2 # SQUID Web Proxy Cache http://www.squid-cache.org/
3 # ----------------------------------------------------------
5 # Squid is the result of efforts by numerous individuals from
6 # the Internet community; see the CONTRIBUTORS file for full
7 # details. Many organizations have provided support for Squid's
8 # development; see the SPONSORS file for full details. Squid is
9 # Copyrighted (C) 2000 by the Regents of the University of
10 # California; see the COPYRIGHT file for full details. Squid
11 # incorporates software developed and/or copyrighted by other
12 # sources; see the CREDITS file for full details.
14 # This program is free software; you can redistribute it and/or modify
15 # it under the terms of the GNU General Public License as published by
16 # the Free Software Foundation; either version 2 of the License, or
17 # (at your option) any later version.
19 # This program is distributed in the hope that it will be useful,
20 # but WITHOUT ANY WARRANTY; without even the implied warranty of
21 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 # GNU General Public License for more details.
24 # You should have received a copy of the GNU General Public License
25 # along with this program; if not, write to the Free Software
26 # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
31 ----------------------------
33 This is the documentation for the Squid configuration file.
34 This documentation can also be found online at:
35 http://www.squid-cache.org/Doc/config/
37 You may wish to look at the Squid home page and wiki for the
38 FAQ and other documentation:
39 http://www.squid-cache.org/
40 http://wiki.squid-cache.org/SquidFaq
41 http://wiki.squid-cache.org/ConfigExamples
43 This documentation shows what the defaults for various directives
44 happen to be. If you don't need to change the default, you should
45 leave the line out of your squid.conf in most cases.
47 In some cases "none" refers to no default setting at all,
48 while in other cases it refers to the value of the option
49 - the comments for that keyword indicate if this is the case.
54 Configuration options can be included using the "include" directive.
55 Include takes a list of files to include. Quoting and wildcards are
60 include /path/to/included/file/squid.acl.config
62 Includes can be nested up to a hard-coded depth of 16 levels.
63 This arbitrary restriction is to prevent recursive include references
64 from causing Squid entering an infinite loop whilst trying to load
67 Values with byte units
69 Squid accepts size units on some size related directives. All
70 such directives are documented with a default value displaying
73 Units accepted by Squid are:
75 KB - Kilobyte (1024 bytes)
79 Values with spaces, quotes, and other special characters
81 Squid supports directive parameters with spaces, quotes, and other
82 special characters. Surround such parameters with "double quotes". Use
83 the configuration_includes_quoted_values directive to enable or
86 Squid supports reading configuration option parameters from external
87 files using the syntax:
88 parameters("/path/filename")
90 acl whitelist dstdomain parameters("/etc/squid/whitelist.txt")
92 Conditional configuration
94 If-statements can be used to make configuration directives
98 ... regular configuration directives ...
100 ... regular configuration directives ...]
103 The else part is optional. The keywords "if", "else", and "endif"
104 must be typed on their own lines, as if they were regular
105 configuration directives.
107 NOTE: An else-if condition is not supported.
109 These individual conditions types are supported:
112 Always evaluates to true.
114 Always evaluates to false.
115 <integer> = <integer>
116 Equality comparison of two integer numbers.
121 The following SMP-related preprocessor macros can be used.
123 ${process_name} expands to the current Squid process "name"
124 (e.g., squid1, squid2, or cache1).
126 ${process_number} expands to the current Squid process
127 identifier, which is an integer number (e.g., 1, 2, 3) unique
128 across all Squid processes of the current service instance.
130 ${service_name} expands into the current Squid service instance
131 name identifier which is provided by -n on the command line.
135 # options still not yet ported from 2.7 to 3.x
136 NAME: broken_vary_encoding
139 This option is not yet supported by Squid-3.
145 This option is not yet supported by Squid-3.
151 This option is not yet supported by Squid-3.
154 NAME: external_refresh_check
157 This option is not yet supported by Squid-3.
160 NAME: location_rewrite_program location_rewrite_access location_rewrite_children location_rewrite_concurrency
163 This option is not yet supported by Squid-3.
166 NAME: refresh_stale_hit
169 This option is not yet supported by Squid-3.
172 # Options Removed in 3.3
173 NAME: ignore_ims_on_miss
176 Remove this line. The HTTP/1.1 feature is now configured by 'cache_miss_revalidate'.
179 # Options Removed in 3.2
180 NAME: ignore_expect_100
183 Remove this line. The HTTP/1.1 feature is now fully supported by default.
186 NAME: dns_v4_fallback
189 Remove this line. Squid performs a 'Happy Eyeballs' algorithm, the 'fallback' algorithm is no longer relevant.
195 Remove this line. Configure FTP page display using the CSS controls in errorpages.css instead.
198 NAME: maximum_single_addr_tries
201 Replaced by connect_retries. The behaviour has changed, please read the documentation before altering.
207 Remove this line. The feature is supported by default in storage types where update is implemented.
210 NAME: url_rewrite_concurrency
213 Remove this line. Set the 'concurrency=' option of url_rewrite_children instead.
216 # Options Removed in 3.1
220 Remove this line. DNS is no longer tested on startup.
223 NAME: extension_methods
226 Remove this line. All valid methods for HTTP are accepted by default.
229 # 2.7 Options Removed/Replaced in 3.2
234 # 2.7 Options Removed/Replaced in 3.1
242 Remove this line. HTTP/1.1 is supported by default.
245 NAME: upgrade_http0.9
248 Remove this line. ICY/1.0 streaming protocol is supported by default.
251 NAME: zph_local zph_mode zph_option zph_parent zph_sibling
254 Alter these entries. Use the qos_flows directive instead.
257 # Options Removed in 3.0
261 Since squid-3.0 replace with request_header_access or reply_header_access
262 depending on whether you wish to match client requests or server replies.
265 NAME: httpd_accel_no_pmtu_disc
268 Since squid-3.0 use the 'disable-pmtu-discovery' flag on http_port instead.
271 NAME: wais_relay_host
274 Replace this line with 'cache_peer' configuration.
277 NAME: wais_relay_port
280 Replace this line with 'cache_peer' configuration.
284 OPTIONS FOR AUTHENTICATION
285 -----------------------------------------------------------------------------
294 This is used to define parameters for the various authentication
295 schemes supported by Squid.
297 format: auth_param scheme parameter [setting]
299 The order in which authentication schemes are presented to the client is
300 dependent on the order the scheme first appears in config file. IE
301 has a bug (it's not RFC 2617 compliant) in that it will use the basic
302 scheme if basic is the first entry presented, even if more secure
303 schemes are presented. For now use the order in the recommended
304 settings section below. If other browsers have difficulties (don't
305 recognize the schemes offered even if you are using basic) either
306 put basic first, or disable the other schemes (by commenting out their
309 Once an authentication scheme is fully configured, it can only be
310 shutdown by shutting squid down and restarting. Changes can be made on
311 the fly and activated with a reconfigure. I.E. You can change to a
312 different helper, but not unconfigure the helper completely.
314 Please note that while this directive defines how Squid processes
315 authentication it does not automatically activate authentication.
316 To use authentication you must in addition make use of ACLs based
317 on login name in http_access (proxy_auth, proxy_auth_regex or
318 external with %LOGIN used in the format tag). The browser will be
319 challenged for authentication on the first such acl encountered
320 in http_access processing and will also be re-challenged for new
321 login credentials if the request is being denied by a proxy_auth
324 WARNING: authentication can't be used in a transparently intercepting
325 proxy as the client then thinks it is talking to an origin server and
326 not the proxy. This is a limitation of bending the TCP/IP protocol to
327 transparently intercepting port 80, not a limitation in Squid.
328 Ports flagged 'transparent', 'intercept', or 'tproxy' have
329 authentication disabled.
331 === Parameters common to all schemes. ===
334 Specifies the command for the external authenticator.
336 By default, each authentication scheme is not used unless a
337 program is specified.
339 See http://wiki.squid-cache.org/Features/AddonHelpers for
340 more details on helper operations and creating your own.
343 Specifies a string to be append to request line format for
344 the authentication helper. "Quoted" format values may contain
345 spaces and logformat %macros. In theory, any logformat %macro
346 can be used. In practice, a %macro expands as a dash (-) if
347 the helper request is sent before the required macro
348 information is available to Squid.
350 By default, Squid uses request formats provided in
351 scheme-specific examples below (search for %credentials).
353 The expanded key_extras value is added to the Squid credentials
354 cache and, hence, will affect authentication. It can be used to
355 autenticate different users with identical user names (e.g.,
356 when user authentication depends on http_port).
358 Avoid adding frequently changing information to key_extras. For
359 example, if you add user source IP, and it changes frequently
360 in your environment, then max_user_ip ACL is going to treat
361 every user+IP combination as a unique "user", breaking the ACL
362 and wasting a lot of memory on those user records. It will also
363 force users to authenticate from scratch whenever their IP
367 Specifies the protection scope (aka realm name) which is to be
368 reported to the client for the authentication scheme. It is
369 commonly part of the text the user will see when prompted for
370 their username and password.
372 For Basic the default is "Squid proxy-caching web server".
373 For Digest there is no default, this parameter is mandatory.
374 For NTLM and Negotiate this parameter is ignored.
376 "children" numberofchildren [startup=N] [idle=N] [concurrency=N]
378 The maximum number of authenticator processes to spawn. If
379 you start too few Squid will have to wait for them to process
380 a backlog of credential verifications, slowing it down. When
381 password verifications are done via a (slow) network you are
382 likely to need lots of authenticator processes.
384 The startup= and idle= options permit some skew in the exact
385 amount run. A minimum of startup=N will begin during startup
386 and reconfigure. Squid will start more in groups of up to
387 idle=N in an attempt to meet traffic needs and to keep idle=N
388 free above those traffic needs up to the maximum.
390 The concurrency= option sets the number of concurrent requests
391 the helper can process. The default of 0 is used for helpers
392 who only supports one request at a time. Setting this to a
393 number greater than 0 changes the protocol used to include a
394 channel ID field first on the request/response line, allowing
395 multiple requests to be sent to the same helper in parallel
396 without waiting for the response.
398 Concurrency must not be set unless it's known the helper
399 supports the input format with channel-ID fields.
401 NOTE: NTLM and Negotiate schemes do not support concurrency
402 in the Squid code module even though some helpers can.
405 IF HAVE_AUTH_MODULE_BASIC
406 === Basic authentication parameters ===
409 HTTP uses iso-latin-1 as character set, while some
410 authentication backends such as LDAP expects UTF-8. If this is
411 set to on Squid will translate the HTTP iso-latin-1 charset to
412 UTF-8 before sending the username and password to the helper.
414 "credentialsttl" timetolive
415 Specifies how long squid assumes an externally validated
416 username:password pair is valid for - in other words how
417 often the helper program is called for that user. Set this
418 low to force revalidation with short lived passwords.
420 NOTE: setting this high does not impact your susceptibility
421 to replay attacks unless you are using an one-time password
422 system (such as SecureID). If you are using such a system,
423 you will be vulnerable to replay attacks unless you also
424 use the max_user_ip ACL in an http_access rule.
426 "casesensitive" on|off
427 Specifies if usernames are case sensitive. Most user databases
428 are case insensitive allowing the same username to be spelled
429 using both lower and upper case letters, but some are case
430 sensitive. This makes a big difference for user_max_ip ACL
431 processing and similar.
434 IF HAVE_AUTH_MODULE_DIGEST
435 === Digest authentication parameters ===
438 HTTP uses iso-latin-1 as character set, while some
439 authentication backends such as LDAP expects UTF-8. If this is
440 set to on Squid will translate the HTTP iso-latin-1 charset to
441 UTF-8 before sending the username and password to the helper.
443 "nonce_garbage_interval" timeinterval
444 Specifies the interval that nonces that have been issued
445 to client_agent's are checked for validity.
447 "nonce_max_duration" timeinterval
448 Specifies the maximum length of time a given nonce will be
451 "nonce_max_count" number
452 Specifies the maximum number of times a given nonce can be
455 "nonce_strictness" on|off
456 Determines if squid requires strict increment-by-1 behavior
457 for nonce counts, or just incrementing (off - for use when
458 user agents generate nonce counts that occasionally miss 1
459 (ie, 1,2,4,6)). Default off.
461 "check_nonce_count" on|off
462 This directive if set to off can disable the nonce count check
463 completely to work around buggy digest qop implementations in
464 certain mainstream browser versions. Default on to check the
465 nonce count to protect from authentication replay attacks.
467 "post_workaround" on|off
468 This is a workaround to certain buggy browsers who send an
469 incorrect request digest in POST requests when reusing the
470 same nonce as acquired earlier on a GET request.
473 IF HAVE_AUTH_MODULE_NEGOTIATE
474 === Negotiate authentication parameters ===
477 If you experience problems with PUT/POST requests when using
478 the this authentication scheme then you can try setting this
479 to off. This will cause Squid to forcibly close the connection
480 on the initial request where the browser asks which schemes
481 are supported by the proxy.
484 IF HAVE_AUTH_MODULE_NTLM
485 === NTLM authentication parameters ===
488 If you experience problems with PUT/POST requests when using
489 the this authentication scheme then you can try setting this
490 to off. This will cause Squid to forcibly close the connection
491 on the initial request where the browser asks which schemes
492 are supported by the proxy.
495 === Example Configuration ===
497 This configuration displays the recommended authentication scheme
498 order from most to least secure with recommended minimum configuration
499 settings for each scheme:
501 #auth_param negotiate program <uncomment and complete this line to activate>
502 #auth_param negotiate children 20 startup=0 idle=1
503 #auth_param negotiate keep_alive on
505 #auth_param digest program <uncomment and complete this line to activate>
506 #auth_param digest children 20 startup=0 idle=1
507 #auth_param digest realm Squid proxy-caching web server
508 #auth_param digest nonce_garbage_interval 5 minutes
509 #auth_param digest nonce_max_duration 30 minutes
510 #auth_param digest nonce_max_count 50
512 #auth_param ntlm program <uncomment and complete this line to activate>
513 #auth_param ntlm children 20 startup=0 idle=1
514 #auth_param ntlm keep_alive on
516 #auth_param basic program <uncomment and complete this line>
517 #auth_param basic children 5 startup=5 idle=1
518 #auth_param basic realm Squid proxy-caching web server
519 #auth_param basic credentialsttl 2 hours
522 NAME: authenticate_cache_garbage_interval
525 LOC: Config.authenticateGCInterval
527 The time period between garbage collection across the username cache.
528 This is a trade-off between memory utilization (long intervals - say
529 2 days) and CPU (short intervals - say 1 minute). Only change if you
533 NAME: authenticate_ttl
536 LOC: Config.authenticateTTL
538 The time a user & their credentials stay in the logged in
539 user cache since their last request. When the garbage
540 interval passes, all user credentials that have passed their
541 TTL are removed from memory.
544 NAME: authenticate_ip_ttl
546 LOC: Config.authenticateIpTTL
549 If you use proxy authentication and the 'max_user_ip' ACL,
550 this directive controls how long Squid remembers the IP
551 addresses associated with each user. Use a small value
552 (e.g., 60 seconds) if your users might change addresses
553 quickly, as is the case with dialup. You might be safe
554 using a larger value (e.g., 2 hours) in a corporate LAN
555 environment with relatively static address assignments.
560 -----------------------------------------------------------------------------
563 NAME: external_acl_type
564 TYPE: externalAclHelper
565 LOC: Config.externalAclHelperList
568 This option defines external acl classes using a helper program
569 to look up the status
571 external_acl_type name [options] FORMAT.. /path/to/helper [helper arguments..]
575 ttl=n TTL in seconds for cached results (defaults to 3600
578 TTL for cached negative lookups (default same
581 Maximum number of acl helper processes spawned to service
582 external acl lookups of this type. (default 20)
584 Minimum number of acl helper processes to spawn during
585 startup and reconfigure to service external acl lookups
586 of this type. (default 0)
588 Number of acl helper processes to keep ahead of traffic
589 loads. Squid will spawn this many at once whenever load
590 rises above the capabilities of existing processes.
591 Up to the value of children-max. (default 1)
592 concurrency=n concurrency level per process. Only used with helpers
593 capable of processing more than one query at a time.
594 cache=n limit the result cache size, default is 262144.
595 grace=n Percentage remaining of TTL where a refresh of a
596 cached entry should be initiated without needing to
597 wait for a new reply. (default is for no grace period)
598 protocol=2.5 Compatibility mode for Squid-2.5 external acl helpers
599 ipv4 / ipv6 IP protocol used to communicate with this helper.
600 The default is to auto-detect IPv6 and use it when available.
602 FORMAT specifications
604 %LOGIN Authenticated user login name
605 %EXT_USER Username from previous external acl
606 %EXT_LOG Log details from previous external acl
607 %EXT_TAG Tag from previous external acl
608 %IDENT Ident user name
610 %SRCPORT Client source port
613 %PROTO Requested URL scheme
615 %PATH Requested URL path
616 %METHOD Request method
617 %MYADDR Squid interface address
618 %MYPORT Squid http_port number
619 %PATH Requested URL-path (including query-string if any)
620 %USER_CERT SSL User certificate in PEM format
621 %USER_CERTCHAIN SSL User certificate chain in PEM format
622 %USER_CERT_xx SSL User certificate subject attribute xx
623 %USER_CA_xx SSL User certificate issuer attribute xx
625 %>{Header} HTTP request header "Header"
627 HTTP request header "Hdr" list member "member"
629 HTTP request header list member using ; as
630 list separator. ; can be any non-alphanumeric
633 %<{Header} HTTP reply header "Header"
635 HTTP reply header "Hdr" list member "member"
637 HTTP reply header list member using ; as
638 list separator. ; can be any non-alphanumeric
641 %ACL The name of the ACL being tested.
642 %DATA The ACL arguments. If not used then any arguments
643 is automatically added at the end of the line
645 NOTE: this will encode the arguments as one token,
646 whereas the default will pass each separately.
648 %% The percent sign. Useful for helpers which need
649 an unchanging input format.
652 General request syntax:
654 [channel-ID] FORMAT-values [acl-values ...]
657 FORMAT-values consists of transaction details expanded with
658 whitespace separation per the config file FORMAT specification
659 using the FORMAT macros listed above.
661 acl-values consists of any string specified in the referencing
662 config 'acl ... external' line. see the "acl external" directive.
664 Request values sent to the helper are URL escaped to protect
665 each value in requests against whitespaces.
667 If using protocol=2.5 then the request sent to the helper is not
668 URL escaped to protect against whitespace.
670 NOTE: protocol=3.0 is deprecated as no longer necessary.
672 When using the concurrency= option the protocol is changed by
673 introducing a query channel tag in front of the request/response.
674 The query channel tag is a number between 0 and concurrency-1.
675 This value must be echoed back unchanged to Squid as the first part
676 of the response relating to its request.
679 The helper receives lines expanded per the above format specification
680 and for each input line returns 1 line starting with OK/ERR/BH result
681 code and optionally followed by additional keywords with more details.
684 General result syntax:
686 [channel-ID] result keyword=value ...
688 Result consists of one of the codes:
691 the ACL test produced a match.
694 the ACL test does not produce a match.
697 An internal error occurred in the helper, preventing
698 a result being identified.
700 The meaning of 'a match' is determined by your squid.conf
701 access control configuration. See the Squid wiki for details.
705 user= The users name (login)
707 password= The users password (for login= cache_peer option)
709 message= Message describing the reason for this response.
710 Available as %o in error pages.
711 Useful on (ERR and BH results).
713 tag= Apply a tag to a request. Only sets a tag once,
714 does not alter existing tags.
716 log= String to be logged in access.log. Available as
717 %ea in logformat specifications.
719 clt_conn_tag= Associates a TAG with the client TCP connection.
720 Please see url_rewrite_program related documentation for
723 Any keywords may be sent on any response whether OK, ERR or BH.
725 All response keyword values need to be a single token with URL
726 escaping, or enclosed in double quotes (") and escaped using \ on
727 any double quotes or \ characters within the value. The wrapping
728 double quotes are removed before the value is interpreted by Squid.
729 \r and \n are also replace by CR and LF.
731 Some example key values:
735 user="J. \"Bob\" Smith"
742 DEFAULT: ssl::certHasExpired ssl_error X509_V_ERR_CERT_HAS_EXPIRED
743 DEFAULT: ssl::certNotYetValid ssl_error X509_V_ERR_CERT_NOT_YET_VALID
744 DEFAULT: ssl::certDomainMismatch ssl_error SQUID_X509_V_ERR_DOMAIN_MISMATCH
745 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
746 DEFAULT: ssl::certSelfSigned ssl_error X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT
749 DEFAULT: manager url_regex -i ^cache_object:// +i ^https?://[^/]+/squid-internal-mgr/
750 DEFAULT: localhost src 127.0.0.1/32 ::1
751 DEFAULT: to_localhost dst 127.0.0.0/8 0.0.0.0/32 ::1
752 DEFAULT_DOC: ACLs all, manager, localhost, and to_localhost are predefined.
754 Defining an Access List
756 Every access list definition must begin with an aclname and acltype,
757 followed by either type-specific arguments or a quoted filename that
760 acl aclname acltype argument ...
761 acl aclname acltype "file" ...
763 When using "file", the file should contain one item per line.
765 Some acl types supports options which changes their default behaviour.
766 The available options are:
768 -i,+i By default, regular expressions are CASE-SENSITIVE. To make them
769 case-insensitive, use the -i option. To return case-sensitive
770 use the +i option between patterns, or make a new ACL line
773 -n Disable lookups and address type conversions. If lookup or
774 conversion is required because the parameter type (IP or
775 domain name) does not match the message address type (domain
776 name or IP), then the ACL would immediately declare a mismatch
777 without any warnings or lookups.
779 -- Used to stop processing all options, in the case the first acl
780 value has '-' character as first character (for example the '-'
781 is a valid domain name)
783 Some acl types require suspending the current request in order
784 to access some external data source.
785 Those which do are marked with the tag [slow], those which
786 don't are marked as [fast].
787 See http://wiki.squid-cache.org/SquidFaq/SquidAcl
788 for further information
790 ***** ACL TYPES AVAILABLE *****
792 acl aclname src ip-address/mask ... # clients IP address [fast]
793 acl aclname src addr1-addr2/mask ... # range of addresses [fast]
794 acl aclname dst [-n] ip-address/mask ... # URL host's IP address [slow]
795 acl aclname localip ip-address/mask ... # IP address the client connected to [fast]
797 acl aclname arp mac-address ... (xx:xx:xx:xx:xx:xx notation)
798 # The arp ACL requires the special configure option --enable-arp-acl.
799 # Furthermore, the ARP ACL code is not portable to all operating systems.
800 # It works on Linux, Solaris, Windows, FreeBSD, and some
801 # other *BSD variants.
804 # NOTE: Squid can only determine the MAC address for clients that are on
805 # the same subnet. If the client is on a different subnet,
806 # then Squid cannot find out its MAC address.
808 acl aclname srcdomain .foo.com ...
809 # reverse lookup, from client IP [slow]
810 acl aclname dstdomain [-n] .foo.com ...
811 # Destination server from URL [fast]
812 acl aclname srcdom_regex [-i] \.foo\.com ...
813 # regex matching client name [slow]
814 acl aclname dstdom_regex [-n] [-i] \.foo\.com ...
815 # regex matching server [fast]
817 # For dstdomain and dstdom_regex a reverse lookup is tried if a IP
818 # based URL is used and no match is found. The name "none" is used
819 # if the reverse lookup fails.
821 acl aclname src_as number ...
822 acl aclname dst_as number ...
824 # Except for access control, AS numbers can be used for
825 # routing of requests to specific caches. Here's an
826 # example for routing all requests for AS#1241 and only
827 # those to mycache.mydomain.net:
828 # acl asexample dst_as 1241
829 # cache_peer_access mycache.mydomain.net allow asexample
830 # cache_peer_access mycache_mydomain.net deny all
832 acl aclname peername myPeer ...
834 # match against a named cache_peer entry
835 # set unique name= on cache_peer lines for reliable use.
837 acl aclname time [day-abbrevs] [h1:m1-h2:m2]
847 # h1:m1 must be less than h2:m2
849 acl aclname url_regex [-i] ^http:// ...
850 # regex matching on whole URL [fast]
851 acl aclname urllogin [-i] [^a-zA-Z0-9] ...
852 # regex matching on URL login field
853 acl aclname urlpath_regex [-i] \.gif$ ...
854 # regex matching on URL path [fast]
856 acl aclname port 80 70 21 0-1024... # destination TCP port [fast]
858 acl aclname localport 3128 ... # TCP port the client connected to [fast]
859 # NP: for interception mode this is usually '80'
861 acl aclname myportname 3128 ... # http(s)_port name [fast]
863 acl aclname proto HTTP FTP ... # request protocol [fast]
865 acl aclname method GET POST ... # HTTP request method [fast]
867 acl aclname http_status 200 301 500- 400-403 ...
868 # status code in reply [fast]
870 acl aclname browser [-i] regexp ...
871 # pattern match on User-Agent header (see also req_header below) [fast]
873 acl aclname referer_regex [-i] regexp ...
874 # pattern match on Referer header [fast]
875 # Referer is highly unreliable, so use with care
877 acl aclname ident username ...
878 acl aclname ident_regex [-i] pattern ...
879 # string match on ident output [slow]
880 # use REQUIRED to accept any non-null ident.
882 acl aclname proxy_auth [-i] username ...
883 acl aclname proxy_auth_regex [-i] pattern ...
884 # perform http authentication challenge to the client and match against
885 # supplied credentials [slow]
887 # takes a list of allowed usernames.
888 # use REQUIRED to accept any valid username.
890 # Will use proxy authentication in forward-proxy scenarios, and plain
891 # http authenticaiton in reverse-proxy scenarios
893 # NOTE: when a Proxy-Authentication header is sent but it is not
894 # needed during ACL checking the username is NOT logged
897 # NOTE: proxy_auth requires a EXTERNAL authentication program
898 # to check username/password combinations (see
899 # auth_param directive).
901 # NOTE: proxy_auth can't be used in a transparent/intercepting proxy
902 # as the browser needs to be configured for using a proxy in order
903 # to respond to proxy authentication.
905 acl aclname snmp_community string ...
906 # A community string to limit access to your SNMP Agent [fast]
909 # acl snmppublic snmp_community public
911 acl aclname maxconn number
912 # This will be matched when the client's IP address has
913 # more than <number> TCP connections established. [fast]
914 # NOTE: This only measures direct TCP links so X-Forwarded-For
915 # indirect clients are not counted.
917 acl aclname max_user_ip [-s] number
918 # This will be matched when the user attempts to log in from more
919 # than <number> different ip addresses. The authenticate_ip_ttl
920 # parameter controls the timeout on the ip entries. [fast]
921 # If -s is specified the limit is strict, denying browsing
922 # from any further IP addresses until the ttl has expired. Without
923 # -s Squid will just annoy the user by "randomly" denying requests.
924 # (the counter is reset each time the limit is reached and a
926 # NOTE: in acceleration mode or where there is mesh of child proxies,
927 # clients may appear to come from multiple addresses if they are
928 # going through proxy farms, so a limit of 1 may cause user problems.
930 acl aclname random probability
931 # Pseudo-randomly match requests. Based on the probability given.
932 # Probability may be written as a decimal (0.333), fraction (1/3)
933 # or ratio of matches:non-matches (3:5).
935 acl aclname req_mime_type [-i] mime-type ...
936 # regex match against the mime type of the request generated
937 # by the client. Can be used to detect file upload or some
938 # types HTTP tunneling requests [fast]
939 # NOTE: This does NOT match the reply. You cannot use this
940 # to match the returned file type.
942 acl aclname req_header header-name [-i] any\.regex\.here
943 # regex match against any of the known request headers. May be
944 # thought of as a superset of "browser", "referer" and "mime-type"
947 acl aclname rep_mime_type [-i] mime-type ...
948 # regex match against the mime type of the reply received by
949 # squid. Can be used to detect file download or some
950 # types HTTP tunneling requests. [fast]
951 # NOTE: This has no effect in http_access rules. It only has
952 # effect in rules that affect the reply data stream such as
955 acl aclname rep_header header-name [-i] any\.regex\.here
956 # regex match against any of the known reply headers. May be
957 # thought of as a superset of "browser", "referer" and "mime-type"
960 acl aclname external class_name [arguments...]
961 # external ACL lookup via a helper class defined by the
962 # external_acl_type directive [slow]
964 acl aclname user_cert attribute values...
965 # match against attributes in a user SSL certificate
966 # attribute is one of DN/C/O/CN/L/ST [fast]
968 acl aclname ca_cert attribute values...
969 # match against attributes a users issuing CA SSL certificate
970 # attribute is one of DN/C/O/CN/L/ST [fast]
972 acl aclname ext_user username ...
973 acl aclname ext_user_regex [-i] pattern ...
974 # string match on username returned by external acl helper [slow]
975 # use REQUIRED to accept any non-null user name.
977 acl aclname tag tagvalue ...
978 # string match on tag returned by external acl helper [slow]
980 acl aclname hier_code codename ...
981 # string match against squid hierarchy code(s); [fast]
982 # e.g., DIRECT, PARENT_HIT, NONE, etc.
984 # NOTE: This has no effect in http_access rules. It only has
985 # effect in rules that affect the reply data stream such as
988 acl aclname note name [value ...]
989 # match transaction annotation [fast]
990 # Without values, matches any annotation with a given name.
991 # With value(s), matches any annotation with a given name that
992 # also has one of the given values.
993 # Names and values are compared using a string equality test.
994 # Annotation sources include note and adaptation_meta directives
995 # as well as helper and eCAP responses.
997 acl aclname adaptation_service service ...
998 # Matches the name of any icap_service, ecap_service,
999 # adaptation_service_set, or adaptation_service_chain that Squid
1000 # has used (or attempted to use) for the master transaction.
1001 # This ACL must be defined after the corresponding adaptation
1002 # service is named in squid.conf. This ACL is usable with
1003 # adaptation_meta because it starts matching immediately after
1004 # the service has been selected for adaptation.
1007 acl aclname ssl_error errorname
1008 # match against SSL certificate validation error [fast]
1010 # For valid error names see in @DEFAULT_ERROR_DIR@/templates/error-details.txt
1013 # The following can be used as shortcuts for certificate properties:
1014 # [ssl::]certHasExpired: the "not after" field is in the past
1015 # [ssl::]certNotYetValid: the "not before" field is in the future
1016 # [ssl::]certUntrusted: The certificate issuer is not to be trusted.
1017 # [ssl::]certSelfSigned: The certificate is self signed.
1018 # [ssl::]certDomainMismatch: The certificate CN domain does not
1019 # match the name the name of the host we are connecting to.
1021 # The ssl::certHasExpired, ssl::certNotYetValid, ssl::certDomainMismatch,
1022 # ssl::certUntrusted, and ssl::certSelfSigned can also be used as
1023 # predefined ACLs, just like the 'all' ACL.
1025 # NOTE: The ssl_error ACL is only supported with sslproxy_cert_error,
1026 # sslproxy_cert_sign, and sslproxy_cert_adapt options.
1028 acl aclname server_cert_fingerprint [-sha1] fingerprint
1029 # match against server SSL certificate fingerprint [fast]
1031 # The fingerprint is the digest of the DER encoded version
1032 # of the whole certificate. The user should use the form: XX:XX:...
1033 # Optional argument specifies the digest algorithm to use.
1034 # The SHA1 digest algorithm is the default and is currently
1035 # the only algorithm supported (-sha1).
1037 acl aclname any-of acl1 acl2 ...
1038 # match any one of the acls [fast or slow]
1039 # The first matching ACL stops further ACL evaluation.
1041 # ACLs from multiple any-of lines with the same name are ORed.
1042 # For example, A = (a1 or a2) or (a3 or a4) can be written as
1043 # acl A any-of a1 a2
1044 # acl A any-of a3 a4
1046 # This group ACL is fast if all evaluated ACLs in the group are fast
1047 # and slow otherwise.
1049 acl aclname all-of acl1 acl2 ...
1050 # match all of the acls [fast or slow]
1051 # The first mismatching ACL stops further ACL evaluation.
1053 # ACLs from multiple all-of lines with the same name are ORed.
1054 # For example, B = (b1 and b2) or (b3 and b4) can be written as
1055 # acl B all-of b1 b2
1056 # acl B all-of b3 b4
1058 # This group ACL is fast if all evaluated ACLs in the group are fast
1059 # and slow otherwise.
1062 acl macaddress arp 09:00:2b:23:45:67
1063 acl myexample dst_as 1241
1064 acl password proxy_auth REQUIRED
1065 acl fileupload req_mime_type -i ^multipart/form-data$
1066 acl javascript rep_mime_type -i ^application/x-javascript$
1070 # Recommended minimum configuration:
1073 # Example rule allowing access from your local networks.
