2 # SQUID Web Proxy Cache http://www.squid-cache.org/
3 # ----------------------------------------------------------
5 # Squid is the result of efforts by numerous individuals from
6 # the Internet community; see the CONTRIBUTORS file for full
7 # details. Many organizations have provided support for Squid's
8 # development; see the SPONSORS file for full details. Squid is
9 # Copyrighted (C) 2000 by the Regents of the University of
10 # California; see the COPYRIGHT file for full details. Squid
11 # incorporates software developed and/or copyrighted by other
12 # sources; see the CREDITS file for full details.
14 # This program is free software; you can redistribute it and/or modify
15 # it under the terms of the GNU General Public License as published by
16 # the Free Software Foundation; either version 2 of the License, or
17 # (at your option) any later version.
19 # This program is distributed in the hope that it will be useful,
20 # but WITHOUT ANY WARRANTY; without even the implied warranty of
21 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 # GNU General Public License for more details.
24 # You should have received a copy of the GNU General Public License
25 # along with this program; if not, write to the Free Software
26 # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
31 ----------------------------
33 This is the default Squid configuration file. You may wish
34 to look at the Squid home page (http://www.squid-cache.org/)
35 for the FAQ and other documentation.
37 The default Squid config file shows what the defaults for
38 various options happen to be. If you don't need to change the
39 default, you shouldn't uncomment the line. Doing so may cause
40 run-time problems. In some cases "none" refers to no default
41 setting at all, while in other cases it refers to a valid
42 option - the comments for that keyword indicate if this is the
48 Configuration options can be included using the "include" directive.
49 Include takes a list of files to include. Quoting and wildcards is
54 include /path/to/included/file/squid.acl.config
56 Includes can be nested up to a hard-coded depth of 16 levels.
57 This arbitrary restriction is to prevent recursive include references
58 from causing Squid entering an infinite loop whilst trying to load
62 Conditional configuration
64 If-statements can be used to make configuration directives
68 ... regular configuration directives ...
70 ... regular configuration directives ...]
73 The else part is optional. The keywords "if", "else", and "endif"
74 must be typed on their own lines, as if they were regular
75 configuration directives.
77 These individual conditions types are supported:
80 Always evaluates to true.
82 Always evaluates to false.
84 Equality comparison of two integer numbers.
89 The following SMP-related preprocessor macros can be used.
91 ${process_name} expands to the current Squid process "name"
92 (e.g., squid1, squid2, or cache1).
94 ${process_number} expands to the current Squid process
95 identifier, which is an integer number (e.g., 1, 2, 3) unique
96 across all Squid processes.
99 # Options Removed in 3.2
100 NAME: ignore_expect_100
103 Remove this line. The HTTP/1.1 feature is now fully supported by default.
109 Remove this line. Configure FTP page display using the CSS controls in errorpages.css instead.
112 NAME: url_rewrite_concurrency
115 Remove this line. Set the 'concurrency=' option of url_rewrite_children instead.
118 # Options Removed in 3.1
122 Remove this line. DNS is no longer tested on startup.
125 NAME: extension_methods
128 Remove this line. All valid methods for HTTP are accepted by default.
131 # 2.7 Options Removed/Replaced in 3.1
139 Remove this line. HTTP/1.1 is supported by default.
142 NAME: upgrade_http0.9
145 Remove this line. ICY/1.0 streaming protocol is supported by default.
148 NAME: zph_local zph_mode zph_option zph_parent zph_sibling
151 Alter these entries. Use the qos_flows directive instead.
154 # Options Removed in 3.0
158 Since squid-3.0 replace with request_header_access or reply_header_access
159 depending on whether you wish to match client requests or server replies.
162 NAME: httpd_accel_no_pmtu_disc
165 Since squid-3.0 use the 'disable-pmtu-discovery' flag on http_port instead.
169 OPTIONS FOR AUTHENTICATION
170 -----------------------------------------------------------------------------
178 This is used to define parameters for the various authentication
179 schemes supported by Squid.
181 format: auth_param scheme parameter [setting]
183 The order in which authentication schemes are presented to the client is
184 dependent on the order the scheme first appears in config file. IE
185 has a bug (it's not RFC 2617 compliant) in that it will use the basic
186 scheme if basic is the first entry presented, even if more secure
187 schemes are presented. For now use the order in the recommended
188 settings section below. If other browsers have difficulties (don't
189 recognize the schemes offered even if you are using basic) either
190 put basic first, or disable the other schemes (by commenting out their
193 Once an authentication scheme is fully configured, it can only be
194 shutdown by shutting squid down and restarting. Changes can be made on
195 the fly and activated with a reconfigure. I.E. You can change to a
196 different helper, but not unconfigure the helper completely.
198 Please note that while this directive defines how Squid processes
199 authentication it does not automatically activate authentication.
200 To use authentication you must in addition make use of ACLs based
201 on login name in http_access (proxy_auth, proxy_auth_regex or
202 external with %LOGIN used in the format tag). The browser will be
203 challenged for authentication on the first such acl encountered
204 in http_access processing and will also be re-challenged for new
205 login credentials if the request is being denied by a proxy_auth
208 WARNING: authentication can't be used in a transparently intercepting
209 proxy as the client then thinks it is talking to an origin server and
210 not the proxy. This is a limitation of bending the TCP/IP protocol to
211 transparently intercepting port 80, not a limitation in Squid.
212 Ports flagged 'transparent', 'intercept', or 'tproxy' have
213 authentication disabled.
215 === Parameters for the basic scheme follow. ===
218 Specify the command for the external authenticator. Such a program
219 reads a line containing "username password" and replies "OK" or
220 "ERR" in an endless loop. "ERR" responses may optionally be followed
221 by a error description available as %m in the returned error page.
222 If you use an authenticator, make sure you have 1 acl of type
225 By default, the basic authentication scheme is not used unless a
226 program is specified.
228 If you want to use the traditional NCSA proxy authentication, set
229 this line to something like
231 auth_param basic program @DEFAULT_PREFIX@/libexec/ncsa_auth @DEFAULT_PREFIX@/etc/passwd
234 HTTP uses iso-latin-1 as characterset, while some authentication
235 backends such as LDAP expects UTF-8. If this is set to on Squid will
236 translate the HTTP iso-latin-1 charset to UTF-8 before sending the
237 username & password to the helper.
239 "children" numberofchildren [startup=N] [idle=N] [concurrency=N]
240 The maximum number of authenticator processes to spawn. If you start too few
241 Squid will have to wait for them to process a backlog of credential
242 verifications, slowing it down. When password verifications are
243 done via a (slow) network you are likely to need lots of
244 authenticator processes.
246 The startup= and idle= options permit some skew in the exact amount
247 run. A minimum of startup=N will begin during startup and reconfigure.
248 Squid will start more in groups of up to idle=N in an attempt to meet
249 traffic needs and to keep idle=N free above those traffic needs up to
252 The concurrency= option sets the number of concurrent requests the
253 helper can process. The default of 0 is used for helpers who only
254 supports one request at a time. Setting this to a number greater than
255 0 changes the protocol used to include a channel number first on the
256 request/response line, allowing multiple requests to be sent to the
257 same helper in parallell without wating for the response.
258 Must not be set unless it's known the helper supports this.
260 auth_param basic children 20 startup=0 idle=1
263 Specifies the realm name which is to be reported to the
264 client for the basic proxy authentication scheme (part of
265 the text the user will see when prompted their username and
266 password). There is no default.
267 auth_param basic realm Squid proxy-caching web server
269 "credentialsttl" timetolive
270 Specifies how long squid assumes an externally validated
271 username:password pair is valid for - in other words how
272 often the helper program is called for that user. Set this
273 low to force revalidation with short lived passwords. Note
274 setting this high does not impact your susceptibility
275 to replay attacks unless you are using an one-time password
276 system (such as SecureID). If you are using such a system,
277 you will be vulnerable to replay attacks unless you also
278 use the max_user_ip ACL in an http_access rule.
280 "casesensitive" on|off
281 Specifies if usernames are case sensitive. Most user databases are
282 case insensitive allowing the same username to be spelled using both
283 lower and upper case letters, but some are case sensitive. This
284 makes a big difference for user_max_ip ACL processing and similar.
285 auth_param basic casesensitive off
287 === Parameters for the digest scheme follow ===
290 Specify the command for the external authenticator. Such
291 a program reads a line containing "username":"realm" and
292 replies with the appropriate H(A1) value hex encoded or
293 ERR if the user (or his H(A1) hash) does not exists.
294 See rfc 2616 for the definition of H(A1).
295 "ERR" responses may optionally be followed by a error description
296 available as %m in the returned error page.
298 By default, the digest authentication scheme is not used unless a
299 program is specified.
301 If you want to use a digest authenticator, set this line to
304 auth_param digest program @DEFAULT_PREFIX@/bin/digest_pw_auth @DEFAULT_PREFIX@/etc/digpass
307 HTTP uses iso-latin-1 as characterset, while some authentication
308 backends such as LDAP expects UTF-8. If this is set to on Squid will
309 translate the HTTP iso-latin-1 charset to UTF-8 before sending the
310 username & password to the helper.
312 "children" numberofchildren [startup=N] [idle=N] [concurrency=N]
313 The maximum number of authenticator processes to spawn (default 5).
314 If you start too few Squid will have to wait for them to
315 process a backlog of H(A1) calculations, slowing it down.
316 When the H(A1) calculations are done via a (slow) network
317 you are likely to need lots of authenticator processes.
319 The startup= and idle= options permit some skew in the exact amount
320 run. A minimum of startup=N will begin during startup and reconfigure.
321 Squid will start more in groups of up to idle=N in an attempt to meet
322 traffic needs and to keep idle=N free above those traffic needs up to
325 The concurrency= option sets the number of concurrent requests the
326 helper can process. The default of 0 is used for helpers who only
327 supports one request at a time. Setting this to a number greater than
328 0 changes the protocol used to include a channel number first on the
329 request/response line, allowing multiple requests to be sent to the
330 same helper in parallell without wating for the response.
331 Must not be set unless it's known the helper supports this.
333 auth_param digest children 20 startup=0 idle=1
336 Specifies the realm name which is to be reported to the
337 client for the digest proxy authentication scheme (part of
338 the text the user will see when prompted their username and
339 password). There is no default.
340 auth_param digest realm Squid proxy-caching web server
342 "nonce_garbage_interval" timeinterval
343 Specifies the interval that nonces that have been issued
344 to client_agent's are checked for validity.
346 "nonce_max_duration" timeinterval
347 Specifies the maximum length of time a given nonce will be
350 "nonce_max_count" number
351 Specifies the maximum number of times a given nonce can be
354 "nonce_strictness" on|off
355 Determines if squid requires strict increment-by-1 behavior
356 for nonce counts, or just incrementing (off - for use when
357 useragents generate nonce counts that occasionally miss 1
358 (ie, 1,2,4,6)). Default off.
360 "check_nonce_count" on|off
361 This directive if set to off can disable the nonce count check
362 completely to work around buggy digest qop implementations in
363 certain mainstream browser versions. Default on to check the
364 nonce count to protect from authentication replay attacks.
366 "post_workaround" on|off
367 This is a workaround to certain buggy browsers who sends
368 an incorrect request digest in POST requests when reusing
369 the same nonce as acquired earlier on a GET request.
371 === NTLM scheme options follow ===
374 Specify the command for the external NTLM authenticator.
375 Such a program reads exchanged NTLMSSP packets with
376 the browser via Squid until authentication is completed.
377 If you use an NTLM authenticator, make sure you have 1 acl
378 of type proxy_auth. By default, the NTLM authenticator_program
381 auth_param ntlm program @DEFAULT_PREFIX@/bin/ntlm_auth
383 "children" numberofchildren [startup=N] [idle=N]
384 The maximum number of authenticator processes to spawn (default 5).
385 If you start too few Squid will have to wait for them to
386 process a backlog of credential verifications, slowing it
387 down. When credential verifications are done via a (slow)
388 network you are likely to need lots of authenticator
391 The startup= and idle= options permit some skew in the exact amount
392 run. A minimum of startup=N will begin during startup and reconfigure.
393 Squid will start more in groups of up to idle=N in an attempt to meet
394 traffic needs and to keep idle=N free above those traffic needs up to
397 auth_param ntlm children 20 startup=0 idle=1
400 If you experience problems with PUT/POST requests when using the
401 Negotiate authentication scheme then you can try setting this to
402 off. This will cause Squid to forcibly close the connection on
403 the initial requests where the browser asks which schemes are
404 supported by the proxy.
406 auth_param ntlm keep_alive on
408 === Options for configuring the NEGOTIATE auth-scheme follow ===
411 Specify the command for the external Negotiate authenticator.
412 This protocol is used in Microsoft Active-Directory enabled setups with
413 the Microsoft Internet Explorer or Mozilla Firefox browsers.
414 Its main purpose is to exchange credentials with the Squid proxy
415 using the Kerberos mechanisms.
416 If you use a Negotiate authenticator, make sure you have at least
417 one acl of type proxy_auth active. By default, the negotiate
418 authenticator_program is not used.
419 The only supported program for this role is the ntlm_auth
420 program distributed as part of Samba, version 4 or later.
422 auth_param negotiate program @DEFAULT_PREFIX@/bin/ntlm_auth --helper-protocol=gss-spnego
424 "children" numberofchildren [startup=N] [idle=N]
425 The maximum number of authenticator processes to spawn (default 5).
426 If you start too few Squid will have to wait for them to
427 process a backlog of credential verifications, slowing it
428 down. When crendential verifications are done via a (slow)
429 network you are likely to need lots of authenticator
432 The startup= and idle= options permit some skew in the exact amount
433 run. A minimum of startup=N will begin during startup and reconfigure.
434 Squid will start more in groups of up to idle=N in an attempt to meet
435 traffic needs and to keep idle=N free above those traffic needs up to
438 auth_param negotiate children 20 startup=0 idle=1
441 If you experience problems with PUT/POST requests when using the
442 Negotiate authentication scheme then you can try setting this to
443 off. This will cause Squid to forcibly close the connection on
444 the initial requests where the browser asks which schemes are
445 supported by the proxy.
447 auth_param negotiate keep_alive on
452 #Recommended minimum configuration per scheme:
453 #auth_param negotiate program <uncomment and complete this line to activate>
454 #auth_param negotiate children 20 startup=0 idle=1
455 #auth_param negotiate keep_alive on
457 #auth_param ntlm program <uncomment and complete this line to activate>
458 #auth_param ntlm children 20 startup=0 idle=1
459 #auth_param ntlm keep_alive on
461 #auth_param digest program <uncomment and complete this line>
462 #auth_param digest children 20 startup=0 idle=1
463 #auth_param digest realm Squid proxy-caching web server
464 #auth_param digest nonce_garbage_interval 5 minutes
465 #auth_param digest nonce_max_duration 30 minutes
466 #auth_param digest nonce_max_count 50
468 #auth_param basic program <uncomment and complete this line>
469 #auth_param basic children 5 startup=5 idle=1
470 #auth_param basic realm Squid proxy-caching web server
471 #auth_param basic credentialsttl 2 hours
474 NAME: authenticate_cache_garbage_interval
477 LOC: Config.authenticateGCInterval
479 The time period between garbage collection across the username cache.
480 This is a tradeoff between memory utilization (long intervals - say
481 2 days) and CPU (short intervals - say 1 minute). Only change if you
485 NAME: authenticate_ttl
488 LOC: Config.authenticateTTL
490 The time a user & their credentials stay in the logged in
491 user cache since their last request. When the garbage
492 interval passes, all user credentials that have passed their
493 TTL are removed from memory.
496 NAME: authenticate_ip_ttl
498 LOC: Config.authenticateIpTTL
501 If you use proxy authentication and the 'max_user_ip' ACL,
502 this directive controls how long Squid remembers the IP
503 addresses associated with each user. Use a small value
504 (e.g., 60 seconds) if your users might change addresses
505 quickly, as is the case with dialups. You might be safe
506 using a larger value (e.g., 2 hours) in a corporate LAN
507 environment with relatively static address assignments.
512 -----------------------------------------------------------------------------
515 NAME: external_acl_type
516 TYPE: externalAclHelper
517 LOC: Config.externalAclHelperList
520 This option defines external acl classes using a helper program
521 to look up the status
523 external_acl_type name [options] FORMAT.. /path/to/helper [helper arguments..]
527 ttl=n TTL in seconds for cached results (defaults to 3600
530 TTL for cached negative lookups (default same
533 Maximum number of acl helper processes spawned to service
534 external acl lookups of this type. (default 20)
536 Minimum number of acl helper processes to spawn during
537 startup and reconfigure to service external acl lookups
538 of this type. (default 0)
540 Number of acl helper processes to keep ahead of traffic
541 loads. Squid will spawn this many at once whenever load
542 rises above the capabilities of existing processes.
543 Up to the value of children-max. (default 1)
544 concurrency=n concurrency level per process. Only used with helpers
545 capable of processing more than one query at a time.
546 cache=n limit the result cache size, default is unbounded.
547 grace=n Percentage remaining of TTL where a refresh of a
548 cached entry should be initiated without needing to
549 wait for a new reply. (default is for no grace period)
550 protocol=2.5 Compatibility mode for Squid-2.5 external acl helpers
551 ipv4 / ipv6 IP-mode used to communicate to this helper.
552 For compatability with older configurations and helpers
553 the default is currently 'ipv4'.
555 FORMAT specifications
557 %LOGIN Authenticated user login name
558 %EXT_USER Username from external acl
559 %IDENT Ident user name
561 %SRCPORT Client source port
564 %PROTO Requested protocol
566 %PATH Requested URL path
567 %METHOD Request method
568 %MYADDR Squid interface address
569 %MYPORT Squid http_port number
570 %PATH Requested URL-path (including query-string if any)
571 %USER_CERT SSL User certificate in PEM format
572 %USER_CERTCHAIN SSL User certificate chain in PEM format
573 %USER_CERT_xx SSL User certificate subject attribute xx
574 %USER_CA_xx SSL User certificate issuer attribute xx
576 %>{Header} HTTP request header "Header"
578 HTTP request header "Hdr" list member "member"
580 HTTP request header list member using ; as
581 list separator. ; can be any non-alphanumeric
584 %<{Header} HTTP reply header "Header"
586 HTTP reply header "Hdr" list member "member"
588 HTTP reply header list member using ; as
589 list separator. ; can be any non-alphanumeric
592 In addition to the above, any string specified in the referencing
593 acl will also be included in the helper request line, after the
594 specified formats (see the "acl external" directive)
596 The helper receives lines per the above format specification,
597 and returns lines starting with OK or ERR indicating the validity
598 of the request and optionally followed by additional keywords with
601 General result syntax:
603 OK/ERR keyword=value ...
607 user= The users name (login)
608 password= The users password (for login= cache_peer option)
609 message= Message describing the reason. Available as %o
611 tag= Apply a tag to a request (for both ERR and OK results)
612 Only sets a tag, does not alter existing tags.
613 log= String to be logged in access.log. Available as
614 %ea in logformat specifications
616 If protocol=3.0 (the default) then URL escaping is used to protect
617 each value in both requests and responses.
619 If using protocol=2.5 then all values need to be enclosed in quotes
620 if they may contain whitespace, or the whitespace escaped using \.
621 And quotes or \ characters within the keyword value must be \ escaped.
623 When using the concurrency= option the protocol is changed by
624 introducing a query channel tag infront of the request/response.
625 The query channel tag is a number between 0 and concurrency-1.
633 Defining an Access List
635 Every access list definition must begin with an aclname and acltype,
636 followed by either type-specific arguments or a quoted filename that
639 acl aclname acltype argument ...
640 acl aclname acltype "file" ...
642 When using "file", the file should contain one item per line.
644 By default, regular expressions are CASE-SENSITIVE. To make
645 them case-insensitive, use the -i option.
647 Some acl types require suspending the current request in order
648 to access some external data source.
649 Those which do are marked with the tag [slow], those which
650 don't are marked as [fast].
651 See http://wiki.squid-cache.org/SquidFaq/SquidAcl
652 for further information
654 ***** ACL TYPES AVAILABLE *****
656 acl aclname src ip-address/netmask ... # clients IP address [fast]
657 acl aclname src addr1-addr2/netmask ... # range of addresses [fast]
658 acl aclname dst ip-address/netmask ... # URL host's IP address [slow]
659 acl aclname myip ip-address/netmask ... # local socket IP address [fast]
661 acl aclname arp mac-address ... (xx:xx:xx:xx:xx:xx notation)
662 # The arp ACL requires the special configure option --enable-arp-acl.
663 # Furthermore, the ARP ACL code is not portable to all operating systems.
664 # It works on Linux, Solaris, Windows, FreeBSD, and some
665 # other *BSD variants.
668 # NOTE: Squid can only determine the MAC address for clients that are on
669 # the same subnet. If the client is on a different subnet,
670 # then Squid cannot find out its MAC address.
672 acl aclname srcdomain .foo.com ...
673 # reverse lookup, from client IP [slow]
674 acl aclname dstdomain .foo.com ...
675 # Destination server from URL [fast]
676 acl aclname srcdom_regex [-i] \.foo\.com ...
677 # regex matching client name [slow]
678 acl aclname dstdom_regex [-i] \.foo\.com ...
679 # regex matching server [fast]
681 # For dstdomain and dstdom_regex a reverse lookup is tried if a IP
682 # based URL is used and no match is found. The name "none" is used
683 # if the reverse lookup fails.
685 acl aclname src_as number ...
686 acl aclname dst_as number ...
688 # Except for access control, AS numbers can be used for
689 # routing of requests to specific caches. Here's an
690 # example for routing all requests for AS#1241 and only
691 # those to mycache.mydomain.net:
692 # acl asexample dst_as 1241
693 # cache_peer_access mycache.mydomain.net allow asexample
694 # cache_peer_access mycache_mydomain.net deny all
696 acl aclname peername myPeer ...
698 # match against a named cache_peer entry
699 # set unique name= on cache_peer lines for reliable use.
701 acl aclname time [day-abbrevs] [h1:m1-h2:m2]
711 # h1:m1 must be less than h2:m2
713 acl aclname url_regex [-i] ^http:// ...
714 # regex matching on whole URL [fast]
715 acl aclname urlpath_regex [-i] \.gif$ ...
716 # regex matching on URL path [fast]
718 acl aclname port 80 70 21 0-1024... # destination TCP port [fast]
720 acl aclname myport 3128 ... # local socket TCP port [fast]
721 acl aclname myportname 3128 ... # http(s)_port name [fast]
723 acl aclname proto HTTP FTP ... # request protocol [fast]
725 acl aclname method GET POST ... # HTTP request method [fast]
727 acl aclname http_status 200 301 500- 400-403 ...
728 # status code in reply [fast]
730 acl aclname browser [-i] regexp ...
731 # pattern match on User-Agent header (see also req_header below) [fast]
733 acl aclname referer_regex [-i] regexp ...
734 # pattern match on Referer header [fast]
735 # Referer is highly unreliable, so use with care
737 acl aclname ident username ...
738 acl aclname ident_regex [-i] pattern ...
739 # string match on ident output [slow]
740 # use REQUIRED to accept any non-null ident.
742 acl aclname proxy_auth [-i] username ...
743 acl aclname proxy_auth_regex [-i] pattern ...
744 # perform http authentication challenge to the client and match against
745 # supplied credentials [slow]
747 # takes a list of allowed usernames.
748 # use REQUIRED to accept any valid username.
750 # Will use proxy authentication in forward-proxy scenarios, and plain
751 # http authenticaiton in reverse-proxy scenarios
753 # NOTE: when a Proxy-Authentication header is sent but it is not
754 # needed during ACL checking the username is NOT logged
757 # NOTE: proxy_auth requires a EXTERNAL authentication program
758 # to check username/password combinations (see
759 # auth_param directive).
761 # NOTE: proxy_auth can't be used in a transparent/intercepting proxy
762 # as the browser needs to be configured for using a proxy in order
763 # to respond to proxy authentication.
765 acl aclname snmp_community string ...
766 # A community string to limit access to your SNMP Agent [fast]
769 # acl snmppublic snmp_community public
771 acl aclname maxconn number
772 # This will be matched when the client's IP address has
773 # more than <number> HTTP connections established. [fast]
775 acl aclname max_user_ip [-s] number
776 # This will be matched when the user attempts to log in from more
777 # than <number> different ip addresses. The authenticate_ip_ttl
778 # parameter controls the timeout on the ip entries. [fast]
779 # If -s is specified the limit is strict, denying browsing
780 # from any further IP addresses until the ttl has expired. Without
781 # -s Squid will just annoy the user by "randomly" denying requests.
782 # (the counter is reset each time the limit is reached and a
784 # NOTE: in acceleration mode or where there is mesh of child proxies,
785 # clients may appear to come from multiple addresses if they are
786 # going through proxy farms, so a limit of 1 may cause user problems.
788 acl aclname random probability
789 # Pseudo-randomly match requests. Based on the probability given.
790 # Probability may be written as a decimal (0.333), fraction (1/3)
791 # or ratio of matches:non-matches (3:5).
793 acl aclname req_mime_type [-i] mime-type ...
794 # regex match against the mime type of the request generated
795 # by the client. Can be used to detect file upload or some
796 # types HTTP tunneling requests [fast]
797 # NOTE: This does NOT match the reply. You cannot use this
798 # to match the returned file type.
800 acl aclname req_header header-name [-i] any\.regex\.here
801 # regex match against any of the known request headers. May be
802 # thought of as a superset of "browser", "referer" and "mime-type"
805 acl aclname rep_mime_type [-i] mime-type ...
