5648 default is 15 minutes.
5651 NAME: request_timeout
5653 LOC: Config.Timeout.request
5656 How long to wait for complete HTTP request headers after initial
5657 connection establishment.
5660 NAME: client_idle_pconn_timeout persistent_request_timeout
5662 LOC: Config.Timeout.clientIdlePconn
5665 How long to wait for the next HTTP request on a persistent
5666 client connection after the previous request completes.
5669 NAME: client_lifetime
5672 LOC: Config.Timeout.lifetime
5675 The maximum amount of time a client (browser) is allowed to
5676 remain connected to the cache process. This protects the Cache
5677 from having a lot of sockets (and hence file descriptors) tied up
5678 in a CLOSE_WAIT state from remote clients that go away without
5679 properly shutting down (either because of a network failure or
5680 because of a poor client implementation). The default is one
5683 NOTE: The default value is intended to be much larger than any
5684 client would ever need to be connected to your cache. You
5685 should probably change client_lifetime only as a last resort.
5686 If you seem to have many client connections tying up
5687 filedescriptors, we recommend first tuning the read_timeout,
5688 request_timeout, persistent_request_timeout and quick_abort values.
5691 NAME: half_closed_clients
5693 LOC: Config.onoff.half_closed_clients
5696 Some clients may shutdown the sending side of their TCP
5697 connections, while leaving their receiving sides open. Sometimes,
5698 Squid can not tell the difference between a half-closed and a
5699 fully-closed TCP connection.
5701 By default, Squid will immediately close client connections when
5702 read(2) returns "no more data to read."
5704 Change this option to 'on' and Squid will keep open connections
5705 until a read(2) or write(2) on the socket returns an error.
5706 This may show some benefits for reverse proxies. But if not
5707 it is recommended to leave OFF.
5710 NAME: server_idle_pconn_timeout pconn_timeout
5712 LOC: Config.Timeout.serverIdlePconn
5715 Timeout for idle persistent connections to servers and other
5722 LOC: Ident::TheConfig.timeout
5725 Maximum time to wait for IDENT lookups to complete.
5727 If this is too high, and you enabled IDENT lookups from untrusted
5728 users, you might be susceptible to denial-of-service by having
5729 many ident requests going at once.
5732 NAME: shutdown_lifetime
5735 LOC: Config.shutdownLifetime
5738 When SIGTERM or SIGHUP is received, the cache is put into
5739 "shutdown pending" mode until all active sockets are closed.
5740 This value is the lifetime to set for all open descriptors
5741 during shutdown mode. Any active clients after this many
5742 seconds will receive a 'timeout' message.
5746 ADMINISTRATIVE PARAMETERS
5747 -----------------------------------------------------------------------------
5753 LOC: Config.adminEmail
5755 Email-address of local cache manager who will receive
5756 mail if the cache dies. The default is "webmaster".
5762 LOC: Config.EmailFrom
5764 From: email-address for mail sent when the cache dies.
5765 The default is to use 'squid@unique_hostname'.
5767 See also: unique_hostname directive.
5773 LOC: Config.EmailProgram
5775 Email program used to send mail if the cache dies.
5776 The default is "mail". The specified program must comply
5777 with the standard Unix mail syntax:
5778 mail-program recipient < mailfile
5780 Optional command line options can be specified.
5783 NAME: cache_effective_user
5785 DEFAULT: @DEFAULT_CACHE_EFFECTIVE_USER@
5786 LOC: Config.effectiveUser
5788 If you start Squid as root, it will change its effective/real
5789 UID/GID to the user specified below. The default is to change
5790 to UID of @DEFAULT_CACHE_EFFECTIVE_USER@.
5791 see also; cache_effective_group
5794 NAME: cache_effective_group
5797 DEFAULT_DOC: Use system group memberships of the cache_effective_user account
5798 LOC: Config.effectiveGroup
5800 Squid sets the GID to the effective user's default group ID
5801 (taken from the password file) and supplementary group list
5802 from the groups membership.
5804 If you want Squid to run with a specific GID regardless of
5805 the group memberships of the effective user then set this
5806 to the group (or GID) you want Squid to run as. When set
5807 all other group privileges of the effective user are ignored
5808 and only this GID is effective. If Squid is not started as
5809 root the user starting Squid MUST be member of the specified
5812 This option is not recommended by the Squid Team.
5813 Our preference is for administrators to configure a secure
5814 user account for squid with UID/GID matching system policies.
5817 NAME: httpd_suppress_version_string
5821 LOC: Config.onoff.httpd_suppress_version_string
5823 Suppress Squid version string info in HTTP headers and HTML error pages.
5826 NAME: visible_hostname
5828 LOC: Config.visibleHostname
5830 DEFAULT_DOC: Automatically detect the system host name
5832 If you want to present a special hostname in error messages, etc,
5833 define this. Otherwise, the return value of gethostname()
5834 will be used. If you have multiple caches in a cluster and
5835 get errors about IP-forwarding you must set them to have individual
5836 names with this setting.
5839 NAME: unique_hostname
5841 LOC: Config.uniqueHostname
5843 DEFAULT_DOC: Copy the value from visible_hostname
5845 If you want to have multiple machines with the same
5846 'visible_hostname' you must give each machine a different
5847 'unique_hostname' so forwarding loops can be detected.
5850 NAME: hostname_aliases
5852 LOC: Config.hostnameAliases
5855 A list of other DNS names your cache has.
5863 Minimum umask which should be enforced while the proxy
5864 is running, in addition to the umask set at startup.
5866 For a traditional octal representation of umasks, start
5871 OPTIONS FOR THE CACHE REGISTRATION SERVICE
5872 -----------------------------------------------------------------------------
5874 This section contains parameters for the (optional) cache
5875 announcement service. This service is provided to help
5876 cache administrators locate one another in order to join or
5877 create cache hierarchies.
5879 An 'announcement' message is sent (via UDP) to the registration
5880 service by Squid. By default, the announcement message is NOT
5881 SENT unless you enable it with 'announce_period' below.
5883 The announcement message includes your hostname, plus the
5884 following information from this configuration file:
5890 All current information is processed regularly and made
5891 available on the Web at http://www.ircache.net/Cache/Tracker/.
5894 NAME: announce_period
5896 LOC: Config.Announce.period
5898 DEFAULT_DOC: Announcement messages disabled.
5900 This is how frequently to send cache announcements.
5902 To enable announcing your cache, just set an announce period.
5905 announce_period 1 day
5910 DEFAULT: tracker.ircache.net
5911 LOC: Config.Announce.host
5913 Set the hostname where announce registration messages will be sent.
5915 See also announce_port and announce_file
5921 LOC: Config.Announce.file
5923 The contents of this file will be included in the announce
5924 registration messages.
5930 LOC: Config.Announce.port
5932 Set the port where announce registration messages will be sent.
5934 See also announce_host and announce_file
5938 HTTPD-ACCELERATOR OPTIONS
5939 -----------------------------------------------------------------------------
5942 NAME: httpd_accel_surrogate_id
5945 DEFAULT_DOC: visible_hostname is used if no specific ID is set.
5946 LOC: Config.Accel.surrogate_id
5948 Surrogates (http://www.esi.org/architecture_spec_1.0.html)
5949 need an identification token to allow control targeting. Because
5950 a farm of surrogates may all perform the same tasks, they may share
5951 an identification token.
5954 NAME: http_accel_surrogate_remote
5958 LOC: Config.onoff.surrogate_is_remote
5960 Remote surrogates (such as those in a CDN) honour the header
5961 "Surrogate-Control: no-store-remote".
5963 Set this to on to have squid behave as a remote surrogate.
5967 IFDEF: USE_SQUID_ESI
5968 COMMENT: libxml2|expat|custom
5970 LOC: ESIParser::Type
5973 ESI markup is not strictly XML compatible. The custom ESI parser
5974 will give higher performance, but cannot handle non ASCII character
5979 DELAY POOL PARAMETERS
5980 -----------------------------------------------------------------------------
5984 TYPE: delay_pool_count
5986 IFDEF: USE_DELAY_POOLS
5989 This represents the number of delay pools to be used. For example,
5990 if you have one class 2 delay pool and one class 3 delays pool, you
5991 have a total of 2 delay pools.
5993 See also delay_parameters, delay_class, delay_access for pool
5994 configuration details.
5998 TYPE: delay_pool_class
6000 IFDEF: USE_DELAY_POOLS
6003 This defines the class of each delay pool. There must be exactly one
6004 delay_class line for each delay pool. For example, to define two
6005 delay pools, one of class 2 and one of class 3, the settings above
6009 delay_pools 4 # 4 delay pools
6010 delay_class 1 2 # pool 1 is a class 2 pool
6011 delay_class 2 3 # pool 2 is a class 3 pool
6012 delay_class 3 4 # pool 3 is a class 4 pool
6013 delay_class 4 5 # pool 4 is a class 5 pool
6015 The delay pool classes are:
6017 class 1 Everything is limited by a single aggregate
6020 class 2 Everything is limited by a single aggregate
6021 bucket as well as an "individual" bucket chosen
6022 from bits 25 through 32 of the IPv4 address.
6024 class 3 Everything is limited by a single aggregate
6025 bucket as well as a "network" bucket chosen
6026 from bits 17 through 24 of the IP address and a
6027 "individual" bucket chosen from bits 17 through
6028 32 of the IPv4 address.
6030 class 4 Everything in a class 3 delay pool, with an
6031 additional limit on a per user basis. This
6032 only takes effect if the username is established
6033 in advance - by forcing authentication in your
6036 class 5 Requests are grouped according their tag (see
6037 external_acl's tag= reply).
6040 Each pool also requires a delay_parameters directive to configure the pool size
6041 and speed limits used whenever the pool is applied to a request. Along with
6042 a set of delay_access directives to determine when it is used.
6044 NOTE: If an IP address is a.b.c.d
6045 -> bits 25 through 32 are "d"
6046 -> bits 17 through 24 are "c"
6047 -> bits 17 through 32 are "c * 256 + d"
6049 NOTE-2: Due to the use of bitmasks in class 2,3,4 pools they only apply to
6050 IPv4 traffic. Class 1 and 5 pools may be used with IPv6 traffic.
6052 This clause only supports fast acl types.
6053 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6055 See also delay_parameters and delay_access.
6059 TYPE: delay_pool_access
6061 DEFAULT_DOC: Deny using the pool, unless allow rules exist in squid.conf for the pool.
6062 IFDEF: USE_DELAY_POOLS
6065 This is used to determine which delay pool a request falls into.
6067 delay_access is sorted per pool and the matching starts with pool 1,
6068 then pool 2, ..., and finally pool N. The first delay pool where the
6069 request is allowed is selected for the request. If it does not allow
6070 the request to any pool then the request is not delayed (default).
