2 # SQUID Web Proxy Cache http://www.squid-cache.org/
3 # ----------------------------------------------------------
5 # Squid is the result of efforts by numerous individuals from
6 # the Internet community; see the CONTRIBUTORS file for full
7 # details. Many organizations have provided support for Squid's
8 # development; see the SPONSORS file for full details. Squid is
9 # Copyrighted (C) 2000 by the Regents of the University of
10 # California; see the COPYRIGHT file for full details. Squid
11 # incorporates software developed and/or copyrighted by other
12 # sources; see the CREDITS file for full details.
14 # This program is free software; you can redistribute it and/or modify
15 # it under the terms of the GNU General Public License as published by
16 # the Free Software Foundation; either version 2 of the License, or
17 # (at your option) any later version.
19 # This program is distributed in the hope that it will be useful,
20 # but WITHOUT ANY WARRANTY; without even the implied warranty of
21 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 # GNU General Public License for more details.
24 # You should have received a copy of the GNU General Public License
25 # along with this program; if not, write to the Free Software
26 # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
31 ----------------------------
33 This is the documentation for the Squid configuration file.
34 This documentation can also be found online at:
35 http://www.squid-cache.org/Doc/config/
37 You may wish to look at the Squid home page and wiki for the
38 FAQ and other documentation:
39 http://www.squid-cache.org/
40 http://wiki.squid-cache.org/SquidFaq
41 http://wiki.squid-cache.org/ConfigExamples
43 This documentation shows what the defaults for various directives
44 happen to be. If you don't need to change the default, you should
45 leave the line out of your squid.conf in most cases.
47 In some cases "none" refers to no default setting at all,
48 while in other cases it refers to the value of the option
49 - the comments for that keyword indicate if this is the case.
54 Configuration options can be included using the "include" directive.
55 Include takes a list of files to include. Quoting and wildcards are
60 include /path/to/included/file/squid.acl.config
62 Includes can be nested up to a hard-coded depth of 16 levels.
63 This arbitrary restriction is to prevent recursive include references
64 from causing Squid entering an infinite loop whilst trying to load
67 Values with byte units
69 Squid accepts size units on some size related directives. All
70 such directives are documented with a default value displaying
73 Units accepted by Squid are:
75 KB - Kilobyte (1024 bytes)
79 Values with spaces, quotes, and other special characters
81 Squid supports directive parameters with spaces, quotes, and other
82 special characters. Surround such parameters with "double quotes". Use
83 the configuration_includes_quoted_values directive to enable or
86 Squid supports reading configuration option parameters from external
87 files using the syntax:
88 parameters("/path/filename")
90 acl whitelist dstdomain parameters("/etc/squid/whitelist.txt")
92 Conditional configuration
94 If-statements can be used to make configuration directives
98 ... regular configuration directives ...
100 ... regular configuration directives ...]
103 The else part is optional. The keywords "if", "else", and "endif"
104 must be typed on their own lines, as if they were regular
105 configuration directives.
107 NOTE: An else-if condition is not supported.
109 These individual conditions types are supported:
112 Always evaluates to true.
114 Always evaluates to false.
115 <integer> = <integer>
116 Equality comparison of two integer numbers.
121 The following SMP-related preprocessor macros can be used.
123 ${process_name} expands to the current Squid process "name"
124 (e.g., squid1, squid2, or cache1).
126 ${process_number} expands to the current Squid process
127 identifier, which is an integer number (e.g., 1, 2, 3) unique
128 across all Squid processes of the current service instance.
130 ${service_name} expands into the current Squid service instance
131 name identifier which is provided by -n on the command line.
135 # options still not yet ported from 2.7 to 3.x
136 NAME: broken_vary_encoding
139 This option is not yet supported by Squid-3.
145 This option is not yet supported by Squid-3.
151 This option is not yet supported by Squid-3.
154 NAME: external_refresh_check
157 This option is not yet supported by Squid-3.
160 NAME: location_rewrite_program location_rewrite_access location_rewrite_children location_rewrite_concurrency
163 This option is not yet supported by Squid-3.
166 NAME: refresh_stale_hit
169 This option is not yet supported by Squid-3.
172 # Options removed in 3.5
173 NAME: hierarchy_stoplist
176 Remove this line. Use always_direct or cache_peer_access ACLs instead if you need to prevent cache_peer use.
179 # Options Removed in 3.4
183 Remove this line. Use acls with access_log directives to control access logging
189 Remove this line. Use acls with icap_log directives to control icap logging
192 # Options Removed in 3.3
193 NAME: ignore_ims_on_miss
196 Remove this line. The HTTP/1.1 feature is now configured by 'cache_miss_revalidate'.
199 # Options Removed in 3.2
200 NAME: dns_v4_fallback
203 Remove this line. Squid performs a 'Happy Eyeballs' algorithm, the 'fallback' algorithm is no longer relevant.
206 NAME: emulate_httpd_log
209 Replace this with an access_log directive using the format 'common' or 'combined'.
215 Use a regular access.log with ACL limiting it to MISS events.
221 Remove this line. Configure FTP page display using the CSS controls in errorpages.css instead.
224 NAME: ignore_expect_100
227 Remove this line. The HTTP/1.1 feature is now fully supported by default.
233 Remove this option from your config. To log FQDN use %>A in the log format.
236 NAME: log_ip_on_direct
239 Remove this option from your config. To log server or peer names use %<A in the log format.
242 NAME: maximum_single_addr_tries
245 Replaced by connect_retries. The behaviour has changed, please read the documentation before altering.
248 NAME: referer_log referrer_log
251 Replace this with an access_log directive using the format 'referrer'.
257 Remove this line. The feature is supported by default in storage types where update is implemented.
260 NAME: url_rewrite_concurrency
263 Remove this line. Set the 'concurrency=' option of url_rewrite_children instead.
269 Replace this with an access_log directive using the format 'useragent'.
272 # Options Removed in 3.1
276 Remove this line. DNS is no longer tested on startup.
279 NAME: extension_methods
282 Remove this line. All valid methods for HTTP are accepted by default.
285 # 2.7 Options Removed/Replaced in 3.2
290 # 2.7 Options Removed/Replaced in 3.1
298 Remove this line. HTTP/1.1 is supported by default.
301 NAME: upgrade_http0.9
304 Remove this line. ICY/1.0 streaming protocol is supported by default.
307 NAME: zph_local zph_mode zph_option zph_parent zph_sibling
310 Alter these entries. Use the qos_flows directive instead.
313 # Options Removed in 3.0
317 Since squid-3.0 replace with request_header_access or reply_header_access
318 depending on whether you wish to match client requests or server replies.
321 NAME: httpd_accel_no_pmtu_disc
324 Since squid-3.0 use the 'disable-pmtu-discovery' flag on http_port instead.
327 NAME: wais_relay_host
330 Replace this line with 'cache_peer' configuration.
333 NAME: wais_relay_port
336 Replace this line with 'cache_peer' configuration.
340 OPTIONS FOR AUTHENTICATION
341 -----------------------------------------------------------------------------
350 This is used to define parameters for the various authentication
351 schemes supported by Squid.
353 format: auth_param scheme parameter [setting]
355 The order in which authentication schemes are presented to the client is
356 dependent on the order the scheme first appears in config file. IE
357 has a bug (it's not RFC 2617 compliant) in that it will use the basic
358 scheme if basic is the first entry presented, even if more secure
359 schemes are presented. For now use the order in the recommended
360 settings section below. If other browsers have difficulties (don't
361 recognize the schemes offered even if you are using basic) either
362 put basic first, or disable the other schemes (by commenting out their
365 Once an authentication scheme is fully configured, it can only be
366 shutdown by shutting squid down and restarting. Changes can be made on
367 the fly and activated with a reconfigure. I.E. You can change to a
368 different helper, but not unconfigure the helper completely.
370 Please note that while this directive defines how Squid processes
371 authentication it does not automatically activate authentication.
372 To use authentication you must in addition make use of ACLs based
373 on login name in http_access (proxy_auth, proxy_auth_regex or
374 external with %LOGIN used in the format tag). The browser will be
375 challenged for authentication on the first such acl encountered
376 in http_access processing and will also be re-challenged for new
377 login credentials if the request is being denied by a proxy_auth
380 WARNING: authentication can't be used in a transparently intercepting
381 proxy as the client then thinks it is talking to an origin server and
382 not the proxy. This is a limitation of bending the TCP/IP protocol to
383 transparently intercepting port 80, not a limitation in Squid.
384 Ports flagged 'transparent', 'intercept', or 'tproxy' have
385 authentication disabled.
387 === Parameters common to all schemes. ===
390 Specifies the command for the external authenticator.
392 By default, each authentication scheme is not used unless a
393 program is specified.
395 See http://wiki.squid-cache.org/Features/AddonHelpers for
396 more details on helper operations and creating your own.
399 Specifies a string to be append to request line format for
400 the authentication helper. "Quoted" format values may contain
401 spaces and logformat %macros. In theory, any logformat %macro
402 can be used. In practice, a %macro expands as a dash (-) if
403 the helper request is sent before the required macro
404 information is available to Squid.
406 By default, Squid uses request formats provided in
407 scheme-specific examples below (search for %credentials).
409 The expanded key_extras value is added to the Squid credentials
410 cache and, hence, will affect authentication. It can be used to
411 autenticate different users with identical user names (e.g.,
412 when user authentication depends on http_port).
414 Avoid adding frequently changing information to key_extras. For
415 example, if you add user source IP, and it changes frequently
416 in your environment, then max_user_ip ACL is going to treat
417 every user+IP combination as a unique "user", breaking the ACL
418 and wasting a lot of memory on those user records. It will also
419 force users to authenticate from scratch whenever their IP
423 Specifies the protection scope (aka realm name) which is to be
424 reported to the client for the authentication scheme. It is
425 commonly part of the text the user will see when prompted for
426 their username and password.
428 For Basic the default is "Squid proxy-caching web server".
429 For Digest there is no default, this parameter is mandatory.
430 For NTLM and Negotiate this parameter is ignored.
432 "children" numberofchildren [startup=N] [idle=N] [concurrency=N]
434 The maximum number of authenticator processes to spawn. If
435 you start too few Squid will have to wait for them to process
436 a backlog of credential verifications, slowing it down. When
437 password verifications are done via a (slow) network you are
438 likely to need lots of authenticator processes.
440 The startup= and idle= options permit some skew in the exact
441 amount run. A minimum of startup=N will begin during startup
442 and reconfigure. Squid will start more in groups of up to
443 idle=N in an attempt to meet traffic needs and to keep idle=N
444 free above those traffic needs up to the maximum.
446 The concurrency= option sets the number of concurrent requests
447 the helper can process. The default of 0 is used for helpers
448 who only supports one request at a time. Setting this to a
449 number greater than 0 changes the protocol used to include a
450 channel ID field first on the request/response line, allowing
451 multiple requests to be sent to the same helper in parallel
452 without waiting for the response.
454 Concurrency must not be set unless it's known the helper
455 supports the input format with channel-ID fields.
457 NOTE: NTLM and Negotiate schemes do not support concurrency
458 in the Squid code module even though some helpers can.
461 IF HAVE_AUTH_MODULE_BASIC
462 === Basic authentication parameters ===
465 HTTP uses iso-latin-1 as character set, while some
466 authentication backends such as LDAP expects UTF-8. If this is
467 set to on Squid will translate the HTTP iso-latin-1 charset to
468 UTF-8 before sending the username and password to the helper.
470 "credentialsttl" timetolive
471 Specifies how long squid assumes an externally validated
472 username:password pair is valid for - in other words how
473 often the helper program is called for that user. Set this
474 low to force revalidation with short lived passwords.
476 NOTE: setting this high does not impact your susceptibility
477 to replay attacks unless you are using an one-time password
478 system (such as SecureID). If you are using such a system,
479 you will be vulnerable to replay attacks unless you also
480 use the max_user_ip ACL in an http_access rule.
482 "casesensitive" on|off
483 Specifies if usernames are case sensitive. Most user databases
484 are case insensitive allowing the same username to be spelled
485 using both lower and upper case letters, but some are case
486 sensitive. This makes a big difference for user_max_ip ACL
487 processing and similar.
490 IF HAVE_AUTH_MODULE_DIGEST
491 === Digest authentication parameters ===
494 HTTP uses iso-latin-1 as character set, while some
495 authentication backends such as LDAP expects UTF-8. If this is
496 set to on Squid will translate the HTTP iso-latin-1 charset to
497 UTF-8 before sending the username and password to the helper.
499 "nonce_garbage_interval" timeinterval
500 Specifies the interval that nonces that have been issued
501 to client_agent's are checked for validity.
503 "nonce_max_duration" timeinterval
504 Specifies the maximum length of time a given nonce will be
507 "nonce_max_count" number
508 Specifies the maximum number of times a given nonce can be
511 "nonce_strictness" on|off
512 Determines if squid requires strict increment-by-1 behavior
513 for nonce counts, or just incrementing (off - for use when
514 user agents generate nonce counts that occasionally miss 1
515 (ie, 1,2,4,6)). Default off.
517 "check_nonce_count" on|off
518 This directive if set to off can disable the nonce count check
519 completely to work around buggy digest qop implementations in
520 certain mainstream browser versions. Default on to check the
521 nonce count to protect from authentication replay attacks.
523 "post_workaround" on|off
524 This is a workaround to certain buggy browsers who send an
525 incorrect request digest in POST requests when reusing the
526 same nonce as acquired earlier on a GET request.
529 IF HAVE_AUTH_MODULE_NEGOTIATE
530 === Negotiate authentication parameters ===
533 If you experience problems with PUT/POST requests when using
534 the this authentication scheme then you can try setting this
535 to off. This will cause Squid to forcibly close the connection
536 on the initial request where the browser asks which schemes
537 are supported by the proxy.
540 IF HAVE_AUTH_MODULE_NTLM
541 === NTLM authentication parameters ===
544 If you experience problems with PUT/POST requests when using
545 the this authentication scheme then you can try setting this
546 to off. This will cause Squid to forcibly close the connection
547 on the initial request where the browser asks which schemes
548 are supported by the proxy.
551 === Example Configuration ===
553 This configuration displays the recommended authentication scheme
554 order from most to least secure with recommended minimum configuration
555 settings for each scheme:
557 #auth_param negotiate program <uncomment and complete this line to activate>
558 #auth_param negotiate children 20 startup=0 idle=1
559 #auth_param negotiate keep_alive on
561 #auth_param digest program <uncomment and complete this line to activate>
562 #auth_param digest children 20 startup=0 idle=1
563 #auth_param digest realm Squid proxy-caching web server
564 #auth_param digest nonce_garbage_interval 5 minutes
565 #auth_param digest nonce_max_duration 30 minutes
566 #auth_param digest nonce_max_count 50
568 #auth_param ntlm program <uncomment and complete this line to activate>
569 #auth_param ntlm children 20 startup=0 idle=1
570 #auth_param ntlm keep_alive on
572 #auth_param basic program <uncomment and complete this line>
573 #auth_param basic children 5 startup=5 idle=1
574 #auth_param basic realm Squid proxy-caching web server
575 #auth_param basic credentialsttl 2 hours
578 NAME: authenticate_cache_garbage_interval
581 LOC: Config.authenticateGCInterval
583 The time period between garbage collection across the username cache.
584 This is a trade-off between memory utilization (long intervals - say
585 2 days) and CPU (short intervals - say 1 minute). Only change if you
589 NAME: authenticate_ttl
592 LOC: Config.authenticateTTL
594 The time a user & their credentials stay in the logged in
595 user cache since their last request. When the garbage
596 interval passes, all user credentials that have passed their
597 TTL are removed from memory.
600 NAME: authenticate_ip_ttl
602 LOC: Config.authenticateIpTTL
605 If you use proxy authentication and the 'max_user_ip' ACL,
606 this directive controls how long Squid remembers the IP
607 addresses associated with each user. Use a small value
608 (e.g., 60 seconds) if your users might change addresses
609 quickly, as is the case with dialup. You might be safe
610 using a larger value (e.g., 2 hours) in a corporate LAN
611 environment with relatively static address assignments.
616 -----------------------------------------------------------------------------
619 NAME: external_acl_type
620 TYPE: externalAclHelper
621 LOC: Config.externalAclHelperList
624 This option defines external acl classes using a helper program
625 to look up the status
627 external_acl_type name [options] FORMAT.. /path/to/helper [helper arguments..]
631 ttl=n TTL in seconds for cached results (defaults to 3600
634 TTL for cached negative lookups (default same
637 Maximum number of acl helper processes spawned to service
638 external acl lookups of this type. (default 20)
640 Minimum number of acl helper processes to spawn during
641 startup and reconfigure to service external acl lookups
642 of this type. (default 0)
644 Number of acl helper processes to keep ahead of traffic
645 loads. Squid will spawn this many at once whenever load
646 rises above the capabilities of existing processes.
647 Up to the value of children-max. (default 1)
648 concurrency=n concurrency level per process. Only used with helpers
649 capable of processing more than one query at a time.
650 cache=n limit the result cache size, default is 262144.
651 grace=n Percentage remaining of TTL where a refresh of a
652 cached entry should be initiated without needing to
653 wait for a new reply. (default is for no grace period)
654 protocol=2.5 Compatibility mode for Squid-2.5 external acl helpers
655 ipv4 / ipv6 IP protocol used to communicate with this helper.
656 The default is to auto-detect IPv6 and use it when available.
658 FORMAT specifications
660 %LOGIN Authenticated user login name
661 %EXT_USER Username from previous external acl
662 %EXT_LOG Log details from previous external acl
663 %EXT_TAG Tag from previous external acl
664 %IDENT Ident user name
666 %SRCPORT Client source port
669 %PROTO Requested URL scheme
671 %PATH Requested URL path
672 %METHOD Request method
673 %MYADDR Squid interface address
674 %MYPORT Squid http_port number
675 %PATH Requested URL-path (including query-string if any)
676 %USER_CERT SSL User certificate in PEM format
677 %USER_CERTCHAIN SSL User certificate chain in PEM format
678 %USER_CERT_xx SSL User certificate subject attribute xx
679 %USER_CA_CERT_xx SSL User certificate issuer attribute xx
681 %>{Header} HTTP request header "Header"
683 HTTP request header "Hdr" list member "member"
685 HTTP request header list member using ; as
686 list separator. ; can be any non-alphanumeric
689 %<{Header} HTTP reply header "Header"
691 HTTP reply header "Hdr" list member "member"
693 HTTP reply header list member using ; as
694 list separator. ; can be any non-alphanumeric
697 %ACL The name of the ACL being tested.
698 %DATA The ACL arguments. If not used then any arguments
699 is automatically added at the end of the line
701 NOTE: this will encode the arguments as one token,
702 whereas the default will pass each separately.
704 %% The percent sign. Useful for helpers which need
705 an unchanging input format.
708 General request syntax:
710 [channel-ID] FORMAT-values [acl-values ...]
713 FORMAT-values consists of transaction details expanded with
714 whitespace separation per the config file FORMAT specification
715 using the FORMAT macros listed above.
717 acl-values consists of any string specified in the referencing
718 config 'acl ... external' line. see the "acl external" directive.
720 Request values sent to the helper are URL escaped to protect
721 each value in requests against whitespaces.
723 If using protocol=2.5 then the request sent to the helper is not
724 URL escaped to protect against whitespace.
726 NOTE: protocol=3.0 is deprecated as no longer necessary.
728 When using the concurrency= option the protocol is changed by
729 introducing a query channel tag in front of the request/response.
730 The query channel tag is a number between 0 and concurrency-1.
731 This value must be echoed back unchanged to Squid as the first part
732 of the response relating to its request.
735 The helper receives lines expanded per the above format specification
736 and for each input line returns 1 line starting with OK/ERR/BH result
737 code and optionally followed by additional keywords with more details.
740 General result syntax:
742 [channel-ID] result keyword=value ...
744 Result consists of one of the codes:
747 the ACL test produced a match.
750 the ACL test does not produce a match.
753 An internal error occurred in the helper, preventing
754 a result being identified.
756 The meaning of 'a match' is determined by your squid.conf
757 access control configuration. See the Squid wiki for details.
761 user= The users name (login)
763 password= The users password (for login= cache_peer option)
765 message= Message describing the reason for this response.
766 Available as %o in error pages.
767 Useful on (ERR and BH results).
769 tag= Apply a tag to a request. Only sets a tag once,
770 does not alter existing tags.
772 log= String to be logged in access.log. Available as
773 %ea in logformat specifications.
775 clt_conn_tag= Associates a TAG with the client TCP connection.
776 Please see url_rewrite_program related documentation for
779 Any keywords may be sent on any response whether OK, ERR or BH.
781 All response keyword values need to be a single token with URL
782 escaping, or enclosed in double quotes (") and escaped using \ on
783 any double quotes or \ characters within the value. The wrapping
784 double quotes are removed before the value is interpreted by Squid.
785 \r and \n are also replace by CR and LF.
787 Some example key values:
791 user="J. \"Bob\" Smith"
798 DEFAULT: ssl::certHasExpired ssl_error X509_V_ERR_CERT_HAS_EXPIRED
799 DEFAULT: ssl::certNotYetValid ssl_error X509_V_ERR_CERT_NOT_YET_VALID
800 DEFAULT: ssl::certDomainMismatch ssl_error SQUID_X509_V_ERR_DOMAIN_MISMATCH
801 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
802 DEFAULT: ssl::certSelfSigned ssl_error X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT
805 DEFAULT: manager url_regex -i ^cache_object:// +i ^https?://[^/]+/squid-internal-mgr/
806 DEFAULT: localhost src 127.0.0.1/32 ::1
807 DEFAULT: to_localhost dst 127.0.0.0/8 0.0.0.0/32 ::1
808 DEFAULT_DOC: ACLs all, manager, localhost, and to_localhost are predefined.
810 Defining an Access List
812 Every access list definition must begin with an aclname and acltype,
813 followed by either type-specific arguments or a quoted filename that
816 acl aclname acltype argument ...
817 acl aclname acltype "file" ...
819 When using "file", the file should contain one item per line.
821 Some acl types supports options which changes their default behaviour.
822 The available options are:
824 -i,+i By default, regular expressions are CASE-SENSITIVE. To make them
825 case-insensitive, use the -i option. To return case-sensitive
826 use the +i option between patterns, or make a new ACL line
829 -n Disable lookups and address type conversions. If lookup or
830 conversion is required because the parameter type (IP or
831 domain name) does not match the message address type (domain
832 name or IP), then the ACL would immediately declare a mismatch
833 without any warnings or lookups.
835 -- Used to stop processing all options, in the case the first acl
836 value has '-' character as first character (for example the '-'
837 is a valid domain name)
839 Some acl types require suspending the current request in order
840 to access some external data source.
841 Those which do are marked with the tag [slow], those which
842 don't are marked as [fast].
843 See http://wiki.squid-cache.org/SquidFaq/SquidAcl
844 for further information
846 ***** ACL TYPES AVAILABLE *****
848 acl aclname src ip-address/mask ... # clients IP address [fast]
849 acl aclname src addr1-addr2/mask ... # range of addresses [fast]
850 acl aclname dst [-n] ip-address/mask ... # URL host's IP address [slow]
851 acl aclname localip ip-address/mask ... # IP address the client connected to [fast]
853 acl aclname arp mac-address ... (xx:xx:xx:xx:xx:xx notation)
854 # The arp ACL requires the special configure option --enable-arp-acl.
855 # Furthermore, the ARP ACL code is not portable to all operating systems.
856 # It works on Linux, Solaris, Windows, FreeBSD, and some
857 # other *BSD variants.
860 # NOTE: Squid can only determine the MAC address for clients that are on
861 # the same subnet. If the client is on a different subnet,
862 # then Squid cannot find out its MAC address.
864 acl aclname srcdomain .foo.com ...
865 # reverse lookup, from client IP [slow]
866 acl aclname dstdomain [-n] .foo.com ...
867 # Destination server from URL [fast]
868 acl aclname srcdom_regex [-i] \.foo\.com ...
869 # regex matching client name [slow]
870 acl aclname dstdom_regex [-n] [-i] \.foo\.com ...
871 # regex matching server [fast]
873 # For dstdomain and dstdom_regex a reverse lookup is tried if a IP
874 # based URL is used and no match is found. The name "none" is used
875 # if the reverse lookup fails.
877 acl aclname src_as number ...
878 acl aclname dst_as number ...
880 # Except for access control, AS numbers can be used for
881 # routing of requests to specific caches. Here's an
882 # example for routing all requests for AS#1241 and only
883 # those to mycache.mydomain.net:
884 # acl asexample dst_as 1241
885 # cache_peer_access mycache.mydomain.net allow asexample
886 # cache_peer_access mycache_mydomain.net deny all
888 acl aclname peername myPeer ...
890 # match against a named cache_peer entry
891 # set unique name= on cache_peer lines for reliable use.
893 acl aclname time [day-abbrevs] [h1:m1-h2:m2]
903 # h1:m1 must be less than h2:m2
905 acl aclname url_regex [-i] ^http:// ...
906 # regex matching on whole URL [fast]
907 acl aclname urllogin [-i] [^a-zA-Z0-9] ...
908 # regex matching on URL login field
909 acl aclname urlpath_regex [-i] \.gif$ ...
910 # regex matching on URL path [fast]
912 acl aclname port 80 70 21 0-1024... # destination TCP port [fast]
914 acl aclname localport 3128 ... # TCP port the client connected to [fast]
915 # NP: for interception mode this is usually '80'
917 acl aclname myportname 3128 ... # http(s)_port name [fast]
919 acl aclname proto HTTP FTP ... # request protocol [fast]
921 acl aclname method GET POST ... # HTTP request method [fast]
923 acl aclname http_status 200 301 500- 400-403 ...
924 # status code in reply [fast]
926 acl aclname browser [-i] regexp ...
927 # pattern match on User-Agent header (see also req_header below) [fast]
929 acl aclname referer_regex [-i] regexp ...
930 # pattern match on Referer header [fast]
931 # Referer is highly unreliable, so use with care
933 acl aclname ident username ...
934 acl aclname ident_regex [-i] pattern ...
935 # string match on ident output [slow]
936 # use REQUIRED to accept any non-null ident.
938 acl aclname proxy_auth [-i] username ...
939 acl aclname proxy_auth_regex [-i] pattern ...
940 # perform http authentication challenge to the client and match against
941 # supplied credentials [slow]
943 # takes a list of allowed usernames.
944 # use REQUIRED to accept any valid username.
946 # Will use proxy authentication in forward-proxy scenarios, and plain
947 # http authenticaiton in reverse-proxy scenarios
949 # NOTE: when a Proxy-Authentication header is sent but it is not
950 # needed during ACL checking the username is NOT logged
953 # NOTE: proxy_auth requires a EXTERNAL authentication program
954 # to check username/password combinations (see
955 # auth_param directive).
957 # NOTE: proxy_auth can't be used in a transparent/intercepting proxy
958 # as the browser needs to be configured for using a proxy in order
959 # to respond to proxy authentication.
961 acl aclname snmp_community string ...
962 # A community string to limit access to your SNMP Agent [fast]
965 # acl snmppublic snmp_community public
967 acl aclname maxconn number
968 # This will be matched when the client's IP address has
969 # more than <number> TCP connections established. [fast]
970 # NOTE: This only measures direct TCP links so X-Forwarded-For
971 # indirect clients are not counted.
973 acl aclname max_user_ip [-s] number
974 # This will be matched when the user attempts to log in from more
975 # than <number> different ip addresses. The authenticate_ip_ttl
976 # parameter controls the timeout on the ip entries. [fast]
977 # If -s is specified the limit is strict, denying browsing
978 # from any further IP addresses until the ttl has expired. Without
979 # -s Squid will just annoy the user by "randomly" denying requests.
980 # (the counter is reset each time the limit is reached and a
982 # NOTE: in acceleration mode or where there is mesh of child proxies,
983 # clients may appear to come from multiple addresses if they are
984 # going through proxy farms, so a limit of 1 may cause user problems.
986 acl aclname random probability
987 # Pseudo-randomly match requests. Based on the probability given.
988 # Probability may be written as a decimal (0.333), fraction (1/3)
989 # or ratio of matches:non-matches (3:5).
991 acl aclname req_mime_type [-i] mime-type ...
992 # regex match against the mime type of the request generated
993 # by the client. Can be used to detect file upload or some
994 # types HTTP tunneling requests [fast]
995 # NOTE: This does NOT match the reply. You cannot use this
996 # to match the returned file type.
998 acl aclname req_header header-name [-i] any\.regex\.here
999 # regex match against any of the known request headers. May be
1000 # thought of as a superset of "browser", "referer" and "mime-type"
1003 acl aclname rep_mime_type [-i] mime-type ...
1004 # regex match against the mime type of the reply received by
1005 # squid. Can be used to detect file download or some
1006 # types HTTP tunneling requests. [fast]
1007 # NOTE: This has no effect in http_access rules. It only has
1008 # effect in rules that affect the reply data stream such as
1009 # http_reply_access.
1011 acl aclname rep_header header-name [-i] any\.regex\.here
1012 # regex match against any of the known reply headers. May be
1013 # thought of as a superset of "browser", "referer" and "mime-type"
1016 acl aclname external class_name [arguments...]
1017 # external ACL lookup via a helper class defined by the
1018 # external_acl_type directive [slow]
1020 acl aclname user_cert attribute values...
1021 # match against attributes in a user SSL certificate
1022 # attribute is one of DN/C/O/CN/L/ST [fast]
1024 acl aclname ca_cert attribute values...
1025 # match against attributes a users issuing CA SSL certificate
1026 # attribute is one of DN/C/O/CN/L/ST [fast]
1028 acl aclname ext_user username ...
1029 acl aclname ext_user_regex [-i] pattern ...
1030 # string match on username returned by external acl helper [slow]
1031 # use REQUIRED to accept any non-null user name.
1033 acl aclname tag tagvalue ...
1034 # string match on tag returned by external acl helper [fast]
1035 # DEPRECATED. Only the first tag will match with this ACL.
1036 # Use the 'note' ACL instead for handling multiple tag values.
1038 acl aclname hier_code codename ...
1039 # string match against squid hierarchy code(s); [fast]
1040 # e.g., DIRECT, PARENT_HIT, NONE, etc.
1042 # NOTE: This has no effect in http_access rules. It only has
1043 # effect in rules that affect the reply data stream such as
1044 # http_reply_access.
1046 acl aclname note name [value ...]
1047 # match transaction annotation [fast]
1048 # Without values, matches any annotation with a given name.
1049 # With value(s), matches any annotation with a given name that
1050 # also has one of the given values.
1051 # Names and values are compared using a string equality test.
1052 # Annotation sources include note and adaptation_meta directives
1053 # as well as helper and eCAP responses.
1055 acl aclname adaptation_service service ...
1056 # Matches the name of any icap_service, ecap_service,
1057 # adaptation_service_set, or adaptation_service_chain that Squid
1058 # has used (or attempted to use) for the master transaction.
1059 # This ACL must be defined after the corresponding adaptation
1060 # service is named in squid.conf. This ACL is usable with
1061 # adaptation_meta because it starts matching immediately after
1062 # the service has been selected for adaptation.
1065 acl aclname ssl_error errorname
1066 # match against SSL certificate validation error [fast]
1068 # For valid error names see in @DEFAULT_ERROR_DIR@/templates/error-details.txt
1071 # The following can be used as shortcuts for certificate properties:
1072 # [ssl::]certHasExpired: the "not after" field is in the past
1073 # [ssl::]certNotYetValid: the "not before" field is in the future
1074 # [ssl::]certUntrusted: The certificate issuer is not to be trusted.
1075 # [ssl::]certSelfSigned: The certificate is self signed.
1076 # [ssl::]certDomainMismatch: The certificate CN domain does not
1077 # match the name the name of the host we are connecting to.
