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
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)
1409 cipher= Colon separated list of supported ciphers.
1410 NOTE: some ciphers such as EDH ciphers depend on
1411 additional settings. If those settings are
1412 omitted the ciphers may be silently ignored
1413 by the OpenSSL library.
1415 options= Various SSL implementation options. The most important
1417 NO_SSLv2 Disallow the use of SSLv2
1418 NO_SSLv3 Disallow the use of SSLv3
1419 NO_TLSv1 Disallow the use of TLSv1.0
1420 NO_TLSv1_1 Disallow the use of TLSv1.1
1421 NO_TLSv1_2 Disallow the use of TLSv1.2
1422 SINGLE_DH_USE Always create a new key when using
1423 temporary/ephemeral DH key exchanges
1424 ALL Enable various bug workarounds
1425 suggested as "harmless" by OpenSSL
1426 Be warned that this reduces SSL/TLS
1427 strength to some attacks.
1428 See OpenSSL SSL_CTX_set_options documentation for a
1429 complete list of options.
1431 clientca= File containing the list of CAs to use when
1432 requesting a client certificate.
1434 cafile= File containing additional CA certificates to
1435 use when verifying client certificates. If unset
1436 clientca will be used.
1438 capath= Directory containing additional CA certificates
1439 and CRL lists to use when verifying client certificates.
1441 crlfile= File of additional CRL lists to use when verifying
1442 the client certificate, in addition to CRLs stored in
1443 the capath. Implies VERIFY_CRL flag below.
1445 dhparams= File containing DH parameters for temporary/ephemeral
1446 DH key exchanges. See OpenSSL documentation for details
1447 on how to create this file.
1448 WARNING: EDH ciphers will be silently disabled if this
1451 sslflags= Various flags modifying the use of SSL:
1453 Don't request client certificates
1454 immediately, but wait until acl processing
1455 requires a certificate (not yet implemented).
1457 Don't use the default CA lists built in
1460 Don't allow for session reuse. Each connection
1461 will result in a new SSL session.
1463 Verify CRL lists when accepting client
1466 Verify CRL lists for all certificates in the
1467 client certificate chain.
1469 sslcontext= SSL session ID context identifier.
1473 connection-auth[=on|off]
1474 use connection-auth=off to tell Squid to prevent
1475 forwarding Microsoft connection oriented authentication
1476 (NTLM, Negotiate and Kerberos)
1478 disable-pmtu-discovery=
1479 Control Path-MTU discovery usage:
1480 off lets OS decide on what to do (default).
1481 transparent disable PMTU discovery when transparent
1483 always disable always PMTU discovery.
1485 In many setups of transparently intercepting proxies
1486 Path-MTU discovery can not work on traffic towards the
1487 clients. This is the case when the intercepting device
1488 does not fully track connections and fails to forward
1489 ICMP must fragment messages to the cache server. If you
1490 have such setup and experience that certain clients
1491 sporadically hang or never complete requests set
1492 disable-pmtu-discovery option to 'transparent'.
1494 name= Specifies a internal name for the port. Defaults to
1495 the port specification (port or addr:port)
1497 tcpkeepalive[=idle,interval,timeout]
1498 Enable TCP keepalive probes of idle connections.
1499 In seconds; idle is the initial time before TCP starts
1500 probing the connection, interval how often to probe, and
1501 timeout the time before giving up.
1503 If you run Squid on a dual-homed machine with an internal
1504 and an external interface we recommend you to specify the
1505 internal address:port in http_port. This way Squid will only be
1506 visible on the internal address.
1510 # Squid normally listens to port 3128
1511 http_port @DEFAULT_HTTP_PORT@
1519 LOC: Config.Sockaddr.https
1521 Usage: [ip:]port cert=certificate.pem [key=key.pem] [mode] [options...]
1523 The socket address where Squid will listen for client requests made
1524 over TLS or SSL connections. Commonly referred to as HTTPS.
1526 This is most useful for situations where you are running squid in
1527 accelerator mode and you want to do the SSL work at the accelerator level.
1529 You may specify multiple socket addresses on multiple lines,
1530 each with their own SSL certificate and/or options.
1532 See http_port for a list of available options.
1535 NAME: tcp_outgoing_tos tcp_outgoing_ds tcp_outgoing_dscp
1538 LOC: Ip::Qos::TheConfig.tosToServer
1540 Allows you to select a TOS/Diffserv value for packets outgoing
1541 on the server side, based on an ACL.
1543 tcp_outgoing_tos ds-field [!]aclname ...
1545 Example where normal_service_net uses the TOS value 0x00
1546 and good_service_net uses 0x20
1548 acl normal_service_net src 10.0.0.0/24
1549 acl good_service_net src 10.0.1.0/24
1550 tcp_outgoing_tos 0x00 normal_service_net
1551 tcp_outgoing_tos 0x20 good_service_net
1553 TOS/DSCP values really only have local significance - so you should
1554 know what you're specifying. For more information, see RFC2474,
1555 RFC2475, and RFC3260.
1557 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
1558 "default" to use whatever default your host has. Note that in
1559 practice often only multiples of 4 is usable as the two rightmost bits
1560 have been redefined for use by ECN (RFC 3168 section 23.1).
1562 Processing proceeds in the order specified, and stops at first fully
1566 NAME: clientside_tos
1569 LOC: Ip::Qos::TheConfig.tosToClient
1571 Allows you to select a TOS/Diffserv value for packets being transmitted
1572 on the client-side, based on an ACL.
1574 clientside_tos ds-field [!]aclname ...
1576 Example where normal_service_net uses the TOS value 0x00
1577 and good_service_net uses 0x20
1579 acl normal_service_net src 10.0.0.0/24
1580 acl good_service_net src 10.0.1.0/24
1581 clientside_tos 0x00 normal_service_net
1582 clientside_tos 0x20 good_service_net
1584 Note: This feature is incompatible with qos_flows. Any TOS values set here
1585 will be overwritten by TOS values in qos_flows.
1588 NAME: tcp_outgoing_mark
1590 IFDEF: SO_MARK&&USE_LIBCAP
1592 LOC: Ip::Qos::TheConfig.nfmarkToServer
1594 Allows you to apply a Netfilter mark value to outgoing packets
1595 on the server side, based on an ACL.
1597 tcp_outgoing_mark mark-value [!]aclname ...
1599 Example where normal_service_net uses the mark value 0x00
1600 and good_service_net uses 0x20
1602 acl normal_service_net src 10.0.0.0/24
1603 acl good_service_net src 10.0.1.0/24
1604 tcp_outgoing_mark 0x00 normal_service_net
1605 tcp_outgoing_mark 0x20 good_service_net
1608 NAME: clientside_mark
1610 IFDEF: SO_MARK&&USE_LIBCAP
1612 LOC: Ip::Qos::TheConfig.nfmarkToClient
1614 Allows you to apply a Netfilter mark value to packets being transmitted
1615 on the client-side, based on an ACL.
1617 clientside_mark mark-value [!]aclname ...
1619 Example where normal_service_net uses the mark value 0x00
1620 and good_service_net uses 0x20
1622 acl normal_service_net src 10.0.0.0/24
1623 acl good_service_net src 10.0.1.0/24
1624 clientside_mark 0x00 normal_service_net
1625 clientside_mark 0x20 good_service_net
1627 Note: This feature is incompatible with qos_flows. Any mark values set here
1628 will be overwritten by mark values in qos_flows.
1635 LOC: Ip::Qos::TheConfig
1637 Allows you to select a TOS/DSCP value to mark outgoing
1638 connections with, based on where the reply was sourced. For
1639 platforms using netfilter, allows you to set a netfilter mark
1640 value instead of, or in addition to, a TOS value.
1642 TOS values really only have local significance - so you should
1643 know what you're specifying. For more information, see RFC2474,
1644 RFC2475, and RFC3260.
1646 The TOS/DSCP byte must be exactly that - a octet value 0 - 255. Note that
1647 in practice often only multiples of 4 is usable as the two rightmost bits
1648 have been redefined for use by ECN (RFC 3168 section 23.1).
1650 Mark values can be any unsigned 32-bit integer value.
1652 This setting is configured by setting the following values:
1654 tos|mark Whether to set TOS or netfilter mark values
1656 local-hit=0xFF Value to mark local cache hits.
1658 sibling-hit=0xFF Value to mark hits from sibling peers.
1660 parent-hit=0xFF Value to mark hits from parent peers.
1662 miss=0xFF[/mask] Value to mark cache misses. Takes precedence
1663 over the preserve-miss feature (see below), unless
1664 mask is specified, in which case only the bits
1665 specified in the mask are written.
1667 The TOS variant of the following features are only possible on Linux
1668 and require your kernel to be patched with the TOS preserving ZPH
1669 patch, available from http://zph.bratcheda.org
1670 No patch is needed to preserve the netfilter mark, which will work
1671 with all variants of netfilter.
1673 disable-preserve-miss
1674 This option disables the preservation of the TOS or netfilter
1675 mark. By default, the existing TOS or netfilter mark value of
1676 the response coming from the remote server will be retained
1677 and masked with miss-mark.
1678 NOTE: in the case of a netfilter mark, the mark must be set on
1679 the connection (using the CONNMARK target) not on the packet
1683 Allows you to mask certain bits in the TOS or mark value
1684 received from the remote server, before copying the value to
1685 the TOS sent towards clients.
1686 Default for tos: 0xFF (TOS from server is not changed).
1687 Default for mark: 0xFFFFFFFF (mark from server is not changed).
1689 All of these features require the --enable-zph-qos compilation flag
1690 (enabled by default). Netfilter marking also requires the
1691 libnetfilter_conntrack libraries (--with-netfilter-conntrack) and
1692 libcap 2.09+ (--with-libcap).
1696 NAME: tcp_outgoing_address
1699 LOC: Config.accessList.outgoing_address
1701 Allows you to map requests to different outgoing IP addresses
1702 based on the username or source address of the user making
1705 tcp_outgoing_address ipaddr [[!]aclname] ...
1708 Forwarding clients with dedicated IPs for certain subnets.
1710 acl normal_service_net src 10.0.0.0/24
1711 acl good_service_net src 10.0.2.0/24
1713 tcp_outgoing_address 2001:db8::c001 good_service_net
1714 tcp_outgoing_address 10.1.0.2 good_service_net
1716 tcp_outgoing_address 2001:db8::beef normal_service_net
1717 tcp_outgoing_address 10.1.0.1 normal_service_net
1719 tcp_outgoing_address 2001:db8::1
1720 tcp_outgoing_address 10.1.0.3
1722 Processing proceeds in the order specified, and stops at first fully
1725 Squid will add an implicit IP version test to each line.
1726 Requests going to IPv4 websites will use the outgoing 10.1.0.* addresses.
1727 Requests going to IPv6 websites will use the outgoing 2001:db8:* addresses.
1730 NOTE: The use of this directive using client dependent ACLs is
1731 incompatible with the use of server side persistent connections. To
1732 ensure correct results it is best to set server_persistent_connections
1733 to off when using this directive in such configurations.
1735 NOTE: The use of this directive to set a local IP on outgoing TCP links
1736 is incompatible with using TPROXY to set client IP out outbound TCP links.
1737 When needing to contact peers use the no-tproxy cache_peer option and the
1738 client_dst_passthru directive re-enable normal forwarding such as this.
1742 NAME: host_verify_strict
1745 LOC: Config.onoff.hostStrictVerify
1747 Regardless of this option setting, when dealing with intercepted
1748 traffic, Squid always verifies that the destination IP address matches
1749 the Host header domain or IP (called 'authority form URL').
1751 This enforcement is performed to satisfy a MUST-level requirement in
1752 RFC 2616 section 14.23: "The Host field value MUST represent the naming
1753 authority of the origin server or gateway given by the original URL".
1756 Squid always responds with an HTTP 409 (Conflict) error
1757 page and logs a security warning if there is no match.
1759 Squid verifies that the destination IP address matches
1760 the Host header for forward-proxy and reverse-proxy traffic
1761 as well. For those traffic types, Squid also enables the
1762 following checks, comparing the corresponding Host header
1763 and Request-URI components:
1765 * The host names (domain or IP) must be identical,
1766 but valueless or missing Host header disables all checks.
1767 For the two host names to match, both must be either IP
1770 * Port numbers must be identical, but if a port is missing
1771 the scheme-default port is assumed.
1774 When set to OFF (the default):
1775 Squid allows suspicious requests to continue but logs a
1776 security warning and blocks caching of the response.
1778 * Forward-proxy traffic is not checked at all.
1780 * Reverse-proxy traffic is not checked at all.
1782 * Intercepted traffic which passes verification is handled
1785 For now it also forces suspicious requests to go DIRECT to the
1786 original destination, overriding client_dst_passthru for
1787 intercepted requests which fail Host: verification.
1789 For now suspicious intercepted CONNECT requests are always
1790 responded to with an HTTP 409 (Conflict) error page.
1793 NAME: client_dst_passthru
1796 LOC: Config.onoff.client_dst_passthru
1798 With NAT or TPROXY intercepted traffic Squid may pass the request
1799 directly to the original client destination IP or seek a faster
1802 This option (on by default) prevents cache_peer and alternative DNS
1803 entries being used on intercepted traffic. Both of which lead to
1804 the security vulnerability outlined below.
1808 This directive should only be disabled if cache_peer are required.
1810 As described in CVE-2009-0801 when the Host: header alone is used
1811 to determine the destination of a request it becomes trivial for
1812 malicious scripts on remote websites to bypass browser same-origin
1813 security policy and sandboxing protections.
1815 The cause of this is that such applets are allowed to perform their
1816 own HTTP stack, in which case the same-origin policy of the browser
1817 sandbox only verifies that the applet tries to contact the same IP
1818 as from where it was loaded at the IP level. The Host: header may
1819 be different from the connected IP and approved origin.
1825 -----------------------------------------------------------------------------
1828 NAME: ssl_unclean_shutdown
1832 LOC: Config.SSL.unclean_shutdown
1834 Some browsers (especially MSIE) bugs out on SSL shutdown
1841 LOC: Config.SSL.ssl_engine
1844 The OpenSSL engine to use. You will need to set this if you
1845 would like to use hardware SSL acceleration for example.
1848 NAME: sslproxy_client_certificate
1851 LOC: Config.ssl_client.cert
1854 Client SSL Certificate to use when proxying https:// URLs
1857 NAME: sslproxy_client_key
1860 LOC: Config.ssl_client.key
1863 Client SSL Key to use when proxying https:// URLs
1866 NAME: sslproxy_version
1869 LOC: Config.ssl_client.version
1872 SSL version level to use when proxying https:// URLs
1874 The versions of SSL/TLS supported:
1876 1 automatic (default)
1884 NAME: sslproxy_options
1887 LOC: Config.ssl_client.options
1890 SSL implementation options to use when proxying https:// URLs
1892 The most important being:
1894 NO_SSLv2 Disallow the use of SSLv2
1895 NO_SSLv3 Disallow the use of SSLv3
1896 NO_TLSv1 Disallow the use of TLSv1.0
1897 NO_TLSv1_1 Disallow the use of TLSv1.1
1898 NO_TLSv1_2 Disallow the use of TLSv1.2
1900 Always create a new key when using temporary/ephemeral
1903 Disable use of RFC5077 session tickets. Some servers
1904 may have problems understanding the TLS extension due
1905 to ambiguous specification in RFC4507.
1906 ALL Enable various bug workarounds suggested as "harmless"
1907 by OpenSSL. Be warned that this may reduce SSL/TLS
1908 strength to some attacks.
1910 See the OpenSSL SSL_CTX_set_options documentation for a
1911 complete list of possible options.
1914 NAME: sslproxy_cipher
1917 LOC: Config.ssl_client.cipher
1920 SSL cipher list to use when proxying https:// URLs
1922 Colon separated list of supported ciphers.
1925 NAME: sslproxy_cafile
1928 LOC: Config.ssl_client.cafile
1931 file containing CA certificates to use when verifying server
1932 certificates while proxying https:// URLs
1935 NAME: sslproxy_capath
1938 LOC: Config.ssl_client.capath
1941 directory containing CA certificates to use when verifying
1942 server certificates while proxying https:// URLs
1948 LOC: Config.accessList.ssl_bump
1951 This ACL controls which CONNECT requests to an http_port
1952 marked with an sslBump flag are actually "bumped". Please
1953 see the sslBump flag of an http_port option for more details
1954 about decoding proxied SSL connections.
1956 By default, no requests are bumped.
1958 See also: http_port ssl-bump
1960 This clause supports both fast and slow acl types.
1961 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1964 # Example: Bump all requests except those originating from localhost and
1965 # those going to webax.com or example.com sites.
1967 acl localhost src 127.0.0.1/32
1968 acl broken_sites dstdomain .webax.com
1969 acl broken_sites dstdomain .example.com
1970 ssl_bump deny localhost
1971 ssl_bump deny broken_sites
1975 NAME: sslproxy_flags
1978 LOC: Config.ssl_client.flags
1981 Various flags modifying the use of SSL while proxying https:// URLs:
1982 DONT_VERIFY_PEER Accept certificates that fail verification.
1983 For refined control, see sslproxy_cert_error.
1984 NO_DEFAULT_CA Don't use the default CA list built in
1988 NAME: sslproxy_cert_error
1991 LOC: Config.ssl_client.cert_error
1994 Use this ACL to bypass server certificate validation errors.
1996 For example, the following lines will bypass all validation errors
1997 when talking to servers for example.com. All other
1998 validation errors will result in ERR_SECURE_CONNECT_FAIL error.
2000 acl BrokenButTrustedServers dstdomain example.com
2001 sslproxy_cert_error allow BrokenButTrustedServers
2002 sslproxy_cert_error deny all
2004 This clause only supports fast acl types.
2005 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2006 Using slow acl types may result in server crashes
2008 Without this option, all server certificate validation errors
2009 terminate the transaction. Bypassing validation errors is dangerous
2010 because an error usually implies that the server cannot be trusted and
2011 the connection may be insecure.
2013 See also: sslproxy_flags and DONT_VERIFY_PEER.
2015 Default setting: sslproxy_cert_error deny all
2018 NAME: sslpassword_program
2021 LOC: Config.Program.ssl_password
2024 Specify a program used for entering SSL key passphrases
2025 when using encrypted SSL certificate keys. If not specified
2026 keys must either be unencrypted, or Squid started with the -N
2027 option to allow it to query interactively for the passphrase.
2029 The key file name is given as argument to the program allowing
2030 selection of the right password if you have multiple encrypted
2035 OPTIONS RELATING TO EXTERNAL SSL_CRTD
2036 -----------------------------------------------------------------------------
2039 NAME: sslcrtd_program
2042 DEFAULT: @DEFAULT_SSL_CRTD@ -s @DEFAULT_SSL_DB_DIR@ -M 4MB
2043 LOC: Ssl::TheConfig.ssl_crtd
2045 Specify the location and options of the executable for ssl_crtd process.
2046 @DEFAULT_SSL_CRTD@ program requires -s and -M parameters
2047 For more information use:
2048 @DEFAULT_SSL_CRTD@ -h
2051 NAME: sslcrtd_children
2052 TYPE: HelperChildConfig
2054 DEFAULT: 32 startup=5 idle=1
2055 LOC: Ssl::TheConfig.ssl_crtdChildren
2057 The maximum number of processes spawn to service ssl server.
2058 The maximum this may be safely set to is 32.
2060 The startup= and idle= options allow some measure of skew in your
2065 Sets the minimum number of processes to spawn when Squid
2066 starts or reconfigures. When set to zero the first request will
2067 cause spawning of the first child process to handle it.
2069 Starting too few children temporary slows Squid under load while it
2070 tries to spawn enough additional processes to cope with traffic.
2074 Sets a minimum of how many processes Squid is to try and keep available
2075 at all times. When traffic begins to rise above what the existing
2076 processes can handle this many more will be spawned up to the maximum
2077 configured. A minimum setting of 1 is required.
2079 You must have at least one ssl_crtd process.
2083 OPTIONS WHICH AFFECT THE NEIGHBOR SELECTION ALGORITHM
2084 -----------------------------------------------------------------------------
2092 To specify other caches in a hierarchy, use the format:
2094 cache_peer hostname type http-port icp-port [options]
2099 # hostname type port port options
2100 # -------------------- -------- ----- ----- -----------
2101 cache_peer parent.foo.net parent 3128 3130 default
2102 cache_peer sib1.foo.net sibling 3128 3130 proxy-only
2103 cache_peer sib2.foo.net sibling 3128 3130 proxy-only
2104 cache_peer example.com parent 80 0 default
2105 cache_peer cdn.example.com sibling 3128 0
2107 type: either 'parent', 'sibling', or 'multicast'.
2109 proxy-port: The port number where the peer accept HTTP requests.
2110 For other Squid proxies this is usually 3128
2111 For web servers this is usually 80
2113 icp-port: Used for querying neighbor caches about objects.
2114 Set to 0 if the peer does not support ICP or HTCP.
2115 See ICP and HTCP options below for additional details.
2118 ==== ICP OPTIONS ====
2120 You MUST also set icp_port and icp_access explicitly when using these options.
2121 The defaults will prevent peer traffic using ICP.
2124 no-query Disable ICP queries to this neighbor.
2127 Indicates the named peer is a member of a multicast group.
2128 ICP queries will not be sent directly to the peer, but ICP
2129 replies will be accepted from it.
2131 closest-only Indicates that, for ICP_OP_MISS replies, we'll only forward
2132 CLOSEST_PARENT_MISSes and never FIRST_PARENT_MISSes.
2135 To only send ICP queries to this neighbor infrequently.
2136 This is used to keep the neighbor round trip time updated
2137 and is usually used in conjunction with weighted-round-robin.
2140 ==== HTCP OPTIONS ====
2142 You MUST also set htcp_port and htcp_access explicitly when using these options.
2143 The defaults will prevent peer traffic using HTCP.
2146 htcp Send HTCP, instead of ICP, queries to the neighbor.
2147 You probably also want to set the "icp-port" to 4827
2148 instead of 3130. This directive accepts a comma separated
2149 list of options described below.
2151 htcp=oldsquid Send HTCP to old Squid versions (2.5 or earlier).
2153 htcp=no-clr Send HTCP to the neighbor but without
2154 sending any CLR requests. This cannot be used with
2157 htcp=only-clr Send HTCP to the neighbor but ONLY CLR requests.
