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 IP multicast TTL to use when sending an ICP
2177 queries to this address.
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 max-size=n, refers to the max object size this storedir supports.
2718 It is used to initially choose the storedir to dump the object.
2719 Note: To make optimal use of the max-size limits you should order
2720 the cache_dir lines with the smallest max-size value first and the
2721 ones with no max-size specification last.
2723 Note for coss, max-size must be less than COSS_MEMBUF_SZ,
2724 which can be changed with the --with-coss-membuf-size=N configure
2728 # Uncomment and adjust the following to add a disk cache directory.
2729 #cache_dir ufs @DEFAULT_SWAP_DIR@ 100 16 256
2733 NAME: store_dir_select_algorithm
2735 LOC: Config.store_dir_select_algorithm
2738 Set this to 'round-robin' as an alternative.
2741 NAME: max_open_disk_fds
2743 LOC: Config.max_open_disk_fds
2746 To avoid having disk as the I/O bottleneck Squid can optionally
2747 bypass the on-disk cache if more than this amount of disk file
2748 descriptors are open.
2750 A value of 0 indicates no limit.
2753 NAME: minimum_object_size
2757 LOC: Config.Store.minObjectSize
2759 Objects smaller than this size will NOT be saved on disk. The
2760 value is specified in kilobytes, and the default is 0 KB, which
2761 means there is no minimum.
2764 NAME: maximum_object_size
2768 LOC: Config.Store.maxObjectSize
2770 Objects larger than this size will NOT be saved on disk. The
2771 value is specified in kilobytes, and the default is 4MB. If
2772 you wish to get a high BYTES hit ratio, you should probably
2773 increase this (one 32 MB object hit counts for 3200 10KB
2774 hits). If you wish to increase speed more than your want to
2775 save bandwidth you should leave this low.
2777 NOTE: if using the LFUDA replacement policy you should increase
2778 this value to maximize the byte hit rate improvement of LFUDA!
2779 See replacement_policy below for a discussion of this policy.
2782 NAME: cache_swap_low
2783 COMMENT: (percent, 0-100)
2786 LOC: Config.Swap.lowWaterMark
2789 NAME: cache_swap_high
2790 COMMENT: (percent, 0-100)
2793 LOC: Config.Swap.highWaterMark
2796 The low- and high-water marks for cache object replacement.
2797 Replacement begins when the swap (disk) usage is above the
2798 low-water mark and attempts to maintain utilization near the
2799 low-water mark. As swap utilization gets close to high-water
2800 mark object eviction becomes more aggressive. If utilization is
2801 close to the low-water mark less replacement is done each time.
2803 Defaults are 90% and 95%. If you have a large cache, 5% could be
2804 hundreds of MB. If this is the case you may wish to set these
2805 numbers closer together.
2810 -----------------------------------------------------------------------------
2815 LOC: Config.Log.logformats
2820 logformat <name> <format specification>
2822 Defines an access log format.
2824 The <format specification> is a string with embedded % format codes
2826 % format codes all follow the same basic structure where all but
2827 the formatcode is optional. Output strings are automatically escaped
2828 as required according to their context and the output format
2829 modifiers are usually not needed, but can be specified if an explicit
2830 output format is desired.
2832 % ["|[|'|#] [-] [[0]width] [{argument}] formatcode
2834 " output in quoted string format
2835 [ output in squid text log format as used by log_mime_hdrs
2836 # output in URL quoted format
2840 width field width. If starting with 0 the
2841 output is zero padded
2842 {arg} argument such as header name etc
2846 % a literal % character
2847 sn Unique sequence number per log line entry
2848 err_code The ID of an error response served by Squid or
2849 a similar internal error identifier.
2850 err_detail Additional err_code-dependent error information.
2852 Connection related format codes:
2854 >a Client source IP address
2856 >p Client source port
2857 <A Server IP address or peer name
2858 la Local IP address (http_port)
2859 lp Local port number (http_port)
2860 <lp Local port number of the last server or peer connection
2862 Time related format codes:
2864 ts Seconds since epoch
2865 tu subsecond time (milliseconds)
2866 tl Local time. Optional strftime format argument
2867 default %d/%b/%Y:%H:%M:%S %z
2868 tg GMT time. Optional strftime format argument
2869 default %d/%b/%Y:%H:%M:%S %z
2870 tr Response time (milliseconds)
2871 dt Total time spent making DNS lookups (milliseconds)
2873 HTTP cache related format codes:
2875 [http::]>h Original request header. Optional header name argument
2876 on the format header[:[separator]element]
2877 [http::]>ha The HTTP request headers after adaptation and redirection.
2878 Optional header name argument as for >h
2879 [http::]<h Reply header. Optional header name argument
2881 [http::]un User name
2882 [http::]ul User name from authentication
2883 [http::]ui User name from ident
2884 [http::]us User name from SSL
2885 [http::]ue User name from external acl helper
2886 [http::]>Hs HTTP status code sent to the client
2887 [http::]<Hs HTTP status code received from the next hop
2888 [http::]<bs Number of HTTP-equivalent message body bytes
2889 received from the next hop, excluding chunked
2890 transfer encoding and control messages.
2891 Generated FTP/Gopher listings are treated as
2893 [http::]Ss Squid request status (TCP_MISS etc)
2894 [http::]Sh Squid hierarchy status (DEFAULT_PARENT etc)
2895 [http::]mt MIME content type
2896 [http::]rm Request method (GET/POST etc)
2897 [http::]ru Request URL
2898 [http::]rp Request URL-Path excluding hostname
2899 [http::]rv Request protocol version
2900 [http::]et Tag returned by external acl
2901 [http::]ea Log string returned by external acl
2902 [http::]<st Sent reply size including HTTP headers
2903 [http::]>st Received request size including HTTP headers. In the
2904 case of chunked requests the chunked encoding metadata
2906 [http::]>sh Received HTTP request headers size
2907 [http::]<sh Sent HTTP reply headers size
2908 [http::]st Request+Reply size including HTTP headers
2909 [http::]<sH Reply high offset sent
2910 [http::]<sS Upstream object size
2911 [http::]<pt Peer response time in milliseconds. The timer starts
2912 when the last request byte is sent to the next hop
2913 and stops when the last response byte is received.
2914 [http::]<tt Total server-side time in milliseconds. The timer
2915 starts with the first connect request (or write I/O)
2916 sent to the first selected peer. The timer stops
2917 with the last I/O with the last peer.
2919 If ICAP is enabled, the following two codes become available (as
2920 well as ICAP log codes documented with the icap_log option):
2922 icap::tt Total ICAP processing time for the HTTP
2923 transaction. The timer ticks when ICAP
2924 ACLs are checked and when ICAP
2925 transaction is in progress.
2927 icap::<last_h The header of the last ICAP response
2928 related to the HTTP transaction. Like
2929 <h, accepts an optional header name
2930 argument. Will not change semantics
2931 when multiple ICAP transactions per HTTP
2932 transaction are supported.
2934 If adaptation is enabled the following two codes become available:
2936 adapt::sum_trs Summed adaptation transaction response
2937 times recorded as a comma-separated list in
2938 the order of transaction start time. Each time
2939 value is recorded as an integer number,
2940 representing response time of one or more
2941 adaptation (ICAP or eCAP) transaction in
2942 milliseconds. When a failed transaction is
2943 being retried or repeated, its time is not
2944 logged individually but added to the
2945 replacement (next) transaction. See also:
2948 adapt::all_trs All adaptation transaction response times.
2949 Same as adaptation_strs but response times of
2950 individual transactions are never added
2951 together. Instead, all transaction response
2952 times are recorded individually.
2954 You can prefix adapt::*_trs format codes with adaptation
2955 service name in curly braces to record response time(s) specific
2956 to that service. For example: %{my_service}adapt::sum_trs
2958 The default formats available (which do not need re-defining) are:
2960 logformat squid %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %un %Sh/%<A %mt
2961 logformat squidmime %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %un %Sh/%<A %mt [%>h] [%<h]
2962 logformat common %>a %ui %un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st %Ss:%Sh
2963 logformat combined %>a %ui %un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
2966 NAME: access_log cache_access_log
2968 LOC: Config.Log.accesslogs
2969 DEFAULT_IF_NONE: daemon:@DEFAULT_ACCESS_LOG@ squid
2971 These files log client request activities. Has a line every HTTP or
2972 ICP request. The format is:
2973 access_log <module>:<place> [<logformat name> [acl acl ...]]
2974 access_log none [acl acl ...]]
2976 Will log to the specified module:place using the specified format (which
2977 must be defined in a logformat directive) those entries which match
2978 ALL the acl's specified (which must be defined in acl clauses).
2979 If no acl is specified, all requests will be logged to this destination.
2981 ===== Modules Currently available =====
2983 none Do not log any requests matching these ACL.
2984 Do not specify Place or logformat name.
2986 stdio Write each log line to disk immediately at the completion of
2988 Place: the filename and path to be written.
2990 daemon Very similar to stdio. But instead of writing to disk the log
2991 line is passed to a daemon helper for asychronous handling instead.
2992 Place: varies depending on the daemon.
2994 log_file_daemon Place: the file name and path to be written.
2996 syslog To log each request via syslog facility.
2997 Place: The syslog facility and priority level for these entries.
2998 Place Format: facility.priority
3000 where facility could be any of:
3001 authpriv, daemon, local0 ... local7 or user.
3003 And priority could be any of:
3004 err, warning, notice, info, debug.
3006 udp To send each log line as text data to a UDP receiver.
3007 Place: The destination host name or IP and port.
3008 Place Format: \\host:port
3010 tcp To send each log line as text data to a TCP receiver.
3011 Place: The destination host name or IP and port.
3012 Place Format: \\host:port
3015 access_log daemon:@DEFAULT_ACCESS_LOG@ squid
3021 LOC: Config.Log.icaplogs
3024 ICAP log files record ICAP transaction summaries, one line per
3027 The icap_log option format is:
3028 icap_log <filepath> [<logformat name> [acl acl ...]]
3029 icap_log none [acl acl ...]]
3031 Please see access_log option documentation for details. The two
3032 kinds of logs share the overall configuration approach and many
3035 ICAP processing of a single HTTP message or transaction may
3036 require multiple ICAP transactions. In such cases, multiple
3037 ICAP transaction log lines will correspond to a single access
3040 ICAP log uses logformat codes that make sense for an ICAP
3041 transaction. Header-related codes are applied to the HTTP header
3042 embedded in an ICAP server response, with the following caveats:
3043 For REQMOD, there is no HTTP response header unless the ICAP
3044 server performed request satisfaction. For RESPMOD, the HTTP
3045 request header is the header sent to the ICAP server. For
3046 OPTIONS, there are no HTTP headers.
3048 The following format codes are also available for ICAP logs:
3050 icap::<A ICAP server IP address. Similar to <A.
3052 icap::<service_name ICAP service name from the icap_service
3053 option in Squid configuration file.
3055 icap::ru ICAP Request-URI. Similar to ru.
3057 icap::rm ICAP request method (REQMOD, RESPMOD, or
3058 OPTIONS). Similar to existing rm.
3060 icap::>st Bytes sent to the ICAP server (TCP payload
3061 only; i.e., what Squid writes to the socket).
3063 icap::<st Bytes received from the ICAP server (TCP
3064 payload only; i.e., what Squid reads from
3067 icap::<bs Number of message body bytes received from the
3068 ICAP server. ICAP message body, if any, usually
3069 includes encapsulated HTTP message headers and
3070 possibly encapsulated HTTP message body. The
3071 HTTP body part is dechunked before its size is
3074 icap::tr Transaction response time (in
3075 milliseconds). The timer starts when
3076 the ICAP transaction is created and
3077 stops when the transaction is completed.
3080 icap::tio Transaction I/O time (in milliseconds). The
3081 timer starts when the first ICAP request
3082 byte is scheduled for sending. The timers
3083 stops when the last byte of the ICAP response
3086 icap::to Transaction outcome: ICAP_ERR* for all
3087 transaction errors, ICAP_OPT for OPTION
3088 transactions, ICAP_ECHO for 204
3089 responses, ICAP_MOD for message
3090 modification, and ICAP_SAT for request
3091 satisfaction. Similar to Ss.
3093 icap::Hs ICAP response status code. Similar to Hs.
3095 icap::>h ICAP request header(s). Similar to >h.
3097 icap::<h ICAP response header(s). Similar to <h.
3099 The default ICAP log format, which can be used without an explicit
3100 definition, is called icap_squid:
3102 logformat icap_squid %ts.%03tu %6icap::tr %>a %icap::to/%03icap::Hs %icap::<size %icap::rm %icap::ru% %un -/%icap::<A -
3104 See also: logformat, log_icap, and %icap::<last_h
3107 NAME: logfile_daemon
3109 DEFAULT: @DEFAULT_LOGFILED@
3110 LOC: Log::TheConfig.logfile_daemon
3112 Specify the path to the logfile-writing daemon. This daemon is
3113 used to write the access and store logs, if configured.
3115 Squid sends a number of commands to the log daemon:
3116 L<data>\n - logfile data
3121 r<n>\n - set rotate count to <n>
3122 b<n>\n - 1 = buffer output, 0 = don't buffer output
3124 No responses is expected.
3129 LOC: Config.accessList.log
3131 COMMENT: allow|deny acl acl...
3133 This options allows you to control which requests gets logged
3134 to access.log (see access_log directive). Requests denied for
3135 logging will also not be accounted for in performance counters.
3137 This clause only supports fast acl types.
3138 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
3144 LOC: Config.accessList.icap
3147 This options allows you to control which requests get logged
3148 to icap.log. See the icap_log directive for ICAP log details.
3151 NAME: cache_store_log
3154 LOC: Config.Log.store
3156 Logs the activities of the storage manager. Shows which
3157 objects are ejected from the cache, and which objects are
3158 saved and for how long. To disable, enter "none" or remove the line.
3159 There are not really utilities to analyze this data, so you can safely
3163 cache_store_log @DEFAULT_STORE_LOG@
3166 NAME: cache_swap_state cache_swap_log
3168 LOC: Config.Log.swap
3171 Location for the cache "swap.state" file. This index file holds
3172 the metadata of objects saved on disk. It is used to rebuild
3173 the cache during startup. Normally this file resides in each
3174 'cache_dir' directory, but you may specify an alternate
3175 pathname here. Note you must give a full filename, not just
3176 a directory. Since this is the index for the whole object
3177 list you CANNOT periodically rotate it!
3179 If %s can be used in the file name it will be replaced with a
3180 a representation of the cache_dir name where each / is replaced
3181 with '.'. This is needed to allow adding/removing cache_dir
3182 lines when cache_swap_log is being used.
3184 If have more than one 'cache_dir', and %s is not used in the name
3185 these swap logs will have names such as:
3191 The numbered extension (which is added automatically)
3192 corresponds to the order of the 'cache_dir' lines in this
3193 configuration file. If you change the order of the 'cache_dir'
3194 lines in this file, these index files will NOT correspond to
3195 the correct 'cache_dir' entry (unless you manually rename
3196 them). We recommend you do NOT use this option. It is
3197 better to keep these index files in each 'cache_dir' directory.
3200 NAME: logfile_rotate
3203 LOC: Config.Log.rotateNumber
3205 Specifies the number of logfile rotations to make when you
3206 type 'squid -k rotate'. The default is 10, which will rotate
3207 with extensions 0 through 9. Setting logfile_rotate to 0 will
3208 disable the file name rotation, but the logfiles are still closed
3209 and re-opened. This will enable you to rename the logfiles
3210 yourself just before sending the rotate signal.