1074 # Adapt to list your (internal) IP networks from where browsing
1076 acl localnet src 10.0.0.0/8 # RFC1918 possible internal network
1077 acl localnet src 172.16.0.0/12 # RFC1918 possible internal network
1078 acl localnet src 192.168.0.0/16 # RFC1918 possible internal network
1079 acl localnet src fc00::/7 # RFC 4193 local private network range
1080 acl localnet src fe80::/10 # RFC 4291 link-local (directly plugged) machines
1082 acl SSL_ports port 443
1083 acl Safe_ports port 80 # http
1084 acl Safe_ports port 21 # ftp
1085 acl Safe_ports port 443 # https
1086 acl Safe_ports port 70 # gopher
1087 acl Safe_ports port 210 # wais
1088 acl Safe_ports port 1025-65535 # unregistered ports
1089 acl Safe_ports port 280 # http-mgmt
1090 acl Safe_ports port 488 # gss-http
1091 acl Safe_ports port 591 # filemaker
1092 acl Safe_ports port 777 # multiling http
1093 acl CONNECT method CONNECT
1097 NAME: follow_x_forwarded_for
1099 IFDEF: FOLLOW_X_FORWARDED_FOR
1100 LOC: Config.accessList.followXFF
1101 DEFAULT_IF_NONE: deny all
1102 DEFAULT_DOC: X-Forwarded-For header will be ignored.
1104 Allowing or Denying the X-Forwarded-For header to be followed to
1105 find the original source of a request.
1107 Requests may pass through a chain of several other proxies
1108 before reaching us. The X-Forwarded-For header will contain a
1109 comma-separated list of the IP addresses in the chain, with the
1110 rightmost address being the most recent.
1112 If a request reaches us from a source that is allowed by this
1113 configuration item, then we consult the X-Forwarded-For header
1114 to see where that host received the request from. If the
1115 X-Forwarded-For header contains multiple addresses, we continue
1116 backtracking until we reach an address for which we are not allowed
1117 to follow the X-Forwarded-For header, or until we reach the first
1118 address in the list. For the purpose of ACL used in the
1119 follow_x_forwarded_for directive the src ACL type always matches
1120 the address we are testing and srcdomain matches its rDNS.
1122 The end result of this process is an IP address that we will
1123 refer to as the indirect client address. This address may
1124 be treated as the client address for access control, ICAP, delay
1125 pools and logging, depending on the acl_uses_indirect_client,
1126 icap_uses_indirect_client, delay_pool_uses_indirect_client,
1127 log_uses_indirect_client and tproxy_uses_indirect_client options.
1129 This clause only supports fast acl types.
1130 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1132 SECURITY CONSIDERATIONS:
1134 Any host for which we follow the X-Forwarded-For header
1135 can place incorrect information in the header, and Squid
1136 will use the incorrect information as if it were the
1137 source address of the request. This may enable remote
1138 hosts to bypass any access control restrictions that are
1139 based on the client's source addresses.
1143 acl localhost src 127.0.0.1
1144 acl my_other_proxy srcdomain .proxy.example.com
1145 follow_x_forwarded_for allow localhost
1146 follow_x_forwarded_for allow my_other_proxy
1149 NAME: acl_uses_indirect_client
1152 IFDEF: FOLLOW_X_FORWARDED_FOR
1154 LOC: Config.onoff.acl_uses_indirect_client
1156 Controls whether the indirect client address
1157 (see follow_x_forwarded_for) is used instead of the
1158 direct client address in acl matching.
1160 NOTE: maxconn ACL considers direct TCP links and indirect
1161 clients will always have zero. So no match.
1164 NAME: delay_pool_uses_indirect_client
1167 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_DELAY_POOLS
1169 LOC: Config.onoff.delay_pool_uses_indirect_client
1171 Controls whether the indirect client address
1172 (see follow_x_forwarded_for) is used instead of the
1173 direct client address in delay pools.
1176 NAME: log_uses_indirect_client
1179 IFDEF: FOLLOW_X_FORWARDED_FOR
1181 LOC: Config.onoff.log_uses_indirect_client
1183 Controls whether the indirect client address
1184 (see follow_x_forwarded_for) is used instead of the
1185 direct client address in the access log.
1188 NAME: tproxy_uses_indirect_client
1191 IFDEF: FOLLOW_X_FORWARDED_FOR&&LINUX_NETFILTER
1193 LOC: Config.onoff.tproxy_uses_indirect_client
1195 Controls whether the indirect client address
1196 (see follow_x_forwarded_for) is used instead of the
1197 direct client address when spoofing the outgoing client.
1199 This has no effect on requests arriving in non-tproxy
1202 SECURITY WARNING: Usage of this option is dangerous
1203 and should not be used trivially. Correct configuration
1204 of follow_x_forewarded_for with a limited set of trusted
1205 sources is required to prevent abuse of your proxy.
1208 NAME: spoof_client_ip
1210 LOC: Config.accessList.spoof_client_ip
1212 DEFAULT_DOC: Allow spoofing on all TPROXY traffic.
1214 Control client IP address spoofing of TPROXY traffic based on
1215 defined access lists.
1217 spoof_client_ip allow|deny [!]aclname ...
1219 If there are no "spoof_client_ip" lines present, the default
1220 is to "allow" spoofing of any suitable request.
1222 Note that the cache_peer "no-tproxy" option overrides this ACL.
1224 This clause supports fast acl types.
1225 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1230 LOC: Config.accessList.http
1231 DEFAULT_IF_NONE: deny all
1232 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1234 Allowing or Denying access based on defined access lists
1236 Access to the HTTP port:
1237 http_access allow|deny [!]aclname ...
1239 NOTE on default values:
1241 If there are no "access" lines present, the default is to deny
1244 If none of the "access" lines cause a match, the default is the
1245 opposite of the last line in the list. If the last line was
1246 deny, the default is allow. Conversely, if the last line
1247 is allow, the default will be deny. For these reasons, it is a
1248 good idea to have an "deny all" entry at the end of your access
1249 lists to avoid potential confusion.
1251 This clause supports both fast and slow acl types.
1252 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1257 # Recommended minimum Access Permission configuration:
1259 # Deny requests to certain unsafe ports
1260 http_access deny !Safe_ports
1262 # Deny CONNECT to other than secure SSL ports
1263 http_access deny CONNECT !SSL_ports
1265 # Only allow cachemgr access from localhost
1266 http_access allow localhost manager
1267 http_access deny manager
1269 # We strongly recommend the following be uncommented to protect innocent
1270 # web applications running on the proxy server who think the only
1271 # one who can access services on "localhost" is a local user
1272 #http_access deny to_localhost
1275 # INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS
1278 # Example rule allowing access from your local networks.
1279 # Adapt localnet in the ACL section to list your (internal) IP networks
1280 # from where browsing should be allowed
1281 http_access allow localnet
1282 http_access allow localhost
1284 # And finally deny all other access to this proxy
1285 http_access deny all
1289 NAME: adapted_http_access http_access2
1291 LOC: Config.accessList.adapted_http
1293 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1295 Allowing or Denying access based on defined access lists
1297 Essentially identical to http_access, but runs after redirectors
1298 and ICAP/eCAP adaptation. Allowing access control based on their
1301 If not set then only http_access is used.
1304 NAME: http_reply_access
1306 LOC: Config.accessList.reply
1308 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1310 Allow replies to client requests. This is complementary to http_access.
1312 http_reply_access allow|deny [!] aclname ...
1314 NOTE: if there are no access lines present, the default is to allow
1317 If none of the access lines cause a match the opposite of the
1318 last line will apply. Thus it is good practice to end the rules
1319 with an "allow all" or "deny all" entry.
1321 This clause supports both fast and slow acl types.
1322 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1327 LOC: Config.accessList.icp
1329 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1331 Allowing or Denying access to the ICP port based on defined
1334 icp_access allow|deny [!]aclname ...
1336 NOTE: The default if no icp_access lines are present is to
1337 deny all traffic. This default may cause problems with peers
1340 This clause only supports fast acl types.
1341 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1343 # Allow ICP queries from local networks only
1344 #icp_access allow localnet
1345 #icp_access deny all
1351 LOC: Config.accessList.htcp
1353 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1355 Allowing or Denying access to the HTCP port based on defined
1358 htcp_access allow|deny [!]aclname ...
1360 See also htcp_clr_access for details on access control for
1361 cache purge (CLR) HTCP messages.
1363 NOTE: The default if no htcp_access lines are present is to
1364 deny all traffic. This default may cause problems with peers
1365 using the htcp option.
1367 This clause only supports fast acl types.
1368 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1370 # Allow HTCP queries from local networks only
1371 #htcp_access allow localnet
1372 #htcp_access deny all
1375 NAME: htcp_clr_access
1378 LOC: Config.accessList.htcp_clr
1380 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
1382 Allowing or Denying access to purge content using HTCP based
1383 on defined access lists.
1384 See htcp_access for details on general HTCP access control.
1386 htcp_clr_access allow|deny [!]aclname ...
1388 This clause only supports fast acl types.
1389 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1391 # Allow HTCP CLR requests from trusted peers
1392 acl htcp_clr_peer src 192.0.2.2 2001:DB8::2
1393 htcp_clr_access allow htcp_clr_peer
1394 htcp_clr_access deny all
1399 LOC: Config.accessList.miss
1401 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
1403 Determins whether network access is permitted when satisfying a request.
1406 to force your neighbors to use you as a sibling instead of
1409 acl localclients src 192.0.2.0/24 2001:DB8::a:0/64
1410 miss_access deny !localclients
1411 miss_access allow all
1413 This means only your local clients are allowed to fetch relayed/MISS
1414 replies from the network and all other clients can only fetch cached
1417 The default for this setting allows all clients who passed the
1418 http_access rules to relay via this proxy.
1420 This clause only supports fast acl types.
1421 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1424 NAME: ident_lookup_access
1428 DEFAULT_DOC: Unless rules exist in squid.conf, IDENT is not fetched.
1429 LOC: Ident::TheConfig.identLookup
1431 A list of ACL elements which, if matched, cause an ident
1432 (RFC 931) lookup to be performed for this request. For
1433 example, you might choose to always perform ident lookups
1434 for your main multi-user Unix boxes, but not for your Macs
1435 and PCs. By default, ident lookups are not performed for
1438 To enable ident lookups for specific client addresses, you
1439 can follow this example:
1441 acl ident_aware_hosts src 198.168.1.0/24
1442 ident_lookup_access allow ident_aware_hosts
1443 ident_lookup_access deny all
1445 Only src type ACL checks are fully supported. A srcdomain
1446 ACL might work at times, but it will not always provide
1449 This clause only supports fast acl types.
1450 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1453 NAME: reply_body_max_size
1454 COMMENT: size [acl acl...]
1457 DEFAULT_DOC: No limit is applied.
1458 LOC: Config.ReplyBodySize
1460 This option specifies the maximum size of a reply body. It can be
1461 used to prevent users from downloading very large files, such as
1462 MP3's and movies. When the reply headers are received, the
1463 reply_body_max_size lines are processed, and the first line where
1464 all (if any) listed ACLs are true is used as the maximum body size
1467 This size is checked twice. First when we get the reply headers,
1468 we check the content-length value. If the content length value exists
1469 and is larger than the allowed size, the request is denied and the
1470 user receives an error message that says "the request or reply
1471 is too large." If there is no content-length, and the reply
1472 size exceeds this limit, the client's connection is just closed
1473 and they will receive a partial reply.
1475 WARNING: downstream caches probably can not detect a partial reply
1476 if there is no content-length header, so they will cache
1477 partial responses and give them out as hits. You should NOT
1478 use this option if you have downstream caches.
1480 WARNING: A maximum size smaller than the size of squid's error messages
1481 will cause an infinite loop and crash squid. Ensure that the smallest
1482 non-zero value you use is greater that the maximum header size plus
1483 the size of your largest error page.
1485 If you set this parameter none (the default), there will be
1488 Configuration Format is:
1489 reply_body_max_size SIZE UNITS [acl ...]
1491 reply_body_max_size 10 MB
1497 -----------------------------------------------------------------------------
1500 NAME: http_port ascii_port
1505 Usage: port [mode] [options]
1506 hostname:port [mode] [options]
1507 1.2.3.4:port [mode] [options]
1509 The socket addresses where Squid will listen for HTTP client
1510 requests. You may specify multiple socket addresses.
1511 There are three forms: port alone, hostname with port, and
1512 IP address with port. If you specify a hostname or IP
1513 address, Squid binds the socket to that specific
1514 address. Most likely, you do not need to bind to a specific
1515 address, so you can use the port number alone.
1517 If you are running Squid in accelerator mode, you
1518 probably want to listen on port 80 also, or instead.
1520 The -a command line option may be used to specify additional
1521 port(s) where Squid listens for proxy request. Such ports will
1522 be plain proxy ports with no options.
1524 You may specify multiple socket addresses on multiple lines.
1528 intercept Support for IP-Layer interception of
1529 outgoing requests without browser settings.
1530 NP: disables authentication and IPv6 on the port.
1532 tproxy Support Linux TPROXY for spoofing outgoing
1533 connections using the client IP address.
1534 NP: disables authentication and maybe IPv6 on the port.
1536 accel Accelerator / reverse proxy mode
1538 ssl-bump For each CONNECT request allowed by ssl_bump ACLs,
1539 establish secure connection with the client and with
1540 the server, decrypt HTTPS messages as they pass through
1541 Squid, and treat them as unencrypted HTTP messages,
1542 becoming the man-in-the-middle.
1544 The ssl_bump option is required to fully enable
1545 bumping of CONNECT requests.
1547 Omitting the mode flag causes default forward proxy mode to be used.
1550 Accelerator Mode Options:
1552 defaultsite=domainname
1553 What to use for the Host: header if it is not present
1554 in a request. Determines what site (not origin server)
1555 accelerators should consider the default.
1557 no-vhost Disable using HTTP/1.1 Host header for virtual domain support.
1559 protocol= Protocol to reconstruct accelerated and intercepted
1560 requests with. Defaults to HTTP/1.1 for http_port and
1561 HTTPS/1.1 for https_port.
1562 When an unsupported value is configured Squid will
1563 produce a FATAL error.
1564 Values: HTTP or HTTP/1.1, HTTPS or HTTPS/1.1
1566 vport Virtual host port support. Using the http_port number
1567 instead of the port passed on Host: headers.
1569 vport=NN Virtual host port support. Using the specified port
1570 number instead of the port passed on Host: headers.
1573 Act as if this Squid is the origin server.
1574 This currently means generate new Date: and Expires:
1575 headers on HIT instead of adding Age:.
1577 ignore-cc Ignore request Cache-Control headers.
1579 WARNING: This option violates HTTP specifications if
1580 used in non-accelerator setups.
1582 allow-direct Allow direct forwarding in accelerator mode. Normally
1583 accelerated requests are denied direct forwarding as if
1584 never_direct was used.
1586 WARNING: this option opens accelerator mode to security
1587 vulnerabilities usually only affecting in interception
1588 mode. Make sure to protect forwarding with suitable
1589 http_access rules when using this.
1592 SSL Bump Mode Options:
1593 In addition to these options ssl-bump requires TLS/SSL options.
1595 generate-host-certificates[=<on|off>]
1596 Dynamically create SSL server certificates for the
1597 destination hosts of bumped CONNECT requests.When
1598 enabled, the cert and key options are used to sign
1599 generated certificates. Otherwise generated
1600 certificate will be selfsigned.
1601 If there is a CA certificate lifetime of the generated
1602 certificate equals lifetime of the CA certificate. If
1603 generated certificate is selfsigned lifetime is three
1605 This option is enabled by default when ssl-bump is used.
1606 See the ssl-bump option above for more information.
1608 dynamic_cert_mem_cache_size=SIZE
1609 Approximate total RAM size spent on cached generated
1610 certificates. If set to zero, caching is disabled. The
1611 default value is 4MB.
1615 cert= Path to SSL certificate (PEM format).
1617 key= Path to SSL private key file (PEM format)
1618 if not specified, the certificate file is
1619 assumed to be a combined certificate and
1622 version= The version of SSL/TLS supported
1623 1 automatic (default)
1630 cipher= Colon separated list of supported ciphers.
1631 NOTE: some ciphers such as EDH ciphers depend on
1632 additional settings. If those settings are
1633 omitted the ciphers may be silently ignored
1634 by the OpenSSL library.
1636 options= Various SSL implementation options. The most important
1638 NO_SSLv2 Disallow the use of SSLv2
1639 NO_SSLv3 Disallow the use of SSLv3
1640 NO_TLSv1 Disallow the use of TLSv1.0
1641 NO_TLSv1_1 Disallow the use of TLSv1.1
1642 NO_TLSv1_2 Disallow the use of TLSv1.2
1643 SINGLE_DH_USE Always create a new key when using
1644 temporary/ephemeral DH key exchanges
1645 ALL Enable various bug workarounds
1646 suggested as "harmless" by OpenSSL
1647 Be warned that this reduces SSL/TLS
1648 strength to some attacks.
1649 See OpenSSL SSL_CTX_set_options documentation for a
1650 complete list of options.
1652 clientca= File containing the list of CAs to use when
1653 requesting a client certificate.
1655 cafile= File containing additional CA certificates to
1656 use when verifying client certificates. If unset
1657 clientca will be used.
1659 capath= Directory containing additional CA certificates
1660 and CRL lists to use when verifying client certificates.
1662 crlfile= File of additional CRL lists to use when verifying
1663 the client certificate, in addition to CRLs stored in
1664 the capath. Implies VERIFY_CRL flag below.
1666 dhparams= File containing DH parameters for temporary/ephemeral
1667 DH key exchanges. See OpenSSL documentation for details
1668 on how to create this file.
1669 WARNING: EDH ciphers will be silently disabled if this
1672 sslflags= Various flags modifying the use of SSL:
1674 Don't request client certificates
1675 immediately, but wait until acl processing
1676 requires a certificate (not yet implemented).
1678 Don't use the default CA lists built in
1681 Don't allow for session reuse. Each connection
1682 will result in a new SSL session.
1684 Verify CRL lists when accepting client
1687 Verify CRL lists for all certificates in the
1688 client certificate chain.
1690 sslcontext= SSL session ID context identifier.
1694 connection-auth[=on|off]
1695 use connection-auth=off to tell Squid to prevent
1696 forwarding Microsoft connection oriented authentication
1697 (NTLM, Negotiate and Kerberos)
1699 disable-pmtu-discovery=
1700 Control Path-MTU discovery usage:
1701 off lets OS decide on what to do (default).
1702 transparent disable PMTU discovery when transparent
1704 always disable always PMTU discovery.
1706 In many setups of transparently intercepting proxies
1707 Path-MTU discovery can not work on traffic towards the
1708 clients. This is the case when the intercepting device
1709 does not fully track connections and fails to forward
1710 ICMP must fragment messages to the cache server. If you
1711 have such setup and experience that certain clients
1712 sporadically hang or never complete requests set
1713 disable-pmtu-discovery option to 'transparent'.
1715 name= Specifies a internal name for the port. Defaults to
1716 the port specification (port or addr:port)
1718 tcpkeepalive[=idle,interval,timeout]
1719 Enable TCP keepalive probes of idle connections.
1720 In seconds; idle is the initial time before TCP starts
1721 probing the connection, interval how often to probe, and
1722 timeout the time before giving up.
1724 If you run Squid on a dual-homed machine with an internal
1725 and an external interface we recommend you to specify the
1726 internal address:port in http_port. This way Squid will only be
1727 visible on the internal address.
1731 # Squid normally listens to port 3128
1732 http_port @DEFAULT_HTTP_PORT@
1742 Usage: [ip:]port cert=certificate.pem [key=key.pem] [mode] [options...]
1744 The socket address where Squid will listen for client requests made
1745 over TLS or SSL connections. Commonly referred to as HTTPS.
1747 This is most useful for situations where you are running squid in
1748 accelerator mode and you want to do the SSL work at the accelerator level.
1750 You may specify multiple socket addresses on multiple lines,
1751 each with their own SSL certificate and/or options.
1755 accel Accelerator / reverse proxy mode
1757 intercept Support for IP-Layer interception of
1758 outgoing requests without browser settings.
1759 NP: disables authentication and IPv6 on the port.
1761 tproxy Support Linux TPROXY for spoofing outgoing
1762 connections using the client IP address.
1763 NP: disables authentication and maybe IPv6 on the port.
1765 ssl-bump For each intercepted connection allowed by ssl_bump
1766 ACLs, establish a secure connection with the client and with
1767 the server, decrypt HTTPS messages as they pass through
1768 Squid, and treat them as unencrypted HTTP messages,
1769 becoming the man-in-the-middle.
1771 An "ssl_bump server-first" match is required to
1772 fully enable bumping of intercepted SSL connections.
1774 Requires tproxy or intercept.
1776 Omitting the mode flag causes default forward proxy mode to be used.
1779 See http_port for a list of generic options
1784 cert= Path to SSL certificate (PEM format).
1786 key= Path to SSL private key file (PEM format)
1787 if not specified, the certificate file is
1788 assumed to be a combined certificate and
1791 version= The version of SSL/TLS supported
1792 1 automatic (default)
1797 cipher= Colon separated list of supported ciphers.
1799 options= Various SSL engine options. The most important
1801 NO_SSLv2 Disallow the use of SSLv2
1802 NO_SSLv3 Disallow the use of SSLv3
1803 NO_TLSv1 Disallow the use of TLSv1
1804 SINGLE_DH_USE Always create a new key when using
1805 temporary/ephemeral DH key exchanges
1806 See src/ssl_support.c or OpenSSL SSL_CTX_set_options
1807 documentation for a complete list of options.
1809 clientca= File containing the list of CAs to use when
1810 requesting a client certificate.
1812 cafile= File containing additional CA certificates to
1813 use when verifying client certificates. If unset
1814 clientca will be used.
1816 capath= Directory containing additional CA certificates
1817 and CRL lists to use when verifying client certificates.
1819 crlfile= File of additional CRL lists to use when verifying
1820 the client certificate, in addition to CRLs stored in
1821 the capath. Implies VERIFY_CRL flag below.
1823 dhparams= File containing DH parameters for temporary/ephemeral
1826 sslflags= Various flags modifying the use of SSL:
1828 Don't request client certificates
1829 immediately, but wait until acl processing
1830 requires a certificate (not yet implemented).
1832 Don't use the default CA lists built in
1835 Don't allow for session reuse. Each connection
1836 will result in a new SSL session.
1838 Verify CRL lists when accepting client
1841 Verify CRL lists for all certificates in the
1842 client certificate chain.
1844 sslcontext= SSL session ID context identifier.
1846 generate-host-certificates[=<on|off>]
1847 Dynamically create SSL server certificates for the
1848 destination hosts of bumped SSL requests.When
1849 enabled, the cert and key options are used to sign
1850 generated certificates. Otherwise generated
1851 certificate will be selfsigned.
1852 If there is CA certificate life time of generated
1853 certificate equals lifetime of CA certificate. If
1854 generated certificate is selfsigned lifetime is three
1856 This option is enabled by default when SslBump is used.
1857 See the sslBump option above for more information.
1859 dynamic_cert_mem_cache_size=SIZE
1860 Approximate total RAM size spent on cached generated
1861 certificates. If set to zero, caching is disabled. The
1862 default value is 4MB.
1864 See http_port for a list of available options.
1867 NAME: tcp_outgoing_tos tcp_outgoing_ds tcp_outgoing_dscp
1870 LOC: Ip::Qos::TheConfig.tosToServer
1872 Allows you to select a TOS/Diffserv value for packets outgoing
1873 on the server side, based on an ACL.
1875 tcp_outgoing_tos ds-field [!]aclname ...
1877 Example where normal_service_net uses the TOS value 0x00
1878 and good_service_net uses 0x20
1880 acl normal_service_net src 10.0.0.0/24
1881 acl good_service_net src 10.0.1.0/24
1882 tcp_outgoing_tos 0x00 normal_service_net
1883 tcp_outgoing_tos 0x20 good_service_net
1885 TOS/DSCP values really only have local significance - so you should
1886 know what you're specifying. For more information, see RFC2474,
1887 RFC2475, and RFC3260.
1889 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
1890 "default" to use whatever default your host has. Note that in
1891 practice often only multiples of 4 is usable as the two rightmost bits
1892 have been redefined for use by ECN (RFC 3168 section 23.1).
1894 Processing proceeds in the order specified, and stops at first fully
1897 Only fast ACLs are supported.
1900 NAME: clientside_tos
1903 LOC: Ip::Qos::TheConfig.tosToClient
1905 Allows you to select a TOS/Diffserv value for packets being transmitted
1906 on the client-side, based on an ACL.
1908 clientside_tos ds-field [!]aclname ...
1910 Example where normal_service_net uses the TOS value 0x00
1911 and good_service_net uses 0x20
1913 acl normal_service_net src 10.0.0.0/24
1914 acl good_service_net src 10.0.1.0/24
1915 clientside_tos 0x00 normal_service_net
1916 clientside_tos 0x20 good_service_net
1918 Note: This feature is incompatible with qos_flows. Any TOS values set here
1919 will be overwritten by TOS values in qos_flows.
1922 NAME: tcp_outgoing_mark
1924 IFDEF: SO_MARK&&USE_LIBCAP
1926 LOC: Ip::Qos::TheConfig.nfmarkToServer
1928 Allows you to apply a Netfilter mark value to outgoing packets
1929 on the server side, based on an ACL.
1931 tcp_outgoing_mark mark-value [!]aclname ...
1933 Example where normal_service_net uses the mark value 0x00
1934 and good_service_net uses 0x20
1936 acl normal_service_net src 10.0.0.0/24
1937 acl good_service_net src 10.0.1.0/24
1938 tcp_outgoing_mark 0x00 normal_service_net
1939 tcp_outgoing_mark 0x20 good_service_net
1941 Only fast ACLs are supported.
1944 NAME: clientside_mark
1946 IFDEF: SO_MARK&&USE_LIBCAP
1948 LOC: Ip::Qos::TheConfig.nfmarkToClient
1950 Allows you to apply a Netfilter mark value to packets being transmitted
1951 on the client-side, based on an ACL.
1953 clientside_mark mark-value [!]aclname ...
1955 Example where normal_service_net uses the mark value 0x00
1956 and good_service_net uses 0x20
1958 acl normal_service_net src 10.0.0.0/24
1959 acl good_service_net src 10.0.1.0/24
1960 clientside_mark 0x00 normal_service_net
1961 clientside_mark 0x20 good_service_net
1963 Note: This feature is incompatible with qos_flows. Any mark values set here
1964 will be overwritten by mark values in qos_flows.
1971 LOC: Ip::Qos::TheConfig
1973 Allows you to select a TOS/DSCP value to mark outgoing
1974 connections to the client, based on where the reply was sourced.
1975 For platforms using netfilter, allows you to set a netfilter mark
1976 value instead of, or in addition to, a TOS value.
1978 By default this functionality is disabled. To enable it with the default
1979 settings simply use "qos_flows mark" or "qos_flows tos". Default
1980 settings will result in the netfilter mark or TOS value being copied
1981 from the upstream connection to the client. Note that it is the connection
1982 CONNMARK value not the packet MARK value that is copied.
1984 It is not currently possible to copy the mark or TOS value from the
1985 client to the upstream connection request.
1987 TOS values really only have local significance - so you should
1988 know what you're specifying. For more information, see RFC2474,
1989 RFC2475, and RFC3260.
1991 The TOS/DSCP byte must be exactly that - a octet value 0 - 255. Note that
1992 in practice often only multiples of 4 is usable as the two rightmost bits
1993 have been redefined for use by ECN (RFC 3168 section 23.1).
1995 Mark values can be any unsigned 32-bit integer value.
1997 This setting is configured by setting the following values:
1999 tos|mark Whether to set TOS or netfilter mark values
2001 local-hit=0xFF Value to mark local cache hits.
2003 sibling-hit=0xFF Value to mark hits from sibling peers.
2005 parent-hit=0xFF Value to mark hits from parent peers.
2007 miss=0xFF[/mask] Value to mark cache misses. Takes precedence
2008 over the preserve-miss feature (see below), unless
2009 mask is specified, in which case only the bits
2010 specified in the mask are written.
2012 The TOS variant of the following features are only possible on Linux
2013 and require your kernel to be patched with the TOS preserving ZPH
2014 patch, available from http://zph.bratcheda.org
2015 No patch is needed to preserve the netfilter mark, which will work
2016 with all variants of netfilter.
2018 disable-preserve-miss
2019 This option disables the preservation of the TOS or netfilter
2020 mark. By default, the existing TOS or netfilter mark value of
2021 the response coming from the remote server will be retained
2022 and masked with miss-mark.
2023 NOTE: in the case of a netfilter mark, the mark must be set on
2024 the connection (using the CONNMARK target) not on the packet
2028 Allows you to mask certain bits in the TOS or mark value
2029 received from the remote server, before copying the value to
2030 the TOS sent towards clients.
2031 Default for tos: 0xFF (TOS from server is not changed).
2032 Default for mark: 0xFFFFFFFF (mark from server is not changed).
2034 All of these features require the --enable-zph-qos compilation flag
2035 (enabled by default). Netfilter marking also requires the
2036 libnetfilter_conntrack libraries (--with-netfilter-conntrack) and
2037 libcap 2.09+ (--with-libcap).
2041 NAME: tcp_outgoing_address
2044 DEFAULT_DOC: Address selection is performed by the operating system.
2045 LOC: Config.accessList.outgoing_address
2047 Allows you to map requests to different outgoing IP addresses
2048 based on the username or source address of the user making
2051 tcp_outgoing_address ipaddr [[!]aclname] ...
2054 Forwarding clients with dedicated IPs for certain subnets.
2056 acl normal_service_net src 10.0.0.0/24
2057 acl good_service_net src 10.0.2.0/24
2059 tcp_outgoing_address 2001:db8::c001 good_service_net
2060 tcp_outgoing_address 10.1.0.2 good_service_net
2062 tcp_outgoing_address 2001:db8::beef normal_service_net
2063 tcp_outgoing_address 10.1.0.1 normal_service_net
2065 tcp_outgoing_address 2001:db8::1
2066 tcp_outgoing_address 10.1.0.3
2068 Processing proceeds in the order specified, and stops at first fully
2071 Squid will add an implicit IP version test to each line.
2072 Requests going to IPv4 websites will use the outgoing 10.1.0.* addresses.
2073 Requests going to IPv6 websites will use the outgoing 2001:db8:* addresses.
2076 NOTE: The use of this directive using client dependent ACLs is
2077 incompatible with the use of server side persistent connections. To
2078 ensure correct results it is best to set server_persistent_connections
2079 to off when using this directive in such configurations.
2081 NOTE: The use of this directive to set a local IP on outgoing TCP links
2082 is incompatible with using TPROXY to set client IP out outbound TCP links.
2083 When needing to contact peers use the no-tproxy cache_peer option and the
2084 client_dst_passthru directive re-enable normal forwarding such as this.
2088 NAME: host_verify_strict
2091 LOC: Config.onoff.hostStrictVerify
2093 Regardless of this option setting, when dealing with intercepted
2094 traffic, Squid always verifies that the destination IP address matches
2095 the Host header domain or IP (called 'authority form URL').
2097 This enforcement is performed to satisfy a MUST-level requirement in
2098 RFC 2616 section 14.23: "The Host field value MUST represent the naming
2099 authority of the origin server or gateway given by the original URL".
2102 Squid always responds with an HTTP 409 (Conflict) error
2103 page and logs a security warning if there is no match.
2105 Squid verifies that the destination IP address matches
2106 the Host header for forward-proxy and reverse-proxy traffic
2107 as well. For those traffic types, Squid also enables the
2108 following checks, comparing the corresponding Host header
2109 and Request-URI components:
2111 * The host names (domain or IP) must be identical,
2112 but valueless or missing Host header disables all checks.
2113 For the two host names to match, both must be either IP
2116 * Port numbers must be identical, but if a port is missing
2117 the scheme-default port is assumed.
2120 When set to OFF (the default):
2121 Squid allows suspicious requests to continue but logs a
2122 security warning and blocks caching of the response.
2124 * Forward-proxy traffic is not checked at all.
2126 * Reverse-proxy traffic is not checked at all.
2128 * Intercepted traffic which passes verification is handled
2129 according to client_dst_passthru.
2131 * Intercepted requests which fail verification are sent
2132 to the client original destination instead of DIRECT.
2133 This overrides 'client_dst_passthru off'.
2135 For now suspicious intercepted CONNECT requests are always
2136 responded to with an HTTP 409 (Conflict) error page.
2141 As described in CVE-2009-0801 when the Host: header alone is used
2142 to determine the destination of a request it becomes trivial for
2143 malicious scripts on remote websites to bypass browser same-origin
2144 security policy and sandboxing protections.
2146 The cause of this is that such applets are allowed to perform their
2147 own HTTP stack, in which case the same-origin policy of the browser
2148 sandbox only verifies that the applet tries to contact the same IP
2149 as from where it was loaded at the IP level. The Host: header may
2150 be different from the connected IP and approved origin.