806 # regex match against the mime type of the reply received by
807 # squid. Can be used to detect file download or some
808 # types HTTP tunneling requests. [fast]
809 # NOTE: This has no effect in http_access rules. It only has
810 # effect in rules that affect the reply data stream such as
813 acl aclname rep_header header-name [-i] any\.regex\.here
814 # regex match against any of the known reply headers. May be
815 # thought of as a superset of "browser", "referer" and "mime-type"
818 acl aclname external class_name [arguments...]
819 # external ACL lookup via a helper class defined by the
820 # external_acl_type directive [slow]
822 acl aclname user_cert attribute values...
823 # match against attributes in a user SSL certificate
824 # attribute is one of DN/C/O/CN/L/ST [fast]
826 acl aclname ca_cert attribute values...
827 # match against attributes a users issuing CA SSL certificate
828 # attribute is one of DN/C/O/CN/L/ST [fast]
830 acl aclname ext_user username ...
831 acl aclname ext_user_regex [-i] pattern ...
832 # string match on username returned by external acl helper [slow]
833 # use REQUIRED to accept any non-null user name.
835 acl aclname tag tagvalue ...
836 # string match on tag returned by external acl helper [slow]
838 acl aclname hier_code codename ...
839 # string match against squid hierarchy code(s); [fast]
840 # e.g., DIRECT, PARENT_HIT, NONE, etc.
842 # NOTE: This has no effect in http_access rules. It only has
843 # effect in rules that affect the reply data stream such as
847 acl macaddress arp 09:00:2b:23:45:67
848 acl myexample dst_as 1241
849 acl password proxy_auth REQUIRED
850 acl fileupload req_mime_type -i ^multipart/form-data$
851 acl javascript rep_mime_type -i ^application/x-javascript$
855 # Recommended minimum configuration:
857 acl manager proto cache_object
858 acl localhost src 127.0.0.1/32 ::1
859 acl to_localhost dst 127.0.0.0/8 0.0.0.0/32 ::1
861 # Example rule allowing access from your local networks.
862 # Adapt to list your (internal) IP networks from where browsing
864 acl localnet src 10.0.0.0/8 # RFC1918 possible internal network
865 acl localnet src 172.16.0.0/12 # RFC1918 possible internal network
866 acl localnet src 192.168.0.0/16 # RFC1918 possible internal network
867 acl localnet src fc00::/7 # RFC 4193 local private network range
868 acl localnet src fe80::/10 # RFC 4291 link-local (directly plugged) machines
870 acl SSL_ports port 443
871 acl Safe_ports port 80 # http
872 acl Safe_ports port 21 # ftp
873 acl Safe_ports port 443 # https
874 acl Safe_ports port 70 # gopher
875 acl Safe_ports port 210 # wais
876 acl Safe_ports port 1025-65535 # unregistered ports
877 acl Safe_ports port 280 # http-mgmt
878 acl Safe_ports port 488 # gss-http
879 acl Safe_ports port 591 # filemaker
880 acl Safe_ports port 777 # multiling http
881 acl CONNECT method CONNECT
885 NAME: follow_x_forwarded_for
887 IFDEF: FOLLOW_X_FORWARDED_FOR
888 LOC: Config.accessList.followXFF
889 DEFAULT_IF_NONE: deny all
891 Allowing or Denying the X-Forwarded-For header to be followed to
892 find the original source of a request.
894 Requests may pass through a chain of several other proxies
895 before reaching us. The X-Forwarded-For header will contain a
896 comma-separated list of the IP addresses in the chain, with the
897 rightmost address being the most recent.
899 If a request reaches us from a source that is allowed by this
900 configuration item, then we consult the X-Forwarded-For header
901 to see where that host received the request from. If the
902 X-Forwarded-For header contains multiple addresses, we continue
903 backtracking until we reach an address for which we are not allowed
904 to follow the X-Forwarded-For header, or until we reach the first
905 address in the list. For the purpose of ACL used in the
906 follow_x_forwarded_for directive the src ACL type always matches
907 the address we are testing and srcdomain matches its rDNS.
909 The end result of this process is an IP address that we will
910 refer to as the indirect client address. This address may
911 be treated as the client address for access control, ICAP, delay
912 pools and logging, depending on the acl_uses_indirect_client,
913 icap_uses_indirect_client, delay_pool_uses_indirect_client,
914 log_uses_indirect_client and tproxy_uses_indirect_client options.
916 This clause only supports fast acl types.
917 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
919 SECURITY CONSIDERATIONS:
921 Any host for which we follow the X-Forwarded-For header
922 can place incorrect information in the header, and Squid
923 will use the incorrect information as if it were the
924 source address of the request. This may enable remote
925 hosts to bypass any access control restrictions that are
926 based on the client's source addresses.
930 acl localhost src 127.0.0.1
931 acl my_other_proxy srcdomain .proxy.example.com
932 follow_x_forwarded_for allow localhost
933 follow_x_forwarded_for allow my_other_proxy
936 NAME: acl_uses_indirect_client
939 IFDEF: FOLLOW_X_FORWARDED_FOR
941 LOC: Config.onoff.acl_uses_indirect_client
943 Controls whether the indirect client address
944 (see follow_x_forwarded_for) is used instead of the
945 direct client address in acl matching.
948 NAME: delay_pool_uses_indirect_client
951 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_DELAY_POOLS
953 LOC: Config.onoff.delay_pool_uses_indirect_client
955 Controls whether the indirect client address
956 (see follow_x_forwarded_for) is used instead of the
957 direct client address in delay pools.
960 NAME: log_uses_indirect_client
963 IFDEF: FOLLOW_X_FORWARDED_FOR
965 LOC: Config.onoff.log_uses_indirect_client
967 Controls whether the indirect client address
968 (see follow_x_forwarded_for) is used instead of the
969 direct client address in the access log.
972 NAME: tproxy_uses_indirect_client
975 IFDEF: FOLLOW_X_FORWARDED_FOR&&LINUX_NETFILTER
977 LOC: Config.onoff.tproxy_uses_indirect_client
979 Controls whether the indirect client address
980 (see follow_x_forwarded_for) is used instead of the
981 direct client address when spoofing the outgoing client.
983 This has no effect on requests arriving in non-tproxy
986 SECURITY WARNING: Usage of this option is dangerous
987 and should not be used trivially. Correct configuration
988 of folow_x_forewarded_for with a limited set of trusted
989 sources is required to prevent abuse of your proxy.
994 LOC: Config.accessList.http
995 DEFAULT_IF_NONE: deny all
997 Allowing or Denying access based on defined access lists
999 Access to the HTTP port:
1000 http_access allow|deny [!]aclname ...
1002 NOTE on default values:
1004 If there are no "access" lines present, the default is to deny
1007 If none of the "access" lines cause a match, the default is the
1008 opposite of the last line in the list. If the last line was
1009 deny, the default is allow. Conversely, if the last line
1010 is allow, the default will be deny. For these reasons, it is a
1011 good idea to have an "deny all" entry at the end of your access
1012 lists to avoid potential confusion.
1014 This clause supports both fast and slow acl types.
1015 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1020 # Recommended minimum Access Permission configuration:
1022 # Only allow cachemgr access from localhost
1023 http_access allow manager localhost
1024 http_access deny manager
1026 # Deny requests to certain unsafe ports
1027 http_access deny !Safe_ports
1029 # Deny CONNECT to other than secure SSL ports
1030 http_access deny CONNECT !SSL_ports
1032 # We strongly recommend the following be uncommented to protect innocent
1033 # web applications running on the proxy server who think the only
1034 # one who can access services on "localhost" is a local user
1035 #http_access deny to_localhost
1038 # INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS
1041 # Example rule allowing access from your local networks.
1042 # Adapt localnet in the ACL section to list your (internal) IP networks
1043 # from where browsing should be allowed
1044 http_access allow localnet
1045 http_access allow localhost
1047 # And finally deny all other access to this proxy
1048 http_access deny all
1052 NAME: adapted_http_access http_access2
1054 LOC: Config.accessList.adapted_http
1057 Allowing or Denying access based on defined access lists
1059 Essentially identical to http_access, but runs after redirectors
1060 and ICAP/eCAP adaptation. Allowing access control based on their
1063 If not set then only http_access is used.
1066 NAME: http_reply_access
1068 LOC: Config.accessList.reply
1071 Allow replies to client requests. This is complementary to http_access.
1073 http_reply_access allow|deny [!] aclname ...
1075 NOTE: if there are no access lines present, the default is to allow
1078 If none of the access lines cause a match the opposite of the
1079 last line will apply. Thus it is good practice to end the rules
1080 with an "allow all" or "deny all" entry.
1082 This clause supports both fast and slow acl types.
1083 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1088 LOC: Config.accessList.icp
1089 DEFAULT_IF_NONE: deny all
1091 Allowing or Denying access to the ICP port based on defined
1094 icp_access allow|deny [!]aclname ...
1096 See http_access for details
1098 This clause only supports fast acl types.
1099 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1101 # Allow ICP queries from local networks only
1102 #icp_access allow localnet
1103 #icp_access deny all
1109 LOC: Config.accessList.htcp
1110 DEFAULT_IF_NONE: deny all
1112 Allowing or Denying access to the HTCP port based on defined
1115 htcp_access allow|deny [!]aclname ...
1117 See http_access for details
1119 NOTE: The default if no htcp_access lines are present is to
1120 deny all traffic. This default may cause problems with peers
1121 using the htcp option.
1123 This clause only supports fast acl types.
1124 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1126 # Allow HTCP queries from local networks only
1127 #htcp_access allow localnet
1128 #htcp_access deny all
1131 NAME: htcp_clr_access
1134 LOC: Config.accessList.htcp_clr
1135 DEFAULT_IF_NONE: deny all
1137 Allowing or Denying access to purge content using HTCP based
1138 on defined access lists
1140 htcp_clr_access allow|deny [!]aclname ...
1142 See http_access for details
1144 This clause only supports fast acl types.
1145 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1147 # Allow HTCP CLR requests from trusted peers
1148 acl htcp_clr_peer src 172.16.1.2
1149 htcp_clr_access allow htcp_clr_peer
1154 LOC: Config.accessList.miss
1157 Use to force your neighbors to use you as a sibling instead of
1158 a parent. For example:
1160 acl localclients src 172.16.0.0/16
1161 miss_access allow localclients
1162 miss_access deny !localclients
1164 This means only your local clients are allowed to fetch
1165 MISSES and all other clients can only fetch HITS.
1167 By default, allow all clients who passed the http_access rules
1168 to fetch MISSES from us.
1170 This clause only supports fast acl types.
1171 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1174 NAME: ident_lookup_access
1177 DEFAULT_IF_NONE: deny all
1178 LOC: Ident::TheConfig.identLookup
1180 A list of ACL elements which, if matched, cause an ident
1181 (RFC 931) lookup to be performed for this request. For
1182 example, you might choose to always perform ident lookups
1183 for your main multi-user Unix boxes, but not for your Macs
1184 and PCs. By default, ident lookups are not performed for
1187 To enable ident lookups for specific client addresses, you
1188 can follow this example:
1190 acl ident_aware_hosts src 198.168.1.0/24
1191 ident_lookup_access allow ident_aware_hosts
1192 ident_lookup_access deny all
1194 Only src type ACL checks are fully supported. A srcdomain
1195 ACL might work at times, but it will not always provide
1198 This clause only supports fast acl types.
1199 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1202 NAME: reply_body_max_size
1203 COMMENT: size [acl acl...]
1206 LOC: Config.ReplyBodySize
1208 This option specifies the maximum size of a reply body. It can be
1209 used to prevent users from downloading very large files, such as
1210 MP3's and movies. When the reply headers are received, the
1211 reply_body_max_size lines are processed, and the first line where
1212 all (if any) listed ACLs are true is used as the maximum body size
1215 This size is checked twice. First when we get the reply headers,
1216 we check the content-length value. If the content length value exists
1217 and is larger than the allowed size, the request is denied and the
1218 user receives an error message that says "the request or reply
1219 is too large." If there is no content-length, and the reply
1220 size exceeds this limit, the client's connection is just closed
1221 and they will receive a partial reply.
1223 WARNING: downstream caches probably can not detect a partial reply
1224 if there is no content-length header, so they will cache
1225 partial responses and give them out as hits. You should NOT
1226 use this option if you have downstream caches.
1228 WARNING: A maximum size smaller than the size of squid's error messages
1229 will cause an infinite loop and crash squid. Ensure that the smallest
1230 non-zero value you use is greater that the maximum header size plus
1231 the size of your largest error page.
1233 If you set this parameter none (the default), there will be
1236 Configuration Format is:
1237 reply_body_max_size SIZE UNITS [acl ...]
1239 reply_body_max_size 10 MB
1245 -----------------------------------------------------------------------------
1248 NAME: http_port ascii_port
1249 TYPE: http_port_list
1251 LOC: Config.Sockaddr.http
1253 Usage: port [mode] [options]
1254 hostname:port [mode] [options]
1255 1.2.3.4:port [mode] [options]
1257 The socket addresses where Squid will listen for HTTP client
1258 requests. You may specify multiple socket addresses.
1259 There are three forms: port alone, hostname with port, and
1260 IP address with port. If you specify a hostname or IP
1261 address, Squid binds the socket to that specific
1262 address. Most likely, you do not need to bind to a specific
1263 address, so you can use the port number alone.
1265 If you are running Squid in accelerator mode, you
1266 probably want to listen on port 80 also, or instead.
1268 The -a command line option may be used to specify additional
1269 port(s) where Squid listens for proxy request. Such ports will
1270 be plain proxy ports with no options.
1272 You may specify multiple socket addresses on multiple lines.
1276 intercept Support for IP-Layer interception of
1277 outgoing requests without browser settings.
1278 NP: disables authentication and IPv6 on the port.
1280 tproxy Support Linux TPROXY for spoofing outgoing
1281 connections using the client IP address.
1282 NP: disables authentication and maybe IPv6 on the port.
1284 accel Accelerator mode. Also needs at least one of
1285 vhost / vport / defaultsite.
1287 ssl-bump Intercept each CONNECT request matching ssl_bump ACL,
1288 establish secure connection with the client and with
1289 the server, decrypt HTTP messages as they pass through
1290 Squid, and treat them as unencrypted HTTP messages,
1291 becoming the man-in-the-middle.
1293 The ssl_bump option is required to fully enable
1294 the SslBump feature.
1296 Omitting the mode flag causes default forward proxy mode to be used.
1299 Accelerator Mode Options:
1301 allow-direct Allow direct forwarding in accelerator mode. Normally
1302 accelerated requests are denied direct forwarding as if
1303 never_direct was used.
1305 defaultsite=domainname
1306 What to use for the Host: header if it is not present
1307 in a request. Determines what site (not origin server)
1308 accelerators should consider the default.
1311 vhost Using the Host header for virtual domain support.
1312 Also uses the port as specified in Host: header.
1314 vport IP based virtual host support. Using the http_port number
1315 in passed on Host: headers.
1317 vport=NN Uses the specified port number rather than the
1320 protocol= Protocol to reconstruct accelerated requests with.
1321 Defaults to http://.
1323 ignore-cc Ignore request Cache-Control headers.
1325 Warning: This option violates HTTP specifications if
1326 used in non-accelerator setups.
1329 SSL Bump Mode Options:
1331 cert= Path to SSL certificate (PEM format).
1333 key= Path to SSL private key file (PEM format)
1334 if not specified, the certificate file is
1335 assumed to be a combined certificate and
1338 version= The version of SSL/TLS supported
1339 1 automatic (default)
1344 cipher= Colon separated list of supported ciphers.
1346 options= Various SSL engine options. The most important
1348 NO_SSLv2 Disallow the use of SSLv2
1349 NO_SSLv3 Disallow the use of SSLv3
1350 NO_TLSv1 Disallow the use of TLSv1
1351 SINGLE_DH_USE Always create a new key when using
1352 temporary/ephemeral DH key exchanges
1353 See src/ssl_support.c or OpenSSL SSL_CTX_set_options
1354 documentation for a complete list of options.
1356 clientca= File containing the list of CAs to use when
1357 requesting a client certificate.
1359 cafile= File containing additional CA certificates to
1360 use when verifying client certificates. If unset
1361 clientca will be used.
1363 capath= Directory containing additional CA certificates
1364 and CRL lists to use when verifying client certificates.
1366 crlfile= File of additional CRL lists to use when verifying
1367 the client certificate, in addition to CRLs stored in
1368 the capath. Implies VERIFY_CRL flag below.
1370 dhparams= File containing DH parameters for temporary/ephemeral
1373 sslflags= Various flags modifying the use of SSL:
1375 Don't request client certificates
1376 immediately, but wait until acl processing
1377 requires a certificate (not yet implemented).
1379 Don't use the default CA lists built in
1382 Don't allow for session reuse. Each connection
1383 will result in a new SSL session.
1385 Verify CRL lists when accepting client
1388 Verify CRL lists for all certificates in the
1389 client certificate chain.
1391 sslcontext= SSL session ID context identifier.
1393 generate-host-certificates[=<on|off>]
1394 Dynamically create SSL server certificates for the
1395 destination hosts of bumped CONNECT requests.When
1396 enabled, the cert and key options are used to sign
1397 generated certificates. Otherwise generated
1398 certificate will be selfsigned.
1399 If there is CA certificate life time of generated
1400 certificate equals lifetime of CA certificate. If
1401 generated certificate is selfsigned lifetime is three
1403 This option is enabled by default when SslBump is used.
1404 See the sslBump option above for more information.
1406 dynamic_cert_mem_cache_size=SIZE
1407 Approximate total RAM size spent on cached generated
1408 certificates. If set to zero, caching is disabled. The
1409 default value is 4MB. An average XXX-bit certificate
1410 consumes about XXX bytes of RAM.
1414 connection-auth[=on|off]
1415 use connection-auth=off to tell Squid to prevent
1416 forwarding Microsoft connection oriented authentication
1417 (NTLM, Negotiate and Kerberos)
1419 disable-pmtu-discovery=
1420 Control Path-MTU discovery usage:
1421 off lets OS decide on what to do (default).
1422 transparent disable PMTU discovery when transparent
1424 always disable always PMTU discovery.
1426 In many setups of transparently intercepting proxies
1427 Path-MTU discovery can not work on traffic towards the
1428 clients. This is the case when the intercepting device
1429 does not fully track connections and fails to forward
1430 ICMP must fragment messages to the cache server. If you
1431 have such setup and experience that certain clients
1432 sporadically hang or never complete requests set
1433 disable-pmtu-discovery option to 'transparent'.
1435 name= Specifies a internal name for the port. Defaults to
1436 the port specification (port or addr:port)
1438 tcpkeepalive[=idle,interval,timeout]
1439 Enable TCP keepalive probes of idle connections.
1440 In seconds; idle is the initial time before TCP starts
1441 probing the connection, interval how often to probe, and
1442 timeout the time before giving up.
1444 If you run Squid on a dual-homed machine with an internal
1445 and an external interface we recommend you to specify the
1446 internal address:port in http_port. This way Squid will only be
1447 visible on the internal address.
1451 # Squid normally listens to port 3128
1452 http_port @DEFAULT_HTTP_PORT@
1458 TYPE: https_port_list
1460 LOC: Config.Sockaddr.https
1462 Usage: [ip:]port cert=certificate.pem [key=key.pem] [options...]
1464 The socket address where Squid will listen for HTTPS client
1467 This is really only useful for situations where you are running
1468 squid in accelerator mode and you want to do the SSL work at the
1471 You may specify multiple socket addresses on multiple lines,
1472 each with their own SSL certificate and/or options.
1476 accel Accelerator mode. Also needs at least one of
1477 defaultsite or vhost.
1479 defaultsite= The name of the https site presented on
1480 this port. Implies accel.
1482 vhost Accelerator mode using Host header for virtual
1483 domain support. Requires a wildcard certificate
1484 or other certificate valid for more than one domain.
1487 protocol= Protocol to reconstruct accelerated requests with.
1490 cert= Path to SSL certificate (PEM format).
1492 key= Path to SSL private key file (PEM format)
1493 if not specified, the certificate file is
1494 assumed to be a combined certificate and
1497 version= The version of SSL/TLS supported
1498 1 automatic (default)
1503 cipher= Colon separated list of supported ciphers.
1505 options= Various SSL engine options. The most important
1507 NO_SSLv2 Disallow the use of SSLv2
1508 NO_SSLv3 Disallow the use of SSLv3
1509 NO_TLSv1 Disallow the use of TLSv1
1510 SINGLE_DH_USE Always create a new key when using
1511 temporary/ephemeral DH key exchanges
1512 See src/ssl_support.c or OpenSSL SSL_CTX_set_options
1513 documentation for a complete list of options.
1515 clientca= File containing the list of CAs to use when
1516 requesting a client certificate.
1518 cafile= File containing additional CA certificates to
1519 use when verifying client certificates. If unset
1520 clientca will be used.
1522 capath= Directory containing additional CA certificates
1523 and CRL lists to use when verifying client certificates.
1525 crlfile= File of additional CRL lists to use when verifying
1526 the client certificate, in addition to CRLs stored in
1527 the capath. Implies VERIFY_CRL flag below.
1529 dhparams= File containing DH parameters for temporary/ephemeral
1532 sslflags= Various flags modifying the use of SSL:
1534 Don't request client certificates
1535 immediately, but wait until acl processing
1536 requires a certificate (not yet implemented).
1538 Don't use the default CA lists built in
1541 Don't allow for session reuse. Each connection
1542 will result in a new SSL session.
1544 Verify CRL lists when accepting client
1547 Verify CRL lists for all certificates in the
1548 client certificate chain.
1550 sslcontext= SSL session ID context identifier.
1552 vport Accelerator with IP based virtual host support.
1554 vport=NN As above, but uses specified port number rather
1555 than the https_port number. Implies accel.
1557 name= Specifies a internal name for the port. Defaults to
1558 the port specification (port or addr:port)
1562 NAME: tcp_outgoing_tos tcp_outgoing_ds tcp_outgoing_dscp
1565 LOC: Ip::Qos::TheConfig.tosToServer
1567 Allows you to select a TOS/Diffserv value for packets outgoing
1568 on the server side, based on an ACL.
1570 tcp_outgoing_tos ds-field [!]aclname ...
1572 Example where normal_service_net uses the TOS value 0x00
1573 and good_service_net uses 0x20
1575 acl normal_service_net src 10.0.0.0/24
1576 acl good_service_net src 10.0.1.0/24
1577 tcp_outgoing_tos 0x00 normal_service_net
1578 tcp_outgoing_tos 0x20 good_service_net
1580 TOS/DSCP values really only have local significance - so you should
1581 know what you're specifying. For more information, see RFC2474,
1582 RFC2475, and RFC3260.
1584 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
1585 "default" to use whatever default your host has. Note that in
1586 practice often only multiples of 4 is usable as the two rightmost bits
1587 have been redefined for use by ECN (RFC 3168 section 23.1).
1589 Processing proceeds in the order specified, and stops at first fully
1593 NAME: clientside_tos
1596 LOC: Ip::Qos::TheConfig.tosToClient
1598 Allows you to select a TOS/Diffserv value for packets being transmitted
1599 on the client-side, based on an ACL.
1601 clientside_tos ds-field [!]aclname ...
1603 Example where normal_service_net uses the TOS value 0x00
1604 and good_service_net uses 0x20
1606 acl normal_service_net src 10.0.0.0/24
1607 acl good_service_net src 10.0.1.0/24
1608 clientside_tos 0x00 normal_service_net
1609 clientside_tos 0x20 good_service_net
1611 Note: This feature is incompatible with qos_flows. Any TOS values set here
1612 will be overwritten by TOS values in qos_flows.
1615 NAME: tcp_outgoing_mark
1619 LOC: Ip::Qos::TheConfig.nfmarkToServer
1621 Allows you to apply a Netfilter mark value to outgoing packets
1622 on the server side, based on an ACL.
1624 tcp_outgoing_mark mark-value [!]aclname ...
1626 Example where normal_service_net uses the mark value 0x00
1627 and good_service_net uses 0x20
1629 acl normal_service_net src 10.0.0.0/24
1630 acl good_service_net src 10.0.1.0/24
1631 tcp_outgoing_mark 0x00 normal_service_net
1632 tcp_outgoing_mark 0x20 good_service_net
1635 NAME: clientside_mark
1639 LOC: Ip::Qos::TheConfig.nfmarkToClient
1641 Allows you to apply a Netfilter mark value to packets being transmitted
1642 on the client-side, based on an ACL.
1644 clientside_mark mark-value [!]aclname ...
1646 Example where normal_service_net uses the mark value 0x00
1647 and good_service_net uses 0x20
1649 acl normal_service_net src 10.0.0.0/24
1650 acl good_service_net src 10.0.1.0/24
1651 clientside_mark 0x00 normal_service_net
1652 clientside_mark 0x20 good_service_net
1654 Note: This feature is incompatible with qos_flows. Any mark values set here
1655 will be overwritten by mark values in qos_flows.
1662 LOC: Ip::Qos::TheConfig
1664 Allows you to select a TOS/DSCP value to mark outgoing
1665 connections with, based on where the reply was sourced. For
1666 platforms using netfilter, allows you to set a netfilter mark
1667 value instead of, or in addition to, a TOS value.
1669 TOS values really only have local significance - so you should
1670 know what you're specifying. For more information, see RFC2474,
1671 RFC2475, and RFC3260.
1673 The TOS/DSCP byte must be exactly that - a octet value 0 - 255. Note that
1674 in practice often only multiples of 4 is usable as the two rightmost bits
1675 have been redefined for use by ECN (RFC 3168 section 23.1).