6072 For example, if you want some_big_clients in delay
6073 pool 1 and lotsa_little_clients in delay pool 2:
6075 delay_access 1 allow some_big_clients
6076 delay_access 1 deny all
6077 delay_access 2 allow lotsa_little_clients
6078 delay_access 2 deny all
6079 delay_access 3 allow authenticated_clients
6081 See also delay_parameters and delay_class.
6085 NAME: delay_parameters
6086 TYPE: delay_pool_rates
6088 IFDEF: USE_DELAY_POOLS
6091 This defines the parameters for a delay pool. Each delay pool has
6092 a number of "buckets" associated with it, as explained in the
6093 description of delay_class.
6095 For a class 1 delay pool, the syntax is:
6097 delay_parameters pool aggregate
6099 For a class 2 delay pool:
6101 delay_parameters pool aggregate individual
6103 For a class 3 delay pool:
6105 delay_parameters pool aggregate network individual
6107 For a class 4 delay pool:
6109 delay_parameters pool aggregate network individual user
6111 For a class 5 delay pool:
6113 delay_parameters pool tagrate
6115 The option variables are:
6117 pool a pool number - ie, a number between 1 and the
6118 number specified in delay_pools as used in
6121 aggregate the speed limit parameters for the aggregate bucket
6124 individual the speed limit parameters for the individual
6125 buckets (class 2, 3).
6127 network the speed limit parameters for the network buckets
6130 user the speed limit parameters for the user buckets
6133 tagrate the speed limit parameters for the tag buckets
6136 A pair of delay parameters is written restore/maximum, where restore is
6137 the number of bytes (not bits - modem and network speeds are usually
6138 quoted in bits) per second placed into the bucket, and maximum is the
6139 maximum number of bytes which can be in the bucket at any time.
6141 There must be one delay_parameters line for each delay pool.
6144 For example, if delay pool number 1 is a class 2 delay pool as in the
6145 above example, and is being used to strictly limit each host to 64Kbit/sec
6146 (plus overheads), with no overall limit, the line is:
6148 delay_parameters 1 -1/-1 8000/8000
6150 Note that 8 x 8000 KByte/sec -> 64Kbit/sec.
6152 Note that the figure -1 is used to represent "unlimited".
6155 And, if delay pool number 2 is a class 3 delay pool as in the above
6156 example, and you want to limit it to a total of 256Kbit/sec (strict limit)
6157 with each 8-bit network permitted 64Kbit/sec (strict limit) and each
6158 individual host permitted 4800bit/sec with a bucket maximum size of 64Kbits
6159 to permit a decent web page to be downloaded at a decent speed
6160 (if the network is not being limited due to overuse) but slow down
6161 large downloads more significantly:
6163 delay_parameters 2 32000/32000 8000/8000 600/8000
6165 Note that 8 x 32000 KByte/sec -> 256Kbit/sec.
6166 8 x 8000 KByte/sec -> 64Kbit/sec.
6167 8 x 600 Byte/sec -> 4800bit/sec.
6170 Finally, for a class 4 delay pool as in the example - each user will
6171 be limited to 128Kbits/sec no matter how many workstations they are logged into.:
6173 delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000
6176 See also delay_class and delay_access.
6180 NAME: delay_initial_bucket_level
6181 COMMENT: (percent, 0-100)
6184 IFDEF: USE_DELAY_POOLS
6185 LOC: Config.Delay.initial
6187 The initial bucket percentage is used to determine how much is put
6188 in each bucket when squid starts, is reconfigured, or first notices
6189 a host accessing it (in class 2 and class 3, individual hosts and
6190 networks only have buckets associated with them once they have been
6195 CLIENT DELAY POOL PARAMETERS
6196 -----------------------------------------------------------------------------
6199 NAME: client_delay_pools
6200 TYPE: client_delay_pool_count
6202 IFDEF: USE_DELAY_POOLS
6203 LOC: Config.ClientDelay
6205 This option specifies the number of client delay pools used. It must
6206 preceed other client_delay_* options.
6209 client_delay_pools 2
6211 See also client_delay_parameters and client_delay_access.
6214 NAME: client_delay_initial_bucket_level
6215 COMMENT: (percent, 0-no_limit)
6218 IFDEF: USE_DELAY_POOLS
6219 LOC: Config.ClientDelay.initial
6221 This option determines the initial bucket size as a percentage of
6222 max_bucket_size from client_delay_parameters. Buckets are created
6223 at the time of the "first" connection from the matching IP. Idle
6224 buckets are periodically deleted up.
6226 You can specify more than 100 percent but note that such "oversized"
6227 buckets are not refilled until their size goes down to max_bucket_size
6228 from client_delay_parameters.
6231 client_delay_initial_bucket_level 50
6234 NAME: client_delay_parameters
6235 TYPE: client_delay_pool_rates
6237 IFDEF: USE_DELAY_POOLS
6238 LOC: Config.ClientDelay
6241 This option configures client-side bandwidth limits using the
6244 client_delay_parameters pool speed_limit max_bucket_size
6246 pool is an integer ID used for client_delay_access matching.
6248 speed_limit is bytes added to the bucket per second.
6250 max_bucket_size is the maximum size of a bucket, enforced after any
6251 speed_limit additions.
6253 Please see the delay_parameters option for more information and
6257 client_delay_parameters 1 1024 2048
6258 client_delay_parameters 2 51200 16384
6260 See also client_delay_access.
6264 NAME: client_delay_access
6265 TYPE: client_delay_pool_access
6267 DEFAULT_DOC: Deny use of the pool, unless allow rules exist in squid.conf for the pool.
6268 IFDEF: USE_DELAY_POOLS
6269 LOC: Config.ClientDelay
6271 This option determines the client-side delay pool for the
6274 client_delay_access pool_ID allow|deny acl_name
6276 All client_delay_access options are checked in their pool ID
6277 order, starting with pool 1. The first checked pool with allowed
6278 request is selected for the request. If no ACL matches or there
6279 are no client_delay_access options, the request bandwidth is not
6282 The ACL-selected pool is then used to find the
6283 client_delay_parameters for the request. Client-side pools are
6284 not used to aggregate clients. Clients are always aggregated
6285 based on their source IP addresses (one bucket per source IP).
6287 This clause only supports fast acl types.
6288 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6289 Additionally, only the client TCP connection details are available.
6290 ACLs testing HTTP properties will not work.
6292 Please see delay_access for more examples.
6295 client_delay_access 1 allow low_rate_network
6296 client_delay_access 2 allow vips_network
6299 See also client_delay_parameters and client_delay_pools.
6303 WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS
6304 -----------------------------------------------------------------------------
6309 LOC: Config.Wccp.router
6311 DEFAULT_DOC: WCCP disabled.
6314 Use this option to define your WCCP ``home'' router for
6317 wccp_router supports a single WCCP(v1) router
6319 wccp2_router supports multiple WCCPv2 routers
6321 only one of the two may be used at the same time and defines
6322 which version of WCCP to use.
6326 TYPE: IpAddress_list
6327 LOC: Config.Wccp2.router
6329 DEFAULT_DOC: WCCPv2 disabled.
6332 Use this option to define your WCCP ``home'' router for
6335 wccp_router supports a single WCCP(v1) router
6337 wccp2_router supports multiple WCCPv2 routers
6339 only one of the two may be used at the same time and defines
6340 which version of WCCP to use.
6345 LOC: Config.Wccp.version
6349 This directive is only relevant if you need to set up WCCP(v1)
6350 to some very old and end-of-life Cisco routers. In all other
6351 setups it must be left unset or at the default setting.
6352 It defines an internal version in the WCCP(v1) protocol,
6353 with version 4 being the officially documented protocol.
6355 According to some users, Cisco IOS 11.2 and earlier only
6356 support WCCP version 3. If you're using that or an earlier
6357 version of IOS, you may need to change this value to 3, otherwise
6358 do not specify this parameter.
6361 NAME: wccp2_rebuild_wait
6363 LOC: Config.Wccp2.rebuildwait
6367 If this is enabled Squid will wait for the cache dir rebuild to finish
6368 before sending the first wccp2 HereIAm packet
6371 NAME: wccp2_forwarding_method
6373 LOC: Config.Wccp2.forwarding_method
6377 WCCP2 allows the setting of forwarding methods between the
6378 router/switch and the cache. Valid values are as follows:
6380 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
6381 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
6383 Currently (as of IOS 12.4) cisco routers only support GRE.
6384 Cisco switches only support the L2 redirect assignment method.
6387 NAME: wccp2_return_method
6389 LOC: Config.Wccp2.return_method
6393 WCCP2 allows the setting of return methods between the
6394 router/switch and the cache for packets that the cache
6395 decides not to handle. Valid values are as follows:
6397 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
6398 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
6400 Currently (as of IOS 12.4) cisco routers only support GRE.
6401 Cisco switches only support the L2 redirect assignment.
6403 If the "ip wccp redirect exclude in" command has been
6404 enabled on the cache interface, then it is still safe for
6405 the proxy server to use a l2 redirect method even if this
6406 option is set to GRE.
6409 NAME: wccp2_assignment_method
6411 LOC: Config.Wccp2.assignment_method
6415 WCCP2 allows the setting of methods to assign the WCCP hash
6416 Valid values are as follows:
6418 hash - Hash assignment
6419 mask - Mask assignment
6421 As a general rule, cisco routers support the hash assignment method
6422 and cisco switches support the mask assignment method.
6427 LOC: Config.Wccp2.info
6428 DEFAULT_IF_NONE: standard 0
6429 DEFAULT_DOC: Use the 'web-cache' standard service.
6432 WCCP2 allows for multiple traffic services. There are two
6433 types: "standard" and "dynamic". The standard type defines
6434 one service id - http (id 0). The dynamic service ids can be from
6435 51 to 255 inclusive. In order to use a dynamic service id
6436 one must define the type of traffic to be redirected; this is done
6437 using the wccp2_service_info option.
6439 The "standard" type does not require a wccp2_service_info option,
6440 just specifying the service id will suffice.
6442 MD5 service authentication can be enabled by adding
6443 "password=<password>" to the end of this service declaration.
6447 wccp2_service standard 0 # for the 'web-cache' standard service
6448 wccp2_service dynamic 80 # a dynamic service type which will be
6449 # fleshed out with subsequent options.
6450 wccp2_service standard 0 password=foo
6453 NAME: wccp2_service_info
6454 TYPE: wccp2_service_info
6455 LOC: Config.Wccp2.info
6459 Dynamic WCCPv2 services require further information to define the
6460 traffic you wish to have diverted.
6464 wccp2_service_info <id> protocol=<protocol> flags=<flag>,<flag>..
6465 priority=<priority> ports=<port>,<port>..
6467 The relevant WCCPv2 flags:
6468 + src_ip_hash, dst_ip_hash
6469 + source_port_hash, dst_port_hash
6470 + src_ip_alt_hash, dst_ip_alt_hash
6471 + src_port_alt_hash, dst_port_alt_hash
6474 The port list can be one to eight entries.
6478 wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source
6479 priority=240 ports=80
6481 Note: the service id must have been defined by a previous
6482 'wccp2_service dynamic <id>' entry.
6487 LOC: Config.Wccp2.weight
6491 Each cache server gets assigned a set of the destination
6492 hash proportional to their weight.