2158 This cannot be used with no-clr.
2161 Send HTCP to the neighbor including CLRs but only when
2162 they do not result from PURGE requests.
2165 Forward any HTCP CLR requests this proxy receives to the peer.
2168 ==== PEER SELECTION METHODS ====
2170 The default peer selection method is ICP, with the first responding peer
2171 being used as source. These options can be used for better load balancing.
2174 default This is a parent cache which can be used as a "last-resort"
2175 if a peer cannot be located by any of the peer-selection methods.
2176 If specified more than once, only the first is used.
2178 round-robin Load-Balance parents which should be used in a round-robin
2179 fashion in the absence of any ICP queries.
2180 weight=N can be used to add bias.
2182 weighted-round-robin
2183 Load-Balance parents which should be used in a round-robin
2184 fashion with the frequency of each parent being based on the
2185 round trip time. Closer parents are used more often.
2186 Usually used for background-ping parents.
2187 weight=N can be used to add bias.
2189 carp Load-Balance parents which should be used as a CARP array.
2190 The requests will be distributed among the parents based on the
2191 CARP load balancing hash function based on their weight.
2193 userhash Load-balance parents based on the client proxy_auth or ident username.
2195 sourcehash Load-balance parents based on the client source IP.
2198 To be used only for cache peers of type "multicast".
2199 ALL members of this multicast group have "sibling"
2200 relationship with it, not "parent". This is to a multicast
2201 group when the requested object would be fetched only from
2202 a "parent" cache, anyway. It's useful, e.g., when
2203 configuring a pool of redundant Squid proxies, being
2204 members of the same multicast group.
2207 ==== PEER SELECTION OPTIONS ====
2209 weight=N use to affect the selection of a peer during any weighted
2210 peer-selection mechanisms.
2211 The weight must be an integer; default is 1,
2212 larger weights are favored more.
2213 This option does not affect parent selection if a peering
2214 protocol is not in use.
2216 basetime=N Specify a base amount to be subtracted from round trip
2218 It is subtracted before division by weight in calculating
2219 which parent to fectch from. If the rtt is less than the
2220 base time the rtt is set to a minimal value.
2222 ttl=N Specify a TTL to use when sending multicast ICP queries
2224 Only useful when sending to a multicast group.
2225 Because we don't accept ICP replies from random
2226 hosts, you must configure other group members as
2227 peers with the 'multicast-responder' option.
2229 no-delay To prevent access to this neighbor from influencing the
2232 digest-url=URL Tell Squid to fetch the cache digest (if digests are
2233 enabled) for this host from the specified URL rather
2234 than the Squid default location.
2237 ==== CARP OPTIONS ====
2239 carp-key=key-specification
2240 use a different key than the full URL to hash against the peer.
2241 the key-specification is a comma-separated list of the keywords
2242 scheme, host, port, path, params
2243 Order is not important.
2245 ==== ACCELERATOR / REVERSE-PROXY OPTIONS ====
2247 originserver Causes this parent to be contacted as an origin server.
2248 Meant to be used in accelerator setups when the peer
2252 Set the Host header of requests forwarded to this peer.
2253 Useful in accelerator setups where the server (peer)
2254 expects a certain domain name but clients may request
2255 others. ie example.com or www.example.com
2257 no-digest Disable request of cache digests.
2260 Disables requesting ICMP RTT database (NetDB).
2263 ==== AUTHENTICATION OPTIONS ====
2266 If this is a personal/workgroup proxy and your parent
2267 requires proxy authentication.
2269 Note: The string can include URL escapes (i.e. %20 for
2270 spaces). This also means % must be written as %%.
2273 Send login details received from client to this peer.
2274 Both Proxy- and WWW-Authorization headers are passed
2275 without alteration to the peer.
2276 Authentication is not required by Squid for this to work.
2278 Note: This will pass any form of authentication but
2279 only Basic auth will work through a proxy unless the
2280 connection-auth options are also used.
2282 login=PASS Send login details received from client to this peer.
2283 Authentication is not required by this option.
2285 If there are no client-provided authentication headers
2286 to pass on, but username and password are available
2287 from an external ACL user= and password= result tags
2288 they may be sent instead.
2290 Note: To combine this with proxy_auth both proxies must
2291 share the same user database as HTTP only allows for
2292 a single login (one for proxy, one for origin server).
2293 Also be warned this will expose your users proxy
2294 password to the peer. USE WITH CAUTION
2297 Send the username to the upstream cache, but with a
2298 fixed password. This is meant to be used when the peer
2299 is in another administrative domain, but it is still
2300 needed to identify each user.
2301 The star can optionally be followed by some extra
2302 information which is added to the username. This can
2303 be used to identify this proxy to the peer, similar to
2304 the login=username:password option above.
2307 If this is a personal/workgroup proxy and your parent
2308 requires a secure proxy authentication.
2309 The first principal from the default keytab or defined by
2310 the environment variable KRB5_KTNAME will be used.
2312 WARNING: The connection may transmit requests from multiple
2313 clients. Negotiate often assumes end-to-end authentication
2314 and a single-client. Which is not strictly true here.
2316 login=NEGOTIATE:principal_name
2317 If this is a personal/workgroup proxy and your parent
2318 requires a secure proxy authentication.
2319 The principal principal_name from the default keytab or
2320 defined by the environment variable KRB5_KTNAME will be
2323 WARNING: The connection may transmit requests from multiple
2324 clients. Negotiate often assumes end-to-end authentication
2325 and a single-client. Which is not strictly true here.
2327 connection-auth=on|off
2328 Tell Squid that this peer does or not support Microsoft
2329 connection oriented authentication, and any such
2330 challenges received from there should be ignored.
2331 Default is auto to automatically determine the status
2335 ==== SSL / HTTPS / TLS OPTIONS ====
2337 ssl Encrypt connections to this peer with SSL/TLS.
2339 sslcert=/path/to/ssl/certificate
2340 A client SSL certificate to use when connecting to
2343 sslkey=/path/to/ssl/key
2344 The private SSL key corresponding to sslcert above.
2345 If 'sslkey' is not specified 'sslcert' is assumed to
2346 reference a combined file containing both the
2347 certificate and the key.
2349 sslversion=1|2|3|4|5|6
2350 The SSL version to use when connecting to this peer
2351 1 = automatic (default)
2358 sslcipher=... The list of valid SSL ciphers to use when connecting
2361 ssloptions=... Specify various SSL implementation options:
2363 NO_SSLv2 Disallow the use of SSLv2
2364 NO_SSLv3 Disallow the use of SSLv3
2365 NO_TLSv1 Disallow the use of TLSv1.0
2366 NO_TLSv1_1 Disallow the use of TLSv1.1
2367 NO_TLSv1_2 Disallow the use of TLSv1.2
2369 Always create a new key when using
2370 temporary/ephemeral DH key exchanges
2371 ALL Enable various bug workarounds
2372 suggested as "harmless" by OpenSSL
2373 Be warned that this reduces SSL/TLS
2374 strength to some attacks.
2376 See the OpenSSL SSL_CTX_set_options documentation for a
2379 sslcafile=... A file containing additional CA certificates to use
2380 when verifying the peer certificate.
2382 sslcapath=... A directory containing additional CA certificates to
2383 use when verifying the peer certificate.
2385 sslcrlfile=... A certificate revocation list file to use when
2386 verifying the peer certificate.
2388 sslflags=... Specify various flags modifying the SSL implementation:
2391 Accept certificates even if they fail to
2394 Don't use the default CA list built in
2397 Don't verify the peer certificate
2398 matches the server name
2400 ssldomain= The peer name as advertised in it's certificate.
2401 Used for verifying the correctness of the received peer
2402 certificate. If not specified the peer hostname will be
2406 Enable the "Front-End-Https: On" header needed when
2407 using Squid as a SSL frontend in front of Microsoft OWA.
2408 See MS KB document Q307347 for details on this header.
2409 If set to auto the header will only be added if the
2410 request is forwarded as a https:// URL.
2413 ==== GENERAL OPTIONS ====
2416 A peer-specific connect timeout.
2417 Also see the peer_connect_timeout directive.
2419 connect-fail-limit=N
2420 How many times connecting to a peer must fail before
2421 it is marked as down. Default is 10.
2423 allow-miss Disable Squid's use of only-if-cached when forwarding
2424 requests to siblings. This is primarily useful when
2425 icp_hit_stale is used by the sibling. To extensive use
2426 of this option may result in forwarding loops, and you
2427 should avoid having two-way peerings with this option.
2428 For example to deny peer usage on requests from peer
2429 by denying cache_peer_access if the source is a peer.
2431 max-conn=N Limit the amount of connections Squid may open to this
2434 name=xxx Unique name for the peer.
2435 Required if you have multiple peers on the same host
2436 but different ports.
2437 This name can be used in cache_peer_access and similar
2438 directives to dentify the peer.
2439 Can be used by outgoing access controls through the
2442 no-tproxy Do not use the client-spoof TPROXY support when forwarding
2443 requests to this peer. Use normal address selection instead.
2445 proxy-only objects fetched from the peer will not be stored locally.
2449 NAME: cache_peer_domain cache_host_domain
2454 Use to limit the domains for which a neighbor cache will be
2457 cache_peer_domain cache-host domain [domain ...]
2458 cache_peer_domain cache-host !domain
2460 For example, specifying
2462 cache_peer_domain parent.foo.net .edu
2464 has the effect such that UDP query packets are sent to
2465 'bigserver' only when the requested object exists on a
2466 server in the .edu domain. Prefixing the domainname
2467 with '!' means the cache will be queried for objects
2470 NOTE: * Any number of domains may be given for a cache-host,
2471 either on the same or separate lines.
2472 * When multiple domains are given for a particular
2473 cache-host, the first matched domain is applied.
2474 * Cache hosts with no domain restrictions are queried
2476 * There are no defaults.
2477 * There is also a 'cache_peer_access' tag in the ACL
2481 NAME: cache_peer_access
2486 Similar to 'cache_peer_domain' but provides more flexibility by
2489 cache_peer_access cache-host allow|deny [!]aclname ...
2491 The syntax is identical to 'http_access' and the other lists of
2492 ACL elements. See the comments for 'http_access' below, or
2493 the Squid FAQ (http://wiki.squid-cache.org/SquidFaq/SquidAcl).
2496 NAME: neighbor_type_domain
2497 TYPE: hostdomaintype
2501 usage: neighbor_type_domain neighbor parent|sibling domain domain ...
2503 Modifying the neighbor type for specific domains is now
2504 possible. You can treat some domains differently than the
2505 default neighbor type specified on the 'cache_peer' line.
2506 Normally it should only be necessary to list domains which
2507 should be treated differently because the default neighbor type
2508 applies for hostnames which do not match domains listed here.
2511 cache_peer cache.foo.org parent 3128 3130
2512 neighbor_type_domain cache.foo.org sibling .com .net
2513 neighbor_type_domain cache.foo.org sibling .au .de
2516 NAME: dead_peer_timeout
2520 LOC: Config.Timeout.deadPeer
2522 This controls how long Squid waits to declare a peer cache
2523 as "dead." If there are no ICP replies received in this
2524 amount of time, Squid will declare the peer dead and not
2525 expect to receive any further ICP replies. However, it
2526 continues to send ICP queries, and will mark the peer as
2527 alive upon receipt of the first subsequent ICP reply.
2529 This timeout also affects when Squid expects to receive ICP
2530 replies from peers. If more than 'dead_peer' seconds have
2531 passed since the last ICP reply was received, Squid will not
2532 expect to receive an ICP reply on the next query. Thus, if
2533 your time between requests is greater than this timeout, you
2534 will see a lot of requests sent DIRECT to origin servers
2535 instead of to your parents.
2538 NAME: forward_max_tries
2541 LOC: Config.forward_max_tries
2543 Controls how many different forward paths Squid will try
2544 before giving up. See also forward_timeout.
2546 NOTE: connect_retries (default: none) can make each of these
2547 possible forwarding paths be tried multiple times.
2550 NAME: hierarchy_stoplist
2553 LOC: Config.hierarchy_stoplist
2555 A list of words which, if found in a URL, cause the object to
2556 be handled directly by this cache. In other words, use this
2557 to not query neighbor caches for certain objects. You may
2558 list this option multiple times.
2561 hierarchy_stoplist cgi-bin ?
2563 Note: never_direct overrides this option.
2567 MEMORY CACHE OPTIONS
2568 -----------------------------------------------------------------------------
2575 LOC: Config.memMaxSize
2577 NOTE: THIS PARAMETER DOES NOT SPECIFY THE MAXIMUM PROCESS SIZE.
2578 IT ONLY PLACES A LIMIT ON HOW MUCH ADDITIONAL MEMORY SQUID WILL
2579 USE AS A MEMORY CACHE OF OBJECTS. SQUID USES MEMORY FOR OTHER
2580 THINGS AS WELL. SEE THE SQUID FAQ SECTION 8 FOR DETAILS.
2582 'cache_mem' specifies the ideal amount of memory to be used
2584 * In-Transit objects
2586 * Negative-Cached objects
2588 Data for these objects are stored in 4 KB blocks. This
2589 parameter specifies the ideal upper limit on the total size of
2590 4 KB blocks allocated. In-Transit objects take the highest
2593 In-transit objects have priority over the others. When
2594 additional space is needed for incoming data, negative-cached
2595 and hot objects will be released. In other words, the
2596 negative-cached and hot objects will fill up any unused space
2597 not needed for in-transit objects.
2599 If circumstances require, this limit will be exceeded.
2600 Specifically, if your incoming request rate requires more than
2601 'cache_mem' of memory to hold in-transit objects, Squid will
2602 exceed this limit to satisfy the new requests. When the load
2603 decreases, blocks will be freed until the high-water mark is
2604 reached. Thereafter, blocks will be used to store hot
2607 If shared memory caching is enabled, Squid does not use the shared
2608 cache space for in-transit objects, but they still consume as much
2609 local memory as they need. For more details about the shared memory
2610 cache, see memory_cache_shared.
2613 NAME: maximum_object_size_in_memory
2617 LOC: Config.Store.maxInMemObjSize
2619 Objects greater than this size will not be attempted to kept in
2620 the memory cache. This should be set high enough to keep objects
2621 accessed frequently in memory to improve performance whilst low
2622 enough to keep larger objects from hoarding cache_mem.
2625 NAME: memory_cache_shared
2628 LOC: Config.memShared
2630 DEFAULT_DOC: "on" where supported if doing memory caching with multiple SMP workers.
2632 Controls whether the memory cache is shared among SMP workers.
2634 The shared memory cache is meant to occupy cache_mem bytes and replace
2635 the non-shared memory cache, although some entities may still be
2636 cached locally by workers for now (e.g., internal and in-transit
2637 objects may be served from a local memory cache even if shared memory
2638 caching is enabled).
2640 By default, the memory cache is shared if and only if all of the
2641 following conditions are satisfied: Squid runs in SMP mode with
2642 multiple workers, cache_mem is positive, and Squid environment
2643 supports required IPC primitives (e.g., POSIX shared memory segments
2644 and GCC-style atomic operations).
2646 To avoid blocking locks, shared memory uses opportunistic algorithms
2647 that do not guarantee that every cachable entity that could have been
2648 shared among SMP workers will actually be shared.
2650 Currently, entities exceeding 32KB in size cannot be shared.
2653 NAME: memory_cache_mode
2658 Controls which objects to keep in the memory cache (cache_mem)
2660 always Keep most recently fetched objects in memory (default)
2662 disk Only disk cache hits are kept in memory, which means
2663 an object must first be cached on disk and then hit
2664 a second time before cached in memory.
2666 network Only objects fetched from network is kept in memory
2669 NAME: memory_replacement_policy
2671 LOC: Config.memPolicy
2674 The memory replacement policy parameter determines which
2675 objects are purged from memory when memory space is needed.
2677 See cache_replacement_policy for details.
2682 -----------------------------------------------------------------------------
2685 NAME: cache_replacement_policy
2687 LOC: Config.replPolicy
2690 The cache replacement policy parameter determines which
2691 objects are evicted (replaced) when disk space is needed.
2693 lru : Squid's original list based LRU policy
2694 heap GDSF : Greedy-Dual Size Frequency
2695 heap LFUDA: Least Frequently Used with Dynamic Aging
2696 heap LRU : LRU policy implemented using a heap
2698 Applies to any cache_dir lines listed below this.
2700 The LRU policies keeps recently referenced objects.
2702 The heap GDSF policy optimizes object hit rate by keeping smaller
2703 popular objects in cache so it has a better chance of getting a
2704 hit. It achieves a lower byte hit rate than LFUDA though since
2705 it evicts larger (possibly popular) objects.
2707 The heap LFUDA policy keeps popular objects in cache regardless of
2708 their size and thus optimizes byte hit rate at the expense of
2709 hit rate since one large, popular object will prevent many
2710 smaller, slightly less popular objects from being cached.
2712 Both policies utilize a dynamic aging mechanism that prevents
2713 cache pollution that can otherwise occur with frequency-based
2714 replacement policies.
2716 NOTE: if using the LFUDA replacement policy you should increase
2717 the value of maximum_object_size above its default of 4096 KB to
2718 to maximize the potential byte hit rate improvement of LFUDA.
2720 For more information about the GDSF and LFUDA cache replacement
2721 policies see http://www.hpl.hp.com/techreports/1999/HPL-1999-69.html
2722 and http://fog.hpl.external.hp.com/techreports/98/HPL-98-173.html.
2728 LOC: Config.cacheSwap
2732 cache_dir Type Directory-Name Fs-specific-data [options]
2734 You can specify multiple cache_dir lines to spread the
2735 cache among different disk partitions.
2737 Type specifies the kind of storage system to use. Only "ufs"
2738 is built by default. To enable any of the other storage systems
2739 see the --enable-storeio configure option.
2741 'Directory' is a top-level directory where cache swap
2742 files will be stored. If you want to use an entire disk
2743 for caching, this can be the mount-point directory.
2744 The directory must exist and be writable by the Squid
2745 process. Squid will NOT create this directory for you.
2747 In SMP configurations, cache_dir must not precede the workers option
2748 and should use configuration macros or conditionals to give each
2749 worker interested in disk caching a dedicated cache directory.
2753 "ufs" is the old well-known Squid storage format that has always
2756 cache_dir ufs Directory-Name Mbytes L1 L2 [options]
2758 'Mbytes' is the amount of disk space (MB) to use under this
2759 directory. The default is 100 MB. Change this to suit your
2760 configuration. Do NOT put the size of your disk drive here.
2761 Instead, if you want Squid to use the entire disk drive,
2762 subtract 20% and use that value.
2764 'L1' is the number of first-level subdirectories which
2765 will be created under the 'Directory'. The default is 16.
2767 'L2' is the number of second-level subdirectories which
2768 will be created under each first-level directory. The default
2771 The aufs store type:
2773 "aufs" uses the same storage format as "ufs", utilizing
2774 POSIX-threads to avoid blocking the main Squid process on
2775 disk-I/O. This was formerly known in Squid as async-io.
2777 cache_dir aufs Directory-Name Mbytes L1 L2 [options]
2779 see argument descriptions under ufs above
2781 The diskd store type:
2783 "diskd" uses the same storage format as "ufs", utilizing a
2784 separate process to avoid blocking the main Squid process on
2787 cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n]
2789 see argument descriptions under ufs above
2791 Q1 specifies the number of unacknowledged I/O requests when Squid
2792 stops opening new files. If this many messages are in the queues,
2793 Squid won't open new files. Default is 64
2795 Q2 specifies the number of unacknowledged messages when Squid
2796 starts blocking. If this many messages are in the queues,
2797 Squid blocks until it receives some replies. Default is 72
2799 When Q1 < Q2 (the default), the cache directory is optimized
2800 for lower response time at the expense of a decrease in hit
2801 ratio. If Q1 > Q2, the cache directory is optimized for
2802 higher hit ratio at the expense of an increase in response
2805 The rock store type:
2807 cache_dir rock Directory-Name Mbytes <max-size=bytes> [options]
2809 The Rock Store type is a database-style storage. All cached
2810 entries are stored in a "database" file, using fixed-size slots,
2811 one entry per slot. The database size is specified in MB. The
2812 slot size is specified in bytes using the max-size option. See
2813 below for more info on the max-size option.
2815 swap-timeout=msec: Squid will not start writing a miss to or
2816 reading a hit from disk if it estimates that the swap operation
2817 will take more than the specified number of milliseconds. By
2818 default and when set to zero, disables the disk I/O time limit
2819 enforcement. Ignored when using blocking I/O module because
2820 blocking synchronous I/O does not allow Squid to estimate the
2821 expected swap wait time.
2823 max-swap-rate=swaps/sec: Artificially limits disk access using
2824 the specified I/O rate limit. Swap out requests that
2825 would cause the average I/O rate to exceed the limit are
2826 delayed. Individual swap in requests (i.e., hits or reads) are
2827 not delayed, but they do contribute to measured swap rate and
2828 since they are placed in the same FIFO queue as swap out
2829 requests, they may wait longer if max-swap-rate is smaller.
2830 This is necessary on file systems that buffer "too
2831 many" writes and then start blocking Squid and other processes
2832 while committing those writes to disk. Usually used together
2833 with swap-timeout to avoid excessive delays and queue overflows
2834 when disk demand exceeds available disk "bandwidth". By default
2835 and when set to zero, disables the disk I/O rate limit
2836 enforcement. Currently supported by IpcIo module only.
2839 The coss store type:
2841 NP: COSS filesystem in Squid-3 has been deemed too unstable for
2842 production use and has thus been removed from this release.
2843 We hope that it can be made usable again soon.
2845 block-size=n defines the "block size" for COSS cache_dir's.
2846 Squid uses file numbers as block numbers. Since file numbers
2847 are limited to 24 bits, the block size determines the maximum
2848 size of the COSS partition. The default is 512 bytes, which
2849 leads to a maximum cache_dir size of 512<<24, or 8 GB. Note
2850 you should not change the coss block size after Squid
2851 has written some objects to the cache_dir.
2853 The coss file store has changed from 2.5. Now it uses a file
2854 called 'stripe' in the directory names in the config - and
2855 this will be created by squid -z.
2859 no-store, no new objects should be stored to this cache_dir
2861 min-size=n, refers to the min object size in bytes this cache_dir
2862 will accept. It's used to restrict a cache_dir to only store
2863 large objects (e.g. aufs) while other storedirs are optimized
2864 for smaller objects (e.g. COSS). Defaults to 0.