2154 NAME: client_dst_passthru
2157 LOC: Config.onoff.client_dst_passthru
2159 With NAT or TPROXY intercepted traffic Squid may pass the request
2160 directly to the original client destination IP or seek a faster
2161 source using the HTTP Host header.
2163 Using Host to locate alternative servers can provide faster
2164 connectivity with a range of failure recovery options.
2165 But can also lead to connectivity trouble when the client and
2166 server are attempting stateful interactions unaware of the proxy.
2168 This option (on by default) prevents alternative DNS entries being
2169 located to send intercepted traffic DIRECT to an origin server.
2170 The clients original destination IP and port will be used instead.
2172 Regardless of this option setting, when dealing with intercepted
2173 traffic Squid will verify the Host: header and any traffic which
2174 fails Host verification will be treated as if this option were ON.
2176 see host_verify_strict for details on the verification process.
2181 -----------------------------------------------------------------------------
2184 NAME: ssl_unclean_shutdown
2188 LOC: Config.SSL.unclean_shutdown
2190 Some browsers (especially MSIE) bugs out on SSL shutdown
2197 LOC: Config.SSL.ssl_engine
2200 The OpenSSL engine to use. You will need to set this if you
2201 would like to use hardware SSL acceleration for example.
2204 NAME: sslproxy_client_certificate
2207 LOC: Config.ssl_client.cert
2210 Client SSL Certificate to use when proxying https:// URLs
2213 NAME: sslproxy_client_key
2216 LOC: Config.ssl_client.key
2219 Client SSL Key to use when proxying https:// URLs
2222 NAME: sslproxy_version
2225 DEFAULT_DOC: automatic SSL/TLS version negotiation
2226 LOC: Config.ssl_client.version
2229 SSL version level to use when proxying https:// URLs
2231 The versions of SSL/TLS supported:
2233 1 automatic (default)
2241 NAME: sslproxy_options
2244 LOC: Config.ssl_client.options
2247 SSL implementation options to use when proxying https:// URLs
2249 The most important being:
2251 NO_SSLv2 Disallow the use of SSLv2
2252 NO_SSLv3 Disallow the use of SSLv3
2253 NO_TLSv1 Disallow the use of TLSv1.0
2254 NO_TLSv1_1 Disallow the use of TLSv1.1
2255 NO_TLSv1_2 Disallow the use of TLSv1.2
2257 Always create a new key when using temporary/ephemeral
2260 Disable use of RFC5077 session tickets. Some servers
2261 may have problems understanding the TLS extension due
2262 to ambiguous specification in RFC4507.
2263 ALL Enable various bug workarounds suggested as "harmless"
2264 by OpenSSL. Be warned that this may reduce SSL/TLS
2265 strength to some attacks.
2267 See the OpenSSL SSL_CTX_set_options documentation for a
2268 complete list of possible options.
2271 NAME: sslproxy_cipher
2274 LOC: Config.ssl_client.cipher
2277 SSL cipher list to use when proxying https:// URLs
2279 Colon separated list of supported ciphers.
2282 NAME: sslproxy_cafile
2285 LOC: Config.ssl_client.cafile
2288 file containing CA certificates to use when verifying server
2289 certificates while proxying https:// URLs
2292 NAME: sslproxy_capath
2295 LOC: Config.ssl_client.capath
2298 directory containing CA certificates to use when verifying
2299 server certificates while proxying https:// URLs
2302 NAME: sslproxy_session_ttl
2305 LOC: Config.SSL.session_ttl
2308 Sets the timeout value for SSL sessions
2311 NAME: sslproxy_session_cache_size
2314 LOC: Config.SSL.sessionCacheSize
2317 Sets the cache size to use for ssl session
2322 TYPE: sslproxy_ssl_bump
2323 LOC: Config.accessList.ssl_bump
2324 DEFAULT_DOC: Does not bump unless rules are present in squid.conf
2327 This option is consulted when a CONNECT request is received on
2328 an http_port (or a new connection is intercepted at an
2329 https_port), provided that port was configured with an ssl-bump
2330 flag. The subsequent data on the connection is either treated as
2331 HTTPS and decrypted OR tunneled at TCP level without decryption,
2332 depending on the first bumping "mode" which ACLs match.
2334 ssl_bump <mode> [!]acl ...
2336 The following bumping modes are supported:
2339 Allow bumping of the connection. Establish a secure connection
2340 with the client first, then connect to the server. This old mode
2341 does not allow Squid to mimic server SSL certificate and does
2342 not work with intercepted SSL connections.
2345 Allow bumping of the connection. Establish a secure connection
2346 with the server first, then establish a secure connection with
2347 the client, using a mimicked server certificate. Works with both
2348 CONNECT requests and intercepted SSL connections.
2351 Become a TCP tunnel without decoding the connection.
2352 Works with both CONNECT requests and intercepted SSL
2353 connections. This is the default behavior when no
2354 ssl_bump option is given or no ssl_bump ACLs match.
2356 By default, no connections are bumped.
2358 The first matching ssl_bump option wins. If no ACLs match, the
2359 connection is not bumped. Unlike most allow/deny ACL lists, ssl_bump
2360 does not have an implicit "negate the last given option" rule. You
2361 must make that rule explicit if you convert old ssl_bump allow/deny
2362 rules that rely on such an implicit rule.
2364 This clause supports both fast and slow acl types.
2365 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2367 See also: http_port ssl-bump, https_port ssl-bump
2370 # Example: Bump all requests except those originating from
2371 # localhost or those going to example.com.
2373 acl broken_sites dstdomain .example.com
2374 ssl_bump none localhost
2375 ssl_bump none broken_sites
2376 ssl_bump server-first all
2379 NAME: sslproxy_flags
2382 LOC: Config.ssl_client.flags
2385 Various flags modifying the use of SSL while proxying https:// URLs:
2386 DONT_VERIFY_PEER Accept certificates that fail verification.
2387 For refined control, see sslproxy_cert_error.
2388 NO_DEFAULT_CA Don't use the default CA list built in
2392 NAME: sslproxy_cert_error
2395 DEFAULT_DOC: Server certificate errors terminate the transaction.
2396 LOC: Config.ssl_client.cert_error
2399 Use this ACL to bypass server certificate validation errors.
2401 For example, the following lines will bypass all validation errors
2402 when talking to servers for example.com. All other
2403 validation errors will result in ERR_SECURE_CONNECT_FAIL error.
2405 acl BrokenButTrustedServers dstdomain example.com
2406 sslproxy_cert_error allow BrokenButTrustedServers
2407 sslproxy_cert_error deny all
2409 This clause only supports fast acl types.
2410 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2411 Using slow acl types may result in server crashes
2413 Without this option, all server certificate validation errors
2414 terminate the transaction to protect Squid and the client.
2416 SQUID_X509_V_ERR_INFINITE_VALIDATION error cannot be bypassed
2417 but should not happen unless your OpenSSL library is buggy.
2420 Bypassing validation errors is dangerous because an
2421 error usually implies that the server cannot be trusted
2422 and the connection may be insecure.
2424 See also: sslproxy_flags and DONT_VERIFY_PEER.
2427 NAME: sslproxy_cert_sign
2430 POSTSCRIPTUM: signUntrusted ssl::certUntrusted
2431 POSTSCRIPTUM: signSelf ssl::certSelfSigned
2432 POSTSCRIPTUM: signTrusted all
2433 TYPE: sslproxy_cert_sign
2434 LOC: Config.ssl_client.cert_sign
2437 sslproxy_cert_sign <signing algorithm> acl ...
2439 The following certificate signing algorithms are supported:
2442 Sign using the configured CA certificate which is usually
2443 placed in and trusted by end-user browsers. This is the
2444 default for trusted origin server certificates.
2447 Sign to guarantee an X509_V_ERR_CERT_UNTRUSTED browser error.
2448 This is the default for untrusted origin server certificates
2449 that are not self-signed (see ssl::certUntrusted).
2452 Sign using a self-signed certificate with the right CN to
2453 generate a X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT error in the
2454 browser. This is the default for self-signed origin server
2455 certificates (see ssl::certSelfSigned).
2457 This clause only supports fast acl types.
2459 When sslproxy_cert_sign acl(s) match, Squid uses the corresponding
2460 signing algorithm to generate the certificate and ignores all
2461 subsequent sslproxy_cert_sign options (the first match wins). If no
2462 acl(s) match, the default signing algorithm is determined by errors
2463 detected when obtaining and validating the origin server certificate.
2465 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2466 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2467 CONNECT request that carries a domain name. In all other cases (CONNECT
2468 to an IP address or an intercepted SSL connection), Squid cannot detect
2469 the domain mismatch at certificate generation time when
2470 bump-server-first is used.
2473 NAME: sslproxy_cert_adapt
2476 TYPE: sslproxy_cert_adapt
2477 LOC: Config.ssl_client.cert_adapt
2480 sslproxy_cert_adapt <adaptation algorithm> acl ...
2482 The following certificate adaptation algorithms are supported:
2485 Sets the "Not After" property to the "Not After" property of
2486 the CA certificate used to sign generated certificates.
2489 Sets the "Not Before" property to the "Not Before" property of
2490 the CA certificate used to sign generated certificates.
2492 setCommonName or setCommonName{CN}
2493 Sets Subject.CN property to the host name specified as a
2494 CN parameter or, if no explicit CN parameter was specified,
2495 extracted from the CONNECT request. It is a misconfiguration
2496 to use setCommonName without an explicit parameter for
2497 intercepted or tproxied SSL connections.
2499 This clause only supports fast acl types.
2501 Squid first groups sslproxy_cert_adapt options by adaptation algorithm.
2502 Within a group, when sslproxy_cert_adapt acl(s) match, Squid uses the
2503 corresponding adaptation algorithm to generate the certificate and
2504 ignores all subsequent sslproxy_cert_adapt options in that algorithm's
2505 group (i.e., the first match wins within each algorithm group). If no
2506 acl(s) match, the default mimicking action takes place.
2508 WARNING: SQUID_X509_V_ERR_DOMAIN_MISMATCH and ssl:certDomainMismatch can
2509 be used with sslproxy_cert_adapt, but if and only if Squid is bumping a
2510 CONNECT request that carries a domain name. In all other cases (CONNECT
2511 to an IP address or an intercepted SSL connection), Squid cannot detect
2512 the domain mismatch at certificate generation time when
2513 bump-server-first is used.
2516 NAME: sslpassword_program
2519 LOC: Config.Program.ssl_password
2522 Specify a program used for entering SSL key passphrases
2523 when using encrypted SSL certificate keys. If not specified
2524 keys must either be unencrypted, or Squid started with the -N
2525 option to allow it to query interactively for the passphrase.
2527 The key file name is given as argument to the program allowing
2528 selection of the right password if you have multiple encrypted
2533 OPTIONS RELATING TO EXTERNAL SSL_CRTD
2534 -----------------------------------------------------------------------------
2537 NAME: sslcrtd_program
2540 DEFAULT: @DEFAULT_SSL_CRTD@ -s @DEFAULT_SSL_DB_DIR@ -M 4MB
2541 LOC: Ssl::TheConfig.ssl_crtd
2543 Specify the location and options of the executable for ssl_crtd process.
2544 @DEFAULT_SSL_CRTD@ program requires -s and -M parameters
2545 For more information use:
2546 @DEFAULT_SSL_CRTD@ -h
2549 NAME: sslcrtd_children
2550 TYPE: HelperChildConfig
2552 DEFAULT: 32 startup=5 idle=1
2553 LOC: Ssl::TheConfig.ssl_crtdChildren
2555 The maximum number of processes spawn to service ssl server.
2556 The maximum this may be safely set to is 32.
2558 The startup= and idle= options allow some measure of skew in your
2563 Sets the minimum number of processes to spawn when Squid
2564 starts or reconfigures. When set to zero the first request will
2565 cause spawning of the first child process to handle it.
2567 Starting too few children temporary slows Squid under load while it
2568 tries to spawn enough additional processes to cope with traffic.
2572 Sets a minimum of how many processes Squid is to try and keep available
2573 at all times. When traffic begins to rise above what the existing
2574 processes can handle this many more will be spawned up to the maximum
2575 configured. A minimum setting of 1 is required.
2577 You must have at least one ssl_crtd process.
2580 NAME: sslcrtvalidator_program
2584 LOC: Ssl::TheConfig.ssl_crt_validator
2586 Specify the location and options of the executable for ssl_crt_validator
2589 Usage: sslcrtvalidator_program [ttl=n] [cache=n] path ...
2592 ttl=n TTL in seconds for cached results. The default is 60 secs
2593 cache=n limit the result cache size. The default value is 2048
2596 NAME: sslcrtvalidator_children
2597 TYPE: HelperChildConfig
2599 DEFAULT: 32 startup=5 idle=1 concurrency=1
2600 LOC: Ssl::TheConfig.ssl_crt_validator_Children
2602 The maximum number of processes spawn to service SSL server.
2603 The maximum this may be safely set to is 32.
2605 The startup= and idle= options allow some measure of skew in your
2610 Sets the minimum number of processes to spawn when Squid
2611 starts or reconfigures. When set to zero the first request will
2612 cause spawning of the first child process to handle it.
2614 Starting too few children temporary slows Squid under load while it
2615 tries to spawn enough additional processes to cope with traffic.
2619 Sets a minimum of how many processes Squid is to try and keep available
2620 at all times. When traffic begins to rise above what the existing
2621 processes can handle this many more will be spawned up to the maximum
2622 configured. A minimum setting of 1 is required.
2626 The number of requests each certificate validator helper can handle in
2627 parallel. A value of 0 indicates the certficate validator does not
2628 support concurrency. Defaults to 1.
2630 When this directive is set to a value >= 1 then the protocol
2631 used to communicate with the helper is modified to include
2632 a request ID in front of the request/response. The request
2633 ID from the request must be echoed back with the response
2636 You must have at least one ssl_crt_validator process.
2640 OPTIONS WHICH AFFECT THE NEIGHBOR SELECTION ALGORITHM
2641 -----------------------------------------------------------------------------
2649 To specify other caches in a hierarchy, use the format:
2651 cache_peer hostname type http-port icp-port [options]
2656 # hostname type port port options
2657 # -------------------- -------- ----- ----- -----------
2658 cache_peer parent.foo.net parent 3128 3130 default
2659 cache_peer sib1.foo.net sibling 3128 3130 proxy-only
2660 cache_peer sib2.foo.net sibling 3128 3130 proxy-only
2661 cache_peer example.com parent 80 0 default
2662 cache_peer cdn.example.com sibling 3128 0
2664 type: either 'parent', 'sibling', or 'multicast'.
2666 proxy-port: The port number where the peer accept HTTP requests.
2667 For other Squid proxies this is usually 3128
2668 For web servers this is usually 80
2670 icp-port: Used for querying neighbor caches about objects.
2671 Set to 0 if the peer does not support ICP or HTCP.
2672 See ICP and HTCP options below for additional details.
2675 ==== ICP OPTIONS ====
2677 You MUST also set icp_port and icp_access explicitly when using these options.
2678 The defaults will prevent peer traffic using ICP.
2681 no-query Disable ICP queries to this neighbor.
2684 Indicates the named peer is a member of a multicast group.
2685 ICP queries will not be sent directly to the peer, but ICP
2686 replies will be accepted from it.
2688 closest-only Indicates that, for ICP_OP_MISS replies, we'll only forward
2689 CLOSEST_PARENT_MISSes and never FIRST_PARENT_MISSes.
2692 To only send ICP queries to this neighbor infrequently.
2693 This is used to keep the neighbor round trip time updated
2694 and is usually used in conjunction with weighted-round-robin.
2697 ==== HTCP OPTIONS ====
2699 You MUST also set htcp_port and htcp_access explicitly when using these options.
2700 The defaults will prevent peer traffic using HTCP.
2703 htcp Send HTCP, instead of ICP, queries to the neighbor.
2704 You probably also want to set the "icp-port" to 4827
2705 instead of 3130. This directive accepts a comma separated
2706 list of options described below.
2708 htcp=oldsquid Send HTCP to old Squid versions (2.5 or earlier).
2710 htcp=no-clr Send HTCP to the neighbor but without
2711 sending any CLR requests. This cannot be used with
2714 htcp=only-clr Send HTCP to the neighbor but ONLY CLR requests.
2715 This cannot be used with no-clr.
2718 Send HTCP to the neighbor including CLRs but only when
2719 they do not result from PURGE requests.
2722 Forward any HTCP CLR requests this proxy receives to the peer.
2725 ==== PEER SELECTION METHODS ====
2727 The default peer selection method is ICP, with the first responding peer
2728 being used as source. These options can be used for better load balancing.
2731 default This is a parent cache which can be used as a "last-resort"
2732 if a peer cannot be located by any of the peer-selection methods.
2733 If specified more than once, only the first is used.
2735 round-robin Load-Balance parents which should be used in a round-robin
2736 fashion in the absence of any ICP queries.
2737 weight=N can be used to add bias.
2739 weighted-round-robin
2740 Load-Balance parents which should be used in a round-robin
2741 fashion with the frequency of each parent being based on the
2742 round trip time. Closer parents are used more often.
2743 Usually used for background-ping parents.
2744 weight=N can be used to add bias.
2746 carp Load-Balance parents which should be used as a CARP array.
2747 The requests will be distributed among the parents based on the
2748 CARP load balancing hash function based on their weight.
2750 userhash Load-balance parents based on the client proxy_auth or ident username.
2752 sourcehash Load-balance parents based on the client source IP.
2755 To be used only for cache peers of type "multicast".
2756 ALL members of this multicast group have "sibling"
2757 relationship with it, not "parent". This is to a multicast
2758 group when the requested object would be fetched only from
2759 a "parent" cache, anyway. It's useful, e.g., when
2760 configuring a pool of redundant Squid proxies, being
2761 members of the same multicast group.
2764 ==== PEER SELECTION OPTIONS ====
2766 weight=N use to affect the selection of a peer during any weighted
2767 peer-selection mechanisms.
2768 The weight must be an integer; default is 1,
2769 larger weights are favored more.
2770 This option does not affect parent selection if a peering
2771 protocol is not in use.
2773 basetime=N Specify a base amount to be subtracted from round trip
2775 It is subtracted before division by weight in calculating
2776 which parent to fectch from. If the rtt is less than the
2777 base time the rtt is set to a minimal value.
2779 ttl=N Specify a TTL to use when sending multicast ICP queries
2781 Only useful when sending to a multicast group.
2782 Because we don't accept ICP replies from random
2783 hosts, you must configure other group members as
2784 peers with the 'multicast-responder' option.
2786 no-delay To prevent access to this neighbor from influencing the
2789 digest-url=URL Tell Squid to fetch the cache digest (if digests are
2790 enabled) for this host from the specified URL rather
2791 than the Squid default location.
2794 ==== CARP OPTIONS ====
2796 carp-key=key-specification
2797 use a different key than the full URL to hash against the peer.
2798 the key-specification is a comma-separated list of the keywords
2799 scheme, host, port, path, params
2800 Order is not important.
2802 ==== ACCELERATOR / REVERSE-PROXY OPTIONS ====
2804 originserver Causes this parent to be contacted as an origin server.
2805 Meant to be used in accelerator setups when the peer
2809 Set the Host header of requests forwarded to this peer.
2810 Useful in accelerator setups where the server (peer)
2811 expects a certain domain name but clients may request
2812 others. ie example.com or www.example.com
2814 no-digest Disable request of cache digests.
2817 Disables requesting ICMP RTT database (NetDB).
2820 ==== AUTHENTICATION OPTIONS ====
2823 If this is a personal/workgroup proxy and your parent
2824 requires proxy authentication.
2826 Note: The string can include URL escapes (i.e. %20 for
2827 spaces). This also means % must be written as %%.
2830 Send login details received from client to this peer.
2831 Both Proxy- and WWW-Authorization headers are passed
2832 without alteration to the peer.
2833 Authentication is not required by Squid for this to work.
2835 Note: This will pass any form of authentication but
2836 only Basic auth will work through a proxy unless the
2837 connection-auth options are also used.
2839 login=PASS Send login details received from client to this peer.
2840 Authentication is not required by this option.
2842 If there are no client-provided authentication headers
2843 to pass on, but username and password are available
2844 from an external ACL user= and password= result tags
2845 they may be sent instead.
2847 Note: To combine this with proxy_auth both proxies must
2848 share the same user database as HTTP only allows for
2849 a single login (one for proxy, one for origin server).
2850 Also be warned this will expose your users proxy
2851 password to the peer. USE WITH CAUTION
2854 Send the username to the upstream cache, but with a
2855 fixed password. This is meant to be used when the peer
2856 is in another administrative domain, but it is still
2857 needed to identify each user.
2858 The star can optionally be followed by some extra
2859 information which is added to the username. This can
2860 be used to identify this proxy to the peer, similar to
2861 the login=username:password option above.
2864 If this is a personal/workgroup proxy and your parent
2865 requires a secure proxy authentication.
2866 The first principal from the default keytab or defined by
2867 the environment variable KRB5_KTNAME will be used.
2869 WARNING: The connection may transmit requests from multiple
2870 clients. Negotiate often assumes end-to-end authentication
2871 and a single-client. Which is not strictly true here.
2873 login=NEGOTIATE:principal_name
2874 If this is a personal/workgroup proxy and your parent
2875 requires a secure proxy authentication.
2876 The principal principal_name from the default keytab or
2877 defined by the environment variable KRB5_KTNAME will be
2880 WARNING: The connection may transmit requests from multiple
2881 clients. Negotiate often assumes end-to-end authentication
2882 and a single-client. Which is not strictly true here.
2884 connection-auth=on|off
2885 Tell Squid that this peer does or not support Microsoft
2886 connection oriented authentication, and any such
2887 challenges received from there should be ignored.
2888 Default is auto to automatically determine the status
2892 ==== SSL / HTTPS / TLS OPTIONS ====
2894 ssl Encrypt connections to this peer with SSL/TLS.
2896 sslcert=/path/to/ssl/certificate
2897 A client SSL certificate to use when connecting to
2900 sslkey=/path/to/ssl/key
2901 The private SSL key corresponding to sslcert above.
2902 If 'sslkey' is not specified 'sslcert' is assumed to
2903 reference a combined file containing both the
2904 certificate and the key.
2906 sslversion=1|2|3|4|5|6
2907 The SSL version to use when connecting to this peer
2908 1 = automatic (default)
2915 sslcipher=... The list of valid SSL ciphers to use when connecting
2918 ssloptions=... Specify various SSL implementation options:
2920 NO_SSLv2 Disallow the use of SSLv2
2921 NO_SSLv3 Disallow the use of SSLv3
2922 NO_TLSv1 Disallow the use of TLSv1.0
2923 NO_TLSv1_1 Disallow the use of TLSv1.1
2924 NO_TLSv1_2 Disallow the use of TLSv1.2
2926 Always create a new key when using
2927 temporary/ephemeral DH key exchanges
2928 ALL Enable various bug workarounds
2929 suggested as "harmless" by OpenSSL
2930 Be warned that this reduces SSL/TLS
2931 strength to some attacks.
2933 See the OpenSSL SSL_CTX_set_options documentation for a
2936 sslcafile=... A file containing additional CA certificates to use
2937 when verifying the peer certificate.
2939 sslcapath=... A directory containing additional CA certificates to
2940 use when verifying the peer certificate.
2942 sslcrlfile=... A certificate revocation list file to use when
2943 verifying the peer certificate.
2945 sslflags=... Specify various flags modifying the SSL implementation:
2948 Accept certificates even if they fail to
2951 Don't use the default CA list built in
2954 Don't verify the peer certificate
2955 matches the server name
2957 ssldomain= The peer name as advertised in it's certificate.
2958 Used for verifying the correctness of the received peer
2959 certificate. If not specified the peer hostname will be
2963 Enable the "Front-End-Https: On" header needed when
2964 using Squid as a SSL frontend in front of Microsoft OWA.
2965 See MS KB document Q307347 for details on this header.
2966 If set to auto the header will only be added if the
2967 request is forwarded as a https:// URL.
2970 ==== GENERAL OPTIONS ====
2973 A peer-specific connect timeout.
2974 Also see the peer_connect_timeout directive.
2976 connect-fail-limit=N
2977 How many times connecting to a peer must fail before
2978 it is marked as down. Standby connection failures
2979 count towards this limit. Default is 10.
2981 allow-miss Disable Squid's use of only-if-cached when forwarding
2982 requests to siblings. This is primarily useful when
2983 icp_hit_stale is used by the sibling. To extensive use
2984 of this option may result in forwarding loops, and you
2985 should avoid having two-way peerings with this option.
2986 For example to deny peer usage on requests from peer
2987 by denying cache_peer_access if the source is a peer.
2989 max-conn=N Limit the number of concurrent connections the Squid
2990 may open to this peer, including already opened idle
2991 and standby connections. There is no peer-specific
2992 connection limit by default.
2994 A peer exceeding the limit is not used for new
2995 requests unless a standby connection is available.
2997 max-conn currently works poorly with idle persistent
2998 connections: When a peer reaches its max-conn limit,
2999 and there are idle persistent connections to the peer,
3000 the peer may not be selected because the limiting code
3001 does not know whether Squid can reuse those idle
3004 standby=N Maintain a pool of N "hot standby" connections to an
3005 UP peer, available for requests when no idle
3006 persistent connection is available (or safe) to use.
3007 By default and with zero N, no such pool is maintained.
3008 N must not exceed the max-conn limit (if any).
3010 At start or after reconfiguration, Squid opens new TCP
3011 standby connections until there are N connections
3012 available and then replenishes the standby pool as
3013 opened connections are used up for requests. A used
3014 connection never goes back to the standby pool, but
3015 may go to the regular idle persistent connection pool
3016 shared by all peers and origin servers.
3018 Squid never opens multiple new standby connections
3019 concurrently. This one-at-a-time approach minimizes
3020 flooding-like effect on peers. Furthermore, just a few
3021 standby connections should be sufficient in most cases
3022 to supply most new requests with a ready-to-use
3025 Standby connections obey server_idle_pconn_timeout.
3026 For the feature to work as intended, the peer must be
3027 configured to accept and keep them open longer than
3028 the idle timeout at the connecting Squid, to minimize
3029 race conditions typical to idle used persistent
3030 connections. Default request_timeout and
3031 server_idle_pconn_timeout values ensure such a
3034 name=xxx Unique name for the peer.
3035 Required if you have multiple peers on the same host
3036 but different ports.
3037 This name can be used in cache_peer_access and similar
3038 directives to dentify the peer.
3039 Can be used by outgoing access controls through the
3042 no-tproxy Do not use the client-spoof TPROXY support when forwarding
3043 requests to this peer. Use normal address selection instead.
3044 This overrides the spoof_client_ip ACL.
3046 proxy-only objects fetched from the peer will not be stored locally.
3050 NAME: cache_peer_domain cache_host_domain
3055 Use to limit the domains for which a neighbor cache will be
3059 cache_peer_domain cache-host domain [domain ...]
3060 cache_peer_domain cache-host !domain
3062 For example, specifying
3064 cache_peer_domain parent.foo.net .edu
3066 has the effect such that UDP query packets are sent to
3067 'bigserver' only when the requested object exists on a
3068 server in the .edu domain. Prefixing the domainname
3069 with '!' means the cache will be queried for objects
3072 NOTE: * Any number of domains may be given for a cache-host,
3073 either on the same or separate lines.
3074 * When multiple domains are given for a particular
3075 cache-host, the first matched domain is applied.
3076 * Cache hosts with no domain restrictions are queried
3078 * There are no defaults.
3079 * There is also a 'cache_peer_access' tag in the ACL
3083 NAME: cache_peer_access
3088 Similar to 'cache_peer_domain' but provides more flexibility by
3092 cache_peer_access cache-host allow|deny [!]aclname ...
3094 The syntax is identical to 'http_access' and the other lists of
3095 ACL elements. See the comments for 'http_access' below, or
3096 the Squid FAQ (http://wiki.squid-cache.org/SquidFaq/SquidAcl).
3099 NAME: neighbor_type_domain
3100 TYPE: hostdomaintype
3102 DEFAULT_DOC: The peer type from cache_peer directive is used for all requests to that peer.
3105 Modify the cache_peer neighbor type when passing requests
3106 about specific domains to the peer.
3109 neighbor_type_domain neighbor parent|sibling domain domain ...
3112 cache_peer foo.example.com parent 3128 3130
3113 neighbor_type_domain foo.example.com sibling .au .de
3115 The above configuration treats all requests to foo.example.com as a
3116 parent proxy unless the request is for a .au or .de ccTLD domain name.
3119 NAME: dead_peer_timeout
3123 LOC: Config.Timeout.deadPeer
3125 This controls how long Squid waits to declare a peer cache
3126 as "dead." If there are no ICP replies received in this
3127 amount of time, Squid will declare the peer dead and not
3128 expect to receive any further ICP replies. However, it
3129 continues to send ICP queries, and will mark the peer as
3130 alive upon receipt of the first subsequent ICP reply.
3132 This timeout also affects when Squid expects to receive ICP
3133 replies from peers. If more than 'dead_peer' seconds have
3134 passed since the last ICP reply was received, Squid will not
3135 expect to receive an ICP reply on the next query. Thus, if
3136 your time between requests is greater than this timeout, you
3137 will see a lot of requests sent DIRECT to origin servers
3138 instead of to your parents.
3141 NAME: forward_max_tries
3144 LOC: Config.forward_max_tries
3146 Controls how many different forward paths Squid will try
3147 before giving up. See also forward_timeout.
3149 NOTE: connect_retries (default: none) can make each of these
3150 possible forwarding paths be tried multiple times.
3153 NAME: hierarchy_stoplist
3156 LOC: Config.hierarchy_stoplist
3158 A list of words which, if found in a URL, cause the object to
3159 be handled directly by this cache. In other words, use this
3160 to not query neighbor caches for certain objects. You may
3161 list this option multiple times.
3164 hierarchy_stoplist cgi-bin ?
3166 Note: never_direct overrides this option.
3170 MEMORY CACHE OPTIONS
3171 -----------------------------------------------------------------------------
3178 LOC: Config.memMaxSize
3180 NOTE: THIS PARAMETER DOES NOT SPECIFY THE MAXIMUM PROCESS SIZE.
3181 IT ONLY PLACES A LIMIT ON HOW MUCH ADDITIONAL MEMORY SQUID WILL
3182 USE AS A MEMORY CACHE OF OBJECTS. SQUID USES MEMORY FOR OTHER
3183 THINGS AS WELL. SEE THE SQUID FAQ SECTION 8 FOR DETAILS.
3185 'cache_mem' specifies the ideal amount of memory to be used
3187 * In-Transit objects
3189 * Negative-Cached objects
3191 Data for these objects are stored in 4 KB blocks. This
3192 parameter specifies the ideal upper limit on the total size of
3193 4 KB blocks allocated. In-Transit objects take the highest
3196 In-transit objects have priority over the others. When
3197 additional space is needed for incoming data, negative-cached
3198 and hot objects will be released. In other words, the
3199 negative-cached and hot objects will fill up any unused space
3200 not needed for in-transit objects.
3202 If circumstances require, this limit will be exceeded.
3203 Specifically, if your incoming request rate requires more than
3204 'cache_mem' of memory to hold in-transit objects, Squid will
3205 exceed this limit to satisfy the new requests. When the load
3206 decreases, blocks will be freed until the high-water mark is
3207 reached. Thereafter, blocks will be used to store hot
3210 If shared memory caching is enabled, Squid does not use the shared
3211 cache space for in-transit objects, but they still consume as much
3212 local memory as they need. For more details about the shared memory
3213 cache, see memory_cache_shared.
3216 NAME: maximum_object_size_in_memory
3220 LOC: Config.Store.maxInMemObjSize
3222 Objects greater than this size will not be attempted to kept in
3223 the memory cache. This should be set high enough to keep objects
3224 accessed frequently in memory to improve performance whilst low
3225 enough to keep larger objects from hoarding cache_mem.
3228 NAME: memory_cache_shared
3231 LOC: Config.memShared
3233 DEFAULT_DOC: "on" where supported if doing memory caching with multiple SMP workers.
3235 Controls whether the memory cache is shared among SMP workers.
3237 The shared memory cache is meant to occupy cache_mem bytes and replace
3238 the non-shared memory cache, although some entities may still be
3239 cached locally by workers for now (e.g., internal and in-transit
3240 objects may be served from a local memory cache even if shared memory
3241 caching is enabled).
3243 By default, the memory cache is shared if and only if all of the
3244 following conditions are satisfied: Squid runs in SMP mode with
3245 multiple workers, cache_mem is positive, and Squid environment
3246 supports required IPC primitives (e.g., POSIX shared memory segments
3247 and GCC-style atomic operations).