6497 LOC: Config.Wccp.address
6499 DEFAULT_DOC: Address selected by the operating system.
6502 Use this option if you require WCCPv2 to use a specific
6505 The default behavior is to not bind to any specific address.
6510 LOC: Config.Wccp2.address
6512 DEFAULT_DOC: Address selected by the operating system.
6515 Use this option if you require WCCP to use a specific
6518 The default behavior is to not bind to any specific address.
6522 PERSISTENT CONNECTION HANDLING
6523 -----------------------------------------------------------------------------
6525 Also see "pconn_timeout" in the TIMEOUTS section
6528 NAME: client_persistent_connections
6530 LOC: Config.onoff.client_pconns
6533 Persistent connection support for clients.
6534 Squid uses persistent connections (when allowed). You can use
6535 this option to disable persistent connections with clients.
6538 NAME: server_persistent_connections
6540 LOC: Config.onoff.server_pconns
6543 Persistent connection support for servers.
6544 Squid uses persistent connections (when allowed). You can use
6545 this option to disable persistent connections with servers.
6548 NAME: persistent_connection_after_error
6550 LOC: Config.onoff.error_pconns
6553 With this directive the use of persistent connections after
6554 HTTP errors can be disabled. Useful if you have clients
6555 who fail to handle errors on persistent connections proper.
6558 NAME: detect_broken_pconn
6560 LOC: Config.onoff.detect_broken_server_pconns
6563 Some servers have been found to incorrectly signal the use
6564 of HTTP/1.0 persistent connections even on replies not
6565 compatible, causing significant delays. This server problem
6566 has mostly been seen on redirects.
6568 By enabling this directive Squid attempts to detect such
6569 broken replies and automatically assume the reply is finished
6570 after 10 seconds timeout.
6574 CACHE DIGEST OPTIONS
6575 -----------------------------------------------------------------------------
6578 NAME: digest_generation
6579 IFDEF: USE_CACHE_DIGESTS
6581 LOC: Config.onoff.digest_generation
6584 This controls whether the server will generate a Cache Digest
6585 of its contents. By default, Cache Digest generation is
6586 enabled if Squid is compiled with --enable-cache-digests defined.
6589 NAME: digest_bits_per_entry
6590 IFDEF: USE_CACHE_DIGESTS
6592 LOC: Config.digest.bits_per_entry
6595 This is the number of bits of the server's Cache Digest which
6596 will be associated with the Digest entry for a given HTTP
6597 Method and URL (public key) combination. The default is 5.
6600 NAME: digest_rebuild_period
6601 IFDEF: USE_CACHE_DIGESTS
6604 LOC: Config.digest.rebuild_period
6607 This is the wait time between Cache Digest rebuilds.
6610 NAME: digest_rewrite_period
6612 IFDEF: USE_CACHE_DIGESTS
6614 LOC: Config.digest.rewrite_period
6617 This is the wait time between Cache Digest writes to
6621 NAME: digest_swapout_chunk_size
6624 IFDEF: USE_CACHE_DIGESTS
6625 LOC: Config.digest.swapout_chunk_size
6628 This is the number of bytes of the Cache Digest to write to
6629 disk at a time. It defaults to 4096 bytes (4KB), the Squid
6633 NAME: digest_rebuild_chunk_percentage
6634 COMMENT: (percent, 0-100)
6635 IFDEF: USE_CACHE_DIGESTS
6637 LOC: Config.digest.rebuild_chunk_percentage
6640 This is the percentage of the Cache Digest to be scanned at a
6641 time. By default it is set to 10% of the Cache Digest.
6646 -----------------------------------------------------------------------------
6651 LOC: Config.Port.snmp
6653 DEFAULT_DOC: SNMP disabled.
6656 The port number where Squid listens for SNMP requests. To enable
6657 SNMP support set this to a suitable port number. Port number
6658 3401 is often used for the Squid SNMP agent. By default it's
6659 set to "0" (disabled)
6667 LOC: Config.accessList.snmp
6669 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
6672 Allowing or denying access to the SNMP port.
6674 All access to the agent is denied by default.
6677 snmp_access allow|deny [!]aclname ...
6679 This clause only supports fast acl types.
6680 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6683 snmp_access allow snmppublic localhost
6684 snmp_access deny all
6687 NAME: snmp_incoming_address
6689 LOC: Config.Addrs.snmp_incoming
6691 DEFAULT_DOC: Accept SNMP packets from all machine interfaces.
6694 Just like 'udp_incoming_address', but for the SNMP port.
6696 snmp_incoming_address is used for the SNMP socket receiving
6697 messages from SNMP agents.
6699 The default snmp_incoming_address is to listen on all
6700 available network interfaces.
6703 NAME: snmp_outgoing_address
6705 LOC: Config.Addrs.snmp_outgoing
6707 DEFAULT_DOC: Use snmp_incoming_address or an address selected by the operating system.
6710 Just like 'udp_outgoing_address', but for the SNMP port.
6712 snmp_outgoing_address is used for SNMP packets returned to SNMP
6715 If snmp_outgoing_address is not set it will use the same socket
6716 as snmp_incoming_address. Only change this if you want to have
6717 SNMP replies sent using another address than where this Squid
6718 listens for SNMP queries.
6720 NOTE, snmp_incoming_address and snmp_outgoing_address can not have
6721 the same value since they both use the same port.
6726 -----------------------------------------------------------------------------
6729 NAME: icp_port udp_port
6732 DEFAULT_DOC: ICP disabled.
6733 LOC: Config.Port.icp
6735 The port number where Squid sends and receives ICP queries to
6736 and from neighbor caches. The standard UDP port for ICP is 3130.
6739 icp_port @DEFAULT_ICP_PORT@
6746 DEFAULT_DOC: HTCP disabled.
6747 LOC: Config.Port.htcp
6749 The port number where Squid sends and receives HTCP queries to
6750 and from neighbor caches. To turn it on you want to set it to
6757 NAME: log_icp_queries
6761 LOC: Config.onoff.log_udp
6763 If set, ICP queries are logged to access.log. You may wish
6764 do disable this if your ICP load is VERY high to speed things
6765 up or to simplify log analysis.
6768 NAME: udp_incoming_address
6770 LOC:Config.Addrs.udp_incoming
6772 DEFAULT_DOC: Accept packets from all machine interfaces.
6774 udp_incoming_address is used for UDP packets received from other
6777 The default behavior is to not bind to any specific address.
6779 Only change this if you want to have all UDP queries received on
6780 a specific interface/address.
6782 NOTE: udp_incoming_address is used by the ICP, HTCP, and DNS
6783 modules. Altering it will affect all of them in the same manner.
6785 see also; udp_outgoing_address
6787 NOTE, udp_incoming_address and udp_outgoing_address can not
6788 have the same value since they both use the same port.
6791 NAME: udp_outgoing_address
6793 LOC: Config.Addrs.udp_outgoing
6795 DEFAULT_DOC: Use udp_incoming_address or an address selected by the operating system.
6797 udp_outgoing_address is used for UDP packets sent out to other
6800 The default behavior is to not bind to any specific address.
6802 Instead it will use the same socket as udp_incoming_address.
6803 Only change this if you want to have UDP queries sent using another
6804 address than where this Squid listens for UDP queries from other
6807 NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS
6808 modules. Altering it will affect all of them in the same manner.
6810 see also; udp_incoming_address
6812 NOTE, udp_incoming_address and udp_outgoing_address can not
6813 have the same value since they both use the same port.
6820 LOC: Config.onoff.icp_hit_stale
6822 If you want to return ICP_HIT for stale cache objects, set this
6823 option to 'on'. If you have sibling relationships with caches
6824 in other administrative domains, this should be 'off'. If you only
6825 have sibling relationships with caches under your control,
6826 it is probably okay to set this to 'on'.
6827 If set to 'on', your siblings should use the option "allow-miss"
6828 on their cache_peer lines for connecting to you.
6831 NAME: minimum_direct_hops
6834 LOC: Config.minDirectHops
6836 If using the ICMP pinging stuff, do direct fetches for sites
6837 which are no more than this many hops away.
6840 NAME: minimum_direct_rtt
6844 LOC: Config.minDirectRtt
6846 If using the ICMP pinging stuff, do direct fetches for sites
6847 which are no more than this many rtt milliseconds away.
6853 LOC: Config.Netdb.low
6855 The low water mark for the ICMP measurement database.
6857 Note: high watermark controlled by netdb_high directive.
6859 These watermarks are counts, not percents. The defaults are
6860 (low) 900 and (high) 1000. When the high water mark is
6861 reached, database entries will be deleted until the low
6868 LOC: Config.Netdb.high
6870 The high water mark for the ICMP measurement database.
6872 Note: low watermark controlled by netdb_low directive.
6874 These watermarks are counts, not percents. The defaults are
6875 (low) 900 and (high) 1000. When the high water mark is
6876 reached, database entries will be deleted until the low
6880 NAME: netdb_ping_period
6882 LOC: Config.Netdb.period
6885 The minimum period for measuring a site. There will be at
6886 least this much delay between successive pings to the same
6887 network. The default is five minutes.
6894 LOC: Config.onoff.query_icmp
6896 If you want to ask your peers to include ICMP data in their ICP
6897 replies, enable this option.
6899 If your peer has configured Squid (during compilation) with
6900 '--enable-icmp' that peer will send ICMP pings to origin server
6901 sites of the URLs it receives. If you enable this option the
6902 ICP replies from that peer will include the ICMP data (if available).
6903 Then, when choosing a parent cache, Squid will choose the parent with
6904 the minimal RTT to the origin server. When this happens, the
6905 hierarchy field of the access.log will be
6906 "CLOSEST_PARENT_MISS". This option is off by default.
6909 NAME: test_reachability
6913 LOC: Config.onoff.test_reachability
6915 When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
6916 instead of ICP_MISS if the target host is NOT in the ICMP
6917 database, or has a zero RTT.
6920 NAME: icp_query_timeout
6923 DEFAULT_DOC: Dynamic detection.
6925 LOC: Config.Timeout.icp_query
6927 Normally Squid will automatically determine an optimal ICP
6928 query timeout value based on the round-trip-time of recent ICP
6929 queries. If you want to override the value determined by
6930 Squid, set this 'icp_query_timeout' to a non-zero value. This
6931 value is specified in MILLISECONDS, so, to use a 2-second
6932 timeout (the old default), you would write:
6934 icp_query_timeout 2000
6937 NAME: maximum_icp_query_timeout
6941 LOC: Config.Timeout.icp_query_max
6943 Normally the ICP query timeout is determined dynamically. But
6944 sometimes it can lead to very large values (say 5 seconds).
6945 Use this option to put an upper limit on the dynamic timeout
6946 value. Do NOT use this option to always use a fixed (instead
6947 of a dynamic) timeout value. To set a fixed timeout see the
6948 'icp_query_timeout' directive.
6951 NAME: minimum_icp_query_timeout
6955 LOC: Config.Timeout.icp_query_min
6957 Normally the ICP query timeout is determined dynamically. But
6958 sometimes it can lead to very small timeouts, even lower than
6959 the normal latency variance on your link due to traffic.