1079 # The ssl::certHasExpired, ssl::certNotYetValid, ssl::certDomainMismatch,
1080 # ssl::certUntrusted, and ssl::certSelfSigned can also be used as
1081 # predefined ACLs, just like the 'all' ACL.
1083 # NOTE: The ssl_error ACL is only supported with sslproxy_cert_error,
1084 # sslproxy_cert_sign, and sslproxy_cert_adapt options.
1086 acl aclname server_cert_fingerprint [-sha1] fingerprint
1087 # match against server SSL certificate fingerprint [fast]
1089 # The fingerprint is the digest of the DER encoded version
1090 # of the whole certificate. The user should use the form: XX:XX:...
1091 # Optional argument specifies the digest algorithm to use.
1092 # The SHA1 digest algorithm is the default and is currently
1093 # the only algorithm supported (-sha1).
1095 acl aclname any-of acl1 acl2 ...
1096 # match any one of the acls [fast or slow]
1097 # The first matching ACL stops further ACL evaluation.
1099 # ACLs from multiple any-of lines with the same name are ORed.
1100 # For example, A = (a1 or a2) or (a3 or a4) can be written as
1101 # acl A any-of a1 a2
1102 # acl A any-of a3 a4
1104 # This group ACL is fast if all evaluated ACLs in the group are fast
1105 # and slow otherwise.
1107 acl aclname all-of acl1 acl2 ...
1108 # match all of the acls [fast or slow]
1109 # The first mismatching ACL stops further ACL evaluation.
1111 # ACLs from multiple all-of lines with the same name are ORed.
1112 # For example, B = (b1 and b2) or (b3 and b4) can be written as
1113 # acl B all-of b1 b2
1114 # acl B all-of b3 b4
1116 # This group ACL is fast if all evaluated ACLs in the group are fast
1117 # and slow otherwise.
1120 acl macaddress arp 09:00:2b:23:45:67
1121 acl myexample dst_as 1241
1122 acl password proxy_auth REQUIRED
1123 acl fileupload req_mime_type -i ^multipart/form-data$
1124 acl javascript rep_mime_type -i ^application/x-javascript$
1128 # Recommended minimum configuration:
1131 # Example rule allowing access from your local networks.
1132 # Adapt to list your (internal) IP networks from where browsing
1134 acl localnet src 10.0.0.0/8 # RFC1918 possible internal network
1135 acl localnet src 172.16.0.0/12 # RFC1918 possible internal network
1136 acl localnet src 192.168.0.0/16 # RFC1918 possible internal network
1137 acl localnet src fc00::/7 # RFC 4193 local private network range
1138 acl localnet src fe80::/10 # RFC 4291 link-local (directly plugged) machines
1140 acl SSL_ports port 443
1141 acl Safe_ports port 80 # http
1142 acl Safe_ports port 21 # ftp
1143 acl Safe_ports port 443 # https
1144 acl Safe_ports port 70 # gopher
1145 acl Safe_ports port 210 # wais
1146 acl Safe_ports port 1025-65535 # unregistered ports
1147 acl Safe_ports port 280 # http-mgmt
1148 acl Safe_ports port 488 # gss-http
1149 acl Safe_ports port 591 # filemaker
1150 acl Safe_ports port 777 # multiling http
1151 acl CONNECT method CONNECT
1155 NAME: follow_x_forwarded_for
1157 IFDEF: FOLLOW_X_FORWARDED_FOR
1158 LOC: Config.accessList.followXFF
1159 DEFAULT_IF_NONE: deny all
1160 DEFAULT_DOC: X-Forwarded-For header will be ignored.
1162 Allowing or Denying the X-Forwarded-For header to be followed to
1163 find the original source of a request.
1165 Requests may pass through a chain of several other proxies
1166 before reaching us. The X-Forwarded-For header will contain a
1167 comma-separated list of the IP addresses in the chain, with the
1168 rightmost address being the most recent.
1170 If a request reaches us from a source that is allowed by this
1171 configuration item, then we consult the X-Forwarded-For header
1172 to see where that host received the request from. If the
1173 X-Forwarded-For header contains multiple addresses, we continue
1174 backtracking until we reach an address for which we are not allowed
1175 to follow the X-Forwarded-For header, or until we reach the first
1176 address in the list. For the purpose of ACL used in the
1177 follow_x_forwarded_for directive the src ACL type always matches
1178 the address we are testing and srcdomain matches its rDNS.
1180 The end result of this process is an IP address that we will
1181 refer to as the indirect client address. This address may
1182 be treated as the client address for access control, ICAP, delay
1183 pools and logging, depending on the acl_uses_indirect_client,
1184 icap_uses_indirect_client, delay_pool_uses_indirect_client,
1185 log_uses_indirect_client and tproxy_uses_indirect_client options.
1187 This clause only supports fast acl types.
1188 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1190 SECURITY CONSIDERATIONS:
1192 Any host for which we follow the X-Forwarded-For header
1193 can place incorrect information in the header, and Squid
1194 will use the incorrect information as if it were the
1195 source address of the request. This may enable remote
1196 hosts to bypass any access control restrictions that are
1197 based on the client's source addresses.
1201 acl localhost src 127.0.0.1
1202 acl my_other_proxy srcdomain .proxy.example.com
1203 follow_x_forwarded_for allow localhost
1204 follow_x_forwarded_for allow my_other_proxy
1207 NAME: acl_uses_indirect_client
1210 IFDEF: FOLLOW_X_FORWARDED_FOR
1212 LOC: Config.onoff.acl_uses_indirect_client
1214 Controls whether the indirect client address
1215 (see follow_x_forwarded_for) is used instead of the
1216 direct client address in acl matching.
1218 NOTE: maxconn ACL considers direct TCP links and indirect
1219 clients will always have zero. So no match.
1222 NAME: delay_pool_uses_indirect_client
1225 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_DELAY_POOLS
1227 LOC: Config.onoff.delay_pool_uses_indirect_client
1229 Controls whether the indirect client address
1230 (see follow_x_forwarded_for) is used instead of the
1231 direct client address in delay pools.
1234 NAME: log_uses_indirect_client
1237 IFDEF: FOLLOW_X_FORWARDED_FOR
1239 LOC: Config.onoff.log_uses_indirect_client
1241 Controls whether the indirect client address
1242 (see follow_x_forwarded_for) is used instead of the
1243 direct client address in the access log.
1246 NAME: tproxy_uses_indirect_client
1249 IFDEF: FOLLOW_X_FORWARDED_FOR&&LINUX_NETFILTER
1251 LOC: Config.onoff.tproxy_uses_indirect_client
1253 Controls whether the indirect client address
1254 (see follow_x_forwarded_for) is used instead of the
1255 direct client address when spoofing the outgoing client.
1257 This has no effect on requests arriving in non-tproxy
1260 SECURITY WARNING: Usage of this option is dangerous
1261 and should not be used trivially. Correct configuration
1262 of follow_x_forewarded_for with a limited set of trusted
1263 sources is required to prevent abuse of your proxy.
1266 NAME: spoof_client_ip
1268 LOC: Config.accessList.spoof_client_ip
1270 DEFAULT_DOC: Allow spoofing on all TPROXY traffic.
1272 Control client IP address spoofing of TPROXY traffic based on
1273 defined access lists.
1275 spoof_client_ip allow|deny [!]aclname ...
1277 If there are no "spoof_client_ip" lines present, the default
1278 is to "allow" spoofing of any suitable request.
1280 Note that the cache_peer "no-tproxy" option overrides this ACL.
1282 This clause supports fast acl types.
1283 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1288 LOC: Config.accessList.http
1289 DEFAULT_IF_NONE: deny all
1290 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1292 Allowing or Denying access based on defined access lists
1294 Access to the HTTP port:
1295 http_access allow|deny [!]aclname ...
1297 NOTE on default values:
1299 If there are no "access" lines present, the default is to deny
1302 If none of the "access" lines cause a match, the default is the
1303 opposite of the last line in the list. If the last line was
1304 deny, the default is allow. Conversely, if the last line
1305 is allow, the default will be deny. For these reasons, it is a
1306 good idea to have an "deny all" entry at the end of your access
1307 lists to avoid potential confusion.
1309 This clause supports both fast and slow acl types.
1310 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1315 # Recommended minimum Access Permission configuration:
1317 # Deny requests to certain unsafe ports
1318 http_access deny !Safe_ports
1320 # Deny CONNECT to other than secure SSL ports
1321 http_access deny CONNECT !SSL_ports
1323 # Only allow cachemgr access from localhost
1324 http_access allow localhost manager
1325 http_access deny manager
1327 # We strongly recommend the following be uncommented to protect innocent
1328 # web applications running on the proxy server who think the only
1329 # one who can access services on "localhost" is a local user
1330 #http_access deny to_localhost
1333 # INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS
1336 # Example rule allowing access from your local networks.
1337 # Adapt localnet in the ACL section to list your (internal) IP networks
1338 # from where browsing should be allowed
1339 http_access allow localnet
1340 http_access allow localhost
1342 # And finally deny all other access to this proxy
1343 http_access deny all
1347 NAME: adapted_http_access http_access2
1349 LOC: Config.accessList.adapted_http
1351 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1353 Allowing or Denying access based on defined access lists
1355 Essentially identical to http_access, but runs after redirectors
1356 and ICAP/eCAP adaptation. Allowing access control based on their
1359 If not set then only http_access is used.
1362 NAME: http_reply_access
1364 LOC: Config.accessList.reply
1366 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1368 Allow replies to client requests. This is complementary to http_access.
1370 http_reply_access allow|deny [!] aclname ...
1372 NOTE: if there are no access lines present, the default is to allow
1375 If none of the access lines cause a match the opposite of the
1376 last line will apply. Thus it is good practice to end the rules
1377 with an "allow all" or "deny all" entry.
1379 This clause supports both fast and slow acl types.
1380 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1385 LOC: Config.accessList.icp
1387 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1389 Allowing or Denying access to the ICP port based on defined
1392 icp_access allow|deny [!]aclname ...
1394 NOTE: The default if no icp_access lines are present is to
1395 deny all traffic. This default may cause problems with peers
1398 This clause only supports fast acl types.
1399 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1401 # Allow ICP queries from local networks only
1402 #icp_access allow localnet
1403 #icp_access deny all
1409 LOC: Config.accessList.htcp
1411 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1413 Allowing or Denying access to the HTCP port based on defined
1416 htcp_access allow|deny [!]aclname ...
1418 See also htcp_clr_access for details on access control for
1419 cache purge (CLR) HTCP messages.
1421 NOTE: The default if no htcp_access lines are present is to
1422 deny all traffic. This default may cause problems with peers
1423 using the htcp option.
1425 This clause only supports fast acl types.
1426 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1428 # Allow HTCP queries from local networks only
1429 #htcp_access allow localnet
1430 #htcp_access deny all
1433 NAME: htcp_clr_access
1436 LOC: Config.accessList.htcp_clr
1438 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1440 Allowing or Denying access to purge content using HTCP based
1441 on defined access lists.
1442 See htcp_access for details on general HTCP access control.
1444 htcp_clr_access allow|deny [!]aclname ...
1446 This clause only supports fast acl types.
1447 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1449 # Allow HTCP CLR requests from trusted peers
1450 acl htcp_clr_peer src 192.0.2.2 2001:DB8::2
1451 htcp_clr_access allow htcp_clr_peer
1452 htcp_clr_access deny all
1457 LOC: Config.accessList.miss
1459 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1461 Determins whether network access is permitted when satisfying a request.
1464 to force your neighbors to use you as a sibling instead of
1467 acl localclients src 192.0.2.0/24 2001:DB8::a:0/64
1468 miss_access deny !localclients
1469 miss_access allow all
1471 This means only your local clients are allowed to fetch relayed/MISS
1472 replies from the network and all other clients can only fetch cached
1475 The default for this setting allows all clients who passed the
1476 http_access rules to relay via this proxy.
1478 This clause only supports fast acl types.
1479 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1482 NAME: ident_lookup_access
1486 DEFAULT_DOC: Unless rules exist in squid.conf, IDENT is not fetched.
1487 LOC: Ident::TheConfig.identLookup
1489 A list of ACL elements which, if matched, cause an ident
1490 (RFC 931) lookup to be performed for this request. For
1491 example, you might choose to always perform ident lookups
1492 for your main multi-user Unix boxes, but not for your Macs
1493 and PCs. By default, ident lookups are not performed for
1496 To enable ident lookups for specific client addresses, you
1497 can follow this example:
1499 acl ident_aware_hosts src 198.168.1.0/24
1500 ident_lookup_access allow ident_aware_hosts
1501 ident_lookup_access deny all
1503 Only src type ACL checks are fully supported. A srcdomain
1504 ACL might work at times, but it will not always provide
1507 This clause only supports fast acl types.
1508 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1511 NAME: reply_body_max_size
1512 COMMENT: size [acl acl...]
1515 DEFAULT_DOC: No limit is applied.
1516 LOC: Config.ReplyBodySize
1518 This option specifies the maximum size of a reply body. It can be
1519 used to prevent users from downloading very large files, such as
1520 MP3's and movies. When the reply headers are received, the
1521 reply_body_max_size lines are processed, and the first line where
1522 all (if any) listed ACLs are true is used as the maximum body size
1525 This size is checked twice. First when we get the reply headers,
1526 we check the content-length value. If the content length value exists
1527 and is larger than the allowed size, the request is denied and the
1528 user receives an error message that says "the request or reply
1529 is too large." If there is no content-length, and the reply
1530 size exceeds this limit, the client's connection is just closed
1531 and they will receive a partial reply.
1533 WARNING: downstream caches probably can not detect a partial reply
1534 if there is no content-length header, so they will cache
1535 partial responses and give them out as hits. You should NOT
1536 use this option if you have downstream caches.
1538 WARNING: A maximum size smaller than the size of squid's error messages
1539 will cause an infinite loop and crash squid. Ensure that the smallest
1540 non-zero value you use is greater that the maximum header size plus
1541 the size of your largest error page.
1543 If you set this parameter none (the default), there will be
1546 Configuration Format is:
1547 reply_body_max_size SIZE UNITS [acl ...]
1549 reply_body_max_size 10 MB
1555 -----------------------------------------------------------------------------
1558 NAME: http_port ascii_port
1563 Usage: port [mode] [options]
1564 hostname:port [mode] [options]
1565 1.2.3.4:port [mode] [options]
1567 The socket addresses where Squid will listen for HTTP client
1568 requests. You may specify multiple socket addresses.
1569 There are three forms: port alone, hostname with port, and
1570 IP address with port. If you specify a hostname or IP
1571 address, Squid binds the socket to that specific
1572 address. Most likely, you do not need to bind to a specific
1573 address, so you can use the port number alone.
1575 If you are running Squid in accelerator mode, you
1576 probably want to listen on port 80 also, or instead.
1578 The -a command line option may be used to specify additional
1579 port(s) where Squid listens for proxy request. Such ports will
1580 be plain proxy ports with no options.
1582 You may specify multiple socket addresses on multiple lines.
1586 intercept Support for IP-Layer interception of
1587 outgoing requests without browser settings.
1588 NP: disables authentication and IPv6 on the port.
1590 tproxy Support Linux TPROXY for spoofing outgoing
1591 connections using the client IP address.
1592 NP: disables authentication and maybe IPv6 on the port.
1594 accel Accelerator / reverse proxy mode
1596 ssl-bump For each CONNECT request allowed by ssl_bump ACLs,
1597 establish secure connection with the client and with
1598 the server, decrypt HTTPS messages as they pass through
1599 Squid, and treat them as unencrypted HTTP messages,
1600 becoming the man-in-the-middle.
1602 The ssl_bump option is required to fully enable
1603 bumping of CONNECT requests.
1605 Omitting the mode flag causes default forward proxy mode to be used.
1608 Accelerator Mode Options:
1610 defaultsite=domainname
1611 What to use for the Host: header if it is not present
1612 in a request. Determines what site (not origin server)
1613 accelerators should consider the default.
1615 no-vhost Disable using HTTP/1.1 Host header for virtual domain support.
1617 protocol= Protocol to reconstruct accelerated and intercepted
1618 requests with. Defaults to HTTP/1.1 for http_port and
1619 HTTPS/1.1 for https_port.
1620 When an unsupported value is configured Squid will
1621 produce a FATAL error.
1622 Values: HTTP or HTTP/1.1, HTTPS or HTTPS/1.1
1624 vport Virtual host port support. Using the http_port number
1625 instead of the port passed on Host: headers.
1627 vport=NN Virtual host port support. Using the specified port
1628 number instead of the port passed on Host: headers.
1631 Act as if this Squid is the origin server.
1632 This currently means generate new Date: and Expires:
1633 headers on HIT instead of adding Age:.
1635 ignore-cc Ignore request Cache-Control headers.
1637 WARNING: This option violates HTTP specifications if
1638 used in non-accelerator setups.
1640 allow-direct Allow direct forwarding in accelerator mode. Normally
1641 accelerated requests are denied direct forwarding as if
1642 never_direct was used.
1644 WARNING: this option opens accelerator mode to security
1645 vulnerabilities usually only affecting in interception
1646 mode. Make sure to protect forwarding with suitable
1647 http_access rules when using this.
1650 SSL Bump Mode Options:
1651 In addition to these options ssl-bump requires TLS/SSL options.
1653 generate-host-certificates[=<on|off>]
1654 Dynamically create SSL server certificates for the
1655 destination hosts of bumped CONNECT requests.When
1656 enabled, the cert and key options are used to sign
1657 generated certificates. Otherwise generated
1658 certificate will be selfsigned.
1659 If there is a CA certificate lifetime of the generated
1660 certificate equals lifetime of the CA certificate. If
1661 generated certificate is selfsigned lifetime is three
1663 This option is enabled by default when ssl-bump is used.
1664 See the ssl-bump option above for more information.
1666 dynamic_cert_mem_cache_size=SIZE
1667 Approximate total RAM size spent on cached generated
1668 certificates. If set to zero, caching is disabled. The
1669 default value is 4MB.
1673 cert= Path to SSL certificate (PEM format).
1675 key= Path to SSL private key file (PEM format)
1676 if not specified, the certificate file is
1677 assumed to be a combined certificate and
1680 version= The version of SSL/TLS supported
1681 1 automatic (default)
1688 cipher= Colon separated list of supported ciphers.
1689 NOTE: some ciphers such as EDH ciphers depend on
1690 additional settings. If those settings are
1691 omitted the ciphers may be silently ignored
1692 by the OpenSSL library.
1694 options= Various SSL implementation options. The most important
1696 NO_SSLv2 Disallow the use of SSLv2
1697 NO_SSLv3 Disallow the use of SSLv3
1698 NO_TLSv1 Disallow the use of TLSv1.0
1699 NO_TLSv1_1 Disallow the use of TLSv1.1
1700 NO_TLSv1_2 Disallow the use of TLSv1.2
1701 SINGLE_DH_USE Always create a new key when using
1702 temporary/ephemeral DH key exchanges
1703 ALL Enable various bug workarounds
1704 suggested as "harmless" by OpenSSL
1705 Be warned that this reduces SSL/TLS
1706 strength to some attacks.
1707 See OpenSSL SSL_CTX_set_options documentation for a
1708 complete list of options.
1710 clientca= File containing the list of CAs to use when
1711 requesting a client certificate.
1713 cafile= File containing additional CA certificates to
1714 use when verifying client certificates. If unset
1715 clientca will be used.
1717 capath= Directory containing additional CA certificates
1718 and CRL lists to use when verifying client certificates.
1720 crlfile= File of additional CRL lists to use when verifying
1721 the client certificate, in addition to CRLs stored in
1722 the capath. Implies VERIFY_CRL flag below.
1724 dhparams= File containing DH parameters for temporary/ephemeral
1725 DH key exchanges. See OpenSSL documentation for details
1726 on how to create this file.
1727 WARNING: EDH ciphers will be silently disabled if this
1730 sslflags= Various flags modifying the use of SSL:
1732 Don't request client certificates
1733 immediately, but wait until acl processing
1734 requires a certificate (not yet implemented).
1736 Don't use the default CA lists built in
1739 Don't allow for session reuse. Each connection
1740 will result in a new SSL session.
1742 Verify CRL lists when accepting client
1745 Verify CRL lists for all certificates in the
1746 client certificate chain.
1748 sslcontext= SSL session ID context identifier.
1752 connection-auth[=on|off]
1753 use connection-auth=off to tell Squid to prevent
1754 forwarding Microsoft connection oriented authentication
1755 (NTLM, Negotiate and Kerberos)
1757 disable-pmtu-discovery=
1758 Control Path-MTU discovery usage:
1759 off lets OS decide on what to do (default).
1760 transparent disable PMTU discovery when transparent
1762 always disable always PMTU discovery.
1764 In many setups of transparently intercepting proxies
1765 Path-MTU discovery can not work on traffic towards the
1766 clients. This is the case when the intercepting device
1767 does not fully track connections and fails to forward
1768 ICMP must fragment messages to the cache server. If you
1769 have such setup and experience that certain clients
1770 sporadically hang or never complete requests set
1771 disable-pmtu-discovery option to 'transparent'.
1773 name= Specifies a internal name for the port. Defaults to
1774 the port specification (port or addr:port)
1776 tcpkeepalive[=idle,interval,timeout]
1777 Enable TCP keepalive probes of idle connections.
1778 In seconds; idle is the initial time before TCP starts
1779 probing the connection, interval how often to probe, and
1780 timeout the time before giving up.
1782 If you run Squid on a dual-homed machine with an internal
1783 and an external interface we recommend you to specify the
1784 internal address:port in http_port. This way Squid will only be
1785 visible on the internal address.
1789 # Squid normally listens to port 3128
1790 http_port @DEFAULT_HTTP_PORT@
1800 Usage: [ip:]port cert=certificate.pem [key=key.pem] [mode] [options...]
1802 The socket address where Squid will listen for client requests made
1803 over TLS or SSL connections. Commonly referred to as HTTPS.
1805 This is most useful for situations where you are running squid in
1806 accelerator mode and you want to do the SSL work at the accelerator level.
1808 You may specify multiple socket addresses on multiple lines,
1809 each with their own SSL certificate and/or options.
1813 accel Accelerator / reverse proxy mode
1815 intercept Support for IP-Layer interception of
1816 outgoing requests without browser settings.
1817 NP: disables authentication and IPv6 on the port.
1819 tproxy Support Linux TPROXY for spoofing outgoing
1820 connections using the client IP address.
1821 NP: disables authentication and maybe IPv6 on the port.
1823 ssl-bump For each intercepted connection allowed by ssl_bump
1824 ACLs, establish a secure connection with the client and with
1825 the server, decrypt HTTPS messages as they pass through
1826 Squid, and treat them as unencrypted HTTP messages,
1827 becoming the man-in-the-middle.
1829 An "ssl_bump server-first" match is required to
1830 fully enable bumping of intercepted SSL connections.
1832 Requires tproxy or intercept.
1834 Omitting the mode flag causes default forward proxy mode to be used.
1837 See http_port for a list of generic options
1842 cert= Path to SSL certificate (PEM format).
1844 key= Path to SSL private key file (PEM format)
1845 if not specified, the certificate file is
1846 assumed to be a combined certificate and
1849 version= The version of SSL/TLS supported
1850 1 automatic (default)
1855 cipher= Colon separated list of supported ciphers.
1857 options= Various SSL engine options. The most important
1859 NO_SSLv2 Disallow the use of SSLv2
1860 NO_SSLv3 Disallow the use of SSLv3
1861 NO_TLSv1 Disallow the use of TLSv1
1862 SINGLE_DH_USE Always create a new key when using
1863 temporary/ephemeral DH key exchanges
1864 See src/ssl_support.c or OpenSSL SSL_CTX_set_options
1865 documentation for a complete list of options.
1867 clientca= File containing the list of CAs to use when
1868 requesting a client certificate.
1870 cafile= File containing additional CA certificates to
1871 use when verifying client certificates. If unset
1872 clientca will be used.
1874 capath= Directory containing additional CA certificates
1875 and CRL lists to use when verifying client certificates.
1877 crlfile= File of additional CRL lists to use when verifying
1878 the client certificate, in addition to CRLs stored in
1879 the capath. Implies VERIFY_CRL flag below.
1881 dhparams= File containing DH parameters for temporary/ephemeral
1884 sslflags= Various flags modifying the use of SSL:
1886 Don't request client certificates
1887 immediately, but wait until acl processing
1888 requires a certificate (not yet implemented).
1890 Don't use the default CA lists built in
1893 Don't allow for session reuse. Each connection
1894 will result in a new SSL session.
1896 Verify CRL lists when accepting client
1899 Verify CRL lists for all certificates in the
1900 client certificate chain.
1902 sslcontext= SSL session ID context identifier.
1904 generate-host-certificates[=<on|off>]
1905 Dynamically create SSL server certificates for the
1906 destination hosts of bumped SSL requests.When
1907 enabled, the cert and key options are used to sign
1908 generated certificates. Otherwise generated
1909 certificate will be selfsigned.
1910 If there is CA certificate life time of generated
1911 certificate equals lifetime of CA certificate. If
1912 generated certificate is selfsigned lifetime is three
1914 This option is enabled by default when SslBump is used.
1915 See the sslBump option above for more information.
1917 dynamic_cert_mem_cache_size=SIZE
1918 Approximate total RAM size spent on cached generated
1919 certificates. If set to zero, caching is disabled. The
1920 default value is 4MB.
1922 See http_port for a list of available options.
1925 NAME: tcp_outgoing_tos tcp_outgoing_ds tcp_outgoing_dscp
1928 LOC: Ip::Qos::TheConfig.tosToServer
1930 Allows you to select a TOS/Diffserv value for packets outgoing
1931 on the server side, based on an ACL.
1933 tcp_outgoing_tos ds-field [!]aclname ...
1935 Example where normal_service_net uses the TOS value 0x00
1936 and good_service_net uses 0x20
1938 acl normal_service_net src 10.0.0.0/24
1939 acl good_service_net src 10.0.1.0/24
1940 tcp_outgoing_tos 0x00 normal_service_net
1941 tcp_outgoing_tos 0x20 good_service_net
1943 TOS/DSCP values really only have local significance - so you should
1944 know what you're specifying. For more information, see RFC2474,
1945 RFC2475, and RFC3260.
1947 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
1948 "default" to use whatever default your host has. Note that in
1949 practice often only multiples of 4 is usable as the two rightmost bits
1950 have been redefined for use by ECN (RFC 3168 section 23.1).
1952 Processing proceeds in the order specified, and stops at first fully
1955 Only fast ACLs are supported.
1958 NAME: clientside_tos
1961 LOC: Ip::Qos::TheConfig.tosToClient
1963 Allows you to select a TOS/Diffserv value for packets being transmitted
1964 on the client-side, based on an ACL.
1966 clientside_tos ds-field [!]aclname ...
1968 Example where normal_service_net uses the TOS value 0x00
1969 and good_service_net uses 0x20
1971 acl normal_service_net src 10.0.0.0/24
1972 acl good_service_net src 10.0.1.0/24
1973 clientside_tos 0x00 normal_service_net
1974 clientside_tos 0x20 good_service_net
1976 Note: This feature is incompatible with qos_flows. Any TOS values set here
1977 will be overwritten by TOS values in qos_flows.
1980 NAME: tcp_outgoing_mark
1982 IFDEF: SO_MARK&&USE_LIBCAP
1984 LOC: Ip::Qos::TheConfig.nfmarkToServer
1986 Allows you to apply a Netfilter mark value to outgoing packets
1987 on the server side, based on an ACL.
1989 tcp_outgoing_mark mark-value [!]aclname ...
1991 Example where normal_service_net uses the mark value 0x00
1992 and good_service_net uses 0x20
1994 acl normal_service_net src 10.0.0.0/24
1995 acl good_service_net src 10.0.1.0/24
1996 tcp_outgoing_mark 0x00 normal_service_net
1997 tcp_outgoing_mark 0x20 good_service_net
1999 Only fast ACLs are supported.
2002 NAME: clientside_mark
2004 IFDEF: SO_MARK&&USE_LIBCAP
2006 LOC: Ip::Qos::TheConfig.nfmarkToClient
2008 Allows you to apply a Netfilter mark value to packets being transmitted
2009 on the client-side, based on an ACL.
2011 clientside_mark mark-value [!]aclname ...
2013 Example where normal_service_net uses the mark value 0x00
2014 and good_service_net uses 0x20
2016 acl normal_service_net src 10.0.0.0/24
2017 acl good_service_net src 10.0.1.0/24
2018 clientside_mark 0x00 normal_service_net
2019 clientside_mark 0x20 good_service_net
2021 Note: This feature is incompatible with qos_flows. Any mark values set here
2022 will be overwritten by mark values in qos_flows.
2029 LOC: Ip::Qos::TheConfig
2031 Allows you to select a TOS/DSCP value to mark outgoing
2032 connections to the client, based on where the reply was sourced.
2033 For platforms using netfilter, allows you to set a netfilter mark
2034 value instead of, or in addition to, a TOS value.
2036 By default this functionality is disabled. To enable it with the default
2037 settings simply use "qos_flows mark" or "qos_flows tos". Default
2038 settings will result in the netfilter mark or TOS value being copied
2039 from the upstream connection to the client. Note that it is the connection
2040 CONNMARK value not the packet MARK value that is copied.
2042 It is not currently possible to copy the mark or TOS value from the
2043 client to the upstream connection request.
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
2360 NAME: sslproxy_session_ttl
2363 LOC: Config.SSL.session_ttl
2366 Sets the timeout value for SSL sessions
2369 NAME: sslproxy_session_cache_size
2372 LOC: Config.SSL.sessionCacheSize
2375 Sets the cache size to use for ssl session
2380 TYPE: sslproxy_ssl_bump
2381 LOC: Config.accessList.ssl_bump
2382 DEFAULT_DOC: Does not bump unless rules are present in squid.conf
2385 This option is consulted when a CONNECT request is received on
2386 an http_port (or a new connection is intercepted at an
2387 https_port), provided that port was configured with an ssl-bump
2388 flag. The subsequent data on the connection is either treated as
2389 HTTPS and decrypted OR tunneled at TCP level without decryption,
2390 depending on the first bumping "mode" which ACLs match.
2392 ssl_bump <mode> [!]acl ...
2394 The following bumping modes are supported:
2397 Allow bumping of the connection. Establish a secure connection
2398 with the client first, then connect to the server. This old mode
2399 does not allow Squid to mimic server SSL certificate and does
2400 not work with intercepted SSL connections.
2403 Allow bumping of the connection. Establish a secure connection
2404 with the server first, then establish a secure connection with
2405 the client, using a mimicked server certificate. Works with both
2406 CONNECT requests and intercepted SSL connections.
2409 Become a TCP tunnel without decoding the connection.
2410 Works with both CONNECT requests and intercepted SSL
2411 connections. This is the default behavior when no
2412 ssl_bump option is given or no ssl_bump ACLs match.
2414 By default, no connections are bumped.
2416 The first matching ssl_bump option wins. If no ACLs match, the
2417 connection is not bumped. Unlike most allow/deny ACL lists, ssl_bump
2418 does not have an implicit "negate the last given option" rule. You
2419 must make that rule explicit if you convert old ssl_bump allow/deny
2420 rules that rely on such an implicit rule.
2422 This clause supports both fast and slow acl types.
2423 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2425 See also: http_port ssl-bump, https_port ssl-bump
2428 # Example: Bump all requests except those originating from
2429 # localhost or those going to example.com.
