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 default Squid configuration file. You may wish
34 to look at the Squid home page (http://www.squid-cache.org/)
35 for the FAQ and other documentation.
37 The default Squid config file shows what the defaults for
38 various options happen to be. If you don't need to change the
39 default, you shouldn't uncomment the line. Doing so may cause
40 run-time problems. In some cases "none" refers to no default
41 setting at all, while in other cases it refers to a valid
42 option - the comments for that keyword indicate if this is the
48 Configuration options can be included using the "include" directive.
49 Include takes a list of files to include. Quoting and wildcards is
54 include /path/to/included/file/squid.acl.config
56 Includes can be nested up to a hard-coded depth of 16 levels.
57 This arbitrary restriction is to prevent recursive include references
58 from causing Squid entering an infinite loop whilst trying to load
62 Conditional configuration
64 If-statements can be used to make configuration directives
68 ... regular configuration directives ...
70 ... regular configuration directives ...]
73 The else part is optional. The keywords "if", "else", and "endif"
74 must be typed on their own lines, as if they were regular
75 configuration directives.
77 These individual conditions types are supported:
80 Always evaluates to true.
82 Always evaluates to false.
84 Equality comparison of two integer numbers.
89 The following SMP-related preprocessor macros can be used.
91 ${process_name} expands to the current Squid process "name"
92 (e.g., squid1, squid2, or cache1).
94 ${process_number} expands to the current Squid process
95 identifier, which is an integer number (e.g., 1, 2, 3) unique
96 across all Squid processes.
99 # Options Removed in 3.2
100 NAME: ignore_expect_100
103 Remove this line. The HTTP/1.1 feature is now fully supported by default.
109 Remove this line. Configure FTP page display using the CSS controls in errorpages.css instead.
112 NAME: url_rewrite_concurrency
115 Remove this line. Set the 'concurrency=' option of url_rewrite_children instead.
118 # Options Removed in 3.1
122 Remove this line. DNS is no longer tested on startup.
125 NAME: extension_methods
128 Remove this line. All valid methods for HTTP are accepted by default.
131 # 2.7 Options Removed/Replaced in 3.1
139 Remove this line. HTTP/1.1 is supported by default.
142 NAME: upgrade_http0.9
145 Remove this line. ICY/1.0 streaming protocol is supported by default.
148 NAME: zph_local zph_mode zph_option zph_parent zph_sibling
151 Alter these entries. Use the qos_flows directive instead.
154 # Options Removed in 3.0
158 Since squid-3.0 replace with request_header_access or reply_header_access
159 depending on whether you wish to match client requests or server replies.
162 NAME: httpd_accel_no_pmtu_disc
165 Since squid-3.0 use the 'disable-pmtu-discovery' flag on http_port instead.
169 OPTIONS FOR AUTHENTICATION
170 -----------------------------------------------------------------------------
178 This is used to define parameters for the various authentication
179 schemes supported by Squid.
181 format: auth_param scheme parameter [setting]
183 The order in which authentication schemes are presented to the client is
184 dependent on the order the scheme first appears in config file. IE
185 has a bug (it's not RFC 2617 compliant) in that it will use the basic
186 scheme if basic is the first entry presented, even if more secure
187 schemes are presented. For now use the order in the recommended
188 settings section below. If other browsers have difficulties (don't
189 recognize the schemes offered even if you are using basic) either
190 put basic first, or disable the other schemes (by commenting out their
193 Once an authentication scheme is fully configured, it can only be
194 shutdown by shutting squid down and restarting. Changes can be made on
195 the fly and activated with a reconfigure. I.E. You can change to a
196 different helper, but not unconfigure the helper completely.
198 Please note that while this directive defines how Squid processes
199 authentication it does not automatically activate authentication.
200 To use authentication you must in addition make use of ACLs based
201 on login name in http_access (proxy_auth, proxy_auth_regex or
202 external with %LOGIN used in the format tag). The browser will be
203 challenged for authentication on the first such acl encountered
204 in http_access processing and will also be re-challenged for new
205 login credentials if the request is being denied by a proxy_auth
208 WARNING: authentication can't be used in a transparently intercepting
209 proxy as the client then thinks it is talking to an origin server and
210 not the proxy. This is a limitation of bending the TCP/IP protocol to
211 transparently intercepting port 80, not a limitation in Squid.
212 Ports flagged 'transparent', 'intercept', or 'tproxy' have
213 authentication disabled.
215 === Parameters for the basic scheme follow. ===
218 Specify the command for the external authenticator. Such a program
219 reads a line containing "username password" and replies "OK" or
220 "ERR" in an endless loop. "ERR" responses may optionally be followed
221 by a error description available as %m in the returned error page.
222 If you use an authenticator, make sure you have 1 acl of type
225 By default, the basic authentication scheme is not used unless a
226 program is specified.
228 If you want to use the traditional NCSA proxy authentication, set
229 this line to something like
231 auth_param basic program @DEFAULT_PREFIX@/libexec/ncsa_auth @DEFAULT_PREFIX@/etc/passwd
234 HTTP uses iso-latin-1 as characterset, while some authentication
235 backends such as LDAP expects UTF-8. If this is set to on Squid will
236 translate the HTTP iso-latin-1 charset to UTF-8 before sending the
237 username & password to the helper.
239 "children" numberofchildren [startup=N] [idle=N] [concurrency=N]
240 The maximum number of authenticator processes to spawn. If you start too few
241 Squid will have to wait for them to process a backlog of credential
242 verifications, slowing it down. When password verifications are
243 done via a (slow) network you are likely to need lots of
244 authenticator processes.
246 The startup= and idle= options permit some skew in the exact amount
247 run. A minimum of startup=N will begin during startup and reconfigure.
248 Squid will start more in groups of up to idle=N in an attempt to meet
249 traffic needs and to keep idle=N free above those traffic needs up to
252 The concurrency= option sets the number of concurrent requests the
253 helper can process. The default of 0 is used for helpers who only
254 supports one request at a time. Setting this to a number greater than
255 0 changes the protocol used to include a channel number first on the
256 request/response line, allowing multiple requests to be sent to the
257 same helper in parallell without wating for the response.
258 Must not be set unless it's known the helper supports this.
260 auth_param basic children 20 startup=0 idle=1
263 Specifies the realm name which is to be reported to the
264 client for the basic proxy authentication scheme (part of
265 the text the user will see when prompted their username and
266 password). There is no default.
267 auth_param basic realm Squid proxy-caching web server
269 "credentialsttl" timetolive
270 Specifies how long squid assumes an externally validated
271 username:password pair is valid for - in other words how
272 often the helper program is called for that user. Set this
273 low to force revalidation with short lived passwords. Note
274 setting this high does not impact your susceptibility
275 to replay attacks unless you are using an one-time password
276 system (such as SecureID). If you are using such a system,
277 you will be vulnerable to replay attacks unless you also
278 use the max_user_ip ACL in an http_access rule.
280 "casesensitive" on|off
281 Specifies if usernames are case sensitive. Most user databases are
282 case insensitive allowing the same username to be spelled using both
283 lower and upper case letters, but some are case sensitive. This
284 makes a big difference for user_max_ip ACL processing and similar.
285 auth_param basic casesensitive off
287 === Parameters for the digest scheme follow ===
290 Specify the command for the external authenticator. Such
291 a program reads a line containing "username":"realm" and
292 replies with the appropriate H(A1) value hex encoded or
293 ERR if the user (or his H(A1) hash) does not exists.
294 See rfc 2616 for the definition of H(A1).
295 "ERR" responses may optionally be followed by a error description
296 available as %m in the returned error page.
298 By default, the digest authentication scheme is not used unless a
299 program is specified.
301 If you want to use a digest authenticator, set this line to
304 auth_param digest program @DEFAULT_PREFIX@/bin/digest_pw_auth @DEFAULT_PREFIX@/etc/digpass
307 HTTP uses iso-latin-1 as characterset, while some authentication
308 backends such as LDAP expects UTF-8. If this is set to on Squid will
309 translate the HTTP iso-latin-1 charset to UTF-8 before sending the
310 username & password to the helper.
312 "children" numberofchildren [startup=N] [idle=N] [concurrency=N]
313 The maximum number of authenticator processes to spawn (default 5).
314 If you start too few Squid will have to wait for them to
315 process a backlog of H(A1) calculations, slowing it down.
316 When the H(A1) calculations are done via a (slow) network
317 you are likely to need lots of authenticator processes.
319 The startup= and idle= options permit some skew in the exact amount
320 run. A minimum of startup=N will begin during startup and reconfigure.
321 Squid will start more in groups of up to idle=N in an attempt to meet
322 traffic needs and to keep idle=N free above those traffic needs up to
325 The concurrency= option sets the number of concurrent requests the
326 helper can process. The default of 0 is used for helpers who only
327 supports one request at a time. Setting this to a number greater than
328 0 changes the protocol used to include a channel number first on the
329 request/response line, allowing multiple requests to be sent to the
330 same helper in parallell without wating for the response.
331 Must not be set unless it's known the helper supports this.
333 auth_param digest children 20 startup=0 idle=1
336 Specifies the realm name which is to be reported to the
337 client for the digest proxy authentication scheme (part of
338 the text the user will see when prompted their username and
339 password). There is no default.
340 auth_param digest realm Squid proxy-caching web server
342 "nonce_garbage_interval" timeinterval
343 Specifies the interval that nonces that have been issued
344 to client_agent's are checked for validity.
346 "nonce_max_duration" timeinterval
347 Specifies the maximum length of time a given nonce will be
350 "nonce_max_count" number
351 Specifies the maximum number of times a given nonce can be
354 "nonce_strictness" on|off
355 Determines if squid requires strict increment-by-1 behavior
356 for nonce counts, or just incrementing (off - for use when
357 useragents generate nonce counts that occasionally miss 1
358 (ie, 1,2,4,6)). Default off.
360 "check_nonce_count" on|off
361 This directive if set to off can disable the nonce count check
362 completely to work around buggy digest qop implementations in
363 certain mainstream browser versions. Default on to check the
364 nonce count to protect from authentication replay attacks.
366 "post_workaround" on|off
367 This is a workaround to certain buggy browsers who sends
368 an incorrect request digest in POST requests when reusing
369 the same nonce as acquired earlier on a GET request.
371 === NTLM scheme options follow ===
374 Specify the command for the external NTLM authenticator.
375 Such a program reads exchanged NTLMSSP packets with
376 the browser via Squid until authentication is completed.
377 If you use an NTLM authenticator, make sure you have 1 acl
378 of type proxy_auth. By default, the NTLM authenticator_program
381 auth_param ntlm program @DEFAULT_PREFIX@/bin/ntlm_auth
383 "children" numberofchildren [startup=N] [idle=N]
384 The maximum number of authenticator processes to spawn (default 5).
385 If you start too few Squid will have to wait for them to
386 process a backlog of credential verifications, slowing it
387 down. When credential verifications are done via a (slow)
388 network you are likely to need lots of authenticator
391 The startup= and idle= options permit some skew in the exact amount
392 run. A minimum of startup=N will begin during startup and reconfigure.
393 Squid will start more in groups of up to idle=N in an attempt to meet
394 traffic needs and to keep idle=N free above those traffic needs up to
397 auth_param ntlm children 20 startup=0 idle=1
400 If you experience problems with PUT/POST requests when using the
401 Negotiate authentication scheme then you can try setting this to
402 off. This will cause Squid to forcibly close the connection on
403 the initial requests where the browser asks which schemes are
404 supported by the proxy.
406 auth_param ntlm keep_alive on
408 === Options for configuring the NEGOTIATE auth-scheme follow ===
411 Specify the command for the external Negotiate authenticator.
412 This protocol is used in Microsoft Active-Directory enabled setups with
413 the Microsoft Internet Explorer or Mozilla Firefox browsers.
414 Its main purpose is to exchange credentials with the Squid proxy
415 using the Kerberos mechanisms.
416 If you use a Negotiate authenticator, make sure you have at least
417 one acl of type proxy_auth active. By default, the negotiate
418 authenticator_program is not used.
419 The only supported program for this role is the ntlm_auth
420 program distributed as part of Samba, version 4 or later.
422 auth_param negotiate program @DEFAULT_PREFIX@/bin/ntlm_auth --helper-protocol=gss-spnego
424 "children" numberofchildren [startup=N] [idle=N]
425 The maximum number of authenticator processes to spawn (default 5).
426 If you start too few Squid will have to wait for them to
427 process a backlog of credential verifications, slowing it
428 down. When crendential verifications are done via a (slow)
429 network you are likely to need lots of authenticator
432 The startup= and idle= options permit some skew in the exact amount
433 run. A minimum of startup=N will begin during startup and reconfigure.
434 Squid will start more in groups of up to idle=N in an attempt to meet
435 traffic needs and to keep idle=N free above those traffic needs up to
438 auth_param negotiate children 20 startup=0 idle=1
441 If you experience problems with PUT/POST requests when using the
442 Negotiate authentication scheme then you can try setting this to
443 off. This will cause Squid to forcibly close the connection on
444 the initial requests where the browser asks which schemes are
445 supported by the proxy.
447 auth_param negotiate keep_alive on
452 #Recommended minimum configuration per scheme:
453 #auth_param negotiate program <uncomment and complete this line to activate>
454 #auth_param negotiate children 20 startup=0 idle=1
455 #auth_param negotiate keep_alive on
457 #auth_param ntlm program <uncomment and complete this line to activate>
458 #auth_param ntlm children 20 startup=0 idle=1
459 #auth_param ntlm keep_alive on
461 #auth_param digest program <uncomment and complete this line>
462 #auth_param digest children 20 startup=0 idle=1
463 #auth_param digest realm Squid proxy-caching web server
464 #auth_param digest nonce_garbage_interval 5 minutes
465 #auth_param digest nonce_max_duration 30 minutes
466 #auth_param digest nonce_max_count 50
468 #auth_param basic program <uncomment and complete this line>
469 #auth_param basic children 5 startup=5 idle=1
470 #auth_param basic realm Squid proxy-caching web server
471 #auth_param basic credentialsttl 2 hours
474 NAME: authenticate_cache_garbage_interval
477 LOC: Config.authenticateGCInterval
479 The time period between garbage collection across the username cache.
480 This is a tradeoff between memory utilization (long intervals - say
481 2 days) and CPU (short intervals - say 1 minute). Only change if you
485 NAME: authenticate_ttl
488 LOC: Config.authenticateTTL
490 The time a user & their credentials stay in the logged in
491 user cache since their last request. When the garbage
492 interval passes, all user credentials that have passed their
493 TTL are removed from memory.
496 NAME: authenticate_ip_ttl
498 LOC: Config.authenticateIpTTL
501 If you use proxy authentication and the 'max_user_ip' ACL,
502 this directive controls how long Squid remembers the IP
503 addresses associated with each user. Use a small value
504 (e.g., 60 seconds) if your users might change addresses
505 quickly, as is the case with dialups. You might be safe
506 using a larger value (e.g., 2 hours) in a corporate LAN
507 environment with relatively static address assignments.
512 -----------------------------------------------------------------------------
515 NAME: external_acl_type
516 TYPE: externalAclHelper
517 LOC: Config.externalAclHelperList
520 This option defines external acl classes using a helper program
521 to look up the status
523 external_acl_type name [options] FORMAT.. /path/to/helper [helper arguments..]
527 ttl=n TTL in seconds for cached results (defaults to 3600
530 TTL for cached negative lookups (default same
533 Maximum number of acl helper processes spawned to service
534 external acl lookups of this type. (default 20)
536 Minimum number of acl helper processes to spawn during
537 startup and reconfigure to service external acl lookups
538 of this type. (default 0)
540 Number of acl helper processes to keep ahead of traffic
541 loads. Squid will spawn this many at once whenever load
542 rises above the capabilities of existing processes.
543 Up to the value of children-max. (default 1)
544 concurrency=n concurrency level per process. Only used with helpers
545 capable of processing more than one query at a time.
546 cache=n limit the result cache size, default is unbounded.
547 grace=n Percentage remaining of TTL where a refresh of a
548 cached entry should be initiated without needing to
549 wait for a new reply. (default is for no grace period)
550 protocol=2.5 Compatibility mode for Squid-2.5 external acl helpers
551 ipv4 / ipv6 IP-mode used to communicate to this helper.
552 For compatability with older configurations and helpers
553 the default is currently 'ipv4'.
555 FORMAT specifications
557 %LOGIN Authenticated user login name
558 %EXT_USER Username from external acl
559 %IDENT Ident user name
561 %SRCPORT Client source port
564 %PROTO Requested protocol
566 %PATH Requested URL path
567 %METHOD Request method
568 %MYADDR Squid interface address
569 %MYPORT Squid http_port number
570 %PATH Requested URL-path (including query-string if any)
571 %USER_CERT SSL User certificate in PEM format
572 %USER_CERTCHAIN SSL User certificate chain in PEM format
573 %USER_CERT_xx SSL User certificate subject attribute xx
574 %USER_CA_xx SSL User certificate issuer attribute xx
576 %>{Header} HTTP request header "Header"
578 HTTP request header "Hdr" list member "member"
580 HTTP request header list member using ; as
581 list separator. ; can be any non-alphanumeric
584 %<{Header} HTTP reply header "Header"
586 HTTP reply header "Hdr" list member "member"
588 HTTP reply header list member using ; as
589 list separator. ; can be any non-alphanumeric
592 In addition to the above, any string specified in the referencing
593 acl will also be included in the helper request line, after the
594 specified formats (see the "acl external" directive)
596 The helper receives lines per the above format specification,
597 and returns lines starting with OK or ERR indicating the validity
598 of the request and optionally followed by additional keywords with
601 General result syntax:
603 OK/ERR keyword=value ...
607 user= The users name (login)
608 password= The users password (for login= cache_peer option)
609 message= Message describing the reason. Available as %o
611 tag= Apply a tag to a request (for both ERR and OK results)
612 Only sets a tag, does not alter existing tags.
613 log= String to be logged in access.log. Available as
614 %ea in logformat specifications
616 If protocol=3.0 (the default) then URL escaping is used to protect
617 each value in both requests and responses.
619 If using protocol=2.5 then all values need to be enclosed in quotes
620 if they may contain whitespace, or the whitespace escaped using \.
621 And quotes or \ characters within the keyword value must be \ escaped.
623 When using the concurrency= option the protocol is changed by
624 introducing a query channel tag infront of the request/response.
625 The query channel tag is a number between 0 and concurrency-1.
633 Defining an Access List
635 Every access list definition must begin with an aclname and acltype,
636 followed by either type-specific arguments or a quoted filename that
639 acl aclname acltype argument ...
640 acl aclname acltype "file" ...
642 When using "file", the file should contain one item per line.
644 By default, regular expressions are CASE-SENSITIVE. To make
645 them case-insensitive, use the -i option.
647 Some acl types require suspending the current request in order
648 to access some external data source.
649 Those which do are marked with the tag [slow], those which
650 don't are marked as [fast].
651 See http://wiki.squid-cache.org/SquidFaq/SquidAcl
652 for further information
654 ***** ACL TYPES AVAILABLE *****
656 acl aclname src ip-address/netmask ... # clients IP address [fast]
657 acl aclname src addr1-addr2/netmask ... # range of addresses [fast]
658 acl aclname dst ip-address/netmask ... # URL host's IP address [slow]
659 acl aclname myip ip-address/netmask ... # local socket IP address [fast]
661 acl aclname arp mac-address ... (xx:xx:xx:xx:xx:xx notation)
662 # The arp ACL requires the special configure option --enable-arp-acl.
663 # Furthermore, the ARP ACL code is not portable to all operating systems.
664 # It works on Linux, Solaris, Windows, FreeBSD, and some
665 # other *BSD variants.
668 # NOTE: Squid can only determine the MAC address for clients that are on
669 # the same subnet. If the client is on a different subnet,
670 # then Squid cannot find out its MAC address.
672 acl aclname srcdomain .foo.com ...
673 # reverse lookup, from client IP [slow]
674 acl aclname dstdomain .foo.com ...
675 # Destination server from URL [fast]
676 acl aclname srcdom_regex [-i] \.foo\.com ...
677 # regex matching client name [slow]
678 acl aclname dstdom_regex [-i] \.foo\.com ...
679 # regex matching server [fast]
681 # For dstdomain and dstdom_regex a reverse lookup is tried if a IP
682 # based URL is used and no match is found. The name "none" is used
683 # if the reverse lookup fails.
685 acl aclname src_as number ...
686 acl aclname dst_as number ...
688 # Except for access control, AS numbers can be used for
689 # routing of requests to specific caches. Here's an
690 # example for routing all requests for AS#1241 and only
691 # those to mycache.mydomain.net:
692 # acl asexample dst_as 1241
693 # cache_peer_access mycache.mydomain.net allow asexample
694 # cache_peer_access mycache_mydomain.net deny all
696 acl aclname peername myPeer ...
698 # match against a named cache_peer entry
699 # set unique name= on cache_peer lines for reliable use.
701 acl aclname time [day-abbrevs] [h1:m1-h2:m2]
711 # h1:m1 must be less than h2:m2
713 acl aclname url_regex [-i] ^http:// ...
714 # regex matching on whole URL [fast]
715 acl aclname urlpath_regex [-i] \.gif$ ...
716 # regex matching on URL path [fast]
718 acl aclname port 80 70 21 0-1024... # destination TCP port [fast]
720 acl aclname myport 3128 ... # local socket TCP port [fast]
721 acl aclname myportname 3128 ... # http(s)_port name [fast]
723 acl aclname proto HTTP FTP ... # request protocol [fast]
725 acl aclname method GET POST ... # HTTP request method [fast]
727 acl aclname http_status 200 301 500- 400-403 ...
728 # status code in reply [fast]
730 acl aclname browser [-i] regexp ...
731 # pattern match on User-Agent header (see also req_header below) [fast]
733 acl aclname referer_regex [-i] regexp ...
734 # pattern match on Referer header [fast]
735 # Referer is highly unreliable, so use with care
737 acl aclname ident username ...
738 acl aclname ident_regex [-i] pattern ...
739 # string match on ident output [slow]
740 # use REQUIRED to accept any non-null ident.
742 acl aclname proxy_auth [-i] username ...
743 acl aclname proxy_auth_regex [-i] pattern ...
744 # perform http authentication challenge to the client and match against
745 # supplied credentials [slow]
747 # takes a list of allowed usernames.
748 # use REQUIRED to accept any valid username.
750 # Will use proxy authentication in forward-proxy scenarios, and plain
751 # http authenticaiton in reverse-proxy scenarios
753 # NOTE: when a Proxy-Authentication header is sent but it is not
754 # needed during ACL checking the username is NOT logged
757 # NOTE: proxy_auth requires a EXTERNAL authentication program
758 # to check username/password combinations (see
759 # auth_param directive).
761 # NOTE: proxy_auth can't be used in a transparent/intercepting proxy
762 # as the browser needs to be configured for using a proxy in order
763 # to respond to proxy authentication.
765 acl aclname snmp_community string ...
766 # A community string to limit access to your SNMP Agent [fast]
769 # acl snmppublic snmp_community public
771 acl aclname maxconn number
772 # This will be matched when the client's IP address has
773 # more than <number> HTTP connections established. [fast]
775 acl aclname max_user_ip [-s] number
776 # This will be matched when the user attempts to log in from more
777 # than <number> different ip addresses. The authenticate_ip_ttl
778 # parameter controls the timeout on the ip entries. [fast]
779 # If -s is specified the limit is strict, denying browsing
780 # from any further IP addresses until the ttl has expired. Without
781 # -s Squid will just annoy the user by "randomly" denying requests.
782 # (the counter is reset each time the limit is reached and a
784 # NOTE: in acceleration mode or where there is mesh of child proxies,
785 # clients may appear to come from multiple addresses if they are
786 # going through proxy farms, so a limit of 1 may cause user problems.
788 acl aclname random probability
789 # Pseudo-randomly match requests. Based on the probability given.
790 # Probability may be written as a decimal (0.333), fraction (1/3)
791 # or ratio of matches:non-matches (3:5).
793 acl aclname req_mime_type [-i] mime-type ...
794 # regex match against the mime type of the request generated
795 # by the client. Can be used to detect file upload or some
796 # types HTTP tunneling requests [fast]
797 # NOTE: This does NOT match the reply. You cannot use this
798 # to match the returned file type.
800 acl aclname req_header header-name [-i] any\.regex\.here
801 # regex match against any of the known request headers. May be
802 # thought of as a superset of "browser", "referer" and "mime-type"
805 acl aclname rep_mime_type [-i] mime-type ...
806 # regex match against the mime type of the reply received by
807 # squid. Can be used to detect file download or some
808 # types HTTP tunneling requests. [fast]
809 # NOTE: This has no effect in http_access rules. It only has
810 # effect in rules that affect the reply data stream such as
813 acl aclname rep_header header-name [-i] any\.regex\.here
814 # regex match against any of the known reply headers. May be
815 # thought of as a superset of "browser", "referer" and "mime-type"
818 acl aclname external class_name [arguments...]
819 # external ACL lookup via a helper class defined by the
820 # external_acl_type directive [slow]
822 acl aclname user_cert attribute values...
823 # match against attributes in a user SSL certificate
824 # attribute is one of DN/C/O/CN/L/ST [fast]
826 acl aclname ca_cert attribute values...
827 # match against attributes a users issuing CA SSL certificate
828 # attribute is one of DN/C/O/CN/L/ST [fast]
830 acl aclname ext_user username ...
831 acl aclname ext_user_regex [-i] pattern ...
832 # string match on username returned by external acl helper [slow]
833 # use REQUIRED to accept any non-null user name.
835 acl aclname tag tagvalue ...
836 # string match on tag returned by external acl helper [slow]
838 acl aclname hier_code codename ...
839 # string match against squid hierarchy code(s); [fast]
840 # e.g., DIRECT, PARENT_HIT, NONE, etc.
