2 # SQUID Web Proxy Cache http://www.squid-cache.org/
3 # ----------------------------------------------------------
5 # Squid is the result of efforts by numerous individuals from
6 # the Internet community; see the CONTRIBUTORS file for full
7 # details. Many organizations have provided support for Squid's
8 # development; see the SPONSORS file for full details. Squid is
9 # Copyrighted (C) 2000 by the Regents of the University of
10 # California; see the COPYRIGHT file for full details. Squid
11 # incorporates software developed and/or copyrighted by other
12 # sources; see the CREDITS file for full details.
14 # This program is free software; you can redistribute it and/or modify
15 # it under the terms of the GNU General Public License as published by
16 # the Free Software Foundation; either version 2 of the License, or
17 # (at your option) any later version.
19 # This program is distributed in the hope that it will be useful,
20 # but WITHOUT ANY WARRANTY; without even the implied warranty of
21 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 # GNU General Public License for more details.
24 # You should have received a copy of the GNU General Public License
25 # along with this program; if not, write to the Free Software
26 # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
31 ----------------------------
33 This is the documentation for the Squid configuration file.
34 This documentation can also be found online at:
35 http://www.squid-cache.org/Doc/config/
37 You may wish to look at the Squid home page and wiki for the
38 FAQ and other documentation:
39 http://www.squid-cache.org/
40 http://wiki.squid-cache.org/SquidFaq
41 http://wiki.squid-cache.org/ConfigExamples
43 This documentation shows what the defaults for various directives
44 happen to be. If you don't need to change the default, you should
45 leave the line out of your squid.conf in most cases.
47 In some cases "none" refers to no default setting at all,
48 while in other cases it refers to the value of the option
49 - the comments for that keyword indicate if this is the case.
54 Configuration options can be included using the "include" directive.
55 Include takes a list of files to include. Quoting and wildcards are
60 include /path/to/included/file/squid.acl.config
62 Includes can be nested up to a hard-coded depth of 16 levels.
63 This arbitrary restriction is to prevent recursive include references
64 from causing Squid entering an infinite loop whilst trying to load
68 Conditional configuration
70 If-statements can be used to make configuration directives
74 ... regular configuration directives ...
76 ... regular configuration directives ...]
79 The else part is optional. The keywords "if", "else", and "endif"
80 must be typed on their own lines, as if they were regular
81 configuration directives.
83 NOTE: An else-if condition is not supported.
85 These individual conditions types are supported:
88 Always evaluates to true.
90 Always evaluates to false.
92 Equality comparison of two integer numbers.
97 The following SMP-related preprocessor macros can be used.
99 ${process_name} expands to the current Squid process "name"
100 (e.g., squid1, squid2, or cache1).
102 ${process_number} expands to the current Squid process
103 identifier, which is an integer number (e.g., 1, 2, 3) unique
104 across all Squid processes.
107 # Options Removed in 3.2
108 NAME: ignore_expect_100
111 Remove this line. The HTTP/1.1 feature is now fully supported by default.
114 NAME: dns_v4_fallback
123 Remove this line. Configure FTP page display using the CSS controls in errorpages.css instead.
126 NAME: url_rewrite_concurrency
129 Remove this line. Set the 'concurrency=' option of url_rewrite_children instead.
132 # Options Removed in 3.1
136 Remove this line. DNS is no longer tested on startup.
139 NAME: extension_methods
142 Remove this line. All valid methods for HTTP are accepted by default.
145 # 2.7 Options Removed/Replaced in 3.1
153 Remove this line. HTTP/1.1 is supported by default.
156 NAME: upgrade_http0.9
159 Remove this line. ICY/1.0 streaming protocol is supported by default.
162 NAME: zph_local zph_mode zph_option zph_parent zph_sibling
165 Alter these entries. Use the qos_flows directive instead.
168 # Options Removed in 3.0
172 Since squid-3.0 replace with request_header_access or reply_header_access
173 depending on whether you wish to match client requests or server replies.
176 NAME: httpd_accel_no_pmtu_disc
179 Since squid-3.0 use the 'disable-pmtu-discovery' flag on http_port instead.
183 OPTIONS FOR AUTHENTICATION
184 -----------------------------------------------------------------------------
193 This is used to define parameters for the various authentication
194 schemes supported by Squid.
196 format: auth_param scheme parameter [setting]
198 The order in which authentication schemes are presented to the client is
199 dependent on the order the scheme first appears in config file. IE
200 has a bug (it's not RFC 2617 compliant) in that it will use the basic
201 scheme if basic is the first entry presented, even if more secure
202 schemes are presented. For now use the order in the recommended
203 settings section below. If other browsers have difficulties (don't
204 recognize the schemes offered even if you are using basic) either
205 put basic first, or disable the other schemes (by commenting out their
208 Once an authentication scheme is fully configured, it can only be
209 shutdown by shutting squid down and restarting. Changes can be made on
210 the fly and activated with a reconfigure. I.E. You can change to a
211 different helper, but not unconfigure the helper completely.
213 Please note that while this directive defines how Squid processes
214 authentication it does not automatically activate authentication.
215 To use authentication you must in addition make use of ACLs based
216 on login name in http_access (proxy_auth, proxy_auth_regex or
217 external with %LOGIN used in the format tag). The browser will be
218 challenged for authentication on the first such acl encountered
219 in http_access processing and will also be re-challenged for new
220 login credentials if the request is being denied by a proxy_auth
223 WARNING: authentication can't be used in a transparently intercepting
224 proxy as the client then thinks it is talking to an origin server and
225 not the proxy. This is a limitation of bending the TCP/IP protocol to
226 transparently intercepting port 80, not a limitation in Squid.
227 Ports flagged 'transparent', 'intercept', or 'tproxy' have
228 authentication disabled.
230 === Parameters for the basic scheme follow. ===
233 Specify the command for the external authenticator. Such a program
234 reads a line containing "username password" and replies "OK" or
235 "ERR" in an endless loop. "ERR" responses may optionally be followed
236 by a error description available as %m in the returned error page.
237 If you use an authenticator, make sure you have 1 acl of type
240 By default, the basic authentication scheme is not used unless a
241 program is specified.
243 If you want to use the traditional NCSA proxy authentication, set
244 this line to something like
246 auth_param basic program @DEFAULT_PREFIX@/libexec/ncsa_auth @DEFAULT_PREFIX@/etc/passwd
249 HTTP uses iso-latin-1 as characterset, while some authentication
250 backends such as LDAP expects UTF-8. If this is set to on Squid will
251 translate the HTTP iso-latin-1 charset to UTF-8 before sending the
252 username & password to the helper.
254 "children" numberofchildren [startup=N] [idle=N] [concurrency=N]
255 The maximum number of authenticator processes to spawn. If you start too few
256 Squid will have to wait for them to process a backlog of credential
257 verifications, slowing it down. When password verifications are
258 done via a (slow) network you are likely to need lots of
259 authenticator processes.
261 The startup= and idle= options permit some skew in the exact amount
262 run. A minimum of startup=N will begin during startup and reconfigure.
263 Squid will start more in groups of up to idle=N in an attempt to meet
264 traffic needs and to keep idle=N free above those traffic needs up to
267 The concurrency= option sets the number of concurrent requests the
268 helper can process. The default of 0 is used for helpers who only
269 supports one request at a time. Setting this to a number greater than
270 0 changes the protocol used to include a channel number first on the
271 request/response line, allowing multiple requests to be sent to the
272 same helper in parallell without wating for the response.
273 Must not be set unless it's known the helper supports this.
275 auth_param basic children 20 startup=0 idle=1
278 Specifies the realm name which is to be reported to the
279 client for the basic proxy authentication scheme (part of
280 the text the user will see when prompted their username and
281 password). There is no default.
282 auth_param basic realm Squid proxy-caching web server
284 "credentialsttl" timetolive
285 Specifies how long squid assumes an externally validated
286 username:password pair is valid for - in other words how
287 often the helper program is called for that user. Set this
288 low to force revalidation with short lived passwords. Note
289 setting this high does not impact your susceptibility
290 to replay attacks unless you are using an one-time password
291 system (such as SecureID). If you are using such a system,
292 you will be vulnerable to replay attacks unless you also
293 use the max_user_ip ACL in an http_access rule.
295 "casesensitive" on|off
296 Specifies if usernames are case sensitive. Most user databases are
297 case insensitive allowing the same username to be spelled using both
298 lower and upper case letters, but some are case sensitive. This
299 makes a big difference for user_max_ip ACL processing and similar.
300 auth_param basic casesensitive off
302 === Parameters for the digest scheme follow ===
305 Specify the command for the external authenticator. Such
306 a program reads a line containing "username":"realm" and
307 replies with the appropriate H(A1) value hex encoded or
308 ERR if the user (or his H(A1) hash) does not exists.
309 See rfc 2616 for the definition of H(A1).
310 "ERR" responses may optionally be followed by a error description
311 available as %m in the returned error page.
313 By default, the digest authentication scheme is not used unless a
314 program is specified.
316 If you want to use a digest authenticator, set this line to
319 auth_param digest program @DEFAULT_PREFIX@/bin/digest_pw_auth @DEFAULT_PREFIX@/etc/digpass
322 HTTP uses iso-latin-1 as characterset, while some authentication
323 backends such as LDAP expects UTF-8. If this is set to on Squid will
324 translate the HTTP iso-latin-1 charset to UTF-8 before sending the
325 username & password to the helper.
327 "children" numberofchildren [startup=N] [idle=N] [concurrency=N]
328 The maximum number of authenticator processes to spawn (default 5).
329 If you start too few Squid will have to wait for them to
330 process a backlog of H(A1) calculations, slowing it down.
331 When the H(A1) calculations are done via a (slow) network
332 you are likely to need lots of authenticator processes.
334 The startup= and idle= options permit some skew in the exact amount
335 run. A minimum of startup=N will begin during startup and reconfigure.
336 Squid will start more in groups of up to idle=N in an attempt to meet
337 traffic needs and to keep idle=N free above those traffic needs up to
340 The concurrency= option sets the number of concurrent requests the
341 helper can process. The default of 0 is used for helpers who only
342 supports one request at a time. Setting this to a number greater than
343 0 changes the protocol used to include a channel number first on the
344 request/response line, allowing multiple requests to be sent to the
345 same helper in parallell without wating for the response.
346 Must not be set unless it's known the helper supports this.
348 auth_param digest children 20 startup=0 idle=1
351 Specifies the realm name which is to be reported to the
352 client for the digest proxy authentication scheme (part of
353 the text the user will see when prompted their username and
354 password). There is no default.
355 auth_param digest realm Squid proxy-caching web server
357 "nonce_garbage_interval" timeinterval
358 Specifies the interval that nonces that have been issued
359 to client_agent's are checked for validity.
361 "nonce_max_duration" timeinterval
362 Specifies the maximum length of time a given nonce will be
365 "nonce_max_count" number
366 Specifies the maximum number of times a given nonce can be
369 "nonce_strictness" on|off
370 Determines if squid requires strict increment-by-1 behavior
371 for nonce counts, or just incrementing (off - for use when
372 useragents generate nonce counts that occasionally miss 1
373 (ie, 1,2,4,6)). Default off.
375 "check_nonce_count" on|off
376 This directive if set to off can disable the nonce count check
377 completely to work around buggy digest qop implementations in
378 certain mainstream browser versions. Default on to check the
379 nonce count to protect from authentication replay attacks.
381 "post_workaround" on|off
382 This is a workaround to certain buggy browsers who sends
383 an incorrect request digest in POST requests when reusing
384 the same nonce as acquired earlier on a GET request.
386 === NTLM scheme options follow ===
389 Specify the command for the external NTLM authenticator.
390 Such a program reads exchanged NTLMSSP packets with
391 the browser via Squid until authentication is completed.
392 If you use an NTLM authenticator, make sure you have 1 acl
393 of type proxy_auth. By default, the NTLM authenticator_program
396 auth_param ntlm program @DEFAULT_PREFIX@/bin/ntlm_auth
398 "children" numberofchildren [startup=N] [idle=N]
399 The maximum number of authenticator processes to spawn (default 5).
400 If you start too few Squid will have to wait for them to
401 process a backlog of credential verifications, slowing it
402 down. When credential verifications are done via a (slow)
403 network you are likely to need lots of authenticator
406 The startup= and idle= options permit some skew in the exact amount
407 run. A minimum of startup=N will begin during startup and reconfigure.
408 Squid will start more in groups of up to idle=N in an attempt to meet
409 traffic needs and to keep idle=N free above those traffic needs up to
412 auth_param ntlm children 20 startup=0 idle=1
415 If you experience problems with PUT/POST requests when using the
416 Negotiate authentication scheme then you can try setting this to
417 off. This will cause Squid to forcibly close the connection on
418 the initial requests where the browser asks which schemes are
419 supported by the proxy.
421 auth_param ntlm keep_alive on
423 === Options for configuring the NEGOTIATE auth-scheme follow ===
426 Specify the command for the external Negotiate authenticator.
427 This protocol is used in Microsoft Active-Directory enabled setups with
428 the Microsoft Internet Explorer or Mozilla Firefox browsers.
429 Its main purpose is to exchange credentials with the Squid proxy
430 using the Kerberos mechanisms.
431 If you use a Negotiate authenticator, make sure you have at least
432 one acl of type proxy_auth active. By default, the negotiate
433 authenticator_program is not used.
434 The only supported program for this role is the ntlm_auth
435 program distributed as part of Samba, version 4 or later.
437 auth_param negotiate program @DEFAULT_PREFIX@/bin/ntlm_auth --helper-protocol=gss-spnego
439 "children" numberofchildren [startup=N] [idle=N]
440 The maximum number of authenticator processes to spawn (default 5).
441 If you start too few Squid will have to wait for them to
442 process a backlog of credential verifications, slowing it
443 down. When crendential verifications are done via a (slow)
444 network you are likely to need lots of authenticator
447 The startup= and idle= options permit some skew in the exact amount
448 run. A minimum of startup=N will begin during startup and reconfigure.
449 Squid will start more in groups of up to idle=N in an attempt to meet
450 traffic needs and to keep idle=N free above those traffic needs up to
453 auth_param negotiate children 20 startup=0 idle=1
456 If you experience problems with PUT/POST requests when using the
457 Negotiate authentication scheme then you can try setting this to
458 off. This will cause Squid to forcibly close the connection on
459 the initial requests where the browser asks which schemes are
460 supported by the proxy.
462 auth_param negotiate keep_alive on
467 #Recommended minimum configuration per scheme:
468 #auth_param negotiate program <uncomment and complete this line to activate>
469 #auth_param negotiate children 20 startup=0 idle=1
470 #auth_param negotiate keep_alive on
472 #auth_param ntlm program <uncomment and complete this line to activate>
473 #auth_param ntlm children 20 startup=0 idle=1
474 #auth_param ntlm keep_alive on
476 #auth_param digest program <uncomment and complete this line>
477 #auth_param digest children 20 startup=0 idle=1
478 #auth_param digest realm Squid proxy-caching web server
479 #auth_param digest nonce_garbage_interval 5 minutes
480 #auth_param digest nonce_max_duration 30 minutes
481 #auth_param digest nonce_max_count 50
483 #auth_param basic program <uncomment and complete this line>
484 #auth_param basic children 5 startup=5 idle=1
485 #auth_param basic realm Squid proxy-caching web server
486 #auth_param basic credentialsttl 2 hours
489 NAME: authenticate_cache_garbage_interval
492 LOC: Config.authenticateGCInterval
494 The time period between garbage collection across the username cache.
495 This is a tradeoff between memory utilization (long intervals - say
496 2 days) and CPU (short intervals - say 1 minute). Only change if you
500 NAME: authenticate_ttl
503 LOC: Config.authenticateTTL
505 The time a user & their credentials stay in the logged in
506 user cache since their last request. When the garbage
507 interval passes, all user credentials that have passed their
508 TTL are removed from memory.
511 NAME: authenticate_ip_ttl
513 LOC: Config.authenticateIpTTL
516 If you use proxy authentication and the 'max_user_ip' ACL,
517 this directive controls how long Squid remembers the IP
518 addresses associated with each user. Use a small value
519 (e.g., 60 seconds) if your users might change addresses
520 quickly, as is the case with dialups. You might be safe
521 using a larger value (e.g., 2 hours) in a corporate LAN
522 environment with relatively static address assignments.
527 -----------------------------------------------------------------------------
530 NAME: external_acl_type
531 TYPE: externalAclHelper
532 LOC: Config.externalAclHelperList
535 This option defines external acl classes using a helper program
536 to look up the status
538 external_acl_type name [options] FORMAT.. /path/to/helper [helper arguments..]
542 ttl=n TTL in seconds for cached results (defaults to 3600
545 TTL for cached negative lookups (default same
548 Maximum number of acl helper processes spawned to service
549 external acl lookups of this type. (default 20)
551 Minimum number of acl helper processes to spawn during
552 startup and reconfigure to service external acl lookups
553 of this type. (default 0)
555 Number of acl helper processes to keep ahead of traffic
556 loads. Squid will spawn this many at once whenever load
557 rises above the capabilities of existing processes.
558 Up to the value of children-max. (default 1)
559 concurrency=n concurrency level per process. Only used with helpers
560 capable of processing more than one query at a time.
561 cache=n limit the result cache size, default is unbounded.
562 grace=n Percentage remaining of TTL where a refresh of a
563 cached entry should be initiated without needing to
564 wait for a new reply. (default is for no grace period)
565 protocol=2.5 Compatibility mode for Squid-2.5 external acl helpers
566 ipv4 / ipv6 IP protocol used to communicate with this helper.
567 The default is to auto-detect IPv6 and use it when available.
569 FORMAT specifications
571 %LOGIN Authenticated user login name
572 %EXT_USER Username from previous external acl
573 %EXT_LOG Log details from previous external acl
574 %EXT_TAG Tag from previous external acl
575 %IDENT Ident user name
577 %SRCPORT Client source port
580 %PROTO Requested protocol
582 %PATH Requested URL path
583 %METHOD Request method
584 %MYADDR Squid interface address
585 %MYPORT Squid http_port number
586 %PATH Requested URL-path (including query-string if any)
587 %USER_CERT SSL User certificate in PEM format
588 %USER_CERTCHAIN SSL User certificate chain in PEM format
589 %USER_CERT_xx SSL User certificate subject attribute xx
590 %USER_CA_xx SSL User certificate issuer attribute xx
592 %>{Header} HTTP request header "Header"
594 HTTP request header "Hdr" list member "member"
596 HTTP request header list member using ; as
597 list separator. ; can be any non-alphanumeric
600 %<{Header} HTTP reply header "Header"
602 HTTP reply header "Hdr" list member "member"
604 HTTP reply header list member using ; as
605 list separator. ; can be any non-alphanumeric
608 %% The percent sign. Useful for helpers which need
609 an unchanging input format.
611 In addition to the above, any string specified in the referencing
612 acl will also be included in the helper request line, after the
613 specified formats (see the "acl external" directive)
615 The helper receives lines per the above format specification,
616 and returns lines starting with OK or ERR indicating the validity
617 of the request and optionally followed by additional keywords with
620 General result syntax:
622 OK/ERR keyword=value ...
626 user= The users name (login)
627 password= The users password (for login= cache_peer option)
628 message= Message describing the reason. Available as %o
630 tag= Apply a tag to a request (for both ERR and OK results)
631 Only sets a tag, does not alter existing tags.
632 log= String to be logged in access.log. Available as
633 %ea in logformat specifications
635 If protocol=3.0 (the default) then URL escaping is used to protect
636 each value in both requests and responses.
638 If using protocol=2.5 then all values need to be enclosed in quotes
639 if they may contain whitespace, or the whitespace escaped using \.
640 And quotes or \ characters within the keyword value must be \ escaped.
642 When using the concurrency= option the protocol is changed by
643 introducing a query channel tag infront of the request/response.
644 The query channel tag is a number between 0 and concurrency-1.
651 DEFAULT: manager url_regex -i ^cache_object:// +i ^https?://[^/]+/squid-internal-mgr/
652 DEFAULT: localhost src 127.0.0.1/32 ::1
653 DEFAULT: to_localhost dst 127.0.0.0/8 0.0.0.0/32 ::1
654 DEFAULT_DOC: ACLs all, manager, localhost, and to_localhost are predefined.
656 Defining an Access List
658 Every access list definition must begin with an aclname and acltype,
659 followed by either type-specific arguments or a quoted filename that
662 acl aclname acltype argument ...
663 acl aclname acltype "file" ...
665 When using "file", the file should contain one item per line.
667 By default, regular expressions are CASE-SENSITIVE.
668 To make them case-insensitive, use the -i option. To return case-sensitive
669 use the +i option between patterns, or make a new ACL line without -i.
671 Some acl types require suspending the current request in order
672 to access some external data source.
673 Those which do are marked with the tag [slow], those which
674 don't are marked as [fast].
675 See http://wiki.squid-cache.org/SquidFaq/SquidAcl
676 for further information
678 ***** ACL TYPES AVAILABLE *****
680 acl aclname src ip-address/mask ... # clients IP address [fast]
681 acl aclname src addr1-addr2/mask ... # range of addresses [fast]
682 acl aclname dst ip-address/mask ... # URL host's IP address [slow]
683 acl aclname localip ip-address/mask ... # IP address the client connected to [fast]
685 acl aclname arp mac-address ... (xx:xx:xx:xx:xx:xx notation)
686 # The arp ACL requires the special configure option --enable-arp-acl.
687 # Furthermore, the ARP ACL code is not portable to all operating systems.
688 # It works on Linux, Solaris, Windows, FreeBSD, and some
689 # other *BSD variants.
692 # NOTE: Squid can only determine the MAC address for clients that are on
693 # the same subnet. If the client is on a different subnet,
694 # then Squid cannot find out its MAC address.
696 acl aclname srcdomain .foo.com ...
697 # reverse lookup, from client IP [slow]
698 acl aclname dstdomain .foo.com ...
699 # Destination server from URL [fast]
700 acl aclname srcdom_regex [-i] \.foo\.com ...
701 # regex matching client name [slow]
702 acl aclname dstdom_regex [-i] \.foo\.com ...
703 # regex matching server [fast]
705 # For dstdomain and dstdom_regex a reverse lookup is tried if a IP
706 # based URL is used and no match is found. The name "none" is used
707 # if the reverse lookup fails.
709 acl aclname src_as number ...
710 acl aclname dst_as number ...
712 # Except for access control, AS numbers can be used for
713 # routing of requests to specific caches. Here's an
714 # example for routing all requests for AS#1241 and only
715 # those to mycache.mydomain.net:
716 # acl asexample dst_as 1241
717 # cache_peer_access mycache.mydomain.net allow asexample
718 # cache_peer_access mycache_mydomain.net deny all
720 acl aclname peername myPeer ...
722 # match against a named cache_peer entry
723 # set unique name= on cache_peer lines for reliable use.
725 acl aclname time [day-abbrevs] [h1:m1-h2:m2]
735 # h1:m1 must be less than h2:m2
737 acl aclname url_regex [-i] ^http:// ...
738 # regex matching on whole URL [fast]
739 acl aclname urlpath_regex [-i] \.gif$ ...
740 # regex matching on URL path [fast]
742 acl aclname port 80 70 21 0-1024... # destination TCP port [fast]
744 acl aclname localport 3128 ... # TCP port the client connected to [fast]
745 # NP: for interception mode this is usually '80'
747 acl aclname myportname 3128 ... # http(s)_port name [fast]
749 acl aclname proto HTTP FTP ... # request protocol [fast]
751 acl aclname method GET POST ... # HTTP request method [fast]
753 acl aclname http_status 200 301 500- 400-403 ...
754 # status code in reply [fast]
756 acl aclname browser [-i] regexp ...
757 # pattern match on User-Agent header (see also req_header below) [fast]
759 acl aclname referer_regex [-i] regexp ...
760 # pattern match on Referer header [fast]
761 # Referer is highly unreliable, so use with care
763 acl aclname ident username ...
764 acl aclname ident_regex [-i] pattern ...
765 # string match on ident output [slow]
766 # use REQUIRED to accept any non-null ident.
768 acl aclname proxy_auth [-i] username ...
769 acl aclname proxy_auth_regex [-i] pattern ...
770 # perform http authentication challenge to the client and match against
771 # supplied credentials [slow]
773 # takes a list of allowed usernames.
774 # use REQUIRED to accept any valid username.
776 # Will use proxy authentication in forward-proxy scenarios, and plain
777 # http authenticaiton in reverse-proxy scenarios
779 # NOTE: when a Proxy-Authentication header is sent but it is not
780 # needed during ACL checking the username is NOT logged
783 # NOTE: proxy_auth requires a EXTERNAL authentication program
784 # to check username/password combinations (see
785 # auth_param directive).
787 # NOTE: proxy_auth can't be used in a transparent/intercepting proxy
788 # as the browser needs to be configured for using a proxy in order
789 # to respond to proxy authentication.
791 acl aclname snmp_community string ...
792 # A community string to limit access to your SNMP Agent [fast]
795 # acl snmppublic snmp_community public
797 acl aclname maxconn number
798 # This will be matched when the client's IP address has
799 # more than <number> TCP connections established. [fast]
800 # NOTE: This only measures direct TCP links so X-Forwarded-For
801 # indirect clients are not counted.
803 acl aclname max_user_ip [-s] number
804 # This will be matched when the user attempts to log in from more
805 # than <number> different ip addresses. The authenticate_ip_ttl
806 # parameter controls the timeout on the ip entries. [fast]
807 # If -s is specified the limit is strict, denying browsing
808 # from any further IP addresses until the ttl has expired. Without
809 # -s Squid will just annoy the user by "randomly" denying requests.
810 # (the counter is reset each time the limit is reached and a
812 # NOTE: in acceleration mode or where there is mesh of child proxies,
813 # clients may appear to come from multiple addresses if they are
814 # going through proxy farms, so a limit of 1 may cause user problems.
816 acl aclname random probability
817 # Pseudo-randomly match requests. Based on the probability given.
818 # Probability may be written as a decimal (0.333), fraction (1/3)
819 # or ratio of matches:non-matches (3:5).
821 acl aclname req_mime_type [-i] mime-type ...
822 # regex match against the mime type of the request generated
823 # by the client. Can be used to detect file upload or some
824 # types HTTP tunneling requests [fast]
825 # NOTE: This does NOT match the reply. You cannot use this
826 # to match the returned file type.
828 acl aclname req_header header-name [-i] any\.regex\.here
829 # regex match against any of the known request headers. May be
830 # thought of as a superset of "browser", "referer" and "mime-type"
833 acl aclname rep_mime_type [-i] mime-type ...
834 # regex match against the mime type of the reply received by
835 # squid. Can be used to detect file download or some
836 # types HTTP tunneling requests. [fast]
837 # NOTE: This has no effect in http_access rules. It only has
838 # effect in rules that affect the reply data stream such as
841 acl aclname rep_header header-name [-i] any\.regex\.here
842 # regex match against any of the known reply headers. May be
843 # thought of as a superset of "browser", "referer" and "mime-type"
846 acl aclname external class_name [arguments...]
847 # external ACL lookup via a helper class defined by the
848 # external_acl_type directive [slow]
850 acl aclname user_cert attribute values...
851 # match against attributes in a user SSL certificate
852 # attribute is one of DN/C/O/CN/L/ST [fast]
854 acl aclname ca_cert attribute values...
855 # match against attributes a users issuing CA SSL certificate
856 # attribute is one of DN/C/O/CN/L/ST [fast]
858 acl aclname ext_user username ...