6960 Use this option to put an lower limit on the dynamic timeout
6961 value. Do NOT use this option to always use a fixed (instead
6962 of a dynamic) timeout value. To set a fixed timeout see the
6963 'icp_query_timeout' directive.
6966 NAME: background_ping_rate
6970 LOC: Config.backgroundPingRate
6972 Controls how often the ICP pings are sent to siblings that
6973 have background-ping set.
6977 MULTICAST ICP OPTIONS
6978 -----------------------------------------------------------------------------
6983 LOC: Config.mcast_group_list
6986 This tag specifies a list of multicast groups which your server
6987 should join to receive multicasted ICP queries.
6989 NOTE! Be very careful what you put here! Be sure you
6990 understand the difference between an ICP _query_ and an ICP
6991 _reply_. This option is to be set only if you want to RECEIVE
6992 multicast queries. Do NOT set this option to SEND multicast
6993 ICP (use cache_peer for that). ICP replies are always sent via
6994 unicast, so this option does not affect whether or not you will
6995 receive replies from multicast group members.
6997 You must be very careful to NOT use a multicast address which
6998 is already in use by another group of caches.
7000 If you are unsure about multicast, please read the Multicast
7001 chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
7003 Usage: mcast_groups 239.128.16.128 224.0.1.20
7005 By default, Squid doesn't listen on any multicast groups.
7008 NAME: mcast_miss_addr
7009 IFDEF: MULTICAST_MISS_STREAM
7011 LOC: Config.mcast_miss.addr
7013 DEFAULT_DOC: disabled.
7015 If you enable this option, every "cache miss" URL will
7016 be sent out on the specified multicast address.
7018 Do not enable this option unless you are are absolutely
7019 certain you understand what you are doing.
7022 NAME: mcast_miss_ttl
7023 IFDEF: MULTICAST_MISS_STREAM
7025 LOC: Config.mcast_miss.ttl
7028 This is the time-to-live value for packets multicasted
7029 when multicasting off cache miss URLs is enabled. By
7030 default this is set to 'site scope', i.e. 16.
7033 NAME: mcast_miss_port
7034 IFDEF: MULTICAST_MISS_STREAM
7036 LOC: Config.mcast_miss.port
7039 This is the port number to be used in conjunction with
7043 NAME: mcast_miss_encode_key
7044 IFDEF: MULTICAST_MISS_STREAM
7046 LOC: Config.mcast_miss.encode_key
7047 DEFAULT: XXXXXXXXXXXXXXXX
7049 The URLs that are sent in the multicast miss stream are
7050 encrypted. This is the encryption key.
7053 NAME: mcast_icp_query_timeout
7057 LOC: Config.Timeout.mcast_icp_query
7059 For multicast peers, Squid regularly sends out ICP "probes" to
7060 count how many other peers are listening on the given multicast
7061 address. This value specifies how long Squid should wait to
7062 count all the replies. The default is 2000 msec, or 2
7067 INTERNAL ICON OPTIONS
7068 -----------------------------------------------------------------------------
7071 NAME: icon_directory
7073 LOC: Config.icons.directory
7074 DEFAULT: @DEFAULT_ICON_DIR@
7076 Where the icons are stored. These are normally kept in
7080 NAME: global_internal_static
7082 LOC: Config.onoff.global_internal_static
7085 This directive controls is Squid should intercept all requests for
7086 /squid-internal-static/ no matter which host the URL is requesting
7087 (default on setting), or if nothing special should be done for
7088 such URLs (off setting). The purpose of this directive is to make
7089 icons etc work better in complex cache hierarchies where it may
7090 not always be possible for all corners in the cache mesh to reach
7091 the server generating a directory listing.
7094 NAME: short_icon_urls
7096 LOC: Config.icons.use_short_names
7099 If this is enabled Squid will use short URLs for icons.
7100 If disabled it will revert to the old behavior of including
7101 it's own name and port in the URL.
7103 If you run a complex cache hierarchy with a mix of Squid and
7104 other proxies you may need to disable this directive.
7109 -----------------------------------------------------------------------------
7112 NAME: error_directory
7114 LOC: Config.errorDirectory
7116 DEFAULT_DOC: Send error pages in the clients preferred language
7118 If you wish to create your own versions of the default
7119 error files to customize them to suit your company copy
7120 the error/template files to another directory and point
7123 WARNING: This option will disable multi-language support
7124 on error pages if used.
7126 The squid developers are interested in making squid available in
7127 a wide variety of languages. If you are making translations for a
7128 language that Squid does not currently provide please consider
7129 contributing your translation back to the project.
7130 http://wiki.squid-cache.org/Translations
7132 The squid developers working on translations are happy to supply drop-in
7133 translated error files in exchange for any new language contributions.
7136 NAME: error_default_language
7137 IFDEF: USE_ERR_LOCALES
7139 LOC: Config.errorDefaultLanguage
7141 DEFAULT_DOC: Generate English language pages.
7143 Set the default language which squid will send error pages in
7144 if no existing translation matches the clients language
7147 If unset (default) generic English will be used.
7149 The squid developers are interested in making squid available in
7150 a wide variety of languages. If you are interested in making
7151 translations for any language see the squid wiki for details.
7152 http://wiki.squid-cache.org/Translations
7155 NAME: error_log_languages
7156 IFDEF: USE_ERR_LOCALES
7158 LOC: Config.errorLogMissingLanguages
7161 Log to cache.log what languages users are attempting to
7162 auto-negotiate for translations.
7164 Successful negotiations are not logged. Only failures
7165 have meaning to indicate that Squid may need an upgrade
7166 of its error page translations.
7169 NAME: err_page_stylesheet
7171 LOC: Config.errorStylesheet
7172 DEFAULT: @DEFAULT_CONFIG_DIR@/errorpage.css
7174 CSS Stylesheet to pattern the display of Squid default error pages.
7176 For information on CSS see http://www.w3.org/Style/CSS/
7181 LOC: Config.errHtmlText
7184 HTML text to include in error messages. Make this a "mailto"
7185 URL to your admin address, or maybe just a link to your
7186 organizations Web page.
7188 To include this in your error messages, you must rewrite
7189 the error template files (found in the "errors" directory).
7190 Wherever you want the 'err_html_text' line to appear,
7191 insert a %L tag in the error template file.
7194 NAME: email_err_data
7197 LOC: Config.onoff.emailErrData
7200 If enabled, information about the occurred error will be
7201 included in the mailto links of the ERR pages (if %W is set)
7202 so that the email body contains the data.
7203 Syntax is <A HREF="mailto:%w%W">%w</A>
7208 LOC: Config.denyInfoList
7211 Usage: deny_info err_page_name acl
7212 or deny_info http://... acl
7213 or deny_info TCP_RESET acl
7215 This can be used to return a ERR_ page for requests which
7216 do not pass the 'http_access' rules. Squid remembers the last
7217 acl it evaluated in http_access, and if a 'deny_info' line exists
7218 for that ACL Squid returns a corresponding error page.
7220 The acl is typically the last acl on the http_access deny line which
7221 denied access. The exceptions to this rule are:
7222 - When Squid needs to request authentication credentials. It's then
7223 the first authentication related acl encountered
7224 - When none of the http_access lines matches. It's then the last
7225 acl processed on the last http_access line.
7226 - When the decision to deny access was made by an adaptation service,
7227 the acl name is the corresponding eCAP or ICAP service_name.
7229 NP: If providing your own custom error pages with error_directory
7230 you may also specify them by your custom file name:
7231 Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
7233 By defaut Squid will send "403 Forbidden". A different 4xx or 5xx
7234 may be specified by prefixing the file name with the code and a colon.
7235 e.g. 404:ERR_CUSTOM_ACCESS_DENIED
7237 Alternatively you can tell Squid to reset the TCP connection
7238 by specifying TCP_RESET.
7240 Or you can specify an error URL or URL pattern. The browsers will
7241 get redirected to the specified URL after formatting tags have
7242 been replaced. Redirect will be done with 302 or 307 according to
7243 HTTP/1.1 specs. A different 3xx code may be specified by prefixing
7244 the URL. e.g. 303:http://example.com/
7247 %a - username (if available. Password NOT included)
7250 %E - Error description
7252 %H - Request domain name
7253 %i - Client IP Address
7255 %o - Message result from external ACL helper
7256 %p - Request Port number
7257 %P - Request Protocol name
7258 %R - Request URL path
7259 %T - Timestamp in RFC 1123 format
7260 %U - Full canonical URL from client
7261 (HTTPS URLs terminate with *)
7262 %u - Full canonical URL from client
7263 %w - Admin email from squid.conf
7265 %% - Literal percent (%) code
7270 OPTIONS INFLUENCING REQUEST FORWARDING
7271 -----------------------------------------------------------------------------
7274 NAME: nonhierarchical_direct
7276 LOC: Config.onoff.nonhierarchical_direct
7279 By default, Squid will send any non-hierarchical requests
7280 (matching hierarchy_stoplist or not cacheable request type) direct
7283 When this is set to "off", Squid will prefer to send these
7284 requests to parents.
7286 Note that in most configurations, by turning this off you will only
7287 add latency to these request without any improvement in global hit
7290 This option only sets a preference. If the parent is unavailable a
7291 direct connection to the origin server may still be attempted. To
7292 completely prevent direct connections use never_direct.
7297 LOC: Config.onoff.prefer_direct
7300 Normally Squid tries to use parents for most requests. If you for some
7301 reason like it to first try going direct and only use a parent if
7302 going direct fails set this to on.
7304 By combining nonhierarchical_direct off and prefer_direct on you
7305 can set up Squid to use a parent as a backup path if going direct
7308 Note: If you want Squid to use parents for all requests see
7309 the never_direct directive. prefer_direct only modifies how Squid
7310 acts on cacheable requests.
7315 LOC: Config.accessList.AlwaysDirect
7317 DEFAULT_DOC: Prevent any cache_peer being used for this request.
7319 Usage: always_direct allow|deny [!]aclname ...
7321 Here you can use ACL elements to specify requests which should
7322 ALWAYS be forwarded by Squid to the origin servers without using
7323 any peers. For example, to always directly forward requests for
7324 local servers ignoring any parents or siblings you may have use
7327 acl local-servers dstdomain my.domain.net
7328 always_direct allow local-servers
7330 To always forward FTP requests directly, use
7333 always_direct allow FTP
7335 NOTE: There is a similar, but opposite option named
7336 'never_direct'. You need to be aware that "always_direct deny
7337 foo" is NOT the same thing as "never_direct allow foo". You
7338 may need to use a deny rule to exclude a more-specific case of
7339 some other rule. Example:
7341 acl local-external dstdomain external.foo.net
7342 acl local-servers dstdomain .foo.net
7343 always_direct deny local-external
7344 always_direct allow local-servers
7346 NOTE: If your goal is to make the client forward the request
7347 directly to the origin server bypassing Squid then this needs
7348 to be done in the client configuration. Squid configuration
7349 can only tell Squid how Squid should fetch the object.