842 # NOTE: This has no effect in http_access rules. It only has
843 # effect in rules that affect the reply data stream such as
847 acl macaddress arp 09:00:2b:23:45:67
848 acl myexample dst_as 1241
849 acl password proxy_auth REQUIRED
850 acl fileupload req_mime_type -i ^multipart/form-data$
851 acl javascript rep_mime_type -i ^application/x-javascript$
855 # Recommended minimum configuration:
857 acl manager proto cache_object
858 acl localhost src 127.0.0.1/32 ::1
859 acl to_localhost dst 127.0.0.0/8 0.0.0.0/32 ::1
861 # Example rule allowing access from your local networks.
862 # Adapt to list your (internal) IP networks from where browsing
864 acl localnet src 10.0.0.0/8 # RFC1918 possible internal network
865 acl localnet src 172.16.0.0/12 # RFC1918 possible internal network
866 acl localnet src 192.168.0.0/16 # RFC1918 possible internal network
867 acl localnet src fc00::/7 # RFC 4193 local private network range
868 acl localnet src fe80::/10 # RFC 4291 link-local (directly plugged) machines
870 acl SSL_ports port 443
871 acl Safe_ports port 80 # http
872 acl Safe_ports port 21 # ftp
873 acl Safe_ports port 443 # https
874 acl Safe_ports port 70 # gopher
875 acl Safe_ports port 210 # wais
876 acl Safe_ports port 1025-65535 # unregistered ports
877 acl Safe_ports port 280 # http-mgmt
878 acl Safe_ports port 488 # gss-http
879 acl Safe_ports port 591 # filemaker
880 acl Safe_ports port 777 # multiling http
881 acl CONNECT method CONNECT
885 NAME: follow_x_forwarded_for
887 IFDEF: FOLLOW_X_FORWARDED_FOR
888 LOC: Config.accessList.followXFF
889 DEFAULT_IF_NONE: deny all
891 Allowing or Denying the X-Forwarded-For header to be followed to
892 find the original source of a request.
894 Requests may pass through a chain of several other proxies
895 before reaching us. The X-Forwarded-For header will contain a
896 comma-separated list of the IP addresses in the chain, with the
897 rightmost address being the most recent.
899 If a request reaches us from a source that is allowed by this
900 configuration item, then we consult the X-Forwarded-For header
901 to see where that host received the request from. If the
902 X-Forwarded-For header contains multiple addresses, we continue
903 backtracking until we reach an address for which we are not allowed
904 to follow the X-Forwarded-For header, or until we reach the first
905 address in the list. For the purpose of ACL used in the
906 follow_x_forwarded_for directive the src ACL type always matches
907 the address we are testing and srcdomain matches its rDNS.
909 The end result of this process is an IP address that we will
910 refer to as the indirect client address. This address may
911 be treated as the client address for access control, ICAP, delay
912 pools and logging, depending on the acl_uses_indirect_client,
913 icap_uses_indirect_client, delay_pool_uses_indirect_client,
914 log_uses_indirect_client and tproxy_uses_indirect_client options.
916 This clause only supports fast acl types.
917 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
919 SECURITY CONSIDERATIONS:
921 Any host for which we follow the X-Forwarded-For header
922 can place incorrect information in the header, and Squid
923 will use the incorrect information as if it were the
924 source address of the request. This may enable remote
925 hosts to bypass any access control restrictions that are
926 based on the client's source addresses.
930 acl localhost src 127.0.0.1
931 acl my_other_proxy srcdomain .proxy.example.com
932 follow_x_forwarded_for allow localhost
933 follow_x_forwarded_for allow my_other_proxy
936 NAME: acl_uses_indirect_client
939 IFDEF: FOLLOW_X_FORWARDED_FOR
941 LOC: Config.onoff.acl_uses_indirect_client
943 Controls whether the indirect client address
944 (see follow_x_forwarded_for) is used instead of the
945 direct client address in acl matching.
948 NAME: delay_pool_uses_indirect_client
951 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_DELAY_POOLS
953 LOC: Config.onoff.delay_pool_uses_indirect_client
955 Controls whether the indirect client address
956 (see follow_x_forwarded_for) is used instead of the
957 direct client address in delay pools.
960 NAME: log_uses_indirect_client
963 IFDEF: FOLLOW_X_FORWARDED_FOR
965 LOC: Config.onoff.log_uses_indirect_client
967 Controls whether the indirect client address
968 (see follow_x_forwarded_for) is used instead of the
969 direct client address in the access log.
972 NAME: tproxy_uses_indirect_client
975 IFDEF: FOLLOW_X_FORWARDED_FOR&&LINUX_NETFILTER
977 LOC: Config.onoff.tproxy_uses_indirect_client
979 Controls whether the indirect client address
980 (see follow_x_forwarded_for) is used instead of the
981 direct client address when spoofing the outgoing client.
983 This has no effect on requests arriving in non-tproxy
986 SECURITY WARNING: Usage of this option is dangerous
987 and should not be used trivially. Correct configuration
988 of folow_x_forewarded_for with a limited set of trusted
989 sources is required to prevent abuse of your proxy.
994 LOC: Config.accessList.http
995 DEFAULT_IF_NONE: deny all
997 Allowing or Denying access based on defined access lists
999 Access to the HTTP port:
1000 http_access allow|deny [!]aclname ...
1002 NOTE on default values:
1004 If there are no "access" lines present, the default is to deny
1007 If none of the "access" lines cause a match, the default is the
1008 opposite of the last line in the list. If the last line was
1009 deny, the default is allow. Conversely, if the last line
1010 is allow, the default will be deny. For these reasons, it is a
1011 good idea to have an "deny all" entry at the end of your access
1012 lists to avoid potential confusion.
1014 This clause supports both fast and slow acl types.
1015 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1020 # Recommended minimum Access Permission configuration:
1022 # Only allow cachemgr access from localhost
1023 http_access allow manager localhost
1024 http_access deny manager
1026 # Deny requests to certain unsafe ports
1027 http_access deny !Safe_ports
1029 # Deny CONNECT to other than secure SSL ports
1030 http_access deny CONNECT !SSL_ports
1032 # We strongly recommend the following be uncommented to protect innocent
1033 # web applications running on the proxy server who think the only
1034 # one who can access services on "localhost" is a local user
1035 #http_access deny to_localhost
1038 # INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS
1041 # Example rule allowing access from your local networks.
1042 # Adapt localnet in the ACL section to list your (internal) IP networks
1043 # from where browsing should be allowed
1044 http_access allow localnet
1045 http_access allow localhost
1047 # And finally deny all other access to this proxy
1048 http_access deny all
1052 NAME: adapted_http_access http_access2
1054 LOC: Config.accessList.adapted_http
1057 Allowing or Denying access based on defined access lists
1059 Essentially identical to http_access, but runs after redirectors
1060 and ICAP/eCAP adaptation. Allowing access control based on their
1063 If not set then only http_access is used.
1066 NAME: http_reply_access
1068 LOC: Config.accessList.reply
1071 Allow replies to client requests. This is complementary to http_access.
1073 http_reply_access allow|deny [!] aclname ...
1075 NOTE: if there are no access lines present, the default is to allow
1078 If none of the access lines cause a match the opposite of the
1079 last line will apply. Thus it is good practice to end the rules
1080 with an "allow all" or "deny all" entry.
1082 This clause supports both fast and slow acl types.
1083 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1088 LOC: Config.accessList.icp
1089 DEFAULT_IF_NONE: deny all
1091 Allowing or Denying access to the ICP port based on defined
1094 icp_access allow|deny [!]aclname ...
1096 See http_access for details
1098 This clause only supports fast acl types.
1099 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1101 # Allow ICP queries from local networks only
1102 #icp_access allow localnet
1103 #icp_access deny all
1109 LOC: Config.accessList.htcp
1110 DEFAULT_IF_NONE: deny all
1112 Allowing or Denying access to the HTCP port based on defined
1115 htcp_access allow|deny [!]aclname ...
1117 See http_access for details
1119 NOTE: The default if no htcp_access lines are present is to
1120 deny all traffic. This default may cause problems with peers
1121 using the htcp option.
1123 This clause only supports fast acl types.
1124 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1126 # Allow HTCP queries from local networks only
1127 #htcp_access allow localnet
1128 #htcp_access deny all
1131 NAME: htcp_clr_access
1134 LOC: Config.accessList.htcp_clr
1135 DEFAULT_IF_NONE: deny all
1137 Allowing or Denying access to purge content using HTCP based
1138 on defined access lists
1140 htcp_clr_access allow|deny [!]aclname ...
1142 See http_access for details
1144 This clause only supports fast acl types.
1145 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1147 # Allow HTCP CLR requests from trusted peers
1148 acl htcp_clr_peer src 172.16.1.2
1149 htcp_clr_access allow htcp_clr_peer
1154 LOC: Config.accessList.miss
1157 Use to force your neighbors to use you as a sibling instead of
1158 a parent. For example:
1160 acl localclients src 172.16.0.0/16
1161 miss_access allow localclients
1162 miss_access deny !localclients
1164 This means only your local clients are allowed to fetch
1165 MISSES and all other clients can only fetch HITS.
1167 By default, allow all clients who passed the http_access rules
1168 to fetch MISSES from us.
1170 This clause only supports fast acl types.
1171 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1174 NAME: ident_lookup_access
1177 DEFAULT_IF_NONE: deny all
1178 LOC: Ident::TheConfig.identLookup
1180 A list of ACL elements which, if matched, cause an ident
1181 (RFC 931) lookup to be performed for this request. For
1182 example, you might choose to always perform ident lookups
1183 for your main multi-user Unix boxes, but not for your Macs
1184 and PCs. By default, ident lookups are not performed for
1187 To enable ident lookups for specific client addresses, you
1188 can follow this example:
1190 acl ident_aware_hosts src 198.168.1.0/24
1191 ident_lookup_access allow ident_aware_hosts
1192 ident_lookup_access deny all
1194 Only src type ACL checks are fully supported. A srcdomain
1195 ACL might work at times, but it will not always provide
1198 This clause only supports fast acl types.
1199 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1202 NAME: reply_body_max_size
1203 COMMENT: size [acl acl...]
1206 LOC: Config.ReplyBodySize
1208 This option specifies the maximum size of a reply body. It can be
1209 used to prevent users from downloading very large files, such as
1210 MP3's and movies. When the reply headers are received, the
1211 reply_body_max_size lines are processed, and the first line where
1212 all (if any) listed ACLs are true is used as the maximum body size
1215 This size is checked twice. First when we get the reply headers,
1216 we check the content-length value. If the content length value exists
1217 and is larger than the allowed size, the request is denied and the
1218 user receives an error message that says "the request or reply
1219 is too large." If there is no content-length, and the reply
1220 size exceeds this limit, the client's connection is just closed
1221 and they will receive a partial reply.
1223 WARNING: downstream caches probably can not detect a partial reply
1224 if there is no content-length header, so they will cache
1225 partial responses and give them out as hits. You should NOT
1226 use this option if you have downstream caches.
1228 WARNING: A maximum size smaller than the size of squid's error messages
1229 will cause an infinite loop and crash squid. Ensure that the smallest
1230 non-zero value you use is greater that the maximum header size plus
1231 the size of your largest error page.
1233 If you set this parameter none (the default), there will be
1236 Configuration Format is:
1237 reply_body_max_size SIZE UNITS [acl ...]
1239 reply_body_max_size 10 MB
1245 -----------------------------------------------------------------------------
1248 NAME: http_port ascii_port
1249 TYPE: http_port_list
1251 LOC: Config.Sockaddr.http
1253 Usage: port [mode] [options]
1254 hostname:port [mode] [options]
1255 1.2.3.4:port [mode] [options]
1257 The socket addresses where Squid will listen for HTTP client
1258 requests. You may specify multiple socket addresses.
1259 There are three forms: port alone, hostname with port, and
1260 IP address with port. If you specify a hostname or IP
1261 address, Squid binds the socket to that specific
1262 address. Most likely, you do not need to bind to a specific
1263 address, so you can use the port number alone.
1265 If you are running Squid in accelerator mode, you
1266 probably want to listen on port 80 also, or instead.
1268 The -a command line option may be used to specify additional
1269 port(s) where Squid listens for proxy request. Such ports will
1270 be plain proxy ports with no options.
1272 You may specify multiple socket addresses on multiple lines.
1276 intercept Support for IP-Layer interception of
1277 outgoing requests without browser settings.
1278 NP: disables authentication and IPv6 on the port.
1280 tproxy Support Linux TPROXY for spoofing outgoing
1281 connections using the client IP address.
1282 NP: disables authentication and maybe IPv6 on the port.
1284 accel Accelerator mode. Also needs at least one of
1285 vhost / vport / defaultsite.
1287 ssl-bump Intercept each CONNECT request matching ssl_bump ACL,
1288 establish secure connection with the client and with
1289 the server, decrypt HTTP messages as they pass through
1290 Squid, and treat them as unencrypted HTTP messages,
1291 becoming the man-in-the-middle.
1293 The ssl_bump option is required to fully enable
1294 the SslBump feature.
1296 Omitting the mode flag causes default forward proxy mode to be used.
1299 Accelerator Mode Options:
1301 allow-direct Allow direct forwarding in accelerator mode. Normally
1302 accelerated requests are denied direct forwarding as if
1303 never_direct was used.
1305 defaultsite=domainname
1306 What to use for the Host: header if it is not present
1307 in a request. Determines what site (not origin server)
1308 accelerators should consider the default.
1311 vhost Using the Host header for virtual domain support.
1312 Also uses the port as specified in Host: header.
1314 vport IP based virtual host support. Using the http_port number
1315 in passed on Host: headers.
1317 vport=NN Uses the specified port number rather than the
1320 protocol= Protocol to reconstruct accelerated requests with.
1321 Defaults to http://.
1323 ignore-cc Ignore request Cache-Control headers.
1325 Warning: This option violates HTTP specifications if
1326 used in non-accelerator setups.
1329 SSL Bump Mode Options:
1331 cert= Path to SSL certificate (PEM format).
1333 key= Path to SSL private key file (PEM format)
1334 if not specified, the certificate file is
1335 assumed to be a combined certificate and
1338 version= The version of SSL/TLS supported
1339 1 automatic (default)
1344 cipher= Colon separated list of supported ciphers.
1346 options= Various SSL engine options. The most important
1348 NO_SSLv2 Disallow the use of SSLv2
1349 NO_SSLv3 Disallow the use of SSLv3
1350 NO_TLSv1 Disallow the use of TLSv1
1351 SINGLE_DH_USE Always create a new key when using
1352 temporary/ephemeral DH key exchanges
1353 See src/ssl_support.c or OpenSSL SSL_CTX_set_options
1354 documentation for a complete list of options.
1356 clientca= File containing the list of CAs to use when
1357 requesting a client certificate.
1359 cafile= File containing additional CA certificates to
1360 use when verifying client certificates. If unset
1361 clientca will be used.
1363 capath= Directory containing additional CA certificates
1364 and CRL lists to use when verifying client certificates.
1366 crlfile= File of additional CRL lists to use when verifying
1367 the client certificate, in addition to CRLs stored in
1368 the capath. Implies VERIFY_CRL flag below.
1370 dhparams= File containing DH parameters for temporary/ephemeral
1373 sslflags= Various flags modifying the use of SSL:
1375 Don't request client certificates
1376 immediately, but wait until acl processing
1377 requires a certificate (not yet implemented).
1379 Don't use the default CA lists built in
1382 Don't allow for session reuse. Each connection
1383 will result in a new SSL session.
1385 Verify CRL lists when accepting client
1388 Verify CRL lists for all certificates in the
1389 client certificate chain.
1391 sslcontext= SSL session ID context identifier.
1393 generate-host-certificates[=<on|off>]
1394 Dynamically create SSL server certificates for the
1395 destination hosts of bumped CONNECT requests.When
1396 enabled, the cert and key options are used to sign
1397 generated certificates. Otherwise generated
1398 certificate will be selfsigned.
1399 If there is CA certificate life time of generated
1400 certificate equals lifetime of CA certificate. If
1401 generated certificate is selfsigned lifetime is three
1403 This option is enabled by default when SslBump is used.
1404 See the sslBump option above for more information.
1406 dynamic_cert_mem_cache_size=SIZE
1407 Approximate total RAM size spent on cached generated
1408 certificates. If set to zero, caching is disabled. The
1409 default value is 4MB. An average XXX-bit certificate
1410 consumes about XXX bytes of RAM.
1414 connection-auth[=on|off]
1415 use connection-auth=off to tell Squid to prevent
1416 forwarding Microsoft connection oriented authentication
1417 (NTLM, Negotiate and Kerberos)
1419 disable-pmtu-discovery=
1420 Control Path-MTU discovery usage:
1421 off lets OS decide on what to do (default).
1422 transparent disable PMTU discovery when transparent
1424 always disable always PMTU discovery.
1426 In many setups of transparently intercepting proxies
1427 Path-MTU discovery can not work on traffic towards the
1428 clients. This is the case when the intercepting device
1429 does not fully track connections and fails to forward
1430 ICMP must fragment messages to the cache server. If you
1431 have such setup and experience that certain clients
1432 sporadically hang or never complete requests set
1433 disable-pmtu-discovery option to 'transparent'.
1435 name= Specifies a internal name for the port. Defaults to
1436 the port specification (port or addr:port)
1438 tcpkeepalive[=idle,interval,timeout]
1439 Enable TCP keepalive probes of idle connections.
1440 In seconds; idle is the initial time before TCP starts
1441 probing the connection, interval how often to probe, and
1442 timeout the time before giving up.
1444 If you run Squid on a dual-homed machine with an internal
1445 and an external interface we recommend you to specify the
1446 internal address:port in http_port. This way Squid will only be
1447 visible on the internal address.
1451 # Squid normally listens to port 3128
1452 http_port @DEFAULT_HTTP_PORT@
1458 TYPE: https_port_list
1460 LOC: Config.Sockaddr.https
1462 Usage: [ip:]port cert=certificate.pem [key=key.pem] [options...]
1464 The socket address where Squid will listen for HTTPS client
1467 This is really only useful for situations where you are running
1468 squid in accelerator mode and you want to do the SSL work at the
1471 You may specify multiple socket addresses on multiple lines,
1472 each with their own SSL certificate and/or options.
1476 accel Accelerator mode. Also needs at least one of
1477 defaultsite or vhost.
1479 defaultsite= The name of the https site presented on
1480 this port. Implies accel.
1482 vhost Accelerator mode using Host header for virtual
1483 domain support. Requires a wildcard certificate
1484 or other certificate valid for more than one domain.
1487 protocol= Protocol to reconstruct accelerated requests with.
1490 cert= Path to SSL certificate (PEM format).
1492 key= Path to SSL private key file (PEM format)
1493 if not specified, the certificate file is
1494 assumed to be a combined certificate and
1497 version= The version of SSL/TLS supported
1498 1 automatic (default)
1503 cipher= Colon separated list of supported ciphers.
1505 options= Various SSL engine options. The most important
1507 NO_SSLv2 Disallow the use of SSLv2
1508 NO_SSLv3 Disallow the use of SSLv3
1509 NO_TLSv1 Disallow the use of TLSv1
1510 SINGLE_DH_USE Always create a new key when using
1511 temporary/ephemeral DH key exchanges
1512 See src/ssl_support.c or OpenSSL SSL_CTX_set_options
1513 documentation for a complete list of options.
1515 clientca= File containing the list of CAs to use when
1516 requesting a client certificate.
1518 cafile= File containing additional CA certificates to
1519 use when verifying client certificates. If unset
1520 clientca will be used.
1522 capath= Directory containing additional CA certificates
1523 and CRL lists to use when verifying client certificates.
1525 crlfile= File of additional CRL lists to use when verifying
1526 the client certificate, in addition to CRLs stored in
1527 the capath. Implies VERIFY_CRL flag below.
1529 dhparams= File containing DH parameters for temporary/ephemeral
1532 sslflags= Various flags modifying the use of SSL:
1534 Don't request client certificates
1535 immediately, but wait until acl processing
1536 requires a certificate (not yet implemented).
1538 Don't use the default CA lists built in
1541 Don't allow for session reuse. Each connection
1542 will result in a new SSL session.
1544 Verify CRL lists when accepting client
1547 Verify CRL lists for all certificates in the
1548 client certificate chain.
1550 sslcontext= SSL session ID context identifier.
1552 vport Accelerator with IP based virtual host support.
1554 vport=NN As above, but uses specified port number rather
1555 than the https_port number. Implies accel.
1557 name= Specifies a internal name for the port. Defaults to
1558 the port specification (port or addr:port)
1562 NAME: tcp_outgoing_tos tcp_outgoing_ds tcp_outgoing_dscp
1565 LOC: Ip::Qos::TheConfig.tosToServer
1567 Allows you to select a TOS/Diffserv value for packets outgoing
1568 on the server side, based on an ACL.
1570 tcp_outgoing_tos ds-field [!]aclname ...
1572 Example where normal_service_net uses the TOS value 0x00
1573 and good_service_net uses 0x20
1575 acl normal_service_net src 10.0.0.0/24
1576 acl good_service_net src 10.0.1.0/24
1577 tcp_outgoing_tos 0x00 normal_service_net
1578 tcp_outgoing_tos 0x20 good_service_net
1580 TOS/DSCP values really only have local significance - so you should
1581 know what you're specifying. For more information, see RFC2474,
1582 RFC2475, and RFC3260.
1584 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
1585 "default" to use whatever default your host has. Note that in
1586 practice often only multiples of 4 is usable as the two rightmost bits
1587 have been redefined for use by ECN (RFC 3168 section 23.1).
1589 Processing proceeds in the order specified, and stops at first fully
1593 NAME: clientside_tos
1596 LOC: Ip::Qos::TheConfig.tosToClient
1598 Allows you to select a TOS/Diffserv value for packets being transmitted
1599 on the client-side, based on an ACL.
1601 clientside_tos ds-field [!]aclname ...
1603 Example where normal_service_net uses the TOS value 0x00
1604 and good_service_net uses 0x20
1606 acl normal_service_net src 10.0.0.0/24
1607 acl good_service_net src 10.0.1.0/24
1608 clientside_tos 0x00 normal_service_net
1609 clientside_tos 0x20 good_service_net
1611 Note: This feature is incompatible with qos_flows. Any TOS values set here
1612 will be overwritten by TOS values in qos_flows.
1615 NAME: tcp_outgoing_mark
1619 LOC: Ip::Qos::TheConfig.nfmarkToServer
1621 Allows you to apply a Netfilter mark value to outgoing packets
1622 on the server side, based on an ACL.
1624 tcp_outgoing_mark mark-value [!]aclname ...
1626 Example where normal_service_net uses the mark value 0x00
1627 and good_service_net uses 0x20
1629 acl normal_service_net src 10.0.0.0/24
1630 acl good_service_net src 10.0.1.0/24
1631 tcp_outgoing_mark 0x00 normal_service_net
1632 tcp_outgoing_mark 0x20 good_service_net
1635 NAME: clientside_mark
1639 LOC: Ip::Qos::TheConfig.nfmarkToClient
1641 Allows you to apply a Netfilter mark value to packets being transmitted
1642 on the client-side, based on an ACL.
1644 clientside_mark mark-value [!]aclname ...
1646 Example where normal_service_net uses the mark value 0x00
1647 and good_service_net uses 0x20
1649 acl normal_service_net src 10.0.0.0/24
1650 acl good_service_net src 10.0.1.0/24
1651 clientside_mark 0x00 normal_service_net
1652 clientside_mark 0x20 good_service_net
1654 Note: This feature is incompatible with qos_flows. Any mark values set here
1655 will be overwritten by mark values in qos_flows.
1662 LOC: Ip::Qos::TheConfig
1664 Allows you to select a TOS/DSCP value to mark outgoing
1665 connections with, based on where the reply was sourced. For
1666 platforms using netfilter, allows you to set a netfilter mark
1667 value instead of, or in addition to, a TOS value.
1669 TOS values really only have local significance - so you should
1670 know what you're specifying. For more information, see RFC2474,
1671 RFC2475, and RFC3260.
1673 The TOS/DSCP byte must be exactly that - a octet value 0 - 255. Note that
1674 in practice often only multiples of 4 is usable as the two rightmost bits
1675 have been redefined for use by ECN (RFC 3168 section 23.1).
1677 Mark values can be any unsigned 32-bit integer value.
1679 This setting is configured by setting the following values:
1681 tos|mark Whether to set TOS or netfilter mark values
1683 local-hit=0xFF Value to mark local cache hits.
1685 sibling-hit=0xFF Value to mark hits from sibling peers.
1687 parent-hit=0xFF Value to mark hits from parent peers.
1689 miss=0xFF Value to mark cache misses. Takes precedence
1690 over the preserve-miss feature (see below).
1692 The TOS variant of the following features are only possible on Linux
1693 and require your kernel to be patched with the TOS preserving ZPH
1694 patch, available from http://zph.bratcheda.org
1695 No patch is needed to preserve the netfilter mark, which will work
1696 with all variants of netfilter.
1698 disable-preserve-miss
1699 This option disables the preservation of the TOS or netfilter
1700 mark. By default, the existing TOS or netfilter mark value of
1701 the response coming from the remote server will be retained
1702 and masked with miss-mark.
1703 NOTE: in the case of a netfilter mark, the mark must be set on
1704 the connection (using the CONNMARK target) not on the packet
1708 Allows you to mask certain bits in the TOS or mark value
1709 received from the remote server, before copying the value to
1710 the TOS sent towards clients.
1711 Default for tos: 0xFF (TOS from server is not changed).
1712 Default for mark: 0xFFFFFFFF (mark from server is not changed).
1714 All of these features require the --enable-zph-qos compilation flag
1715 (enabled by default). Netfilter marking also requires the
1716 libnetfilter_conntrack libraries (--with-netfilter-conntrack) and
1717 libcap 2.09+ (--with-libcap).