2866 max-size=n, refers to the max object size in bytes this cache_dir
2867 supports. It is used to select the cache_dir to store the object.
2868 Note: To make optimal use of the max-size limits you should order
2869 the cache_dir lines with the smallest max-size value first and the
2870 ones with no max-size specification last.
2872 Note for coss, max-size must be less than COSS_MEMBUF_SZ,
2873 which can be changed with the --with-coss-membuf-size=N configure
2877 # Uncomment and adjust the following to add a disk cache directory.
2878 #cache_dir ufs @DEFAULT_SWAP_DIR@ 100 16 256
2882 NAME: store_dir_select_algorithm
2884 LOC: Config.store_dir_select_algorithm
2887 Set this to 'round-robin' as an alternative.
2890 NAME: max_open_disk_fds
2892 LOC: Config.max_open_disk_fds
2895 To avoid having disk as the I/O bottleneck Squid can optionally
2896 bypass the on-disk cache if more than this amount of disk file
2897 descriptors are open.
2899 A value of 0 indicates no limit.
2902 NAME: minimum_object_size
2906 LOC: Config.Store.minObjectSize
2908 Objects smaller than this size will NOT be saved on disk. The
2909 value is specified in kilobytes, and the default is 0 KB, which
2910 means there is no minimum.
2913 NAME: maximum_object_size
2917 LOC: Config.Store.maxObjectSize
2919 Objects larger than this size will NOT be saved on disk. The
2920 value is specified in kilobytes, and the default is 4MB. If
2921 you wish to get a high BYTES hit ratio, you should probably
2922 increase this (one 32 MB object hit counts for 3200 10KB
2923 hits). If you wish to increase speed more than your want to
2924 save bandwidth you should leave this low.
2926 NOTE: if using the LFUDA replacement policy you should increase
2927 this value to maximize the byte hit rate improvement of LFUDA!
2928 See replacement_policy below for a discussion of this policy.
2931 NAME: cache_swap_low
2932 COMMENT: (percent, 0-100)
2935 LOC: Config.Swap.lowWaterMark
2938 NAME: cache_swap_high
2939 COMMENT: (percent, 0-100)
2942 LOC: Config.Swap.highWaterMark
2945 The low- and high-water marks for cache object replacement.
2946 Replacement begins when the swap (disk) usage is above the
2947 low-water mark and attempts to maintain utilization near the
2948 low-water mark. As swap utilization gets close to high-water
2949 mark object eviction becomes more aggressive. If utilization is
2950 close to the low-water mark less replacement is done each time.
2952 Defaults are 90% and 95%. If you have a large cache, 5% could be
2953 hundreds of MB. If this is the case you may wish to set these
2954 numbers closer together.
2959 -----------------------------------------------------------------------------
2969 logformat <name> <format specification>
2971 Defines an access log format.
2973 The <format specification> is a string with embedded % format codes
2975 % format codes all follow the same basic structure where all but
2976 the formatcode is optional. Output strings are automatically escaped
2977 as required according to their context and the output format
2978 modifiers are usually not needed, but can be specified if an explicit
2979 output format is desired.
2981 % ["|[|'|#] [-] [[0]width] [{argument}] formatcode
2983 " output in quoted string format
2984 [ output in squid text log format as used by log_mime_hdrs
2985 # output in URL quoted format
2990 width minimum and/or maximum field width:
2991 [width_min][.width_max]
2992 When minimum starts with 0, the field is zero-padded.
2993 String values exceeding maximum width are truncated.
2995 {arg} argument such as header name etc
2999 % a literal % character
3000 sn Unique sequence number per log line entry
3001 err_code The ID of an error response served by Squid or
3002 a similar internal error identifier.
3003 err_detail Additional err_code-dependent error information.
3005 Connection related format codes:
3007 >a Client source IP address
3009 >p Client source port
3010 >eui Client source EUI (MAC address, EUI-48 or EUI-64 identifier)
3011 >la Local IP address the client connected to
3012 >lp Local port number the client connected to
3014 la Local listening IP address the client connection was connected to.
3015 lp Local listening port number the client connection was connected to.
3017 <a Server IP address of the last server or peer connection
3018 <A Server FQDN or peer name
3019 <p Server port number of the last server or peer connection
3020 <la Local IP address of the last server or peer connection
3021 <lp Local port number of the last server or peer connection
3023 Time related format codes:
3025 ts Seconds since epoch
3026 tu subsecond time (milliseconds)
3027 tl Local time. Optional strftime format argument
3028 default %d/%b/%Y:%H:%M:%S %z
3029 tg GMT time. Optional strftime format argument
3030 default %d/%b/%Y:%H:%M:%S %z
3031 tr Response time (milliseconds)
3032 dt Total time spent making DNS lookups (milliseconds)
3034 Access Control related format codes:
3036 et Tag returned by external acl
3037 ea Log string returned by external acl
3038 un User name (any available)
3039 ul User name from authentication
3040 ue User name from external acl helper
3041 ui User name from ident
3042 us User name from SSL
3044 HTTP related format codes:
3046 [http::]>h Original request header. Optional header name argument
3047 on the format header[:[separator]element]
3048 [http::]>ha The HTTP request headers after adaptation and redirection.
3049 Optional header name argument as for >h
3050 [http::]<h Reply header. Optional header name argument
3052 [http::]>Hs HTTP status code sent to the client
3053 [http::]<Hs HTTP status code received from the next hop
3054 [http::]<bs Number of HTTP-equivalent message body bytes
3055 received from the next hop, excluding chunked
3056 transfer encoding and control messages.
3057 Generated FTP/Gopher listings are treated as
3059 [http::]mt MIME content type
3060 [http::]rm Request method (GET/POST etc)
3061 [http::]>rm Request method from client
3062 [http::]<rm Request method sent to server or peer
3063 [http::]ru Request URL from client (historic, filtered for logging)
3064 [http::]>ru Request URL from client
3065 [http::]<ru Request URL sent to server or peer
3066 [http::]rp Request URL-Path excluding hostname
3067 [http::]>rp Request URL-Path excluding hostname from client
3068 [http::]<rp Request URL-Path excluding hostname sento to server or peer
3069 [http::]rv Request protocol version
3070 [http::]>rv Request protocol version from client
3071 [http::]<rv Request protocol version sent to server or peer
3072 [http::]<st Sent reply size including HTTP headers
3073 [http::]>st Received request size including HTTP headers. In the
3074 case of chunked requests the chunked encoding metadata
3076 [http::]>sh Received HTTP request headers size
3077 [http::]<sh Sent HTTP reply headers size
3078 [http::]st Request+Reply size including HTTP headers
3079 [http::]<sH Reply high offset sent
3080 [http::]<sS Upstream object size
3081 [http::]<pt Peer response time in milliseconds. The timer starts
3082 when the last request byte is sent to the next hop
3083 and stops when the last response byte is received.
3084 [http::]<tt Total server-side time in milliseconds. The timer
3085 starts with the first connect request (or write I/O)
3086 sent to the first selected peer. The timer stops
3087 with the last I/O with the last peer.
3089 Squid handling related format codes:
3091 Ss Squid request status (TCP_MISS etc)
3092 Sh Squid hierarchy status (DEFAULT_PARENT etc)
3094 If ICAP is enabled, the following code becomes available (as
3095 well as ICAP log codes documented with the icap_log option):
3097 icap::tt Total ICAP processing time for the HTTP
3098 transaction. The timer ticks when ICAP
3099 ACLs are checked and when ICAP
3100 transaction is in progress.
3102 If adaptation is enabled the following three codes become available:
3104 adapt::<last_h The header of the last ICAP response or
3105 meta-information from the last eCAP
3106 transaction related to the HTTP transaction.
3107 Like <h, accepts an optional header name
3110 adapt::sum_trs Summed adaptation transaction response
3111 times recorded as a comma-separated list in
3112 the order of transaction start time. Each time
3113 value is recorded as an integer number,
3114 representing response time of one or more
3115 adaptation (ICAP or eCAP) transaction in
3116 milliseconds. When a failed transaction is
3117 being retried or repeated, its time is not
3118 logged individually but added to the
3119 replacement (next) transaction. See also:
3122 adapt::all_trs All adaptation transaction response times.
3123 Same as adaptation_strs but response times of
3124 individual transactions are never added
3125 together. Instead, all transaction response
3126 times are recorded individually.
3128 You can prefix adapt::*_trs format codes with adaptation
3129 service name in curly braces to record response time(s) specific
3130 to that service. For example: %{my_service}adapt::sum_trs
3132 The default formats available (which do not need re-defining) are:
3134 logformat squid %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %[un %Sh/%<a %mt
3135 logformat common %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st %Ss:%Sh
3136 logformat combined %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
3137 logformat referrer %ts.%03tu %>a %{Referer}>h %ru
3138 logformat useragent %>a [%tl] "%{User-Agent}>h"
3140 NOTE: When the log_mime_hdrs directive is set to ON.
3141 The squid, common and combined formats have a safely encoded copy
3142 of the mime headers appended to each line within a pair of brackets.
3144 NOTE: The common and combined formats are not quite true to the Apache definition.
3145 The logs from Squid contain an extra status and hierarchy code appended.
3149 NAME: access_log cache_access_log
3151 LOC: Config.Log.accesslogs
3152 DEFAULT_IF_NONE: daemon:@DEFAULT_ACCESS_LOG@ squid
3154 These files log client request activities. Has a line every HTTP or
3155 ICP request. The format is:
3156 access_log <module>:<place> [<logformat name> [acl acl ...]]
3157 access_log none [acl acl ...]]
3159 Will log to the specified module:place using the specified format (which
3160 must be defined in a logformat directive) those entries which match
3161 ALL the acl's specified (which must be defined in acl clauses).
3162 If no acl is specified, all requests will be logged to this destination.
3164 ===== Modules Currently available =====
3166 none Do not log any requests matching these ACL.
3167 Do not specify Place or logformat name.
3169 stdio Write each log line to disk immediately at the completion of
3171 Place: the filename and path to be written.
3173 daemon Very similar to stdio. But instead of writing to disk the log
3174 line is passed to a daemon helper for asychronous handling instead.
3175 Place: varies depending on the daemon.
3177 log_file_daemon Place: the file name and path to be written.
3179 syslog To log each request via syslog facility.
3180 Place: The syslog facility and priority level for these entries.
3181 Place Format: facility.priority
3183 where facility could be any of:
3184 authpriv, daemon, local0 ... local7 or user.
3186 And priority could be any of:
3187 err, warning, notice, info, debug.
3189 udp To send each log line as text data to a UDP receiver.
3190 Place: The destination host name or IP and port.
3191 Place Format: //host:port
3193 tcp To send each log line as text data to a TCP receiver.
3194 Place: The destination host name or IP and port.
3195 Place Format: //host:port
3198 access_log daemon:@DEFAULT_ACCESS_LOG@ squid
3204 LOC: Config.Log.icaplogs
3207 ICAP log files record ICAP transaction summaries, one line per
3210 The icap_log option format is:
3211 icap_log <filepath> [<logformat name> [acl acl ...]]
3212 icap_log none [acl acl ...]]
3214 Please see access_log option documentation for details. The two
3215 kinds of logs share the overall configuration approach and many
3218 ICAP processing of a single HTTP message or transaction may
3219 require multiple ICAP transactions. In such cases, multiple
3220 ICAP transaction log lines will correspond to a single access
3223 ICAP log uses logformat codes that make sense for an ICAP
3224 transaction. Header-related codes are applied to the HTTP header
3225 embedded in an ICAP server response, with the following caveats:
3226 For REQMOD, there is no HTTP response header unless the ICAP
3227 server performed request satisfaction. For RESPMOD, the HTTP
3228 request header is the header sent to the ICAP server. For
3229 OPTIONS, there are no HTTP headers.
3231 The following format codes are also available for ICAP logs:
3233 icap::<A ICAP server IP address. Similar to <A.
3235 icap::<service_name ICAP service name from the icap_service
3236 option in Squid configuration file.
3238 icap::ru ICAP Request-URI. Similar to ru.
3240 icap::rm ICAP request method (REQMOD, RESPMOD, or
3241 OPTIONS). Similar to existing rm.
3243 icap::>st Bytes sent to the ICAP server (TCP payload
3244 only; i.e., what Squid writes to the socket).
3246 icap::<st Bytes received from the ICAP server (TCP
3247 payload only; i.e., what Squid reads from
3250 icap::<bs Number of message body bytes received from the
3251 ICAP server. ICAP message body, if any, usually
3252 includes encapsulated HTTP message headers and
3253 possibly encapsulated HTTP message body. The
3254 HTTP body part is dechunked before its size is
3257 icap::tr Transaction response time (in
3258 milliseconds). The timer starts when
3259 the ICAP transaction is created and
3260 stops when the transaction is completed.
3263 icap::tio Transaction I/O time (in milliseconds). The
3264 timer starts when the first ICAP request
3265 byte is scheduled for sending. The timers
3266 stops when the last byte of the ICAP response
3269 icap::to Transaction outcome: ICAP_ERR* for all
3270 transaction errors, ICAP_OPT for OPTION
3271 transactions, ICAP_ECHO for 204
3272 responses, ICAP_MOD for message
3273 modification, and ICAP_SAT for request
3274 satisfaction. Similar to Ss.
3276 icap::Hs ICAP response status code. Similar to Hs.
3278 icap::>h ICAP request header(s). Similar to >h.
3280 icap::<h ICAP response header(s). Similar to <h.
3282 The default ICAP log format, which can be used without an explicit
3283 definition, is called icap_squid:
3285 logformat icap_squid %ts.%03tu %6icap::tr %>a %icap::to/%03icap::Hs %icap::<size %icap::rm %icap::ru% %un -/%icap::<A -
3287 See also: logformat, log_icap, and %adapt::<last_h
3290 NAME: logfile_daemon
3292 DEFAULT: @DEFAULT_LOGFILED@
3293 LOC: Log::TheConfig.logfile_daemon
3295 Specify the path to the logfile-writing daemon. This daemon is
3296 used to write the access and store logs, if configured.
3298 Squid sends a number of commands to the log daemon:
3299 L<data>\n - logfile data
3304 r<n>\n - set rotate count to <n>
3305 b<n>\n - 1 = buffer output, 0 = don't buffer output
3307 No responses is expected.
3312 LOC: Config.accessList.log
3314 COMMENT: allow|deny acl acl...
3316 This options allows you to control which requests gets logged
3317 to access.log (see access_log directive). Requests denied for
3318 logging will also not be accounted for in performance counters.
3320 This clause only supports fast acl types.
3321 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
3327 LOC: Config.accessList.icap
3330 This options allows you to control which requests get logged
3331 to icap.log. See the icap_log directive for ICAP log details.
3334 NAME: cache_store_log
3337 LOC: Config.Log.store
3339 Logs the activities of the storage manager. Shows which
3340 objects are ejected from the cache, and which objects are
3341 saved and for how long. To disable, enter "none" or remove the line.
3342 There are not really utilities to analyze this data, so you can safely
3346 cache_store_log @DEFAULT_STORE_LOG@
3349 NAME: cache_swap_state cache_swap_log
3351 LOC: Config.Log.swap
3354 Location for the cache "swap.state" file. This index file holds
3355 the metadata of objects saved on disk. It is used to rebuild
3356 the cache during startup. Normally this file resides in each
3357 'cache_dir' directory, but you may specify an alternate
3358 pathname here. Note you must give a full filename, not just
3359 a directory. Since this is the index for the whole object
3360 list you CANNOT periodically rotate it!
3362 If %s can be used in the file name it will be replaced with a
3363 a representation of the cache_dir name where each / is replaced
3364 with '.'. This is needed to allow adding/removing cache_dir
3365 lines when cache_swap_log is being used.
3367 If have more than one 'cache_dir', and %s is not used in the name
3368 these swap logs will have names such as:
3374 The numbered extension (which is added automatically)
3375 corresponds to the order of the 'cache_dir' lines in this
3376 configuration file. If you change the order of the 'cache_dir'
3377 lines in this file, these index files will NOT correspond to
3378 the correct 'cache_dir' entry (unless you manually rename
3379 them). We recommend you do NOT use this option. It is
3380 better to keep these index files in each 'cache_dir' directory.
3383 NAME: logfile_rotate
3386 LOC: Config.Log.rotateNumber
3388 Specifies the number of logfile rotations to make when you
3389 type 'squid -k rotate'. The default is 10, which will rotate
3390 with extensions 0 through 9. Setting logfile_rotate to 0 will
3391 disable the file name rotation, but the logfiles are still closed
3392 and re-opened. This will enable you to rename the logfiles
3393 yourself just before sending the rotate signal.
3395 Note, the 'squid -k rotate' command normally sends a USR1
3396 signal to the running squid process. In certain situations
3397 (e.g. on Linux with Async I/O), USR1 is used for other
3398 purposes, so -k rotate uses another signal. It is best to get
3399 in the habit of using 'squid -k rotate' instead of 'kill -USR1
3402 Note, from Squid-3.1 this option has no effect on the cache.log,
3403 that log can be rotated separately by using debug_options
3406 NAME: emulate_httpd_log
3409 Replace this with an access_log directive using the format 'common' or 'combined'.
3412 NAME: log_ip_on_direct
3415 Remove this option from your config. To log server or peer names use %<A in the log format.
3420 DEFAULT: @DEFAULT_MIME_TABLE@
3421 LOC: Config.mimeTablePathname
3423 Pathname to Squid's MIME table. You shouldn't need to change
3424 this, but the default file contains examples and formatting
3425 information if you do.
3431 LOC: Config.onoff.log_mime_hdrs
3434 The Cache can record both the request and the response MIME
3435 headers for each HTTP transaction. The headers are encoded
3436 safely and will appear as two bracketed fields at the end of
3437 the access log (for either the native or httpd-emulated log
3438 formats). To enable this logging set log_mime_hdrs to 'on'.
3444 Replace this with an access_log directive using the format 'useragent'.
3447 NAME: referer_log referrer_log
3450 Replace this with an access_log directive using the format 'referrer'.
3455 DEFAULT: @DEFAULT_PID_FILE@
3456 LOC: Config.pidFilename
3458 A filename to write the process-id to. To disable, enter "none".
3464 Remove this option from your config. To log FQDN use %>A in the log format.
3467 NAME: client_netmask
3469 LOC: Config.Addrs.client_netmask
3472 A netmask for client addresses in logfiles and cachemgr output.
3473 Change this to protect the privacy of your cache clients.
3474 A netmask of 255.255.255.0 will log all IP's in that range with
3475 the last digit set to '0'.
3481 Use a regular access.log with ACL limiting it to MISS events.
3484 NAME: strip_query_terms
3486 LOC: Config.onoff.strip_query_terms
3489 By default, Squid strips query terms from requested URLs before
3490 logging. This protects your user's privacy.
3497 LOC: Config.onoff.buffered_logs
3499 cache.log log file is written with stdio functions, and as such
3500 it can be buffered or unbuffered. By default it will be unbuffered.
3501 Buffering it can speed up the writing slightly (though you are
3502 unlikely to need to worry unless you run with tons of debugging
3503 enabled in which case performance will suffer badly anyway..).
3506 NAME: netdb_filename
3508 DEFAULT: stdio:@DEFAULT_NETDB_FILE@
3509 LOC: Config.netdbFilename
3512 A filename where Squid stores it's netdb state between restarts.
3513 To disable, enter "none".
3517 OPTIONS FOR TROUBLESHOOTING
3518 -----------------------------------------------------------------------------
3523 DEFAULT_IF_NONE: @DEFAULT_CACHE_LOG@
3524 LOC: Debug::cache_log
3526 Cache logging file. This is where general information about
3527 your cache's behavior goes. You can increase the amount of data
3528 logged to this file and how often its rotated with "debug_options"
3534 LOC: Debug::debugOptions
3536 Logging options are set as section,level where each source file
3537 is assigned a unique section. Lower levels result in less
3538 output, Full debugging (level 9) can result in a very large
3539 log file, so be careful.
3541 The magic word "ALL" sets debugging levels for all sections.
3542 We recommend normally running with "ALL,1".
3544 The rotate=N option can be used to keep more or less of these logs
3545 than would otherwise be kept by logfile_rotate.
3546 For most uses a single log should be enough to monitor current
3547 events affecting Squid.
3552 LOC: Config.coredump_dir
3553 DEFAULT_IF_NONE: none
3555 By default Squid leaves core files in the directory from where
3556 it was started. If you set 'coredump_dir' to a directory
3557 that exists, Squid will chdir() to that directory at startup
3558 and coredump files will be left there.
3562 # Leave coredumps in the first cache dir
3563 coredump_dir @DEFAULT_SWAP_DIR@
3569 OPTIONS FOR FTP GATEWAYING
3570 -----------------------------------------------------------------------------
3576 LOC: Config.Ftp.anon_user
3578 If you want the anonymous login password to be more informative
3579 (and enable the use of picky ftp servers), set this to something
3580 reasonable for your domain, like wwwuser@somewhere.net
3582 The reason why this is domainless by default is the
3583 request can be made on the behalf of a user in any domain,
3584 depending on how the cache is used.
3585 Some ftp server also validate the email address is valid
3586 (for example perl.com).
3592 LOC: Config.Ftp.passive
3594 If your firewall does not allow Squid to use passive
3595 connections, turn off this option.
3597 Use of ftp_epsv_all option requires this to be ON.
3603 LOC: Config.Ftp.epsv_all
3605 FTP Protocol extensions permit the use of a special "EPSV ALL" command.
3607 NATs may be able to put the connection on a "fast path" through the
3608 translator, as the EPRT command will never be used and therefore,
3609 translation of the data portion of the segments will never be needed.
3611 When a client only expects to do two-way FTP transfers this may be
3613 If squid finds that it must do a three-way FTP transfer after issuing
3614 an EPSV ALL command, the FTP session will fail.
3616 If you have any doubts about this option do not use it.
3617 Squid will nicely attempt all other connection methods.
3619 Requires ftp_passive to be ON (default) for any effect.
3625 LOC: Config.Ftp.epsv
3627 FTP Protocol extensions permit the use of a special "EPSV" command.
3629 NATs may be able to put the connection on a "fast path" through the
3630 translator using EPSV, as the EPRT command will never be used
3631 and therefore, translation of the data portion of the segments
3632 will never be needed.