7351 NOTE: This directive is not related to caching. The replies
7352 is cached as usual even if you use always_direct. To not cache
7353 the replies see the 'cache' directive.
7355 This clause supports both fast and slow acl types.
7356 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7361 LOC: Config.accessList.NeverDirect
7363 DEFAULT_DOC: Allow DNS results to be used for this request.
7365 Usage: never_direct allow|deny [!]aclname ...
7367 never_direct is the opposite of always_direct. Please read
7368 the description for always_direct if you have not already.
7370 With 'never_direct' you can use ACL elements to specify
7371 requests which should NEVER be forwarded directly to origin
7372 servers. For example, to force the use of a proxy for all
7373 requests, except those in your local domain use something like:
7375 acl local-servers dstdomain .foo.net
7376 never_direct deny local-servers
7377 never_direct allow all
7379 or if Squid is inside a firewall and there are local intranet
7380 servers inside the firewall use something like:
7382 acl local-intranet dstdomain .foo.net
7383 acl local-external dstdomain external.foo.net
7384 always_direct deny local-external
7385 always_direct allow local-intranet
7386 never_direct allow all
7388 This clause supports both fast and slow acl types.
7389 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7393 ADVANCED NETWORKING OPTIONS
7394 -----------------------------------------------------------------------------
7397 NAME: incoming_udp_average incoming_icp_average
7400 LOC: Config.comm_incoming.udp.average
7402 Heavy voodoo here. I can't even believe you are reading this.
7403 Are you crazy? Don't even think about adjusting these unless
7404 you understand the algorithms in comm_select.c first!
7407 NAME: incoming_tcp_average incoming_http_average
7410 LOC: Config.comm_incoming.tcp.average
7412 Heavy voodoo here. I can't even believe you are reading this.
7413 Are you crazy? Don't even think about adjusting these unless
7414 you understand the algorithms in comm_select.c first!
7417 NAME: incoming_dns_average
7420 LOC: Config.comm_incoming.dns.average
7422 Heavy voodoo here. I can't even believe you are reading this.
7423 Are you crazy? Don't even think about adjusting these unless
7424 you understand the algorithms in comm_select.c first!
7427 NAME: min_udp_poll_cnt min_icp_poll_cnt
7430 LOC: Config.comm_incoming.udp.min_poll
7432 Heavy voodoo here. I can't even believe you are reading this.
7433 Are you crazy? Don't even think about adjusting these unless
7434 you understand the algorithms in comm_select.c first!
7437 NAME: min_dns_poll_cnt
7440 LOC: Config.comm_incoming.dns.min_poll
7442 Heavy voodoo here. I can't even believe you are reading this.
7443 Are you crazy? Don't even think about adjusting these unless
7444 you understand the algorithms in comm_select.c first!
7447 NAME: min_tcp_poll_cnt min_http_poll_cnt
7450 LOC: Config.comm_incoming.tcp.min_poll
7452 Heavy voodoo here. I can't even believe you are reading this.
7453 Are you crazy? Don't even think about adjusting these unless
7454 you understand the algorithms in comm_select.c first!
7460 LOC: Config.accept_filter
7464 The name of an accept(2) filter to install on Squid's
7465 listen socket(s). This feature is perhaps specific to
7466 FreeBSD and requires support in the kernel.
7468 The 'httpready' filter delays delivering new connections
7469 to Squid until a full HTTP request has been received.
7470 See the accf_http(9) man page for details.
7472 The 'dataready' filter delays delivering new connections
7473 to Squid until there is some data to process.
7474 See the accf_dataready(9) man page for details.
7478 The 'data' filter delays delivering of new connections
7479 to Squid until there is some data to process by TCP_ACCEPT_DEFER.
7480 You may optionally specify a number of seconds to wait by
7481 'data=N' where N is the number of seconds. Defaults to 30
7482 if not specified. See the tcp(7) man page for details.
7485 accept_filter httpready
7490 NAME: client_ip_max_connections
7492 LOC: Config.client_ip_max_connections
7494 DEFAULT_DOC: No limit.
7496 Set an absolute limit on the number of connections a single
7497 client IP can use. Any more than this and Squid will begin to drop
7498 new connections from the client until it closes some links.
7500 Note that this is a global limit. It affects all HTTP, HTCP, Gopher and FTP
7501 connections from the client. For finer control use the ACL access controls.
7503 Requires client_db to be enabled (the default).
7505 WARNING: This may noticably slow down traffic received via external proxies
7506 or NAT devices and cause them to rebound error messages back to their clients.
7509 NAME: tcp_recv_bufsize
7513 DEFAULT_DOC: Use operating system TCP defaults.
7514 LOC: Config.tcpRcvBufsz
7516 Size of receive buffer to set for TCP sockets. Probably just
7517 as easy to change your kernel's default.
7518 Omit from squid.conf to use the default buffer size.
7523 -----------------------------------------------------------------------------
7530 LOC: Adaptation::Icap::TheConfig.onoff
7533 If you want to enable the ICAP module support, set this to on.
7536 NAME: icap_connect_timeout
7539 LOC: Adaptation::Icap::TheConfig.connect_timeout_raw
7542 This parameter specifies how long to wait for the TCP connect to
7543 the requested ICAP server to complete before giving up and either
7544 terminating the HTTP transaction or bypassing the failure.
7546 The default for optional services is peer_connect_timeout.
7547 The default for essential services is connect_timeout.
7548 If this option is explicitly set, its value applies to all services.
7551 NAME: icap_io_timeout
7555 DEFAULT_DOC: Use read_timeout.
7556 LOC: Adaptation::Icap::TheConfig.io_timeout_raw
7559 This parameter specifies how long to wait for an I/O activity on
7560 an established, active ICAP connection before giving up and
7561 either terminating the HTTP transaction or bypassing the
7565 NAME: icap_service_failure_limit
7566 COMMENT: limit [in memory-depth time-units]
7567 TYPE: icap_service_failure_limit
7569 LOC: Adaptation::Icap::TheConfig
7572 The limit specifies the number of failures that Squid tolerates
7573 when establishing a new TCP connection with an ICAP service. If
7574 the number of failures exceeds the limit, the ICAP service is
7575 not used for new ICAP requests until it is time to refresh its
7578 A negative value disables the limit. Without the limit, an ICAP
7579 service will not be considered down due to connectivity failures
7580 between ICAP OPTIONS requests.
7582 Squid forgets ICAP service failures older than the specified
7583 value of memory-depth. The memory fading algorithm
7584 is approximate because Squid does not remember individual
7585 errors but groups them instead, splitting the option
7586 value into ten time slots of equal length.
7588 When memory-depth is 0 and by default this option has no
7589 effect on service failure expiration.
7591 Squid always forgets failures when updating service settings
7592 using an ICAP OPTIONS transaction, regardless of this option
7596 # suspend service usage after 10 failures in 5 seconds:
7597 icap_service_failure_limit 10 in 5 seconds
7600 NAME: icap_service_revival_delay
7603 LOC: Adaptation::Icap::TheConfig.service_revival_delay
7606 The delay specifies the number of seconds to wait after an ICAP
7607 OPTIONS request failure before requesting the options again. The
7608 failed ICAP service is considered "down" until fresh OPTIONS are
7611 The actual delay cannot be smaller than the hardcoded minimum
7612 delay of 30 seconds.
7615 NAME: icap_preview_enable
7619 LOC: Adaptation::Icap::TheConfig.preview_enable
7622 The ICAP Preview feature allows the ICAP server to handle the
7623 HTTP message by looking only at the beginning of the message body
7624 or even without receiving the body at all. In some environments,
7625 previews greatly speedup ICAP processing.
7627 During an ICAP OPTIONS transaction, the server may tell Squid what
7628 HTTP messages should be previewed and how big the preview should be.
7629 Squid will not use Preview if the server did not request one.
7631 To disable ICAP Preview for all ICAP services, regardless of
7632 individual ICAP server OPTIONS responses, set this option to "off".
7634 icap_preview_enable off
7637 NAME: icap_preview_size
7640 LOC: Adaptation::Icap::TheConfig.preview_size
7642 DEFAULT_DOC: No preview sent.
7644 The default size of preview data to be sent to the ICAP server.
7645 This value might be overwritten on a per server basis by OPTIONS requests.
7648 NAME: icap_206_enable
7652 LOC: Adaptation::Icap::TheConfig.allow206_enable
7655 206 (Partial Content) responses is an ICAP extension that allows the
7656 ICAP agents to optionally combine adapted and original HTTP message
7657 content. The decision to combine is postponed until the end of the
7658 ICAP response. Squid supports Partial Content extension by default.
7660 Activation of the Partial Content extension is negotiated with each
7661 ICAP service during OPTIONS exchange. Most ICAP servers should handle
7662 negotation correctly even if they do not support the extension, but
7663 some might fail. To disable Partial Content support for all ICAP
7664 services and to avoid any negotiation, set this option to "off".
7670 NAME: icap_default_options_ttl
7673 LOC: Adaptation::Icap::TheConfig.default_options_ttl
7676 The default TTL value for ICAP OPTIONS responses that don't have
7677 an Options-TTL header.
7680 NAME: icap_persistent_connections
7684 LOC: Adaptation::Icap::TheConfig.reuse_connections
7687 Whether or not Squid should use persistent connections to
7691 NAME: adaptation_send_client_ip icap_send_client_ip
7693 IFDEF: USE_ADAPTATION
7695 LOC: Adaptation::Config::send_client_ip
7698 If enabled, Squid shares HTTP client IP information with adaptation
7699 services. For ICAP, Squid adds the X-Client-IP header to ICAP requests.
7700 For eCAP, Squid sets the libecap::metaClientIp transaction option.
7702 See also: adaptation_uses_indirect_client
7705 NAME: adaptation_send_username icap_send_client_username
7707 IFDEF: USE_ADAPTATION
7709 LOC: Adaptation::Config::send_username
7712 This sends authenticated HTTP client username (if available) to
7713 the adaptation service.
7715 For ICAP, the username value is encoded based on the
7716 icap_client_username_encode option and is sent using the header
7717 specified by the icap_client_username_header option.
7720 NAME: icap_client_username_header
7723 LOC: Adaptation::Icap::TheConfig.client_username_header
7724 DEFAULT: X-Client-Username
7726 ICAP request header name to use for adaptation_send_username.
7729 NAME: icap_client_username_encode
7733 LOC: Adaptation::Icap::TheConfig.client_username_encode
7736 Whether to base64 encode the authenticated client username.
7740 TYPE: icap_service_type
7742 LOC: Adaptation::Icap::TheConfig
7745 Defines a single ICAP service using the following format:
7747 icap_service id vectoring_point uri [option ...]
7750 an opaque identifier or name which is used to direct traffic to
7751 this specific service. Must be unique among all adaptation
7752 services in squid.conf.
7754 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
7755 This specifies at which point of transaction processing the
7756 ICAP service should be activated. *_postcache vectoring points
7757 are not yet supported.