3212 Note, the 'squid -k rotate' command normally sends a USR1
3213 signal to the running squid process. In certain situations
3214 (e.g. on Linux with Async I/O), USR1 is used for other
3215 purposes, so -k rotate uses another signal. It is best to get
3216 in the habit of using 'squid -k rotate' instead of 'kill -USR1
3219 Note, from Squid-3.1 this option has no effect on the cache.log,
3220 that log can be rotated separately by using debug_options
3223 NAME: emulate_httpd_log
3227 LOC: Config.onoff.common_log
3229 The Cache can emulate the log file format which many 'httpd'
3230 programs use. To disable/enable this emulation, set
3231 emulate_httpd_log to 'off' or 'on'. The default
3232 is to use the native log format since it includes useful
3233 information Squid-specific log analyzers use.
3236 NAME: log_ip_on_direct
3240 LOC: Config.onoff.log_ip_on_direct
3242 Log the destination IP address in the hierarchy log tag when going
3243 direct. Earlier Squid versions logged the hostname here. If you
3244 prefer the old way set this to off.
3249 DEFAULT: @DEFAULT_MIME_TABLE@
3250 LOC: Config.mimeTablePathname
3252 Pathname to Squid's MIME table. You shouldn't need to change
3253 this, but the default file contains examples and formatting
3254 information if you do.
3260 LOC: Config.onoff.log_mime_hdrs
3263 The Cache can record both the request and the response MIME
3264 headers for each HTTP transaction. The headers are encoded
3265 safely and will appear as two bracketed fields at the end of
3266 the access log (for either the native or httpd-emulated log
3267 formats). To enable this logging set log_mime_hdrs to 'on'.
3272 LOC: Config.Log.useragent
3274 IFDEF: USE_USERAGENT_LOG
3276 Squid will write the User-Agent field from HTTP requests
3277 to the filename specified here. By default useragent_log
3281 NAME: referer_log referrer_log
3283 LOC: Config.Log.referer
3285 IFDEF: USE_REFERER_LOG
3287 Squid will write the Referer field from HTTP requests to the
3288 filename specified here. By default referer_log is disabled.
3289 Note that "referer" is actually a misspelling of "referrer"
3290 however the misspelt version has been accepted into the HTTP RFCs
3296 DEFAULT: @DEFAULT_PID_FILE@
3297 LOC: Config.pidFilename
3299 A filename to write the process-id to. To disable, enter "none".
3305 Remove this option from your config. To log FQDN use %>A in the log format.
3308 NAME: client_netmask
3310 LOC: Config.Addrs.client_netmask
3313 A netmask for client addresses in logfiles and cachemgr output.
3314 Change this to protect the privacy of your cache clients.
3315 A netmask of 255.255.255.0 will log all IP's in that range with
3316 the last digit set to '0'.
3323 LOC: Config.Log.forward
3325 Logs the server-side requests.
3327 This is currently work in progress.
3330 NAME: strip_query_terms
3332 LOC: Config.onoff.strip_query_terms
3335 By default, Squid strips query terms from requested URLs before
3336 logging. This protects your user's privacy.
3343 LOC: Config.onoff.buffered_logs
3345 cache.log log file is written with stdio functions, and as such
3346 it can be buffered or unbuffered. By default it will be unbuffered.
3347 Buffering it can speed up the writing slightly (though you are
3348 unlikely to need to worry unless you run with tons of debugging
3349 enabled in which case performance will suffer badly anyway..).
3352 NAME: netdb_filename
3354 DEFAULT: @DEFAULT_NETDB_FILE@
3355 LOC: Config.netdbFilename
3358 A filename where Squid stores it's netdb state between restarts.
3359 To disable, enter "none".
3363 OPTIONS FOR TROUBLESHOOTING
3364 -----------------------------------------------------------------------------
3369 DEFAULT_IF_NONE: @DEFAULT_CACHE_LOG@
3370 LOC: Debug::cache_log
3372 Cache logging file. This is where general information about
3373 your cache's behavior goes. You can increase the amount of data
3374 logged to this file and how often its rotated with "debug_options"
3380 LOC: Debug::debugOptions
3382 Logging options are set as section,level where each source file
3383 is assigned a unique section. Lower levels result in less
3384 output, Full debugging (level 9) can result in a very large
3385 log file, so be careful.
3387 The magic word "ALL" sets debugging levels for all sections.
3388 We recommend normally running with "ALL,1".
3390 The rotate=N option can be used to keep more or less of these logs
3391 than would otherwise be kept by logfile_rotate.
3392 For most uses a single log should be enough to monitor current
3393 events affecting Squid.
3398 LOC: Config.coredump_dir
3399 DEFAULT_IF_NONE: none
3401 By default Squid leaves core files in the directory from where
3402 it was started. If you set 'coredump_dir' to a directory
3403 that exists, Squid will chdir() to that directory at startup
3404 and coredump files will be left there.
3408 # Leave coredumps in the first cache dir
3409 coredump_dir @DEFAULT_SWAP_DIR@
3415 OPTIONS FOR FTP GATEWAYING
3416 -----------------------------------------------------------------------------
3422 LOC: Config.Ftp.anon_user
3424 If you want the anonymous login password to be more informative
3425 (and enable the use of picky ftp servers), set this to something
3426 reasonable for your domain, like wwwuser@somewhere.net
3428 The reason why this is domainless by default is the
3429 request can be made on the behalf of a user in any domain,
3430 depending on how the cache is used.
3431 Some ftp server also validate the email address is valid
3432 (for example perl.com).
3438 LOC: Config.Ftp.passive
3440 If your firewall does not allow Squid to use passive
3441 connections, turn off this option.
3443 Use of ftp_epsv_all option requires this to be ON.
3449 LOC: Config.Ftp.epsv_all
3451 FTP Protocol extensions permit the use of a special "EPSV ALL" command.
3453 NATs may be able to put the connection on a "fast path" through the
3454 translator, as the EPRT command will never be used and therefore,
3455 translation of the data portion of the segments will never be needed.
3457 When a client only expects to do two-way FTP transfers this may be
3459 If squid finds that it must do a three-way FTP transfer after issuing
3460 an EPSV ALL command, the FTP session will fail.
3462 If you have any doubts about this option do not use it.
3463 Squid will nicely attempt all other connection methods.
3465 Requires ftp_passive to be ON (default) for any effect.
3471 LOC: Config.Ftp.epsv
3473 FTP Protocol extensions permit the use of a special "EPSV" command.
3475 NATs may be able to put the connection on a "fast path" through the
3476 translator using EPSV, as the EPRT command will never be used
3477 and therefore, translation of the data portion of the segments
3478 will never be needed.
3480 Turning this OFF will prevent EPSV being attempted.
3481 WARNING: Doing so will convert Squid back to the old behavior with all
3482 the related problems with external NAT devices/layers.
3484 Requires ftp_passive to be ON (default) for any effect.
3487 NAME: ftp_sanitycheck
3490 LOC: Config.Ftp.sanitycheck
3492 For security and data integrity reasons Squid by default performs
3493 sanity checks of the addresses of FTP data connections ensure the
3494 data connection is to the requested server. If you need to allow
3495 FTP connections to servers using another IP address for the data
3496 connection turn this off.
3499 NAME: ftp_telnet_protocol
3502 LOC: Config.Ftp.telnet
3504 The FTP protocol is officially defined to use the telnet protocol
3505 as transport channel for the control connection. However, many
3506 implementations are broken and does not respect this aspect of
3509 If you have trouble accessing files with ASCII code 255 in the
3510 path or similar problems involving this ASCII code you can
3511 try setting this directive to off. If that helps, report to the
3512 operator of the FTP server in question that their FTP server
3513 is broken and does not follow the FTP standard.
3517 OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
3518 -----------------------------------------------------------------------------
3523 DEFAULT: @DEFAULT_DISKD@
3524 LOC: Config.Program.diskd
3526 Specify the location of the diskd executable.
3527 Note this is only useful if you have compiled in
3528 diskd as one of the store io modules.
3531 NAME: unlinkd_program
3534 DEFAULT: @DEFAULT_UNLINKD@
3535 LOC: Config.Program.unlinkd
3537 Specify the location of the executable for file deletion process.
3540 NAME: pinger_program
3542 DEFAULT: @DEFAULT_PINGER@
3543 LOC: Config.pinger.program
3546 Specify the location of the executable for the pinger process.
3552 LOC: Config.pinger.enable
3555 Control whether the pinger is active at run-time.
3556 Enables turning ICMP pinger on and off with a simple
3557 squid -k reconfigure.
3562 OPTIONS FOR URL REWRITING
3563 -----------------------------------------------------------------------------
3566 NAME: url_rewrite_program redirect_program
3568 LOC: Config.Program.redirect
3571 Specify the location of the executable for the URL rewriter.
3572 Since they can perform almost any function there isn't one included.
3574 For each requested URL rewriter will receive on line with the format
3576 URL <SP> client_ip "/" fqdn <SP> user <SP> method [<SP> kvpairs]<NL>
3578 In the future, the rewriter interface will be extended with
3579 key=value pairs ("kvpairs" shown above). Rewriter programs
3580 should be prepared to receive and possibly ignore additional
3581 whitespace-separated tokens on each input line.
3583 And the rewriter may return a rewritten URL. The other components of
3584 the request line does not need to be returned (ignored if they are).
3586 The rewriter can also indicate that a client-side redirect should
3587 be performed to the new URL. This is done by prefixing the returned
3588 URL with "301:" (moved permanently) or 302: (moved temporarily).
3590 By default, a URL rewriter is not used.
3593 NAME: url_rewrite_children redirect_children
3594 TYPE: HelperChildConfig
3595 DEFAULT: 20 startup=0 idle=1 concurrency=0
3596 LOC: Config.redirectChildren
3598 The maximum number of redirector processes to spawn. If you limit
3599 it too few Squid will have to wait for them to process a backlog of
3600 URLs, slowing it down. If you allow too many they will use RAM
3601 and other system resources noticably.
3603 The startup= and idle= options allow some measure of skew in your
3608 Sets a minimum of how many processes are to be spawned when Squid
3609 starts or reconfigures. When set to zero the first request will
3610 cause spawning of the first child process to handle it.
3612 Starting too few will cause an initial slowdown in traffic as Squid
3613 attempts to simultaneously spawn enough processes to cope.
3617 Sets a minimum of how many processes Squid is to try and keep available
3618 at all times. When traffic begins to rise above what the existing
3619 processes can handle this many more will be spawned up to the maximum
3620 configured. A minimum setting of 1 is required.
3624 The number of requests each redirector helper can handle in
3625 parallel. Defaults to 0 which indicates the redirector
3626 is a old-style single threaded redirector.
3628 When this directive is set to a value >= 1 then the protocol
3629 used to communicate with the helper is modified to include
3630 a request ID in front of the request/response. The request
3631 ID from the request must be echoed back with the response
3635 NAME: url_rewrite_host_header redirect_rewrites_host_header
3638 LOC: Config.onoff.redir_rewrites_host
3640 By default Squid rewrites any Host: header in redirected
3641 requests. If you are running an accelerator this may
3642 not be a wanted effect of a redirector.
3644 WARNING: Entries are cached on the result of the URL rewriting
3645 process, so be careful if you have domain-virtual hosts.
3648 NAME: url_rewrite_access redirector_access
3651 LOC: Config.accessList.redirector
3653 If defined, this access list specifies which requests are
3654 sent to the redirector processes. By default all requests
3657 This clause supports both fast and slow acl types.
3658 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
3661 NAME: url_rewrite_bypass redirector_bypass
3663 LOC: Config.onoff.redirector_bypass
3666 When this is 'on', a request will not go through the
3667 redirector if all redirectors are busy. If this is 'off'
3668 and the redirector queue grows too large, Squid will exit
3669 with a FATAL error and ask you to increase the number of
3670 redirectors. You should only enable this if the redirectors
3671 are not critical to your caching system. If you use
3672 redirectors for access control, and you enable this option,
3673 users may have access to pages they should not
3674 be allowed to request.
3678 OPTIONS FOR TUNING THE CACHE
3679 -----------------------------------------------------------------------------
3682 NAME: cache no_cache
3685 LOC: Config.accessList.noCache
3687 A list of ACL elements which, if matched and denied, cause the request to
3688 not be satisfied from the cache and the reply to not be cached.
3689 In other words, use this to force certain objects to never be cached.
3691 You must use the words 'allow' or 'deny' to indicate whether items
3692 matching the ACL should be allowed or denied into the cache.
3694 Default is to allow all to be cached.
3696 This clause supports both fast and slow acl types.
3697 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
3700 NAME: refresh_pattern
3701 TYPE: refreshpattern
3705 usage: refresh_pattern [-i] regex min percent max [options]
3707 By default, regular expressions are CASE-SENSITIVE. To make
3708 them case-insensitive, use the -i option.
3710 'Min' is the time (in minutes) an object without an explicit
3711 expiry time should be considered fresh. The recommended
3712 value is 0, any higher values may cause dynamic applications
3713 to be erroneously cached unless the application designer
3714 has taken the appropriate actions.
3716 'Percent' is a percentage of the objects age (time since last
3717 modification age) an object without explicit expiry time
3718 will be considered fresh.
3720 'Max' is an upper limit on how long objects without an explicit
3721 expiry time will be considered fresh.
3723 options: override-expire
3729 ignore-must-revalidate
3735 override-expire enforces min age even if the server
3736 sent an explicit expiry time (e.g., with the
3737 Expires: header or Cache-Control: max-age). Doing this
3738 VIOLATES the HTTP standard. Enabling this feature
3739 could make you liable for problems which it causes.
3741 Note: override-expire does not enforce staleness - it only extends
3742 freshness / min. If the server returns a Expires time which
3743 is longer than your max time, Squid will still consider
3744 the object fresh for that period of time.
3746 override-lastmod enforces min age even on objects
3747 that were modified recently.
3749 reload-into-ims changes client no-cache or ``reload''
3750 to If-Modified-Since requests. Doing this VIOLATES the
3751 HTTP standard. Enabling this feature could make you
3752 liable for problems which it causes.
3754 ignore-reload ignores a client no-cache or ``reload''
3755 header. Doing this VIOLATES the HTTP standard. Enabling
3756 this feature could make you liable for problems which
3759 ignore-no-cache ignores any ``Pragma: no-cache'' and
3760 ``Cache-control: no-cache'' headers received from a server.
3761 The HTTP RFC never allows the use of this (Pragma) header
3762 from a server, only a client, though plenty of servers
3765 ignore-no-store ignores any ``Cache-control: no-store''
3766 headers received from a server. Doing this VIOLATES
3767 the HTTP standard. Enabling this feature could make you
3768 liable for problems which it causes.
3770 ignore-must-revalidate ignores any ``Cache-Control: must-revalidate``
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-private ignores any ``Cache-control: private''
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-auth caches responses to requests with authorization,
3781 as if the originserver had sent ``Cache-control: public''
3782 in the response header. Doing this VIOLATES the HTTP standard.
3783 Enabling this feature could make you liable for problems which
3786 refresh-ims causes squid to contact the origin server
3787 when a client issues an If-Modified-Since request. This
3788 ensures that the client will receive an updated version
3789 if one is available.
3791 store-stale stores responses even if they don't have explicit
3792 freshness or a validator (i.e., Last-Modified or an ETag)
3793 present, or if they're already stale. By default, Squid will
3794 not cache such responses because they usually can't be
3795 reused. Note that such responses will be stale by default.
3797 Basically a cached object is:
3799 FRESH if expires < now, else STALE
3801 FRESH if lm-factor < percent, else STALE
3805 The refresh_pattern lines are checked in the order listed here.
3806 The first entry which matches is used. If none of the entries
3807 match the default will be used.
3809 Note, you must uncomment all the default lines if you want
3810 to change one. The default setting is only active if none is
3815 # Add any of your own refresh_pattern entries above these.