3634 Turning this OFF will prevent EPSV being attempted.
3635 WARNING: Doing so will convert Squid back to the old behavior with all
3636 the related problems with external NAT devices/layers.
3638 Requires ftp_passive to be ON (default) for any effect.
3644 LOC: Config.Ftp.eprt
3646 FTP Protocol extensions permit the use of a special "EPRT" command.
3648 This extension provides a protocol neutral alternative to the
3649 IPv4-only PORT command. When supported it enables active FTP data
3650 channels over IPv6 and efficient NAT handling.
3652 Turning this OFF will prevent EPRT being attempted and will skip
3653 straight to using PORT for IPv4 servers.
3655 Some devices are known to not handle this extension correctly and
3656 may result in crashes. Devices which suport EPRT enough to fail
3657 cleanly will result in Squid attempting PORT anyway. This directive
3658 should only be disabled when EPRT results in device failures.
3660 WARNING: Doing so will convert Squid back to the old behavior with all
3661 the related problems with external NAT devices/layers and IPv4-only FTP.
3664 NAME: ftp_sanitycheck
3667 LOC: Config.Ftp.sanitycheck
3669 For security and data integrity reasons Squid by default performs
3670 sanity checks of the addresses of FTP data connections ensure the
3671 data connection is to the requested server. If you need to allow
3672 FTP connections to servers using another IP address for the data
3673 connection turn this off.
3676 NAME: ftp_telnet_protocol
3679 LOC: Config.Ftp.telnet
3681 The FTP protocol is officially defined to use the telnet protocol
3682 as transport channel for the control connection. However, many
3683 implementations are broken and does not respect this aspect of
3686 If you have trouble accessing files with ASCII code 255 in the
3687 path or similar problems involving this ASCII code you can
3688 try setting this directive to off. If that helps, report to the
3689 operator of the FTP server in question that their FTP server
3690 is broken and does not follow the FTP standard.
3694 OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
3695 -----------------------------------------------------------------------------
3700 DEFAULT: @DEFAULT_DISKD@
3701 LOC: Config.Program.diskd
3703 Specify the location of the diskd executable.
3704 Note this is only useful if you have compiled in
3705 diskd as one of the store io modules.
3708 NAME: unlinkd_program
3711 DEFAULT: @DEFAULT_UNLINKD@
3712 LOC: Config.Program.unlinkd
3714 Specify the location of the executable for file deletion process.
3717 NAME: pinger_program
3719 DEFAULT: @DEFAULT_PINGER@
3720 LOC: Config.pinger.program
3723 Specify the location of the executable for the pinger process.
3729 LOC: Config.pinger.enable
3732 Control whether the pinger is active at run-time.
3733 Enables turning ICMP pinger on and off with a simple
3734 squid -k reconfigure.
3739 OPTIONS FOR URL REWRITING
3740 -----------------------------------------------------------------------------
3743 NAME: url_rewrite_program redirect_program
3745 LOC: Config.Program.redirect
3748 Specify the location of the executable URL rewriter to use.
3749 Since they can perform almost any function there isn't one included.
3751 For each requested URL, the rewriter will receive on line with the format
3753 URL <SP> client_ip "/" fqdn <SP> user <SP> method [<SP> kvpairs]<NL>
3755 In the future, the rewriter interface will be extended with
3756 key=value pairs ("kvpairs" shown above). Rewriter programs
3757 should be prepared to receive and possibly ignore additional
3758 whitespace-separated tokens on each input line.
3760 And the rewriter may return a rewritten URL. The other components of
3761 the request line does not need to be returned (ignored if they are).
3763 The rewriter can also indicate that a client-side redirect should
3764 be performed to the new URL. This is done by prefixing the returned
3765 URL with "301:" (moved permanently) or 302: (moved temporarily), etc.
3767 By default, a URL rewriter is not used.
3770 NAME: url_rewrite_children redirect_children
3771 TYPE: HelperChildConfig
3772 DEFAULT: 20 startup=0 idle=1 concurrency=0
3773 LOC: Config.redirectChildren
3775 The maximum number of redirector processes to spawn. If you limit
3776 it too few Squid will have to wait for them to process a backlog of
3777 URLs, slowing it down. If you allow too many they will use RAM
3778 and other system resources noticably.
3780 The startup= and idle= options allow some measure of skew in your
3785 Sets a minimum of how many processes are to be spawned when Squid
3786 starts or reconfigures. When set to zero the first request will
3787 cause spawning of the first child process to handle it.
3789 Starting too few will cause an initial slowdown in traffic as Squid
3790 attempts to simultaneously spawn enough processes to cope.
3794 Sets a minimum of how many processes Squid is to try and keep available
3795 at all times. When traffic begins to rise above what the existing
3796 processes can handle this many more will be spawned up to the maximum
3797 configured. A minimum setting of 1 is required.
3801 The number of requests each redirector helper can handle in
3802 parallel. Defaults to 0 which indicates the redirector
3803 is a old-style single threaded redirector.
3805 When this directive is set to a value >= 1 then the protocol
3806 used to communicate with the helper is modified to include
3807 a request ID in front of the request/response. The request
3808 ID from the request must be echoed back with the response
3812 NAME: url_rewrite_host_header redirect_rewrites_host_header
3815 LOC: Config.onoff.redir_rewrites_host
3817 To preserve same-origin security policies in browsers and
3818 prevent Host: header forgery by redirectors Squid rewrites
3819 any Host: header in redirected requests.
3821 If you are running an accelerator this may not be a wanted
3822 effect of a redirector. This directive enables you disable
3823 Host: alteration in reverse-proxy traffic.
3825 WARNING: Entries are cached on the result of the URL rewriting
3826 process, so be careful if you have domain-virtual hosts.
3828 WARNING: Squid and other software verifies the URL and Host
3829 are matching, so be careful not to relay through other proxies
3830 or inspecting firewalls with this disabled.
3833 NAME: url_rewrite_access redirector_access
3836 LOC: Config.accessList.redirector
3838 If defined, this access list specifies which requests are
3839 sent to the redirector processes. By default all requests
3842 This clause supports both fast and slow acl types.
3843 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
3846 NAME: url_rewrite_bypass redirector_bypass
3848 LOC: Config.onoff.redirector_bypass
3851 When this is 'on', a request will not go through the
3852 redirector if all redirectors are busy. If this is 'off'
3853 and the redirector queue grows too large, Squid will exit
3854 with a FATAL error and ask you to increase the number of
3855 redirectors. You should only enable this if the redirectors
3856 are not critical to your caching system. If you use
3857 redirectors for access control, and you enable this option,
3858 users may have access to pages they should not
3859 be allowed to request.
3863 OPTIONS FOR TUNING THE CACHE
3864 -----------------------------------------------------------------------------
3867 NAME: cache no_cache
3870 LOC: Config.accessList.noCache
3872 A list of ACL elements which, if matched and denied, cause the request to
3873 not be satisfied from the cache and the reply to not be cached.
3874 In other words, use this to force certain objects to never be cached.
3876 You must use the words 'allow' or 'deny' to indicate whether items
3877 matching the ACL should be allowed or denied into the cache.
3879 Default is to allow all to be cached.
3881 This clause supports both fast and slow acl types.
3882 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
3888 LOC: Config.maxStale
3891 This option puts an upper limit on how stale content Squid
3892 will serve from the cache if cache validation fails.
3893 Can be overriden by the refresh_pattern max-stale option.
3896 NAME: refresh_pattern
3897 TYPE: refreshpattern
3901 usage: refresh_pattern [-i] regex min percent max [options]
3903 By default, regular expressions are CASE-SENSITIVE. To make
3904 them case-insensitive, use the -i option.
3906 'Min' is the time (in minutes) an object without an explicit
3907 expiry time should be considered fresh. The recommended
3908 value is 0, any higher values may cause dynamic applications
3909 to be erroneously cached unless the application designer
3910 has taken the appropriate actions.
3912 'Percent' is a percentage of the objects age (time since last
3913 modification age) an object without explicit expiry time
3914 will be considered fresh.
3916 'Max' is an upper limit on how long objects without an explicit
3917 expiry time will be considered fresh.
3919 options: override-expire
3925 ignore-must-revalidate
3932 override-expire enforces min age even if the server
3933 sent an explicit expiry time (e.g., with the
3934 Expires: header or Cache-Control: max-age). Doing this
3935 VIOLATES the HTTP standard. Enabling this feature
3936 could make you liable for problems which it causes.
3938 Note: override-expire does not enforce staleness - it only extends
3939 freshness / min. If the server returns a Expires time which
3940 is longer than your max time, Squid will still consider
3941 the object fresh for that period of time.
3943 override-lastmod enforces min age even on objects
3944 that were modified recently.
3946 reload-into-ims changes client no-cache or ``reload''
3947 to If-Modified-Since requests. Doing this VIOLATES the
3948 HTTP standard. Enabling this feature could make you
3949 liable for problems which it causes.
3951 ignore-reload ignores a client no-cache or ``reload''
3952 header. Doing this VIOLATES the HTTP standard. Enabling
3953 this feature could make you liable for problems which
3956 ignore-no-cache ignores any ``Pragma: no-cache'' and
3957 ``Cache-control: no-cache'' headers received from a server.
3958 The HTTP RFC never allows the use of this (Pragma) header
3959 from a server, only a client, though plenty of servers
3962 ignore-no-store ignores any ``Cache-control: no-store''
3963 headers received from a server. Doing this VIOLATES
3964 the HTTP standard. Enabling this feature could make you
3965 liable for problems which it causes.
3967 ignore-must-revalidate ignores any ``Cache-Control: must-revalidate``
3968 headers received from a server. Doing this VIOLATES
3969 the HTTP standard. Enabling this feature could make you
3970 liable for problems which it causes.
3972 ignore-private ignores any ``Cache-control: private''
3973 headers received from a server. Doing this VIOLATES
3974 the HTTP standard. Enabling this feature could make you
3975 liable for problems which it causes.
3977 ignore-auth caches responses to requests with authorization,
3978 as if the originserver had sent ``Cache-control: public''
3979 in the response header. Doing this VIOLATES the HTTP standard.
3980 Enabling this feature could make you liable for problems which
3983 refresh-ims causes squid to contact the origin server
3984 when a client issues an If-Modified-Since request. This
3985 ensures that the client will receive an updated version
3986 if one is available.
3988 store-stale stores responses even if they don't have explicit
3989 freshness or a validator (i.e., Last-Modified or an ETag)
3990 present, or if they're already stale. By default, Squid will
3991 not cache such responses because they usually can't be
3992 reused. Note that such responses will be stale by default.
3994 max-stale=NN provide a maximum staleness factor. Squid won't
3995 serve objects more stale than this even if it failed to
3996 validate the object. Default: use the max_stale global limit.
3998 Basically a cached object is:
4000 FRESH if expires < now, else STALE
4002 FRESH if lm-factor < percent, else STALE
4006 The refresh_pattern lines are checked in the order listed here.
4007 The first entry which matches is used. If none of the entries
4008 match the default will be used.
4010 Note, you must uncomment all the default lines if you want
4011 to change one. The default setting is only active if none is
4016 # Add any of your own refresh_pattern entries above these.
4017 refresh_pattern ^ftp: 1440 20% 10080
4018 refresh_pattern ^gopher: 1440 0% 1440
4019 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0
4020 refresh_pattern . 0 20% 4320
4024 NAME: quick_abort_min
4028 LOC: Config.quickAbort.min
4031 NAME: quick_abort_max
4035 LOC: Config.quickAbort.max
4038 NAME: quick_abort_pct
4042 LOC: Config.quickAbort.pct
4044 The cache by default continues downloading aborted requests
4045 which are almost completed (less than 16 KB remaining). This
4046 may be undesirable on slow (e.g. SLIP) links and/or very busy
4047 caches. Impatient users may tie up file descriptors and
4048 bandwidth by repeatedly requesting and immediately aborting
4051 When the user aborts a request, Squid will check the
4052 quick_abort values to the amount of data transfered until
4055 If the transfer has less than 'quick_abort_min' KB remaining,
4056 it will finish the retrieval.
4058 If the transfer has more than 'quick_abort_max' KB remaining,
4059 it will abort the retrieval.
4061 If more than 'quick_abort_pct' of the transfer has completed,
4062 it will finish the retrieval.
4064 If you do not want any retrieval to continue after the client
4065 has aborted, set both 'quick_abort_min' and 'quick_abort_max'
4068 If you want retrievals to always continue if they are being
4069 cached set 'quick_abort_min' to '-1 KB'.
4072 NAME: read_ahead_gap
4073 COMMENT: buffer-size
4075 LOC: Config.readAheadGap
4078 The amount of data the cache will buffer ahead of what has been
4079 sent to the client when retrieving an object from another server.
4083 IFDEF: USE_HTTP_VIOLATIONS
4086 LOC: Config.negativeTtl
4089 Set the Default Time-to-Live (TTL) for failed requests.
4090 Certain types of failures (such as "connection refused" and
4091 "404 Not Found") are able to be negatively-cached for a short time.
4092 Modern web servers should provide Expires: header, however if they
4093 do not this can provide a minimum TTL.
4094 The default is not to cache errors with unknown expiry details.
4096 Note that this is different from negative caching of DNS lookups.
4098 WARNING: Doing this VIOLATES the HTTP standard. Enabling
4099 this feature could make you liable for problems which it
4103 NAME: positive_dns_ttl
4106 LOC: Config.positiveDnsTtl
4109 Upper limit on how long Squid will cache positive DNS responses.
4110 Default is 6 hours (360 minutes). This directive must be set
4111 larger than negative_dns_ttl.
4114 NAME: negative_dns_ttl
4117 LOC: Config.negativeDnsTtl
4120 Time-to-Live (TTL) for negative caching of failed DNS lookups.
4121 This also sets the lower cache limit on positive lookups.
4122 Minimum value is 1 second, and it is not recommendable to go
4123 much below 10 seconds.
4126 NAME: range_offset_limit
4127 COMMENT: size [acl acl...]
4129 LOC: Config.rangeOffsetLimit
4132 usage: (size) [units] [[!]aclname]
4134 Sets an upper limit on how far (number of bytes) into the file
4135 a Range request may be to cause Squid to prefetch the whole file.
4136 If beyond this limit, Squid forwards the Range request as it is and
4137 the result is NOT cached.
4139 This is to stop a far ahead range request (lets say start at 17MB)
4140 from making Squid fetch the whole object up to that point before
4141 sending anything to the client.
4143 Multiple range_offset_limit lines may be specified, and they will
4144 be searched from top to bottom on each request until a match is found.
4145 The first match found will be used. If no line matches a request, the
4146 default limit of 0 bytes will be used.
4148 'size' is the limit specified as a number of units.
4150 'units' specifies whether to use bytes, KB, MB, etc.
4151 If no units are specified bytes are assumed.
4153 A size of 0 causes Squid to never fetch more than the
4154 client requested. (default)
4156 A size of 'none' causes Squid to always fetch the object from the
4157 beginning so it may cache the result. (2.0 style)
4159 'aclname' is the name of a defined ACL.
4161 NP: Using 'none' as the byte value here will override any quick_abort settings
4162 that may otherwise apply to the range request. The range request will
4163 be fully fetched from start to finish regardless of the client
4164 actions. This affects bandwidth usage.
4167 NAME: minimum_expiry_time
4170 LOC: Config.minimum_expiry_time
4173 The minimum caching time according to (Expires - Date)
4174 Headers Squid honors if the object can't be revalidated
4175 defaults to 60 seconds. In reverse proxy environments it
4176 might be desirable to honor shorter object lifetimes. It
4177 is most likely better to make your server return a
4178 meaningful Last-Modified header however. In ESI environments
4179 where page fragments often have short lifetimes, this will
4180 often be best set to 0.
4183 NAME: store_avg_object_size
4187 LOC: Config.Store.avgObjectSize
4189 Average object size, used to estimate number of objects your
4190 cache can hold. The default is 13 KB.
4193 NAME: store_objects_per_bucket
4196 LOC: Config.Store.objectsPerBucket
4198 Target number of objects per bucket in the store hash table.
4199 Lowering this value increases the total number of buckets and
4200 also the storage maintenance rate. The default is 20.
4205 -----------------------------------------------------------------------------
4208 NAME: request_header_max_size
4212 LOC: Config.maxRequestHeaderSize
4214 This specifies the maximum size for HTTP headers in a request.
4215 Request headers are usually relatively small (about 512 bytes).
4216 Placing a limit on the request header size will catch certain
4217 bugs (for example with persistent connections) and possibly
4218 buffer-overflow or denial-of-service attacks.
4221 NAME: reply_header_max_size
4225 LOC: Config.maxReplyHeaderSize
4227 This specifies the maximum size for HTTP headers in a reply.
4228 Reply headers are usually relatively small (about 512 bytes).
4229 Placing a limit on the reply header size will catch certain
4230 bugs (for example with persistent connections) and possibly
4231 buffer-overflow or denial-of-service attacks.
4234 NAME: request_body_max_size
4238 LOC: Config.maxRequestBodySize
4240 This specifies the maximum size for an HTTP request body.
4241 In other words, the maximum size of a PUT/POST request.
4242 A user who attempts to send a request with a body larger
4243 than this limit receives an "Invalid Request" error message.
4244 If you set this parameter to a zero (the default), there will
4245 be no limit imposed.
4248 NAME: client_request_buffer_max_size
4252 LOC: Config.maxRequestBufferSize
4254 This specifies the maximum buffer size of a client request.
4255 It prevents squid eating too much memory when somebody uploads
4259 NAME: chunked_request_body_max_size
4263 LOC: Config.maxChunkedRequestBodySize
4265 A broken or confused HTTP/1.1 client may send a chunked HTTP
4266 request to Squid. Squid does not have full support for that
4267 feature yet. To cope with such requests, Squid buffers the
4268 entire request and then dechunks request body to create a
4269 plain HTTP/1.0 request with a known content length. The plain
4270 request is then used by the rest of Squid code as usual.
4272 The option value specifies the maximum size of the buffer used
4273 to hold the request before the conversion. If the chunked
4274 request size exceeds the specified limit, the conversion
4275 fails, and the client receives an "unsupported request" error,
4276 as if dechunking was disabled.
4278 Dechunking is enabled by default. To disable conversion of
4279 chunked requests, set the maximum to zero.
4281 Request dechunking feature and this option in particular are a
4282 temporary hack. When chunking requests and responses are fully
4283 supported, there will be no need to buffer a chunked request.
4287 IFDEF: USE_HTTP_VIOLATIONS
4290 LOC: Config.accessList.brokenPosts
4292 A list of ACL elements which, if matched, causes Squid to send
4293 an extra CRLF pair after the body of a PUT/POST request.
4295 Some HTTP servers has broken implementations of PUT/POST,
4296 and rely on an extra CRLF pair sent by some WWW clients.
4298 Quote from RFC2616 section 4.1 on this matter:
4300 Note: certain buggy HTTP/1.0 client implementations generate an
4301 extra CRLF's after a POST request. To restate what is explicitly
4302 forbidden by the BNF, an HTTP/1.1 client must not preface or follow
4303 a request with an extra CRLF.
4305 This clause only supports fast acl types.
4306 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4309 acl buggy_server url_regex ^http://....
4310 broken_posts allow buggy_server
4313 NAME: adaptation_uses_indirect_client icap_uses_indirect_client
4316 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_ADAPTATION
4318 LOC: Adaptation::Config::use_indirect_client
4320 Controls whether the indirect client IP address (instead of the direct
4321 client IP address) is passed to adaptation services.
4323 See also: follow_x_forwarded_for adaptation_send_client_ip
4327 IFDEF: USE_HTTP_VIOLATIONS
4331 LOC: Config.onoff.via
4333 If set (default), Squid will include a Via header in requests and
4334 replies as required by RFC2616.
4340 LOC: Config.onoff.ie_refresh
4343 Microsoft Internet Explorer up until version 5.5 Service
4344 Pack 1 has an issue with transparent proxies, wherein it
4345 is impossible to force a refresh. Turning this on provides
4346 a partial fix to the problem, by causing all IMS-REFRESH
4347 requests from older IE versions to check the origin server
4348 for fresh content. This reduces hit ratio by some amount
4349 (~10% in my experience), but allows users to actually get
4350 fresh content when they want it. Note because Squid
4351 cannot tell if the user is using 5.5 or 5.5SP1, the behavior
4352 of 5.5 is unchanged from old versions of Squid (i.e. a
4353 forced refresh is impossible). Newer versions of IE will,
4354 hopefully, continue to have the new behavior and will be
4355 handled based on that assumption. This option defaults to
4356 the old Squid behavior, which is better for hit ratios but
4357 worse for clients using IE, if they need to be able to
4358 force fresh content.
4361 NAME: vary_ignore_expire
4364 LOC: Config.onoff.vary_ignore_expire
4367 Many HTTP servers supporting Vary gives such objects
4368 immediate expiry time with no cache-control header
4369 when requested by a HTTP/1.0 client. This option
4370 enables Squid to ignore such expiry times until
4371 HTTP/1.1 is fully implemented.
4373 WARNING: If turned on this may eventually cause some
4374 varying objects not intended for caching to get cached.
4377 NAME: request_entities
4379 LOC: Config.onoff.request_entities
4382 Squid defaults to deny GET and HEAD requests with request entities,
4383 as the meaning of such requests are undefined in the HTTP standard
4384 even if not explicitly forbidden.
4386 Set this directive to on if you have clients which insists
4387 on sending request entities in GET or HEAD requests. But be warned
4388 that there is server software (both proxies and web servers) which
4389 can fail to properly process this kind of request which may make you
4390 vulnerable to cache pollution attacks if enabled.
4393 NAME: request_header_access
4394 IFDEF: USE_HTTP_VIOLATIONS
4395 TYPE: http_header_access
4396 LOC: Config.request_header_access
4399 Usage: request_header_access header_name allow|deny [!]aclname ...
4401 WARNING: Doing this VIOLATES the HTTP standard. Enabling
4402 this feature could make you liable for problems which it
4405 This option replaces the old 'anonymize_headers' and the
4406 older 'http_anonymizer' option with something that is much
4407 more configurable. A list of ACLs for each header name allows
4408 removal of specific header fields under specific conditions.
4410 This option only applies to outgoing HTTP request headers (i.e.,
4411 headers sent by Squid to the next HTTP hop such as a cache peer
4412 or an origin server). The option has no effect during cache hit
4413 detection. The equivalent adaptation vectoring point in ICAP
4414 terminology is post-cache REQMOD.