7759 uri: icap://servername:port/servicepath
7760 ICAP server and service location.
7762 ICAP does not allow a single service to handle both REQMOD and RESPMOD
7763 transactions. Squid does not enforce that requirement. You can specify
7764 services with the same service_url and different vectoring_points. You
7765 can even specify multiple identical services as long as their
7766 service_names differ.
7768 To activate a service, use the adaptation_access directive. To group
7769 services, use adaptation_service_chain and adaptation_service_set.
7771 Service options are separated by white space. ICAP services support
7772 the following name=value options:
7775 If set to 'on' or '1', the ICAP service is treated as
7776 optional. If the service cannot be reached or malfunctions,
7777 Squid will try to ignore any errors and process the message as
7778 if the service was not enabled. No all ICAP errors can be
7779 bypassed. If set to 0, the ICAP service is treated as
7780 essential and all ICAP errors will result in an error page
7781 returned to the HTTP client.
7783 Bypass is off by default: services are treated as essential.
7786 If set to 'on' or '1', the ICAP service is allowed to
7787 dynamically change the current message adaptation plan by
7788 returning a chain of services to be used next. The services
7789 are specified using the X-Next-Services ICAP response header
7790 value, formatted as a comma-separated list of service names.
7791 Each named service should be configured in squid.conf. Other
7792 services are ignored. An empty X-Next-Services value results
7793 in an empty plan which ends the current adaptation.
7795 Dynamic adaptation plan may cross or cover multiple supported
7796 vectoring points in their natural processing order.
7798 Routing is not allowed by default: the ICAP X-Next-Services
7799 response header is ignored.
7802 Only has effect on split-stack systems. The default on those systems
7803 is to use IPv4-only connections. When set to 'on' this option will
7804 make Squid use IPv6-only connections to contact this ICAP service.
7806 on-overload=block|bypass|wait|force
7807 If the service Max-Connections limit has been reached, do
7808 one of the following for each new ICAP transaction:
7809 * block: send an HTTP error response to the client
7810 * bypass: ignore the "over-connected" ICAP service
7811 * wait: wait (in a FIFO queue) for an ICAP connection slot
7812 * force: proceed, ignoring the Max-Connections limit
7814 In SMP mode with N workers, each worker assumes the service
7815 connection limit is Max-Connections/N, even though not all
7816 workers may use a given service.
7818 The default value is "bypass" if service is bypassable,
7819 otherwise it is set to "wait".
7823 Use the given number as the Max-Connections limit, regardless
7824 of the Max-Connections value given by the service, if any.
7826 Older icap_service format without optional named parameters is
7827 deprecated but supported for backward compatibility.
7830 icap_service svcBlocker reqmod_precache icap://icap1.mydomain.net:1344/reqmod bypass=0
7831 icap_service svcLogger reqmod_precache icap://icap2.mydomain.net:1344/respmod routing=on
7835 TYPE: icap_class_type
7840 This deprecated option was documented to define an ICAP service
7841 chain, even though it actually defined a set of similar, redundant
7842 services, and the chains were not supported.
7844 To define a set of redundant services, please use the
7845 adaptation_service_set directive. For service chains, use
7846 adaptation_service_chain.
7850 TYPE: icap_access_type
7855 This option is deprecated. Please use adaptation_access, which
7856 has the same ICAP functionality, but comes with better
7857 documentation, and eCAP support.
7862 -----------------------------------------------------------------------------
7869 LOC: Adaptation::Ecap::TheConfig.onoff
7872 Controls whether eCAP support is enabled.
7876 TYPE: ecap_service_type
7878 LOC: Adaptation::Ecap::TheConfig
7881 Defines a single eCAP service
7883 ecap_service id vectoring_point uri [option ...]
7886 an opaque identifier or name which is used to direct traffic to
7887 this specific service. Must be unique among all adaptation
7888 services in squid.conf.
7890 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
7891 This specifies at which point of transaction processing the
7892 eCAP service should be activated. *_postcache vectoring points
7893 are not yet supported.
7895 uri: ecap://vendor/service_name?custom&cgi=style¶meters=optional
7896 Squid uses the eCAP service URI to match this configuration
7897 line with one of the dynamically loaded services. Each loaded
7898 eCAP service must have a unique URI. Obtain the right URI from
7899 the service provider.
7901 To activate a service, use the adaptation_access directive. To group
7902 services, use adaptation_service_chain and adaptation_service_set.
7904 Service options are separated by white space. eCAP services support
7905 the following name=value options:
7908 If set to 'on' or '1', the eCAP service is treated as optional.
7909 If the service cannot be reached or malfunctions, Squid will try
7910 to ignore any errors and process the message as if the service
7911 was not enabled. No all eCAP errors can be bypassed.
7912 If set to 'off' or '0', the eCAP service is treated as essential
7913 and all eCAP errors will result in an error page returned to the
7916 Bypass is off by default: services are treated as essential.
7919 If set to 'on' or '1', the eCAP service is allowed to
7920 dynamically change the current message adaptation plan by
7921 returning a chain of services to be used next.
7923 Dynamic adaptation plan may cross or cover multiple supported
7924 vectoring points in their natural processing order.
7926 Routing is not allowed by default.
7928 Older ecap_service format without optional named parameters is
7929 deprecated but supported for backward compatibility.
7933 ecap_service s1 reqmod_precache ecap://filters.R.us/leakDetector?on_error=block bypass=off
7934 ecap_service s2 respmod_precache ecap://filters.R.us/virusFilter config=/etc/vf.cfg bypass=on
7937 NAME: loadable_modules
7939 IFDEF: USE_LOADABLE_MODULES
7940 LOC: Config.loadable_module_names
7943 Instructs Squid to load the specified dynamic module(s) or activate
7944 preloaded module(s).
7946 loadable_modules @DEFAULT_PREFIX@/lib/MinimalAdapter.so
7950 MESSAGE ADAPTATION OPTIONS
7951 -----------------------------------------------------------------------------
7954 NAME: adaptation_service_set
7955 TYPE: adaptation_service_set_type
7956 IFDEF: USE_ADAPTATION
7961 Configures an ordered set of similar, redundant services. This is
7962 useful when hot standby or backup adaptation servers are available.
7964 adaptation_service_set set_name service_name1 service_name2 ...
7966 The named services are used in the set declaration order. The first
7967 applicable adaptation service from the set is used first. The next
7968 applicable service is tried if and only if the transaction with the
7969 previous service fails and the message waiting to be adapted is still
7972 When adaptation starts, broken services are ignored as if they were
7973 not a part of the set. A broken service is a down optional service.
7975 The services in a set must be attached to the same vectoring point
7976 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
7978 If all services in a set are optional then adaptation failures are
7979 bypassable. If all services in the set are essential, then a
7980 transaction failure with one service may still be retried using
7981 another service from the set, but when all services fail, the master
7982 transaction fails as well.
7984 A set may contain a mix of optional and essential services, but that
7985 is likely to lead to surprising results because broken services become
7986 ignored (see above), making previously bypassable failures fatal.
7987 Technically, it is the bypassability of the last failed service that
7990 See also: adaptation_access adaptation_service_chain
7993 adaptation_service_set svcBlocker urlFilterPrimary urlFilterBackup
7994 adaptation service_set svcLogger loggerLocal loggerRemote
7997 NAME: adaptation_service_chain
7998 TYPE: adaptation_service_chain_type
7999 IFDEF: USE_ADAPTATION
8004 Configures a list of complementary services that will be applied
8005 one-by-one, forming an adaptation chain or pipeline. This is useful
8006 when Squid must perform different adaptations on the same message.
8008 adaptation_service_chain chain_name service_name1 svc_name2 ...
8010 The named services are used in the chain declaration order. The first
8011 applicable adaptation service from the chain is used first. The next
8012 applicable service is applied to the successful adaptation results of
8013 the previous service in the chain.
8015 When adaptation starts, broken services are ignored as if they were
8016 not a part of the chain. A broken service is a down optional service.
8018 Request satisfaction terminates the adaptation chain because Squid
8019 does not currently allow declaration of RESPMOD services at the
8020 "reqmod_precache" vectoring point (see icap_service or ecap_service).
8022 The services in a chain must be attached to the same vectoring point
8023 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
8025 A chain may contain a mix of optional and essential services. If an
8026 essential adaptation fails (or the failure cannot be bypassed for
8027 other reasons), the master transaction fails. Otherwise, the failure
8028 is bypassed as if the failed adaptation service was not in the chain.
8030 See also: adaptation_access adaptation_service_set
8033 adaptation_service_chain svcRequest requestLogger urlFilter leakDetector
8036 NAME: adaptation_access
8037 TYPE: adaptation_access_type
8038 IFDEF: USE_ADAPTATION
8041 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
8043 Sends an HTTP transaction to an ICAP or eCAP adaptation service.
8045 adaptation_access service_name allow|deny [!]aclname...
8046 adaptation_access set_name allow|deny [!]aclname...
8048 At each supported vectoring point, the adaptation_access
8049 statements are processed in the order they appear in this
8050 configuration file. Statements pointing to the following services
8051 are ignored (i.e., skipped without checking their ACL):
8053 - services serving different vectoring points
8054 - "broken-but-bypassable" services
8055 - "up" services configured to ignore such transactions
8056 (e.g., based on the ICAP Transfer-Ignore header).
8058 When a set_name is used, all services in the set are checked
8059 using the same rules, to find the first applicable one. See
8060 adaptation_service_set for details.
8062 If an access list is checked and there is a match, the
8063 processing stops: For an "allow" rule, the corresponding
8064 adaptation service is used for the transaction. For a "deny"
8065 rule, no adaptation service is activated.
8067 It is currently not possible to apply more than one adaptation
8068 service at the same vectoring point to the same HTTP transaction.
8070 See also: icap_service and ecap_service
8073 adaptation_access service_1 allow all
8076 NAME: adaptation_service_iteration_limit
8078 IFDEF: USE_ADAPTATION
8079 LOC: Adaptation::Config::service_iteration_limit
8082 Limits the number of iterations allowed when applying adaptation
8083 services to a message. If your longest adaptation set or chain
8084 may have more than 16 services, increase the limit beyond its
8085 default value of 16. If detecting infinite iteration loops sooner
8086 is critical, make the iteration limit match the actual number
8087 of services in your longest adaptation set or chain.
8089 Infinite adaptation loops are most likely with routing services.
8091 See also: icap_service routing=1
8094 NAME: adaptation_masterx_shared_names
8096 IFDEF: USE_ADAPTATION
8097 LOC: Adaptation::Config::masterx_shared_name
8100 For each master transaction (i.e., the HTTP request and response
8101 sequence, including all related ICAP and eCAP exchanges), Squid
8102 maintains a table of metadata. The table entries are (name, value)
8103 pairs shared among eCAP and ICAP exchanges. The table is destroyed
8104 with the master transaction.
8106 This option specifies the table entry names that Squid must accept
8107 from and forward to the adaptation transactions.
8109 An ICAP REQMOD or RESPMOD transaction may set an entry in the
8110 shared table by returning an ICAP header field with a name
8111 specified in adaptation_masterx_shared_names.