3816 refresh_pattern ^ftp: 1440 20% 10080
3817 refresh_pattern ^gopher: 1440 0% 1440
3818 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0
3819 refresh_pattern . 0 20% 4320
3823 NAME: quick_abort_min
3827 LOC: Config.quickAbort.min
3830 NAME: quick_abort_max
3834 LOC: Config.quickAbort.max
3837 NAME: quick_abort_pct
3841 LOC: Config.quickAbort.pct
3843 The cache by default continues downloading aborted requests
3844 which are almost completed (less than 16 KB remaining). This
3845 may be undesirable on slow (e.g. SLIP) links and/or very busy
3846 caches. Impatient users may tie up file descriptors and
3847 bandwidth by repeatedly requesting and immediately aborting
3850 When the user aborts a request, Squid will check the
3851 quick_abort values to the amount of data transfered until
3854 If the transfer has less than 'quick_abort_min' KB remaining,
3855 it will finish the retrieval.
3857 If the transfer has more than 'quick_abort_max' KB remaining,
3858 it will abort the retrieval.
3860 If more than 'quick_abort_pct' of the transfer has completed,
3861 it will finish the retrieval.
3863 If you do not want any retrieval to continue after the client
3864 has aborted, set both 'quick_abort_min' and 'quick_abort_max'
3867 If you want retrievals to always continue if they are being
3868 cached set 'quick_abort_min' to '-1 KB'.
3871 NAME: read_ahead_gap
3872 COMMENT: buffer-size
3874 LOC: Config.readAheadGap
3877 The amount of data the cache will buffer ahead of what has been
3878 sent to the client when retrieving an object from another server.
3882 IFDEF: USE_HTTP_VIOLATIONS
3885 LOC: Config.negativeTtl
3888 Set the Default Time-to-Live (TTL) for failed requests.
3889 Certain types of failures (such as "connection refused" and
3890 "404 Not Found") are able to be negatively-cached for a short time.
3891 Modern web servers should provide Expires: header, however if they
3892 do not this can provide a minimum TTL.
3893 The default is not to cache errors with unknown expiry details.
3895 Note that this is different from negative caching of DNS lookups.
3897 WARNING: Doing this VIOLATES the HTTP standard. Enabling
3898 this feature could make you liable for problems which it
3902 NAME: positive_dns_ttl
3905 LOC: Config.positiveDnsTtl
3908 Upper limit on how long Squid will cache positive DNS responses.
3909 Default is 6 hours (360 minutes). This directive must be set
3910 larger than negative_dns_ttl.
3913 NAME: negative_dns_ttl
3916 LOC: Config.negativeDnsTtl
3919 Time-to-Live (TTL) for negative caching of failed DNS lookups.
3920 This also sets the lower cache limit on positive lookups.
3921 Minimum value is 1 second, and it is not recommendable to go
3922 much below 10 seconds.
3925 NAME: range_offset_limit
3926 COMMENT: size [acl acl...]
3928 LOC: Config.rangeOffsetLimit
3931 usage: (size) [units] [[!]aclname]
3933 Sets an upper limit on how far (number of bytes) into the file
3934 a Range request may be to cause Squid to prefetch the whole file.
3935 If beyond this limit, Squid forwards the Range request as it is and
3936 the result is NOT cached.
3938 This is to stop a far ahead range request (lets say start at 17MB)
3939 from making Squid fetch the whole object up to that point before
3940 sending anything to the client.
3942 Multiple range_offset_limit lines may be specified, and they will
3943 be searched from top to bottom on each request until a match is found.
3944 The first match found will be used. If no line matches a request, the
3945 default limit of 0 bytes will be used.
3947 'size' is the limit specified as a number of units.
3949 'units' specifies whether to use bytes, KB, MB, etc.
3950 If no units are specified bytes are assumed.
3952 A size of 0 causes Squid to never fetch more than the
3953 client requested. (default)
3955 A size of 'none' causes Squid to always fetch the object from the
3956 beginning so it may cache the result. (2.0 style)
3958 'aclname' is the name of a defined ACL.
3960 NP: Using 'none' as the byte value here will override any quick_abort settings
3961 that may otherwise apply to the range request. The range request will
3962 be fully fetched from start to finish regardless of the client
3963 actions. This affects bandwidth usage.
3966 NAME: minimum_expiry_time
3969 LOC: Config.minimum_expiry_time
3972 The minimum caching time according to (Expires - Date)
3973 Headers Squid honors if the object can't be revalidated
3974 defaults to 60 seconds. In reverse proxy environments it
3975 might be desirable to honor shorter object lifetimes. It
3976 is most likely better to make your server return a
3977 meaningful Last-Modified header however. In ESI environments
3978 where page fragments often have short lifetimes, this will
3979 often be best set to 0.
3982 NAME: store_avg_object_size
3986 LOC: Config.Store.avgObjectSize
3988 Average object size, used to estimate number of objects your
3989 cache can hold. The default is 13 KB.
3992 NAME: store_objects_per_bucket
3995 LOC: Config.Store.objectsPerBucket
3997 Target number of objects per bucket in the store hash table.
3998 Lowering this value increases the total number of buckets and
3999 also the storage maintenance rate. The default is 20.
4004 -----------------------------------------------------------------------------
4007 NAME: request_header_max_size
4011 LOC: Config.maxRequestHeaderSize
4013 This specifies the maximum size for HTTP headers in a request.
4014 Request headers are usually relatively small (about 512 bytes).
4015 Placing a limit on the request header size will catch certain
4016 bugs (for example with persistent connections) and possibly
4017 buffer-overflow or denial-of-service attacks.
4020 NAME: reply_header_max_size
4024 LOC: Config.maxReplyHeaderSize
4026 This specifies the maximum size for HTTP headers in a reply.
4027 Reply headers are usually relatively small (about 512 bytes).
4028 Placing a limit on the reply header size will catch certain
4029 bugs (for example with persistent connections) and possibly
4030 buffer-overflow or denial-of-service attacks.
4033 NAME: request_body_max_size
4037 LOC: Config.maxRequestBodySize
4039 This specifies the maximum size for an HTTP request body.
4040 In other words, the maximum size of a PUT/POST request.
4041 A user who attempts to send a request with a body larger
4042 than this limit receives an "Invalid Request" error message.
4043 If you set this parameter to a zero (the default), there will
4044 be no limit imposed.
4047 NAME: chunked_request_body_max_size
4051 LOC: Config.maxChunkedRequestBodySize
4053 A broken or confused HTTP/1.1 client may send a chunked HTTP
4054 request to Squid. Squid does not have full support for that
4055 feature yet. To cope with such requests, Squid buffers the
4056 entire request and then dechunks request body to create a
4057 plain HTTP/1.0 request with a known content length. The plain
4058 request is then used by the rest of Squid code as usual.
4060 The option value specifies the maximum size of the buffer used
4061 to hold the request before the conversion. If the chunked
4062 request size exceeds the specified limit, the conversion
4063 fails, and the client receives an "unsupported request" error,
4064 as if dechunking was disabled.
4066 Dechunking is enabled by default. To disable conversion of
4067 chunked requests, set the maximum to zero.
4069 Request dechunking feature and this option in particular are a
4070 temporary hack. When chunking requests and responses are fully
4071 supported, there will be no need to buffer a chunked request.
4075 IFDEF: USE_HTTP_VIOLATIONS
4078 LOC: Config.accessList.brokenPosts
4080 A list of ACL elements which, if matched, causes Squid to send
4081 an extra CRLF pair after the body of a PUT/POST request.
4083 Some HTTP servers has broken implementations of PUT/POST,
4084 and rely on an extra CRLF pair sent by some WWW clients.
4086 Quote from RFC2616 section 4.1 on this matter:
4088 Note: certain buggy HTTP/1.0 client implementations generate an
4089 extra CRLF's after a POST request. To restate what is explicitly
4090 forbidden by the BNF, an HTTP/1.1 client must not preface or follow
4091 a request with an extra CRLF.
4093 This clause only supports fast acl types.
4094 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4097 acl buggy_server url_regex ^http://....
4098 broken_posts allow buggy_server
4101 NAME: icap_uses_indirect_client
4104 IFDEF: FOLLOW_X_FORWARDED_FOR&&ICAP_CLIENT
4106 LOC: Adaptation::Icap::TheConfig.icap_uses_indirect_client
4108 Controls whether the indirect client address
4109 (see follow_x_forwarded_for) instead of the
4110 direct client address is passed to an ICAP
4111 server as "X-Client-IP".
4115 IFDEF: USE_HTTP_VIOLATIONS
4119 LOC: Config.onoff.via
4121 If set (default), Squid will include a Via header in requests and
4122 replies as required by RFC2616.
4128 LOC: Config.onoff.ie_refresh
4131 Microsoft Internet Explorer up until version 5.5 Service
4132 Pack 1 has an issue with transparent proxies, wherein it
4133 is impossible to force a refresh. Turning this on provides
4134 a partial fix to the problem, by causing all IMS-REFRESH
4135 requests from older IE versions to check the origin server
4136 for fresh content. This reduces hit ratio by some amount
4137 (~10% in my experience), but allows users to actually get
4138 fresh content when they want it. Note because Squid
4139 cannot tell if the user is using 5.5 or 5.5SP1, the behavior
4140 of 5.5 is unchanged from old versions of Squid (i.e. a
4141 forced refresh is impossible). Newer versions of IE will,
4142 hopefully, continue to have the new behavior and will be
4143 handled based on that assumption. This option defaults to
4144 the old Squid behavior, which is better for hit ratios but
4145 worse for clients using IE, if they need to be able to
4146 force fresh content.
4149 NAME: vary_ignore_expire
4152 LOC: Config.onoff.vary_ignore_expire
4155 Many HTTP servers supporting Vary gives such objects
4156 immediate expiry time with no cache-control header
4157 when requested by a HTTP/1.0 client. This option
4158 enables Squid to ignore such expiry times until
4159 HTTP/1.1 is fully implemented.
4161 WARNING: If turned on this may eventually cause some
4162 varying objects not intended for caching to get cached.
4165 NAME: request_entities
4167 LOC: Config.onoff.request_entities
4170 Squid defaults to deny GET and HEAD requests with request entities,
4171 as the meaning of such requests are undefined in the HTTP standard
4172 even if not explicitly forbidden.
4174 Set this directive to on if you have clients which insists
4175 on sending request entities in GET or HEAD requests. But be warned
4176 that there is server software (both proxies and web servers) which
4177 can fail to properly process this kind of request which may make you
4178 vulnerable to cache pollution attacks if enabled.
4181 NAME: request_header_access
4182 IFDEF: USE_HTTP_VIOLATIONS
4183 TYPE: http_header_access[]
4184 LOC: Config.request_header_access
4187 Usage: request_header_access header_name allow|deny [!]aclname ...
4189 WARNING: Doing this VIOLATES the HTTP standard. Enabling
4190 this feature could make you liable for problems which it
4193 This option replaces the old 'anonymize_headers' and the
4194 older 'http_anonymizer' option with something that is much
4195 more configurable. This new method creates a list of ACLs
4196 for each header, allowing you very fine-tuned header
4199 This option only applies to request headers, i.e., from the
4200 client to the server.
4202 You can only specify known headers for the header name.
4203 Other headers are reclassified as 'Other'. You can also
4204 refer to all the headers with 'All'.
4206 For example, to achieve the same behavior as the old
4207 'http_anonymizer standard' option, you should use:
4209 request_header_access From deny all
4210 request_header_access Referer deny all
4211 request_header_access Server deny all
4212 request_header_access User-Agent deny all
4213 request_header_access WWW-Authenticate deny all
4214 request_header_access Link deny all
4216 Or, to reproduce the old 'http_anonymizer paranoid' feature
4219 request_header_access Allow allow all
4220 request_header_access Authorization allow all
4221 request_header_access WWW-Authenticate allow all
4222 request_header_access Proxy-Authorization allow all
4223 request_header_access Proxy-Authenticate allow all
4224 request_header_access Cache-Control allow all
4225 request_header_access Content-Encoding allow all
4226 request_header_access Content-Length allow all
4227 request_header_access Content-Type allow all
4228 request_header_access Date allow all
4229 request_header_access Expires allow all
4230 request_header_access Host allow all
4231 request_header_access If-Modified-Since allow all
4232 request_header_access Last-Modified allow all
4233 request_header_access Location allow all
4234 request_header_access Pragma allow all
4235 request_header_access Accept allow all
4236 request_header_access Accept-Charset allow all
4237 request_header_access Accept-Encoding allow all
4238 request_header_access Accept-Language allow all
4239 request_header_access Content-Language allow all
4240 request_header_access Mime-Version allow all
4241 request_header_access Retry-After allow all
4242 request_header_access Title allow all
4243 request_header_access Connection allow all
4244 request_header_access All deny all
4246 although many of those are HTTP reply headers, and so should be
4247 controlled with the reply_header_access directive.
4249 By default, all headers are allowed (no anonymizing is
4253 NAME: reply_header_access
4254 IFDEF: USE_HTTP_VIOLATIONS
4255 TYPE: http_header_access[]
4256 LOC: Config.reply_header_access
4259 Usage: reply_header_access header_name allow|deny [!]aclname ...
4261 WARNING: Doing this VIOLATES the HTTP standard. Enabling
4262 this feature could make you liable for problems which it
4265 This option only applies to reply headers, i.e., from the
4266 server to the client.
4268 This is the same as request_header_access, but in the other
4271 This option replaces the old 'anonymize_headers' and the
4272 older 'http_anonymizer' option with something that is much
4273 more configurable. This new method creates a list of ACLs
4274 for each header, allowing you very fine-tuned header
4277 You can only specify known headers for the header name.
4278 Other headers are reclassified as 'Other'. You can also
4279 refer to all the headers with 'All'.
4281 For example, to achieve the same behavior as the old
4282 'http_anonymizer standard' option, you should use:
4284 reply_header_access From deny all
4285 reply_header_access Referer deny all
4286 reply_header_access Server deny all
4287 reply_header_access User-Agent deny all
4288 reply_header_access WWW-Authenticate deny all
4289 reply_header_access Link deny all
4291 Or, to reproduce the old 'http_anonymizer paranoid' feature
4294 reply_header_access Allow allow all
4295 reply_header_access Authorization allow all
4296 reply_header_access WWW-Authenticate allow all
4297 reply_header_access Proxy-Authorization allow all
4298 reply_header_access Proxy-Authenticate allow all
4299 reply_header_access Cache-Control allow all
4300 reply_header_access Content-Encoding allow all
4301 reply_header_access Content-Length allow all
4302 reply_header_access Content-Type allow all
4303 reply_header_access Date allow all
4304 reply_header_access Expires allow all
4305 reply_header_access Host allow all
4306 reply_header_access If-Modified-Since allow all
4307 reply_header_access Last-Modified allow all
4308 reply_header_access Location allow all
4309 reply_header_access Pragma allow all
4310 reply_header_access Accept allow all
4311 reply_header_access Accept-Charset allow all
4312 reply_header_access Accept-Encoding allow all
4313 reply_header_access Accept-Language allow all
4314 reply_header_access Content-Language allow all
4315 reply_header_access Mime-Version allow all
4316 reply_header_access Retry-After allow all
4317 reply_header_access Title allow all
4318 reply_header_access Connection allow all
4319 reply_header_access All deny all
4321 although the HTTP request headers won't be usefully controlled
4322 by this directive -- see request_header_access for details.