859 acl aclname ext_user_regex [-i] pattern ...
860 # string match on username returned by external acl helper [slow]
861 # use REQUIRED to accept any non-null user name.
863 acl aclname tag tagvalue ...
864 # string match on tag returned by external acl helper [slow]
866 acl aclname hier_code codename ...
867 # string match against squid hierarchy code(s); [fast]
868 # e.g., DIRECT, PARENT_HIT, NONE, etc.
870 # NOTE: This has no effect in http_access rules. It only has
871 # effect in rules that affect the reply data stream such as
875 acl macaddress arp 09:00:2b:23:45:67
876 acl myexample dst_as 1241
877 acl password proxy_auth REQUIRED
878 acl fileupload req_mime_type -i ^multipart/form-data$
879 acl javascript rep_mime_type -i ^application/x-javascript$
883 # Recommended minimum configuration:
886 # Example rule allowing access from your local networks.
887 # Adapt to list your (internal) IP networks from where browsing
889 acl localnet src 10.0.0.0/8 # RFC1918 possible internal network
890 acl localnet src 172.16.0.0/12 # RFC1918 possible internal network
891 acl localnet src 192.168.0.0/16 # RFC1918 possible internal network
892 acl localnet src fc00::/7 # RFC 4193 local private network range
893 acl localnet src fe80::/10 # RFC 4291 link-local (directly plugged) machines
895 acl SSL_ports port 443
896 acl Safe_ports port 80 # http
897 acl Safe_ports port 21 # ftp
898 acl Safe_ports port 443 # https
899 acl Safe_ports port 70 # gopher
900 acl Safe_ports port 210 # wais
901 acl Safe_ports port 1025-65535 # unregistered ports
902 acl Safe_ports port 280 # http-mgmt
903 acl Safe_ports port 488 # gss-http
904 acl Safe_ports port 591 # filemaker
905 acl Safe_ports port 777 # multiling http
906 acl CONNECT method CONNECT
910 NAME: follow_x_forwarded_for
912 IFDEF: FOLLOW_X_FORWARDED_FOR
913 LOC: Config.accessList.followXFF
914 DEFAULT_IF_NONE: deny all
916 Allowing or Denying the X-Forwarded-For header to be followed to
917 find the original source of a request.
919 Requests may pass through a chain of several other proxies
920 before reaching us. The X-Forwarded-For header will contain a
921 comma-separated list of the IP addresses in the chain, with the
922 rightmost address being the most recent.
924 If a request reaches us from a source that is allowed by this
925 configuration item, then we consult the X-Forwarded-For header
926 to see where that host received the request from. If the
927 X-Forwarded-For header contains multiple addresses, we continue
928 backtracking until we reach an address for which we are not allowed
929 to follow the X-Forwarded-For header, or until we reach the first
930 address in the list. For the purpose of ACL used in the
931 follow_x_forwarded_for directive the src ACL type always matches
932 the address we are testing and srcdomain matches its rDNS.
934 The end result of this process is an IP address that we will
935 refer to as the indirect client address. This address may
936 be treated as the client address for access control, ICAP, delay
937 pools and logging, depending on the acl_uses_indirect_client,
938 icap_uses_indirect_client, delay_pool_uses_indirect_client,
939 log_uses_indirect_client and tproxy_uses_indirect_client options.
941 This clause only supports fast acl types.
942 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
944 SECURITY CONSIDERATIONS:
946 Any host for which we follow the X-Forwarded-For header
947 can place incorrect information in the header, and Squid
948 will use the incorrect information as if it were the
949 source address of the request. This may enable remote
950 hosts to bypass any access control restrictions that are
951 based on the client's source addresses.
955 acl localhost src 127.0.0.1
956 acl my_other_proxy srcdomain .proxy.example.com
957 follow_x_forwarded_for allow localhost
958 follow_x_forwarded_for allow my_other_proxy
961 NAME: acl_uses_indirect_client
964 IFDEF: FOLLOW_X_FORWARDED_FOR
966 LOC: Config.onoff.acl_uses_indirect_client
968 Controls whether the indirect client address
969 (see follow_x_forwarded_for) is used instead of the
970 direct client address in acl matching.
972 NOTE: maxconn ACL considers direct TCP links and indirect
973 clients will always have zero. So no match.
976 NAME: delay_pool_uses_indirect_client
979 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_DELAY_POOLS
981 LOC: Config.onoff.delay_pool_uses_indirect_client
983 Controls whether the indirect client address
984 (see follow_x_forwarded_for) is used instead of the
985 direct client address in delay pools.
988 NAME: log_uses_indirect_client
991 IFDEF: FOLLOW_X_FORWARDED_FOR
993 LOC: Config.onoff.log_uses_indirect_client
995 Controls whether the indirect client address
996 (see follow_x_forwarded_for) is used instead of the
997 direct client address in the access log.
1000 NAME: tproxy_uses_indirect_client
1003 IFDEF: FOLLOW_X_FORWARDED_FOR&&LINUX_NETFILTER
1005 LOC: Config.onoff.tproxy_uses_indirect_client
1007 Controls whether the indirect client address
1008 (see follow_x_forwarded_for) is used instead of the
1009 direct client address when spoofing the outgoing client.
1011 This has no effect on requests arriving in non-tproxy
1014 SECURITY WARNING: Usage of this option is dangerous
1015 and should not be used trivially. Correct configuration
1016 of follow_x_forewarded_for with a limited set of trusted
1017 sources is required to prevent abuse of your proxy.
1022 LOC: Config.accessList.http
1023 DEFAULT_IF_NONE: deny all
1025 Allowing or Denying access based on defined access lists
1027 Access to the HTTP port:
1028 http_access allow|deny [!]aclname ...
1030 NOTE on default values:
1032 If there are no "access" lines present, the default is to deny
1035 If none of the "access" lines cause a match, the default is the
1036 opposite of the last line in the list. If the last line was
1037 deny, the default is allow. Conversely, if the last line
1038 is allow, the default will be deny. For these reasons, it is a
1039 good idea to have an "deny all" entry at the end of your access
1040 lists to avoid potential confusion.
1042 This clause supports both fast and slow acl types.
1043 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1048 # Recommended minimum Access Permission configuration:
1050 # Only allow cachemgr access from localhost
1051 http_access allow localhost manager
1052 http_access deny manager
1054 # Deny requests to certain unsafe ports
1055 http_access deny !Safe_ports
1057 # Deny CONNECT to other than secure SSL ports
1058 http_access deny CONNECT !SSL_ports
1060 # We strongly recommend the following be uncommented to protect innocent
1061 # web applications running on the proxy server who think the only
1062 # one who can access services on "localhost" is a local user
1063 #http_access deny to_localhost
1066 # INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS
1069 # Example rule allowing access from your local networks.
1070 # Adapt localnet in the ACL section to list your (internal) IP networks
1071 # from where browsing should be allowed
1072 http_access allow localnet
1073 http_access allow localhost
1075 # And finally deny all other access to this proxy
1076 http_access deny all
1080 NAME: adapted_http_access http_access2
1082 LOC: Config.accessList.adapted_http
1085 Allowing or Denying access based on defined access lists
1087 Essentially identical to http_access, but runs after redirectors
1088 and ICAP/eCAP adaptation. Allowing access control based on their
1091 If not set then only http_access is used.
1094 NAME: http_reply_access
1096 LOC: Config.accessList.reply
1099 Allow replies to client requests. This is complementary to http_access.
1101 http_reply_access allow|deny [!] aclname ...
1103 NOTE: if there are no access lines present, the default is to allow
1106 If none of the access lines cause a match the opposite of the
1107 last line will apply. Thus it is good practice to end the rules
1108 with an "allow all" or "deny all" entry.
1110 This clause supports both fast and slow acl types.
1111 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1116 LOC: Config.accessList.icp
1117 DEFAULT_IF_NONE: deny all
1119 Allowing or Denying access to the ICP port based on defined
1122 icp_access allow|deny [!]aclname ...
1124 See http_access for details
1126 This clause only supports fast acl types.
1127 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1129 # Allow ICP queries from local networks only
1130 #icp_access allow localnet
1131 #icp_access deny all
1137 LOC: Config.accessList.htcp
1138 DEFAULT_IF_NONE: deny all
1140 Allowing or Denying access to the HTCP port based on defined
1143 htcp_access allow|deny [!]aclname ...
1145 See http_access for details
1147 NOTE: The default if no htcp_access lines are present is to
1148 deny all traffic. This default may cause problems with peers
1149 using the htcp option.
1151 This clause only supports fast acl types.
1152 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1154 # Allow HTCP queries from local networks only
1155 #htcp_access allow localnet
1156 #htcp_access deny all
1159 NAME: htcp_clr_access
1162 LOC: Config.accessList.htcp_clr
1163 DEFAULT_IF_NONE: deny all
1165 Allowing or Denying access to purge content using HTCP based
1166 on defined access lists
1168 htcp_clr_access allow|deny [!]aclname ...
1170 See http_access for details
1172 This clause only supports fast acl types.
1173 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1175 # Allow HTCP CLR requests from trusted peers
1176 acl htcp_clr_peer src 172.16.1.2
1177 htcp_clr_access allow htcp_clr_peer
1182 LOC: Config.accessList.miss
1185 Determins whether network access is permitted when satisfying a request.
1188 to force your neighbors to use you as a sibling instead of
1191 acl localclients src 172.16.0.0/16
1192 miss_access allow localclients
1193 miss_access deny !localclients
1195 This means only your local clients are allowed to fetch relayed/MISS
1196 replies from the network and all other clients can only fetch cached
1200 The default for this setting allows all clients who passed the
1201 http_access rules to relay via this proxy.
1203 This clause only supports fast acl types.
1204 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1207 NAME: ident_lookup_access
1210 DEFAULT_IF_NONE: deny all
1211 LOC: Ident::TheConfig.identLookup
1213 A list of ACL elements which, if matched, cause an ident
1214 (RFC 931) lookup to be performed for this request. For
1215 example, you might choose to always perform ident lookups
1216 for your main multi-user Unix boxes, but not for your Macs
1217 and PCs. By default, ident lookups are not performed for
1220 To enable ident lookups for specific client addresses, you
1221 can follow this example:
1223 acl ident_aware_hosts src 198.168.1.0/24
1224 ident_lookup_access allow ident_aware_hosts
1225 ident_lookup_access deny all
1227 Only src type ACL checks are fully supported. A srcdomain
1228 ACL might work at times, but it will not always provide
1231 This clause only supports fast acl types.
1232 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1235 NAME: reply_body_max_size
1236 COMMENT: size [acl acl...]
1239 LOC: Config.ReplyBodySize
1241 This option specifies the maximum size of a reply body. It can be
1242 used to prevent users from downloading very large files, such as
1243 MP3's and movies. When the reply headers are received, the
1244 reply_body_max_size lines are processed, and the first line where
1245 all (if any) listed ACLs are true is used as the maximum body size
1248 This size is checked twice. First when we get the reply headers,
1249 we check the content-length value. If the content length value exists
1250 and is larger than the allowed size, the request is denied and the
1251 user receives an error message that says "the request or reply
1252 is too large." If there is no content-length, and the reply
1253 size exceeds this limit, the client's connection is just closed
1254 and they will receive a partial reply.
1256 WARNING: downstream caches probably can not detect a partial reply
1257 if there is no content-length header, so they will cache
1258 partial responses and give them out as hits. You should NOT
1259 use this option if you have downstream caches.
1261 WARNING: A maximum size smaller than the size of squid's error messages
1262 will cause an infinite loop and crash squid. Ensure that the smallest
1263 non-zero value you use is greater that the maximum header size plus
1264 the size of your largest error page.
1266 If you set this parameter none (the default), there will be
1269 Configuration Format is:
1270 reply_body_max_size SIZE UNITS [acl ...]
1272 reply_body_max_size 10 MB
1278 -----------------------------------------------------------------------------
1281 NAME: http_port ascii_port
1282 TYPE: http_port_list
1284 LOC: Config.Sockaddr.http
1286 Usage: port [mode] [options]
1287 hostname:port [mode] [options]
1288 1.2.3.4:port [mode] [options]
1290 The socket addresses where Squid will listen for HTTP client
1291 requests. You may specify multiple socket addresses.
1292 There are three forms: port alone, hostname with port, and
1293 IP address with port. If you specify a hostname or IP
1294 address, Squid binds the socket to that specific
1295 address. Most likely, you do not need to bind to a specific
1296 address, so you can use the port number alone.
1298 If you are running Squid in accelerator mode, you
1299 probably want to listen on port 80 also, or instead.
1301 The -a command line option may be used to specify additional
1302 port(s) where Squid listens for proxy request. Such ports will
1303 be plain proxy ports with no options.
1305 You may specify multiple socket addresses on multiple lines.
1309 intercept Support for IP-Layer interception of
1310 outgoing requests without browser settings.
1311 NP: disables authentication and IPv6 on the port.
1313 tproxy Support Linux TPROXY for spoofing outgoing
1314 connections using the client IP address.
1315 NP: disables authentication and maybe IPv6 on the port.
1317 accel Accelerator / reverse proxy mode
1319 ssl-bump Intercept each CONNECT request matching ssl_bump ACL,
1320 establish secure connection with the client and with
1321 the server, decrypt HTTP messages as they pass through
1322 Squid, and treat them as unencrypted HTTP messages,
1323 becoming the man-in-the-middle.
1325 The ssl_bump option is required to fully enable
1326 the SslBump feature.
1328 Omitting the mode flag causes default forward proxy mode to be used.
1331 Accelerator Mode Options:
1333 defaultsite=domainname
1334 What to use for the Host: header if it is not present
1335 in a request. Determines what site (not origin server)
1336 accelerators should consider the default.
1338 no-vhost Disable using HTTP/1.1 Host header for virtual domain support.
1340 protocol= Protocol to reconstruct accelerated requests with.
1341 Defaults to http for http_port and https for
1344 vport Virtual host port support. Using the http_port number
1345 instead of the port passed on Host: headers.
1347 vport=NN Virtual host port support. Using the specified port
1348 number instead of the port passed on Host: headers.
1351 Act as if this Squid is the origin server.
1352 This currently means generate new Date: and Expires:
1353 headers on HIT instead of adding Age:.
1355 ignore-cc Ignore request Cache-Control headers.
1357 WARNING: This option violates HTTP specifications if
1358 used in non-accelerator setups.
1360 allow-direct Allow direct forwarding in accelerator mode. Normally
1361 accelerated requests are denied direct forwarding as if
1362 never_direct was used.
1364 WARNING: this option opens accelerator mode to security
1365 vulnerabilities usually only affecting in interception
1366 mode. Make sure to protect forwarding with suitable
1367 http_access rules when using this.
1370 SSL Bump Mode Options:
1371 In addition to these options ssl-bump requires TLS/SSL options.
1373 generate-host-certificates[=<on|off>]
1374 Dynamically create SSL server certificates for the
1375 destination hosts of bumped CONNECT requests.When
1376 enabled, the cert and key options are used to sign
1377 generated certificates. Otherwise generated
1378 certificate will be selfsigned.
1379 If there is a CA certificate lifetime of the generated
1380 certificate equals lifetime of the CA certificate. If
1381 generated certificate is selfsigned lifetime is three
1383 This option is enabled by default when ssl-bump is used.
1384 See the ssl-bump option above for more information.
1386 dynamic_cert_mem_cache_size=SIZE
1387 Approximate total RAM size spent on cached generated
1388 certificates. If set to zero, caching is disabled. The
1389 default value is 4MB. An average XXX-bit certificate
1390 consumes about XXX bytes of RAM.
1394 cert= Path to SSL certificate (PEM format).
1396 key= Path to SSL private key file (PEM format)
1397 if not specified, the certificate file is
1398 assumed to be a combined certificate and
1401 version= The version of SSL/TLS supported
1402 1 automatic (default)
1407 cipher= Colon separated list of supported ciphers.
1408 NOTE: some ciphers such as EDH ciphers depend on
1409 additional settings. If those settings are
1410 omitted the ciphers may be silently ignored
1411 by the OpenSSL library.
1413 options= Various SSL implementation options. The most important
1415 NO_SSLv2 Disallow the use of SSLv2
1416 NO_SSLv3 Disallow the use of SSLv3
1417 NO_TLSv1 Disallow the use of TLSv1
1418 SINGLE_DH_USE Always create a new key when using
1419 temporary/ephemeral DH key exchanges
1420 ALL Enable various bug workarounds
1421 suggested as "harmless" by OpenSSL
1422 Be warned that this reduces SSL/TLS
1423 strength to some attacks.
1424 See OpenSSL SSL_CTX_set_options documentation for a
1425 complete list of options.
1427 clientca= File containing the list of CAs to use when
1428 requesting a client certificate.
1430 cafile= File containing additional CA certificates to
1431 use when verifying client certificates. If unset
1432 clientca will be used.
1434 capath= Directory containing additional CA certificates
1435 and CRL lists to use when verifying client certificates.
1437 crlfile= File of additional CRL lists to use when verifying
1438 the client certificate, in addition to CRLs stored in
1439 the capath. Implies VERIFY_CRL flag below.
1441 dhparams= File containing DH parameters for temporary/ephemeral
1442 DH key exchanges. See OpenSSL documentation for details
1443 on how to create this file.
1444 WARNING: EDH ciphers will be silently disabled if this
1447 sslflags= Various flags modifying the use of SSL:
1449 Don't request client certificates
1450 immediately, but wait until acl processing
1451 requires a certificate (not yet implemented).
1453 Don't use the default CA lists built in
1456 Don't allow for session reuse. Each connection
1457 will result in a new SSL session.
1459 Verify CRL lists when accepting client
1462 Verify CRL lists for all certificates in the
1463 client certificate chain.
1465 sslcontext= SSL session ID context identifier.
1469 connection-auth[=on|off]
1470 use connection-auth=off to tell Squid to prevent
1471 forwarding Microsoft connection oriented authentication
1472 (NTLM, Negotiate and Kerberos)
1474 disable-pmtu-discovery=
1475 Control Path-MTU discovery usage:
1476 off lets OS decide on what to do (default).
1477 transparent disable PMTU discovery when transparent
1479 always disable always PMTU discovery.
1481 In many setups of transparently intercepting proxies
1482 Path-MTU discovery can not work on traffic towards the
1483 clients. This is the case when the intercepting device
1484 does not fully track connections and fails to forward
1485 ICMP must fragment messages to the cache server. If you
1486 have such setup and experience that certain clients
1487 sporadically hang or never complete requests set
1488 disable-pmtu-discovery option to 'transparent'.
1490 name= Specifies a internal name for the port. Defaults to
1491 the port specification (port or addr:port)
1493 tcpkeepalive[=idle,interval,timeout]
1494 Enable TCP keepalive probes of idle connections.
1495 In seconds; idle is the initial time before TCP starts
1496 probing the connection, interval how often to probe, and
1497 timeout the time before giving up.
1499 If you run Squid on a dual-homed machine with an internal
1500 and an external interface we recommend you to specify the
1501 internal address:port in http_port. This way Squid will only be
1502 visible on the internal address.
1506 # Squid normally listens to port 3128
1507 http_port @DEFAULT_HTTP_PORT@
1513 TYPE: https_port_list
1515 LOC: Config.Sockaddr.https
1517 Usage: [ip:]port cert=certificate.pem [key=key.pem] [mode] [options...]
1519 The socket address where Squid will listen for client requests made
1520 over TLS or SSL connections. Commonly referred to as HTTPS.
1522 This is most useful for situations where you are running squid in
1523 accelerator mode and you want to do the SSL work at the accelerator level.
1525 You may specify multiple socket addresses on multiple lines,
1526 each with their own SSL certificate and/or options.
1528 See http_port for a list of available options.
1531 NAME: tcp_outgoing_tos tcp_outgoing_ds tcp_outgoing_dscp
1534 LOC: Ip::Qos::TheConfig.tosToServer
1536 Allows you to select a TOS/Diffserv value for packets outgoing
1537 on the server side, based on an ACL.
1539 tcp_outgoing_tos ds-field [!]aclname ...
1541 Example where normal_service_net uses the TOS value 0x00
1542 and good_service_net uses 0x20
1544 acl normal_service_net src 10.0.0.0/24
1545 acl good_service_net src 10.0.1.0/24
1546 tcp_outgoing_tos 0x00 normal_service_net
1547 tcp_outgoing_tos 0x20 good_service_net
1549 TOS/DSCP values really only have local significance - so you should
1550 know what you're specifying. For more information, see RFC2474,
1551 RFC2475, and RFC3260.
1553 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
1554 "default" to use whatever default your host has. Note that in
1555 practice often only multiples of 4 is usable as the two rightmost bits
1556 have been redefined for use by ECN (RFC 3168 section 23.1).
1558 Processing proceeds in the order specified, and stops at first fully
1562 NAME: clientside_tos
1565 LOC: Ip::Qos::TheConfig.tosToClient
1567 Allows you to select a TOS/Diffserv value for packets being transmitted
1568 on the client-side, based on an ACL.
1570 clientside_tos ds-field [!]aclname ...
1572 Example where normal_service_net uses the TOS value 0x00
1573 and good_service_net uses 0x20
1575 acl normal_service_net src 10.0.0.0/24
1576 acl good_service_net src 10.0.1.0/24
1577 clientside_tos 0x00 normal_service_net
1578 clientside_tos 0x20 good_service_net
1580 Note: This feature is incompatible with qos_flows. Any TOS values set here
1581 will be overwritten by TOS values in qos_flows.
1584 NAME: tcp_outgoing_mark
1586 IFDEF: SO_MARK&&USE_LIBCAP
1588 LOC: Ip::Qos::TheConfig.nfmarkToServer
1590 Allows you to apply a Netfilter mark value to outgoing packets
1591 on the server side, based on an ACL.
1593 tcp_outgoing_mark mark-value [!]aclname ...
1595 Example where normal_service_net uses the mark value 0x00
1596 and good_service_net uses 0x20
1598 acl normal_service_net src 10.0.0.0/24
1599 acl good_service_net src 10.0.1.0/24
1600 tcp_outgoing_mark 0x00 normal_service_net
1601 tcp_outgoing_mark 0x20 good_service_net
1604 NAME: clientside_mark
1606 IFDEF: SO_MARK&&USE_LIBCAP
1608 LOC: Ip::Qos::TheConfig.nfmarkToClient
1610 Allows you to apply a Netfilter mark value to packets being transmitted
1611 on the client-side, based on an ACL.
1613 clientside_mark mark-value [!]aclname ...
1615 Example where normal_service_net uses the mark value 0x00
1616 and good_service_net uses 0x20
1618 acl normal_service_net src 10.0.0.0/24
1619 acl good_service_net src 10.0.1.0/24
1620 clientside_mark 0x00 normal_service_net
1621 clientside_mark 0x20 good_service_net
1623 Note: This feature is incompatible with qos_flows. Any mark values set here
1624 will be overwritten by mark values in qos_flows.
1631 LOC: Ip::Qos::TheConfig
1633 Allows you to select a TOS/DSCP value to mark outgoing
1634 connections with, based on where the reply was sourced. For
1635 platforms using netfilter, allows you to set a netfilter mark
1636 value instead of, or in addition to, a TOS value.
1638 TOS values really only have local significance - so you should
1639 know what you're specifying. For more information, see RFC2474,
1640 RFC2475, and RFC3260.
1642 The TOS/DSCP byte must be exactly that - a octet value 0 - 255. Note that
1643 in practice often only multiples of 4 is usable as the two rightmost bits
1644 have been redefined for use by ECN (RFC 3168 section 23.1).
1646 Mark values can be any unsigned 32-bit integer value.
1648 This setting is configured by setting the following values:
1650 tos|mark Whether to set TOS or netfilter mark values
1652 local-hit=0xFF Value to mark local cache hits.
1654 sibling-hit=0xFF Value to mark hits from sibling peers.
1656 parent-hit=0xFF Value to mark hits from parent peers.
1658 miss=0xFF[/mask] Value to mark cache misses. Takes precedence
1659 over the preserve-miss feature (see below), unless
1660 mask is specified, in which case only the bits
1661 specified in the mask are written.
1663 The TOS variant of the following features are only possible on Linux
1664 and require your kernel to be patched with the TOS preserving ZPH
1665 patch, available from http://zph.bratcheda.org
1666 No patch is needed to preserve the netfilter mark, which will work
1667 with all variants of netfilter.
1669 disable-preserve-miss
1670 This option disables the preservation of the TOS or netfilter
1671 mark. By default, the existing TOS or netfilter mark value of
1672 the response coming from the remote server will be retained
1673 and masked with miss-mark.
1674 NOTE: in the case of a netfilter mark, the mark must be set on
1675 the connection (using the CONNMARK target) not on the packet
1679 Allows you to mask certain bits in the TOS or mark value
1680 received from the remote server, before copying the value to
1681 the TOS sent towards clients.
1682 Default for tos: 0xFF (TOS from server is not changed).
1683 Default for mark: 0xFFFFFFFF (mark from server is not changed).
1685 All of these features require the --enable-zph-qos compilation flag
1686 (enabled by default). Netfilter marking also requires the
1687 libnetfilter_conntrack libraries (--with-netfilter-conntrack) and
1688 libcap 2.09+ (--with-libcap).
1692 NAME: tcp_outgoing_address
1695 LOC: Config.accessList.outgoing_address
1697 Allows you to map requests to different outgoing IP addresses
1698 based on the username or source address of the user making
1701 tcp_outgoing_address ipaddr [[!]aclname] ...
1704 Forwarding clients with dedicated IPs for certain subnets.
1706 acl normal_service_net src 10.0.0.0/24
1707 acl good_service_net src 10.0.2.0/24
1709 tcp_outgoing_address 2001:db8::c001 good_service_net
1710 tcp_outgoing_address 10.1.0.2 good_service_net
1712 tcp_outgoing_address 2001:db8::beef normal_service_net
1713 tcp_outgoing_address 10.1.0.1 normal_service_net
1715 tcp_outgoing_address 2001:db8::1
1716 tcp_outgoing_address 10.1.0.3
1718 Processing proceeds in the order specified, and stops at first fully
1721 Squid will add an implicit IP version test to each line.
1722 Requests going to IPv4 websites will use the outgoing 10.1.0.* addresses.
1723 Requests going to IPv6 websites will use the outgoing 2001:db8:* addresses.
1726 NOTE: The use of this directive using client dependent ACLs is
1727 incompatible with the use of server side persistent connections. To
1728 ensure correct results it is best to set server_persistent_connections
1729 to off when using this directive in such configurations.
1731 NOTE: The use of this directive to set a local IP on outgoing TCP links
1732 is incompatible with using TPROXY to set client IP out outbound TCP links.
1733 When needing to contact peers use the no-tproxy cache_peer option and the
1734 client_dst_passthru directive re-enable normal forwarding such as this.
1738 NAME: host_verify_strict
1741 LOC: Config.onoff.hostStrictVerify
1743 Regardless of this option setting, when dealing with intercepted
1744 traffic, Squid always verifies that the destination IP address matches
1745 the Host header domain or IP (called 'authority form URL').
1747 This enforcement is performed to satisfy a MUST-level requirement in
1748 RFC 2616 section 14.23: "The Host field value MUST represent the naming
1749 authority of the origin server or gateway given by the original URL".
1752 Squid always responds with an HTTP 409 (Conflict) error
1753 page and logs a security warning if there is no match.