4416 The option is applied to individual outgoing request header
4417 fields. For each request header field F, Squid uses the first
4418 qualifying sets of request_header_access rules:
4420 1. Rules with header_name equal to F's name.
4421 2. Rules with header_name 'Other', provided F's name is not
4422 on the hard-coded list of commonly used HTTP header names.
4423 3. Rules with header_name 'All'.
4425 Within that qualifying rule set, rule ACLs are checked as usual.
4426 If ACLs of an "allow" rule match, the header field is allowed to
4427 go through as is. If ACLs of a "deny" rule match, the header is
4428 removed and request_header_replace is then checked to identify
4429 if the removed header has a replacement. If no rules within the
4430 set have matching ACLs, the header field is left as is.
4432 For example, to achieve the same behavior as the old
4433 'http_anonymizer standard' option, you should use:
4435 request_header_access From deny all
4436 request_header_access Referer deny all
4437 request_header_access Server deny all
4438 request_header_access User-Agent deny all
4439 request_header_access WWW-Authenticate deny all
4440 request_header_access Link deny all
4442 Or, to reproduce the old 'http_anonymizer paranoid' feature
4445 request_header_access Allow allow all
4446 request_header_access Authorization allow all
4447 request_header_access WWW-Authenticate allow all
4448 request_header_access Proxy-Authorization allow all
4449 request_header_access Proxy-Authenticate allow all
4450 request_header_access Cache-Control allow all
4451 request_header_access Content-Encoding allow all
4452 request_header_access Content-Length allow all
4453 request_header_access Content-Type allow all
4454 request_header_access Date allow all
4455 request_header_access Expires allow all
4456 request_header_access Host allow all
4457 request_header_access If-Modified-Since allow all
4458 request_header_access Last-Modified allow all
4459 request_header_access Location allow all
4460 request_header_access Pragma allow all
4461 request_header_access Accept allow all
4462 request_header_access Accept-Charset allow all
4463 request_header_access Accept-Encoding allow all
4464 request_header_access Accept-Language allow all
4465 request_header_access Content-Language allow all
4466 request_header_access Mime-Version allow all
4467 request_header_access Retry-After allow all
4468 request_header_access Title allow all
4469 request_header_access Connection allow all
4470 request_header_access All deny all
4472 although many of those are HTTP reply headers, and so should be
4473 controlled with the reply_header_access directive.
4475 By default, all headers are allowed (no anonymizing is
4479 NAME: reply_header_access
4480 IFDEF: USE_HTTP_VIOLATIONS
4481 TYPE: http_header_access
4482 LOC: Config.reply_header_access
4485 Usage: reply_header_access header_name allow|deny [!]aclname ...
4487 WARNING: Doing this VIOLATES the HTTP standard. Enabling
4488 this feature could make you liable for problems which it
4491 This option only applies to reply headers, i.e., from the
4492 server to the client.
4494 This is the same as request_header_access, but in the other
4495 direction. Please see request_header_access for detailed
4498 For example, to achieve the same behavior as the old
4499 'http_anonymizer standard' option, you should use:
4501 reply_header_access From deny all
4502 reply_header_access Referer deny all
4503 reply_header_access Server deny all
4504 reply_header_access User-Agent deny all
4505 reply_header_access WWW-Authenticate deny all
4506 reply_header_access Link deny all
4508 Or, to reproduce the old 'http_anonymizer paranoid' feature
4511 reply_header_access Allow allow all
4512 reply_header_access Authorization allow all
4513 reply_header_access WWW-Authenticate allow all
4514 reply_header_access Proxy-Authorization allow all
4515 reply_header_access Proxy-Authenticate allow all
4516 reply_header_access Cache-Control allow all
4517 reply_header_access Content-Encoding allow all
4518 reply_header_access Content-Length allow all
4519 reply_header_access Content-Type allow all
4520 reply_header_access Date allow all
4521 reply_header_access Expires allow all
4522 reply_header_access Host allow all
4523 reply_header_access If-Modified-Since allow all
4524 reply_header_access Last-Modified allow all
4525 reply_header_access Location allow all
4526 reply_header_access Pragma allow all
4527 reply_header_access Accept allow all
4528 reply_header_access Accept-Charset allow all
4529 reply_header_access Accept-Encoding allow all
4530 reply_header_access Accept-Language allow all
4531 reply_header_access Content-Language allow all
4532 reply_header_access Mime-Version allow all
4533 reply_header_access Retry-After allow all
4534 reply_header_access Title allow all
4535 reply_header_access Connection allow all
4536 reply_header_access All deny all
4538 although the HTTP request headers won't be usefully controlled
4539 by this directive -- see request_header_access for details.
4541 By default, all headers are allowed (no anonymizing is
4545 NAME: request_header_replace header_replace
4546 IFDEF: USE_HTTP_VIOLATIONS
4547 TYPE: http_header_replace
4548 LOC: Config.request_header_access
4551 Usage: request_header_replace header_name message
4552 Example: request_header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
4554 This option allows you to change the contents of headers
4555 denied with request_header_access above, by replacing them
4556 with some fixed string. This replaces the old fake_user_agent
4559 This only applies to request headers, not reply headers.
4561 By default, headers are removed if denied.
4564 NAME: reply_header_replace
4565 IFDEF: USE_HTTP_VIOLATIONS
4566 TYPE: http_header_replace
4567 LOC: Config.reply_header_access
4570 Usage: reply_header_replace header_name message
4571 Example: reply_header_replace Server Foo/1.0
4573 This option allows you to change the contents of headers
4574 denied with reply_header_access above, by replacing them
4575 with some fixed string.
4577 This only applies to reply headers, not request headers.
4579 By default, headers are removed if denied.
4582 NAME: relaxed_header_parser
4583 COMMENT: on|off|warn
4585 LOC: Config.onoff.relaxed_header_parser
4588 In the default "on" setting Squid accepts certain forms
4589 of non-compliant HTTP messages where it is unambiguous
4590 what the sending application intended even if the message
4591 is not correctly formatted. The messages is then normalized
4592 to the correct form when forwarded by Squid.
4594 If set to "warn" then a warning will be emitted in cache.log
4595 each time such HTTP error is encountered.
4597 If set to "off" then such HTTP errors will cause the request
4598 or response to be rejected.
4603 -----------------------------------------------------------------------------
4606 NAME: forward_timeout
4609 LOC: Config.Timeout.forward
4612 This parameter specifies how long Squid should at most attempt in
4613 finding a forwarding path for the request before giving up.
4616 NAME: connect_timeout
4619 LOC: Config.Timeout.connect
4622 This parameter specifies how long to wait for the TCP connect to
4623 the requested server or peer to complete before Squid should
4624 attempt to find another path where to forward the request.
4627 NAME: peer_connect_timeout
4630 LOC: Config.Timeout.peer_connect
4633 This parameter specifies how long to wait for a pending TCP
4634 connection to a peer cache. The default is 30 seconds. You
4635 may also set different timeout values for individual neighbors
4636 with the 'connect-timeout' option on a 'cache_peer' line.
4642 LOC: Config.Timeout.read
4645 The read_timeout is applied on server-side connections. After
4646 each successful read(), the timeout will be extended by this
4647 amount. If no data is read again after this amount of time,
4648 the request is aborted and logged with ERR_READ_TIMEOUT. The
4649 default is 15 minutes.
4655 LOC: Config.Timeout.write
4658 This timeout is tracked for all connections that have data
4659 available for writing and are waiting for the socket to become
4660 ready. After each successful write, the timeout is extended by
4661 the configured amount. If Squid has data to write but the
4662 connection is not ready for the configured duration, the
4663 transaction associated with the connection is terminated. The
4664 default is 15 minutes.
4667 NAME: request_timeout
4669 LOC: Config.Timeout.request
4672 How long to wait for complete HTTP request headers after initial
4673 connection establishment.
4676 NAME: client_idle_pconn_timeout persistent_request_timeout
4678 LOC: Config.Timeout.clientIdlePconn
4681 How long to wait for the next HTTP request on a persistent
4682 client connection after the previous request completes.
4685 NAME: client_lifetime
4688 LOC: Config.Timeout.lifetime
4691 The maximum amount of time a client (browser) is allowed to
4692 remain connected to the cache process. This protects the Cache
4693 from having a lot of sockets (and hence file descriptors) tied up
4694 in a CLOSE_WAIT state from remote clients that go away without
4695 properly shutting down (either because of a network failure or
4696 because of a poor client implementation). The default is one
4699 NOTE: The default value is intended to be much larger than any
4700 client would ever need to be connected to your cache. You
4701 should probably change client_lifetime only as a last resort.
4702 If you seem to have many client connections tying up
4703 filedescriptors, we recommend first tuning the read_timeout,
4704 request_timeout, persistent_request_timeout and quick_abort values.
4707 NAME: half_closed_clients
4709 LOC: Config.onoff.half_closed_clients
4712 Some clients may shutdown the sending side of their TCP
4713 connections, while leaving their receiving sides open. Sometimes,
4714 Squid can not tell the difference between a half-closed and a
4715 fully-closed TCP connection.
4717 By default, Squid will immediately close client connections when
4718 read(2) returns "no more data to read."
4720 Change this option to 'on' and Squid will keep open connections
4721 until a read(2) or write(2) on the socket returns an error.
4722 This may show some benefits for reverse proxies. But if not
4723 it is recommended to leave OFF.
4726 NAME: server_idle_pconn_timeout pconn_timeout
4728 LOC: Config.Timeout.serverIdlePconn
4731 Timeout for idle persistent connections to servers and other
4738 LOC: Ident::TheConfig.timeout
4741 Maximum time to wait for IDENT lookups to complete.
4743 If this is too high, and you enabled IDENT lookups from untrusted
4744 users, you might be susceptible to denial-of-service by having
4745 many ident requests going at once.
4748 NAME: shutdown_lifetime
4751 LOC: Config.shutdownLifetime
4754 When SIGTERM or SIGHUP is received, the cache is put into
4755 "shutdown pending" mode until all active sockets are closed.
4756 This value is the lifetime to set for all open descriptors
4757 during shutdown mode. Any active clients after this many
4758 seconds will receive a 'timeout' message.
4762 ADMINISTRATIVE PARAMETERS
4763 -----------------------------------------------------------------------------
4769 LOC: Config.adminEmail
4771 Email-address of local cache manager who will receive
4772 mail if the cache dies. The default is "webmaster."
4778 LOC: Config.EmailFrom
4780 From: email-address for mail sent when the cache dies.
4781 The default is to use 'appname@unique_hostname'.
4782 Default appname value is "squid", can be changed into
4783 src/globals.h before building squid.
4789 LOC: Config.EmailProgram
4791 Email program used to send mail if the cache dies.
4792 The default is "mail". The specified program must comply
4793 with the standard Unix mail syntax:
4794 mail-program recipient < mailfile
4796 Optional command line options can be specified.
4799 NAME: cache_effective_user
4801 DEFAULT: @DEFAULT_CACHE_EFFECTIVE_USER@
4802 LOC: Config.effectiveUser
4804 If you start Squid as root, it will change its effective/real
4805 UID/GID to the user specified below. The default is to change
4806 to UID of @DEFAULT_CACHE_EFFECTIVE_USER@.
4807 see also; cache_effective_group
4810 NAME: cache_effective_group
4813 LOC: Config.effectiveGroup
4815 Squid sets the GID to the effective user's default group ID
4816 (taken from the password file) and supplementary group list
4817 from the groups membership.
4819 If you want Squid to run with a specific GID regardless of
4820 the group memberships of the effective user then set this
4821 to the group (or GID) you want Squid to run as. When set
4822 all other group privileges of the effective user are ignored
4823 and only this GID is effective. If Squid is not started as
4824 root the user starting Squid MUST be member of the specified
4827 This option is not recommended by the Squid Team.
4828 Our preference is for administrators to configure a secure
4829 user account for squid with UID/GID matching system policies.
4832 NAME: httpd_suppress_version_string
4836 LOC: Config.onoff.httpd_suppress_version_string
4838 Suppress Squid version string info in HTTP headers and HTML error pages.
4841 NAME: visible_hostname
4843 LOC: Config.visibleHostname
4846 If you want to present a special hostname in error messages, etc,
4847 define this. Otherwise, the return value of gethostname()
4848 will be used. If you have multiple caches in a cluster and
4849 get errors about IP-forwarding you must set them to have individual
4850 names with this setting.
4853 NAME: unique_hostname
4855 LOC: Config.uniqueHostname
4858 If you want to have multiple machines with the same
4859 'visible_hostname' you must give each machine a different
4860 'unique_hostname' so forwarding loops can be detected.
4863 NAME: hostname_aliases
4865 LOC: Config.hostnameAliases
4868 A list of other DNS names your cache has.
4876 Minimum umask which should be enforced while the proxy
4877 is running, in addition to the umask set at startup.
4879 For a traditional octal representation of umasks, start
4884 OPTIONS FOR THE CACHE REGISTRATION SERVICE
4885 -----------------------------------------------------------------------------
4887 This section contains parameters for the (optional) cache
4888 announcement service. This service is provided to help
4889 cache administrators locate one another in order to join or
4890 create cache hierarchies.
4892 An 'announcement' message is sent (via UDP) to the registration
4893 service by Squid. By default, the announcement message is NOT
4894 SENT unless you enable it with 'announce_period' below.
4896 The announcement message includes your hostname, plus the
4897 following information from this configuration file:
4903 All current information is processed regularly and made
4904 available on the Web at http://www.ircache.net/Cache/Tracker/.
4907 NAME: announce_period
4909 LOC: Config.Announce.period
4912 This is how frequently to send cache announcements. The
4913 default is `0' which disables sending the announcement
4916 To enable announcing your cache, just set an announce period.
4919 announce_period 1 day
4924 DEFAULT: tracker.ircache.net
4925 LOC: Config.Announce.host
4931 LOC: Config.Announce.file
4937 LOC: Config.Announce.port
4939 announce_host and announce_port set the hostname and port
4940 number where the registration message will be sent.
4942 Hostname will default to 'tracker.ircache.net' and port will
4943 default default to 3131. If the 'filename' argument is given,
4944 the contents of that file will be included in the announce
4949 HTTPD-ACCELERATOR OPTIONS
4950 -----------------------------------------------------------------------------
4953 NAME: httpd_accel_surrogate_id
4956 LOC: Config.Accel.surrogate_id
4958 Surrogates (http://www.esi.org/architecture_spec_1.0.html)
4959 need an identification token to allow control targeting. Because
4960 a farm of surrogates may all perform the same tasks, they may share
4961 an identification token.
4963 The default ID is the visible_hostname
4966 NAME: http_accel_surrogate_remote
4970 LOC: Config.onoff.surrogate_is_remote
4972 Remote surrogates (such as those in a CDN) honour Surrogate-Control: no-store-remote.
4973 Set this to on to have squid behave as a remote surrogate.
4977 IFDEF: USE_SQUID_ESI
4978 COMMENT: libxml2|expat|custom
4980 LOC: ESIParser::Type
4983 ESI markup is not strictly XML compatible. The custom ESI parser
4984 will give higher performance, but cannot handle non ASCII character
4989 DELAY POOL PARAMETERS
4990 -----------------------------------------------------------------------------
4994 TYPE: delay_pool_count
4996 IFDEF: USE_DELAY_POOLS
4999 This represents the number of delay pools to be used. For example,
5000 if you have one class 2 delay pool and one class 3 delays pool, you
5001 have a total of 2 delay pools.
5005 TYPE: delay_pool_class
5007 IFDEF: USE_DELAY_POOLS
5010 This defines the class of each delay pool. There must be exactly one
5011 delay_class line for each delay pool. For example, to define two
5012 delay pools, one of class 2 and one of class 3, the settings above
5016 delay_pools 4 # 4 delay pools
5017 delay_class 1 2 # pool 1 is a class 2 pool
5018 delay_class 2 3 # pool 2 is a class 3 pool
5019 delay_class 3 4 # pool 3 is a class 4 pool
5020 delay_class 4 5 # pool 4 is a class 5 pool
5022 The delay pool classes are:
5024 class 1 Everything is limited by a single aggregate
5027 class 2 Everything is limited by a single aggregate
5028 bucket as well as an "individual" bucket chosen
5029 from bits 25 through 32 of the IPv4 address.
5031 class 3 Everything is limited by a single aggregate
5032 bucket as well as a "network" bucket chosen
5033 from bits 17 through 24 of the IP address and a
5034 "individual" bucket chosen from bits 17 through
5035 32 of the IPv4 address.
5037 class 4 Everything in a class 3 delay pool, with an
5038 additional limit on a per user basis. This
5039 only takes effect if the username is established
5040 in advance - by forcing authentication in your
5043 class 5 Requests are grouped according their tag (see
5044 external_acl's tag= reply).
5047 Each pool also requires a delay_parameters directive to configure the pool size
5048 and speed limits used whenever the pool is applied to a request. Along with
5049 a set of delay_access directives to determine when it is used.
5051 NOTE: If an IP address is a.b.c.d
5052 -> bits 25 through 32 are "d"
5053 -> bits 17 through 24 are "c"
5054 -> bits 17 through 32 are "c * 256 + d"
5056 NOTE-2: Due to the use of bitmasks in class 2,3,4 pools they only apply to
5057 IPv4 traffic. Class 1 and 5 pools may be used with IPv6 traffic.
5061 TYPE: delay_pool_access
5063 IFDEF: USE_DELAY_POOLS
5066 This is used to determine which delay pool a request falls into.
5068 delay_access is sorted per pool and the matching starts with pool 1,
5069 then pool 2, ..., and finally pool N. The first delay pool where the
5070 request is allowed is selected for the request. If it does not allow
5071 the request to any pool then the request is not delayed (default).
5073 For example, if you want some_big_clients in delay
5074 pool 1 and lotsa_little_clients in delay pool 2:
5077 delay_access 1 allow some_big_clients
5078 delay_access 1 deny all
5079 delay_access 2 allow lotsa_little_clients
5080 delay_access 2 deny all
5081 delay_access 3 allow authenticated_clients
5084 NAME: delay_parameters
5085 TYPE: delay_pool_rates
5087 IFDEF: USE_DELAY_POOLS
5090 This defines the parameters for a delay pool. Each delay pool has
5091 a number of "buckets" associated with it, as explained in the
5092 description of delay_class.
5094 For a class 1 delay pool, the syntax is:
5096 delay_parameters pool aggregate
5098 For a class 2 delay pool:
5100 delay_parameters pool aggregate individual
5102 For a class 3 delay pool:
5104 delay_parameters pool aggregate network individual
5106 For a class 4 delay pool:
5108 delay_parameters pool aggregate network individual user
5110 For a class 5 delay pool:
5112 delay_parameters pool tagrate
5114 The option variables are:
5116 pool a pool number - ie, a number between 1 and the
5117 number specified in delay_pools as used in
5120 aggregate the speed limit parameters for the aggregate bucket
5123 individual the speed limit parameters for the individual
5124 buckets (class 2, 3).
5126 network the speed limit parameters for the network buckets
5129 user the speed limit parameters for the user buckets
5132 tagrate the speed limit parameters for the tag buckets
5135 A pair of delay parameters is written restore/maximum, where restore is
5136 the number of bytes (not bits - modem and network speeds are usually
5137 quoted in bits) per second placed into the bucket, and maximum is the
5138 maximum number of bytes which can be in the bucket at any time.
5140 There must be one delay_parameters line for each delay pool.
5143 For example, if delay pool number 1 is a class 2 delay pool as in the
5144 above example, and is being used to strictly limit each host to 64Kbit/sec
5145 (plus overheads), with no overall limit, the line is:
5147 delay_parameters 1 -1/-1 8000/8000
5149 Note that 8 x 8000 KByte/sec -> 64Kbit/sec.
5151 Note that the figure -1 is used to represent "unlimited".
5154 And, if delay pool number 2 is a class 3 delay pool as in the above
5155 example, and you want to limit it to a total of 256Kbit/sec (strict limit)
5156 with each 8-bit network permitted 64Kbit/sec (strict limit) and each
5157 individual host permitted 4800bit/sec with a bucket maximum size of 64Kbits
5158 to permit a decent web page to be downloaded at a decent speed
5159 (if the network is not being limited due to overuse) but slow down
5160 large downloads more significantly:
5162 delay_parameters 2 32000/32000 8000/8000 600/8000
5164 Note that 8 x 32000 KByte/sec -> 256Kbit/sec.
5165 8 x 8000 KByte/sec -> 64Kbit/sec.
5166 8 x 600 Byte/sec -> 4800bit/sec.
5169 Finally, for a class 4 delay pool as in the example - each user will
5170 be limited to 128Kbits/sec no matter how many workstations they are logged into.:
5172 delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000
5175 NAME: delay_initial_bucket_level
5176 COMMENT: (percent, 0-100)
5179 IFDEF: USE_DELAY_POOLS
5180 LOC: Config.Delay.initial
5182 The initial bucket percentage is used to determine how much is put
5183 in each bucket when squid starts, is reconfigured, or first notices
5184 a host accessing it (in class 2 and class 3, individual hosts and
5185 networks only have buckets associated with them once they have been
5190 CLIENT DELAY POOL PARAMETERS
5191 -----------------------------------------------------------------------------
5194 NAME: client_delay_pools
5195 TYPE: client_delay_pool_count
5197 IFDEF: USE_DELAY_POOLS
5198 LOC: Config.ClientDelay
5200 This option specifies the number of client delay pools used. It must
5201 preceed other client_delay_* options.
5204 client_delay_pools 2
5207 NAME: client_delay_initial_bucket_level
5208 COMMENT: (percent, 0-no_limit)
5211 IFDEF: USE_DELAY_POOLS
5212 LOC: Config.ClientDelay.initial
5214 This option determines the initial bucket size as a percentage of
5215 max_bucket_size from client_delay_parameters. Buckets are created
5216 at the time of the "first" connection from the matching IP. Idle
5217 buckets are periodically deleted up.
5219 You can specify more than 100 percent but note that such "oversized"
5220 buckets are not refilled until their size goes down to max_bucket_size
5221 from client_delay_parameters.
5224 client_delay_initial_bucket_level 50
5227 NAME: client_delay_parameters
5228 TYPE: client_delay_pool_rates
5230 IFDEF: USE_DELAY_POOLS
5231 LOC: Config.ClientDelay
5234 This option configures client-side bandwidth limits using the
5237 client_delay_parameters pool speed_limit max_bucket_size
5239 pool is an integer ID used for client_delay_access matching.