1677 Mark values can be any unsigned 32-bit integer value.
1679 This setting is configured by setting the following values:
1681 tos|mark Whether to set TOS or netfilter mark values
1683 local-hit=0xFF Value to mark local cache hits.
1685 sibling-hit=0xFF Value to mark hits from sibling peers.
1687 parent-hit=0xFF Value to mark hits from parent peers.
1689 miss=0xFF Value to mark cache misses. Takes precedence
1690 over the preserve-miss feature (see below).
1692 The TOS variant of the following features are only possible on Linux
1693 and require your kernel to be patched with the TOS preserving ZPH
1694 patch, available from http://zph.bratcheda.org
1695 No patch is needed to preserve the netfilter mark, which will work
1696 with all variants of netfilter.
1698 disable-preserve-miss
1699 This option disables the preservation of the TOS or netfilter
1700 mark. By default, the existing TOS or netfilter mark value of
1701 the response coming from the remote server will be retained
1702 and masked with miss-mark.
1703 NOTE: in the case of a netfilter mark, the mark must be set on
1704 the connection (using the CONNMARK target) not on the packet
1708 Allows you to mask certain bits in the TOS or mark value
1709 received from the remote server, before copying the value to
1710 the TOS sent towards clients.
1711 Default for tos: 0xFF (TOS from server is not changed).
1712 Default for mark: 0xFFFFFFFF (mark from server is not changed).
1714 All of these features require the --enable-zph-qos compilation flag
1715 (enabled by default). Netfilter marking also requires the
1716 libnetfilter_conntrack libraries (--with-netfilter-conntrack) and
1717 libcap 2.09+ (--with-libcap).
1721 NAME: tcp_outgoing_address
1724 LOC: Config.accessList.outgoing_address
1726 Allows you to map requests to different outgoing IP addresses
1727 based on the username or source address of the user making
1730 tcp_outgoing_address ipaddr [[!]aclname] ...
1732 Example where requests from 10.0.0.0/24 will be forwarded
1733 with source address 10.1.0.1, 10.0.2.0/24 forwarded with
1734 source address 10.1.0.2 and the rest will be forwarded with
1735 source address 10.1.0.3.
1737 acl normal_service_net src 10.0.0.0/24
1738 acl good_service_net src 10.0.2.0/24
1739 tcp_outgoing_address 10.1.0.1 normal_service_net
1740 tcp_outgoing_address 10.1.0.2 good_service_net
1741 tcp_outgoing_address 10.1.0.3
1743 Processing proceeds in the order specified, and stops at first fully
1746 Note: The use of this directive using client dependent ACLs is
1747 incompatible with the use of server side persistent connections. To
1748 ensure correct results it is best to set server_persistent_connections
1749 to off when using this directive in such configurations.
1751 Note: The use of this directive to set a local IP on outgoing TCP links
1752 is incompatible with using TPROXY to set client IP out outbound TCP links.
1753 When needing to contact peers use the no-tproxy cache_peer option to
1754 re-enable normal forwarding such as this.
1758 Squid is built with a capability of bridging the IPv4 and IPv6
1760 tcp_outgoing_address as exampled above breaks this bridging by forcing
1761 all outbound traffic through a certain IPv4 which may be on the wrong
1762 side of the IPv4/IPv6 boundary.
1764 To operate with tcp_outgoing_address and keep the bridging benefits
1765 an additional ACL needs to be used which ensures the IPv6-bound traffic
1766 is never forced or permitted out the IPv4 interface.
1768 acl to_ipv6 dst ipv6
1769 tcp_outgoing_address 2002::c001 good_service_net to_ipv6
1770 tcp_outgoing_address 10.1.0.2 good_service_net !to_ipv6
1772 tcp_outgoing_address 2002::beef normal_service_net to_ipv6
1773 tcp_outgoing_address 10.1.0.1 normal_service_net !to_ipv6
1775 tcp_outgoing_address 2002::1 to_ipv6
1776 tcp_outgoing_address 10.1.0.3 !to_ipv6
1779 'dst ipv6' bases its selection assuming DIRECT access.
1780 If peers are used the peername ACL are needed to select outgoing
1781 address which can link to the peer.
1783 'dst ipv6' is a slow ACL. It will only work here if 'dst' is used
1784 previously in the http_access rules to locate the destination IP.
1785 Some more magic may be needed for that:
1786 http_access allow to_ipv6 !all
1787 (meaning, allow if to IPv6 but not from anywhere ;)
1793 -----------------------------------------------------------------------------
1796 NAME: ssl_unclean_shutdown
1800 LOC: Config.SSL.unclean_shutdown
1802 Some browsers (especially MSIE) bugs out on SSL shutdown
1809 LOC: Config.SSL.ssl_engine
1812 The OpenSSL engine to use. You will need to set this if you
1813 would like to use hardware SSL acceleration for example.
1816 NAME: sslproxy_client_certificate
1819 LOC: Config.ssl_client.cert
1822 Client SSL Certificate to use when proxying https:// URLs
1825 NAME: sslproxy_client_key
1828 LOC: Config.ssl_client.key
1831 Client SSL Key to use when proxying https:// URLs
1834 NAME: sslproxy_version
1837 LOC: Config.ssl_client.version
1840 SSL version level to use when proxying https:// URLs
1843 NAME: sslproxy_options
1846 LOC: Config.ssl_client.options
1849 SSL engine options to use when proxying https:// URLs
1851 The most important being:
1853 NO_SSLv2 Disallow the use of SSLv2
1854 NO_SSLv3 Disallow the use of SSLv3
1855 NO_TLSv1 Disallow the use of TLSv1
1857 Always create a new key when using
1858 temporary/ephemeral DH key exchanges
1860 These options vary depending on your SSL engine.
1861 See the OpenSSL SSL_CTX_set_options documentation for a
1862 complete list of possible options.
1865 NAME: sslproxy_cipher
1868 LOC: Config.ssl_client.cipher
1871 SSL cipher list to use when proxying https:// URLs
1873 Colon separated list of supported ciphers.
1876 NAME: sslproxy_cafile
1879 LOC: Config.ssl_client.cafile
1882 file containing CA certificates to use when verifying server
1883 certificates while proxying https:// URLs
1886 NAME: sslproxy_capath
1889 LOC: Config.ssl_client.capath
1892 directory containing CA certificates to use when verifying
1893 server certificates while proxying https:// URLs
1899 LOC: Config.accessList.ssl_bump
1902 This ACL controls which CONNECT requests to an http_port
1903 marked with an sslBump flag are actually "bumped". Please
1904 see the sslBump flag of an http_port option for more details
1905 about decoding proxied SSL connections.
1907 By default, no requests are bumped.
1909 See also: http_port sslBump
1911 This clause only supports fast acl types.
1912 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1915 # Example: Bump all requests except those originating from localhost and
1916 # those going to webax.com or example.com sites.
1918 acl localhost src 127.0.0.1/32
1919 acl broken_sites dstdomain .webax.com
1920 acl broken_sites dstdomain .example.com
1921 ssl_bump deny localhost
1922 ssl_bump deny broken_sites
1926 NAME: sslproxy_flags
1929 LOC: Config.ssl_client.flags
1932 Various flags modifying the use of SSL while proxying https:// URLs:
1933 DONT_VERIFY_PEER Accept certificates that fail verification.
1934 For refined control, see sslproxy_cert_error.
1935 NO_DEFAULT_CA Don't use the default CA list built in
1940 NAME: sslproxy_cert_error
1943 LOC: Config.ssl_client.cert_error
1946 Use this ACL to bypass server certificate validation errors.
1948 For example, the following lines will bypass all validation errors
1949 when talking to servers located at 172.16.0.0/16. All other
1950 validation errors will result in ERR_SECURE_CONNECT_FAIL error.
1952 acl BrokenServersAtTrustedIP dst 172.16.0.0/16
1953 sslproxy_cert_error allow BrokenServersAtTrustedIP
1954 sslproxy_cert_error deny all
1956 This clause only supports fast acl types.
1957 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1958 Using slow acl types may result in server crashes
1960 Without this option, all server certificate validation errors
1961 terminate the transaction. Bypassing validation errors is dangerous
1962 because an error usually implies that the server cannot be trusted and
1963 the connection may be insecure.
1965 See also: sslproxy_flags and DONT_VERIFY_PEER.
1967 Default setting: sslproxy_cert_error deny all
1972 NAME: sslpassword_program
1975 LOC: Config.Program.ssl_password
1978 Specify a program used for entering SSL key passphrases
1979 when using encrypted SSL certificate keys. If not specified
1980 keys must either be unencrypted, or Squid started with the -N
1981 option to allow it to query interactively for the passphrase.
1983 The key file name is given as argument to the program allowing
1984 selection of the right password if you have multiple encrypted
1989 OPTIONS RELATING TO EXTERNAL SSL_CRTD
1990 -----------------------------------------------------------------------------
1993 NAME: sslcrtd_program
1996 DEFAULT: @DEFAULT_SSL_CRTD@ -s @DEFAULT_SSL_DB_DIR@ -M 4MB
1997 LOC: Ssl::TheConfig.ssl_crtd
1999 Specify the location and options of the executable for ssl_crtd process.
2000 @DEFAULT_SSL_CRTD@ program requires -s and -M parameters
2001 For more information use:
2002 @DEFAULT_SSL_CRTD@ -h
2005 NAME: sslcrtd_children
2006 TYPE: HelperChildConfig
2008 DEFAULT: 32 startup=5 idle=1
2009 LOC: Ssl::TheConfig.ssl_crtdChildren
2011 The maximum number of processes spawn to service ssl server.
2012 The maximum this may be safely set to is 32.
2014 The startup= and idle= options allow some measure of skew in your
2019 Sets the minimum number of processes to spawn when Squid
2020 starts or reconfigures. When set to zero the first request will
2021 cause spawning of the first child process to handle it.
2023 Starting too few children temporary slows Squid under load while it
2024 tries to spawn enough additional processes to cope with traffic.
2028 Sets a minimum of how many processes Squid is to try and keep available
2029 at all times. When traffic begins to rise above what the existing
2030 processes can handle this many more will be spawned up to the maximum
2031 configured. A minimum setting of 1 is required.
2033 You must have at least one ssl_crtd process.
2037 OPTIONS WHICH AFFECT THE NEIGHBOR SELECTION ALGORITHM
2038 -----------------------------------------------------------------------------
2046 To specify other caches in a hierarchy, use the format:
2048 cache_peer hostname type http-port icp-port [options]
2053 # hostname type port port options
2054 # -------------------- -------- ----- ----- -----------
2055 cache_peer parent.foo.net parent 3128 3130 default
2056 cache_peer sib1.foo.net sibling 3128 3130 proxy-only
2057 cache_peer sib2.foo.net sibling 3128 3130 proxy-only
2058 cache_peer example.com parent 80 0 no-query default
2059 cache_peer cdn.example.com sibling 3128 0
2061 type: either 'parent', 'sibling', or 'multicast'.
2063 proxy-port: The port number where the peer accept HTTP requests.
2064 For other Squid proxies this is usually 3128
2065 For web servers this is usually 80
2067 icp-port: Used for querying neighbor caches about objects.
2068 Set to 0 if the peer does not support ICP or HTCP.
2069 See ICP and HTCP options below for additional details.
2072 ==== ICP OPTIONS ====
2074 You MUST also set icp_port and icp_access explicitly when using these options.
2075 The defaults will prevent peer traffic using ICP.
2078 no-query Disable ICP queries to this neighbor.
2081 Indicates the named peer is a member of a multicast group.
2082 ICP queries will not be sent directly to the peer, but ICP
2083 replies will be accepted from it.
2085 closest-only Indicates that, for ICP_OP_MISS replies, we'll only forward
2086 CLOSEST_PARENT_MISSes and never FIRST_PARENT_MISSes.
2089 To only send ICP queries to this neighbor infrequently.
2090 This is used to keep the neighbor round trip time updated
2091 and is usually used in conjunction with weighted-round-robin.
2094 ==== HTCP OPTIONS ====
2096 You MUST also set htcp_port and htcp_access explicitly when using these options.
2097 The defaults will prevent peer traffic using HTCP.
2100 htcp Send HTCP, instead of ICP, queries to the neighbor.
2101 You probably also want to set the "icp-port" to 4827
2102 instead of 3130. This directive accepts a comma separated
2103 list of options described below.
2105 htcp=oldsquid Send HTCP to old Squid versions (2.5 or earlier).
2107 htcp=no-clr Send HTCP to the neighbor but without
2108 sending any CLR requests. This cannot be used with
2111 htcp=only-clr Send HTCP to the neighbor but ONLY CLR requests.
2112 This cannot be used with no-clr.
2115 Send HTCP to the neighbor including CLRs but only when
2116 they do not result from PURGE requests.
2119 Forward any HTCP CLR requests this proxy receives to the peer.
2122 ==== PEER SELECTION METHODS ====
2124 The default peer selection method is ICP, with the first responding peer
2125 being used as source. These options can be used for better load balancing.
2128 default This is a parent cache which can be used as a "last-resort"
2129 if a peer cannot be located by any of the peer-selection methods.
2130 If specified more than once, only the first is used.
2132 round-robin Load-Balance parents which should be used in a round-robin
2133 fashion in the absence of any ICP queries.
2134 weight=N can be used to add bias.
2136 weighted-round-robin
2137 Load-Balance parents which should be used in a round-robin
2138 fashion with the frequency of each parent being based on the
2139 round trip time. Closer parents are used more often.
2140 Usually used for background-ping parents.
2141 weight=N can be used to add bias.
2143 carp Load-Balance parents which should be used as a CARP array.
2144 The requests will be distributed among the parents based on the
2145 CARP load balancing hash function based on their weight.
2147 userhash Load-balance parents based on the client proxy_auth or ident username.
2149 sourcehash Load-balance parents based on the client source IP.
2152 To be used only for cache peers of type "multicast".
2153 ALL members of this multicast group have "sibling"
2154 relationship with it, not "parent". This is to a mulicast
2155 group when the requested object would be fetched only from
2156 a "parent" cache, anyway. It's useful, e.g., when
2157 configuring a pool of redundant Squid proxies, being
2158 members of the same multicast group.
2161 ==== PEER SELECTION OPTIONS ====
2163 weight=N use to affect the selection of a peer during any weighted
2164 peer-selection mechanisms.
2165 The weight must be an integer; default is 1,
2166 larger weights are favored more.
2167 This option does not affect parent selection if a peering
2168 protocol is not in use.
2170 basetime=N Specify a base amount to be subtracted from round trip
2172 It is subtracted before division by weight in calculating
2173 which parent to fectch from. If the rtt is less than the
2174 base time the rtt is set to a minimal value.
2176 ttl=N Specify a TTL to use when sending multicast ICP queries
2178 Only useful when sending to a multicast group.
2179 Because we don't accept ICP replies from random
2180 hosts, you must configure other group members as
2181 peers with the 'multicast-responder' option.
2183 no-delay To prevent access to this neighbor from influencing the
2186 digest-url=URL Tell Squid to fetch the cache digest (if digests are
2187 enabled) for this host from the specified URL rather
2188 than the Squid default location.
2191 ==== ACCELERATOR / REVERSE-PROXY OPTIONS ====
2193 originserver Causes this parent to be contacted as an origin server.
2194 Meant to be used in accelerator setups when the peer
2198 Set the Host header of requests forwarded to this peer.
2199 Useful in accelerator setups where the server (peer)
2200 expects a certain domain name but clients may request
2201 others. ie example.com or www.example.com
2203 no-digest Disable request of cache digests.
2206 Disables requesting ICMP RTT database (NetDB).
2209 ==== AUTHENTICATION OPTIONS ====
2212 If this is a personal/workgroup proxy and your parent
2213 requires proxy authentication.
2215 Note: The string can include URL escapes (i.e. %20 for
2216 spaces). This also means % must be written as %%.
2219 Send login details received from client to this peer.
2220 Both Proxy- and WWW-Authorization headers are passed
2221 without alteration to the peer.
2222 Authentication is not required by Squid for this to work.
2224 Note: This will pass any form of authentication but
2225 only Basic auth will work through a proxy unless the
2226 connection-auth options are also used.
2228 login=PASS Send login details received from client to this peer.
2229 Authentication is not required by this option.
2231 If there are no client-provided authentication headers
2232 to pass on, but username and password are available
2233 from an external ACL user= and password= result tags
2234 they may be sent instead.
2236 Note: To combine this with proxy_auth both proxies must
2237 share the same user database as HTTP only allows for
2238 a single login (one for proxy, one for origin server).
2239 Also be warned this will expose your users proxy
2240 password to the peer. USE WITH CAUTION
2243 Send the username to the upstream cache, but with a
2244 fixed password. This is meant to be used when the peer
2245 is in another administrative domain, but it is still
2246 needed to identify each user.
2247 The star can optionally be followed by some extra
2248 information which is added to the username. This can
2249 be used to identify this proxy to the peer, similar to
2250 the login=username:password option above.
2253 If this is a personal/workgroup proxy and your parent
2254 requires a secure proxy authentication.
2255 The first principal from the default keytab or defined by
2256 the environment variable KRB5_KTNAME will be used.
2258 login=NEGOTIATE:principal_name
2259 If this is a personal/workgroup proxy and your parent
2260 requires a secure proxy authentication.
2261 The principal principal_name from the default keytab or
2262 defined by the environment variable KRB5_KTNAME will be
2265 connection-auth=on|off
2266 Tell Squid that this peer does or not support Microsoft
2267 connection oriented authentication, and any such
2268 challenges received from there should be ignored.
2269 Default is auto to automatically determine the status
2273 ==== SSL / HTTPS / TLS OPTIONS ====
2275 ssl Encrypt connections to this peer with SSL/TLS.
2277 sslcert=/path/to/ssl/certificate
2278 A client SSL certificate to use when connecting to
2281 sslkey=/path/to/ssl/key
2282 The private SSL key corresponding to sslcert above.
2283 If 'sslkey' is not specified 'sslcert' is assumed to
2284 reference a combined file containing both the
2285 certificate and the key.
2288 The SSL version to use when connecting to this peer
2289 1 = automatic (default)
2294 sslcipher=... The list of valid SSL ciphers to use when connecting
2297 ssloptions=... Specify various SSL engine options:
2298 NO_SSLv2 Disallow the use of SSLv2
2299 NO_SSLv3 Disallow the use of SSLv3
2300 NO_TLSv1 Disallow the use of TLSv1
2301 See src/ssl_support.c or the OpenSSL documentation for
2302 a more complete list.
2304 sslcafile=... A file containing additional CA certificates to use
2305 when verifying the peer certificate.
2307 sslcapath=... A directory containing additional CA certificates to
2308 use when verifying the peer certificate.
2310 sslcrlfile=... A certificate revocation list file to use when
2311 verifying the peer certificate.
2313 sslflags=... Specify various flags modifying the SSL implementation:
2316 Accept certificates even if they fail to
2319 Don't use the default CA list built in
2322 Don't verify the peer certificate
2323 matches the server name
2325 ssldomain= The peer name as advertised in it's certificate.
2326 Used for verifying the correctness of the received peer
2327 certificate. If not specified the peer hostname will be
2331 Enable the "Front-End-Https: On" header needed when
2332 using Squid as a SSL frontend in front of Microsoft OWA.
2333 See MS KB document Q307347 for details on this header.
2334 If set to auto the header will only be added if the
2335 request is forwarded as a https:// URL.
2338 ==== GENERAL OPTIONS ====
2341 A peer-specific connect timeout.
2342 Also see the peer_connect_timeout directive.
2344 connect-fail-limit=N
2345 How many times connecting to a peer must fail before
2346 it is marked as down. Default is 10.
2348 allow-miss Disable Squid's use of only-if-cached when forwarding
2349 requests to siblings. This is primarily useful when
2350 icp_hit_stale is used by the sibling. To extensive use
2351 of this option may result in forwarding loops, and you
2352 should avoid having two-way peerings with this option.
2353 For example to deny peer usage on requests from peer
2354 by denying cache_peer_access if the source is a peer.
2356 max-conn=N Limit the amount of connections Squid may open to this
2359 name=xxx Unique name for the peer.
2360 Required if you have multiple peers on the same host
2361 but different ports.
2362 This name can be used in cache_peer_access and similar
2363 directives to dentify the peer.
2364 Can be used by outgoing access controls through the
2367 no-tproxy Do not use the client-spoof TPROXY support when forwarding
2368 requests to this peer. Use normal address selection instead.
2370 proxy-only objects fetched from the peer will not be stored locally.
2374 NAME: cache_peer_domain cache_host_domain
2379 Use to limit the domains for which a neighbor cache will be
2382 cache_peer_domain cache-host domain [domain ...]
2383 cache_peer_domain cache-host !domain
2385 For example, specifying
2387 cache_peer_domain parent.foo.net .edu
2389 has the effect such that UDP query packets are sent to
2390 'bigserver' only when the requested object exists on a
2391 server in the .edu domain. Prefixing the domainname
2392 with '!' means the cache will be queried for objects
2395 NOTE: * Any number of domains may be given for a cache-host,
2396 either on the same or separate lines.
2397 * When multiple domains are given for a particular
2398 cache-host, the first matched domain is applied.
2399 * Cache hosts with no domain restrictions are queried
2401 * There are no defaults.
2402 * There is also a 'cache_peer_access' tag in the ACL
2406 NAME: cache_peer_access
2411 Similar to 'cache_peer_domain' but provides more flexibility by
2414 cache_peer_access cache-host allow|deny [!]aclname ...
2416 The syntax is identical to 'http_access' and the other lists of
2417 ACL elements. See the comments for 'http_access' below, or
2418 the Squid FAQ (http://wiki.squid-cache.org/SquidFaq/SquidAcl).
2421 NAME: neighbor_type_domain
2422 TYPE: hostdomaintype
2426 usage: neighbor_type_domain neighbor parent|sibling domain domain ...
2428 Modifying the neighbor type for specific domains is now
2429 possible. You can treat some domains differently than the
2430 default neighbor type specified on the 'cache_peer' line.
2431 Normally it should only be necessary to list domains which
2432 should be treated differently because the default neighbor type
2433 applies for hostnames which do not match domains listed here.
2436 cache_peer cache.foo.org parent 3128 3130
2437 neighbor_type_domain cache.foo.org sibling .com .net
2438 neighbor_type_domain cache.foo.org sibling .au .de
2441 NAME: dead_peer_timeout
2445 LOC: Config.Timeout.deadPeer
2447 This controls how long Squid waits to declare a peer cache
2448 as "dead." If there are no ICP replies received in this
2449 amount of time, Squid will declare the peer dead and not
2450 expect to receive any further ICP replies. However, it
2451 continues to send ICP queries, and will mark the peer as
2452 alive upon receipt of the first subsequent ICP reply.
2454 This timeout also affects when Squid expects to receive ICP
2455 replies from peers. If more than 'dead_peer' seconds have
2456 passed since the last ICP reply was received, Squid will not
2457 expect to receive an ICP reply on the next query. Thus, if
2458 your time between requests is greater than this timeout, you
2459 will see a lot of requests sent DIRECT to origin servers
2460 instead of to your parents.
2463 NAME: forward_max_tries
2466 LOC: Config.forward_max_tries
2468 Controls how many different forward paths Squid will try
2469 before giving up. See also forward_timeout.
2471 NOTE: connect_retries (default: none) can make each of these
2472 possible forwarding paths be tried multiple times.
2475 NAME: hierarchy_stoplist
2478 LOC: Config.hierarchy_stoplist
2480 A list of words which, if found in a URL, cause the object to
2481 be handled directly by this cache. In other words, use this
2482 to not query neighbor caches for certain objects. You may
2483 list this option multiple times.
2484 Note: never_direct overrides this option.
2487 # We recommend you to use at least the following line.
2488 hierarchy_stoplist cgi-bin ?
2493 MEMORY CACHE OPTIONS
2494 -----------------------------------------------------------------------------
2501 LOC: Config.memMaxSize
2503 NOTE: THIS PARAMETER DOES NOT SPECIFY THE MAXIMUM PROCESS SIZE.
2504 IT ONLY PLACES A LIMIT ON HOW MUCH ADDITIONAL MEMORY SQUID WILL
2505 USE AS A MEMORY CACHE OF OBJECTS. SQUID USES MEMORY FOR OTHER
2506 THINGS AS WELL. SEE THE SQUID FAQ SECTION 8 FOR DETAILS.
2508 'cache_mem' specifies the ideal amount of memory to be used
2510 * In-Transit objects
2512 * Negative-Cached objects
2514 Data for these objects are stored in 4 KB blocks. This
2515 parameter specifies the ideal upper limit on the total size of
2516 4 KB blocks allocated. In-Transit objects take the highest
2519 In-transit objects have priority over the others. When
2520 additional space is needed for incoming data, negative-cached
2521 and hot objects will be released. In other words, the
2522 negative-cached and hot objects will fill up any unused space
2523 not needed for in-transit objects.
2525 If circumstances require, this limit will be exceeded.
2526 Specifically, if your incoming request rate requires more than
2527 'cache_mem' of memory to hold in-transit objects, Squid will
2528 exceed this limit to satisfy the new requests. When the load
2529 decreases, blocks will be freed until the high-water mark is
2530 reached. Thereafter, blocks will be used to store hot
2534 NAME: maximum_object_size_in_memory
2538 LOC: Config.Store.maxInMemObjSize
2540 Objects greater than this size will not be attempted to kept in
2541 the memory cache. This should be set high enough to keep objects
2542 accessed frequently in memory to improve performance whilst low
2543 enough to keep larger objects from hoarding cache_mem.