1721 NAME: tcp_outgoing_address
1724 LOC: Config.accessList.outgoing_address
1726 Allows you to map requests to different outgoing IP addresses
1727 based on the username or source address of the user making
1730 tcp_outgoing_address ipaddr [[!]aclname] ...
1732 Example where requests from 10.0.0.0/24 will be forwarded
1733 with source address 10.1.0.1, 10.0.2.0/24 forwarded with
1734 source address 10.1.0.2 and the rest will be forwarded with
1735 source address 10.1.0.3.
1737 acl normal_service_net src 10.0.0.0/24
1738 acl good_service_net src 10.0.2.0/24
1739 tcp_outgoing_address 10.1.0.1 normal_service_net
1740 tcp_outgoing_address 10.1.0.2 good_service_net
1741 tcp_outgoing_address 10.1.0.3
1743 Processing proceeds in the order specified, and stops at first fully
1746 Note: The use of this directive using client dependent ACLs is
1747 incompatible with the use of server side persistent connections. To
1748 ensure correct results it is best to set server_persistent_connections
1749 to off when using this directive in such configurations.
1751 Note: The use of this directive to set a local IP on outgoing TCP links
1752 is incompatible with using TPROXY to set client IP out outbound TCP links.
1753 When needing to contact peers use the no-tproxy cache_peer option to
1754 re-enable normal forwarding such as this.
1758 Squid is built with a capability of bridging the IPv4 and IPv6
1760 tcp_outgoing_address as exampled above breaks this bridging by forcing
1761 all outbound traffic through a certain IPv4 which may be on the wrong
1762 side of the IPv4/IPv6 boundary.
1764 To operate with tcp_outgoing_address and keep the bridging benefits
1765 an additional ACL needs to be used which ensures the IPv6-bound traffic
1766 is never forced or permitted out the IPv4 interface.
1768 acl to_ipv6 dst ipv6
1769 tcp_outgoing_address 2002::c001 good_service_net to_ipv6
1770 tcp_outgoing_address 10.1.0.2 good_service_net !to_ipv6
1772 tcp_outgoing_address 2002::beef normal_service_net to_ipv6
1773 tcp_outgoing_address 10.1.0.1 normal_service_net !to_ipv6
1775 tcp_outgoing_address 2002::1 to_ipv6
1776 tcp_outgoing_address 10.1.0.3 !to_ipv6
1779 'dst ipv6' bases its selection assuming DIRECT access.
1780 If peers are used the peername ACL are needed to select outgoing
1781 address which can link to the peer.
1783 'dst ipv6' is a slow ACL. It will only work here if 'dst' is used
1784 previously in the http_access rules to locate the destination IP.
1785 Some more magic may be needed for that:
1786 http_access allow to_ipv6 !all
1787 (meaning, allow if to IPv6 but not from anywhere ;)
1793 -----------------------------------------------------------------------------
1796 NAME: ssl_unclean_shutdown
1800 LOC: Config.SSL.unclean_shutdown
1802 Some browsers (especially MSIE) bugs out on SSL shutdown
1809 LOC: Config.SSL.ssl_engine
1812 The OpenSSL engine to use. You will need to set this if you
1813 would like to use hardware SSL acceleration for example.
1816 NAME: sslproxy_client_certificate
1819 LOC: Config.ssl_client.cert
1822 Client SSL Certificate to use when proxying https:// URLs
1825 NAME: sslproxy_client_key
1828 LOC: Config.ssl_client.key
1831 Client SSL Key to use when proxying https:// URLs
1834 NAME: sslproxy_version
1837 LOC: Config.ssl_client.version
1840 SSL version level to use when proxying https:// URLs
1843 NAME: sslproxy_options
1846 LOC: Config.ssl_client.options
1849 SSL engine options to use when proxying https:// URLs
1851 The most important being:
1853 NO_SSLv2 Disallow the use of SSLv2
1854 NO_SSLv3 Disallow the use of SSLv3
1855 NO_TLSv1 Disallow the use of TLSv1
1857 Always create a new key when using
1858 temporary/ephemeral DH key exchanges
1860 These options vary depending on your SSL engine.
1861 See the OpenSSL SSL_CTX_set_options documentation for a
1862 complete list of possible options.
1865 NAME: sslproxy_cipher
1868 LOC: Config.ssl_client.cipher
1871 SSL cipher list to use when proxying https:// URLs
1873 Colon separated list of supported ciphers.
1876 NAME: sslproxy_cafile
1879 LOC: Config.ssl_client.cafile
1882 file containing CA certificates to use when verifying server
1883 certificates while proxying https:// URLs
1886 NAME: sslproxy_capath
1889 LOC: Config.ssl_client.capath
1892 directory containing CA certificates to use when verifying
1893 server certificates while proxying https:// URLs
1899 LOC: Config.accessList.ssl_bump
1902 This ACL controls which CONNECT requests to an http_port
1903 marked with an sslBump flag are actually "bumped". Please
1904 see the sslBump flag of an http_port option for more details
1905 about decoding proxied SSL connections.
1907 By default, no requests are bumped.
1909 See also: http_port sslBump
1911 This clause only supports fast acl types.
1912 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1915 # Example: Bump all requests except those originating from localhost and
1916 # those going to webax.com or example.com sites.
1918 acl localhost src 127.0.0.1/32
1919 acl broken_sites dstdomain .webax.com
1920 acl broken_sites dstdomain .example.com
1921 ssl_bump deny localhost
1922 ssl_bump deny broken_sites
1926 NAME: sslproxy_flags
1929 LOC: Config.ssl_client.flags
1932 Various flags modifying the use of SSL while proxying https:// URLs:
1933 DONT_VERIFY_PEER Accept certificates that fail verification.
1934 For refined control, see sslproxy_cert_error.
1935 NO_DEFAULT_CA Don't use the default CA list built in
1940 NAME: sslproxy_cert_error
1943 LOC: Config.ssl_client.cert_error
1946 Use this ACL to bypass server certificate validation errors.
1948 For example, the following lines will bypass all validation errors
1949 when talking to servers located at 172.16.0.0/16. All other
1950 validation errors will result in ERR_SECURE_CONNECT_FAIL error.
1952 acl BrokenServersAtTrustedIP dst 172.16.0.0/16
1953 sslproxy_cert_error allow BrokenServersAtTrustedIP
1954 sslproxy_cert_error deny all
1956 This clause only supports fast acl types.
1957 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1958 Using slow acl types may result in server crashes
1960 Without this option, all server certificate validation errors
1961 terminate the transaction. Bypassing validation errors is dangerous
1962 because an error usually implies that the server cannot be trusted and
1963 the connection may be insecure.
1965 See also: sslproxy_flags and DONT_VERIFY_PEER.
1967 Default setting: sslproxy_cert_error deny all
1972 NAME: sslpassword_program
1975 LOC: Config.Program.ssl_password
1978 Specify a program used for entering SSL key passphrases
1979 when using encrypted SSL certificate keys. If not specified
1980 keys must either be unencrypted, or Squid started with the -N
1981 option to allow it to query interactively for the passphrase.
1983 The key file name is given as argument to the program allowing
1984 selection of the right password if you have multiple encrypted
1989 OPTIONS RELATING TO EXTERNAL SSL_CRTD
1990 -----------------------------------------------------------------------------
1993 NAME: sslcrtd_program
1996 DEFAULT: @DEFAULT_SSL_CRTD@ -s @DEFAULT_SSL_DB_DIR@ -M 4MB
1997 LOC: Ssl::TheConfig.ssl_crtd
1999 Specify the location and options of the executable for ssl_crtd process.
2000 @DEFAULT_SSL_CRTD@ program requires -s and -M parameters
2001 For more information use:
2002 @DEFAULT_SSL_CRTD@ -h
2005 NAME: sslcrtd_children
2006 TYPE: HelperChildConfig
2008 DEFAULT: 32 startup=5 idle=1
2009 LOC: Ssl::TheConfig.ssl_crtdChildren
2011 The maximum number of processes spawn to service ssl server.
2012 The maximum this may be safely set to is 32.
2014 The startup= and idle= options allow some measure of skew in your
2019 Sets the minimum number of processes to spawn when Squid
2020 starts or reconfigures. When set to zero the first request will
2021 cause spawning of the first child process to handle it.
2023 Starting too few children temporary slows Squid under load while it
2024 tries to spawn enough additional processes to cope with traffic.
2028 Sets a minimum of how many processes Squid is to try and keep available
2029 at all times. When traffic begins to rise above what the existing
2030 processes can handle this many more will be spawned up to the maximum
2031 configured. A minimum setting of 1 is required.
2033 You must have at least one ssl_crtd process.
2037 OPTIONS WHICH AFFECT THE NEIGHBOR SELECTION ALGORITHM
2038 -----------------------------------------------------------------------------
2046 To specify other caches in a hierarchy, use the format:
2048 cache_peer hostname type http-port icp-port [options]
2053 # hostname type port port options
2054 # -------------------- -------- ----- ----- -----------
2055 cache_peer parent.foo.net parent 3128 3130 default
2056 cache_peer sib1.foo.net sibling 3128 3130 proxy-only
2057 cache_peer sib2.foo.net sibling 3128 3130 proxy-only
2058 cache_peer example.com parent 80 0 no-query default
2059 cache_peer cdn.example.com sibling 3128 0
2061 type: either 'parent', 'sibling', or 'multicast'.
2063 proxy-port: The port number where the peer accept HTTP requests.
2064 For other Squid proxies this is usually 3128
2065 For web servers this is usually 80
2067 icp-port: Used for querying neighbor caches about objects.
2068 Set to 0 if the peer does not support ICP or HTCP.
2069 See ICP and HTCP options below for additional details.
2072 ==== ICP OPTIONS ====
2074 You MUST also set icp_port and icp_access explicitly when using these options.
2075 The defaults will prevent peer traffic using ICP.
2078 no-query Disable ICP queries to this neighbor.
2081 Indicates the named peer is a member of a multicast group.
2082 ICP queries will not be sent directly to the peer, but ICP
2083 replies will be accepted from it.
2085 closest-only Indicates that, for ICP_OP_MISS replies, we'll only forward
2086 CLOSEST_PARENT_MISSes and never FIRST_PARENT_MISSes.
2089 To only send ICP queries to this neighbor infrequently.
2090 This is used to keep the neighbor round trip time updated
2091 and is usually used in conjunction with weighted-round-robin.
2094 ==== HTCP OPTIONS ====
2096 You MUST also set htcp_port and htcp_access explicitly when using these options.
2097 The defaults will prevent peer traffic using HTCP.
2100 htcp Send HTCP, instead of ICP, queries to the neighbor.
2101 You probably also want to set the "icp-port" to 4827
2102 instead of 3130. This directive accepts a comma separated
2103 list of options described below.
2105 htcp=oldsquid Send HTCP to old Squid versions (2.5 or earlier).
2107 htcp=no-clr Send HTCP to the neighbor but without
2108 sending any CLR requests. This cannot be used with
2111 htcp=only-clr Send HTCP to the neighbor but ONLY CLR requests.
2112 This cannot be used with no-clr.
2115 Send HTCP to the neighbor including CLRs but only when
2116 they do not result from PURGE requests.
2119 Forward any HTCP CLR requests this proxy receives to the peer.
2122 ==== PEER SELECTION METHODS ====
2124 The default peer selection method is ICP, with the first responding peer
2125 being used as source. These options can be used for better load balancing.
2128 default This is a parent cache which can be used as a "last-resort"
2129 if a peer cannot be located by any of the peer-selection methods.
2130 If specified more than once, only the first is used.
2132 round-robin Load-Balance parents which should be used in a round-robin
2133 fashion in the absence of any ICP queries.
2134 weight=N can be used to add bias.
2136 weighted-round-robin
2137 Load-Balance parents which should be used in a round-robin
2138 fashion with the frequency of each parent being based on the
2139 round trip time. Closer parents are used more often.
2140 Usually used for background-ping parents.
2141 weight=N can be used to add bias.
2143 carp Load-Balance parents which should be used as a CARP array.
2144 The requests will be distributed among the parents based on the
2145 CARP load balancing hash function based on their weight.
2147 userhash Load-balance parents based on the client proxy_auth or ident username.
2149 sourcehash Load-balance parents based on the client source IP.
2152 To be used only for cache peers of type "multicast".
2153 ALL members of this multicast group have "sibling"
2154 relationship with it, not "parent". This is to a mulicast
2155 group when the requested object would be fetched only from
2156 a "parent" cache, anyway. It's useful, e.g., when
2157 configuring a pool of redundant Squid proxies, being
2158 members of the same multicast group.
2161 ==== PEER SELECTION OPTIONS ====
2163 weight=N use to affect the selection of a peer during any weighted
2164 peer-selection mechanisms.
2165 The weight must be an integer; default is 1,
2166 larger weights are favored more.
2167 This option does not affect parent selection if a peering
2168 protocol is not in use.
2170 basetime=N Specify a base amount to be subtracted from round trip
2172 It is subtracted before division by weight in calculating
2173 which parent to fectch from. If the rtt is less than the
2174 base time the rtt is set to a minimal value.
2176 ttl=N Specify a TTL to use when sending multicast ICP queries
2178 Only useful when sending to a multicast group.
2179 Because we don't accept ICP replies from random
2180 hosts, you must configure other group members as
2181 peers with the 'multicast-responder' option.
2183 no-delay To prevent access to this neighbor from influencing the
2186 digest-url=URL Tell Squid to fetch the cache digest (if digests are
2187 enabled) for this host from the specified URL rather
2188 than the Squid default location.
2191 ==== ACCELERATOR / REVERSE-PROXY OPTIONS ====
2193 originserver Causes this parent to be contacted as an origin server.
2194 Meant to be used in accelerator setups when the peer
2198 Set the Host header of requests forwarded to this peer.
2199 Useful in accelerator setups where the server (peer)
2200 expects a certain domain name but clients may request
2201 others. ie example.com or www.example.com
2203 no-digest Disable request of cache digests.
2206 Disables requesting ICMP RTT database (NetDB).
2209 ==== AUTHENTICATION OPTIONS ====
2212 If this is a personal/workgroup proxy and your parent
2213 requires proxy authentication.
2215 Note: The string can include URL escapes (i.e. %20 for
2216 spaces). This also means % must be written as %%.
2219 Send login details received from client to this peer.
2220 Both Proxy- and WWW-Authorization headers are passed
2221 without alteration to the peer.
2222 Authentication is not required by Squid for this to work.
2224 Note: This will pass any form of authentication but
2225 only Basic auth will work through a proxy unless the
2226 connection-auth options are also used.
2228 login=PASS Send login details received from client to this peer.
2229 Authentication is not required by this option.
2231 If there are no client-provided authentication headers
2232 to pass on, but username and password are available
2233 from an external ACL user= and password= result tags
2234 they may be sent instead.
2236 Note: To combine this with proxy_auth both proxies must
2237 share the same user database as HTTP only allows for
2238 a single login (one for proxy, one for origin server).
2239 Also be warned this will expose your users proxy
2240 password to the peer. USE WITH CAUTION
2243 Send the username to the upstream cache, but with a
2244 fixed password. This is meant to be used when the peer
2245 is in another administrative domain, but it is still
2246 needed to identify each user.
2247 The star can optionally be followed by some extra
2248 information which is added to the username. This can
2249 be used to identify this proxy to the peer, similar to
2250 the login=username:password option above.
2253 If this is a personal/workgroup proxy and your parent
2254 requires a secure proxy authentication.
2255 The first principal from the default keytab or defined by
2256 the environment variable KRB5_KTNAME will be used.
2258 login=NEGOTIATE:principal_name
2259 If this is a personal/workgroup proxy and your parent
2260 requires a secure proxy authentication.
2261 The principal principal_name from the default keytab or
2262 defined by the environment variable KRB5_KTNAME will be
2265 connection-auth=on|off
2266 Tell Squid that this peer does or not support Microsoft
2267 connection oriented authentication, and any such
2268 challenges received from there should be ignored.
2269 Default is auto to automatically determine the status
2273 ==== SSL / HTTPS / TLS OPTIONS ====
2275 ssl Encrypt connections to this peer with SSL/TLS.
2277 sslcert=/path/to/ssl/certificate
2278 A client SSL certificate to use when connecting to
2281 sslkey=/path/to/ssl/key
2282 The private SSL key corresponding to sslcert above.
2283 If 'sslkey' is not specified 'sslcert' is assumed to
2284 reference a combined file containing both the
2285 certificate and the key.
2288 The SSL version to use when connecting to this peer
2289 1 = automatic (default)
2294 sslcipher=... The list of valid SSL ciphers to use when connecting
2297 ssloptions=... Specify various SSL engine options:
2298 NO_SSLv2 Disallow the use of SSLv2
2299 NO_SSLv3 Disallow the use of SSLv3
2300 NO_TLSv1 Disallow the use of TLSv1
2301 See src/ssl_support.c or the OpenSSL documentation for
2302 a more complete list.
2304 sslcafile=... A file containing additional CA certificates to use
2305 when verifying the peer certificate.
2307 sslcapath=... A directory containing additional CA certificates to
2308 use when verifying the peer certificate.
2310 sslcrlfile=... A certificate revocation list file to use when
2311 verifying the peer certificate.
2313 sslflags=... Specify various flags modifying the SSL implementation:
2316 Accept certificates even if they fail to
2319 Don't use the default CA list built in
2322 Don't verify the peer certificate
2323 matches the server name
2325 ssldomain= The peer name as advertised in it's certificate.
2326 Used for verifying the correctness of the received peer
2327 certificate. If not specified the peer hostname will be
2331 Enable the "Front-End-Https: On" header needed when
2332 using Squid as a SSL frontend in front of Microsoft OWA.
2333 See MS KB document Q307347 for details on this header.
2334 If set to auto the header will only be added if the
2335 request is forwarded as a https:// URL.
2338 ==== GENERAL OPTIONS ====
2341 A peer-specific connect timeout.
2342 Also see the peer_connect_timeout directive.
2344 connect-fail-limit=N
2345 How many times connecting to a peer must fail before
2346 it is marked as down. Default is 10.
2348 allow-miss Disable Squid's use of only-if-cached when forwarding
2349 requests to siblings. This is primarily useful when
2350 icp_hit_stale is used by the sibling. To extensive use
2351 of this option may result in forwarding loops, and you
2352 should avoid having two-way peerings with this option.
2353 For example to deny peer usage on requests from peer
2354 by denying cache_peer_access if the source is a peer.
2356 max-conn=N Limit the amount of connections Squid may open to this
2359 name=xxx Unique name for the peer.
2360 Required if you have multiple peers on the same host
2361 but different ports.
2362 This name can be used in cache_peer_access and similar
2363 directives to dentify the peer.
2364 Can be used by outgoing access controls through the
2367 no-tproxy Do not use the client-spoof TPROXY support when forwarding
2368 requests to this peer. Use normal address selection instead.
2370 proxy-only objects fetched from the peer will not be stored locally.
2374 NAME: cache_peer_domain cache_host_domain
2379 Use to limit the domains for which a neighbor cache will be
2382 cache_peer_domain cache-host domain [domain ...]
2383 cache_peer_domain cache-host !domain
2385 For example, specifying
2387 cache_peer_domain parent.foo.net .edu
2389 has the effect such that UDP query packets are sent to
2390 'bigserver' only when the requested object exists on a
2391 server in the .edu domain. Prefixing the domainname
2392 with '!' means the cache will be queried for objects
2395 NOTE: * Any number of domains may be given for a cache-host,
2396 either on the same or separate lines.
2397 * When multiple domains are given for a particular
2398 cache-host, the first matched domain is applied.
2399 * Cache hosts with no domain restrictions are queried
2401 * There are no defaults.
2402 * There is also a 'cache_peer_access' tag in the ACL
2406 NAME: cache_peer_access
2411 Similar to 'cache_peer_domain' but provides more flexibility by
2414 cache_peer_access cache-host allow|deny [!]aclname ...
2416 The syntax is identical to 'http_access' and the other lists of
2417 ACL elements. See the comments for 'http_access' below, or
2418 the Squid FAQ (http://wiki.squid-cache.org/SquidFaq/SquidAcl).
2421 NAME: neighbor_type_domain
2422 TYPE: hostdomaintype
2426 usage: neighbor_type_domain neighbor parent|sibling domain domain ...
2428 Modifying the neighbor type for specific domains is now
2429 possible. You can treat some domains differently than the
2430 default neighbor type specified on the 'cache_peer' line.
2431 Normally it should only be necessary to list domains which
2432 should be treated differently because the default neighbor type
2433 applies for hostnames which do not match domains listed here.
2436 cache_peer cache.foo.org parent 3128 3130
2437 neighbor_type_domain cache.foo.org sibling .com .net
2438 neighbor_type_domain cache.foo.org sibling .au .de
2441 NAME: dead_peer_timeout
2445 LOC: Config.Timeout.deadPeer
2447 This controls how long Squid waits to declare a peer cache
2448 as "dead." If there are no ICP replies received in this
2449 amount of time, Squid will declare the peer dead and not
2450 expect to receive any further ICP replies. However, it
2451 continues to send ICP queries, and will mark the peer as
2452 alive upon receipt of the first subsequent ICP reply.
2454 This timeout also affects when Squid expects to receive ICP
2455 replies from peers. If more than 'dead_peer' seconds have
2456 passed since the last ICP reply was received, Squid will not
2457 expect to receive an ICP reply on the next query. Thus, if
2458 your time between requests is greater than this timeout, you
2459 will see a lot of requests sent DIRECT to origin servers
2460 instead of to your parents.
2463 NAME: forward_max_tries
2466 LOC: Config.forward_max_tries
2468 Controls how many different forward paths Squid will try
2469 before giving up. See also forward_timeout.
2472 NAME: hierarchy_stoplist
2475 LOC: Config.hierarchy_stoplist
2477 A list of words which, if found in a URL, cause the object to
2478 be handled directly by this cache. In other words, use this
2479 to not query neighbor caches for certain objects. You may
2480 list this option multiple times.
2481 Note: never_direct overrides this option.
2484 # We recommend you to use at least the following line.
2485 hierarchy_stoplist cgi-bin ?
2490 MEMORY CACHE OPTIONS
2491 -----------------------------------------------------------------------------
2498 LOC: Config.memMaxSize
2500 NOTE: THIS PARAMETER DOES NOT SPECIFY THE MAXIMUM PROCESS SIZE.
2501 IT ONLY PLACES A LIMIT ON HOW MUCH ADDITIONAL MEMORY SQUID WILL
2502 USE AS A MEMORY CACHE OF OBJECTS. SQUID USES MEMORY FOR OTHER
2503 THINGS AS WELL. SEE THE SQUID FAQ SECTION 8 FOR DETAILS.
2505 'cache_mem' specifies the ideal amount of memory to be used
2507 * In-Transit objects
2509 * Negative-Cached objects
2511 Data for these objects are stored in 4 KB blocks. This
2512 parameter specifies the ideal upper limit on the total size of
2513 4 KB blocks allocated. In-Transit objects take the highest
2516 In-transit objects have priority over the others. When
2517 additional space is needed for incoming data, negative-cached
2518 and hot objects will be released. In other words, the
2519 negative-cached and hot objects will fill up any unused space
2520 not needed for in-transit objects.
2522 If circumstances require, this limit will be exceeded.
2523 Specifically, if your incoming request rate requires more than
2524 'cache_mem' of memory to hold in-transit objects, Squid will
2525 exceed this limit to satisfy the new requests. When the load
2526 decreases, blocks will be freed until the high-water mark is
2527 reached. Thereafter, blocks will be used to store hot
2531 NAME: maximum_object_size_in_memory
2535 LOC: Config.Store.maxInMemObjSize
2537 Objects greater than this size will not be attempted to kept in
2538 the memory cache. This should be set high enough to keep objects
2539 accessed frequently in memory to improve performance whilst low
2540 enough to keep larger objects from hoarding cache_mem.
2543 NAME: memory_cache_mode
2548 Controls which objects to keep in the memory cache (cache_mem)
2550 always Keep most recently fetched objects in memory (default)
2552 disk Only disk cache hits are kept in memory, which means
2553 an object must first be cached on disk and then hit
2554 a second time before cached in memory.
2556 network Only objects fetched from network is kept in memory
2559 NAME: memory_replacement_policy
2561 LOC: Config.memPolicy
2564 The memory replacement policy parameter determines which
2565 objects are purged from memory when memory space is needed.
2567 See cache_replacement_policy for details.
2572 -----------------------------------------------------------------------------
2575 NAME: cache_replacement_policy
2577 LOC: Config.replPolicy
2580 The cache replacement policy parameter determines which
2581 objects are evicted (replaced) when disk space is needed.
2583 lru : Squid's original list based LRU policy
2584 heap GDSF : Greedy-Dual Size Frequency
2585 heap LFUDA: Least Frequently Used with Dynamic Aging
2586 heap LRU : LRU policy implemented using a heap
2588 Applies to any cache_dir lines listed below this.
2590 The LRU policies keeps recently referenced objects.
2592 The heap GDSF policy optimizes object hit rate by keeping smaller
2593 popular objects in cache so it has a better chance of getting a
2594 hit. It achieves a lower byte hit rate than LFUDA though since
2595 it evicts larger (possibly popular) objects.
2597 The heap LFUDA policy keeps popular objects in cache regardless of
2598 their size and thus optimizes byte hit rate at the expense of
2599 hit rate since one large, popular object will prevent many
2600 smaller, slightly less popular objects from being cached.
2602 Both policies utilize a dynamic aging mechanism that prevents
2603 cache pollution that can otherwise occur with frequency-based
2604 replacement policies.
2606 NOTE: if using the LFUDA replacement policy you should increase
2607 the value of maximum_object_size above its default of 4096 KB to
2608 to maximize the potential byte hit rate improvement of LFUDA.