4324 By default, all headers are allowed (no anonymizing is
4328 NAME: header_replace
4329 IFDEF: USE_HTTP_VIOLATIONS
4330 TYPE: http_header_replace[]
4331 LOC: Config.request_header_access
4334 Usage: header_replace header_name message
4335 Example: header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
4337 This option allows you to change the contents of headers
4338 denied with header_access above, by replacing them with
4339 some fixed string. This replaces the old fake_user_agent
4342 This only applies to request headers, not reply headers.
4344 By default, headers are removed if denied.
4347 NAME: relaxed_header_parser
4348 COMMENT: on|off|warn
4350 LOC: Config.onoff.relaxed_header_parser
4353 In the default "on" setting Squid accepts certain forms
4354 of non-compliant HTTP messages where it is unambiguous
4355 what the sending application intended even if the message
4356 is not correctly formatted. The messages is then normalized
4357 to the correct form when forwarded by Squid.
4359 If set to "warn" then a warning will be emitted in cache.log
4360 each time such HTTP error is encountered.
4362 If set to "off" then such HTTP errors will cause the request
4363 or response to be rejected.
4368 -----------------------------------------------------------------------------
4371 NAME: forward_timeout
4374 LOC: Config.Timeout.forward
4377 This parameter specifies how long Squid should at most attempt in
4378 finding a forwarding path for the request before giving up.
4381 NAME: connect_timeout
4384 LOC: Config.Timeout.connect
4387 This parameter specifies how long to wait for the TCP connect to
4388 the requested server or peer to complete before Squid should
4389 attempt to find another path where to forward the request.
4392 NAME: peer_connect_timeout
4395 LOC: Config.Timeout.peer_connect
4398 This parameter specifies how long to wait for a pending TCP
4399 connection to a peer cache. The default is 30 seconds. You
4400 may also set different timeout values for individual neighbors
4401 with the 'connect-timeout' option on a 'cache_peer' line.
4407 LOC: Config.Timeout.read
4410 The read_timeout is applied on server-side connections. After
4411 each successful read(), the timeout will be extended by this
4412 amount. If no data is read again after this amount of time,
4413 the request is aborted and logged with ERR_READ_TIMEOUT. The
4414 default is 15 minutes.
4420 LOC: Config.Timeout.write
4423 This timeout is tracked for all connections that have data
4424 available for writing and are waiting for the socket to become
4425 ready. After each successful write, the timeout is extended by
4426 the configured amount. If Squid has data to write but the
4427 connection is not ready for the configured duration, the
4428 transaction associated with the connection is terminated. The
4429 default is 15 minutes.
4432 NAME: request_timeout
4434 LOC: Config.Timeout.request
4437 How long to wait for an HTTP request after initial
4438 connection establishment.
4441 NAME: persistent_request_timeout
4443 LOC: Config.Timeout.persistent_request
4446 How long to wait for the next HTTP request on a persistent
4447 connection after the previous request completes.
4450 NAME: client_lifetime
4453 LOC: Config.Timeout.lifetime
4456 The maximum amount of time a client (browser) is allowed to
4457 remain connected to the cache process. This protects the Cache
4458 from having a lot of sockets (and hence file descriptors) tied up
4459 in a CLOSE_WAIT state from remote clients that go away without
4460 properly shutting down (either because of a network failure or
4461 because of a poor client implementation). The default is one
4464 NOTE: The default value is intended to be much larger than any
4465 client would ever need to be connected to your cache. You
4466 should probably change client_lifetime only as a last resort.
4467 If you seem to have many client connections tying up
4468 filedescriptors, we recommend first tuning the read_timeout,
4469 request_timeout, persistent_request_timeout and quick_abort values.
4472 NAME: half_closed_clients
4474 LOC: Config.onoff.half_closed_clients
4477 Some clients may shutdown the sending side of their TCP
4478 connections, while leaving their receiving sides open. Sometimes,
4479 Squid can not tell the difference between a half-closed and a
4480 fully-closed TCP connection.
4482 By default, Squid will immediately close client connections when
4483 read(2) returns "no more data to read."
4485 Change this option to 'on' and Squid will keep open connections
4486 until a read(2) or write(2) on the socket returns an error.
4487 This may show some benefits for reverse proxies. But if not
4488 it is recommended to leave OFF.
4493 LOC: Config.Timeout.pconn
4496 Timeout for idle persistent connections to servers and other
4503 LOC: Ident::TheConfig.timeout
4506 Maximum time to wait for IDENT lookups to complete.
4508 If this is too high, and you enabled IDENT lookups from untrusted
4509 users, you might be susceptible to denial-of-service by having
4510 many ident requests going at once.
4513 NAME: shutdown_lifetime
4516 LOC: Config.shutdownLifetime
4519 When SIGTERM or SIGHUP is received, the cache is put into
4520 "shutdown pending" mode until all active sockets are closed.
4521 This value is the lifetime to set for all open descriptors
4522 during shutdown mode. Any active clients after this many
4523 seconds will receive a 'timeout' message.
4527 ADMINISTRATIVE PARAMETERS
4528 -----------------------------------------------------------------------------
4534 LOC: Config.adminEmail
4536 Email-address of local cache manager who will receive
4537 mail if the cache dies. The default is "webmaster."
4543 LOC: Config.EmailFrom
4545 From: email-address for mail sent when the cache dies.
4546 The default is to use 'appname@unique_hostname'.
4547 Default appname value is "squid", can be changed into
4548 src/globals.h before building squid.
4554 LOC: Config.EmailProgram
4556 Email program used to send mail if the cache dies.
4557 The default is "mail". The specified program must comply
4558 with the standard Unix mail syntax:
4559 mail-program recipient < mailfile
4561 Optional command line options can be specified.
4564 NAME: cache_effective_user
4566 DEFAULT: @DEFAULT_CACHE_EFFECTIVE_USER@
4567 LOC: Config.effectiveUser
4569 If you start Squid as root, it will change its effective/real
4570 UID/GID to the user specified below. The default is to change
4571 to UID of @DEFAULT_CACHE_EFFECTIVE_USER@.
4572 see also; cache_effective_group
4575 NAME: cache_effective_group
4578 LOC: Config.effectiveGroup
4580 Squid sets the GID to the effective user's default group ID
4581 (taken from the password file) and supplementary group list
4582 from the groups membership.
4584 If you want Squid to run with a specific GID regardless of
4585 the group memberships of the effective user then set this
4586 to the group (or GID) you want Squid to run as. When set
4587 all other group privileges of the effective user are ignored
4588 and only this GID is effective. If Squid is not started as
4589 root the user starting Squid MUST be member of the specified
4592 This option is not recommended by the Squid Team.
4593 Our preference is for administrators to configure a secure
4594 user account for squid with UID/GID matching system policies.
4597 NAME: httpd_suppress_version_string
4601 LOC: Config.onoff.httpd_suppress_version_string
4603 Suppress Squid version string info in HTTP headers and HTML error pages.
4606 NAME: visible_hostname
4608 LOC: Config.visibleHostname
4611 If you want to present a special hostname in error messages, etc,
4612 define this. Otherwise, the return value of gethostname()
4613 will be used. If you have multiple caches in a cluster and
4614 get errors about IP-forwarding you must set them to have individual
4615 names with this setting.
4618 NAME: unique_hostname
4620 LOC: Config.uniqueHostname
4623 If you want to have multiple machines with the same
4624 'visible_hostname' you must give each machine a different
4625 'unique_hostname' so forwarding loops can be detected.
4628 NAME: hostname_aliases
4630 LOC: Config.hostnameAliases
4633 A list of other DNS names your cache has.
4641 Minimum umask which should be enforced while the proxy
4642 is running, in addition to the umask set at startup.
4644 For a traditional octal representation of umasks, start
4649 OPTIONS FOR THE CACHE REGISTRATION SERVICE
4650 -----------------------------------------------------------------------------
4652 This section contains parameters for the (optional) cache
4653 announcement service. This service is provided to help
4654 cache administrators locate one another in order to join or
4655 create cache hierarchies.
4657 An 'announcement' message is sent (via UDP) to the registration
4658 service by Squid. By default, the announcement message is NOT
4659 SENT unless you enable it with 'announce_period' below.
4661 The announcement message includes your hostname, plus the
4662 following information from this configuration file:
4668 All current information is processed regularly and made
4669 available on the Web at http://www.ircache.net/Cache/Tracker/.
4672 NAME: announce_period
4674 LOC: Config.Announce.period
4677 This is how frequently to send cache announcements. The
4678 default is `0' which disables sending the announcement
4681 To enable announcing your cache, just set an announce period.
4684 announce_period 1 day
4689 DEFAULT: tracker.ircache.net
4690 LOC: Config.Announce.host
4696 LOC: Config.Announce.file
4702 LOC: Config.Announce.port
4704 announce_host and announce_port set the hostname and port
4705 number where the registration message will be sent.
4707 Hostname will default to 'tracker.ircache.net' and port will
4708 default default to 3131. If the 'filename' argument is given,
4709 the contents of that file will be included in the announce
4714 HTTPD-ACCELERATOR OPTIONS
4715 -----------------------------------------------------------------------------
4718 NAME: httpd_accel_surrogate_id
4721 LOC: Config.Accel.surrogate_id
4723 Surrogates (http://www.esi.org/architecture_spec_1.0.html)
4724 need an identification token to allow control targeting. Because
4725 a farm of surrogates may all perform the same tasks, they may share
4726 an identification token.
4728 The default ID is the visible_hostname
4731 NAME: http_accel_surrogate_remote
4735 LOC: Config.onoff.surrogate_is_remote
4737 Remote surrogates (such as those in a CDN) honour Surrogate-Control: no-store-remote.
4738 Set this to on to have squid behave as a remote surrogate.
4742 IFDEF: USE_SQUID_ESI
4743 COMMENT: libxml2|expat|custom
4745 LOC: ESIParser::Type
4748 ESI markup is not strictly XML compatible. The custom ESI parser
4749 will give higher performance, but cannot handle non ASCII character
4754 DELAY POOL PARAMETERS
4755 -----------------------------------------------------------------------------
4759 TYPE: delay_pool_count
4761 IFDEF: USE_DELAY_POOLS
4764 This represents the number of delay pools to be used. For example,
4765 if you have one class 2 delay pool and one class 3 delays pool, you
4766 have a total of 2 delay pools.
4770 TYPE: delay_pool_class
4772 IFDEF: USE_DELAY_POOLS
4775 This defines the class of each delay pool. There must be exactly one
4776 delay_class line for each delay pool. For example, to define two
4777 delay pools, one of class 2 and one of class 3, the settings above
4781 delay_pools 4 # 4 delay pools
4782 delay_class 1 2 # pool 1 is a class 2 pool
4783 delay_class 2 3 # pool 2 is a class 3 pool
4784 delay_class 3 4 # pool 3 is a class 4 pool
4785 delay_class 4 5 # pool 4 is a class 5 pool
4787 The delay pool classes are:
4789 class 1 Everything is limited by a single aggregate
4792 class 2 Everything is limited by a single aggregate
4793 bucket as well as an "individual" bucket chosen
4794 from bits 25 through 32 of the IPv4 address.
4796 class 3 Everything is limited by a single aggregate
4797 bucket as well as a "network" bucket chosen
4798 from bits 17 through 24 of the IP address and a
4799 "individual" bucket chosen from bits 17 through
4800 32 of the IPv4 address.
4802 class 4 Everything in a class 3 delay pool, with an
4803 additional limit on a per user basis. This
4804 only takes effect if the username is established
4805 in advance - by forcing authentication in your
4808 class 5 Requests are grouped according their tag (see
4809 external_acl's tag= reply).
4811 NOTE: If an IP address is a.b.c.d
4812 -> bits 25 through 32 are "d"
4813 -> bits 17 through 24 are "c"
4814 -> bits 17 through 32 are "c * 256 + d"
4816 NOTE-2: Due to the use of bitmasks in class 2,3,4 pools they only apply to
4817 IPv4 traffic. Class 1 and 5 pools may be used with IPv6 traffic.
4821 TYPE: delay_pool_access
4823 IFDEF: USE_DELAY_POOLS
4826 This is used to determine which delay pool a request falls into.
4828 delay_access is sorted per pool and the matching starts with pool 1,
4829 then pool 2, ..., and finally pool N. The first delay pool where the
4830 request is allowed is selected for the request. If it does not allow
4831 the request to any pool then the request is not delayed (default).
4833 For example, if you want some_big_clients in delay
4834 pool 1 and lotsa_little_clients in delay pool 2:
4837 delay_access 1 allow some_big_clients
4838 delay_access 1 deny all
4839 delay_access 2 allow lotsa_little_clients
4840 delay_access 2 deny all
4841 delay_access 3 allow authenticated_clients
4844 NAME: delay_parameters
4845 TYPE: delay_pool_rates
4847 IFDEF: USE_DELAY_POOLS
4850 This defines the parameters for a delay pool. Each delay pool has
4851 a number of "buckets" associated with it, as explained in the
4852 description of delay_class. For a class 1 delay pool, the syntax is:
4854 delay_parameters pool aggregate
4856 For a class 2 delay pool:
4858 delay_parameters pool aggregate individual
4860 For a class 3 delay pool:
4862 delay_parameters pool aggregate network individual
4864 For a class 4 delay pool:
4866 delay_parameters pool aggregate network individual user
4868 For a class 5 delay pool:
4870 delay_parameters pool tag
4872 The variables here are:
4874 pool a pool number - ie, a number between 1 and the
4875 number specified in delay_pools as used in
4878 aggregate the "delay parameters" for the aggregate bucket
4881 individual the "delay parameters" for the individual
4882 buckets (class 2, 3).
4884 network the "delay parameters" for the network buckets
4887 user the delay parameters for the user buckets
4890 tag the delay parameters for the tag buckets
4893 A pair of delay parameters is written restore/maximum, where restore is
4894 the number of bytes (not bits - modem and network speeds are usually
4895 quoted in bits) per second placed into the bucket, and maximum is the
4896 maximum number of bytes which can be in the bucket at any time.
4898 For example, if delay pool number 1 is a class 2 delay pool as in the
4899 above example, and is being used to strictly limit each host to 64kbps
4900 (plus overheads), with no overall limit, the line is:
4902 delay_parameters 1 -1/-1 8000/8000
4904 Note that the figure -1 is used to represent "unlimited".
4906 And, if delay pool number 2 is a class 3 delay pool as in the above
4907 example, and you want to limit it to a total of 256kbps (strict limit)
4908 with each 8-bit network permitted 64kbps (strict limit) and each
4909 individual host permitted 4800bps with a bucket maximum size of 64kb
4910 to permit a decent web page to be downloaded at a decent speed
4911 (if the network is not being limited due to overuse) but slow down
4912 large downloads more significantly:
4914 delay_parameters 2 32000/32000 8000/8000 600/8000
4916 There must be one delay_parameters line for each delay pool.
4918 Finally, for a class 4 delay pool as in the example - each user will
4919 be limited to 128Kb no matter how many workstations they are logged into.:
4921 delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000
4924 NAME: delay_initial_bucket_level
4925 COMMENT: (percent, 0-100)
4928 IFDEF: USE_DELAY_POOLS
4929 LOC: Config.Delay.initial
4931 The initial bucket percentage is used to determine how much is put
4932 in each bucket when squid starts, is reconfigured, or first notices
4933 a host accessing it (in class 2 and class 3, individual hosts and
4934 networks only have buckets associated with them once they have been
4939 CLIENT DELAY POOL PARAMETERS
4940 -----------------------------------------------------------------------------
4943 NAME: client_delay_pools
4944 TYPE: client_delay_pool_count
4946 IFDEF: USE_DELAY_POOLS
4947 LOC: Config.ClientDelay
4949 This option specifies the number of client delay pools used. It must
4950 preceed other client_delay_* options.
4953 client_delay_pools 2
4956 NAME: client_delay_initial_bucket_level
4957 COMMENT: (percent, 0-no_limit)
4960 IFDEF: USE_DELAY_POOLS
4961 LOC: Config.ClientDelay.initial
4963 This option determines the initial bucket size as a percentage of
4964 max_bucket_size from client_delay_parameters. Buckets are created
4965 at the time of the "first" connection from the matching IP. Idle
4966 buckets are periodically deleted up.