2546 NAME: memory_cache_mode
2551 Controls which objects to keep in the memory cache (cache_mem)
2553 always Keep most recently fetched objects in memory (default)
2555 disk Only disk cache hits are kept in memory, which means
2556 an object must first be cached on disk and then hit
2557 a second time before cached in memory.
2559 network Only objects fetched from network is kept in memory
2562 NAME: memory_replacement_policy
2564 LOC: Config.memPolicy
2567 The memory replacement policy parameter determines which
2568 objects are purged from memory when memory space is needed.
2570 See cache_replacement_policy for details.
2575 -----------------------------------------------------------------------------
2578 NAME: cache_replacement_policy
2580 LOC: Config.replPolicy
2583 The cache replacement policy parameter determines which
2584 objects are evicted (replaced) when disk space is needed.
2586 lru : Squid's original list based LRU policy
2587 heap GDSF : Greedy-Dual Size Frequency
2588 heap LFUDA: Least Frequently Used with Dynamic Aging
2589 heap LRU : LRU policy implemented using a heap
2591 Applies to any cache_dir lines listed below this.
2593 The LRU policies keeps recently referenced objects.
2595 The heap GDSF policy optimizes object hit rate by keeping smaller
2596 popular objects in cache so it has a better chance of getting a
2597 hit. It achieves a lower byte hit rate than LFUDA though since
2598 it evicts larger (possibly popular) objects.
2600 The heap LFUDA policy keeps popular objects in cache regardless of
2601 their size and thus optimizes byte hit rate at the expense of
2602 hit rate since one large, popular object will prevent many
2603 smaller, slightly less popular objects from being cached.
2605 Both policies utilize a dynamic aging mechanism that prevents
2606 cache pollution that can otherwise occur with frequency-based
2607 replacement policies.
2609 NOTE: if using the LFUDA replacement policy you should increase
2610 the value of maximum_object_size above its default of 4096 KB to
2611 to maximize the potential byte hit rate improvement of LFUDA.
2613 For more information about the GDSF and LFUDA cache replacement
2614 policies see http://www.hpl.hp.com/techreports/1999/HPL-1999-69.html
2615 and http://fog.hpl.external.hp.com/techreports/98/HPL-98-173.html.
2621 LOC: Config.cacheSwap
2625 cache_dir Type Directory-Name Fs-specific-data [options]
2627 You can specify multiple cache_dir lines to spread the
2628 cache among different disk partitions.
2630 Type specifies the kind of storage system to use. Only "ufs"
2631 is built by default. To enable any of the other storage systems
2632 see the --enable-storeio configure option.
2634 'Directory' is a top-level directory where cache swap
2635 files will be stored. If you want to use an entire disk
2636 for caching, this can be the mount-point directory.
2637 The directory must exist and be writable by the Squid
2638 process. Squid will NOT create this directory for you.
2640 In SMP configurations, cache_dir must not precede the workers option
2641 and should use configuration macros or conditionals to give each
2642 worker interested in disk caching a dedicated cache directory.
2646 "ufs" is the old well-known Squid storage format that has always
2649 cache_dir ufs Directory-Name Mbytes L1 L2 [options]
2651 'Mbytes' is the amount of disk space (MB) to use under this
2652 directory. The default is 100 MB. Change this to suit your
2653 configuration. Do NOT put the size of your disk drive here.
2654 Instead, if you want Squid to use the entire disk drive,
2655 subtract 20% and use that value.
2657 'L1' is the number of first-level subdirectories which
2658 will be created under the 'Directory'. The default is 16.
2660 'L2' is the number of second-level subdirectories which
2661 will be created under each first-level directory. The default
2664 The aufs store type:
2666 "aufs" uses the same storage format as "ufs", utilizing
2667 POSIX-threads to avoid blocking the main Squid process on
2668 disk-I/O. This was formerly known in Squid as async-io.
2670 cache_dir aufs Directory-Name Mbytes L1 L2 [options]
2672 see argument descriptions under ufs above
2674 The diskd store type:
2676 "diskd" uses the same storage format as "ufs", utilizing a
2677 separate process to avoid blocking the main Squid process on
2680 cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n]
2682 see argument descriptions under ufs above
2684 Q1 specifies the number of unacknowledged I/O requests when Squid
2685 stops opening new files. If this many messages are in the queues,
2686 Squid won't open new files. Default is 64
2688 Q2 specifies the number of unacknowledged messages when Squid
2689 starts blocking. If this many messages are in the queues,
2690 Squid blocks until it receives some replies. Default is 72
2692 When Q1 < Q2 (the default), the cache directory is optimized
2693 for lower response time at the expense of a decrease in hit
2694 ratio. If Q1 > Q2, the cache directory is optimized for
2695 higher hit ratio at the expense of an increase in response
2698 The coss store type:
2700 NP: COSS filesystem in Squid-3 has been deemed too unstable for
2701 production use and has thus been removed from this release.
2702 We hope that it can be made usable again soon.
2704 block-size=n defines the "block size" for COSS cache_dir's.
2705 Squid uses file numbers as block numbers. Since file numbers
2706 are limited to 24 bits, the block size determines the maximum
2707 size of the COSS partition. The default is 512 bytes, which
2708 leads to a maximum cache_dir size of 512<<24, or 8 GB. Note
2709 you should not change the coss block size after Squid
2710 has written some objects to the cache_dir.
2712 The coss file store has changed from 2.5. Now it uses a file
2713 called 'stripe' in the directory names in the config - and
2714 this will be created by squid -z.
2718 no-store, no new objects should be stored to this cache_dir
2720 max-size=n, refers to the max object size in bytes this cache_dir
2721 supports. It is used to select the cache_dir to store the object.
2722 Note: To make optimal use of the max-size limits you should order
2723 the cache_dir lines with the smallest max-size value first and the
2724 ones with no max-size specification last.
2726 Note for coss, max-size must be less than COSS_MEMBUF_SZ,
2727 which can be changed with the --with-coss-membuf-size=N configure
2731 # Uncomment and adjust the following to add a disk cache directory.
2732 #cache_dir ufs @DEFAULT_SWAP_DIR@ 100 16 256
2736 NAME: store_dir_select_algorithm
2738 LOC: Config.store_dir_select_algorithm
2741 Set this to 'round-robin' as an alternative.
2744 NAME: max_open_disk_fds
2746 LOC: Config.max_open_disk_fds
2749 To avoid having disk as the I/O bottleneck Squid can optionally
2750 bypass the on-disk cache if more than this amount of disk file
2751 descriptors are open.
2753 A value of 0 indicates no limit.
2756 NAME: minimum_object_size
2760 LOC: Config.Store.minObjectSize
2762 Objects smaller than this size will NOT be saved on disk. The
2763 value is specified in kilobytes, and the default is 0 KB, which
2764 means there is no minimum.
2767 NAME: maximum_object_size
2771 LOC: Config.Store.maxObjectSize
2773 Objects larger than this size will NOT be saved on disk. The
2774 value is specified in kilobytes, and the default is 4MB. If
2775 you wish to get a high BYTES hit ratio, you should probably
2776 increase this (one 32 MB object hit counts for 3200 10KB
2777 hits). If you wish to increase speed more than your want to
2778 save bandwidth you should leave this low.
2780 NOTE: if using the LFUDA replacement policy you should increase
2781 this value to maximize the byte hit rate improvement of LFUDA!
2782 See replacement_policy below for a discussion of this policy.
2785 NAME: cache_swap_low
2786 COMMENT: (percent, 0-100)
2789 LOC: Config.Swap.lowWaterMark
2792 NAME: cache_swap_high
2793 COMMENT: (percent, 0-100)
2796 LOC: Config.Swap.highWaterMark
2799 The low- and high-water marks for cache object replacement.
2800 Replacement begins when the swap (disk) usage is above the
2801 low-water mark and attempts to maintain utilization near the
2802 low-water mark. As swap utilization gets close to high-water
2803 mark object eviction becomes more aggressive. If utilization is
2804 close to the low-water mark less replacement is done each time.
2806 Defaults are 90% and 95%. If you have a large cache, 5% could be
2807 hundreds of MB. If this is the case you may wish to set these
2808 numbers closer together.
2813 -----------------------------------------------------------------------------
2818 LOC: Config.Log.logformats
2823 logformat <name> <format specification>
2825 Defines an access log format.
2827 The <format specification> is a string with embedded % format codes
2829 % format codes all follow the same basic structure where all but
2830 the formatcode is optional. Output strings are automatically escaped
2831 as required according to their context and the output format
2832 modifiers are usually not needed, but can be specified if an explicit
2833 output format is desired.
2835 % ["|[|'|#] [-] [[0]width] [{argument}] formatcode
2837 " output in quoted string format
2838 [ output in squid text log format as used by log_mime_hdrs
2839 # output in URL quoted format
2843 width field width. If starting with 0 the
2844 output is zero padded
2845 {arg} argument such as header name etc
2849 % a literal % character
2850 sn Unique sequence number per log line entry
2851 err_code The ID of an error response served by Squid or
2852 a similar internal error identifier.
2853 err_detail Additional err_code-dependent error information.
2855 Connection related format codes:
2857 >a Client source IP address
2859 >p Client source port
2860 <A Server IP address or peer name
2861 la Local IP address (http_port)
2862 lp Local port number (http_port)
2863 <lp Local port number of the last server or peer connection
2865 Time related format codes:
2867 ts Seconds since epoch
2868 tu subsecond time (milliseconds)
2869 tl Local time. Optional strftime format argument
2870 default %d/%b/%Y:%H:%M:%S %z
2871 tg GMT time. Optional strftime format argument
2872 default %d/%b/%Y:%H:%M:%S %z
2873 tr Response time (milliseconds)
2874 dt Total time spent making DNS lookups (milliseconds)
2876 HTTP cache related format codes:
2878 [http::]>h Original request header. Optional header name argument
2879 on the format header[:[separator]element]
2880 [http::]>ha The HTTP request headers after adaptation and redirection.
2881 Optional header name argument as for >h
2882 [http::]<h Reply header. Optional header name argument
2884 [http::]un User name
2885 [http::]ul User name from authentication
2886 [http::]ui User name from ident
2887 [http::]us User name from SSL
2888 [http::]ue User name from external acl helper
2889 [http::]>Hs HTTP status code sent to the client
2890 [http::]<Hs HTTP status code received from the next hop
2891 [http::]<bs Number of HTTP-equivalent message body bytes
2892 received from the next hop, excluding chunked
2893 transfer encoding and control messages.
2894 Generated FTP/Gopher listings are treated as
2896 [http::]Ss Squid request status (TCP_MISS etc)
2897 [http::]Sh Squid hierarchy status (DEFAULT_PARENT etc)
2898 [http::]mt MIME content type
2899 [http::]rm Request method (GET/POST etc)
2900 [http::]ru Request URL
2901 [http::]rp Request URL-Path excluding hostname
2902 [http::]rv Request protocol version
2903 [http::]et Tag returned by external acl
2904 [http::]ea Log string returned by external acl
2905 [http::]<st Sent reply size including HTTP headers
2906 [http::]>st Received request size including HTTP headers. In the
2907 case of chunked requests the chunked encoding metadata
2909 [http::]>sh Received HTTP request headers size
2910 [http::]<sh Sent HTTP reply headers size
2911 [http::]st Request+Reply size including HTTP headers
2912 [http::]<sH Reply high offset sent
2913 [http::]<sS Upstream object size
2914 [http::]<pt Peer response time in milliseconds. The timer starts
2915 when the last request byte is sent to the next hop
2916 and stops when the last response byte is received.
2917 [http::]<tt Total server-side time in milliseconds. The timer
2918 starts with the first connect request (or write I/O)
2919 sent to the first selected peer. The timer stops
2920 with the last I/O with the last peer.
2922 If ICAP is enabled, the following two codes become available (as
2923 well as ICAP log codes documented with the icap_log option):
2925 icap::tt Total ICAP processing time for the HTTP
2926 transaction. The timer ticks when ICAP
2927 ACLs are checked and when ICAP
2928 transaction is in progress.
2930 icap::<last_h The header of the last ICAP response
2931 related to the HTTP transaction. Like
2932 <h, accepts an optional header name
2933 argument. Will not change semantics
2934 when multiple ICAP transactions per HTTP
2935 transaction are supported.
2937 If adaptation is enabled the following two codes become available:
2939 adapt::sum_trs Summed adaptation transaction response
2940 times recorded as a comma-separated list in
2941 the order of transaction start time. Each time
2942 value is recorded as an integer number,
2943 representing response time of one or more
2944 adaptation (ICAP or eCAP) transaction in
2945 milliseconds. When a failed transaction is
2946 being retried or repeated, its time is not
2947 logged individually but added to the
2948 replacement (next) transaction. See also:
2951 adapt::all_trs All adaptation transaction response times.
2952 Same as adaptation_strs but response times of
2953 individual transactions are never added
2954 together. Instead, all transaction response
2955 times are recorded individually.
2957 You can prefix adapt::*_trs format codes with adaptation
2958 service name in curly braces to record response time(s) specific
2959 to that service. For example: %{my_service}adapt::sum_trs
2961 The default formats available (which do not need re-defining) are:
2963 logformat squid %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %un %Sh/%<A %mt
2964 logformat squidmime %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %un %Sh/%<A %mt [%>h] [%<h]
2965 logformat common %>a %ui %un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st %Ss:%Sh
2966 logformat combined %>a %ui %un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
2969 NAME: access_log cache_access_log
2971 LOC: Config.Log.accesslogs
2972 DEFAULT_IF_NONE: daemon:@DEFAULT_ACCESS_LOG@ squid
2974 These files log client request activities. Has a line every HTTP or
2975 ICP request. The format is:
2976 access_log <module>:<place> [<logformat name> [acl acl ...]]
2977 access_log none [acl acl ...]]
2979 Will log to the specified module:place using the specified format (which
2980 must be defined in a logformat directive) those entries which match
2981 ALL the acl's specified (which must be defined in acl clauses).
2982 If no acl is specified, all requests will be logged to this destination.
2984 ===== Modules Currently available =====
2986 none Do not log any requests matching these ACL.
2987 Do not specify Place or logformat name.
2989 stdio Write each log line to disk immediately at the completion of
2991 Place: the filename and path to be written.
2993 daemon Very similar to stdio. But instead of writing to disk the log
2994 line is passed to a daemon helper for asychronous handling instead.
2995 Place: varies depending on the daemon.
2997 log_file_daemon Place: the file name and path to be written.
2999 syslog To log each request via syslog facility.
3000 Place: The syslog facility and priority level for these entries.
3001 Place Format: facility.priority
3003 where facility could be any of:
3004 authpriv, daemon, local0 ... local7 or user.
3006 And priority could be any of:
3007 err, warning, notice, info, debug.
3009 udp To send each log line as text data to a UDP receiver.
3010 Place: The destination host name or IP and port.
3011 Place Format: \\host:port
3013 tcp To send each log line as text data to a TCP receiver.
3014 Place: The destination host name or IP and port.
3015 Place Format: \\host:port
3018 access_log daemon:@DEFAULT_ACCESS_LOG@ squid
3024 LOC: Config.Log.icaplogs
3027 ICAP log files record ICAP transaction summaries, one line per
3030 The icap_log option format is:
3031 icap_log <filepath> [<logformat name> [acl acl ...]]
3032 icap_log none [acl acl ...]]
3034 Please see access_log option documentation for details. The two
3035 kinds of logs share the overall configuration approach and many
3038 ICAP processing of a single HTTP message or transaction may
3039 require multiple ICAP transactions. In such cases, multiple
3040 ICAP transaction log lines will correspond to a single access
3043 ICAP log uses logformat codes that make sense for an ICAP
3044 transaction. Header-related codes are applied to the HTTP header
3045 embedded in an ICAP server response, with the following caveats:
3046 For REQMOD, there is no HTTP response header unless the ICAP
3047 server performed request satisfaction. For RESPMOD, the HTTP
3048 request header is the header sent to the ICAP server. For
3049 OPTIONS, there are no HTTP headers.
3051 The following format codes are also available for ICAP logs:
3053 icap::<A ICAP server IP address. Similar to <A.
3055 icap::<service_name ICAP service name from the icap_service
3056 option in Squid configuration file.
3058 icap::ru ICAP Request-URI. Similar to ru.
3060 icap::rm ICAP request method (REQMOD, RESPMOD, or
3061 OPTIONS). Similar to existing rm.
3063 icap::>st Bytes sent to the ICAP server (TCP payload
3064 only; i.e., what Squid writes to the socket).
3066 icap::<st Bytes received from the ICAP server (TCP
3067 payload only; i.e., what Squid reads from
3070 icap::<bs Number of message body bytes received from the
3071 ICAP server. ICAP message body, if any, usually
3072 includes encapsulated HTTP message headers and
3073 possibly encapsulated HTTP message body. The
3074 HTTP body part is dechunked before its size is
3077 icap::tr Transaction response time (in
3078 milliseconds). The timer starts when
3079 the ICAP transaction is created and
3080 stops when the transaction is completed.
3083 icap::tio Transaction I/O time (in milliseconds). The
3084 timer starts when the first ICAP request
3085 byte is scheduled for sending. The timers
3086 stops when the last byte of the ICAP response
3089 icap::to Transaction outcome: ICAP_ERR* for all
3090 transaction errors, ICAP_OPT for OPTION
3091 transactions, ICAP_ECHO for 204
3092 responses, ICAP_MOD for message
3093 modification, and ICAP_SAT for request
3094 satisfaction. Similar to Ss.
3096 icap::Hs ICAP response status code. Similar to Hs.
3098 icap::>h ICAP request header(s). Similar to >h.
3100 icap::<h ICAP response header(s). Similar to <h.
3102 The default ICAP log format, which can be used without an explicit
3103 definition, is called icap_squid:
3105 logformat icap_squid %ts.%03tu %6icap::tr %>a %icap::to/%03icap::Hs %icap::<size %icap::rm %icap::ru% %un -/%icap::<A -
3107 See also: logformat, log_icap, and %icap::<last_h
3110 NAME: logfile_daemon
3112 DEFAULT: @DEFAULT_LOGFILED@
3113 LOC: Log::TheConfig.logfile_daemon
3115 Specify the path to the logfile-writing daemon. This daemon is
3116 used to write the access and store logs, if configured.
3118 Squid sends a number of commands to the log daemon:
3119 L<data>\n - logfile data
3124 r<n>\n - set rotate count to <n>
3125 b<n>\n - 1 = buffer output, 0 = don't buffer output
3127 No responses is expected.
3132 LOC: Config.accessList.log
3134 COMMENT: allow|deny acl acl...
3136 This options allows you to control which requests gets logged
3137 to access.log (see access_log directive). Requests denied for
3138 logging will also not be accounted for in performance counters.
3140 This clause only supports fast acl types.
3141 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
3147 LOC: Config.accessList.icap
3150 This options allows you to control which requests get logged
3151 to icap.log. See the icap_log directive for ICAP log details.
3154 NAME: cache_store_log
3157 LOC: Config.Log.store
3159 Logs the activities of the storage manager. Shows which
3160 objects are ejected from the cache, and which objects are
3161 saved and for how long. To disable, enter "none" or remove the line.
3162 There are not really utilities to analyze this data, so you can safely
3166 cache_store_log @DEFAULT_STORE_LOG@
3169 NAME: cache_swap_state cache_swap_log
3171 LOC: Config.Log.swap
3174 Location for the cache "swap.state" file. This index file holds
3175 the metadata of objects saved on disk. It is used to rebuild
3176 the cache during startup. Normally this file resides in each
3177 'cache_dir' directory, but you may specify an alternate
3178 pathname here. Note you must give a full filename, not just
3179 a directory. Since this is the index for the whole object
3180 list you CANNOT periodically rotate it!
3182 If %s can be used in the file name it will be replaced with a
3183 a representation of the cache_dir name where each / is replaced
3184 with '.'. This is needed to allow adding/removing cache_dir
3185 lines when cache_swap_log is being used.
3187 If have more than one 'cache_dir', and %s is not used in the name
3188 these swap logs will have names such as:
3194 The numbered extension (which is added automatically)
3195 corresponds to the order of the 'cache_dir' lines in this
3196 configuration file. If you change the order of the 'cache_dir'
3197 lines in this file, these index files will NOT correspond to
3198 the correct 'cache_dir' entry (unless you manually rename
3199 them). We recommend you do NOT use this option. It is
3200 better to keep these index files in each 'cache_dir' directory.
3203 NAME: logfile_rotate
3206 LOC: Config.Log.rotateNumber
3208 Specifies the number of logfile rotations to make when you
3209 type 'squid -k rotate'. The default is 10, which will rotate
3210 with extensions 0 through 9. Setting logfile_rotate to 0 will
3211 disable the file name rotation, but the logfiles are still closed
3212 and re-opened. This will enable you to rename the logfiles
3213 yourself just before sending the rotate signal.
3215 Note, the 'squid -k rotate' command normally sends a USR1
3216 signal to the running squid process. In certain situations
3217 (e.g. on Linux with Async I/O), USR1 is used for other
3218 purposes, so -k rotate uses another signal. It is best to get
3219 in the habit of using 'squid -k rotate' instead of 'kill -USR1
3222 Note, from Squid-3.1 this option has no effect on the cache.log,
3223 that log can be rotated separately by using debug_options
3226 NAME: emulate_httpd_log
3230 LOC: Config.onoff.common_log
3232 The Cache can emulate the log file format which many 'httpd'
3233 programs use. To disable/enable this emulation, set
3234 emulate_httpd_log to 'off' or 'on'. The default
3235 is to use the native log format since it includes useful
3236 information Squid-specific log analyzers use.
3239 NAME: log_ip_on_direct
3243 LOC: Config.onoff.log_ip_on_direct
3245 Log the destination IP address in the hierarchy log tag when going
3246 direct. Earlier Squid versions logged the hostname here. If you
3247 prefer the old way set this to off.
3252 DEFAULT: @DEFAULT_MIME_TABLE@
3253 LOC: Config.mimeTablePathname
3255 Pathname to Squid's MIME table. You shouldn't need to change
3256 this, but the default file contains examples and formatting
3257 information if you do.
3263 LOC: Config.onoff.log_mime_hdrs
3266 The Cache can record both the request and the response MIME
3267 headers for each HTTP transaction. The headers are encoded
3268 safely and will appear as two bracketed fields at the end of
3269 the access log (for either the native or httpd-emulated log
3270 formats). To enable this logging set log_mime_hdrs to 'on'.
3275 LOC: Config.Log.useragent
3277 IFDEF: USE_USERAGENT_LOG
3279 Squid will write the User-Agent field from HTTP requests
3280 to the filename specified here. By default useragent_log
3284 NAME: referer_log referrer_log
3286 LOC: Config.Log.referer
3288 IFDEF: USE_REFERER_LOG
3290 Squid will write the Referer field from HTTP requests to the
3291 filename specified here. By default referer_log is disabled.
3292 Note that "referer" is actually a misspelling of "referrer"
3293 however the misspelt version has been accepted into the HTTP RFCs
3299 DEFAULT: @DEFAULT_PID_FILE@
3300 LOC: Config.pidFilename
3302 A filename to write the process-id to. To disable, enter "none".
3308 Remove this option from your config. To log FQDN use %>A in the log format.
3311 NAME: client_netmask
3313 LOC: Config.Addrs.client_netmask
3316 A netmask for client addresses in logfiles and cachemgr output.
3317 Change this to protect the privacy of your cache clients.
3318 A netmask of 255.255.255.0 will log all IP's in that range with
3319 the last digit set to '0'.
3326 LOC: Config.Log.forward
3328 Logs the server-side requests.
3330 This is currently work in progress.
3333 NAME: strip_query_terms
3335 LOC: Config.onoff.strip_query_terms
3338 By default, Squid strips query terms from requested URLs before
3339 logging. This protects your user's privacy.
3346 LOC: Config.onoff.buffered_logs
3348 cache.log log file is written with stdio functions, and as such
3349 it can be buffered or unbuffered. By default it will be unbuffered.
3350 Buffering it can speed up the writing slightly (though you are
3351 unlikely to need to worry unless you run with tons of debugging
3352 enabled in which case performance will suffer badly anyway..).
3355 NAME: netdb_filename
3357 DEFAULT: @DEFAULT_NETDB_FILE@
3358 LOC: Config.netdbFilename
3361 A filename where Squid stores it's netdb state between restarts.
3362 To disable, enter "none".
3366 OPTIONS FOR TROUBLESHOOTING
3367 -----------------------------------------------------------------------------
3372 DEFAULT_IF_NONE: @DEFAULT_CACHE_LOG@
3373 LOC: Debug::cache_log
3375 Cache logging file. This is where general information about
3376 your cache's behavior goes. You can increase the amount of data
3377 logged to this file and how often its rotated with "debug_options"
3383 LOC: Debug::debugOptions
3385 Logging options are set as section,level where each source file
3386 is assigned a unique section. Lower levels result in less
3387 output, Full debugging (level 9) can result in a very large
3388 log file, so be careful.
3390 The magic word "ALL" sets debugging levels for all sections.
3391 We recommend normally running with "ALL,1".
3393 The rotate=N option can be used to keep more or less of these logs
3394 than would otherwise be kept by logfile_rotate.
3395 For most uses a single log should be enough to monitor current
3396 events affecting Squid.
3401 LOC: Config.coredump_dir
3402 DEFAULT_IF_NONE: none
3404 By default Squid leaves core files in the directory from where
3405 it was started. If you set 'coredump_dir' to a directory
3406 that exists, Squid will chdir() to that directory at startup
3407 and coredump files will be left there.