2431 acl broken_sites dstdomain .example.com
2432 ssl_bump none localhost
2433 ssl_bump none broken_sites
2434 ssl_bump server-first all
2437 NAME: sslproxy_flags
2440 LOC: Config.ssl_client.flags
2443 Various flags modifying the use of SSL while proxying https:// URLs:
2444 DONT_VERIFY_PEER Accept certificates that fail verification.
2445 For refined control, see sslproxy_cert_error.
2446 NO_DEFAULT_CA Don't use the default CA list built in
2450 NAME: sslproxy_cert_error
2453 DEFAULT_DOC: Server certificate errors terminate the transaction.
2454 LOC: Config.ssl_client.cert_error
2457 Use this ACL to bypass server certificate validation errors.
2459 For example, the following lines will bypass all validation errors
2460 when talking to servers for example.com. All other
2461 validation errors will result in ERR_SECURE_CONNECT_FAIL error.
2463 acl BrokenButTrustedServers dstdomain example.com
2464 sslproxy_cert_error allow BrokenButTrustedServers
2465 sslproxy_cert_error deny all
2467 This clause only supports fast acl types.
2468 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2469 Using slow acl types may result in server crashes
2471 Without this option, all server certificate validation errors
2472 terminate the transaction to protect Squid and the client.
2474 SQUID_X509_V_ERR_INFINITE_VALIDATION error cannot be bypassed
2475 but should not happen unless your OpenSSL library is buggy.
2478 Bypassing validation errors is dangerous because an
2479 error usually implies that the server cannot be trusted
2480 and the connection may be insecure.
2482 See also: sslproxy_flags and DONT_VERIFY_PEER.
2485 NAME: sslproxy_cert_sign
2488 POSTSCRIPTUM: signUntrusted ssl::certUntrusted
2489 POSTSCRIPTUM: signSelf ssl::certSelfSigned
2490 POSTSCRIPTUM: signTrusted all
2491 TYPE: sslproxy_cert_sign
2492 LOC: Config.ssl_client.cert_sign
2495 sslproxy_cert_sign <signing algorithm> acl ...
2497 The following certificate signing algorithms are supported:
2500 Sign using the configured CA certificate which is usually
2501 placed in and trusted by end-user browsers. This is the
2502 default for trusted origin server certificates.
2505 Sign to guarantee an X509_V_ERR_CERT_UNTRUSTED browser error.
2506 This is the default for untrusted origin server certificates
2507 that are not self-signed (see ssl::certUntrusted).
2510 Sign using a self-signed certificate with the right CN to
2511 generate a X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT error in the
2512 browser. This is the default for self-signed origin server
2513 certificates (see ssl::certSelfSigned).
2515 This clause only supports fast acl types.
2517 When sslproxy_cert_sign acl(s) match, Squid uses the corresponding
2518 signing algorithm to generate the certificate and ignores all
2519 subsequent sslproxy_cert_sign options (the first match wins). If no
2520 acl(s) match, the default signing algorithm is determined by errors
2521 detected when obtaining and validating the origin server certificate.
2523 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2524 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2525 CONNECT request that carries a domain name. In all other cases (CONNECT
2526 to an IP address or an intercepted SSL connection), Squid cannot detect
2527 the domain mismatch at certificate generation time when
2528 bump-server-first is used.
2531 NAME: sslproxy_cert_adapt
2534 TYPE: sslproxy_cert_adapt
2535 LOC: Config.ssl_client.cert_adapt
2538 sslproxy_cert_adapt <adaptation algorithm> acl ...
2540 The following certificate adaptation algorithms are supported:
2543 Sets the "Not After" property to the "Not After" property of
2544 the CA certificate used to sign generated certificates.
2547 Sets the "Not Before" property to the "Not Before" property of
2548 the CA certificate used to sign generated certificates.
2550 setCommonName or setCommonName{CN}
2551 Sets Subject.CN property to the host name specified as a
2552 CN parameter or, if no explicit CN parameter was specified,
2553 extracted from the CONNECT request. It is a misconfiguration
2554 to use setCommonName without an explicit parameter for
2555 intercepted or tproxied SSL connections.
2557 This clause only supports fast acl types.
2559 Squid first groups sslproxy_cert_adapt options by adaptation algorithm.
2560 Within a group, when sslproxy_cert_adapt acl(s) match, Squid uses the
2561 corresponding adaptation algorithm to generate the certificate and
2562 ignores all subsequent sslproxy_cert_adapt options in that algorithm's
2563 group (i.e., the first match wins within each algorithm group). If no
2564 acl(s) match, the default mimicking action takes place.
2566 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2567 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2568 CONNECT request that carries a domain name. In all other cases (CONNECT
2569 to an IP address or an intercepted SSL connection), Squid cannot detect
2570 the domain mismatch at certificate generation time when
2571 bump-server-first is used.
2574 NAME: sslpassword_program
2577 LOC: Config.Program.ssl_password
2580 Specify a program used for entering SSL key passphrases
2581 when using encrypted SSL certificate keys. If not specified
2582 keys must either be unencrypted, or Squid started with the -N
2583 option to allow it to query interactively for the passphrase.
2585 The key file name is given as argument to the program allowing
2586 selection of the right password if you have multiple encrypted
2591 OPTIONS RELATING TO EXTERNAL SSL_CRTD
2592 -----------------------------------------------------------------------------
2595 NAME: sslcrtd_program
2598 DEFAULT: @DEFAULT_SSL_CRTD@ -s @DEFAULT_SSL_DB_DIR@ -M 4MB
2599 LOC: Ssl::TheConfig.ssl_crtd
2601 Specify the location and options of the executable for ssl_crtd process.
2602 @DEFAULT_SSL_CRTD@ program requires -s and -M parameters
2603 For more information use:
2604 @DEFAULT_SSL_CRTD@ -h
2607 NAME: sslcrtd_children
2608 TYPE: HelperChildConfig
2610 DEFAULT: 32 startup=5 idle=1
2611 LOC: Ssl::TheConfig.ssl_crtdChildren
2613 The maximum number of processes spawn to service ssl server.
2614 The maximum this may be safely set to is 32.
2616 The startup= and idle= options allow some measure of skew in your
2621 Sets the minimum number of processes to spawn when Squid
2622 starts or reconfigures. When set to zero the first request will
2623 cause spawning of the first child process to handle it.
2625 Starting too few children temporary slows Squid under load while it
2626 tries to spawn enough additional processes to cope with traffic.
2630 Sets a minimum of how many processes Squid is to try and keep available
2631 at all times. When traffic begins to rise above what the existing
2632 processes can handle this many more will be spawned up to the maximum
2633 configured. A minimum setting of 1 is required.
2635 You must have at least one ssl_crtd process.
2638 NAME: sslcrtvalidator_program
2642 LOC: Ssl::TheConfig.ssl_crt_validator
2644 Specify the location and options of the executable for ssl_crt_validator
2647 Usage: sslcrtvalidator_program [ttl=n] [cache=n] path ...
2650 ttl=n TTL in seconds for cached results. The default is 60 secs
2651 cache=n limit the result cache size. The default value is 2048
2654 NAME: sslcrtvalidator_children
2655 TYPE: HelperChildConfig
2657 DEFAULT: 32 startup=5 idle=1 concurrency=1
2658 LOC: Ssl::TheConfig.ssl_crt_validator_Children
2660 The maximum number of processes spawn to service SSL server.
2661 The maximum this may be safely set to is 32.
2663 The startup= and idle= options allow some measure of skew in your
2668 Sets the minimum number of processes to spawn when Squid
2669 starts or reconfigures. When set to zero the first request will
2670 cause spawning of the first child process to handle it.
2672 Starting too few children temporary slows Squid under load while it
2673 tries to spawn enough additional processes to cope with traffic.
2677 Sets a minimum of how many processes Squid is to try and keep available
2678 at all times. When traffic begins to rise above what the existing
2679 processes can handle this many more will be spawned up to the maximum
2680 configured. A minimum setting of 1 is required.
2684 The number of requests each certificate validator helper can handle in
2685 parallel. A value of 0 indicates the certficate validator does not
2686 support concurrency. Defaults to 1.
2688 When this directive is set to a value >= 1 then the protocol
2689 used to communicate with the helper is modified to include
2690 a request ID in front of the request/response. The request
2691 ID from the request must be echoed back with the response
2694 You must have at least one ssl_crt_validator process.
2698 OPTIONS WHICH AFFECT THE NEIGHBOR SELECTION ALGORITHM
2699 -----------------------------------------------------------------------------
2707 To specify other caches in a hierarchy, use the format:
2709 cache_peer hostname type http-port icp-port [options]
2714 # hostname type port port options
2715 # -------------------- -------- ----- ----- -----------
2716 cache_peer parent.foo.net parent 3128 3130 default
2717 cache_peer sib1.foo.net sibling 3128 3130 proxy-only
2718 cache_peer sib2.foo.net sibling 3128 3130 proxy-only
2719 cache_peer example.com parent 80 0 default
2720 cache_peer cdn.example.com sibling 3128 0
2722 type: either 'parent', 'sibling', or 'multicast'.
2724 proxy-port: The port number where the peer accept HTTP requests.
2725 For other Squid proxies this is usually 3128
2726 For web servers this is usually 80
2728 icp-port: Used for querying neighbor caches about objects.
2729 Set to 0 if the peer does not support ICP or HTCP.
2730 See ICP and HTCP options below for additional details.
2733 ==== ICP OPTIONS ====
2735 You MUST also set icp_port and icp_access explicitly when using these options.
2736 The defaults will prevent peer traffic using ICP.
2739 no-query Disable ICP queries to this neighbor.
2742 Indicates the named peer is a member of a multicast group.
2743 ICP queries will not be sent directly to the peer, but ICP
2744 replies will be accepted from it.
2746 closest-only Indicates that, for ICP_OP_MISS replies, we'll only forward
2747 CLOSEST_PARENT_MISSes and never FIRST_PARENT_MISSes.
2750 To only send ICP queries to this neighbor infrequently.
2751 This is used to keep the neighbor round trip time updated
2752 and is usually used in conjunction with weighted-round-robin.
2755 ==== HTCP OPTIONS ====
2757 You MUST also set htcp_port and htcp_access explicitly when using these options.
2758 The defaults will prevent peer traffic using HTCP.
2761 htcp Send HTCP, instead of ICP, queries to the neighbor.
2762 You probably also want to set the "icp-port" to 4827
2763 instead of 3130. This directive accepts a comma separated
2764 list of options described below.
2766 htcp=oldsquid Send HTCP to old Squid versions (2.5 or earlier).
2768 htcp=no-clr Send HTCP to the neighbor but without
2769 sending any CLR requests. This cannot be used with
2772 htcp=only-clr Send HTCP to the neighbor but ONLY CLR requests.
2773 This cannot be used with no-clr.
2776 Send HTCP to the neighbor including CLRs but only when
2777 they do not result from PURGE requests.
2780 Forward any HTCP CLR requests this proxy receives to the peer.
2783 ==== PEER SELECTION METHODS ====
2785 The default peer selection method is ICP, with the first responding peer
2786 being used as source. These options can be used for better load balancing.
2789 default This is a parent cache which can be used as a "last-resort"
2790 if a peer cannot be located by any of the peer-selection methods.
2791 If specified more than once, only the first is used.
2793 round-robin Load-Balance parents which should be used in a round-robin
2794 fashion in the absence of any ICP queries.
2795 weight=N can be used to add bias.
2797 weighted-round-robin
2798 Load-Balance parents which should be used in a round-robin
2799 fashion with the frequency of each parent being based on the
2800 round trip time. Closer parents are used more often.
2801 Usually used for background-ping parents.
2802 weight=N can be used to add bias.
2804 carp Load-Balance parents which should be used as a CARP array.
2805 The requests will be distributed among the parents based on the
2806 CARP load balancing hash function based on their weight.
2808 userhash Load-balance parents based on the client proxy_auth or ident username.
2810 sourcehash Load-balance parents based on the client source IP.
2813 To be used only for cache peers of type "multicast".
2814 ALL members of this multicast group have "sibling"
2815 relationship with it, not "parent". This is to a multicast
2816 group when the requested object would be fetched only from
2817 a "parent" cache, anyway. It's useful, e.g., when
2818 configuring a pool of redundant Squid proxies, being
2819 members of the same multicast group.
2822 ==== PEER SELECTION OPTIONS ====
2824 weight=N use to affect the selection of a peer during any weighted
2825 peer-selection mechanisms.
2826 The weight must be an integer; default is 1,
2827 larger weights are favored more.
2828 This option does not affect parent selection if a peering
2829 protocol is not in use.
2831 basetime=N Specify a base amount to be subtracted from round trip
2833 It is subtracted before division by weight in calculating
2834 which parent to fectch from. If the rtt is less than the
2835 base time the rtt is set to a minimal value.
2837 ttl=N Specify a TTL to use when sending multicast ICP queries
2839 Only useful when sending to a multicast group.
2840 Because we don't accept ICP replies from random
2841 hosts, you must configure other group members as
2842 peers with the 'multicast-responder' option.
2844 no-delay To prevent access to this neighbor from influencing the
2847 digest-url=URL Tell Squid to fetch the cache digest (if digests are
2848 enabled) for this host from the specified URL rather
2849 than the Squid default location.
2852 ==== CARP OPTIONS ====
2854 carp-key=key-specification
2855 use a different key than the full URL to hash against the peer.
2856 the key-specification is a comma-separated list of the keywords
2857 scheme, host, port, path, params
2858 Order is not important.
2860 ==== ACCELERATOR / REVERSE-PROXY OPTIONS ====
2862 originserver Causes this parent to be contacted as an origin server.
2863 Meant to be used in accelerator setups when the peer
2867 Set the Host header of requests forwarded to this peer.
2868 Useful in accelerator setups where the server (peer)
2869 expects a certain domain name but clients may request
2870 others. ie example.com or www.example.com
2872 no-digest Disable request of cache digests.
2875 Disables requesting ICMP RTT database (NetDB).
2878 ==== AUTHENTICATION OPTIONS ====
2881 If this is a personal/workgroup proxy and your parent
2882 requires proxy authentication.
2884 Note: The string can include URL escapes (i.e. %20 for
2885 spaces). This also means % must be written as %%.
2888 Send login details received from client to this peer.
2889 Both Proxy- and WWW-Authorization headers are passed
2890 without alteration to the peer.
2891 Authentication is not required by Squid for this to work.
2893 Note: This will pass any form of authentication but
2894 only Basic auth will work through a proxy unless the
2895 connection-auth options are also used.
2897 login=PASS Send login details received from client to this peer.
2898 Authentication is not required by this option.
2900 If there are no client-provided authentication headers
2901 to pass on, but username and password are available
2902 from an external ACL user= and password= result tags
2903 they may be sent instead.
2905 Note: To combine this with proxy_auth both proxies must
2906 share the same user database as HTTP only allows for
2907 a single login (one for proxy, one for origin server).
2908 Also be warned this will expose your users proxy
2909 password to the peer. USE WITH CAUTION
2912 Send the username to the upstream cache, but with a
2913 fixed password. This is meant to be used when the peer
2914 is in another administrative domain, but it is still
2915 needed to identify each user.
2916 The star can optionally be followed by some extra
2917 information which is added to the username. This can
2918 be used to identify this proxy to the peer, similar to
2919 the login=username:password option above.
2922 If this is a personal/workgroup proxy and your parent
2923 requires a secure proxy authentication.
2924 The first principal from the default keytab or defined by
2925 the environment variable KRB5_KTNAME will be used.
2927 WARNING: The connection may transmit requests from multiple
2928 clients. Negotiate often assumes end-to-end authentication
2929 and a single-client. Which is not strictly true here.
2931 login=NEGOTIATE:principal_name
2932 If this is a personal/workgroup proxy and your parent
2933 requires a secure proxy authentication.
2934 The principal principal_name from the default keytab or
2935 defined by the environment variable KRB5_KTNAME will be
2938 WARNING: The connection may transmit requests from multiple
2939 clients. Negotiate often assumes end-to-end authentication
2940 and a single-client. Which is not strictly true here.
2942 connection-auth=on|off
2943 Tell Squid that this peer does or not support Microsoft
2944 connection oriented authentication, and any such
2945 challenges received from there should be ignored.
2946 Default is auto to automatically determine the status
2950 ==== SSL / HTTPS / TLS OPTIONS ====
2952 ssl Encrypt connections to this peer with SSL/TLS.
2954 sslcert=/path/to/ssl/certificate
2955 A client SSL certificate to use when connecting to
2958 sslkey=/path/to/ssl/key
2959 The private SSL key corresponding to sslcert above.
2960 If 'sslkey' is not specified 'sslcert' is assumed to
2961 reference a combined file containing both the
2962 certificate and the key.
2964 sslversion=1|2|3|4|5|6
2965 The SSL version to use when connecting to this peer
2966 1 = automatic (default)
2973 sslcipher=... The list of valid SSL ciphers to use when connecting
2976 ssloptions=... Specify various SSL implementation options:
2978 NO_SSLv2 Disallow the use of SSLv2
2979 NO_SSLv3 Disallow the use of SSLv3
2980 NO_TLSv1 Disallow the use of TLSv1.0
2981 NO_TLSv1_1 Disallow the use of TLSv1.1
2982 NO_TLSv1_2 Disallow the use of TLSv1.2
2984 Always create a new key when using
2985 temporary/ephemeral DH key exchanges
2986 ALL Enable various bug workarounds
2987 suggested as "harmless" by OpenSSL
2988 Be warned that this reduces SSL/TLS
2989 strength to some attacks.
2991 See the OpenSSL SSL_CTX_set_options documentation for a
2994 sslcafile=... A file containing additional CA certificates to use
2995 when verifying the peer certificate.
2997 sslcapath=... A directory containing additional CA certificates to
2998 use when verifying the peer certificate.
3000 sslcrlfile=... A certificate revocation list file to use when
3001 verifying the peer certificate.
3003 sslflags=... Specify various flags modifying the SSL implementation:
3006 Accept certificates even if they fail to
3009 Don't use the default CA list built in
3012 Don't verify the peer certificate
3013 matches the server name
3015 ssldomain= The peer name as advertised in it's certificate.
3016 Used for verifying the correctness of the received peer
3017 certificate. If not specified the peer hostname will be
3021 Enable the "Front-End-Https: On" header needed when
3022 using Squid as a SSL frontend in front of Microsoft OWA.
3023 See MS KB document Q307347 for details on this header.
3024 If set to auto the header will only be added if the
3025 request is forwarded as a https:// URL.
3028 ==== GENERAL OPTIONS ====
3031 A peer-specific connect timeout.
3032 Also see the peer_connect_timeout directive.
3034 connect-fail-limit=N
3035 How many times connecting to a peer must fail before
3036 it is marked as down. Standby connection failures
3037 count towards this limit. Default is 10.
3039 allow-miss Disable Squid's use of only-if-cached when forwarding
3040 requests to siblings. This is primarily useful when
3041 icp_hit_stale is used by the sibling. To extensive use
3042 of this option may result in forwarding loops, and you
3043 should avoid having two-way peerings with this option.
3044 For example to deny peer usage on requests from peer
3045 by denying cache_peer_access if the source is a peer.
3047 max-conn=N Limit the number of concurrent connections the Squid
3048 may open to this peer, including already opened idle
3049 and standby connections. There is no peer-specific
3050 connection limit by default.
3052 A peer exceeding the limit is not used for new
3053 requests unless a standby connection is available.
3055 max-conn currently works poorly with idle persistent
3056 connections: When a peer reaches its max-conn limit,
3057 and there are idle persistent connections to the peer,
3058 the peer may not be selected because the limiting code
3059 does not know whether Squid can reuse those idle
3062 standby=N Maintain a pool of N "hot standby" connections to an
3063 UP peer, available for requests when no idle
3064 persistent connection is available (or safe) to use.
3065 By default and with zero N, no such pool is maintained.
3066 N must not exceed the max-conn limit (if any).
3068 At start or after reconfiguration, Squid opens new TCP
3069 standby connections until there are N connections
3070 available and then replenishes the standby pool as
3071 opened connections are used up for requests. A used
3072 connection never goes back to the standby pool, but
3073 may go to the regular idle persistent connection pool
3074 shared by all peers and origin servers.
3076 Squid never opens multiple new standby connections
3077 concurrently. This one-at-a-time approach minimizes
3078 flooding-like effect on peers. Furthermore, just a few
3079 standby connections should be sufficient in most cases
3080 to supply most new requests with a ready-to-use
3083 Standby connections obey server_idle_pconn_timeout.
3084 For the feature to work as intended, the peer must be
3085 configured to accept and keep them open longer than
3086 the idle timeout at the connecting Squid, to minimize
3087 race conditions typical to idle used persistent
3088 connections. Default request_timeout and
3089 server_idle_pconn_timeout values ensure such a
3092 name=xxx Unique name for the peer.
3093 Required if you have multiple peers on the same host
3094 but different ports.
3095 This name can be used in cache_peer_access and similar
3096 directives to dentify the peer.
3097 Can be used by outgoing access controls through the
3100 no-tproxy Do not use the client-spoof TPROXY support when forwarding
3101 requests to this peer. Use normal address selection instead.
3102 This overrides the spoof_client_ip ACL.
3104 proxy-only objects fetched from the peer will not be stored locally.
3108 NAME: cache_peer_domain cache_host_domain
3113 Use to limit the domains for which a neighbor cache will be
3117 cache_peer_domain cache-host domain [domain ...]
3118 cache_peer_domain cache-host !domain
3120 For example, specifying
3122 cache_peer_domain parent.foo.net .edu
3124 has the effect such that UDP query packets are sent to
3125 'bigserver' only when the requested object exists on a
3126 server in the .edu domain. Prefixing the domainname
3127 with '!' means the cache will be queried for objects
3130 NOTE: * Any number of domains may be given for a cache-host,
3131 either on the same or separate lines.
3132 * When multiple domains are given for a particular
3133 cache-host, the first matched domain is applied.
3134 * Cache hosts with no domain restrictions are queried
3136 * There are no defaults.
3137 * There is also a 'cache_peer_access' tag in the ACL
3141 NAME: cache_peer_access
3146 Similar to 'cache_peer_domain' but provides more flexibility by
3150 cache_peer_access cache-host allow|deny [!]aclname ...
3152 The syntax is identical to 'http_access' and the other lists of
3153 ACL elements. See the comments for 'http_access' below, or
3154 the Squid FAQ (http://wiki.squid-cache.org/SquidFaq/SquidAcl).
3157 NAME: neighbor_type_domain
3158 TYPE: hostdomaintype
3160 DEFAULT_DOC: The peer type from cache_peer directive is used for all requests to that peer.
3163 Modify the cache_peer neighbor type when passing requests
3164 about specific domains to the peer.
3167 neighbor_type_domain neighbor parent|sibling domain domain ...
3170 cache_peer foo.example.com parent 3128 3130
3171 neighbor_type_domain foo.example.com sibling .au .de
3173 The above configuration treats all requests to foo.example.com as a
3174 parent proxy unless the request is for a .au or .de ccTLD domain name.
3177 NAME: dead_peer_timeout
3181 LOC: Config.Timeout.deadPeer
3183 This controls how long Squid waits to declare a peer cache
3184 as "dead." If there are no ICP replies received in this
3185 amount of time, Squid will declare the peer dead and not
3186 expect to receive any further ICP replies. However, it
3187 continues to send ICP queries, and will mark the peer as
3188 alive upon receipt of the first subsequent ICP reply.
3190 This timeout also affects when Squid expects to receive ICP
3191 replies from peers. If more than 'dead_peer' seconds have
3192 passed since the last ICP reply was received, Squid will not
3193 expect to receive an ICP reply on the next query. Thus, if
3194 your time between requests is greater than this timeout, you
3195 will see a lot of requests sent DIRECT to origin servers
3196 instead of to your parents.
3199 NAME: forward_max_tries
3202 LOC: Config.forward_max_tries
3204 Controls how many different forward paths Squid will try
3205 before giving up. See also forward_timeout.
3207 NOTE: connect_retries (default: none) can make each of these
3208 possible forwarding paths be tried multiple times.
3212 MEMORY CACHE OPTIONS
3213 -----------------------------------------------------------------------------
3220 LOC: Config.memMaxSize
3222 NOTE: THIS PARAMETER DOES NOT SPECIFY THE MAXIMUM PROCESS SIZE.
3223 IT ONLY PLACES A LIMIT ON HOW MUCH ADDITIONAL MEMORY SQUID WILL
3224 USE AS A MEMORY CACHE OF OBJECTS. SQUID USES MEMORY FOR OTHER
3225 THINGS AS WELL. SEE THE SQUID FAQ SECTION 8 FOR DETAILS.
3227 'cache_mem' specifies the ideal amount of memory to be used
3229 * In-Transit objects
3231 * Negative-Cached objects
3233 Data for these objects are stored in 4 KB blocks. This
3234 parameter specifies the ideal upper limit on the total size of
3235 4 KB blocks allocated. In-Transit objects take the highest
3238 In-transit objects have priority over the others. When
3239 additional space is needed for incoming data, negative-cached
3240 and hot objects will be released. In other words, the
3241 negative-cached and hot objects will fill up any unused space
3242 not needed for in-transit objects.
3244 If circumstances require, this limit will be exceeded.
3245 Specifically, if your incoming request rate requires more than
3246 'cache_mem' of memory to hold in-transit objects, Squid will
3247 exceed this limit to satisfy the new requests. When the load
3248 decreases, blocks will be freed until the high-water mark is
3249 reached. Thereafter, blocks will be used to store hot
3252 If shared memory caching is enabled, Squid does not use the shared
3253 cache space for in-transit objects, but they still consume as much
3254 local memory as they need. For more details about the shared memory
3255 cache, see memory_cache_shared.
3258 NAME: maximum_object_size_in_memory
3262 LOC: Config.Store.maxInMemObjSize
3264 Objects greater than this size will not be attempted to kept in
3265 the memory cache. This should be set high enough to keep objects
3266 accessed frequently in memory to improve performance whilst low
3267 enough to keep larger objects from hoarding cache_mem.
3270 NAME: memory_cache_shared
3273 LOC: Config.memShared
3275 DEFAULT_DOC: "on" where supported if doing memory caching with multiple SMP workers.
3277 Controls whether the memory cache is shared among SMP workers.
3279 The shared memory cache is meant to occupy cache_mem bytes and replace
3280 the non-shared memory cache, although some entities may still be
3281 cached locally by workers for now (e.g., internal and in-transit
3282 objects may be served from a local memory cache even if shared memory
3283 caching is enabled).
3285 By default, the memory cache is shared if and only if all of the
3286 following conditions are satisfied: Squid runs in SMP mode with
3287 multiple workers, cache_mem is positive, and Squid environment
3288 supports required IPC primitives (e.g., POSIX shared memory segments
3289 and GCC-style atomic operations).
3291 To avoid blocking locks, shared memory uses opportunistic algorithms
3292 that do not guarantee that every cachable entity that could have been
3293 shared among SMP workers will actually be shared.
3295 Currently, entities exceeding 32KB in size cannot be shared.
3298 NAME: memory_cache_mode
3302 DEFAULT_DOC: Keep the most recently fetched objects in memory
3304 Controls which objects to keep in the memory cache (cache_mem)
3306 always Keep most recently fetched objects in memory (default)
3308 disk Only disk cache hits are kept in memory, which means
3309 an object must first be cached on disk and then hit
3310 a second time before cached in memory.
3312 network Only objects fetched from network is kept in memory
3315 NAME: memory_replacement_policy
3317 LOC: Config.memPolicy
3320 The memory replacement policy parameter determines which
3321 objects are purged from memory when memory space is needed.
3323 See cache_replacement_policy for details on algorithms.
3328 -----------------------------------------------------------------------------
3331 NAME: cache_replacement_policy
3333 LOC: Config.replPolicy
3336 The cache replacement policy parameter determines which
3337 objects are evicted (replaced) when disk space is needed.
3339 lru : Squid's original list based LRU policy
3340 heap GDSF : Greedy-Dual Size Frequency
3341 heap LFUDA: Least Frequently Used with Dynamic Aging
3342 heap LRU : LRU policy implemented using a heap
3344 Applies to any cache_dir lines listed below this directive.
3346 The LRU policies keeps recently referenced objects.
3348 The heap GDSF policy optimizes object hit rate by keeping smaller
3349 popular objects in cache so it has a better chance of getting a
3350 hit. It achieves a lower byte hit rate than LFUDA though since
3351 it evicts larger (possibly popular) objects.
3353 The heap LFUDA policy keeps popular objects in cache regardless of
3354 their size and thus optimizes byte hit rate at the expense of
3355 hit rate since one large, popular object will prevent many
3356 smaller, slightly less popular objects from being cached.
3358 Both policies utilize a dynamic aging mechanism that prevents
3359 cache pollution that can otherwise occur with frequency-based
3360 replacement policies.
3362 NOTE: if using the LFUDA replacement policy you should increase
3363 the value of maximum_object_size above its default of 4 MB to
3364 to maximize the potential byte hit rate improvement of LFUDA.
3366 For more information about the GDSF and LFUDA cache replacement
3367 policies see http://www.hpl.hp.com/techreports/1999/HPL-1999-69.html
3368 and http://fog.hpl.external.hp.com/techreports/98/HPL-98-173.html.
3371 NAME: minimum_object_size
3375 DEFAULT_DOC: no limit
3376 LOC: Config.Store.minObjectSize
3378 Objects smaller than this size will NOT be saved on disk. The
3379 value is specified in bytes, and the default is 0 KB, which
3380 means all responses can be stored.
3383 NAME: maximum_object_size
3387 LOC: Config.Store.maxObjectSize
3389 Set the default value for max-size parameter on any cache_dir.
3390 The value is specified in bytes, and the default is 4 MB.
3392 If you wish to get a high BYTES hit ratio, you should probably
3393 increase this (one 32 MB object hit counts for 3200 10KB
3396 If you wish to increase hit ratio more than you want to
3397 save bandwidth you should leave this low.
3399 NOTE: if using the LFUDA replacement policy you should increase
3400 this value to maximize the byte hit rate improvement of LFUDA!
3401 See cache_replacement_policy for a discussion of this policy.
3407 DEFAULT_DOC: No disk cache. Store cache ojects only in memory.
3408 LOC: Config.cacheSwap
3411 cache_dir Type Directory-Name Fs-specific-data [options]
3413 You can specify multiple cache_dir lines to spread the
3414 cache among different disk partitions.
3416 Type specifies the kind of storage system to use. Only "ufs"
3417 is built by default. To enable any of the other storage systems
3418 see the --enable-storeio configure option.
3420 'Directory' is a top-level directory where cache swap
3421 files will be stored. If you want to use an entire disk
3422 for caching, this can be the mount-point directory.
3423 The directory must exist and be writable by the Squid
3424 process. Squid will NOT create this directory for you.
3426 In SMP configurations, cache_dir must not precede the workers option
3427 and should use configuration macros or conditionals to give each
3428 worker interested in disk caching a dedicated cache directory.
3431 ==== The ufs store type ====
3433 "ufs" is the old well-known Squid storage format that has always
3437 cache_dir ufs Directory-Name Mbytes L1 L2 [options]
3439 'Mbytes' is the amount of disk space (MB) to use under this
3440 directory. The default is 100 MB. Change this to suit your
3441 configuration. Do NOT put the size of your disk drive here.
3442 Instead, if you want Squid to use the entire disk drive,
3443 subtract 20% and use that value.
3445 'L1' is the number of first-level subdirectories which
3446 will be created under the 'Directory'. The default is 16.
3448 'L2' is the number of second-level subdirectories which
3449 will be created under each first-level directory. The default
3453 ==== The aufs store type ====
3455 "aufs" uses the same storage format as "ufs", utilizing
3456 POSIX-threads to avoid blocking the main Squid process on
3457 disk-I/O. This was formerly known in Squid as async-io.