1755 Squid verifies that the destination IP address matches
1756 the Host header for forward-proxy and reverse-proxy traffic
1757 as well. For those traffic types, Squid also enables the
1758 following checks, comparing the corresponding Host header
1759 and Request-URI components:
1761 * The host names (domain or IP) must be identical,
1762 but valueless or missing Host header disables all checks.
1763 For the two host names to match, both must be either IP
1766 * Port numbers must be identical, but if a port is missing
1767 the scheme-default port is assumed.
1770 When set to OFF (the default):
1771 Squid allows suspicious requests to continue but logs a
1772 security warning and blocks caching of the response.
1774 * Forward-proxy traffic is not checked at all.
1776 * Reverse-proxy traffic is not checked at all.
1778 * Intercepted traffic which passes verification is handled
1781 For now it also forces suspicious requests to go DIRECT to the
1782 original destination, overriding client_dst_passthru for
1783 intercepted requests which fail Host: verification.
1785 For now suspicious intercepted CONNECT requests are always
1786 responded to with an HTTP 409 (Conflict) error page.
1789 NAME: client_dst_passthru
1792 LOC: Config.onoff.client_dst_passthru
1794 With NAT or TPROXY intercepted traffic Squid may pass the request
1795 directly to the original client destination IP or seek a faster
1798 This option (on by default) prevents cache_peer and alternative DNS
1799 entries being used on intercepted traffic. Both of which lead to
1800 the security vulnerability outlined below.
1804 This directive should only be disabled if cache_peer are required.
1806 As described in CVE-2009-0801 when the Host: header alone is used
1807 to determine the destination of a request it becomes trivial for
1808 malicious scripts on remote websites to bypass browser same-origin
1809 security policy and sandboxing protections.
1811 The cause of this is that such applets are allowed to perform their
1812 own HTTP stack, in which case the same-origin policy of the browser
1813 sandbox only verifies that the applet tries to contact the same IP
1814 as from where it was loaded at the IP level. The Host: header may
1815 be different from the connected IP and approved origin.
1821 -----------------------------------------------------------------------------
1824 NAME: ssl_unclean_shutdown
1828 LOC: Config.SSL.unclean_shutdown
1830 Some browsers (especially MSIE) bugs out on SSL shutdown
1837 LOC: Config.SSL.ssl_engine
1840 The OpenSSL engine to use. You will need to set this if you
1841 would like to use hardware SSL acceleration for example.
1844 NAME: sslproxy_client_certificate
1847 LOC: Config.ssl_client.cert
1850 Client SSL Certificate to use when proxying https:// URLs
1853 NAME: sslproxy_client_key
1856 LOC: Config.ssl_client.key
1859 Client SSL Key to use when proxying https:// URLs
1862 NAME: sslproxy_version
1865 LOC: Config.ssl_client.version
1868 SSL version level to use when proxying https:// URLs
1871 NAME: sslproxy_options
1874 LOC: Config.ssl_client.options
1877 SSL implementation options to use when proxying https:// URLs
1879 The most important being:
1881 NO_SSLv2 Disallow the use of SSLv2
1882 NO_SSLv3 Disallow the use of SSLv3
1883 NO_TLSv1 Disallow the use of TLSv1
1885 Always create a new key when using temporary/ephemeral
1888 Disable use of RFC5077 session tickets. Some servers
1889 may have problems understanding the TLS extension due
1890 to ambiguous specification in RFC4507.
1891 ALL Enable various bug workarounds suggested as "harmless"
1892 by OpenSSL. Be warned that this may reduce SSL/TLS
1893 strength to some attacks.
1895 See the OpenSSL SSL_CTX_set_options documentation for a
1896 complete list of possible options.
1899 NAME: sslproxy_cipher
1902 LOC: Config.ssl_client.cipher
1905 SSL cipher list to use when proxying https:// URLs
1907 Colon separated list of supported ciphers.
1910 NAME: sslproxy_cafile
1913 LOC: Config.ssl_client.cafile
1916 file containing CA certificates to use when verifying server
1917 certificates while proxying https:// URLs
1920 NAME: sslproxy_capath
1923 LOC: Config.ssl_client.capath
1926 directory containing CA certificates to use when verifying
1927 server certificates while proxying https:// URLs
1933 LOC: Config.accessList.ssl_bump
1936 This ACL controls which CONNECT requests to an http_port
1937 marked with an sslBump flag are actually "bumped". Please
1938 see the sslBump flag of an http_port option for more details
1939 about decoding proxied SSL connections.
1941 By default, no requests are bumped.
1943 See also: http_port ssl-bump
1945 This clause supports both fast and slow acl types.
1946 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1949 # Example: Bump all requests except those originating from localhost and
1950 # those going to webax.com or example.com sites.
1952 acl localhost src 127.0.0.1/32
1953 acl broken_sites dstdomain .webax.com
1954 acl broken_sites dstdomain .example.com
1955 ssl_bump deny localhost
1956 ssl_bump deny broken_sites
1960 NAME: sslproxy_flags
1963 LOC: Config.ssl_client.flags
1966 Various flags modifying the use of SSL while proxying https:// URLs:
1967 DONT_VERIFY_PEER Accept certificates that fail verification.
1968 For refined control, see sslproxy_cert_error.
1969 NO_DEFAULT_CA Don't use the default CA list built in
1973 NAME: sslproxy_cert_error
1976 LOC: Config.ssl_client.cert_error
1979 Use this ACL to bypass server certificate validation errors.
1981 For example, the following lines will bypass all validation errors
1982 when talking to servers located at 172.16.0.0/16. All other
1983 validation errors will result in ERR_SECURE_CONNECT_FAIL error.
1985 acl BrokenServersAtTrustedIP dst 172.16.0.0/16
1986 sslproxy_cert_error allow BrokenServersAtTrustedIP
1987 sslproxy_cert_error deny all
1989 This clause only supports fast acl types.
1990 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1991 Using slow acl types may result in server crashes
1993 Without this option, all server certificate validation errors
1994 terminate the transaction. Bypassing validation errors is dangerous
1995 because an error usually implies that the server cannot be trusted and
1996 the connection may be insecure.
1998 See also: sslproxy_flags and DONT_VERIFY_PEER.
2000 Default setting: sslproxy_cert_error deny all
2003 NAME: sslpassword_program
2006 LOC: Config.Program.ssl_password
2009 Specify a program used for entering SSL key passphrases
2010 when using encrypted SSL certificate keys. If not specified
2011 keys must either be unencrypted, or Squid started with the -N
2012 option to allow it to query interactively for the passphrase.
2014 The key file name is given as argument to the program allowing
2015 selection of the right password if you have multiple encrypted
2020 OPTIONS RELATING TO EXTERNAL SSL_CRTD
2021 -----------------------------------------------------------------------------
2024 NAME: sslcrtd_program
2027 DEFAULT: @DEFAULT_SSL_CRTD@ -s @DEFAULT_SSL_DB_DIR@ -M 4MB
2028 LOC: Ssl::TheConfig.ssl_crtd
2030 Specify the location and options of the executable for ssl_crtd process.
2031 @DEFAULT_SSL_CRTD@ program requires -s and -M parameters
2032 For more information use:
2033 @DEFAULT_SSL_CRTD@ -h
2036 NAME: sslcrtd_children
2037 TYPE: HelperChildConfig
2039 DEFAULT: 32 startup=5 idle=1
2040 LOC: Ssl::TheConfig.ssl_crtdChildren
2042 The maximum number of processes spawn to service ssl server.
2043 The maximum this may be safely set to is 32.
2045 The startup= and idle= options allow some measure of skew in your
2050 Sets the minimum number of processes to spawn when Squid
2051 starts or reconfigures. When set to zero the first request will
2052 cause spawning of the first child process to handle it.
2054 Starting too few children temporary slows Squid under load while it
2055 tries to spawn enough additional processes to cope with traffic.
2059 Sets a minimum of how many processes Squid is to try and keep available
2060 at all times. When traffic begins to rise above what the existing
2061 processes can handle this many more will be spawned up to the maximum
2062 configured. A minimum setting of 1 is required.
2064 You must have at least one ssl_crtd process.
2068 OPTIONS WHICH AFFECT THE NEIGHBOR SELECTION ALGORITHM
2069 -----------------------------------------------------------------------------
2077 To specify other caches in a hierarchy, use the format:
2079 cache_peer hostname type http-port icp-port [options]
2084 # hostname type port port options
2085 # -------------------- -------- ----- ----- -----------
2086 cache_peer parent.foo.net parent 3128 3130 default
2087 cache_peer sib1.foo.net sibling 3128 3130 proxy-only
2088 cache_peer sib2.foo.net sibling 3128 3130 proxy-only
2089 cache_peer example.com parent 80 0 default
2090 cache_peer cdn.example.com sibling 3128 0
2092 type: either 'parent', 'sibling', or 'multicast'.
2094 proxy-port: The port number where the peer accept HTTP requests.
2095 For other Squid proxies this is usually 3128
2096 For web servers this is usually 80
2098 icp-port: Used for querying neighbor caches about objects.
2099 Set to 0 if the peer does not support ICP or HTCP.
2100 See ICP and HTCP options below for additional details.
2103 ==== ICP OPTIONS ====
2105 You MUST also set icp_port and icp_access explicitly when using these options.
2106 The defaults will prevent peer traffic using ICP.
2109 no-query Disable ICP queries to this neighbor.
2112 Indicates the named peer is a member of a multicast group.
2113 ICP queries will not be sent directly to the peer, but ICP
2114 replies will be accepted from it.
2116 closest-only Indicates that, for ICP_OP_MISS replies, we'll only forward
2117 CLOSEST_PARENT_MISSes and never FIRST_PARENT_MISSes.
2120 To only send ICP queries to this neighbor infrequently.
2121 This is used to keep the neighbor round trip time updated
2122 and is usually used in conjunction with weighted-round-robin.
2125 ==== HTCP OPTIONS ====
2127 You MUST also set htcp_port and htcp_access explicitly when using these options.
2128 The defaults will prevent peer traffic using HTCP.
2131 htcp Send HTCP, instead of ICP, queries to the neighbor.
2132 You probably also want to set the "icp-port" to 4827
2133 instead of 3130. This directive accepts a comma separated
2134 list of options described below.
2136 htcp=oldsquid Send HTCP to old Squid versions (2.5 or earlier).
2138 htcp=no-clr Send HTCP to the neighbor but without
2139 sending any CLR requests. This cannot be used with
2142 htcp=only-clr Send HTCP to the neighbor but ONLY CLR requests.
2143 This cannot be used with no-clr.
2146 Send HTCP to the neighbor including CLRs but only when
2147 they do not result from PURGE requests.
2150 Forward any HTCP CLR requests this proxy receives to the peer.
2153 ==== PEER SELECTION METHODS ====
2155 The default peer selection method is ICP, with the first responding peer
2156 being used as source. These options can be used for better load balancing.
2159 default This is a parent cache which can be used as a "last-resort"
2160 if a peer cannot be located by any of the peer-selection methods.
2161 If specified more than once, only the first is used.
2163 round-robin Load-Balance parents which should be used in a round-robin
2164 fashion in the absence of any ICP queries.
2165 weight=N can be used to add bias.
2167 weighted-round-robin
2168 Load-Balance parents which should be used in a round-robin
2169 fashion with the frequency of each parent being based on the
2170 round trip time. Closer parents are used more often.
2171 Usually used for background-ping parents.
2172 weight=N can be used to add bias.
2174 carp Load-Balance parents which should be used as a CARP array.
2175 The requests will be distributed among the parents based on the
2176 CARP load balancing hash function based on their weight.
2178 userhash Load-balance parents based on the client proxy_auth or ident username.
2180 sourcehash Load-balance parents based on the client source IP.
2183 To be used only for cache peers of type "multicast".
2184 ALL members of this multicast group have "sibling"
2185 relationship with it, not "parent". This is to a multicast
2186 group when the requested object would be fetched only from
2187 a "parent" cache, anyway. It's useful, e.g., when
2188 configuring a pool of redundant Squid proxies, being
2189 members of the same multicast group.
2192 ==== PEER SELECTION OPTIONS ====
2194 weight=N use to affect the selection of a peer during any weighted
2195 peer-selection mechanisms.
2196 The weight must be an integer; default is 1,
2197 larger weights are favored more.
2198 This option does not affect parent selection if a peering
2199 protocol is not in use.
2201 basetime=N Specify a base amount to be subtracted from round trip
2203 It is subtracted before division by weight in calculating
2204 which parent to fectch from. If the rtt is less than the
2205 base time the rtt is set to a minimal value.
2207 ttl=N Specify a TTL to use when sending multicast ICP queries
2209 Only useful when sending to a multicast group.
2210 Because we don't accept ICP replies from random
2211 hosts, you must configure other group members as
2212 peers with the 'multicast-responder' option.
2214 no-delay To prevent access to this neighbor from influencing the
2217 digest-url=URL Tell Squid to fetch the cache digest (if digests are
2218 enabled) for this host from the specified URL rather
2219 than the Squid default location.
2222 ==== CARP OPTIONS ====
2224 carp-key=key-specification
2225 use a different key than the full URL to hash against the peer.
2226 the key-specification is a comma-separated list of the keywords
2227 scheme, host, port, path, params
2228 Order is not important.
2230 ==== ACCELERATOR / REVERSE-PROXY OPTIONS ====
2232 originserver Causes this parent to be contacted as an origin server.
2233 Meant to be used in accelerator setups when the peer
2237 Set the Host header of requests forwarded to this peer.
2238 Useful in accelerator setups where the server (peer)
2239 expects a certain domain name but clients may request
2240 others. ie example.com or www.example.com
2242 no-digest Disable request of cache digests.
2245 Disables requesting ICMP RTT database (NetDB).
2248 ==== AUTHENTICATION OPTIONS ====
2251 If this is a personal/workgroup proxy and your parent
2252 requires proxy authentication.
2254 Note: The string can include URL escapes (i.e. %20 for
2255 spaces). This also means % must be written as %%.
2258 Send login details received from client to this peer.
2259 Both Proxy- and WWW-Authorization headers are passed
2260 without alteration to the peer.
2261 Authentication is not required by Squid for this to work.
2263 Note: This will pass any form of authentication but
2264 only Basic auth will work through a proxy unless the
2265 connection-auth options are also used.
2267 login=PASS Send login details received from client to this peer.
2268 Authentication is not required by this option.
2270 If there are no client-provided authentication headers
2271 to pass on, but username and password are available
2272 from an external ACL user= and password= result tags
2273 they may be sent instead.
2275 Note: To combine this with proxy_auth both proxies must
2276 share the same user database as HTTP only allows for
2277 a single login (one for proxy, one for origin server).
2278 Also be warned this will expose your users proxy
2279 password to the peer. USE WITH CAUTION
2282 Send the username to the upstream cache, but with a
2283 fixed password. This is meant to be used when the peer
2284 is in another administrative domain, but it is still
2285 needed to identify each user.
2286 The star can optionally be followed by some extra
2287 information which is added to the username. This can
2288 be used to identify this proxy to the peer, similar to
2289 the login=username:password option above.
2292 If this is a personal/workgroup proxy and your parent
2293 requires a secure proxy authentication.
2294 The first principal from the default keytab or defined by
2295 the environment variable KRB5_KTNAME will be used.
2297 WARNING: The connection may transmit requests from multiple
2298 clients. Negotiate often assumes end-to-end authentication
2299 and a single-client. Which is not strictly true here.
2301 login=NEGOTIATE:principal_name
2302 If this is a personal/workgroup proxy and your parent
2303 requires a secure proxy authentication.
2304 The principal principal_name from the default keytab or
2305 defined by the environment variable KRB5_KTNAME will be
2308 WARNING: The connection may transmit requests from multiple
2309 clients. Negotiate often assumes end-to-end authentication
2310 and a single-client. Which is not strictly true here.
2312 connection-auth=on|off
2313 Tell Squid that this peer does or not support Microsoft
2314 connection oriented authentication, and any such
2315 challenges received from there should be ignored.
2316 Default is auto to automatically determine the status
2320 ==== SSL / HTTPS / TLS OPTIONS ====
2322 ssl Encrypt connections to this peer with SSL/TLS.
2324 sslcert=/path/to/ssl/certificate
2325 A client SSL certificate to use when connecting to
2328 sslkey=/path/to/ssl/key
2329 The private SSL key corresponding to sslcert above.
2330 If 'sslkey' is not specified 'sslcert' is assumed to
2331 reference a combined file containing both the
2332 certificate and the key.
2335 The SSL version to use when connecting to this peer
2336 1 = automatic (default)
2341 sslcipher=... The list of valid SSL ciphers to use when connecting
2344 ssloptions=... Specify various SSL implementation options:
2346 NO_SSLv2 Disallow the use of SSLv2
2347 NO_SSLv3 Disallow the use of SSLv3
2348 NO_TLSv1 Disallow the use of TLSv1
2350 Always create a new key when using
2351 temporary/ephemeral DH key exchanges
2352 ALL Enable various bug workarounds
2353 suggested as "harmless" by OpenSSL
2354 Be warned that this reduces SSL/TLS
2355 strength to some attacks.
2357 See the OpenSSL SSL_CTX_set_options documentation for a
2360 sslcafile=... A file containing additional CA certificates to use
2361 when verifying the peer certificate.
2363 sslcapath=... A directory containing additional CA certificates to
2364 use when verifying the peer certificate.
2366 sslcrlfile=... A certificate revocation list file to use when
2367 verifying the peer certificate.
2369 sslflags=... Specify various flags modifying the SSL implementation:
2372 Accept certificates even if they fail to
2375 Don't use the default CA list built in
2378 Don't verify the peer certificate
2379 matches the server name
2381 ssldomain= The peer name as advertised in it's certificate.
2382 Used for verifying the correctness of the received peer
2383 certificate. If not specified the peer hostname will be
2387 Enable the "Front-End-Https: On" header needed when
2388 using Squid as a SSL frontend in front of Microsoft OWA.
2389 See MS KB document Q307347 for details on this header.
2390 If set to auto the header will only be added if the
2391 request is forwarded as a https:// URL.
2394 ==== GENERAL OPTIONS ====
2397 A peer-specific connect timeout.
2398 Also see the peer_connect_timeout directive.
2400 connect-fail-limit=N
2401 How many times connecting to a peer must fail before
2402 it is marked as down. Default is 10.
2404 allow-miss Disable Squid's use of only-if-cached when forwarding
2405 requests to siblings. This is primarily useful when
2406 icp_hit_stale is used by the sibling. To extensive use
2407 of this option may result in forwarding loops, and you
2408 should avoid having two-way peerings with this option.
2409 For example to deny peer usage on requests from peer
2410 by denying cache_peer_access if the source is a peer.
2412 max-conn=N Limit the amount of connections Squid may open to this
2415 name=xxx Unique name for the peer.
2416 Required if you have multiple peers on the same host
2417 but different ports.
2418 This name can be used in cache_peer_access and similar
2419 directives to dentify the peer.
2420 Can be used by outgoing access controls through the
2423 no-tproxy Do not use the client-spoof TPROXY support when forwarding
2424 requests to this peer. Use normal address selection instead.
2426 proxy-only objects fetched from the peer will not be stored locally.
2430 NAME: cache_peer_domain cache_host_domain
2435 Use to limit the domains for which a neighbor cache will be
2438 cache_peer_domain cache-host domain [domain ...]
2439 cache_peer_domain cache-host !domain
2441 For example, specifying
2443 cache_peer_domain parent.foo.net .edu
2445 has the effect such that UDP query packets are sent to
2446 'bigserver' only when the requested object exists on a
2447 server in the .edu domain. Prefixing the domainname
2448 with '!' means the cache will be queried for objects
2451 NOTE: * Any number of domains may be given for a cache-host,
2452 either on the same or separate lines.
2453 * When multiple domains are given for a particular
2454 cache-host, the first matched domain is applied.
2455 * Cache hosts with no domain restrictions are queried
2457 * There are no defaults.
2458 * There is also a 'cache_peer_access' tag in the ACL
2462 NAME: cache_peer_access
2467 Similar to 'cache_peer_domain' but provides more flexibility by
2470 cache_peer_access cache-host allow|deny [!]aclname ...
2472 The syntax is identical to 'http_access' and the other lists of
2473 ACL elements. See the comments for 'http_access' below, or
2474 the Squid FAQ (http://wiki.squid-cache.org/SquidFaq/SquidAcl).
2477 NAME: neighbor_type_domain
2478 TYPE: hostdomaintype
2482 usage: neighbor_type_domain neighbor parent|sibling domain domain ...
2484 Modifying the neighbor type for specific domains is now
2485 possible. You can treat some domains differently than the
2486 default neighbor type specified on the 'cache_peer' line.
2487 Normally it should only be necessary to list domains which
2488 should be treated differently because the default neighbor type
2489 applies for hostnames which do not match domains listed here.
2492 cache_peer cache.foo.org parent 3128 3130
2493 neighbor_type_domain cache.foo.org sibling .com .net
2494 neighbor_type_domain cache.foo.org sibling .au .de
2497 NAME: dead_peer_timeout
2501 LOC: Config.Timeout.deadPeer
2503 This controls how long Squid waits to declare a peer cache
2504 as "dead." If there are no ICP replies received in this
2505 amount of time, Squid will declare the peer dead and not
2506 expect to receive any further ICP replies. However, it
2507 continues to send ICP queries, and will mark the peer as
2508 alive upon receipt of the first subsequent ICP reply.
2510 This timeout also affects when Squid expects to receive ICP
2511 replies from peers. If more than 'dead_peer' seconds have
2512 passed since the last ICP reply was received, Squid will not
2513 expect to receive an ICP reply on the next query. Thus, if
2514 your time between requests is greater than this timeout, you
2515 will see a lot of requests sent DIRECT to origin servers
2516 instead of to your parents.
2519 NAME: forward_max_tries
2522 LOC: Config.forward_max_tries
2524 Controls how many different forward paths Squid will try
2525 before giving up. See also forward_timeout.
2527 NOTE: connect_retries (default: none) can make each of these
2528 possible forwarding paths be tried multiple times.
2531 NAME: hierarchy_stoplist
2534 LOC: Config.hierarchy_stoplist
2536 A list of words which, if found in a URL, cause the object to
2537 be handled directly by this cache. In other words, use this
2538 to not query neighbor caches for certain objects. You may
2539 list this option multiple times.
2542 hierarchy_stoplist cgi-bin ?
2544 Note: never_direct overrides this option.
2548 MEMORY CACHE OPTIONS
2549 -----------------------------------------------------------------------------
2556 LOC: Config.memMaxSize
2558 NOTE: THIS PARAMETER DOES NOT SPECIFY THE MAXIMUM PROCESS SIZE.
2559 IT ONLY PLACES A LIMIT ON HOW MUCH ADDITIONAL MEMORY SQUID WILL
2560 USE AS A MEMORY CACHE OF OBJECTS. SQUID USES MEMORY FOR OTHER
2561 THINGS AS WELL. SEE THE SQUID FAQ SECTION 8 FOR DETAILS.
2563 'cache_mem' specifies the ideal amount of memory to be used
2565 * In-Transit objects
2567 * Negative-Cached objects
2569 Data for these objects are stored in 4 KB blocks. This
2570 parameter specifies the ideal upper limit on the total size of
2571 4 KB blocks allocated. In-Transit objects take the highest
2574 In-transit objects have priority over the others. When
2575 additional space is needed for incoming data, negative-cached
2576 and hot objects will be released. In other words, the
2577 negative-cached and hot objects will fill up any unused space
2578 not needed for in-transit objects.
2580 If circumstances require, this limit will be exceeded.
2581 Specifically, if your incoming request rate requires more than
2582 'cache_mem' of memory to hold in-transit objects, Squid will
2583 exceed this limit to satisfy the new requests. When the load
2584 decreases, blocks will be freed until the high-water mark is
2585 reached. Thereafter, blocks will be used to store hot
2588 If shared memory caching is enabled, Squid does not use the shared
2589 cache space for in-transit objects, but they still consume as much
2590 local memory as they need. For more details about the shared memory
2591 cache, see memory_cache_shared.
2594 NAME: maximum_object_size_in_memory
2598 LOC: Config.Store.maxInMemObjSize
2600 Objects greater than this size will not be attempted to kept in
2601 the memory cache. This should be set high enough to keep objects
2602 accessed frequently in memory to improve performance whilst low
2603 enough to keep larger objects from hoarding cache_mem.
2606 NAME: memory_cache_shared
2609 LOC: Config.memShared
2611 DEFAULT_DOC: "on" where supported if doing memory caching with multiple SMP workers.
2613 Controls whether the memory cache is shared among SMP workers.
2615 The shared memory cache is meant to occupy cache_mem bytes and replace
2616 the non-shared memory cache, although some entities may still be
2617 cached locally by workers for now (e.g., internal and in-transit
2618 objects may be served from a local memory cache even if shared memory
2619 caching is enabled).
2621 By default, the memory cache is shared if and only if all of the
2622 following conditions are satisfied: Squid runs in SMP mode with
2623 multiple workers, cache_mem is positive, and Squid environment
2624 supports required IPC primitives (e.g., POSIX shared memory segments
2625 and GCC-style atomic operations).
2627 To avoid blocking locks, shared memory uses opportunistic algorithms
2628 that do not guarantee that every cachable entity that could have been
2629 shared among SMP workers will actually be shared.
2631 Currently, entities exceeding 32KB in size cannot be shared.
2634 NAME: memory_cache_mode
2639 Controls which objects to keep in the memory cache (cache_mem)
2641 always Keep most recently fetched objects in memory (default)
2643 disk Only disk cache hits are kept in memory, which means
2644 an object must first be cached on disk and then hit
2645 a second time before cached in memory.
2647 network Only objects fetched from network is kept in memory
2650 NAME: memory_replacement_policy
2652 LOC: Config.memPolicy
2655 The memory replacement policy parameter determines which
2656 objects are purged from memory when memory space is needed.
2658 See cache_replacement_policy for details.
2663 -----------------------------------------------------------------------------
2666 NAME: cache_replacement_policy
2668 LOC: Config.replPolicy
2671 The cache replacement policy parameter determines which
2672 objects are evicted (replaced) when disk space is needed.
2674 lru : Squid's original list based LRU policy
2675 heap GDSF : Greedy-Dual Size Frequency
2676 heap LFUDA: Least Frequently Used with Dynamic Aging
2677 heap LRU : LRU policy implemented using a heap
2679 Applies to any cache_dir lines listed below this.
2681 The LRU policies keeps recently referenced objects.
2683 The heap GDSF policy optimizes object hit rate by keeping smaller
2684 popular objects in cache so it has a better chance of getting a
2685 hit. It achieves a lower byte hit rate than LFUDA though since
2686 it evicts larger (possibly popular) objects.
2688 The heap LFUDA policy keeps popular objects in cache regardless of
2689 their size and thus optimizes byte hit rate at the expense of
2690 hit rate since one large, popular object will prevent many
2691 smaller, slightly less popular objects from being cached.
2693 Both policies utilize a dynamic aging mechanism that prevents
2694 cache pollution that can otherwise occur with frequency-based
2695 replacement policies.
2697 NOTE: if using the LFUDA replacement policy you should increase
2698 the value of maximum_object_size above its default of 4096 KB to
2699 to maximize the potential byte hit rate improvement of LFUDA.
2701 For more information about the GDSF and LFUDA cache replacement
2702 policies see http://www.hpl.hp.com/techreports/1999/HPL-1999-69.html
2703 and http://fog.hpl.external.hp.com/techreports/98/HPL-98-173.html.
2709 LOC: Config.cacheSwap
2713 cache_dir Type Directory-Name Fs-specific-data [options]
2715 You can specify multiple cache_dir lines to spread the
2716 cache among different disk partitions.