4968 You can specify more than 100 percent but note that such "oversized"
4969 buckets are not refilled until their size goes down to max_bucket_size
4970 from client_delay_parameters.
4973 client_delay_initial_bucket_level 50
4976 NAME: client_delay_parameters
4977 TYPE: client_delay_pool_rates
4979 IFDEF: USE_DELAY_POOLS
4980 LOC: Config.ClientDelay
4983 This option configures client-side bandwidth limits using the
4986 client_delay_parameters pool speed_limit max_bucket_size
4988 pool is an integer ID used for client_delay_access matching.
4990 speed_limit is bytes added to the bucket per second.
4992 max_bucket_size is the maximum size of a bucket, enforced after any
4993 speed_limit additions.
4995 Please see the delay_parameters option for more information and
4999 client_delay_parameters 1 1024 2048
5000 client_delay_parameters 2 51200 16384
5003 NAME: client_delay_access
5004 TYPE: client_delay_pool_access
5006 IFDEF: USE_DELAY_POOLS
5007 LOC: Config.ClientDelay
5010 This option determines the client-side delay pool for the
5013 client_delay_access pool_ID allow|deny acl_name
5015 All client_delay_access options are checked in their pool ID
5016 order, starting with pool 1. The first checked pool with allowed
5017 request is selected for the request. If no ACL matches or there
5018 are no client_delay_access options, the request bandwidth is not
5021 The ACL-selected pool is then used to find the
5022 client_delay_parameters for the request. Client-side pools are
5023 not used to aggregate clients. Clients are always aggregated
5024 based on their source IP addresses (one bucket per source IP).
5026 Please see delay_access for more examples.
5029 client_delay_access 1 allow low_rate_network
5030 client_delay_access 2 allow vips_network
5034 WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS
5035 -----------------------------------------------------------------------------
5040 LOC: Config.Wccp.router
5044 Use this option to define your WCCP ``home'' router for
5047 wccp_router supports a single WCCP(v1) router
5049 wccp2_router supports multiple WCCPv2 routers
5051 only one of the two may be used at the same time and defines
5052 which version of WCCP to use.
5056 TYPE: IpAddress_list
5057 LOC: Config.Wccp2.router
5061 Use this option to define your WCCP ``home'' router for
5064 wccp_router supports a single WCCP(v1) router
5066 wccp2_router supports multiple WCCPv2 routers
5068 only one of the two may be used at the same time and defines
5069 which version of WCCP to use.
5074 LOC: Config.Wccp.version
5078 This directive is only relevant if you need to set up WCCP(v1)
5079 to some very old and end-of-life Cisco routers. In all other
5080 setups it must be left unset or at the default setting.
5081 It defines an internal version in the WCCP(v1) protocol,
5082 with version 4 being the officially documented protocol.
5084 According to some users, Cisco IOS 11.2 and earlier only
5085 support WCCP version 3. If you're using that or an earlier
5086 version of IOS, you may need to change this value to 3, otherwise
5087 do not specify this parameter.
5090 NAME: wccp2_rebuild_wait
5092 LOC: Config.Wccp2.rebuildwait
5096 If this is enabled Squid will wait for the cache dir rebuild to finish
5097 before sending the first wccp2 HereIAm packet
5100 NAME: wccp2_forwarding_method
5102 LOC: Config.Wccp2.forwarding_method
5106 WCCP2 allows the setting of forwarding methods between the
5107 router/switch and the cache. Valid values are as follows:
5109 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
5110 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
5112 Currently (as of IOS 12.4) cisco routers only support GRE.
5113 Cisco switches only support the L2 redirect assignment method.
5116 NAME: wccp2_return_method
5118 LOC: Config.Wccp2.return_method
5122 WCCP2 allows the setting of return methods between the
5123 router/switch and the cache for packets that the cache
5124 decides not to handle. Valid values are as follows:
5126 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
5127 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
5129 Currently (as of IOS 12.4) cisco routers only support GRE.
5130 Cisco switches only support the L2 redirect assignment.
5132 If the "ip wccp redirect exclude in" command has been
5133 enabled on the cache interface, then it is still safe for
5134 the proxy server to use a l2 redirect method even if this
5135 option is set to GRE.
5138 NAME: wccp2_assignment_method
5140 LOC: Config.Wccp2.assignment_method
5144 WCCP2 allows the setting of methods to assign the WCCP hash
5145 Valid values are as follows:
5147 hash - Hash assignment
5148 mask - Mask assignment
5150 As a general rule, cisco routers support the hash assignment method
5151 and cisco switches support the mask assignment method.
5156 LOC: Config.Wccp2.info
5157 DEFAULT_IF_NONE: standard 0
5160 WCCP2 allows for multiple traffic services. There are two
5161 types: "standard" and "dynamic". The standard type defines
5162 one service id - http (id 0). The dynamic service ids can be from
5163 51 to 255 inclusive. In order to use a dynamic service id
5164 one must define the type of traffic to be redirected; this is done
5165 using the wccp2_service_info option.
5167 The "standard" type does not require a wccp2_service_info option,
5168 just specifying the service id will suffice.
5170 MD5 service authentication can be enabled by adding
5171 "password=<password>" to the end of this service declaration.
5175 wccp2_service standard 0 # for the 'web-cache' standard service
5176 wccp2_service dynamic 80 # a dynamic service type which will be
5177 # fleshed out with subsequent options.
5178 wccp2_service standard 0 password=foo
5181 NAME: wccp2_service_info
5182 TYPE: wccp2_service_info
5183 LOC: Config.Wccp2.info
5187 Dynamic WCCPv2 services require further information to define the
5188 traffic you wish to have diverted.
5192 wccp2_service_info <id> protocol=<protocol> flags=<flag>,<flag>..
5193 priority=<priority> ports=<port>,<port>..
5195 The relevant WCCPv2 flags:
5196 + src_ip_hash, dst_ip_hash
5197 + source_port_hash, dst_port_hash
5198 + src_ip_alt_hash, dst_ip_alt_hash
5199 + src_port_alt_hash, dst_port_alt_hash
5202 The port list can be one to eight entries.
5206 wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source
5207 priority=240 ports=80
5209 Note: the service id must have been defined by a previous
5210 'wccp2_service dynamic <id>' entry.
5215 LOC: Config.Wccp2.weight
5219 Each cache server gets assigned a set of the destination
5220 hash proportional to their weight.
5225 LOC: Config.Wccp.address
5232 LOC: Config.Wccp2.address
5236 Use this option if you require WCCP to use a specific
5239 The default behavior is to not bind to any specific address.
5243 PERSISTENT CONNECTION HANDLING
5244 -----------------------------------------------------------------------------
5246 Also see "pconn_timeout" in the TIMEOUTS section
5249 NAME: client_persistent_connections
5251 LOC: Config.onoff.client_pconns
5255 NAME: server_persistent_connections
5257 LOC: Config.onoff.server_pconns
5260 Persistent connection support for clients and servers. By
5261 default, Squid uses persistent connections (when allowed)
5262 with its clients and servers. You can use these options to
5263 disable persistent connections with clients and/or servers.
5266 NAME: persistent_connection_after_error
5268 LOC: Config.onoff.error_pconns
5271 With this directive the use of persistent connections after
5272 HTTP errors can be disabled. Useful if you have clients
5273 who fail to handle errors on persistent connections proper.
5276 NAME: detect_broken_pconn
5278 LOC: Config.onoff.detect_broken_server_pconns
5281 Some servers have been found to incorrectly signal the use
5282 of HTTP/1.0 persistent connections even on replies not
5283 compatible, causing significant delays. This server problem
5284 has mostly been seen on redirects.
5286 By enabling this directive Squid attempts to detect such
5287 broken replies and automatically assume the reply is finished
5288 after 10 seconds timeout.
5292 CACHE DIGEST OPTIONS
5293 -----------------------------------------------------------------------------
5296 NAME: digest_generation
5297 IFDEF: USE_CACHE_DIGESTS
5299 LOC: Config.onoff.digest_generation
5302 This controls whether the server will generate a Cache Digest
5303 of its contents. By default, Cache Digest generation is
5304 enabled if Squid is compiled with --enable-cache-digests defined.
5307 NAME: digest_bits_per_entry
5308 IFDEF: USE_CACHE_DIGESTS
5310 LOC: Config.digest.bits_per_entry
5313 This is the number of bits of the server's Cache Digest which
5314 will be associated with the Digest entry for a given HTTP
5315 Method and URL (public key) combination. The default is 5.
5318 NAME: digest_rebuild_period
5319 IFDEF: USE_CACHE_DIGESTS
5322 LOC: Config.digest.rebuild_period
5325 This is the wait time between Cache Digest rebuilds.
5328 NAME: digest_rewrite_period
5330 IFDEF: USE_CACHE_DIGESTS
5332 LOC: Config.digest.rewrite_period
5335 This is the wait time between Cache Digest writes to
5339 NAME: digest_swapout_chunk_size
5342 IFDEF: USE_CACHE_DIGESTS
5343 LOC: Config.digest.swapout_chunk_size
5346 This is the number of bytes of the Cache Digest to write to
5347 disk at a time. It defaults to 4096 bytes (4KB), the Squid
5351 NAME: digest_rebuild_chunk_percentage
5352 COMMENT: (percent, 0-100)
5353 IFDEF: USE_CACHE_DIGESTS
5355 LOC: Config.digest.rebuild_chunk_percentage
5358 This is the percentage of the Cache Digest to be scanned at a
5359 time. By default it is set to 10% of the Cache Digest.
5364 -----------------------------------------------------------------------------
5369 LOC: Config.Port.snmp
5373 The port number where Squid listens for SNMP requests. To enable
5374 SNMP support set this to a suitable port number. Port number
5375 3401 is often used for the Squid SNMP agent. By default it's
5376 set to "0" (disabled)
5384 LOC: Config.accessList.snmp
5385 DEFAULT_IF_NONE: deny all
5388 Allowing or denying access to the SNMP port.
5390 All access to the agent is denied by default.
5393 snmp_access allow|deny [!]aclname ...
5395 This clause only supports fast acl types.
5396 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5398 snmp_access allow snmppublic localhost
5399 snmp_access deny all
5402 NAME: snmp_incoming_address
5404 LOC: Config.Addrs.snmp_incoming
5409 NAME: snmp_outgoing_address
5411 LOC: Config.Addrs.snmp_outgoing
5415 Just like 'udp_incoming_address', but for the SNMP port.
5417 snmp_incoming_address is used for the SNMP socket receiving
5418 messages from SNMP agents.
5419 snmp_outgoing_address is used for SNMP packets returned to SNMP
5422 The default snmp_incoming_address is to listen on all
5423 available network interfaces.
5425 If snmp_outgoing_address is not set it will use the same socket
5426 as snmp_incoming_address. Only change this if you want to have
5427 SNMP replies sent using another address than where this Squid
5428 listens for SNMP queries.
5430 NOTE, snmp_incoming_address and snmp_outgoing_address can not have
5431 the same value since they both use port 3401.
5436 -----------------------------------------------------------------------------
5439 NAME: icp_port udp_port
5442 LOC: Config.Port.icp
5444 The port number where Squid sends and receives ICP queries to
5445 and from neighbor caches. The standard UDP port for ICP is 3130.
5446 Default is disabled (0).
5449 icp_port @DEFAULT_ICP_PORT@
5456 LOC: Config.Port.htcp
5458 The port number where Squid sends and receives HTCP queries to
5459 and from neighbor caches. To turn it on you want to set it to
5460 4827. By default it is set to "0" (disabled).
5466 NAME: log_icp_queries
5470 LOC: Config.onoff.log_udp
5472 If set, ICP queries are logged to access.log. You may wish
5473 do disable this if your ICP load is VERY high to speed things
5474 up or to simplify log analysis.
5477 NAME: udp_incoming_address
5479 LOC:Config.Addrs.udp_incoming
5482 udp_incoming_address is used for UDP packets received from other
5485 The default behavior is to not bind to any specific address.
5487 Only change this if you want to have all UDP queries received on
5488 a specific interface/address.
5490 NOTE: udp_incoming_address is used by the ICP, HTCP, and DNS
5491 modules. Altering it will affect all of them in the same manner.
5493 see also; udp_outgoing_address
5495 NOTE, udp_incoming_address and udp_outgoing_address can not
5496 have the same value since they both use the same port.
5499 NAME: udp_outgoing_address
5501 LOC: Config.Addrs.udp_outgoing
5504 udp_outgoing_address is used for UDP packets sent out to other
5507 The default behavior is to not bind to any specific address.
5509 Instead it will use the same socket as udp_incoming_address.
5510 Only change this if you want to have UDP queries sent using another
5511 address than where this Squid listens for UDP queries from other
5514 NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS
5515 modules. Altering it will affect all of them in the same manner.
5517 see also; udp_incoming_address
5519 NOTE, udp_incoming_address and udp_outgoing_address can not
5520 have the same value since they both use the same port.
5527 LOC: Config.onoff.icp_hit_stale
5529 If you want to return ICP_HIT for stale cache objects, set this
5530 option to 'on'. If you have sibling relationships with caches
5531 in other administrative domains, this should be 'off'. If you only
5532 have sibling relationships with caches under your control,
5533 it is probably okay to set this to 'on'.
5534 If set to 'on', your siblings should use the option "allow-miss"
5535 on their cache_peer lines for connecting to you.
5538 NAME: minimum_direct_hops
5541 LOC: Config.minDirectHops
5543 If using the ICMP pinging stuff, do direct fetches for sites
5544 which are no more than this many hops away.
5547 NAME: minimum_direct_rtt
5550 LOC: Config.minDirectRtt
5552 If using the ICMP pinging stuff, do direct fetches for sites
5553 which are no more than this many rtt milliseconds away.
5559 LOC: Config.Netdb.low
5565 LOC: Config.Netdb.high
5567 The low and high water marks for the ICMP measurement
5568 database. These are counts, not percents. The defaults are
5569 900 and 1000. When the high water mark is reached, database
5570 entries will be deleted until the low mark is reached.
5573 NAME: netdb_ping_period
5575 LOC: Config.Netdb.period
5578 The minimum period for measuring a site. There will be at
5579 least this much delay between successive pings to the same
5580 network. The default is five minutes.
5587 LOC: Config.onoff.query_icmp
5589 If you want to ask your peers to include ICMP data in their ICP
5590 replies, enable this option.
5592 If your peer has configured Squid (during compilation) with
5593 '--enable-icmp' that peer will send ICMP pings to origin server
5594 sites of the URLs it receives. If you enable this option the
5595 ICP replies from that peer will include the ICMP data (if available).
5596 Then, when choosing a parent cache, Squid will choose the parent with
5597 the minimal RTT to the origin server. When this happens, the
5598 hierarchy field of the access.log will be
5599 "CLOSEST_PARENT_MISS". This option is off by default.
5602 NAME: test_reachability
5606 LOC: Config.onoff.test_reachability
5608 When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
5609 instead of ICP_MISS if the target host is NOT in the ICMP
5610 database, or has a zero RTT.
5613 NAME: icp_query_timeout
5617 LOC: Config.Timeout.icp_query
5619 Normally Squid will automatically determine an optimal ICP
5620 query timeout value based on the round-trip-time of recent ICP
5621 queries. If you want to override the value determined by
5622 Squid, set this 'icp_query_timeout' to a non-zero value. This
5623 value is specified in MILLISECONDS, so, to use a 2-second
5624 timeout (the old default), you would write:
5626 icp_query_timeout 2000
5629 NAME: maximum_icp_query_timeout
5633 LOC: Config.Timeout.icp_query_max
5635 Normally the ICP query timeout is determined dynamically. But
5636 sometimes it can lead to very large values (say 5 seconds).