5241 speed_limit is bytes added to the bucket per second.
5243 max_bucket_size is the maximum size of a bucket, enforced after any
5244 speed_limit additions.
5246 Please see the delay_parameters option for more information and
5250 client_delay_parameters 1 1024 2048
5251 client_delay_parameters 2 51200 16384
5254 NAME: client_delay_access
5255 TYPE: client_delay_pool_access
5257 IFDEF: USE_DELAY_POOLS
5258 LOC: Config.ClientDelay
5261 This option determines the client-side delay pool for the
5264 client_delay_access pool_ID allow|deny acl_name
5266 All client_delay_access options are checked in their pool ID
5267 order, starting with pool 1. The first checked pool with allowed
5268 request is selected for the request. If no ACL matches or there
5269 are no client_delay_access options, the request bandwidth is not
5272 The ACL-selected pool is then used to find the
5273 client_delay_parameters for the request. Client-side pools are
5274 not used to aggregate clients. Clients are always aggregated
5275 based on their source IP addresses (one bucket per source IP).
5277 Please see delay_access for more examples.
5280 client_delay_access 1 allow low_rate_network
5281 client_delay_access 2 allow vips_network
5285 WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS
5286 -----------------------------------------------------------------------------
5291 LOC: Config.Wccp.router
5295 Use this option to define your WCCP ``home'' router for
5298 wccp_router supports a single WCCP(v1) router
5300 wccp2_router supports multiple WCCPv2 routers
5302 only one of the two may be used at the same time and defines
5303 which version of WCCP to use.
5307 TYPE: IpAddress_list
5308 LOC: Config.Wccp2.router
5312 Use this option to define your WCCP ``home'' router for
5315 wccp_router supports a single WCCP(v1) router
5317 wccp2_router supports multiple WCCPv2 routers
5319 only one of the two may be used at the same time and defines
5320 which version of WCCP to use.
5325 LOC: Config.Wccp.version
5329 This directive is only relevant if you need to set up WCCP(v1)
5330 to some very old and end-of-life Cisco routers. In all other
5331 setups it must be left unset or at the default setting.
5332 It defines an internal version in the WCCP(v1) protocol,
5333 with version 4 being the officially documented protocol.
5335 According to some users, Cisco IOS 11.2 and earlier only
5336 support WCCP version 3. If you're using that or an earlier
5337 version of IOS, you may need to change this value to 3, otherwise
5338 do not specify this parameter.
5341 NAME: wccp2_rebuild_wait
5343 LOC: Config.Wccp2.rebuildwait
5347 If this is enabled Squid will wait for the cache dir rebuild to finish
5348 before sending the first wccp2 HereIAm packet
5351 NAME: wccp2_forwarding_method
5353 LOC: Config.Wccp2.forwarding_method
5357 WCCP2 allows the setting of forwarding methods between the
5358 router/switch and the cache. Valid values are as follows:
5360 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
5361 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
5363 Currently (as of IOS 12.4) cisco routers only support GRE.
5364 Cisco switches only support the L2 redirect assignment method.
5367 NAME: wccp2_return_method
5369 LOC: Config.Wccp2.return_method
5373 WCCP2 allows the setting of return methods between the
5374 router/switch and the cache for packets that the cache
5375 decides not to handle. Valid values are as follows:
5377 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
5378 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
5380 Currently (as of IOS 12.4) cisco routers only support GRE.
5381 Cisco switches only support the L2 redirect assignment.
5383 If the "ip wccp redirect exclude in" command has been
5384 enabled on the cache interface, then it is still safe for
5385 the proxy server to use a l2 redirect method even if this
5386 option is set to GRE.
5389 NAME: wccp2_assignment_method
5391 LOC: Config.Wccp2.assignment_method
5395 WCCP2 allows the setting of methods to assign the WCCP hash
5396 Valid values are as follows:
5398 hash - Hash assignment
5399 mask - Mask assignment
5401 As a general rule, cisco routers support the hash assignment method
5402 and cisco switches support the mask assignment method.
5407 LOC: Config.Wccp2.info
5408 DEFAULT_IF_NONE: standard 0
5411 WCCP2 allows for multiple traffic services. There are two
5412 types: "standard" and "dynamic". The standard type defines
5413 one service id - http (id 0). The dynamic service ids can be from
5414 51 to 255 inclusive. In order to use a dynamic service id
5415 one must define the type of traffic to be redirected; this is done
5416 using the wccp2_service_info option.
5418 The "standard" type does not require a wccp2_service_info option,
5419 just specifying the service id will suffice.
5421 MD5 service authentication can be enabled by adding
5422 "password=<password>" to the end of this service declaration.
5426 wccp2_service standard 0 # for the 'web-cache' standard service
5427 wccp2_service dynamic 80 # a dynamic service type which will be
5428 # fleshed out with subsequent options.
5429 wccp2_service standard 0 password=foo
5432 NAME: wccp2_service_info
5433 TYPE: wccp2_service_info
5434 LOC: Config.Wccp2.info
5438 Dynamic WCCPv2 services require further information to define the
5439 traffic you wish to have diverted.
5443 wccp2_service_info <id> protocol=<protocol> flags=<flag>,<flag>..
5444 priority=<priority> ports=<port>,<port>..
5446 The relevant WCCPv2 flags:
5447 + src_ip_hash, dst_ip_hash
5448 + source_port_hash, dst_port_hash
5449 + src_ip_alt_hash, dst_ip_alt_hash
5450 + src_port_alt_hash, dst_port_alt_hash
5453 The port list can be one to eight entries.
5457 wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source
5458 priority=240 ports=80
5460 Note: the service id must have been defined by a previous
5461 'wccp2_service dynamic <id>' entry.
5466 LOC: Config.Wccp2.weight
5470 Each cache server gets assigned a set of the destination
5471 hash proportional to their weight.
5476 LOC: Config.Wccp.address
5483 LOC: Config.Wccp2.address
5487 Use this option if you require WCCP to use a specific
5490 The default behavior is to not bind to any specific address.
5494 PERSISTENT CONNECTION HANDLING
5495 -----------------------------------------------------------------------------
5497 Also see "pconn_timeout" in the TIMEOUTS section
5500 NAME: client_persistent_connections
5502 LOC: Config.onoff.client_pconns
5506 NAME: server_persistent_connections
5508 LOC: Config.onoff.server_pconns
5511 Persistent connection support for clients and servers. By
5512 default, Squid uses persistent connections (when allowed)
5513 with its clients and servers. You can use these options to
5514 disable persistent connections with clients and/or servers.
5517 NAME: persistent_connection_after_error
5519 LOC: Config.onoff.error_pconns
5522 With this directive the use of persistent connections after
5523 HTTP errors can be disabled. Useful if you have clients
5524 who fail to handle errors on persistent connections proper.
5527 NAME: detect_broken_pconn
5529 LOC: Config.onoff.detect_broken_server_pconns
5532 Some servers have been found to incorrectly signal the use
5533 of HTTP/1.0 persistent connections even on replies not
5534 compatible, causing significant delays. This server problem
5535 has mostly been seen on redirects.
5537 By enabling this directive Squid attempts to detect such
5538 broken replies and automatically assume the reply is finished
5539 after 10 seconds timeout.
5543 CACHE DIGEST OPTIONS
5544 -----------------------------------------------------------------------------
5547 NAME: digest_generation
5548 IFDEF: USE_CACHE_DIGESTS
5550 LOC: Config.onoff.digest_generation
5553 This controls whether the server will generate a Cache Digest
5554 of its contents. By default, Cache Digest generation is
5555 enabled if Squid is compiled with --enable-cache-digests defined.
5558 NAME: digest_bits_per_entry
5559 IFDEF: USE_CACHE_DIGESTS
5561 LOC: Config.digest.bits_per_entry
5564 This is the number of bits of the server's Cache Digest which
5565 will be associated with the Digest entry for a given HTTP
5566 Method and URL (public key) combination. The default is 5.
5569 NAME: digest_rebuild_period
5570 IFDEF: USE_CACHE_DIGESTS
5573 LOC: Config.digest.rebuild_period
5576 This is the wait time between Cache Digest rebuilds.
5579 NAME: digest_rewrite_period
5581 IFDEF: USE_CACHE_DIGESTS
5583 LOC: Config.digest.rewrite_period
5586 This is the wait time between Cache Digest writes to
5590 NAME: digest_swapout_chunk_size
5593 IFDEF: USE_CACHE_DIGESTS
5594 LOC: Config.digest.swapout_chunk_size
5597 This is the number of bytes of the Cache Digest to write to
5598 disk at a time. It defaults to 4096 bytes (4KB), the Squid
5602 NAME: digest_rebuild_chunk_percentage
5603 COMMENT: (percent, 0-100)
5604 IFDEF: USE_CACHE_DIGESTS
5606 LOC: Config.digest.rebuild_chunk_percentage
5609 This is the percentage of the Cache Digest to be scanned at a
5610 time. By default it is set to 10% of the Cache Digest.
5615 -----------------------------------------------------------------------------
5620 LOC: Config.Port.snmp
5624 The port number where Squid listens for SNMP requests. To enable
5625 SNMP support set this to a suitable port number. Port number
5626 3401 is often used for the Squid SNMP agent. By default it's
5627 set to "0" (disabled)
5635 LOC: Config.accessList.snmp
5636 DEFAULT_IF_NONE: deny all
5639 Allowing or denying access to the SNMP port.
5641 All access to the agent is denied by default.
5644 snmp_access allow|deny [!]aclname ...
5646 This clause only supports fast acl types.
5647 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5649 snmp_access allow snmppublic localhost
5650 snmp_access deny all
5653 NAME: snmp_incoming_address
5655 LOC: Config.Addrs.snmp_incoming
5660 NAME: snmp_outgoing_address
5662 LOC: Config.Addrs.snmp_outgoing
5666 Just like 'udp_incoming_address', but for the SNMP port.
5668 snmp_incoming_address is used for the SNMP socket receiving
5669 messages from SNMP agents.
5670 snmp_outgoing_address is used for SNMP packets returned to SNMP
5673 The default snmp_incoming_address is to listen on all
5674 available network interfaces.
5676 If snmp_outgoing_address is not set it will use the same socket
5677 as snmp_incoming_address. Only change this if you want to have
5678 SNMP replies sent using another address than where this Squid
5679 listens for SNMP queries.
5681 NOTE, snmp_incoming_address and snmp_outgoing_address can not have
5682 the same value since they both use port 3401.
5687 -----------------------------------------------------------------------------
5690 NAME: icp_port udp_port
5693 LOC: Config.Port.icp
5695 The port number where Squid sends and receives ICP queries to
5696 and from neighbor caches. The standard UDP port for ICP is 3130.
5697 Default is disabled (0).
5700 icp_port @DEFAULT_ICP_PORT@
5707 LOC: Config.Port.htcp
5709 The port number where Squid sends and receives HTCP queries to
5710 and from neighbor caches. To turn it on you want to set it to
5711 4827. By default it is set to "0" (disabled).
5717 NAME: log_icp_queries
5721 LOC: Config.onoff.log_udp
5723 If set, ICP queries are logged to access.log. You may wish
5724 do disable this if your ICP load is VERY high to speed things
5725 up or to simplify log analysis.
5728 NAME: udp_incoming_address
5730 LOC:Config.Addrs.udp_incoming
5733 udp_incoming_address is used for UDP packets received from other
5736 The default behavior is to not bind to any specific address.
5738 Only change this if you want to have all UDP queries received on
5739 a specific interface/address.
5741 NOTE: udp_incoming_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_outgoing_address
5746 NOTE, udp_incoming_address and udp_outgoing_address can not
5747 have the same value since they both use the same port.
5750 NAME: udp_outgoing_address
5752 LOC: Config.Addrs.udp_outgoing
5755 udp_outgoing_address is used for UDP packets sent out to other
5758 The default behavior is to not bind to any specific address.
5760 Instead it will use the same socket as udp_incoming_address.
5761 Only change this if you want to have UDP queries sent using another
5762 address than where this Squid listens for UDP queries from other
5765 NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS
5766 modules. Altering it will affect all of them in the same manner.
5768 see also; udp_incoming_address
5770 NOTE, udp_incoming_address and udp_outgoing_address can not
5771 have the same value since they both use the same port.
5778 LOC: Config.onoff.icp_hit_stale
5780 If you want to return ICP_HIT for stale cache objects, set this
5781 option to 'on'. If you have sibling relationships with caches
5782 in other administrative domains, this should be 'off'. If you only
5783 have sibling relationships with caches under your control,
5784 it is probably okay to set this to 'on'.
5785 If set to 'on', your siblings should use the option "allow-miss"
5786 on their cache_peer lines for connecting to you.
5789 NAME: minimum_direct_hops
5792 LOC: Config.minDirectHops
5794 If using the ICMP pinging stuff, do direct fetches for sites
5795 which are no more than this many hops away.
5798 NAME: minimum_direct_rtt
5801 LOC: Config.minDirectRtt
5803 If using the ICMP pinging stuff, do direct fetches for sites
5804 which are no more than this many rtt milliseconds away.
5810 LOC: Config.Netdb.low
5816 LOC: Config.Netdb.high
5818 The low and high water marks for the ICMP measurement
5819 database. These are counts, not percents. The defaults are
5820 900 and 1000. When the high water mark is reached, database
5821 entries will be deleted until the low mark is reached.
5824 NAME: netdb_ping_period
5826 LOC: Config.Netdb.period
5829 The minimum period for measuring a site. There will be at
5830 least this much delay between successive pings to the same
5831 network. The default is five minutes.
5838 LOC: Config.onoff.query_icmp
5840 If you want to ask your peers to include ICMP data in their ICP
5841 replies, enable this option.
5843 If your peer has configured Squid (during compilation) with
5844 '--enable-icmp' that peer will send ICMP pings to origin server
5845 sites of the URLs it receives. If you enable this option the
5846 ICP replies from that peer will include the ICMP data (if available).
5847 Then, when choosing a parent cache, Squid will choose the parent with
5848 the minimal RTT to the origin server. When this happens, the
5849 hierarchy field of the access.log will be
5850 "CLOSEST_PARENT_MISS". This option is off by default.
5853 NAME: test_reachability
5857 LOC: Config.onoff.test_reachability
5859 When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
5860 instead of ICP_MISS if the target host is NOT in the ICMP
5861 database, or has a zero RTT.
5864 NAME: icp_query_timeout
5868 LOC: Config.Timeout.icp_query
5870 Normally Squid will automatically determine an optimal ICP
5871 query timeout value based on the round-trip-time of recent ICP
5872 queries. If you want to override the value determined by
5873 Squid, set this 'icp_query_timeout' to a non-zero value. This
5874 value is specified in MILLISECONDS, so, to use a 2-second
5875 timeout (the old default), you would write:
5877 icp_query_timeout 2000
5880 NAME: maximum_icp_query_timeout
5884 LOC: Config.Timeout.icp_query_max
5886 Normally the ICP query timeout is determined dynamically. But
5887 sometimes it can lead to very large values (say 5 seconds).
5888 Use this option to put an upper limit on the dynamic timeout
5889 value. Do NOT use this option to always use a fixed (instead
5890 of a dynamic) timeout value. To set a fixed timeout see the
5891 'icp_query_timeout' directive.
5894 NAME: minimum_icp_query_timeout
5898 LOC: Config.Timeout.icp_query_min
5900 Normally the ICP query timeout is determined dynamically. But
5901 sometimes it can lead to very small timeouts, even lower than
5902 the normal latency variance on your link due to traffic.
5903 Use this option to put an lower limit on the dynamic timeout
5904 value. Do NOT use this option to always use a fixed (instead
5905 of a dynamic) timeout value. To set a fixed timeout see the
5906 'icp_query_timeout' directive.
5909 NAME: background_ping_rate
5913 LOC: Config.backgroundPingRate
5915 Controls how often the ICP pings are sent to siblings that
5916 have background-ping set.
5920 MULTICAST ICP OPTIONS
5921 -----------------------------------------------------------------------------
5926 LOC: Config.mcast_group_list
5929 This tag specifies a list of multicast groups which your server
5930 should join to receive multicasted ICP queries.
5932 NOTE! Be very careful what you put here! Be sure you
5933 understand the difference between an ICP _query_ and an ICP
5934 _reply_. This option is to be set only if you want to RECEIVE
5935 multicast queries. Do NOT set this option to SEND multicast
5936 ICP (use cache_peer for that). ICP replies are always sent via
5937 unicast, so this option does not affect whether or not you will
5938 receive replies from multicast group members.
5940 You must be very careful to NOT use a multicast address which
5941 is already in use by another group of caches.
5943 If you are unsure about multicast, please read the Multicast
5944 chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
5946 Usage: mcast_groups 239.128.16.128 224.0.1.20
5948 By default, Squid doesn't listen on any multicast groups.
5951 NAME: mcast_miss_addr
5952 IFDEF: MULTICAST_MISS_STREAM
5954 LOC: Config.mcast_miss.addr
5957 If you enable this option, every "cache miss" URL will
5958 be sent out on the specified multicast address.
5960 Do not enable this option unless you are are absolutely
5961 certain you understand what you are doing.
5964 NAME: mcast_miss_ttl
5965 IFDEF: MULTICAST_MISS_STREAM
5967 LOC: Config.mcast_miss.ttl
5970 This is the time-to-live value for packets multicasted
5971 when multicasting off cache miss URLs is enabled. By
5972 default this is set to 'site scope', i.e. 16.
5975 NAME: mcast_miss_port
5976 IFDEF: MULTICAST_MISS_STREAM
5978 LOC: Config.mcast_miss.port
5981 This is the port number to be used in conjunction with
5985 NAME: mcast_miss_encode_key
5986 IFDEF: MULTICAST_MISS_STREAM
5988 LOC: Config.mcast_miss.encode_key
5989 DEFAULT: XXXXXXXXXXXXXXXX
5991 The URLs that are sent in the multicast miss stream are
5992 encrypted. This is the encryption key.
5995 NAME: mcast_icp_query_timeout
5999 LOC: Config.Timeout.mcast_icp_query
6001 For multicast peers, Squid regularly sends out ICP "probes" to
6002 count how many other peers are listening on the given multicast
6003 address. This value specifies how long Squid should wait to
6004 count all the replies. The default is 2000 msec, or 2
6009 INTERNAL ICON OPTIONS
6010 -----------------------------------------------------------------------------
6013 NAME: icon_directory
6015 LOC: Config.icons.directory
6016 DEFAULT: @DEFAULT_ICON_DIR@
6018 Where the icons are stored. These are normally kept in
6022 NAME: global_internal_static
6024 LOC: Config.onoff.global_internal_static
6027 This directive controls is Squid should intercept all requests for
6028 /squid-internal-static/ no matter which host the URL is requesting
6029 (default on setting), or if nothing special should be done for
6030 such URLs (off setting). The purpose of this directive is to make
6031 icons etc work better in complex cache hierarchies where it may
6032 not always be possible for all corners in the cache mesh to reach
6033 the server generating a directory listing.
6036 NAME: short_icon_urls
6038 LOC: Config.icons.use_short_names
6041 If this is enabled Squid will use short URLs for icons.
6042 If disabled it will revert to the old behavior of including
6043 it's own name and port in the URL.
6045 If you run a complex cache hierarchy with a mix of Squid and
6046 other proxies you may need to disable this directive.
6051 -----------------------------------------------------------------------------
6054 NAME: error_directory
6056 LOC: Config.errorDirectory
6059 If you wish to create your own versions of the default
6060 error files to customize them to suit your company copy
6061 the error/template files to another directory and point
6064 WARNING: This option will disable multi-language support
6065 on error pages if used.
6067 The squid developers are interested in making squid available in
6068 a wide variety of languages. If you are making translations for a
6069 language that Squid does not currently provide please consider
6070 contributing your translation back to the project.
6071 http://wiki.squid-cache.org/Translations
6073 The squid developers working on translations are happy to supply drop-in
6074 translated error files in exchange for any new language contributions.
6077 NAME: error_default_language
6078 IFDEF: USE_ERR_LOCALES
6080 LOC: Config.errorDefaultLanguage
6083 Set the default language which squid will send error pages in
6084 if no existing translation matches the clients language
6087 If unset (default) generic English will be used.
6089 The squid developers are interested in making squid available in
6090 a wide variety of languages. If you are interested in making
6091 translations for any language see the squid wiki for details.
6092 http://wiki.squid-cache.org/Translations
6095 NAME: error_log_languages
6096 IFDEF: USE_ERR_LOCALES
6098 LOC: Config.errorLogMissingLanguages
6101 Log to cache.log what languages users are attempting to
6102 auto-negotiate for translations.
6104 Successful negotiations are not logged. Only failures
6105 have meaning to indicate that Squid may need an upgrade
6106 of its error page translations.
6109 NAME: err_page_stylesheet
6111 LOC: Config.errorStylesheet
6112 DEFAULT: @DEFAULT_CONFIG_DIR@/errorpage.css
6114 CSS Stylesheet to pattern the display of Squid default error pages.
6116 For information on CSS see http://www.w3.org/Style/CSS/
6121 LOC: Config.errHtmlText
6124 HTML text to include in error messages. Make this a "mailto"
6125 URL to your admin address, or maybe just a link to your
6126 organizations Web page.
6128 To include this in your error messages, you must rewrite
6129 the error template files (found in the "errors" directory).
6130 Wherever you want the 'err_html_text' line to appear,
6131 insert a %L tag in the error template file.
6134 NAME: email_err_data
6137 LOC: Config.onoff.emailErrData
6140 If enabled, information about the occurred error will be
6141 included in the mailto links of the ERR pages (if %W is set)
6142 so that the email body contains the data.
6143 Syntax is <A HREF="mailto:%w%W">%w</A>
6148 LOC: Config.denyInfoList
6151 Usage: deny_info err_page_name acl
6152 or deny_info http://... acl
6153 or deny_info TCP_RESET acl
6155 This can be used to return a ERR_ page for requests which
6156 do not pass the 'http_access' rules. Squid remembers the last
6157 acl it evaluated in http_access, and if a 'deny_info' line exists
6158 for that ACL Squid returns a corresponding error page.
6160 The acl is typically the last acl on the http_access deny line which
6161 denied access. The exceptions to this rule are:
6162 - When Squid needs to request authentication credentials. It's then
6163 the first authentication related acl encountered
6164 - When none of the http_access lines matches. It's then the last
6165 acl processed on the last http_access line.