3460 cache_dir aufs Directory-Name Mbytes L1 L2 [options]
3462 see argument descriptions under ufs above
3465 ==== The diskd store type ====
3467 "diskd" uses the same storage format as "ufs", utilizing a
3468 separate process to avoid blocking the main Squid process on
3472 cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n]
3474 see argument descriptions under ufs above
3476 Q1 specifies the number of unacknowledged I/O requests when Squid
3477 stops opening new files. If this many messages are in the queues,
3478 Squid won't open new files. Default is 64
3480 Q2 specifies the number of unacknowledged messages when Squid
3481 starts blocking. If this many messages are in the queues,
3482 Squid blocks until it receives some replies. Default is 72
3484 When Q1 < Q2 (the default), the cache directory is optimized
3485 for lower response time at the expense of a decrease in hit
3486 ratio. If Q1 > Q2, the cache directory is optimized for
3487 higher hit ratio at the expense of an increase in response
3491 ==== The rock store type ====
3494 cache_dir rock Directory-Name Mbytes [options]
3496 The Rock Store type is a database-style storage. All cached
3497 entries are stored in a "database" file, using fixed-size slots.
3498 A single entry occupies one or more slots.
3500 If possible, Squid using Rock Store creates a dedicated kid
3501 process called "disker" to avoid blocking Squid worker(s) on disk
3502 I/O. One disker kid is created for each rock cache_dir. Diskers
3503 are created only when Squid, running in daemon mode, has support
3504 for the IpcIo disk I/O module.
3506 swap-timeout=msec: Squid will not start writing a miss to or
3507 reading a hit from disk if it estimates that the swap operation
3508 will take more than the specified number of milliseconds. By
3509 default and when set to zero, disables the disk I/O time limit
3510 enforcement. Ignored when using blocking I/O module because
3511 blocking synchronous I/O does not allow Squid to estimate the
3512 expected swap wait time.
3514 max-swap-rate=swaps/sec: Artificially limits disk access using
3515 the specified I/O rate limit. Swap out requests that
3516 would cause the average I/O rate to exceed the limit are
3517 delayed. Individual swap in requests (i.e., hits or reads) are
3518 not delayed, but they do contribute to measured swap rate and
3519 since they are placed in the same FIFO queue as swap out
3520 requests, they may wait longer if max-swap-rate is smaller.
3521 This is necessary on file systems that buffer "too
3522 many" writes and then start blocking Squid and other processes
3523 while committing those writes to disk. Usually used together
3524 with swap-timeout to avoid excessive delays and queue overflows
3525 when disk demand exceeds available disk "bandwidth". By default
3526 and when set to zero, disables the disk I/O rate limit
3527 enforcement. Currently supported by IpcIo module only.
3529 slot-size=bytes: The size of a database "record" used for
3530 storing cached responses. A cached response occupies at least
3531 one slot and all database I/O is done using individual slots so
3532 increasing this parameter leads to more disk space waste while
3533 decreasing it leads to more disk I/O overheads. Should be a
3534 multiple of your operating system I/O page size. Defaults to
3535 16KBytes. A housekeeping header is stored with each slot and
3536 smaller slot-sizes will be rejected. The header is smaller than
3540 ==== COMMON OPTIONS ====
3542 no-store no new objects should be stored to this cache_dir.
3544 min-size=n the minimum object size in bytes this cache_dir
3545 will accept. It's used to restrict a cache_dir
3546 to only store large objects (e.g. AUFS) while
3547 other stores are optimized for smaller objects
3551 max-size=n the maximum object size in bytes this cache_dir
3553 The value in maximum_object_size directive sets
3554 the default unless more specific details are
3555 available (ie a small store capacity).
3557 Note: To make optimal use of the max-size limits you should order
3558 the cache_dir lines with the smallest max-size value first.
3562 # Uncomment and adjust the following to add a disk cache directory.
3563 #cache_dir ufs @DEFAULT_SWAP_DIR@ 100 16 256
3567 NAME: store_dir_select_algorithm
3569 LOC: Config.store_dir_select_algorithm
3572 How Squid selects which cache_dir to use when the response
3573 object will fit into more than one.
3575 Regardless of which algorithm is used the cache_dir min-size
3576 and max-size parameters are obeyed. As such they can affect
3577 the selection algorithm by limiting the set of considered
3584 This algorithm is suited to caches with similar cache_dir
3585 sizes and disk speeds.
3587 The disk with the least I/O pending is selected.
3588 When there are multiple disks with the same I/O load ranking
3589 the cache_dir with most available capacity is selected.
3591 When a mix of cache_dir sizes are configured the faster disks
3592 have a naturally lower I/O loading and larger disks have more
3593 capacity. So space used to store objects and data throughput
3594 may be very unbalanced towards larger disks.
3599 This algorithm is suited to caches with unequal cache_dir
3602 Each cache_dir is selected in a rotation. The next suitable
3605 Available cache_dir capacity is only considered in relation
3606 to whether the object will fit and meets the min-size and
3607 max-size parameters.
3609 Disk I/O loading is only considered to prevent overload on slow
3610 disks. This algorithm does not spread objects by size, so any
3611 I/O loading per-disk may appear very unbalanced and volatile.
3613 If several cache_dirs use similar min-size, max-size, or other
3614 limits to to reject certain responses, then do not group such
3615 cache_dir lines together, to avoid round-robin selection bias
3616 towards the first cache_dir after the group. Instead, interleave
3617 cache_dir lines from different groups. For example:
3619 store_dir_select_algorithm round-robin
3620 cache_dir rock /hdd1 ... min-size=100000
3621 cache_dir rock /ssd1 ... max-size=99999
3622 cache_dir rock /hdd2 ... min-size=100000
3623 cache_dir rock /ssd2 ... max-size=99999
3624 cache_dir rock /hdd3 ... min-size=100000
3625 cache_dir rock /ssd3 ... max-size=99999
3628 NAME: max_open_disk_fds
3630 LOC: Config.max_open_disk_fds
3632 DEFAULT_DOC: no limit
3634 To avoid having disk as the I/O bottleneck Squid can optionally
3635 bypass the on-disk cache if more than this amount of disk file
3636 descriptors are open.
3638 A value of 0 indicates no limit.
3641 NAME: cache_swap_low
3642 COMMENT: (percent, 0-100)
3645 LOC: Config.Swap.lowWaterMark
3647 The low-water mark for cache object replacement.
3648 Replacement begins when the swap (disk) usage is above the
3649 low-water mark and attempts to maintain utilization near the
3650 low-water mark. As swap utilization gets close to high-water
3651 mark object eviction becomes more aggressive. If utilization is
3652 close to the low-water mark less replacement is done each time.
3654 Defaults are 90% and 95%. If you have a large cache, 5% could be
3655 hundreds of MB. If this is the case you may wish to set these
3656 numbers closer together.
3658 See also cache_swap_high
3661 NAME: cache_swap_high
3662 COMMENT: (percent, 0-100)
3665 LOC: Config.Swap.highWaterMark
3667 The high-water mark for cache object replacement.
3668 Replacement begins when the swap (disk) usage is above the
3669 low-water mark and attempts to maintain utilization near the
3670 low-water mark. As swap utilization gets close to high-water
3671 mark object eviction becomes more aggressive. If utilization is
3672 close to the low-water mark less replacement is done each time.
3674 Defaults are 90% and 95%. If you have a large cache, 5% could be
3675 hundreds of MB. If this is the case you may wish to set these
3676 numbers closer together.
3678 See also cache_swap_low
3683 -----------------------------------------------------------------------------
3690 DEFAULT_DOC: The format definitions squid, common, combined, referrer, useragent are built in.
3694 logformat <name> <format specification>
3696 Defines an access log format.
3698 The <format specification> is a string with embedded % format codes
3700 % format codes all follow the same basic structure where all but
3701 the formatcode is optional. Output strings are automatically escaped
3702 as required according to their context and the output format
3703 modifiers are usually not needed, but can be specified if an explicit
3704 output format is desired.
3706 % ["|[|'|#] [-] [[0]width] [{argument}] formatcode
3708 " output in quoted string format
3709 [ output in squid text log format as used by log_mime_hdrs
3710 # output in URL quoted format
3715 width minimum and/or maximum field width:
3716 [width_min][.width_max]
3717 When minimum starts with 0, the field is zero-padded.
3718 String values exceeding maximum width are truncated.
3720 {arg} argument such as header name etc
3724 % a literal % character
3725 sn Unique sequence number per log line entry
3726 err_code The ID of an error response served by Squid or
3727 a similar internal error identifier.
3728 err_detail Additional err_code-dependent error information.
3729 note The annotation specified by the argument. Also
3730 logs the adaptation meta headers set by the
3731 adaptation_meta configuration parameter.
3732 If no argument given all annotations logged.
3733 The argument may include a separator to use with
3736 By default, multiple note values are separated with ","
3737 and multiple notes are separated with "\r\n".
3738 When logging named notes with %{name}note, the
3739 explicitly configured separator is used between note
3740 values. When logging all notes with %note, the
3741 explicitly configured separator is used between
3742 individual notes. There is currently no way to
3743 specify both value and notes separators when logging
3744 all notes with %note.
3746 Connection related format codes:
3748 >a Client source IP address
3750 >p Client source port
3751 >eui Client source EUI (MAC address, EUI-48 or EUI-64 identifier)
3752 >la Local IP address the client connected to
3753 >lp Local port number the client connected to
3754 >qos Client connection TOS/DSCP value set by Squid
3755 >nfmark Client connection netfilter mark set by Squid
3757 la Local listening IP address the client connection was connected to.
3758 lp Local listening port number the client connection was connected to.
3760 <a Server IP address of the last server or peer connection
3761 <A Server FQDN or peer name
3762 <p Server port number of the last server or peer connection
3763 <la Local IP address of the last server or peer connection
3764 <lp Local port number of the last server or peer connection
3765 <qos Server connection TOS/DSCP value set by Squid
3766 <nfmark Server connection netfilter mark set by Squid
3768 Time related format codes:
3770 ts Seconds since epoch
3771 tu subsecond time (milliseconds)
3772 tl Local time. Optional strftime format argument
3773 default %d/%b/%Y:%H:%M:%S %z
3774 tg GMT time. Optional strftime format argument
3775 default %d/%b/%Y:%H:%M:%S %z
3776 tr Response time (milliseconds)
3777 dt Total time spent making DNS lookups (milliseconds)
3778 tS Approximate master transaction start time in
3779 <full seconds since epoch>.<fractional seconds> format.
3780 Currently, Squid considers the master transaction
3781 started when a complete HTTP request header initiating
3782 the transaction is received from the client. This is
3783 the same value that Squid uses to calculate transaction
3784 response time when logging %tr to access.log. Currently,
3785 Squid uses millisecond resolution for %tS values,
3786 similar to the default access.log "current time" field
3789 Access Control related format codes:
3791 et Tag returned by external acl
3792 ea Log string returned by external acl
3793 un User name (any available)
3794 ul User name from authentication
3795 ue User name from external acl helper
3796 ui User name from ident
3797 us User name from SSL
3798 credentials Client credentials. The exact meaning depends on
3799 the authentication scheme: For Basic authentication,
3800 it is the password; for Digest, the realm sent by the
3801 client; for NTLM and Negotiate, the client challenge
3802 or client credentials prefixed with "YR " or "KK ".
3804 HTTP related format codes:
3808 [http::]rm Request method (GET/POST etc)
3809 [http::]>rm Request method from client
3810 [http::]<rm Request method sent to server or peer
3811 [http::]ru Request URL from client (historic, filtered for logging)
3812 [http::]>ru Request URL from client
3813 [http::]<ru Request URL sent to server or peer
3814 [http::]>rs Request URL scheme from client
3815 [http::]<rs Request URL scheme sent to server or peer
3816 [http::]>rd Request URL domain from client
3817 [http::]>rd Request URL domain sent to server or peer
3818 [http::]>rP Request URL port from client
3819 [http::]<rP Request URL port sent to server or peer
3820 [http::]rp Request URL path excluding hostname
3821 [http::]>rp Request URL path excluding hostname from client
3822 [http::]<rp Request URL path excluding hostname sent to server or peer
3823 [http::]rv Request protocol version
3824 [http::]>rv Request protocol version from client
3825 [http::]<rv Request protocol version sent to server or peer
3827 [http::]>h Original received request header.
3828 Usually differs from the request header sent by
3829 Squid, although most fields are often preserved.
3830 Accepts optional header field name/value filter
3831 argument using name[:[separator]element] format.
3832 [http::]>ha Received request header after adaptation and
3833 redirection (pre-cache REQMOD vectoring point).
3834 Usually differs from the request header sent by
3835 Squid, although most fields are often preserved.
3836 Optional header name argument as for >h
3841 [http::]<Hs HTTP status code received from the next hop
3842 [http::]>Hs HTTP status code sent to the client
3844 [http::]<h Reply header. Optional header name argument
3847 [http::]mt MIME content type
3852 [http::]st Total size of request + reply traffic with client
3853 [http::]>st Total size of request received from client.
3854 Excluding chunked encoding bytes.
3855 [http::]<st Total size of reply sent to client (after adaptation)
3857 [http::]>sh Size of request headers received from client
3858 [http::]<sh Size of reply headers sent to client (after adaptation)
3860 [http::]<sH Reply high offset sent
3861 [http::]<sS Upstream object size
3863 [http::]<bs Number of HTTP-equivalent message body bytes
3864 received from the next hop, excluding chunked
3865 transfer encoding and control messages.
3866 Generated FTP/Gopher listings are treated as
3872 [http::]<pt Peer response time in milliseconds. The timer starts
3873 when the last request byte is sent to the next hop
3874 and stops when the last response byte is received.
3875 [http::]<tt Total server-side time in milliseconds. The timer
3876 starts with the first connect request (or write I/O)
3877 sent to the first selected peer. The timer stops
3878 with the last I/O with the last peer.
3880 Squid handling related format codes:
3882 Ss Squid request status (TCP_MISS etc)
3883 Sh Squid hierarchy status (DEFAULT_PARENT etc)
3885 SSL-related format codes:
3887 ssl::bump_mode SslBump decision for the transaction:
3889 For CONNECT requests that initiated bumping of
3890 a connection and for any request received on
3891 an already bumped connection, Squid logs the
3892 corresponding SslBump mode ("server-first" or
3893 "client-first"). See the ssl_bump option for
3894 more information about these modes.
3896 A "none" token is logged for requests that
3897 triggered "ssl_bump" ACL evaluation matching
3898 either a "none" rule or no rules at all.
3900 In all other cases, a single dash ("-") is
3903 If ICAP is enabled, the following code becomes available (as
3904 well as ICAP log codes documented with the icap_log option):
3906 icap::tt Total ICAP processing time for the HTTP
3907 transaction. The timer ticks when ICAP
3908 ACLs are checked and when ICAP
3909 transaction is in progress.
3911 If adaptation is enabled the following three codes become available:
3913 adapt::<last_h The header of the last ICAP response or
3914 meta-information from the last eCAP
3915 transaction related to the HTTP transaction.
3916 Like <h, accepts an optional header name
3919 adapt::sum_trs Summed adaptation transaction response
3920 times recorded as a comma-separated list in
3921 the order of transaction start time. Each time
3922 value is recorded as an integer number,
3923 representing response time of one or more
3924 adaptation (ICAP or eCAP) transaction in
3925 milliseconds. When a failed transaction is
3926 being retried or repeated, its time is not
3927 logged individually but added to the
3928 replacement (next) transaction. See also:
3931 adapt::all_trs All adaptation transaction response times.
3932 Same as adaptation_strs but response times of
3933 individual transactions are never added
3934 together. Instead, all transaction response
3935 times are recorded individually.
3937 You can prefix adapt::*_trs format codes with adaptation
3938 service name in curly braces to record response time(s) specific
3939 to that service. For example: %{my_service}adapt::sum_trs
3941 If SSL is enabled, the following formating codes become available:
3943 %ssl::>cert_subject The Subject field of the received client
3944 SSL certificate or a dash ('-') if Squid has
3945 received an invalid/malformed certificate or
3946 no certificate at all. Consider encoding the
3947 logged value because Subject often has spaces.
3949 %ssl::>cert_issuer The Issuer field of the received client
3950 SSL certificate or a dash ('-') if Squid has
3951 received an invalid/malformed certificate or
3952 no certificate at all. Consider encoding the
3953 logged value because Issuer often has spaces.
3955 The default formats available (which do not need re-defining) are:
3957 logformat squid %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %[un %Sh/%<a %mt
3958 logformat common %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st %Ss:%Sh
3959 logformat combined %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
3960 logformat referrer %ts.%03tu %>a %{Referer}>h %ru
3961 logformat useragent %>a [%tl] "%{User-Agent}>h"
3963 NOTE: When the log_mime_hdrs directive is set to ON.
3964 The squid, common and combined formats have a safely encoded copy
3965 of the mime headers appended to each line within a pair of brackets.
3967 NOTE: The common and combined formats are not quite true to the Apache definition.
3968 The logs from Squid contain an extra status and hierarchy code appended.
3972 NAME: access_log cache_access_log
3974 LOC: Config.Log.accesslogs
3975 DEFAULT_IF_NONE: daemon:@DEFAULT_ACCESS_LOG@ squid
3977 Configures whether and how Squid logs HTTP and ICP transactions.
3978 If access logging is enabled, a single line is logged for every
3979 matching HTTP or ICP request. The recommended directive formats are:
3981 access_log <module>:<place> [option ...] [acl acl ...]
3982 access_log none [acl acl ...]
3984 The following directive format is accepted but may be deprecated:
3985 access_log <module>:<place> [<logformat name> [acl acl ...]]
3987 In most cases, the first ACL name must not contain the '=' character
3988 and should not be equal to an existing logformat name. You can always
3989 start with an 'all' ACL to work around those restrictions.
3991 Will log to the specified module:place using the specified format (which
3992 must be defined in a logformat directive) those entries which match
3993 ALL the acl's specified (which must be defined in acl clauses).
3994 If no acl is specified, all requests will be logged to this destination.
3996 ===== Available options for the recommended directive format =====
3998 logformat=name Names log line format (either built-in or
3999 defined by a logformat directive). Defaults
4002 buffer-size=64KB Defines approximate buffering limit for log
4003 records (see buffered_logs). Squid should not
4004 keep more than the specified size and, hence,
4005 should flush records before the buffer becomes
4006 full to avoid overflows under normal
4007 conditions (the exact flushing algorithm is
4008 module-dependent though). The on-error option
4009 controls overflow handling.
4011 on-error=die|drop Defines action on unrecoverable errors. The
4012 'drop' action ignores (i.e., does not log)
4013 affected log records. The default 'die' action
4014 kills the affected worker. The drop action
4015 support has not been tested for modules other
4018 ===== Modules Currently available =====
4020 none Do not log any requests matching these ACL.
4021 Do not specify Place or logformat name.
4023 stdio Write each log line to disk immediately at the completion of
4025 Place: the filename and path to be written.
4027 daemon Very similar to stdio. But instead of writing to disk the log
4028 line is passed to a daemon helper for asychronous handling instead.
4029 Place: varies depending on the daemon.
4031 log_file_daemon Place: the file name and path to be written.
4033 syslog To log each request via syslog facility.
4034 Place: The syslog facility and priority level for these entries.
4035 Place Format: facility.priority
4037 where facility could be any of:
4038 authpriv, daemon, local0 ... local7 or user.
4040 And priority could be any of:
4041 err, warning, notice, info, debug.
4043 udp To send each log line as text data to a UDP receiver.
4044 Place: The destination host name or IP and port.
4045 Place Format: //host:port
4047 tcp To send each log line as text data to a TCP receiver.
4048 Lines may be accumulated before sending (see buffered_logs).
4049 Place: The destination host name or IP and port.
4050 Place Format: //host:port
4053 access_log daemon:@DEFAULT_ACCESS_LOG@ squid
4059 LOC: Config.Log.icaplogs
4062 ICAP log files record ICAP transaction summaries, one line per
4065 The icap_log option format is:
4066 icap_log <filepath> [<logformat name> [acl acl ...]]
4067 icap_log none [acl acl ...]]
4069 Please see access_log option documentation for details. The two
4070 kinds of logs share the overall configuration approach and many
4073 ICAP processing of a single HTTP message or transaction may
4074 require multiple ICAP transactions. In such cases, multiple
4075 ICAP transaction log lines will correspond to a single access
4078 ICAP log uses logformat codes that make sense for an ICAP
4079 transaction. Header-related codes are applied to the HTTP header
4080 embedded in an ICAP server response, with the following caveats:
4081 For REQMOD, there is no HTTP response header unless the ICAP
4082 server performed request satisfaction. For RESPMOD, the HTTP
4083 request header is the header sent to the ICAP server. For
4084 OPTIONS, there are no HTTP headers.
4086 The following format codes are also available for ICAP logs:
4088 icap::<A ICAP server IP address. Similar to <A.
4090 icap::<service_name ICAP service name from the icap_service
4091 option in Squid configuration file.
4093 icap::ru ICAP Request-URI. Similar to ru.
4095 icap::rm ICAP request method (REQMOD, RESPMOD, or
4096 OPTIONS). Similar to existing rm.
4098 icap::>st Bytes sent to the ICAP server (TCP payload
4099 only; i.e., what Squid writes to the socket).
4101 icap::<st Bytes received from the ICAP server (TCP
4102 payload only; i.e., what Squid reads from
4105 icap::<bs Number of message body bytes received from the
4106 ICAP server. ICAP message body, if any, usually
4107 includes encapsulated HTTP message headers and
4108 possibly encapsulated HTTP message body. The
4109 HTTP body part is dechunked before its size is
4112 icap::tr Transaction response time (in
4113 milliseconds). The timer starts when
4114 the ICAP transaction is created and
4115 stops when the transaction is completed.
4118 icap::tio Transaction I/O time (in milliseconds). The
4119 timer starts when the first ICAP request
4120 byte is scheduled for sending. The timers
4121 stops when the last byte of the ICAP response
4124 icap::to Transaction outcome: ICAP_ERR* for all
4125 transaction errors, ICAP_OPT for OPTION
4126 transactions, ICAP_ECHO for 204
4127 responses, ICAP_MOD for message
4128 modification, and ICAP_SAT for request
4129 satisfaction. Similar to Ss.
4131 icap::Hs ICAP response status code. Similar to Hs.
4133 icap::>h ICAP request header(s). Similar to >h.
4135 icap::<h ICAP response header(s). Similar to <h.
4137 The default ICAP log format, which can be used without an explicit
4138 definition, is called icap_squid:
4140 logformat icap_squid %ts.%03tu %6icap::tr %>a %icap::to/%03icap::Hs %icap::<size %icap::rm %icap::ru% %un -/%icap::<A -
4142 See also: logformat, log_icap, and %adapt::<last_h
4145 NAME: logfile_daemon
4147 DEFAULT: @DEFAULT_LOGFILED@
4148 LOC: Log::TheConfig.logfile_daemon
4150 Specify the path to the logfile-writing daemon. This daemon is
4151 used to write the access and store logs, if configured.
4153 Squid sends a number of commands to the log daemon:
4154 L<data>\n - logfile data
4159 r<n>\n - set rotate count to <n>
4160 b<n>\n - 1 = buffer output, 0 = don't buffer output
4162 No responses is expected.
4165 NAME: stats_collection
4167 LOC: Config.accessList.stats_collection
4169 DEFAULT_DOC: Allow logging for all transactions.
4170 COMMENT: allow|deny acl acl...
4172 This options allows you to control which requests gets accounted
4173 in performance counters.
4175 This clause only supports fast acl types.
4176 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4179 NAME: cache_store_log
4182 LOC: Config.Log.store
4184 Logs the activities of the storage manager. Shows which
4185 objects are ejected from the cache, and which objects are
4186 saved and for how long.
4187 There are not really utilities to analyze this data, so you can safely
4188 disable it (the default).
4190 Store log uses modular logging outputs. See access_log for the list
4191 of modules supported.
4194 cache_store_log stdio:@DEFAULT_STORE_LOG@
4195 cache_store_log daemon:@DEFAULT_STORE_LOG@
4198 NAME: cache_swap_state cache_swap_log
4200 LOC: Config.Log.swap
4202 DEFAULT_DOC: Store the journal inside its cache_dir
4204 Location for the cache "swap.state" file. This index file holds
4205 the metadata of objects saved on disk. It is used to rebuild
4206 the cache during startup. Normally this file resides in each
4207 'cache_dir' directory, but you may specify an alternate
4208 pathname here. Note you must give a full filename, not just
4209 a directory. Since this is the index for the whole object
4210 list you CANNOT periodically rotate it!
4212 If %s can be used in the file name it will be replaced with a
4213 a representation of the cache_dir name where each / is replaced
4214 with '.'. This is needed to allow adding/removing cache_dir
4215 lines when cache_swap_log is being used.
4217 If have more than one 'cache_dir', and %s is not used in the name
4218 these swap logs will have names such as:
4224 The numbered extension (which is added automatically)
4225 corresponds to the order of the 'cache_dir' lines in this
4226 configuration file. If you change the order of the 'cache_dir'
4227 lines in this file, these index files will NOT correspond to
4228 the correct 'cache_dir' entry (unless you manually rename
4229 them). We recommend you do NOT use this option. It is
4230 better to keep these index files in each 'cache_dir' directory.
4233 NAME: logfile_rotate
4236 LOC: Config.Log.rotateNumber
4238 Specifies the number of logfile rotations to make when you
4239 type 'squid -k rotate'. The default is 10, which will rotate
4240 with extensions 0 through 9. Setting logfile_rotate to 0 will
4241 disable the file name rotation, but the logfiles are still closed
4242 and re-opened. This will enable you to rename the logfiles
4243 yourself just before sending the rotate signal.
4245 Note, the 'squid -k rotate' command normally sends a USR1
4246 signal to the running squid process. In certain situations
4247 (e.g. on Linux with Async I/O), USR1 is used for other
4248 purposes, so -k rotate uses another signal. It is best to get
4249 in the habit of using 'squid -k rotate' instead of 'kill -USR1
4252 Note, from Squid-3.1 this option is only a default for cache.log,
4253 that log can be rotated separately by using debug_options.
4258 DEFAULT: @DEFAULT_MIME_TABLE@
4259 LOC: Config.mimeTablePathname
4261 Path to Squid's icon configuration file.
4263 You shouldn't need to change this, but the default file contains
4264 examples and formatting information if you do.
4270 LOC: Config.onoff.log_mime_hdrs
4273 The Cache can record both the request and the response MIME
4274 headers for each HTTP transaction. The headers are encoded
4275 safely and will appear as two bracketed fields at the end of
4276 the access log (for either the native or httpd-emulated log
4277 formats). To enable this logging set log_mime_hdrs to 'on'.
4282 DEFAULT: @DEFAULT_PID_FILE@
4283 LOC: Config.pidFilename
4285 A filename to write the process-id to. To disable, enter "none".
4288 NAME: client_netmask
4290 LOC: Config.Addrs.client_netmask
4292 DEFAULT_DOC: Log full client IP address
4294 A netmask for client addresses in logfiles and cachemgr output.
4295 Change this to protect the privacy of your cache clients.
4296 A netmask of 255.255.255.0 will log all IP's in that range with
4297 the last digit set to '0'.
4300 NAME: strip_query_terms
4302 LOC: Config.onoff.strip_query_terms
4305 By default, Squid strips query terms from requested URLs before
4306 logging. This protects your user's privacy and reduces log size.
4308 When investigating HIT/MISS or other caching behaviour you
4309 will need to disable this to see the full URL used by Squid.
4316 LOC: Config.onoff.buffered_logs
4318 Whether to write/send access_log records ASAP or accumulate them and
4319 then write/send them in larger chunks. Buffering may improve
4320 performance because it decreases the number of I/Os. However,
4321 buffering increases the delay before log records become available to
4322 the final recipient (e.g., a disk file or logging daemon) and,
4323 hence, increases the risk of log records loss.
4325 Note that even when buffered_logs are off, Squid may have to buffer
4326 records if it cannot write/send them immediately due to pending I/Os
4327 (e.g., the I/O writing the previous log record) or connectivity loss.
4329 Currently honored by 'daemon' and 'tcp' access_log modules only.
4332 NAME: netdb_filename
4334 DEFAULT: stdio:@DEFAULT_NETDB_FILE@
4335 LOC: Config.netdbFilename
4338 Where Squid stores it's netdb journal.
4339 When enabled this journal preserves netdb state between restarts.
4341 To disable, enter "none".
4345 OPTIONS FOR TROUBLESHOOTING
4346 -----------------------------------------------------------------------------
4351 DEFAULT_IF_NONE: @DEFAULT_CACHE_LOG@
4352 LOC: Debug::cache_log
4354 Squid administrative logging file.
4356 This is where general information about Squid behavior goes. You can
4357 increase the amount of data logged to this file and how often it is
4358 rotated with "debug_options"
4364 DEFAULT_DOC: Log all critical and important messages.
4365 LOC: Debug::debugOptions
4367 Logging options are set as section,level where each source file
4368 is assigned a unique section. Lower levels result in less
4369 output, Full debugging (level 9) can result in a very large
4370 log file, so be careful.
4372 The magic word "ALL" sets debugging levels for all sections.
4373 The default is to run with "ALL,1" to record important warnings.
4375 The rotate=N option can be used to keep more or less of these logs
4376 than would otherwise be kept by logfile_rotate.
4377 For most uses a single log should be enough to monitor current
4378 events affecting Squid.
4383 LOC: Config.coredump_dir
4384 DEFAULT_IF_NONE: none
4385 DEFAULT_DOC: Use the directory from where Squid was started.
4387 By default Squid leaves core files in the directory from where
4388 it was started. If you set 'coredump_dir' to a directory
4389 that exists, Squid will chdir() to that directory at startup
4390 and coredump files will be left there.
4394 # Leave coredumps in the first cache dir
4395 coredump_dir @DEFAULT_SWAP_DIR@
4401 OPTIONS FOR FTP GATEWAYING
4402 -----------------------------------------------------------------------------
4408 LOC: Config.Ftp.anon_user
4410 If you want the anonymous login password to be more informative
4411 (and enable the use of picky FTP servers), set this to something
4412 reasonable for your domain, like wwwuser@somewhere.net
4414 The reason why this is domainless by default is the
4415 request can be made on the behalf of a user in any domain,
4416 depending on how the cache is used.
4417 Some FTP server also validate the email address is valid
4418 (for example perl.com).
4424 LOC: Config.Ftp.passive
4426 If your firewall does not allow Squid to use passive
4427 connections, turn off this option.
4429 Use of ftp_epsv_all option requires this to be ON.
4435 LOC: Config.Ftp.epsv_all
4437 FTP Protocol extensions permit the use of a special "EPSV ALL" command.
4439 NATs may be able to put the connection on a "fast path" through the
4440 translator, as the EPRT command will never be used and therefore,
4441 translation of the data portion of the segments will never be needed.
4443 When a client only expects to do two-way FTP transfers this may be
4445 If squid finds that it must do a three-way FTP transfer after issuing
4446 an EPSV ALL command, the FTP session will fail.
4448 If you have any doubts about this option do not use it.
4449 Squid will nicely attempt all other connection methods.
4451 Requires ftp_passive to be ON (default) for any effect.
4457 LOC: Config.accessList.ftp_epsv
4459 FTP Protocol extensions permit the use of a special "EPSV" command.
4461 NATs may be able to put the connection on a "fast path" through the
4462 translator using EPSV, as the EPRT command will never be used
4463 and therefore, translation of the data portion of the segments
4464 will never be needed.
4466 EPSV is often required to interoperate with FTP servers on IPv6
4467 networks. On the other hand, it may break some IPv4 servers.
4469 By default, EPSV may try EPSV with any FTP server. To fine tune
4470 that decision, you may restrict EPSV to certain clients or servers
4473 ftp_epsv allow|deny al1 acl2 ...