5637 Use this option to put an upper limit on the dynamic timeout
5638 value. Do NOT use this option to always use a fixed (instead
5639 of a dynamic) timeout value. To set a fixed timeout see the
5640 'icp_query_timeout' directive.
5643 NAME: minimum_icp_query_timeout
5647 LOC: Config.Timeout.icp_query_min
5649 Normally the ICP query timeout is determined dynamically. But
5650 sometimes it can lead to very small timeouts, even lower than
5651 the normal latency variance on your link due to traffic.
5652 Use this option to put an lower limit on the dynamic timeout
5653 value. Do NOT use this option to always use a fixed (instead
5654 of a dynamic) timeout value. To set a fixed timeout see the
5655 'icp_query_timeout' directive.
5658 NAME: background_ping_rate
5662 LOC: Config.backgroundPingRate
5664 Controls how often the ICP pings are sent to siblings that
5665 have background-ping set.
5669 MULTICAST ICP OPTIONS
5670 -----------------------------------------------------------------------------
5675 LOC: Config.mcast_group_list
5678 This tag specifies a list of multicast groups which your server
5679 should join to receive multicasted ICP queries.
5681 NOTE! Be very careful what you put here! Be sure you
5682 understand the difference between an ICP _query_ and an ICP
5683 _reply_. This option is to be set only if you want to RECEIVE
5684 multicast queries. Do NOT set this option to SEND multicast
5685 ICP (use cache_peer for that). ICP replies are always sent via
5686 unicast, so this option does not affect whether or not you will
5687 receive replies from multicast group members.
5689 You must be very careful to NOT use a multicast address which
5690 is already in use by another group of caches.
5692 If you are unsure about multicast, please read the Multicast
5693 chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
5695 Usage: mcast_groups 239.128.16.128 224.0.1.20
5697 By default, Squid doesn't listen on any multicast groups.
5700 NAME: mcast_miss_addr
5701 IFDEF: MULTICAST_MISS_STREAM
5703 LOC: Config.mcast_miss.addr
5706 If you enable this option, every "cache miss" URL will
5707 be sent out on the specified multicast address.
5709 Do not enable this option unless you are are absolutely
5710 certain you understand what you are doing.
5713 NAME: mcast_miss_ttl
5714 IFDEF: MULTICAST_MISS_STREAM
5716 LOC: Config.mcast_miss.ttl
5719 This is the time-to-live value for packets multicasted
5720 when multicasting off cache miss URLs is enabled. By
5721 default this is set to 'site scope', i.e. 16.
5724 NAME: mcast_miss_port
5725 IFDEF: MULTICAST_MISS_STREAM
5727 LOC: Config.mcast_miss.port
5730 This is the port number to be used in conjunction with
5734 NAME: mcast_miss_encode_key
5735 IFDEF: MULTICAST_MISS_STREAM
5737 LOC: Config.mcast_miss.encode_key
5738 DEFAULT: XXXXXXXXXXXXXXXX
5740 The URLs that are sent in the multicast miss stream are
5741 encrypted. This is the encryption key.
5744 NAME: mcast_icp_query_timeout
5748 LOC: Config.Timeout.mcast_icp_query
5750 For multicast peers, Squid regularly sends out ICP "probes" to
5751 count how many other peers are listening on the given multicast
5752 address. This value specifies how long Squid should wait to
5753 count all the replies. The default is 2000 msec, or 2
5758 INTERNAL ICON OPTIONS
5759 -----------------------------------------------------------------------------
5762 NAME: icon_directory
5764 LOC: Config.icons.directory
5765 DEFAULT: @DEFAULT_ICON_DIR@
5767 Where the icons are stored. These are normally kept in
5771 NAME: global_internal_static
5773 LOC: Config.onoff.global_internal_static
5776 This directive controls is Squid should intercept all requests for
5777 /squid-internal-static/ no matter which host the URL is requesting
5778 (default on setting), or if nothing special should be done for
5779 such URLs (off setting). The purpose of this directive is to make
5780 icons etc work better in complex cache hierarchies where it may
5781 not always be possible for all corners in the cache mesh to reach
5782 the server generating a directory listing.
5785 NAME: short_icon_urls
5787 LOC: Config.icons.use_short_names
5790 If this is enabled Squid will use short URLs for icons.
5791 If disabled it will revert to the old behavior of including
5792 it's own name and port in the URL.
5794 If you run a complex cache hierarchy with a mix of Squid and
5795 other proxies you may need to disable this directive.
5800 -----------------------------------------------------------------------------
5803 NAME: error_directory
5805 LOC: Config.errorDirectory
5808 If you wish to create your own versions of the default
5809 error files to customize them to suit your company copy
5810 the error/template files to another directory and point
5813 WARNING: This option will disable multi-language support
5814 on error pages if used.
5816 The squid developers are interested in making squid available in
5817 a wide variety of languages. If you are making translations for a
5818 language that Squid does not currently provide please consider
5819 contributing your translation back to the project.
5820 http://wiki.squid-cache.org/Translations
5822 The squid developers working on translations are happy to supply drop-in
5823 translated error files in exchange for any new language contributions.
5826 NAME: error_default_language
5827 IFDEF: USE_ERR_LOCALES
5829 LOC: Config.errorDefaultLanguage
5832 Set the default language which squid will send error pages in
5833 if no existing translation matches the clients language
5836 If unset (default) generic English will be used.
5838 The squid developers are interested in making squid available in
5839 a wide variety of languages. If you are interested in making
5840 translations for any language see the squid wiki for details.
5841 http://wiki.squid-cache.org/Translations
5844 NAME: error_log_languages
5845 IFDEF: USE_ERR_LOCALES
5847 LOC: Config.errorLogMissingLanguages
5850 Log to cache.log what languages users are attempting to
5851 auto-negotiate for translations.
5853 Successful negotiations are not logged. Only failures
5854 have meaning to indicate that Squid may need an upgrade
5855 of its error page translations.
5858 NAME: err_page_stylesheet
5860 LOC: Config.errorStylesheet
5861 DEFAULT: @DEFAULT_CONFIG_DIR@/errorpage.css
5863 CSS Stylesheet to pattern the display of Squid default error pages.
5865 For information on CSS see http://www.w3.org/Style/CSS/
5870 LOC: Config.errHtmlText
5873 HTML text to include in error messages. Make this a "mailto"
5874 URL to your admin address, or maybe just a link to your
5875 organizations Web page.
5877 To include this in your error messages, you must rewrite
5878 the error template files (found in the "errors" directory).
5879 Wherever you want the 'err_html_text' line to appear,
5880 insert a %L tag in the error template file.
5883 NAME: email_err_data
5886 LOC: Config.onoff.emailErrData
5889 If enabled, information about the occurred error will be
5890 included in the mailto links of the ERR pages (if %W is set)
5891 so that the email body contains the data.
5892 Syntax is <A HREF="mailto:%w%W">%w</A>
5897 LOC: Config.denyInfoList
5900 Usage: deny_info err_page_name acl
5901 or deny_info http://... acl
5902 or deny_info TCP_RESET acl
5904 This can be used to return a ERR_ page for requests which
5905 do not pass the 'http_access' rules. Squid remembers the last
5906 acl it evaluated in http_access, and if a 'deny_info' line exists
5907 for that ACL Squid returns a corresponding error page.
5909 The acl is typically the last acl on the http_access deny line which
5910 denied access. The exceptions to this rule are:
5911 - When Squid needs to request authentication credentials. It's then
5912 the first authentication related acl encountered
5913 - When none of the http_access lines matches. It's then the last
5914 acl processed on the last http_access line.
5916 NP: If providing your own custom error pages with error_directory
5917 you may also specify them by your custom file name:
5918 Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
5920 Alternatively you can tell Squid to reset the TCP connection
5921 by specifying TCP_RESET.
5923 Or you can specify an error URL or URL pattern. The browsers will
5924 get redirected (302) to the specified URL after formatting tags have
5928 %a - username (if available. Password NOT included)
5931 %E - Error description
5933 %H - Request domain name
5934 %i - Client IP Address
5936 %o - Message result from external ACL helper
5937 %p - Request Port number
5938 %P - Request Protocol name
5939 %R - Request URL path
5940 %T - Timestamp in RFC 1123 format
5941 %U - Full canonical URL from client
5942 (HTTPS URLs terminate with *)
5943 %u - Full canonical URL from client
5944 %w - Admin email from squid.conf
5945 %% - Literal percent (%) code
5950 OPTIONS INFLUENCING REQUEST FORWARDING
5951 -----------------------------------------------------------------------------
5954 NAME: nonhierarchical_direct
5956 LOC: Config.onoff.nonhierarchical_direct
5959 By default, Squid will send any non-hierarchical requests
5960 (matching hierarchy_stoplist or not cacheable request type) direct
5963 If you set this to off, Squid will prefer to send these
5964 requests to parents.
5966 Note that in most configurations, by turning this off you will only
5967 add latency to these request without any improvement in global hit
5970 If you are inside an firewall see never_direct instead of
5976 LOC: Config.onoff.prefer_direct
5979 Normally Squid tries to use parents for most requests. If you for some
5980 reason like it to first try going direct and only use a parent if
5981 going direct fails set this to on.
5983 By combining nonhierarchical_direct off and prefer_direct on you
5984 can set up Squid to use a parent as a backup path if going direct
5987 Note: If you want Squid to use parents for all requests see
5988 the never_direct directive. prefer_direct only modifies how Squid
5989 acts on cacheable requests.
5994 LOC: Config.accessList.AlwaysDirect
5997 Usage: always_direct allow|deny [!]aclname ...
5999 Here you can use ACL elements to specify requests which should
6000 ALWAYS be forwarded by Squid to the origin servers without using
6001 any peers. For example, to always directly forward requests for
6002 local servers ignoring any parents or siblings you may have use
6005 acl local-servers dstdomain my.domain.net
6006 always_direct allow local-servers
6008 To always forward FTP requests directly, use
6011 always_direct allow FTP
6013 NOTE: There is a similar, but opposite option named
6014 'never_direct'. You need to be aware that "always_direct deny
6015 foo" is NOT the same thing as "never_direct allow foo". You
6016 may need to use a deny rule to exclude a more-specific case of
6017 some other rule. Example:
6019 acl local-external dstdomain external.foo.net
6020 acl local-servers dstdomain .foo.net
6021 always_direct deny local-external
6022 always_direct allow local-servers
6024 NOTE: If your goal is to make the client forward the request
6025 directly to the origin server bypassing Squid then this needs
6026 to be done in the client configuration. Squid configuration
6027 can only tell Squid how Squid should fetch the object.
6029 NOTE: This directive is not related to caching. The replies
6030 is cached as usual even if you use always_direct. To not cache
6031 the replies see the 'cache' directive.
6033 This clause supports both fast and slow acl types.
6034 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6039 LOC: Config.accessList.NeverDirect
6042 Usage: never_direct allow|deny [!]aclname ...
6044 never_direct is the opposite of always_direct. Please read
6045 the description for always_direct if you have not already.
6047 With 'never_direct' you can use ACL elements to specify
6048 requests which should NEVER be forwarded directly to origin
6049 servers. For example, to force the use of a proxy for all
6050 requests, except those in your local domain use something like:
6052 acl local-servers dstdomain .foo.net
6053 never_direct deny local-servers
6054 never_direct allow all
6056 or if Squid is inside a firewall and there are local intranet
6057 servers inside the firewall use something like:
6059 acl local-intranet dstdomain .foo.net
6060 acl local-external dstdomain external.foo.net
6061 always_direct deny local-external
6062 always_direct allow local-intranet
6063 never_direct allow all
6065 This clause supports both fast and slow acl types.
6066 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6070 ADVANCED NETWORKING OPTIONS
6071 -----------------------------------------------------------------------------
6074 NAME: incoming_icp_average
6077 LOC: Config.comm_incoming.icp_average
6080 NAME: incoming_http_average
6083 LOC: Config.comm_incoming.http_average
6086 NAME: incoming_dns_average
6089 LOC: Config.comm_incoming.dns_average
6092 NAME: min_icp_poll_cnt
6095 LOC: Config.comm_incoming.icp_min_poll
6098 NAME: min_dns_poll_cnt
6101 LOC: Config.comm_incoming.dns_min_poll
6104 NAME: min_http_poll_cnt
6107 LOC: Config.comm_incoming.http_min_poll
6109 Heavy voodoo here. I can't even believe you are reading this.
6110 Are you crazy? Don't even think about adjusting these unless
6111 you understand the algorithms in comm_select.c first!
6117 LOC: Config.accept_filter
6121 The name of an accept(2) filter to install on Squid's
6122 listen socket(s). This feature is perhaps specific to
6123 FreeBSD and requires support in the kernel.
6125 The 'httpready' filter delays delivering new connections
6126 to Squid until a full HTTP request has been received.
6127 See the accf_http(9) man page for details.
6129 The 'dataready' filter delays delivering new connections
6130 to Squid until there is some data to process.
6131 See the accf_dataready(9) man page for details.
6135 The 'data' filter delays delivering of new connections
6136 to Squid until there is some data to process by TCP_ACCEPT_DEFER.
6137 You may optionally specify a number of seconds to wait by
6138 'data=N' where N is the number of seconds. Defaults to 30
6139 if not specified. See the tcp(7) man page for details.
6142 accept_filter httpready
6147 NAME: client_ip_max_connections
6149 LOC: Config.client_ip_max_connections
6152 Set an absolute limit on the number of connections a single
6153 client IP can use. Any more than this and Squid will begin to drop
6154 new connections from the client until it closes some links.
6156 Note that this is a global limit. It affects all HTTP, HTCP, Gopher and FTP
6157 connections from the client. For finer control use the ACL access controls.
6159 Requires client_db to be enabled (the default).
6161 WARNING: This may noticably slow down traffic received via external proxies
6162 or NAT devices and cause them to rebound error messages back to their clients.
6165 NAME: tcp_recv_bufsize
6169 LOC: Config.tcpRcvBufsz
6171 Size of receive buffer to set for TCP sockets. Probably just
6172 as easy to change your kernel's default. Set to zero to use
6173 the default buffer size.
6178 -----------------------------------------------------------------------------
6185 LOC: Adaptation::Icap::TheConfig.onoff
6188 If you want to enable the ICAP module support, set this to on.
6191 NAME: icap_connect_timeout
6194 LOC: Adaptation::Icap::TheConfig.connect_timeout_raw
6197 This parameter specifies how long to wait for the TCP connect to
6198 the requested ICAP server to complete before giving up and either
6199 terminating the HTTP transaction or bypassing the failure.
6201 The default for optional services is peer_connect_timeout.
6202 The default for essential services is connect_timeout.
6203 If this option is explicitly set, its value applies to all services.
6206 NAME: icap_io_timeout
6210 LOC: Adaptation::Icap::TheConfig.io_timeout_raw
6213 This parameter specifies how long to wait for an I/O activity on
6214 an established, active ICAP connection before giving up and
6215 either terminating the HTTP transaction or bypassing the
6218 The default is read_timeout.
6221 NAME: icap_service_failure_limit
6222 COMMENT: limit [in memory-depth time-units]
6223 TYPE: icap_service_failure_limit
6225 LOC: Adaptation::Icap::TheConfig
6228 The limit specifies the number of failures that Squid tolerates
6229 when establishing a new TCP connection with an ICAP service. If
6230 the number of failures exceeds the limit, the ICAP service is
6231 not used for new ICAP requests until it is time to refresh its
6234 A negative value disables the limit. Without the limit, an ICAP
6235 service will not be considered down due to connectivity failures
6236 between ICAP OPTIONS requests.