2610 For more information about the GDSF and LFUDA cache replacement
2611 policies see http://www.hpl.hp.com/techreports/1999/HPL-1999-69.html
2612 and http://fog.hpl.external.hp.com/techreports/98/HPL-98-173.html.
2618 LOC: Config.cacheSwap
2622 cache_dir Type Directory-Name Fs-specific-data [options]
2624 You can specify multiple cache_dir lines to spread the
2625 cache among different disk partitions.
2627 Type specifies the kind of storage system to use. Only "ufs"
2628 is built by default. To enable any of the other storage systems
2629 see the --enable-storeio configure option.
2631 'Directory' is a top-level directory where cache swap
2632 files will be stored. If you want to use an entire disk
2633 for caching, this can be the mount-point directory.
2634 The directory must exist and be writable by the Squid
2635 process. Squid will NOT create this directory for you.
2637 In SMP configurations, cache_dir must not precede the workers option
2638 and should use configuration macros or conditionals to give each
2639 worker interested in disk caching a dedicated cache directory.
2643 "ufs" is the old well-known Squid storage format that has always
2646 cache_dir ufs Directory-Name Mbytes L1 L2 [options]
2648 'Mbytes' is the amount of disk space (MB) to use under this
2649 directory. The default is 100 MB. Change this to suit your
2650 configuration. Do NOT put the size of your disk drive here.
2651 Instead, if you want Squid to use the entire disk drive,
2652 subtract 20% and use that value.
2654 'L1' is the number of first-level subdirectories which
2655 will be created under the 'Directory'. The default is 16.
2657 'L2' is the number of second-level subdirectories which
2658 will be created under each first-level directory. The default
2661 The aufs store type:
2663 "aufs" uses the same storage format as "ufs", utilizing
2664 POSIX-threads to avoid blocking the main Squid process on
2665 disk-I/O. This was formerly known in Squid as async-io.
2667 cache_dir aufs Directory-Name Mbytes L1 L2 [options]
2669 see argument descriptions under ufs above
2671 The diskd store type:
2673 "diskd" uses the same storage format as "ufs", utilizing a
2674 separate process to avoid blocking the main Squid process on
2677 cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n]
2679 see argument descriptions under ufs above
2681 Q1 specifies the number of unacknowledged I/O requests when Squid
2682 stops opening new files. If this many messages are in the queues,
2683 Squid won't open new files. Default is 64
2685 Q2 specifies the number of unacknowledged messages when Squid
2686 starts blocking. If this many messages are in the queues,
2687 Squid blocks until it receives some replies. Default is 72
2689 When Q1 < Q2 (the default), the cache directory is optimized
2690 for lower response time at the expense of a decrease in hit
2691 ratio. If Q1 > Q2, the cache directory is optimized for
2692 higher hit ratio at the expense of an increase in response
2695 The coss store type:
2697 NP: COSS filesystem in Squid-3 has been deemed too unstable for
2698 production use and has thus been removed from this release.
2699 We hope that it can be made usable again soon.
2701 block-size=n defines the "block size" for COSS cache_dir's.
2702 Squid uses file numbers as block numbers. Since file numbers
2703 are limited to 24 bits, the block size determines the maximum
2704 size of the COSS partition. The default is 512 bytes, which
2705 leads to a maximum cache_dir size of 512<<24, or 8 GB. Note
2706 you should not change the coss block size after Squid
2707 has written some objects to the cache_dir.
2709 The coss file store has changed from 2.5. Now it uses a file
2710 called 'stripe' in the directory names in the config - and
2711 this will be created by squid -z.
2715 no-store, no new objects should be stored to this cache_dir
2717 min-size=n, refers to the min object size in bytes this cache_dir
2718 will accept. It's used to restrict a cache_dir to only store
2719 large objects (e.g. aufs) while other storedirs are optimized
2720 for smaller objects (e.g. COSS). Defaults to 0.
2722 max-size=n, refers to the max object size in bytes this cache_dir
2723 supports. It is used to select the cache_dir to store the object.
2724 Note: To make optimal use of the max-size limits you should order
2725 the cache_dir lines with the smallest max-size value first and the
2726 ones with no max-size specification last.
2728 Note for coss, max-size must be less than COSS_MEMBUF_SZ,
2729 which can be changed with the --with-coss-membuf-size=N configure
2733 # Uncomment and adjust the following to add a disk cache directory.
2734 #cache_dir ufs @DEFAULT_SWAP_DIR@ 100 16 256
2738 NAME: store_dir_select_algorithm
2740 LOC: Config.store_dir_select_algorithm
2743 Set this to 'round-robin' as an alternative.
2746 NAME: max_open_disk_fds
2748 LOC: Config.max_open_disk_fds
2751 To avoid having disk as the I/O bottleneck Squid can optionally
2752 bypass the on-disk cache if more than this amount of disk file
2753 descriptors are open.
2755 A value of 0 indicates no limit.
2758 NAME: minimum_object_size
2762 LOC: Config.Store.minObjectSize
2764 Objects smaller than this size will NOT be saved on disk. The
2765 value is specified in kilobytes, and the default is 0 KB, which
2766 means there is no minimum.
2769 NAME: maximum_object_size
2773 LOC: Config.Store.maxObjectSize
2775 Objects larger than this size will NOT be saved on disk. The
2776 value is specified in kilobytes, and the default is 4MB. If
2777 you wish to get a high BYTES hit ratio, you should probably
2778 increase this (one 32 MB object hit counts for 3200 10KB
2779 hits). If you wish to increase speed more than your want to
2780 save bandwidth you should leave this low.
2782 NOTE: if using the LFUDA replacement policy you should increase
2783 this value to maximize the byte hit rate improvement of LFUDA!
2784 See replacement_policy below for a discussion of this policy.
2787 NAME: cache_swap_low
2788 COMMENT: (percent, 0-100)
2791 LOC: Config.Swap.lowWaterMark
2794 NAME: cache_swap_high
2795 COMMENT: (percent, 0-100)
2798 LOC: Config.Swap.highWaterMark
2801 The low- and high-water marks for cache object replacement.
2802 Replacement begins when the swap (disk) usage is above the
2803 low-water mark and attempts to maintain utilization near the
2804 low-water mark. As swap utilization gets close to high-water
2805 mark object eviction becomes more aggressive. If utilization is
2806 close to the low-water mark less replacement is done each time.
2808 Defaults are 90% and 95%. If you have a large cache, 5% could be
2809 hundreds of MB. If this is the case you may wish to set these
2810 numbers closer together.
2815 -----------------------------------------------------------------------------
2820 LOC: Config.Log.logformats
2825 logformat <name> <format specification>
2827 Defines an access log format.
2829 The <format specification> is a string with embedded % format codes
2831 % format codes all follow the same basic structure where all but
2832 the formatcode is optional. Output strings are automatically escaped
2833 as required according to their context and the output format
2834 modifiers are usually not needed, but can be specified if an explicit
2835 output format is desired.
2837 % ["|[|'|#] [-] [[0]width] [{argument}] formatcode
2839 " output in quoted string format
2840 [ output in squid text log format as used by log_mime_hdrs
2841 # output in URL quoted format
2845 width field width. If starting with 0 the
2846 output is zero padded
2847 {arg} argument such as header name etc
2851 % a literal % character
2852 sn Unique sequence number per log line entry
2853 err_code The ID of an error response served by Squid or
2854 a similar internal error identifier.
2855 err_detail Additional err_code-dependent error information.
2857 Connection related format codes:
2859 >a Client source IP address
2861 >p Client source port
2862 <A Server IP address or peer name
2863 la Local IP address (http_port)
2864 lp Local port number (http_port)
2865 <lp Local port number of the last server or peer connection
2867 Time related format codes:
2869 ts Seconds since epoch
2870 tu subsecond time (milliseconds)
2871 tl Local time. Optional strftime format argument
2872 default %d/%b/%Y:%H:%M:%S %z
2873 tg GMT time. Optional strftime format argument
2874 default %d/%b/%Y:%H:%M:%S %z
2875 tr Response time (milliseconds)
2876 dt Total time spent making DNS lookups (milliseconds)
2878 HTTP cache related format codes:
2880 [http::]>h Original request header. Optional header name argument
2881 on the format header[:[separator]element]
2882 [http::]>ha The HTTP request headers after adaptation and redirection.
2883 Optional header name argument as for >h
2884 [http::]<h Reply header. Optional header name argument
2886 [http::]un User name
2887 [http::]ul User name from authentication
2888 [http::]ui User name from ident
2889 [http::]us User name from SSL
2890 [http::]ue User name from external acl helper
2891 [http::]>Hs HTTP status code sent to the client
2892 [http::]<Hs HTTP status code received from the next hop
2893 [http::]<bs Number of HTTP-equivalent message body bytes
2894 received from the next hop, excluding chunked
2895 transfer encoding and control messages.
2896 Generated FTP/Gopher listings are treated as
2898 [http::]Ss Squid request status (TCP_MISS etc)
2899 [http::]Sh Squid hierarchy status (DEFAULT_PARENT etc)
2900 [http::]mt MIME content type
2901 [http::]rm Request method (GET/POST etc)
2902 [http::]ru Request URL
2903 [http::]rp Request URL-Path excluding hostname
2904 [http::]rv Request protocol version
2905 [http::]et Tag returned by external acl
2906 [http::]ea Log string returned by external acl
2907 [http::]<st Sent reply size including HTTP headers
2908 [http::]>st Received request size including HTTP headers. In the
2909 case of chunked requests the chunked encoding metadata
2911 [http::]>sh Received HTTP request headers size
2912 [http::]<sh Sent HTTP reply headers size
2913 [http::]st Request+Reply size including HTTP headers
2914 [http::]<sH Reply high offset sent
2915 [http::]<sS Upstream object size
2916 [http::]<pt Peer response time in milliseconds. The timer starts
2917 when the last request byte is sent to the next hop
2918 and stops when the last response byte is received.
2919 [http::]<tt Total server-side time in milliseconds. The timer
2920 starts with the first connect request (or write I/O)
2921 sent to the first selected peer. The timer stops
2922 with the last I/O with the last peer.
2924 If ICAP is enabled, the following two codes become available (as
2925 well as ICAP log codes documented with the icap_log option):
2927 icap::tt Total ICAP processing time for the HTTP
2928 transaction. The timer ticks when ICAP
2929 ACLs are checked and when ICAP
2930 transaction is in progress.
2932 icap::<last_h The header of the last ICAP response
2933 related to the HTTP transaction. Like
2934 <h, accepts an optional header name
2935 argument. Will not change semantics
2936 when multiple ICAP transactions per HTTP
2937 transaction are supported.
2939 If adaptation is enabled the following two codes become available:
2941 adapt::sum_trs Summed adaptation transaction response
2942 times recorded as a comma-separated list in
2943 the order of transaction start time. Each time
2944 value is recorded as an integer number,
2945 representing response time of one or more
2946 adaptation (ICAP or eCAP) transaction in
2947 milliseconds. When a failed transaction is
2948 being retried or repeated, its time is not
2949 logged individually but added to the
2950 replacement (next) transaction. See also:
2953 adapt::all_trs All adaptation transaction response times.
2954 Same as adaptation_strs but response times of
2955 individual transactions are never added
2956 together. Instead, all transaction response
2957 times are recorded individually.
2959 You can prefix adapt::*_trs format codes with adaptation
2960 service name in curly braces to record response time(s) specific
2961 to that service. For example: %{my_service}adapt::sum_trs
2963 The default formats available (which do not need re-defining) are:
2965 logformat squid %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %un %Sh/%<A %mt
2966 logformat squidmime %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %un %Sh/%<A %mt [%>h] [%<h]
2967 logformat common %>a %ui %un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st %Ss:%Sh
2968 logformat combined %>a %ui %un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
2971 NAME: access_log cache_access_log
2973 LOC: Config.Log.accesslogs
2974 DEFAULT_IF_NONE: daemon:@DEFAULT_ACCESS_LOG@ squid
2976 These files log client request activities. Has a line every HTTP or
2977 ICP request. The format is:
2978 access_log <module>:<place> [<logformat name> [acl acl ...]]
2979 access_log none [acl acl ...]]
2981 Will log to the specified module:place using the specified format (which
2982 must be defined in a logformat directive) those entries which match
2983 ALL the acl's specified (which must be defined in acl clauses).
2984 If no acl is specified, all requests will be logged to this destination.
2986 ===== Modules Currently available =====
2988 none Do not log any requests matching these ACL.
2989 Do not specify Place or logformat name.
2991 stdio Write each log line to disk immediately at the completion of
2993 Place: the filename and path to be written.
2995 daemon Very similar to stdio. But instead of writing to disk the log
2996 line is passed to a daemon helper for asychronous handling instead.
2997 Place: varies depending on the daemon.
2999 log_file_daemon Place: the file name and path to be written.
3001 syslog To log each request via syslog facility.
3002 Place: The syslog facility and priority level for these entries.
3003 Place Format: facility.priority
3005 where facility could be any of:
3006 authpriv, daemon, local0 ... local7 or user.
3008 And priority could be any of:
3009 err, warning, notice, info, debug.
3011 udp To send each log line as text data to a UDP receiver.
3012 Place: The destination host name or IP and port.
3013 Place Format: \\host:port
3015 tcp To send each log line as text data to a TCP receiver.
3016 Place: The destination host name or IP and port.
3017 Place Format: \\host:port
3020 access_log daemon:@DEFAULT_ACCESS_LOG@ squid
3026 LOC: Config.Log.icaplogs
3029 ICAP log files record ICAP transaction summaries, one line per
3032 The icap_log option format is:
3033 icap_log <filepath> [<logformat name> [acl acl ...]]
3034 icap_log none [acl acl ...]]
3036 Please see access_log option documentation for details. The two
3037 kinds of logs share the overall configuration approach and many
3040 ICAP processing of a single HTTP message or transaction may
3041 require multiple ICAP transactions. In such cases, multiple
3042 ICAP transaction log lines will correspond to a single access
3045 ICAP log uses logformat codes that make sense for an ICAP
3046 transaction. Header-related codes are applied to the HTTP header
3047 embedded in an ICAP server response, with the following caveats:
3048 For REQMOD, there is no HTTP response header unless the ICAP
3049 server performed request satisfaction. For RESPMOD, the HTTP
3050 request header is the header sent to the ICAP server. For
3051 OPTIONS, there are no HTTP headers.
3053 The following format codes are also available for ICAP logs:
3055 icap::<A ICAP server IP address. Similar to <A.
3057 icap::<service_name ICAP service name from the icap_service
3058 option in Squid configuration file.
3060 icap::ru ICAP Request-URI. Similar to ru.
3062 icap::rm ICAP request method (REQMOD, RESPMOD, or
3063 OPTIONS). Similar to existing rm.
3065 icap::>st Bytes sent to the ICAP server (TCP payload
3066 only; i.e., what Squid writes to the socket).
3068 icap::<st Bytes received from the ICAP server (TCP
3069 payload only; i.e., what Squid reads from
3072 icap::<bs Number of message body bytes received from the
3073 ICAP server. ICAP message body, if any, usually
3074 includes encapsulated HTTP message headers and
3075 possibly encapsulated HTTP message body. The
3076 HTTP body part is dechunked before its size is
3079 icap::tr Transaction response time (in
3080 milliseconds). The timer starts when
3081 the ICAP transaction is created and
3082 stops when the transaction is completed.
3085 icap::tio Transaction I/O time (in milliseconds). The
3086 timer starts when the first ICAP request
3087 byte is scheduled for sending. The timers
3088 stops when the last byte of the ICAP response
3091 icap::to Transaction outcome: ICAP_ERR* for all
3092 transaction errors, ICAP_OPT for OPTION
3093 transactions, ICAP_ECHO for 204
3094 responses, ICAP_MOD for message
3095 modification, and ICAP_SAT for request
3096 satisfaction. Similar to Ss.
3098 icap::Hs ICAP response status code. Similar to Hs.
3100 icap::>h ICAP request header(s). Similar to >h.
3102 icap::<h ICAP response header(s). Similar to <h.
3104 The default ICAP log format, which can be used without an explicit
3105 definition, is called icap_squid:
3107 logformat icap_squid %ts.%03tu %6icap::tr %>a %icap::to/%03icap::Hs %icap::<size %icap::rm %icap::ru% %un -/%icap::<A -
3109 See also: logformat, log_icap, and %icap::<last_h
3112 NAME: logfile_daemon
3114 DEFAULT: @DEFAULT_LOGFILED@
3115 LOC: Log::TheConfig.logfile_daemon
3117 Specify the path to the logfile-writing daemon. This daemon is
3118 used to write the access and store logs, if configured.
3120 Squid sends a number of commands to the log daemon:
3121 L<data>\n - logfile data
3126 r<n>\n - set rotate count to <n>
3127 b<n>\n - 1 = buffer output, 0 = don't buffer output
3129 No responses is expected.
3134 LOC: Config.accessList.log
3136 COMMENT: allow|deny acl acl...
3138 This options allows you to control which requests gets logged
3139 to access.log (see access_log directive). Requests denied for
3140 logging will also not be accounted for in performance counters.
3142 This clause only supports fast acl types.
3143 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
3149 LOC: Config.accessList.icap
3152 This options allows you to control which requests get logged
3153 to icap.log. See the icap_log directive for ICAP log details.
3156 NAME: cache_store_log
3159 LOC: Config.Log.store
3161 Logs the activities of the storage manager. Shows which
3162 objects are ejected from the cache, and which objects are
3163 saved and for how long. To disable, enter "none" or remove the line.
3164 There are not really utilities to analyze this data, so you can safely
3168 cache_store_log @DEFAULT_STORE_LOG@
3171 NAME: cache_swap_state cache_swap_log
3173 LOC: Config.Log.swap
3176 Location for the cache "swap.state" file. This index file holds
3177 the metadata of objects saved on disk. It is used to rebuild
3178 the cache during startup. Normally this file resides in each
3179 'cache_dir' directory, but you may specify an alternate
3180 pathname here. Note you must give a full filename, not just
3181 a directory. Since this is the index for the whole object
3182 list you CANNOT periodically rotate it!
3184 If %s can be used in the file name it will be replaced with a
3185 a representation of the cache_dir name where each / is replaced
3186 with '.'. This is needed to allow adding/removing cache_dir
3187 lines when cache_swap_log is being used.
3189 If have more than one 'cache_dir', and %s is not used in the name
3190 these swap logs will have names such as:
3196 The numbered extension (which is added automatically)
3197 corresponds to the order of the 'cache_dir' lines in this
3198 configuration file. If you change the order of the 'cache_dir'
3199 lines in this file, these index files will NOT correspond to
3200 the correct 'cache_dir' entry (unless you manually rename
3201 them). We recommend you do NOT use this option. It is
3202 better to keep these index files in each 'cache_dir' directory.
3205 NAME: logfile_rotate
3208 LOC: Config.Log.rotateNumber
3210 Specifies the number of logfile rotations to make when you
3211 type 'squid -k rotate'. The default is 10, which will rotate
3212 with extensions 0 through 9. Setting logfile_rotate to 0 will
3213 disable the file name rotation, but the logfiles are still closed
3214 and re-opened. This will enable you to rename the logfiles
3215 yourself just before sending the rotate signal.
3217 Note, the 'squid -k rotate' command normally sends a USR1
3218 signal to the running squid process. In certain situations
3219 (e.g. on Linux with Async I/O), USR1 is used for other
3220 purposes, so -k rotate uses another signal. It is best to get
3221 in the habit of using 'squid -k rotate' instead of 'kill -USR1
3224 Note, from Squid-3.1 this option has no effect on the cache.log,
3225 that log can be rotated separately by using debug_options
3228 NAME: emulate_httpd_log
3232 LOC: Config.onoff.common_log
3234 The Cache can emulate the log file format which many 'httpd'
3235 programs use. To disable/enable this emulation, set
3236 emulate_httpd_log to 'off' or 'on'. The default
3237 is to use the native log format since it includes useful
3238 information Squid-specific log analyzers use.
3241 NAME: log_ip_on_direct
3245 LOC: Config.onoff.log_ip_on_direct
3247 Log the destination IP address in the hierarchy log tag when going
3248 direct. Earlier Squid versions logged the hostname here. If you
3249 prefer the old way set this to off.
3254 DEFAULT: @DEFAULT_MIME_TABLE@
3255 LOC: Config.mimeTablePathname
3257 Pathname to Squid's MIME table. You shouldn't need to change
3258 this, but the default file contains examples and formatting
3259 information if you do.
3265 LOC: Config.onoff.log_mime_hdrs
3268 The Cache can record both the request and the response MIME
3269 headers for each HTTP transaction. The headers are encoded
3270 safely and will appear as two bracketed fields at the end of
3271 the access log (for either the native or httpd-emulated log
3272 formats). To enable this logging set log_mime_hdrs to 'on'.
3277 LOC: Config.Log.useragent
3279 IFDEF: USE_USERAGENT_LOG
3281 Squid will write the User-Agent field from HTTP requests
3282 to the filename specified here. By default useragent_log
3286 NAME: referer_log referrer_log
3288 LOC: Config.Log.referer
3290 IFDEF: USE_REFERER_LOG
3292 Squid will write the Referer field from HTTP requests to the
3293 filename specified here. By default referer_log is disabled.
3294 Note that "referer" is actually a misspelling of "referrer"
3295 however the misspelt version has been accepted into the HTTP RFCs
3301 DEFAULT: @DEFAULT_PID_FILE@
3302 LOC: Config.pidFilename
3304 A filename to write the process-id to. To disable, enter "none".
3310 Remove this option from your config. To log FQDN use %>A in the log format.
3313 NAME: client_netmask
3315 LOC: Config.Addrs.client_netmask
3318 A netmask for client addresses in logfiles and cachemgr output.
3319 Change this to protect the privacy of your cache clients.
3320 A netmask of 255.255.255.0 will log all IP's in that range with
3321 the last digit set to '0'.
3328 LOC: Config.Log.forward
3330 Logs the server-side requests.
3332 This is currently work in progress.
3335 NAME: strip_query_terms
3337 LOC: Config.onoff.strip_query_terms
3340 By default, Squid strips query terms from requested URLs before
3341 logging. This protects your user's privacy.
3348 LOC: Config.onoff.buffered_logs
3350 cache.log log file is written with stdio functions, and as such
3351 it can be buffered or unbuffered. By default it will be unbuffered.
3352 Buffering it can speed up the writing slightly (though you are
3353 unlikely to need to worry unless you run with tons of debugging
3354 enabled in which case performance will suffer badly anyway..).
3357 NAME: netdb_filename
3359 DEFAULT: @DEFAULT_NETDB_FILE@
3360 LOC: Config.netdbFilename
3363 A filename where Squid stores it's netdb state between restarts.
3364 To disable, enter "none".
3368 OPTIONS FOR TROUBLESHOOTING
3369 -----------------------------------------------------------------------------
3374 DEFAULT_IF_NONE: @DEFAULT_CACHE_LOG@
3375 LOC: Debug::cache_log
3377 Cache logging file. This is where general information about
3378 your cache's behavior goes. You can increase the amount of data
3379 logged to this file and how often its rotated with "debug_options"
3385 LOC: Debug::debugOptions
3387 Logging options are set as section,level where each source file
3388 is assigned a unique section. Lower levels result in less
3389 output, Full debugging (level 9) can result in a very large
3390 log file, so be careful.
3392 The magic word "ALL" sets debugging levels for all sections.
3393 We recommend normally running with "ALL,1".
3395 The rotate=N option can be used to keep more or less of these logs
3396 than would otherwise be kept by logfile_rotate.
3397 For most uses a single log should be enough to monitor current
3398 events affecting Squid.
3403 LOC: Config.coredump_dir
3404 DEFAULT_IF_NONE: none
3406 By default Squid leaves core files in the directory from where
3407 it was started. If you set 'coredump_dir' to a directory
3408 that exists, Squid will chdir() to that directory at startup
3409 and coredump files will be left there.
3413 # Leave coredumps in the first cache dir
3414 coredump_dir @DEFAULT_SWAP_DIR@
3420 OPTIONS FOR FTP GATEWAYING
3421 -----------------------------------------------------------------------------
3427 LOC: Config.Ftp.anon_user
3429 If you want the anonymous login password to be more informative
3430 (and enable the use of picky ftp servers), set this to something
3431 reasonable for your domain, like wwwuser@somewhere.net
3433 The reason why this is domainless by default is the
3434 request can be made on the behalf of a user in any domain,
3435 depending on how the cache is used.
3436 Some ftp server also validate the email address is valid
3437 (for example perl.com).
3443 LOC: Config.Ftp.passive
3445 If your firewall does not allow Squid to use passive
3446 connections, turn off this option.
3448 Use of ftp_epsv_all option requires this to be ON.
3454 LOC: Config.Ftp.epsv_all
3456 FTP Protocol extensions permit the use of a special "EPSV ALL" command.
3458 NATs may be able to put the connection on a "fast path" through the
3459 translator, as the EPRT command will never be used and therefore,
3460 translation of the data portion of the segments will never be needed.
3462 When a client only expects to do two-way FTP transfers this may be
3464 If squid finds that it must do a three-way FTP transfer after issuing
3465 an EPSV ALL command, the FTP session will fail.
3467 If you have any doubts about this option do not use it.
3468 Squid will nicely attempt all other connection methods.
3470 Requires ftp_passive to be ON (default) for any effect.
3476 LOC: Config.Ftp.epsv
3478 FTP Protocol extensions permit the use of a special "EPSV" command.
3480 NATs may be able to put the connection on a "fast path" through the
3481 translator using EPSV, as the EPRT command will never be used
3482 and therefore, translation of the data portion of the segments
3483 will never be needed.
3485 Turning this OFF will prevent EPSV being attempted.
3486 WARNING: Doing so will convert Squid back to the old behavior with all
3487 the related problems with external NAT devices/layers.