4475 WARNING: Disabling EPSV may cause problems with external NAT and IPv6.
4477 Only fast ACLs are supported.
4478 Requires ftp_passive to be ON (default) for any effect.
4484 LOC: Config.Ftp.eprt
4486 FTP Protocol extensions permit the use of a special "EPRT" command.
4488 This extension provides a protocol neutral alternative to the
4489 IPv4-only PORT command. When supported it enables active FTP data
4490 channels over IPv6 and efficient NAT handling.
4492 Turning this OFF will prevent EPRT being attempted and will skip
4493 straight to using PORT for IPv4 servers.
4495 Some devices are known to not handle this extension correctly and
4496 may result in crashes. Devices which suport EPRT enough to fail
4497 cleanly will result in Squid attempting PORT anyway. This directive
4498 should only be disabled when EPRT results in device failures.
4500 WARNING: Doing so will convert Squid back to the old behavior with all
4501 the related problems with external NAT devices/layers and IPv4-only FTP.
4504 NAME: ftp_sanitycheck
4507 LOC: Config.Ftp.sanitycheck
4509 For security and data integrity reasons Squid by default performs
4510 sanity checks of the addresses of FTP data connections ensure the
4511 data connection is to the requested server. If you need to allow
4512 FTP connections to servers using another IP address for the data
4513 connection turn this off.
4516 NAME: ftp_telnet_protocol
4519 LOC: Config.Ftp.telnet
4521 The FTP protocol is officially defined to use the telnet protocol
4522 as transport channel for the control connection. However, many
4523 implementations are broken and does not respect this aspect of
4526 If you have trouble accessing files with ASCII code 255 in the
4527 path or similar problems involving this ASCII code you can
4528 try setting this directive to off. If that helps, report to the
4529 operator of the FTP server in question that their FTP server
4530 is broken and does not follow the FTP standard.
4534 OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
4535 -----------------------------------------------------------------------------
4540 DEFAULT: @DEFAULT_DISKD@
4541 LOC: Config.Program.diskd
4543 Specify the location of the diskd executable.
4544 Note this is only useful if you have compiled in
4545 diskd as one of the store io modules.
4548 NAME: unlinkd_program
4551 DEFAULT: @DEFAULT_UNLINKD@
4552 LOC: Config.Program.unlinkd
4554 Specify the location of the executable for file deletion process.
4557 NAME: pinger_program
4559 DEFAULT: @DEFAULT_PINGER@
4560 LOC: Config.pinger.program
4563 Specify the location of the executable for the pinger process.
4569 LOC: Config.pinger.enable
4572 Control whether the pinger is active at run-time.
4573 Enables turning ICMP pinger on and off with a simple
4574 squid -k reconfigure.
4579 OPTIONS FOR URL REWRITING
4580 -----------------------------------------------------------------------------
4583 NAME: url_rewrite_program redirect_program
4585 LOC: Config.Program.redirect
4588 Specify the location of the executable URL rewriter to use.
4589 Since they can perform almost any function there isn't one included.
4591 For each requested URL, the rewriter will receive on line with the format
4593 [channel-ID <SP>] URL [<SP> extras]<NL>
4595 See url_rewrite_extras on how to send "extras" with optional values to
4597 After processing the request the helper must reply using the following format:
4599 [channel-ID <SP>] result [<SP> kv-pairs]
4601 The result code can be:
4603 OK status=30N url="..."
4604 Redirect the URL to the one supplied in 'url='.
4605 'status=' is optional and contains the status code to send
4606 the client in Squids HTTP response. It must be one of the
4607 HTTP redirect status codes: 301, 302, 303, 307, 308.
4608 When no status is given Squid will use 302.
4610 OK rewrite-url="..."
4611 Rewrite the URL to the one supplied in 'rewrite-url='.
4612 The new URL is fetched directly by Squid and returned to
4613 the client as the response to its request.
4616 When neither of url= and rewrite-url= are sent Squid does
4620 Do not change the URL.
4623 An internal error occurred in the helper, preventing
4624 a result being identified. The 'message=' key name is
4625 reserved for delivering a log message.
4628 In addition to the above kv-pairs Squid also understands the following
4629 optional kv-pairs received from URL rewriters:
4631 Associates a TAG with the client TCP connection.
4632 The TAG is treated as a regular annotation but persists across
4633 future requests on the client connection rather than just the
4634 current request. A helper may update the TAG during subsequent
4635 requests be returning a new kv-pair.
4637 When using the concurrency= option the protocol is changed by
4638 introducing a query channel tag in front of the request/response.
4639 The query channel tag is a number between 0 and concurrency-1.
4640 This value must be echoed back unchanged to Squid as the first part
4641 of the response relating to its request.
4643 WARNING: URL re-writing ability should be avoided whenever possible.
4644 Use the URL redirect form of response instead.
4646 Re-write creates a difference in the state held by the client
4647 and server. Possibly causing confusion when the server response
4648 contains snippets of its view state. Embeded URLs, response
4649 and content Location headers, etc. are not re-written by this
4652 By default, a URL rewriter is not used.
4655 NAME: url_rewrite_children redirect_children
4656 TYPE: HelperChildConfig
4657 DEFAULT: 20 startup=0 idle=1 concurrency=0
4658 LOC: Config.redirectChildren
4660 The maximum number of redirector processes to spawn. If you limit
4661 it too few Squid will have to wait for them to process a backlog of
4662 URLs, slowing it down. If you allow too many they will use RAM
4663 and other system resources noticably.
4665 The startup= and idle= options allow some measure of skew in your
4670 Sets a minimum of how many processes are to be spawned when Squid
4671 starts or reconfigures. When set to zero the first request will
4672 cause spawning of the first child process to handle it.
4674 Starting too few will cause an initial slowdown in traffic as Squid
4675 attempts to simultaneously spawn enough processes to cope.
4679 Sets a minimum of how many processes Squid is to try and keep available
4680 at all times. When traffic begins to rise above what the existing
4681 processes can handle this many more will be spawned up to the maximum
4682 configured. A minimum setting of 1 is required.
4686 The number of requests each redirector helper can handle in
4687 parallel. Defaults to 0 which indicates the redirector
4688 is a old-style single threaded redirector.
4690 When this directive is set to a value >= 1 then the protocol
4691 used to communicate with the helper is modified to include
4692 an ID in front of the request/response. The ID from the request
4693 must be echoed back with the response to that request.
4696 NAME: url_rewrite_host_header redirect_rewrites_host_header
4699 LOC: Config.onoff.redir_rewrites_host
4701 To preserve same-origin security policies in browsers and
4702 prevent Host: header forgery by redirectors Squid rewrites
4703 any Host: header in redirected requests.
4705 If you are running an accelerator this may not be a wanted
4706 effect of a redirector. This directive enables you disable
4707 Host: alteration in reverse-proxy traffic.
4709 WARNING: Entries are cached on the result of the URL rewriting
4710 process, so be careful if you have domain-virtual hosts.
4712 WARNING: Squid and other software verifies the URL and Host
4713 are matching, so be careful not to relay through other proxies
4714 or inspecting firewalls with this disabled.
4717 NAME: url_rewrite_access redirector_access
4720 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
4721 LOC: Config.accessList.redirector
4723 If defined, this access list specifies which requests are
4724 sent to the redirector processes.
4726 This clause supports both fast and slow acl types.
4727 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4730 NAME: url_rewrite_bypass redirector_bypass
4732 LOC: Config.onoff.redirector_bypass
4735 When this is 'on', a request will not go through the
4736 redirector if all the helpers are busy. If this is 'off'
4737 and the redirector queue grows too large, Squid will exit
4738 with a FATAL error and ask you to increase the number of
4739 redirectors. You should only enable this if the redirectors
4740 are not critical to your caching system. If you use
4741 redirectors for access control, and you enable this option,
4742 users may have access to pages they should not
4743 be allowed to request.
4746 NAME: url_rewrite_extras
4747 TYPE: TokenOrQuotedString
4748 LOC: Config.redirector_extras
4749 DEFAULT: "%>a/%>A %un %>rm myip=%la myport=%lp"
4751 Specifies a string to be append to request line format for the
4752 rewriter helper. "Quoted" format values may contain spaces and
4753 logformat %macros. In theory, any logformat %macro can be used.
4754 In practice, a %macro expands as a dash (-) if the helper request is
4755 sent before the required macro information is available to Squid.
4759 OPTIONS FOR STORE ID
4760 -----------------------------------------------------------------------------
4763 NAME: store_id_program storeurl_rewrite_program
4765 LOC: Config.Program.store_id
4768 Specify the location of the executable StoreID helper to use.
4769 Since they can perform almost any function there isn't one included.
4771 For each requested URL, the helper will receive one line with the format
4773 [channel-ID <SP>] URL [<SP> extras]<NL>
4776 After processing the request the helper must reply using the following format:
4778 [channel-ID <SP>] result [<SP> kv-pairs]
4780 The result code can be:
4783 Use the StoreID supplied in 'store-id='.
4786 The default is to use HTTP request URL as the store ID.
4789 An internal error occured in the helper, preventing
4790 a result being identified.
4792 In addition to the above kv-pairs Squid also understands the following
4793 optional kv-pairs received from URL rewriters:
4795 Associates a TAG with the client TCP connection.
4796 Please see url_rewrite_program related documentation for this
4799 Helper programs should be prepared to receive and possibly ignore
4800 additional whitespace-separated tokens on each input line.
4802 When using the concurrency= option the protocol is changed by
4803 introducing a query channel tag in front of the request/response.
4804 The query channel tag is a number between 0 and concurrency-1.
4805 This value must be echoed back unchanged to Squid as the first part
4806 of the response relating to its request.
4808 NOTE: when using StoreID refresh_pattern will apply to the StoreID
4809 returned from the helper and not the URL.
4811 WARNING: Wrong StoreID value returned by a careless helper may result
4812 in the wrong cached response returned to the user.
4814 By default, a StoreID helper is not used.
4817 NAME: store_id_extras
4818 TYPE: TokenOrQuotedString
4819 LOC: Config.storeId_extras
4820 DEFAULT: "%>a/%>A %un %>rm myip=%la myport=%lp"
4822 Specifies a string to be append to request line format for the
4823 StoreId helper. "Quoted" format values may contain spaces and
4824 logformat %macros. In theory, any logformat %macro can be used.
4825 In practice, a %macro expands as a dash (-) if the helper request is
4826 sent before the required macro information is available to Squid.
4829 NAME: store_id_children storeurl_rewrite_children
4830 TYPE: HelperChildConfig
4831 DEFAULT: 20 startup=0 idle=1 concurrency=0
4832 LOC: Config.storeIdChildren
4834 The maximum number of StoreID helper processes to spawn. If you limit
4835 it too few Squid will have to wait for them to process a backlog of
4836 requests, slowing it down. If you allow too many they will use RAM
4837 and other system resources noticably.
4839 The startup= and idle= options allow some measure of skew in your
4844 Sets a minimum of how many processes are to be spawned when Squid
4845 starts or reconfigures. When set to zero the first request will
4846 cause spawning of the first child process to handle it.
4848 Starting too few will cause an initial slowdown in traffic as Squid
4849 attempts to simultaneously spawn enough processes to cope.
4853 Sets a minimum of how many processes Squid is to try and keep available
4854 at all times. When traffic begins to rise above what the existing
4855 processes can handle this many more will be spawned up to the maximum
4856 configured. A minimum setting of 1 is required.
4860 The number of requests each storeID helper can handle in
4861 parallel. Defaults to 0 which indicates the helper
4862 is a old-style single threaded program.
4864 When this directive is set to a value >= 1 then the protocol
4865 used to communicate with the helper is modified to include
4866 an ID in front of the request/response. The ID from the request
4867 must be echoed back with the response to that request.
4870 NAME: store_id_access storeurl_rewrite_access
4873 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
4874 LOC: Config.accessList.store_id
4876 If defined, this access list specifies which requests are
4877 sent to the StoreID processes. By default all requests
4880 This clause supports both fast and slow acl types.
4881 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4884 NAME: store_id_bypass storeurl_rewrite_bypass
4886 LOC: Config.onoff.store_id_bypass
4889 When this is 'on', a request will not go through the
4890 helper if all helpers are busy. If this is 'off'
4891 and the helper queue grows too large, Squid will exit
4892 with a FATAL error and ask you to increase the number of
4893 helpers. You should only enable this if the helperss
4894 are not critical to your caching system. If you use
4895 helpers for critical caching components, and you enable this
4896 option, users may not get objects from cache.
4900 OPTIONS FOR TUNING THE CACHE
4901 -----------------------------------------------------------------------------
4904 NAME: cache no_cache
4907 DEFAULT_DOC: By default, this directive is unused and has no effect.
4908 LOC: Config.accessList.noCache
4910 Requests denied by this directive will not be served from the cache
4911 and their responses will not be stored in the cache. This directive
4912 has no effect on other transactions and on already cached responses.
4914 This clause supports both fast and slow acl types.
4915 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4917 This and the two other similar caching directives listed below are
4918 checked at different transaction processing stages, have different
4919 access to response information, affect different cache operations,
4920 and differ in slow ACLs support:
4922 * cache: Checked before Squid makes a hit/miss determination.
4923 No access to reply information!
4924 Denies both serving a hit and storing a miss.
4925 Supports both fast and slow ACLs.
4926 * send_hit: Checked after a hit was detected.
4927 Has access to reply (hit) information.
4928 Denies serving a hit only.
4929 Supports fast ACLs only.
4930 * store_miss: Checked before storing a cachable miss.
4931 Has access to reply (miss) information.
4932 Denies storing a miss only.
4933 Supports fast ACLs only.
4935 If you are not sure which of the three directives to use, apply the
4936 following decision logic:
4938 * If your ACL(s) are of slow type _and_ need response info, redesign.
4939 Squid does not support that particular combination at this time.
4941 * If your directive ACL(s) are of slow type, use "cache"; and/or
4942 * if your directive ACL(s) need no response info, use "cache".
4944 * If you do not want the response cached, use store_miss; and/or
4945 * if you do not want a hit on a cached response, use send_hit.
4951 DEFAULT_DOC: By default, this directive is unused and has no effect.
4952 LOC: Config.accessList.sendHit
4954 Responses denied by this directive will not be served from the cache
4955 (but may still be cached, see store_miss). This directive has no
4956 effect on the responses it allows and on the cached objects.
4958 Please see the "cache" directive for a summary of differences among
4959 store_miss, send_hit, and cache directives.
4961 Unlike the "cache" directive, send_hit only supports fast acl
4962 types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4966 # apply custom Store ID mapping to some URLs
4967 acl MapMe dstdomain .c.example.com
4968 store_id_program ...
4969 store_id_access allow MapMe
4971 # but prevent caching of special responses
4972 # such as 302 redirects that cause StoreID loops
4973 acl Ordinary http_status 200-299
4974 store_miss deny MapMe !Ordinary
4976 # and do not serve any previously stored special responses
4977 # from the cache (in case they were already cached before
4978 # the above store_miss rule was in effect).
4979 send_hit deny MapMe !Ordinary
4985 DEFAULT_DOC: By default, this directive is unused and has no effect.
4986 LOC: Config.accessList.storeMiss
4988 Responses denied by this directive will not be cached (but may still
4989 be served from the cache, see send_hit). This directive has no
4990 effect on the responses it allows and on the already cached responses.
4992 Please see the "cache" directive for a summary of differences among
4993 store_miss, send_hit, and cache directives. See the
4994 send_hit directive for a usage example.
4996 Unlike the "cache" directive, store_miss only supports fast acl
4997 types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5003 LOC: Config.maxStale
5006 This option puts an upper limit on how stale content Squid
5007 will serve from the cache if cache validation fails.
5008 Can be overriden by the refresh_pattern max-stale option.
5011 NAME: refresh_pattern
5012 TYPE: refreshpattern
5016 usage: refresh_pattern [-i] regex min percent max [options]
5018 By default, regular expressions are CASE-SENSITIVE. To make
5019 them case-insensitive, use the -i option.
5021 'Min' is the time (in minutes) an object without an explicit
5022 expiry time should be considered fresh. The recommended
5023 value is 0, any higher values may cause dynamic applications
5024 to be erroneously cached unless the application designer
5025 has taken the appropriate actions.
5027 'Percent' is a percentage of the objects age (time since last
5028 modification age) an object without explicit expiry time
5029 will be considered fresh.
5031 'Max' is an upper limit on how long objects without an explicit
5032 expiry time will be considered fresh.
5034 options: override-expire
5039 ignore-must-revalidate
5046 override-expire enforces min age even if the server
5047 sent an explicit expiry time (e.g., with the
5048 Expires: header or Cache-Control: max-age). Doing this
5049 VIOLATES the HTTP standard. Enabling this feature
5050 could make you liable for problems which it causes.
5052 Note: override-expire does not enforce staleness - it only extends
5053 freshness / min. If the server returns a Expires time which
5054 is longer than your max time, Squid will still consider
5055 the object fresh for that period of time.
5057 override-lastmod enforces min age even on objects
5058 that were modified recently.
5060 reload-into-ims changes a client no-cache or ``reload''
5061 request for a cached entry into a conditional request using
5062 If-Modified-Since and/or If-None-Match headers, provided the
5063 cached entry has a Last-Modified and/or a strong ETag header.
5064 Doing this VIOLATES the HTTP standard. Enabling this feature
5065 could make you liable for problems which it causes.
5067 ignore-reload ignores a client no-cache or ``reload''
5068 header. Doing this VIOLATES the HTTP standard. Enabling
5069 this feature could make you liable for problems which
5072 ignore-no-store ignores any ``Cache-control: no-store''
5073 headers received from a server. Doing this VIOLATES
5074 the HTTP standard. Enabling this feature could make you
5075 liable for problems which it causes.
5077 ignore-must-revalidate ignores any ``Cache-Control: must-revalidate``
5078 headers received from a server. Doing this VIOLATES
5079 the HTTP standard. Enabling this feature could make you
5080 liable for problems which it causes.
5082 ignore-private ignores any ``Cache-control: private''
5083 headers received from a server. Doing this VIOLATES
5084 the HTTP standard. Enabling this feature could make you
5085 liable for problems which it causes.
5087 ignore-auth caches responses to requests with authorization,
5088 as if the originserver had sent ``Cache-control: public''
5089 in the response header. Doing this VIOLATES the HTTP standard.
5090 Enabling this feature could make you liable for problems which
5093 refresh-ims causes squid to contact the origin server
5094 when a client issues an If-Modified-Since request. This
5095 ensures that the client will receive an updated version
5096 if one is available.
5098 store-stale stores responses even if they don't have explicit
5099 freshness or a validator (i.e., Last-Modified or an ETag)
5100 present, or if they're already stale. By default, Squid will
5101 not cache such responses because they usually can't be
5102 reused. Note that such responses will be stale by default.
5104 max-stale=NN provide a maximum staleness factor. Squid won't
5105 serve objects more stale than this even if it failed to
5106 validate the object. Default: use the max_stale global limit.
5108 Basically a cached object is:
5110 FRESH if expires < now, else STALE
5112 FRESH if lm-factor < percent, else STALE
5116 The refresh_pattern lines are checked in the order listed here.
5117 The first entry which matches is used. If none of the entries
5118 match the default will be used.
5120 Note, you must uncomment all the default lines if you want
5121 to change one. The default setting is only active if none is
5127 # Add any of your own refresh_pattern entries above these.
5129 refresh_pattern ^ftp: 1440 20% 10080
5130 refresh_pattern ^gopher: 1440 0% 1440
5131 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0
5132 refresh_pattern . 0 20% 4320
5136 NAME: quick_abort_min
5140 LOC: Config.quickAbort.min
5143 NAME: quick_abort_max
5147 LOC: Config.quickAbort.max
5150 NAME: quick_abort_pct
5154 LOC: Config.quickAbort.pct
5156 The cache by default continues downloading aborted requests
5157 which are almost completed (less than 16 KB remaining). This
5158 may be undesirable on slow (e.g. SLIP) links and/or very busy
5159 caches. Impatient users may tie up file descriptors and
5160 bandwidth by repeatedly requesting and immediately aborting
5163 When the user aborts a request, Squid will check the
5164 quick_abort values to the amount of data transferred until
5167 If the transfer has less than 'quick_abort_min' KB remaining,
5168 it will finish the retrieval.
5170 If the transfer has more than 'quick_abort_max' KB remaining,
5171 it will abort the retrieval.
5173 If more than 'quick_abort_pct' of the transfer has completed,
5174 it will finish the retrieval.
5176 If you do not want any retrieval to continue after the client
5177 has aborted, set both 'quick_abort_min' and 'quick_abort_max'
5180 If you want retrievals to always continue if they are being
5181 cached set 'quick_abort_min' to '-1 KB'.
5184 NAME: read_ahead_gap
5185 COMMENT: buffer-size
5187 LOC: Config.readAheadGap
5190 The amount of data the cache will buffer ahead of what has been
5191 sent to the client when retrieving an object from another server.
5195 IFDEF: USE_HTTP_VIOLATIONS
5198 LOC: Config.negativeTtl
5201 Set the Default Time-to-Live (TTL) for failed requests.
5202 Certain types of failures (such as "connection refused" and
5203 "404 Not Found") are able to be negatively-cached for a short time.
5204 Modern web servers should provide Expires: header, however if they
5205 do not this can provide a minimum TTL.
5206 The default is not to cache errors with unknown expiry details.
5208 Note that this is different from negative caching of DNS lookups.
5210 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5211 this feature could make you liable for problems which it
5215 NAME: positive_dns_ttl
5218 LOC: Config.positiveDnsTtl
5221 Upper limit on how long Squid will cache positive DNS responses.
5222 Default is 6 hours (360 minutes). This directive must be set
5223 larger than negative_dns_ttl.
5226 NAME: negative_dns_ttl
5229 LOC: Config.negativeDnsTtl
5232 Time-to-Live (TTL) for negative caching of failed DNS lookups.
5233 This also sets the lower cache limit on positive lookups.
5234 Minimum value is 1 second, and it is not recommendable to go
5235 much below 10 seconds.
5238 NAME: range_offset_limit
5239 COMMENT: size [acl acl...]
5241 LOC: Config.rangeOffsetLimit
5244 usage: (size) [units] [[!]aclname]
5246 Sets an upper limit on how far (number of bytes) into the file
5247 a Range request may be to cause Squid to prefetch the whole file.
5248 If beyond this limit, Squid forwards the Range request as it is and
5249 the result is NOT cached.
5251 This is to stop a far ahead range request (lets say start at 17MB)
5252 from making Squid fetch the whole object up to that point before
5253 sending anything to the client.
5255 Multiple range_offset_limit lines may be specified, and they will
5256 be searched from top to bottom on each request until a match is found.
5257 The first match found will be used. If no line matches a request, the
5258 default limit of 0 bytes will be used.
5260 'size' is the limit specified as a number of units.
5262 'units' specifies whether to use bytes, KB, MB, etc.
5263 If no units are specified bytes are assumed.
5265 A size of 0 causes Squid to never fetch more than the
5266 client requested. (default)
5268 A size of 'none' causes Squid to always fetch the object from the
5269 beginning so it may cache the result. (2.0 style)
5271 'aclname' is the name of a defined ACL.
5273 NP: Using 'none' as the byte value here will override any quick_abort settings
5274 that may otherwise apply to the range request. The range request will
5275 be fully fetched from start to finish regardless of the client
5276 actions. This affects bandwidth usage.
5279 NAME: minimum_expiry_time
5282 LOC: Config.minimum_expiry_time
5285 The minimum caching time according to (Expires - Date)
5286 headers Squid honors if the object can't be revalidated.
5287 The default is 60 seconds.
5289 In reverse proxy environments it might be desirable to honor
5290 shorter object lifetimes. It is most likely better to make
5291 your server return a meaningful Last-Modified header however.
5293 In ESI environments where page fragments often have short
5294 lifetimes, this will often be best set to 0.
5297 NAME: store_avg_object_size
5301 LOC: Config.Store.avgObjectSize
5303 Average object size, used to estimate number of objects your
5304 cache can hold. The default is 13 KB.
5306 This is used to pre-seed the cache index memory allocation to
5307 reduce expensive reallocate operations while handling clients
5308 traffic. Too-large values may result in memory allocation during
5309 peak traffic, too-small values will result in wasted memory.
5311 Check the cache manager 'info' report metrics for the real
5312 object sizes seen by your Squid before tuning this.
5315 NAME: store_objects_per_bucket
5318 LOC: Config.Store.objectsPerBucket
5320 Target number of objects per bucket in the store hash table.
5321 Lowering this value increases the total number of buckets and
5322 also the storage maintenance rate. The default is 20.
5327 -----------------------------------------------------------------------------
5330 NAME: request_header_max_size
5334 LOC: Config.maxRequestHeaderSize
5336 This specifies the maximum size for HTTP headers in a request.
5337 Request headers are usually relatively small (about 512 bytes).
5338 Placing a limit on the request header size will catch certain
5339 bugs (for example with persistent connections) and possibly
5340 buffer-overflow or denial-of-service attacks.
5343 NAME: reply_header_max_size
5347 LOC: Config.maxReplyHeaderSize
5349 This specifies the maximum size for HTTP headers in a reply.
5350 Reply headers are usually relatively small (about 512 bytes).
5351 Placing a limit on the reply header size will catch certain
5352 bugs (for example with persistent connections) and possibly
5353 buffer-overflow or denial-of-service attacks.
5356 NAME: request_body_max_size
5360 DEFAULT_DOC: No limit.
5361 LOC: Config.maxRequestBodySize
5363 This specifies the maximum size for an HTTP request body.
5364 In other words, the maximum size of a PUT/POST request.
5365 A user who attempts to send a request with a body larger
5366 than this limit receives an "Invalid Request" error message.
5367 If you set this parameter to a zero (the default), there will
5368 be no limit imposed.
5370 See also client_request_buffer_max_size for an alternative
5371 limitation on client uploads which can be configured.
5374 NAME: client_request_buffer_max_size
5378 LOC: Config.maxRequestBufferSize
5380 This specifies the maximum buffer size of a client request.
5381 It prevents squid eating too much memory when somebody uploads
5385 NAME: chunked_request_body_max_size
5389 LOC: Config.maxChunkedRequestBodySize
5391 A broken or confused HTTP/1.1 client may send a chunked HTTP
5392 request to Squid. Squid does not have full support for that
5393 feature yet. To cope with such requests, Squid buffers the
5394 entire request and then dechunks request body to create a
5395 plain HTTP/1.0 request with a known content length. The plain
5396 request is then used by the rest of Squid code as usual.
5398 The option value specifies the maximum size of the buffer used
5399 to hold the request before the conversion. If the chunked
5400 request size exceeds the specified limit, the conversion
5401 fails, and the client receives an "unsupported request" error,
5402 as if dechunking was disabled.
5404 Dechunking is enabled by default. To disable conversion of
5405 chunked requests, set the maximum to zero.
5407 Request dechunking feature and this option in particular are a
5408 temporary hack. When chunking requests and responses are fully
5409 supported, there will be no need to buffer a chunked request.
5413 IFDEF: USE_HTTP_VIOLATIONS
5416 DEFAULT_DOC: Obey RFC 2616.
5417 LOC: Config.accessList.brokenPosts
5419 A list of ACL elements which, if matched, causes Squid to send
5420 an extra CRLF pair after the body of a PUT/POST request.
5422 Some HTTP servers has broken implementations of PUT/POST,
5423 and rely on an extra CRLF pair sent by some WWW clients.
5425 Quote from RFC2616 section 4.1 on this matter:
5427 Note: certain buggy HTTP/1.0 client implementations generate an
5428 extra CRLF's after a POST request. To restate what is explicitly
5429 forbidden by the BNF, an HTTP/1.1 client must not preface or follow
5430 a request with an extra CRLF.
5432 This clause only supports fast acl types.
5433 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5436 acl buggy_server url_regex ^http://....
5437 broken_posts allow buggy_server
5440 NAME: adaptation_uses_indirect_client icap_uses_indirect_client
5443 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_ADAPTATION
5445 LOC: Adaptation::Config::use_indirect_client
5447 Controls whether the indirect client IP address (instead of the direct
5448 client IP address) is passed to adaptation services.
5450 See also: follow_x_forwarded_for adaptation_send_client_ip
5454 IFDEF: USE_HTTP_VIOLATIONS
5458 LOC: Config.onoff.via
5460 If set (default), Squid will include a Via header in requests and
5461 replies as required by RFC2616.
5467 LOC: Config.onoff.ie_refresh
5470 Microsoft Internet Explorer up until version 5.5 Service
5471 Pack 1 has an issue with transparent proxies, wherein it
5472 is impossible to force a refresh. Turning this on provides
5473 a partial fix to the problem, by causing all IMS-REFRESH
5474 requests from older IE versions to check the origin server
5475 for fresh content. This reduces hit ratio by some amount
5476 (~10% in my experience), but allows users to actually get
5477 fresh content when they want it. Note because Squid
5478 cannot tell if the user is using 5.5 or 5.5SP1, the behavior
5479 of 5.5 is unchanged from old versions of Squid (i.e. a
5480 forced refresh is impossible). Newer versions of IE will,
5481 hopefully, continue to have the new behavior and will be
5482 handled based on that assumption. This option defaults to
5483 the old Squid behavior, which is better for hit ratios but
5484 worse for clients using IE, if they need to be able to
5485 force fresh content.
5488 NAME: vary_ignore_expire
5491 LOC: Config.onoff.vary_ignore_expire
5494 Many HTTP servers supporting Vary gives such objects
5495 immediate expiry time with no cache-control header
5496 when requested by a HTTP/1.0 client. This option
5497 enables Squid to ignore such expiry times until
5498 HTTP/1.1 is fully implemented.
5500 WARNING: If turned on this may eventually cause some
5501 varying objects not intended for caching to get cached.
5504 NAME: request_entities
5506 LOC: Config.onoff.request_entities
5509 Squid defaults to deny GET and HEAD requests with request entities,
5510 as the meaning of such requests are undefined in the HTTP standard
5511 even if not explicitly forbidden.
5513 Set this directive to on if you have clients which insists
5514 on sending request entities in GET or HEAD requests. But be warned
5515 that there is server software (both proxies and web servers) which
5516 can fail to properly process this kind of request which may make you
5517 vulnerable to cache pollution attacks if enabled.
5520 NAME: request_header_access
5521 IFDEF: USE_HTTP_VIOLATIONS
5522 TYPE: http_header_access
5523 LOC: Config.request_header_access
5525 DEFAULT_DOC: No limits.
5527 Usage: request_header_access header_name allow|deny [!]aclname ...
5529 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5530 this feature could make you liable for problems which it
5533 This option replaces the old 'anonymize_headers' and the
5534 older 'http_anonymizer' option with something that is much
5535 more configurable. A list of ACLs for each header name allows
5536 removal of specific header fields under specific conditions.
5538 This option only applies to outgoing HTTP request headers (i.e.,
5539 headers sent by Squid to the next HTTP hop such as a cache peer
5540 or an origin server). The option has no effect during cache hit
5541 detection. The equivalent adaptation vectoring point in ICAP
5542 terminology is post-cache REQMOD.
5544 The option is applied to individual outgoing request header
5545 fields. For each request header field F, Squid uses the first
5546 qualifying sets of request_header_access rules:
5548 1. Rules with header_name equal to F's name.
5549 2. Rules with header_name 'Other', provided F's name is not
5550 on the hard-coded list of commonly used HTTP header names.
5551 3. Rules with header_name 'All'.
5553 Within that qualifying rule set, rule ACLs are checked as usual.
5554 If ACLs of an "allow" rule match, the header field is allowed to
5555 go through as is. If ACLs of a "deny" rule match, the header is
5556 removed and request_header_replace is then checked to identify
5557 if the removed header has a replacement. If no rules within the
5558 set have matching ACLs, the header field is left as is.