3249 To avoid blocking locks, shared memory uses opportunistic algorithms
3250 that do not guarantee that every cachable entity that could have been
3251 shared among SMP workers will actually be shared.
3253 Currently, entities exceeding 32KB in size cannot be shared.
3256 NAME: memory_cache_mode
3260 DEFAULT_DOC: Keep the most recently fetched objects in memory
3262 Controls which objects to keep in the memory cache (cache_mem)
3264 always Keep most recently fetched objects in memory (default)
3266 disk Only disk cache hits are kept in memory, which means
3267 an object must first be cached on disk and then hit
3268 a second time before cached in memory.
3270 network Only objects fetched from network is kept in memory
3273 NAME: memory_replacement_policy
3275 LOC: Config.memPolicy
3278 The memory replacement policy parameter determines which
3279 objects are purged from memory when memory space is needed.
3281 See cache_replacement_policy for details on algorithms.
3286 -----------------------------------------------------------------------------
3289 NAME: cache_replacement_policy
3291 LOC: Config.replPolicy
3294 The cache replacement policy parameter determines which
3295 objects are evicted (replaced) when disk space is needed.
3297 lru : Squid's original list based LRU policy
3298 heap GDSF : Greedy-Dual Size Frequency
3299 heap LFUDA: Least Frequently Used with Dynamic Aging
3300 heap LRU : LRU policy implemented using a heap
3302 Applies to any cache_dir lines listed below this directive.
3304 The LRU policies keeps recently referenced objects.
3306 The heap GDSF policy optimizes object hit rate by keeping smaller
3307 popular objects in cache so it has a better chance of getting a
3308 hit. It achieves a lower byte hit rate than LFUDA though since
3309 it evicts larger (possibly popular) objects.
3311 The heap LFUDA policy keeps popular objects in cache regardless of
3312 their size and thus optimizes byte hit rate at the expense of
3313 hit rate since one large, popular object will prevent many
3314 smaller, slightly less popular objects from being cached.
3316 Both policies utilize a dynamic aging mechanism that prevents
3317 cache pollution that can otherwise occur with frequency-based
3318 replacement policies.
3320 NOTE: if using the LFUDA replacement policy you should increase
3321 the value of maximum_object_size above its default of 4 MB to
3322 to maximize the potential byte hit rate improvement of LFUDA.
3324 For more information about the GDSF and LFUDA cache replacement
3325 policies see http://www.hpl.hp.com/techreports/1999/HPL-1999-69.html
3326 and http://fog.hpl.external.hp.com/techreports/98/HPL-98-173.html.
3329 NAME: minimum_object_size
3333 DEFAULT_DOC: no limit
3334 LOC: Config.Store.minObjectSize
3336 Objects smaller than this size will NOT be saved on disk. The
3337 value is specified in bytes, and the default is 0 KB, which
3338 means all responses can be stored.
3341 NAME: maximum_object_size
3345 LOC: Config.Store.maxObjectSize
3347 Set the default value for max-size parameter on any cache_dir.
3348 The value is specified in bytes, and the default is 4 MB.
3350 If you wish to get a high BYTES hit ratio, you should probably
3351 increase this (one 32 MB object hit counts for 3200 10KB
3354 If you wish to increase hit ratio more than you want to
3355 save bandwidth you should leave this low.
3357 NOTE: if using the LFUDA replacement policy you should increase
3358 this value to maximize the byte hit rate improvement of LFUDA!
3359 See cache_replacement_policy for a discussion of this policy.
3365 DEFAULT_DOC: No disk cache. Store cache ojects only in memory.
3366 LOC: Config.cacheSwap
3369 cache_dir Type Directory-Name Fs-specific-data [options]
3371 You can specify multiple cache_dir lines to spread the
3372 cache among different disk partitions.
3374 Type specifies the kind of storage system to use. Only "ufs"
3375 is built by default. To enable any of the other storage systems
3376 see the --enable-storeio configure option.
3378 'Directory' is a top-level directory where cache swap
3379 files will be stored. If you want to use an entire disk
3380 for caching, this can be the mount-point directory.
3381 The directory must exist and be writable by the Squid
3382 process. Squid will NOT create this directory for you.
3384 In SMP configurations, cache_dir must not precede the workers option
3385 and should use configuration macros or conditionals to give each
3386 worker interested in disk caching a dedicated cache directory.
3389 ==== The ufs store type ====
3391 "ufs" is the old well-known Squid storage format that has always
3395 cache_dir ufs Directory-Name Mbytes L1 L2 [options]
3397 'Mbytes' is the amount of disk space (MB) to use under this
3398 directory. The default is 100 MB. Change this to suit your
3399 configuration. Do NOT put the size of your disk drive here.
3400 Instead, if you want Squid to use the entire disk drive,
3401 subtract 20% and use that value.
3403 'L1' is the number of first-level subdirectories which
3404 will be created under the 'Directory'. The default is 16.
3406 'L2' is the number of second-level subdirectories which
3407 will be created under each first-level directory. The default
3411 ==== The aufs store type ====
3413 "aufs" uses the same storage format as "ufs", utilizing
3414 POSIX-threads to avoid blocking the main Squid process on
3415 disk-I/O. This was formerly known in Squid as async-io.
3418 cache_dir aufs Directory-Name Mbytes L1 L2 [options]
3420 see argument descriptions under ufs above
3423 ==== The diskd store type ====
3425 "diskd" uses the same storage format as "ufs", utilizing a
3426 separate process to avoid blocking the main Squid process on
3430 cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n]
3432 see argument descriptions under ufs above
3434 Q1 specifies the number of unacknowledged I/O requests when Squid
3435 stops opening new files. If this many messages are in the queues,
3436 Squid won't open new files. Default is 64
3438 Q2 specifies the number of unacknowledged messages when Squid
3439 starts blocking. If this many messages are in the queues,
3440 Squid blocks until it receives some replies. Default is 72
3442 When Q1 < Q2 (the default), the cache directory is optimized
3443 for lower response time at the expense of a decrease in hit
3444 ratio. If Q1 > Q2, the cache directory is optimized for
3445 higher hit ratio at the expense of an increase in response
3449 ==== The rock store type ====
3452 cache_dir rock Directory-Name Mbytes [options]
3454 The Rock Store type is a database-style storage. All cached
3455 entries are stored in a "database" file, using fixed-size slots.
3456 A single entry occupies one or more slots.
3458 If possible, Squid using Rock Store creates a dedicated kid
3459 process called "disker" to avoid blocking Squid worker(s) on disk
3460 I/O. One disker kid is created for each rock cache_dir. Diskers
3461 are created only when Squid, running in daemon mode, has support
3462 for the IpcIo disk I/O module.
3464 swap-timeout=msec: Squid will not start writing a miss to or
3465 reading a hit from disk if it estimates that the swap operation
3466 will take more than the specified number of milliseconds. By
3467 default and when set to zero, disables the disk I/O time limit
3468 enforcement. Ignored when using blocking I/O module because
3469 blocking synchronous I/O does not allow Squid to estimate the
3470 expected swap wait time.
3472 max-swap-rate=swaps/sec: Artificially limits disk access using
3473 the specified I/O rate limit. Swap out requests that
3474 would cause the average I/O rate to exceed the limit are
3475 delayed. Individual swap in requests (i.e., hits or reads) are
3476 not delayed, but they do contribute to measured swap rate and
3477 since they are placed in the same FIFO queue as swap out
3478 requests, they may wait longer if max-swap-rate is smaller.
3479 This is necessary on file systems that buffer "too
3480 many" writes and then start blocking Squid and other processes
3481 while committing those writes to disk. Usually used together
3482 with swap-timeout to avoid excessive delays and queue overflows
3483 when disk demand exceeds available disk "bandwidth". By default
3484 and when set to zero, disables the disk I/O rate limit
3485 enforcement. Currently supported by IpcIo module only.
3487 slot-size=bytes: The size of a database "record" used for
3488 storing cached responses. A cached response occupies at least
3489 one slot and all database I/O is done using individual slots so
3490 increasing this parameter leads to more disk space waste while
3491 decreasing it leads to more disk I/O overheads. Should be a
3492 multiple of your operating system I/O page size. Defaults to
3493 16KBytes. A housekeeping header is stored with each slot and
3494 smaller slot-sizes will be rejected. The header is smaller than
3498 ==== COMMON OPTIONS ====
3500 no-store no new objects should be stored to this cache_dir.
3502 min-size=n the minimum object size in bytes this cache_dir
3503 will accept. It's used to restrict a cache_dir
3504 to only store large objects (e.g. AUFS) while
3505 other stores are optimized for smaller objects
3509 max-size=n the maximum object size in bytes this cache_dir
3511 The value in maximum_object_size directive sets
3512 the default unless more specific details are
3513 available (ie a small store capacity).
3515 Note: To make optimal use of the max-size limits you should order
3516 the cache_dir lines with the smallest max-size value first.
3520 # Uncomment and adjust the following to add a disk cache directory.
3521 #cache_dir ufs @DEFAULT_SWAP_DIR@ 100 16 256
3525 NAME: store_dir_select_algorithm
3527 LOC: Config.store_dir_select_algorithm
3530 How Squid selects which cache_dir to use when the response
3531 object will fit into more than one.
3533 Regardless of which algorithm is used the cache_dir min-size
3534 and max-size parameters are obeyed. As such they can affect
3535 the selection algorithm by limiting the set of considered
3542 This algorithm is suited to caches with similar cache_dir
3543 sizes and disk speeds.
3545 The disk with the least I/O pending is selected.
3546 When there are multiple disks with the same I/O load ranking
3547 the cache_dir with most available capacity is selected.
3549 When a mix of cache_dir sizes are configured the faster disks
3550 have a naturally lower I/O loading and larger disks have more
3551 capacity. So space used to store objects and data throughput
3552 may be very unbalanced towards larger disks.
3557 This algorithm is suited to caches with unequal cache_dir
3560 Each cache_dir is selected in a rotation. The next suitable
3563 Available cache_dir capacity is only considered in relation
3564 to whether the object will fit and meets the min-size and
3565 max-size parameters.
3567 Disk I/O loading is only considered to prevent overload on slow
3568 disks. This algorithm does not spread objects by size, so any
3569 I/O loading per-disk may appear very unbalanced and volatile.
3571 If several cache_dirs use similar min-size, max-size, or other
3572 limits to to reject certain responses, then do not group such
3573 cache_dir lines together, to avoid round-robin selection bias
3574 towards the first cache_dir after the group. Instead, interleave
3575 cache_dir lines from different groups. For example:
3577 store_dir_select_algorithm round-robin
3578 cache_dir rock /hdd1 ... min-size=100000
3579 cache_dir rock /ssd1 ... max-size=99999
3580 cache_dir rock /hdd2 ... min-size=100000
3581 cache_dir rock /ssd2 ... max-size=99999
3582 cache_dir rock /hdd3 ... min-size=100000
3583 cache_dir rock /ssd3 ... max-size=99999
3586 NAME: max_open_disk_fds
3588 LOC: Config.max_open_disk_fds
3590 DEFAULT_DOC: no limit
3592 To avoid having disk as the I/O bottleneck Squid can optionally
3593 bypass the on-disk cache if more than this amount of disk file
3594 descriptors are open.
3596 A value of 0 indicates no limit.
3599 NAME: cache_swap_low
3600 COMMENT: (percent, 0-100)
3603 LOC: Config.Swap.lowWaterMark
3605 The low-water mark for cache object replacement.
3606 Replacement begins when the swap (disk) usage is above the
3607 low-water mark and attempts to maintain utilization near the
3608 low-water mark. As swap utilization gets close to high-water
3609 mark object eviction becomes more aggressive. If utilization is
3610 close to the low-water mark less replacement is done each time.
3612 Defaults are 90% and 95%. If you have a large cache, 5% could be
3613 hundreds of MB. If this is the case you may wish to set these
3614 numbers closer together.
3616 See also cache_swap_high
3619 NAME: cache_swap_high
3620 COMMENT: (percent, 0-100)
3623 LOC: Config.Swap.highWaterMark
3625 The high-water mark for cache object replacement.
3626 Replacement begins when the swap (disk) usage is above the
3627 low-water mark and attempts to maintain utilization near the
3628 low-water mark. As swap utilization gets close to high-water
3629 mark object eviction becomes more aggressive. If utilization is
3630 close to the low-water mark less replacement is done each time.
3632 Defaults are 90% and 95%. If you have a large cache, 5% could be
3633 hundreds of MB. If this is the case you may wish to set these
3634 numbers closer together.
3636 See also cache_swap_low
3641 -----------------------------------------------------------------------------
3648 DEFAULT_DOC: The format definitions squid, common, combined, referrer, useragent are built in.
3652 logformat <name> <format specification>
3654 Defines an access log format.
3656 The <format specification> is a string with embedded % format codes
3658 % format codes all follow the same basic structure where all but
3659 the formatcode is optional. Output strings are automatically escaped
3660 as required according to their context and the output format
3661 modifiers are usually not needed, but can be specified if an explicit
3662 output format is desired.
3664 % ["|[|'|#] [-] [[0]width] [{argument}] formatcode
3666 " output in quoted string format
3667 [ output in squid text log format as used by log_mime_hdrs
3668 # output in URL quoted format
3673 width minimum and/or maximum field width:
3674 [width_min][.width_max]
3675 When minimum starts with 0, the field is zero-padded.
3676 String values exceeding maximum width are truncated.
3678 {arg} argument such as header name etc
3682 % a literal % character
3683 sn Unique sequence number per log line entry
3684 err_code The ID of an error response served by Squid or
3685 a similar internal error identifier.
3686 err_detail Additional err_code-dependent error information.
3687 note The annotation specified by the argument. Also
3688 logs the adaptation meta headers set by the
3689 adaptation_meta configuration parameter.
3690 If no argument given all annotations logged.
3691 The argument may include a separator to use with
3694 By default, multiple note values are separated with ","
3695 and multiple notes are separated with "\r\n".
3696 When logging named notes with %{name}note, the
3697 explicitly configured separator is used between note
3698 values. When logging all notes with %note, the
3699 explicitly configured separator is used between
3700 individual notes. There is currently no way to
3701 specify both value and notes separators when logging
3702 all notes with %note.
3704 Connection related format codes:
3706 >a Client source IP address
3708 >p Client source port
3709 >eui Client source EUI (MAC address, EUI-48 or EUI-64 identifier)
3710 >la Local IP address the client connected to
3711 >lp Local port number the client connected to
3712 >qos Client connection TOS/DSCP value set by Squid
3713 >nfmark Client connection netfilter mark set by Squid
3715 la Local listening IP address the client connection was connected to.
3716 lp Local listening port number the client connection was connected to.
3718 <a Server IP address of the last server or peer connection
3719 <A Server FQDN or peer name
3720 <p Server port number of the last server or peer connection
3721 <la Local IP address of the last server or peer connection
3722 <lp Local port number of the last server or peer connection
3723 <qos Server connection TOS/DSCP value set by Squid
3724 <nfmark Server connection netfilter mark set by Squid
3726 Time related format codes:
3728 ts Seconds since epoch
3729 tu subsecond time (milliseconds)
3730 tl Local time. Optional strftime format argument
3731 default %d/%b/%Y:%H:%M:%S %z
3732 tg GMT time. Optional strftime format argument
3733 default %d/%b/%Y:%H:%M:%S %z
3734 tr Response time (milliseconds)
3735 dt Total time spent making DNS lookups (milliseconds)
3736 tS Approximate master transaction start time in
3737 <full seconds since epoch>.<fractional seconds> format.
3738 Currently, Squid considers the master transaction
3739 started when a complete HTTP request header initiating
3740 the transaction is received from the client. This is
3741 the same value that Squid uses to calculate transaction
3742 response time when logging %tr to access.log. Currently,
3743 Squid uses millisecond resolution for %tS values,
3744 similar to the default access.log "current time" field
3747 Access Control related format codes:
3749 et Tag returned by external acl
3750 ea Log string returned by external acl
3751 un User name (any available)
3752 ul User name from authentication
3753 ue User name from external acl helper
3754 ui User name from ident
3755 us User name from SSL
3756 credentials Client credentials. The exact meaning depends on
3757 the authentication scheme: For Basic authentication,
3758 it is the password; for Digest, the realm sent by the
3759 client; for NTLM and Negotiate, the client challenge
3760 or client credentials prefixed with "YR " or "KK ".
3762 HTTP related format codes:
3766 [http::]rm Request method (GET/POST etc)
3767 [http::]>rm Request method from client
3768 [http::]<rm Request method sent to server or peer
3769 [http::]ru Request URL from client (historic, filtered for logging)
3770 [http::]>ru Request URL from client
3771 [http::]<ru Request URL sent to server or peer
3772 [http::]>rs Request URL scheme from client
3773 [http::]<rs Request URL scheme sent to server or peer
3774 [http::]>rd Request URL domain from client
3775 [http::]>rd Request URL domain sent to server or peer
3776 [http::]>rP Request URL port from client
3777 [http::]<rP Request URL port sent to server or peer
3778 [http::]rp Request URL path excluding hostname
3779 [http::]>rp Request URL path excluding hostname from client
3780 [http::]<rp Request URL path excluding hostname sent to server or peer
3781 [http::]rv Request protocol version
3782 [http::]>rv Request protocol version from client
3783 [http::]<rv Request protocol version sent to server or peer
3785 [http::]>h Original received request header.
3786 Usually differs from the request header sent by
3787 Squid, although most fields are often preserved.
3788 Accepts optional header field name/value filter
3789 argument using name[:[separator]element] format.
3790 [http::]>ha Received request header after adaptation and
3791 redirection (pre-cache REQMOD vectoring point).
3792 Usually differs from the request header sent by
3793 Squid, although most fields are often preserved.
3794 Optional header name argument as for >h
3799 [http::]<Hs HTTP status code received from the next hop
3800 [http::]>Hs HTTP status code sent to the client
3802 [http::]<h Reply header. Optional header name argument
3805 [http::]mt MIME content type
3810 [http::]st Total size of request + reply traffic with client
3811 [http::]>st Total size of request received from client.
3812 Excluding chunked encoding bytes.
3813 [http::]<st Total size of reply sent to client (after adaptation)
3815 [http::]>sh Size of request headers received from client
3816 [http::]<sh Size of reply headers sent to client (after adaptation)
3818 [http::]<sH Reply high offset sent
3819 [http::]<sS Upstream object size
3821 [http::]<bs Number of HTTP-equivalent message body bytes
3822 received from the next hop, excluding chunked
3823 transfer encoding and control messages.
3824 Generated FTP/Gopher listings are treated as
3830 [http::]<pt Peer response time in milliseconds. The timer starts
3831 when the last request byte is sent to the next hop
3832 and stops when the last response byte is received.
3833 [http::]<tt Total server-side time in milliseconds. The timer
3834 starts with the first connect request (or write I/O)
3835 sent to the first selected peer. The timer stops
3836 with the last I/O with the last peer.
3838 Squid handling related format codes:
3840 Ss Squid request status (TCP_MISS etc)
3841 Sh Squid hierarchy status (DEFAULT_PARENT etc)
3843 SSL-related format codes:
3845 ssl::bump_mode SslBump decision for the transaction:
3847 For CONNECT requests that initiated bumping of
3848 a connection and for any request received on
3849 an already bumped connection, Squid logs the
3850 corresponding SslBump mode ("server-first" or
3851 "client-first"). See the ssl_bump option for
3852 more information about these modes.
3854 A "none" token is logged for requests that
3855 triggered "ssl_bump" ACL evaluation matching
3856 either a "none" rule or no rules at all.
3858 In all other cases, a single dash ("-") is
3861 If ICAP is enabled, the following code becomes available (as
3862 well as ICAP log codes documented with the icap_log option):
3864 icap::tt Total ICAP processing time for the HTTP
3865 transaction. The timer ticks when ICAP
3866 ACLs are checked and when ICAP
3867 transaction is in progress.
3869 If adaptation is enabled the following three codes become available:
3871 adapt::<last_h The header of the last ICAP response or
3872 meta-information from the last eCAP
3873 transaction related to the HTTP transaction.
3874 Like <h, accepts an optional header name
3877 adapt::sum_trs Summed adaptation transaction response
3878 times recorded as a comma-separated list in
3879 the order of transaction start time. Each time
3880 value is recorded as an integer number,
3881 representing response time of one or more
3882 adaptation (ICAP or eCAP) transaction in
3883 milliseconds. When a failed transaction is
3884 being retried or repeated, its time is not
3885 logged individually but added to the
3886 replacement (next) transaction. See also:
3889 adapt::all_trs All adaptation transaction response times.
3890 Same as adaptation_strs but response times of
3891 individual transactions are never added
3892 together. Instead, all transaction response
3893 times are recorded individually.
3895 You can prefix adapt::*_trs format codes with adaptation
3896 service name in curly braces to record response time(s) specific
3897 to that service. For example: %{my_service}adapt::sum_trs
3899 If SSL is enabled, the following formating codes become available:
3901 %ssl::>cert_subject The Subject field of the received client
3902 SSL certificate or a dash ('-') if Squid has
3903 received an invalid/malformed certificate or
3904 no certificate at all. Consider encoding the
3905 logged value because Subject often has spaces.
3907 %ssl::>cert_issuer The Issuer field of the received client
3908 SSL certificate or a dash ('-') if Squid has
3909 received an invalid/malformed certificate or
3910 no certificate at all. Consider encoding the
3911 logged value because Issuer often has spaces.
3913 The default formats available (which do not need re-defining) are:
3915 logformat squid %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %[un %Sh/%<a %mt
3916 logformat common %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st %Ss:%Sh
3917 logformat combined %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
3918 logformat referrer %ts.%03tu %>a %{Referer}>h %ru
3919 logformat useragent %>a [%tl] "%{User-Agent}>h"
3921 NOTE: When the log_mime_hdrs directive is set to ON.
3922 The squid, common and combined formats have a safely encoded copy
3923 of the mime headers appended to each line within a pair of brackets.
3925 NOTE: The common and combined formats are not quite true to the Apache definition.
3926 The logs from Squid contain an extra status and hierarchy code appended.
3930 NAME: access_log cache_access_log
3932 LOC: Config.Log.accesslogs
3933 DEFAULT_IF_NONE: daemon:@DEFAULT_ACCESS_LOG@ squid
3935 Configures whether and how Squid logs HTTP and ICP transactions.
3936 If access logging is enabled, a single line is logged for every
3937 matching HTTP or ICP request. The recommended directive formats are:
3939 access_log <module>:<place> [option ...] [acl acl ...]
3940 access_log none [acl acl ...]
3942 The following directive format is accepted but may be deprecated:
3943 access_log <module>:<place> [<logformat name> [acl acl ...]]
3945 In most cases, the first ACL name must not contain the '=' character
3946 and should not be equal to an existing logformat name. You can always
3947 start with an 'all' ACL to work around those restrictions.
3949 Will log to the specified module:place using the specified format (which
3950 must be defined in a logformat directive) those entries which match
3951 ALL the acl's specified (which must be defined in acl clauses).
3952 If no acl is specified, all requests will be logged to this destination.
3954 ===== Available options for the recommended directive format =====
3956 logformat=name Names log line format (either built-in or
3957 defined by a logformat directive). Defaults
3960 buffer-size=64KB Defines approximate buffering limit for log
3961 records (see buffered_logs). Squid should not
3962 keep more than the specified size and, hence,
3963 should flush records before the buffer becomes
3964 full to avoid overflows under normal
3965 conditions (the exact flushing algorithm is
3966 module-dependent though). The on-error option
3967 controls overflow handling.
3969 on-error=die|drop Defines action on unrecoverable errors. The
3970 'drop' action ignores (i.e., does not log)
3971 affected log records. The default 'die' action
3972 kills the affected worker. The drop action
3973 support has not been tested for modules other
3976 ===== Modules Currently available =====
3978 none Do not log any requests matching these ACL.
3979 Do not specify Place or logformat name.
3981 stdio Write each log line to disk immediately at the completion of
3983 Place: the filename and path to be written.
3985 daemon Very similar to stdio. But instead of writing to disk the log
3986 line is passed to a daemon helper for asychronous handling instead.
3987 Place: varies depending on the daemon.
3989 log_file_daemon Place: the file name and path to be written.
3991 syslog To log each request via syslog facility.
3992 Place: The syslog facility and priority level for these entries.
3993 Place Format: facility.priority
3995 where facility could be any of:
3996 authpriv, daemon, local0 ... local7 or user.
3998 And priority could be any of:
3999 err, warning, notice, info, debug.
4001 udp To send each log line as text data to a UDP receiver.
4002 Place: The destination host name or IP and port.
4003 Place Format: //host:port
4005 tcp To send each log line as text data to a TCP receiver.
4006 Lines may be accumulated before sending (see buffered_logs).
4007 Place: The destination host name or IP and port.
4008 Place Format: //host:port
4011 access_log daemon:@DEFAULT_ACCESS_LOG@ squid
4017 LOC: Config.Log.icaplogs
4020 ICAP log files record ICAP transaction summaries, one line per
4023 The icap_log option format is:
4024 icap_log <filepath> [<logformat name> [acl acl ...]]
4025 icap_log none [acl acl ...]]
4027 Please see access_log option documentation for details. The two
4028 kinds of logs share the overall configuration approach and many
4031 ICAP processing of a single HTTP message or transaction may
4032 require multiple ICAP transactions. In such cases, multiple
4033 ICAP transaction log lines will correspond to a single access
4036 ICAP log uses logformat codes that make sense for an ICAP
4037 transaction. Header-related codes are applied to the HTTP header
4038 embedded in an ICAP server response, with the following caveats:
4039 For REQMOD, there is no HTTP response header unless the ICAP
4040 server performed request satisfaction. For RESPMOD, the HTTP
4041 request header is the header sent to the ICAP server. For
4042 OPTIONS, there are no HTTP headers.
4044 The following format codes are also available for ICAP logs:
4046 icap::<A ICAP server IP address. Similar to <A.
4048 icap::<service_name ICAP service name from the icap_service
4049 option in Squid configuration file.
4051 icap::ru ICAP Request-URI. Similar to ru.
4053 icap::rm ICAP request method (REQMOD, RESPMOD, or
4054 OPTIONS). Similar to existing rm.
4056 icap::>st Bytes sent to the ICAP server (TCP payload
4057 only; i.e., what Squid writes to the socket).
4059 icap::<st Bytes received from the ICAP server (TCP
4060 payload only; i.e., what Squid reads from
4063 icap::<bs Number of message body bytes received from the
4064 ICAP server. ICAP message body, if any, usually
4065 includes encapsulated HTTP message headers and
4066 possibly encapsulated HTTP message body. The
4067 HTTP body part is dechunked before its size is
4070 icap::tr Transaction response time (in
4071 milliseconds). The timer starts when
4072 the ICAP transaction is created and
4073 stops when the transaction is completed.
4076 icap::tio Transaction I/O time (in milliseconds). The
4077 timer starts when the first ICAP request
4078 byte is scheduled for sending. The timers
4079 stops when the last byte of the ICAP response
4082 icap::to Transaction outcome: ICAP_ERR* for all
4083 transaction errors, ICAP_OPT for OPTION
4084 transactions, ICAP_ECHO for 204
4085 responses, ICAP_MOD for message
4086 modification, and ICAP_SAT for request
4087 satisfaction. Similar to Ss.
4089 icap::Hs ICAP response status code. Similar to Hs.
4091 icap::>h ICAP request header(s). Similar to >h.
4093 icap::<h ICAP response header(s). Similar to <h.
4095 The default ICAP log format, which can be used without an explicit
4096 definition, is called icap_squid:
4098 logformat icap_squid %ts.%03tu %6icap::tr %>a %icap::to/%03icap::Hs %icap::<size %icap::rm %icap::ru% %un -/%icap::<A -
4100 See also: logformat, log_icap, and %adapt::<last_h
4103 NAME: logfile_daemon
4105 DEFAULT: @DEFAULT_LOGFILED@
4106 LOC: Log::TheConfig.logfile_daemon
4108 Specify the path to the logfile-writing daemon. This daemon is
4109 used to write the access and store logs, if configured.
4111 Squid sends a number of commands to the log daemon:
4112 L<data>\n - logfile data
4117 r<n>\n - set rotate count to <n>
4118 b<n>\n - 1 = buffer output, 0 = don't buffer output
4120 No responses is expected.
4126 Remove this line. Use acls with access_log directives to control access logging
4132 Remove this line. Use acls with icap_log directives to control icap logging
4135 NAME: stats_collection
4137 LOC: Config.accessList.stats_collection
4139 DEFAULT_DOC: Allow logging for all transactions.
4140 COMMENT: allow|deny acl acl...
4142 This options allows you to control which requests gets accounted
4143 in performance counters.
4145 This clause only supports fast acl types.
4146 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4149 NAME: cache_store_log
4152 LOC: Config.Log.store
4154 Logs the activities of the storage manager. Shows which
4155 objects are ejected from the cache, and which objects are
4156 saved and for how long.
4157 There are not really utilities to analyze this data, so you can safely
4158 disable it (the default).
4160 Store log uses modular logging outputs. See access_log for the list
4161 of modules supported.
4164 cache_store_log stdio:@DEFAULT_STORE_LOG@
4165 cache_store_log daemon:@DEFAULT_STORE_LOG@
4168 NAME: cache_swap_state cache_swap_log
4170 LOC: Config.Log.swap
4172 DEFAULT_DOC: Store the journal inside its cache_dir
4174 Location for the cache "swap.state" file. This index file holds
4175 the metadata of objects saved on disk. It is used to rebuild
4176 the cache during startup. Normally this file resides in each
4177 'cache_dir' directory, but you may specify an alternate
4178 pathname here. Note you must give a full filename, not just
4179 a directory. Since this is the index for the whole object
4180 list you CANNOT periodically rotate it!
4182 If %s can be used in the file name it will be replaced with a
4183 a representation of the cache_dir name where each / is replaced
4184 with '.'. This is needed to allow adding/removing cache_dir
4185 lines when cache_swap_log is being used.
4187 If have more than one 'cache_dir', and %s is not used in the name
4188 these swap logs will have names such as:
4194 The numbered extension (which is added automatically)
4195 corresponds to the order of the 'cache_dir' lines in this
4196 configuration file. If you change the order of the 'cache_dir'
4197 lines in this file, these index files will NOT correspond to
4198 the correct 'cache_dir' entry (unless you manually rename
4199 them). We recommend you do NOT use this option. It is
4200 better to keep these index files in each 'cache_dir' directory.
4203 NAME: logfile_rotate
4206 LOC: Config.Log.rotateNumber
4208 Specifies the number of logfile rotations to make when you
4209 type 'squid -k rotate'. The default is 10, which will rotate
4210 with extensions 0 through 9. Setting logfile_rotate to 0 will
4211 disable the file name rotation, but the logfiles are still closed
4212 and re-opened. This will enable you to rename the logfiles
4213 yourself just before sending the rotate signal.
4215 Note, the 'squid -k rotate' command normally sends a USR1
4216 signal to the running squid process. In certain situations
4217 (e.g. on Linux with Async I/O), USR1 is used for other
4218 purposes, so -k rotate uses another signal. It is best to get
4219 in the habit of using 'squid -k rotate' instead of 'kill -USR1
4222 Note, from Squid-3.1 this option is only a default for cache.log,
4223 that log can be rotated separately by using debug_options.
4226 NAME: emulate_httpd_log
4229 Replace this with an access_log directive using the format 'common' or 'combined'.
4232 NAME: log_ip_on_direct
4235 Remove this option from your config. To log server or peer names use %<A in the log format.
4240 DEFAULT: @DEFAULT_MIME_TABLE@
4241 LOC: Config.mimeTablePathname
4243 Path to Squid's icon configuration file.
4245 You shouldn't need to change this, but the default file contains
4246 examples and formatting information if you do.
4252 LOC: Config.onoff.log_mime_hdrs
4255 The Cache can record both the request and the response MIME
4256 headers for each HTTP transaction. The headers are encoded
4257 safely and will appear as two bracketed fields at the end of
4258 the access log (for either the native or httpd-emulated log
4259 formats). To enable this logging set log_mime_hdrs to 'on'.
4265 Replace this with an access_log directive using the format 'useragent'.
4268 NAME: referer_log referrer_log
4271 Replace this with an access_log directive using the format 'referrer'.
4276 DEFAULT: @DEFAULT_PID_FILE@
4277 LOC: Config.pidFilename
4279 A filename to write the process-id to. To disable, enter "none".
4285 Remove this option from your config. To log FQDN use %>A in the log format.
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'.
4303 Use a regular access.log with ACL limiting it to MISS events.
4306 NAME: strip_query_terms
4308 LOC: Config.onoff.strip_query_terms
4311 By default, Squid strips query terms from requested URLs before
4312 logging. This protects your user's privacy and reduces log size.
4314 When investigating HIT/MISS or other caching behaviour you
4315 will need to disable this to see the full URL used by Squid.