8113 An eCAP REQMOD or RESPMOD transaction may set an entry in the
8114 shared table by implementing the libecap::visitEachOption() API
8115 to provide an option with a name specified in
8116 adaptation_masterx_shared_names.
8118 Squid will store and forward the set entry to subsequent adaptation
8119 transactions within the same master transaction scope.
8121 Only one shared entry name is supported at this time.
8124 # share authentication information among ICAP services
8125 adaptation_masterx_shared_names X-Subscriber-ID
8128 NAME: adaptation_meta
8130 IFDEF: USE_ADAPTATION
8131 LOC: Adaptation::Config::metaHeaders
8134 This option allows Squid administrator to add custom ICAP request
8135 headers or eCAP options to Squid ICAP requests or eCAP transactions.
8136 Use it to pass custom authentication tokens and other
8137 transaction-state related meta information to an ICAP/eCAP service.
8139 The addition of a meta header is ACL-driven:
8140 adaptation_meta name value [!]aclname ...
8142 Processing for a given header name stops after the first ACL list match.
8143 Thus, it is impossible to add two headers with the same name. If no ACL
8144 lists match for a given header name, no such header is added. For
8147 # do not debug transactions except for those that need debugging
8148 adaptation_meta X-Debug 1 needs_debugging
8150 # log all transactions except for those that must remain secret
8151 adaptation_meta X-Log 1 !keep_secret
8153 # mark transactions from users in the "G 1" group
8154 adaptation_meta X-Authenticated-Groups "G 1" authed_as_G1
8156 The "value" parameter may be a regular squid.conf token or a "double
8157 quoted string". Within the quoted string, use backslash (\) to escape
8158 any character, which is currently only useful for escaping backslashes
8159 and double quotes. For example,
8160 "this string has one backslash (\\) and two \"quotes\""
8162 Used adaptation_meta header values may be logged via %note
8163 logformat code. If multiple adaptation_meta headers with the same name
8164 are used during master transaction lifetime, the header values are
8165 logged in the order they were used and duplicate values are ignored
8166 (only the first repeated value will be logged).
8172 LOC: Adaptation::Icap::TheConfig.repeat
8173 DEFAULT_IF_NONE: deny all
8175 This ACL determines which retriable ICAP transactions are
8176 retried. Transactions that received a complete ICAP response
8177 and did not have to consume or produce HTTP bodies to receive
8178 that response are usually retriable.
8180 icap_retry allow|deny [!]aclname ...
8182 Squid automatically retries some ICAP I/O timeouts and errors
8183 due to persistent connection race conditions.
8185 See also: icap_retry_limit
8188 NAME: icap_retry_limit
8191 LOC: Adaptation::Icap::TheConfig.repeat_limit
8193 DEFAULT_DOC: No retries are allowed.
8195 Limits the number of retries allowed.
8197 Communication errors due to persistent connection race
8198 conditions are unavoidable, automatically retried, and do not
8199 count against this limit.
8201 See also: icap_retry
8207 -----------------------------------------------------------------------------
8210 NAME: check_hostnames
8213 LOC: Config.onoff.check_hostnames
8215 For security and stability reasons Squid can check
8216 hostnames for Internet standard RFC compliance. If you want
8217 Squid to perform these checks turn this directive on.
8220 NAME: allow_underscore
8223 LOC: Config.onoff.allow_underscore
8225 Underscore characters is not strictly allowed in Internet hostnames
8226 but nevertheless used by many sites. Set this to off if you want
8227 Squid to be strict about the standard.
8228 This check is performed only when check_hostnames is set to on.
8231 NAME: cache_dns_program
8233 IFDEF: USE_DNSHELPER
8234 DEFAULT: @DEFAULT_DNSSERVER@
8235 LOC: Config.Program.dnsserver
8237 Specify the location of the executable for dnslookup process.
8241 TYPE: HelperChildConfig
8242 IFDEF: USE_DNSHELPER
8243 DEFAULT: 32 startup=1 idle=1
8244 LOC: Config.dnsChildren
8246 The maximum number of processes spawn to service DNS name lookups.
8247 If you limit it too few Squid will have to wait for them to process
8248 a backlog of requests, slowing it down. If you allow too many they
8249 will use RAM and other system resources noticably.
8250 The maximum this may be safely set to is 32.
8252 The startup= and idle= options allow some measure of skew in your
8257 Sets a minimum of how many processes are to be spawned when Squid
8258 starts or reconfigures. When set to zero the first request will
8259 cause spawning of the first child process to handle it.
8261 Starting too few will cause an initial slowdown in traffic as Squid
8262 attempts to simultaneously spawn enough processes to cope.
8266 Sets a minimum of how many processes Squid is to try and keep available
8267 at all times. When traffic begins to rise above what the existing
8268 processes can handle this many more will be spawned up to the maximum
8269 configured. A minimum setting of 1 is required.
8272 NAME: dns_retransmit_interval
8275 LOC: Config.Timeout.idns_retransmit
8276 IFDEF: !USE_DNSHELPER
8278 Initial retransmit interval for DNS queries. The interval is
8279 doubled each time all configured DNS servers have been tried.
8285 LOC: Config.Timeout.idns_query
8286 IFDEF: !USE_DNSHELPER
8288 DNS Query timeout. If no response is received to a DNS query
8289 within this time all DNS servers for the queried domain
8290 are assumed to be unavailable.
8293 NAME: dns_packet_max
8295 DEFAULT_DOC: EDNS disabled
8297 LOC: Config.dns.packet_max
8298 IFDEF: !USE_DNSHELPER
8300 Maximum number of bytes packet size to advertise via EDNS.
8301 Set to "none" to disable EDNS large packet support.
8303 For legacy reasons DNS UDP replies will default to 512 bytes which
8304 is too small for many responses. EDNS provides a means for Squid to
8305 negotiate receiving larger responses back immediately without having
8306 to failover with repeat requests. Responses larger than this limit
8307 will retain the old behaviour of failover to TCP DNS.
8309 Squid has no real fixed limit internally, but allowing packet sizes
8310 over 1500 bytes requires network jumbogram support and is usually not
8313 WARNING: The RFC also indicates that some older resolvers will reply
8314 with failure of the whole request if the extension is added. Some
8315 resolvers have already been identified which will reply with mangled
8316 EDNS response on occasion. Usually in response to many-KB jumbogram
8317 sizes being advertised by Squid.
8318 Squid will currently treat these both as an unable-to-resolve domain
8319 even if it would be resolvable without EDNS.
8326 DEFAULT_DOC: Search for single-label domain names is disabled.
8327 LOC: Config.onoff.res_defnames
8329 Normally the RES_DEFNAMES resolver option is disabled
8330 (see res_init(3)). This prevents caches in a hierarchy
8331 from interpreting single-component hostnames locally. To allow
8332 Squid to handle single-component names, enable this option.
8335 NAME: dns_nameservers
8338 DEFAULT_DOC: Use operating system definitions
8339 LOC: Config.dns_nameservers
8341 Use this if you want to specify a list of DNS name servers
8342 (IP addresses) to use instead of those given in your
8343 /etc/resolv.conf file.
8345 On Windows platforms, if no value is specified here or in
8346 the /etc/resolv.conf file, the list of DNS name servers are
8347 taken from the Windows registry, both static and dynamic DHCP
8348 configurations are supported.
8350 Example: dns_nameservers 10.0.0.1 192.172.0.4
8355 DEFAULT: @DEFAULT_HOSTS@
8356 LOC: Config.etcHostsPath
8358 Location of the host-local IP name-address associations
8359 database. Most Operating Systems have such a file on different
8361 - Un*X & Linux: /etc/hosts
8362 - Windows NT/2000: %SystemRoot%\system32\drivers\etc\hosts
8363 (%SystemRoot% value install default is c:\winnt)
8364 - Windows XP/2003: %SystemRoot%\system32\drivers\etc\hosts
8365 (%SystemRoot% value install default is c:\windows)
8366 - Windows 9x/Me: %windir%\hosts
8367 (%windir% value is usually c:\windows)
8368 - Cygwin: /etc/hosts
8370 The file contains newline-separated definitions, in the
8371 form ip_address_in_dotted_form name [name ...] names are
8372 whitespace-separated. Lines beginning with an hash (#)
8373 character are comments.
8375 The file is checked at startup and upon configuration.
8376 If set to 'none', it won't be checked.
8377 If append_domain is used, that domain will be added to
8378 domain-local (i.e. not containing any dot character) host
8384 LOC: Config.appendDomain
8386 DEFAULT_DOC: Use operating system definitions
8388 Appends local domain name to hostnames without any dots in
8389 them. append_domain must begin with a period.
8391 Be warned there are now Internet names with no dots in
8392 them using only top-domain names, so setting this may
8393 cause some Internet sites to become unavailable.
8396 append_domain .yourdomain.com
8399 NAME: ignore_unknown_nameservers
8401 LOC: Config.onoff.ignore_unknown_nameservers
8403 IFDEF: !USE_DNSHELPER
8405 By default Squid checks that DNS responses are received
8406 from the same IP addresses they are sent to. If they
8407 don't match, Squid ignores the response and writes a warning
8408 message to cache.log. You can allow responses from unknown
8409 nameservers by setting this option to 'off'.
8415 LOC: Config.dns.v4_first
8416 IFDEF: !USE_DNSHELPER
8418 With the IPv6 Internet being as fast or faster than IPv4 Internet
8419 for most networks Squid prefers to contact websites over IPv6.
8421 This option reverses the order of preference to make Squid contact
8422 dual-stack websites over IPv4 first. Squid will still perform both
8423 IPv6 and IPv4 DNS lookups before connecting.
8426 This option will restrict the situations under which IPv6
8427 connectivity is used (and tested). Hiding network problems
8428 which would otherwise be detected and warned about.
8432 COMMENT: (number of entries)
8435 LOC: Config.ipcache.size
8437 Maximum number of DNS IP cache entries.
8444 LOC: Config.ipcache.low
8451 LOC: Config.ipcache.high
8453 The size, low-, and high-water marks for the IP cache.
8456 NAME: fqdncache_size
8457 COMMENT: (number of entries)
8460 LOC: Config.fqdncache.size
8462 Maximum number of FQDN cache entries.
8467 -----------------------------------------------------------------------------
8470 NAME: configuration_includes_quoted_values
8474 LOC: ConfigParser::RecognizeQuotedValues
8476 If set, Squid will recognize each "quoted string" after a configuration
8477 directive as a single parameter. The quotes are stripped before the
8478 parameter value is interpreted or used.
8479 See "Values with spaces, quotes, and other special characters"
8480 section for more details.
8487 LOC: Config.onoff.mem_pools
8489 If set, Squid will keep pools of allocated (but unused) memory
8490 available for future use. If memory is a premium on your
8491 system and you believe your malloc library outperforms Squid
8492 routines, disable this.