2718 Type specifies the kind of storage system to use. Only "ufs"
2719 is built by default. To enable any of the other storage systems
2720 see the --enable-storeio configure option.
2722 'Directory' is a top-level directory where cache swap
2723 files will be stored. If you want to use an entire disk
2724 for caching, this can be the mount-point directory.
2725 The directory must exist and be writable by the Squid
2726 process. Squid will NOT create this directory for you.
2728 In SMP configurations, cache_dir must not precede the workers option
2729 and should use configuration macros or conditionals to give each
2730 worker interested in disk caching a dedicated cache directory.
2734 "ufs" is the old well-known Squid storage format that has always
2737 cache_dir ufs Directory-Name Mbytes L1 L2 [options]
2739 'Mbytes' is the amount of disk space (MB) to use under this
2740 directory. The default is 100 MB. Change this to suit your
2741 configuration. Do NOT put the size of your disk drive here.
2742 Instead, if you want Squid to use the entire disk drive,
2743 subtract 20% and use that value.
2745 'L1' is the number of first-level subdirectories which
2746 will be created under the 'Directory'. The default is 16.
2748 'L2' is the number of second-level subdirectories which
2749 will be created under each first-level directory. The default
2752 The aufs store type:
2754 "aufs" uses the same storage format as "ufs", utilizing
2755 POSIX-threads to avoid blocking the main Squid process on
2756 disk-I/O. This was formerly known in Squid as async-io.
2758 cache_dir aufs Directory-Name Mbytes L1 L2 [options]
2760 see argument descriptions under ufs above
2762 The diskd store type:
2764 "diskd" uses the same storage format as "ufs", utilizing a
2765 separate process to avoid blocking the main Squid process on
2768 cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n]
2770 see argument descriptions under ufs above
2772 Q1 specifies the number of unacknowledged I/O requests when Squid
2773 stops opening new files. If this many messages are in the queues,
2774 Squid won't open new files. Default is 64
2776 Q2 specifies the number of unacknowledged messages when Squid
2777 starts blocking. If this many messages are in the queues,
2778 Squid blocks until it receives some replies. Default is 72
2780 When Q1 < Q2 (the default), the cache directory is optimized
2781 for lower response time at the expense of a decrease in hit
2782 ratio. If Q1 > Q2, the cache directory is optimized for
2783 higher hit ratio at the expense of an increase in response
2786 The rock store type:
2788 cache_dir rock Directory-Name Mbytes <max-size=bytes> [options]
2790 The Rock Store type is a database-style storage. All cached
2791 entries are stored in a "database" file, using fixed-size slots,
2792 one entry per slot. The database size is specified in MB. The
2793 slot size is specified in bytes using the max-size option. See
2794 below for more info on the max-size option.
2796 swap-timeout=msec: Squid will not start writing a miss to or
2797 reading a hit from disk if it estimates that the swap operation
2798 will take more than the specified number of milliseconds. By
2799 default and when set to zero, disables the disk I/O time limit
2800 enforcement. Ignored when using blocking I/O module because
2801 blocking synchronous I/O does not allow Squid to estimate the
2802 expected swap wait time.
2804 max-swap-rate=swaps/sec: Artificially limits disk access using
2805 the specified I/O rate limit. Swap out requests that
2806 would cause the average I/O rate to exceed the limit are
2807 delayed. Individual swap in requests (i.e., hits or reads) are
2808 not delayed, but they do contribute to measured swap rate and
2809 since they are placed in the same FIFO queue as swap out
2810 requests, they may wait longer if max-swap-rate is smaller.
2811 This is necessary on file systems that buffer "too
2812 many" writes and then start blocking Squid and other processes
2813 while committing those writes to disk. Usually used together
2814 with swap-timeout to avoid excessive delays and queue overflows
2815 when disk demand exceeds available disk "bandwidth". By default
2816 and when set to zero, disables the disk I/O rate limit
2817 enforcement. Currently supported by IpcIo module only.
2820 The coss store type:
2822 NP: COSS filesystem in Squid-3 has been deemed too unstable for
2823 production use and has thus been removed from this release.
2824 We hope that it can be made usable again soon.
2826 block-size=n defines the "block size" for COSS cache_dir's.
2827 Squid uses file numbers as block numbers. Since file numbers
2828 are limited to 24 bits, the block size determines the maximum
2829 size of the COSS partition. The default is 512 bytes, which
2830 leads to a maximum cache_dir size of 512<<24, or 8 GB. Note
2831 you should not change the coss block size after Squid
2832 has written some objects to the cache_dir.
2834 The coss file store has changed from 2.5. Now it uses a file
2835 called 'stripe' in the directory names in the config - and
2836 this will be created by squid -z.
2840 no-store, no new objects should be stored to this cache_dir
2842 min-size=n, refers to the min object size in bytes this cache_dir
2843 will accept. It's used to restrict a cache_dir to only store
2844 large objects (e.g. aufs) while other storedirs are optimized
2845 for smaller objects (e.g. COSS). Defaults to 0.
2847 max-size=n, refers to the max object size in bytes this cache_dir
2848 supports. It is used to select the cache_dir to store the object.
2849 Note: To make optimal use of the max-size limits you should order
2850 the cache_dir lines with the smallest max-size value first and the
2851 ones with no max-size specification last.
2853 Note for coss, max-size must be less than COSS_MEMBUF_SZ,
2854 which can be changed with the --with-coss-membuf-size=N configure
2858 # Uncomment and adjust the following to add a disk cache directory.
2859 #cache_dir ufs @DEFAULT_SWAP_DIR@ 100 16 256
2863 NAME: store_dir_select_algorithm
2865 LOC: Config.store_dir_select_algorithm
2868 Set this to 'round-robin' as an alternative.
2871 NAME: max_open_disk_fds
2873 LOC: Config.max_open_disk_fds
2876 To avoid having disk as the I/O bottleneck Squid can optionally
2877 bypass the on-disk cache if more than this amount of disk file
2878 descriptors are open.
2880 A value of 0 indicates no limit.
2883 NAME: minimum_object_size
2887 LOC: Config.Store.minObjectSize
2889 Objects smaller than this size will NOT be saved on disk. The
2890 value is specified in kilobytes, and the default is 0 KB, which
2891 means there is no minimum.
2894 NAME: maximum_object_size
2898 LOC: Config.Store.maxObjectSize
2900 Objects larger than this size will NOT be saved on disk. The
2901 value is specified in kilobytes, and the default is 4MB. If
2902 you wish to get a high BYTES hit ratio, you should probably
2903 increase this (one 32 MB object hit counts for 3200 10KB
2904 hits). If you wish to increase speed more than your want to
2905 save bandwidth you should leave this low.
2907 NOTE: if using the LFUDA replacement policy you should increase
2908 this value to maximize the byte hit rate improvement of LFUDA!
2909 See replacement_policy below for a discussion of this policy.
2912 NAME: cache_swap_low
2913 COMMENT: (percent, 0-100)
2916 LOC: Config.Swap.lowWaterMark
2919 NAME: cache_swap_high
2920 COMMENT: (percent, 0-100)
2923 LOC: Config.Swap.highWaterMark
2926 The low- and high-water marks for cache object replacement.
2927 Replacement begins when the swap (disk) usage is above the
2928 low-water mark and attempts to maintain utilization near the
2929 low-water mark. As swap utilization gets close to high-water
2930 mark object eviction becomes more aggressive. If utilization is
2931 close to the low-water mark less replacement is done each time.
2933 Defaults are 90% and 95%. If you have a large cache, 5% could be
2934 hundreds of MB. If this is the case you may wish to set these
2935 numbers closer together.
2940 -----------------------------------------------------------------------------
2950 logformat <name> <format specification>
2952 Defines an access log format.
2954 The <format specification> is a string with embedded % format codes
2956 % format codes all follow the same basic structure where all but
2957 the formatcode is optional. Output strings are automatically escaped
2958 as required according to their context and the output format
2959 modifiers are usually not needed, but can be specified if an explicit
2960 output format is desired.
2962 % ["|[|'|#] [-] [[0]width] [{argument}] formatcode
2964 " output in quoted string format
2965 [ output in squid text log format as used by log_mime_hdrs
2966 # output in URL quoted format
2971 width minimum and/or maximum field width:
2972 [width_min][.width_max]
2973 When minimum starts with 0, the field is zero-padded.
2974 String values exceeding maximum width are truncated.
2976 {arg} argument such as header name etc
2980 % a literal % character
2981 sn Unique sequence number per log line entry
2982 err_code The ID of an error response served by Squid or
2983 a similar internal error identifier.
2984 err_detail Additional err_code-dependent error information.
2986 Connection related format codes:
2988 >a Client source IP address
2990 >p Client source port
2991 >eui Client source EUI (MAC address, EUI-48 or EUI-64 identifier)
2992 >la Local IP address the client connected to
2993 >lp Local port number the client connected to
2995 la Local listening IP address the client connection was connected to.
2996 lp Local listening port number the client connection was connected to.
2998 <a Server IP address of the last server or peer connection
2999 <A Server FQDN or peer name
3000 <p Server port number of the last server or peer connection
3001 <la Local IP address of the last server or peer connection
3002 <lp Local port number of the last server or peer connection
3004 Time related format codes:
3006 ts Seconds since epoch
3007 tu subsecond time (milliseconds)
3008 tl Local time. Optional strftime format argument
3009 default %d/%b/%Y:%H:%M:%S %z
3010 tg GMT time. Optional strftime format argument
3011 default %d/%b/%Y:%H:%M:%S %z
3012 tr Response time (milliseconds)
3013 dt Total time spent making DNS lookups (milliseconds)
3015 Access Control related format codes:
3017 et Tag returned by external acl
3018 ea Log string returned by external acl
3019 un User name (any available)
3020 ul User name from authentication
3021 ue User name from external acl helper
3022 ui User name from ident
3023 us User name from SSL
3025 HTTP related format codes:
3027 [http::]>h Original request header. Optional header name argument
3028 on the format header[:[separator]element]
3029 [http::]>ha The HTTP request headers after adaptation and redirection.
3030 Optional header name argument as for >h
3031 [http::]<h Reply header. Optional header name argument
3033 [http::]>Hs HTTP status code sent to the client
3034 [http::]<Hs HTTP status code received from the next hop
3035 [http::]<bs Number of HTTP-equivalent message body bytes
3036 received from the next hop, excluding chunked
3037 transfer encoding and control messages.
3038 Generated FTP/Gopher listings are treated as
3040 [http::]mt MIME content type
3041 [http::]rm Request method (GET/POST etc)
3042 [http::]>rm Request method from client
3043 [http::]<rm Request method sent to server or peer
3044 [http::]ru Request URL from client (historic, filtered for logging)
3045 [http::]>ru Request URL from client
3046 [http::]<ru Request URL sent to server or peer
3047 [http::]rp Request URL-Path excluding hostname
3048 [http::]>rp Request URL-Path excluding hostname from client
3049 [http::]<rp Request URL-Path excluding hostname sento to server or peer
3050 [http::]rv Request protocol version
3051 [http::]>rv Request protocol version from client
3052 [http::]<rv Request protocol version sent to server or peer
3053 [http::]<st Sent reply size including HTTP headers
3054 [http::]>st Received request size including HTTP headers. In the
3055 case of chunked requests the chunked encoding metadata
3057 [http::]>sh Received HTTP request headers size
3058 [http::]<sh Sent HTTP reply headers size
3059 [http::]st Request+Reply size including HTTP headers
3060 [http::]<sH Reply high offset sent
3061 [http::]<sS Upstream object size
3062 [http::]<pt Peer response time in milliseconds. The timer starts
3063 when the last request byte is sent to the next hop
3064 and stops when the last response byte is received.
3065 [http::]<tt Total server-side time in milliseconds. The timer
3066 starts with the first connect request (or write I/O)
3067 sent to the first selected peer. The timer stops
3068 with the last I/O with the last peer.
3070 Squid handling related format codes:
3072 Ss Squid request status (TCP_MISS etc)
3073 Sh Squid hierarchy status (DEFAULT_PARENT etc)
3075 If ICAP is enabled, the following code becomes available (as
3076 well as ICAP log codes documented with the icap_log option):
3078 icap::tt Total ICAP processing time for the HTTP
3079 transaction. The timer ticks when ICAP
3080 ACLs are checked and when ICAP
3081 transaction is in progress.
3083 If adaptation is enabled the following three codes become available:
3085 adapt::<last_h The header of the last ICAP response or
3086 meta-information from the last eCAP
3087 transaction related to the HTTP transaction.
3088 Like <h, accepts an optional header name
3091 adapt::sum_trs Summed adaptation transaction response
3092 times recorded as a comma-separated list in
3093 the order of transaction start time. Each time
3094 value is recorded as an integer number,
3095 representing response time of one or more
3096 adaptation (ICAP or eCAP) transaction in
3097 milliseconds. When a failed transaction is
3098 being retried or repeated, its time is not
3099 logged individually but added to the
3100 replacement (next) transaction. See also:
3103 adapt::all_trs All adaptation transaction response times.
3104 Same as adaptation_strs but response times of
3105 individual transactions are never added
3106 together. Instead, all transaction response
3107 times are recorded individually.
3109 You can prefix adapt::*_trs format codes with adaptation
3110 service name in curly braces to record response time(s) specific
3111 to that service. For example: %{my_service}adapt::sum_trs
3113 The default formats available (which do not need re-defining) are:
3115 logformat squid %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %[un %Sh/%<a %mt
3116 logformat common %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st %Ss:%Sh
3117 logformat combined %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
3118 logformat referrer %ts.%03tu %>a %{Referer}>h %ru
3119 logformat useragent %>a [%tl] "%{User-Agent}>h"
3121 NOTE: When the log_mime_hdrs directive is set to ON.
3122 The squid, common and combined formats have a safely encoded copy
3123 of the mime headers appended to each line within a pair of brackets.
3125 NOTE: The common and combined formats are not quite true to the Apache definition.
3126 The logs from Squid contain an extra status and hierarchy code appended.
3130 NAME: access_log cache_access_log
3132 LOC: Config.Log.accesslogs
3133 DEFAULT_IF_NONE: daemon:@DEFAULT_ACCESS_LOG@ squid
3135 These files log client request activities. Has a line every HTTP or
3136 ICP request. The format is:
3137 access_log <module>:<place> [<logformat name> [acl acl ...]]
3138 access_log none [acl acl ...]]
3140 Will log to the specified module:place using the specified format (which
3141 must be defined in a logformat directive) those entries which match
3142 ALL the acl's specified (which must be defined in acl clauses).
3143 If no acl is specified, all requests will be logged to this destination.
3145 ===== Modules Currently available =====
3147 none Do not log any requests matching these ACL.
3148 Do not specify Place or logformat name.
3150 stdio Write each log line to disk immediately at the completion of
3152 Place: the filename and path to be written.
3154 daemon Very similar to stdio. But instead of writing to disk the log
3155 line is passed to a daemon helper for asychronous handling instead.
3156 Place: varies depending on the daemon.
3158 log_file_daemon Place: the file name and path to be written.
3160 syslog To log each request via syslog facility.
3161 Place: The syslog facility and priority level for these entries.
3162 Place Format: facility.priority
3164 where facility could be any of:
3165 authpriv, daemon, local0 ... local7 or user.
3167 And priority could be any of:
3168 err, warning, notice, info, debug.
3170 udp To send each log line as text data to a UDP receiver.
3171 Place: The destination host name or IP and port.
3172 Place Format: //host:port
3174 tcp To send each log line as text data to a TCP receiver.
3175 Place: The destination host name or IP and port.
3176 Place Format: //host:port
3179 access_log daemon:@DEFAULT_ACCESS_LOG@ squid
3185 LOC: Config.Log.icaplogs
3188 ICAP log files record ICAP transaction summaries, one line per
3191 The icap_log option format is:
3192 icap_log <filepath> [<logformat name> [acl acl ...]]
3193 icap_log none [acl acl ...]]
3195 Please see access_log option documentation for details. The two
3196 kinds of logs share the overall configuration approach and many
3199 ICAP processing of a single HTTP message or transaction may
3200 require multiple ICAP transactions. In such cases, multiple
3201 ICAP transaction log lines will correspond to a single access
3204 ICAP log uses logformat codes that make sense for an ICAP
3205 transaction. Header-related codes are applied to the HTTP header
3206 embedded in an ICAP server response, with the following caveats:
3207 For REQMOD, there is no HTTP response header unless the ICAP
3208 server performed request satisfaction. For RESPMOD, the HTTP
3209 request header is the header sent to the ICAP server. For
3210 OPTIONS, there are no HTTP headers.
3212 The following format codes are also available for ICAP logs:
3214 icap::<A ICAP server IP address. Similar to <A.
3216 icap::<service_name ICAP service name from the icap_service
3217 option in Squid configuration file.
3219 icap::ru ICAP Request-URI. Similar to ru.
3221 icap::rm ICAP request method (REQMOD, RESPMOD, or
3222 OPTIONS). Similar to existing rm.
3224 icap::>st Bytes sent to the ICAP server (TCP payload
3225 only; i.e., what Squid writes to the socket).
3227 icap::<st Bytes received from the ICAP server (TCP
3228 payload only; i.e., what Squid reads from
3231 icap::<bs Number of message body bytes received from the
3232 ICAP server. ICAP message body, if any, usually
3233 includes encapsulated HTTP message headers and
3234 possibly encapsulated HTTP message body. The
3235 HTTP body part is dechunked before its size is
3238 icap::tr Transaction response time (in
3239 milliseconds). The timer starts when
3240 the ICAP transaction is created and
3241 stops when the transaction is completed.
3244 icap::tio Transaction I/O time (in milliseconds). The
3245 timer starts when the first ICAP request
3246 byte is scheduled for sending. The timers
3247 stops when the last byte of the ICAP response
3250 icap::to Transaction outcome: ICAP_ERR* for all
3251 transaction errors, ICAP_OPT for OPTION
3252 transactions, ICAP_ECHO for 204
3253 responses, ICAP_MOD for message
3254 modification, and ICAP_SAT for request
3255 satisfaction. Similar to Ss.
3257 icap::Hs ICAP response status code. Similar to Hs.
3259 icap::>h ICAP request header(s). Similar to >h.
3261 icap::<h ICAP response header(s). Similar to <h.
3263 The default ICAP log format, which can be used without an explicit
3264 definition, is called icap_squid:
3266 logformat icap_squid %ts.%03tu %6icap::tr %>a %icap::to/%03icap::Hs %icap::<size %icap::rm %icap::ru% %un -/%icap::<A -
3268 See also: logformat, log_icap, and %adapt::<last_h
3271 NAME: logfile_daemon
3273 DEFAULT: @DEFAULT_LOGFILED@
3274 LOC: Log::TheConfig.logfile_daemon
3276 Specify the path to the logfile-writing daemon. This daemon is
3277 used to write the access and store logs, if configured.
3279 Squid sends a number of commands to the log daemon:
3280 L<data>\n - logfile data
3285 r<n>\n - set rotate count to <n>
3286 b<n>\n - 1 = buffer output, 0 = don't buffer output
3288 No responses is expected.
3293 LOC: Config.accessList.log
3295 COMMENT: allow|deny acl acl...
3297 This options allows you to control which requests gets logged
3298 to access.log (see access_log directive). Requests denied for
3299 logging will also not be accounted for in performance counters.
3301 This clause only supports fast acl types.
3302 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
3308 LOC: Config.accessList.icap
3311 This options allows you to control which requests get logged
3312 to icap.log. See the icap_log directive for ICAP log details.
3315 NAME: cache_store_log
3318 LOC: Config.Log.store
3320 Logs the activities of the storage manager. Shows which
3321 objects are ejected from the cache, and which objects are
3322 saved and for how long. To disable, enter "none" or remove the line.
3323 There are not really utilities to analyze this data, so you can safely
3327 cache_store_log @DEFAULT_STORE_LOG@
3330 NAME: cache_swap_state cache_swap_log
3332 LOC: Config.Log.swap
3335 Location for the cache "swap.state" file. This index file holds
3336 the metadata of objects saved on disk. It is used to rebuild
3337 the cache during startup. Normally this file resides in each
3338 'cache_dir' directory, but you may specify an alternate
3339 pathname here. Note you must give a full filename, not just
3340 a directory. Since this is the index for the whole object
3341 list you CANNOT periodically rotate it!
3343 If %s can be used in the file name it will be replaced with a
3344 a representation of the cache_dir name where each / is replaced
3345 with '.'. This is needed to allow adding/removing cache_dir
3346 lines when cache_swap_log is being used.
3348 If have more than one 'cache_dir', and %s is not used in the name
3349 these swap logs will have names such as:
3355 The numbered extension (which is added automatically)
3356 corresponds to the order of the 'cache_dir' lines in this
3357 configuration file. If you change the order of the 'cache_dir'
3358 lines in this file, these index files will NOT correspond to
3359 the correct 'cache_dir' entry (unless you manually rename
3360 them). We recommend you do NOT use this option. It is
3361 better to keep these index files in each 'cache_dir' directory.
3364 NAME: logfile_rotate
3367 LOC: Config.Log.rotateNumber
3369 Specifies the number of logfile rotations to make when you
3370 type 'squid -k rotate'. The default is 10, which will rotate
3371 with extensions 0 through 9. Setting logfile_rotate to 0 will
3372 disable the file name rotation, but the logfiles are still closed
3373 and re-opened. This will enable you to rename the logfiles
3374 yourself just before sending the rotate signal.
3376 Note, the 'squid -k rotate' command normally sends a USR1
3377 signal to the running squid process. In certain situations
3378 (e.g. on Linux with Async I/O), USR1 is used for other
3379 purposes, so -k rotate uses another signal. It is best to get
3380 in the habit of using 'squid -k rotate' instead of 'kill -USR1
3383 Note, from Squid-3.1 this option has no effect on the cache.log,
3384 that log can be rotated separately by using debug_options
3387 NAME: emulate_httpd_log
3390 Replace this with an access_log directive using the format 'common' or 'combined'.
3393 NAME: log_ip_on_direct
3396 Remove this option from your config. To log server or peer names use %<A in the log format.
3401 DEFAULT: @DEFAULT_MIME_TABLE@
3402 LOC: Config.mimeTablePathname
3404 Pathname to Squid's MIME table. You shouldn't need to change
3405 this, but the default file contains examples and formatting
3406 information if you do.
3412 LOC: Config.onoff.log_mime_hdrs
3415 The Cache can record both the request and the response MIME
3416 headers for each HTTP transaction. The headers are encoded
3417 safely and will appear as two bracketed fields at the end of
3418 the access log (for either the native or httpd-emulated log
3419 formats). To enable this logging set log_mime_hdrs to 'on'.
3425 Replace this with an access_log directive using the format 'useragent'.
3428 NAME: referer_log referrer_log
3431 Replace this with an access_log directive using the format 'referrer'.
3436 DEFAULT: @DEFAULT_PID_FILE@
3437 LOC: Config.pidFilename
3439 A filename to write the process-id to. To disable, enter "none".
3445 Remove this option from your config. To log FQDN use %>A in the log format.
3448 NAME: client_netmask
3450 LOC: Config.Addrs.client_netmask
3453 A netmask for client addresses in logfiles and cachemgr output.
3454 Change this to protect the privacy of your cache clients.
3455 A netmask of 255.255.255.0 will log all IP's in that range with
3456 the last digit set to '0'.
3462 Use a regular access.log with ACL limiting it to MISS events.
3465 NAME: strip_query_terms
3467 LOC: Config.onoff.strip_query_terms
3470 By default, Squid strips query terms from requested URLs before
3471 logging. This protects your user's privacy.
3478 LOC: Config.onoff.buffered_logs
3480 cache.log log file is written with stdio functions, and as such
3481 it can be buffered or unbuffered. By default it will be unbuffered.
3482 Buffering it can speed up the writing slightly (though you are
3483 unlikely to need to worry unless you run with tons of debugging
3484 enabled in which case performance will suffer badly anyway..).
3487 NAME: netdb_filename
3489 DEFAULT: stdio:@DEFAULT_NETDB_FILE@
3490 LOC: Config.netdbFilename
3493 A filename where Squid stores it's netdb state between restarts.
3494 To disable, enter "none".
3498 OPTIONS FOR TROUBLESHOOTING
3499 -----------------------------------------------------------------------------
3504 DEFAULT_IF_NONE: @DEFAULT_CACHE_LOG@
3505 LOC: Debug::cache_log
3507 Cache logging file. This is where general information about
3508 your cache's behavior goes. You can increase the amount of data
3509 logged to this file and how often its rotated with "debug_options"
3515 LOC: Debug::debugOptions
3517 Logging options are set as section,level where each source file
3518 is assigned a unique section. Lower levels result in less
3519 output, Full debugging (level 9) can result in a very large
3520 log file, so be careful.
3522 The magic word "ALL" sets debugging levels for all sections.
3523 We recommend normally running with "ALL,1".
3525 The rotate=N option can be used to keep more or less of these logs
3526 than would otherwise be kept by logfile_rotate.
3527 For most uses a single log should be enough to monitor current
3528 events affecting Squid.
3533 LOC: Config.coredump_dir
3534 DEFAULT_IF_NONE: none
3536 By default Squid leaves core files in the directory from where
3537 it was started. If you set 'coredump_dir' to a directory
3538 that exists, Squid will chdir() to that directory at startup
3539 and coredump files will be left there.
3543 # Leave coredumps in the first cache dir
3544 coredump_dir @DEFAULT_SWAP_DIR@
3550 OPTIONS FOR FTP GATEWAYING
3551 -----------------------------------------------------------------------------
3557 LOC: Config.Ftp.anon_user
3559 If you want the anonymous login password to be more informative
3560 (and enable the use of picky ftp servers), set this to something
3561 reasonable for your domain, like wwwuser@somewhere.net
3563 The reason why this is domainless by default is the
3564 request can be made on the behalf of a user in any domain,
3565 depending on how the cache is used.
3566 Some ftp server also validate the email address is valid
3567 (for example perl.com).
3573 LOC: Config.Ftp.passive
3575 If your firewall does not allow Squid to use passive
3576 connections, turn off this option.
3578 Use of ftp_epsv_all option requires this to be ON.
3584 LOC: Config.Ftp.epsv_all
3586 FTP Protocol extensions permit the use of a special "EPSV ALL" command.
3588 NATs may be able to put the connection on a "fast path" through the
3589 translator, as the EPRT command will never be used and therefore,
3590 translation of the data portion of the segments will never be needed.
3592 When a client only expects to do two-way FTP transfers this may be
3594 If squid finds that it must do a three-way FTP transfer after issuing
3595 an EPSV ALL command, the FTP session will fail.
3597 If you have any doubts about this option do not use it.
3598 Squid will nicely attempt all other connection methods.
3600 Requires ftp_passive to be ON (default) for any effect.
3606 LOC: Config.Ftp.epsv
3608 FTP Protocol extensions permit the use of a special "EPSV" command.
3610 NATs may be able to put the connection on a "fast path" through the
3611 translator using EPSV, as the EPRT command will never be used
3612 and therefore, translation of the data portion of the segments
3613 will never be needed.
3615 Turning this OFF will prevent EPSV being attempted.
3616 WARNING: Doing so will convert Squid back to the old behavior with all
3617 the related problems with external NAT devices/layers.
3619 Requires ftp_passive to be ON (default) for any effect.
3625 LOC: Config.Ftp.eprt
3627 FTP Protocol extensions permit the use of a special "EPRT" command.
3629 This extension provides a protocol neutral alternative to the
3630 IPv4-only PORT command. When supported it enables active FTP data
3631 channels over IPv6 and efficient NAT handling.