4322 LOC: Config.onoff.buffered_logs
4324 Whether to write/send access_log records ASAP or accumulate them and
4325 then write/send them in larger chunks. Buffering may improve
4326 performance because it decreases the number of I/Os. However,
4327 buffering increases the delay before log records become available to
4328 the final recipient (e.g., a disk file or logging daemon) and,
4329 hence, increases the risk of log records loss.
4331 Note that even when buffered_logs are off, Squid may have to buffer
4332 records if it cannot write/send them immediately due to pending I/Os
4333 (e.g., the I/O writing the previous log record) or connectivity loss.
4335 Currently honored by 'daemon' and 'tcp' access_log modules only.
4338 NAME: netdb_filename
4340 DEFAULT: stdio:@DEFAULT_NETDB_FILE@
4341 LOC: Config.netdbFilename
4344 Where Squid stores it's netdb journal.
4345 When enabled this journal preserves netdb state between restarts.
4347 To disable, enter "none".
4351 OPTIONS FOR TROUBLESHOOTING
4352 -----------------------------------------------------------------------------
4357 DEFAULT_IF_NONE: @DEFAULT_CACHE_LOG@
4358 LOC: Debug::cache_log
4360 Squid administrative logging file.
4362 This is where general information about Squid behavior goes. You can
4363 increase the amount of data logged to this file and how often it is
4364 rotated with "debug_options"
4370 DEFAULT_DOC: Log all critical and important messages.
4371 LOC: Debug::debugOptions
4373 Logging options are set as section,level where each source file
4374 is assigned a unique section. Lower levels result in less
4375 output, Full debugging (level 9) can result in a very large
4376 log file, so be careful.
4378 The magic word "ALL" sets debugging levels for all sections.
4379 The default is to run with "ALL,1" to record important warnings.
4381 The rotate=N option can be used to keep more or less of these logs
4382 than would otherwise be kept by logfile_rotate.
4383 For most uses a single log should be enough to monitor current
4384 events affecting Squid.
4389 LOC: Config.coredump_dir
4390 DEFAULT_IF_NONE: none
4391 DEFAULT_DOC: Use the directory from where Squid was started.
4393 By default Squid leaves core files in the directory from where
4394 it was started. If you set 'coredump_dir' to a directory
4395 that exists, Squid will chdir() to that directory at startup
4396 and coredump files will be left there.
4400 # Leave coredumps in the first cache dir
4401 coredump_dir @DEFAULT_SWAP_DIR@
4407 OPTIONS FOR FTP GATEWAYING
4408 -----------------------------------------------------------------------------
4414 LOC: Config.Ftp.anon_user
4416 If you want the anonymous login password to be more informative
4417 (and enable the use of picky FTP servers), set this to something
4418 reasonable for your domain, like wwwuser@somewhere.net
4420 The reason why this is domainless by default is the
4421 request can be made on the behalf of a user in any domain,
4422 depending on how the cache is used.
4423 Some FTP server also validate the email address is valid
4424 (for example perl.com).
4430 LOC: Config.Ftp.passive
4432 If your firewall does not allow Squid to use passive
4433 connections, turn off this option.
4435 Use of ftp_epsv_all option requires this to be ON.
4441 LOC: Config.Ftp.epsv_all
4443 FTP Protocol extensions permit the use of a special "EPSV ALL" command.
4445 NATs may be able to put the connection on a "fast path" through the
4446 translator, as the EPRT command will never be used and therefore,
4447 translation of the data portion of the segments will never be needed.
4449 When a client only expects to do two-way FTP transfers this may be
4451 If squid finds that it must do a three-way FTP transfer after issuing
4452 an EPSV ALL command, the FTP session will fail.
4454 If you have any doubts about this option do not use it.
4455 Squid will nicely attempt all other connection methods.
4457 Requires ftp_passive to be ON (default) for any effect.
4463 LOC: Config.accessList.ftp_epsv
4465 FTP Protocol extensions permit the use of a special "EPSV" command.
4467 NATs may be able to put the connection on a "fast path" through the
4468 translator using EPSV, as the EPRT command will never be used
4469 and therefore, translation of the data portion of the segments
4470 will never be needed.
4472 EPSV is often required to interoperate with FTP servers on IPv6
4473 networks. On the other hand, it may break some IPv4 servers.
4475 By default, EPSV may try EPSV with any FTP server. To fine tune
4476 that decision, you may restrict EPSV to certain clients or servers
4479 ftp_epsv allow|deny al1 acl2 ...
4481 WARNING: Disabling EPSV may cause problems with external NAT and IPv6.
4483 Only fast ACLs are supported.
4484 Requires ftp_passive to be ON (default) for any effect.
4490 LOC: Config.Ftp.eprt
4492 FTP Protocol extensions permit the use of a special "EPRT" command.
4494 This extension provides a protocol neutral alternative to the
4495 IPv4-only PORT command. When supported it enables active FTP data
4496 channels over IPv6 and efficient NAT handling.
4498 Turning this OFF will prevent EPRT being attempted and will skip
4499 straight to using PORT for IPv4 servers.
4501 Some devices are known to not handle this extension correctly and
4502 may result in crashes. Devices which suport EPRT enough to fail
4503 cleanly will result in Squid attempting PORT anyway. This directive
4504 should only be disabled when EPRT results in device failures.
4506 WARNING: Doing so will convert Squid back to the old behavior with all
4507 the related problems with external NAT devices/layers and IPv4-only FTP.
4510 NAME: ftp_sanitycheck
4513 LOC: Config.Ftp.sanitycheck
4515 For security and data integrity reasons Squid by default performs
4516 sanity checks of the addresses of FTP data connections ensure the
4517 data connection is to the requested server. If you need to allow
4518 FTP connections to servers using another IP address for the data
4519 connection turn this off.
4522 NAME: ftp_telnet_protocol
4525 LOC: Config.Ftp.telnet
4527 The FTP protocol is officially defined to use the telnet protocol
4528 as transport channel for the control connection. However, many
4529 implementations are broken and does not respect this aspect of
4532 If you have trouble accessing files with ASCII code 255 in the
4533 path or similar problems involving this ASCII code you can
4534 try setting this directive to off. If that helps, report to the
4535 operator of the FTP server in question that their FTP server
4536 is broken and does not follow the FTP standard.
4540 OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
4541 -----------------------------------------------------------------------------
4546 DEFAULT: @DEFAULT_DISKD@
4547 LOC: Config.Program.diskd
4549 Specify the location of the diskd executable.
4550 Note this is only useful if you have compiled in
4551 diskd as one of the store io modules.
4554 NAME: unlinkd_program
4557 DEFAULT: @DEFAULT_UNLINKD@
4558 LOC: Config.Program.unlinkd
4560 Specify the location of the executable for file deletion process.
4563 NAME: pinger_program
4565 DEFAULT: @DEFAULT_PINGER@
4566 LOC: Config.pinger.program
4569 Specify the location of the executable for the pinger process.
4575 LOC: Config.pinger.enable
4578 Control whether the pinger is active at run-time.
4579 Enables turning ICMP pinger on and off with a simple
4580 squid -k reconfigure.
4585 OPTIONS FOR URL REWRITING
4586 -----------------------------------------------------------------------------
4589 NAME: url_rewrite_program redirect_program
4591 LOC: Config.Program.redirect
4594 Specify the location of the executable URL rewriter to use.
4595 Since they can perform almost any function there isn't one included.
4597 For each requested URL, the rewriter will receive on line with the format
4599 [channel-ID <SP>] URL [<SP> extras]<NL>
4601 See url_rewrite_extras on how to send "extras" with optional values to
4603 After processing the request the helper must reply using the following format:
4605 [channel-ID <SP>] result [<SP> kv-pairs]
4607 The result code can be:
4609 OK status=30N url="..."
4610 Redirect the URL to the one supplied in 'url='.
4611 'status=' is optional and contains the status code to send
4612 the client in Squids HTTP response. It must be one of the
4613 HTTP redirect status codes: 301, 302, 303, 307, 308.
4614 When no status is given Squid will use 302.
4616 OK rewrite-url="..."
4617 Rewrite the URL to the one supplied in 'rewrite-url='.
4618 The new URL is fetched directly by Squid and returned to
4619 the client as the response to its request.
4622 When neither of url= and rewrite-url= are sent Squid does
4626 Do not change the URL.
4629 An internal error occurred in the helper, preventing
4630 a result being identified. The 'message=' key name is
4631 reserved for delivering a log message.
4634 In addition to the above kv-pairs Squid also understands the following
4635 optional kv-pairs received from URL rewriters:
4637 Associates a TAG with the client TCP connection.
4638 The TAG is treated as a regular annotation but persists across
4639 future requests on the client connection rather than just the
4640 current request. A helper may update the TAG during subsequent
4641 requests be returning a new kv-pair.
4643 When using the concurrency= option the protocol is changed by
4644 introducing a query channel tag in front of the request/response.
4645 The query channel tag is a number between 0 and concurrency-1.
4646 This value must be echoed back unchanged to Squid as the first part
4647 of the response relating to its request.
4649 WARNING: URL re-writing ability should be avoided whenever possible.
4650 Use the URL redirect form of response instead.
4652 Re-write creates a difference in the state held by the client
4653 and server. Possibly causing confusion when the server response
4654 contains snippets of its view state. Embeded URLs, response
4655 and content Location headers, etc. are not re-written by this
4658 By default, a URL rewriter is not used.
4661 NAME: url_rewrite_children redirect_children
4662 TYPE: HelperChildConfig
4663 DEFAULT: 20 startup=0 idle=1 concurrency=0
4664 LOC: Config.redirectChildren
4666 The maximum number of redirector processes to spawn. If you limit
4667 it too few Squid will have to wait for them to process a backlog of
4668 URLs, slowing it down. If you allow too many they will use RAM
4669 and other system resources noticably.
4671 The startup= and idle= options allow some measure of skew in your
4676 Sets a minimum of how many processes are to be spawned when Squid
4677 starts or reconfigures. When set to zero the first request will
4678 cause spawning of the first child process to handle it.
4680 Starting too few will cause an initial slowdown in traffic as Squid
4681 attempts to simultaneously spawn enough processes to cope.
4685 Sets a minimum of how many processes Squid is to try and keep available
4686 at all times. When traffic begins to rise above what the existing
4687 processes can handle this many more will be spawned up to the maximum
4688 configured. A minimum setting of 1 is required.
4692 The number of requests each redirector helper can handle in
4693 parallel. Defaults to 0 which indicates the redirector
4694 is a old-style single threaded redirector.
4696 When this directive is set to a value >= 1 then the protocol
4697 used to communicate with the helper is modified to include
4698 an ID in front of the request/response. The ID from the request
4699 must be echoed back with the response to that request.
4702 NAME: url_rewrite_host_header redirect_rewrites_host_header
4705 LOC: Config.onoff.redir_rewrites_host
4707 To preserve same-origin security policies in browsers and
4708 prevent Host: header forgery by redirectors Squid rewrites
4709 any Host: header in redirected requests.
4711 If you are running an accelerator this may not be a wanted
4712 effect of a redirector. This directive enables you disable
4713 Host: alteration in reverse-proxy traffic.
4715 WARNING: Entries are cached on the result of the URL rewriting
4716 process, so be careful if you have domain-virtual hosts.
4718 WARNING: Squid and other software verifies the URL and Host
4719 are matching, so be careful not to relay through other proxies
4720 or inspecting firewalls with this disabled.
4723 NAME: url_rewrite_access redirector_access
4726 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
4727 LOC: Config.accessList.redirector
4729 If defined, this access list specifies which requests are
4730 sent to the redirector processes.
4732 This clause supports both fast and slow acl types.
4733 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4736 NAME: url_rewrite_bypass redirector_bypass
4738 LOC: Config.onoff.redirector_bypass
4741 When this is 'on', a request will not go through the
4742 redirector if all the helpers are busy. If this is 'off'
4743 and the redirector queue grows too large, Squid will exit
4744 with a FATAL error and ask you to increase the number of
4745 redirectors. You should only enable this if the redirectors
4746 are not critical to your caching system. If you use
4747 redirectors for access control, and you enable this option,
4748 users may have access to pages they should not
4749 be allowed to request.
4752 NAME: url_rewrite_extras
4753 TYPE: TokenOrQuotedString
4754 LOC: Config.redirector_extras
4755 DEFAULT: "%>a/%>A %un %>rm myip=%la myport=%lp"
4757 Specifies a string to be append to request line format for the
4758 rewriter helper. "Quoted" format values may contain spaces and
4759 logformat %macros. In theory, any logformat %macro can be used.
4760 In practice, a %macro expands as a dash (-) if the helper request is
4761 sent before the required macro information is available to Squid.
4765 OPTIONS FOR STORE ID
4766 -----------------------------------------------------------------------------
4769 NAME: store_id_program storeurl_rewrite_program
4771 LOC: Config.Program.store_id
4774 Specify the location of the executable StoreID helper to use.
4775 Since they can perform almost any function there isn't one included.
4777 For each requested URL, the helper will receive one line with the format
4779 [channel-ID <SP>] URL [<SP> extras]<NL>
4782 After processing the request the helper must reply using the following format:
4784 [channel-ID <SP>] result [<SP> kv-pairs]
4786 The result code can be:
4789 Use the StoreID supplied in 'store-id='.
4792 The default is to use HTTP request URL as the store ID.
4795 An internal error occured in the helper, preventing
4796 a result being identified.
4798 In addition to the above kv-pairs Squid also understands the following
4799 optional kv-pairs received from URL rewriters:
4801 Associates a TAG with the client TCP connection.
4802 Please see url_rewrite_program related documentation for this
4805 Helper programs should be prepared to receive and possibly ignore
4806 additional whitespace-separated tokens on each input line.
4808 When using the concurrency= option the protocol is changed by
4809 introducing a query channel tag in front of the request/response.
4810 The query channel tag is a number between 0 and concurrency-1.
4811 This value must be echoed back unchanged to Squid as the first part
4812 of the response relating to its request.
4814 NOTE: when using StoreID refresh_pattern will apply to the StoreID
4815 returned from the helper and not the URL.
4817 WARNING: Wrong StoreID value returned by a careless helper may result
4818 in the wrong cached response returned to the user.
4820 By default, a StoreID helper is not used.
4823 NAME: store_id_extras
4824 TYPE: TokenOrQuotedString
4825 LOC: Config.storeId_extras
4826 DEFAULT: "%>a/%>A %un %>rm myip=%la myport=%lp"
4828 Specifies a string to be append to request line format for the
4829 StoreId helper. "Quoted" format values may contain spaces and
4830 logformat %macros. In theory, any logformat %macro can be used.
4831 In practice, a %macro expands as a dash (-) if the helper request is
4832 sent before the required macro information is available to Squid.
4835 NAME: store_id_children storeurl_rewrite_children
4836 TYPE: HelperChildConfig
4837 DEFAULT: 20 startup=0 idle=1 concurrency=0
4838 LOC: Config.storeIdChildren
4840 The maximum number of StoreID helper processes to spawn. If you limit
4841 it too few Squid will have to wait for them to process a backlog of
4842 requests, slowing it down. If you allow too many they will use RAM
4843 and other system resources noticably.
4845 The startup= and idle= options allow some measure of skew in your
4850 Sets a minimum of how many processes are to be spawned when Squid
4851 starts or reconfigures. When set to zero the first request will
4852 cause spawning of the first child process to handle it.
4854 Starting too few will cause an initial slowdown in traffic as Squid
4855 attempts to simultaneously spawn enough processes to cope.
4859 Sets a minimum of how many processes Squid is to try and keep available
4860 at all times. When traffic begins to rise above what the existing
4861 processes can handle this many more will be spawned up to the maximum
4862 configured. A minimum setting of 1 is required.
4866 The number of requests each storeID helper can handle in
4867 parallel. Defaults to 0 which indicates the helper
4868 is a old-style single threaded program.
4870 When this directive is set to a value >= 1 then the protocol
4871 used to communicate with the helper is modified to include
4872 an ID in front of the request/response. The ID from the request
4873 must be echoed back with the response to that request.
4876 NAME: store_id_access storeurl_rewrite_access
4879 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
4880 LOC: Config.accessList.store_id
4882 If defined, this access list specifies which requests are
4883 sent to the StoreID processes. By default all requests
4886 This clause supports both fast and slow acl types.
4887 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4890 NAME: store_id_bypass storeurl_rewrite_bypass
4892 LOC: Config.onoff.store_id_bypass
4895 When this is 'on', a request will not go through the
4896 helper if all helpers are busy. If this is 'off'
4897 and the helper queue grows too large, Squid will exit
4898 with a FATAL error and ask you to increase the number of
4899 helpers. You should only enable this if the helperss
4900 are not critical to your caching system. If you use
4901 helpers for critical caching components, and you enable this
4902 option, users may not get objects from cache.
4906 OPTIONS FOR TUNING THE CACHE
4907 -----------------------------------------------------------------------------
4910 NAME: cache no_cache
4913 DEFAULT_DOC: By default, this directive is unused and has no effect.
4914 LOC: Config.accessList.noCache
4916 Requests denied by this directive will not be served from the cache
4917 and their responses will not be stored in the cache. This directive
4918 has no effect on other transactions and on already cached responses.
4920 This clause supports both fast and slow acl types.
4921 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4923 This and the two other similar caching directives listed below are
4924 checked at different transaction processing stages, have different
4925 access to response information, affect different cache operations,
4926 and differ in slow ACLs support:
4928 * cache: Checked before Squid makes a hit/miss determination.
4929 No access to reply information!
4930 Denies both serving a hit and storing a miss.
4931 Supports both fast and slow ACLs.
4932 * send_hit: Checked after a hit was detected.
4933 Has access to reply (hit) information.
4934 Denies serving a hit only.
4935 Supports fast ACLs only.
4936 * store_miss: Checked before storing a cachable miss.
4937 Has access to reply (miss) information.
4938 Denies storing a miss only.
4939 Supports fast ACLs only.
4941 If you are not sure which of the three directives to use, apply the
4942 following decision logic:
4944 * If your ACL(s) are of slow type _and_ need response info, redesign.
4945 Squid does not support that particular combination at this time.
4947 * If your directive ACL(s) are of slow type, use "cache"; and/or
4948 * if your directive ACL(s) need no response info, use "cache".
4950 * If you do not want the response cached, use store_miss; and/or
4951 * if you do not want a hit on a cached response, use send_hit.
4957 DEFAULT_DOC: By default, this directive is unused and has no effect.
4958 LOC: Config.accessList.sendHit
4960 Responses denied by this directive will not be served from the cache
4961 (but may still be cached, see store_miss). This directive has no
4962 effect on the responses it allows and on the cached objects.
4964 Please see the "cache" directive for a summary of differences among
4965 store_miss, send_hit, and cache directives.
4967 Unlike the "cache" directive, send_hit only supports fast acl
4968 types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4972 # apply custom Store ID mapping to some URLs
4973 acl MapMe dstdomain .c.example.com
4974 store_id_program ...
4975 store_id_access allow MapMe
4977 # but prevent caching of special responses
4978 # such as 302 redirects that cause StoreID loops
4979 acl Ordinary http_status 200-299
4980 store_miss deny MapMe !Ordinary
4982 # and do not serve any previously stored special responses
4983 # from the cache (in case they were already cached before
4984 # the above store_miss rule was in effect).
4985 send_hit deny MapMe !Ordinary
4991 DEFAULT_DOC: By default, this directive is unused and has no effect.
4992 LOC: Config.accessList.storeMiss
4994 Responses denied by this directive will not be cached (but may still
4995 be served from the cache, see send_hit). This directive has no
4996 effect on the responses it allows and on the already cached responses.
4998 Please see the "cache" directive for a summary of differences among
4999 store_miss, send_hit, and cache directives. See the
5000 send_hit directive for a usage example.
5002 Unlike the "cache" directive, store_miss only supports fast acl
5003 types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5009 LOC: Config.maxStale
5012 This option puts an upper limit on how stale content Squid
5013 will serve from the cache if cache validation fails.
5014 Can be overriden by the refresh_pattern max-stale option.
5017 NAME: refresh_pattern
5018 TYPE: refreshpattern
5022 usage: refresh_pattern [-i] regex min percent max [options]
5024 By default, regular expressions are CASE-SENSITIVE. To make
5025 them case-insensitive, use the -i option.
5027 'Min' is the time (in minutes) an object without an explicit
5028 expiry time should be considered fresh. The recommended
5029 value is 0, any higher values may cause dynamic applications
5030 to be erroneously cached unless the application designer
5031 has taken the appropriate actions.
5033 'Percent' is a percentage of the objects age (time since last
5034 modification age) an object without explicit expiry time
5035 will be considered fresh.
5037 'Max' is an upper limit on how long objects without an explicit
5038 expiry time will be considered fresh.
5040 options: override-expire
5045 ignore-must-revalidate
5052 override-expire enforces min age even if the server
5053 sent an explicit expiry time (e.g., with the
5054 Expires: header or Cache-Control: max-age). Doing this
5055 VIOLATES the HTTP standard. Enabling this feature
5056 could make you liable for problems which it causes.
5058 Note: override-expire does not enforce staleness - it only extends
5059 freshness / min. If the server returns a Expires time which
5060 is longer than your max time, Squid will still consider
5061 the object fresh for that period of time.
5063 override-lastmod enforces min age even on objects
5064 that were modified recently.
5066 reload-into-ims changes a client no-cache or ``reload''
5067 request for a cached entry into a conditional request using
5068 If-Modified-Since and/or If-None-Match headers, provided the
5069 cached entry has a Last-Modified and/or a strong ETag header.
5070 Doing this VIOLATES the HTTP standard. Enabling this feature
5071 could make you liable for problems which it causes.
5073 ignore-reload ignores a client no-cache or ``reload''
5074 header. Doing this VIOLATES the HTTP standard. Enabling
5075 this feature could make you liable for problems which
5078 ignore-no-store ignores any ``Cache-control: no-store''
5079 headers received from a server. Doing this VIOLATES
5080 the HTTP standard. Enabling this feature could make you
5081 liable for problems which it causes.
5083 ignore-must-revalidate ignores any ``Cache-Control: must-revalidate``
5084 headers received from a server. Doing this VIOLATES
5085 the HTTP standard. Enabling this feature could make you
5086 liable for problems which it causes.
5088 ignore-private ignores any ``Cache-control: private''
5089 headers received from a server. Doing this VIOLATES
5090 the HTTP standard. Enabling this feature could make you
5091 liable for problems which it causes.
5093 ignore-auth caches responses to requests with authorization,
5094 as if the originserver had sent ``Cache-control: public''
5095 in the response header. Doing this VIOLATES the HTTP standard.
5096 Enabling this feature could make you liable for problems which
5099 refresh-ims causes squid to contact the origin server
5100 when a client issues an If-Modified-Since request. This
5101 ensures that the client will receive an updated version
5102 if one is available.
5104 store-stale stores responses even if they don't have explicit
5105 freshness or a validator (i.e., Last-Modified or an ETag)
5106 present, or if they're already stale. By default, Squid will
5107 not cache such responses because they usually can't be
5108 reused. Note that such responses will be stale by default.
5110 max-stale=NN provide a maximum staleness factor. Squid won't
5111 serve objects more stale than this even if it failed to
5112 validate the object. Default: use the max_stale global limit.
5114 Basically a cached object is:
5116 FRESH if expires < now, else STALE
5118 FRESH if lm-factor < percent, else STALE
5122 The refresh_pattern lines are checked in the order listed here.
5123 The first entry which matches is used. If none of the entries
5124 match the default will be used.
5126 Note, you must uncomment all the default lines if you want
5127 to change one. The default setting is only active if none is
5133 # Add any of your own refresh_pattern entries above these.
5135 refresh_pattern ^ftp: 1440 20% 10080
5136 refresh_pattern ^gopher: 1440 0% 1440
5137 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0
5138 refresh_pattern . 0 20% 4320
5142 NAME: quick_abort_min
5146 LOC: Config.quickAbort.min
5149 NAME: quick_abort_max
5153 LOC: Config.quickAbort.max
5156 NAME: quick_abort_pct
5160 LOC: Config.quickAbort.pct
5162 The cache by default continues downloading aborted requests
5163 which are almost completed (less than 16 KB remaining). This
5164 may be undesirable on slow (e.g. SLIP) links and/or very busy
5165 caches. Impatient users may tie up file descriptors and
5166 bandwidth by repeatedly requesting and immediately aborting
5169 When the user aborts a request, Squid will check the
5170 quick_abort values to the amount of data transferred until
5173 If the transfer has less than 'quick_abort_min' KB remaining,
5174 it will finish the retrieval.
5176 If the transfer has more than 'quick_abort_max' KB remaining,
5177 it will abort the retrieval.
5179 If more than 'quick_abort_pct' of the transfer has completed,
5180 it will finish the retrieval.
5182 If you do not want any retrieval to continue after the client
5183 has aborted, set both 'quick_abort_min' and 'quick_abort_max'
5186 If you want retrievals to always continue if they are being
5187 cached set 'quick_abort_min' to '-1 KB'.
5190 NAME: read_ahead_gap
5191 COMMENT: buffer-size
5193 LOC: Config.readAheadGap
5196 The amount of data the cache will buffer ahead of what has been
5197 sent to the client when retrieving an object from another server.
5201 IFDEF: USE_HTTP_VIOLATIONS
5204 LOC: Config.negativeTtl
5207 Set the Default Time-to-Live (TTL) for failed requests.
5208 Certain types of failures (such as "connection refused" and
5209 "404 Not Found") are able to be negatively-cached for a short time.
5210 Modern web servers should provide Expires: header, however if they
5211 do not this can provide a minimum TTL.
5212 The default is not to cache errors with unknown expiry details.
5214 Note that this is different from negative caching of DNS lookups.
5216 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5217 this feature could make you liable for problems which it
5221 NAME: positive_dns_ttl
5224 LOC: Config.positiveDnsTtl
5227 Upper limit on how long Squid will cache positive DNS responses.
5228 Default is 6 hours (360 minutes). This directive must be set
5229 larger than negative_dns_ttl.
5232 NAME: negative_dns_ttl
5235 LOC: Config.negativeDnsTtl
5238 Time-to-Live (TTL) for negative caching of failed DNS lookups.
5239 This also sets the lower cache limit on positive lookups.
5240 Minimum value is 1 second, and it is not recommendable to go
5241 much below 10 seconds.
5244 NAME: range_offset_limit
5245 COMMENT: size [acl acl...]
5247 LOC: Config.rangeOffsetLimit
5250 usage: (size) [units] [[!]aclname]
5252 Sets an upper limit on how far (number of bytes) into the file
5253 a Range request may be to cause Squid to prefetch the whole file.
5254 If beyond this limit, Squid forwards the Range request as it is and
5255 the result is NOT cached.
5257 This is to stop a far ahead range request (lets say start at 17MB)
5258 from making Squid fetch the whole object up to that point before
5259 sending anything to the client.
5261 Multiple range_offset_limit lines may be specified, and they will
5262 be searched from top to bottom on each request until a match is found.
5263 The first match found will be used. If no line matches a request, the
5264 default limit of 0 bytes will be used.
5266 'size' is the limit specified as a number of units.
5268 'units' specifies whether to use bytes, KB, MB, etc.
5269 If no units are specified bytes are assumed.
5271 A size of 0 causes Squid to never fetch more than the
5272 client requested. (default)
5274 A size of 'none' causes Squid to always fetch the object from the
5275 beginning so it may cache the result. (2.0 style)
5277 'aclname' is the name of a defined ACL.
5279 NP: Using 'none' as the byte value here will override any quick_abort settings
5280 that may otherwise apply to the range request. The range request will
5281 be fully fetched from start to finish regardless of the client
5282 actions. This affects bandwidth usage.
5285 NAME: minimum_expiry_time
5288 LOC: Config.minimum_expiry_time
5291 The minimum caching time according to (Expires - Date)
5292 headers Squid honors if the object can't be revalidated.
5293 The default is 60 seconds.
5295 In reverse proxy environments it might be desirable to honor
5296 shorter object lifetimes. It is most likely better to make
5297 your server return a meaningful Last-Modified header however.
5299 In ESI environments where page fragments often have short
5300 lifetimes, this will often be best set to 0.
5303 NAME: store_avg_object_size
5307 LOC: Config.Store.avgObjectSize
5309 Average object size, used to estimate number of objects your
5310 cache can hold. The default is 13 KB.
5312 This is used to pre-seed the cache index memory allocation to
5313 reduce expensive reallocate operations while handling clients
5314 traffic. Too-large values may result in memory allocation during
5315 peak traffic, too-small values will result in wasted memory.
5317 Check the cache manager 'info' report metrics for the real
5318 object sizes seen by your Squid before tuning this.
5321 NAME: store_objects_per_bucket
5324 LOC: Config.Store.objectsPerBucket
5326 Target number of objects per bucket in the store hash table.
5327 Lowering this value increases the total number of buckets and
5328 also the storage maintenance rate. The default is 20.
5333 -----------------------------------------------------------------------------
5336 NAME: request_header_max_size
5340 LOC: Config.maxRequestHeaderSize
5342 This specifies the maximum size for HTTP headers in a request.
5343 Request headers are usually relatively small (about 512 bytes).
5344 Placing a limit on the request header size will catch certain
5345 bugs (for example with persistent connections) and possibly
5346 buffer-overflow or denial-of-service attacks.
5349 NAME: reply_header_max_size
5353 LOC: Config.maxReplyHeaderSize
5355 This specifies the maximum size for HTTP headers in a reply.
5356 Reply headers are usually relatively small (about 512 bytes).
5357 Placing a limit on the reply header size will catch certain
5358 bugs (for example with persistent connections) and possibly
5359 buffer-overflow or denial-of-service attacks.
5362 NAME: request_body_max_size
5366 DEFAULT_DOC: No limit.
5367 LOC: Config.maxRequestBodySize
5369 This specifies the maximum size for an HTTP request body.
5370 In other words, the maximum size of a PUT/POST request.
5371 A user who attempts to send a request with a body larger
5372 than this limit receives an "Invalid Request" error message.
5373 If you set this parameter to a zero (the default), there will
5374 be no limit imposed.
5376 See also client_request_buffer_max_size for an alternative
5377 limitation on client uploads which can be configured.
5380 NAME: client_request_buffer_max_size
5384 LOC: Config.maxRequestBufferSize
5386 This specifies the maximum buffer size of a client request.
5387 It prevents squid eating too much memory when somebody uploads
5391 NAME: chunked_request_body_max_size
5395 LOC: Config.maxChunkedRequestBodySize
5397 A broken or confused HTTP/1.1 client may send a chunked HTTP
5398 request to Squid. Squid does not have full support for that
5399 feature yet. To cope with such requests, Squid buffers the
5400 entire request and then dechunks request body to create a
5401 plain HTTP/1.0 request with a known content length. The plain
5402 request is then used by the rest of Squid code as usual.
5404 The option value specifies the maximum size of the buffer used
5405 to hold the request before the conversion. If the chunked
5406 request size exceeds the specified limit, the conversion
5407 fails, and the client receives an "unsupported request" error,
5408 as if dechunking was disabled.
5410 Dechunking is enabled by default. To disable conversion of
5411 chunked requests, set the maximum to zero.
5413 Request dechunking feature and this option in particular are a
5414 temporary hack. When chunking requests and responses are fully
5415 supported, there will be no need to buffer a chunked request.
5419 IFDEF: USE_HTTP_VIOLATIONS
5422 DEFAULT_DOC: Obey RFC 2616.
5423 LOC: Config.accessList.brokenPosts
5425 A list of ACL elements which, if matched, causes Squid to send
5426 an extra CRLF pair after the body of a PUT/POST request.
5428 Some HTTP servers has broken implementations of PUT/POST,
5429 and rely on an extra CRLF pair sent by some WWW clients.
5431 Quote from RFC2616 section 4.1 on this matter:
5433 Note: certain buggy HTTP/1.0 client implementations generate an
5434 extra CRLF's after a POST request. To restate what is explicitly
5435 forbidden by the BNF, an HTTP/1.1 client must not preface or follow
5436 a request with an extra CRLF.
5438 This clause only supports fast acl types.
5439 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5442 acl buggy_server url_regex ^http://....
5443 broken_posts allow buggy_server
5446 NAME: adaptation_uses_indirect_client icap_uses_indirect_client
5449 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_ADAPTATION
5451 LOC: Adaptation::Config::use_indirect_client
5453 Controls whether the indirect client IP address (instead of the direct
5454 client IP address) is passed to adaptation services.
5456 See also: follow_x_forwarded_for adaptation_send_client_ip
5460 IFDEF: USE_HTTP_VIOLATIONS
5464 LOC: Config.onoff.via
5466 If set (default), Squid will include a Via header in requests and
5467 replies as required by RFC2616.