8495 NAME: memory_pools_limit
8499 LOC: Config.MemPools.limit
8501 Used only with memory_pools on:
8502 memory_pools_limit 50 MB
8504 If set to a non-zero value, Squid will keep at most the specified
8505 limit of allocated (but unused) memory in memory pools. All free()
8506 requests that exceed this limit will be handled by your malloc
8507 library. Squid does not pre-allocate any memory, just safe-keeps
8508 objects that otherwise would be free()d. Thus, it is safe to set
8509 memory_pools_limit to a reasonably high value even if your
8510 configuration will use less memory.
8512 If set to none, Squid will keep all memory it can. That is, there
8513 will be no limit on the total amount of memory used for safe-keeping.
8515 To disable memory allocation optimization, do not set
8516 memory_pools_limit to 0 or none. Set memory_pools to "off" instead.
8518 An overhead for maintaining memory pools is not taken into account
8519 when the limit is checked. This overhead is close to four bytes per
8520 object kept. However, pools may actually _save_ memory because of
8521 reduced memory thrashing in your malloc library.
8525 COMMENT: on|off|transparent|truncate|delete
8528 LOC: opt_forwarded_for
8530 If set to "on", Squid will append your client's IP address
8531 in the HTTP requests it forwards. By default it looks like:
8533 X-Forwarded-For: 192.1.2.3
8535 If set to "off", it will appear as
8537 X-Forwarded-For: unknown
8539 If set to "transparent", Squid will not alter the
8540 X-Forwarded-For header in any way.
8542 If set to "delete", Squid will delete the entire
8543 X-Forwarded-For header.
8545 If set to "truncate", Squid will remove all existing
8546 X-Forwarded-For entries, and place the client IP as the sole entry.
8549 NAME: cachemgr_passwd
8550 TYPE: cachemgrpasswd
8552 DEFAULT_DOC: No password. Actions which require password are denied.
8553 LOC: Config.passwd_list
8555 Specify passwords for cachemgr operations.
8557 Usage: cachemgr_passwd password action action ...
8559 Some valid actions are (see cache manager menu for a full list):
8599 * Indicates actions which will not be performed without a
8600 valid password, others can be performed if not listed here.
8602 To disable an action, set the password to "disable".
8603 To allow performing an action without a password, set the
8606 Use the keyword "all" to set the same password for all actions.
8609 cachemgr_passwd secret shutdown
8610 cachemgr_passwd lesssssssecret info stats/objects
8611 cachemgr_passwd disable all
8618 LOC: Config.onoff.client_db
8620 If you want to disable collecting per-client statistics,
8621 turn off client_db here.
8624 NAME: refresh_all_ims
8628 LOC: Config.onoff.refresh_all_ims
8630 When you enable this option, squid will always check
8631 the origin server for an update when a client sends an
8632 If-Modified-Since request. Many browsers use IMS
8633 requests when the user requests a reload, and this
8634 ensures those clients receive the latest version.
8636 By default (off), squid may return a Not Modified response
8637 based on the age of the cached version.
8640 NAME: reload_into_ims
8641 IFDEF: USE_HTTP_VIOLATIONS
8645 LOC: Config.onoff.reload_into_ims
8647 When you enable this option, client no-cache or ``reload''
8648 requests will be changed to If-Modified-Since requests.
8649 Doing this VIOLATES the HTTP standard. Enabling this
8650 feature could make you liable for problems which it
8653 see also refresh_pattern for a more selective approach.
8656 NAME: connect_retries
8658 LOC: Config.connect_retries
8660 DEFAULT_DOC: Do not retry failed connections.
8662 This sets the maximum number of connection attempts made for each
8663 TCP connection. The connect_retries attempts must all still
8664 complete within the connection timeout period.
8666 The default is not to re-try if the first connection attempt fails.
8667 The (not recommended) maximum is 10 tries.
8669 A warning message will be generated if it is set to a too-high
8670 value and the configured value will be over-ridden.
8672 Note: These re-tries are in addition to forward_max_tries
8673 which limit how many different addresses may be tried to find
8677 NAME: retry_on_error
8679 LOC: Config.retry.onerror
8682 If set to ON Squid will automatically retry requests when
8683 receiving an error response with status 403 (Forbidden),
8684 500 (Internal Error), 501 or 503 (Service not available).
8685 Status 502 and 504 (Gateway errors) are always retried.
8687 This is mainly useful if you are in a complex cache hierarchy to
8688 work around access control errors.
8690 NOTE: This retry will attempt to find another working destination.
8691 Which is different from the server which just failed.
8694 NAME: as_whois_server
8696 LOC: Config.as_whois_server
8697 DEFAULT: whois.ra.net
8699 WHOIS server to query for AS numbers. NOTE: AS numbers are
8700 queried only when Squid starts up, not for every request.
8705 LOC: Config.onoff.offline
8708 Enable this option and Squid will never try to validate cached
8712 NAME: uri_whitespace
8713 TYPE: uri_whitespace
8714 LOC: Config.uri_whitespace
8717 What to do with requests that have whitespace characters in the
8720 strip: The whitespace characters are stripped out of the URL.
8721 This is the behavior recommended by RFC2396 and RFC3986
8722 for tolerant handling of generic URI.
8723 NOTE: This is one difference between generic URI and HTTP URLs.
8725 deny: The request is denied. The user receives an "Invalid
8727 This is the behaviour recommended by RFC2616 for safe
8728 handling of HTTP request URL.
8730 allow: The request is allowed and the URI is not changed. The
8731 whitespace characters remain in the URI. Note the
8732 whitespace is passed to redirector processes if they
8734 Note this may be considered a violation of RFC2616
8735 request parsing where whitespace is prohibited in the
8738 encode: The request is allowed and the whitespace characters are
8739 encoded according to RFC1738.
8741 chop: The request is allowed and the URI is chopped at the
8745 NOTE the current Squid implementation of encode and chop violates
8746 RFC2616 by not using a 301 redirect after altering the URL.
8751 LOC: Config.chroot_dir
8754 Specifies a directory where Squid should do a chroot() while
8755 initializing. This also causes Squid to fully drop root
8756 privileges after initializing. This means, for example, if you
8757 use a HTTP port less than 1024 and try to reconfigure, you may
8758 get an error saying that Squid can not open the port.
8761 NAME: balance_on_multiple_ip
8763 LOC: Config.onoff.balance_on_multiple_ip
8766 Modern IP resolvers in squid sort lookup results by preferred access.
8767 By default squid will use these IP in order and only rotates to
8768 the next listed when the most preffered fails.
8770 Some load balancing servers based on round robin DNS have been
8771 found not to preserve user session state across requests
8772 to different IP addresses.
8774 Enabling this directive Squid rotates IP's per request.
8777 NAME: pipeline_prefetch
8778 TYPE: pipelinePrefetch
8779 LOC: Config.pipeline_max_prefetch
8781 DEFAULT_DOC: Do not pre-parse pipelined requests.
8783 HTTP clients may send a pipeline of 1+N requests to Squid using a
8784 single connection, without waiting for Squid to respond to the first
8785 of those requests. This option limits the number of concurrent
8786 requests Squid will try to handle in parallel. If set to N, Squid
8787 will try to receive and process up to 1+N requests on the same
8788 connection concurrently.
8790 Defaults to 0 (off) for bandwidth management and access logging
8793 NOTE: pipelining requires persistent connections to clients.
8795 WARNING: pipelining breaks NTLM and Negotiate/Kerberos authentication.
8798 NAME: high_response_time_warning
8801 LOC: Config.warnings.high_rptm
8803 DEFAULT_DOC: disabled.
8805 If the one-minute median response time exceeds this value,
8806 Squid prints a WARNING with debug level 0 to get the
8807 administrators attention. The value is in milliseconds.
8810 NAME: high_page_fault_warning
8812 LOC: Config.warnings.high_pf
8814 DEFAULT_DOC: disabled.
8816 If the one-minute average page fault rate exceeds this
8817 value, Squid prints a WARNING with debug level 0 to get
8818 the administrators attention. The value is in page faults
8822 NAME: high_memory_warning
8824 LOC: Config.warnings.high_memory
8826 DEFAULT_DOC: disabled.
8828 If the memory usage (as determined by mallinfo) exceeds
8829 this amount, Squid prints a WARNING with debug level 0 to get
8830 the administrators attention.
8833 NAME: sleep_after_fork
8834 COMMENT: (microseconds)
8836 LOC: Config.sleep_after_fork
8839 When this is set to a non-zero value, the main Squid process
8840 sleeps the specified number of microseconds after a fork()
8841 system call. This sleep may help the situation where your
8842 system reports fork() failures due to lack of (virtual)
8843 memory. Note, however, if you have a lot of child
8844 processes, these sleep delays will add up and your
8845 Squid will not service requests for some amount of time
8846 until all the child processes have been started.
8847 On Windows value less then 1000 (1 milliseconds) are
8851 NAME: windows_ipaddrchangemonitor
8852 IFDEF: _SQUID_WINDOWS_
8856 LOC: Config.onoff.WIN32_IpAddrChangeMonitor
8858 On Windows Squid by default will monitor IP address changes and will
8859 reconfigure itself after any detected event. This is very useful for
8860 proxies connected to internet with dial-up interfaces.
8861 In some cases (a Proxy server acting as VPN gateway is one) it could be
8862 desiderable to disable this behaviour setting this to 'off'.
8863 Note: after changing this, Squid service must be restarted.
8868 IFDEF: USE_SQUID_EUI
8870 LOC: Eui::TheConfig.euiLookup
8872 Whether to lookup the EUI or MAC address of a connected client.
8875 NAME: max_filedescriptors max_filedesc
8878 DEFAULT_DOC: Use operating system limits set by ulimit.
8879 LOC: Config.max_filedescriptors
8881 Reduce the maximum number of filedescriptors supported below
8882 the usual operating system defaults.
8884 Remove from squid.conf to inherit the current ulimit setting.
8886 Note: Changing this requires a restart of Squid. Also
8887 not all I/O types supports large values (eg on Windows).
8894 DEFAULT_DOC: SMP support disabled.
8896 Number of main Squid processes or "workers" to fork and maintain.
8897 0: "no daemon" mode, like running "squid -N ..."
8898 1: "no SMP" mode, start one main Squid process daemon (default)
8899 N: start N main Squid process daemons (i.e., SMP mode)
8901 In SMP mode, each worker does nearly all what a single Squid daemon
8902 does (e.g., listen on http_port and forward HTTP requests).
8905 NAME: cpu_affinity_map
8906 TYPE: CpuAffinityMap
8907 LOC: Config.cpuAffinityMap
8909 DEFAULT_DOC: Let operating system decide.
8911 Usage: cpu_affinity_map process_numbers=P1,P2,... cores=C1,C2,...
8913 Sets 1:1 mapping between Squid processes and CPU cores. For example,
8915 cpu_affinity_map process_numbers=1,2,3,4 cores=1,3,5,7
8917 affects processes 1 through 4 only and places them on the first
8918 four even cores, starting with core #1.
8920 CPU cores are numbered starting from 1. Requires support for
8921 sched_getaffinity(2) and sched_setaffinity(2) system calls.
8923 Multiple cpu_affinity_map options are merged.
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