3411 # Leave coredumps in the first cache dir
3412 coredump_dir @DEFAULT_SWAP_DIR@
3418 OPTIONS FOR FTP GATEWAYING
3419 -----------------------------------------------------------------------------
3425 LOC: Config.Ftp.anon_user
3427 If you want the anonymous login password to be more informative
3428 (and enable the use of picky ftp servers), set this to something
3429 reasonable for your domain, like wwwuser@somewhere.net
3431 The reason why this is domainless by default is the
3432 request can be made on the behalf of a user in any domain,
3433 depending on how the cache is used.
3434 Some ftp server also validate the email address is valid
3435 (for example perl.com).
3441 LOC: Config.Ftp.passive
3443 If your firewall does not allow Squid to use passive
3444 connections, turn off this option.
3446 Use of ftp_epsv_all option requires this to be ON.
3452 LOC: Config.Ftp.epsv_all
3454 FTP Protocol extensions permit the use of a special "EPSV ALL" command.
3456 NATs may be able to put the connection on a "fast path" through the
3457 translator, as the EPRT command will never be used and therefore,
3458 translation of the data portion of the segments will never be needed.
3460 When a client only expects to do two-way FTP transfers this may be
3462 If squid finds that it must do a three-way FTP transfer after issuing
3463 an EPSV ALL command, the FTP session will fail.
3465 If you have any doubts about this option do not use it.
3466 Squid will nicely attempt all other connection methods.
3468 Requires ftp_passive to be ON (default) for any effect.
3474 LOC: Config.Ftp.epsv
3476 FTP Protocol extensions permit the use of a special "EPSV" command.
3478 NATs may be able to put the connection on a "fast path" through the
3479 translator using EPSV, as the EPRT command will never be used
3480 and therefore, translation of the data portion of the segments
3481 will never be needed.
3483 Turning this OFF will prevent EPSV being attempted.
3484 WARNING: Doing so will convert Squid back to the old behavior with all
3485 the related problems with external NAT devices/layers.
3487 Requires ftp_passive to be ON (default) for any effect.
3490 NAME: ftp_sanitycheck
3493 LOC: Config.Ftp.sanitycheck
3495 For security and data integrity reasons Squid by default performs
3496 sanity checks of the addresses of FTP data connections ensure the
3497 data connection is to the requested server. If you need to allow
3498 FTP connections to servers using another IP address for the data
3499 connection turn this off.
3502 NAME: ftp_telnet_protocol
3505 LOC: Config.Ftp.telnet
3507 The FTP protocol is officially defined to use the telnet protocol
3508 as transport channel for the control connection. However, many
3509 implementations are broken and does not respect this aspect of
3512 If you have trouble accessing files with ASCII code 255 in the
3513 path or similar problems involving this ASCII code you can
3514 try setting this directive to off. If that helps, report to the
3515 operator of the FTP server in question that their FTP server
3516 is broken and does not follow the FTP standard.
3520 OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
3521 -----------------------------------------------------------------------------
3526 DEFAULT: @DEFAULT_DISKD@
3527 LOC: Config.Program.diskd
3529 Specify the location of the diskd executable.
3530 Note this is only useful if you have compiled in
3531 diskd as one of the store io modules.
3534 NAME: unlinkd_program
3537 DEFAULT: @DEFAULT_UNLINKD@
3538 LOC: Config.Program.unlinkd
3540 Specify the location of the executable for file deletion process.
3543 NAME: pinger_program
3545 DEFAULT: @DEFAULT_PINGER@
3546 LOC: Config.pinger.program
3549 Specify the location of the executable for the pinger process.
3555 LOC: Config.pinger.enable
3558 Control whether the pinger is active at run-time.
3559 Enables turning ICMP pinger on and off with a simple
3560 squid -k reconfigure.
3565 OPTIONS FOR URL REWRITING
3566 -----------------------------------------------------------------------------
3569 NAME: url_rewrite_program redirect_program
3571 LOC: Config.Program.redirect
3574 Specify the location of the executable for the URL rewriter.
3575 Since they can perform almost any function there isn't one included.
3577 For each requested URL rewriter will receive on line with the format
3579 URL <SP> client_ip "/" fqdn <SP> user <SP> method [<SP> kvpairs]<NL>
3581 In the future, the rewriter interface will be extended with
3582 key=value pairs ("kvpairs" shown above). Rewriter programs
3583 should be prepared to receive and possibly ignore additional
3584 whitespace-separated tokens on each input line.
3586 And the rewriter may return a rewritten URL. The other components of
3587 the request line does not need to be returned (ignored if they are).
3589 The rewriter can also indicate that a client-side redirect should
3590 be performed to the new URL. This is done by prefixing the returned
3591 URL with "301:" (moved permanently) or 302: (moved temporarily).
3593 By default, a URL rewriter is not used.
3596 NAME: url_rewrite_children redirect_children
3597 TYPE: HelperChildConfig
3598 DEFAULT: 20 startup=0 idle=1 concurrency=0
3599 LOC: Config.redirectChildren
3601 The maximum number of redirector processes to spawn. If you limit
3602 it too few Squid will have to wait for them to process a backlog of
3603 URLs, slowing it down. If you allow too many they will use RAM
3604 and other system resources noticably.
3606 The startup= and idle= options allow some measure of skew in your
3611 Sets a minimum of how many processes are to be spawned when Squid
3612 starts or reconfigures. When set to zero the first request will
3613 cause spawning of the first child process to handle it.
3615 Starting too few will cause an initial slowdown in traffic as Squid
3616 attempts to simultaneously spawn enough processes to cope.
3620 Sets a minimum of how many processes Squid is to try and keep available
3621 at all times. When traffic begins to rise above what the existing
3622 processes can handle this many more will be spawned up to the maximum
3623 configured. A minimum setting of 1 is required.
3627 The number of requests each redirector helper can handle in
3628 parallel. Defaults to 0 which indicates the redirector
3629 is a old-style single threaded redirector.
3631 When this directive is set to a value >= 1 then the protocol
3632 used to communicate with the helper is modified to include
3633 a request ID in front of the request/response. The request
3634 ID from the request must be echoed back with the response
3638 NAME: url_rewrite_host_header redirect_rewrites_host_header
3641 LOC: Config.onoff.redir_rewrites_host
3643 By default Squid rewrites any Host: header in redirected
3644 requests. If you are running an accelerator this may
3645 not be a wanted effect of a redirector.
3647 WARNING: Entries are cached on the result of the URL rewriting
3648 process, so be careful if you have domain-virtual hosts.
3651 NAME: url_rewrite_access redirector_access
3654 LOC: Config.accessList.redirector
3656 If defined, this access list specifies which requests are
3657 sent to the redirector processes. By default all requests
3660 This clause supports both fast and slow acl types.
3661 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
3664 NAME: url_rewrite_bypass redirector_bypass
3666 LOC: Config.onoff.redirector_bypass
3669 When this is 'on', a request will not go through the
3670 redirector if all redirectors are busy. If this is 'off'
3671 and the redirector queue grows too large, Squid will exit
3672 with a FATAL error and ask you to increase the number of
3673 redirectors. You should only enable this if the redirectors
3674 are not critical to your caching system. If you use
3675 redirectors for access control, and you enable this option,
3676 users may have access to pages they should not
3677 be allowed to request.
3681 OPTIONS FOR TUNING THE CACHE
3682 -----------------------------------------------------------------------------
3685 NAME: cache no_cache
3688 LOC: Config.accessList.noCache
3690 A list of ACL elements which, if matched and denied, cause the request to
3691 not be satisfied from the cache and the reply to not be cached.
3692 In other words, use this to force certain objects to never be cached.
3694 You must use the words 'allow' or 'deny' to indicate whether items
3695 matching the ACL should be allowed or denied into the cache.
3697 Default is to allow all to be cached.
3699 This clause supports both fast and slow acl types.
3700 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
3703 NAME: refresh_pattern
3704 TYPE: refreshpattern
3708 usage: refresh_pattern [-i] regex min percent max [options]
3710 By default, regular expressions are CASE-SENSITIVE. To make
3711 them case-insensitive, use the -i option.
3713 'Min' is the time (in minutes) an object without an explicit
3714 expiry time should be considered fresh. The recommended
3715 value is 0, any higher values may cause dynamic applications
3716 to be erroneously cached unless the application designer
3717 has taken the appropriate actions.
3719 'Percent' is a percentage of the objects age (time since last
3720 modification age) an object without explicit expiry time
3721 will be considered fresh.
3723 'Max' is an upper limit on how long objects without an explicit
3724 expiry time will be considered fresh.
3726 options: override-expire
3732 ignore-must-revalidate
3738 override-expire enforces min age even if the server
3739 sent an explicit expiry time (e.g., with the
3740 Expires: header or Cache-Control: max-age). Doing this
3741 VIOLATES the HTTP standard. Enabling this feature
3742 could make you liable for problems which it causes.
3744 Note: override-expire does not enforce staleness - it only extends
3745 freshness / min. If the server returns a Expires time which
3746 is longer than your max time, Squid will still consider
3747 the object fresh for that period of time.
3749 override-lastmod enforces min age even on objects
3750 that were modified recently.
3752 reload-into-ims changes client no-cache or ``reload''
3753 to If-Modified-Since requests. Doing this VIOLATES the
3754 HTTP standard. Enabling this feature could make you
3755 liable for problems which it causes.
3757 ignore-reload ignores a client no-cache or ``reload''
3758 header. Doing this VIOLATES the HTTP standard. Enabling
3759 this feature could make you liable for problems which
3762 ignore-no-cache ignores any ``Pragma: no-cache'' and
3763 ``Cache-control: no-cache'' headers received from a server.
3764 The HTTP RFC never allows the use of this (Pragma) header
3765 from a server, only a client, though plenty of servers
3768 ignore-no-store ignores any ``Cache-control: no-store''
3769 headers received from a server. Doing this VIOLATES
3770 the HTTP standard. Enabling this feature could make you
3771 liable for problems which it causes.
3773 ignore-must-revalidate ignores any ``Cache-Control: must-revalidate``
3774 headers received from a server. Doing this VIOLATES
3775 the HTTP standard. Enabling this feature could make you
3776 liable for problems which it causes.
3778 ignore-private ignores any ``Cache-control: private''
3779 headers received from a server. Doing this VIOLATES
3780 the HTTP standard. Enabling this feature could make you
3781 liable for problems which it causes.
3783 ignore-auth caches responses to requests with authorization,
3784 as if the originserver had sent ``Cache-control: public''
3785 in the response header. Doing this VIOLATES the HTTP standard.
3786 Enabling this feature could make you liable for problems which
3789 refresh-ims causes squid to contact the origin server
3790 when a client issues an If-Modified-Since request. This
3791 ensures that the client will receive an updated version
3792 if one is available.
3794 store-stale stores responses even if they don't have explicit
3795 freshness or a validator (i.e., Last-Modified or an ETag)
3796 present, or if they're already stale. By default, Squid will
3797 not cache such responses because they usually can't be
3798 reused. Note that such responses will be stale by default.
3800 Basically a cached object is:
3802 FRESH if expires < now, else STALE
3804 FRESH if lm-factor < percent, else STALE
3808 The refresh_pattern lines are checked in the order listed here.
3809 The first entry which matches is used. If none of the entries
3810 match the default will be used.
3812 Note, you must uncomment all the default lines if you want
3813 to change one. The default setting is only active if none is
3818 # Add any of your own refresh_pattern entries above these.
3819 refresh_pattern ^ftp: 1440 20% 10080
3820 refresh_pattern ^gopher: 1440 0% 1440
3821 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0
3822 refresh_pattern . 0 20% 4320
3826 NAME: quick_abort_min
3830 LOC: Config.quickAbort.min
3833 NAME: quick_abort_max
3837 LOC: Config.quickAbort.max
3840 NAME: quick_abort_pct
3844 LOC: Config.quickAbort.pct
3846 The cache by default continues downloading aborted requests
3847 which are almost completed (less than 16 KB remaining). This
3848 may be undesirable on slow (e.g. SLIP) links and/or very busy
3849 caches. Impatient users may tie up file descriptors and
3850 bandwidth by repeatedly requesting and immediately aborting
3853 When the user aborts a request, Squid will check the
3854 quick_abort values to the amount of data transfered until
3857 If the transfer has less than 'quick_abort_min' KB remaining,
3858 it will finish the retrieval.
3860 If the transfer has more than 'quick_abort_max' KB remaining,
3861 it will abort the retrieval.
3863 If more than 'quick_abort_pct' of the transfer has completed,
3864 it will finish the retrieval.
3866 If you do not want any retrieval to continue after the client
3867 has aborted, set both 'quick_abort_min' and 'quick_abort_max'
3870 If you want retrievals to always continue if they are being
3871 cached set 'quick_abort_min' to '-1 KB'.
3874 NAME: read_ahead_gap
3875 COMMENT: buffer-size
3877 LOC: Config.readAheadGap
3880 The amount of data the cache will buffer ahead of what has been
3881 sent to the client when retrieving an object from another server.
3885 IFDEF: USE_HTTP_VIOLATIONS
3888 LOC: Config.negativeTtl
3891 Set the Default Time-to-Live (TTL) for failed requests.
3892 Certain types of failures (such as "connection refused" and
3893 "404 Not Found") are able to be negatively-cached for a short time.
3894 Modern web servers should provide Expires: header, however if they
3895 do not this can provide a minimum TTL.
3896 The default is not to cache errors with unknown expiry details.
3898 Note that this is different from negative caching of DNS lookups.
3900 WARNING: Doing this VIOLATES the HTTP standard. Enabling
3901 this feature could make you liable for problems which it
3905 NAME: positive_dns_ttl
3908 LOC: Config.positiveDnsTtl
3911 Upper limit on how long Squid will cache positive DNS responses.
3912 Default is 6 hours (360 minutes). This directive must be set
3913 larger than negative_dns_ttl.
3916 NAME: negative_dns_ttl
3919 LOC: Config.negativeDnsTtl
3922 Time-to-Live (TTL) for negative caching of failed DNS lookups.
3923 This also sets the lower cache limit on positive lookups.
3924 Minimum value is 1 second, and it is not recommendable to go
3925 much below 10 seconds.
3928 NAME: range_offset_limit
3929 COMMENT: size [acl acl...]
3931 LOC: Config.rangeOffsetLimit
3934 usage: (size) [units] [[!]aclname]
3936 Sets an upper limit on how far (number of bytes) into the file
3937 a Range request may be to cause Squid to prefetch the whole file.
3938 If beyond this limit, Squid forwards the Range request as it is and
3939 the result is NOT cached.
3941 This is to stop a far ahead range request (lets say start at 17MB)
3942 from making Squid fetch the whole object up to that point before
3943 sending anything to the client.
3945 Multiple range_offset_limit lines may be specified, and they will
3946 be searched from top to bottom on each request until a match is found.
3947 The first match found will be used. If no line matches a request, the
3948 default limit of 0 bytes will be used.
3950 'size' is the limit specified as a number of units.
3952 'units' specifies whether to use bytes, KB, MB, etc.
3953 If no units are specified bytes are assumed.
3955 A size of 0 causes Squid to never fetch more than the
3956 client requested. (default)
3958 A size of 'none' causes Squid to always fetch the object from the
3959 beginning so it may cache the result. (2.0 style)
3961 'aclname' is the name of a defined ACL.
3963 NP: Using 'none' as the byte value here will override any quick_abort settings
3964 that may otherwise apply to the range request. The range request will
3965 be fully fetched from start to finish regardless of the client
3966 actions. This affects bandwidth usage.
3969 NAME: minimum_expiry_time
3972 LOC: Config.minimum_expiry_time
3975 The minimum caching time according to (Expires - Date)
3976 Headers Squid honors if the object can't be revalidated
3977 defaults to 60 seconds. In reverse proxy environments it
3978 might be desirable to honor shorter object lifetimes. It
3979 is most likely better to make your server return a
3980 meaningful Last-Modified header however. In ESI environments
3981 where page fragments often have short lifetimes, this will
3982 often be best set to 0.
3985 NAME: store_avg_object_size
3989 LOC: Config.Store.avgObjectSize
3991 Average object size, used to estimate number of objects your
3992 cache can hold. The default is 13 KB.
3995 NAME: store_objects_per_bucket
3998 LOC: Config.Store.objectsPerBucket
4000 Target number of objects per bucket in the store hash table.
4001 Lowering this value increases the total number of buckets and
4002 also the storage maintenance rate. The default is 20.
4007 -----------------------------------------------------------------------------
4010 NAME: request_header_max_size
4014 LOC: Config.maxRequestHeaderSize
4016 This specifies the maximum size for HTTP headers in a request.
4017 Request headers are usually relatively small (about 512 bytes).
4018 Placing a limit on the request header size will catch certain
4019 bugs (for example with persistent connections) and possibly
4020 buffer-overflow or denial-of-service attacks.
4023 NAME: reply_header_max_size
4027 LOC: Config.maxReplyHeaderSize
4029 This specifies the maximum size for HTTP headers in a reply.
4030 Reply headers are usually relatively small (about 512 bytes).
4031 Placing a limit on the reply header size will catch certain
4032 bugs (for example with persistent connections) and possibly
4033 buffer-overflow or denial-of-service attacks.
4036 NAME: request_body_max_size
4040 LOC: Config.maxRequestBodySize
4042 This specifies the maximum size for an HTTP request body.
4043 In other words, the maximum size of a PUT/POST request.
4044 A user who attempts to send a request with a body larger
4045 than this limit receives an "Invalid Request" error message.
4046 If you set this parameter to a zero (the default), there will
4047 be no limit imposed.
4050 NAME: chunked_request_body_max_size
4054 LOC: Config.maxChunkedRequestBodySize
4056 A broken or confused HTTP/1.1 client may send a chunked HTTP
4057 request to Squid. Squid does not have full support for that
4058 feature yet. To cope with such requests, Squid buffers the
4059 entire request and then dechunks request body to create a
4060 plain HTTP/1.0 request with a known content length. The plain
4061 request is then used by the rest of Squid code as usual.
4063 The option value specifies the maximum size of the buffer used
4064 to hold the request before the conversion. If the chunked
4065 request size exceeds the specified limit, the conversion
4066 fails, and the client receives an "unsupported request" error,
4067 as if dechunking was disabled.
4069 Dechunking is enabled by default. To disable conversion of
4070 chunked requests, set the maximum to zero.
4072 Request dechunking feature and this option in particular are a
4073 temporary hack. When chunking requests and responses are fully
4074 supported, there will be no need to buffer a chunked request.
4078 IFDEF: USE_HTTP_VIOLATIONS
4081 LOC: Config.accessList.brokenPosts
4083 A list of ACL elements which, if matched, causes Squid to send
4084 an extra CRLF pair after the body of a PUT/POST request.
4086 Some HTTP servers has broken implementations of PUT/POST,
4087 and rely on an extra CRLF pair sent by some WWW clients.
4089 Quote from RFC2616 section 4.1 on this matter:
4091 Note: certain buggy HTTP/1.0 client implementations generate an
4092 extra CRLF's after a POST request. To restate what is explicitly
4093 forbidden by the BNF, an HTTP/1.1 client must not preface or follow
4094 a request with an extra CRLF.
4096 This clause only supports fast acl types.
4097 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4100 acl buggy_server url_regex ^http://....
4101 broken_posts allow buggy_server
4104 NAME: icap_uses_indirect_client
4107 IFDEF: FOLLOW_X_FORWARDED_FOR&&ICAP_CLIENT
4109 LOC: Adaptation::Icap::TheConfig.icap_uses_indirect_client
4111 Controls whether the indirect client address
4112 (see follow_x_forwarded_for) instead of the
4113 direct client address is passed to an ICAP
4114 server as "X-Client-IP".
4118 IFDEF: USE_HTTP_VIOLATIONS
4122 LOC: Config.onoff.via
4124 If set (default), Squid will include a Via header in requests and
4125 replies as required by RFC2616.
4131 LOC: Config.onoff.ie_refresh
4134 Microsoft Internet Explorer up until version 5.5 Service
4135 Pack 1 has an issue with transparent proxies, wherein it
4136 is impossible to force a refresh. Turning this on provides
4137 a partial fix to the problem, by causing all IMS-REFRESH
4138 requests from older IE versions to check the origin server
4139 for fresh content. This reduces hit ratio by some amount
4140 (~10% in my experience), but allows users to actually get
4141 fresh content when they want it. Note because Squid
4142 cannot tell if the user is using 5.5 or 5.5SP1, the behavior
4143 of 5.5 is unchanged from old versions of Squid (i.e. a
4144 forced refresh is impossible). Newer versions of IE will,
4145 hopefully, continue to have the new behavior and will be
4146 handled based on that assumption. This option defaults to
4147 the old Squid behavior, which is better for hit ratios but
4148 worse for clients using IE, if they need to be able to
4149 force fresh content.
4152 NAME: vary_ignore_expire
4155 LOC: Config.onoff.vary_ignore_expire
4158 Many HTTP servers supporting Vary gives such objects
4159 immediate expiry time with no cache-control header
4160 when requested by a HTTP/1.0 client. This option
4161 enables Squid to ignore such expiry times until
4162 HTTP/1.1 is fully implemented.
4164 WARNING: If turned on this may eventually cause some
4165 varying objects not intended for caching to get cached.
4168 NAME: request_entities
4170 LOC: Config.onoff.request_entities
4173 Squid defaults to deny GET and HEAD requests with request entities,
4174 as the meaning of such requests are undefined in the HTTP standard
4175 even if not explicitly forbidden.
4177 Set this directive to on if you have clients which insists
4178 on sending request entities in GET or HEAD requests. But be warned
4179 that there is server software (both proxies and web servers) which
4180 can fail to properly process this kind of request which may make you
4181 vulnerable to cache pollution attacks if enabled.
4184 NAME: request_header_access
4185 IFDEF: USE_HTTP_VIOLATIONS
4186 TYPE: http_header_access[]
4187 LOC: Config.request_header_access
4190 Usage: request_header_access header_name allow|deny [!]aclname ...
4192 WARNING: Doing this VIOLATES the HTTP standard. Enabling
4193 this feature could make you liable for problems which it
4196 This option replaces the old 'anonymize_headers' and the
4197 older 'http_anonymizer' option with something that is much
4198 more configurable. This new method creates a list of ACLs
4199 for each header, allowing you very fine-tuned header
4202 This option only applies to request headers, i.e., from the
4203 client to the server.
4205 You can only specify known headers for the header name.
4206 Other headers are reclassified as 'Other'. You can also
4207 refer to all the headers with 'All'.
4209 For example, to achieve the same behavior as the old
4210 'http_anonymizer standard' option, you should use:
4212 request_header_access From deny all
4213 request_header_access Referer deny all
4214 request_header_access Server deny all
4215 request_header_access User-Agent deny all
4216 request_header_access WWW-Authenticate deny all
4217 request_header_access Link deny all
4219 Or, to reproduce the old 'http_anonymizer paranoid' feature
4222 request_header_access Allow allow all
4223 request_header_access Authorization allow all
4224 request_header_access WWW-Authenticate allow all
4225 request_header_access Proxy-Authorization allow all
4226 request_header_access Proxy-Authenticate allow all
4227 request_header_access Cache-Control allow all
4228 request_header_access Content-Encoding allow all
4229 request_header_access Content-Length allow all
4230 request_header_access Content-Type allow all
4231 request_header_access Date allow all
4232 request_header_access Expires allow all
4233 request_header_access Host allow all
4234 request_header_access If-Modified-Since allow all
4235 request_header_access Last-Modified allow all
4236 request_header_access Location allow all
4237 request_header_access Pragma allow all
4238 request_header_access Accept allow all
4239 request_header_access Accept-Charset allow all
4240 request_header_access Accept-Encoding allow all
4241 request_header_access Accept-Language allow all
4242 request_header_access Content-Language allow all
4243 request_header_access Mime-Version allow all
4244 request_header_access Retry-After allow all
4245 request_header_access Title allow all
4246 request_header_access Connection allow all
4247 request_header_access All deny all
4249 although many of those are HTTP reply headers, and so should be
4250 controlled with the reply_header_access directive.
4252 By default, all headers are allowed (no anonymizing is
4256 NAME: reply_header_access
4257 IFDEF: USE_HTTP_VIOLATIONS
4258 TYPE: http_header_access[]
4259 LOC: Config.reply_header_access
4262 Usage: reply_header_access header_name allow|deny [!]aclname ...
4264 WARNING: Doing this VIOLATES the HTTP standard. Enabling
4265 this feature could make you liable for problems which it
4268 This option only applies to reply headers, i.e., from the
4269 server to the client.
4271 This is the same as request_header_access, but in the other
4274 This option replaces the old 'anonymize_headers' and the
4275 older 'http_anonymizer' option with something that is much
4276 more configurable. This new method creates a list of ACLs
4277 for each header, allowing you very fine-tuned header
4280 You can only specify known headers for the header name.
4281 Other headers are reclassified as 'Other'. You can also
4282 refer to all the headers with 'All'.
4284 For example, to achieve the same behavior as the old
4285 'http_anonymizer standard' option, you should use:
4287 reply_header_access From deny all
4288 reply_header_access Referer deny all
4289 reply_header_access Server deny all
4290 reply_header_access User-Agent deny all
4291 reply_header_access WWW-Authenticate deny all
4292 reply_header_access Link deny all
4294 Or, to reproduce the old 'http_anonymizer paranoid' feature
4297 reply_header_access Allow allow all
4298 reply_header_access Authorization allow all
4299 reply_header_access WWW-Authenticate allow all
4300 reply_header_access Proxy-Authorization allow all
4301 reply_header_access Proxy-Authenticate allow all
4302 reply_header_access Cache-Control allow all
4303 reply_header_access Content-Encoding allow all
4304 reply_header_access Content-Length allow all
4305 reply_header_access Content-Type allow all
4306 reply_header_access Date allow all
4307 reply_header_access Expires allow all
4308 reply_header_access Host allow all
4309 reply_header_access If-Modified-Since allow all
4310 reply_header_access Last-Modified allow all
4311 reply_header_access Location allow all
4312 reply_header_access Pragma allow all
4313 reply_header_access Accept allow all
4314 reply_header_access Accept-Charset allow all
4315 reply_header_access Accept-Encoding allow all
4316 reply_header_access Accept-Language allow all
4317 reply_header_access Content-Language allow all
4318 reply_header_access Mime-Version allow all
4319 reply_header_access Retry-After allow all
4320 reply_header_access Title allow all
4321 reply_header_access Connection allow all
4322 reply_header_access All deny all
4324 although the HTTP request headers won't be usefully controlled
4325 by this directive -- see request_header_access for details.