5560 For example, to achieve the same behavior as the old
5561 'http_anonymizer standard' option, you should use:
5563 request_header_access From deny all
5564 request_header_access Referer deny all
5565 request_header_access User-Agent deny all
5567 Or, to reproduce the old 'http_anonymizer paranoid' feature
5570 request_header_access Authorization allow all
5571 request_header_access Proxy-Authorization allow all
5572 request_header_access Cache-Control allow all
5573 request_header_access Content-Length allow all
5574 request_header_access Content-Type allow all
5575 request_header_access Date allow all
5576 request_header_access Host allow all
5577 request_header_access If-Modified-Since allow all
5578 request_header_access Pragma allow all
5579 request_header_access Accept allow all
5580 request_header_access Accept-Charset allow all
5581 request_header_access Accept-Encoding allow all
5582 request_header_access Accept-Language allow all
5583 request_header_access Connection allow all
5584 request_header_access All deny all
5586 HTTP reply headers are controlled with the reply_header_access directive.
5588 By default, all headers are allowed (no anonymizing is performed).
5591 NAME: reply_header_access
5592 IFDEF: USE_HTTP_VIOLATIONS
5593 TYPE: http_header_access
5594 LOC: Config.reply_header_access
5596 DEFAULT_DOC: No limits.
5598 Usage: reply_header_access header_name allow|deny [!]aclname ...
5600 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5601 this feature could make you liable for problems which it
5604 This option only applies to reply headers, i.e., from the
5605 server to the client.
5607 This is the same as request_header_access, but in the other
5608 direction. Please see request_header_access for detailed
5611 For example, to achieve the same behavior as the old
5612 'http_anonymizer standard' option, you should use:
5614 reply_header_access Server deny all
5615 reply_header_access WWW-Authenticate deny all
5616 reply_header_access Link deny all
5618 Or, to reproduce the old 'http_anonymizer paranoid' feature
5621 reply_header_access Allow allow all
5622 reply_header_access WWW-Authenticate allow all
5623 reply_header_access Proxy-Authenticate allow all
5624 reply_header_access Cache-Control allow all
5625 reply_header_access Content-Encoding allow all
5626 reply_header_access Content-Length allow all
5627 reply_header_access Content-Type allow all
5628 reply_header_access Date allow all
5629 reply_header_access Expires allow all
5630 reply_header_access Last-Modified allow all
5631 reply_header_access Location allow all
5632 reply_header_access Pragma allow all
5633 reply_header_access Content-Language allow all
5634 reply_header_access Retry-After allow all
5635 reply_header_access Title allow all
5636 reply_header_access Content-Disposition allow all
5637 reply_header_access Connection allow all
5638 reply_header_access All deny all
5640 HTTP request headers are controlled with the request_header_access directive.
5642 By default, all headers are allowed (no anonymizing is
5646 NAME: request_header_replace header_replace
5647 IFDEF: USE_HTTP_VIOLATIONS
5648 TYPE: http_header_replace
5649 LOC: Config.request_header_access
5652 Usage: request_header_replace header_name message
5653 Example: request_header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
5655 This option allows you to change the contents of headers
5656 denied with request_header_access above, by replacing them
5657 with some fixed string.
5659 This only applies to request headers, not reply headers.
5661 By default, headers are removed if denied.
5664 NAME: reply_header_replace
5665 IFDEF: USE_HTTP_VIOLATIONS
5666 TYPE: http_header_replace
5667 LOC: Config.reply_header_access
5670 Usage: reply_header_replace header_name message
5671 Example: reply_header_replace Server Foo/1.0
5673 This option allows you to change the contents of headers
5674 denied with reply_header_access above, by replacing them
5675 with some fixed string.
5677 This only applies to reply headers, not request headers.
5679 By default, headers are removed if denied.
5682 NAME: request_header_add
5683 TYPE: HeaderWithAclList
5684 LOC: Config.request_header_add
5687 Usage: request_header_add field-name field-value acl1 [acl2] ...
5688 Example: request_header_add X-Client-CA "CA=%ssl::>cert_issuer" all
5690 This option adds header fields to outgoing HTTP requests (i.e.,
5691 request headers sent by Squid to the next HTTP hop such as a
5692 cache peer or an origin server). The option has no effect during
5693 cache hit detection. The equivalent adaptation vectoring point
5694 in ICAP terminology is post-cache REQMOD.
5696 Field-name is a token specifying an HTTP header name. If a
5697 standard HTTP header name is used, Squid does not check whether
5698 the new header conflicts with any existing headers or violates
5699 HTTP rules. If the request to be modified already contains a
5700 field with the same name, the old field is preserved but the
5701 header field values are not merged.
5703 Field-value is either a token or a quoted string. If quoted
5704 string format is used, then the surrounding quotes are removed
5705 while escape sequences and %macros are processed.
5707 In theory, all of the logformat codes can be used as %macros.
5708 However, unlike logging (which happens at the very end of
5709 transaction lifetime), the transaction may not yet have enough
5710 information to expand a macro when the new header value is needed.
5711 And some information may already be available to Squid but not yet
5712 committed where the macro expansion code can access it (report
5713 such instances!). The macro will be expanded into a single dash
5714 ('-') in such cases. Not all macros have been tested.
5716 One or more Squid ACLs may be specified to restrict header
5717 injection to matching requests. As always in squid.conf, all
5718 ACLs in an option ACL list must be satisfied for the insertion
5719 to happen. The request_header_add option supports fast ACLs
5728 This option used to log custom information about the master
5729 transaction. For example, an admin may configure Squid to log
5730 which "user group" the transaction belongs to, where "user group"
5731 will be determined based on a set of ACLs and not [just]
5732 authentication information.
5733 Values of key/value pairs can be logged using %{key}note macros:
5735 note key value acl ...
5736 logformat myFormat ... %{key}note ...
5739 NAME: relaxed_header_parser
5740 COMMENT: on|off|warn
5742 LOC: Config.onoff.relaxed_header_parser
5745 In the default "on" setting Squid accepts certain forms
5746 of non-compliant HTTP messages where it is unambiguous
5747 what the sending application intended even if the message
5748 is not correctly formatted. The messages is then normalized
5749 to the correct form when forwarded by Squid.
5751 If set to "warn" then a warning will be emitted in cache.log
5752 each time such HTTP error is encountered.
5754 If set to "off" then such HTTP errors will cause the request
5755 or response to be rejected.
5758 NAME: collapsed_forwarding
5761 LOC: Config.onoff.collapsed_forwarding
5764 This option controls whether Squid is allowed to merge multiple
5765 potentially cachable requests for the same URI before Squid knows
5766 whether the response is going to be cachable.
5768 This feature is disabled by default: Enabling collapsed forwarding
5769 needlessly delays forwarding requests that look cachable (when they are
5770 collapsed) but then need to be forwarded individually anyway because
5771 they end up being for uncachable content. However, in some cases, such
5772 as accelleration of highly cachable content with periodic or groupped
5773 expiration times, the gains from collapsing [large volumes of
5774 simultenous refresh requests] outweigh losses from such delays.
5779 -----------------------------------------------------------------------------
5782 NAME: forward_timeout
5785 LOC: Config.Timeout.forward
5788 This parameter specifies how long Squid should at most attempt in
5789 finding a forwarding path for the request before giving up.
5792 NAME: connect_timeout
5795 LOC: Config.Timeout.connect
5798 This parameter specifies how long to wait for the TCP connect to
5799 the requested server or peer to complete before Squid should
5800 attempt to find another path where to forward the request.
5803 NAME: peer_connect_timeout
5806 LOC: Config.Timeout.peer_connect
5809 This parameter specifies how long to wait for a pending TCP
5810 connection to a peer cache. The default is 30 seconds. You
5811 may also set different timeout values for individual neighbors
5812 with the 'connect-timeout' option on a 'cache_peer' line.
5818 LOC: Config.Timeout.read
5821 The read_timeout is applied on server-side connections. After
5822 each successful read(), the timeout will be extended by this
5823 amount. If no data is read again after this amount of time,
5824 the request is aborted and logged with ERR_READ_TIMEOUT. The
5825 default is 15 minutes.
5831 LOC: Config.Timeout.write
5834 This timeout is tracked for all connections that have data
5835 available for writing and are waiting for the socket to become
5836 ready. After each successful write, the timeout is extended by
5837 the configured amount. If Squid has data to write but the
5838 connection is not ready for the configured duration, the
5839 transaction associated with the connection is terminated. The
5840 default is 15 minutes.
5843 NAME: request_timeout
5845 LOC: Config.Timeout.request
5848 How long to wait for complete HTTP request headers after initial
5849 connection establishment.
5852 NAME: client_idle_pconn_timeout persistent_request_timeout
5854 LOC: Config.Timeout.clientIdlePconn
5857 How long to wait for the next HTTP request on a persistent
5858 client connection after the previous request completes.
5861 NAME: client_lifetime
5864 LOC: Config.Timeout.lifetime
5867 The maximum amount of time a client (browser) is allowed to
5868 remain connected to the cache process. This protects the Cache
5869 from having a lot of sockets (and hence file descriptors) tied up
5870 in a CLOSE_WAIT state from remote clients that go away without
5871 properly shutting down (either because of a network failure or
5872 because of a poor client implementation). The default is one
5875 NOTE: The default value is intended to be much larger than any
5876 client would ever need to be connected to your cache. You
5877 should probably change client_lifetime only as a last resort.
5878 If you seem to have many client connections tying up
5879 filedescriptors, we recommend first tuning the read_timeout,
5880 request_timeout, persistent_request_timeout and quick_abort values.
5883 NAME: half_closed_clients
5885 LOC: Config.onoff.half_closed_clients
5888 Some clients may shutdown the sending side of their TCP
5889 connections, while leaving their receiving sides open. Sometimes,
5890 Squid can not tell the difference between a half-closed and a
5891 fully-closed TCP connection.
5893 By default, Squid will immediately close client connections when
5894 read(2) returns "no more data to read."
5896 Change this option to 'on' and Squid will keep open connections
5897 until a read(2) or write(2) on the socket returns an error.
5898 This may show some benefits for reverse proxies. But if not
5899 it is recommended to leave OFF.
5902 NAME: server_idle_pconn_timeout pconn_timeout
5904 LOC: Config.Timeout.serverIdlePconn
5907 Timeout for idle persistent connections to servers and other
5914 LOC: Ident::TheConfig.timeout
5917 Maximum time to wait for IDENT lookups to complete.
5919 If this is too high, and you enabled IDENT lookups from untrusted
5920 users, you might be susceptible to denial-of-service by having
5921 many ident requests going at once.
5924 NAME: shutdown_lifetime
5927 LOC: Config.shutdownLifetime
5930 When SIGTERM or SIGHUP is received, the cache is put into
5931 "shutdown pending" mode until all active sockets are closed.
5932 This value is the lifetime to set for all open descriptors
5933 during shutdown mode. Any active clients after this many
5934 seconds will receive a 'timeout' message.
5938 ADMINISTRATIVE PARAMETERS
5939 -----------------------------------------------------------------------------
5945 LOC: Config.adminEmail
5947 Email-address of local cache manager who will receive
5948 mail if the cache dies. The default is "webmaster".
5954 LOC: Config.EmailFrom
5956 From: email-address for mail sent when the cache dies.
5957 The default is to use 'squid@unique_hostname'.
5959 See also: unique_hostname directive.
5965 LOC: Config.EmailProgram
5967 Email program used to send mail if the cache dies.
5968 The default is "mail". The specified program must comply
5969 with the standard Unix mail syntax:
5970 mail-program recipient < mailfile
5972 Optional command line options can be specified.
5975 NAME: cache_effective_user
5977 DEFAULT: @DEFAULT_CACHE_EFFECTIVE_USER@
5978 LOC: Config.effectiveUser
5980 If you start Squid as root, it will change its effective/real
5981 UID/GID to the user specified below. The default is to change
5982 to UID of @DEFAULT_CACHE_EFFECTIVE_USER@.
5983 see also; cache_effective_group
5986 NAME: cache_effective_group
5989 DEFAULT_DOC: Use system group memberships of the cache_effective_user account
5990 LOC: Config.effectiveGroup
5992 Squid sets the GID to the effective user's default group ID
5993 (taken from the password file) and supplementary group list
5994 from the groups membership.
5996 If you want Squid to run with a specific GID regardless of
5997 the group memberships of the effective user then set this
5998 to the group (or GID) you want Squid to run as. When set
5999 all other group privileges of the effective user are ignored
6000 and only this GID is effective. If Squid is not started as
6001 root the user starting Squid MUST be member of the specified
6004 This option is not recommended by the Squid Team.
6005 Our preference is for administrators to configure a secure
6006 user account for squid with UID/GID matching system policies.
6009 NAME: httpd_suppress_version_string
6013 LOC: Config.onoff.httpd_suppress_version_string
6015 Suppress Squid version string info in HTTP headers and HTML error pages.
6018 NAME: visible_hostname
6020 LOC: Config.visibleHostname
6022 DEFAULT_DOC: Automatically detect the system host name
6024 If you want to present a special hostname in error messages, etc,
6025 define this. Otherwise, the return value of gethostname()
6026 will be used. If you have multiple caches in a cluster and
6027 get errors about IP-forwarding you must set them to have individual
6028 names with this setting.
6031 NAME: unique_hostname
6033 LOC: Config.uniqueHostname
6035 DEFAULT_DOC: Copy the value from visible_hostname
6037 If you want to have multiple machines with the same
6038 'visible_hostname' you must give each machine a different
6039 'unique_hostname' so forwarding loops can be detected.
6042 NAME: hostname_aliases
6044 LOC: Config.hostnameAliases
6047 A list of other DNS names your cache has.
6055 Minimum umask which should be enforced while the proxy
6056 is running, in addition to the umask set at startup.
6058 For a traditional octal representation of umasks, start
6063 OPTIONS FOR THE CACHE REGISTRATION SERVICE
6064 -----------------------------------------------------------------------------
6066 This section contains parameters for the (optional) cache
6067 announcement service. This service is provided to help
6068 cache administrators locate one another in order to join or
6069 create cache hierarchies.
6071 An 'announcement' message is sent (via UDP) to the registration
6072 service by Squid. By default, the announcement message is NOT
6073 SENT unless you enable it with 'announce_period' below.
6075 The announcement message includes your hostname, plus the
6076 following information from this configuration file:
6082 All current information is processed regularly and made
6083 available on the Web at http://www.ircache.net/Cache/Tracker/.
6086 NAME: announce_period
6088 LOC: Config.Announce.period
6090 DEFAULT_DOC: Announcement messages disabled.
6092 This is how frequently to send cache announcements.
6094 To enable announcing your cache, just set an announce period.
6097 announce_period 1 day
6102 DEFAULT: tracker.ircache.net
6103 LOC: Config.Announce.host
6105 Set the hostname where announce registration messages will be sent.
6107 See also announce_port and announce_file
6113 LOC: Config.Announce.file
6115 The contents of this file will be included in the announce
6116 registration messages.
6122 LOC: Config.Announce.port
6124 Set the port where announce registration messages will be sent.
6126 See also announce_host and announce_file
6130 HTTPD-ACCELERATOR OPTIONS
6131 -----------------------------------------------------------------------------
6134 NAME: httpd_accel_surrogate_id
6137 DEFAULT_DOC: visible_hostname is used if no specific ID is set.
6138 LOC: Config.Accel.surrogate_id
6140 Surrogates (http://www.esi.org/architecture_spec_1.0.html)
6141 need an identification token to allow control targeting. Because
6142 a farm of surrogates may all perform the same tasks, they may share
6143 an identification token.
6146 NAME: http_accel_surrogate_remote
6150 LOC: Config.onoff.surrogate_is_remote
6152 Remote surrogates (such as those in a CDN) honour the header
6153 "Surrogate-Control: no-store-remote".
6155 Set this to on to have squid behave as a remote surrogate.
6159 IFDEF: USE_SQUID_ESI
6160 COMMENT: libxml2|expat|custom
6162 LOC: ESIParser::Type
6165 ESI markup is not strictly XML compatible. The custom ESI parser
6166 will give higher performance, but cannot handle non ASCII character
6171 DELAY POOL PARAMETERS
6172 -----------------------------------------------------------------------------
6176 TYPE: delay_pool_count
6178 IFDEF: USE_DELAY_POOLS
6181 This represents the number of delay pools to be used. For example,
6182 if you have one class 2 delay pool and one class 3 delays pool, you
6183 have a total of 2 delay pools.
6185 See also delay_parameters, delay_class, delay_access for pool
6186 configuration details.
6190 TYPE: delay_pool_class
6192 IFDEF: USE_DELAY_POOLS
6195 This defines the class of each delay pool. There must be exactly one
6196 delay_class line for each delay pool. For example, to define two
6197 delay pools, one of class 2 and one of class 3, the settings above
6201 delay_pools 4 # 4 delay pools
6202 delay_class 1 2 # pool 1 is a class 2 pool
6203 delay_class 2 3 # pool 2 is a class 3 pool
6204 delay_class 3 4 # pool 3 is a class 4 pool
6205 delay_class 4 5 # pool 4 is a class 5 pool
6207 The delay pool classes are:
6209 class 1 Everything is limited by a single aggregate
6212 class 2 Everything is limited by a single aggregate
6213 bucket as well as an "individual" bucket chosen
6214 from bits 25 through 32 of the IPv4 address.
6216 class 3 Everything is limited by a single aggregate
6217 bucket as well as a "network" bucket chosen
6218 from bits 17 through 24 of the IP address and a
6219 "individual" bucket chosen from bits 17 through
6220 32 of the IPv4 address.
6222 class 4 Everything in a class 3 delay pool, with an
6223 additional limit on a per user basis. This
6224 only takes effect if the username is established
6225 in advance - by forcing authentication in your
6228 class 5 Requests are grouped according their tag (see
6229 external_acl's tag= reply).
6232 Each pool also requires a delay_parameters directive to configure the pool size
6233 and speed limits used whenever the pool is applied to a request. Along with
6234 a set of delay_access directives to determine when it is used.
6236 NOTE: If an IP address is a.b.c.d
6237 -> bits 25 through 32 are "d"
6238 -> bits 17 through 24 are "c"
6239 -> bits 17 through 32 are "c * 256 + d"
6241 NOTE-2: Due to the use of bitmasks in class 2,3,4 pools they only apply to
6242 IPv4 traffic. Class 1 and 5 pools may be used with IPv6 traffic.
6244 This clause only supports fast acl types.
6245 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6247 See also delay_parameters and delay_access.
6251 TYPE: delay_pool_access
6253 DEFAULT_DOC: Deny using the pool, unless allow rules exist in squid.conf for the pool.
6254 IFDEF: USE_DELAY_POOLS
6257 This is used to determine which delay pool a request falls into.
6259 delay_access is sorted per pool and the matching starts with pool 1,
6260 then pool 2, ..., and finally pool N. The first delay pool where the
6261 request is allowed is selected for the request. If it does not allow
6262 the request to any pool then the request is not delayed (default).
6264 For example, if you want some_big_clients in delay
6265 pool 1 and lotsa_little_clients in delay pool 2:
6267 delay_access 1 allow some_big_clients
6268 delay_access 1 deny all
6269 delay_access 2 allow lotsa_little_clients
6270 delay_access 2 deny all
6271 delay_access 3 allow authenticated_clients
6273 See also delay_parameters and delay_class.
6277 NAME: delay_parameters
6278 TYPE: delay_pool_rates
6280 IFDEF: USE_DELAY_POOLS
6283 This defines the parameters for a delay pool. Each delay pool has
6284 a number of "buckets" associated with it, as explained in the
6285 description of delay_class.
6287 For a class 1 delay pool, the syntax is:
6289 delay_parameters pool aggregate
6291 For a class 2 delay pool:
6293 delay_parameters pool aggregate individual
6295 For a class 3 delay pool:
6297 delay_parameters pool aggregate network individual
6299 For a class 4 delay pool:
6301 delay_parameters pool aggregate network individual user
6303 For a class 5 delay pool:
6305 delay_parameters pool tagrate
6307 The option variables are:
6309 pool a pool number - ie, a number between 1 and the
6310 number specified in delay_pools as used in
6313 aggregate the speed limit parameters for the aggregate bucket
6316 individual the speed limit parameters for the individual
6317 buckets (class 2, 3).
6319 network the speed limit parameters for the network buckets
6322 user the speed limit parameters for the user buckets
6325 tagrate the speed limit parameters for the tag buckets
6328 A pair of delay parameters is written restore/maximum, where restore is
6329 the number of bytes (not bits - modem and network speeds are usually
6330 quoted in bits) per second placed into the bucket, and maximum is the
6331 maximum number of bytes which can be in the bucket at any time.
6333 There must be one delay_parameters line for each delay pool.
6336 For example, if delay pool number 1 is a class 2 delay pool as in the
6337 above example, and is being used to strictly limit each host to 64Kbit/sec
6338 (plus overheads), with no overall limit, the line is:
6340 delay_parameters 1 -1/-1 8000/8000
6342 Note that 8 x 8000 KByte/sec -> 64Kbit/sec.
6344 Note that the figure -1 is used to represent "unlimited".
6347 And, if delay pool number 2 is a class 3 delay pool as in the above
6348 example, and you want to limit it to a total of 256Kbit/sec (strict limit)
6349 with each 8-bit network permitted 64Kbit/sec (strict limit) and each
6350 individual host permitted 4800bit/sec with a bucket maximum size of 64Kbits
6351 to permit a decent web page to be downloaded at a decent speed
6352 (if the network is not being limited due to overuse) but slow down
6353 large downloads more significantly:
6355 delay_parameters 2 32000/32000 8000/8000 600/8000
6357 Note that 8 x 32000 KByte/sec -> 256Kbit/sec.
6358 8 x 8000 KByte/sec -> 64Kbit/sec.
6359 8 x 600 Byte/sec -> 4800bit/sec.
6362 Finally, for a class 4 delay pool as in the example - each user will
6363 be limited to 128Kbits/sec no matter how many workstations they are logged into.:
6365 delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000
6368 See also delay_class and delay_access.
6372 NAME: delay_initial_bucket_level
6373 COMMENT: (percent, 0-100)
6376 IFDEF: USE_DELAY_POOLS
6377 LOC: Config.Delay.initial
6379 The initial bucket percentage is used to determine how much is put
6380 in each bucket when squid starts, is reconfigured, or first notices
6381 a host accessing it (in class 2 and class 3, individual hosts and
6382 networks only have buckets associated with them once they have been
6387 CLIENT DELAY POOL PARAMETERS
6388 -----------------------------------------------------------------------------
6391 NAME: client_delay_pools
6392 TYPE: client_delay_pool_count
6394 IFDEF: USE_DELAY_POOLS
6395 LOC: Config.ClientDelay
6397 This option specifies the number of client delay pools used. It must
6398 preceed other client_delay_* options.
6401 client_delay_pools 2
6403 See also client_delay_parameters and client_delay_access.
6406 NAME: client_delay_initial_bucket_level
6407 COMMENT: (percent, 0-no_limit)
6410 IFDEF: USE_DELAY_POOLS
6411 LOC: Config.ClientDelay.initial
6413 This option determines the initial bucket size as a percentage of
6414 max_bucket_size from client_delay_parameters. Buckets are created
6415 at the time of the "first" connection from the matching IP. Idle
6416 buckets are periodically deleted up.
6418 You can specify more than 100 percent but note that such "oversized"
6419 buckets are not refilled until their size goes down to max_bucket_size
6420 from client_delay_parameters.
6423 client_delay_initial_bucket_level 50
6426 NAME: client_delay_parameters
6427 TYPE: client_delay_pool_rates
6429 IFDEF: USE_DELAY_POOLS
6430 LOC: Config.ClientDelay
6433 This option configures client-side bandwidth limits using the
6436 client_delay_parameters pool speed_limit max_bucket_size
6438 pool is an integer ID used for client_delay_access matching.
6440 speed_limit is bytes added to the bucket per second.
6442 max_bucket_size is the maximum size of a bucket, enforced after any
6443 speed_limit additions.
6445 Please see the delay_parameters option for more information and
6449 client_delay_parameters 1 1024 2048
6450 client_delay_parameters 2 51200 16384
6452 See also client_delay_access.
6456 NAME: client_delay_access
6457 TYPE: client_delay_pool_access
6459 DEFAULT_DOC: Deny use of the pool, unless allow rules exist in squid.conf for the pool.
6460 IFDEF: USE_DELAY_POOLS
6461 LOC: Config.ClientDelay
6463 This option determines the client-side delay pool for the
6466 client_delay_access pool_ID allow|deny acl_name
6468 All client_delay_access options are checked in their pool ID
6469 order, starting with pool 1. The first checked pool with allowed
6470 request is selected for the request. If no ACL matches or there
6471 are no client_delay_access options, the request bandwidth is not
6474 The ACL-selected pool is then used to find the
6475 client_delay_parameters for the request. Client-side pools are
6476 not used to aggregate clients. Clients are always aggregated
6477 based on their source IP addresses (one bucket per source IP).
6479 This clause only supports fast acl types.
6480 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6481 Additionally, only the client TCP connection details are available.
6482 ACLs testing HTTP properties will not work.
6484 Please see delay_access for more examples.
6487 client_delay_access 1 allow low_rate_network
6488 client_delay_access 2 allow vips_network
6491 See also client_delay_parameters and client_delay_pools.
6495 WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS
6496 -----------------------------------------------------------------------------
6501 LOC: Config.Wccp.router
6503 DEFAULT_DOC: WCCP disabled.
6506 Use this option to define your WCCP ``home'' router for
6509 wccp_router supports a single WCCP(v1) router
6511 wccp2_router supports multiple WCCPv2 routers
6513 only one of the two may be used at the same time and defines
6514 which version of WCCP to use.
6518 TYPE: IpAddress_list
6519 LOC: Config.Wccp2.router
6521 DEFAULT_DOC: WCCPv2 disabled.
6524 Use this option to define your WCCP ``home'' router for
6527 wccp_router supports a single WCCP(v1) router
6529 wccp2_router supports multiple WCCPv2 routers
6531 only one of the two may be used at the same time and defines
6532 which version of WCCP to use.
6537 LOC: Config.Wccp.version
6541 This directive is only relevant if you need to set up WCCP(v1)
6542 to some very old and end-of-life Cisco routers. In all other
6543 setups it must be left unset or at the default setting.
6544 It defines an internal version in the WCCP(v1) protocol,
6545 with version 4 being the officially documented protocol.
6547 According to some users, Cisco IOS 11.2 and earlier only
6548 support WCCP version 3. If you're using that or an earlier
6549 version of IOS, you may need to change this value to 3, otherwise
6550 do not specify this parameter.
6553 NAME: wccp2_rebuild_wait
6555 LOC: Config.Wccp2.rebuildwait
6559 If this is enabled Squid will wait for the cache dir rebuild to finish
6560 before sending the first wccp2 HereIAm packet
6563 NAME: wccp2_forwarding_method
6565 LOC: Config.Wccp2.forwarding_method
6569 WCCP2 allows the setting of forwarding methods between the
6570 router/switch and the cache. Valid values are as follows:
6572 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
6573 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
6575 Currently (as of IOS 12.4) cisco routers only support GRE.
6576 Cisco switches only support the L2 redirect assignment method.
6579 NAME: wccp2_return_method
6581 LOC: Config.Wccp2.return_method
6585 WCCP2 allows the setting of return methods between the
6586 router/switch and the cache for packets that the cache
6587 decides not to handle. Valid values are as follows:
6589 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
6590 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
6592 Currently (as of IOS 12.4) cisco routers only support GRE.
6593 Cisco switches only support the L2 redirect assignment.
6595 If the "ip wccp redirect exclude in" command has been
6596 enabled on the cache interface, then it is still safe for
6597 the proxy server to use a l2 redirect method even if this
6598 option is set to GRE.
6601 NAME: wccp2_assignment_method
6603 LOC: Config.Wccp2.assignment_method
6607 WCCP2 allows the setting of methods to assign the WCCP hash
6608 Valid values are as follows:
6610 hash - Hash assignment
6611 mask - Mask assignment
6613 As a general rule, cisco routers support the hash assignment method
6614 and cisco switches support the mask assignment method.
6619 LOC: Config.Wccp2.info
6620 DEFAULT_IF_NONE: standard 0
6621 DEFAULT_DOC: Use the 'web-cache' standard service.
6624 WCCP2 allows for multiple traffic services. There are two
6625 types: "standard" and "dynamic". The standard type defines
6626 one service id - http (id 0). The dynamic service ids can be from
6627 51 to 255 inclusive. In order to use a dynamic service id
6628 one must define the type of traffic to be redirected; this is done
6629 using the wccp2_service_info option.
6631 The "standard" type does not require a wccp2_service_info option,
6632 just specifying the service id will suffice.
6634 MD5 service authentication can be enabled by adding
6635 "password=<password>" to the end of this service declaration.
6639 wccp2_service standard 0 # for the 'web-cache' standard service
6640 wccp2_service dynamic 80 # a dynamic service type which will be
6641 # fleshed out with subsequent options.
6642 wccp2_service standard 0 password=foo
6645 NAME: wccp2_service_info
6646 TYPE: wccp2_service_info
6647 LOC: Config.Wccp2.info
6651 Dynamic WCCPv2 services require further information to define the
6652 traffic you wish to have diverted.
6656 wccp2_service_info <id> protocol=<protocol> flags=<flag>,<flag>..
6657 priority=<priority> ports=<port>,<port>..
6659 The relevant WCCPv2 flags:
6660 + src_ip_hash, dst_ip_hash
6661 + source_port_hash, dst_port_hash
6662 + src_ip_alt_hash, dst_ip_alt_hash
6663 + src_port_alt_hash, dst_port_alt_hash
6666 The port list can be one to eight entries.
6670 wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source
6671 priority=240 ports=80
6673 Note: the service id must have been defined by a previous
6674 'wccp2_service dynamic <id>' entry.
6679 LOC: Config.Wccp2.weight
6683 Each cache server gets assigned a set of the destination
6684 hash proportional to their weight.
6689 LOC: Config.Wccp.address
6691 DEFAULT_DOC: Address selected by the operating system.
6694 Use this option if you require WCCPv2 to use a specific
6697 The default behavior is to not bind to any specific address.
6702 LOC: Config.Wccp2.address
6704 DEFAULT_DOC: Address selected by the operating system.
6707 Use this option if you require WCCP to use a specific
6710 The default behavior is to not bind to any specific address.
6714 PERSISTENT CONNECTION HANDLING
6715 -----------------------------------------------------------------------------
6717 Also see "pconn_timeout" in the TIMEOUTS section
6720 NAME: client_persistent_connections
6722 LOC: Config.onoff.client_pconns
6725 Persistent connection support for clients.
6726 Squid uses persistent connections (when allowed). You can use
6727 this option to disable persistent connections with clients.
6730 NAME: server_persistent_connections
6732 LOC: Config.onoff.server_pconns
6735 Persistent connection support for servers.
6736 Squid uses persistent connections (when allowed). You can use
6737 this option to disable persistent connections with servers.
6740 NAME: persistent_connection_after_error
6742 LOC: Config.onoff.error_pconns
6745 With this directive the use of persistent connections after
6746 HTTP errors can be disabled. Useful if you have clients
6747 who fail to handle errors on persistent connections proper.
6750 NAME: detect_broken_pconn
6752 LOC: Config.onoff.detect_broken_server_pconns
6755 Some servers have been found to incorrectly signal the use
6756 of HTTP/1.0 persistent connections even on replies not
6757 compatible, causing significant delays. This server problem
6758 has mostly been seen on redirects.
6760 By enabling this directive Squid attempts to detect such
6761 broken replies and automatically assume the reply is finished
6762 after 10 seconds timeout.