3633 Turning this OFF will prevent EPRT being attempted and will skip
3634 straight to using PORT for IPv4 servers.
3636 Some devices are known to not handle this extension correctly and
3637 may result in crashes. Devices which suport EPRT enough to fail
3638 cleanly will result in Squid attempting PORT anyway. This directive
3639 should only be disabled when EPRT results in device failures.
3641 WARNING: Doing so will convert Squid back to the old behavior with all
3642 the related problems with external NAT devices/layers and IPv4-only FTP.
3645 NAME: ftp_sanitycheck
3648 LOC: Config.Ftp.sanitycheck
3650 For security and data integrity reasons Squid by default performs
3651 sanity checks of the addresses of FTP data connections ensure the
3652 data connection is to the requested server. If you need to allow
3653 FTP connections to servers using another IP address for the data
3654 connection turn this off.
3657 NAME: ftp_telnet_protocol
3660 LOC: Config.Ftp.telnet
3662 The FTP protocol is officially defined to use the telnet protocol
3663 as transport channel for the control connection. However, many
3664 implementations are broken and does not respect this aspect of
3667 If you have trouble accessing files with ASCII code 255 in the
3668 path or similar problems involving this ASCII code you can
3669 try setting this directive to off. If that helps, report to the
3670 operator of the FTP server in question that their FTP server
3671 is broken and does not follow the FTP standard.
3675 OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
3676 -----------------------------------------------------------------------------
3681 DEFAULT: @DEFAULT_DISKD@
3682 LOC: Config.Program.diskd
3684 Specify the location of the diskd executable.
3685 Note this is only useful if you have compiled in
3686 diskd as one of the store io modules.
3689 NAME: unlinkd_program
3692 DEFAULT: @DEFAULT_UNLINKD@
3693 LOC: Config.Program.unlinkd
3695 Specify the location of the executable for file deletion process.
3698 NAME: pinger_program
3700 DEFAULT: @DEFAULT_PINGER@
3701 LOC: Config.pinger.program
3704 Specify the location of the executable for the pinger process.
3710 LOC: Config.pinger.enable
3713 Control whether the pinger is active at run-time.
3714 Enables turning ICMP pinger on and off with a simple
3715 squid -k reconfigure.
3720 OPTIONS FOR URL REWRITING
3721 -----------------------------------------------------------------------------
3724 NAME: url_rewrite_program redirect_program
3726 LOC: Config.Program.redirect
3729 Specify the location of the executable URL rewriter to use.
3730 Since they can perform almost any function there isn't one included.
3732 For each requested URL, the rewriter will receive on line with the format
3734 URL <SP> client_ip "/" fqdn <SP> user <SP> method [<SP> kvpairs]<NL>
3736 In the future, the rewriter interface will be extended with
3737 key=value pairs ("kvpairs" shown above). Rewriter programs
3738 should be prepared to receive and possibly ignore additional
3739 whitespace-separated tokens on each input line.
3741 And the rewriter may return a rewritten URL. The other components of
3742 the request line does not need to be returned (ignored if they are).
3744 The rewriter can also indicate that a client-side redirect should
3745 be performed to the new URL. This is done by prefixing the returned
3746 URL with "301:" (moved permanently) or 302: (moved temporarily), etc.
3748 By default, a URL rewriter is not used.
3751 NAME: url_rewrite_children redirect_children
3752 TYPE: HelperChildConfig
3753 DEFAULT: 20 startup=0 idle=1 concurrency=0
3754 LOC: Config.redirectChildren
3756 The maximum number of redirector processes to spawn. If you limit
3757 it too few Squid will have to wait for them to process a backlog of
3758 URLs, slowing it down. If you allow too many they will use RAM
3759 and other system resources noticably.
3761 The startup= and idle= options allow some measure of skew in your
3766 Sets a minimum of how many processes are to be spawned when Squid
3767 starts or reconfigures. When set to zero the first request will
3768 cause spawning of the first child process to handle it.
3770 Starting too few will cause an initial slowdown in traffic as Squid
3771 attempts to simultaneously spawn enough processes to cope.
3775 Sets a minimum of how many processes Squid is to try and keep available
3776 at all times. When traffic begins to rise above what the existing
3777 processes can handle this many more will be spawned up to the maximum
3778 configured. A minimum setting of 1 is required.
3782 The number of requests each redirector helper can handle in
3783 parallel. Defaults to 0 which indicates the redirector
3784 is a old-style single threaded redirector.
3786 When this directive is set to a value >= 1 then the protocol
3787 used to communicate with the helper is modified to include
3788 a request ID in front of the request/response. The request
3789 ID from the request must be echoed back with the response
3793 NAME: url_rewrite_host_header redirect_rewrites_host_header
3796 LOC: Config.onoff.redir_rewrites_host
3798 To preserve same-origin security policies in browsers and
3799 prevent Host: header forgery by redirectors Squid rewrites
3800 any Host: header in redirected requests.
3802 If you are running an accelerator this may not be a wanted
3803 effect of a redirector. This directive enables you disable
3804 Host: alteration in reverse-proxy traffic.
3806 WARNING: Entries are cached on the result of the URL rewriting
3807 process, so be careful if you have domain-virtual hosts.
3809 WARNING: Squid and other software verifies the URL and Host
3810 are matching, so be careful not to relay through other proxies
3811 or inspecting firewalls with this disabled.
3814 NAME: url_rewrite_access redirector_access
3817 LOC: Config.accessList.redirector
3819 If defined, this access list specifies which requests are
3820 sent to the redirector processes. By default all requests
3823 This clause supports both fast and slow acl types.
3824 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
3827 NAME: url_rewrite_bypass redirector_bypass
3829 LOC: Config.onoff.redirector_bypass
3832 When this is 'on', a request will not go through the
3833 redirector if all redirectors are busy. If this is 'off'
3834 and the redirector queue grows too large, Squid will exit
3835 with a FATAL error and ask you to increase the number of
3836 redirectors. You should only enable this if the redirectors
3837 are not critical to your caching system. If you use
3838 redirectors for access control, and you enable this option,
3839 users may have access to pages they should not
3840 be allowed to request.
3844 OPTIONS FOR TUNING THE CACHE
3845 -----------------------------------------------------------------------------
3848 NAME: cache no_cache
3851 LOC: Config.accessList.noCache
3853 A list of ACL elements which, if matched and denied, cause the request to
3854 not be satisfied from the cache and the reply to not be cached.
3855 In other words, use this to force certain objects to never be cached.
3857 You must use the words 'allow' or 'deny' to indicate whether items
3858 matching the ACL should be allowed or denied into the cache.
3860 Default is to allow all to be cached.
3862 This clause supports both fast and slow acl types.
3863 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
3869 LOC: Config.maxStale
3872 This option puts an upper limit on how stale content Squid
3873 will serve from the cache if cache validation fails.
3874 Can be overriden by the refresh_pattern max-stale option.
3877 NAME: refresh_pattern
3878 TYPE: refreshpattern
3882 usage: refresh_pattern [-i] regex min percent max [options]
3884 By default, regular expressions are CASE-SENSITIVE. To make
3885 them case-insensitive, use the -i option.
3887 'Min' is the time (in minutes) an object without an explicit
3888 expiry time should be considered fresh. The recommended
3889 value is 0, any higher values may cause dynamic applications
3890 to be erroneously cached unless the application designer
3891 has taken the appropriate actions.
3893 'Percent' is a percentage of the objects age (time since last
3894 modification age) an object without explicit expiry time
3895 will be considered fresh.
3897 'Max' is an upper limit on how long objects without an explicit
3898 expiry time will be considered fresh.
3900 options: override-expire
3906 ignore-must-revalidate
3913 override-expire enforces min age even if the server
3914 sent an explicit expiry time (e.g., with the
3915 Expires: header or Cache-Control: max-age). Doing this
3916 VIOLATES the HTTP standard. Enabling this feature
3917 could make you liable for problems which it causes.
3919 Note: override-expire does not enforce staleness - it only extends
3920 freshness / min. If the server returns a Expires time which
3921 is longer than your max time, Squid will still consider
3922 the object fresh for that period of time.
3924 override-lastmod enforces min age even on objects
3925 that were modified recently.
3927 reload-into-ims changes client no-cache or ``reload''
3928 to If-Modified-Since requests. Doing this VIOLATES the
3929 HTTP standard. Enabling this feature could make you
3930 liable for problems which it causes.
3932 ignore-reload ignores a client no-cache or ``reload''
3933 header. Doing this VIOLATES the HTTP standard. Enabling
3934 this feature could make you liable for problems which
3937 ignore-no-cache ignores any ``Pragma: no-cache'' and
3938 ``Cache-control: no-cache'' headers received from a server.
3939 The HTTP RFC never allows the use of this (Pragma) header
3940 from a server, only a client, though plenty of servers
3943 ignore-no-store ignores any ``Cache-control: no-store''
3944 headers received from a server. Doing this VIOLATES
3945 the HTTP standard. Enabling this feature could make you
3946 liable for problems which it causes.
3948 ignore-must-revalidate ignores any ``Cache-Control: must-revalidate``
3949 headers received from a server. Doing this VIOLATES
3950 the HTTP standard. Enabling this feature could make you
3951 liable for problems which it causes.
3953 ignore-private ignores any ``Cache-control: private''
3954 headers received from a server. Doing this VIOLATES
3955 the HTTP standard. Enabling this feature could make you
3956 liable for problems which it causes.
3958 ignore-auth caches responses to requests with authorization,
3959 as if the originserver had sent ``Cache-control: public''
3960 in the response header. Doing this VIOLATES the HTTP standard.
3961 Enabling this feature could make you liable for problems which
3964 refresh-ims causes squid to contact the origin server
3965 when a client issues an If-Modified-Since request. This
3966 ensures that the client will receive an updated version
3967 if one is available.
3969 store-stale stores responses even if they don't have explicit
3970 freshness or a validator (i.e., Last-Modified or an ETag)
3971 present, or if they're already stale. By default, Squid will
3972 not cache such responses because they usually can't be
3973 reused. Note that such responses will be stale by default.
3975 max-stale=NN provide a maximum staleness factor. Squid won't
3976 serve objects more stale than this even if it failed to
3977 validate the object. Default: use the max_stale global limit.
3979 Basically a cached object is:
3981 FRESH if expires < now, else STALE
3983 FRESH if lm-factor < percent, else STALE
3987 The refresh_pattern lines are checked in the order listed here.
3988 The first entry which matches is used. If none of the entries
3989 match the default will be used.
3991 Note, you must uncomment all the default lines if you want
3992 to change one. The default setting is only active if none is
3997 # Add any of your own refresh_pattern entries above these.
3998 refresh_pattern ^ftp: 1440 20% 10080
3999 refresh_pattern ^gopher: 1440 0% 1440
4000 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0
4001 refresh_pattern . 0 20% 4320
4005 NAME: quick_abort_min
4009 LOC: Config.quickAbort.min
4012 NAME: quick_abort_max
4016 LOC: Config.quickAbort.max
4019 NAME: quick_abort_pct
4023 LOC: Config.quickAbort.pct
4025 The cache by default continues downloading aborted requests
4026 which are almost completed (less than 16 KB remaining). This
4027 may be undesirable on slow (e.g. SLIP) links and/or very busy
4028 caches. Impatient users may tie up file descriptors and
4029 bandwidth by repeatedly requesting and immediately aborting
4032 When the user aborts a request, Squid will check the
4033 quick_abort values to the amount of data transfered until
4036 If the transfer has less than 'quick_abort_min' KB remaining,
4037 it will finish the retrieval.
4039 If the transfer has more than 'quick_abort_max' KB remaining,
4040 it will abort the retrieval.
4042 If more than 'quick_abort_pct' of the transfer has completed,
4043 it will finish the retrieval.
4045 If you do not want any retrieval to continue after the client
4046 has aborted, set both 'quick_abort_min' and 'quick_abort_max'
4049 If you want retrievals to always continue if they are being
4050 cached set 'quick_abort_min' to '-1 KB'.
4053 NAME: read_ahead_gap
4054 COMMENT: buffer-size
4056 LOC: Config.readAheadGap
4059 The amount of data the cache will buffer ahead of what has been
4060 sent to the client when retrieving an object from another server.
4064 IFDEF: USE_HTTP_VIOLATIONS
4067 LOC: Config.negativeTtl
4070 Set the Default Time-to-Live (TTL) for failed requests.
4071 Certain types of failures (such as "connection refused" and
4072 "404 Not Found") are able to be negatively-cached for a short time.
4073 Modern web servers should provide Expires: header, however if they
4074 do not this can provide a minimum TTL.
4075 The default is not to cache errors with unknown expiry details.
4077 Note that this is different from negative caching of DNS lookups.
4079 WARNING: Doing this VIOLATES the HTTP standard. Enabling
4080 this feature could make you liable for problems which it
4084 NAME: positive_dns_ttl
4087 LOC: Config.positiveDnsTtl
4090 Upper limit on how long Squid will cache positive DNS responses.
4091 Default is 6 hours (360 minutes). This directive must be set
4092 larger than negative_dns_ttl.
4095 NAME: negative_dns_ttl
4098 LOC: Config.negativeDnsTtl
4101 Time-to-Live (TTL) for negative caching of failed DNS lookups.
4102 This also sets the lower cache limit on positive lookups.
4103 Minimum value is 1 second, and it is not recommendable to go
4104 much below 10 seconds.
4107 NAME: range_offset_limit
4108 COMMENT: size [acl acl...]
4110 LOC: Config.rangeOffsetLimit
4113 usage: (size) [units] [[!]aclname]
4115 Sets an upper limit on how far (number of bytes) into the file
4116 a Range request may be to cause Squid to prefetch the whole file.
4117 If beyond this limit, Squid forwards the Range request as it is and
4118 the result is NOT cached.
4120 This is to stop a far ahead range request (lets say start at 17MB)
4121 from making Squid fetch the whole object up to that point before
4122 sending anything to the client.
4124 Multiple range_offset_limit lines may be specified, and they will
4125 be searched from top to bottom on each request until a match is found.
4126 The first match found will be used. If no line matches a request, the
4127 default limit of 0 bytes will be used.
4129 'size' is the limit specified as a number of units.
4131 'units' specifies whether to use bytes, KB, MB, etc.
4132 If no units are specified bytes are assumed.
4134 A size of 0 causes Squid to never fetch more than the
4135 client requested. (default)
4137 A size of 'none' causes Squid to always fetch the object from the
4138 beginning so it may cache the result. (2.0 style)
4140 'aclname' is the name of a defined ACL.
4142 NP: Using 'none' as the byte value here will override any quick_abort settings
4143 that may otherwise apply to the range request. The range request will
4144 be fully fetched from start to finish regardless of the client
4145 actions. This affects bandwidth usage.
4148 NAME: minimum_expiry_time
4151 LOC: Config.minimum_expiry_time
4154 The minimum caching time according to (Expires - Date)
4155 Headers Squid honors if the object can't be revalidated
4156 defaults to 60 seconds. In reverse proxy environments it
4157 might be desirable to honor shorter object lifetimes. It
4158 is most likely better to make your server return a
4159 meaningful Last-Modified header however. In ESI environments
4160 where page fragments often have short lifetimes, this will
4161 often be best set to 0.
4164 NAME: store_avg_object_size
4168 LOC: Config.Store.avgObjectSize
4170 Average object size, used to estimate number of objects your
4171 cache can hold. The default is 13 KB.
4174 NAME: store_objects_per_bucket
4177 LOC: Config.Store.objectsPerBucket
4179 Target number of objects per bucket in the store hash table.
4180 Lowering this value increases the total number of buckets and
4181 also the storage maintenance rate. The default is 20.
4186 -----------------------------------------------------------------------------
4189 NAME: request_header_max_size
4193 LOC: Config.maxRequestHeaderSize
4195 This specifies the maximum size for HTTP headers in a request.
4196 Request headers are usually relatively small (about 512 bytes).
4197 Placing a limit on the request header size will catch certain
4198 bugs (for example with persistent connections) and possibly
4199 buffer-overflow or denial-of-service attacks.
4202 NAME: reply_header_max_size
4206 LOC: Config.maxReplyHeaderSize
4208 This specifies the maximum size for HTTP headers in a reply.
4209 Reply headers are usually relatively small (about 512 bytes).
4210 Placing a limit on the reply header size will catch certain
4211 bugs (for example with persistent connections) and possibly
4212 buffer-overflow or denial-of-service attacks.
4215 NAME: request_body_max_size
4219 LOC: Config.maxRequestBodySize
4221 This specifies the maximum size for an HTTP request body.
4222 In other words, the maximum size of a PUT/POST request.
4223 A user who attempts to send a request with a body larger
4224 than this limit receives an "Invalid Request" error message.
4225 If you set this parameter to a zero (the default), there will
4226 be no limit imposed.
4229 NAME: client_request_buffer_max_size
4233 LOC: Config.maxRequestBufferSize
4235 This specifies the maximum buffer size of a client request.
4236 It prevents squid eating too much memory when somebody uploads
4240 NAME: chunked_request_body_max_size
4244 LOC: Config.maxChunkedRequestBodySize
4246 A broken or confused HTTP/1.1 client may send a chunked HTTP
4247 request to Squid. Squid does not have full support for that
4248 feature yet. To cope with such requests, Squid buffers the
4249 entire request and then dechunks request body to create a
4250 plain HTTP/1.0 request with a known content length. The plain
4251 request is then used by the rest of Squid code as usual.
4253 The option value specifies the maximum size of the buffer used
4254 to hold the request before the conversion. If the chunked
4255 request size exceeds the specified limit, the conversion
4256 fails, and the client receives an "unsupported request" error,
4257 as if dechunking was disabled.
4259 Dechunking is enabled by default. To disable conversion of
4260 chunked requests, set the maximum to zero.
4262 Request dechunking feature and this option in particular are a
4263 temporary hack. When chunking requests and responses are fully
4264 supported, there will be no need to buffer a chunked request.
4268 IFDEF: USE_HTTP_VIOLATIONS
4271 LOC: Config.accessList.brokenPosts
4273 A list of ACL elements which, if matched, causes Squid to send
4274 an extra CRLF pair after the body of a PUT/POST request.
4276 Some HTTP servers has broken implementations of PUT/POST,
4277 and rely on an extra CRLF pair sent by some WWW clients.
4279 Quote from RFC2616 section 4.1 on this matter:
4281 Note: certain buggy HTTP/1.0 client implementations generate an
4282 extra CRLF's after a POST request. To restate what is explicitly
4283 forbidden by the BNF, an HTTP/1.1 client must not preface or follow
4284 a request with an extra CRLF.
4286 This clause only supports fast acl types.
4287 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4290 acl buggy_server url_regex ^http://....
4291 broken_posts allow buggy_server
4294 NAME: adaptation_uses_indirect_client icap_uses_indirect_client
4297 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_ADAPTATION
4299 LOC: Adaptation::Config::use_indirect_client
4301 Controls whether the indirect client IP address (instead of the direct
4302 client IP address) is passed to adaptation services.
4304 See also: follow_x_forwarded_for adaptation_send_client_ip
4308 IFDEF: USE_HTTP_VIOLATIONS
4312 LOC: Config.onoff.via
4314 If set (default), Squid will include a Via header in requests and
4315 replies as required by RFC2616.
4321 LOC: Config.onoff.ie_refresh
4324 Microsoft Internet Explorer up until version 5.5 Service
4325 Pack 1 has an issue with transparent proxies, wherein it
4326 is impossible to force a refresh. Turning this on provides
4327 a partial fix to the problem, by causing all IMS-REFRESH
4328 requests from older IE versions to check the origin server
4329 for fresh content. This reduces hit ratio by some amount
4330 (~10% in my experience), but allows users to actually get
4331 fresh content when they want it. Note because Squid
4332 cannot tell if the user is using 5.5 or 5.5SP1, the behavior
4333 of 5.5 is unchanged from old versions of Squid (i.e. a
4334 forced refresh is impossible). Newer versions of IE will,
4335 hopefully, continue to have the new behavior and will be
4336 handled based on that assumption. This option defaults to
4337 the old Squid behavior, which is better for hit ratios but
4338 worse for clients using IE, if they need to be able to
4339 force fresh content.
4342 NAME: vary_ignore_expire
4345 LOC: Config.onoff.vary_ignore_expire
4348 Many HTTP servers supporting Vary gives such objects
4349 immediate expiry time with no cache-control header
4350 when requested by a HTTP/1.0 client. This option
4351 enables Squid to ignore such expiry times until
4352 HTTP/1.1 is fully implemented.
4354 WARNING: If turned on this may eventually cause some
4355 varying objects not intended for caching to get cached.
4358 NAME: request_entities
4360 LOC: Config.onoff.request_entities
4363 Squid defaults to deny GET and HEAD requests with request entities,
4364 as the meaning of such requests are undefined in the HTTP standard
4365 even if not explicitly forbidden.
4367 Set this directive to on if you have clients which insists
4368 on sending request entities in GET or HEAD requests. But be warned
4369 that there is server software (both proxies and web servers) which
4370 can fail to properly process this kind of request which may make you
4371 vulnerable to cache pollution attacks if enabled.
4374 NAME: request_header_access
4375 IFDEF: USE_HTTP_VIOLATIONS
4376 TYPE: http_header_access[]
4377 LOC: Config.request_header_access
4380 Usage: request_header_access header_name allow|deny [!]aclname ...
4382 WARNING: Doing this VIOLATES the HTTP standard. Enabling
4383 this feature could make you liable for problems which it
4386 This option replaces the old 'anonymize_headers' and the
4387 older 'http_anonymizer' option with something that is much
4388 more configurable. This new method creates a list of ACLs
4389 for each header, allowing you very fine-tuned header
4392 This option only applies to request headers, i.e., from the
4393 client to the server.
4395 You can only specify known headers for the header name.
4396 Other headers are reclassified as 'Other'. You can also
4397 refer to all the headers with 'All'.
4399 For example, to achieve the same behavior as the old
4400 'http_anonymizer standard' option, you should use:
4402 request_header_access From deny all
4403 request_header_access Referer deny all
4404 request_header_access Server deny all
4405 request_header_access User-Agent deny all
4406 request_header_access WWW-Authenticate deny all
4407 request_header_access Link deny all
4409 Or, to reproduce the old 'http_anonymizer paranoid' feature
4412 request_header_access Allow allow all
4413 request_header_access Authorization allow all
4414 request_header_access WWW-Authenticate allow all
4415 request_header_access Proxy-Authorization allow all
4416 request_header_access Proxy-Authenticate allow all
4417 request_header_access Cache-Control allow all
4418 request_header_access Content-Encoding allow all
4419 request_header_access Content-Length allow all
4420 request_header_access Content-Type allow all
4421 request_header_access Date allow all
4422 request_header_access Expires allow all
4423 request_header_access Host allow all
4424 request_header_access If-Modified-Since allow all
4425 request_header_access Last-Modified allow all
4426 request_header_access Location allow all
4427 request_header_access Pragma allow all
4428 request_header_access Accept allow all
4429 request_header_access Accept-Charset allow all
4430 request_header_access Accept-Encoding allow all
4431 request_header_access Accept-Language allow all
4432 request_header_access Content-Language allow all
4433 request_header_access Mime-Version allow all
4434 request_header_access Retry-After allow all
4435 request_header_access Title allow all
4436 request_header_access Connection allow all
4437 request_header_access All deny all
4439 although many of those are HTTP reply headers, and so should be
4440 controlled with the reply_header_access directive.
4442 By default, all headers are allowed (no anonymizing is
4446 NAME: reply_header_access
4447 IFDEF: USE_HTTP_VIOLATIONS
4448 TYPE: http_header_access[]
4449 LOC: Config.reply_header_access
4452 Usage: reply_header_access header_name allow|deny [!]aclname ...
4454 WARNING: Doing this VIOLATES the HTTP standard. Enabling
4455 this feature could make you liable for problems which it
4458 This option only applies to reply headers, i.e., from the
4459 server to the client.
4461 This is the same as request_header_access, but in the other
4464 This option replaces the old 'anonymize_headers' and the
4465 older 'http_anonymizer' option with something that is much
4466 more configurable. This new method creates a list of ACLs
4467 for each header, allowing you very fine-tuned header
4470 You can only specify known headers for the header name.
4471 Other headers are reclassified as 'Other'. You can also
4472 refer to all the headers with 'All'.
4474 For example, to achieve the same behavior as the old
4475 'http_anonymizer standard' option, you should use:
4477 reply_header_access From deny all
4478 reply_header_access Referer deny all
4479 reply_header_access Server deny all
4480 reply_header_access User-Agent deny all
4481 reply_header_access WWW-Authenticate deny all
4482 reply_header_access Link deny all
4484 Or, to reproduce the old 'http_anonymizer paranoid' feature
4487 reply_header_access Allow allow all
4488 reply_header_access Authorization allow all
4489 reply_header_access WWW-Authenticate allow all
4490 reply_header_access Proxy-Authorization allow all
4491 reply_header_access Proxy-Authenticate allow all
4492 reply_header_access Cache-Control allow all
4493 reply_header_access Content-Encoding allow all
4494 reply_header_access Content-Length allow all
4495 reply_header_access Content-Type allow all
4496 reply_header_access Date allow all
4497 reply_header_access Expires allow all
4498 reply_header_access Host allow all
4499 reply_header_access If-Modified-Since allow all
4500 reply_header_access Last-Modified allow all
4501 reply_header_access Location allow all
4502 reply_header_access Pragma allow all
4503 reply_header_access Accept allow all
4504 reply_header_access Accept-Charset allow all
4505 reply_header_access Accept-Encoding allow all
4506 reply_header_access Accept-Language allow all
4507 reply_header_access Content-Language allow all
4508 reply_header_access Mime-Version allow all
4509 reply_header_access Retry-After allow all
4510 reply_header_access Title allow all
4511 reply_header_access Connection allow all
4512 reply_header_access All deny all
4514 although the HTTP request headers won't be usefully controlled
4515 by this directive -- see request_header_access for details.
4517 By default, all headers are allowed (no anonymizing is
4521 NAME: request_header_replace header_replace
4522 IFDEF: USE_HTTP_VIOLATIONS
4523 TYPE: http_header_replace[]
4524 LOC: Config.request_header_access
4527 Usage: request_header_replace header_name message
4528 Example: request_header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
4530 This option allows you to change the contents of headers
4531 denied with request_header_access above, by replacing them
4532 with some fixed string. This replaces the old fake_user_agent
4535 This only applies to request headers, not reply headers.
4537 By default, headers are removed if denied.
4540 NAME: reply_header_replace
4541 IFDEF: USE_HTTP_VIOLATIONS
4542 TYPE: http_header_replace[]
4543 LOC: Config.reply_header_access
4546 Usage: reply_header_replace header_name message
4547 Example: reply_header_replace Server Foo/1.0
4549 This option allows you to change the contents of headers
4550 denied with reply_header_access above, by replacing them
4551 with some fixed string.
4553 This only applies to reply headers, not request headers.
4555 By default, headers are removed if denied.
4558 NAME: relaxed_header_parser
4559 COMMENT: on|off|warn
4561 LOC: Config.onoff.relaxed_header_parser
4564 In the default "on" setting Squid accepts certain forms
4565 of non-compliant HTTP messages where it is unambiguous
4566 what the sending application intended even if the message
4567 is not correctly formatted. The messages is then normalized
4568 to the correct form when forwarded by Squid.