3489 Requires ftp_passive to be ON (default) for any effect.
3492 NAME: ftp_sanitycheck
3495 LOC: Config.Ftp.sanitycheck
3497 For security and data integrity reasons Squid by default performs
3498 sanity checks of the addresses of FTP data connections ensure the
3499 data connection is to the requested server. If you need to allow
3500 FTP connections to servers using another IP address for the data
3501 connection turn this off.
3504 NAME: ftp_telnet_protocol
3507 LOC: Config.Ftp.telnet
3509 The FTP protocol is officially defined to use the telnet protocol
3510 as transport channel for the control connection. However, many
3511 implementations are broken and does not respect this aspect of
3514 If you have trouble accessing files with ASCII code 255 in the
3515 path or similar problems involving this ASCII code you can
3516 try setting this directive to off. If that helps, report to the
3517 operator of the FTP server in question that their FTP server
3518 is broken and does not follow the FTP standard.
3522 OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
3523 -----------------------------------------------------------------------------
3528 DEFAULT: @DEFAULT_DISKD@
3529 LOC: Config.Program.diskd
3531 Specify the location of the diskd executable.
3532 Note this is only useful if you have compiled in
3533 diskd as one of the store io modules.
3536 NAME: unlinkd_program
3539 DEFAULT: @DEFAULT_UNLINKD@
3540 LOC: Config.Program.unlinkd
3542 Specify the location of the executable for file deletion process.
3545 NAME: pinger_program
3547 DEFAULT: @DEFAULT_PINGER@
3548 LOC: Config.pinger.program
3551 Specify the location of the executable for the pinger process.
3557 LOC: Config.pinger.enable
3560 Control whether the pinger is active at run-time.
3561 Enables turning ICMP pinger on and off with a simple
3562 squid -k reconfigure.
3567 OPTIONS FOR URL REWRITING
3568 -----------------------------------------------------------------------------
3571 NAME: url_rewrite_program redirect_program
3573 LOC: Config.Program.redirect
3576 Specify the location of the executable for the URL rewriter.
3577 Since they can perform almost any function there isn't one included.
3579 For each requested URL rewriter will receive on line with the format
3581 URL <SP> client_ip "/" fqdn <SP> user <SP> method [<SP> kvpairs]<NL>
3583 In the future, the rewriter interface will be extended with
3584 key=value pairs ("kvpairs" shown above). Rewriter programs
3585 should be prepared to receive and possibly ignore additional
3586 whitespace-separated tokens on each input line.
3588 And the rewriter may return a rewritten URL. The other components of
3589 the request line does not need to be returned (ignored if they are).
3591 The rewriter can also indicate that a client-side redirect should
3592 be performed to the new URL. This is done by prefixing the returned
3593 URL with "301:" (moved permanently) or 302: (moved temporarily).
3595 By default, a URL rewriter is not used.
3598 NAME: url_rewrite_children redirect_children
3599 TYPE: HelperChildConfig
3600 DEFAULT: 20 startup=0 idle=1 concurrency=0
3601 LOC: Config.redirectChildren
3603 The maximum number of redirector processes to spawn. If you limit
3604 it too few Squid will have to wait for them to process a backlog of
3605 URLs, slowing it down. If you allow too many they will use RAM
3606 and other system resources noticably.
3608 The startup= and idle= options allow some measure of skew in your
3613 Sets a minimum of how many processes are to be spawned when Squid
3614 starts or reconfigures. When set to zero the first request will
3615 cause spawning of the first child process to handle it.
3617 Starting too few will cause an initial slowdown in traffic as Squid
3618 attempts to simultaneously spawn enough processes to cope.
3622 Sets a minimum of how many processes Squid is to try and keep available
3623 at all times. When traffic begins to rise above what the existing
3624 processes can handle this many more will be spawned up to the maximum
3625 configured. A minimum setting of 1 is required.
3629 The number of requests each redirector helper can handle in
3630 parallel. Defaults to 0 which indicates the redirector
3631 is a old-style single threaded redirector.
3633 When this directive is set to a value >= 1 then the protocol
3634 used to communicate with the helper is modified to include
3635 a request ID in front of the request/response. The request
3636 ID from the request must be echoed back with the response
3640 NAME: url_rewrite_host_header redirect_rewrites_host_header
3643 LOC: Config.onoff.redir_rewrites_host
3645 By default Squid rewrites any Host: header in redirected
3646 requests. If you are running an accelerator this may
3647 not be a wanted effect of a redirector.
3649 WARNING: Entries are cached on the result of the URL rewriting
3650 process, so be careful if you have domain-virtual hosts.
3653 NAME: url_rewrite_access redirector_access
3656 LOC: Config.accessList.redirector
3658 If defined, this access list specifies which requests are
3659 sent to the redirector processes. By default all requests
3662 This clause supports both fast and slow acl types.
3663 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
3666 NAME: url_rewrite_bypass redirector_bypass
3668 LOC: Config.onoff.redirector_bypass
3671 When this is 'on', a request will not go through the
3672 redirector if all redirectors are busy. If this is 'off'
3673 and the redirector queue grows too large, Squid will exit
3674 with a FATAL error and ask you to increase the number of
3675 redirectors. You should only enable this if the redirectors
3676 are not critical to your caching system. If you use
3677 redirectors for access control, and you enable this option,
3678 users may have access to pages they should not
3679 be allowed to request.
3683 OPTIONS FOR TUNING THE CACHE
3684 -----------------------------------------------------------------------------
3687 NAME: cache no_cache
3690 LOC: Config.accessList.noCache
3692 A list of ACL elements which, if matched and denied, cause the request to
3693 not be satisfied from the cache and the reply to not be cached.
3694 In other words, use this to force certain objects to never be cached.
3696 You must use the words 'allow' or 'deny' to indicate whether items
3697 matching the ACL should be allowed or denied into the cache.
3699 Default is to allow all to be cached.
3701 This clause supports both fast and slow acl types.
3702 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
3705 NAME: refresh_pattern
3706 TYPE: refreshpattern
3710 usage: refresh_pattern [-i] regex min percent max [options]
3712 By default, regular expressions are CASE-SENSITIVE. To make
3713 them case-insensitive, use the -i option.
3715 'Min' is the time (in minutes) an object without an explicit
3716 expiry time should be considered fresh. The recommended
3717 value is 0, any higher values may cause dynamic applications
3718 to be erroneously cached unless the application designer
3719 has taken the appropriate actions.
3721 'Percent' is a percentage of the objects age (time since last
3722 modification age) an object without explicit expiry time
3723 will be considered fresh.
3725 'Max' is an upper limit on how long objects without an explicit
3726 expiry time will be considered fresh.
3728 options: override-expire
3734 ignore-must-revalidate
3740 override-expire enforces min age even if the server
3741 sent an explicit expiry time (e.g., with the
3742 Expires: header or Cache-Control: max-age). Doing this
3743 VIOLATES the HTTP standard. Enabling this feature
3744 could make you liable for problems which it causes.
3746 Note: override-expire does not enforce staleness - it only extends
3747 freshness / min. If the server returns a Expires time which
3748 is longer than your max time, Squid will still consider
3749 the object fresh for that period of time.
3751 override-lastmod enforces min age even on objects
3752 that were modified recently.
3754 reload-into-ims changes client no-cache or ``reload''
3755 to If-Modified-Since requests. Doing this VIOLATES the
3756 HTTP standard. Enabling this feature could make you
3757 liable for problems which it causes.
3759 ignore-reload ignores a client no-cache or ``reload''
3760 header. Doing this VIOLATES the HTTP standard. Enabling
3761 this feature could make you liable for problems which
3764 ignore-no-cache ignores any ``Pragma: no-cache'' and
3765 ``Cache-control: no-cache'' headers received from a server.
3766 The HTTP RFC never allows the use of this (Pragma) header
3767 from a server, only a client, though plenty of servers
3770 ignore-no-store ignores any ``Cache-control: no-store''
3771 headers received from a server. Doing this VIOLATES
3772 the HTTP standard. Enabling this feature could make you
3773 liable for problems which it causes.
3775 ignore-must-revalidate ignores any ``Cache-Control: must-revalidate``
3776 headers received from a server. Doing this VIOLATES
3777 the HTTP standard. Enabling this feature could make you
3778 liable for problems which it causes.
3780 ignore-private ignores any ``Cache-control: private''
3781 headers received from a server. Doing this VIOLATES
3782 the HTTP standard. Enabling this feature could make you
3783 liable for problems which it causes.
3785 ignore-auth caches responses to requests with authorization,
3786 as if the originserver had sent ``Cache-control: public''
3787 in the response header. Doing this VIOLATES the HTTP standard.
3788 Enabling this feature could make you liable for problems which
3791 refresh-ims causes squid to contact the origin server
3792 when a client issues an If-Modified-Since request. This
3793 ensures that the client will receive an updated version
3794 if one is available.
3796 store-stale stores responses even if they don't have explicit
3797 freshness or a validator (i.e., Last-Modified or an ETag)
3798 present, or if they're already stale. By default, Squid will
3799 not cache such responses because they usually can't be
3800 reused. Note that such responses will be stale by default.
3802 Basically a cached object is:
3804 FRESH if expires < now, else STALE
3806 FRESH if lm-factor < percent, else STALE
3810 The refresh_pattern lines are checked in the order listed here.
3811 The first entry which matches is used. If none of the entries
3812 match the default will be used.
3814 Note, you must uncomment all the default lines if you want
3815 to change one. The default setting is only active if none is
3820 # Add any of your own refresh_pattern entries above these.
3821 refresh_pattern ^ftp: 1440 20% 10080
3822 refresh_pattern ^gopher: 1440 0% 1440
3823 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0
3824 refresh_pattern . 0 20% 4320
3828 NAME: quick_abort_min
3832 LOC: Config.quickAbort.min
3835 NAME: quick_abort_max
3839 LOC: Config.quickAbort.max
3842 NAME: quick_abort_pct
3846 LOC: Config.quickAbort.pct
3848 The cache by default continues downloading aborted requests
3849 which are almost completed (less than 16 KB remaining). This
3850 may be undesirable on slow (e.g. SLIP) links and/or very busy
3851 caches. Impatient users may tie up file descriptors and
3852 bandwidth by repeatedly requesting and immediately aborting
3855 When the user aborts a request, Squid will check the
3856 quick_abort values to the amount of data transfered until
3859 If the transfer has less than 'quick_abort_min' KB remaining,
3860 it will finish the retrieval.
3862 If the transfer has more than 'quick_abort_max' KB remaining,
3863 it will abort the retrieval.
3865 If more than 'quick_abort_pct' of the transfer has completed,
3866 it will finish the retrieval.
3868 If you do not want any retrieval to continue after the client
3869 has aborted, set both 'quick_abort_min' and 'quick_abort_max'
3872 If you want retrievals to always continue if they are being
3873 cached set 'quick_abort_min' to '-1 KB'.
3876 NAME: read_ahead_gap
3877 COMMENT: buffer-size
3879 LOC: Config.readAheadGap
3882 The amount of data the cache will buffer ahead of what has been
3883 sent to the client when retrieving an object from another server.
3887 IFDEF: USE_HTTP_VIOLATIONS
3890 LOC: Config.negativeTtl
3893 Set the Default Time-to-Live (TTL) for failed requests.
3894 Certain types of failures (such as "connection refused" and
3895 "404 Not Found") are able to be negatively-cached for a short time.
3896 Modern web servers should provide Expires: header, however if they
3897 do not this can provide a minimum TTL.
3898 The default is not to cache errors with unknown expiry details.
3900 Note that this is different from negative caching of DNS lookups.
3902 WARNING: Doing this VIOLATES the HTTP standard. Enabling
3903 this feature could make you liable for problems which it
3907 NAME: positive_dns_ttl
3910 LOC: Config.positiveDnsTtl
3913 Upper limit on how long Squid will cache positive DNS responses.
3914 Default is 6 hours (360 minutes). This directive must be set
3915 larger than negative_dns_ttl.
3918 NAME: negative_dns_ttl
3921 LOC: Config.negativeDnsTtl
3924 Time-to-Live (TTL) for negative caching of failed DNS lookups.
3925 This also sets the lower cache limit on positive lookups.
3926 Minimum value is 1 second, and it is not recommendable to go
3927 much below 10 seconds.
3930 NAME: range_offset_limit
3931 COMMENT: size [acl acl...]
3933 LOC: Config.rangeOffsetLimit
3936 usage: (size) [units] [[!]aclname]
3938 Sets an upper limit on how far (number of bytes) into the file
3939 a Range request may be to cause Squid to prefetch the whole file.
3940 If beyond this limit, Squid forwards the Range request as it is and
3941 the result is NOT cached.
3943 This is to stop a far ahead range request (lets say start at 17MB)
3944 from making Squid fetch the whole object up to that point before
3945 sending anything to the client.
3947 Multiple range_offset_limit lines may be specified, and they will
3948 be searched from top to bottom on each request until a match is found.
3949 The first match found will be used. If no line matches a request, the
3950 default limit of 0 bytes will be used.
3952 'size' is the limit specified as a number of units.
3954 'units' specifies whether to use bytes, KB, MB, etc.
3955 If no units are specified bytes are assumed.
3957 A size of 0 causes Squid to never fetch more than the
3958 client requested. (default)
3960 A size of 'none' causes Squid to always fetch the object from the
3961 beginning so it may cache the result. (2.0 style)
3963 'aclname' is the name of a defined ACL.
3965 NP: Using 'none' as the byte value here will override any quick_abort settings
3966 that may otherwise apply to the range request. The range request will
3967 be fully fetched from start to finish regardless of the client
3968 actions. This affects bandwidth usage.
3971 NAME: minimum_expiry_time
3974 LOC: Config.minimum_expiry_time
3977 The minimum caching time according to (Expires - Date)
3978 Headers Squid honors if the object can't be revalidated
3979 defaults to 60 seconds. In reverse proxy environments it
3980 might be desirable to honor shorter object lifetimes. It
3981 is most likely better to make your server return a
3982 meaningful Last-Modified header however. In ESI environments
3983 where page fragments often have short lifetimes, this will
3984 often be best set to 0.
3987 NAME: store_avg_object_size
3991 LOC: Config.Store.avgObjectSize
3993 Average object size, used to estimate number of objects your
3994 cache can hold. The default is 13 KB.
3997 NAME: store_objects_per_bucket
4000 LOC: Config.Store.objectsPerBucket
4002 Target number of objects per bucket in the store hash table.
4003 Lowering this value increases the total number of buckets and
4004 also the storage maintenance rate. The default is 20.
4009 -----------------------------------------------------------------------------
4012 NAME: request_header_max_size
4016 LOC: Config.maxRequestHeaderSize
4018 This specifies the maximum size for HTTP headers in a request.
4019 Request headers are usually relatively small (about 512 bytes).
4020 Placing a limit on the request header size will catch certain
4021 bugs (for example with persistent connections) and possibly
4022 buffer-overflow or denial-of-service attacks.
4025 NAME: reply_header_max_size
4029 LOC: Config.maxReplyHeaderSize
4031 This specifies the maximum size for HTTP headers in a reply.
4032 Reply headers are usually relatively small (about 512 bytes).
4033 Placing a limit on the reply header size will catch certain
4034 bugs (for example with persistent connections) and possibly
4035 buffer-overflow or denial-of-service attacks.
4038 NAME: request_body_max_size
4042 LOC: Config.maxRequestBodySize
4044 This specifies the maximum size for an HTTP request body.
4045 In other words, the maximum size of a PUT/POST request.
4046 A user who attempts to send a request with a body larger
4047 than this limit receives an "Invalid Request" error message.
4048 If you set this parameter to a zero (the default), there will
4049 be no limit imposed.
4052 NAME: chunked_request_body_max_size
4056 LOC: Config.maxChunkedRequestBodySize
4058 A broken or confused HTTP/1.1 client may send a chunked HTTP
4059 request to Squid. Squid does not have full support for that
4060 feature yet. To cope with such requests, Squid buffers the
4061 entire request and then dechunks request body to create a
4062 plain HTTP/1.0 request with a known content length. The plain
4063 request is then used by the rest of Squid code as usual.
4065 The option value specifies the maximum size of the buffer used
4066 to hold the request before the conversion. If the chunked
4067 request size exceeds the specified limit, the conversion
4068 fails, and the client receives an "unsupported request" error,
4069 as if dechunking was disabled.
4071 Dechunking is enabled by default. To disable conversion of
4072 chunked requests, set the maximum to zero.
4074 Request dechunking feature and this option in particular are a
4075 temporary hack. When chunking requests and responses are fully
4076 supported, there will be no need to buffer a chunked request.
4080 IFDEF: USE_HTTP_VIOLATIONS
4083 LOC: Config.accessList.brokenPosts
4085 A list of ACL elements which, if matched, causes Squid to send
4086 an extra CRLF pair after the body of a PUT/POST request.
4088 Some HTTP servers has broken implementations of PUT/POST,
4089 and rely on an extra CRLF pair sent by some WWW clients.
4091 Quote from RFC2616 section 4.1 on this matter:
4093 Note: certain buggy HTTP/1.0 client implementations generate an
4094 extra CRLF's after a POST request. To restate what is explicitly
4095 forbidden by the BNF, an HTTP/1.1 client must not preface or follow
4096 a request with an extra CRLF.
4098 This clause only supports fast acl types.
4099 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4102 acl buggy_server url_regex ^http://....
4103 broken_posts allow buggy_server
4106 NAME: adaptation_uses_indirect_client icap_uses_indirect_client
4109 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_ADAPTATION
4111 LOC: Adaptation::Config::use_indirect_client
4113 Controls whether the indirect client address
4114 (see follow_x_forwarded_for) instead of the
4115 direct client address is passed to an ICAP
4116 server as "X-Client-IP".
4120 IFDEF: USE_HTTP_VIOLATIONS
4124 LOC: Config.onoff.via
4126 If set (default), Squid will include a Via header in requests and
4127 replies as required by RFC2616.
4133 LOC: Config.onoff.ie_refresh
4136 Microsoft Internet Explorer up until version 5.5 Service
4137 Pack 1 has an issue with transparent proxies, wherein it
4138 is impossible to force a refresh. Turning this on provides
4139 a partial fix to the problem, by causing all IMS-REFRESH
4140 requests from older IE versions to check the origin server
4141 for fresh content. This reduces hit ratio by some amount
4142 (~10% in my experience), but allows users to actually get
4143 fresh content when they want it. Note because Squid
4144 cannot tell if the user is using 5.5 or 5.5SP1, the behavior
4145 of 5.5 is unchanged from old versions of Squid (i.e. a
4146 forced refresh is impossible). Newer versions of IE will,
4147 hopefully, continue to have the new behavior and will be
4148 handled based on that assumption. This option defaults to
4149 the old Squid behavior, which is better for hit ratios but
4150 worse for clients using IE, if they need to be able to
4151 force fresh content.
4154 NAME: vary_ignore_expire
4157 LOC: Config.onoff.vary_ignore_expire
4160 Many HTTP servers supporting Vary gives such objects
4161 immediate expiry time with no cache-control header
4162 when requested by a HTTP/1.0 client. This option
4163 enables Squid to ignore such expiry times until
4164 HTTP/1.1 is fully implemented.
4166 WARNING: If turned on this may eventually cause some
4167 varying objects not intended for caching to get cached.
4170 NAME: request_entities
4172 LOC: Config.onoff.request_entities
4175 Squid defaults to deny GET and HEAD requests with request entities,
4176 as the meaning of such requests are undefined in the HTTP standard
4177 even if not explicitly forbidden.
4179 Set this directive to on if you have clients which insists
4180 on sending request entities in GET or HEAD requests. But be warned
4181 that there is server software (both proxies and web servers) which
4182 can fail to properly process this kind of request which may make you
4183 vulnerable to cache pollution attacks if enabled.
4186 NAME: request_header_access
4187 IFDEF: USE_HTTP_VIOLATIONS
4188 TYPE: http_header_access[]
4189 LOC: Config.request_header_access
4192 Usage: request_header_access header_name allow|deny [!]aclname ...
4194 WARNING: Doing this VIOLATES the HTTP standard. Enabling
4195 this feature could make you liable for problems which it
4198 This option replaces the old 'anonymize_headers' and the
4199 older 'http_anonymizer' option with something that is much
4200 more configurable. This new method creates a list of ACLs
4201 for each header, allowing you very fine-tuned header
4204 This option only applies to request headers, i.e., from the
4205 client to the server.
4207 You can only specify known headers for the header name.
4208 Other headers are reclassified as 'Other'. You can also
4209 refer to all the headers with 'All'.
4211 For example, to achieve the same behavior as the old
4212 'http_anonymizer standard' option, you should use:
4214 request_header_access From deny all
4215 request_header_access Referer deny all
4216 request_header_access Server deny all
4217 request_header_access User-Agent deny all
4218 request_header_access WWW-Authenticate deny all
4219 request_header_access Link deny all
4221 Or, to reproduce the old 'http_anonymizer paranoid' feature
4224 request_header_access Allow allow all
4225 request_header_access Authorization allow all
4226 request_header_access WWW-Authenticate allow all
4227 request_header_access Proxy-Authorization allow all
4228 request_header_access Proxy-Authenticate allow all
4229 request_header_access Cache-Control allow all
4230 request_header_access Content-Encoding allow all
4231 request_header_access Content-Length allow all
4232 request_header_access Content-Type allow all
4233 request_header_access Date allow all
4234 request_header_access Expires allow all
4235 request_header_access Host allow all
4236 request_header_access If-Modified-Since allow all
4237 request_header_access Last-Modified allow all
4238 request_header_access Location allow all
4239 request_header_access Pragma allow all
4240 request_header_access Accept allow all
4241 request_header_access Accept-Charset allow all
4242 request_header_access Accept-Encoding allow all
4243 request_header_access Accept-Language allow all
4244 request_header_access Content-Language allow all
4245 request_header_access Mime-Version allow all
4246 request_header_access Retry-After allow all
4247 request_header_access Title allow all
4248 request_header_access Connection allow all
4249 request_header_access All deny all
4251 although many of those are HTTP reply headers, and so should be
4252 controlled with the reply_header_access directive.
4254 By default, all headers are allowed (no anonymizing is
4258 NAME: reply_header_access
4259 IFDEF: USE_HTTP_VIOLATIONS
4260 TYPE: http_header_access[]
4261 LOC: Config.reply_header_access
4264 Usage: reply_header_access header_name allow|deny [!]aclname ...
4266 WARNING: Doing this VIOLATES the HTTP standard. Enabling
4267 this feature could make you liable for problems which it
4270 This option only applies to reply headers, i.e., from the
4271 server to the client.
4273 This is the same as request_header_access, but in the other
4276 This option replaces the old 'anonymize_headers' and the
4277 older 'http_anonymizer' option with something that is much
4278 more configurable. This new method creates a list of ACLs
4279 for each header, allowing you very fine-tuned header
4282 You can only specify known headers for the header name.
4283 Other headers are reclassified as 'Other'. You can also
4284 refer to all the headers with 'All'.
4286 For example, to achieve the same behavior as the old
4287 'http_anonymizer standard' option, you should use:
4289 reply_header_access From deny all
4290 reply_header_access Referer deny all
4291 reply_header_access Server deny all
4292 reply_header_access User-Agent deny all
4293 reply_header_access WWW-Authenticate deny all
4294 reply_header_access Link deny all
4296 Or, to reproduce the old 'http_anonymizer paranoid' feature
4299 reply_header_access Allow allow all
4300 reply_header_access Authorization allow all
4301 reply_header_access WWW-Authenticate allow all
4302 reply_header_access Proxy-Authorization allow all
4303 reply_header_access Proxy-Authenticate allow all
4304 reply_header_access Cache-Control allow all
4305 reply_header_access Content-Encoding allow all
4306 reply_header_access Content-Length allow all
4307 reply_header_access Content-Type allow all
4308 reply_header_access Date allow all
4309 reply_header_access Expires allow all
4310 reply_header_access Host allow all
4311 reply_header_access If-Modified-Since allow all
4312 reply_header_access Last-Modified allow all
4313 reply_header_access Location allow all
4314 reply_header_access Pragma allow all
4315 reply_header_access Accept allow all
4316 reply_header_access Accept-Charset allow all
4317 reply_header_access Accept-Encoding allow all
4318 reply_header_access Accept-Language allow all
4319 reply_header_access Content-Language allow all
4320 reply_header_access Mime-Version allow all
4321 reply_header_access Retry-After allow all
4322 reply_header_access Title allow all
4323 reply_header_access Connection allow all
4324 reply_header_access All deny all
4326 although the HTTP request headers won't be usefully controlled
4327 by this directive -- see request_header_access for details.
4329 By default, all headers are allowed (no anonymizing is
4333 NAME: header_replace
4334 IFDEF: USE_HTTP_VIOLATIONS
4335 TYPE: http_header_replace[]
4336 LOC: Config.request_header_access
4339 Usage: header_replace header_name message
4340 Example: header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
4342 This option allows you to change the contents of headers
4343 denied with header_access above, by replacing them with
4344 some fixed string. This replaces the old fake_user_agent
4347 This only applies to request headers, not reply headers.
4349 By default, headers are removed if denied.
4352 NAME: relaxed_header_parser
4353 COMMENT: on|off|warn
4355 LOC: Config.onoff.relaxed_header_parser
4358 In the default "on" setting Squid accepts certain forms
4359 of non-compliant HTTP messages where it is unambiguous
4360 what the sending application intended even if the message
4361 is not correctly formatted. The messages is then normalized
4362 to the correct form when forwarded by Squid.
4364 If set to "warn" then a warning will be emitted in cache.log
4365 each time such HTTP error is encountered.
4367 If set to "off" then such HTTP errors will cause the request
4368 or response to be rejected.