6166 - When the decision to deny access was made by an adaptation service,
6167 the acl name is the corresponding eCAP or ICAP service_name.
6169 NP: If providing your own custom error pages with error_directory
6170 you may also specify them by your custom file name:
6171 Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
6173 By defaut Squid will send "403 Forbidden". A different 4xx or 5xx
6174 may be specified by prefixing the file name with the code and a colon.
6175 e.g. 404:ERR_CUSTOM_ACCESS_DENIED
6177 Alternatively you can tell Squid to reset the TCP connection
6178 by specifying TCP_RESET.
6180 Or you can specify an error URL or URL pattern. The browsers will
6181 get redirected to the specified URL after formatting tags have
6182 been replaced. Redirect will be done with 302 or 307 according to
6183 HTTP/1.1 specs. A different 3xx code may be specified by prefixing
6184 the URL. e.g. 303:http://example.com/
6187 %a - username (if available. Password NOT included)
6190 %E - Error description
6192 %H - Request domain name
6193 %i - Client IP Address
6195 %o - Message result from external ACL helper
6196 %p - Request Port number
6197 %P - Request Protocol name
6198 %R - Request URL path
6199 %T - Timestamp in RFC 1123 format
6200 %U - Full canonical URL from client
6201 (HTTPS URLs terminate with *)
6202 %u - Full canonical URL from client
6203 %w - Admin email from squid.conf
6205 %% - Literal percent (%) code
6210 OPTIONS INFLUENCING REQUEST FORWARDING
6211 -----------------------------------------------------------------------------
6214 NAME: nonhierarchical_direct
6216 LOC: Config.onoff.nonhierarchical_direct
6219 By default, Squid will send any non-hierarchical requests
6220 (matching hierarchy_stoplist or not cacheable request type) direct
6223 If you set this to off, Squid will prefer to send these
6224 requests to parents.
6226 Note that in most configurations, by turning this off you will only
6227 add latency to these request without any improvement in global hit
6230 If you are inside an firewall see never_direct instead of
6236 LOC: Config.onoff.prefer_direct
6239 Normally Squid tries to use parents for most requests. If you for some
6240 reason like it to first try going direct and only use a parent if
6241 going direct fails set this to on.
6243 By combining nonhierarchical_direct off and prefer_direct on you
6244 can set up Squid to use a parent as a backup path if going direct
6247 Note: If you want Squid to use parents for all requests see
6248 the never_direct directive. prefer_direct only modifies how Squid
6249 acts on cacheable requests.
6254 LOC: Config.accessList.AlwaysDirect
6257 Usage: always_direct allow|deny [!]aclname ...
6259 Here you can use ACL elements to specify requests which should
6260 ALWAYS be forwarded by Squid to the origin servers without using
6261 any peers. For example, to always directly forward requests for
6262 local servers ignoring any parents or siblings you may have use
6265 acl local-servers dstdomain my.domain.net
6266 always_direct allow local-servers
6268 To always forward FTP requests directly, use
6271 always_direct allow FTP
6273 NOTE: There is a similar, but opposite option named
6274 'never_direct'. You need to be aware that "always_direct deny
6275 foo" is NOT the same thing as "never_direct allow foo". You
6276 may need to use a deny rule to exclude a more-specific case of
6277 some other rule. Example:
6279 acl local-external dstdomain external.foo.net
6280 acl local-servers dstdomain .foo.net
6281 always_direct deny local-external
6282 always_direct allow local-servers
6284 NOTE: If your goal is to make the client forward the request
6285 directly to the origin server bypassing Squid then this needs
6286 to be done in the client configuration. Squid configuration
6287 can only tell Squid how Squid should fetch the object.
6289 NOTE: This directive is not related to caching. The replies
6290 is cached as usual even if you use always_direct. To not cache
6291 the replies see the 'cache' directive.
6293 This clause supports both fast and slow acl types.
6294 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6299 LOC: Config.accessList.NeverDirect
6302 Usage: never_direct allow|deny [!]aclname ...
6304 never_direct is the opposite of always_direct. Please read
6305 the description for always_direct if you have not already.
6307 With 'never_direct' you can use ACL elements to specify
6308 requests which should NEVER be forwarded directly to origin
6309 servers. For example, to force the use of a proxy for all
6310 requests, except those in your local domain use something like:
6312 acl local-servers dstdomain .foo.net
6313 never_direct deny local-servers
6314 never_direct allow all
6316 or if Squid is inside a firewall and there are local intranet
6317 servers inside the firewall use something like:
6319 acl local-intranet dstdomain .foo.net
6320 acl local-external dstdomain external.foo.net
6321 always_direct deny local-external
6322 always_direct allow local-intranet
6323 never_direct allow all
6325 This clause supports both fast and slow acl types.
6326 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6330 ADVANCED NETWORKING OPTIONS
6331 -----------------------------------------------------------------------------
6334 NAME: incoming_udp_average incoming_icp_average
6337 LOC: Config.comm_incoming.udp.average
6339 Heavy voodoo here. I can't even believe you are reading this.
6340 Are you crazy? Don't even think about adjusting these unless
6341 you understand the algorithms in comm_select.c first!
6344 NAME: incoming_tcp_average incoming_http_average
6347 LOC: Config.comm_incoming.tcp.average
6349 Heavy voodoo here. I can't even believe you are reading this.
6350 Are you crazy? Don't even think about adjusting these unless
6351 you understand the algorithms in comm_select.c first!
6354 NAME: incoming_dns_average
6357 LOC: Config.comm_incoming.dns.average
6359 Heavy voodoo here. I can't even believe you are reading this.
6360 Are you crazy? Don't even think about adjusting these unless
6361 you understand the algorithms in comm_select.c first!
6364 NAME: min_udp_poll_cnt min_icp_poll_cnt
6367 LOC: Config.comm_incoming.udp.min_poll
6369 Heavy voodoo here. I can't even believe you are reading this.
6370 Are you crazy? Don't even think about adjusting these unless
6371 you understand the algorithms in comm_select.c first!
6374 NAME: min_dns_poll_cnt
6377 LOC: Config.comm_incoming.dns.min_poll
6379 Heavy voodoo here. I can't even believe you are reading this.
6380 Are you crazy? Don't even think about adjusting these unless
6381 you understand the algorithms in comm_select.c first!
6384 NAME: min_tcp_poll_cnt min_http_poll_cnt
6387 LOC: Config.comm_incoming.tcp.min_poll
6389 Heavy voodoo here. I can't even believe you are reading this.
6390 Are you crazy? Don't even think about adjusting these unless
6391 you understand the algorithms in comm_select.c first!
6397 LOC: Config.accept_filter
6401 The name of an accept(2) filter to install on Squid's
6402 listen socket(s). This feature is perhaps specific to
6403 FreeBSD and requires support in the kernel.
6405 The 'httpready' filter delays delivering new connections
6406 to Squid until a full HTTP request has been received.
6407 See the accf_http(9) man page for details.
6409 The 'dataready' filter delays delivering new connections
6410 to Squid until there is some data to process.
6411 See the accf_dataready(9) man page for details.
6415 The 'data' filter delays delivering of new connections
6416 to Squid until there is some data to process by TCP_ACCEPT_DEFER.
6417 You may optionally specify a number of seconds to wait by
6418 'data=N' where N is the number of seconds. Defaults to 30
6419 if not specified. See the tcp(7) man page for details.
6422 accept_filter httpready
6427 NAME: client_ip_max_connections
6429 LOC: Config.client_ip_max_connections
6432 Set an absolute limit on the number of connections a single
6433 client IP can use. Any more than this and Squid will begin to drop
6434 new connections from the client until it closes some links.
6436 Note that this is a global limit. It affects all HTTP, HTCP, Gopher and FTP
6437 connections from the client. For finer control use the ACL access controls.
6439 Requires client_db to be enabled (the default).
6441 WARNING: This may noticably slow down traffic received via external proxies
6442 or NAT devices and cause them to rebound error messages back to their clients.
6445 NAME: tcp_recv_bufsize
6449 LOC: Config.tcpRcvBufsz
6451 Size of receive buffer to set for TCP sockets. Probably just
6452 as easy to change your kernel's default. Set to zero to use
6453 the default buffer size.
6458 -----------------------------------------------------------------------------
6465 LOC: Adaptation::Icap::TheConfig.onoff
6468 If you want to enable the ICAP module support, set this to on.
6471 NAME: icap_connect_timeout
6474 LOC: Adaptation::Icap::TheConfig.connect_timeout_raw
6477 This parameter specifies how long to wait for the TCP connect to
6478 the requested ICAP server to complete before giving up and either
6479 terminating the HTTP transaction or bypassing the failure.
6481 The default for optional services is peer_connect_timeout.
6482 The default for essential services is connect_timeout.
6483 If this option is explicitly set, its value applies to all services.
6486 NAME: icap_io_timeout
6490 LOC: Adaptation::Icap::TheConfig.io_timeout_raw
6493 This parameter specifies how long to wait for an I/O activity on
6494 an established, active ICAP connection before giving up and
6495 either terminating the HTTP transaction or bypassing the
6498 The default is read_timeout.
6501 NAME: icap_service_failure_limit
6502 COMMENT: limit [in memory-depth time-units]
6503 TYPE: icap_service_failure_limit
6505 LOC: Adaptation::Icap::TheConfig
6508 The limit specifies the number of failures that Squid tolerates
6509 when establishing a new TCP connection with an ICAP service. If
6510 the number of failures exceeds the limit, the ICAP service is
6511 not used for new ICAP requests until it is time to refresh its
6514 A negative value disables the limit. Without the limit, an ICAP
6515 service will not be considered down due to connectivity failures
6516 between ICAP OPTIONS requests.
6518 Squid forgets ICAP service failures older than the specified
6519 value of memory-depth. The memory fading algorithm
6520 is approximate because Squid does not remember individual
6521 errors but groups them instead, splitting the option
6522 value into ten time slots of equal length.
6524 When memory-depth is 0 and by default this option has no
6525 effect on service failure expiration.
6527 Squid always forgets failures when updating service settings
6528 using an ICAP OPTIONS transaction, regardless of this option
6532 # suspend service usage after 10 failures in 5 seconds:
6533 icap_service_failure_limit 10 in 5 seconds
6536 NAME: icap_service_revival_delay
6539 LOC: Adaptation::Icap::TheConfig.service_revival_delay
6542 The delay specifies the number of seconds to wait after an ICAP
6543 OPTIONS request failure before requesting the options again. The
6544 failed ICAP service is considered "down" until fresh OPTIONS are
6547 The actual delay cannot be smaller than the hardcoded minimum
6548 delay of 30 seconds.
6551 NAME: icap_preview_enable
6555 LOC: Adaptation::Icap::TheConfig.preview_enable
6558 The ICAP Preview feature allows the ICAP server to handle the
6559 HTTP message by looking only at the beginning of the message body
6560 or even without receiving the body at all. In some environments,
6561 previews greatly speedup ICAP processing.
6563 During an ICAP OPTIONS transaction, the server may tell Squid what
6564 HTTP messages should be previewed and how big the preview should be.
6565 Squid will not use Preview if the server did not request one.
6567 To disable ICAP Preview for all ICAP services, regardless of
6568 individual ICAP server OPTIONS responses, set this option to "off".
6570 icap_preview_enable off
6573 NAME: icap_preview_size
6576 LOC: Adaptation::Icap::TheConfig.preview_size
6579 The default size of preview data to be sent to the ICAP server.
6580 -1 means no preview. This value might be overwritten on a per server
6581 basis by OPTIONS requests.
6584 NAME: icap_206_enable
6588 LOC: Adaptation::Icap::TheConfig.allow206_enable
6591 206 (Partial Content) responses is an ICAP extension that allows the
6592 ICAP agents to optionally combine adapted and original HTTP message
6593 content. The decision to combine is postponed until the end of the
6594 ICAP response. Squid supports Partial Content extension by default.
6596 Activation of the Partial Content extension is negotiated with each
6597 ICAP service during OPTIONS exchange. Most ICAP servers should handle
6598 negotation correctly even if they do not support the extension, but
6599 some might fail. To disable Partial Content support for all ICAP
6600 services and to avoid any negotiation, set this option to "off".
6606 NAME: icap_default_options_ttl
6609 LOC: Adaptation::Icap::TheConfig.default_options_ttl
6612 The default TTL value for ICAP OPTIONS responses that don't have
6613 an Options-TTL header.
6616 NAME: icap_persistent_connections
6620 LOC: Adaptation::Icap::TheConfig.reuse_connections
6623 Whether or not Squid should use persistent connections to
6627 NAME: adaptation_send_client_ip icap_send_client_ip
6629 IFDEF: USE_ADAPTATION
6631 LOC: Adaptation::Config::send_client_ip
6634 If enabled, Squid shares HTTP client IP information with adaptation
6635 services. For ICAP, Squid adds the X-Client-IP header to ICAP requests.
6636 For eCAP, Squid sets the libecap::metaClientIp transaction option.
6638 See also: adaptation_uses_indirect_client
6641 NAME: adaptation_send_username icap_send_client_username
6643 IFDEF: USE_ADAPTATION
6645 LOC: Adaptation::Config::send_username
6648 This sends authenticated HTTP client username (if available) to
6649 the adaptation service.
6651 For ICAP, the username value is encoded based on the
6652 icap_client_username_encode option and is sent using the header
6653 specified by the icap_client_username_header option.
6656 NAME: icap_client_username_header
6659 LOC: Adaptation::Icap::TheConfig.client_username_header
6660 DEFAULT: X-Client-Username
6662 ICAP request header name to use for adaptation_send_username.
6665 NAME: icap_client_username_encode
6669 LOC: Adaptation::Icap::TheConfig.client_username_encode
6672 Whether to base64 encode the authenticated client username.
6676 TYPE: icap_service_type
6678 LOC: Adaptation::Icap::TheConfig
6681 Defines a single ICAP service using the following format:
6683 icap_service id vectoring_point uri [option ...]
6686 an opaque identifier or name which is used to direct traffic to
6687 this specific service. Must be unique among all adaptation
6688 services in squid.conf.
6690 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
6691 This specifies at which point of transaction processing the
6692 ICAP service should be activated. *_postcache vectoring points
6693 are not yet supported.
6695 uri: icap://servername:port/servicepath
6696 ICAP server and service location.
6698 ICAP does not allow a single service to handle both REQMOD and RESPMOD
6699 transactions. Squid does not enforce that requirement. You can specify
6700 services with the same service_url and different vectoring_points. You
6701 can even specify multiple identical services as long as their
6702 service_names differ.
6705 Service options are separated by white space. ICAP services support
6706 the following name=value options:
6709 If set to 'on' or '1', the ICAP service is treated as
6710 optional. If the service cannot be reached or malfunctions,
6711 Squid will try to ignore any errors and process the message as
6712 if the service was not enabled. No all ICAP errors can be
6713 bypassed. If set to 0, the ICAP service is treated as
6714 essential and all ICAP errors will result in an error page
6715 returned to the HTTP client.
6717 Bypass is off by default: services are treated as essential.
6720 If set to 'on' or '1', the ICAP service is allowed to
6721 dynamically change the current message adaptation plan by
6722 returning a chain of services to be used next. The services
6723 are specified using the X-Next-Services ICAP response header
6724 value, formatted as a comma-separated list of service names.
6725 Each named service should be configured in squid.conf. Other
6726 services are ignored. An empty X-Next-Services value results
6727 in an empty plan which ends the current adaptation.
6729 Dynamic adaptation plan may cross or cover multiple supported
6730 vectoring points in their natural processing order.
6732 Routing is not allowed by default: the ICAP X-Next-Services
6733 response header is ignored.
6736 Only has effect on split-stack systems. The default on those systems
6737 is to use IPv4-only connections. When set to 'on' this option will
6738 make Squid use IPv6-only connections to contact this ICAP service.
6740 on-overload=block|bypass|wait|force
6741 If the service Max-Connections limit has been reached, do
6742 one of the following for each new ICAP transaction:
6743 * block: send an HTTP error response to the client
6744 * bypass: ignore the "over-connected" ICAP service
6745 * wait: wait (in a FIFO queue) for an ICAP connection slot
6746 * force: proceed, ignoring the Max-Connections limit
6748 In SMP mode with N workers, each worker assumes the service
6749 connection limit is Max-Connections/N, even though not all
6750 workers may use a given service.
6752 The default value is "bypass" if service is bypassable,
6753 otherwise it is set to "wait".
6757 Use the given number as the Max-Connections limit, regardless
6758 of the Max-Connections value given by the service, if any.
6760 Older icap_service format without optional named parameters is
6761 deprecated but supported for backward compatibility.
6764 icap_service svcBlocker reqmod_precache icap://icap1.mydomain.net:1344/reqmod bypass=0
6765 icap_service svcLogger reqmod_precache icap://icap2.mydomain.net:1344/respmod routing=on
6769 TYPE: icap_class_type
6774 This deprecated option was documented to define an ICAP service
6775 chain, even though it actually defined a set of similar, redundant
6776 services, and the chains were not supported.
6778 To define a set of redundant services, please use the
6779 adaptation_service_set directive. For service chains, use
6780 adaptation_service_chain.
6784 TYPE: icap_access_type
6789 This option is deprecated. Please use adaptation_access, which
6790 has the same ICAP functionality, but comes with better
6791 documentation, and eCAP support.
6796 -----------------------------------------------------------------------------
6803 LOC: Adaptation::Ecap::TheConfig.onoff
6806 Controls whether eCAP support is enabled.
6810 TYPE: ecap_service_type
6812 LOC: Adaptation::Ecap::TheConfig
6815 Defines a single eCAP service
6817 ecap_service id vectoring_point uri [option ...]
6820 an opaque identifier or name which is used to direct traffic to
6821 this specific service. Must be unique among all adaptation
6822 services in squid.conf.
6824 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
6825 This specifies at which point of transaction processing the
6826 eCAP service should be activated. *_postcache vectoring points
6827 are not yet supported.
6829 uri: ecap://vendor/service_name?custom&cgi=style¶meters=optional
6830 Squid uses the eCAP service URI to match this configuration
6831 line with one of the dynamically loaded services. Each loaded
6832 eCAP service must have a unique URI. Obtain the right URI from
6833 the service provider.
6836 Service options are separated by white space. eCAP services support
6837 the following name=value options:
6840 If set to 'on' or '1', the eCAP service is treated as optional.
6841 If the service cannot be reached or malfunctions, Squid will try
6842 to ignore any errors and process the message as if the service
6843 was not enabled. No all eCAP errors can be bypassed.
6844 If set to 'off' or '0', the eCAP service is treated as essential
6845 and all eCAP errors will result in an error page returned to the
6848 Bypass is off by default: services are treated as essential.
6851 If set to 'on' or '1', the eCAP service is allowed to
6852 dynamically change the current message adaptation plan by
6853 returning a chain of services to be used next.
6855 Dynamic adaptation plan may cross or cover multiple supported
6856 vectoring points in their natural processing order.
6858 Routing is not allowed by default.
6860 Older ecap_service format without optional named parameters is
6861 deprecated but supported for backward compatibility.
6865 ecap_service s1 reqmod_precache ecap://filters.R.us/leakDetector?on_error=block bypass=off
6866 ecap_service s2 respmod_precache ecap://filters.R.us/virusFilter config=/etc/vf.cfg bypass=on
6869 NAME: loadable_modules
6871 IFDEF: USE_LOADABLE_MODULES
6872 LOC: Config.loadable_module_names
6875 Instructs Squid to load the specified dynamic module(s) or activate
6876 preloaded module(s).
6878 loadable_modules @DEFAULT_PREFIX@/lib/MinimalAdapter.so
6882 MESSAGE ADAPTATION OPTIONS
6883 -----------------------------------------------------------------------------
6886 NAME: adaptation_service_set
6887 TYPE: adaptation_service_set_type
6888 IFDEF: USE_ADAPTATION
6893 Configures an ordered set of similar, redundant services. This is
6894 useful when hot standby or backup adaptation servers are available.
6896 adaptation_service_set set_name service_name1 service_name2 ...
6898 The named services are used in the set declaration order. The first
6899 applicable adaptation service from the set is used first. The next
6900 applicable service is tried if and only if the transaction with the
6901 previous service fails and the message waiting to be adapted is still
6904 When adaptation starts, broken services are ignored as if they were
6905 not a part of the set. A broken service is a down optional service.
6907 The services in a set must be attached to the same vectoring point
6908 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
6910 If all services in a set are optional then adaptation failures are
6911 bypassable. If all services in the set are essential, then a
6912 transaction failure with one service may still be retried using
6913 another service from the set, but when all services fail, the master
6914 transaction fails as well.
6916 A set may contain a mix of optional and essential services, but that
6917 is likely to lead to surprising results because broken services become
6918 ignored (see above), making previously bypassable failures fatal.
6919 Technically, it is the bypassability of the last failed service that
6922 See also: adaptation_access adaptation_service_chain
6925 adaptation_service_set svcBlocker urlFilterPrimary urlFilterBackup
6926 adaptation service_set svcLogger loggerLocal loggerRemote
6929 NAME: adaptation_service_chain
6930 TYPE: adaptation_service_chain_type
6931 IFDEF: USE_ADAPTATION
6936 Configures a list of complementary services that will be applied
6937 one-by-one, forming an adaptation chain or pipeline. This is useful
6938 when Squid must perform different adaptations on the same message.
6940 adaptation_service_chain chain_name service_name1 svc_name2 ...
6942 The named services are used in the chain declaration order. The first
6943 applicable adaptation service from the chain is used first. The next
6944 applicable service is applied to the successful adaptation results of
6945 the previous service in the chain.
6947 When adaptation starts, broken services are ignored as if they were
6948 not a part of the chain. A broken service is a down optional service.
6950 Request satisfaction terminates the adaptation chain because Squid
6951 does not currently allow declaration of RESPMOD services at the
6952 "reqmod_precache" vectoring point (see icap_service or ecap_service).
6954 The services in a chain must be attached to the same vectoring point
6955 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
6957 A chain may contain a mix of optional and essential services. If an
6958 essential adaptation fails (or the failure cannot be bypassed for
6959 other reasons), the master transaction fails. Otherwise, the failure
6960 is bypassed as if the failed adaptation service was not in the chain.