4570 If set to "warn" then a warning will be emitted in cache.log
4571 each time such HTTP error is encountered.
4573 If set to "off" then such HTTP errors will cause the request
4574 or response to be rejected.
4579 -----------------------------------------------------------------------------
4582 NAME: forward_timeout
4585 LOC: Config.Timeout.forward
4588 This parameter specifies how long Squid should at most attempt in
4589 finding a forwarding path for the request before giving up.
4592 NAME: connect_timeout
4595 LOC: Config.Timeout.connect
4598 This parameter specifies how long to wait for the TCP connect to
4599 the requested server or peer to complete before Squid should
4600 attempt to find another path where to forward the request.
4603 NAME: peer_connect_timeout
4606 LOC: Config.Timeout.peer_connect
4609 This parameter specifies how long to wait for a pending TCP
4610 connection to a peer cache. The default is 30 seconds. You
4611 may also set different timeout values for individual neighbors
4612 with the 'connect-timeout' option on a 'cache_peer' line.
4618 LOC: Config.Timeout.read
4621 The read_timeout is applied on server-side connections. After
4622 each successful read(), the timeout will be extended by this
4623 amount. If no data is read again after this amount of time,
4624 the request is aborted and logged with ERR_READ_TIMEOUT. The
4625 default is 15 minutes.
4631 LOC: Config.Timeout.write
4634 This timeout is tracked for all connections that have data
4635 available for writing and are waiting for the socket to become
4636 ready. After each successful write, the timeout is extended by
4637 the configured amount. If Squid has data to write but the
4638 connection is not ready for the configured duration, the
4639 transaction associated with the connection is terminated. The
4640 default is 15 minutes.
4643 NAME: request_timeout
4645 LOC: Config.Timeout.request
4648 How long to wait for complete HTTP request headers after initial
4649 connection establishment.
4652 NAME: client_idle_pconn_timeout persistent_request_timeout
4654 LOC: Config.Timeout.clientIdlePconn
4657 How long to wait for the next HTTP request on a persistent
4658 client connection after the previous request completes.
4661 NAME: client_lifetime
4664 LOC: Config.Timeout.lifetime
4667 The maximum amount of time a client (browser) is allowed to
4668 remain connected to the cache process. This protects the Cache
4669 from having a lot of sockets (and hence file descriptors) tied up
4670 in a CLOSE_WAIT state from remote clients that go away without
4671 properly shutting down (either because of a network failure or
4672 because of a poor client implementation). The default is one
4675 NOTE: The default value is intended to be much larger than any
4676 client would ever need to be connected to your cache. You
4677 should probably change client_lifetime only as a last resort.
4678 If you seem to have many client connections tying up
4679 filedescriptors, we recommend first tuning the read_timeout,
4680 request_timeout, persistent_request_timeout and quick_abort values.
4683 NAME: half_closed_clients
4685 LOC: Config.onoff.half_closed_clients
4688 Some clients may shutdown the sending side of their TCP
4689 connections, while leaving their receiving sides open. Sometimes,
4690 Squid can not tell the difference between a half-closed and a
4691 fully-closed TCP connection.
4693 By default, Squid will immediately close client connections when
4694 read(2) returns "no more data to read."
4696 Change this option to 'on' and Squid will keep open connections
4697 until a read(2) or write(2) on the socket returns an error.
4698 This may show some benefits for reverse proxies. But if not
4699 it is recommended to leave OFF.
4702 NAME: server_idle_pconn_timeout pconn_timeout
4704 LOC: Config.Timeout.serverIdlePconn
4707 Timeout for idle persistent connections to servers and other
4714 LOC: Ident::TheConfig.timeout
4717 Maximum time to wait for IDENT lookups to complete.
4719 If this is too high, and you enabled IDENT lookups from untrusted
4720 users, you might be susceptible to denial-of-service by having
4721 many ident requests going at once.
4724 NAME: shutdown_lifetime
4727 LOC: Config.shutdownLifetime
4730 When SIGTERM or SIGHUP is received, the cache is put into
4731 "shutdown pending" mode until all active sockets are closed.
4732 This value is the lifetime to set for all open descriptors
4733 during shutdown mode. Any active clients after this many
4734 seconds will receive a 'timeout' message.
4738 ADMINISTRATIVE PARAMETERS
4739 -----------------------------------------------------------------------------
4745 LOC: Config.adminEmail
4747 Email-address of local cache manager who will receive
4748 mail if the cache dies. The default is "webmaster."
4754 LOC: Config.EmailFrom
4756 From: email-address for mail sent when the cache dies.
4757 The default is to use 'appname@unique_hostname'.
4758 Default appname value is "squid", can be changed into
4759 src/globals.h before building squid.
4765 LOC: Config.EmailProgram
4767 Email program used to send mail if the cache dies.
4768 The default is "mail". The specified program must comply
4769 with the standard Unix mail syntax:
4770 mail-program recipient < mailfile
4772 Optional command line options can be specified.
4775 NAME: cache_effective_user
4777 DEFAULT: @DEFAULT_CACHE_EFFECTIVE_USER@
4778 LOC: Config.effectiveUser
4780 If you start Squid as root, it will change its effective/real
4781 UID/GID to the user specified below. The default is to change
4782 to UID of @DEFAULT_CACHE_EFFECTIVE_USER@.
4783 see also; cache_effective_group
4786 NAME: cache_effective_group
4789 LOC: Config.effectiveGroup
4791 Squid sets the GID to the effective user's default group ID
4792 (taken from the password file) and supplementary group list
4793 from the groups membership.
4795 If you want Squid to run with a specific GID regardless of
4796 the group memberships of the effective user then set this
4797 to the group (or GID) you want Squid to run as. When set
4798 all other group privileges of the effective user are ignored
4799 and only this GID is effective. If Squid is not started as
4800 root the user starting Squid MUST be member of the specified
4803 This option is not recommended by the Squid Team.
4804 Our preference is for administrators to configure a secure
4805 user account for squid with UID/GID matching system policies.
4808 NAME: httpd_suppress_version_string
4812 LOC: Config.onoff.httpd_suppress_version_string
4814 Suppress Squid version string info in HTTP headers and HTML error pages.
4817 NAME: visible_hostname
4819 LOC: Config.visibleHostname
4822 If you want to present a special hostname in error messages, etc,
4823 define this. Otherwise, the return value of gethostname()
4824 will be used. If you have multiple caches in a cluster and
4825 get errors about IP-forwarding you must set them to have individual
4826 names with this setting.
4829 NAME: unique_hostname
4831 LOC: Config.uniqueHostname
4834 If you want to have multiple machines with the same
4835 'visible_hostname' you must give each machine a different
4836 'unique_hostname' so forwarding loops can be detected.
4839 NAME: hostname_aliases
4841 LOC: Config.hostnameAliases
4844 A list of other DNS names your cache has.
4852 Minimum umask which should be enforced while the proxy
4853 is running, in addition to the umask set at startup.
4855 For a traditional octal representation of umasks, start
4860 OPTIONS FOR THE CACHE REGISTRATION SERVICE
4861 -----------------------------------------------------------------------------
4863 This section contains parameters for the (optional) cache
4864 announcement service. This service is provided to help
4865 cache administrators locate one another in order to join or
4866 create cache hierarchies.
4868 An 'announcement' message is sent (via UDP) to the registration
4869 service by Squid. By default, the announcement message is NOT
4870 SENT unless you enable it with 'announce_period' below.
4872 The announcement message includes your hostname, plus the
4873 following information from this configuration file:
4879 All current information is processed regularly and made
4880 available on the Web at http://www.ircache.net/Cache/Tracker/.
4883 NAME: announce_period
4885 LOC: Config.Announce.period
4888 This is how frequently to send cache announcements. The
4889 default is `0' which disables sending the announcement
4892 To enable announcing your cache, just set an announce period.
4895 announce_period 1 day
4900 DEFAULT: tracker.ircache.net
4901 LOC: Config.Announce.host
4907 LOC: Config.Announce.file
4913 LOC: Config.Announce.port
4915 announce_host and announce_port set the hostname and port
4916 number where the registration message will be sent.
4918 Hostname will default to 'tracker.ircache.net' and port will
4919 default default to 3131. If the 'filename' argument is given,
4920 the contents of that file will be included in the announce
4925 HTTPD-ACCELERATOR OPTIONS
4926 -----------------------------------------------------------------------------
4929 NAME: httpd_accel_surrogate_id
4932 LOC: Config.Accel.surrogate_id
4934 Surrogates (http://www.esi.org/architecture_spec_1.0.html)
4935 need an identification token to allow control targeting. Because
4936 a farm of surrogates may all perform the same tasks, they may share
4937 an identification token.
4939 The default ID is the visible_hostname
4942 NAME: http_accel_surrogate_remote
4946 LOC: Config.onoff.surrogate_is_remote
4948 Remote surrogates (such as those in a CDN) honour Surrogate-Control: no-store-remote.
4949 Set this to on to have squid behave as a remote surrogate.
4953 IFDEF: USE_SQUID_ESI
4954 COMMENT: libxml2|expat|custom
4956 LOC: ESIParser::Type
4959 ESI markup is not strictly XML compatible. The custom ESI parser
4960 will give higher performance, but cannot handle non ASCII character
4965 DELAY POOL PARAMETERS
4966 -----------------------------------------------------------------------------
4970 TYPE: delay_pool_count
4972 IFDEF: USE_DELAY_POOLS
4975 This represents the number of delay pools to be used. For example,
4976 if you have one class 2 delay pool and one class 3 delays pool, you
4977 have a total of 2 delay pools.
4981 TYPE: delay_pool_class
4983 IFDEF: USE_DELAY_POOLS
4986 This defines the class of each delay pool. There must be exactly one
4987 delay_class line for each delay pool. For example, to define two
4988 delay pools, one of class 2 and one of class 3, the settings above
4992 delay_pools 4 # 4 delay pools
4993 delay_class 1 2 # pool 1 is a class 2 pool
4994 delay_class 2 3 # pool 2 is a class 3 pool
4995 delay_class 3 4 # pool 3 is a class 4 pool
4996 delay_class 4 5 # pool 4 is a class 5 pool
4998 The delay pool classes are:
5000 class 1 Everything is limited by a single aggregate
5003 class 2 Everything is limited by a single aggregate
5004 bucket as well as an "individual" bucket chosen
5005 from bits 25 through 32 of the IPv4 address.
5007 class 3 Everything is limited by a single aggregate
5008 bucket as well as a "network" bucket chosen
5009 from bits 17 through 24 of the IP address and a
5010 "individual" bucket chosen from bits 17 through
5011 32 of the IPv4 address.
5013 class 4 Everything in a class 3 delay pool, with an
5014 additional limit on a per user basis. This
5015 only takes effect if the username is established
5016 in advance - by forcing authentication in your
5019 class 5 Requests are grouped according their tag (see
5020 external_acl's tag= reply).
5023 Each pool also requires a delay_parameters directive to configure the pool size
5024 and speed limits used whenever the pool is applied to a request. Along with
5025 a set of delay_access directives to determine when it is used.
5027 NOTE: If an IP address is a.b.c.d
5028 -> bits 25 through 32 are "d"
5029 -> bits 17 through 24 are "c"
5030 -> bits 17 through 32 are "c * 256 + d"
5032 NOTE-2: Due to the use of bitmasks in class 2,3,4 pools they only apply to
5033 IPv4 traffic. Class 1 and 5 pools may be used with IPv6 traffic.
5037 TYPE: delay_pool_access
5039 IFDEF: USE_DELAY_POOLS
5042 This is used to determine which delay pool a request falls into.
5044 delay_access is sorted per pool and the matching starts with pool 1,
5045 then pool 2, ..., and finally pool N. The first delay pool where the
5046 request is allowed is selected for the request. If it does not allow
5047 the request to any pool then the request is not delayed (default).
5049 For example, if you want some_big_clients in delay
5050 pool 1 and lotsa_little_clients in delay pool 2:
5053 delay_access 1 allow some_big_clients
5054 delay_access 1 deny all
5055 delay_access 2 allow lotsa_little_clients
5056 delay_access 2 deny all
5057 delay_access 3 allow authenticated_clients
5060 NAME: delay_parameters
5061 TYPE: delay_pool_rates
5063 IFDEF: USE_DELAY_POOLS
5066 This defines the parameters for a delay pool. Each delay pool has
5067 a number of "buckets" associated with it, as explained in the
5068 description of delay_class.
5070 For a class 1 delay pool, the syntax is:
5072 delay_parameters pool aggregate
5074 For a class 2 delay pool:
5076 delay_parameters pool aggregate individual
5078 For a class 3 delay pool:
5080 delay_parameters pool aggregate network individual
5082 For a class 4 delay pool:
5084 delay_parameters pool aggregate network individual user
5086 For a class 5 delay pool:
5088 delay_parameters pool tagrate
5090 The option variables are:
5092 pool a pool number - ie, a number between 1 and the
5093 number specified in delay_pools as used in
5096 aggregate the speed limit parameters for the aggregate bucket
5099 individual the speed limit parameters for the individual
5100 buckets (class 2, 3).
5102 network the speed limit parameters for the network buckets
5105 user the speed limit parameters for the user buckets
5108 tagrate the speed limit parameters for the tag buckets
5111 A pair of delay parameters is written restore/maximum, where restore is
5112 the number of bytes (not bits - modem and network speeds are usually
5113 quoted in bits) per second placed into the bucket, and maximum is the
5114 maximum number of bytes which can be in the bucket at any time.
5116 There must be one delay_parameters line for each delay pool.
5119 For example, if delay pool number 1 is a class 2 delay pool as in the
5120 above example, and is being used to strictly limit each host to 64Kbit/sec
5121 (plus overheads), with no overall limit, the line is:
5123 delay_parameters 1 -1/-1 8000/8000
5125 Note that 8 x 8000 KByte/sec -> 64Kbit/sec.
5127 Note that the figure -1 is used to represent "unlimited".
5130 And, if delay pool number 2 is a class 3 delay pool as in the above
5131 example, and you want to limit it to a total of 256Kbit/sec (strict limit)
5132 with each 8-bit network permitted 64Kbit/sec (strict limit) and each
5133 individual host permitted 4800bit/sec with a bucket maximum size of 64Kbits
5134 to permit a decent web page to be downloaded at a decent speed
5135 (if the network is not being limited due to overuse) but slow down
5136 large downloads more significantly:
5138 delay_parameters 2 32000/32000 8000/8000 600/8000
5140 Note that 8 x 32000 KByte/sec -> 256Kbit/sec.
5141 8 x 8000 KByte/sec -> 64Kbit/sec.
5142 8 x 600 Byte/sec -> 4800bit/sec.
5145 Finally, for a class 4 delay pool as in the example - each user will
5146 be limited to 128Kbits/sec no matter how many workstations they are logged into.:
5148 delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000
5151 NAME: delay_initial_bucket_level
5152 COMMENT: (percent, 0-100)
5155 IFDEF: USE_DELAY_POOLS
5156 LOC: Config.Delay.initial
5158 The initial bucket percentage is used to determine how much is put
5159 in each bucket when squid starts, is reconfigured, or first notices
5160 a host accessing it (in class 2 and class 3, individual hosts and
5161 networks only have buckets associated with them once they have been
5166 CLIENT DELAY POOL PARAMETERS
5167 -----------------------------------------------------------------------------
5170 NAME: client_delay_pools
5171 TYPE: client_delay_pool_count
5173 IFDEF: USE_DELAY_POOLS
5174 LOC: Config.ClientDelay
5176 This option specifies the number of client delay pools used. It must
5177 preceed other client_delay_* options.
5180 client_delay_pools 2
5183 NAME: client_delay_initial_bucket_level
5184 COMMENT: (percent, 0-no_limit)
5187 IFDEF: USE_DELAY_POOLS
5188 LOC: Config.ClientDelay.initial
5190 This option determines the initial bucket size as a percentage of
5191 max_bucket_size from client_delay_parameters. Buckets are created
5192 at the time of the "first" connection from the matching IP. Idle
5193 buckets are periodically deleted up.
5195 You can specify more than 100 percent but note that such "oversized"
5196 buckets are not refilled until their size goes down to max_bucket_size
5197 from client_delay_parameters.
5200 client_delay_initial_bucket_level 50
5203 NAME: client_delay_parameters
5204 TYPE: client_delay_pool_rates
5206 IFDEF: USE_DELAY_POOLS
5207 LOC: Config.ClientDelay
5210 This option configures client-side bandwidth limits using the
5213 client_delay_parameters pool speed_limit max_bucket_size
5215 pool is an integer ID used for client_delay_access matching.
5217 speed_limit is bytes added to the bucket per second.
5219 max_bucket_size is the maximum size of a bucket, enforced after any
5220 speed_limit additions.
5222 Please see the delay_parameters option for more information and
5226 client_delay_parameters 1 1024 2048
5227 client_delay_parameters 2 51200 16384
5230 NAME: client_delay_access
5231 TYPE: client_delay_pool_access
5233 IFDEF: USE_DELAY_POOLS
5234 LOC: Config.ClientDelay
5237 This option determines the client-side delay pool for the
5240 client_delay_access pool_ID allow|deny acl_name
5242 All client_delay_access options are checked in their pool ID
5243 order, starting with pool 1. The first checked pool with allowed
5244 request is selected for the request. If no ACL matches or there
5245 are no client_delay_access options, the request bandwidth is not
5248 The ACL-selected pool is then used to find the
5249 client_delay_parameters for the request. Client-side pools are
5250 not used to aggregate clients. Clients are always aggregated
5251 based on their source IP addresses (one bucket per source IP).
5253 Please see delay_access for more examples.
5256 client_delay_access 1 allow low_rate_network
5257 client_delay_access 2 allow vips_network
5261 WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS
5262 -----------------------------------------------------------------------------
5267 LOC: Config.Wccp.router
5271 Use this option to define your WCCP ``home'' router for
5274 wccp_router supports a single WCCP(v1) router
5276 wccp2_router supports multiple WCCPv2 routers
5278 only one of the two may be used at the same time and defines
5279 which version of WCCP to use.
5283 TYPE: IpAddress_list
5284 LOC: Config.Wccp2.router
5288 Use this option to define your WCCP ``home'' router for
5291 wccp_router supports a single WCCP(v1) router
5293 wccp2_router supports multiple WCCPv2 routers
5295 only one of the two may be used at the same time and defines
5296 which version of WCCP to use.
5301 LOC: Config.Wccp.version
5305 This directive is only relevant if you need to set up WCCP(v1)
5306 to some very old and end-of-life Cisco routers. In all other
5307 setups it must be left unset or at the default setting.
5308 It defines an internal version in the WCCP(v1) protocol,
5309 with version 4 being the officially documented protocol.
5311 According to some users, Cisco IOS 11.2 and earlier only
5312 support WCCP version 3. If you're using that or an earlier
5313 version of IOS, you may need to change this value to 3, otherwise
5314 do not specify this parameter.
5317 NAME: wccp2_rebuild_wait
5319 LOC: Config.Wccp2.rebuildwait
5323 If this is enabled Squid will wait for the cache dir rebuild to finish
5324 before sending the first wccp2 HereIAm packet
5327 NAME: wccp2_forwarding_method
5329 LOC: Config.Wccp2.forwarding_method
5333 WCCP2 allows the setting of forwarding methods between the
5334 router/switch and the cache. Valid values are as follows:
5336 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
5337 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
5339 Currently (as of IOS 12.4) cisco routers only support GRE.
5340 Cisco switches only support the L2 redirect assignment method.
5343 NAME: wccp2_return_method
5345 LOC: Config.Wccp2.return_method
5349 WCCP2 allows the setting of return methods between the
5350 router/switch and the cache for packets that the cache
5351 decides not to handle. Valid values are as follows:
5353 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
5354 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
5356 Currently (as of IOS 12.4) cisco routers only support GRE.
5357 Cisco switches only support the L2 redirect assignment.
5359 If the "ip wccp redirect exclude in" command has been
5360 enabled on the cache interface, then it is still safe for
5361 the proxy server to use a l2 redirect method even if this
5362 option is set to GRE.
5365 NAME: wccp2_assignment_method
5367 LOC: Config.Wccp2.assignment_method
5371 WCCP2 allows the setting of methods to assign the WCCP hash
5372 Valid values are as follows:
5374 hash - Hash assignment
5375 mask - Mask assignment
5377 As a general rule, cisco routers support the hash assignment method
5378 and cisco switches support the mask assignment method.
5383 LOC: Config.Wccp2.info
5384 DEFAULT_IF_NONE: standard 0
5387 WCCP2 allows for multiple traffic services. There are two
5388 types: "standard" and "dynamic". The standard type defines
5389 one service id - http (id 0). The dynamic service ids can be from
5390 51 to 255 inclusive. In order to use a dynamic service id
5391 one must define the type of traffic to be redirected; this is done
5392 using the wccp2_service_info option.
5394 The "standard" type does not require a wccp2_service_info option,
5395 just specifying the service id will suffice.
5397 MD5 service authentication can be enabled by adding
5398 "password=<password>" to the end of this service declaration.
5402 wccp2_service standard 0 # for the 'web-cache' standard service
5403 wccp2_service dynamic 80 # a dynamic service type which will be
5404 # fleshed out with subsequent options.
5405 wccp2_service standard 0 password=foo
5408 NAME: wccp2_service_info
5409 TYPE: wccp2_service_info
5410 LOC: Config.Wccp2.info
5414 Dynamic WCCPv2 services require further information to define the
5415 traffic you wish to have diverted.
5419 wccp2_service_info <id> protocol=<protocol> flags=<flag>,<flag>..
5420 priority=<priority> ports=<port>,<port>..
5422 The relevant WCCPv2 flags:
5423 + src_ip_hash, dst_ip_hash
5424 + source_port_hash, dst_port_hash
5425 + src_ip_alt_hash, dst_ip_alt_hash
5426 + src_port_alt_hash, dst_port_alt_hash
5429 The port list can be one to eight entries.
5433 wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source
5434 priority=240 ports=80
5436 Note: the service id must have been defined by a previous
5437 'wccp2_service dynamic <id>' entry.
5442 LOC: Config.Wccp2.weight
5446 Each cache server gets assigned a set of the destination
5447 hash proportional to their weight.
5452 LOC: Config.Wccp.address
5459 LOC: Config.Wccp2.address
5463 Use this option if you require WCCP to use a specific
5466 The default behavior is to not bind to any specific address.
5470 PERSISTENT CONNECTION HANDLING
5471 -----------------------------------------------------------------------------
5473 Also see "pconn_timeout" in the TIMEOUTS section
5476 NAME: client_persistent_connections
5478 LOC: Config.onoff.client_pconns
5482 NAME: server_persistent_connections
5484 LOC: Config.onoff.server_pconns
5487 Persistent connection support for clients and servers. By
5488 default, Squid uses persistent connections (when allowed)
5489 with its clients and servers. You can use these options to
5490 disable persistent connections with clients and/or servers.
5493 NAME: persistent_connection_after_error
5495 LOC: Config.onoff.error_pconns
5498 With this directive the use of persistent connections after
5499 HTTP errors can be disabled. Useful if you have clients
5500 who fail to handle errors on persistent connections proper.
5503 NAME: detect_broken_pconn
5505 LOC: Config.onoff.detect_broken_server_pconns
5508 Some servers have been found to incorrectly signal the use
5509 of HTTP/1.0 persistent connections even on replies not
5510 compatible, causing significant delays. This server problem
5511 has mostly been seen on redirects.
5513 By enabling this directive Squid attempts to detect such
5514 broken replies and automatically assume the reply is finished
5515 after 10 seconds timeout.
5519 CACHE DIGEST OPTIONS
5520 -----------------------------------------------------------------------------
5523 NAME: digest_generation
5524 IFDEF: USE_CACHE_DIGESTS
5526 LOC: Config.onoff.digest_generation
5529 This controls whether the server will generate a Cache Digest
5530 of its contents. By default, Cache Digest generation is
5531 enabled if Squid is compiled with --enable-cache-digests defined.
5534 NAME: digest_bits_per_entry
5535 IFDEF: USE_CACHE_DIGESTS
5537 LOC: Config.digest.bits_per_entry
5540 This is the number of bits of the server's Cache Digest which
5541 will be associated with the Digest entry for a given HTTP
5542 Method and URL (public key) combination. The default is 5.
5545 NAME: digest_rebuild_period
5546 IFDEF: USE_CACHE_DIGESTS
5549 LOC: Config.digest.rebuild_period
5552 This is the wait time between Cache Digest rebuilds.
5555 NAME: digest_rewrite_period
5557 IFDEF: USE_CACHE_DIGESTS
5559 LOC: Config.digest.rewrite_period
5562 This is the wait time between Cache Digest writes to
5566 NAME: digest_swapout_chunk_size
5569 IFDEF: USE_CACHE_DIGESTS
5570 LOC: Config.digest.swapout_chunk_size
5573 This is the number of bytes of the Cache Digest to write to
5574 disk at a time. It defaults to 4096 bytes (4KB), the Squid
5578 NAME: digest_rebuild_chunk_percentage
5579 COMMENT: (percent, 0-100)
5580 IFDEF: USE_CACHE_DIGESTS
5582 LOC: Config.digest.rebuild_chunk_percentage
5585 This is the percentage of the Cache Digest to be scanned at a
5586 time. By default it is set to 10% of the Cache Digest.
5591 -----------------------------------------------------------------------------
5596 LOC: Config.Port.snmp
5600 The port number where Squid listens for SNMP requests. To enable
5601 SNMP support set this to a suitable port number. Port number
5602 3401 is often used for the Squid SNMP agent. By default it's
5603 set to "0" (disabled)
5611 LOC: Config.accessList.snmp
5612 DEFAULT_IF_NONE: deny all
5615 Allowing or denying access to the SNMP port.
5617 All access to the agent is denied by default.
5620 snmp_access allow|deny [!]aclname ...
5622 This clause only supports fast acl types.
5623 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5625 snmp_access allow snmppublic localhost
5626 snmp_access deny all
5629 NAME: snmp_incoming_address
5631 LOC: Config.Addrs.snmp_incoming
5636 NAME: snmp_outgoing_address
5638 LOC: Config.Addrs.snmp_outgoing
5642 Just like 'udp_incoming_address', but for the SNMP port.
5644 snmp_incoming_address is used for the SNMP socket receiving
5645 messages from SNMP agents.
5646 snmp_outgoing_address is used for SNMP packets returned to SNMP
5649 The default snmp_incoming_address is to listen on all
5650 available network interfaces.
5652 If snmp_outgoing_address is not set it will use the same socket
5653 as snmp_incoming_address. Only change this if you want to have
5654 SNMP replies sent using another address than where this Squid
5655 listens for SNMP queries.
5657 NOTE, snmp_incoming_address and snmp_outgoing_address can not have
5658 the same value since they both use port 3401.
5663 -----------------------------------------------------------------------------
5666 NAME: icp_port udp_port
5669 LOC: Config.Port.icp
5671 The port number where Squid sends and receives ICP queries to
5672 and from neighbor caches. The standard UDP port for ICP is 3130.
5673 Default is disabled (0).
5676 icp_port @DEFAULT_ICP_PORT@
5683 LOC: Config.Port.htcp
5685 The port number where Squid sends and receives HTCP queries to
5686 and from neighbor caches. To turn it on you want to set it to
5687 4827. By default it is set to "0" (disabled).
5693 NAME: log_icp_queries
5697 LOC: Config.onoff.log_udp
5699 If set, ICP queries are logged to access.log. You may wish
5700 do disable this if your ICP load is VERY high to speed things
5701 up or to simplify log analysis.