4373 -----------------------------------------------------------------------------
4376 NAME: forward_timeout
4379 LOC: Config.Timeout.forward
4382 This parameter specifies how long Squid should at most attempt in
4383 finding a forwarding path for the request before giving up.
4386 NAME: connect_timeout
4389 LOC: Config.Timeout.connect
4392 This parameter specifies how long to wait for the TCP connect to
4393 the requested server or peer to complete before Squid should
4394 attempt to find another path where to forward the request.
4397 NAME: peer_connect_timeout
4400 LOC: Config.Timeout.peer_connect
4403 This parameter specifies how long to wait for a pending TCP
4404 connection to a peer cache. The default is 30 seconds. You
4405 may also set different timeout values for individual neighbors
4406 with the 'connect-timeout' option on a 'cache_peer' line.
4412 LOC: Config.Timeout.read
4415 The read_timeout is applied on server-side connections. After
4416 each successful read(), the timeout will be extended by this
4417 amount. If no data is read again after this amount of time,
4418 the request is aborted and logged with ERR_READ_TIMEOUT. The
4419 default is 15 minutes.
4425 LOC: Config.Timeout.write
4428 This timeout is tracked for all connections that have data
4429 available for writing and are waiting for the socket to become
4430 ready. After each successful write, the timeout is extended by
4431 the configured amount. If Squid has data to write but the
4432 connection is not ready for the configured duration, the
4433 transaction associated with the connection is terminated. The
4434 default is 15 minutes.
4437 NAME: request_timeout
4439 LOC: Config.Timeout.request
4442 How long to wait for an HTTP request after initial
4443 connection establishment.
4446 NAME: persistent_request_timeout
4448 LOC: Config.Timeout.persistent_request
4451 How long to wait for the next HTTP request on a persistent
4452 connection after the previous request completes.
4455 NAME: client_lifetime
4458 LOC: Config.Timeout.lifetime
4461 The maximum amount of time a client (browser) is allowed to
4462 remain connected to the cache process. This protects the Cache
4463 from having a lot of sockets (and hence file descriptors) tied up
4464 in a CLOSE_WAIT state from remote clients that go away without
4465 properly shutting down (either because of a network failure or
4466 because of a poor client implementation). The default is one
4469 NOTE: The default value is intended to be much larger than any
4470 client would ever need to be connected to your cache. You
4471 should probably change client_lifetime only as a last resort.
4472 If you seem to have many client connections tying up
4473 filedescriptors, we recommend first tuning the read_timeout,
4474 request_timeout, persistent_request_timeout and quick_abort values.
4477 NAME: half_closed_clients
4479 LOC: Config.onoff.half_closed_clients
4482 Some clients may shutdown the sending side of their TCP
4483 connections, while leaving their receiving sides open. Sometimes,
4484 Squid can not tell the difference between a half-closed and a
4485 fully-closed TCP connection.
4487 By default, Squid will immediately close client connections when
4488 read(2) returns "no more data to read."
4490 Change this option to 'on' and Squid will keep open connections
4491 until a read(2) or write(2) on the socket returns an error.
4492 This may show some benefits for reverse proxies. But if not
4493 it is recommended to leave OFF.
4498 LOC: Config.Timeout.pconn
4501 Timeout for idle persistent connections to servers and other
4508 LOC: Ident::TheConfig.timeout
4511 Maximum time to wait for IDENT lookups to complete.
4513 If this is too high, and you enabled IDENT lookups from untrusted
4514 users, you might be susceptible to denial-of-service by having
4515 many ident requests going at once.
4518 NAME: shutdown_lifetime
4521 LOC: Config.shutdownLifetime
4524 When SIGTERM or SIGHUP is received, the cache is put into
4525 "shutdown pending" mode until all active sockets are closed.
4526 This value is the lifetime to set for all open descriptors
4527 during shutdown mode. Any active clients after this many
4528 seconds will receive a 'timeout' message.
4532 ADMINISTRATIVE PARAMETERS
4533 -----------------------------------------------------------------------------
4539 LOC: Config.adminEmail
4541 Email-address of local cache manager who will receive
4542 mail if the cache dies. The default is "webmaster."
4548 LOC: Config.EmailFrom
4550 From: email-address for mail sent when the cache dies.
4551 The default is to use 'appname@unique_hostname'.
4552 Default appname value is "squid", can be changed into
4553 src/globals.h before building squid.
4559 LOC: Config.EmailProgram
4561 Email program used to send mail if the cache dies.
4562 The default is "mail". The specified program must comply
4563 with the standard Unix mail syntax:
4564 mail-program recipient < mailfile
4566 Optional command line options can be specified.
4569 NAME: cache_effective_user
4571 DEFAULT: @DEFAULT_CACHE_EFFECTIVE_USER@
4572 LOC: Config.effectiveUser
4574 If you start Squid as root, it will change its effective/real
4575 UID/GID to the user specified below. The default is to change
4576 to UID of @DEFAULT_CACHE_EFFECTIVE_USER@.
4577 see also; cache_effective_group
4580 NAME: cache_effective_group
4583 LOC: Config.effectiveGroup
4585 Squid sets the GID to the effective user's default group ID
4586 (taken from the password file) and supplementary group list
4587 from the groups membership.
4589 If you want Squid to run with a specific GID regardless of
4590 the group memberships of the effective user then set this
4591 to the group (or GID) you want Squid to run as. When set
4592 all other group privileges of the effective user are ignored
4593 and only this GID is effective. If Squid is not started as
4594 root the user starting Squid MUST be member of the specified
4597 This option is not recommended by the Squid Team.
4598 Our preference is for administrators to configure a secure
4599 user account for squid with UID/GID matching system policies.
4602 NAME: httpd_suppress_version_string
4606 LOC: Config.onoff.httpd_suppress_version_string
4608 Suppress Squid version string info in HTTP headers and HTML error pages.
4611 NAME: visible_hostname
4613 LOC: Config.visibleHostname
4616 If you want to present a special hostname in error messages, etc,
4617 define this. Otherwise, the return value of gethostname()
4618 will be used. If you have multiple caches in a cluster and
4619 get errors about IP-forwarding you must set them to have individual
4620 names with this setting.
4623 NAME: unique_hostname
4625 LOC: Config.uniqueHostname
4628 If you want to have multiple machines with the same
4629 'visible_hostname' you must give each machine a different
4630 'unique_hostname' so forwarding loops can be detected.
4633 NAME: hostname_aliases
4635 LOC: Config.hostnameAliases
4638 A list of other DNS names your cache has.
4646 Minimum umask which should be enforced while the proxy
4647 is running, in addition to the umask set at startup.
4649 For a traditional octal representation of umasks, start
4654 OPTIONS FOR THE CACHE REGISTRATION SERVICE
4655 -----------------------------------------------------------------------------
4657 This section contains parameters for the (optional) cache
4658 announcement service. This service is provided to help
4659 cache administrators locate one another in order to join or
4660 create cache hierarchies.
4662 An 'announcement' message is sent (via UDP) to the registration
4663 service by Squid. By default, the announcement message is NOT
4664 SENT unless you enable it with 'announce_period' below.
4666 The announcement message includes your hostname, plus the
4667 following information from this configuration file:
4673 All current information is processed regularly and made
4674 available on the Web at http://www.ircache.net/Cache/Tracker/.
4677 NAME: announce_period
4679 LOC: Config.Announce.period
4682 This is how frequently to send cache announcements. The
4683 default is `0' which disables sending the announcement
4686 To enable announcing your cache, just set an announce period.
4689 announce_period 1 day
4694 DEFAULT: tracker.ircache.net
4695 LOC: Config.Announce.host
4701 LOC: Config.Announce.file
4707 LOC: Config.Announce.port
4709 announce_host and announce_port set the hostname and port
4710 number where the registration message will be sent.
4712 Hostname will default to 'tracker.ircache.net' and port will
4713 default default to 3131. If the 'filename' argument is given,
4714 the contents of that file will be included in the announce
4719 HTTPD-ACCELERATOR OPTIONS
4720 -----------------------------------------------------------------------------
4723 NAME: httpd_accel_surrogate_id
4726 LOC: Config.Accel.surrogate_id
4728 Surrogates (http://www.esi.org/architecture_spec_1.0.html)
4729 need an identification token to allow control targeting. Because
4730 a farm of surrogates may all perform the same tasks, they may share
4731 an identification token.
4733 The default ID is the visible_hostname
4736 NAME: http_accel_surrogate_remote
4740 LOC: Config.onoff.surrogate_is_remote
4742 Remote surrogates (such as those in a CDN) honour Surrogate-Control: no-store-remote.
4743 Set this to on to have squid behave as a remote surrogate.
4747 IFDEF: USE_SQUID_ESI
4748 COMMENT: libxml2|expat|custom
4750 LOC: ESIParser::Type
4753 ESI markup is not strictly XML compatible. The custom ESI parser
4754 will give higher performance, but cannot handle non ASCII character
4759 DELAY POOL PARAMETERS
4760 -----------------------------------------------------------------------------
4764 TYPE: delay_pool_count
4766 IFDEF: USE_DELAY_POOLS
4769 This represents the number of delay pools to be used. For example,
4770 if you have one class 2 delay pool and one class 3 delays pool, you
4771 have a total of 2 delay pools.
4775 TYPE: delay_pool_class
4777 IFDEF: USE_DELAY_POOLS
4780 This defines the class of each delay pool. There must be exactly one
4781 delay_class line for each delay pool. For example, to define two
4782 delay pools, one of class 2 and one of class 3, the settings above
4786 delay_pools 4 # 4 delay pools
4787 delay_class 1 2 # pool 1 is a class 2 pool
4788 delay_class 2 3 # pool 2 is a class 3 pool
4789 delay_class 3 4 # pool 3 is a class 4 pool
4790 delay_class 4 5 # pool 4 is a class 5 pool
4792 The delay pool classes are:
4794 class 1 Everything is limited by a single aggregate
4797 class 2 Everything is limited by a single aggregate
4798 bucket as well as an "individual" bucket chosen
4799 from bits 25 through 32 of the IPv4 address.
4801 class 3 Everything is limited by a single aggregate
4802 bucket as well as a "network" bucket chosen
4803 from bits 17 through 24 of the IP address and a
4804 "individual" bucket chosen from bits 17 through
4805 32 of the IPv4 address.
4807 class 4 Everything in a class 3 delay pool, with an
4808 additional limit on a per user basis. This
4809 only takes effect if the username is established
4810 in advance - by forcing authentication in your
4813 class 5 Requests are grouped according their tag (see
4814 external_acl's tag= reply).
4816 NOTE: If an IP address is a.b.c.d
4817 -> bits 25 through 32 are "d"
4818 -> bits 17 through 24 are "c"
4819 -> bits 17 through 32 are "c * 256 + d"
4821 NOTE-2: Due to the use of bitmasks in class 2,3,4 pools they only apply to
4822 IPv4 traffic. Class 1 and 5 pools may be used with IPv6 traffic.
4826 TYPE: delay_pool_access
4828 IFDEF: USE_DELAY_POOLS
4831 This is used to determine which delay pool a request falls into.
4833 delay_access is sorted per pool and the matching starts with pool 1,
4834 then pool 2, ..., and finally pool N. The first delay pool where the
4835 request is allowed is selected for the request. If it does not allow
4836 the request to any pool then the request is not delayed (default).
4838 For example, if you want some_big_clients in delay
4839 pool 1 and lotsa_little_clients in delay pool 2:
4842 delay_access 1 allow some_big_clients
4843 delay_access 1 deny all
4844 delay_access 2 allow lotsa_little_clients
4845 delay_access 2 deny all
4846 delay_access 3 allow authenticated_clients
4849 NAME: delay_parameters
4850 TYPE: delay_pool_rates
4852 IFDEF: USE_DELAY_POOLS
4855 This defines the parameters for a delay pool. Each delay pool has
4856 a number of "buckets" associated with it, as explained in the
4857 description of delay_class. For a class 1 delay pool, the syntax is:
4859 delay_parameters pool aggregate
4861 For a class 2 delay pool:
4863 delay_parameters pool aggregate individual
4865 For a class 3 delay pool:
4867 delay_parameters pool aggregate network individual
4869 For a class 4 delay pool:
4871 delay_parameters pool aggregate network individual user
4873 For a class 5 delay pool:
4875 delay_parameters pool tag
4877 The variables here are:
4879 pool a pool number - ie, a number between 1 and the
4880 number specified in delay_pools as used in
4883 aggregate the "delay parameters" for the aggregate bucket
4886 individual the "delay parameters" for the individual
4887 buckets (class 2, 3).
4889 network the "delay parameters" for the network buckets
4892 user the delay parameters for the user buckets
4895 tag the delay parameters for the tag buckets
4898 A pair of delay parameters is written restore/maximum, where restore is
4899 the number of bytes (not bits - modem and network speeds are usually
4900 quoted in bits) per second placed into the bucket, and maximum is the
4901 maximum number of bytes which can be in the bucket at any time.
4903 For example, if delay pool number 1 is a class 2 delay pool as in the
4904 above example, and is being used to strictly limit each host to 64kbps
4905 (plus overheads), with no overall limit, the line is:
4907 delay_parameters 1 -1/-1 8000/8000
4909 Note that the figure -1 is used to represent "unlimited".
4911 And, if delay pool number 2 is a class 3 delay pool as in the above
4912 example, and you want to limit it to a total of 256kbps (strict limit)
4913 with each 8-bit network permitted 64kbps (strict limit) and each
4914 individual host permitted 4800bps with a bucket maximum size of 64kb
4915 to permit a decent web page to be downloaded at a decent speed
4916 (if the network is not being limited due to overuse) but slow down
4917 large downloads more significantly:
4919 delay_parameters 2 32000/32000 8000/8000 600/8000
4921 There must be one delay_parameters line for each delay pool.
4923 Finally, for a class 4 delay pool as in the example - each user will
4924 be limited to 128Kb no matter how many workstations they are logged into.:
4926 delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000
4929 NAME: delay_initial_bucket_level
4930 COMMENT: (percent, 0-100)
4933 IFDEF: USE_DELAY_POOLS
4934 LOC: Config.Delay.initial
4936 The initial bucket percentage is used to determine how much is put
4937 in each bucket when squid starts, is reconfigured, or first notices
4938 a host accessing it (in class 2 and class 3, individual hosts and
4939 networks only have buckets associated with them once they have been
4944 CLIENT DELAY POOL PARAMETERS
4945 -----------------------------------------------------------------------------
4948 NAME: client_delay_pools
4949 TYPE: client_delay_pool_count
4951 IFDEF: USE_DELAY_POOLS
4952 LOC: Config.ClientDelay
4954 This option specifies the number of client delay pools used. It must
4955 preceed other client_delay_* options.
4958 client_delay_pools 2
4961 NAME: client_delay_initial_bucket_level
4962 COMMENT: (percent, 0-no_limit)
4965 IFDEF: USE_DELAY_POOLS
4966 LOC: Config.ClientDelay.initial
4968 This option determines the initial bucket size as a percentage of
4969 max_bucket_size from client_delay_parameters. Buckets are created
4970 at the time of the "first" connection from the matching IP. Idle
4971 buckets are periodically deleted up.
4973 You can specify more than 100 percent but note that such "oversized"
4974 buckets are not refilled until their size goes down to max_bucket_size
4975 from client_delay_parameters.
4978 client_delay_initial_bucket_level 50
4981 NAME: client_delay_parameters
4982 TYPE: client_delay_pool_rates
4984 IFDEF: USE_DELAY_POOLS
4985 LOC: Config.ClientDelay
4988 This option configures client-side bandwidth limits using the
4991 client_delay_parameters pool speed_limit max_bucket_size
4993 pool is an integer ID used for client_delay_access matching.
4995 speed_limit is bytes added to the bucket per second.
4997 max_bucket_size is the maximum size of a bucket, enforced after any
4998 speed_limit additions.
5000 Please see the delay_parameters option for more information and
5004 client_delay_parameters 1 1024 2048
5005 client_delay_parameters 2 51200 16384
5008 NAME: client_delay_access
5009 TYPE: client_delay_pool_access
5011 IFDEF: USE_DELAY_POOLS
5012 LOC: Config.ClientDelay
5015 This option determines the client-side delay pool for the
5018 client_delay_access pool_ID allow|deny acl_name
5020 All client_delay_access options are checked in their pool ID
5021 order, starting with pool 1. The first checked pool with allowed
5022 request is selected for the request. If no ACL matches or there
5023 are no client_delay_access options, the request bandwidth is not
5026 The ACL-selected pool is then used to find the
5027 client_delay_parameters for the request. Client-side pools are
5028 not used to aggregate clients. Clients are always aggregated
5029 based on their source IP addresses (one bucket per source IP).
5031 Please see delay_access for more examples.
5034 client_delay_access 1 allow low_rate_network
5035 client_delay_access 2 allow vips_network
5039 WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS
5040 -----------------------------------------------------------------------------
5045 LOC: Config.Wccp.router
5049 Use this option to define your WCCP ``home'' router for
5052 wccp_router supports a single WCCP(v1) router
5054 wccp2_router supports multiple WCCPv2 routers
5056 only one of the two may be used at the same time and defines
5057 which version of WCCP to use.
5061 TYPE: IpAddress_list
5062 LOC: Config.Wccp2.router
5066 Use this option to define your WCCP ``home'' router for
5069 wccp_router supports a single WCCP(v1) router
5071 wccp2_router supports multiple WCCPv2 routers
5073 only one of the two may be used at the same time and defines
5074 which version of WCCP to use.
5079 LOC: Config.Wccp.version
5083 This directive is only relevant if you need to set up WCCP(v1)
5084 to some very old and end-of-life Cisco routers. In all other
5085 setups it must be left unset or at the default setting.
5086 It defines an internal version in the WCCP(v1) protocol,
5087 with version 4 being the officially documented protocol.
5089 According to some users, Cisco IOS 11.2 and earlier only
5090 support WCCP version 3. If you're using that or an earlier
5091 version of IOS, you may need to change this value to 3, otherwise
5092 do not specify this parameter.
5095 NAME: wccp2_rebuild_wait
5097 LOC: Config.Wccp2.rebuildwait
5101 If this is enabled Squid will wait for the cache dir rebuild to finish
5102 before sending the first wccp2 HereIAm packet
5105 NAME: wccp2_forwarding_method
5107 LOC: Config.Wccp2.forwarding_method
5111 WCCP2 allows the setting of forwarding methods between the
5112 router/switch and the cache. Valid values are as follows:
5114 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
5115 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
5117 Currently (as of IOS 12.4) cisco routers only support GRE.
5118 Cisco switches only support the L2 redirect assignment method.
5121 NAME: wccp2_return_method
5123 LOC: Config.Wccp2.return_method
5127 WCCP2 allows the setting of return methods between the
5128 router/switch and the cache for packets that the cache
5129 decides not to handle. Valid values are as follows:
5131 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
5132 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
5134 Currently (as of IOS 12.4) cisco routers only support GRE.
5135 Cisco switches only support the L2 redirect assignment.
5137 If the "ip wccp redirect exclude in" command has been
5138 enabled on the cache interface, then it is still safe for
5139 the proxy server to use a l2 redirect method even if this
5140 option is set to GRE.
5143 NAME: wccp2_assignment_method
5145 LOC: Config.Wccp2.assignment_method
5149 WCCP2 allows the setting of methods to assign the WCCP hash
5150 Valid values are as follows:
5152 hash - Hash assignment
5153 mask - Mask assignment
5155 As a general rule, cisco routers support the hash assignment method
5156 and cisco switches support the mask assignment method.
5161 LOC: Config.Wccp2.info
5162 DEFAULT_IF_NONE: standard 0
5165 WCCP2 allows for multiple traffic services. There are two
5166 types: "standard" and "dynamic". The standard type defines
5167 one service id - http (id 0). The dynamic service ids can be from
5168 51 to 255 inclusive. In order to use a dynamic service id
5169 one must define the type of traffic to be redirected; this is done
5170 using the wccp2_service_info option.
5172 The "standard" type does not require a wccp2_service_info option,
5173 just specifying the service id will suffice.
5175 MD5 service authentication can be enabled by adding
5176 "password=<password>" to the end of this service declaration.
5180 wccp2_service standard 0 # for the 'web-cache' standard service
5181 wccp2_service dynamic 80 # a dynamic service type which will be
5182 # fleshed out with subsequent options.
5183 wccp2_service standard 0 password=foo
5186 NAME: wccp2_service_info
5187 TYPE: wccp2_service_info
5188 LOC: Config.Wccp2.info
5192 Dynamic WCCPv2 services require further information to define the
5193 traffic you wish to have diverted.
5197 wccp2_service_info <id> protocol=<protocol> flags=<flag>,<flag>..
5198 priority=<priority> ports=<port>,<port>..
5200 The relevant WCCPv2 flags:
5201 + src_ip_hash, dst_ip_hash
5202 + source_port_hash, dst_port_hash
5203 + src_ip_alt_hash, dst_ip_alt_hash
5204 + src_port_alt_hash, dst_port_alt_hash
5207 The port list can be one to eight entries.
5211 wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source
5212 priority=240 ports=80
5214 Note: the service id must have been defined by a previous
5215 'wccp2_service dynamic <id>' entry.
5220 LOC: Config.Wccp2.weight
5224 Each cache server gets assigned a set of the destination
5225 hash proportional to their weight.
5230 LOC: Config.Wccp.address
5237 LOC: Config.Wccp2.address
5241 Use this option if you require WCCP to use a specific
5244 The default behavior is to not bind to any specific address.
5248 PERSISTENT CONNECTION HANDLING
5249 -----------------------------------------------------------------------------
5251 Also see "pconn_timeout" in the TIMEOUTS section
5254 NAME: client_persistent_connections
5256 LOC: Config.onoff.client_pconns
5260 NAME: server_persistent_connections
5262 LOC: Config.onoff.server_pconns
5265 Persistent connection support for clients and servers. By
5266 default, Squid uses persistent connections (when allowed)
5267 with its clients and servers. You can use these options to
5268 disable persistent connections with clients and/or servers.
5271 NAME: persistent_connection_after_error
5273 LOC: Config.onoff.error_pconns
5276 With this directive the use of persistent connections after
5277 HTTP errors can be disabled. Useful if you have clients
5278 who fail to handle errors on persistent connections proper.
5281 NAME: detect_broken_pconn
5283 LOC: Config.onoff.detect_broken_server_pconns
5286 Some servers have been found to incorrectly signal the use
5287 of HTTP/1.0 persistent connections even on replies not
5288 compatible, causing significant delays. This server problem
5289 has mostly been seen on redirects.
5291 By enabling this directive Squid attempts to detect such
5292 broken replies and automatically assume the reply is finished
5293 after 10 seconds timeout.
5297 CACHE DIGEST OPTIONS
5298 -----------------------------------------------------------------------------
5301 NAME: digest_generation
5302 IFDEF: USE_CACHE_DIGESTS
5304 LOC: Config.onoff.digest_generation
5307 This controls whether the server will generate a Cache Digest
5308 of its contents. By default, Cache Digest generation is
5309 enabled if Squid is compiled with --enable-cache-digests defined.
5312 NAME: digest_bits_per_entry
5313 IFDEF: USE_CACHE_DIGESTS
5315 LOC: Config.digest.bits_per_entry
5318 This is the number of bits of the server's Cache Digest which
5319 will be associated with the Digest entry for a given HTTP
5320 Method and URL (public key) combination. The default is 5.
5323 NAME: digest_rebuild_period
5324 IFDEF: USE_CACHE_DIGESTS
5327 LOC: Config.digest.rebuild_period
5330 This is the wait time between Cache Digest rebuilds.
5333 NAME: digest_rewrite_period
5335 IFDEF: USE_CACHE_DIGESTS
5337 LOC: Config.digest.rewrite_period
5340 This is the wait time between Cache Digest writes to
5344 NAME: digest_swapout_chunk_size
5347 IFDEF: USE_CACHE_DIGESTS
5348 LOC: Config.digest.swapout_chunk_size
5351 This is the number of bytes of the Cache Digest to write to
5352 disk at a time. It defaults to 4096 bytes (4KB), the Squid
5356 NAME: digest_rebuild_chunk_percentage
5357 COMMENT: (percent, 0-100)
5358 IFDEF: USE_CACHE_DIGESTS
5360 LOC: Config.digest.rebuild_chunk_percentage
5363 This is the percentage of the Cache Digest to be scanned at a
5364 time. By default it is set to 10% of the Cache Digest.
5369 -----------------------------------------------------------------------------
5374 LOC: Config.Port.snmp
5378 The port number where Squid listens for SNMP requests. To enable
5379 SNMP support set this to a suitable port number. Port number
5380 3401 is often used for the Squid SNMP agent. By default it's
5381 set to "0" (disabled)
5389 LOC: Config.accessList.snmp
5390 DEFAULT_IF_NONE: deny all
5393 Allowing or denying access to the SNMP port.
5395 All access to the agent is denied by default.
5398 snmp_access allow|deny [!]aclname ...
5400 This clause only supports fast acl types.
5401 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5403 snmp_access allow snmppublic localhost
5404 snmp_access deny all
5407 NAME: snmp_incoming_address
5409 LOC: Config.Addrs.snmp_incoming
5414 NAME: snmp_outgoing_address
5416 LOC: Config.Addrs.snmp_outgoing
5420 Just like 'udp_incoming_address', but for the SNMP port.
5422 snmp_incoming_address is used for the SNMP socket receiving
5423 messages from SNMP agents.
5424 snmp_outgoing_address is used for SNMP packets returned to SNMP
5427 The default snmp_incoming_address is to listen on all
5428 available network interfaces.
5430 If snmp_outgoing_address is not set it will use the same socket
5431 as snmp_incoming_address. Only change this if you want to have
5432 SNMP replies sent using another address than where this Squid
5433 listens for SNMP queries.
5435 NOTE, snmp_incoming_address and snmp_outgoing_address can not have
5436 the same value since they both use port 3401.