5473 LOC: Config.onoff.ie_refresh
5476 Microsoft Internet Explorer up until version 5.5 Service
5477 Pack 1 has an issue with transparent proxies, wherein it
5478 is impossible to force a refresh. Turning this on provides
5479 a partial fix to the problem, by causing all IMS-REFRESH
5480 requests from older IE versions to check the origin server
5481 for fresh content. This reduces hit ratio by some amount
5482 (~10% in my experience), but allows users to actually get
5483 fresh content when they want it. Note because Squid
5484 cannot tell if the user is using 5.5 or 5.5SP1, the behavior
5485 of 5.5 is unchanged from old versions of Squid (i.e. a
5486 forced refresh is impossible). Newer versions of IE will,
5487 hopefully, continue to have the new behavior and will be
5488 handled based on that assumption. This option defaults to
5489 the old Squid behavior, which is better for hit ratios but
5490 worse for clients using IE, if they need to be able to
5491 force fresh content.
5494 NAME: vary_ignore_expire
5497 LOC: Config.onoff.vary_ignore_expire
5500 Many HTTP servers supporting Vary gives such objects
5501 immediate expiry time with no cache-control header
5502 when requested by a HTTP/1.0 client. This option
5503 enables Squid to ignore such expiry times until
5504 HTTP/1.1 is fully implemented.
5506 WARNING: If turned on this may eventually cause some
5507 varying objects not intended for caching to get cached.
5510 NAME: request_entities
5512 LOC: Config.onoff.request_entities
5515 Squid defaults to deny GET and HEAD requests with request entities,
5516 as the meaning of such requests are undefined in the HTTP standard
5517 even if not explicitly forbidden.
5519 Set this directive to on if you have clients which insists
5520 on sending request entities in GET or HEAD requests. But be warned
5521 that there is server software (both proxies and web servers) which
5522 can fail to properly process this kind of request which may make you
5523 vulnerable to cache pollution attacks if enabled.
5526 NAME: request_header_access
5527 IFDEF: USE_HTTP_VIOLATIONS
5528 TYPE: http_header_access
5529 LOC: Config.request_header_access
5531 DEFAULT_DOC: No limits.
5533 Usage: request_header_access header_name allow|deny [!]aclname ...
5535 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5536 this feature could make you liable for problems which it
5539 This option replaces the old 'anonymize_headers' and the
5540 older 'http_anonymizer' option with something that is much
5541 more configurable. A list of ACLs for each header name allows
5542 removal of specific header fields under specific conditions.
5544 This option only applies to outgoing HTTP request headers (i.e.,
5545 headers sent by Squid to the next HTTP hop such as a cache peer
5546 or an origin server). The option has no effect during cache hit
5547 detection. The equivalent adaptation vectoring point in ICAP
5548 terminology is post-cache REQMOD.
5550 The option is applied to individual outgoing request header
5551 fields. For each request header field F, Squid uses the first
5552 qualifying sets of request_header_access rules:
5554 1. Rules with header_name equal to F's name.
5555 2. Rules with header_name 'Other', provided F's name is not
5556 on the hard-coded list of commonly used HTTP header names.
5557 3. Rules with header_name 'All'.
5559 Within that qualifying rule set, rule ACLs are checked as usual.
5560 If ACLs of an "allow" rule match, the header field is allowed to
5561 go through as is. If ACLs of a "deny" rule match, the header is
5562 removed and request_header_replace is then checked to identify
5563 if the removed header has a replacement. If no rules within the
5564 set have matching ACLs, the header field is left as is.
5566 For example, to achieve the same behavior as the old
5567 'http_anonymizer standard' option, you should use:
5569 request_header_access From deny all
5570 request_header_access Referer deny all
5571 request_header_access User-Agent deny all
5573 Or, to reproduce the old 'http_anonymizer paranoid' feature
5576 request_header_access Authorization allow all
5577 request_header_access Proxy-Authorization allow all
5578 request_header_access Cache-Control allow all
5579 request_header_access Content-Length allow all
5580 request_header_access Content-Type allow all
5581 request_header_access Date allow all
5582 request_header_access Host allow all
5583 request_header_access If-Modified-Since allow all
5584 request_header_access Pragma allow all
5585 request_header_access Accept allow all
5586 request_header_access Accept-Charset allow all
5587 request_header_access Accept-Encoding allow all
5588 request_header_access Accept-Language allow all
5589 request_header_access Connection allow all
5590 request_header_access All deny all
5592 HTTP reply headers are controlled with the reply_header_access directive.
5594 By default, all headers are allowed (no anonymizing is performed).
5597 NAME: reply_header_access
5598 IFDEF: USE_HTTP_VIOLATIONS
5599 TYPE: http_header_access
5600 LOC: Config.reply_header_access
5602 DEFAULT_DOC: No limits.
5604 Usage: reply_header_access header_name allow|deny [!]aclname ...
5606 WARNING: Doing this VIOLATES the HTTP standard. Enabling
5607 this feature could make you liable for problems which it
5610 This option only applies to reply headers, i.e., from the
5611 server to the client.
5613 This is the same as request_header_access, but in the other
5614 direction. Please see request_header_access for detailed
5617 For example, to achieve the same behavior as the old
5618 'http_anonymizer standard' option, you should use:
5620 reply_header_access Server deny all
5621 reply_header_access WWW-Authenticate deny all
5622 reply_header_access Link deny all
5624 Or, to reproduce the old 'http_anonymizer paranoid' feature
5627 reply_header_access Allow allow all
5628 reply_header_access WWW-Authenticate allow all
5629 reply_header_access Proxy-Authenticate allow all
5630 reply_header_access Cache-Control allow all
5631 reply_header_access Content-Encoding allow all
5632 reply_header_access Content-Length allow all
5633 reply_header_access Content-Type allow all
5634 reply_header_access Date allow all
5635 reply_header_access Expires allow all
5636 reply_header_access Last-Modified allow all
5637 reply_header_access Location allow all
5638 reply_header_access Pragma allow all
5639 reply_header_access Content-Language allow all
5640 reply_header_access Retry-After allow all
5641 reply_header_access Title allow all
5642 reply_header_access Content-Disposition allow all
5643 reply_header_access Connection allow all
5644 reply_header_access All deny all
5646 HTTP request headers are controlled with the request_header_access directive.
5648 By default, all headers are allowed (no anonymizing is
5652 NAME: request_header_replace header_replace
5653 IFDEF: USE_HTTP_VIOLATIONS
5654 TYPE: http_header_replace
5655 LOC: Config.request_header_access
5658 Usage: request_header_replace header_name message
5659 Example: request_header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
5661 This option allows you to change the contents of headers
5662 denied with request_header_access above, by replacing them
5663 with some fixed string.
5665 This only applies to request headers, not reply headers.
5667 By default, headers are removed if denied.
5670 NAME: reply_header_replace
5671 IFDEF: USE_HTTP_VIOLATIONS
5672 TYPE: http_header_replace
5673 LOC: Config.reply_header_access
5676 Usage: reply_header_replace header_name message
5677 Example: reply_header_replace Server Foo/1.0
5679 This option allows you to change the contents of headers
5680 denied with reply_header_access above, by replacing them
5681 with some fixed string.
5683 This only applies to reply headers, not request headers.
5685 By default, headers are removed if denied.
5688 NAME: request_header_add
5689 TYPE: HeaderWithAclList
5690 LOC: Config.request_header_add
5693 Usage: request_header_add field-name field-value acl1 [acl2] ...
5694 Example: request_header_add X-Client-CA "CA=%ssl::>cert_issuer" all
5696 This option adds header fields to outgoing HTTP requests (i.e.,
5697 request headers sent by Squid to the next HTTP hop such as a
5698 cache peer or an origin server). The option has no effect during
5699 cache hit detection. The equivalent adaptation vectoring point
5700 in ICAP terminology is post-cache REQMOD.
5702 Field-name is a token specifying an HTTP header name. If a
5703 standard HTTP header name is used, Squid does not check whether
5704 the new header conflicts with any existing headers or violates
5705 HTTP rules. If the request to be modified already contains a
5706 field with the same name, the old field is preserved but the
5707 header field values are not merged.
5709 Field-value is either a token or a quoted string. If quoted
5710 string format is used, then the surrounding quotes are removed
5711 while escape sequences and %macros are processed.
5713 In theory, all of the logformat codes can be used as %macros.
5714 However, unlike logging (which happens at the very end of
5715 transaction lifetime), the transaction may not yet have enough
5716 information to expand a macro when the new header value is needed.
5717 And some information may already be available to Squid but not yet
5718 committed where the macro expansion code can access it (report
5719 such instances!). The macro will be expanded into a single dash
5720 ('-') in such cases. Not all macros have been tested.
5722 One or more Squid ACLs may be specified to restrict header
5723 injection to matching requests. As always in squid.conf, all
5724 ACLs in an option ACL list must be satisfied for the insertion
5725 to happen. The request_header_add option supports fast ACLs
5734 This option used to log custom information about the master
5735 transaction. For example, an admin may configure Squid to log
5736 which "user group" the transaction belongs to, where "user group"
5737 will be determined based on a set of ACLs and not [just]
5738 authentication information.
5739 Values of key/value pairs can be logged using %{key}note macros:
5741 note key value acl ...
5742 logformat myFormat ... %{key}note ...
5745 NAME: relaxed_header_parser
5746 COMMENT: on|off|warn
5748 LOC: Config.onoff.relaxed_header_parser
5751 In the default "on" setting Squid accepts certain forms
5752 of non-compliant HTTP messages where it is unambiguous
5753 what the sending application intended even if the message
5754 is not correctly formatted. The messages is then normalized
5755 to the correct form when forwarded by Squid.
5757 If set to "warn" then a warning will be emitted in cache.log
5758 each time such HTTP error is encountered.
5760 If set to "off" then such HTTP errors will cause the request
5761 or response to be rejected.
5764 NAME: collapsed_forwarding
5767 LOC: Config.onoff.collapsed_forwarding
5770 This option controls whether Squid is allowed to merge multiple
5771 potentially cachable requests for the same URI before Squid knows
5772 whether the response is going to be cachable.
5774 This feature is disabled by default: Enabling collapsed forwarding
5775 needlessly delays forwarding requests that look cachable (when they are
5776 collapsed) but then need to be forwarded individually anyway because
5777 they end up being for uncachable content. However, in some cases, such
5778 as accelleration of highly cachable content with periodic or groupped
5779 expiration times, the gains from collapsing [large volumes of
5780 simultenous refresh requests] outweigh losses from such delays.
5785 -----------------------------------------------------------------------------
5788 NAME: forward_timeout
5791 LOC: Config.Timeout.forward
5794 This parameter specifies how long Squid should at most attempt in
5795 finding a forwarding path for the request before giving up.
5798 NAME: connect_timeout
5801 LOC: Config.Timeout.connect
5804 This parameter specifies how long to wait for the TCP connect to
5805 the requested server or peer to complete before Squid should
5806 attempt to find another path where to forward the request.
5809 NAME: peer_connect_timeout
5812 LOC: Config.Timeout.peer_connect
5815 This parameter specifies how long to wait for a pending TCP
5816 connection to a peer cache. The default is 30 seconds. You
5817 may also set different timeout values for individual neighbors
5818 with the 'connect-timeout' option on a 'cache_peer' line.
5824 LOC: Config.Timeout.read
5827 The read_timeout is applied on server-side connections. After
5828 each successful read(), the timeout will be extended by this
5829 amount. If no data is read again after this amount of time,
5830 the request is aborted and logged with ERR_READ_TIMEOUT. The
5831 default is 15 minutes.
5837 LOC: Config.Timeout.write
5840 This timeout is tracked for all connections that have data
5841 available for writing and are waiting for the socket to become
5842 ready. After each successful write, the timeout is extended by
5843 the configured amount. If Squid has data to write but the
5844 connection is not ready for the configured duration, the
5845 transaction associated with the connection is terminated. The
5846 default is 15 minutes.
5849 NAME: request_timeout
5851 LOC: Config.Timeout.request
5854 How long to wait for complete HTTP request headers after initial
5855 connection establishment.
5858 NAME: client_idle_pconn_timeout persistent_request_timeout
5860 LOC: Config.Timeout.clientIdlePconn
5863 How long to wait for the next HTTP request on a persistent
5864 client connection after the previous request completes.
5867 NAME: client_lifetime
5870 LOC: Config.Timeout.lifetime
5873 The maximum amount of time a client (browser) is allowed to
5874 remain connected to the cache process. This protects the Cache
5875 from having a lot of sockets (and hence file descriptors) tied up
5876 in a CLOSE_WAIT state from remote clients that go away without
5877 properly shutting down (either because of a network failure or
5878 because of a poor client implementation). The default is one
5881 NOTE: The default value is intended to be much larger than any
5882 client would ever need to be connected to your cache. You
5883 should probably change client_lifetime only as a last resort.
5884 If you seem to have many client connections tying up
5885 filedescriptors, we recommend first tuning the read_timeout,
5886 request_timeout, persistent_request_timeout and quick_abort values.
5889 NAME: half_closed_clients
5891 LOC: Config.onoff.half_closed_clients
5894 Some clients may shutdown the sending side of their TCP
5895 connections, while leaving their receiving sides open. Sometimes,
5896 Squid can not tell the difference between a half-closed and a
5897 fully-closed TCP connection.
5899 By default, Squid will immediately close client connections when
5900 read(2) returns "no more data to read."
5902 Change this option to 'on' and Squid will keep open connections
5903 until a read(2) or write(2) on the socket returns an error.
5904 This may show some benefits for reverse proxies. But if not
5905 it is recommended to leave OFF.
5908 NAME: server_idle_pconn_timeout pconn_timeout
5910 LOC: Config.Timeout.serverIdlePconn
5913 Timeout for idle persistent connections to servers and other
5920 LOC: Ident::TheConfig.timeout
5923 Maximum time to wait for IDENT lookups to complete.
5925 If this is too high, and you enabled IDENT lookups from untrusted
5926 users, you might be susceptible to denial-of-service by having
5927 many ident requests going at once.
5930 NAME: shutdown_lifetime
5933 LOC: Config.shutdownLifetime
5936 When SIGTERM or SIGHUP is received, the cache is put into
5937 "shutdown pending" mode until all active sockets are closed.
5938 This value is the lifetime to set for all open descriptors
5939 during shutdown mode. Any active clients after this many
5940 seconds will receive a 'timeout' message.
5944 ADMINISTRATIVE PARAMETERS
5945 -----------------------------------------------------------------------------
5951 LOC: Config.adminEmail
5953 Email-address of local cache manager who will receive
5954 mail if the cache dies. The default is "webmaster".
5960 LOC: Config.EmailFrom
5962 From: email-address for mail sent when the cache dies.
5963 The default is to use 'squid@unique_hostname'.
5965 See also: unique_hostname directive.
5971 LOC: Config.EmailProgram
5973 Email program used to send mail if the cache dies.
5974 The default is "mail". The specified program must comply
5975 with the standard Unix mail syntax:
5976 mail-program recipient < mailfile
5978 Optional command line options can be specified.
5981 NAME: cache_effective_user
5983 DEFAULT: @DEFAULT_CACHE_EFFECTIVE_USER@
5984 LOC: Config.effectiveUser
5986 If you start Squid as root, it will change its effective/real
5987 UID/GID to the user specified below. The default is to change
5988 to UID of @DEFAULT_CACHE_EFFECTIVE_USER@.
5989 see also; cache_effective_group
5992 NAME: cache_effective_group
5995 DEFAULT_DOC: Use system group memberships of the cache_effective_user account
5996 LOC: Config.effectiveGroup
5998 Squid sets the GID to the effective user's default group ID
5999 (taken from the password file) and supplementary group list
6000 from the groups membership.
6002 If you want Squid to run with a specific GID regardless of
6003 the group memberships of the effective user then set this
6004 to the group (or GID) you want Squid to run as. When set
6005 all other group privileges of the effective user are ignored
6006 and only this GID is effective. If Squid is not started as
6007 root the user starting Squid MUST be member of the specified
6010 This option is not recommended by the Squid Team.
6011 Our preference is for administrators to configure a secure
6012 user account for squid with UID/GID matching system policies.
6015 NAME: httpd_suppress_version_string
6019 LOC: Config.onoff.httpd_suppress_version_string
6021 Suppress Squid version string info in HTTP headers and HTML error pages.
6024 NAME: visible_hostname
6026 LOC: Config.visibleHostname
6028 DEFAULT_DOC: Automatically detect the system host name
6030 If you want to present a special hostname in error messages, etc,
6031 define this. Otherwise, the return value of gethostname()
6032 will be used. If you have multiple caches in a cluster and
6033 get errors about IP-forwarding you must set them to have individual
6034 names with this setting.
6037 NAME: unique_hostname
6039 LOC: Config.uniqueHostname
6041 DEFAULT_DOC: Copy the value from visible_hostname
6043 If you want to have multiple machines with the same
6044 'visible_hostname' you must give each machine a different
6045 'unique_hostname' so forwarding loops can be detected.
6048 NAME: hostname_aliases
6050 LOC: Config.hostnameAliases
6053 A list of other DNS names your cache has.
6061 Minimum umask which should be enforced while the proxy
6062 is running, in addition to the umask set at startup.
6064 For a traditional octal representation of umasks, start
6069 OPTIONS FOR THE CACHE REGISTRATION SERVICE
6070 -----------------------------------------------------------------------------
6072 This section contains parameters for the (optional) cache
6073 announcement service. This service is provided to help
6074 cache administrators locate one another in order to join or
6075 create cache hierarchies.
6077 An 'announcement' message is sent (via UDP) to the registration
6078 service by Squid. By default, the announcement message is NOT
6079 SENT unless you enable it with 'announce_period' below.
6081 The announcement message includes your hostname, plus the
6082 following information from this configuration file:
6088 All current information is processed regularly and made
6089 available on the Web at http://www.ircache.net/Cache/Tracker/.
6092 NAME: announce_period
6094 LOC: Config.Announce.period
6096 DEFAULT_DOC: Announcement messages disabled.
6098 This is how frequently to send cache announcements.
6100 To enable announcing your cache, just set an announce period.
6103 announce_period 1 day
6108 DEFAULT: tracker.ircache.net
6109 LOC: Config.Announce.host
6111 Set the hostname where announce registration messages will be sent.
6113 See also announce_port and announce_file
6119 LOC: Config.Announce.file
6121 The contents of this file will be included in the announce
6122 registration messages.
6128 LOC: Config.Announce.port
6130 Set the port where announce registration messages will be sent.
6132 See also announce_host and announce_file
6136 HTTPD-ACCELERATOR OPTIONS
6137 -----------------------------------------------------------------------------
6140 NAME: httpd_accel_surrogate_id
6143 DEFAULT_DOC: visible_hostname is used if no specific ID is set.
6144 LOC: Config.Accel.surrogate_id
6146 Surrogates (http://www.esi.org/architecture_spec_1.0.html)
6147 need an identification token to allow control targeting. Because
6148 a farm of surrogates may all perform the same tasks, they may share
6149 an identification token.
6152 NAME: http_accel_surrogate_remote
6156 LOC: Config.onoff.surrogate_is_remote
6158 Remote surrogates (such as those in a CDN) honour the header
6159 "Surrogate-Control: no-store-remote".
6161 Set this to on to have squid behave as a remote surrogate.
6165 IFDEF: USE_SQUID_ESI
6166 COMMENT: libxml2|expat|custom
6168 LOC: ESIParser::Type
6171 ESI markup is not strictly XML compatible. The custom ESI parser
6172 will give higher performance, but cannot handle non ASCII character
6177 DELAY POOL PARAMETERS
6178 -----------------------------------------------------------------------------
6182 TYPE: delay_pool_count
6184 IFDEF: USE_DELAY_POOLS
6187 This represents the number of delay pools to be used. For example,
6188 if you have one class 2 delay pool and one class 3 delays pool, you
6189 have a total of 2 delay pools.
6191 See also delay_parameters, delay_class, delay_access for pool
6192 configuration details.
6196 TYPE: delay_pool_class
6198 IFDEF: USE_DELAY_POOLS
6201 This defines the class of each delay pool. There must be exactly one
6202 delay_class line for each delay pool. For example, to define two
6203 delay pools, one of class 2 and one of class 3, the settings above
6207 delay_pools 4 # 4 delay pools
6208 delay_class 1 2 # pool 1 is a class 2 pool
6209 delay_class 2 3 # pool 2 is a class 3 pool
6210 delay_class 3 4 # pool 3 is a class 4 pool
6211 delay_class 4 5 # pool 4 is a class 5 pool
6213 The delay pool classes are:
6215 class 1 Everything is limited by a single aggregate
6218 class 2 Everything is limited by a single aggregate
6219 bucket as well as an "individual" bucket chosen
6220 from bits 25 through 32 of the IPv4 address.
6222 class 3 Everything is limited by a single aggregate
6223 bucket as well as a "network" bucket chosen
6224 from bits 17 through 24 of the IP address and a
6225 "individual" bucket chosen from bits 17 through
6226 32 of the IPv4 address.
6228 class 4 Everything in a class 3 delay pool, with an
6229 additional limit on a per user basis. This
6230 only takes effect if the username is established
6231 in advance - by forcing authentication in your
6234 class 5 Requests are grouped according their tag (see
6235 external_acl's tag= reply).
6238 Each pool also requires a delay_parameters directive to configure the pool size
6239 and speed limits used whenever the pool is applied to a request. Along with
6240 a set of delay_access directives to determine when it is used.
6242 NOTE: If an IP address is a.b.c.d
6243 -> bits 25 through 32 are "d"
6244 -> bits 17 through 24 are "c"
6245 -> bits 17 through 32 are "c * 256 + d"
6247 NOTE-2: Due to the use of bitmasks in class 2,3,4 pools they only apply to
6248 IPv4 traffic. Class 1 and 5 pools may be used with IPv6 traffic.
6250 This clause only supports fast acl types.
6251 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6253 See also delay_parameters and delay_access.
6257 TYPE: delay_pool_access
6259 DEFAULT_DOC: Deny using the pool, unless allow rules exist in squid.conf for the pool.
6260 IFDEF: USE_DELAY_POOLS
6263 This is used to determine which delay pool a request falls into.
6265 delay_access is sorted per pool and the matching starts with pool 1,
6266 then pool 2, ..., and finally pool N. The first delay pool where the
6267 request is allowed is selected for the request. If it does not allow
6268 the request to any pool then the request is not delayed (default).
6270 For example, if you want some_big_clients in delay
6271 pool 1 and lotsa_little_clients in delay pool 2:
6273 delay_access 1 allow some_big_clients
6274 delay_access 1 deny all
6275 delay_access 2 allow lotsa_little_clients
6276 delay_access 2 deny all
6277 delay_access 3 allow authenticated_clients
6279 See also delay_parameters and delay_class.
6283 NAME: delay_parameters
6284 TYPE: delay_pool_rates
6286 IFDEF: USE_DELAY_POOLS
6289 This defines the parameters for a delay pool. Each delay pool has
6290 a number of "buckets" associated with it, as explained in the
6291 description of delay_class.
6293 For a class 1 delay pool, the syntax is:
6295 delay_parameters pool aggregate
6297 For a class 2 delay pool:
6299 delay_parameters pool aggregate individual
6301 For a class 3 delay pool:
6303 delay_parameters pool aggregate network individual
6305 For a class 4 delay pool:
6307 delay_parameters pool aggregate network individual user
6309 For a class 5 delay pool:
6311 delay_parameters pool tagrate
6313 The option variables are:
6315 pool a pool number - ie, a number between 1 and the
6316 number specified in delay_pools as used in
6319 aggregate the speed limit parameters for the aggregate bucket
6322 individual the speed limit parameters for the individual
6323 buckets (class 2, 3).
6325 network the speed limit parameters for the network buckets
6328 user the speed limit parameters for the user buckets
6331 tagrate the speed limit parameters for the tag buckets
6334 A pair of delay parameters is written restore/maximum, where restore is
6335 the number of bytes (not bits - modem and network speeds are usually
6336 quoted in bits) per second placed into the bucket, and maximum is the
6337 maximum number of bytes which can be in the bucket at any time.
6339 There must be one delay_parameters line for each delay pool.
6342 For example, if delay pool number 1 is a class 2 delay pool as in the
6343 above example, and is being used to strictly limit each host to 64Kbit/sec
6344 (plus overheads), with no overall limit, the line is:
6346 delay_parameters 1 -1/-1 8000/8000
6348 Note that 8 x 8000 KByte/sec -> 64Kbit/sec.
6350 Note that the figure -1 is used to represent "unlimited".
6353 And, if delay pool number 2 is a class 3 delay pool as in the above
6354 example, and you want to limit it to a total of 256Kbit/sec (strict limit)
6355 with each 8-bit network permitted 64Kbit/sec (strict limit) and each
6356 individual host permitted 4800bit/sec with a bucket maximum size of 64Kbits
6357 to permit a decent web page to be downloaded at a decent speed
6358 (if the network is not being limited due to overuse) but slow down
6359 large downloads more significantly:
6361 delay_parameters 2 32000/32000 8000/8000 600/8000
6363 Note that 8 x 32000 KByte/sec -> 256Kbit/sec.
6364 8 x 8000 KByte/sec -> 64Kbit/sec.
6365 8 x 600 Byte/sec -> 4800bit/sec.
6368 Finally, for a class 4 delay pool as in the example - each user will
6369 be limited to 128Kbits/sec no matter how many workstations they are logged into.:
6371 delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000
6374 See also delay_class and delay_access.
6378 NAME: delay_initial_bucket_level
6379 COMMENT: (percent, 0-100)
6382 IFDEF: USE_DELAY_POOLS
6383 LOC: Config.Delay.initial
6385 The initial bucket percentage is used to determine how much is put
6386 in each bucket when squid starts, is reconfigured, or first notices
6387 a host accessing it (in class 2 and class 3, individual hosts and
6388 networks only have buckets associated with them once they have been
6393 CLIENT DELAY POOL PARAMETERS
6394 -----------------------------------------------------------------------------
6397 NAME: client_delay_pools
6398 TYPE: client_delay_pool_count
6400 IFDEF: USE_DELAY_POOLS
6401 LOC: Config.ClientDelay
6403 This option specifies the number of client delay pools used. It must
6404 preceed other client_delay_* options.
6407 client_delay_pools 2
6409 See also client_delay_parameters and client_delay_access.
6412 NAME: client_delay_initial_bucket_level
6413 COMMENT: (percent, 0-no_limit)
6416 IFDEF: USE_DELAY_POOLS
6417 LOC: Config.ClientDelay.initial
6419 This option determines the initial bucket size as a percentage of
6420 max_bucket_size from client_delay_parameters. Buckets are created
6421 at the time of the "first" connection from the matching IP. Idle
6422 buckets are periodically deleted up.
6424 You can specify more than 100 percent but note that such "oversized"
6425 buckets are not refilled until their size goes down to max_bucket_size
6426 from client_delay_parameters.
6429 client_delay_initial_bucket_level 50
6432 NAME: client_delay_parameters
6433 TYPE: client_delay_pool_rates
6435 IFDEF: USE_DELAY_POOLS
6436 LOC: Config.ClientDelay
6439 This option configures client-side bandwidth limits using the
6442 client_delay_parameters pool speed_limit max_bucket_size
6444 pool is an integer ID used for client_delay_access matching.
6446 speed_limit is bytes added to the bucket per second.
6448 max_bucket_size is the maximum size of a bucket, enforced after any
6449 speed_limit additions.
6451 Please see the delay_parameters option for more information and
6455 client_delay_parameters 1 1024 2048
6456 client_delay_parameters 2 51200 16384
6458 See also client_delay_access.
6462 NAME: client_delay_access
6463 TYPE: client_delay_pool_access
6465 DEFAULT_DOC: Deny use of the pool, unless allow rules exist in squid.conf for the pool.
6466 IFDEF: USE_DELAY_POOLS
6467 LOC: Config.ClientDelay
6469 This option determines the client-side delay pool for the
6472 client_delay_access pool_ID allow|deny acl_name
6474 All client_delay_access options are checked in their pool ID
6475 order, starting with pool 1. The first checked pool with allowed
6476 request is selected for the request. If no ACL matches or there
6477 are no client_delay_access options, the request bandwidth is not
6480 The ACL-selected pool is then used to find the
6481 client_delay_parameters for the request. Client-side pools are
6482 not used to aggregate clients. Clients are always aggregated
6483 based on their source IP addresses (one bucket per source IP).
6485 This clause only supports fast acl types.
6486 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6487 Additionally, only the client TCP connection details are available.
6488 ACLs testing HTTP properties will not work.
6490 Please see delay_access for more examples.
6493 client_delay_access 1 allow low_rate_network
6494 client_delay_access 2 allow vips_network
6497 See also client_delay_parameters and client_delay_pools.
6501 WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS
6502 -----------------------------------------------------------------------------
6507 LOC: Config.Wccp.router
6509 DEFAULT_DOC: WCCP disabled.
6512 Use this option to define your WCCP ``home'' router for
6515 wccp_router supports a single WCCP(v1) router
6517 wccp2_router supports multiple WCCPv2 routers
6519 only one of the two may be used at the same time and defines
6520 which version of WCCP to use.
6524 TYPE: IpAddress_list
6525 LOC: Config.Wccp2.router
6527 DEFAULT_DOC: WCCPv2 disabled.
6530 Use this option to define your WCCP ``home'' router for
6533 wccp_router supports a single WCCP(v1) router
6535 wccp2_router supports multiple WCCPv2 routers
6537 only one of the two may be used at the same time and defines
6538 which version of WCCP to use.
6543 LOC: Config.Wccp.version
6547 This directive is only relevant if you need to set up WCCP(v1)
6548 to some very old and end-of-life Cisco routers. In all other
6549 setups it must be left unset or at the default setting.
6550 It defines an internal version in the WCCP(v1) protocol,
6551 with version 4 being the officially documented protocol.
6553 According to some users, Cisco IOS 11.2 and earlier only
6554 support WCCP version 3. If you're using that or an earlier
6555 version of IOS, you may need to change this value to 3, otherwise
6556 do not specify this parameter.
6559 NAME: wccp2_rebuild_wait
6561 LOC: Config.Wccp2.rebuildwait
6565 If this is enabled Squid will wait for the cache dir rebuild to finish
6566 before sending the first wccp2 HereIAm packet
6569 NAME: wccp2_forwarding_method
6571 LOC: Config.Wccp2.forwarding_method
6575 WCCP2 allows the setting of forwarding methods between the
6576 router/switch and the cache. Valid values are as follows:
6578 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
6579 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
6581 Currently (as of IOS 12.4) cisco routers only support GRE.
6582 Cisco switches only support the L2 redirect assignment method.
6585 NAME: wccp2_return_method
6587 LOC: Config.Wccp2.return_method
6591 WCCP2 allows the setting of return methods between the
6592 router/switch and the cache for packets that the cache
6593 decides not to handle. Valid values are as follows:
6595 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
6596 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
6598 Currently (as of IOS 12.4) cisco routers only support GRE.
6599 Cisco switches only support the L2 redirect assignment.
6601 If the "ip wccp redirect exclude in" command has been
6602 enabled on the cache interface, then it is still safe for
6603 the proxy server to use a l2 redirect method even if this
6604 option is set to GRE.
6607 NAME: wccp2_assignment_method
6609 LOC: Config.Wccp2.assignment_method
6613 WCCP2 allows the setting of methods to assign the WCCP hash
6614 Valid values are as follows:
6616 hash - Hash assignment
6617 mask - Mask assignment
6619 As a general rule, cisco routers support the hash assignment method
6620 and cisco switches support the mask assignment method.
6625 LOC: Config.Wccp2.info
6626 DEFAULT_IF_NONE: standard 0
6627 DEFAULT_DOC: Use the 'web-cache' standard service.
6630 WCCP2 allows for multiple traffic services. There are two
6631 types: "standard" and "dynamic". The standard type defines
6632 one service id - http (id 0). The dynamic service ids can be from
6633 51 to 255 inclusive. In order to use a dynamic service id
6634 one must define the type of traffic to be redirected; this is done
6635 using the wccp2_service_info option.
6637 The "standard" type does not require a wccp2_service_info option,
6638 just specifying the service id will suffice.
6640 MD5 service authentication can be enabled by adding
6641 "password=<password>" to the end of this service declaration.
6645 wccp2_service standard 0 # for the 'web-cache' standard service
6646 wccp2_service dynamic 80 # a dynamic service type which will be
6647 # fleshed out with subsequent options.
6648 wccp2_service standard 0 password=foo
6651 NAME: wccp2_service_info
6652 TYPE: wccp2_service_info
6653 LOC: Config.Wccp2.info
6657 Dynamic WCCPv2 services require further information to define the
6658 traffic you wish to have diverted.
6662 wccp2_service_info <id> protocol=<protocol> flags=<flag>,<flag>..
6663 priority=<priority> ports=<port>,<port>..