4327 By default, all headers are allowed (no anonymizing is
4331 NAME: header_replace
4332 IFDEF: USE_HTTP_VIOLATIONS
4333 TYPE: http_header_replace[]
4334 LOC: Config.request_header_access
4337 Usage: header_replace header_name message
4338 Example: header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
4340 This option allows you to change the contents of headers
4341 denied with header_access above, by replacing them with
4342 some fixed string. This replaces the old fake_user_agent
4345 This only applies to request headers, not reply headers.
4347 By default, headers are removed if denied.
4350 NAME: relaxed_header_parser
4351 COMMENT: on|off|warn
4353 LOC: Config.onoff.relaxed_header_parser
4356 In the default "on" setting Squid accepts certain forms
4357 of non-compliant HTTP messages where it is unambiguous
4358 what the sending application intended even if the message
4359 is not correctly formatted. The messages is then normalized
4360 to the correct form when forwarded by Squid.
4362 If set to "warn" then a warning will be emitted in cache.log
4363 each time such HTTP error is encountered.
4365 If set to "off" then such HTTP errors will cause the request
4366 or response to be rejected.
4371 -----------------------------------------------------------------------------
4374 NAME: forward_timeout
4377 LOC: Config.Timeout.forward
4380 This parameter specifies how long Squid should at most attempt in
4381 finding a forwarding path for the request before giving up.
4384 NAME: connect_timeout
4387 LOC: Config.Timeout.connect
4390 This parameter specifies how long to wait for the TCP connect to
4391 the requested server or peer to complete before Squid should
4392 attempt to find another path where to forward the request.
4395 NAME: peer_connect_timeout
4398 LOC: Config.Timeout.peer_connect
4401 This parameter specifies how long to wait for a pending TCP
4402 connection to a peer cache. The default is 30 seconds. You
4403 may also set different timeout values for individual neighbors
4404 with the 'connect-timeout' option on a 'cache_peer' line.
4410 LOC: Config.Timeout.read
4413 The read_timeout is applied on server-side connections. After
4414 each successful read(), the timeout will be extended by this
4415 amount. If no data is read again after this amount of time,
4416 the request is aborted and logged with ERR_READ_TIMEOUT. The
4417 default is 15 minutes.
4423 LOC: Config.Timeout.write
4426 This timeout is tracked for all connections that have data
4427 available for writing and are waiting for the socket to become
4428 ready. After each successful write, the timeout is extended by
4429 the configured amount. If Squid has data to write but the
4430 connection is not ready for the configured duration, the
4431 transaction associated with the connection is terminated. The
4432 default is 15 minutes.
4435 NAME: request_timeout
4437 LOC: Config.Timeout.request
4440 How long to wait for an HTTP request after initial
4441 connection establishment.
4444 NAME: persistent_request_timeout
4446 LOC: Config.Timeout.persistent_request
4449 How long to wait for the next HTTP request on a persistent
4450 connection after the previous request completes.
4453 NAME: client_lifetime
4456 LOC: Config.Timeout.lifetime
4459 The maximum amount of time a client (browser) is allowed to
4460 remain connected to the cache process. This protects the Cache
4461 from having a lot of sockets (and hence file descriptors) tied up
4462 in a CLOSE_WAIT state from remote clients that go away without
4463 properly shutting down (either because of a network failure or
4464 because of a poor client implementation). The default is one
4467 NOTE: The default value is intended to be much larger than any
4468 client would ever need to be connected to your cache. You
4469 should probably change client_lifetime only as a last resort.
4470 If you seem to have many client connections tying up
4471 filedescriptors, we recommend first tuning the read_timeout,
4472 request_timeout, persistent_request_timeout and quick_abort values.
4475 NAME: half_closed_clients
4477 LOC: Config.onoff.half_closed_clients
4480 Some clients may shutdown the sending side of their TCP
4481 connections, while leaving their receiving sides open. Sometimes,
4482 Squid can not tell the difference between a half-closed and a
4483 fully-closed TCP connection.
4485 By default, Squid will immediately close client connections when
4486 read(2) returns "no more data to read."
4488 Change this option to 'on' and Squid will keep open connections
4489 until a read(2) or write(2) on the socket returns an error.
4490 This may show some benefits for reverse proxies. But if not
4491 it is recommended to leave OFF.
4496 LOC: Config.Timeout.pconn
4499 Timeout for idle persistent connections to servers and other
4506 LOC: Ident::TheConfig.timeout
4509 Maximum time to wait for IDENT lookups to complete.
4511 If this is too high, and you enabled IDENT lookups from untrusted
4512 users, you might be susceptible to denial-of-service by having
4513 many ident requests going at once.
4516 NAME: shutdown_lifetime
4519 LOC: Config.shutdownLifetime
4522 When SIGTERM or SIGHUP is received, the cache is put into
4523 "shutdown pending" mode until all active sockets are closed.
4524 This value is the lifetime to set for all open descriptors
4525 during shutdown mode. Any active clients after this many
4526 seconds will receive a 'timeout' message.
4530 ADMINISTRATIVE PARAMETERS
4531 -----------------------------------------------------------------------------
4537 LOC: Config.adminEmail
4539 Email-address of local cache manager who will receive
4540 mail if the cache dies. The default is "webmaster."
4546 LOC: Config.EmailFrom
4548 From: email-address for mail sent when the cache dies.
4549 The default is to use 'appname@unique_hostname'.
4550 Default appname value is "squid", can be changed into
4551 src/globals.h before building squid.
4557 LOC: Config.EmailProgram
4559 Email program used to send mail if the cache dies.
4560 The default is "mail". The specified program must comply
4561 with the standard Unix mail syntax:
4562 mail-program recipient < mailfile
4564 Optional command line options can be specified.
4567 NAME: cache_effective_user
4569 DEFAULT: @DEFAULT_CACHE_EFFECTIVE_USER@
4570 LOC: Config.effectiveUser
4572 If you start Squid as root, it will change its effective/real
4573 UID/GID to the user specified below. The default is to change
4574 to UID of @DEFAULT_CACHE_EFFECTIVE_USER@.
4575 see also; cache_effective_group
4578 NAME: cache_effective_group
4581 LOC: Config.effectiveGroup
4583 Squid sets the GID to the effective user's default group ID
4584 (taken from the password file) and supplementary group list
4585 from the groups membership.
4587 If you want Squid to run with a specific GID regardless of
4588 the group memberships of the effective user then set this
4589 to the group (or GID) you want Squid to run as. When set
4590 all other group privileges of the effective user are ignored
4591 and only this GID is effective. If Squid is not started as
4592 root the user starting Squid MUST be member of the specified
4595 This option is not recommended by the Squid Team.
4596 Our preference is for administrators to configure a secure
4597 user account for squid with UID/GID matching system policies.
4600 NAME: httpd_suppress_version_string
4604 LOC: Config.onoff.httpd_suppress_version_string
4606 Suppress Squid version string info in HTTP headers and HTML error pages.
4609 NAME: visible_hostname
4611 LOC: Config.visibleHostname
4614 If you want to present a special hostname in error messages, etc,
4615 define this. Otherwise, the return value of gethostname()
4616 will be used. If you have multiple caches in a cluster and
4617 get errors about IP-forwarding you must set them to have individual
4618 names with this setting.
4621 NAME: unique_hostname
4623 LOC: Config.uniqueHostname
4626 If you want to have multiple machines with the same
4627 'visible_hostname' you must give each machine a different
4628 'unique_hostname' so forwarding loops can be detected.
4631 NAME: hostname_aliases
4633 LOC: Config.hostnameAliases
4636 A list of other DNS names your cache has.
4644 Minimum umask which should be enforced while the proxy
4645 is running, in addition to the umask set at startup.
4647 For a traditional octal representation of umasks, start
4652 OPTIONS FOR THE CACHE REGISTRATION SERVICE
4653 -----------------------------------------------------------------------------
4655 This section contains parameters for the (optional) cache
4656 announcement service. This service is provided to help
4657 cache administrators locate one another in order to join or
4658 create cache hierarchies.
4660 An 'announcement' message is sent (via UDP) to the registration
4661 service by Squid. By default, the announcement message is NOT
4662 SENT unless you enable it with 'announce_period' below.
4664 The announcement message includes your hostname, plus the
4665 following information from this configuration file:
4671 All current information is processed regularly and made
4672 available on the Web at http://www.ircache.net/Cache/Tracker/.
4675 NAME: announce_period
4677 LOC: Config.Announce.period
4680 This is how frequently to send cache announcements. The
4681 default is `0' which disables sending the announcement
4684 To enable announcing your cache, just set an announce period.
4687 announce_period 1 day
4692 DEFAULT: tracker.ircache.net
4693 LOC: Config.Announce.host
4699 LOC: Config.Announce.file
4705 LOC: Config.Announce.port
4707 announce_host and announce_port set the hostname and port
4708 number where the registration message will be sent.
4710 Hostname will default to 'tracker.ircache.net' and port will
4711 default default to 3131. If the 'filename' argument is given,
4712 the contents of that file will be included in the announce
4717 HTTPD-ACCELERATOR OPTIONS
4718 -----------------------------------------------------------------------------
4721 NAME: httpd_accel_surrogate_id
4724 LOC: Config.Accel.surrogate_id
4726 Surrogates (http://www.esi.org/architecture_spec_1.0.html)
4727 need an identification token to allow control targeting. Because
4728 a farm of surrogates may all perform the same tasks, they may share
4729 an identification token.
4731 The default ID is the visible_hostname
4734 NAME: http_accel_surrogate_remote
4738 LOC: Config.onoff.surrogate_is_remote
4740 Remote surrogates (such as those in a CDN) honour Surrogate-Control: no-store-remote.
4741 Set this to on to have squid behave as a remote surrogate.
4745 IFDEF: USE_SQUID_ESI
4746 COMMENT: libxml2|expat|custom
4748 LOC: ESIParser::Type
4751 ESI markup is not strictly XML compatible. The custom ESI parser
4752 will give higher performance, but cannot handle non ASCII character
4757 DELAY POOL PARAMETERS
4758 -----------------------------------------------------------------------------
4762 TYPE: delay_pool_count
4764 IFDEF: USE_DELAY_POOLS
4767 This represents the number of delay pools to be used. For example,
4768 if you have one class 2 delay pool and one class 3 delays pool, you
4769 have a total of 2 delay pools.
4773 TYPE: delay_pool_class
4775 IFDEF: USE_DELAY_POOLS
4778 This defines the class of each delay pool. There must be exactly one
4779 delay_class line for each delay pool. For example, to define two
4780 delay pools, one of class 2 and one of class 3, the settings above
4784 delay_pools 4 # 4 delay pools
4785 delay_class 1 2 # pool 1 is a class 2 pool
4786 delay_class 2 3 # pool 2 is a class 3 pool
4787 delay_class 3 4 # pool 3 is a class 4 pool
4788 delay_class 4 5 # pool 4 is a class 5 pool
4790 The delay pool classes are:
4792 class 1 Everything is limited by a single aggregate
4795 class 2 Everything is limited by a single aggregate
4796 bucket as well as an "individual" bucket chosen
4797 from bits 25 through 32 of the IPv4 address.
4799 class 3 Everything is limited by a single aggregate
4800 bucket as well as a "network" bucket chosen
4801 from bits 17 through 24 of the IP address and a
4802 "individual" bucket chosen from bits 17 through
4803 32 of the IPv4 address.
4805 class 4 Everything in a class 3 delay pool, with an
4806 additional limit on a per user basis. This
4807 only takes effect if the username is established
4808 in advance - by forcing authentication in your
4811 class 5 Requests are grouped according their tag (see
4812 external_acl's tag= reply).
4814 NOTE: If an IP address is a.b.c.d
4815 -> bits 25 through 32 are "d"
4816 -> bits 17 through 24 are "c"
4817 -> bits 17 through 32 are "c * 256 + d"
4819 NOTE-2: Due to the use of bitmasks in class 2,3,4 pools they only apply to
4820 IPv4 traffic. Class 1 and 5 pools may be used with IPv6 traffic.
4824 TYPE: delay_pool_access
4826 IFDEF: USE_DELAY_POOLS
4829 This is used to determine which delay pool a request falls into.
4831 delay_access is sorted per pool and the matching starts with pool 1,
4832 then pool 2, ..., and finally pool N. The first delay pool where the
4833 request is allowed is selected for the request. If it does not allow
4834 the request to any pool then the request is not delayed (default).
4836 For example, if you want some_big_clients in delay
4837 pool 1 and lotsa_little_clients in delay pool 2:
4840 delay_access 1 allow some_big_clients
4841 delay_access 1 deny all
4842 delay_access 2 allow lotsa_little_clients
4843 delay_access 2 deny all
4844 delay_access 3 allow authenticated_clients
4847 NAME: delay_parameters
4848 TYPE: delay_pool_rates
4850 IFDEF: USE_DELAY_POOLS
4853 This defines the parameters for a delay pool. Each delay pool has
4854 a number of "buckets" associated with it, as explained in the
4855 description of delay_class. For a class 1 delay pool, the syntax is:
4857 delay_parameters pool aggregate
4859 For a class 2 delay pool:
4861 delay_parameters pool aggregate individual
4863 For a class 3 delay pool:
4865 delay_parameters pool aggregate network individual
4867 For a class 4 delay pool:
4869 delay_parameters pool aggregate network individual user
4871 For a class 5 delay pool:
4873 delay_parameters pool tag
4875 The variables here are:
4877 pool a pool number - ie, a number between 1 and the
4878 number specified in delay_pools as used in
4881 aggregate the "delay parameters" for the aggregate bucket
4884 individual the "delay parameters" for the individual
4885 buckets (class 2, 3).
4887 network the "delay parameters" for the network buckets
4890 user the delay parameters for the user buckets
4893 tag the delay parameters for the tag buckets
4896 A pair of delay parameters is written restore/maximum, where restore is
4897 the number of bytes (not bits - modem and network speeds are usually
4898 quoted in bits) per second placed into the bucket, and maximum is the
4899 maximum number of bytes which can be in the bucket at any time.
4901 For example, if delay pool number 1 is a class 2 delay pool as in the
4902 above example, and is being used to strictly limit each host to 64kbps
4903 (plus overheads), with no overall limit, the line is:
4905 delay_parameters 1 -1/-1 8000/8000
4907 Note that the figure -1 is used to represent "unlimited".
4909 And, if delay pool number 2 is a class 3 delay pool as in the above
4910 example, and you want to limit it to a total of 256kbps (strict limit)
4911 with each 8-bit network permitted 64kbps (strict limit) and each
4912 individual host permitted 4800bps with a bucket maximum size of 64kb
4913 to permit a decent web page to be downloaded at a decent speed
4914 (if the network is not being limited due to overuse) but slow down
4915 large downloads more significantly:
4917 delay_parameters 2 32000/32000 8000/8000 600/8000
4919 There must be one delay_parameters line for each delay pool.
4921 Finally, for a class 4 delay pool as in the example - each user will
4922 be limited to 128Kb no matter how many workstations they are logged into.:
4924 delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000
4927 NAME: delay_initial_bucket_level
4928 COMMENT: (percent, 0-100)
4931 IFDEF: USE_DELAY_POOLS
4932 LOC: Config.Delay.initial
4934 The initial bucket percentage is used to determine how much is put
4935 in each bucket when squid starts, is reconfigured, or first notices
4936 a host accessing it (in class 2 and class 3, individual hosts and
4937 networks only have buckets associated with them once they have been
4942 CLIENT DELAY POOL PARAMETERS
4943 -----------------------------------------------------------------------------
4946 NAME: client_delay_pools
4947 TYPE: client_delay_pool_count
4949 IFDEF: USE_DELAY_POOLS
4950 LOC: Config.ClientDelay
4952 This option specifies the number of client delay pools used. It must
4953 preceed other client_delay_* options.
4956 client_delay_pools 2
4959 NAME: client_delay_initial_bucket_level
4960 COMMENT: (percent, 0-no_limit)
4963 IFDEF: USE_DELAY_POOLS
4964 LOC: Config.ClientDelay.initial
4966 This option determines the initial bucket size as a percentage of
4967 max_bucket_size from client_delay_parameters. Buckets are created
4968 at the time of the "first" connection from the matching IP. Idle
4969 buckets are periodically deleted up.
4971 You can specify more than 100 percent but note that such "oversized"
4972 buckets are not refilled until their size goes down to max_bucket_size
4973 from client_delay_parameters.
4976 client_delay_initial_bucket_level 50
4979 NAME: client_delay_parameters
4980 TYPE: client_delay_pool_rates
4982 IFDEF: USE_DELAY_POOLS
4983 LOC: Config.ClientDelay
4986 This option configures client-side bandwidth limits using the
4989 client_delay_parameters pool speed_limit max_bucket_size
4991 pool is an integer ID used for client_delay_access matching.
4993 speed_limit is bytes added to the bucket per second.
4995 max_bucket_size is the maximum size of a bucket, enforced after any
4996 speed_limit additions.
4998 Please see the delay_parameters option for more information and
5002 client_delay_parameters 1 1024 2048
5003 client_delay_parameters 2 51200 16384
5006 NAME: client_delay_access
5007 TYPE: client_delay_pool_access
5009 IFDEF: USE_DELAY_POOLS
5010 LOC: Config.ClientDelay
5013 This option determines the client-side delay pool for the
5016 client_delay_access pool_ID allow|deny acl_name
5018 All client_delay_access options are checked in their pool ID
5019 order, starting with pool 1. The first checked pool with allowed
5020 request is selected for the request. If no ACL matches or there
5021 are no client_delay_access options, the request bandwidth is not
5024 The ACL-selected pool is then used to find the
5025 client_delay_parameters for the request. Client-side pools are
5026 not used to aggregate clients. Clients are always aggregated
5027 based on their source IP addresses (one bucket per source IP).
5029 Please see delay_access for more examples.
5032 client_delay_access 1 allow low_rate_network
5033 client_delay_access 2 allow vips_network
5037 WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS
5038 -----------------------------------------------------------------------------
5043 LOC: Config.Wccp.router
5047 Use this option to define your WCCP ``home'' router for
5050 wccp_router supports a single WCCP(v1) router
5052 wccp2_router supports multiple WCCPv2 routers
5054 only one of the two may be used at the same time and defines
5055 which version of WCCP to use.
5059 TYPE: IpAddress_list
5060 LOC: Config.Wccp2.router
5064 Use this option to define your WCCP ``home'' router for
5067 wccp_router supports a single WCCP(v1) router
5069 wccp2_router supports multiple WCCPv2 routers
5071 only one of the two may be used at the same time and defines
5072 which version of WCCP to use.
5077 LOC: Config.Wccp.version
5081 This directive is only relevant if you need to set up WCCP(v1)
5082 to some very old and end-of-life Cisco routers. In all other
5083 setups it must be left unset or at the default setting.
5084 It defines an internal version in the WCCP(v1) protocol,
5085 with version 4 being the officially documented protocol.
5087 According to some users, Cisco IOS 11.2 and earlier only
5088 support WCCP version 3. If you're using that or an earlier
5089 version of IOS, you may need to change this value to 3, otherwise
5090 do not specify this parameter.
5093 NAME: wccp2_rebuild_wait
5095 LOC: Config.Wccp2.rebuildwait
5099 If this is enabled Squid will wait for the cache dir rebuild to finish
5100 before sending the first wccp2 HereIAm packet
5103 NAME: wccp2_forwarding_method
5105 LOC: Config.Wccp2.forwarding_method
5109 WCCP2 allows the setting of forwarding methods between the
5110 router/switch and the cache. Valid values are as follows:
5112 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
5113 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
5115 Currently (as of IOS 12.4) cisco routers only support GRE.
5116 Cisco switches only support the L2 redirect assignment method.
5119 NAME: wccp2_return_method
5121 LOC: Config.Wccp2.return_method
5125 WCCP2 allows the setting of return methods between the
5126 router/switch and the cache for packets that the cache
5127 decides not to handle. Valid values are as follows:
5129 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
5130 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
5132 Currently (as of IOS 12.4) cisco routers only support GRE.
5133 Cisco switches only support the L2 redirect assignment.
5135 If the "ip wccp redirect exclude in" command has been
5136 enabled on the cache interface, then it is still safe for
5137 the proxy server to use a l2 redirect method even if this
5138 option is set to GRE.
5141 NAME: wccp2_assignment_method
5143 LOC: Config.Wccp2.assignment_method
5147 WCCP2 allows the setting of methods to assign the WCCP hash
5148 Valid values are as follows:
5150 hash - Hash assignment
5151 mask - Mask assignment
5153 As a general rule, cisco routers support the hash assignment method
5154 and cisco switches support the mask assignment method.
5159 LOC: Config.Wccp2.info
5160 DEFAULT_IF_NONE: standard 0
5163 WCCP2 allows for multiple traffic services. There are two
5164 types: "standard" and "dynamic". The standard type defines
5165 one service id - http (id 0). The dynamic service ids can be from
5166 51 to 255 inclusive. In order to use a dynamic service id
5167 one must define the type of traffic to be redirected; this is done
5168 using the wccp2_service_info option.
5170 The "standard" type does not require a wccp2_service_info option,
5171 just specifying the service id will suffice.
5173 MD5 service authentication can be enabled by adding
5174 "password=<password>" to the end of this service declaration.
5178 wccp2_service standard 0 # for the 'web-cache' standard service
5179 wccp2_service dynamic 80 # a dynamic service type which will be
5180 # fleshed out with subsequent options.
5181 wccp2_service standard 0 password=foo
5184 NAME: wccp2_service_info
5185 TYPE: wccp2_service_info
5186 LOC: Config.Wccp2.info
5190 Dynamic WCCPv2 services require further information to define the
5191 traffic you wish to have diverted.
5195 wccp2_service_info <id> protocol=<protocol> flags=<flag>,<flag>..
5196 priority=<priority> ports=<port>,<port>..
5198 The relevant WCCPv2 flags:
5199 + src_ip_hash, dst_ip_hash
5200 + source_port_hash, dst_port_hash
5201 + src_ip_alt_hash, dst_ip_alt_hash
5202 + src_port_alt_hash, dst_port_alt_hash
5205 The port list can be one to eight entries.
5209 wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source
5210 priority=240 ports=80
5212 Note: the service id must have been defined by a previous
5213 'wccp2_service dynamic <id>' entry.
5218 LOC: Config.Wccp2.weight
5222 Each cache server gets assigned a set of the destination
5223 hash proportional to their weight.
5228 LOC: Config.Wccp.address
5235 LOC: Config.Wccp2.address
5239 Use this option if you require WCCP to use a specific
5242 The default behavior is to not bind to any specific address.
5246 PERSISTENT CONNECTION HANDLING
5247 -----------------------------------------------------------------------------
5249 Also see "pconn_timeout" in the TIMEOUTS section
5252 NAME: client_persistent_connections
5254 LOC: Config.onoff.client_pconns
5258 NAME: server_persistent_connections
5260 LOC: Config.onoff.server_pconns
5263 Persistent connection support for clients and servers. By
5264 default, Squid uses persistent connections (when allowed)
5265 with its clients and servers. You can use these options to
5266 disable persistent connections with clients and/or servers.
5269 NAME: persistent_connection_after_error
5271 LOC: Config.onoff.error_pconns
5274 With this directive the use of persistent connections after
5275 HTTP errors can be disabled. Useful if you have clients
5276 who fail to handle errors on persistent connections proper.
5279 NAME: detect_broken_pconn
5281 LOC: Config.onoff.detect_broken_server_pconns
5284 Some servers have been found to incorrectly signal the use
5285 of HTTP/1.0 persistent connections even on replies not
5286 compatible, causing significant delays. This server problem
5287 has mostly been seen on redirects.
5289 By enabling this directive Squid attempts to detect such
5290 broken replies and automatically assume the reply is finished
5291 after 10 seconds timeout.
5295 CACHE DIGEST OPTIONS
5296 -----------------------------------------------------------------------------
5299 NAME: digest_generation
5300 IFDEF: USE_CACHE_DIGESTS
5302 LOC: Config.onoff.digest_generation
5305 This controls whether the server will generate a Cache Digest
5306 of its contents. By default, Cache Digest generation is
5307 enabled if Squid is compiled with --enable-cache-digests defined.