5441 -----------------------------------------------------------------------------
5444 NAME: icp_port udp_port
5447 LOC: Config.Port.icp
5449 The port number where Squid sends and receives ICP queries to
5450 and from neighbor caches. The standard UDP port for ICP is 3130.
5451 Default is disabled (0).
5454 icp_port @DEFAULT_ICP_PORT@
5461 LOC: Config.Port.htcp
5463 The port number where Squid sends and receives HTCP queries to
5464 and from neighbor caches. To turn it on you want to set it to
5465 4827. By default it is set to "0" (disabled).
5471 NAME: log_icp_queries
5475 LOC: Config.onoff.log_udp
5477 If set, ICP queries are logged to access.log. You may wish
5478 do disable this if your ICP load is VERY high to speed things
5479 up or to simplify log analysis.
5482 NAME: udp_incoming_address
5484 LOC:Config.Addrs.udp_incoming
5487 udp_incoming_address is used for UDP packets received from other
5490 The default behavior is to not bind to any specific address.
5492 Only change this if you want to have all UDP queries received on
5493 a specific interface/address.
5495 NOTE: udp_incoming_address is used by the ICP, HTCP, and DNS
5496 modules. Altering it will affect all of them in the same manner.
5498 see also; udp_outgoing_address
5500 NOTE, udp_incoming_address and udp_outgoing_address can not
5501 have the same value since they both use the same port.
5504 NAME: udp_outgoing_address
5506 LOC: Config.Addrs.udp_outgoing
5509 udp_outgoing_address is used for UDP packets sent out to other
5512 The default behavior is to not bind to any specific address.
5514 Instead it will use the same socket as udp_incoming_address.
5515 Only change this if you want to have UDP queries sent using another
5516 address than where this Squid listens for UDP queries from other
5519 NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS
5520 modules. Altering it will affect all of them in the same manner.
5522 see also; udp_incoming_address
5524 NOTE, udp_incoming_address and udp_outgoing_address can not
5525 have the same value since they both use the same port.
5532 LOC: Config.onoff.icp_hit_stale
5534 If you want to return ICP_HIT for stale cache objects, set this
5535 option to 'on'. If you have sibling relationships with caches
5536 in other administrative domains, this should be 'off'. If you only
5537 have sibling relationships with caches under your control,
5538 it is probably okay to set this to 'on'.
5539 If set to 'on', your siblings should use the option "allow-miss"
5540 on their cache_peer lines for connecting to you.
5543 NAME: minimum_direct_hops
5546 LOC: Config.minDirectHops
5548 If using the ICMP pinging stuff, do direct fetches for sites
5549 which are no more than this many hops away.
5552 NAME: minimum_direct_rtt
5555 LOC: Config.minDirectRtt
5557 If using the ICMP pinging stuff, do direct fetches for sites
5558 which are no more than this many rtt milliseconds away.
5564 LOC: Config.Netdb.low
5570 LOC: Config.Netdb.high
5572 The low and high water marks for the ICMP measurement
5573 database. These are counts, not percents. The defaults are
5574 900 and 1000. When the high water mark is reached, database
5575 entries will be deleted until the low mark is reached.
5578 NAME: netdb_ping_period
5580 LOC: Config.Netdb.period
5583 The minimum period for measuring a site. There will be at
5584 least this much delay between successive pings to the same
5585 network. The default is five minutes.
5592 LOC: Config.onoff.query_icmp
5594 If you want to ask your peers to include ICMP data in their ICP
5595 replies, enable this option.
5597 If your peer has configured Squid (during compilation) with
5598 '--enable-icmp' that peer will send ICMP pings to origin server
5599 sites of the URLs it receives. If you enable this option the
5600 ICP replies from that peer will include the ICMP data (if available).
5601 Then, when choosing a parent cache, Squid will choose the parent with
5602 the minimal RTT to the origin server. When this happens, the
5603 hierarchy field of the access.log will be
5604 "CLOSEST_PARENT_MISS". This option is off by default.
5607 NAME: test_reachability
5611 LOC: Config.onoff.test_reachability
5613 When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
5614 instead of ICP_MISS if the target host is NOT in the ICMP
5615 database, or has a zero RTT.
5618 NAME: icp_query_timeout
5622 LOC: Config.Timeout.icp_query
5624 Normally Squid will automatically determine an optimal ICP
5625 query timeout value based on the round-trip-time of recent ICP
5626 queries. If you want to override the value determined by
5627 Squid, set this 'icp_query_timeout' to a non-zero value. This
5628 value is specified in MILLISECONDS, so, to use a 2-second
5629 timeout (the old default), you would write:
5631 icp_query_timeout 2000
5634 NAME: maximum_icp_query_timeout
5638 LOC: Config.Timeout.icp_query_max
5640 Normally the ICP query timeout is determined dynamically. But
5641 sometimes it can lead to very large values (say 5 seconds).
5642 Use this option to put an upper limit on the dynamic timeout
5643 value. Do NOT use this option to always use a fixed (instead
5644 of a dynamic) timeout value. To set a fixed timeout see the
5645 'icp_query_timeout' directive.
5648 NAME: minimum_icp_query_timeout
5652 LOC: Config.Timeout.icp_query_min
5654 Normally the ICP query timeout is determined dynamically. But
5655 sometimes it can lead to very small timeouts, even lower than
5656 the normal latency variance on your link due to traffic.
5657 Use this option to put an lower limit on the dynamic timeout
5658 value. Do NOT use this option to always use a fixed (instead
5659 of a dynamic) timeout value. To set a fixed timeout see the
5660 'icp_query_timeout' directive.
5663 NAME: background_ping_rate
5667 LOC: Config.backgroundPingRate
5669 Controls how often the ICP pings are sent to siblings that
5670 have background-ping set.
5674 MULTICAST ICP OPTIONS
5675 -----------------------------------------------------------------------------
5680 LOC: Config.mcast_group_list
5683 This tag specifies a list of multicast groups which your server
5684 should join to receive multicasted ICP queries.
5686 NOTE! Be very careful what you put here! Be sure you
5687 understand the difference between an ICP _query_ and an ICP
5688 _reply_. This option is to be set only if you want to RECEIVE
5689 multicast queries. Do NOT set this option to SEND multicast
5690 ICP (use cache_peer for that). ICP replies are always sent via
5691 unicast, so this option does not affect whether or not you will
5692 receive replies from multicast group members.
5694 You must be very careful to NOT use a multicast address which
5695 is already in use by another group of caches.
5697 If you are unsure about multicast, please read the Multicast
5698 chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
5700 Usage: mcast_groups 239.128.16.128 224.0.1.20
5702 By default, Squid doesn't listen on any multicast groups.
5705 NAME: mcast_miss_addr
5706 IFDEF: MULTICAST_MISS_STREAM
5708 LOC: Config.mcast_miss.addr
5711 If you enable this option, every "cache miss" URL will
5712 be sent out on the specified multicast address.
5714 Do not enable this option unless you are are absolutely
5715 certain you understand what you are doing.
5718 NAME: mcast_miss_ttl
5719 IFDEF: MULTICAST_MISS_STREAM
5721 LOC: Config.mcast_miss.ttl
5724 This is the time-to-live value for packets multicasted
5725 when multicasting off cache miss URLs is enabled. By
5726 default this is set to 'site scope', i.e. 16.
5729 NAME: mcast_miss_port
5730 IFDEF: MULTICAST_MISS_STREAM
5732 LOC: Config.mcast_miss.port
5735 This is the port number to be used in conjunction with
5739 NAME: mcast_miss_encode_key
5740 IFDEF: MULTICAST_MISS_STREAM
5742 LOC: Config.mcast_miss.encode_key
5743 DEFAULT: XXXXXXXXXXXXXXXX
5745 The URLs that are sent in the multicast miss stream are
5746 encrypted. This is the encryption key.
5749 NAME: mcast_icp_query_timeout
5753 LOC: Config.Timeout.mcast_icp_query
5755 For multicast peers, Squid regularly sends out ICP "probes" to
5756 count how many other peers are listening on the given multicast
5757 address. This value specifies how long Squid should wait to
5758 count all the replies. The default is 2000 msec, or 2
5763 INTERNAL ICON OPTIONS
5764 -----------------------------------------------------------------------------
5767 NAME: icon_directory
5769 LOC: Config.icons.directory
5770 DEFAULT: @DEFAULT_ICON_DIR@
5772 Where the icons are stored. These are normally kept in
5776 NAME: global_internal_static
5778 LOC: Config.onoff.global_internal_static
5781 This directive controls is Squid should intercept all requests for
5782 /squid-internal-static/ no matter which host the URL is requesting
5783 (default on setting), or if nothing special should be done for
5784 such URLs (off setting). The purpose of this directive is to make
5785 icons etc work better in complex cache hierarchies where it may
5786 not always be possible for all corners in the cache mesh to reach
5787 the server generating a directory listing.
5790 NAME: short_icon_urls
5792 LOC: Config.icons.use_short_names
5795 If this is enabled Squid will use short URLs for icons.
5796 If disabled it will revert to the old behavior of including
5797 it's own name and port in the URL.
5799 If you run a complex cache hierarchy with a mix of Squid and
5800 other proxies you may need to disable this directive.
5805 -----------------------------------------------------------------------------
5808 NAME: error_directory
5810 LOC: Config.errorDirectory
5813 If you wish to create your own versions of the default
5814 error files to customize them to suit your company copy
5815 the error/template files to another directory and point
5818 WARNING: This option will disable multi-language support
5819 on error pages if used.
5821 The squid developers are interested in making squid available in
5822 a wide variety of languages. If you are making translations for a
5823 language that Squid does not currently provide please consider
5824 contributing your translation back to the project.
5825 http://wiki.squid-cache.org/Translations
5827 The squid developers working on translations are happy to supply drop-in
5828 translated error files in exchange for any new language contributions.
5831 NAME: error_default_language
5832 IFDEF: USE_ERR_LOCALES
5834 LOC: Config.errorDefaultLanguage
5837 Set the default language which squid will send error pages in
5838 if no existing translation matches the clients language
5841 If unset (default) generic English will be used.
5843 The squid developers are interested in making squid available in
5844 a wide variety of languages. If you are interested in making
5845 translations for any language see the squid wiki for details.
5846 http://wiki.squid-cache.org/Translations
5849 NAME: error_log_languages
5850 IFDEF: USE_ERR_LOCALES
5852 LOC: Config.errorLogMissingLanguages
5855 Log to cache.log what languages users are attempting to
5856 auto-negotiate for translations.
5858 Successful negotiations are not logged. Only failures
5859 have meaning to indicate that Squid may need an upgrade
5860 of its error page translations.
5863 NAME: err_page_stylesheet
5865 LOC: Config.errorStylesheet
5866 DEFAULT: @DEFAULT_CONFIG_DIR@/errorpage.css
5868 CSS Stylesheet to pattern the display of Squid default error pages.
5870 For information on CSS see http://www.w3.org/Style/CSS/
5875 LOC: Config.errHtmlText
5878 HTML text to include in error messages. Make this a "mailto"
5879 URL to your admin address, or maybe just a link to your
5880 organizations Web page.
5882 To include this in your error messages, you must rewrite
5883 the error template files (found in the "errors" directory).
5884 Wherever you want the 'err_html_text' line to appear,
5885 insert a %L tag in the error template file.
5888 NAME: email_err_data
5891 LOC: Config.onoff.emailErrData
5894 If enabled, information about the occurred error will be
5895 included in the mailto links of the ERR pages (if %W is set)
5896 so that the email body contains the data.
5897 Syntax is <A HREF="mailto:%w%W">%w</A>
5902 LOC: Config.denyInfoList
5905 Usage: deny_info err_page_name acl
5906 or deny_info http://... acl
5907 or deny_info TCP_RESET acl
5909 This can be used to return a ERR_ page for requests which
5910 do not pass the 'http_access' rules. Squid remembers the last
5911 acl it evaluated in http_access, and if a 'deny_info' line exists
5912 for that ACL Squid returns a corresponding error page.
5914 The acl is typically the last acl on the http_access deny line which
5915 denied access. The exceptions to this rule are:
5916 - When Squid needs to request authentication credentials. It's then
5917 the first authentication related acl encountered
5918 - When none of the http_access lines matches. It's then the last
5919 acl processed on the last http_access line.
5920 - When the decision to deny access was made by an adaptation service,
5921 the acl name is the corresponding eCAP or ICAP service_name.
5923 NP: If providing your own custom error pages with error_directory
5924 you may also specify them by your custom file name:
5925 Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
5927 Alternatively you can tell Squid to reset the TCP connection
5928 by specifying TCP_RESET.
5930 Or you can specify an error URL or URL pattern. The browsers will
5931 get redirected (302) to the specified URL after formatting tags have
5935 %a - username (if available. Password NOT included)
5938 %E - Error description
5940 %H - Request domain name
5941 %i - Client IP Address
5943 %o - Message result from external ACL helper
5944 %p - Request Port number
5945 %P - Request Protocol name
5946 %R - Request URL path
5947 %T - Timestamp in RFC 1123 format
5948 %U - Full canonical URL from client
5949 (HTTPS URLs terminate with *)
5950 %u - Full canonical URL from client
5951 %w - Admin email from squid.conf
5952 %% - Literal percent (%) code
5957 OPTIONS INFLUENCING REQUEST FORWARDING
5958 -----------------------------------------------------------------------------
5961 NAME: nonhierarchical_direct
5963 LOC: Config.onoff.nonhierarchical_direct
5966 By default, Squid will send any non-hierarchical requests
5967 (matching hierarchy_stoplist or not cacheable request type) direct
5970 If you set this to off, Squid will prefer to send these
5971 requests to parents.
5973 Note that in most configurations, by turning this off you will only
5974 add latency to these request without any improvement in global hit
5977 If you are inside an firewall see never_direct instead of
5983 LOC: Config.onoff.prefer_direct
5986 Normally Squid tries to use parents for most requests. If you for some
5987 reason like it to first try going direct and only use a parent if
5988 going direct fails set this to on.
5990 By combining nonhierarchical_direct off and prefer_direct on you
5991 can set up Squid to use a parent as a backup path if going direct
5994 Note: If you want Squid to use parents for all requests see
5995 the never_direct directive. prefer_direct only modifies how Squid
5996 acts on cacheable requests.
6001 LOC: Config.accessList.AlwaysDirect
6004 Usage: always_direct allow|deny [!]aclname ...
6006 Here you can use ACL elements to specify requests which should
6007 ALWAYS be forwarded by Squid to the origin servers without using
6008 any peers. For example, to always directly forward requests for
6009 local servers ignoring any parents or siblings you may have use
6012 acl local-servers dstdomain my.domain.net
6013 always_direct allow local-servers
6015 To always forward FTP requests directly, use
6018 always_direct allow FTP
6020 NOTE: There is a similar, but opposite option named
6021 'never_direct'. You need to be aware that "always_direct deny
6022 foo" is NOT the same thing as "never_direct allow foo". You
6023 may need to use a deny rule to exclude a more-specific case of
6024 some other rule. Example:
6026 acl local-external dstdomain external.foo.net
6027 acl local-servers dstdomain .foo.net
6028 always_direct deny local-external
6029 always_direct allow local-servers
6031 NOTE: If your goal is to make the client forward the request
6032 directly to the origin server bypassing Squid then this needs
6033 to be done in the client configuration. Squid configuration
6034 can only tell Squid how Squid should fetch the object.
6036 NOTE: This directive is not related to caching. The replies
6037 is cached as usual even if you use always_direct. To not cache
6038 the replies see the 'cache' directive.
6040 This clause supports both fast and slow acl types.
6041 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6046 LOC: Config.accessList.NeverDirect
6049 Usage: never_direct allow|deny [!]aclname ...
6051 never_direct is the opposite of always_direct. Please read
6052 the description for always_direct if you have not already.
6054 With 'never_direct' you can use ACL elements to specify
6055 requests which should NEVER be forwarded directly to origin
6056 servers. For example, to force the use of a proxy for all
6057 requests, except those in your local domain use something like:
6059 acl local-servers dstdomain .foo.net
6060 never_direct deny local-servers
6061 never_direct allow all
6063 or if Squid is inside a firewall and there are local intranet
6064 servers inside the firewall use something like:
6066 acl local-intranet dstdomain .foo.net
6067 acl local-external dstdomain external.foo.net
6068 always_direct deny local-external
6069 always_direct allow local-intranet
6070 never_direct allow all
6072 This clause supports both fast and slow acl types.
6073 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6077 ADVANCED NETWORKING OPTIONS
6078 -----------------------------------------------------------------------------
6081 NAME: incoming_icp_average
6084 LOC: Config.comm_incoming.icp_average
6087 NAME: incoming_http_average
6090 LOC: Config.comm_incoming.http_average
6093 NAME: incoming_dns_average
6096 LOC: Config.comm_incoming.dns_average
6099 NAME: min_icp_poll_cnt
6102 LOC: Config.comm_incoming.icp_min_poll
6105 NAME: min_dns_poll_cnt
6108 LOC: Config.comm_incoming.dns_min_poll
6111 NAME: min_http_poll_cnt
6114 LOC: Config.comm_incoming.http_min_poll
6116 Heavy voodoo here. I can't even believe you are reading this.
6117 Are you crazy? Don't even think about adjusting these unless
6118 you understand the algorithms in comm_select.c first!
6124 LOC: Config.accept_filter
6128 The name of an accept(2) filter to install on Squid's
6129 listen socket(s). This feature is perhaps specific to
6130 FreeBSD and requires support in the kernel.
6132 The 'httpready' filter delays delivering new connections
6133 to Squid until a full HTTP request has been received.
6134 See the accf_http(9) man page for details.
6136 The 'dataready' filter delays delivering new connections
6137 to Squid until there is some data to process.
6138 See the accf_dataready(9) man page for details.
6142 The 'data' filter delays delivering of new connections
6143 to Squid until there is some data to process by TCP_ACCEPT_DEFER.
6144 You may optionally specify a number of seconds to wait by
6145 'data=N' where N is the number of seconds. Defaults to 30
6146 if not specified. See the tcp(7) man page for details.
6149 accept_filter httpready
6154 NAME: client_ip_max_connections
6156 LOC: Config.client_ip_max_connections
6159 Set an absolute limit on the number of connections a single
6160 client IP can use. Any more than this and Squid will begin to drop
6161 new connections from the client until it closes some links.
6163 Note that this is a global limit. It affects all HTTP, HTCP, Gopher and FTP
6164 connections from the client. For finer control use the ACL access controls.
6166 Requires client_db to be enabled (the default).
6168 WARNING: This may noticably slow down traffic received via external proxies
6169 or NAT devices and cause them to rebound error messages back to their clients.
6172 NAME: tcp_recv_bufsize
6176 LOC: Config.tcpRcvBufsz
6178 Size of receive buffer to set for TCP sockets. Probably just
6179 as easy to change your kernel's default. Set to zero to use
6180 the default buffer size.
6185 -----------------------------------------------------------------------------
6192 LOC: Adaptation::Icap::TheConfig.onoff
6195 If you want to enable the ICAP module support, set this to on.
6198 NAME: icap_connect_timeout
6201 LOC: Adaptation::Icap::TheConfig.connect_timeout_raw
6204 This parameter specifies how long to wait for the TCP connect to
6205 the requested ICAP server to complete before giving up and either
6206 terminating the HTTP transaction or bypassing the failure.
6208 The default for optional services is peer_connect_timeout.
6209 The default for essential services is connect_timeout.
6210 If this option is explicitly set, its value applies to all services.
6213 NAME: icap_io_timeout
6217 LOC: Adaptation::Icap::TheConfig.io_timeout_raw
6220 This parameter specifies how long to wait for an I/O activity on
6221 an established, active ICAP connection before giving up and
6222 either terminating the HTTP transaction or bypassing the
6225 The default is read_timeout.
6228 NAME: icap_service_failure_limit
6229 COMMENT: limit [in memory-depth time-units]
6230 TYPE: icap_service_failure_limit
6232 LOC: Adaptation::Icap::TheConfig
6235 The limit specifies the number of failures that Squid tolerates
6236 when establishing a new TCP connection with an ICAP service. If
6237 the number of failures exceeds the limit, the ICAP service is
6238 not used for new ICAP requests until it is time to refresh its
6241 A negative value disables the limit. Without the limit, an ICAP
6242 service will not be considered down due to connectivity failures
6243 between ICAP OPTIONS requests.
6245 Squid forgets ICAP service failures older than the specified
6246 value of memory-depth. The memory fading algorithm
6247 is approximate because Squid does not remember individual
6248 errors but groups them instead, splitting the option
6249 value into ten time slots of equal length.
6251 When memory-depth is 0 and by default this option has no
6252 effect on service failure expiration.
6254 Squid always forgets failures when updating service settings
6255 using an ICAP OPTIONS transaction, regardless of this option
6259 # suspend service usage after 10 failures in 5 seconds:
6260 icap_service_failure_limit 10 in 5 seconds
6263 NAME: icap_service_revival_delay
6266 LOC: Adaptation::Icap::TheConfig.service_revival_delay
6269 The delay specifies the number of seconds to wait after an ICAP
6270 OPTIONS request failure before requesting the options again. The
6271 failed ICAP service is considered "down" until fresh OPTIONS are
6274 The actual delay cannot be smaller than the hardcoded minimum
6275 delay of 30 seconds.
6278 NAME: icap_preview_enable
6282 LOC: Adaptation::Icap::TheConfig.preview_enable
6285 The ICAP Preview feature allows the ICAP server to handle the
6286 HTTP message by looking only at the beginning of the message body
6287 or even without receiving the body at all. In some environments,
6288 previews greatly speedup ICAP processing.
6290 During an ICAP OPTIONS transaction, the server may tell Squid what
6291 HTTP messages should be previewed and how big the preview should be.
6292 Squid will not use Preview if the server did not request one.
6294 To disable ICAP Preview for all ICAP services, regardless of
6295 individual ICAP server OPTIONS responses, set this option to "off".
6297 icap_preview_enable off
6300 NAME: icap_preview_size
6303 LOC: Adaptation::Icap::TheConfig.preview_size
6306 The default size of preview data to be sent to the ICAP server.
6307 -1 means no preview. This value might be overwritten on a per server
6308 basis by OPTIONS requests.
6311 NAME: icap_206_enable
6315 LOC: Adaptation::Icap::TheConfig.allow206_enable
6318 206 (Partial Content) responses is an ICAP extension that allows the
6319 ICAP agents to optionally combine adapted and original HTTP message
6320 content. The decision to combine is postponed until the end of the
6321 ICAP response. Squid supports Partial Content extension by default.
6323 Activation of the Partial Content extension is negotiated with each
6324 ICAP service during OPTIONS exchange. Most ICAP servers should handle
6325 negotation correctly even if they do not support the extension, but
6326 some might fail. To disable Partial Content support for all ICAP
6327 services and to avoid any negotiation, set this option to "off".
6333 NAME: icap_default_options_ttl
6336 LOC: Adaptation::Icap::TheConfig.default_options_ttl
6339 The default TTL value for ICAP OPTIONS responses that don't have
6340 an Options-TTL header.
6343 NAME: icap_persistent_connections
6347 LOC: Adaptation::Icap::TheConfig.reuse_connections
6350 Whether or not Squid should use persistent connections to
6354 NAME: adaptation_send_client_ip icap_send_client_ip
6356 IFDEF: USE_ADAPTATION
6358 LOC: Adaptation::Config::send_client_ip
6361 This adds the header "X-Client-IP" to ICAP requests.
6364 NAME: adaptation_send_username icap_send_client_username
6366 IFDEF: USE_ADAPTATION
6368 LOC: Adaptation::Config::send_username
6371 This sends authenticated HTTP client username (if available) to
6372 the adaptation service.
6374 For ICAP, the username value is encoded based on the
6375 icap_client_username_encode option and is sent using the header
6376 specified by the icap_client_username_header option.
6379 NAME: icap_client_username_header
6382 LOC: Adaptation::Icap::TheConfig.client_username_header
6383 DEFAULT: X-Client-Username
6385 ICAP request header name to use for send_username.
6388 NAME: icap_client_username_encode
6392 LOC: Adaptation::Icap::TheConfig.client_username_encode
6395 Whether to base64 encode the authenticated client username.
6399 TYPE: icap_service_type
6401 LOC: Adaptation::Icap::TheConfig
6404 Defines a single ICAP service using the following format:
6406 icap_service service_name vectoring_point [options] service_url
6409 an opaque identifier which must be unique in squid.conf
6411 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
6412 This specifies at which point of transaction processing the
6413 ICAP service should be activated. *_postcache vectoring points
6414 are not yet supported.
6416 service_url: icap://servername:port/servicepath
6417 ICAP server and service location.
6419 ICAP does not allow a single service to handle both REQMOD and RESPMOD
6420 transactions. Squid does not enforce that requirement. You can specify
6421 services with the same service_url and different vectoring_points. You
6422 can even specify multiple identical services as long as their
6423 service_names differ.
6426 Service options are separated by white space. ICAP services support
6427 the following name=value options:
6430 If set to 'on' or '1', the ICAP service is treated as
6431 optional. If the service cannot be reached or malfunctions,
6432 Squid will try to ignore any errors and process the message as
6433 if the service was not enabled. No all ICAP errors can be
6434 bypassed. If set to 0, the ICAP service is treated as
6435 essential and all ICAP errors will result in an error page
6436 returned to the HTTP client.
6438 Bypass is off by default: services are treated as essential.
6441 If set to 'on' or '1', the ICAP service is allowed to
6442 dynamically change the current message adaptation plan by
6443 returning a chain of services to be used next. The services
6444 are specified using the X-Next-Services ICAP response header
6445 value, formatted as a comma-separated list of service names.
6446 Each named service should be configured in squid.conf and
6447 should have the same method and vectoring point as the current
6448 ICAP transaction. Services violating these rules are ignored.
6449 An empty X-Next-Services value results in an empty plan which
6450 ends the current adaptation.