6665 The relevant WCCPv2 flags:
6666 + src_ip_hash, dst_ip_hash
6667 + source_port_hash, dst_port_hash
6668 + src_ip_alt_hash, dst_ip_alt_hash
6669 + src_port_alt_hash, dst_port_alt_hash
6672 The port list can be one to eight entries.
6676 wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source
6677 priority=240 ports=80
6679 Note: the service id must have been defined by a previous
6680 'wccp2_service dynamic <id>' entry.
6685 LOC: Config.Wccp2.weight
6689 Each cache server gets assigned a set of the destination
6690 hash proportional to their weight.
6695 LOC: Config.Wccp.address
6697 DEFAULT_DOC: Address selected by the operating system.
6700 Use this option if you require WCCPv2 to use a specific
6703 The default behavior is to not bind to any specific address.
6708 LOC: Config.Wccp2.address
6710 DEFAULT_DOC: Address selected by the operating system.
6713 Use this option if you require WCCP to use a specific
6716 The default behavior is to not bind to any specific address.
6720 PERSISTENT CONNECTION HANDLING
6721 -----------------------------------------------------------------------------
6723 Also see "pconn_timeout" in the TIMEOUTS section
6726 NAME: client_persistent_connections
6728 LOC: Config.onoff.client_pconns
6731 Persistent connection support for clients.
6732 Squid uses persistent connections (when allowed). You can use
6733 this option to disable persistent connections with clients.
6736 NAME: server_persistent_connections
6738 LOC: Config.onoff.server_pconns
6741 Persistent connection support for servers.
6742 Squid uses persistent connections (when allowed). You can use
6743 this option to disable persistent connections with servers.
6746 NAME: persistent_connection_after_error
6748 LOC: Config.onoff.error_pconns
6751 With this directive the use of persistent connections after
6752 HTTP errors can be disabled. Useful if you have clients
6753 who fail to handle errors on persistent connections proper.
6756 NAME: detect_broken_pconn
6758 LOC: Config.onoff.detect_broken_server_pconns
6761 Some servers have been found to incorrectly signal the use
6762 of HTTP/1.0 persistent connections even on replies not
6763 compatible, causing significant delays. This server problem
6764 has mostly been seen on redirects.
6766 By enabling this directive Squid attempts to detect such
6767 broken replies and automatically assume the reply is finished
6768 after 10 seconds timeout.
6772 CACHE DIGEST OPTIONS
6773 -----------------------------------------------------------------------------
6776 NAME: digest_generation
6777 IFDEF: USE_CACHE_DIGESTS
6779 LOC: Config.onoff.digest_generation
6782 This controls whether the server will generate a Cache Digest
6783 of its contents. By default, Cache Digest generation is
6784 enabled if Squid is compiled with --enable-cache-digests defined.
6787 NAME: digest_bits_per_entry
6788 IFDEF: USE_CACHE_DIGESTS
6790 LOC: Config.digest.bits_per_entry
6793 This is the number of bits of the server's Cache Digest which
6794 will be associated with the Digest entry for a given HTTP
6795 Method and URL (public key) combination. The default is 5.
6798 NAME: digest_rebuild_period
6799 IFDEF: USE_CACHE_DIGESTS
6802 LOC: Config.digest.rebuild_period
6805 This is the wait time between Cache Digest rebuilds.
6808 NAME: digest_rewrite_period
6810 IFDEF: USE_CACHE_DIGESTS
6812 LOC: Config.digest.rewrite_period
6815 This is the wait time between Cache Digest writes to
6819 NAME: digest_swapout_chunk_size
6822 IFDEF: USE_CACHE_DIGESTS
6823 LOC: Config.digest.swapout_chunk_size
6826 This is the number of bytes of the Cache Digest to write to
6827 disk at a time. It defaults to 4096 bytes (4KB), the Squid
6831 NAME: digest_rebuild_chunk_percentage
6832 COMMENT: (percent, 0-100)
6833 IFDEF: USE_CACHE_DIGESTS
6835 LOC: Config.digest.rebuild_chunk_percentage
6838 This is the percentage of the Cache Digest to be scanned at a
6839 time. By default it is set to 10% of the Cache Digest.
6844 -----------------------------------------------------------------------------
6849 LOC: Config.Port.snmp
6851 DEFAULT_DOC: SNMP disabled.
6854 The port number where Squid listens for SNMP requests. To enable
6855 SNMP support set this to a suitable port number. Port number
6856 3401 is often used for the Squid SNMP agent. By default it's
6857 set to "0" (disabled)
6865 LOC: Config.accessList.snmp
6867 DEFAULT_DOC: Deny, unless rules exist in squid.conf.
6870 Allowing or denying access to the SNMP port.
6872 All access to the agent is denied by default.
6875 snmp_access allow|deny [!]aclname ...
6877 This clause only supports fast acl types.
6878 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6881 snmp_access allow snmppublic localhost
6882 snmp_access deny all
6885 NAME: snmp_incoming_address
6887 LOC: Config.Addrs.snmp_incoming
6889 DEFAULT_DOC: Accept SNMP packets from all machine interfaces.
6892 Just like 'udp_incoming_address', but for the SNMP port.
6894 snmp_incoming_address is used for the SNMP socket receiving
6895 messages from SNMP agents.
6897 The default snmp_incoming_address is to listen on all
6898 available network interfaces.
6901 NAME: snmp_outgoing_address
6903 LOC: Config.Addrs.snmp_outgoing
6905 DEFAULT_DOC: Use snmp_incoming_address or an address selected by the operating system.
6908 Just like 'udp_outgoing_address', but for the SNMP port.
6910 snmp_outgoing_address is used for SNMP packets returned to SNMP
6913 If snmp_outgoing_address is not set it will use the same socket
6914 as snmp_incoming_address. Only change this if you want to have
6915 SNMP replies sent using another address than where this Squid
6916 listens for SNMP queries.
6918 NOTE, snmp_incoming_address and snmp_outgoing_address can not have
6919 the same value since they both use the same port.
6924 -----------------------------------------------------------------------------
6927 NAME: icp_port udp_port
6930 DEFAULT_DOC: ICP disabled.
6931 LOC: Config.Port.icp
6933 The port number where Squid sends and receives ICP queries to
6934 and from neighbor caches. The standard UDP port for ICP is 3130.
6937 icp_port @DEFAULT_ICP_PORT@
6944 DEFAULT_DOC: HTCP disabled.
6945 LOC: Config.Port.htcp
6947 The port number where Squid sends and receives HTCP queries to
6948 and from neighbor caches. To turn it on you want to set it to
6955 NAME: log_icp_queries
6959 LOC: Config.onoff.log_udp
6961 If set, ICP queries are logged to access.log. You may wish
6962 do disable this if your ICP load is VERY high to speed things
6963 up or to simplify log analysis.
6966 NAME: udp_incoming_address
6968 LOC:Config.Addrs.udp_incoming
6970 DEFAULT_DOC: Accept packets from all machine interfaces.
6972 udp_incoming_address is used for UDP packets received from other
6975 The default behavior is to not bind to any specific address.
6977 Only change this if you want to have all UDP queries received on
6978 a specific interface/address.
6980 NOTE: udp_incoming_address is used by the ICP, HTCP, and DNS
6981 modules. Altering it will affect all of them in the same manner.
6983 see also; udp_outgoing_address
6985 NOTE, udp_incoming_address and udp_outgoing_address can not
6986 have the same value since they both use the same port.
6989 NAME: udp_outgoing_address
6991 LOC: Config.Addrs.udp_outgoing
6993 DEFAULT_DOC: Use udp_incoming_address or an address selected by the operating system.
6995 udp_outgoing_address is used for UDP packets sent out to other
6998 The default behavior is to not bind to any specific address.
7000 Instead it will use the same socket as udp_incoming_address.
7001 Only change this if you want to have UDP queries sent using another
7002 address than where this Squid listens for UDP queries from other
7005 NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS
7006 modules. Altering it will affect all of them in the same manner.
7008 see also; udp_incoming_address
7010 NOTE, udp_incoming_address and udp_outgoing_address can not
7011 have the same value since they both use the same port.
7018 LOC: Config.onoff.icp_hit_stale
7020 If you want to return ICP_HIT for stale cache objects, set this
7021 option to 'on'. If you have sibling relationships with caches
7022 in other administrative domains, this should be 'off'. If you only
7023 have sibling relationships with caches under your control,
7024 it is probably okay to set this to 'on'.
7025 If set to 'on', your siblings should use the option "allow-miss"
7026 on their cache_peer lines for connecting to you.
7029 NAME: minimum_direct_hops
7032 LOC: Config.minDirectHops
7034 If using the ICMP pinging stuff, do direct fetches for sites
7035 which are no more than this many hops away.
7038 NAME: minimum_direct_rtt
7042 LOC: Config.minDirectRtt
7044 If using the ICMP pinging stuff, do direct fetches for sites
7045 which are no more than this many rtt milliseconds away.
7051 LOC: Config.Netdb.low
7053 The low water mark for the ICMP measurement database.
7055 Note: high watermark controlled by netdb_high directive.
7057 These watermarks are counts, not percents. The defaults are
7058 (low) 900 and (high) 1000. When the high water mark is
7059 reached, database entries will be deleted until the low
7066 LOC: Config.Netdb.high
7068 The high water mark for the ICMP measurement database.
7070 Note: low watermark controlled by netdb_low directive.
7072 These watermarks are counts, not percents. The defaults are
7073 (low) 900 and (high) 1000. When the high water mark is
7074 reached, database entries will be deleted until the low
7078 NAME: netdb_ping_period
7080 LOC: Config.Netdb.period
7083 The minimum period for measuring a site. There will be at
7084 least this much delay between successive pings to the same
7085 network. The default is five minutes.
7092 LOC: Config.onoff.query_icmp
7094 If you want to ask your peers to include ICMP data in their ICP
7095 replies, enable this option.
7097 If your peer has configured Squid (during compilation) with
7098 '--enable-icmp' that peer will send ICMP pings to origin server
7099 sites of the URLs it receives. If you enable this option the
7100 ICP replies from that peer will include the ICMP data (if available).
7101 Then, when choosing a parent cache, Squid will choose the parent with
7102 the minimal RTT to the origin server. When this happens, the
7103 hierarchy field of the access.log will be
7104 "CLOSEST_PARENT_MISS". This option is off by default.
7107 NAME: test_reachability
7111 LOC: Config.onoff.test_reachability
7113 When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
7114 instead of ICP_MISS if the target host is NOT in the ICMP
7115 database, or has a zero RTT.
7118 NAME: icp_query_timeout
7121 DEFAULT_DOC: Dynamic detection.
7123 LOC: Config.Timeout.icp_query
7125 Normally Squid will automatically determine an optimal ICP
7126 query timeout value based on the round-trip-time of recent ICP
7127 queries. If you want to override the value determined by
7128 Squid, set this 'icp_query_timeout' to a non-zero value. This
7129 value is specified in MILLISECONDS, so, to use a 2-second
7130 timeout (the old default), you would write:
7132 icp_query_timeout 2000
7135 NAME: maximum_icp_query_timeout
7139 LOC: Config.Timeout.icp_query_max
7141 Normally the ICP query timeout is determined dynamically. But
7142 sometimes it can lead to very large values (say 5 seconds).
7143 Use this option to put an upper limit on the dynamic timeout
7144 value. Do NOT use this option to always use a fixed (instead
7145 of a dynamic) timeout value. To set a fixed timeout see the
7146 'icp_query_timeout' directive.
7149 NAME: minimum_icp_query_timeout
7153 LOC: Config.Timeout.icp_query_min
7155 Normally the ICP query timeout is determined dynamically. But
7156 sometimes it can lead to very small timeouts, even lower than
7157 the normal latency variance on your link due to traffic.
7158 Use this option to put an lower limit on the dynamic timeout
7159 value. Do NOT use this option to always use a fixed (instead
7160 of a dynamic) timeout value. To set a fixed timeout see the
7161 'icp_query_timeout' directive.
7164 NAME: background_ping_rate
7168 LOC: Config.backgroundPingRate
7170 Controls how often the ICP pings are sent to siblings that
7171 have background-ping set.
7175 MULTICAST ICP OPTIONS
7176 -----------------------------------------------------------------------------
7181 LOC: Config.mcast_group_list
7184 This tag specifies a list of multicast groups which your server
7185 should join to receive multicasted ICP queries.
7187 NOTE! Be very careful what you put here! Be sure you
7188 understand the difference between an ICP _query_ and an ICP
7189 _reply_. This option is to be set only if you want to RECEIVE
7190 multicast queries. Do NOT set this option to SEND multicast
7191 ICP (use cache_peer for that). ICP replies are always sent via
7192 unicast, so this option does not affect whether or not you will
7193 receive replies from multicast group members.
7195 You must be very careful to NOT use a multicast address which
7196 is already in use by another group of caches.
7198 If you are unsure about multicast, please read the Multicast
7199 chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
7201 Usage: mcast_groups 239.128.16.128 224.0.1.20
7203 By default, Squid doesn't listen on any multicast groups.
7206 NAME: mcast_miss_addr
7207 IFDEF: MULTICAST_MISS_STREAM
7209 LOC: Config.mcast_miss.addr
7211 DEFAULT_DOC: disabled.
7213 If you enable this option, every "cache miss" URL will
7214 be sent out on the specified multicast address.
7216 Do not enable this option unless you are are absolutely
7217 certain you understand what you are doing.
7220 NAME: mcast_miss_ttl
7221 IFDEF: MULTICAST_MISS_STREAM
7223 LOC: Config.mcast_miss.ttl
7226 This is the time-to-live value for packets multicasted
7227 when multicasting off cache miss URLs is enabled. By
7228 default this is set to 'site scope', i.e. 16.
7231 NAME: mcast_miss_port
7232 IFDEF: MULTICAST_MISS_STREAM
7234 LOC: Config.mcast_miss.port
7237 This is the port number to be used in conjunction with
7241 NAME: mcast_miss_encode_key
7242 IFDEF: MULTICAST_MISS_STREAM
7244 LOC: Config.mcast_miss.encode_key
7245 DEFAULT: XXXXXXXXXXXXXXXX
7247 The URLs that are sent in the multicast miss stream are
7248 encrypted. This is the encryption key.
7251 NAME: mcast_icp_query_timeout
7255 LOC: Config.Timeout.mcast_icp_query
7257 For multicast peers, Squid regularly sends out ICP "probes" to
7258 count how many other peers are listening on the given multicast
7259 address. This value specifies how long Squid should wait to
7260 count all the replies. The default is 2000 msec, or 2
7265 INTERNAL ICON OPTIONS
7266 -----------------------------------------------------------------------------
7269 NAME: icon_directory
7271 LOC: Config.icons.directory
7272 DEFAULT: @DEFAULT_ICON_DIR@
7274 Where the icons are stored. These are normally kept in
7278 NAME: global_internal_static
7280 LOC: Config.onoff.global_internal_static
7283 This directive controls is Squid should intercept all requests for
7284 /squid-internal-static/ no matter which host the URL is requesting
7285 (default on setting), or if nothing special should be done for
7286 such URLs (off setting). The purpose of this directive is to make
7287 icons etc work better in complex cache hierarchies where it may
7288 not always be possible for all corners in the cache mesh to reach
7289 the server generating a directory listing.
7292 NAME: short_icon_urls
7294 LOC: Config.icons.use_short_names
7297 If this is enabled Squid will use short URLs for icons.
7298 If disabled it will revert to the old behavior of including
7299 it's own name and port in the URL.
7301 If you run a complex cache hierarchy with a mix of Squid and
7302 other proxies you may need to disable this directive.
7307 -----------------------------------------------------------------------------
7310 NAME: error_directory
7312 LOC: Config.errorDirectory
7314 DEFAULT_DOC: Send error pages in the clients preferred language
7316 If you wish to create your own versions of the default
7317 error files to customize them to suit your company copy
7318 the error/template files to another directory and point
7321 WARNING: This option will disable multi-language support
7322 on error pages if used.
7324 The squid developers are interested in making squid available in
7325 a wide variety of languages. If you are making translations for a
7326 language that Squid does not currently provide please consider
7327 contributing your translation back to the project.
7328 http://wiki.squid-cache.org/Translations
7330 The squid developers working on translations are happy to supply drop-in
7331 translated error files in exchange for any new language contributions.
7334 NAME: error_default_language
7335 IFDEF: USE_ERR_LOCALES
7337 LOC: Config.errorDefaultLanguage
7339 DEFAULT_DOC: Generate English language pages.
7341 Set the default language which squid will send error pages in
7342 if no existing translation matches the clients language
7345 If unset (default) generic English will be used.
7347 The squid developers are interested in making squid available in
7348 a wide variety of languages. If you are interested in making
7349 translations for any language see the squid wiki for details.
7350 http://wiki.squid-cache.org/Translations
7353 NAME: error_log_languages
7354 IFDEF: USE_ERR_LOCALES
7356 LOC: Config.errorLogMissingLanguages
7359 Log to cache.log what languages users are attempting to
7360 auto-negotiate for translations.
7362 Successful negotiations are not logged. Only failures
7363 have meaning to indicate that Squid may need an upgrade
7364 of its error page translations.
7367 NAME: err_page_stylesheet
7369 LOC: Config.errorStylesheet
7370 DEFAULT: @DEFAULT_CONFIG_DIR@/errorpage.css
7372 CSS Stylesheet to pattern the display of Squid default error pages.
7374 For information on CSS see http://www.w3.org/Style/CSS/
7379 LOC: Config.errHtmlText
7382 HTML text to include in error messages. Make this a "mailto"
7383 URL to your admin address, or maybe just a link to your
7384 organizations Web page.
7386 To include this in your error messages, you must rewrite
7387 the error template files (found in the "errors" directory).
7388 Wherever you want the 'err_html_text' line to appear,
7389 insert a %L tag in the error template file.
7392 NAME: email_err_data
7395 LOC: Config.onoff.emailErrData
7398 If enabled, information about the occurred error will be
7399 included in the mailto links of the ERR pages (if %W is set)
7400 so that the email body contains the data.
7401 Syntax is <A HREF="mailto:%w%W">%w</A>
7406 LOC: Config.denyInfoList
7409 Usage: deny_info err_page_name acl
7410 or deny_info http://... acl
7411 or deny_info TCP_RESET acl
7413 This can be used to return a ERR_ page for requests which
7414 do not pass the 'http_access' rules. Squid remembers the last
7415 acl it evaluated in http_access, and if a 'deny_info' line exists
7416 for that ACL Squid returns a corresponding error page.
7418 The acl is typically the last acl on the http_access deny line which
7419 denied access. The exceptions to this rule are:
7420 - When Squid needs to request authentication credentials. It's then
7421 the first authentication related acl encountered
7422 - When none of the http_access lines matches. It's then the last
7423 acl processed on the last http_access line.
7424 - When the decision to deny access was made by an adaptation service,
7425 the acl name is the corresponding eCAP or ICAP service_name.
7427 NP: If providing your own custom error pages with error_directory
7428 you may also specify them by your custom file name:
7429 Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
7431 By defaut Squid will send "403 Forbidden". A different 4xx or 5xx
7432 may be specified by prefixing the file name with the code and a colon.
7433 e.g. 404:ERR_CUSTOM_ACCESS_DENIED
7435 Alternatively you can tell Squid to reset the TCP connection
7436 by specifying TCP_RESET.
7438 Or you can specify an error URL or URL pattern. The browsers will
7439 get redirected to the specified URL after formatting tags have
7440 been replaced. Redirect will be done with 302 or 307 according to
7441 HTTP/1.1 specs. A different 3xx code may be specified by prefixing
7442 the URL. e.g. 303:http://example.com/
7445 %a - username (if available. Password NOT included)
7448 %E - Error description
7450 %H - Request domain name
7451 %i - Client IP Address
7453 %o - Message result from external ACL helper
7454 %p - Request Port number
7455 %P - Request Protocol name
7456 %R - Request URL path
7457 %T - Timestamp in RFC 1123 format
7458 %U - Full canonical URL from client
7459 (HTTPS URLs terminate with *)
7460 %u - Full canonical URL from client
7461 %w - Admin email from squid.conf
7463 %% - Literal percent (%) code
7468 OPTIONS INFLUENCING REQUEST FORWARDING
7469 -----------------------------------------------------------------------------
7472 NAME: nonhierarchical_direct
7474 LOC: Config.onoff.nonhierarchical_direct
7477 By default, Squid will send any non-hierarchical requests
7478 (matching hierarchy_stoplist or not cacheable request type) direct
7481 When this is set to "off", Squid will prefer to send these
7482 requests to parents.
7484 Note that in most configurations, by turning this off you will only
7485 add latency to these request without any improvement in global hit
7488 This option only sets a preference. If the parent is unavailable a
7489 direct connection to the origin server may still be attempted. To
7490 completely prevent direct connections use never_direct.
7495 LOC: Config.onoff.prefer_direct
7498 Normally Squid tries to use parents for most requests. If you for some
7499 reason like it to first try going direct and only use a parent if
7500 going direct fails set this to on.
7502 By combining nonhierarchical_direct off and prefer_direct on you
7503 can set up Squid to use a parent as a backup path if going direct
7506 Note: If you want Squid to use parents for all requests see
7507 the never_direct directive. prefer_direct only modifies how Squid
7508 acts on cacheable requests.
7511 NAME: cache_miss_revalidate
7515 LOC: Config.onoff.cache_miss_revalidate
7517 RFC 7232 defines a conditional request mechanism to prevent
7518 response objects being unnecessarily transferred over the network.
7519 If that mechanism is used by the client and a cache MISS occurs
7520 it can prevent new cache entries being created.
7522 This option determines whether Squid on cache MISS will pass the
7523 client revalidation request to the server or tries to fetch new
7524 content for caching. It can be useful while the cache is mostly
7525 empty to more quickly have the cache populated by generating
7526 non-conditional GETs.
7528 When set to 'on' (default), Squid will pass all client If-* headers
7529 to the server. This permits server responses without a cacheable
7530 payload to be delivered and on MISS no new cache entry is created.
7532 When set to 'off' and if the request is cacheable, Squid will
7533 remove the clients If-Modified-Since and If-None-Match headers from
7534 the request sent to the server. This requests a 200 status response
7535 from the server to create a new cache entry with.
7540 LOC: Config.accessList.AlwaysDirect
7542 DEFAULT_DOC: Prevent any cache_peer being used for this request.
7544 Usage: always_direct allow|deny [!]aclname ...
7546 Here you can use ACL elements to specify requests which should
7547 ALWAYS be forwarded by Squid to the origin servers without using
7548 any peers. For example, to always directly forward requests for
7549 local servers ignoring any parents or siblings you may have use
7552 acl local-servers dstdomain my.domain.net
7553 always_direct allow local-servers
7555 To always forward FTP requests directly, use
7558 always_direct allow FTP
7560 NOTE: There is a similar, but opposite option named
7561 'never_direct'. You need to be aware that "always_direct deny
7562 foo" is NOT the same thing as "never_direct allow foo". You
7563 may need to use a deny rule to exclude a more-specific case of
7564 some other rule. Example:
7566 acl local-external dstdomain external.foo.net
7567 acl local-servers dstdomain .foo.net
7568 always_direct deny local-external
7569 always_direct allow local-servers
7571 NOTE: If your goal is to make the client forward the request
7572 directly to the origin server bypassing Squid then this needs
7573 to be done in the client configuration. Squid configuration
7574 can only tell Squid how Squid should fetch the object.
7576 NOTE: This directive is not related to caching. The replies
7577 is cached as usual even if you use always_direct. To not cache
7578 the replies see the 'cache' directive.
7580 This clause supports both fast and slow acl types.
7581 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7586 LOC: Config.accessList.NeverDirect
7588 DEFAULT_DOC: Allow DNS results to be used for this request.
7590 Usage: never_direct allow|deny [!]aclname ...
7592 never_direct is the opposite of always_direct. Please read
7593 the description for always_direct if you have not already.
7595 With 'never_direct' you can use ACL elements to specify
7596 requests which should NEVER be forwarded directly to origin
7597 servers. For example, to force the use of a proxy for all
7598 requests, except those in your local domain use something like:
7600 acl local-servers dstdomain .foo.net
7601 never_direct deny local-servers
7602 never_direct allow all
7604 or if Squid is inside a firewall and there are local intranet
7605 servers inside the firewall use something like:
7607 acl local-intranet dstdomain .foo.net
7608 acl local-external dstdomain external.foo.net
7609 always_direct deny local-external
7610 always_direct allow local-intranet
7611 never_direct allow all
7613 This clause supports both fast and slow acl types.
7614 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
7618 ADVANCED NETWORKING OPTIONS
7619 -----------------------------------------------------------------------------
7622 NAME: incoming_udp_average incoming_icp_average
7625 LOC: Config.comm_incoming.udp.average
7627 Heavy voodoo here. I can't even believe you are reading this.
7628 Are you crazy? Don't even think about adjusting these unless
7629 you understand the algorithms in comm_select.c first!
7632 NAME: incoming_tcp_average incoming_http_average
7635 LOC: Config.comm_incoming.tcp.average
7637 Heavy voodoo here. I can't even believe you are reading this.
7638 Are you crazy? Don't even think about adjusting these unless
7639 you understand the algorithms in comm_select.c first!
7642 NAME: incoming_dns_average
7645 LOC: Config.comm_incoming.dns.average
7647 Heavy voodoo here. I can't even believe you are reading this.
7648 Are you crazy? Don't even think about adjusting these unless
7649 you understand the algorithms in comm_select.c first!
7652 NAME: min_udp_poll_cnt min_icp_poll_cnt
7655 LOC: Config.comm_incoming.udp.min_poll
7657 Heavy voodoo here. I can't even believe you are reading this.
7658 Are you crazy? Don't even think about adjusting these unless
7659 you understand the algorithms in comm_select.c first!
7662 NAME: min_dns_poll_cnt
7665 LOC: Config.comm_incoming.dns.min_poll
7667 Heavy voodoo here. I can't even believe you are reading this.
7668 Are you crazy? Don't even think about adjusting these unless
7669 you understand the algorithms in comm_select.c first!
7672 NAME: min_tcp_poll_cnt min_http_poll_cnt
7675 LOC: Config.comm_incoming.tcp.min_poll
7677 Heavy voodoo here. I can't even believe you are reading this.
7678 Are you crazy? Don't even think about adjusting these unless
7679 you understand the algorithms in comm_select.c first!
7685 LOC: Config.accept_filter
7689 The name of an accept(2) filter to install on Squid's
7690 listen socket(s). This feature is perhaps specific to
7691 FreeBSD and requires support in the kernel.
7693 The 'httpready' filter delays delivering new connections
7694 to Squid until a full HTTP request has been received.
7695 See the accf_http(9) man page for details.
7697 The 'dataready' filter delays delivering new connections
7698 to Squid until there is some data to process.
7699 See the accf_dataready(9) man page for details.
7703 The 'data' filter delays delivering of new connections
7704 to Squid until there is some data to process by TCP_ACCEPT_DEFER.
7705 You may optionally specify a number of seconds to wait by
7706 'data=N' where N is the number of seconds. Defaults to 30
7707 if not specified. See the tcp(7) man page for details.
7710 accept_filter httpready
7715 NAME: client_ip_max_connections
7717 LOC: Config.client_ip_max_connections
7719 DEFAULT_DOC: No limit.
7721 Set an absolute limit on the number of connections a single
7722 client IP can use. Any more than this and Squid will begin to drop
7723 new connections from the client until it closes some links.
7725 Note that this is a global limit. It affects all HTTP, HTCP, Gopher and FTP
7726 connections from the client. For finer control use the ACL access controls.
7728 Requires client_db to be enabled (the default).
7730 WARNING: This may noticably slow down traffic received via external proxies
7731 or NAT devices and cause them to rebound error messages back to their clients.
7734 NAME: tcp_recv_bufsize
7738 DEFAULT_DOC: Use operating system TCP defaults.
7739 LOC: Config.tcpRcvBufsz
7741 Size of receive buffer to set for TCP sockets. Probably just
7742 as easy to change your kernel's default.
7743 Omit from squid.conf to use the default buffer size.
7748 -----------------------------------------------------------------------------
7755 LOC: Adaptation::Icap::TheConfig.onoff
7758 If you want to enable the ICAP module support, set this to on.
7761 NAME: icap_connect_timeout
7764 LOC: Adaptation::Icap::TheConfig.connect_timeout_raw
7767 This parameter specifies how long to wait for the TCP connect to
7768 the requested ICAP server to complete before giving up and either
7769 terminating the HTTP transaction or bypassing the failure.
7771 The default for optional services is peer_connect_timeout.
7772 The default for essential services is connect_timeout.
7773 If this option is explicitly set, its value applies to all services.
7776 NAME: icap_io_timeout
7780 DEFAULT_DOC: Use read_timeout.
7781 LOC: Adaptation::Icap::TheConfig.io_timeout_raw
7784 This parameter specifies how long to wait for an I/O activity on
7785 an established, active ICAP connection before giving up and
7786 either terminating the HTTP transaction or bypassing the
7790 NAME: icap_service_failure_limit
7791 COMMENT: limit [in memory-depth time-units]
7792 TYPE: icap_service_failure_limit
7794 LOC: Adaptation::Icap::TheConfig
7797 The limit specifies the number of failures that Squid tolerates
7798 when establishing a new TCP connection with an ICAP service. If
7799 the number of failures exceeds the limit, the ICAP service is
7800 not used for new ICAP requests until it is time to refresh its
7803 A negative value disables the limit. Without the limit, an ICAP
7804 service will not be considered down due to connectivity failures
7805 between ICAP OPTIONS requests.
7807 Squid forgets ICAP service failures older than the specified
7808 value of memory-depth. The memory fading algorithm
7809 is approximate because Squid does not remember individual
7810 errors but groups them instead, splitting the option
7811 value into ten time slots of equal length.
7813 When memory-depth is 0 and by default this option has no
7814 effect on service failure expiration.
7816 Squid always forgets failures when updating service settings
7817 using an ICAP OPTIONS transaction, regardless of this option
7821 # suspend service usage after 10 failures in 5 seconds:
7822 icap_service_failure_limit 10 in 5 seconds
7825 NAME: icap_service_revival_delay
7828 LOC: Adaptation::Icap::TheConfig.service_revival_delay
7831 The delay specifies the number of seconds to wait after an ICAP
7832 OPTIONS request failure before requesting the options again. The
7833 failed ICAP service is considered "down" until fresh OPTIONS are
7836 The actual delay cannot be smaller than the hardcoded minimum
7837 delay of 30 seconds.
7840 NAME: icap_preview_enable
7844 LOC: Adaptation::Icap::TheConfig.preview_enable
7847 The ICAP Preview feature allows the ICAP server to handle the
7848 HTTP message by looking only at the beginning of the message body
7849 or even without receiving the body at all. In some environments,
7850 previews greatly speedup ICAP processing.
7852 During an ICAP OPTIONS transaction, the server may tell Squid what
7853 HTTP messages should be previewed and how big the preview should be.
7854 Squid will not use Preview if the server did not request one.
7856 To disable ICAP Preview for all ICAP services, regardless of
7857 individual ICAP server OPTIONS responses, set this option to "off".
7859 icap_preview_enable off
7862 NAME: icap_preview_size
7865 LOC: Adaptation::Icap::TheConfig.preview_size
7867 DEFAULT_DOC: No preview sent.
7869 The default size of preview data to be sent to the ICAP server.
7870 This value might be overwritten on a per server basis by OPTIONS requests.
7873 NAME: icap_206_enable
7877 LOC: Adaptation::Icap::TheConfig.allow206_enable
7880 206 (Partial Content) responses is an ICAP extension that allows the
7881 ICAP agents to optionally combine adapted and original HTTP message
7882 content. The decision to combine is postponed until the end of the
7883 ICAP response. Squid supports Partial Content extension by default.
7885 Activation of the Partial Content extension is negotiated with each
7886 ICAP service during OPTIONS exchange. Most ICAP servers should handle
7887 negotation correctly even if they do not support the extension, but
7888 some might fail. To disable Partial Content support for all ICAP
7889 services and to avoid any negotiation, set this option to "off".
7895 NAME: icap_default_options_ttl
7898 LOC: Adaptation::Icap::TheConfig.default_options_ttl
7901 The default TTL value for ICAP OPTIONS responses that don't have
7902 an Options-TTL header.
7905 NAME: icap_persistent_connections
7909 LOC: Adaptation::Icap::TheConfig.reuse_connections
7912 Whether or not Squid should use persistent connections to
7916 NAME: adaptation_send_client_ip icap_send_client_ip
7918 IFDEF: USE_ADAPTATION
7920 LOC: Adaptation::Config::send_client_ip
7923 If enabled, Squid shares HTTP client IP information with adaptation
7924 services. For ICAP, Squid adds the X-Client-IP header to ICAP requests.
7925 For eCAP, Squid sets the libecap::metaClientIp transaction option.
7927 See also: adaptation_uses_indirect_client
7930 NAME: adaptation_send_username icap_send_client_username
7932 IFDEF: USE_ADAPTATION
7934 LOC: Adaptation::Config::send_username
7937 This sends authenticated HTTP client username (if available) to
7938 the adaptation service.