6962 See also: adaptation_access adaptation_service_set
6965 adaptation_service_chain svcRequest requestLogger urlFilter leakDetector
6968 NAME: adaptation_access
6969 TYPE: adaptation_access_type
6970 IFDEF: USE_ADAPTATION
6974 Sends an HTTP transaction to an ICAP or eCAP adaptation service.
6976 adaptation_access service_name allow|deny [!]aclname...
6977 adaptation_access set_name allow|deny [!]aclname...
6979 At each supported vectoring point, the adaptation_access
6980 statements are processed in the order they appear in this
6981 configuration file. Statements pointing to the following services
6982 are ignored (i.e., skipped without checking their ACL):
6984 - services serving different vectoring points
6985 - "broken-but-bypassable" services
6986 - "up" services configured to ignore such transactions
6987 (e.g., based on the ICAP Transfer-Ignore header).
6989 When a set_name is used, all services in the set are checked
6990 using the same rules, to find the first applicable one. See
6991 adaptation_service_set for details.
6993 If an access list is checked and there is a match, the
6994 processing stops: For an "allow" rule, the corresponding
6995 adaptation service is used for the transaction. For a "deny"
6996 rule, no adaptation service is activated.
6998 It is currently not possible to apply more than one adaptation
6999 service at the same vectoring point to the same HTTP transaction.
7001 See also: icap_service and ecap_service
7004 adaptation_access service_1 allow all
7007 NAME: adaptation_service_iteration_limit
7009 IFDEF: USE_ADAPTATION
7010 LOC: Adaptation::Config::service_iteration_limit
7013 Limits the number of iterations allowed when applying adaptation
7014 services to a message. If your longest adaptation set or chain
7015 may have more than 16 services, increase the limit beyond its
7016 default value of 16. If detecting infinite iteration loops sooner
7017 is critical, make the iteration limit match the actual number
7018 of services in your longest adaptation set or chain.
7020 Infinite adaptation loops are most likely with routing services.
7022 See also: icap_service routing=1
7025 NAME: adaptation_masterx_shared_names
7027 IFDEF: USE_ADAPTATION
7028 LOC: Adaptation::Config::masterx_shared_name
7031 For each master transaction (i.e., the HTTP request and response
7032 sequence, including all related ICAP and eCAP exchanges), Squid
7033 maintains a table of metadata. The table entries are (name, value)
7034 pairs shared among eCAP and ICAP exchanges. The table is destroyed
7035 with the master transaction.
7037 This option specifies the table entry names that Squid must accept
7038 from and forward to the adaptation transactions.
7040 An ICAP REQMOD or RESPMOD transaction may set an entry in the
7041 shared table by returning an ICAP header field with a name
7042 specified in adaptation_masterx_shared_names.
7044 An eCAP REQMOD or RESPMOD transaction may set an entry in the
7045 shared table by implementing the libecap::visitEachOption() API
7046 to provide an option with a name specified in
7047 adaptation_masterx_shared_names.
7049 Squid will store and forward the set entry to subsequent adaptation
7050 transactions within the same master transaction scope.
7052 Only one shared entry name is supported at this time.
7055 # share authentication information among ICAP services
7056 adaptation_masterx_shared_names X-Subscriber-ID
7059 NAME: adaptation_meta
7060 TYPE: adaptation_meta_type
7061 IFDEF: USE_ADAPTATION
7062 LOC: Adaptation::Config::metaHeaders
7065 This option allows Squid administrator to add custom ICAP request
7066 headers or eCAP options to Squid ICAP requests or eCAP transactions.
7067 Use it to pass custom authentication tokens and other
7068 transaction-state related meta information to an ICAP/eCAP service.
7070 The addition of a meta header is ACL-driven:
7071 adaptation_meta name value [!]aclname ...
7073 Processing for a given header name stops after the first ACL list match.
7074 Thus, it is impossible to add two headers with the same name. If no ACL
7075 lists match for a given header name, no such header is added. For
7078 # do not debug transactions except for those that need debugging
7079 adaptation_meta X-Debug 1 needs_debugging
7081 # log all transactions except for those that must remain secret
7082 adaptation_meta X-Log 1 !keep_secret
7084 # mark transactions from users in the "G 1" group
7085 adaptation_meta X-Authenticated-Groups "G 1" authed_as_G1
7087 The "value" parameter may be a regular squid.conf token or a "double
7088 quoted string". Within the quoted string, use backslash (\) to escape
7089 any character, which is currently only useful for escaping backslashes
7090 and double quotes. For example,
7091 "this string has one backslash (\\) and two \"quotes\""
7097 LOC: Adaptation::Icap::TheConfig.repeat
7098 DEFAULT_IF_NONE: deny all
7100 This ACL determines which retriable ICAP transactions are
7101 retried. Transactions that received a complete ICAP response
7102 and did not have to consume or produce HTTP bodies to receive
7103 that response are usually retriable.
7105 icap_retry allow|deny [!]aclname ...
7107 Squid automatically retries some ICAP I/O timeouts and errors
7108 due to persistent connection race conditions.
7110 See also: icap_retry_limit
7113 NAME: icap_retry_limit
7116 LOC: Adaptation::Icap::TheConfig.repeat_limit
7119 Limits the number of retries allowed. When set to zero (default),
7120 no retries are allowed.
7122 Communication errors due to persistent connection race
7123 conditions are unavoidable, automatically retried, and do not
7124 count against this limit.
7126 See also: icap_retry
7132 -----------------------------------------------------------------------------
7135 NAME: check_hostnames
7138 LOC: Config.onoff.check_hostnames
7140 For security and stability reasons Squid can check
7141 hostnames for Internet standard RFC compliance. If you want
7142 Squid to perform these checks turn this directive on.
7145 NAME: allow_underscore
7148 LOC: Config.onoff.allow_underscore
7150 Underscore characters is not strictly allowed in Internet hostnames
7151 but nevertheless used by many sites. Set this to off if you want
7152 Squid to be strict about the standard.
7153 This check is performed only when check_hostnames is set to on.
7156 NAME: cache_dns_program
7158 IFDEF: USE_DNSHELPER
7159 DEFAULT: @DEFAULT_DNSSERVER@
7160 LOC: Config.Program.dnsserver
7162 Specify the location of the executable for dnslookup process.
7166 TYPE: HelperChildConfig
7167 IFDEF: USE_DNSHELPER
7168 DEFAULT: 32 startup=1 idle=1
7169 LOC: Config.dnsChildren
7171 The maximum number of processes spawn to service DNS name lookups.
7172 If you limit it too few Squid will have to wait for them to process
7173 a backlog of requests, slowing it down. If you allow too many they
7174 will use RAM and other system resources noticably.
7175 The maximum this may be safely set to is 32.
7177 The startup= and idle= options allow some measure of skew in your
7182 Sets a minimum of how many processes are to be spawned when Squid
7183 starts or reconfigures. When set to zero the first request will
7184 cause spawning of the first child process to handle it.
7186 Starting too few will cause an initial slowdown in traffic as Squid
7187 attempts to simultaneously spawn enough processes to cope.
7191 Sets a minimum of how many processes Squid is to try and keep available
7192 at all times. When traffic begins to rise above what the existing
7193 processes can handle this many more will be spawned up to the maximum
7194 configured. A minimum setting of 1 is required.
7197 NAME: dns_retransmit_interval
7200 LOC: Config.Timeout.idns_retransmit
7201 IFDEF: !USE_DNSHELPER
7203 Initial retransmit interval for DNS queries. The interval is
7204 doubled each time all configured DNS servers have been tried.
7210 LOC: Config.Timeout.idns_query
7211 IFDEF: !USE_DNSHELPER
7213 DNS Query timeout. If no response is received to a DNS query
7214 within this time all DNS servers for the queried domain
7215 are assumed to be unavailable.
7218 NAME: dns_packet_max
7221 LOC: Config.dns.packet_max
7222 IFDEF: !USE_DNSHELPER
7224 Maximum number of bytes packet size to advertise via EDNS.
7225 Set to "none" to disable EDNS large packet support.
7227 For legacy reasons DNS UDP replies will default to 512 bytes which
7228 is too small for many responses. EDNS provides a means for Squid to
7229 negotiate receiving larger responses back immediately without having
7230 to failover with repeat requests. Responses larger than this limit
7231 will retain the old behaviour of failover to TCP DNS.
7233 Squid has no real fixed limit internally, but allowing packet sizes
7234 over 1500 bytes requires network jumbogram support and is usually not
7237 WARNING: The RFC also indicates that some older resolvers will reply
7238 with failure of the whole request if the extension is added. Some
7239 resolvers have already been identified which will reply with mangled
7240 EDNS response on occasion. Usually in response to many-KB jumbogram
7241 sizes being advertised by Squid.
7242 Squid will currently treat these both as an unable-to-resolve domain
7243 even if it would be resolvable without EDNS.
7250 LOC: Config.onoff.res_defnames
7252 Normally the RES_DEFNAMES resolver option is disabled
7253 (see res_init(3)). This prevents caches in a hierarchy
7254 from interpreting single-component hostnames locally. To allow
7255 Squid to handle single-component names, enable this option.
7258 NAME: dns_nameservers
7261 LOC: Config.dns_nameservers
7263 Use this if you want to specify a list of DNS name servers
7264 (IP addresses) to use instead of those given in your
7265 /etc/resolv.conf file.
7266 On Windows platforms, if no value is specified here or in
7267 the /etc/resolv.conf file, the list of DNS name servers are
7268 taken from the Windows registry, both static and dynamic DHCP
7269 configurations are supported.
7271 Example: dns_nameservers 10.0.0.1 192.172.0.4
7276 DEFAULT: @DEFAULT_HOSTS@
7277 LOC: Config.etcHostsPath
7279 Location of the host-local IP name-address associations
7280 database. Most Operating Systems have such a file on different
7282 - Un*X & Linux: /etc/hosts
7283 - Windows NT/2000: %SystemRoot%\system32\drivers\etc\hosts
7284 (%SystemRoot% value install default is c:\winnt)
7285 - Windows XP/2003: %SystemRoot%\system32\drivers\etc\hosts
7286 (%SystemRoot% value install default is c:\windows)
7287 - Windows 9x/Me: %windir%\hosts
7288 (%windir% value is usually c:\windows)
7289 - Cygwin: /etc/hosts
7291 The file contains newline-separated definitions, in the
7292 form ip_address_in_dotted_form name [name ...] names are
7293 whitespace-separated. Lines beginning with an hash (#)
7294 character are comments.
7296 The file is checked at startup and upon configuration.
7297 If set to 'none', it won't be checked.
7298 If append_domain is used, that domain will be added to
7299 domain-local (i.e. not containing any dot character) host
7305 LOC: Config.appendDomain
7308 Appends local domain name to hostnames without any dots in
7309 them. append_domain must begin with a period.
7311 Be warned there are now Internet names with no dots in
7312 them using only top-domain names, so setting this may
7313 cause some Internet sites to become unavailable.
7316 append_domain .yourdomain.com
7319 NAME: ignore_unknown_nameservers
7321 LOC: Config.onoff.ignore_unknown_nameservers
7323 IFDEF: !USE_DNSHELPER
7325 By default Squid checks that DNS responses are received
7326 from the same IP addresses they are sent to. If they
7327 don't match, Squid ignores the response and writes a warning
7328 message to cache.log. You can allow responses from unknown
7329 nameservers by setting this option to 'off'.
7335 LOC: Config.dns.v4_first
7336 IFDEF: !USE_DNSHELPER
7338 With the IPv6 Internet being as fast or faster than IPv4 Internet
7339 for most networks Squid prefers to contact websites over IPv6.
7341 This option reverses the order of preference to make Squid contact
7342 dual-stack websites over IPv4 first. Squid will still perform both
7343 IPv6 and IPv4 DNS lookups before connecting.
7346 This option will restrict the situations under which IPv6
7347 connectivity is used (and tested). Hiding network problems
7348 which would otherwise be detected and warned about.
7352 COMMENT: (number of entries)
7355 LOC: Config.ipcache.size
7362 LOC: Config.ipcache.low
7369 LOC: Config.ipcache.high
7371 The size, low-, and high-water marks for the IP cache.
7374 NAME: fqdncache_size
7375 COMMENT: (number of entries)
7378 LOC: Config.fqdncache.size
7380 Maximum number of FQDN cache entries.
7385 -----------------------------------------------------------------------------
7392 LOC: Config.onoff.mem_pools
7394 If set, Squid will keep pools of allocated (but unused) memory
7395 available for future use. If memory is a premium on your
7396 system and you believe your malloc library outperforms Squid
7397 routines, disable this.
7400 NAME: memory_pools_limit
7404 LOC: Config.MemPools.limit
7406 Used only with memory_pools on:
7407 memory_pools_limit 50 MB
7409 If set to a non-zero value, Squid will keep at most the specified
7410 limit of allocated (but unused) memory in memory pools. All free()
7411 requests that exceed this limit will be handled by your malloc
7412 library. Squid does not pre-allocate any memory, just safe-keeps
7413 objects that otherwise would be free()d. Thus, it is safe to set
7414 memory_pools_limit to a reasonably high value even if your
7415 configuration will use less memory.
7417 If set to none, Squid will keep all memory it can. That is, there
7418 will be no limit on the total amount of memory used for safe-keeping.
7420 To disable memory allocation optimization, do not set
7421 memory_pools_limit to 0 or none. Set memory_pools to "off" instead.
7423 An overhead for maintaining memory pools is not taken into account
7424 when the limit is checked. This overhead is close to four bytes per
7425 object kept. However, pools may actually _save_ memory because of
7426 reduced memory thrashing in your malloc library.
7430 COMMENT: on|off|transparent|truncate|delete
7433 LOC: opt_forwarded_for
7435 If set to "on", Squid will append your client's IP address
7436 in the HTTP requests it forwards. By default it looks like:
7438 X-Forwarded-For: 192.1.2.3
7440 If set to "off", it will appear as
7442 X-Forwarded-For: unknown
7444 If set to "transparent", Squid will not alter the
7445 X-Forwarded-For header in any way.
7447 If set to "delete", Squid will delete the entire
7448 X-Forwarded-For header.
7450 If set to "truncate", Squid will remove all existing
7451 X-Forwarded-For entries, and place the client IP as the sole entry.
7454 NAME: cachemgr_passwd
7455 TYPE: cachemgrpasswd
7457 LOC: Config.passwd_list
7459 Specify passwords for cachemgr operations.
7461 Usage: cachemgr_passwd password action action ...
7463 Some valid actions are (see cache manager menu for a full list):
7503 * Indicates actions which will not be performed without a
7504 valid password, others can be performed if not listed here.
7506 To disable an action, set the password to "disable".
7507 To allow performing an action without a password, set the
7510 Use the keyword "all" to set the same password for all actions.
7513 cachemgr_passwd secret shutdown
7514 cachemgr_passwd lesssssssecret info stats/objects
7515 cachemgr_passwd disable all
7522 LOC: Config.onoff.client_db
7524 If you want to disable collecting per-client statistics,
7525 turn off client_db here.
7528 NAME: refresh_all_ims
7532 LOC: Config.onoff.refresh_all_ims
7534 When you enable this option, squid will always check
7535 the origin server for an update when a client sends an
7536 If-Modified-Since request. Many browsers use IMS
7537 requests when the user requests a reload, and this
7538 ensures those clients receive the latest version.
7540 By default (off), squid may return a Not Modified response
7541 based on the age of the cached version.
7544 NAME: reload_into_ims
7545 IFDEF: USE_HTTP_VIOLATIONS
7549 LOC: Config.onoff.reload_into_ims
7551 When you enable this option, client no-cache or ``reload''
7552 requests will be changed to If-Modified-Since requests.
7553 Doing this VIOLATES the HTTP standard. Enabling this
7554 feature could make you liable for problems which it
7557 see also refresh_pattern for a more selective approach.
7560 NAME: connect_retries
7562 LOC: Config.connect_retries
7565 This sets the maximum number of connection attempts made for each
7566 TCP connection. The connect_retries attempts must all still
7567 complete within the connection timeout period.
7569 The default is not to re-try if the first connection attempt fails.
7570 The (not recommended) maximum is 10 tries.
7572 A warning message will be generated if it is set to a too-high
7573 value and the configured value will be over-ridden.
7575 Note: These re-tries are in addition to forward_max_tries
7576 which limit how many different addresses may be tried to find
7580 NAME: retry_on_error
7582 LOC: Config.retry.onerror
7585 If set to ON Squid will automatically retry requests when
7586 receiving an error response with status 403 (Forbidden),
7587 500 (Internal Error), 501 or 503 (Service not available).
7588 Status 502 and 504 (Gateway errors) are always retried.
7590 This is mainly useful if you are in a complex cache hierarchy to
7591 work around access control errors.
7593 NOTE: This retry will attempt to find another working destination.
7594 Which is different from the server which just failed.
7597 NAME: as_whois_server
7599 LOC: Config.as_whois_server
7600 DEFAULT: whois.ra.net
7602 WHOIS server to query for AS numbers. NOTE: AS numbers are
7603 queried only when Squid starts up, not for every request.
7608 LOC: Config.onoff.offline
7611 Enable this option and Squid will never try to validate cached
7615 NAME: uri_whitespace
7616 TYPE: uri_whitespace
7617 LOC: Config.uri_whitespace
7620 What to do with requests that have whitespace characters in the
7623 strip: The whitespace characters are stripped out of the URL.
7624 This is the behavior recommended by RFC2396.
7625 deny: The request is denied. The user receives an "Invalid
7627 allow: The request is allowed and the URI is not changed. The
7628 whitespace characters remain in the URI. Note the
7629 whitespace is passed to redirector processes if they
7631 encode: The request is allowed and the whitespace characters are
7632 encoded according to RFC1738. This could be considered
7633 a violation of the HTTP/1.1
7634 RFC because proxies are not allowed to rewrite URI's.
7635 chop: The request is allowed and the URI is chopped at the
7636 first whitespace. This might also be considered a
7642 LOC: Config.chroot_dir
7645 Specifies a directory where Squid should do a chroot() while
7646 initializing. This also causes Squid to fully drop root
7647 privileges after initializing. This means, for example, if you
7648 use a HTTP port less than 1024 and try to reconfigure, you may
7649 get an error saying that Squid can not open the port.
7652 NAME: balance_on_multiple_ip
7654 LOC: Config.onoff.balance_on_multiple_ip
7657 Modern IP resolvers in squid sort lookup results by preferred access.
7658 By default squid will use these IP in order and only rotates to
7659 the next listed when the most preffered fails.
7661 Some load balancing servers based on round robin DNS have been
7662 found not to preserve user session state across requests
7663 to different IP addresses.
7665 Enabling this directive Squid rotates IP's per request.
7668 NAME: pipeline_prefetch
7670 LOC: Config.onoff.pipeline_prefetch
7673 To boost the performance of pipelined requests to closer
7674 match that of a non-proxied environment Squid can try to fetch
7675 up to two requests in parallel from a pipeline.
7677 Defaults to off for bandwidth management and access logging
7680 WARNING: pipelining breaks NTLM and Negotiate/Kerberos authentication.
7683 NAME: high_response_time_warning
7686 LOC: Config.warnings.high_rptm
7689 If the one-minute median response time exceeds this value,
7690 Squid prints a WARNING with debug level 0 to get the
7691 administrators attention. The value is in milliseconds.
7694 NAME: high_page_fault_warning
7696 LOC: Config.warnings.high_pf
7699 If the one-minute average page fault rate exceeds this
7700 value, Squid prints a WARNING with debug level 0 to get
7701 the administrators attention. The value is in page faults
7705 NAME: high_memory_warning
7707 LOC: Config.warnings.high_memory
7710 If the memory usage (as determined by mallinfo) exceeds
7711 this amount, Squid prints a WARNING with debug level 0 to get
7712 the administrators attention.
7715 NAME: sleep_after_fork
7716 COMMENT: (microseconds)
7718 LOC: Config.sleep_after_fork
7721 When this is set to a non-zero value, the main Squid process
7722 sleeps the specified number of microseconds after a fork()
7723 system call. This sleep may help the situation where your
7724 system reports fork() failures due to lack of (virtual)
7725 memory. Note, however, if you have a lot of child
7726 processes, these sleep delays will add up and your
7727 Squid will not service requests for some amount of time
7728 until all the child processes have been started.
7729 On Windows value less then 1000 (1 milliseconds) are
7733 NAME: windows_ipaddrchangemonitor
7734 IFDEF: _SQUID_MSWIN_
7738 LOC: Config.onoff.WIN32_IpAddrChangeMonitor
7740 On Windows Squid by default will monitor IP address changes and will
7741 reconfigure itself after any detected event. This is very useful for
7742 proxies connected to internet with dial-up interfaces.
7743 In some cases (a Proxy server acting as VPN gateway is one) it could be
7744 desiderable to disable this behaviour setting this to 'off'.
7745 Note: after changing this, Squid service must be restarted.
7750 IFDEF: USE_SQUID_EUI
7752 LOC: Eui::TheConfig.euiLookup
7754 Whether to lookup the EUI or MAC address of a connected client.
7757 NAME: max_filedescriptors max_filedesc
7760 LOC: Config.max_filedescriptors
7762 The maximum number of filedescriptors supported.
7764 The default "0" means Squid inherits the current ulimit setting.
7766 Note: Changing this requires a restart of Squid. Also
7767 not all comm loops supports large values.
7775 Number of main Squid processes or "workers" to fork and maintain.
7776 0: "no daemon" mode, like running "squid -N ..."
7777 1: "no SMP" mode, start one main Squid process daemon (default)
7778 N: start N main Squid process daemons (i.e., SMP mode)
7780 In SMP mode, each worker does nearly all what a single Squid daemon
7781 does (e.g., listen on http_port and forward HTTP requests).
7784 NAME: cpu_affinity_map
7785 TYPE: CpuAffinityMap
7786 LOC: Config.cpuAffinityMap
7789 Usage: cpu_affinity_map process_numbers=P1,P2,... cores=C1,C2,...
7791 Sets 1:1 mapping between Squid processes and CPU cores. For example,
7793 cpu_affinity_map process_numbers=1,2,3,4 cores=1,3,5,7
7795 affects processes 1 through 4 only and places them on the first
7796 four even cores, starting with core #1.
7798 CPU cores are numbered starting from 1. Requires support for
7799 sched_getaffinity(2) and sched_setaffinity(2) system calls.
7801 Multiple cpu_affinity_map options are merged.
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