6238 Squid forgets ICAP service failures older than the specified
6239 value of memory-depth. The memory fading algorithm
6240 is approximate because Squid does not remember individual
6241 errors but groups them instead, splitting the option
6242 value into ten time slots of equal length.
6244 When memory-depth is 0 and by default this option has no
6245 effect on service failure expiration.
6247 Squid always forgets failures when updating service settings
6248 using an ICAP OPTIONS transaction, regardless of this option
6252 # suspend service usage after 10 failures in 5 seconds:
6253 icap_service_failure_limit 10 in 5 seconds
6256 NAME: icap_service_revival_delay
6259 LOC: Adaptation::Icap::TheConfig.service_revival_delay
6262 The delay specifies the number of seconds to wait after an ICAP
6263 OPTIONS request failure before requesting the options again. The
6264 failed ICAP service is considered "down" until fresh OPTIONS are
6267 The actual delay cannot be smaller than the hardcoded minimum
6268 delay of 30 seconds.
6271 NAME: icap_preview_enable
6275 LOC: Adaptation::Icap::TheConfig.preview_enable
6278 The ICAP Preview feature allows the ICAP server to handle the
6279 HTTP message by looking only at the beginning of the message body
6280 or even without receiving the body at all. In some environments,
6281 previews greatly speedup ICAP processing.
6283 During an ICAP OPTIONS transaction, the server may tell Squid what
6284 HTTP messages should be previewed and how big the preview should be.
6285 Squid will not use Preview if the server did not request one.
6287 To disable ICAP Preview for all ICAP services, regardless of
6288 individual ICAP server OPTIONS responses, set this option to "off".
6290 icap_preview_enable off
6293 NAME: icap_preview_size
6296 LOC: Adaptation::Icap::TheConfig.preview_size
6299 The default size of preview data to be sent to the ICAP server.
6300 -1 means no preview. This value might be overwritten on a per server
6301 basis by OPTIONS requests.
6304 NAME: icap_206_enable
6308 LOC: Adaptation::Icap::TheConfig.allow206_enable
6311 206 (Partial Content) responses is an ICAP extension that allows the
6312 ICAP agents to optionally combine adapted and original HTTP message
6313 content. The decision to combine is postponed until the end of the
6314 ICAP response. Squid supports Partial Content extension by default.
6316 Activation of the Partial Content extension is negotiated with each
6317 ICAP service during OPTIONS exchange. Most ICAP servers should handle
6318 negotation correctly even if they do not support the extension, but
6319 some might fail. To disable Partial Content support for all ICAP
6320 services and to avoid any negotiation, set this option to "off".
6326 NAME: icap_default_options_ttl
6329 LOC: Adaptation::Icap::TheConfig.default_options_ttl
6332 The default TTL value for ICAP OPTIONS responses that don't have
6333 an Options-TTL header.
6336 NAME: icap_persistent_connections
6340 LOC: Adaptation::Icap::TheConfig.reuse_connections
6343 Whether or not Squid should use persistent connections to
6347 NAME: icap_send_client_ip
6351 LOC: Adaptation::Icap::TheConfig.send_client_ip
6354 This adds the header "X-Client-IP" to ICAP requests.
6357 NAME: icap_send_client_username
6361 LOC: Adaptation::Icap::TheConfig.send_client_username
6364 This sends authenticated HTTP client username (if available) to
6365 the ICAP service. The username value is encoded based on the
6366 icap_client_username_encode option and is sent using the header
6367 specified by the icap_client_username_header option.
6370 NAME: icap_client_username_header
6373 LOC: Adaptation::Icap::TheConfig.client_username_header
6374 DEFAULT: X-Client-Username
6376 ICAP request header name to use for send_client_username.
6379 NAME: icap_client_username_encode
6383 LOC: Adaptation::Icap::TheConfig.client_username_encode
6386 Whether to base64 encode the authenticated client username.
6390 TYPE: icap_service_type
6392 LOC: Adaptation::Icap::TheConfig
6395 Defines a single ICAP service using the following format:
6397 icap_service service_name vectoring_point [options] service_url
6400 an opaque identifier which must be unique in squid.conf
6402 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
6403 This specifies at which point of transaction processing the
6404 ICAP service should be activated. *_postcache vectoring points
6405 are not yet supported.
6407 service_url: icap://servername:port/servicepath
6408 ICAP server and service location.
6410 ICAP does not allow a single service to handle both REQMOD and RESPMOD
6411 transactions. Squid does not enforce that requirement. You can specify
6412 services with the same service_url and different vectoring_points. You
6413 can even specify multiple identical services as long as their
6414 service_names differ.
6417 Service options are separated by white space. ICAP services support
6418 the following name=value options:
6421 If set to 'on' or '1', the ICAP service is treated as
6422 optional. If the service cannot be reached or malfunctions,
6423 Squid will try to ignore any errors and process the message as
6424 if the service was not enabled. No all ICAP errors can be
6425 bypassed. If set to 0, the ICAP service is treated as
6426 essential and all ICAP errors will result in an error page
6427 returned to the HTTP client.
6429 Bypass is off by default: services are treated as essential.
6432 If set to 'on' or '1', the ICAP service is allowed to
6433 dynamically change the current message adaptation plan by
6434 returning a chain of services to be used next. The services
6435 are specified using the X-Next-Services ICAP response header
6436 value, formatted as a comma-separated list of service names.
6437 Each named service should be configured in squid.conf and
6438 should have the same method and vectoring point as the current
6439 ICAP transaction. Services violating these rules are ignored.
6440 An empty X-Next-Services value results in an empty plan which
6441 ends the current adaptation.
6443 Routing is not allowed by default: the ICAP X-Next-Services
6444 response header is ignored.
6447 Only has effect on split-stack systems. The default on those systems
6448 is to use IPv4-only connections. When set to 'on' this option will
6449 make Squid use IPv6-only connections to contact this ICAP service.
6451 Older icap_service format without optional named parameters is
6452 deprecated but supported for backward compatibility.
6455 icap_service svcBlocker reqmod_precache bypass=0 icap://icap1.mydomain.net:1344/reqmod
6456 icap_service svcLogger reqmod_precache routing=on icap://icap2.mydomain.net:1344/respmod
6460 TYPE: icap_class_type
6465 This deprecated option was documented to define an ICAP service
6466 chain, even though it actually defined a set of similar, redundant
6467 services, and the chains were not supported.
6469 To define a set of redundant services, please use the
6470 adaptation_service_set directive. For service chains, use
6471 adaptation_service_chain.
6475 TYPE: icap_access_type
6480 This option is deprecated. Please use adaptation_access, which
6481 has the same ICAP functionality, but comes with better
6482 documentation, and eCAP support.
6487 -----------------------------------------------------------------------------
6494 LOC: Adaptation::Ecap::TheConfig.onoff
6497 Controls whether eCAP support is enabled.
6501 TYPE: ecap_service_type
6503 LOC: Adaptation::Ecap::TheConfig
6506 Defines a single eCAP service
6508 ecap_service servicename vectoring_point bypass service_url
6510 vectoring_point = reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
6511 This specifies at which point of transaction processing the
6512 eCAP service should be activated. *_postcache vectoring points
6513 are not yet supported.
6515 If set to 1, the eCAP service is treated as optional. If the
6516 service cannot be reached or malfunctions, Squid will try to
6517 ignore any errors and process the message as if the service
6518 was not enabled. No all eCAP errors can be bypassed.
6519 If set to 0, the eCAP service is treated as essential and all
6520 eCAP errors will result in an error page returned to the
6522 service_url = ecap://vendor/service_name?custom&cgi=style¶meters=optional
6525 ecap_service service_1 reqmod_precache 0 ecap://filters-R-us/leakDetector?on_error=block
6526 ecap_service service_2 respmod_precache 1 icap://filters-R-us/virusFilter?config=/etc/vf.cfg
6529 NAME: loadable_modules
6531 IFDEF: USE_LOADABLE_MODULES
6532 LOC: Config.loadable_module_names
6535 Instructs Squid to load the specified dynamic module(s) or activate
6536 preloaded module(s).
6538 loadable_modules @DEFAULT_PREFIX@/lib/MinimalAdapter.so
6542 MESSAGE ADAPTATION OPTIONS
6543 -----------------------------------------------------------------------------
6546 NAME: adaptation_service_set
6547 TYPE: adaptation_service_set_type
6548 IFDEF: USE_ADAPTATION
6553 Configures an ordered set of similar, redundant services. This is
6554 useful when hot standby or backup adaptation servers are available.
6556 adaptation_service_set set_name service_name1 service_name2 ...
6558 The named services are used in the set declaration order. The first
6559 applicable adaptation service from the set is used first. The next
6560 applicable service is tried if and only if the transaction with the
6561 previous service fails and the message waiting to be adapted is still
6564 When adaptation starts, broken services are ignored as if they were
6565 not a part of the set. A broken service is a down optional service.
6567 The services in a set must be attached to the same vectoring point
6568 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
6570 If all services in a set are optional then adaptation failures are
6571 bypassable. If all services in the set are essential, then a
6572 transaction failure with one service may still be retried using
6573 another service from the set, but when all services fail, the master
6574 transaction fails as well.
6576 A set may contain a mix of optional and essential services, but that
6577 is likely to lead to surprising results because broken services become
6578 ignored (see above), making previously bypassable failures fatal.
6579 Technically, it is the bypassability of the last failed service that
6582 See also: adaptation_access adaptation_service_chain
6585 adaptation_service_set svcBlocker urlFilterPrimary urlFilterBackup
6586 adaptation service_set svcLogger loggerLocal loggerRemote
6589 NAME: adaptation_service_chain
6590 TYPE: adaptation_service_chain_type
6591 IFDEF: USE_ADAPTATION
6596 Configures a list of complementary services that will be applied
6597 one-by-one, forming an adaptation chain or pipeline. This is useful
6598 when Squid must perform different adaptations on the same message.
6600 adaptation_service_chain chain_name service_name1 svc_name2 ...
6602 The named services are used in the chain declaration order. The first
6603 applicable adaptation service from the chain is used first. The next
6604 applicable service is applied to the successful adaptation results of
6605 the previous service in the chain.
6607 When adaptation starts, broken services are ignored as if they were
6608 not a part of the chain. A broken service is a down optional service.
6610 Request satisfaction terminates the adaptation chain because Squid
6611 does not currently allow declaration of RESPMOD services at the
6612 "reqmod_precache" vectoring point (see icap_service or ecap_service).
6614 The services in a chain must be attached to the same vectoring point
6615 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
6617 A chain may contain a mix of optional and essential services. If an
6618 essential adaptation fails (or the failure cannot be bypassed for
6619 other reasons), the master transaction fails. Otherwise, the failure
6620 is bypassed as if the failed adaptation service was not in the chain.
6622 See also: adaptation_access adaptation_service_set
6625 adaptation_service_chain svcRequest requestLogger urlFilter leakDetector
6628 NAME: adaptation_access
6629 TYPE: adaptation_access_type
6630 IFDEF: USE_ADAPTATION
6634 Sends an HTTP transaction to an ICAP or eCAP adaptation service.
6636 adaptation_access service_name allow|deny [!]aclname...
6637 adaptation_access set_name allow|deny [!]aclname...
6639 At each supported vectoring point, the adaptation_access
6640 statements are processed in the order they appear in this
6641 configuration file. Statements pointing to the following services
6642 are ignored (i.e., skipped without checking their ACL):
6644 - services serving different vectoring points
6645 - "broken-but-bypassable" services
6646 - "up" services configured to ignore such transactions
6647 (e.g., based on the ICAP Transfer-Ignore header).
6649 When a set_name is used, all services in the set are checked
6650 using the same rules, to find the first applicable one. See
6651 adaptation_service_set for details.
6653 If an access list is checked and there is a match, the
6654 processing stops: For an "allow" rule, the corresponding
6655 adaptation service is used for the transaction. For a "deny"
6656 rule, no adaptation service is activated.
6658 It is currently not possible to apply more than one adaptation
6659 service at the same vectoring point to the same HTTP transaction.
6661 See also: icap_service and ecap_service
6664 adaptation_access service_1 allow all
6667 NAME: adaptation_service_iteration_limit
6669 IFDEF: USE_ADAPTATION
6670 LOC: Adaptation::Config::service_iteration_limit
6673 Limits the number of iterations allowed when applying adaptation
6674 services to a message. If your longest adaptation set or chain
6675 may have more than 16 services, increase the limit beyond its
6676 default value of 16. If detecting infinite iteration loops sooner
6677 is critical, make the iteration limit match the actual number
6678 of services in your longest adaptation set or chain.
6680 Infinite adaptation loops are most likely with routing services.
6682 See also: icap_service routing=1
6685 NAME: adaptation_masterx_shared_names
6687 IFDEF: USE_ADAPTATION
6688 LOC: Adaptation::Config::masterx_shared_name
6691 For each master transaction (i.e., the HTTP request and response
6692 sequence, including all related ICAP and eCAP exchanges), Squid
6693 maintains a table of metadata. The table entries are (name, value)
6694 pairs shared among eCAP and ICAP exchanges. The table is destroyed
6695 with the master transaction.
6697 This option specifies the table entry names that Squid must accept
6698 from and forward to the adaptation transactions.
6700 An ICAP REQMOD or RESPMOD transaction may set an entry in the
6701 shared table by returning an ICAP header field with a name
6702 specified in adaptation_masterx_shared_names. Squid will store
6703 and forward that ICAP header field to subsequent ICAP
6704 transactions within the same master transaction scope.
6706 Only one shared entry name is supported at this time.
6709 # share authentication information among ICAP services
6710 adaptation_masterx_shared_names X-Subscriber-ID
6716 LOC: Adaptation::Icap::TheConfig.repeat
6717 DEFAULT_IF_NONE: deny all
6719 This ACL determines which retriable ICAP transactions are
6720 retried. Transactions that received a complete ICAP response
6721 and did not have to consume or produce HTTP bodies to receive
6722 that response are usually retriable.
6724 icap_retry allow|deny [!]aclname ...
6726 Squid automatically retries some ICAP I/O timeouts and errors
6727 due to persistent connection race conditions.
6729 See also: icap_retry_limit
6732 NAME: icap_retry_limit
6735 LOC: Adaptation::Icap::TheConfig.repeat_limit
6738 Limits the number of retries allowed. When set to zero (default),
6739 no retries are allowed.
6741 Communication errors due to persistent connection race
6742 conditions are unavoidable, automatically retried, and do not
6743 count against this limit.
6745 See also: icap_retry
6751 -----------------------------------------------------------------------------
6754 NAME: check_hostnames
6757 LOC: Config.onoff.check_hostnames
6759 For security and stability reasons Squid can check
6760 hostnames for Internet standard RFC compliance. If you want
6761 Squid to perform these checks turn this directive on.
6764 NAME: allow_underscore
6767 LOC: Config.onoff.allow_underscore
6769 Underscore characters is not strictly allowed in Internet hostnames
6770 but nevertheless used by many sites. Set this to off if you want
6771 Squid to be strict about the standard.
6772 This check is performed only when check_hostnames is set to on.
6775 NAME: cache_dns_program
6777 IFDEF: USE_DNSSERVERS
6778 DEFAULT: @DEFAULT_DNSSERVER@
6779 LOC: Config.Program.dnsserver
6781 Specify the location of the executable for dnslookup process.
6785 TYPE: HelperChildConfig
6786 IFDEF: USE_DNSSERVERS
6787 DEFAULT: 32 startup=1 idle=1
6788 LOC: Config.dnsChildren
6790 The maximum number of processes spawn to service DNS name lookups.
6791 If you limit it too few Squid will have to wait for them to process
6792 a backlog of requests, slowing it down. If you allow too many they
6793 will use RAM and other system resources noticably.