6452 Routing is not allowed by default: the ICAP X-Next-Services
6453 response header is ignored.
6456 Only has effect on split-stack systems. The default on those systems
6457 is to use IPv4-only connections. When set to 'on' this option will
6458 make Squid use IPv6-only connections to contact this ICAP service.
6460 Older icap_service format without optional named parameters is
6461 deprecated but supported for backward compatibility.
6464 icap_service svcBlocker reqmod_precache bypass=0 icap://icap1.mydomain.net:1344/reqmod
6465 icap_service svcLogger reqmod_precache routing=on icap://icap2.mydomain.net:1344/respmod
6469 TYPE: icap_class_type
6474 This deprecated option was documented to define an ICAP service
6475 chain, even though it actually defined a set of similar, redundant
6476 services, and the chains were not supported.
6478 To define a set of redundant services, please use the
6479 adaptation_service_set directive. For service chains, use
6480 adaptation_service_chain.
6484 TYPE: icap_access_type
6489 This option is deprecated. Please use adaptation_access, which
6490 has the same ICAP functionality, but comes with better
6491 documentation, and eCAP support.
6496 -----------------------------------------------------------------------------
6503 LOC: Adaptation::Ecap::TheConfig.onoff
6506 Controls whether eCAP support is enabled.
6510 TYPE: ecap_service_type
6512 LOC: Adaptation::Ecap::TheConfig
6515 Defines a single eCAP service
6517 ecap_service servicename vectoring_point bypass service_url
6519 vectoring_point = reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
6520 This specifies at which point of transaction processing the
6521 eCAP service should be activated. *_postcache vectoring points
6522 are not yet supported.
6524 If set to 1, the eCAP service is treated as optional. If the
6525 service cannot be reached or malfunctions, Squid will try to
6526 ignore any errors and process the message as if the service
6527 was not enabled. No all eCAP errors can be bypassed.
6528 If set to 0, the eCAP service is treated as essential and all
6529 eCAP errors will result in an error page returned to the
6531 service_url = ecap://vendor/service_name?custom&cgi=style¶meters=optional
6534 ecap_service service_1 reqmod_precache 0 ecap://filters-R-us/leakDetector?on_error=block
6535 ecap_service service_2 respmod_precache 1 icap://filters-R-us/virusFilter?config=/etc/vf.cfg
6538 NAME: loadable_modules
6540 IFDEF: USE_LOADABLE_MODULES
6541 LOC: Config.loadable_module_names
6544 Instructs Squid to load the specified dynamic module(s) or activate
6545 preloaded module(s).
6547 loadable_modules @DEFAULT_PREFIX@/lib/MinimalAdapter.so
6551 MESSAGE ADAPTATION OPTIONS
6552 -----------------------------------------------------------------------------
6555 NAME: adaptation_service_set
6556 TYPE: adaptation_service_set_type
6557 IFDEF: USE_ADAPTATION
6562 Configures an ordered set of similar, redundant services. This is
6563 useful when hot standby or backup adaptation servers are available.
6565 adaptation_service_set set_name service_name1 service_name2 ...
6567 The named services are used in the set declaration order. The first
6568 applicable adaptation service from the set is used first. The next
6569 applicable service is tried if and only if the transaction with the
6570 previous service fails and the message waiting to be adapted is still
6573 When adaptation starts, broken services are ignored as if they were
6574 not a part of the set. A broken service is a down optional service.
6576 The services in a set must be attached to the same vectoring point
6577 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
6579 If all services in a set are optional then adaptation failures are
6580 bypassable. If all services in the set are essential, then a
6581 transaction failure with one service may still be retried using
6582 another service from the set, but when all services fail, the master
6583 transaction fails as well.
6585 A set may contain a mix of optional and essential services, but that
6586 is likely to lead to surprising results because broken services become
6587 ignored (see above), making previously bypassable failures fatal.
6588 Technically, it is the bypassability of the last failed service that
6591 See also: adaptation_access adaptation_service_chain
6594 adaptation_service_set svcBlocker urlFilterPrimary urlFilterBackup
6595 adaptation service_set svcLogger loggerLocal loggerRemote
6598 NAME: adaptation_service_chain
6599 TYPE: adaptation_service_chain_type
6600 IFDEF: USE_ADAPTATION
6605 Configures a list of complementary services that will be applied
6606 one-by-one, forming an adaptation chain or pipeline. This is useful
6607 when Squid must perform different adaptations on the same message.
6609 adaptation_service_chain chain_name service_name1 svc_name2 ...
6611 The named services are used in the chain declaration order. The first
6612 applicable adaptation service from the chain is used first. The next
6613 applicable service is applied to the successful adaptation results of
6614 the previous service in the chain.
6616 When adaptation starts, broken services are ignored as if they were
6617 not a part of the chain. A broken service is a down optional service.
6619 Request satisfaction terminates the adaptation chain because Squid
6620 does not currently allow declaration of RESPMOD services at the
6621 "reqmod_precache" vectoring point (see icap_service or ecap_service).
6623 The services in a chain must be attached to the same vectoring point
6624 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
6626 A chain may contain a mix of optional and essential services. If an
6627 essential adaptation fails (or the failure cannot be bypassed for
6628 other reasons), the master transaction fails. Otherwise, the failure
6629 is bypassed as if the failed adaptation service was not in the chain.
6631 See also: adaptation_access adaptation_service_set
6634 adaptation_service_chain svcRequest requestLogger urlFilter leakDetector
6637 NAME: adaptation_access
6638 TYPE: adaptation_access_type
6639 IFDEF: USE_ADAPTATION
6643 Sends an HTTP transaction to an ICAP or eCAP adaptation service.
6645 adaptation_access service_name allow|deny [!]aclname...
6646 adaptation_access set_name allow|deny [!]aclname...
6648 At each supported vectoring point, the adaptation_access
6649 statements are processed in the order they appear in this
6650 configuration file. Statements pointing to the following services
6651 are ignored (i.e., skipped without checking their ACL):
6653 - services serving different vectoring points
6654 - "broken-but-bypassable" services
6655 - "up" services configured to ignore such transactions
6656 (e.g., based on the ICAP Transfer-Ignore header).
6658 When a set_name is used, all services in the set are checked
6659 using the same rules, to find the first applicable one. See
6660 adaptation_service_set for details.
6662 If an access list is checked and there is a match, the
6663 processing stops: For an "allow" rule, the corresponding
6664 adaptation service is used for the transaction. For a "deny"
6665 rule, no adaptation service is activated.
6667 It is currently not possible to apply more than one adaptation
6668 service at the same vectoring point to the same HTTP transaction.
6670 See also: icap_service and ecap_service
6673 adaptation_access service_1 allow all
6676 NAME: adaptation_service_iteration_limit
6678 IFDEF: USE_ADAPTATION
6679 LOC: Adaptation::Config::service_iteration_limit
6682 Limits the number of iterations allowed when applying adaptation
6683 services to a message. If your longest adaptation set or chain
6684 may have more than 16 services, increase the limit beyond its
6685 default value of 16. If detecting infinite iteration loops sooner
6686 is critical, make the iteration limit match the actual number
6687 of services in your longest adaptation set or chain.
6689 Infinite adaptation loops are most likely with routing services.
6691 See also: icap_service routing=1
6694 NAME: adaptation_masterx_shared_names
6696 IFDEF: USE_ADAPTATION
6697 LOC: Adaptation::Config::masterx_shared_name
6700 For each master transaction (i.e., the HTTP request and response
6701 sequence, including all related ICAP and eCAP exchanges), Squid
6702 maintains a table of metadata. The table entries are (name, value)
6703 pairs shared among eCAP and ICAP exchanges. The table is destroyed
6704 with the master transaction.
6706 This option specifies the table entry names that Squid must accept
6707 from and forward to the adaptation transactions.
6709 An ICAP REQMOD or RESPMOD transaction may set an entry in the
6710 shared table by returning an ICAP header field with a name
6711 specified in adaptation_masterx_shared_names. Squid will store
6712 and forward that ICAP header field to subsequent ICAP
6713 transactions within the same master transaction scope.
6715 Only one shared entry name is supported at this time.
6718 # share authentication information among ICAP services
6719 adaptation_masterx_shared_names X-Subscriber-ID
6725 LOC: Adaptation::Icap::TheConfig.repeat
6726 DEFAULT_IF_NONE: deny all
6728 This ACL determines which retriable ICAP transactions are
6729 retried. Transactions that received a complete ICAP response
6730 and did not have to consume or produce HTTP bodies to receive
6731 that response are usually retriable.
6733 icap_retry allow|deny [!]aclname ...
6735 Squid automatically retries some ICAP I/O timeouts and errors
6736 due to persistent connection race conditions.
6738 See also: icap_retry_limit
6741 NAME: icap_retry_limit
6744 LOC: Adaptation::Icap::TheConfig.repeat_limit
6747 Limits the number of retries allowed. When set to zero (default),
6748 no retries are allowed.
6750 Communication errors due to persistent connection race
6751 conditions are unavoidable, automatically retried, and do not
6752 count against this limit.
6754 See also: icap_retry
6760 -----------------------------------------------------------------------------
6763 NAME: check_hostnames
6766 LOC: Config.onoff.check_hostnames
6768 For security and stability reasons Squid can check
6769 hostnames for Internet standard RFC compliance. If you want
6770 Squid to perform these checks turn this directive on.
6773 NAME: allow_underscore
6776 LOC: Config.onoff.allow_underscore
6778 Underscore characters is not strictly allowed in Internet hostnames
6779 but nevertheless used by many sites. Set this to off if you want
6780 Squid to be strict about the standard.
6781 This check is performed only when check_hostnames is set to on.
6784 NAME: cache_dns_program
6786 IFDEF: USE_DNSSERVERS
6787 DEFAULT: @DEFAULT_DNSSERVER@
6788 LOC: Config.Program.dnsserver
6790 Specify the location of the executable for dnslookup process.
6794 TYPE: HelperChildConfig
6795 IFDEF: USE_DNSSERVERS
6796 DEFAULT: 32 startup=1 idle=1
6797 LOC: Config.dnsChildren
6799 The maximum number of processes spawn to service DNS name lookups.
6800 If you limit it too few Squid will have to wait for them to process
6801 a backlog of requests, slowing it down. If you allow too many they
6802 will use RAM and other system resources noticably.
6803 The maximum this may be safely set to is 32.
6805 The startup= and idle= options allow some measure of skew in your
6810 Sets a minimum of how many processes are to be spawned when Squid
6811 starts or reconfigures. When set to zero the first request will
6812 cause spawning of the first child process to handle it.
6814 Starting too few will cause an initial slowdown in traffic as Squid
6815 attempts to simultaneously spawn enough processes to cope.
6819 Sets a minimum of how many processes Squid is to try and keep available
6820 at all times. When traffic begins to rise above what the existing
6821 processes can handle this many more will be spawned up to the maximum
6822 configured. A minimum setting of 1 is required.
6825 NAME: dns_retransmit_interval
6828 LOC: Config.Timeout.idns_retransmit
6829 IFDEF: !USE_DNSSERVERS
6831 Initial retransmit interval for DNS queries. The interval is
6832 doubled each time all configured DNS servers have been tried.
6838 LOC: Config.Timeout.idns_query
6839 IFDEF: !USE_DNSSERVERS
6841 DNS Query timeout. If no response is received to a DNS query
6842 within this time all DNS servers for the queried domain
6843 are assumed to be unavailable.
6846 NAME: dns_packet_max
6849 LOC: Config.dns.packet_max
6850 IFDEF: !USE_DNSSERVERS
6852 Maximum number of bytes packet size to advertise via EDNS.
6853 Set to "none" to disable EDNS large packet support.
6855 For legacy reasons DNS UDP replies will default to 512 bytes which
6856 is too small for many responses. EDNS provides a means for Squid to
6857 negotiate receiving larger responses back immediately without having
6858 to failover with repeat requests. Responses larger than this limit
6859 will retain the old behaviour of failover to TCP DNS.
6861 Squid has no real fixed limit internally, but allowing packet sizes
6862 over 1500 bytes requires network jumbogram support and is usually not
6865 WARNING: The RFC also indicates that some older resolvers will reply
6866 with failure of the whole request if the extension is added. Some
6867 resolvers have already been identified which will reply with mangled
6868 EDNS response on occasion. Usually in response to many-KB jumbogram
6869 sizes being advertised by Squid.
6870 Squid will currently treat these both as an unable-to-resolve domain
6871 even if it would be resolvable without EDNS.
6878 LOC: Config.onoff.res_defnames
6880 Normally the RES_DEFNAMES resolver option is disabled
6881 (see res_init(3)). This prevents caches in a hierarchy
6882 from interpreting single-component hostnames locally. To allow
6883 Squid to handle single-component names, enable this option.
6886 NAME: dns_nameservers
6889 LOC: Config.dns_nameservers
6891 Use this if you want to specify a list of DNS name servers
6892 (IP addresses) to use instead of those given in your
6893 /etc/resolv.conf file.
6894 On Windows platforms, if no value is specified here or in
6895 the /etc/resolv.conf file, the list of DNS name servers are
6896 taken from the Windows registry, both static and dynamic DHCP
6897 configurations are supported.
6899 Example: dns_nameservers 10.0.0.1 192.172.0.4
6904 DEFAULT: @DEFAULT_HOSTS@
6905 LOC: Config.etcHostsPath
6907 Location of the host-local IP name-address associations
6908 database. Most Operating Systems have such a file on different
6910 - Un*X & Linux: /etc/hosts
6911 - Windows NT/2000: %SystemRoot%\system32\drivers\etc\hosts
6912 (%SystemRoot% value install default is c:\winnt)
6913 - Windows XP/2003: %SystemRoot%\system32\drivers\etc\hosts
6914 (%SystemRoot% value install default is c:\windows)
6915 - Windows 9x/Me: %windir%\hosts
6916 (%windir% value is usually c:\windows)
6917 - Cygwin: /etc/hosts
6919 The file contains newline-separated definitions, in the
6920 form ip_address_in_dotted_form name [name ...] names are
6921 whitespace-separated. Lines beginning with an hash (#)
6922 character are comments.
6924 The file is checked at startup and upon configuration.
6925 If set to 'none', it won't be checked.
6926 If append_domain is used, that domain will be added to
6927 domain-local (i.e. not containing any dot character) host
6933 LOC: Config.appendDomain
6936 Appends local domain name to hostnames without any dots in
6937 them. append_domain must begin with a period.
6939 Be warned there are now Internet names with no dots in
6940 them using only top-domain names, so setting this may
6941 cause some Internet sites to become unavailable.
6944 append_domain .yourdomain.com
6947 NAME: ignore_unknown_nameservers
6949 LOC: Config.onoff.ignore_unknown_nameservers
6952 By default Squid checks that DNS responses are received
6953 from the same IP addresses they are sent to. If they
6954 don't match, Squid ignores the response and writes a warning
6955 message to cache.log. You can allow responses from unknown
6956 nameservers by setting this option to 'off'.
6959 NAME: dns_v4_fallback
6962 LOC: Config.onoff.dns_require_A
6964 Standard practice with DNS is to lookup either A or AAAA records
6965 and use the results if it succeeds. Only looking up the other if
6966 the first attempt fails or otherwise produces no results.
6968 That policy however will cause squid to produce error pages for some
6969 servers that advertise AAAA but are unreachable over IPv6.
6971 If this is ON squid will always lookup both AAAA and A, using both.
6972 If this is OFF squid will lookup AAAA and only try A if none found.
6974 WARNING: There are some possibly unwanted side-effects with this on:
6975 *) Doubles the load placed by squid on the DNS network.
6976 *) May negatively impact connection delay times.
6980 COMMENT: (number of entries)
6983 LOC: Config.ipcache.size
6990 LOC: Config.ipcache.low
6997 LOC: Config.ipcache.high
6999 The size, low-, and high-water marks for the IP cache.
7002 NAME: fqdncache_size
7003 COMMENT: (number of entries)
7006 LOC: Config.fqdncache.size
7008 Maximum number of FQDN cache entries.
7013 -----------------------------------------------------------------------------
7020 LOC: Config.onoff.mem_pools
7022 If set, Squid will keep pools of allocated (but unused) memory
7023 available for future use. If memory is a premium on your
7024 system and you believe your malloc library outperforms Squid
7025 routines, disable this.
7028 NAME: memory_pools_limit
7032 LOC: Config.MemPools.limit
7034 Used only with memory_pools on:
7035 memory_pools_limit 50 MB
7037 If set to a non-zero value, Squid will keep at most the specified
7038 limit of allocated (but unused) memory in memory pools. All free()
7039 requests that exceed this limit will be handled by your malloc
7040 library. Squid does not pre-allocate any memory, just safe-keeps
7041 objects that otherwise would be free()d. Thus, it is safe to set
7042 memory_pools_limit to a reasonably high value even if your
7043 configuration will use less memory.
7045 If set to none, Squid will keep all memory it can. That is, there
7046 will be no limit on the total amount of memory used for safe-keeping.
7048 To disable memory allocation optimization, do not set
7049 memory_pools_limit to 0 or none. Set memory_pools to "off" instead.
7051 An overhead for maintaining memory pools is not taken into account
7052 when the limit is checked. This overhead is close to four bytes per
7053 object kept. However, pools may actually _save_ memory because of
7054 reduced memory thrashing in your malloc library.
7058 COMMENT: on|off|transparent|truncate|delete
7061 LOC: opt_forwarded_for
7063 If set to "on", Squid will append your client's IP address
7064 in the HTTP requests it forwards. By default it looks like:
7066 X-Forwarded-For: 192.1.2.3
7068 If set to "off", it will appear as
7070 X-Forwarded-For: unknown
7072 If set to "transparent", Squid will not alter the
7073 X-Forwarded-For header in any way.
7075 If set to "delete", Squid will delete the entire
7076 X-Forwarded-For header.
7078 If set to "truncate", Squid will remove all existing
7079 X-Forwarded-For entries, and place itself as the sole entry.
7082 NAME: cachemgr_passwd
7083 TYPE: cachemgrpasswd
7085 LOC: Config.passwd_list
7087 Specify passwords for cachemgr operations.
7089 Usage: cachemgr_passwd password action action ...
7091 Some valid actions are (see cache manager menu for a full list):
7131 * Indicates actions which will not be performed without a
7132 valid password, others can be performed if not listed here.
7134 To disable an action, set the password to "disable".
7135 To allow performing an action without a password, set the
7138 Use the keyword "all" to set the same password for all actions.
7141 cachemgr_passwd secret shutdown
7142 cachemgr_passwd lesssssssecret info stats/objects
7143 cachemgr_passwd disable all
7150 LOC: Config.onoff.client_db
7152 If you want to disable collecting per-client statistics,
7153 turn off client_db here.
7156 NAME: refresh_all_ims
7160 LOC: Config.onoff.refresh_all_ims
7162 When you enable this option, squid will always check
7163 the origin server for an update when a client sends an
7164 If-Modified-Since request. Many browsers use IMS
7165 requests when the user requests a reload, and this
7166 ensures those clients receive the latest version.
7168 By default (off), squid may return a Not Modified response
7169 based on the age of the cached version.
7172 NAME: reload_into_ims
7173 IFDEF: USE_HTTP_VIOLATIONS
7177 LOC: Config.onoff.reload_into_ims
7179 When you enable this option, client no-cache or ``reload''
7180 requests will be changed to If-Modified-Since requests.
7181 Doing this VIOLATES the HTTP standard. Enabling this
7182 feature could make you liable for problems which it
7185 see also refresh_pattern for a more selective approach.
7188 NAME: maximum_single_addr_tries
7190 LOC: Config.retry.maxtries
7193 This sets the maximum number of connection attempts for a
7194 host that only has one address (for multiple-address hosts,
7195 each address is tried once).
7197 The default value is one attempt, the (not recommended)
7198 maximum is 255 tries. A warning message will be generated
7199 if it is set to a value greater than ten.
7201 Note: This is in addition to the request re-forwarding which
7202 takes place if Squid fails to get a satisfying response.
7205 NAME: retry_on_error
7207 LOC: Config.retry.onerror
7210 If set to on Squid will automatically retry requests when
7211 receiving an error response. This is mainly useful if you
7212 are in a complex cache hierarchy to work around access
7216 NAME: as_whois_server
7218 LOC: Config.as_whois_server
7219 DEFAULT: whois.ra.net
7221 WHOIS server to query for AS numbers. NOTE: AS numbers are
7222 queried only when Squid starts up, not for every request.
7227 LOC: Config.onoff.offline
7230 Enable this option and Squid will never try to validate cached
7234 NAME: uri_whitespace
7235 TYPE: uri_whitespace
7236 LOC: Config.uri_whitespace
7239 What to do with requests that have whitespace characters in the
7242 strip: The whitespace characters are stripped out of the URL.
7243 This is the behavior recommended by RFC2396.
7244 deny: The request is denied. The user receives an "Invalid
7246 allow: The request is allowed and the URI is not changed. The
7247 whitespace characters remain in the URI. Note the
7248 whitespace is passed to redirector processes if they
7250 encode: The request is allowed and the whitespace characters are
7251 encoded according to RFC1738. This could be considered
7252 a violation of the HTTP/1.1
7253 RFC because proxies are not allowed to rewrite URI's.
7254 chop: The request is allowed and the URI is chopped at the
7255 first whitespace. This might also be considered a
7261 LOC: Config.chroot_dir
7264 Specifies a directory where Squid should do a chroot() while
7265 initializing. This also causes Squid to fully drop root
7266 privileges after initializing. This means, for example, if you
7267 use a HTTP port less than 1024 and try to reconfigure, you may
7268 get an error saying that Squid can not open the port.
7271 NAME: balance_on_multiple_ip
7273 LOC: Config.onoff.balance_on_multiple_ip
7276 Modern IP resolvers in squid sort lookup results by preferred access.
7277 By default squid will use these IP in order and only rotates to
7278 the next listed when the most preffered fails.
7280 Some load balancing servers based on round robin DNS have been
7281 found not to preserve user session state across requests
7282 to different IP addresses.
7284 Enabling this directive Squid rotates IP's per request.
7287 NAME: pipeline_prefetch
7289 LOC: Config.onoff.pipeline_prefetch
7292 To boost the performance of pipelined requests to closer
7293 match that of a non-proxied environment Squid can try to fetch
7294 up to two requests in parallel from a pipeline.
7296 Defaults to off for bandwidth management and access logging
7300 NAME: high_response_time_warning
7303 LOC: Config.warnings.high_rptm
7306 If the one-minute median response time exceeds this value,
7307 Squid prints a WARNING with debug level 0 to get the
7308 administrators attention. The value is in milliseconds.
7311 NAME: high_page_fault_warning
7313 LOC: Config.warnings.high_pf
7316 If the one-minute average page fault rate exceeds this
7317 value, Squid prints a WARNING with debug level 0 to get
7318 the administrators attention. The value is in page faults
7322 NAME: high_memory_warning
7324 LOC: Config.warnings.high_memory
7327 If the memory usage (as determined by mallinfo) exceeds
7328 this amount, Squid prints a WARNING with debug level 0 to get
7329 the administrators attention.
7332 NAME: sleep_after_fork
7333 COMMENT: (microseconds)
7335 LOC: Config.sleep_after_fork
7338 When this is set to a non-zero value, the main Squid process
7339 sleeps the specified number of microseconds after a fork()
7340 system call. This sleep may help the situation where your
7341 system reports fork() failures due to lack of (virtual)
7342 memory. Note, however, if you have a lot of child
7343 processes, these sleep delays will add up and your
7344 Squid will not service requests for some amount of time
7345 until all the child processes have been started.
7346 On Windows value less then 1000 (1 milliseconds) are
7350 NAME: windows_ipaddrchangemonitor
7351 IFDEF: _SQUID_MSWIN_
7355 LOC: Config.onoff.WIN32_IpAddrChangeMonitor
7357 On Windows Squid by default will monitor IP address changes and will
7358 reconfigure itself after any detected event. This is very useful for
7359 proxies connected to internet with dial-up interfaces.
7360 In some cases (a Proxy server acting as VPN gateway is one) it could be
7361 desiderable to disable this behaviour setting this to 'off'.
7362 Note: after changing this, Squid service must be restarted.
7367 IFDEF: USE_SQUID_EUI
7369 LOC: Eui::TheConfig.euiLookup
7371 Whether to lookup the EUI or MAC address of a connected client.
7374 NAME: max_filedescriptors max_filedesc
7377 LOC: Config.max_filedescriptors
7379 The maximum number of filedescriptors supported.
7381 The default "0" means Squid inherits the current ulimit setting.
7383 Note: Changing this requires a restart of Squid. Also
7384 not all comm loops supports large values.
7392 Number of main Squid processes or "workers" to fork and maintain.
7393 0: "no daemon" mode, like running "squid -N ..."
7394 1: "no SMP" mode, start one main Squid process daemon (default)
7395 N: start N main Squid process daemons (i.e., SMP mode)
7397 In SMP mode, each worker does nearly all what a single Squid daemon
7398 does (e.g., listen on http_port and forward HTTP requests).
7401 NAME: cpu_affinity_map
7402 TYPE: CpuAffinityMap
7403 LOC: Config.cpuAffinityMap
7406 Usage: cpu_affinity_map process_numbers=P1,P2,... cores=C1,C2,...
7408 Sets 1:1 mapping between Squid processes and CPU cores. For example,
7410 cpu_affinity_map process_numbers=1,2,3,4 cores=1,3,5,7
7412 affects processes 1 through 4 only and places them on the first
7413 four even cores, starting with core #1.
7415 CPU cores are numbered starting from 1. Requires support for
7416 sched_getaffinity(2) and sched_setaffinity(2) system calls.
7418 Multiple cpu_affinity_map options are merged.
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