5704 NAME: udp_incoming_address
5706 LOC:Config.Addrs.udp_incoming
5709 udp_incoming_address is used for UDP packets received from other
5712 The default behavior is to not bind to any specific address.
5714 Only change this if you want to have all UDP queries received on
5715 a specific interface/address.
5717 NOTE: udp_incoming_address is used by the ICP, HTCP, and DNS
5718 modules. Altering it will affect all of them in the same manner.
5720 see also; udp_outgoing_address
5722 NOTE, udp_incoming_address and udp_outgoing_address can not
5723 have the same value since they both use the same port.
5726 NAME: udp_outgoing_address
5728 LOC: Config.Addrs.udp_outgoing
5731 udp_outgoing_address is used for UDP packets sent out to other
5734 The default behavior is to not bind to any specific address.
5736 Instead it will use the same socket as udp_incoming_address.
5737 Only change this if you want to have UDP queries sent using another
5738 address than where this Squid listens for UDP queries from other
5741 NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS
5742 modules. Altering it will affect all of them in the same manner.
5744 see also; udp_incoming_address
5746 NOTE, udp_incoming_address and udp_outgoing_address can not
5747 have the same value since they both use the same port.
5754 LOC: Config.onoff.icp_hit_stale
5756 If you want to return ICP_HIT for stale cache objects, set this
5757 option to 'on'. If you have sibling relationships with caches
5758 in other administrative domains, this should be 'off'. If you only
5759 have sibling relationships with caches under your control,
5760 it is probably okay to set this to 'on'.
5761 If set to 'on', your siblings should use the option "allow-miss"
5762 on their cache_peer lines for connecting to you.
5765 NAME: minimum_direct_hops
5768 LOC: Config.minDirectHops
5770 If using the ICMP pinging stuff, do direct fetches for sites
5771 which are no more than this many hops away.
5774 NAME: minimum_direct_rtt
5777 LOC: Config.minDirectRtt
5779 If using the ICMP pinging stuff, do direct fetches for sites
5780 which are no more than this many rtt milliseconds away.
5786 LOC: Config.Netdb.low
5792 LOC: Config.Netdb.high
5794 The low and high water marks for the ICMP measurement
5795 database. These are counts, not percents. The defaults are
5796 900 and 1000. When the high water mark is reached, database
5797 entries will be deleted until the low mark is reached.
5800 NAME: netdb_ping_period
5802 LOC: Config.Netdb.period
5805 The minimum period for measuring a site. There will be at
5806 least this much delay between successive pings to the same
5807 network. The default is five minutes.
5814 LOC: Config.onoff.query_icmp
5816 If you want to ask your peers to include ICMP data in their ICP
5817 replies, enable this option.
5819 If your peer has configured Squid (during compilation) with
5820 '--enable-icmp' that peer will send ICMP pings to origin server
5821 sites of the URLs it receives. If you enable this option the
5822 ICP replies from that peer will include the ICMP data (if available).
5823 Then, when choosing a parent cache, Squid will choose the parent with
5824 the minimal RTT to the origin server. When this happens, the
5825 hierarchy field of the access.log will be
5826 "CLOSEST_PARENT_MISS". This option is off by default.
5829 NAME: test_reachability
5833 LOC: Config.onoff.test_reachability
5835 When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
5836 instead of ICP_MISS if the target host is NOT in the ICMP
5837 database, or has a zero RTT.
5840 NAME: icp_query_timeout
5844 LOC: Config.Timeout.icp_query
5846 Normally Squid will automatically determine an optimal ICP
5847 query timeout value based on the round-trip-time of recent ICP
5848 queries. If you want to override the value determined by
5849 Squid, set this 'icp_query_timeout' to a non-zero value. This
5850 value is specified in MILLISECONDS, so, to use a 2-second
5851 timeout (the old default), you would write:
5853 icp_query_timeout 2000
5856 NAME: maximum_icp_query_timeout
5860 LOC: Config.Timeout.icp_query_max
5862 Normally the ICP query timeout is determined dynamically. But
5863 sometimes it can lead to very large values (say 5 seconds).
5864 Use this option to put an upper limit on the dynamic timeout
5865 value. Do NOT use this option to always use a fixed (instead
5866 of a dynamic) timeout value. To set a fixed timeout see the
5867 'icp_query_timeout' directive.
5870 NAME: minimum_icp_query_timeout
5874 LOC: Config.Timeout.icp_query_min
5876 Normally the ICP query timeout is determined dynamically. But
5877 sometimes it can lead to very small timeouts, even lower than
5878 the normal latency variance on your link due to traffic.
5879 Use this option to put an lower limit on the dynamic timeout
5880 value. Do NOT use this option to always use a fixed (instead
5881 of a dynamic) timeout value. To set a fixed timeout see the
5882 'icp_query_timeout' directive.
5885 NAME: background_ping_rate
5889 LOC: Config.backgroundPingRate
5891 Controls how often the ICP pings are sent to siblings that
5892 have background-ping set.
5896 MULTICAST ICP OPTIONS
5897 -----------------------------------------------------------------------------
5902 LOC: Config.mcast_group_list
5905 This tag specifies a list of multicast groups which your server
5906 should join to receive multicasted ICP queries.
5908 NOTE! Be very careful what you put here! Be sure you
5909 understand the difference between an ICP _query_ and an ICP
5910 _reply_. This option is to be set only if you want to RECEIVE
5911 multicast queries. Do NOT set this option to SEND multicast
5912 ICP (use cache_peer for that). ICP replies are always sent via
5913 unicast, so this option does not affect whether or not you will
5914 receive replies from multicast group members.
5916 You must be very careful to NOT use a multicast address which
5917 is already in use by another group of caches.
5919 If you are unsure about multicast, please read the Multicast
5920 chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
5922 Usage: mcast_groups 239.128.16.128 224.0.1.20
5924 By default, Squid doesn't listen on any multicast groups.
5927 NAME: mcast_miss_addr
5928 IFDEF: MULTICAST_MISS_STREAM
5930 LOC: Config.mcast_miss.addr
5933 If you enable this option, every "cache miss" URL will
5934 be sent out on the specified multicast address.
5936 Do not enable this option unless you are are absolutely
5937 certain you understand what you are doing.
5940 NAME: mcast_miss_ttl
5941 IFDEF: MULTICAST_MISS_STREAM
5943 LOC: Config.mcast_miss.ttl
5946 This is the time-to-live value for packets multicasted
5947 when multicasting off cache miss URLs is enabled. By
5948 default this is set to 'site scope', i.e. 16.
5951 NAME: mcast_miss_port
5952 IFDEF: MULTICAST_MISS_STREAM
5954 LOC: Config.mcast_miss.port
5957 This is the port number to be used in conjunction with
5961 NAME: mcast_miss_encode_key
5962 IFDEF: MULTICAST_MISS_STREAM
5964 LOC: Config.mcast_miss.encode_key
5965 DEFAULT: XXXXXXXXXXXXXXXX
5967 The URLs that are sent in the multicast miss stream are
5968 encrypted. This is the encryption key.
5971 NAME: mcast_icp_query_timeout
5975 LOC: Config.Timeout.mcast_icp_query
5977 For multicast peers, Squid regularly sends out ICP "probes" to
5978 count how many other peers are listening on the given multicast
5979 address. This value specifies how long Squid should wait to
5980 count all the replies. The default is 2000 msec, or 2
5985 INTERNAL ICON OPTIONS
5986 -----------------------------------------------------------------------------
5989 NAME: icon_directory
5991 LOC: Config.icons.directory
5992 DEFAULT: @DEFAULT_ICON_DIR@
5994 Where the icons are stored. These are normally kept in
5998 NAME: global_internal_static
6000 LOC: Config.onoff.global_internal_static
6003 This directive controls is Squid should intercept all requests for
6004 /squid-internal-static/ no matter which host the URL is requesting
6005 (default on setting), or if nothing special should be done for
6006 such URLs (off setting). The purpose of this directive is to make
6007 icons etc work better in complex cache hierarchies where it may
6008 not always be possible for all corners in the cache mesh to reach
6009 the server generating a directory listing.
6012 NAME: short_icon_urls
6014 LOC: Config.icons.use_short_names
6017 If this is enabled Squid will use short URLs for icons.
6018 If disabled it will revert to the old behavior of including
6019 it's own name and port in the URL.
6021 If you run a complex cache hierarchy with a mix of Squid and
6022 other proxies you may need to disable this directive.
6027 -----------------------------------------------------------------------------
6030 NAME: error_directory
6032 LOC: Config.errorDirectory
6035 If you wish to create your own versions of the default
6036 error files to customize them to suit your company copy
6037 the error/template files to another directory and point
6040 WARNING: This option will disable multi-language support
6041 on error pages if used.
6043 The squid developers are interested in making squid available in
6044 a wide variety of languages. If you are making translations for a
6045 language that Squid does not currently provide please consider
6046 contributing your translation back to the project.
6047 http://wiki.squid-cache.org/Translations
6049 The squid developers working on translations are happy to supply drop-in
6050 translated error files in exchange for any new language contributions.
6053 NAME: error_default_language
6054 IFDEF: USE_ERR_LOCALES
6056 LOC: Config.errorDefaultLanguage
6059 Set the default language which squid will send error pages in
6060 if no existing translation matches the clients language
6063 If unset (default) generic English will be used.
6065 The squid developers are interested in making squid available in
6066 a wide variety of languages. If you are interested in making
6067 translations for any language see the squid wiki for details.
6068 http://wiki.squid-cache.org/Translations
6071 NAME: error_log_languages
6072 IFDEF: USE_ERR_LOCALES
6074 LOC: Config.errorLogMissingLanguages
6077 Log to cache.log what languages users are attempting to
6078 auto-negotiate for translations.
6080 Successful negotiations are not logged. Only failures
6081 have meaning to indicate that Squid may need an upgrade
6082 of its error page translations.
6085 NAME: err_page_stylesheet
6087 LOC: Config.errorStylesheet
6088 DEFAULT: @DEFAULT_CONFIG_DIR@/errorpage.css
6090 CSS Stylesheet to pattern the display of Squid default error pages.
6092 For information on CSS see http://www.w3.org/Style/CSS/
6097 LOC: Config.errHtmlText
6100 HTML text to include in error messages. Make this a "mailto"
6101 URL to your admin address, or maybe just a link to your
6102 organizations Web page.
6104 To include this in your error messages, you must rewrite
6105 the error template files (found in the "errors" directory).
6106 Wherever you want the 'err_html_text' line to appear,
6107 insert a %L tag in the error template file.
6110 NAME: email_err_data
6113 LOC: Config.onoff.emailErrData
6116 If enabled, information about the occurred error will be
6117 included in the mailto links of the ERR pages (if %W is set)
6118 so that the email body contains the data.
6119 Syntax is <A HREF="mailto:%w%W">%w</A>
6124 LOC: Config.denyInfoList
6127 Usage: deny_info err_page_name acl
6128 or deny_info http://... acl
6129 or deny_info TCP_RESET acl
6131 This can be used to return a ERR_ page for requests which
6132 do not pass the 'http_access' rules. Squid remembers the last
6133 acl it evaluated in http_access, and if a 'deny_info' line exists
6134 for that ACL Squid returns a corresponding error page.
6136 The acl is typically the last acl on the http_access deny line which
6137 denied access. The exceptions to this rule are:
6138 - When Squid needs to request authentication credentials. It's then
6139 the first authentication related acl encountered
6140 - When none of the http_access lines matches. It's then the last
6141 acl processed on the last http_access line.
6142 - When the decision to deny access was made by an adaptation service,
6143 the acl name is the corresponding eCAP or ICAP service_name.
6145 NP: If providing your own custom error pages with error_directory
6146 you may also specify them by your custom file name:
6147 Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
6149 By defaut Squid will send "403 Forbidden". A different 4xx or 5xx
6150 may be specified by prefixing the file name with the code and a colon.
6151 e.g. 404:ERR_CUSTOM_ACCESS_DENIED
6153 Alternatively you can tell Squid to reset the TCP connection
6154 by specifying TCP_RESET.
6156 Or you can specify an error URL or URL pattern. The browsers will
6157 get redirected to the specified URL after formatting tags have
6158 been replaced. Redirect will be done with 302 or 307 according to
6159 HTTP/1.1 specs. A different 3xx code may be specified by prefixing
6160 the URL. e.g. 303:http://example.com/
6163 %a - username (if available. Password NOT included)
6166 %E - Error description
6168 %H - Request domain name
6169 %i - Client IP Address
6171 %o - Message result from external ACL helper
6172 %p - Request Port number
6173 %P - Request Protocol name
6174 %R - Request URL path
6175 %T - Timestamp in RFC 1123 format
6176 %U - Full canonical URL from client
6177 (HTTPS URLs terminate with *)
6178 %u - Full canonical URL from client
6179 %w - Admin email from squid.conf
6181 %% - Literal percent (%) code
6186 OPTIONS INFLUENCING REQUEST FORWARDING
6187 -----------------------------------------------------------------------------
6190 NAME: nonhierarchical_direct
6192 LOC: Config.onoff.nonhierarchical_direct
6195 By default, Squid will send any non-hierarchical requests
6196 (matching hierarchy_stoplist or not cacheable request type) direct
6199 If you set this to off, Squid will prefer to send these
6200 requests to parents.
6202 Note that in most configurations, by turning this off you will only
6203 add latency to these request without any improvement in global hit
6206 If you are inside an firewall see never_direct instead of
6212 LOC: Config.onoff.prefer_direct
6215 Normally Squid tries to use parents for most requests. If you for some
6216 reason like it to first try going direct and only use a parent if
6217 going direct fails set this to on.
6219 By combining nonhierarchical_direct off and prefer_direct on you
6220 can set up Squid to use a parent as a backup path if going direct
6223 Note: If you want Squid to use parents for all requests see
6224 the never_direct directive. prefer_direct only modifies how Squid
6225 acts on cacheable requests.
6230 LOC: Config.accessList.AlwaysDirect
6233 Usage: always_direct allow|deny [!]aclname ...
6235 Here you can use ACL elements to specify requests which should
6236 ALWAYS be forwarded by Squid to the origin servers without using
6237 any peers. For example, to always directly forward requests for
6238 local servers ignoring any parents or siblings you may have use
6241 acl local-servers dstdomain my.domain.net
6242 always_direct allow local-servers
6244 To always forward FTP requests directly, use
6247 always_direct allow FTP
6249 NOTE: There is a similar, but opposite option named
6250 'never_direct'. You need to be aware that "always_direct deny
6251 foo" is NOT the same thing as "never_direct allow foo". You
6252 may need to use a deny rule to exclude a more-specific case of
6253 some other rule. Example:
6255 acl local-external dstdomain external.foo.net
6256 acl local-servers dstdomain .foo.net
6257 always_direct deny local-external
6258 always_direct allow local-servers
6260 NOTE: If your goal is to make the client forward the request
6261 directly to the origin server bypassing Squid then this needs
6262 to be done in the client configuration. Squid configuration
6263 can only tell Squid how Squid should fetch the object.
6265 NOTE: This directive is not related to caching. The replies
6266 is cached as usual even if you use always_direct. To not cache
6267 the replies see the 'cache' directive.
6269 This clause supports both fast and slow acl types.
6270 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6275 LOC: Config.accessList.NeverDirect
6278 Usage: never_direct allow|deny [!]aclname ...
6280 never_direct is the opposite of always_direct. Please read
6281 the description for always_direct if you have not already.
6283 With 'never_direct' you can use ACL elements to specify
6284 requests which should NEVER be forwarded directly to origin
6285 servers. For example, to force the use of a proxy for all
6286 requests, except those in your local domain use something like:
6288 acl local-servers dstdomain .foo.net
6289 never_direct deny local-servers
6290 never_direct allow all
6292 or if Squid is inside a firewall and there are local intranet
6293 servers inside the firewall use something like:
6295 acl local-intranet dstdomain .foo.net
6296 acl local-external dstdomain external.foo.net
6297 always_direct deny local-external
6298 always_direct allow local-intranet
6299 never_direct allow all
6301 This clause supports both fast and slow acl types.
6302 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6306 ADVANCED NETWORKING OPTIONS
6307 -----------------------------------------------------------------------------
6310 NAME: incoming_icp_average
6313 LOC: Config.comm_incoming.icp_average
6316 NAME: incoming_http_average
6319 LOC: Config.comm_incoming.http_average
6322 NAME: incoming_dns_average
6325 LOC: Config.comm_incoming.dns_average
6328 NAME: min_icp_poll_cnt
6331 LOC: Config.comm_incoming.icp_min_poll
6334 NAME: min_dns_poll_cnt
6337 LOC: Config.comm_incoming.dns_min_poll
6340 NAME: min_http_poll_cnt
6343 LOC: Config.comm_incoming.http_min_poll
6345 Heavy voodoo here. I can't even believe you are reading this.
6346 Are you crazy? Don't even think about adjusting these unless
6347 you understand the algorithms in comm_select.c first!
6353 LOC: Config.accept_filter
6357 The name of an accept(2) filter to install on Squid's
6358 listen socket(s). This feature is perhaps specific to
6359 FreeBSD and requires support in the kernel.
6361 The 'httpready' filter delays delivering new connections
6362 to Squid until a full HTTP request has been received.
6363 See the accf_http(9) man page for details.
6365 The 'dataready' filter delays delivering new connections
6366 to Squid until there is some data to process.
6367 See the accf_dataready(9) man page for details.
6371 The 'data' filter delays delivering of new connections
6372 to Squid until there is some data to process by TCP_ACCEPT_DEFER.
6373 You may optionally specify a number of seconds to wait by
6374 'data=N' where N is the number of seconds. Defaults to 30
6375 if not specified. See the tcp(7) man page for details.
6378 accept_filter httpready
6383 NAME: client_ip_max_connections
6385 LOC: Config.client_ip_max_connections
6388 Set an absolute limit on the number of connections a single
6389 client IP can use. Any more than this and Squid will begin to drop
6390 new connections from the client until it closes some links.
6392 Note that this is a global limit. It affects all HTTP, HTCP, Gopher and FTP
6393 connections from the client. For finer control use the ACL access controls.
6395 Requires client_db to be enabled (the default).
6397 WARNING: This may noticably slow down traffic received via external proxies
6398 or NAT devices and cause them to rebound error messages back to their clients.
6401 NAME: tcp_recv_bufsize
6405 LOC: Config.tcpRcvBufsz
6407 Size of receive buffer to set for TCP sockets. Probably just
6408 as easy to change your kernel's default. Set to zero to use
6409 the default buffer size.
6414 -----------------------------------------------------------------------------
6421 LOC: Adaptation::Icap::TheConfig.onoff
6424 If you want to enable the ICAP module support, set this to on.
6427 NAME: icap_connect_timeout
6430 LOC: Adaptation::Icap::TheConfig.connect_timeout_raw
6433 This parameter specifies how long to wait for the TCP connect to
6434 the requested ICAP server to complete before giving up and either
6435 terminating the HTTP transaction or bypassing the failure.
6437 The default for optional services is peer_connect_timeout.
6438 The default for essential services is connect_timeout.
6439 If this option is explicitly set, its value applies to all services.
6442 NAME: icap_io_timeout
6446 LOC: Adaptation::Icap::TheConfig.io_timeout_raw
6449 This parameter specifies how long to wait for an I/O activity on
6450 an established, active ICAP connection before giving up and
6451 either terminating the HTTP transaction or bypassing the
6454 The default is read_timeout.
6457 NAME: icap_service_failure_limit
6458 COMMENT: limit [in memory-depth time-units]
6459 TYPE: icap_service_failure_limit
6461 LOC: Adaptation::Icap::TheConfig
6464 The limit specifies the number of failures that Squid tolerates
6465 when establishing a new TCP connection with an ICAP service. If
6466 the number of failures exceeds the limit, the ICAP service is
6467 not used for new ICAP requests until it is time to refresh its
6470 A negative value disables the limit. Without the limit, an ICAP
6471 service will not be considered down due to connectivity failures
6472 between ICAP OPTIONS requests.
6474 Squid forgets ICAP service failures older than the specified
6475 value of memory-depth. The memory fading algorithm
6476 is approximate because Squid does not remember individual
6477 errors but groups them instead, splitting the option
6478 value into ten time slots of equal length.
6480 When memory-depth is 0 and by default this option has no
6481 effect on service failure expiration.
6483 Squid always forgets failures when updating service settings
6484 using an ICAP OPTIONS transaction, regardless of this option
6488 # suspend service usage after 10 failures in 5 seconds:
6489 icap_service_failure_limit 10 in 5 seconds
6492 NAME: icap_service_revival_delay
6495 LOC: Adaptation::Icap::TheConfig.service_revival_delay
6498 The delay specifies the number of seconds to wait after an ICAP
6499 OPTIONS request failure before requesting the options again. The
6500 failed ICAP service is considered "down" until fresh OPTIONS are
6503 The actual delay cannot be smaller than the hardcoded minimum
6504 delay of 30 seconds.
6507 NAME: icap_preview_enable
6511 LOC: Adaptation::Icap::TheConfig.preview_enable
6514 The ICAP Preview feature allows the ICAP server to handle the
6515 HTTP message by looking only at the beginning of the message body
6516 or even without receiving the body at all. In some environments,
6517 previews greatly speedup ICAP processing.
6519 During an ICAP OPTIONS transaction, the server may tell Squid what
6520 HTTP messages should be previewed and how big the preview should be.
6521 Squid will not use Preview if the server did not request one.
6523 To disable ICAP Preview for all ICAP services, regardless of
6524 individual ICAP server OPTIONS responses, set this option to "off".
6526 icap_preview_enable off
6529 NAME: icap_preview_size
6532 LOC: Adaptation::Icap::TheConfig.preview_size
6535 The default size of preview data to be sent to the ICAP server.
6536 -1 means no preview. This value might be overwritten on a per server
6537 basis by OPTIONS requests.
6540 NAME: icap_206_enable
6544 LOC: Adaptation::Icap::TheConfig.allow206_enable
6547 206 (Partial Content) responses is an ICAP extension that allows the
6548 ICAP agents to optionally combine adapted and original HTTP message
6549 content. The decision to combine is postponed until the end of the
6550 ICAP response. Squid supports Partial Content extension by default.
6552 Activation of the Partial Content extension is negotiated with each
6553 ICAP service during OPTIONS exchange. Most ICAP servers should handle
6554 negotation correctly even if they do not support the extension, but
6555 some might fail. To disable Partial Content support for all ICAP
6556 services and to avoid any negotiation, set this option to "off".
6562 NAME: icap_default_options_ttl
6565 LOC: Adaptation::Icap::TheConfig.default_options_ttl
6568 The default TTL value for ICAP OPTIONS responses that don't have
6569 an Options-TTL header.
6572 NAME: icap_persistent_connections
6576 LOC: Adaptation::Icap::TheConfig.reuse_connections
6579 Whether or not Squid should use persistent connections to
6583 NAME: adaptation_send_client_ip icap_send_client_ip
6585 IFDEF: USE_ADAPTATION
6587 LOC: Adaptation::Config::send_client_ip
6590 If enabled, Squid shares HTTP client IP information with adaptation
6591 services. For ICAP, Squid adds the X-Client-IP header to ICAP requests.
6592 For eCAP, Squid sets the libecap::metaClientIp transaction option.
6594 See also: adaptation_uses_indirect_client
6597 NAME: adaptation_send_username icap_send_client_username
6599 IFDEF: USE_ADAPTATION
6601 LOC: Adaptation::Config::send_username
6604 This sends authenticated HTTP client username (if available) to
6605 the adaptation service.
6607 For ICAP, the username value is encoded based on the
6608 icap_client_username_encode option and is sent using the header
6609 specified by the icap_client_username_header option.
6612 NAME: icap_client_username_header
6615 LOC: Adaptation::Icap::TheConfig.client_username_header
6616 DEFAULT: X-Client-Username
6618 ICAP request header name to use for adaptation_send_username.
6621 NAME: icap_client_username_encode
6625 LOC: Adaptation::Icap::TheConfig.client_username_encode
6628 Whether to base64 encode the authenticated client username.
6632 TYPE: icap_service_type
6634 LOC: Adaptation::Icap::TheConfig
6637 Defines a single ICAP service using the following format:
6639 icap_service id vectoring_point uri [option ...]
6642 an opaque identifier or name which is used to direct traffic to
6643 this specific service. Must be unique among all adaptation
6644 services in squid.conf.
6646 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
6647 This specifies at which point of transaction processing the
6648 ICAP service should be activated. *_postcache vectoring points
6649 are not yet supported.
6651 uri: icap://servername:port/servicepath
6652 ICAP server and service location.
6654 ICAP does not allow a single service to handle both REQMOD and RESPMOD
6655 transactions. Squid does not enforce that requirement. You can specify
6656 services with the same service_url and different vectoring_points. You
6657 can even specify multiple identical services as long as their
6658 service_names differ.
6661 Service options are separated by white space. ICAP services support
6662 the following name=value options:
6665 If set to 'on' or '1', the ICAP service is treated as
6666 optional. If the service cannot be reached or malfunctions,
6667 Squid will try to ignore any errors and process the message as
6668 if the service was not enabled. No all ICAP errors can be
6669 bypassed. If set to 0, the ICAP service is treated as
6670 essential and all ICAP errors will result in an error page
6671 returned to the HTTP client.
6673 Bypass is off by default: services are treated as essential.
6676 If set to 'on' or '1', the ICAP service is allowed to
6677 dynamically change the current message adaptation plan by
6678 returning a chain of services to be used next. The services
6679 are specified using the X-Next-Services ICAP response header
6680 value, formatted as a comma-separated list of service names.
6681 Each named service should be configured in squid.conf. Other
6682 services are ignored. An empty X-Next-Services value results
6683 in an empty plan which ends the current adaptation.
6685 Dynamic adaptation plan may cross or cover multiple supported
6686 vectoring points in their natural processing order.
6688 Routing is not allowed by default: the ICAP X-Next-Services
6689 response header is ignored.
6692 Only has effect on split-stack systems. The default on those systems
6693 is to use IPv4-only connections. When set to 'on' this option will
6694 make Squid use IPv6-only connections to contact this ICAP service.
6696 on-overload=block|bypass|wait|force
6697 If the service Max-Connections limit has been reached, do
6698 one of the following for each new ICAP transaction:
6699 * block: send an HTTP error response to the client
6700 * bypass: ignore the "over-connected" ICAP service
6701 * wait: wait (in a FIFO queue) for an ICAP connection slot
6702 * force: proceed, ignoring the Max-Connections limit
6704 In SMP mode with N workers, each worker assumes the service
6705 connection limit is Max-Connections/N, even though not all
6706 workers may use a given service.
6708 The default value is "bypass" if service is bypassable,
6709 otherwise it is set to "wait".
6713 Use the given number as the Max-Connections limit, regardless
6714 of the Max-Connections value given by the service, if any.
6716 Older icap_service format without optional named parameters is
6717 deprecated but supported for backward compatibility.
6720 icap_service svcBlocker reqmod_precache icap://icap1.mydomain.net:1344/reqmod bypass=0
6721 icap_service svcLogger reqmod_precache icap://icap2.mydomain.net:1344/respmod routing=on
6725 TYPE: icap_class_type
6730 This deprecated option was documented to define an ICAP service
6731 chain, even though it actually defined a set of similar, redundant
6732 services, and the chains were not supported.
6734 To define a set of redundant services, please use the
6735 adaptation_service_set directive. For service chains, use
6736 adaptation_service_chain.