5310 NAME: digest_bits_per_entry
5311 IFDEF: USE_CACHE_DIGESTS
5313 LOC: Config.digest.bits_per_entry
5316 This is the number of bits of the server's Cache Digest which
5317 will be associated with the Digest entry for a given HTTP
5318 Method and URL (public key) combination. The default is 5.
5321 NAME: digest_rebuild_period
5322 IFDEF: USE_CACHE_DIGESTS
5325 LOC: Config.digest.rebuild_period
5328 This is the wait time between Cache Digest rebuilds.
5331 NAME: digest_rewrite_period
5333 IFDEF: USE_CACHE_DIGESTS
5335 LOC: Config.digest.rewrite_period
5338 This is the wait time between Cache Digest writes to
5342 NAME: digest_swapout_chunk_size
5345 IFDEF: USE_CACHE_DIGESTS
5346 LOC: Config.digest.swapout_chunk_size
5349 This is the number of bytes of the Cache Digest to write to
5350 disk at a time. It defaults to 4096 bytes (4KB), the Squid
5354 NAME: digest_rebuild_chunk_percentage
5355 COMMENT: (percent, 0-100)
5356 IFDEF: USE_CACHE_DIGESTS
5358 LOC: Config.digest.rebuild_chunk_percentage
5361 This is the percentage of the Cache Digest to be scanned at a
5362 time. By default it is set to 10% of the Cache Digest.
5367 -----------------------------------------------------------------------------
5372 LOC: Config.Port.snmp
5376 The port number where Squid listens for SNMP requests. To enable
5377 SNMP support set this to a suitable port number. Port number
5378 3401 is often used for the Squid SNMP agent. By default it's
5379 set to "0" (disabled)
5387 LOC: Config.accessList.snmp
5388 DEFAULT_IF_NONE: deny all
5391 Allowing or denying access to the SNMP port.
5393 All access to the agent is denied by default.
5396 snmp_access allow|deny [!]aclname ...
5398 This clause only supports fast acl types.
5399 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5401 snmp_access allow snmppublic localhost
5402 snmp_access deny all
5405 NAME: snmp_incoming_address
5407 LOC: Config.Addrs.snmp_incoming
5412 NAME: snmp_outgoing_address
5414 LOC: Config.Addrs.snmp_outgoing
5418 Just like 'udp_incoming_address', but for the SNMP port.
5420 snmp_incoming_address is used for the SNMP socket receiving
5421 messages from SNMP agents.
5422 snmp_outgoing_address is used for SNMP packets returned to SNMP
5425 The default snmp_incoming_address is to listen on all
5426 available network interfaces.
5428 If snmp_outgoing_address is not set it will use the same socket
5429 as snmp_incoming_address. Only change this if you want to have
5430 SNMP replies sent using another address than where this Squid
5431 listens for SNMP queries.
5433 NOTE, snmp_incoming_address and snmp_outgoing_address can not have
5434 the same value since they both use port 3401.
5439 -----------------------------------------------------------------------------
5442 NAME: icp_port udp_port
5445 LOC: Config.Port.icp
5447 The port number where Squid sends and receives ICP queries to
5448 and from neighbor caches. The standard UDP port for ICP is 3130.
5449 Default is disabled (0).
5452 icp_port @DEFAULT_ICP_PORT@
5459 LOC: Config.Port.htcp
5461 The port number where Squid sends and receives HTCP queries to
5462 and from neighbor caches. To turn it on you want to set it to
5463 4827. By default it is set to "0" (disabled).
5469 NAME: log_icp_queries
5473 LOC: Config.onoff.log_udp
5475 If set, ICP queries are logged to access.log. You may wish
5476 do disable this if your ICP load is VERY high to speed things
5477 up or to simplify log analysis.
5480 NAME: udp_incoming_address
5482 LOC:Config.Addrs.udp_incoming
5485 udp_incoming_address is used for UDP packets received from other
5488 The default behavior is to not bind to any specific address.
5490 Only change this if you want to have all UDP queries received on
5491 a specific interface/address.
5493 NOTE: udp_incoming_address is used by the ICP, HTCP, and DNS
5494 modules. Altering it will affect all of them in the same manner.
5496 see also; udp_outgoing_address
5498 NOTE, udp_incoming_address and udp_outgoing_address can not
5499 have the same value since they both use the same port.
5502 NAME: udp_outgoing_address
5504 LOC: Config.Addrs.udp_outgoing
5507 udp_outgoing_address is used for UDP packets sent out to other
5510 The default behavior is to not bind to any specific address.
5512 Instead it will use the same socket as udp_incoming_address.
5513 Only change this if you want to have UDP queries sent using another
5514 address than where this Squid listens for UDP queries from other
5517 NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS
5518 modules. Altering it will affect all of them in the same manner.
5520 see also; udp_incoming_address
5522 NOTE, udp_incoming_address and udp_outgoing_address can not
5523 have the same value since they both use the same port.
5530 LOC: Config.onoff.icp_hit_stale
5532 If you want to return ICP_HIT for stale cache objects, set this
5533 option to 'on'. If you have sibling relationships with caches
5534 in other administrative domains, this should be 'off'. If you only
5535 have sibling relationships with caches under your control,
5536 it is probably okay to set this to 'on'.
5537 If set to 'on', your siblings should use the option "allow-miss"
5538 on their cache_peer lines for connecting to you.
5541 NAME: minimum_direct_hops
5544 LOC: Config.minDirectHops
5546 If using the ICMP pinging stuff, do direct fetches for sites
5547 which are no more than this many hops away.
5550 NAME: minimum_direct_rtt
5553 LOC: Config.minDirectRtt
5555 If using the ICMP pinging stuff, do direct fetches for sites
5556 which are no more than this many rtt milliseconds away.
5562 LOC: Config.Netdb.low
5568 LOC: Config.Netdb.high
5570 The low and high water marks for the ICMP measurement
5571 database. These are counts, not percents. The defaults are
5572 900 and 1000. When the high water mark is reached, database
5573 entries will be deleted until the low mark is reached.
5576 NAME: netdb_ping_period
5578 LOC: Config.Netdb.period
5581 The minimum period for measuring a site. There will be at
5582 least this much delay between successive pings to the same
5583 network. The default is five minutes.
5590 LOC: Config.onoff.query_icmp
5592 If you want to ask your peers to include ICMP data in their ICP
5593 replies, enable this option.
5595 If your peer has configured Squid (during compilation) with
5596 '--enable-icmp' that peer will send ICMP pings to origin server
5597 sites of the URLs it receives. If you enable this option the
5598 ICP replies from that peer will include the ICMP data (if available).
5599 Then, when choosing a parent cache, Squid will choose the parent with
5600 the minimal RTT to the origin server. When this happens, the
5601 hierarchy field of the access.log will be
5602 "CLOSEST_PARENT_MISS". This option is off by default.
5605 NAME: test_reachability
5609 LOC: Config.onoff.test_reachability
5611 When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
5612 instead of ICP_MISS if the target host is NOT in the ICMP
5613 database, or has a zero RTT.
5616 NAME: icp_query_timeout
5620 LOC: Config.Timeout.icp_query
5622 Normally Squid will automatically determine an optimal ICP
5623 query timeout value based on the round-trip-time of recent ICP
5624 queries. If you want to override the value determined by
5625 Squid, set this 'icp_query_timeout' to a non-zero value. This
5626 value is specified in MILLISECONDS, so, to use a 2-second
5627 timeout (the old default), you would write:
5629 icp_query_timeout 2000
5632 NAME: maximum_icp_query_timeout
5636 LOC: Config.Timeout.icp_query_max
5638 Normally the ICP query timeout is determined dynamically. But
5639 sometimes it can lead to very large values (say 5 seconds).
5640 Use this option to put an upper limit on the dynamic timeout
5641 value. Do NOT use this option to always use a fixed (instead
5642 of a dynamic) timeout value. To set a fixed timeout see the
5643 'icp_query_timeout' directive.
5646 NAME: minimum_icp_query_timeout
5650 LOC: Config.Timeout.icp_query_min
5652 Normally the ICP query timeout is determined dynamically. But
5653 sometimes it can lead to very small timeouts, even lower than
5654 the normal latency variance on your link due to traffic.
5655 Use this option to put an lower limit on the dynamic timeout
5656 value. Do NOT use this option to always use a fixed (instead
5657 of a dynamic) timeout value. To set a fixed timeout see the
5658 'icp_query_timeout' directive.
5661 NAME: background_ping_rate
5665 LOC: Config.backgroundPingRate
5667 Controls how often the ICP pings are sent to siblings that
5668 have background-ping set.
5672 MULTICAST ICP OPTIONS
5673 -----------------------------------------------------------------------------
5678 LOC: Config.mcast_group_list
5681 This tag specifies a list of multicast groups which your server
5682 should join to receive multicasted ICP queries.
5684 NOTE! Be very careful what you put here! Be sure you
5685 understand the difference between an ICP _query_ and an ICP
5686 _reply_. This option is to be set only if you want to RECEIVE
5687 multicast queries. Do NOT set this option to SEND multicast
5688 ICP (use cache_peer for that). ICP replies are always sent via
5689 unicast, so this option does not affect whether or not you will
5690 receive replies from multicast group members.
5692 You must be very careful to NOT use a multicast address which
5693 is already in use by another group of caches.
5695 If you are unsure about multicast, please read the Multicast
5696 chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
5698 Usage: mcast_groups 239.128.16.128 224.0.1.20
5700 By default, Squid doesn't listen on any multicast groups.
5703 NAME: mcast_miss_addr
5704 IFDEF: MULTICAST_MISS_STREAM
5706 LOC: Config.mcast_miss.addr
5709 If you enable this option, every "cache miss" URL will
5710 be sent out on the specified multicast address.
5712 Do not enable this option unless you are are absolutely
5713 certain you understand what you are doing.
5716 NAME: mcast_miss_ttl
5717 IFDEF: MULTICAST_MISS_STREAM
5719 LOC: Config.mcast_miss.ttl
5722 This is the time-to-live value for packets multicasted
5723 when multicasting off cache miss URLs is enabled. By
5724 default this is set to 'site scope', i.e. 16.
5727 NAME: mcast_miss_port
5728 IFDEF: MULTICAST_MISS_STREAM
5730 LOC: Config.mcast_miss.port
5733 This is the port number to be used in conjunction with
5737 NAME: mcast_miss_encode_key
5738 IFDEF: MULTICAST_MISS_STREAM
5740 LOC: Config.mcast_miss.encode_key
5741 DEFAULT: XXXXXXXXXXXXXXXX
5743 The URLs that are sent in the multicast miss stream are
5744 encrypted. This is the encryption key.
5747 NAME: mcast_icp_query_timeout
5751 LOC: Config.Timeout.mcast_icp_query
5753 For multicast peers, Squid regularly sends out ICP "probes" to
5754 count how many other peers are listening on the given multicast
5755 address. This value specifies how long Squid should wait to
5756 count all the replies. The default is 2000 msec, or 2
5761 INTERNAL ICON OPTIONS
5762 -----------------------------------------------------------------------------
5765 NAME: icon_directory
5767 LOC: Config.icons.directory
5768 DEFAULT: @DEFAULT_ICON_DIR@
5770 Where the icons are stored. These are normally kept in
5774 NAME: global_internal_static
5776 LOC: Config.onoff.global_internal_static
5779 This directive controls is Squid should intercept all requests for
5780 /squid-internal-static/ no matter which host the URL is requesting
5781 (default on setting), or if nothing special should be done for
5782 such URLs (off setting). The purpose of this directive is to make
5783 icons etc work better in complex cache hierarchies where it may
5784 not always be possible for all corners in the cache mesh to reach
5785 the server generating a directory listing.
5788 NAME: short_icon_urls
5790 LOC: Config.icons.use_short_names
5793 If this is enabled Squid will use short URLs for icons.
5794 If disabled it will revert to the old behavior of including
5795 it's own name and port in the URL.
5797 If you run a complex cache hierarchy with a mix of Squid and
5798 other proxies you may need to disable this directive.
5803 -----------------------------------------------------------------------------
5806 NAME: error_directory
5808 LOC: Config.errorDirectory
5811 If you wish to create your own versions of the default
5812 error files to customize them to suit your company copy
5813 the error/template files to another directory and point
5816 WARNING: This option will disable multi-language support
5817 on error pages if used.
5819 The squid developers are interested in making squid available in
5820 a wide variety of languages. If you are making translations for a
5821 language that Squid does not currently provide please consider
5822 contributing your translation back to the project.
5823 http://wiki.squid-cache.org/Translations
5825 The squid developers working on translations are happy to supply drop-in
5826 translated error files in exchange for any new language contributions.
5829 NAME: error_default_language
5830 IFDEF: USE_ERR_LOCALES
5832 LOC: Config.errorDefaultLanguage
5835 Set the default language which squid will send error pages in
5836 if no existing translation matches the clients language
5839 If unset (default) generic English will be used.
5841 The squid developers are interested in making squid available in
5842 a wide variety of languages. If you are interested in making
5843 translations for any language see the squid wiki for details.
5844 http://wiki.squid-cache.org/Translations
5847 NAME: error_log_languages
5848 IFDEF: USE_ERR_LOCALES
5850 LOC: Config.errorLogMissingLanguages
5853 Log to cache.log what languages users are attempting to
5854 auto-negotiate for translations.
5856 Successful negotiations are not logged. Only failures
5857 have meaning to indicate that Squid may need an upgrade
5858 of its error page translations.
5861 NAME: err_page_stylesheet
5863 LOC: Config.errorStylesheet
5864 DEFAULT: @DEFAULT_CONFIG_DIR@/errorpage.css
5866 CSS Stylesheet to pattern the display of Squid default error pages.
5868 For information on CSS see http://www.w3.org/Style/CSS/
5873 LOC: Config.errHtmlText
5876 HTML text to include in error messages. Make this a "mailto"
5877 URL to your admin address, or maybe just a link to your
5878 organizations Web page.
5880 To include this in your error messages, you must rewrite
5881 the error template files (found in the "errors" directory).
5882 Wherever you want the 'err_html_text' line to appear,
5883 insert a %L tag in the error template file.
5886 NAME: email_err_data
5889 LOC: Config.onoff.emailErrData
5892 If enabled, information about the occurred error will be
5893 included in the mailto links of the ERR pages (if %W is set)
5894 so that the email body contains the data.
5895 Syntax is <A HREF="mailto:%w%W">%w</A>
5900 LOC: Config.denyInfoList
5903 Usage: deny_info err_page_name acl
5904 or deny_info http://... acl
5905 or deny_info TCP_RESET acl
5907 This can be used to return a ERR_ page for requests which
5908 do not pass the 'http_access' rules. Squid remembers the last
5909 acl it evaluated in http_access, and if a 'deny_info' line exists
5910 for that ACL Squid returns a corresponding error page.
5912 The acl is typically the last acl on the http_access deny line which
5913 denied access. The exceptions to this rule are:
5914 - When Squid needs to request authentication credentials. It's then
5915 the first authentication related acl encountered
5916 - When none of the http_access lines matches. It's then the last
5917 acl processed on the last http_access line.
5919 NP: If providing your own custom error pages with error_directory
5920 you may also specify them by your custom file name:
5921 Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
5923 Alternatively you can tell Squid to reset the TCP connection
5924 by specifying TCP_RESET.
5926 Or you can specify an error URL or URL pattern. The browsers will
5927 get redirected (302) to the specified URL after formatting tags have
5931 %a - username (if available. Password NOT included)
5934 %E - Error description
5936 %H - Request domain name
5937 %i - Client IP Address
5939 %o - Message result from external ACL helper
5940 %p - Request Port number
5941 %P - Request Protocol name
5942 %R - Request URL path
5943 %T - Timestamp in RFC 1123 format
5944 %U - Full canonical URL from client
5945 (HTTPS URLs terminate with *)
5946 %u - Full canonical URL from client
5947 %w - Admin email from squid.conf
5948 %% - Literal percent (%) code
5953 OPTIONS INFLUENCING REQUEST FORWARDING
5954 -----------------------------------------------------------------------------
5957 NAME: nonhierarchical_direct
5959 LOC: Config.onoff.nonhierarchical_direct
5962 By default, Squid will send any non-hierarchical requests
5963 (matching hierarchy_stoplist or not cacheable request type) direct
5966 If you set this to off, Squid will prefer to send these
5967 requests to parents.
5969 Note that in most configurations, by turning this off you will only
5970 add latency to these request without any improvement in global hit
5973 If you are inside an firewall see never_direct instead of
5979 LOC: Config.onoff.prefer_direct
5982 Normally Squid tries to use parents for most requests. If you for some
5983 reason like it to first try going direct and only use a parent if
5984 going direct fails set this to on.
5986 By combining nonhierarchical_direct off and prefer_direct on you
5987 can set up Squid to use a parent as a backup path if going direct
5990 Note: If you want Squid to use parents for all requests see
5991 the never_direct directive. prefer_direct only modifies how Squid
5992 acts on cacheable requests.
5997 LOC: Config.accessList.AlwaysDirect
6000 Usage: always_direct allow|deny [!]aclname ...
6002 Here you can use ACL elements to specify requests which should
6003 ALWAYS be forwarded by Squid to the origin servers without using
6004 any peers. For example, to always directly forward requests for
6005 local servers ignoring any parents or siblings you may have use
6008 acl local-servers dstdomain my.domain.net
6009 always_direct allow local-servers
6011 To always forward FTP requests directly, use
6014 always_direct allow FTP
6016 NOTE: There is a similar, but opposite option named
6017 'never_direct'. You need to be aware that "always_direct deny
6018 foo" is NOT the same thing as "never_direct allow foo". You
6019 may need to use a deny rule to exclude a more-specific case of
6020 some other rule. Example:
6022 acl local-external dstdomain external.foo.net
6023 acl local-servers dstdomain .foo.net
6024 always_direct deny local-external
6025 always_direct allow local-servers
6027 NOTE: If your goal is to make the client forward the request
6028 directly to the origin server bypassing Squid then this needs
6029 to be done in the client configuration. Squid configuration
6030 can only tell Squid how Squid should fetch the object.
6032 NOTE: This directive is not related to caching. The replies
6033 is cached as usual even if you use always_direct. To not cache
6034 the replies see the 'cache' directive.
6036 This clause supports both fast and slow acl types.
6037 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6042 LOC: Config.accessList.NeverDirect
6045 Usage: never_direct allow|deny [!]aclname ...
6047 never_direct is the opposite of always_direct. Please read
6048 the description for always_direct if you have not already.
6050 With 'never_direct' you can use ACL elements to specify
6051 requests which should NEVER be forwarded directly to origin
6052 servers. For example, to force the use of a proxy for all
6053 requests, except those in your local domain use something like:
6055 acl local-servers dstdomain .foo.net
6056 never_direct deny local-servers
6057 never_direct allow all
6059 or if Squid is inside a firewall and there are local intranet
6060 servers inside the firewall use something like:
6062 acl local-intranet dstdomain .foo.net
6063 acl local-external dstdomain external.foo.net
6064 always_direct deny local-external
6065 always_direct allow local-intranet
6066 never_direct allow all
6068 This clause supports both fast and slow acl types.
6069 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6073 ADVANCED NETWORKING OPTIONS
6074 -----------------------------------------------------------------------------
6077 NAME: incoming_icp_average
6080 LOC: Config.comm_incoming.icp_average
6083 NAME: incoming_http_average
6086 LOC: Config.comm_incoming.http_average
6089 NAME: incoming_dns_average
6092 LOC: Config.comm_incoming.dns_average
6095 NAME: min_icp_poll_cnt
6098 LOC: Config.comm_incoming.icp_min_poll
6101 NAME: min_dns_poll_cnt
6104 LOC: Config.comm_incoming.dns_min_poll
6107 NAME: min_http_poll_cnt
6110 LOC: Config.comm_incoming.http_min_poll
6112 Heavy voodoo here. I can't even believe you are reading this.
6113 Are you crazy? Don't even think about adjusting these unless
6114 you understand the algorithms in comm_select.c first!
6120 LOC: Config.accept_filter
6124 The name of an accept(2) filter to install on Squid's
6125 listen socket(s). This feature is perhaps specific to
6126 FreeBSD and requires support in the kernel.
6128 The 'httpready' filter delays delivering new connections
6129 to Squid until a full HTTP request has been received.
6130 See the accf_http(9) man page for details.
6132 The 'dataready' filter delays delivering new connections
6133 to Squid until there is some data to process.
6134 See the accf_dataready(9) man page for details.
6138 The 'data' filter delays delivering of new connections
6139 to Squid until there is some data to process by TCP_ACCEPT_DEFER.
6140 You may optionally specify a number of seconds to wait by
6141 'data=N' where N is the number of seconds. Defaults to 30
6142 if not specified. See the tcp(7) man page for details.
6145 accept_filter httpready
6150 NAME: client_ip_max_connections
6152 LOC: Config.client_ip_max_connections
6155 Set an absolute limit on the number of connections a single
6156 client IP can use. Any more than this and Squid will begin to drop
6157 new connections from the client until it closes some links.
6159 Note that this is a global limit. It affects all HTTP, HTCP, Gopher and FTP
6160 connections from the client. For finer control use the ACL access controls.
6162 Requires client_db to be enabled (the default).
6164 WARNING: This may noticably slow down traffic received via external proxies
6165 or NAT devices and cause them to rebound error messages back to their clients.
6168 NAME: tcp_recv_bufsize
6172 LOC: Config.tcpRcvBufsz
6174 Size of receive buffer to set for TCP sockets. Probably just
6175 as easy to change your kernel's default. Set to zero to use
6176 the default buffer size.
6181 -----------------------------------------------------------------------------
6188 LOC: Adaptation::Icap::TheConfig.onoff
6191 If you want to enable the ICAP module support, set this to on.
6194 NAME: icap_connect_timeout
6197 LOC: Adaptation::Icap::TheConfig.connect_timeout_raw
6200 This parameter specifies how long to wait for the TCP connect to
6201 the requested ICAP server to complete before giving up and either
6202 terminating the HTTP transaction or bypassing the failure.
6204 The default for optional services is peer_connect_timeout.
6205 The default for essential services is connect_timeout.
6206 If this option is explicitly set, its value applies to all services.
6209 NAME: icap_io_timeout
6213 LOC: Adaptation::Icap::TheConfig.io_timeout_raw
6216 This parameter specifies how long to wait for an I/O activity on
6217 an established, active ICAP connection before giving up and
6218 either terminating the HTTP transaction or bypassing the
6221 The default is read_timeout.
6224 NAME: icap_service_failure_limit
6225 COMMENT: limit [in memory-depth time-units]
6226 TYPE: icap_service_failure_limit
6228 LOC: Adaptation::Icap::TheConfig
6231 The limit specifies the number of failures that Squid tolerates
6232 when establishing a new TCP connection with an ICAP service. If
6233 the number of failures exceeds the limit, the ICAP service is
6234 not used for new ICAP requests until it is time to refresh its
6237 A negative value disables the limit. Without the limit, an ICAP
6238 service will not be considered down due to connectivity failures
6239 between ICAP OPTIONS requests.
6241 Squid forgets ICAP service failures older than the specified
6242 value of memory-depth. The memory fading algorithm
6243 is approximate because Squid does not remember individual
6244 errors but groups them instead, splitting the option
6245 value into ten time slots of equal length.
6247 When memory-depth is 0 and by default this option has no
6248 effect on service failure expiration.
6250 Squid always forgets failures when updating service settings
6251 using an ICAP OPTIONS transaction, regardless of this option
6255 # suspend service usage after 10 failures in 5 seconds:
6256 icap_service_failure_limit 10 in 5 seconds
6259 NAME: icap_service_revival_delay
6262 LOC: Adaptation::Icap::TheConfig.service_revival_delay
6265 The delay specifies the number of seconds to wait after an ICAP
6266 OPTIONS request failure before requesting the options again. The
6267 failed ICAP service is considered "down" until fresh OPTIONS are
6270 The actual delay cannot be smaller than the hardcoded minimum
6271 delay of 30 seconds.
6274 NAME: icap_preview_enable
6278 LOC: Adaptation::Icap::TheConfig.preview_enable
6281 The ICAP Preview feature allows the ICAP server to handle the
6282 HTTP message by looking only at the beginning of the message body
6283 or even without receiving the body at all. In some environments,
6284 previews greatly speedup ICAP processing.
6286 During an ICAP OPTIONS transaction, the server may tell Squid what
6287 HTTP messages should be previewed and how big the preview should be.
6288 Squid will not use Preview if the server did not request one.
6290 To disable ICAP Preview for all ICAP services, regardless of
6291 individual ICAP server OPTIONS responses, set this option to "off".
6293 icap_preview_enable off
6296 NAME: icap_preview_size
6299 LOC: Adaptation::Icap::TheConfig.preview_size
6302 The default size of preview data to be sent to the ICAP server.
6303 -1 means no preview. This value might be overwritten on a per server
6304 basis by OPTIONS requests.
6307 NAME: icap_206_enable
6311 LOC: Adaptation::Icap::TheConfig.allow206_enable
6314 206 (Partial Content) responses is an ICAP extension that allows the
6315 ICAP agents to optionally combine adapted and original HTTP message
6316 content. The decision to combine is postponed until the end of the
6317 ICAP response. Squid supports Partial Content extension by default.
6319 Activation of the Partial Content extension is negotiated with each
6320 ICAP service during OPTIONS exchange. Most ICAP servers should handle
6321 negotation correctly even if they do not support the extension, but
6322 some might fail. To disable Partial Content support for all ICAP
6323 services and to avoid any negotiation, set this option to "off".
6329 NAME: icap_default_options_ttl
6332 LOC: Adaptation::Icap::TheConfig.default_options_ttl
6335 The default TTL value for ICAP OPTIONS responses that don't have
6336 an Options-TTL header.
6339 NAME: icap_persistent_connections
6343 LOC: Adaptation::Icap::TheConfig.reuse_connections
6346 Whether or not Squid should use persistent connections to
6350 NAME: icap_send_client_ip
6354 LOC: Adaptation::Icap::TheConfig.send_client_ip
6357 This adds the header "X-Client-IP" to ICAP requests.
6360 NAME: icap_send_client_username
6364 LOC: Adaptation::Icap::TheConfig.send_client_username
6367 This sends authenticated HTTP client username (if available) to
6368 the ICAP service. The username value is encoded based on the
6369 icap_client_username_encode option and is sent using the header
6370 specified by the icap_client_username_header option.