6766 CACHE DIGEST OPTIONS
6767 -----------------------------------------------------------------------------
6770 NAME: digest_generation
6771 IFDEF: USE_CACHE_DIGESTS
6773 LOC: Config.onoff.digest_generation
6776 This controls whether the server will generate a Cache Digest
6777 of its contents. By default, Cache Digest generation is
6778 enabled if Squid is compiled with --enable-cache-digests defined.
6781 NAME: digest_bits_per_entry
6782 IFDEF: USE_CACHE_DIGESTS
6784 LOC: Config.digest.bits_per_entry
6787 This is the number of bits of the server's Cache Digest which
6788 will be associated with the Digest entry for a given HTTP
6789 Method and URL (public key) combination. The default is 5.
6792 NAME: digest_rebuild_period
6793 IFDEF: USE_CACHE_DIGESTS
6796 LOC: Config.digest.rebuild_period
6799 This is the wait time between Cache Digest rebuilds.
6802 NAME: digest_rewrite_period
6804 IFDEF: USE_CACHE_DIGESTS
6806 LOC: Config.digest.rewrite_period
6809 This is the wait time between Cache Digest writes to
6813 NAME: digest_swapout_chunk_size
6816 IFDEF: USE_CACHE_DIGESTS
6817 LOC: Config.digest.swapout_chunk_size
6820 This is the number of bytes of the Cache Digest to write to
6821 disk at a time. It defaults to 4096 bytes (4KB), the Squid
6825 NAME: digest_rebuild_chunk_percentage
6826 COMMENT: (percent, 0-100)
6827 IFDEF: USE_CACHE_DIGESTS
6829 LOC: Config.digest.rebuild_chunk_percentage
6832 This is the percentage of the Cache Digest to be scanned at a
6833 time. By default it is set to 10% of the Cache Digest.
6838 -----------------------------------------------------------------------------
6843 LOC: Config.Port.snmp
6845 DEFAULT_DOC: SNMP disabled.
6848 The port number where Squid listens for SNMP requests. To enable
6849 SNMP support set this to a suitable port number. Port number
6850 3401 is often used for the Squid SNMP agent. By default it's
6851 set to "0" (disabled)
6859 LOC: Config.accessList.snmp
6861 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
6864 Allowing or denying access to the SNMP port.
6866 All access to the agent is denied by default.
6869 snmp_access allow|deny [!]aclname ...
6871 This clause only supports fast acl types.
6872 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6875 snmp_access allow snmppublic localhost
6876 snmp_access deny all
6879 NAME: snmp_incoming_address
6881 LOC: Config.Addrs.snmp_incoming
6883 DEFAULT_DOC: Accept SNMP packets from all machine interfaces.
6886 Just like 'udp_incoming_address', but for the SNMP port.
6888 snmp_incoming_address is used for the SNMP socket receiving
6889 messages from SNMP agents.
6891 The default snmp_incoming_address is to listen on all
6892 available network interfaces.
6895 NAME: snmp_outgoing_address
6897 LOC: Config.Addrs.snmp_outgoing
6899 DEFAULT_DOC: Use snmp_incoming_address or an address selected by the operating system.
6902 Just like 'udp_outgoing_address', but for the SNMP port.
6904 snmp_outgoing_address is used for SNMP packets returned to SNMP
6907 If snmp_outgoing_address is not set it will use the same socket
6908 as snmp_incoming_address. Only change this if you want to have
6909 SNMP replies sent using another address than where this Squid
6910 listens for SNMP queries.
6912 NOTE, snmp_incoming_address and snmp_outgoing_address can not have
6913 the same value since they both use the same port.
6918 -----------------------------------------------------------------------------
6921 NAME: icp_port udp_port
6924 DEFAULT_DOC: ICP disabled.
6925 LOC: Config.Port.icp
6927 The port number where Squid sends and receives ICP queries to
6928 and from neighbor caches. The standard UDP port for ICP is 3130.
6931 icp_port @DEFAULT_ICP_PORT@
6938 DEFAULT_DOC: HTCP disabled.
6939 LOC: Config.Port.htcp
6941 The port number where Squid sends and receives HTCP queries to
6942 and from neighbor caches. To turn it on you want to set it to
6949 NAME: log_icp_queries
6953 LOC: Config.onoff.log_udp
6955 If set, ICP queries are logged to access.log. You may wish
6956 do disable this if your ICP load is VERY high to speed things
6957 up or to simplify log analysis.
6960 NAME: udp_incoming_address
6962 LOC:Config.Addrs.udp_incoming
6964 DEFAULT_DOC: Accept packets from all machine interfaces.
6966 udp_incoming_address is used for UDP packets received from other
6969 The default behavior is to not bind to any specific address.
6971 Only change this if you want to have all UDP queries received on
6972 a specific interface/address.
6974 NOTE: udp_incoming_address is used by the ICP, HTCP, and DNS
6975 modules. Altering it will affect all of them in the same manner.
6977 see also; udp_outgoing_address
6979 NOTE, udp_incoming_address and udp_outgoing_address can not
6980 have the same value since they both use the same port.
6983 NAME: udp_outgoing_address
6985 LOC: Config.Addrs.udp_outgoing
6987 DEFAULT_DOC: Use udp_incoming_address or an address selected by the operating system.
6989 udp_outgoing_address is used for UDP packets sent out to other
6992 The default behavior is to not bind to any specific address.
6994 Instead it will use the same socket as udp_incoming_address.
6995 Only change this if you want to have UDP queries sent using another
6996 address than where this Squid listens for UDP queries from other
6999 NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS
7000 modules. Altering it will affect all of them in the same manner.
7002 see also; udp_incoming_address
7004 NOTE, udp_incoming_address and udp_outgoing_address can not
7005 have the same value since they both use the same port.
7012 LOC: Config.onoff.icp_hit_stale
7014 If you want to return ICP_HIT for stale cache objects, set this
7015 option to 'on'. If you have sibling relationships with caches
7016 in other administrative domains, this should be 'off'. If you only
7017 have sibling relationships with caches under your control,
7018 it is probably okay to set this to 'on'.
7019 If set to 'on', your siblings should use the option "allow-miss"
7020 on their cache_peer lines for connecting to you.
7023 NAME: minimum_direct_hops
7026 LOC: Config.minDirectHops
7028 If using the ICMP pinging stuff, do direct fetches for sites
7029 which are no more than this many hops away.
7032 NAME: minimum_direct_rtt
7036 LOC: Config.minDirectRtt
7038 If using the ICMP pinging stuff, do direct fetches for sites
7039 which are no more than this many rtt milliseconds away.
7045 LOC: Config.Netdb.low
7047 The low water mark for the ICMP measurement database.
7049 Note: high watermark controlled by netdb_high directive.
7051 These watermarks are counts, not percents. The defaults are
7052 (low) 900 and (high) 1000. When the high water mark is
7053 reached, database entries will be deleted until the low
7060 LOC: Config.Netdb.high
7062 The high water mark for the ICMP measurement database.
7064 Note: low watermark controlled by netdb_low directive.
7066 These watermarks are counts, not percents. The defaults are
7067 (low) 900 and (high) 1000. When the high water mark is
7068 reached, database entries will be deleted until the low
7072 NAME: netdb_ping_period
7074 LOC: Config.Netdb.period
7077 The minimum period for measuring a site. There will be at
7078 least this much delay between successive pings to the same
7079 network. The default is five minutes.
7086 LOC: Config.onoff.query_icmp
7088 If you want to ask your peers to include ICMP data in their ICP
7089 replies, enable this option.
7091 If your peer has configured Squid (during compilation) with
7092 '--enable-icmp' that peer will send ICMP pings to origin server
7093 sites of the URLs it receives. If you enable this option the
7094 ICP replies from that peer will include the ICMP data (if available).
7095 Then, when choosing a parent cache, Squid will choose the parent with
7096 the minimal RTT to the origin server. When this happens, the
7097 hierarchy field of the access.log will be
7098 "CLOSEST_PARENT_MISS". This option is off by default.
7101 NAME: test_reachability
7105 LOC: Config.onoff.test_reachability
7107 When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
7108 instead of ICP_MISS if the target host is NOT in the ICMP
7109 database, or has a zero RTT.
7112 NAME: icp_query_timeout
7115 DEFAULT_DOC: Dynamic detection.
7117 LOC: Config.Timeout.icp_query
7119 Normally Squid will automatically determine an optimal ICP
7120 query timeout value based on the round-trip-time of recent ICP
7121 queries. If you want to override the value determined by
7122 Squid, set this 'icp_query_timeout' to a non-zero value. This
7123 value is specified in MILLISECONDS, so, to use a 2-second
7124 timeout (the old default), you would write:
7126 icp_query_timeout 2000
7129 NAME: maximum_icp_query_timeout
7133 LOC: Config.Timeout.icp_query_max
7135 Normally the ICP query timeout is determined dynamically. But
7136 sometimes it can lead to very large values (say 5 seconds).
7137 Use this option to put an upper limit on the dynamic timeout
7138 value. Do NOT use this option to always use a fixed (instead
7139 of a dynamic) timeout value. To set a fixed timeout see the
7140 'icp_query_timeout' directive.
7143 NAME: minimum_icp_query_timeout
7147 LOC: Config.Timeout.icp_query_min
7149 Normally the ICP query timeout is determined dynamically. But
7150 sometimes it can lead to very small timeouts, even lower than
7151 the normal latency variance on your link due to traffic.
7152 Use this option to put an lower limit on the dynamic timeout
7153 value. Do NOT use this option to always use a fixed (instead
7154 of a dynamic) timeout value. To set a fixed timeout see the
7155 'icp_query_timeout' directive.
7158 NAME: background_ping_rate
7162 LOC: Config.backgroundPingRate
7164 Controls how often the ICP pings are sent to siblings that
7165 have background-ping set.
7169 MULTICAST ICP OPTIONS
7170 -----------------------------------------------------------------------------
7175 LOC: Config.mcast_group_list
7178 This tag specifies a list of multicast groups which your server
7179 should join to receive multicasted ICP queries.
7181 NOTE! Be very careful what you put here! Be sure you
7182 understand the difference between an ICP _query_ and an ICP
7183 _reply_. This option is to be set only if you want to RECEIVE
7184 multicast queries. Do NOT set this option to SEND multicast
7185 ICP (use cache_peer for that). ICP replies are always sent via
7186 unicast, so this option does not affect whether or not you will
7187 receive replies from multicast group members.
7189 You must be very careful to NOT use a multicast address which
7190 is already in use by another group of caches.
7192 If you are unsure about multicast, please read the Multicast
7193 chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
7195 Usage: mcast_groups 239.128.16.128 224.0.1.20
7197 By default, Squid doesn't listen on any multicast groups.
7200 NAME: mcast_miss_addr
7201 IFDEF: MULTICAST_MISS_STREAM
7203 LOC: Config.mcast_miss.addr
7205 DEFAULT_DOC: disabled.
7207 If you enable this option, every "cache miss" URL will
7208 be sent out on the specified multicast address.
7210 Do not enable this option unless you are are absolutely
7211 certain you understand what you are doing.
7214 NAME: mcast_miss_ttl
7215 IFDEF: MULTICAST_MISS_STREAM
7217 LOC: Config.mcast_miss.ttl
7220 This is the time-to-live value for packets multicasted
7221 when multicasting off cache miss URLs is enabled. By
7222 default this is set to 'site scope', i.e. 16.
7225 NAME: mcast_miss_port
7226 IFDEF: MULTICAST_MISS_STREAM
7228 LOC: Config.mcast_miss.port
7231 This is the port number to be used in conjunction with
7235 NAME: mcast_miss_encode_key
7236 IFDEF: MULTICAST_MISS_STREAM
7238 LOC: Config.mcast_miss.encode_key
7239 DEFAULT: XXXXXXXXXXXXXXXX
7241 The URLs that are sent in the multicast miss stream are
7242 encrypted. This is the encryption key.
7245 NAME: mcast_icp_query_timeout
7249 LOC: Config.Timeout.mcast_icp_query
7251 For multicast peers, Squid regularly sends out ICP "probes" to
7252 count how many other peers are listening on the given multicast
7253 address. This value specifies how long Squid should wait to
7254 count all the replies. The default is 2000 msec, or 2
7259 INTERNAL ICON OPTIONS
7260 -----------------------------------------------------------------------------
7263 NAME: icon_directory
7265 LOC: Config.icons.directory
7266 DEFAULT: @DEFAULT_ICON_DIR@
7268 Where the icons are stored. These are normally kept in
7272 NAME: global_internal_static
7274 LOC: Config.onoff.global_internal_static
7277 This directive controls is Squid should intercept all requests for
7278 /squid-internal-static/ no matter which host the URL is requesting
7279 (default on setting), or if nothing special should be done for
7280 such URLs (off setting). The purpose of this directive is to make
7281 icons etc work better in complex cache hierarchies where it may
7282 not always be possible for all corners in the cache mesh to reach
7283 the server generating a directory listing.
7286 NAME: short_icon_urls
7288 LOC: Config.icons.use_short_names
7291 If this is enabled Squid will use short URLs for icons.
7292 If disabled it will revert to the old behavior of including
7293 it's own name and port in the URL.
7295 If you run a complex cache hierarchy with a mix of Squid and
7296 other proxies you may need to disable this directive.
7301 -----------------------------------------------------------------------------
7304 NAME: error_directory
7306 LOC: Config.errorDirectory
7308 DEFAULT_DOC: Send error pages in the clients preferred language
7310 If you wish to create your own versions of the default
7311 error files to customize them to suit your company copy
7312 the error/template files to another directory and point
7315 WARNING: This option will disable multi-language support
7316 on error pages if used.
7318 The squid developers are interested in making squid available in
7319 a wide variety of languages. If you are making translations for a
7320 language that Squid does not currently provide please consider
7321 contributing your translation back to the project.
7322 http://wiki.squid-cache.org/Translations
7324 The squid developers working on translations are happy to supply drop-in
7325 translated error files in exchange for any new language contributions.
7328 NAME: error_default_language
7329 IFDEF: USE_ERR_LOCALES
7331 LOC: Config.errorDefaultLanguage
7333 DEFAULT_DOC: Generate English language pages.
7335 Set the default language which squid will send error pages in
7336 if no existing translation matches the clients language
7339 If unset (default) generic English will be used.
7341 The squid developers are interested in making squid available in
7342 a wide variety of languages. If you are interested in making
7343 translations for any language see the squid wiki for details.
7344 http://wiki.squid-cache.org/Translations
7347 NAME: error_log_languages
7348 IFDEF: USE_ERR_LOCALES
7350 LOC: Config.errorLogMissingLanguages
7353 Log to cache.log what languages users are attempting to
7354 auto-negotiate for translations.
7356 Successful negotiations are not logged. Only failures
7357 have meaning to indicate that Squid may need an upgrade
7358 of its error page translations.
7361 NAME: err_page_stylesheet
7363 LOC: Config.errorStylesheet
7364 DEFAULT: @DEFAULT_CONFIG_DIR@/errorpage.css
7366 CSS Stylesheet to pattern the display of Squid default error pages.
7368 For information on CSS see http://www.w3.org/Style/CSS/
7373 LOC: Config.errHtmlText
7376 HTML text to include in error messages. Make this a "mailto"
7377 URL to your admin address, or maybe just a link to your
7378 organizations Web page.
7380 To include this in your error messages, you must rewrite
7381 the error template files (found in the "errors" directory).
7382 Wherever you want the 'err_html_text' line to appear,
7383 insert a %L tag in the error template file.
7386 NAME: email_err_data
7389 LOC: Config.onoff.emailErrData
7392 If enabled, information about the occurred error will be
7393 included in the mailto links of the ERR pages (if %W is set)
7394 so that the email body contains the data.
7395 Syntax is <A HREF="mailto:%w%W">%w</A>
7400 LOC: Config.denyInfoList
7403 Usage: deny_info err_page_name acl
7404 or deny_info http://... acl
7405 or deny_info TCP_RESET acl
7407 This can be used to return a ERR_ page for requests which
7408 do not pass the 'http_access' rules. Squid remembers the last
7409 acl it evaluated in http_access, and if a 'deny_info' line exists
7410 for that ACL Squid returns a corresponding error page.
7412 The acl is typically the last acl on the http_access deny line which
7413 denied access. The exceptions to this rule are:
7414 - When Squid needs to request authentication credentials. It's then
7415 the first authentication related acl encountered
7416 - When none of the http_access lines matches. It's then the last
7417 acl processed on the last http_access line.
7418 - When the decision to deny access was made by an adaptation service,
7419 the acl name is the corresponding eCAP or ICAP service_name.
7421 NP: If providing your own custom error pages with error_directory
7422 you may also specify them by your custom file name:
7423 Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
7425 By defaut Squid will send "403 Forbidden". A different 4xx or 5xx
7426 may be specified by prefixing the file name with the code and a colon.
7427 e.g. 404:ERR_CUSTOM_ACCESS_DENIED
7429 Alternatively you can tell Squid to reset the TCP connection
7430 by specifying TCP_RESET.
7432 Or you can specify an error URL or URL pattern. The browsers will
7433 get redirected to the specified URL after formatting tags have
7434 been replaced. Redirect will be done with 302 or 307 according to
7435 HTTP/1.1 specs. A different 3xx code may be specified by prefixing
7436 the URL. e.g. 303:http://example.com/
7439 %a - username (if available. Password NOT included)
7442 %E - Error description
7444 %H - Request domain name
7445 %i - Client IP Address
7447 %o - Message result from external ACL helper
7448 %p - Request Port number
7449 %P - Request Protocol name
7450 %R - Request URL path
7451 %T - Timestamp in RFC 1123 format
7452 %U - Full canonical URL from client
7453 (HTTPS URLs terminate with *)
7454 %u - Full canonical URL from client
7455 %w - Admin email from squid.conf
7457 %% - Literal percent (%) code
7462 OPTIONS INFLUENCING REQUEST FORWARDING
7463 -----------------------------------------------------------------------------
7466 NAME: nonhierarchical_direct
7468 LOC: Config.onoff.nonhierarchical_direct
7471 By default, Squid will send any non-hierarchical requests
7472 (not cacheable request type) direct to origin servers.
7474 When this is set to "off", Squid will prefer to send these
7475 requests to parents.
7477 Note that in most configurations, by turning this off you will only
7478 add latency to these request without any improvement in global hit
7481 This option only sets a preference. If the parent is unavailable a
7482 direct connection to the origin server may still be attempted. To
7483 completely prevent direct connections use never_direct.
7488 LOC: Config.onoff.prefer_direct
7491 Normally Squid tries to use parents for most requests. If you for some
7492 reason like it to first try going direct and only use a parent if
7493 going direct fails set this to on.
7495 By combining nonhierarchical_direct off and prefer_direct on you
7496 can set up Squid to use a parent as a backup path if going direct
7499 Note: If you want Squid to use parents for all requests see
7500 the never_direct directive. prefer_direct only modifies how Squid
7501 acts on cacheable requests.
7504 NAME: cache_miss_revalidate
7508 LOC: Config.onoff.cache_miss_revalidate
7510 RFC 7232 defines a conditional request mechanism to prevent
7511 response objects being unnecessarily transferred over the network.
7512 If that mechanism is used by the client and a cache MISS occurs
7513 it can prevent new cache entries being created.
7515 This option determines whether Squid on cache MISS will pass the
7516 client revalidation request to the server or tries to fetch new
7517 content for caching. It can be useful while the cache is mostly
7518 empty to more quickly have the cache populated by generating
7519 non-conditional GETs.
7521 When set to 'on' (default), Squid will pass all client If-* headers
7522 to the server. This permits server responses without a cacheable
7523 payload to be delivered and on MISS no new cache entry is created.
7525 When set to 'off' and if the request is cacheable, Squid will
7526 remove the clients If-Modified-Since and If-None-Match headers from
7527 the request sent to the server. This requests a 200 status response
7528 from the server to create a new cache entry with.
7533 LOC: Config.accessList.AlwaysDirect
7535 DEFAULT_DOC: Prevent any cache_peer being used for this request.
7537 Usage: always_direct allow|deny [!]aclname ...
7539 Here you can use ACL elements to specify requests which should
7540 ALWAYS be forwarded by Squid to the origin servers without using
7541 any peers. For example, to always directly forward requests for
7542 local servers ignoring any parents or siblings you may have use
7545 acl local-servers dstdomain my.domain.net
7546 always_direct allow local-servers
7548 To always forward FTP requests directly, use
7551 always_direct allow FTP
7553 NOTE: There is a similar, but opposite option named
7554 'never_direct'. You need to be aware that "always_direct deny
7555 foo" is NOT the same thing as "never_direct allow foo". You
7556 may need to use a deny rule to exclude a more-specific case of
7557 some other rule. Example:
7559 acl local-external dstdomain external.foo.net
7560 acl local-servers dstdomain .foo.net
7561 always_direct deny local-external
7562 always_direct allow local-servers
7564 NOTE: If your goal is to make the client forward the request
7565 directly to the origin server bypassing Squid then this needs
7566 to be done in the client configuration. Squid configuration
7567 can only tell Squid how Squid should fetch the object.
7569 NOTE: This directive is not related to caching. The replies
7570 is cached as usual even if you use always_direct. To not cache
7571 the replies see the 'cache' directive.
7573 This clause supports both fast and slow acl types.
7574 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7579 LOC: Config.accessList.NeverDirect
7581 DEFAULT_DOC: Allow DNS results to be used for this request.
7583 Usage: never_direct allow|deny [!]aclname ...
7585 never_direct is the opposite of always_direct. Please read
7586 the description for always_direct if you have not already.
7588 With 'never_direct' you can use ACL elements to specify
7589 requests which should NEVER be forwarded directly to origin
7590 servers. For example, to force the use of a proxy for all
7591 requests, except those in your local domain use something like:
7593 acl local-servers dstdomain .foo.net
7594 never_direct deny local-servers
7595 never_direct allow all
7597 or if Squid is inside a firewall and there are local intranet
7598 servers inside the firewall use something like:
7600 acl local-intranet dstdomain .foo.net
7601 acl local-external dstdomain external.foo.net
7602 always_direct deny local-external
7603 always_direct allow local-intranet
7604 never_direct allow all
7606 This clause supports both fast and slow acl types.
7607 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7611 ADVANCED NETWORKING OPTIONS
7612 -----------------------------------------------------------------------------
7615 NAME: incoming_udp_average incoming_icp_average
7618 LOC: Config.comm_incoming.udp.average
7620 Heavy voodoo here. I can't even believe you are reading this.
7621 Are you crazy? Don't even think about adjusting these unless
7622 you understand the algorithms in comm_select.c first!
7625 NAME: incoming_tcp_average incoming_http_average
7628 LOC: Config.comm_incoming.tcp.average
7630 Heavy voodoo here. I can't even believe you are reading this.
7631 Are you crazy? Don't even think about adjusting these unless
7632 you understand the algorithms in comm_select.c first!
7635 NAME: incoming_dns_average
7638 LOC: Config.comm_incoming.dns.average
7640 Heavy voodoo here. I can't even believe you are reading this.
7641 Are you crazy? Don't even think about adjusting these unless
7642 you understand the algorithms in comm_select.c first!
7645 NAME: min_udp_poll_cnt min_icp_poll_cnt
7648 LOC: Config.comm_incoming.udp.min_poll
7650 Heavy voodoo here. I can't even believe you are reading this.
7651 Are you crazy? Don't even think about adjusting these unless
7652 you understand the algorithms in comm_select.c first!
7655 NAME: min_dns_poll_cnt
7658 LOC: Config.comm_incoming.dns.min_poll
7660 Heavy voodoo here. I can't even believe you are reading this.
7661 Are you crazy? Don't even think about adjusting these unless
7662 you understand the algorithms in comm_select.c first!
7665 NAME: min_tcp_poll_cnt min_http_poll_cnt
7668 LOC: Config.comm_incoming.tcp.min_poll
7670 Heavy voodoo here. I can't even believe you are reading this.
7671 Are you crazy? Don't even think about adjusting these unless
7672 you understand the algorithms in comm_select.c first!
7678 LOC: Config.accept_filter
7682 The name of an accept(2) filter to install on Squid's
7683 listen socket(s). This feature is perhaps specific to
7684 FreeBSD and requires support in the kernel.
7686 The 'httpready' filter delays delivering new connections
7687 to Squid until a full HTTP request has been received.
7688 See the accf_http(9) man page for details.
7690 The 'dataready' filter delays delivering new connections
7691 to Squid until there is some data to process.
7692 See the accf_dataready(9) man page for details.
7696 The 'data' filter delays delivering of new connections
7697 to Squid until there is some data to process by TCP_ACCEPT_DEFER.
7698 You may optionally specify a number of seconds to wait by
7699 'data=N' where N is the number of seconds. Defaults to 30
7700 if not specified. See the tcp(7) man page for details.
7703 accept_filter httpready
7708 NAME: client_ip_max_connections
7710 LOC: Config.client_ip_max_connections
7712 DEFAULT_DOC: No limit.
7714 Set an absolute limit on the number of connections a single
7715 client IP can use. Any more than this and Squid will begin to drop
7716 new connections from the client until it closes some links.
7718 Note that this is a global limit. It affects all HTTP, HTCP, Gopher and FTP
7719 connections from the client. For finer control use the ACL access controls.
7721 Requires client_db to be enabled (the default).
7723 WARNING: This may noticably slow down traffic received via external proxies
7724 or NAT devices and cause them to rebound error messages back to their clients.
7727 NAME: tcp_recv_bufsize
7731 DEFAULT_DOC: Use operating system TCP defaults.
7732 LOC: Config.tcpRcvBufsz
7734 Size of receive buffer to set for TCP sockets. Probably just
7735 as easy to change your kernel's default.
7736 Omit from squid.conf to use the default buffer size.
7741 -----------------------------------------------------------------------------
7748 LOC: Adaptation::Icap::TheConfig.onoff
7751 If you want to enable the ICAP module support, set this to on.
7754 NAME: icap_connect_timeout
7757 LOC: Adaptation::Icap::TheConfig.connect_timeout_raw
7760 This parameter specifies how long to wait for the TCP connect to
7761 the requested ICAP server to complete before giving up and either
7762 terminating the HTTP transaction or bypassing the failure.
7764 The default for optional services is peer_connect_timeout.
7765 The default for essential services is connect_timeout.
7766 If this option is explicitly set, its value applies to all services.
7769 NAME: icap_io_timeout
7773 DEFAULT_DOC: Use read_timeout.
7774 LOC: Adaptation::Icap::TheConfig.io_timeout_raw
7777 This parameter specifies how long to wait for an I/O activity on
7778 an established, active ICAP connection before giving up and
7779 either terminating the HTTP transaction or bypassing the
7783 NAME: icap_service_failure_limit
7784 COMMENT: limit [in memory-depth time-units]
7785 TYPE: icap_service_failure_limit
7787 LOC: Adaptation::Icap::TheConfig
7790 The limit specifies the number of failures that Squid tolerates
7791 when establishing a new TCP connection with an ICAP service. If
7792 the number of failures exceeds the limit, the ICAP service is
7793 not used for new ICAP requests until it is time to refresh its
7796 A negative value disables the limit. Without the limit, an ICAP
7797 service will not be considered down due to connectivity failures
7798 between ICAP OPTIONS requests.
7800 Squid forgets ICAP service failures older than the specified
7801 value of memory-depth. The memory fading algorithm
7802 is approximate because Squid does not remember individual
7803 errors but groups them instead, splitting the option
7804 value into ten time slots of equal length.
7806 When memory-depth is 0 and by default this option has no
7807 effect on service failure expiration.
7809 Squid always forgets failures when updating service settings
7810 using an ICAP OPTIONS transaction, regardless of this option
7814 # suspend service usage after 10 failures in 5 seconds:
7815 icap_service_failure_limit 10 in 5 seconds
7818 NAME: icap_service_revival_delay
7821 LOC: Adaptation::Icap::TheConfig.service_revival_delay
7824 The delay specifies the number of seconds to wait after an ICAP
7825 OPTIONS request failure before requesting the options again. The
7826 failed ICAP service is considered "down" until fresh OPTIONS are
7829 The actual delay cannot be smaller than the hardcoded minimum
7830 delay of 30 seconds.
7833 NAME: icap_preview_enable
7837 LOC: Adaptation::Icap::TheConfig.preview_enable
7840 The ICAP Preview feature allows the ICAP server to handle the
7841 HTTP message by looking only at the beginning of the message body
7842 or even without receiving the body at all. In some environments,
7843 previews greatly speedup ICAP processing.
7845 During an ICAP OPTIONS transaction, the server may tell Squid what
7846 HTTP messages should be previewed and how big the preview should be.
7847 Squid will not use Preview if the server did not request one.
7849 To disable ICAP Preview for all ICAP services, regardless of
7850 individual ICAP server OPTIONS responses, set this option to "off".
7852 icap_preview_enable off
7855 NAME: icap_preview_size
7858 LOC: Adaptation::Icap::TheConfig.preview_size
7860 DEFAULT_DOC: No preview sent.
7862 The default size of preview data to be sent to the ICAP server.
7863 This value might be overwritten on a per server basis by OPTIONS requests.
7866 NAME: icap_206_enable
7870 LOC: Adaptation::Icap::TheConfig.allow206_enable
7873 206 (Partial Content) responses is an ICAP extension that allows the
7874 ICAP agents to optionally combine adapted and original HTTP message
7875 content. The decision to combine is postponed until the end of the
7876 ICAP response. Squid supports Partial Content extension by default.
7878 Activation of the Partial Content extension is negotiated with each
7879 ICAP service during OPTIONS exchange. Most ICAP servers should handle
7880 negotation correctly even if they do not support the extension, but
7881 some might fail. To disable Partial Content support for all ICAP
7882 services and to avoid any negotiation, set this option to "off".
7888 NAME: icap_default_options_ttl
7891 LOC: Adaptation::Icap::TheConfig.default_options_ttl
7894 The default TTL value for ICAP OPTIONS responses that don't have
7895 an Options-TTL header.
7898 NAME: icap_persistent_connections
7902 LOC: Adaptation::Icap::TheConfig.reuse_connections
7905 Whether or not Squid should use persistent connections to
7909 NAME: adaptation_send_client_ip icap_send_client_ip
7911 IFDEF: USE_ADAPTATION
7913 LOC: Adaptation::Config::send_client_ip
7916 If enabled, Squid shares HTTP client IP information with adaptation
7917 services. For ICAP, Squid adds the X-Client-IP header to ICAP requests.
7918 For eCAP, Squid sets the libecap::metaClientIp transaction option.
7920 See also: adaptation_uses_indirect_client
7923 NAME: adaptation_send_username icap_send_client_username
7925 IFDEF: USE_ADAPTATION
7927 LOC: Adaptation::Config::send_username
7930 This sends authenticated HTTP client username (if available) to
7931 the adaptation service.
7933 For ICAP, the username value is encoded based on the
7934 icap_client_username_encode option and is sent using the header
7935 specified by the icap_client_username_header option.
7938 NAME: icap_client_username_header
7941 LOC: Adaptation::Icap::TheConfig.client_username_header
7942 DEFAULT: X-Client-Username
7944 ICAP request header name to use for adaptation_send_username.
7947 NAME: icap_client_username_encode
7951 LOC: Adaptation::Icap::TheConfig.client_username_encode
7954 Whether to base64 encode the authenticated client username.
7958 TYPE: icap_service_type
7960 LOC: Adaptation::Icap::TheConfig
7963 Defines a single ICAP service using the following format:
7965 icap_service id vectoring_point uri [option ...]
7968 an opaque identifier or name which is used to direct traffic to
7969 this specific service. Must be unique among all adaptation
7970 services in squid.conf.
7972 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
7973 This specifies at which point of transaction processing the
7974 ICAP service should be activated. *_postcache vectoring points
7975 are not yet supported.