6794 The maximum this may be safely set to is 32.
6796 The startup= and idle= options allow some measure of skew in your
6801 Sets a minimum of how many processes are to be spawned when Squid
6802 starts or reconfigures. When set to zero the first request will
6803 cause spawning of the first child process to handle it.
6805 Starting too few will cause an initial slowdown in traffic as Squid
6806 attempts to simultaneously spawn enough processes to cope.
6810 Sets a minimum of how many processes Squid is to try and keep available
6811 at all times. When traffic begins to rise above what the existing
6812 processes can handle this many more will be spawned up to the maximum
6813 configured. A minimum setting of 1 is required.
6816 NAME: dns_retransmit_interval
6819 LOC: Config.Timeout.idns_retransmit
6820 IFDEF: !USE_DNSSERVERS
6822 Initial retransmit interval for DNS queries. The interval is
6823 doubled each time all configured DNS servers have been tried.
6829 LOC: Config.Timeout.idns_query
6830 IFDEF: !USE_DNSSERVERS
6832 DNS Query timeout. If no response is received to a DNS query
6833 within this time all DNS servers for the queried domain
6834 are assumed to be unavailable.
6837 NAME: dns_packet_max
6840 LOC: Config.dns.packet_max
6841 IFDEF: !USE_DNSSERVERS
6843 Maximum number of bytes packet size to advertise via EDNS.
6844 Set to "none" to disable EDNS large packet support.
6846 For legacy reasons DNS UDP replies will default to 512 bytes which
6847 is too small for many responses. EDNS provides a means for Squid to
6848 negotiate receiving larger responses back immediately without having
6849 to failover with repeat requests. Responses larger than this limit
6850 will retain the old behaviour of failover to TCP DNS.
6852 Squid has no real fixed limit internally, but allowing packet sizes
6853 over 1500 bytes requires network jumbogram support and is usually not
6856 WARNING: The RFC also indicates that some older resolvers will reply
6857 with failure of the whole request if the extension is added. Some
6858 resolvers have already been identified which will reply with mangled
6859 EDNS response on occasion. Usually in response to many-KB jumbogram
6860 sizes being advertised by Squid.
6861 Squid will currently treat these both as an unable-to-resolve domain
6862 even if it would be resolvable without EDNS.
6869 LOC: Config.onoff.res_defnames
6871 Normally the RES_DEFNAMES resolver option is disabled
6872 (see res_init(3)). This prevents caches in a hierarchy
6873 from interpreting single-component hostnames locally. To allow
6874 Squid to handle single-component names, enable this option.
6877 NAME: dns_nameservers
6880 LOC: Config.dns_nameservers
6882 Use this if you want to specify a list of DNS name servers
6883 (IP addresses) to use instead of those given in your
6884 /etc/resolv.conf file.
6885 On Windows platforms, if no value is specified here or in
6886 the /etc/resolv.conf file, the list of DNS name servers are
6887 taken from the Windows registry, both static and dynamic DHCP
6888 configurations are supported.
6890 Example: dns_nameservers 10.0.0.1 192.172.0.4
6895 DEFAULT: @DEFAULT_HOSTS@
6896 LOC: Config.etcHostsPath
6898 Location of the host-local IP name-address associations
6899 database. Most Operating Systems have such a file on different
6901 - Un*X & Linux: /etc/hosts
6902 - Windows NT/2000: %SystemRoot%\system32\drivers\etc\hosts
6903 (%SystemRoot% value install default is c:\winnt)
6904 - Windows XP/2003: %SystemRoot%\system32\drivers\etc\hosts
6905 (%SystemRoot% value install default is c:\windows)
6906 - Windows 9x/Me: %windir%\hosts
6907 (%windir% value is usually c:\windows)
6908 - Cygwin: /etc/hosts
6910 The file contains newline-separated definitions, in the
6911 form ip_address_in_dotted_form name [name ...] names are
6912 whitespace-separated. Lines beginning with an hash (#)
6913 character are comments.
6915 The file is checked at startup and upon configuration.
6916 If set to 'none', it won't be checked.
6917 If append_domain is used, that domain will be added to
6918 domain-local (i.e. not containing any dot character) host
6924 LOC: Config.appendDomain
6927 Appends local domain name to hostnames without any dots in
6928 them. append_domain must begin with a period.
6930 Be warned there are now Internet names with no dots in
6931 them using only top-domain names, so setting this may
6932 cause some Internet sites to become unavailable.
6935 append_domain .yourdomain.com
6938 NAME: ignore_unknown_nameservers
6940 LOC: Config.onoff.ignore_unknown_nameservers
6943 By default Squid checks that DNS responses are received
6944 from the same IP addresses they are sent to. If they
6945 don't match, Squid ignores the response and writes a warning
6946 message to cache.log. You can allow responses from unknown
6947 nameservers by setting this option to 'off'.
6950 NAME: dns_v4_fallback
6953 LOC: Config.onoff.dns_require_A
6955 Standard practice with DNS is to lookup either A or AAAA records
6956 and use the results if it succeeds. Only looking up the other if
6957 the first attempt fails or otherwise produces no results.
6959 That policy however will cause squid to produce error pages for some
6960 servers that advertise AAAA but are unreachable over IPv6.
6962 If this is ON squid will always lookup both AAAA and A, using both.
6963 If this is OFF squid will lookup AAAA and only try A if none found.
6965 WARNING: There are some possibly unwanted side-effects with this on:
6966 *) Doubles the load placed by squid on the DNS network.
6967 *) May negatively impact connection delay times.
6971 COMMENT: (number of entries)
6974 LOC: Config.ipcache.size
6981 LOC: Config.ipcache.low
6988 LOC: Config.ipcache.high
6990 The size, low-, and high-water marks for the IP cache.
6993 NAME: fqdncache_size
6994 COMMENT: (number of entries)
6997 LOC: Config.fqdncache.size
6999 Maximum number of FQDN cache entries.
7004 -----------------------------------------------------------------------------
7011 LOC: Config.onoff.mem_pools
7013 If set, Squid will keep pools of allocated (but unused) memory
7014 available for future use. If memory is a premium on your
7015 system and you believe your malloc library outperforms Squid
7016 routines, disable this.
7019 NAME: memory_pools_limit
7023 LOC: Config.MemPools.limit
7025 Used only with memory_pools on:
7026 memory_pools_limit 50 MB
7028 If set to a non-zero value, Squid will keep at most the specified
7029 limit of allocated (but unused) memory in memory pools. All free()
7030 requests that exceed this limit will be handled by your malloc
7031 library. Squid does not pre-allocate any memory, just safe-keeps
7032 objects that otherwise would be free()d. Thus, it is safe to set
7033 memory_pools_limit to a reasonably high value even if your
7034 configuration will use less memory.
7036 If set to none, Squid will keep all memory it can. That is, there
7037 will be no limit on the total amount of memory used for safe-keeping.
7039 To disable memory allocation optimization, do not set
7040 memory_pools_limit to 0 or none. Set memory_pools to "off" instead.
7042 An overhead for maintaining memory pools is not taken into account
7043 when the limit is checked. This overhead is close to four bytes per
7044 object kept. However, pools may actually _save_ memory because of
7045 reduced memory thrashing in your malloc library.
7049 COMMENT: on|off|transparent|truncate|delete
7052 LOC: opt_forwarded_for
7054 If set to "on", Squid will append your client's IP address
7055 in the HTTP requests it forwards. By default it looks like:
7057 X-Forwarded-For: 192.1.2.3
7059 If set to "off", it will appear as
7061 X-Forwarded-For: unknown
7063 If set to "transparent", Squid will not alter the
7064 X-Forwarded-For header in any way.
7066 If set to "delete", Squid will delete the entire
7067 X-Forwarded-For header.
7069 If set to "truncate", Squid will remove all existing
7070 X-Forwarded-For entries, and place itself as the sole entry.
7073 NAME: cachemgr_passwd
7074 TYPE: cachemgrpasswd
7076 LOC: Config.passwd_list
7078 Specify passwords for cachemgr operations.
7080 Usage: cachemgr_passwd password action action ...
7082 Some valid actions are (see cache manager menu for a full list):
7122 * Indicates actions which will not be performed without a
7123 valid password, others can be performed if not listed here.
7125 To disable an action, set the password to "disable".
7126 To allow performing an action without a password, set the
7129 Use the keyword "all" to set the same password for all actions.
7132 cachemgr_passwd secret shutdown
7133 cachemgr_passwd lesssssssecret info stats/objects
7134 cachemgr_passwd disable all
7141 LOC: Config.onoff.client_db
7143 If you want to disable collecting per-client statistics,
7144 turn off client_db here.
7147 NAME: refresh_all_ims
7151 LOC: Config.onoff.refresh_all_ims
7153 When you enable this option, squid will always check
7154 the origin server for an update when a client sends an
7155 If-Modified-Since request. Many browsers use IMS
7156 requests when the user requests a reload, and this
7157 ensures those clients receive the latest version.
7159 By default (off), squid may return a Not Modified response
7160 based on the age of the cached version.
7163 NAME: reload_into_ims
7164 IFDEF: USE_HTTP_VIOLATIONS
7168 LOC: Config.onoff.reload_into_ims
7170 When you enable this option, client no-cache or ``reload''
7171 requests will be changed to If-Modified-Since requests.
7172 Doing this VIOLATES the HTTP standard. Enabling this
7173 feature could make you liable for problems which it
7176 see also refresh_pattern for a more selective approach.
7179 NAME: maximum_single_addr_tries
7181 LOC: Config.retry.maxtries
7184 This sets the maximum number of connection attempts for a
7185 host that only has one address (for multiple-address hosts,
7186 each address is tried once).
7188 The default value is one attempt, the (not recommended)
7189 maximum is 255 tries. A warning message will be generated
7190 if it is set to a value greater than ten.
7192 Note: This is in addition to the request re-forwarding which
7193 takes place if Squid fails to get a satisfying response.
7196 NAME: retry_on_error
7198 LOC: Config.retry.onerror
7201 If set to on Squid will automatically retry requests when
7202 receiving an error response. This is mainly useful if you
7203 are in a complex cache hierarchy to work around access
7207 NAME: as_whois_server
7209 LOC: Config.as_whois_server
7210 DEFAULT: whois.ra.net
7212 WHOIS server to query for AS numbers. NOTE: AS numbers are
7213 queried only when Squid starts up, not for every request.
7218 LOC: Config.onoff.offline
7221 Enable this option and Squid will never try to validate cached
7225 NAME: uri_whitespace
7226 TYPE: uri_whitespace
7227 LOC: Config.uri_whitespace
7230 What to do with requests that have whitespace characters in the
7233 strip: The whitespace characters are stripped out of the URL.
7234 This is the behavior recommended by RFC2396.
7235 deny: The request is denied. The user receives an "Invalid
7237 allow: The request is allowed and the URI is not changed. The
7238 whitespace characters remain in the URI. Note the
7239 whitespace is passed to redirector processes if they
7241 encode: The request is allowed and the whitespace characters are
7242 encoded according to RFC1738. This could be considered
7243 a violation of the HTTP/1.1
7244 RFC because proxies are not allowed to rewrite URI's.
7245 chop: The request is allowed and the URI is chopped at the
7246 first whitespace. This might also be considered a
7252 LOC: Config.chroot_dir
7255 Specifies a directory where Squid should do a chroot() while
7256 initializing. This also causes Squid to fully drop root
7257 privileges after initializing. This means, for example, if you
7258 use a HTTP port less than 1024 and try to reconfigure, you may
7259 get an error saying that Squid can not open the port.
7262 NAME: balance_on_multiple_ip
7264 LOC: Config.onoff.balance_on_multiple_ip
7267 Modern IP resolvers in squid sort lookup results by preferred access.
7268 By default squid will use these IP in order and only rotates to
7269 the next listed when the most preffered fails.
7271 Some load balancing servers based on round robin DNS have been
7272 found not to preserve user session state across requests
7273 to different IP addresses.
7275 Enabling this directive Squid rotates IP's per request.
7278 NAME: pipeline_prefetch
7280 LOC: Config.onoff.pipeline_prefetch
7283 To boost the performance of pipelined requests to closer
7284 match that of a non-proxied environment Squid can try to fetch
7285 up to two requests in parallel from a pipeline.
7287 Defaults to off for bandwidth management and access logging
7291 NAME: high_response_time_warning
7294 LOC: Config.warnings.high_rptm
7297 If the one-minute median response time exceeds this value,
7298 Squid prints a WARNING with debug level 0 to get the
7299 administrators attention. The value is in milliseconds.
7302 NAME: high_page_fault_warning
7304 LOC: Config.warnings.high_pf
7307 If the one-minute average page fault rate exceeds this
7308 value, Squid prints a WARNING with debug level 0 to get
7309 the administrators attention. The value is in page faults
7313 NAME: high_memory_warning
7315 LOC: Config.warnings.high_memory
7318 If the memory usage (as determined by mallinfo) exceeds
7319 this amount, Squid prints a WARNING with debug level 0 to get
7320 the administrators attention.
7323 NAME: sleep_after_fork
7324 COMMENT: (microseconds)
7326 LOC: Config.sleep_after_fork
7329 When this is set to a non-zero value, the main Squid process
7330 sleeps the specified number of microseconds after a fork()
7331 system call. This sleep may help the situation where your
7332 system reports fork() failures due to lack of (virtual)
7333 memory. Note, however, if you have a lot of child
7334 processes, these sleep delays will add up and your
7335 Squid will not service requests for some amount of time
7336 until all the child processes have been started.
7337 On Windows value less then 1000 (1 milliseconds) are
7341 NAME: windows_ipaddrchangemonitor
7342 IFDEF: _SQUID_MSWIN_
7346 LOC: Config.onoff.WIN32_IpAddrChangeMonitor
7348 On Windows Squid by default will monitor IP address changes and will
7349 reconfigure itself after any detected event. This is very useful for
7350 proxies connected to internet with dial-up interfaces.
7351 In some cases (a Proxy server acting as VPN gateway is one) it could be
7352 desiderable to disable this behaviour setting this to 'off'.
7353 Note: after changing this, Squid service must be restarted.
7358 IFDEF: USE_SQUID_EUI
7360 LOC: Eui::TheConfig.euiLookup
7362 Whether to lookup the EUI or MAC address of a connected client.
7365 NAME: max_filedescriptors max_filedesc
7368 LOC: Config.max_filedescriptors
7370 The maximum number of filedescriptors supported.
7372 The default "0" means Squid inherits the current ulimit setting.
7374 Note: Changing this requires a restart of Squid. Also
7375 not all comm loops supports large values.
7383 Number of main Squid processes or "workers" to fork and maintain.
7384 0: "no daemon" mode, like running "squid -N ..."
7385 1: "no SMP" mode, start one main Squid process daemon (default)
7386 N: start N main Squid process daemons (i.e., SMP mode)
7388 In SMP mode, each worker does nearly all what a single Squid daemon
7389 does (e.g., listen on http_port and forward HTTP requests).
7392 NAME: cpu_affinity_map
7393 TYPE: CpuAffinityMap
7394 LOC: Config.cpuAffinityMap
7397 Usage: cpu_affinity_map process_numbers=P1,P2,... cores=C1,C2,...
7399 Sets 1:1 mapping between Squid processes and CPU cores. For example,
7401 cpu_affinity_map process_numbers=1,2,3,4 cores=1,3,5,7
7403 affects processes 1 through 4 only and places them on the first
7404 four even cores, starting with core #1.
7406 CPU cores are numbered starting from 1. Requires support for
7407 sched_getaffinity(2) and sched_setaffinity(2) system calls.
7409 Multiple cpu_affinity_map options are merged.