6740 TYPE: icap_access_type
6745 This option is deprecated. Please use adaptation_access, which
6746 has the same ICAP functionality, but comes with better
6747 documentation, and eCAP support.
6752 -----------------------------------------------------------------------------
6759 LOC: Adaptation::Ecap::TheConfig.onoff
6762 Controls whether eCAP support is enabled.
6766 TYPE: ecap_service_type
6768 LOC: Adaptation::Ecap::TheConfig
6771 Defines a single eCAP service
6773 ecap_service id vectoring_point uri [option ...]
6776 an opaque identifier or name which is used to direct traffic to
6777 this specific service. Must be unique among all adaptation
6778 services in squid.conf.
6780 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
6781 This specifies at which point of transaction processing the
6782 eCAP service should be activated. *_postcache vectoring points
6783 are not yet supported.
6785 uri: ecap://vendor/service_name?custom&cgi=style¶meters=optional
6786 Squid uses the eCAP service URI to match this configuration
6787 line with one of the dynamically loaded services. Each loaded
6788 eCAP service must have a unique URI. Obtain the right URI from
6789 the service provider.
6792 Service options are separated by white space. eCAP services support
6793 the following name=value options:
6796 If set to 'on' or '1', the eCAP service is treated as optional.
6797 If the service cannot be reached or malfunctions, Squid will try
6798 to ignore any errors and process the message as if the service
6799 was not enabled. No all eCAP errors can be bypassed.
6800 If set to 'off' or '0', the eCAP service is treated as essential
6801 and all eCAP errors will result in an error page returned to the
6804 Bypass is off by default: services are treated as essential.
6807 If set to 'on' or '1', the eCAP service is allowed to
6808 dynamically change the current message adaptation plan by
6809 returning a chain of services to be used next.
6811 Dynamic adaptation plan may cross or cover multiple supported
6812 vectoring points in their natural processing order.
6814 Routing is not allowed by default.
6816 Older ecap_service format without optional named parameters is
6817 deprecated but supported for backward compatibility.
6821 ecap_service s1 reqmod_precache ecap://filters.R.us/leakDetector?on_error=block bypass=off
6822 ecap_service s2 respmod_precache ecap://filters.R.us/virusFilter config=/etc/vf.cfg bypass=on
6825 NAME: loadable_modules
6827 IFDEF: USE_LOADABLE_MODULES
6828 LOC: Config.loadable_module_names
6831 Instructs Squid to load the specified dynamic module(s) or activate
6832 preloaded module(s).
6834 loadable_modules @DEFAULT_PREFIX@/lib/MinimalAdapter.so
6838 MESSAGE ADAPTATION OPTIONS
6839 -----------------------------------------------------------------------------
6842 NAME: adaptation_service_set
6843 TYPE: adaptation_service_set_type
6844 IFDEF: USE_ADAPTATION
6849 Configures an ordered set of similar, redundant services. This is
6850 useful when hot standby or backup adaptation servers are available.
6852 adaptation_service_set set_name service_name1 service_name2 ...
6854 The named services are used in the set declaration order. The first
6855 applicable adaptation service from the set is used first. The next
6856 applicable service is tried if and only if the transaction with the
6857 previous service fails and the message waiting to be adapted is still
6860 When adaptation starts, broken services are ignored as if they were
6861 not a part of the set. A broken service is a down optional service.
6863 The services in a set must be attached to the same vectoring point
6864 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
6866 If all services in a set are optional then adaptation failures are
6867 bypassable. If all services in the set are essential, then a
6868 transaction failure with one service may still be retried using
6869 another service from the set, but when all services fail, the master
6870 transaction fails as well.
6872 A set may contain a mix of optional and essential services, but that
6873 is likely to lead to surprising results because broken services become
6874 ignored (see above), making previously bypassable failures fatal.
6875 Technically, it is the bypassability of the last failed service that
6878 See also: adaptation_access adaptation_service_chain
6881 adaptation_service_set svcBlocker urlFilterPrimary urlFilterBackup
6882 adaptation service_set svcLogger loggerLocal loggerRemote
6885 NAME: adaptation_service_chain
6886 TYPE: adaptation_service_chain_type
6887 IFDEF: USE_ADAPTATION
6892 Configures a list of complementary services that will be applied
6893 one-by-one, forming an adaptation chain or pipeline. This is useful
6894 when Squid must perform different adaptations on the same message.
6896 adaptation_service_chain chain_name service_name1 svc_name2 ...
6898 The named services are used in the chain declaration order. The first
6899 applicable adaptation service from the chain is used first. The next
6900 applicable service is applied to the successful adaptation results of
6901 the previous service in the chain.
6903 When adaptation starts, broken services are ignored as if they were
6904 not a part of the chain. A broken service is a down optional service.
6906 Request satisfaction terminates the adaptation chain because Squid
6907 does not currently allow declaration of RESPMOD services at the
6908 "reqmod_precache" vectoring point (see icap_service or ecap_service).
6910 The services in a chain must be attached to the same vectoring point
6911 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
6913 A chain may contain a mix of optional and essential services. If an
6914 essential adaptation fails (or the failure cannot be bypassed for
6915 other reasons), the master transaction fails. Otherwise, the failure
6916 is bypassed as if the failed adaptation service was not in the chain.
6918 See also: adaptation_access adaptation_service_set
6921 adaptation_service_chain svcRequest requestLogger urlFilter leakDetector
6924 NAME: adaptation_access
6925 TYPE: adaptation_access_type
6926 IFDEF: USE_ADAPTATION
6930 Sends an HTTP transaction to an ICAP or eCAP adaptation service.
6932 adaptation_access service_name allow|deny [!]aclname...
6933 adaptation_access set_name allow|deny [!]aclname...
6935 At each supported vectoring point, the adaptation_access
6936 statements are processed in the order they appear in this
6937 configuration file. Statements pointing to the following services
6938 are ignored (i.e., skipped without checking their ACL):
6940 - services serving different vectoring points
6941 - "broken-but-bypassable" services
6942 - "up" services configured to ignore such transactions
6943 (e.g., based on the ICAP Transfer-Ignore header).
6945 When a set_name is used, all services in the set are checked
6946 using the same rules, to find the first applicable one. See
6947 adaptation_service_set for details.
6949 If an access list is checked and there is a match, the
6950 processing stops: For an "allow" rule, the corresponding
6951 adaptation service is used for the transaction. For a "deny"
6952 rule, no adaptation service is activated.
6954 It is currently not possible to apply more than one adaptation
6955 service at the same vectoring point to the same HTTP transaction.
6957 See also: icap_service and ecap_service
6960 adaptation_access service_1 allow all
6963 NAME: adaptation_service_iteration_limit
6965 IFDEF: USE_ADAPTATION
6966 LOC: Adaptation::Config::service_iteration_limit
6969 Limits the number of iterations allowed when applying adaptation
6970 services to a message. If your longest adaptation set or chain
6971 may have more than 16 services, increase the limit beyond its
6972 default value of 16. If detecting infinite iteration loops sooner
6973 is critical, make the iteration limit match the actual number
6974 of services in your longest adaptation set or chain.
6976 Infinite adaptation loops are most likely with routing services.
6978 See also: icap_service routing=1
6981 NAME: adaptation_masterx_shared_names
6983 IFDEF: USE_ADAPTATION
6984 LOC: Adaptation::Config::masterx_shared_name
6987 For each master transaction (i.e., the HTTP request and response
6988 sequence, including all related ICAP and eCAP exchanges), Squid
6989 maintains a table of metadata. The table entries are (name, value)
6990 pairs shared among eCAP and ICAP exchanges. The table is destroyed
6991 with the master transaction.
6993 This option specifies the table entry names that Squid must accept
6994 from and forward to the adaptation transactions.
6996 An ICAP REQMOD or RESPMOD transaction may set an entry in the
6997 shared table by returning an ICAP header field with a name
6998 specified in adaptation_masterx_shared_names.
7000 An eCAP REQMOD or RESPMOD transaction may set an entry in the
7001 shared table by implementing the libecap::visitEachOption() API
7002 to provide an option with a name specified in
7003 adaptation_masterx_shared_names.
7005 Squid will store and forward the set entry to subsequent adaptation
7006 transactions within the same master transaction scope.
7008 Only one shared entry name is supported at this time.
7011 # share authentication information among ICAP services
7012 adaptation_masterx_shared_names X-Subscriber-ID
7015 NAME: adaptation_meta
7016 TYPE: adaptation_meta_type
7017 IFDEF: USE_ADAPTATION
7018 LOC: Adaptation::Config::metaHeaders
7021 This option allows Squid administrator to add custom ICAP request
7022 headers or eCAP options to Squid ICAP requests or eCAP transactions.
7023 Use it to pass custom authentication tokens and other
7024 transaction-state related meta information to an ICAP/eCAP service.
7026 The addition of a meta header is ACL-driven:
7027 adaptation_meta name value [!]aclname ...
7029 Processing for a given header name stops after the first ACL list match.
7030 Thus, it is impossible to add two headers with the same name. If no ACL
7031 lists match for a given header name, no such header is added. For
7034 # do not debug transactions except for those that need debugging
7035 adaptation_meta X-Debug 1 needs_debugging
7037 # log all transactions except for those that must remain secret
7038 adaptation_meta X-Log 1 !keep_secret
7040 # mark transactions from users in the "G 1" group
7041 adaptation_meta X-Authenticated-Groups "G 1" authed_as_G1
7043 The "value" parameter may be a regular squid.conf token or a "double
7044 quoted string". Within the quoted string, use backslash (\) to escape
7045 any character, which is currently only useful for escaping backslashes
7046 and double quotes. For example,
7047 "this string has one backslash (\\) and two \"quotes\""
7053 LOC: Adaptation::Icap::TheConfig.repeat
7054 DEFAULT_IF_NONE: deny all
7056 This ACL determines which retriable ICAP transactions are
7057 retried. Transactions that received a complete ICAP response
7058 and did not have to consume or produce HTTP bodies to receive
7059 that response are usually retriable.
7061 icap_retry allow|deny [!]aclname ...
7063 Squid automatically retries some ICAP I/O timeouts and errors
7064 due to persistent connection race conditions.
7066 See also: icap_retry_limit
7069 NAME: icap_retry_limit
7072 LOC: Adaptation::Icap::TheConfig.repeat_limit
7075 Limits the number of retries allowed. When set to zero (default),
7076 no retries are allowed.
7078 Communication errors due to persistent connection race
7079 conditions are unavoidable, automatically retried, and do not
7080 count against this limit.
7082 See also: icap_retry
7088 -----------------------------------------------------------------------------
7091 NAME: check_hostnames
7094 LOC: Config.onoff.check_hostnames
7096 For security and stability reasons Squid can check
7097 hostnames for Internet standard RFC compliance. If you want
7098 Squid to perform these checks turn this directive on.
7101 NAME: allow_underscore
7104 LOC: Config.onoff.allow_underscore
7106 Underscore characters is not strictly allowed in Internet hostnames
7107 but nevertheless used by many sites. Set this to off if you want
7108 Squid to be strict about the standard.
7109 This check is performed only when check_hostnames is set to on.
7112 NAME: cache_dns_program
7114 IFDEF: USE_DNSHELPER
7115 DEFAULT: @DEFAULT_DNSSERVER@
7116 LOC: Config.Program.dnsserver
7118 Specify the location of the executable for dnslookup process.
7122 TYPE: HelperChildConfig
7123 IFDEF: USE_DNSHELPER
7124 DEFAULT: 32 startup=1 idle=1
7125 LOC: Config.dnsChildren
7127 The maximum number of processes spawn to service DNS name lookups.
7128 If you limit it too few Squid will have to wait for them to process
7129 a backlog of requests, slowing it down. If you allow too many they
7130 will use RAM and other system resources noticably.
7131 The maximum this may be safely set to is 32.
7133 The startup= and idle= options allow some measure of skew in your
7138 Sets a minimum of how many processes are to be spawned when Squid
7139 starts or reconfigures. When set to zero the first request will
7140 cause spawning of the first child process to handle it.
7142 Starting too few will cause an initial slowdown in traffic as Squid
7143 attempts to simultaneously spawn enough processes to cope.
7147 Sets a minimum of how many processes Squid is to try and keep available
7148 at all times. When traffic begins to rise above what the existing
7149 processes can handle this many more will be spawned up to the maximum
7150 configured. A minimum setting of 1 is required.
7153 NAME: dns_retransmit_interval
7156 LOC: Config.Timeout.idns_retransmit
7157 IFDEF: !USE_DNSHELPER
7159 Initial retransmit interval for DNS queries. The interval is
7160 doubled each time all configured DNS servers have been tried.
7166 LOC: Config.Timeout.idns_query
7167 IFDEF: !USE_DNSHELPER
7169 DNS Query timeout. If no response is received to a DNS query
7170 within this time all DNS servers for the queried domain
7171 are assumed to be unavailable.
7174 NAME: dns_packet_max
7177 LOC: Config.dns.packet_max
7178 IFDEF: !USE_DNSHELPER
7180 Maximum number of bytes packet size to advertise via EDNS.
7181 Set to "none" to disable EDNS large packet support.
7183 For legacy reasons DNS UDP replies will default to 512 bytes which
7184 is too small for many responses. EDNS provides a means for Squid to
7185 negotiate receiving larger responses back immediately without having
7186 to failover with repeat requests. Responses larger than this limit
7187 will retain the old behaviour of failover to TCP DNS.
7189 Squid has no real fixed limit internally, but allowing packet sizes
7190 over 1500 bytes requires network jumbogram support and is usually not
7193 WARNING: The RFC also indicates that some older resolvers will reply
7194 with failure of the whole request if the extension is added. Some
7195 resolvers have already been identified which will reply with mangled
7196 EDNS response on occasion. Usually in response to many-KB jumbogram
7197 sizes being advertised by Squid.
7198 Squid will currently treat these both as an unable-to-resolve domain
7199 even if it would be resolvable without EDNS.
7206 LOC: Config.onoff.res_defnames
7208 Normally the RES_DEFNAMES resolver option is disabled
7209 (see res_init(3)). This prevents caches in a hierarchy
7210 from interpreting single-component hostnames locally. To allow
7211 Squid to handle single-component names, enable this option.
7214 NAME: dns_nameservers
7217 LOC: Config.dns_nameservers
7219 Use this if you want to specify a list of DNS name servers
7220 (IP addresses) to use instead of those given in your
7221 /etc/resolv.conf file.
7222 On Windows platforms, if no value is specified here or in
7223 the /etc/resolv.conf file, the list of DNS name servers are
7224 taken from the Windows registry, both static and dynamic DHCP
7225 configurations are supported.
7227 Example: dns_nameservers 10.0.0.1 192.172.0.4
7232 DEFAULT: @DEFAULT_HOSTS@
7233 LOC: Config.etcHostsPath
7235 Location of the host-local IP name-address associations
7236 database. Most Operating Systems have such a file on different
7238 - Un*X & Linux: /etc/hosts
7239 - Windows NT/2000: %SystemRoot%\system32\drivers\etc\hosts
7240 (%SystemRoot% value install default is c:\winnt)
7241 - Windows XP/2003: %SystemRoot%\system32\drivers\etc\hosts
7242 (%SystemRoot% value install default is c:\windows)
7243 - Windows 9x/Me: %windir%\hosts
7244 (%windir% value is usually c:\windows)
7245 - Cygwin: /etc/hosts
7247 The file contains newline-separated definitions, in the
7248 form ip_address_in_dotted_form name [name ...] names are
7249 whitespace-separated. Lines beginning with an hash (#)
7250 character are comments.
7252 The file is checked at startup and upon configuration.
7253 If set to 'none', it won't be checked.
7254 If append_domain is used, that domain will be added to
7255 domain-local (i.e. not containing any dot character) host
7261 LOC: Config.appendDomain
7264 Appends local domain name to hostnames without any dots in
7265 them. append_domain must begin with a period.
7267 Be warned there are now Internet names with no dots in
7268 them using only top-domain names, so setting this may
7269 cause some Internet sites to become unavailable.
7272 append_domain .yourdomain.com
7275 NAME: ignore_unknown_nameservers
7277 LOC: Config.onoff.ignore_unknown_nameservers
7279 IFDEF: !USE_DNSHELPER
7281 By default Squid checks that DNS responses are received
7282 from the same IP addresses they are sent to. If they
7283 don't match, Squid ignores the response and writes a warning
7284 message to cache.log. You can allow responses from unknown
7285 nameservers by setting this option to 'off'.
7291 LOC: Config.dns.v4_first
7292 IFDEF: !USE_DNSHELPER
7294 With the IPv6 Internet being as fast or faster than IPv4 Internet
7295 for most networks Squid prefers to contact websites over IPv6.
7297 This option reverses the order of preference to make Squid contact
7298 dual-stack websites over IPv4 first. Squid will still perform both
7299 IPv6 and IPv4 DNS lookups before connecting.
7302 This option will restrict the situations under which IPv6
7303 connectivity is used (and tested). Hiding network problems
7304 which would otherwise be detected and warned about.
7308 COMMENT: (number of entries)
7311 LOC: Config.ipcache.size
7318 LOC: Config.ipcache.low
7325 LOC: Config.ipcache.high
7327 The size, low-, and high-water marks for the IP cache.
7330 NAME: fqdncache_size
7331 COMMENT: (number of entries)
7334 LOC: Config.fqdncache.size
7336 Maximum number of FQDN cache entries.
7341 -----------------------------------------------------------------------------
7348 LOC: Config.onoff.mem_pools
7350 If set, Squid will keep pools of allocated (but unused) memory
7351 available for future use. If memory is a premium on your
7352 system and you believe your malloc library outperforms Squid
7353 routines, disable this.
7356 NAME: memory_pools_limit
7360 LOC: Config.MemPools.limit
7362 Used only with memory_pools on:
7363 memory_pools_limit 50 MB
7365 If set to a non-zero value, Squid will keep at most the specified
7366 limit of allocated (but unused) memory in memory pools. All free()
7367 requests that exceed this limit will be handled by your malloc
7368 library. Squid does not pre-allocate any memory, just safe-keeps
7369 objects that otherwise would be free()d. Thus, it is safe to set
7370 memory_pools_limit to a reasonably high value even if your
7371 configuration will use less memory.
7373 If set to none, Squid will keep all memory it can. That is, there
7374 will be no limit on the total amount of memory used for safe-keeping.
7376 To disable memory allocation optimization, do not set
7377 memory_pools_limit to 0 or none. Set memory_pools to "off" instead.
7379 An overhead for maintaining memory pools is not taken into account
7380 when the limit is checked. This overhead is close to four bytes per
7381 object kept. However, pools may actually _save_ memory because of
7382 reduced memory thrashing in your malloc library.
7386 COMMENT: on|off|transparent|truncate|delete
7389 LOC: opt_forwarded_for
7391 If set to "on", Squid will append your client's IP address
7392 in the HTTP requests it forwards. By default it looks like:
7394 X-Forwarded-For: 192.1.2.3
7396 If set to "off", it will appear as
7398 X-Forwarded-For: unknown
7400 If set to "transparent", Squid will not alter the
7401 X-Forwarded-For header in any way.
7403 If set to "delete", Squid will delete the entire
7404 X-Forwarded-For header.
7406 If set to "truncate", Squid will remove all existing
7407 X-Forwarded-For entries, and place the client IP as the sole entry.
7410 NAME: cachemgr_passwd
7411 TYPE: cachemgrpasswd
7413 LOC: Config.passwd_list
7415 Specify passwords for cachemgr operations.
7417 Usage: cachemgr_passwd password action action ...
7419 Some valid actions are (see cache manager menu for a full list):
7459 * Indicates actions which will not be performed without a
7460 valid password, others can be performed if not listed here.
7462 To disable an action, set the password to "disable".
7463 To allow performing an action without a password, set the
7466 Use the keyword "all" to set the same password for all actions.
7469 cachemgr_passwd secret shutdown
7470 cachemgr_passwd lesssssssecret info stats/objects
7471 cachemgr_passwd disable all
7478 LOC: Config.onoff.client_db
7480 If you want to disable collecting per-client statistics,
7481 turn off client_db here.
7484 NAME: refresh_all_ims
7488 LOC: Config.onoff.refresh_all_ims
7490 When you enable this option, squid will always check
7491 the origin server for an update when a client sends an
7492 If-Modified-Since request. Many browsers use IMS
7493 requests when the user requests a reload, and this
7494 ensures those clients receive the latest version.
7496 By default (off), squid may return a Not Modified response
7497 based on the age of the cached version.
7500 NAME: reload_into_ims
7501 IFDEF: USE_HTTP_VIOLATIONS
7505 LOC: Config.onoff.reload_into_ims
7507 When you enable this option, client no-cache or ``reload''
7508 requests will be changed to If-Modified-Since requests.
7509 Doing this VIOLATES the HTTP standard. Enabling this
7510 feature could make you liable for problems which it
7513 see also refresh_pattern for a more selective approach.
7516 NAME: connect_retries
7518 LOC: Config.connect_retries
7521 This sets the maximum number of connection attempts made for each
7522 TCP connection. The connect_retries attempts must all still
7523 complete within the connection timeout period.
7525 The default is not to re-try if the first connection attempt fails.
7526 The (not recommended) maximum is 10 tries.
7528 A warning message will be generated if it is set to a too-high
7529 value and the configured value will be over-ridden.
7531 Note: These re-tries are in addition to forward_max_tries
7532 which limit how many different addresses may be tried to find
7536 NAME: retry_on_error
7538 LOC: Config.retry.onerror
7541 If set to ON Squid will automatically retry requests when
7542 receiving an error response with status 403 (Forbidden),
7543 500 (Internal Error), 501 or 503 (Service not available).
7544 Status 502 and 504 (Gateway errors) are always retried.
7546 This is mainly useful if you are in a complex cache hierarchy to
7547 work around access control errors.
7549 NOTE: This retry will attempt to find another working destination.
7550 Which is different from the server which just failed.
7553 NAME: as_whois_server
7555 LOC: Config.as_whois_server
7556 DEFAULT: whois.ra.net
7558 WHOIS server to query for AS numbers. NOTE: AS numbers are
7559 queried only when Squid starts up, not for every request.
7564 LOC: Config.onoff.offline
7567 Enable this option and Squid will never try to validate cached
7571 NAME: uri_whitespace
7572 TYPE: uri_whitespace
7573 LOC: Config.uri_whitespace
7576 What to do with requests that have whitespace characters in the
7579 strip: The whitespace characters are stripped out of the URL.
7580 This is the behavior recommended by RFC2396.
7581 deny: The request is denied. The user receives an "Invalid
7583 allow: The request is allowed and the URI is not changed. The
7584 whitespace characters remain in the URI. Note the
7585 whitespace is passed to redirector processes if they
7587 encode: The request is allowed and the whitespace characters are
7588 encoded according to RFC1738. This could be considered
7589 a violation of the HTTP/1.1
7590 RFC because proxies are not allowed to rewrite URI's.
7591 chop: The request is allowed and the URI is chopped at the
7592 first whitespace. This might also be considered a
7598 LOC: Config.chroot_dir
7601 Specifies a directory where Squid should do a chroot() while
7602 initializing. This also causes Squid to fully drop root
7603 privileges after initializing. This means, for example, if you
7604 use a HTTP port less than 1024 and try to reconfigure, you may
7605 get an error saying that Squid can not open the port.
7608 NAME: balance_on_multiple_ip
7610 LOC: Config.onoff.balance_on_multiple_ip
7613 Modern IP resolvers in squid sort lookup results by preferred access.
7614 By default squid will use these IP in order and only rotates to
7615 the next listed when the most preffered fails.
7617 Some load balancing servers based on round robin DNS have been
7618 found not to preserve user session state across requests
7619 to different IP addresses.
7621 Enabling this directive Squid rotates IP's per request.
7624 NAME: pipeline_prefetch
7626 LOC: Config.onoff.pipeline_prefetch
7629 To boost the performance of pipelined requests to closer
7630 match that of a non-proxied environment Squid can try to fetch
7631 up to two requests in parallel from a pipeline.
7633 Defaults to off for bandwidth management and access logging
7636 WARNING: pipelining breaks NTLM and Negotiate/Kerberos authentication.
7639 NAME: high_response_time_warning
7642 LOC: Config.warnings.high_rptm
7645 If the one-minute median response time exceeds this value,
7646 Squid prints a WARNING with debug level 0 to get the
7647 administrators attention. The value is in milliseconds.
7650 NAME: high_page_fault_warning
7652 LOC: Config.warnings.high_pf
7655 If the one-minute average page fault rate exceeds this
7656 value, Squid prints a WARNING with debug level 0 to get
7657 the administrators attention. The value is in page faults
7661 NAME: high_memory_warning
7663 LOC: Config.warnings.high_memory
7666 If the memory usage (as determined by mallinfo) exceeds
7667 this amount, Squid prints a WARNING with debug level 0 to get
7668 the administrators attention.
7671 NAME: sleep_after_fork
7672 COMMENT: (microseconds)
7674 LOC: Config.sleep_after_fork
7677 When this is set to a non-zero value, the main Squid process
7678 sleeps the specified number of microseconds after a fork()
7679 system call. This sleep may help the situation where your
7680 system reports fork() failures due to lack of (virtual)
7681 memory. Note, however, if you have a lot of child
7682 processes, these sleep delays will add up and your
7683 Squid will not service requests for some amount of time
7684 until all the child processes have been started.
7685 On Windows value less then 1000 (1 milliseconds) are
7689 NAME: windows_ipaddrchangemonitor
7690 IFDEF: _SQUID_MSWIN_
7694 LOC: Config.onoff.WIN32_IpAddrChangeMonitor
7696 On Windows Squid by default will monitor IP address changes and will
7697 reconfigure itself after any detected event. This is very useful for
7698 proxies connected to internet with dial-up interfaces.
7699 In some cases (a Proxy server acting as VPN gateway is one) it could be
7700 desiderable to disable this behaviour setting this to 'off'.
7701 Note: after changing this, Squid service must be restarted.
7706 IFDEF: USE_SQUID_EUI
7708 LOC: Eui::TheConfig.euiLookup
7710 Whether to lookup the EUI or MAC address of a connected client.
7713 NAME: max_filedescriptors max_filedesc
7716 LOC: Config.max_filedescriptors
7718 The maximum number of filedescriptors supported.
7720 The default "0" means Squid inherits the current ulimit setting.
7722 Note: Changing this requires a restart of Squid. Also
7723 not all comm loops supports large values.
7731 Number of main Squid processes or "workers" to fork and maintain.
7732 0: "no daemon" mode, like running "squid -N ..."
7733 1: "no SMP" mode, start one main Squid process daemon (default)
7734 N: start N main Squid process daemons (i.e., SMP mode)
7736 In SMP mode, each worker does nearly all what a single Squid daemon
7737 does (e.g., listen on http_port and forward HTTP requests).
7740 NAME: cpu_affinity_map
7741 TYPE: CpuAffinityMap
7742 LOC: Config.cpuAffinityMap
7745 Usage: cpu_affinity_map process_numbers=P1,P2,... cores=C1,C2,...
7747 Sets 1:1 mapping between Squid processes and CPU cores. For example,
7749 cpu_affinity_map process_numbers=1,2,3,4 cores=1,3,5,7
7751 affects processes 1 through 4 only and places them on the first
7752 four even cores, starting with core #1.
7754 CPU cores are numbered starting from 1. Requires support for
7755 sched_getaffinity(2) and sched_setaffinity(2) system calls.
7757 Multiple cpu_affinity_map options are merged.
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