7940 For ICAP, the username value is encoded based on the
7941 icap_client_username_encode option and is sent using the header
7942 specified by the icap_client_username_header option.
7945 NAME: icap_client_username_header
7948 LOC: Adaptation::Icap::TheConfig.client_username_header
7949 DEFAULT: X-Client-Username
7951 ICAP request header name to use for adaptation_send_username.
7954 NAME: icap_client_username_encode
7958 LOC: Adaptation::Icap::TheConfig.client_username_encode
7961 Whether to base64 encode the authenticated client username.
7965 TYPE: icap_service_type
7967 LOC: Adaptation::Icap::TheConfig
7970 Defines a single ICAP service using the following format:
7972 icap_service id vectoring_point uri [option ...]
7975 an opaque identifier or name which is used to direct traffic to
7976 this specific service. Must be unique among all adaptation
7977 services in squid.conf.
7979 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
7980 This specifies at which point of transaction processing the
7981 ICAP service should be activated. *_postcache vectoring points
7982 are not yet supported.
7984 uri: icap://servername:port/servicepath
7985 ICAP server and service location.
7987 ICAP does not allow a single service to handle both REQMOD and RESPMOD
7988 transactions. Squid does not enforce that requirement. You can specify
7989 services with the same service_url and different vectoring_points. You
7990 can even specify multiple identical services as long as their
7991 service_names differ.
7993 To activate a service, use the adaptation_access directive. To group
7994 services, use adaptation_service_chain and adaptation_service_set.
7996 Service options are separated by white space. ICAP services support
7997 the following name=value options:
8000 If set to 'on' or '1', the ICAP service is treated as
8001 optional. If the service cannot be reached or malfunctions,
8002 Squid will try to ignore any errors and process the message as
8003 if the service was not enabled. No all ICAP errors can be
8004 bypassed. If set to 0, the ICAP service is treated as
8005 essential and all ICAP errors will result in an error page
8006 returned to the HTTP client.
8008 Bypass is off by default: services are treated as essential.
8011 If set to 'on' or '1', the ICAP service is allowed to
8012 dynamically change the current message adaptation plan by
8013 returning a chain of services to be used next. The services
8014 are specified using the X-Next-Services ICAP response header
8015 value, formatted as a comma-separated list of service names.
8016 Each named service should be configured in squid.conf. Other
8017 services are ignored. An empty X-Next-Services value results
8018 in an empty plan which ends the current adaptation.
8020 Dynamic adaptation plan may cross or cover multiple supported
8021 vectoring points in their natural processing order.
8023 Routing is not allowed by default: the ICAP X-Next-Services
8024 response header is ignored.
8027 Only has effect on split-stack systems. The default on those systems
8028 is to use IPv4-only connections. When set to 'on' this option will
8029 make Squid use IPv6-only connections to contact this ICAP service.
8031 on-overload=block|bypass|wait|force
8032 If the service Max-Connections limit has been reached, do
8033 one of the following for each new ICAP transaction:
8034 * block: send an HTTP error response to the client
8035 * bypass: ignore the "over-connected" ICAP service
8036 * wait: wait (in a FIFO queue) for an ICAP connection slot
8037 * force: proceed, ignoring the Max-Connections limit
8039 In SMP mode with N workers, each worker assumes the service
8040 connection limit is Max-Connections/N, even though not all
8041 workers may use a given service.
8043 The default value is "bypass" if service is bypassable,
8044 otherwise it is set to "wait".
8048 Use the given number as the Max-Connections limit, regardless
8049 of the Max-Connections value given by the service, if any.
8051 Older icap_service format without optional named parameters is
8052 deprecated but supported for backward compatibility.
8055 icap_service svcBlocker reqmod_precache icap://icap1.mydomain.net:1344/reqmod bypass=0
8056 icap_service svcLogger reqmod_precache icap://icap2.mydomain.net:1344/respmod routing=on
8060 TYPE: icap_class_type
8065 This deprecated option was documented to define an ICAP service
8066 chain, even though it actually defined a set of similar, redundant
8067 services, and the chains were not supported.
8069 To define a set of redundant services, please use the
8070 adaptation_service_set directive. For service chains, use
8071 adaptation_service_chain.
8075 TYPE: icap_access_type
8080 This option is deprecated. Please use adaptation_access, which
8081 has the same ICAP functionality, but comes with better
8082 documentation, and eCAP support.
8087 -----------------------------------------------------------------------------
8094 LOC: Adaptation::Ecap::TheConfig.onoff
8097 Controls whether eCAP support is enabled.
8101 TYPE: ecap_service_type
8103 LOC: Adaptation::Ecap::TheConfig
8106 Defines a single eCAP service
8108 ecap_service id vectoring_point uri [option ...]
8111 an opaque identifier or name which is used to direct traffic to
8112 this specific service. Must be unique among all adaptation
8113 services in squid.conf.
8115 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
8116 This specifies at which point of transaction processing the
8117 eCAP service should be activated. *_postcache vectoring points
8118 are not yet supported.
8120 uri: ecap://vendor/service_name?custom&cgi=style¶meters=optional
8121 Squid uses the eCAP service URI to match this configuration
8122 line with one of the dynamically loaded services. Each loaded
8123 eCAP service must have a unique URI. Obtain the right URI from
8124 the service provider.
8126 To activate a service, use the adaptation_access directive. To group
8127 services, use adaptation_service_chain and adaptation_service_set.
8129 Service options are separated by white space. eCAP services support
8130 the following name=value options:
8133 If set to 'on' or '1', the eCAP service is treated as optional.
8134 If the service cannot be reached or malfunctions, Squid will try
8135 to ignore any errors and process the message as if the service
8136 was not enabled. No all eCAP errors can be bypassed.
8137 If set to 'off' or '0', the eCAP service is treated as essential
8138 and all eCAP errors will result in an error page returned to the
8141 Bypass is off by default: services are treated as essential.
8144 If set to 'on' or '1', the eCAP service is allowed to
8145 dynamically change the current message adaptation plan by
8146 returning a chain of services to be used next.
8148 Dynamic adaptation plan may cross or cover multiple supported
8149 vectoring points in their natural processing order.
8151 Routing is not allowed by default.
8153 Older ecap_service format without optional named parameters is
8154 deprecated but supported for backward compatibility.
8158 ecap_service s1 reqmod_precache ecap://filters.R.us/leakDetector?on_error=block bypass=off
8159 ecap_service s2 respmod_precache ecap://filters.R.us/virusFilter config=/etc/vf.cfg bypass=on
8162 NAME: loadable_modules
8164 IFDEF: USE_LOADABLE_MODULES
8165 LOC: Config.loadable_module_names
8168 Instructs Squid to load the specified dynamic module(s) or activate
8169 preloaded module(s).
8171 loadable_modules @DEFAULT_PREFIX@/lib/MinimalAdapter.so
8175 MESSAGE ADAPTATION OPTIONS
8176 -----------------------------------------------------------------------------
8179 NAME: adaptation_service_set
8180 TYPE: adaptation_service_set_type
8181 IFDEF: USE_ADAPTATION
8186 Configures an ordered set of similar, redundant services. This is
8187 useful when hot standby or backup adaptation servers are available.
8189 adaptation_service_set set_name service_name1 service_name2 ...
8191 The named services are used in the set declaration order. The first
8192 applicable adaptation service from the set is used first. The next
8193 applicable service is tried if and only if the transaction with the
8194 previous service fails and the message waiting to be adapted is still
8197 When adaptation starts, broken services are ignored as if they were
8198 not a part of the set. A broken service is a down optional service.
8200 The services in a set must be attached to the same vectoring point
8201 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
8203 If all services in a set are optional then adaptation failures are
8204 bypassable. If all services in the set are essential, then a
8205 transaction failure with one service may still be retried using
8206 another service from the set, but when all services fail, the master
8207 transaction fails as well.
8209 A set may contain a mix of optional and essential services, but that
8210 is likely to lead to surprising results because broken services become
8211 ignored (see above), making previously bypassable failures fatal.
8212 Technically, it is the bypassability of the last failed service that
8215 See also: adaptation_access adaptation_service_chain
8218 adaptation_service_set svcBlocker urlFilterPrimary urlFilterBackup
8219 adaptation service_set svcLogger loggerLocal loggerRemote
8222 NAME: adaptation_service_chain
8223 TYPE: adaptation_service_chain_type
8224 IFDEF: USE_ADAPTATION
8229 Configures a list of complementary services that will be applied
8230 one-by-one, forming an adaptation chain or pipeline. This is useful
8231 when Squid must perform different adaptations on the same message.
8233 adaptation_service_chain chain_name service_name1 svc_name2 ...
8235 The named services are used in the chain declaration order. The first
8236 applicable adaptation service from the chain is used first. The next
8237 applicable service is applied to the successful adaptation results of
8238 the previous service in the chain.
8240 When adaptation starts, broken services are ignored as if they were
8241 not a part of the chain. A broken service is a down optional service.
8243 Request satisfaction terminates the adaptation chain because Squid
8244 does not currently allow declaration of RESPMOD services at the
8245 "reqmod_precache" vectoring point (see icap_service or ecap_service).
8247 The services in a chain must be attached to the same vectoring point
8248 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
8250 A chain may contain a mix of optional and essential services. If an
8251 essential adaptation fails (or the failure cannot be bypassed for
8252 other reasons), the master transaction fails. Otherwise, the failure
8253 is bypassed as if the failed adaptation service was not in the chain.
8255 See also: adaptation_access adaptation_service_set
8258 adaptation_service_chain svcRequest requestLogger urlFilter leakDetector
8261 NAME: adaptation_access
8262 TYPE: adaptation_access_type
8263 IFDEF: USE_ADAPTATION
8266 DEFAULT_DOC: Allow, unless rules exist in squid.conf.
8268 Sends an HTTP transaction to an ICAP or eCAP adaptation service.
8270 adaptation_access service_name allow|deny [!]aclname...
8271 adaptation_access set_name allow|deny [!]aclname...
8273 At each supported vectoring point, the adaptation_access
8274 statements are processed in the order they appear in this
8275 configuration file. Statements pointing to the following services
8276 are ignored (i.e., skipped without checking their ACL):
8278 - services serving different vectoring points
8279 - "broken-but-bypassable" services
8280 - "up" services configured to ignore such transactions
8281 (e.g., based on the ICAP Transfer-Ignore header).
8283 When a set_name is used, all services in the set are checked
8284 using the same rules, to find the first applicable one. See
8285 adaptation_service_set for details.
8287 If an access list is checked and there is a match, the
8288 processing stops: For an "allow" rule, the corresponding
8289 adaptation service is used for the transaction. For a "deny"
8290 rule, no adaptation service is activated.
8292 It is currently not possible to apply more than one adaptation
8293 service at the same vectoring point to the same HTTP transaction.
8295 See also: icap_service and ecap_service
8298 adaptation_access service_1 allow all
8301 NAME: adaptation_service_iteration_limit
8303 IFDEF: USE_ADAPTATION
8304 LOC: Adaptation::Config::service_iteration_limit
8307 Limits the number of iterations allowed when applying adaptation
8308 services to a message. If your longest adaptation set or chain
8309 may have more than 16 services, increase the limit beyond its
8310 default value of 16. If detecting infinite iteration loops sooner
8311 is critical, make the iteration limit match the actual number
8312 of services in your longest adaptation set or chain.
8314 Infinite adaptation loops are most likely with routing services.
8316 See also: icap_service routing=1
8319 NAME: adaptation_masterx_shared_names
8321 IFDEF: USE_ADAPTATION
8322 LOC: Adaptation::Config::masterx_shared_name
8325 For each master transaction (i.e., the HTTP request and response
8326 sequence, including all related ICAP and eCAP exchanges), Squid
8327 maintains a table of metadata. The table entries are (name, value)
8328 pairs shared among eCAP and ICAP exchanges. The table is destroyed
8329 with the master transaction.
8331 This option specifies the table entry names that Squid must accept
8332 from and forward to the adaptation transactions.
8334 An ICAP REQMOD or RESPMOD transaction may set an entry in the
8335 shared table by returning an ICAP header field with a name
8336 specified in adaptation_masterx_shared_names.
8338 An eCAP REQMOD or RESPMOD transaction may set an entry in the
8339 shared table by implementing the libecap::visitEachOption() API
8340 to provide an option with a name specified in
8341 adaptation_masterx_shared_names.
8343 Squid will store and forward the set entry to subsequent adaptation
8344 transactions within the same master transaction scope.
8346 Only one shared entry name is supported at this time.
8349 # share authentication information among ICAP services
8350 adaptation_masterx_shared_names X-Subscriber-ID
8353 NAME: adaptation_meta
8355 IFDEF: USE_ADAPTATION
8356 LOC: Adaptation::Config::metaHeaders
8359 This option allows Squid administrator to add custom ICAP request
8360 headers or eCAP options to Squid ICAP requests or eCAP transactions.
8361 Use it to pass custom authentication tokens and other
8362 transaction-state related meta information to an ICAP/eCAP service.
8364 The addition of a meta header is ACL-driven:
8365 adaptation_meta name value [!]aclname ...
8367 Processing for a given header name stops after the first ACL list match.
8368 Thus, it is impossible to add two headers with the same name. If no ACL
8369 lists match for a given header name, no such header is added. For
8372 # do not debug transactions except for those that need debugging
8373 adaptation_meta X-Debug 1 needs_debugging
8375 # log all transactions except for those that must remain secret
8376 adaptation_meta X-Log 1 !keep_secret
8378 # mark transactions from users in the "G 1" group
8379 adaptation_meta X-Authenticated-Groups "G 1" authed_as_G1
8381 The "value" parameter may be a regular squid.conf token or a "double
8382 quoted string". Within the quoted string, use backslash (\) to escape
8383 any character, which is currently only useful for escaping backslashes
8384 and double quotes. For example,
8385 "this string has one backslash (\\) and two \"quotes\""
8387 Used adaptation_meta header values may be logged via %note
8388 logformat code. If multiple adaptation_meta headers with the same name
8389 are used during master transaction lifetime, the header values are
8390 logged in the order they were used and duplicate values are ignored
8391 (only the first repeated value will be logged).
8397 LOC: Adaptation::Icap::TheConfig.repeat
8398 DEFAULT_IF_NONE: deny all
8400 This ACL determines which retriable ICAP transactions are
8401 retried. Transactions that received a complete ICAP response
8402 and did not have to consume or produce HTTP bodies to receive
8403 that response are usually retriable.
8405 icap_retry allow|deny [!]aclname ...
8407 Squid automatically retries some ICAP I/O timeouts and errors
8408 due to persistent connection race conditions.
8410 See also: icap_retry_limit
8413 NAME: icap_retry_limit
8416 LOC: Adaptation::Icap::TheConfig.repeat_limit
8418 DEFAULT_DOC: No retries are allowed.
8420 Limits the number of retries allowed.
8422 Communication errors due to persistent connection race
8423 conditions are unavoidable, automatically retried, and do not
8424 count against this limit.
8426 See also: icap_retry
8432 -----------------------------------------------------------------------------
8435 NAME: check_hostnames
8438 LOC: Config.onoff.check_hostnames
8440 For security and stability reasons Squid can check
8441 hostnames for Internet standard RFC compliance. If you want
8442 Squid to perform these checks turn this directive on.
8445 NAME: allow_underscore
8448 LOC: Config.onoff.allow_underscore
8450 Underscore characters is not strictly allowed in Internet hostnames
8451 but nevertheless used by many sites. Set this to off if you want
8452 Squid to be strict about the standard.
8453 This check is performed only when check_hostnames is set to on.
8456 NAME: dns_retransmit_interval
8459 LOC: Config.Timeout.idns_retransmit
8461 Initial retransmit interval for DNS queries. The interval is
8462 doubled each time all configured DNS servers have been tried.
8468 LOC: Config.Timeout.idns_query
8470 DNS Query timeout. If no response is received to a DNS query
8471 within this time all DNS servers for the queried domain
8472 are assumed to be unavailable.
8475 NAME: dns_packet_max
8477 DEFAULT_DOC: EDNS disabled
8479 LOC: Config.dns.packet_max
8481 Maximum number of bytes packet size to advertise via EDNS.
8482 Set to "none" to disable EDNS large packet support.
8484 For legacy reasons DNS UDP replies will default to 512 bytes which
8485 is too small for many responses. EDNS provides a means for Squid to
8486 negotiate receiving larger responses back immediately without having
8487 to failover with repeat requests. Responses larger than this limit
8488 will retain the old behaviour of failover to TCP DNS.
8490 Squid has no real fixed limit internally, but allowing packet sizes
8491 over 1500 bytes requires network jumbogram support and is usually not
8494 WARNING: The RFC also indicates that some older resolvers will reply
8495 with failure of the whole request if the extension is added. Some
8496 resolvers have already been identified which will reply with mangled
8497 EDNS response on occasion. Usually in response to many-KB jumbogram
8498 sizes being advertised by Squid.
8499 Squid will currently treat these both as an unable-to-resolve domain
8500 even if it would be resolvable without EDNS.
8507 DEFAULT_DOC: Search for single-label domain names is disabled.
8508 LOC: Config.onoff.res_defnames
8510 Normally the RES_DEFNAMES resolver option is disabled
8511 (see res_init(3)). This prevents caches in a hierarchy
8512 from interpreting single-component hostnames locally. To allow
8513 Squid to handle single-component names, enable this option.
8516 NAME: dns_multicast_local
8520 DEFAULT_DOC: Search for .local and .arpa names is disabled.
8521 LOC: Config.onoff.dns_mdns
8523 When set to on, Squid sends multicast DNS lookups on the local
8524 network for domains ending in .local and .arpa.
8525 This enables local servers and devices to be contacted in an
8526 ad-hoc or zero-configuration network environment.
8529 NAME: dns_nameservers
8532 DEFAULT_DOC: Use operating system definitions
8533 LOC: Config.dns_nameservers
8535 Use this if you want to specify a list of DNS name servers
8536 (IP addresses) to use instead of those given in your
8537 /etc/resolv.conf file.
8539 On Windows platforms, if no value is specified here or in
8540 the /etc/resolv.conf file, the list of DNS name servers are
8541 taken from the Windows registry, both static and dynamic DHCP
8542 configurations are supported.
8544 Example: dns_nameservers 10.0.0.1 192.172.0.4
8549 DEFAULT: @DEFAULT_HOSTS@
8550 LOC: Config.etcHostsPath
8552 Location of the host-local IP name-address associations
8553 database. Most Operating Systems have such a file on different
8555 - Un*X & Linux: /etc/hosts
8556 - Windows NT/2000: %SystemRoot%\system32\drivers\etc\hosts
8557 (%SystemRoot% value install default is c:\winnt)
8558 - Windows XP/2003: %SystemRoot%\system32\drivers\etc\hosts
8559 (%SystemRoot% value install default is c:\windows)
8560 - Windows 9x/Me: %windir%\hosts
8561 (%windir% value is usually c:\windows)
8562 - Cygwin: /etc/hosts
8564 The file contains newline-separated definitions, in the
8565 form ip_address_in_dotted_form name [name ...] names are
8566 whitespace-separated. Lines beginning with an hash (#)
8567 character are comments.
8569 The file is checked at startup and upon configuration.
8570 If set to 'none', it won't be checked.
8571 If append_domain is used, that domain will be added to
8572 domain-local (i.e. not containing any dot character) host
8578 LOC: Config.appendDomain
8580 DEFAULT_DOC: Use operating system definitions
8582 Appends local domain name to hostnames without any dots in
8583 them. append_domain must begin with a period.
8585 Be warned there are now Internet names with no dots in
8586 them using only top-domain names, so setting this may
8587 cause some Internet sites to become unavailable.
8590 append_domain .yourdomain.com
8593 NAME: ignore_unknown_nameservers
8595 LOC: Config.onoff.ignore_unknown_nameservers
8598 By default Squid checks that DNS responses are received
8599 from the same IP addresses they are sent to. If they
8600 don't match, Squid ignores the response and writes a warning
8601 message to cache.log. You can allow responses from unknown
8602 nameservers by setting this option to 'off'.
8608 LOC: Config.dns.v4_first
8610 With the IPv6 Internet being as fast or faster than IPv4 Internet
8611 for most networks Squid prefers to contact websites over IPv6.
8613 This option reverses the order of preference to make Squid contact
8614 dual-stack websites over IPv4 first. Squid will still perform both
8615 IPv6 and IPv4 DNS lookups before connecting.
8618 This option will restrict the situations under which IPv6
8619 connectivity is used (and tested). Hiding network problems
8620 which would otherwise be detected and warned about.
8624 COMMENT: (number of entries)
8627 LOC: Config.ipcache.size
8629 Maximum number of DNS IP cache entries.
8636 LOC: Config.ipcache.low
8643 LOC: Config.ipcache.high
8645 The size, low-, and high-water marks for the IP cache.
8648 NAME: fqdncache_size
8649 COMMENT: (number of entries)
8652 LOC: Config.fqdncache.size
8654 Maximum number of FQDN cache entries.
8659 -----------------------------------------------------------------------------
8662 NAME: configuration_includes_quoted_values
8664 TYPE: configuration_includes_quoted_values
8666 LOC: ConfigParser::RecognizeQuotedValues
8668 If set, Squid will recognize each "quoted string" after a configuration
8669 directive as a single parameter. The quotes are stripped before the
8670 parameter value is interpreted or used.
8671 See "Values with spaces, quotes, and other special characters"
8672 section for more details.
8679 LOC: Config.onoff.mem_pools
8681 If set, Squid will keep pools of allocated (but unused) memory
8682 available for future use. If memory is a premium on your
8683 system and you believe your malloc library outperforms Squid
8684 routines, disable this.
8687 NAME: memory_pools_limit
8691 LOC: Config.MemPools.limit
8693 Used only with memory_pools on:
8694 memory_pools_limit 50 MB
8696 If set to a non-zero value, Squid will keep at most the specified
8697 limit of allocated (but unused) memory in memory pools. All free()
8698 requests that exceed this limit will be handled by your malloc
8699 library. Squid does not pre-allocate any memory, just safe-keeps
8700 objects that otherwise would be free()d. Thus, it is safe to set
8701 memory_pools_limit to a reasonably high value even if your
8702 configuration will use less memory.
8704 If set to none, Squid will keep all memory it can. That is, there
8705 will be no limit on the total amount of memory used for safe-keeping.
8707 To disable memory allocation optimization, do not set
8708 memory_pools_limit to 0 or none. Set memory_pools to "off" instead.
8710 An overhead for maintaining memory pools is not taken into account
8711 when the limit is checked. This overhead is close to four bytes per
8712 object kept. However, pools may actually _save_ memory because of
8713 reduced memory thrashing in your malloc library.
8717 COMMENT: on|off|transparent|truncate|delete
8720 LOC: opt_forwarded_for
8722 If set to "on", Squid will append your client's IP address
8723 in the HTTP requests it forwards. By default it looks like:
8725 X-Forwarded-For: 192.1.2.3
8727 If set to "off", it will appear as
8729 X-Forwarded-For: unknown
8731 If set to "transparent", Squid will not alter the
8732 X-Forwarded-For header in any way.
8734 If set to "delete", Squid will delete the entire
8735 X-Forwarded-For header.
8737 If set to "truncate", Squid will remove all existing
8738 X-Forwarded-For entries, and place the client IP as the sole entry.
8741 NAME: cachemgr_passwd
8742 TYPE: cachemgrpasswd
8744 DEFAULT_DOC: No password. Actions which require password are denied.
8745 LOC: Config.passwd_list
8747 Specify passwords for cachemgr operations.
8749 Usage: cachemgr_passwd password action action ...
8751 Some valid actions are (see cache manager menu for a full list):
8791 * Indicates actions which will not be performed without a
8792 valid password, others can be performed if not listed here.
8794 To disable an action, set the password to "disable".
8795 To allow performing an action without a password, set the
8798 Use the keyword "all" to set the same password for all actions.
8801 cachemgr_passwd secret shutdown
8802 cachemgr_passwd lesssssssecret info stats/objects
8803 cachemgr_passwd disable all
8810 LOC: Config.onoff.client_db
8812 If you want to disable collecting per-client statistics,
8813 turn off client_db here.
8816 NAME: refresh_all_ims
8820 LOC: Config.onoff.refresh_all_ims
8822 When you enable this option, squid will always check
8823 the origin server for an update when a client sends an
8824 If-Modified-Since request. Many browsers use IMS
8825 requests when the user requests a reload, and this
8826 ensures those clients receive the latest version.
8828 By default (off), squid may return a Not Modified response
8829 based on the age of the cached version.
8832 NAME: reload_into_ims
8833 IFDEF: USE_HTTP_VIOLATIONS
8837 LOC: Config.onoff.reload_into_ims
8839 When you enable this option, client no-cache or ``reload''
8840 requests will be changed to If-Modified-Since requests.
8841 Doing this VIOLATES the HTTP standard. Enabling this
8842 feature could make you liable for problems which it
8845 see also refresh_pattern for a more selective approach.
8848 NAME: connect_retries
8850 LOC: Config.connect_retries
8852 DEFAULT_DOC: Do not retry failed connections.
8854 This sets the maximum number of connection attempts made for each
8855 TCP connection. The connect_retries attempts must all still
8856 complete within the connection timeout period.
8858 The default is not to re-try if the first connection attempt fails.
8859 The (not recommended) maximum is 10 tries.
8861 A warning message will be generated if it is set to a too-high
8862 value and the configured value will be over-ridden.
8864 Note: These re-tries are in addition to forward_max_tries
8865 which limit how many different addresses may be tried to find
8869 NAME: retry_on_error
8871 LOC: Config.retry.onerror
8874 If set to ON Squid will automatically retry requests when
8875 receiving an error response with status 403 (Forbidden),
8876 500 (Internal Error), 501 or 503 (Service not available).
8877 Status 502 and 504 (Gateway errors) are always retried.
8879 This is mainly useful if you are in a complex cache hierarchy to
8880 work around access control errors.
8882 NOTE: This retry will attempt to find another working destination.
8883 Which is different from the server which just failed.
8886 NAME: as_whois_server
8888 LOC: Config.as_whois_server
8889 DEFAULT: whois.ra.net
8891 WHOIS server to query for AS numbers. NOTE: AS numbers are
8892 queried only when Squid starts up, not for every request.
8897 LOC: Config.onoff.offline
8900 Enable this option and Squid will never try to validate cached
8904 NAME: uri_whitespace
8905 TYPE: uri_whitespace
8906 LOC: Config.uri_whitespace
8909 What to do with requests that have whitespace characters in the
8912 strip: The whitespace characters are stripped out of the URL.
8913 This is the behavior recommended by RFC2396 and RFC3986
8914 for tolerant handling of generic URI.
8915 NOTE: This is one difference between generic URI and HTTP URLs.
8917 deny: The request is denied. The user receives an "Invalid
8919 This is the behaviour recommended by RFC2616 for safe
8920 handling of HTTP request URL.
8922 allow: The request is allowed and the URI is not changed. The
8923 whitespace characters remain in the URI. Note the
8924 whitespace is passed to redirector processes if they
8926 Note this may be considered a violation of RFC2616
8927 request parsing where whitespace is prohibited in the
8930 encode: The request is allowed and the whitespace characters are
8931 encoded according to RFC1738.
8933 chop: The request is allowed and the URI is chopped at the
8937 NOTE the current Squid implementation of encode and chop violates
8938 RFC2616 by not using a 301 redirect after altering the URL.
8943 LOC: Config.chroot_dir
8946 Specifies a directory where Squid should do a chroot() while
8947 initializing. This also causes Squid to fully drop root
8948 privileges after initializing. This means, for example, if you
8949 use a HTTP port less than 1024 and try to reconfigure, you may
8950 get an error saying that Squid can not open the port.
8953 NAME: balance_on_multiple_ip
8955 LOC: Config.onoff.balance_on_multiple_ip
8958 Modern IP resolvers in squid sort lookup results by preferred access.
8959 By default squid will use these IP in order and only rotates to
8960 the next listed when the most preffered fails.
8962 Some load balancing servers based on round robin DNS have been
8963 found not to preserve user session state across requests
8964 to different IP addresses.
8966 Enabling this directive Squid rotates IP's per request.
8969 NAME: pipeline_prefetch
8970 TYPE: pipelinePrefetch
8971 LOC: Config.pipeline_max_prefetch
8973 DEFAULT_DOC: Do not pre-parse pipelined requests.
8975 HTTP clients may send a pipeline of 1+N requests to Squid using a
8976 single connection, without waiting for Squid to respond to the first
8977 of those requests. This option limits the number of concurrent
8978 requests Squid will try to handle in parallel. If set to N, Squid
8979 will try to receive and process up to 1+N requests on the same
8980 connection concurrently.
8982 Defaults to 0 (off) for bandwidth management and access logging
8985 NOTE: pipelining requires persistent connections to clients.
8987 WARNING: pipelining breaks NTLM and Negotiate/Kerberos authentication.
8990 NAME: high_response_time_warning
8993 LOC: Config.warnings.high_rptm
8995 DEFAULT_DOC: disabled.
8997 If the one-minute median response time exceeds this value,
8998 Squid prints a WARNING with debug level 0 to get the
8999 administrators attention. The value is in milliseconds.
9002 NAME: high_page_fault_warning
9004 LOC: Config.warnings.high_pf
9006 DEFAULT_DOC: disabled.
9008 If the one-minute average page fault rate exceeds this
9009 value, Squid prints a WARNING with debug level 0 to get
9010 the administrators attention. The value is in page faults
9014 NAME: high_memory_warning
9016 LOC: Config.warnings.high_memory
9017 IFDEF: HAVE_MSTATS&&HAVE_GNUMALLOC_H
9019 DEFAULT_DOC: disabled.
9021 If the memory usage (as determined by gnumalloc, if available and used)
9022 exceeds this amount, Squid prints a WARNING with debug level 0 to get
9023 the administrators attention.
9025 # TODO: link high_memory_warning to mempools?
9027 NAME: sleep_after_fork
9028 COMMENT: (microseconds)
9030 LOC: Config.sleep_after_fork
9033 When this is set to a non-zero value, the main Squid process
9034 sleeps the specified number of microseconds after a fork()
9035 system call. This sleep may help the situation where your
9036 system reports fork() failures due to lack of (virtual)
9037 memory. Note, however, if you have a lot of child
9038 processes, these sleep delays will add up and your
9039 Squid will not service requests for some amount of time
9040 until all the child processes have been started.
9041 On Windows value less then 1000 (1 milliseconds) are
9045 NAME: windows_ipaddrchangemonitor
9046 IFDEF: _SQUID_WINDOWS_
9050 LOC: Config.onoff.WIN32_IpAddrChangeMonitor
9052 On Windows Squid by default will monitor IP address changes and will
9053 reconfigure itself after any detected event. This is very useful for
9054 proxies connected to internet with dial-up interfaces.
9055 In some cases (a Proxy server acting as VPN gateway is one) it could be
9056 desiderable to disable this behaviour setting this to 'off'.
9057 Note: after changing this, Squid service must be restarted.
9062 IFDEF: USE_SQUID_EUI
9064 LOC: Eui::TheConfig.euiLookup
9066 Whether to lookup the EUI or MAC address of a connected client.
9069 NAME: max_filedescriptors max_filedesc
9072 DEFAULT_DOC: Use operating system limits set by ulimit.
9073 LOC: Config.max_filedescriptors
9075 Reduce the maximum number of filedescriptors supported below
9076 the usual operating system defaults.
9078 Remove from squid.conf to inherit the current ulimit setting.
9080 Note: Changing this requires a restart of Squid. Also
9081 not all I/O types supports large values (eg on Windows).
9088 DEFAULT_DOC: SMP support disabled.
9090 Number of main Squid processes or "workers" to fork and maintain.
9091 0: "no daemon" mode, like running "squid -N ..."
9092 1: "no SMP" mode, start one main Squid process daemon (default)
9093 N: start N main Squid process daemons (i.e., SMP mode)
9095 In SMP mode, each worker does nearly all what a single Squid daemon
9096 does (e.g., listen on http_port and forward HTTP requests).
9099 NAME: cpu_affinity_map
9100 TYPE: CpuAffinityMap
9101 LOC: Config.cpuAffinityMap
9103 DEFAULT_DOC: Let operating system decide.
9105 Usage: cpu_affinity_map process_numbers=P1,P2,... cores=C1,C2,...
9107 Sets 1:1 mapping between Squid processes and CPU cores. For example,
9109 cpu_affinity_map process_numbers=1,2,3,4 cores=1,3,5,7
9111 affects processes 1 through 4 only and places them on the first
9112 four even cores, starting with core #1.
9114 CPU cores are numbered starting from 1. Requires support for
9115 sched_getaffinity(2) and sched_setaffinity(2) system calls.
9117 Multiple cpu_affinity_map options are merged.
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