7977 uri: icap://servername:port/servicepath
7978 ICAP server and service location.
7980 ICAP does not allow a single service to handle both REQMOD and RESPMOD
7981 transactions. Squid does not enforce that requirement. You can specify
7982 services with the same service_url and different vectoring_points. You
7983 can even specify multiple identical services as long as their
7984 service_names differ.
7986 To activate a service, use the adaptation_access directive. To group
7987 services, use adaptation_service_chain and adaptation_service_set.
7989 Service options are separated by white space. ICAP services support
7990 the following name=value options:
7993 If set to 'on' or '1', the ICAP service is treated as
7994 optional. If the service cannot be reached or malfunctions,
7995 Squid will try to ignore any errors and process the message as
7996 if the service was not enabled. No all ICAP errors can be
7997 bypassed. If set to 0, the ICAP service is treated as
7998 essential and all ICAP errors will result in an error page
7999 returned to the HTTP client.
8001 Bypass is off by default: services are treated as essential.
8004 If set to 'on' or '1', the ICAP service is allowed to
8005 dynamically change the current message adaptation plan by
8006 returning a chain of services to be used next. The services
8007 are specified using the X-Next-Services ICAP response header
8008 value, formatted as a comma-separated list of service names.
8009 Each named service should be configured in squid.conf. Other
8010 services are ignored. An empty X-Next-Services value results
8011 in an empty plan which ends the current adaptation.
8013 Dynamic adaptation plan may cross or cover multiple supported
8014 vectoring points in their natural processing order.
8016 Routing is not allowed by default: the ICAP X-Next-Services
8017 response header is ignored.
8020 Only has effect on split-stack systems. The default on those systems
8021 is to use IPv4-only connections. When set to 'on' this option will
8022 make Squid use IPv6-only connections to contact this ICAP service.
8024 on-overload=block|bypass|wait|force
8025 If the service Max-Connections limit has been reached, do
8026 one of the following for each new ICAP transaction:
8027 * block: send an HTTP error response to the client
8028 * bypass: ignore the "over-connected" ICAP service
8029 * wait: wait (in a FIFO queue) for an ICAP connection slot
8030 * force: proceed, ignoring the Max-Connections limit
8032 In SMP mode with N workers, each worker assumes the service
8033 connection limit is Max-Connections/N, even though not all
8034 workers may use a given service.
8036 The default value is "bypass" if service is bypassable,
8037 otherwise it is set to "wait".
8041 Use the given number as the Max-Connections limit, regardless
8042 of the Max-Connections value given by the service, if any.
8044 Older icap_service format without optional named parameters is
8045 deprecated but supported for backward compatibility.
8048 icap_service svcBlocker reqmod_precache icap://icap1.mydomain.net:1344/reqmod bypass=0
8049 icap_service svcLogger reqmod_precache icap://icap2.mydomain.net:1344/respmod routing=on
8053 TYPE: icap_class_type
8058 This deprecated option was documented to define an ICAP service
8059 chain, even though it actually defined a set of similar, redundant
8060 services, and the chains were not supported.
8062 To define a set of redundant services, please use the
8063 adaptation_service_set directive. For service chains, use
8064 adaptation_service_chain.
8068 TYPE: icap_access_type
8073 This option is deprecated. Please use adaptation_access, which
8074 has the same ICAP functionality, but comes with better
8075 documentation, and eCAP support.
8080 -----------------------------------------------------------------------------
8087 LOC: Adaptation::Ecap::TheConfig.onoff
8090 Controls whether eCAP support is enabled.
8094 TYPE: ecap_service_type
8096 LOC: Adaptation::Ecap::TheConfig
8099 Defines a single eCAP service
8101 ecap_service id vectoring_point uri [option ...]
8104 an opaque identifier or name which is used to direct traffic to
8105 this specific service. Must be unique among all adaptation
8106 services in squid.conf.
8108 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
8109 This specifies at which point of transaction processing the
8110 eCAP service should be activated. *_postcache vectoring points
8111 are not yet supported.
8113 uri: ecap://vendor/service_name?custom&cgi=style¶meters=optional
8114 Squid uses the eCAP service URI to match this configuration
8115 line with one of the dynamically loaded services. Each loaded
8116 eCAP service must have a unique URI. Obtain the right URI from
8117 the service provider.
8119 To activate a service, use the adaptation_access directive. To group
8120 services, use adaptation_service_chain and adaptation_service_set.
8122 Service options are separated by white space. eCAP services support
8123 the following name=value options:
8126 If set to 'on' or '1', the eCAP service is treated as optional.
8127 If the service cannot be reached or malfunctions, Squid will try
8128 to ignore any errors and process the message as if the service
8129 was not enabled. No all eCAP errors can be bypassed.
8130 If set to 'off' or '0', the eCAP service is treated as essential
8131 and all eCAP errors will result in an error page returned to the
8134 Bypass is off by default: services are treated as essential.
8137 If set to 'on' or '1', the eCAP service is allowed to
8138 dynamically change the current message adaptation plan by
8139 returning a chain of services to be used next.
8141 Dynamic adaptation plan may cross or cover multiple supported
8142 vectoring points in their natural processing order.
8144 Routing is not allowed by default.
8146 Older ecap_service format without optional named parameters is
8147 deprecated but supported for backward compatibility.
8151 ecap_service s1 reqmod_precache ecap://filters.R.us/leakDetector?on_error=block bypass=off
8152 ecap_service s2 respmod_precache ecap://filters.R.us/virusFilter config=/etc/vf.cfg bypass=on
8155 NAME: loadable_modules
8157 IFDEF: USE_LOADABLE_MODULES
8158 LOC: Config.loadable_module_names
8161 Instructs Squid to load the specified dynamic module(s) or activate
8162 preloaded module(s).
8164 loadable_modules @DEFAULT_PREFIX@/lib/MinimalAdapter.so
8168 MESSAGE ADAPTATION OPTIONS
8169 -----------------------------------------------------------------------------
8172 NAME: adaptation_service_set
8173 TYPE: adaptation_service_set_type
8174 IFDEF: USE_ADAPTATION
8179 Configures an ordered set of similar, redundant services. This is
8180 useful when hot standby or backup adaptation servers are available.
8182 adaptation_service_set set_name service_name1 service_name2 ...
8184 The named services are used in the set declaration order. The first
8185 applicable adaptation service from the set is used first. The next
8186 applicable service is tried if and only if the transaction with the
8187 previous service fails and the message waiting to be adapted is still
8190 When adaptation starts, broken services are ignored as if they were
8191 not a part of the set. A broken service is a down optional service.
8193 The services in a set must be attached to the same vectoring point
8194 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
8196 If all services in a set are optional then adaptation failures are
8197 bypassable. If all services in the set are essential, then a
8198 transaction failure with one service may still be retried using
8199 another service from the set, but when all services fail, the master
8200 transaction fails as well.
8202 A set may contain a mix of optional and essential services, but that
8203 is likely to lead to surprising results because broken services become
8204 ignored (see above), making previously bypassable failures fatal.
8205 Technically, it is the bypassability of the last failed service that
8208 See also: adaptation_access adaptation_service_chain
8211 adaptation_service_set svcBlocker urlFilterPrimary urlFilterBackup
8212 adaptation service_set svcLogger loggerLocal loggerRemote
8215 NAME: adaptation_service_chain
8216 TYPE: adaptation_service_chain_type
8217 IFDEF: USE_ADAPTATION
8222 Configures a list of complementary services that will be applied
8223 one-by-one, forming an adaptation chain or pipeline. This is useful
8224 when Squid must perform different adaptations on the same message.
8226 adaptation_service_chain chain_name service_name1 svc_name2 ...
8228 The named services are used in the chain declaration order. The first
8229 applicable adaptation service from the chain is used first. The next
8230 applicable service is applied to the successful adaptation results of
8231 the previous service in the chain.
8233 When adaptation starts, broken services are ignored as if they were
8234 not a part of the chain. A broken service is a down optional service.
8236 Request satisfaction terminates the adaptation chain because Squid
8237 does not currently allow declaration of RESPMOD services at the
8238 "reqmod_precache" vectoring point (see icap_service or ecap_service).
8240 The services in a chain must be attached to the same vectoring point
8241 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
8243 A chain may contain a mix of optional and essential services. If an
8244 essential adaptation fails (or the failure cannot be bypassed for
8245 other reasons), the master transaction fails. Otherwise, the failure
8246 is bypassed as if the failed adaptation service was not in the chain.
8248 See also: adaptation_access adaptation_service_set
8251 adaptation_service_chain svcRequest requestLogger urlFilter leakDetector
8254 NAME: adaptation_access
8255 TYPE: adaptation_access_type
8256 IFDEF: USE_ADAPTATION
8259 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
8261 Sends an HTTP transaction to an ICAP or eCAP adaptation service.
8263 adaptation_access service_name allow|deny [!]aclname...
8264 adaptation_access set_name allow|deny [!]aclname...
8266 At each supported vectoring point, the adaptation_access
8267 statements are processed in the order they appear in this
8268 configuration file. Statements pointing to the following services
8269 are ignored (i.e., skipped without checking their ACL):
8271 - services serving different vectoring points
8272 - "broken-but-bypassable" services
8273 - "up" services configured to ignore such transactions
8274 (e.g., based on the ICAP Transfer-Ignore header).
8276 When a set_name is used, all services in the set are checked
8277 using the same rules, to find the first applicable one. See
8278 adaptation_service_set for details.
8280 If an access list is checked and there is a match, the
8281 processing stops: For an "allow" rule, the corresponding
8282 adaptation service is used for the transaction. For a "deny"
8283 rule, no adaptation service is activated.
8285 It is currently not possible to apply more than one adaptation
8286 service at the same vectoring point to the same HTTP transaction.
8288 See also: icap_service and ecap_service
8291 adaptation_access service_1 allow all
8294 NAME: adaptation_service_iteration_limit
8296 IFDEF: USE_ADAPTATION
8297 LOC: Adaptation::Config::service_iteration_limit
8300 Limits the number of iterations allowed when applying adaptation
8301 services to a message. If your longest adaptation set or chain
8302 may have more than 16 services, increase the limit beyond its
8303 default value of 16. If detecting infinite iteration loops sooner
8304 is critical, make the iteration limit match the actual number
8305 of services in your longest adaptation set or chain.
8307 Infinite adaptation loops are most likely with routing services.
8309 See also: icap_service routing=1
8312 NAME: adaptation_masterx_shared_names
8314 IFDEF: USE_ADAPTATION
8315 LOC: Adaptation::Config::masterx_shared_name
8318 For each master transaction (i.e., the HTTP request and response
8319 sequence, including all related ICAP and eCAP exchanges), Squid
8320 maintains a table of metadata. The table entries are (name, value)
8321 pairs shared among eCAP and ICAP exchanges. The table is destroyed
8322 with the master transaction.
8324 This option specifies the table entry names that Squid must accept
8325 from and forward to the adaptation transactions.
8327 An ICAP REQMOD or RESPMOD transaction may set an entry in the
8328 shared table by returning an ICAP header field with a name
8329 specified in adaptation_masterx_shared_names.
8331 An eCAP REQMOD or RESPMOD transaction may set an entry in the
8332 shared table by implementing the libecap::visitEachOption() API
8333 to provide an option with a name specified in
8334 adaptation_masterx_shared_names.
8336 Squid will store and forward the set entry to subsequent adaptation
8337 transactions within the same master transaction scope.
8339 Only one shared entry name is supported at this time.
8342 # share authentication information among ICAP services
8343 adaptation_masterx_shared_names X-Subscriber-ID
8346 NAME: adaptation_meta
8348 IFDEF: USE_ADAPTATION
8349 LOC: Adaptation::Config::metaHeaders
8352 This option allows Squid administrator to add custom ICAP request
8353 headers or eCAP options to Squid ICAP requests or eCAP transactions.
8354 Use it to pass custom authentication tokens and other
8355 transaction-state related meta information to an ICAP/eCAP service.
8357 The addition of a meta header is ACL-driven:
8358 adaptation_meta name value [!]aclname ...
8360 Processing for a given header name stops after the first ACL list match.
8361 Thus, it is impossible to add two headers with the same name. If no ACL
8362 lists match for a given header name, no such header is added. For
8365 # do not debug transactions except for those that need debugging
8366 adaptation_meta X-Debug 1 needs_debugging
8368 # log all transactions except for those that must remain secret
8369 adaptation_meta X-Log 1 !keep_secret
8371 # mark transactions from users in the "G 1" group
8372 adaptation_meta X-Authenticated-Groups "G 1" authed_as_G1
8374 The "value" parameter may be a regular squid.conf token or a "double
8375 quoted string". Within the quoted string, use backslash (\) to escape
8376 any character, which is currently only useful for escaping backslashes
8377 and double quotes. For example,
8378 "this string has one backslash (\\) and two \"quotes\""
8380 Used adaptation_meta header values may be logged via %note
8381 logformat code. If multiple adaptation_meta headers with the same name
8382 are used during master transaction lifetime, the header values are
8383 logged in the order they were used and duplicate values are ignored
8384 (only the first repeated value will be logged).
8390 LOC: Adaptation::Icap::TheConfig.repeat
8391 DEFAULT_IF_NONE: deny all
8393 This ACL determines which retriable ICAP transactions are
8394 retried. Transactions that received a complete ICAP response
8395 and did not have to consume or produce HTTP bodies to receive
8396 that response are usually retriable.
8398 icap_retry allow|deny [!]aclname ...
8400 Squid automatically retries some ICAP I/O timeouts and errors
8401 due to persistent connection race conditions.
8403 See also: icap_retry_limit
8406 NAME: icap_retry_limit
8409 LOC: Adaptation::Icap::TheConfig.repeat_limit
8411 DEFAULT_DOC: No retries are allowed.
8413 Limits the number of retries allowed.
8415 Communication errors due to persistent connection race
8416 conditions are unavoidable, automatically retried, and do not
8417 count against this limit.
8419 See also: icap_retry
8425 -----------------------------------------------------------------------------
8428 NAME: check_hostnames
8431 LOC: Config.onoff.check_hostnames
8433 For security and stability reasons Squid can check
8434 hostnames for Internet standard RFC compliance. If you want
8435 Squid to perform these checks turn this directive on.
8438 NAME: allow_underscore
8441 LOC: Config.onoff.allow_underscore
8443 Underscore characters is not strictly allowed in Internet hostnames
8444 but nevertheless used by many sites. Set this to off if you want
8445 Squid to be strict about the standard.
8446 This check is performed only when check_hostnames is set to on.
8449 NAME: dns_retransmit_interval
8452 LOC: Config.Timeout.idns_retransmit
8454 Initial retransmit interval for DNS queries. The interval is
8455 doubled each time all configured DNS servers have been tried.
8461 LOC: Config.Timeout.idns_query
8463 DNS Query timeout. If no response is received to a DNS query
8464 within this time all DNS servers for the queried domain
8465 are assumed to be unavailable.
8468 NAME: dns_packet_max
8470 DEFAULT_DOC: EDNS disabled
8472 LOC: Config.dns.packet_max
8474 Maximum number of bytes packet size to advertise via EDNS.
8475 Set to "none" to disable EDNS large packet support.
8477 For legacy reasons DNS UDP replies will default to 512 bytes which
8478 is too small for many responses. EDNS provides a means for Squid to
8479 negotiate receiving larger responses back immediately without having
8480 to failover with repeat requests. Responses larger than this limit
8481 will retain the old behaviour of failover to TCP DNS.
8483 Squid has no real fixed limit internally, but allowing packet sizes
8484 over 1500 bytes requires network jumbogram support and is usually not
8487 WARNING: The RFC also indicates that some older resolvers will reply
8488 with failure of the whole request if the extension is added. Some
8489 resolvers have already been identified which will reply with mangled
8490 EDNS response on occasion. Usually in response to many-KB jumbogram
8491 sizes being advertised by Squid.
8492 Squid will currently treat these both as an unable-to-resolve domain
8493 even if it would be resolvable without EDNS.
8500 DEFAULT_DOC: Search for single-label domain names is disabled.
8501 LOC: Config.onoff.res_defnames
8503 Normally the RES_DEFNAMES resolver option is disabled
8504 (see res_init(3)). This prevents caches in a hierarchy
8505 from interpreting single-component hostnames locally. To allow
8506 Squid to handle single-component names, enable this option.
8509 NAME: dns_multicast_local
8513 DEFAULT_DOC: Search for .local and .arpa names is disabled.
8514 LOC: Config.onoff.dns_mdns
8516 When set to on, Squid sends multicast DNS lookups on the local
8517 network for domains ending in .local and .arpa.
8518 This enables local servers and devices to be contacted in an
8519 ad-hoc or zero-configuration network environment.
8522 NAME: dns_nameservers
8525 DEFAULT_DOC: Use operating system definitions
8526 LOC: Config.dns_nameservers
8528 Use this if you want to specify a list of DNS name servers
8529 (IP addresses) to use instead of those given in your
8530 /etc/resolv.conf file.
8532 On Windows platforms, if no value is specified here or in
8533 the /etc/resolv.conf file, the list of DNS name servers are
8534 taken from the Windows registry, both static and dynamic DHCP
8535 configurations are supported.
8537 Example: dns_nameservers 10.0.0.1 192.172.0.4
8542 DEFAULT: @DEFAULT_HOSTS@
8543 LOC: Config.etcHostsPath
8545 Location of the host-local IP name-address associations
8546 database. Most Operating Systems have such a file on different
8548 - Un*X & Linux: /etc/hosts
8549 - Windows NT/2000: %SystemRoot%\system32\drivers\etc\hosts
8550 (%SystemRoot% value install default is c:\winnt)
8551 - Windows XP/2003: %SystemRoot%\system32\drivers\etc\hosts
8552 (%SystemRoot% value install default is c:\windows)
8553 - Windows 9x/Me: %windir%\hosts
8554 (%windir% value is usually c:\windows)
8555 - Cygwin: /etc/hosts
8557 The file contains newline-separated definitions, in the
8558 form ip_address_in_dotted_form name [name ...] names are
8559 whitespace-separated. Lines beginning with an hash (#)
8560 character are comments.
8562 The file is checked at startup and upon configuration.
8563 If set to 'none', it won't be checked.
8564 If append_domain is used, that domain will be added to
8565 domain-local (i.e. not containing any dot character) host
8571 LOC: Config.appendDomain
8573 DEFAULT_DOC: Use operating system definitions
8575 Appends local domain name to hostnames without any dots in
8576 them. append_domain must begin with a period.
8578 Be warned there are now Internet names with no dots in
8579 them using only top-domain names, so setting this may
8580 cause some Internet sites to become unavailable.
8583 append_domain .yourdomain.com
8586 NAME: ignore_unknown_nameservers
8588 LOC: Config.onoff.ignore_unknown_nameservers
8591 By default Squid checks that DNS responses are received
8592 from the same IP addresses they are sent to. If they
8593 don't match, Squid ignores the response and writes a warning
8594 message to cache.log. You can allow responses from unknown
8595 nameservers by setting this option to 'off'.
8601 LOC: Config.dns.v4_first
8603 With the IPv6 Internet being as fast or faster than IPv4 Internet
8604 for most networks Squid prefers to contact websites over IPv6.
8606 This option reverses the order of preference to make Squid contact
8607 dual-stack websites over IPv4 first. Squid will still perform both
8608 IPv6 and IPv4 DNS lookups before connecting.
8611 This option will restrict the situations under which IPv6
8612 connectivity is used (and tested). Hiding network problems
8613 which would otherwise be detected and warned about.
8617 COMMENT: (number of entries)
8620 LOC: Config.ipcache.size
8622 Maximum number of DNS IP cache entries.
8629 LOC: Config.ipcache.low
8636 LOC: Config.ipcache.high
8638 The size, low-, and high-water marks for the IP cache.
8641 NAME: fqdncache_size
8642 COMMENT: (number of entries)
8645 LOC: Config.fqdncache.size
8647 Maximum number of FQDN cache entries.
8652 -----------------------------------------------------------------------------
8655 NAME: configuration_includes_quoted_values
8657 TYPE: configuration_includes_quoted_values
8659 LOC: ConfigParser::RecognizeQuotedValues
8661 If set, Squid will recognize each "quoted string" after a configuration
8662 directive as a single parameter. The quotes are stripped before the
8663 parameter value is interpreted or used.
8664 See "Values with spaces, quotes, and other special characters"
8665 section for more details.
8672 LOC: Config.onoff.mem_pools
8674 If set, Squid will keep pools of allocated (but unused) memory
8675 available for future use. If memory is a premium on your
8676 system and you believe your malloc library outperforms Squid
8677 routines, disable this.
8680 NAME: memory_pools_limit
8684 LOC: Config.MemPools.limit
8686 Used only with memory_pools on:
8687 memory_pools_limit 50 MB
8689 If set to a non-zero value, Squid will keep at most the specified
8690 limit of allocated (but unused) memory in memory pools. All free()
8691 requests that exceed this limit will be handled by your malloc
8692 library. Squid does not pre-allocate any memory, just safe-keeps
8693 objects that otherwise would be free()d. Thus, it is safe to set
8694 memory_pools_limit to a reasonably high value even if your
8695 configuration will use less memory.
8697 If set to none, Squid will keep all memory it can. That is, there
8698 will be no limit on the total amount of memory used for safe-keeping.
8700 To disable memory allocation optimization, do not set
8701 memory_pools_limit to 0 or none. Set memory_pools to "off" instead.
8703 An overhead for maintaining memory pools is not taken into account
8704 when the limit is checked. This overhead is close to four bytes per
8705 object kept. However, pools may actually _save_ memory because of
8706 reduced memory thrashing in your malloc library.
8710 COMMENT: on|off|transparent|truncate|delete
8713 LOC: opt_forwarded_for
8715 If set to "on", Squid will append your client's IP address
8716 in the HTTP requests it forwards. By default it looks like:
8718 X-Forwarded-For: 192.1.2.3
8720 If set to "off", it will appear as
8722 X-Forwarded-For: unknown
8724 If set to "transparent", Squid will not alter the
8725 X-Forwarded-For header in any way.
8727 If set to "delete", Squid will delete the entire
8728 X-Forwarded-For header.
8730 If set to "truncate", Squid will remove all existing
8731 X-Forwarded-For entries, and place the client IP as the sole entry.
8734 NAME: cachemgr_passwd
8735 TYPE: cachemgrpasswd
8737 DEFAULT_DOC: No password. Actions which require password are denied.
8738 LOC: Config.passwd_list
8740 Specify passwords for cachemgr operations.
8742 Usage: cachemgr_passwd password action action ...
8744 Some valid actions are (see cache manager menu for a full list):
8784 * Indicates actions which will not be performed without a
8785 valid password, others can be performed if not listed here.
8787 To disable an action, set the password to "disable".
8788 To allow performing an action without a password, set the
8791 Use the keyword "all" to set the same password for all actions.
8794 cachemgr_passwd secret shutdown
8795 cachemgr_passwd lesssssssecret info stats/objects
8796 cachemgr_passwd disable all
8803 LOC: Config.onoff.client_db
8805 If you want to disable collecting per-client statistics,
8806 turn off client_db here.
8809 NAME: refresh_all_ims
8813 LOC: Config.onoff.refresh_all_ims
8815 When you enable this option, squid will always check
8816 the origin server for an update when a client sends an
8817 If-Modified-Since request. Many browsers use IMS
8818 requests when the user requests a reload, and this
8819 ensures those clients receive the latest version.
8821 By default (off), squid may return a Not Modified response
8822 based on the age of the cached version.
8825 NAME: reload_into_ims
8826 IFDEF: USE_HTTP_VIOLATIONS
8830 LOC: Config.onoff.reload_into_ims
8832 When you enable this option, client no-cache or ``reload''
8833 requests will be changed to If-Modified-Since requests.
8834 Doing this VIOLATES the HTTP standard. Enabling this
8835 feature could make you liable for problems which it
8838 see also refresh_pattern for a more selective approach.
8841 NAME: connect_retries
8843 LOC: Config.connect_retries
8845 DEFAULT_DOC: Do not retry failed connections.
8847 This sets the maximum number of connection attempts made for each
8848 TCP connection. The connect_retries attempts must all still
8849 complete within the connection timeout period.
8851 The default is not to re-try if the first connection attempt fails.
8852 The (not recommended) maximum is 10 tries.
8854 A warning message will be generated if it is set to a too-high
8855 value and the configured value will be over-ridden.
8857 Note: These re-tries are in addition to forward_max_tries
8858 which limit how many different addresses may be tried to find
8862 NAME: retry_on_error
8864 LOC: Config.retry.onerror
8867 If set to ON Squid will automatically retry requests when
8868 receiving an error response with status 403 (Forbidden),
8869 500 (Internal Error), 501 or 503 (Service not available).
8870 Status 502 and 504 (Gateway errors) are always retried.
8872 This is mainly useful if you are in a complex cache hierarchy to
8873 work around access control errors.
8875 NOTE: This retry will attempt to find another working destination.
8876 Which is different from the server which just failed.
8879 NAME: as_whois_server
8881 LOC: Config.as_whois_server
8882 DEFAULT: whois.ra.net
8884 WHOIS server to query for AS numbers. NOTE: AS numbers are
8885 queried only when Squid starts up, not for every request.
8890 LOC: Config.onoff.offline
8893 Enable this option and Squid will never try to validate cached
8897 NAME: uri_whitespace
8898 TYPE: uri_whitespace
8899 LOC: Config.uri_whitespace
8902 What to do with requests that have whitespace characters in the
8905 strip: The whitespace characters are stripped out of the URL.
8906 This is the behavior recommended by RFC2396 and RFC3986
8907 for tolerant handling of generic URI.
8908 NOTE: This is one difference between generic URI and HTTP URLs.
8910 deny: The request is denied. The user receives an "Invalid
8912 This is the behaviour recommended by RFC2616 for safe
8913 handling of HTTP request URL.
8915 allow: The request is allowed and the URI is not changed. The
8916 whitespace characters remain in the URI. Note the
8917 whitespace is passed to redirector processes if they
8919 Note this may be considered a violation of RFC2616
8920 request parsing where whitespace is prohibited in the
8923 encode: The request is allowed and the whitespace characters are
8924 encoded according to RFC1738.
8926 chop: The request is allowed and the URI is chopped at the
8930 NOTE the current Squid implementation of encode and chop violates
8931 RFC2616 by not using a 301 redirect after altering the URL.
8936 LOC: Config.chroot_dir
8939 Specifies a directory where Squid should do a chroot() while
8940 initializing. This also causes Squid to fully drop root
8941 privileges after initializing. This means, for example, if you
8942 use a HTTP port less than 1024 and try to reconfigure, you may
8943 get an error saying that Squid can not open the port.
8946 NAME: balance_on_multiple_ip
8948 LOC: Config.onoff.balance_on_multiple_ip
8951 Modern IP resolvers in squid sort lookup results by preferred access.
8952 By default squid will use these IP in order and only rotates to
8953 the next listed when the most preffered fails.
8955 Some load balancing servers based on round robin DNS have been
8956 found not to preserve user session state across requests
8957 to different IP addresses.
8959 Enabling this directive Squid rotates IP's per request.
8962 NAME: pipeline_prefetch
8963 TYPE: pipelinePrefetch
8964 LOC: Config.pipeline_max_prefetch
8966 DEFAULT_DOC: Do not pre-parse pipelined requests.
8968 HTTP clients may send a pipeline of 1+N requests to Squid using a
8969 single connection, without waiting for Squid to respond to the first
8970 of those requests. This option limits the number of concurrent
8971 requests Squid will try to handle in parallel. If set to N, Squid
8972 will try to receive and process up to 1+N requests on the same
8973 connection concurrently.
8975 Defaults to 0 (off) for bandwidth management and access logging
8978 NOTE: pipelining requires persistent connections to clients.
8980 WARNING: pipelining breaks NTLM and Negotiate/Kerberos authentication.
8983 NAME: high_response_time_warning
8986 LOC: Config.warnings.high_rptm
8988 DEFAULT_DOC: disabled.
8990 If the one-minute median response time exceeds this value,
8991 Squid prints a WARNING with debug level 0 to get the
8992 administrators attention. The value is in milliseconds.
8995 NAME: high_page_fault_warning
8997 LOC: Config.warnings.high_pf
8999 DEFAULT_DOC: disabled.
9001 If the one-minute average page fault rate exceeds this
9002 value, Squid prints a WARNING with debug level 0 to get
9003 the administrators attention. The value is in page faults
9007 NAME: high_memory_warning
9009 LOC: Config.warnings.high_memory
9010 IFDEF: HAVE_MSTATS&&HAVE_GNUMALLOC_H
9012 DEFAULT_DOC: disabled.
9014 If the memory usage (as determined by gnumalloc, if available and used)
9015 exceeds this amount, Squid prints a WARNING with debug level 0 to get
9016 the administrators attention.
9018 # TODO: link high_memory_warning to mempools?
9020 NAME: sleep_after_fork
9021 COMMENT: (microseconds)
9023 LOC: Config.sleep_after_fork
9026 When this is set to a non-zero value, the main Squid process
9027 sleeps the specified number of microseconds after a fork()
9028 system call. This sleep may help the situation where your
9029 system reports fork() failures due to lack of (virtual)
9030 memory. Note, however, if you have a lot of child
9031 processes, these sleep delays will add up and your
9032 Squid will not service requests for some amount of time
9033 until all the child processes have been started.
9034 On Windows value less then 1000 (1 milliseconds) are
9038 NAME: windows_ipaddrchangemonitor
9039 IFDEF: _SQUID_WINDOWS_
9043 LOC: Config.onoff.WIN32_IpAddrChangeMonitor
9045 On Windows Squid by default will monitor IP address changes and will
9046 reconfigure itself after any detected event. This is very useful for
9047 proxies connected to internet with dial-up interfaces.
9048 In some cases (a Proxy server acting as VPN gateway is one) it could be
9049 desiderable to disable this behaviour setting this to 'off'.
9050 Note: after changing this, Squid service must be restarted.
9055 IFDEF: USE_SQUID_EUI
9057 LOC: Eui::TheConfig.euiLookup
9059 Whether to lookup the EUI or MAC address of a connected client.
9062 NAME: max_filedescriptors max_filedesc
9065 DEFAULT_DOC: Use operating system limits set by ulimit.
9066 LOC: Config.max_filedescriptors
9068 Reduce the maximum number of filedescriptors supported below
9069 the usual operating system defaults.
9071 Remove from squid.conf to inherit the current ulimit setting.
9073 Note: Changing this requires a restart of Squid. Also
9074 not all I/O types supports large values (eg on Windows).
9081 DEFAULT_DOC: SMP support disabled.
9083 Number of main Squid processes or "workers" to fork and maintain.
9084 0: "no daemon" mode, like running "squid -N ..."
9085 1: "no SMP" mode, start one main Squid process daemon (default)
9086 N: start N main Squid process daemons (i.e., SMP mode)
9088 In SMP mode, each worker does nearly all what a single Squid daemon
9089 does (e.g., listen on http_port and forward HTTP requests).
9092 NAME: cpu_affinity_map
9093 TYPE: CpuAffinityMap
9094 LOC: Config.cpuAffinityMap
9096 DEFAULT_DOC: Let operating system decide.
9098 Usage: cpu_affinity_map process_numbers=P1,P2,... cores=C1,C2,...
9100 Sets 1:1 mapping between Squid processes and CPU cores. For example,
9102 cpu_affinity_map process_numbers=1,2,3,4 cores=1,3,5,7
9104 affects processes 1 through 4 only and places them on the first
9105 four even cores, starting with core #1.
9107 CPU cores are numbered starting from 1. Requires support for
9108 sched_getaffinity(2) and sched_setaffinity(2) system calls.
9110 Multiple cpu_affinity_map options are merged.
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