6373 NAME: icap_client_username_header
6376 LOC: Adaptation::Icap::TheConfig.client_username_header
6377 DEFAULT: X-Client-Username
6379 ICAP request header name to use for send_client_username.
6382 NAME: icap_client_username_encode
6386 LOC: Adaptation::Icap::TheConfig.client_username_encode
6389 Whether to base64 encode the authenticated client username.
6393 TYPE: icap_service_type
6395 LOC: Adaptation::Icap::TheConfig
6398 Defines a single ICAP service using the following format:
6400 icap_service service_name vectoring_point [options] service_url
6403 an opaque identifier which must be unique in squid.conf
6405 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
6406 This specifies at which point of transaction processing the
6407 ICAP service should be activated. *_postcache vectoring points
6408 are not yet supported.
6410 service_url: icap://servername:port/servicepath
6411 ICAP server and service location.
6413 ICAP does not allow a single service to handle both REQMOD and RESPMOD
6414 transactions. Squid does not enforce that requirement. You can specify
6415 services with the same service_url and different vectoring_points. You
6416 can even specify multiple identical services as long as their
6417 service_names differ.
6420 Service options are separated by white space. ICAP services support
6421 the following name=value options:
6424 If set to 'on' or '1', the ICAP service is treated as
6425 optional. If the service cannot be reached or malfunctions,
6426 Squid will try to ignore any errors and process the message as
6427 if the service was not enabled. No all ICAP errors can be
6428 bypassed. If set to 0, the ICAP service is treated as
6429 essential and all ICAP errors will result in an error page
6430 returned to the HTTP client.
6432 Bypass is off by default: services are treated as essential.
6435 If set to 'on' or '1', the ICAP service is allowed to
6436 dynamically change the current message adaptation plan by
6437 returning a chain of services to be used next. The services
6438 are specified using the X-Next-Services ICAP response header
6439 value, formatted as a comma-separated list of service names.
6440 Each named service should be configured in squid.conf and
6441 should have the same method and vectoring point as the current
6442 ICAP transaction. Services violating these rules are ignored.
6443 An empty X-Next-Services value results in an empty plan which
6444 ends the current adaptation.
6446 Routing is not allowed by default: the ICAP X-Next-Services
6447 response header is ignored.
6450 Only has effect on split-stack systems. The default on those systems
6451 is to use IPv4-only connections. When set to 'on' this option will
6452 make Squid use IPv6-only connections to contact this ICAP service.
6454 Older icap_service format without optional named parameters is
6455 deprecated but supported for backward compatibility.
6458 icap_service svcBlocker reqmod_precache bypass=0 icap://icap1.mydomain.net:1344/reqmod
6459 icap_service svcLogger reqmod_precache routing=on icap://icap2.mydomain.net:1344/respmod
6463 TYPE: icap_class_type
6468 This deprecated option was documented to define an ICAP service
6469 chain, even though it actually defined a set of similar, redundant
6470 services, and the chains were not supported.
6472 To define a set of redundant services, please use the
6473 adaptation_service_set directive. For service chains, use
6474 adaptation_service_chain.
6478 TYPE: icap_access_type
6483 This option is deprecated. Please use adaptation_access, which
6484 has the same ICAP functionality, but comes with better
6485 documentation, and eCAP support.
6490 -----------------------------------------------------------------------------
6497 LOC: Adaptation::Ecap::TheConfig.onoff
6500 Controls whether eCAP support is enabled.
6504 TYPE: ecap_service_type
6506 LOC: Adaptation::Ecap::TheConfig
6509 Defines a single eCAP service
6511 ecap_service servicename vectoring_point bypass service_url
6513 vectoring_point = reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
6514 This specifies at which point of transaction processing the
6515 eCAP service should be activated. *_postcache vectoring points
6516 are not yet supported.
6518 If set to 1, the eCAP service is treated as optional. If the
6519 service cannot be reached or malfunctions, Squid will try to
6520 ignore any errors and process the message as if the service
6521 was not enabled. No all eCAP errors can be bypassed.
6522 If set to 0, the eCAP service is treated as essential and all
6523 eCAP errors will result in an error page returned to the
6525 service_url = ecap://vendor/service_name?custom&cgi=style¶meters=optional
6528 ecap_service service_1 reqmod_precache 0 ecap://filters-R-us/leakDetector?on_error=block
6529 ecap_service service_2 respmod_precache 1 icap://filters-R-us/virusFilter?config=/etc/vf.cfg
6532 NAME: loadable_modules
6534 IFDEF: USE_LOADABLE_MODULES
6535 LOC: Config.loadable_module_names
6538 Instructs Squid to load the specified dynamic module(s) or activate
6539 preloaded module(s).
6541 loadable_modules @DEFAULT_PREFIX@/lib/MinimalAdapter.so
6545 MESSAGE ADAPTATION OPTIONS
6546 -----------------------------------------------------------------------------
6549 NAME: adaptation_service_set
6550 TYPE: adaptation_service_set_type
6551 IFDEF: USE_ADAPTATION
6556 Configures an ordered set of similar, redundant services. This is
6557 useful when hot standby or backup adaptation servers are available.
6559 adaptation_service_set set_name service_name1 service_name2 ...
6561 The named services are used in the set declaration order. The first
6562 applicable adaptation service from the set is used first. The next
6563 applicable service is tried if and only if the transaction with the
6564 previous service fails and the message waiting to be adapted is still
6567 When adaptation starts, broken services are ignored as if they were
6568 not a part of the set. A broken service is a down optional service.
6570 The services in a set must be attached to the same vectoring point
6571 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
6573 If all services in a set are optional then adaptation failures are
6574 bypassable. If all services in the set are essential, then a
6575 transaction failure with one service may still be retried using
6576 another service from the set, but when all services fail, the master
6577 transaction fails as well.
6579 A set may contain a mix of optional and essential services, but that
6580 is likely to lead to surprising results because broken services become
6581 ignored (see above), making previously bypassable failures fatal.
6582 Technically, it is the bypassability of the last failed service that
6585 See also: adaptation_access adaptation_service_chain
6588 adaptation_service_set svcBlocker urlFilterPrimary urlFilterBackup
6589 adaptation service_set svcLogger loggerLocal loggerRemote
6592 NAME: adaptation_service_chain
6593 TYPE: adaptation_service_chain_type
6594 IFDEF: USE_ADAPTATION
6599 Configures a list of complementary services that will be applied
6600 one-by-one, forming an adaptation chain or pipeline. This is useful
6601 when Squid must perform different adaptations on the same message.
6603 adaptation_service_chain chain_name service_name1 svc_name2 ...
6605 The named services are used in the chain declaration order. The first
6606 applicable adaptation service from the chain is used first. The next
6607 applicable service is applied to the successful adaptation results of
6608 the previous service in the chain.
6610 When adaptation starts, broken services are ignored as if they were
6611 not a part of the chain. A broken service is a down optional service.
6613 Request satisfaction terminates the adaptation chain because Squid
6614 does not currently allow declaration of RESPMOD services at the
6615 "reqmod_precache" vectoring point (see icap_service or ecap_service).
6617 The services in a chain must be attached to the same vectoring point
6618 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
6620 A chain may contain a mix of optional and essential services. If an
6621 essential adaptation fails (or the failure cannot be bypassed for
6622 other reasons), the master transaction fails. Otherwise, the failure
6623 is bypassed as if the failed adaptation service was not in the chain.
6625 See also: adaptation_access adaptation_service_set
6628 adaptation_service_chain svcRequest requestLogger urlFilter leakDetector
6631 NAME: adaptation_access
6632 TYPE: adaptation_access_type
6633 IFDEF: USE_ADAPTATION
6637 Sends an HTTP transaction to an ICAP or eCAP adaptation service.
6639 adaptation_access service_name allow|deny [!]aclname...
6640 adaptation_access set_name allow|deny [!]aclname...
6642 At each supported vectoring point, the adaptation_access
6643 statements are processed in the order they appear in this
6644 configuration file. Statements pointing to the following services
6645 are ignored (i.e., skipped without checking their ACL):
6647 - services serving different vectoring points
6648 - "broken-but-bypassable" services
6649 - "up" services configured to ignore such transactions
6650 (e.g., based on the ICAP Transfer-Ignore header).
6652 When a set_name is used, all services in the set are checked
6653 using the same rules, to find the first applicable one. See
6654 adaptation_service_set for details.
6656 If an access list is checked and there is a match, the
6657 processing stops: For an "allow" rule, the corresponding
6658 adaptation service is used for the transaction. For a "deny"
6659 rule, no adaptation service is activated.
6661 It is currently not possible to apply more than one adaptation
6662 service at the same vectoring point to the same HTTP transaction.
6664 See also: icap_service and ecap_service
6667 adaptation_access service_1 allow all
6670 NAME: adaptation_service_iteration_limit
6672 IFDEF: USE_ADAPTATION
6673 LOC: Adaptation::Config::service_iteration_limit
6676 Limits the number of iterations allowed when applying adaptation
6677 services to a message. If your longest adaptation set or chain
6678 may have more than 16 services, increase the limit beyond its
6679 default value of 16. If detecting infinite iteration loops sooner
6680 is critical, make the iteration limit match the actual number
6681 of services in your longest adaptation set or chain.
6683 Infinite adaptation loops are most likely with routing services.
6685 See also: icap_service routing=1
6688 NAME: adaptation_masterx_shared_names
6690 IFDEF: USE_ADAPTATION
6691 LOC: Adaptation::Config::masterx_shared_name
6694 For each master transaction (i.e., the HTTP request and response
6695 sequence, including all related ICAP and eCAP exchanges), Squid
6696 maintains a table of metadata. The table entries are (name, value)
6697 pairs shared among eCAP and ICAP exchanges. The table is destroyed
6698 with the master transaction.
6700 This option specifies the table entry names that Squid must accept
6701 from and forward to the adaptation transactions.
6703 An ICAP REQMOD or RESPMOD transaction may set an entry in the
6704 shared table by returning an ICAP header field with a name
6705 specified in adaptation_masterx_shared_names. Squid will store
6706 and forward that ICAP header field to subsequent ICAP
6707 transactions within the same master transaction scope.
6709 Only one shared entry name is supported at this time.
6712 # share authentication information among ICAP services
6713 adaptation_masterx_shared_names X-Subscriber-ID
6719 LOC: Adaptation::Icap::TheConfig.repeat
6720 DEFAULT_IF_NONE: deny all
6722 This ACL determines which retriable ICAP transactions are
6723 retried. Transactions that received a complete ICAP response
6724 and did not have to consume or produce HTTP bodies to receive
6725 that response are usually retriable.
6727 icap_retry allow|deny [!]aclname ...
6729 Squid automatically retries some ICAP I/O timeouts and errors
6730 due to persistent connection race conditions.
6732 See also: icap_retry_limit
6735 NAME: icap_retry_limit
6738 LOC: Adaptation::Icap::TheConfig.repeat_limit
6741 Limits the number of retries allowed. When set to zero (default),
6742 no retries are allowed.
6744 Communication errors due to persistent connection race
6745 conditions are unavoidable, automatically retried, and do not
6746 count against this limit.
6748 See also: icap_retry
6754 -----------------------------------------------------------------------------
6757 NAME: check_hostnames
6760 LOC: Config.onoff.check_hostnames
6762 For security and stability reasons Squid can check
6763 hostnames for Internet standard RFC compliance. If you want
6764 Squid to perform these checks turn this directive on.
6767 NAME: allow_underscore
6770 LOC: Config.onoff.allow_underscore
6772 Underscore characters is not strictly allowed in Internet hostnames
6773 but nevertheless used by many sites. Set this to off if you want
6774 Squid to be strict about the standard.
6775 This check is performed only when check_hostnames is set to on.
6778 NAME: cache_dns_program
6780 IFDEF: USE_DNSSERVERS
6781 DEFAULT: @DEFAULT_DNSSERVER@
6782 LOC: Config.Program.dnsserver
6784 Specify the location of the executable for dnslookup process.
6788 TYPE: HelperChildConfig
6789 IFDEF: USE_DNSSERVERS
6790 DEFAULT: 32 startup=1 idle=1
6791 LOC: Config.dnsChildren
6793 The maximum number of processes spawn to service DNS name lookups.
6794 If you limit it too few Squid will have to wait for them to process
6795 a backlog of requests, slowing it down. If you allow too many they
6796 will use RAM and other system resources noticably.
6797 The maximum this may be safely set to is 32.
6799 The startup= and idle= options allow some measure of skew in your
6804 Sets a minimum of how many processes are to be spawned when Squid
6805 starts or reconfigures. When set to zero the first request will
6806 cause spawning of the first child process to handle it.
6808 Starting too few will cause an initial slowdown in traffic as Squid
6809 attempts to simultaneously spawn enough processes to cope.
6813 Sets a minimum of how many processes Squid is to try and keep available
6814 at all times. When traffic begins to rise above what the existing
6815 processes can handle this many more will be spawned up to the maximum
6816 configured. A minimum setting of 1 is required.
6819 NAME: dns_retransmit_interval
6822 LOC: Config.Timeout.idns_retransmit
6823 IFDEF: !USE_DNSSERVERS
6825 Initial retransmit interval for DNS queries. The interval is
6826 doubled each time all configured DNS servers have been tried.
6832 LOC: Config.Timeout.idns_query
6833 IFDEF: !USE_DNSSERVERS
6835 DNS Query timeout. If no response is received to a DNS query
6836 within this time all DNS servers for the queried domain
6837 are assumed to be unavailable.
6840 NAME: dns_packet_max
6843 LOC: Config.dns.packet_max
6844 IFDEF: !USE_DNSSERVERS
6846 Maximum number of bytes packet size to advertise via EDNS.
6847 Set to "none" to disable EDNS large packet support.
6849 For legacy reasons DNS UDP replies will default to 512 bytes which
6850 is too small for many responses. EDNS provides a means for Squid to
6851 negotiate receiving larger responses back immediately without having
6852 to failover with repeat requests. Responses larger than this limit
6853 will retain the old behaviour of failover to TCP DNS.
6855 Squid has no real fixed limit internally, but allowing packet sizes
6856 over 1500 bytes requires network jumbogram support and is usually not
6859 WARNING: The RFC also indicates that some older resolvers will reply
6860 with failure of the whole request if the extension is added. Some
6861 resolvers have already been identified which will reply with mangled
6862 EDNS response on occasion. Usually in response to many-KB jumbogram
6863 sizes being advertised by Squid.
6864 Squid will currently treat these both as an unable-to-resolve domain
6865 even if it would be resolvable without EDNS.
6872 LOC: Config.onoff.res_defnames
6874 Normally the RES_DEFNAMES resolver option is disabled
6875 (see res_init(3)). This prevents caches in a hierarchy
6876 from interpreting single-component hostnames locally. To allow
6877 Squid to handle single-component names, enable this option.
6880 NAME: dns_nameservers
6883 LOC: Config.dns_nameservers
6885 Use this if you want to specify a list of DNS name servers
6886 (IP addresses) to use instead of those given in your
6887 /etc/resolv.conf file.
6888 On Windows platforms, if no value is specified here or in
6889 the /etc/resolv.conf file, the list of DNS name servers are
6890 taken from the Windows registry, both static and dynamic DHCP
6891 configurations are supported.
6893 Example: dns_nameservers 10.0.0.1 192.172.0.4
6898 DEFAULT: @DEFAULT_HOSTS@
6899 LOC: Config.etcHostsPath
6901 Location of the host-local IP name-address associations
6902 database. Most Operating Systems have such a file on different
6904 - Un*X & Linux: /etc/hosts
6905 - Windows NT/2000: %SystemRoot%\system32\drivers\etc\hosts
6906 (%SystemRoot% value install default is c:\winnt)
6907 - Windows XP/2003: %SystemRoot%\system32\drivers\etc\hosts
6908 (%SystemRoot% value install default is c:\windows)
6909 - Windows 9x/Me: %windir%\hosts
6910 (%windir% value is usually c:\windows)
6911 - Cygwin: /etc/hosts
6913 The file contains newline-separated definitions, in the
6914 form ip_address_in_dotted_form name [name ...] names are
6915 whitespace-separated. Lines beginning with an hash (#)
6916 character are comments.
6918 The file is checked at startup and upon configuration.
6919 If set to 'none', it won't be checked.
6920 If append_domain is used, that domain will be added to
6921 domain-local (i.e. not containing any dot character) host
6927 LOC: Config.appendDomain
6930 Appends local domain name to hostnames without any dots in
6931 them. append_domain must begin with a period.
6933 Be warned there are now Internet names with no dots in
6934 them using only top-domain names, so setting this may
6935 cause some Internet sites to become unavailable.
6938 append_domain .yourdomain.com
6941 NAME: ignore_unknown_nameservers
6943 LOC: Config.onoff.ignore_unknown_nameservers
6946 By default Squid checks that DNS responses are received
6947 from the same IP addresses they are sent to. If they
6948 don't match, Squid ignores the response and writes a warning
6949 message to cache.log. You can allow responses from unknown
6950 nameservers by setting this option to 'off'.
6953 NAME: dns_v4_fallback
6956 LOC: Config.onoff.dns_require_A
6958 Standard practice with DNS is to lookup either A or AAAA records
6959 and use the results if it succeeds. Only looking up the other if
6960 the first attempt fails or otherwise produces no results.
6962 That policy however will cause squid to produce error pages for some
6963 servers that advertise AAAA but are unreachable over IPv6.
6965 If this is ON squid will always lookup both AAAA and A, using both.
6966 If this is OFF squid will lookup AAAA and only try A if none found.
6968 WARNING: There are some possibly unwanted side-effects with this on:
6969 *) Doubles the load placed by squid on the DNS network.
6970 *) May negatively impact connection delay times.
6974 COMMENT: (number of entries)
6977 LOC: Config.ipcache.size
6984 LOC: Config.ipcache.low
6991 LOC: Config.ipcache.high
6993 The size, low-, and high-water marks for the IP cache.
6996 NAME: fqdncache_size
6997 COMMENT: (number of entries)
7000 LOC: Config.fqdncache.size
7002 Maximum number of FQDN cache entries.
7007 -----------------------------------------------------------------------------
7014 LOC: Config.onoff.mem_pools
7016 If set, Squid will keep pools of allocated (but unused) memory
7017 available for future use. If memory is a premium on your
7018 system and you believe your malloc library outperforms Squid
7019 routines, disable this.
7022 NAME: memory_pools_limit
7026 LOC: Config.MemPools.limit
7028 Used only with memory_pools on:
7029 memory_pools_limit 50 MB
7031 If set to a non-zero value, Squid will keep at most the specified
7032 limit of allocated (but unused) memory in memory pools. All free()
7033 requests that exceed this limit will be handled by your malloc
7034 library. Squid does not pre-allocate any memory, just safe-keeps
7035 objects that otherwise would be free()d. Thus, it is safe to set
7036 memory_pools_limit to a reasonably high value even if your
7037 configuration will use less memory.
7039 If set to none, Squid will keep all memory it can. That is, there
7040 will be no limit on the total amount of memory used for safe-keeping.
7042 To disable memory allocation optimization, do not set
7043 memory_pools_limit to 0 or none. Set memory_pools to "off" instead.
7045 An overhead for maintaining memory pools is not taken into account
7046 when the limit is checked. This overhead is close to four bytes per
7047 object kept. However, pools may actually _save_ memory because of
7048 reduced memory thrashing in your malloc library.
7052 COMMENT: on|off|transparent|truncate|delete
7055 LOC: opt_forwarded_for
7057 If set to "on", Squid will append your client's IP address
7058 in the HTTP requests it forwards. By default it looks like:
7060 X-Forwarded-For: 192.1.2.3
7062 If set to "off", it will appear as
7064 X-Forwarded-For: unknown
7066 If set to "transparent", Squid will not alter the
7067 X-Forwarded-For header in any way.
7069 If set to "delete", Squid will delete the entire
7070 X-Forwarded-For header.
7072 If set to "truncate", Squid will remove all existing
7073 X-Forwarded-For entries, and place itself as the sole entry.
7076 NAME: cachemgr_passwd
7077 TYPE: cachemgrpasswd
7079 LOC: Config.passwd_list
7081 Specify passwords for cachemgr operations.
7083 Usage: cachemgr_passwd password action action ...
7085 Some valid actions are (see cache manager menu for a full list):
7125 * Indicates actions which will not be performed without a
7126 valid password, others can be performed if not listed here.
7128 To disable an action, set the password to "disable".
7129 To allow performing an action without a password, set the
7132 Use the keyword "all" to set the same password for all actions.
7135 cachemgr_passwd secret shutdown
7136 cachemgr_passwd lesssssssecret info stats/objects
7137 cachemgr_passwd disable all
7144 LOC: Config.onoff.client_db
7146 If you want to disable collecting per-client statistics,
7147 turn off client_db here.
7150 NAME: refresh_all_ims
7154 LOC: Config.onoff.refresh_all_ims
7156 When you enable this option, squid will always check
7157 the origin server for an update when a client sends an
7158 If-Modified-Since request. Many browsers use IMS
7159 requests when the user requests a reload, and this
7160 ensures those clients receive the latest version.
7162 By default (off), squid may return a Not Modified response
7163 based on the age of the cached version.
7166 NAME: reload_into_ims
7167 IFDEF: USE_HTTP_VIOLATIONS
7171 LOC: Config.onoff.reload_into_ims
7173 When you enable this option, client no-cache or ``reload''
7174 requests will be changed to If-Modified-Since requests.
7175 Doing this VIOLATES the HTTP standard. Enabling this
7176 feature could make you liable for problems which it
7179 see also refresh_pattern for a more selective approach.
7182 NAME: connect_retries
7184 LOC: Config.connect_retries
7187 This sets the maximum number of connection attempts made for each
7188 TCP connection. The connect_retries attempts must all still
7189 complete within the connection timeout period.
7191 The default is not to re-try if the first connection attempt fails.
7192 The (not recommended) maximum is 10 tries.
7194 A warning message will be generated if it is set to a too-high
7195 value and the configured value will be over-ridden.
7197 Note: These re-tries are in addition to forward_max_tries
7198 which limit how many different addresses may be tried to find
7202 NAME: retry_on_error
7204 LOC: Config.retry.onerror
7207 If set to on Squid will automatically retry requests when
7208 receiving an error response. This is mainly useful if you
7209 are in a complex cache hierarchy to work around access
7213 NAME: as_whois_server
7215 LOC: Config.as_whois_server
7216 DEFAULT: whois.ra.net
7218 WHOIS server to query for AS numbers. NOTE: AS numbers are
7219 queried only when Squid starts up, not for every request.
7224 LOC: Config.onoff.offline
7227 Enable this option and Squid will never try to validate cached
7231 NAME: uri_whitespace
7232 TYPE: uri_whitespace
7233 LOC: Config.uri_whitespace
7236 What to do with requests that have whitespace characters in the
7239 strip: The whitespace characters are stripped out of the URL.
7240 This is the behavior recommended by RFC2396.
7241 deny: The request is denied. The user receives an "Invalid
7243 allow: The request is allowed and the URI is not changed. The
7244 whitespace characters remain in the URI. Note the
7245 whitespace is passed to redirector processes if they
7247 encode: The request is allowed and the whitespace characters are
7248 encoded according to RFC1738. This could be considered
7249 a violation of the HTTP/1.1
7250 RFC because proxies are not allowed to rewrite URI's.
7251 chop: The request is allowed and the URI is chopped at the
7252 first whitespace. This might also be considered a
7258 LOC: Config.chroot_dir
7261 Specifies a directory where Squid should do a chroot() while
7262 initializing. This also causes Squid to fully drop root
7263 privileges after initializing. This means, for example, if you
7264 use a HTTP port less than 1024 and try to reconfigure, you may
7265 get an error saying that Squid can not open the port.
7268 NAME: balance_on_multiple_ip
7270 LOC: Config.onoff.balance_on_multiple_ip
7273 Modern IP resolvers in squid sort lookup results by preferred access.
7274 By default squid will use these IP in order and only rotates to
7275 the next listed when the most preffered fails.
7277 Some load balancing servers based on round robin DNS have been
7278 found not to preserve user session state across requests
7279 to different IP addresses.
7281 Enabling this directive Squid rotates IP's per request.
7284 NAME: pipeline_prefetch
7286 LOC: Config.onoff.pipeline_prefetch
7289 To boost the performance of pipelined requests to closer
7290 match that of a non-proxied environment Squid can try to fetch
7291 up to two requests in parallel from a pipeline.
7293 Defaults to off for bandwidth management and access logging
7297 NAME: high_response_time_warning
7300 LOC: Config.warnings.high_rptm
7303 If the one-minute median response time exceeds this value,
7304 Squid prints a WARNING with debug level 0 to get the
7305 administrators attention. The value is in milliseconds.
7308 NAME: high_page_fault_warning
7310 LOC: Config.warnings.high_pf
7313 If the one-minute average page fault rate exceeds this
7314 value, Squid prints a WARNING with debug level 0 to get
7315 the administrators attention. The value is in page faults
7319 NAME: high_memory_warning
7321 LOC: Config.warnings.high_memory
7324 If the memory usage (as determined by mallinfo) exceeds
7325 this amount, Squid prints a WARNING with debug level 0 to get
7326 the administrators attention.
7329 NAME: sleep_after_fork
7330 COMMENT: (microseconds)
7332 LOC: Config.sleep_after_fork
7335 When this is set to a non-zero value, the main Squid process
7336 sleeps the specified number of microseconds after a fork()
7337 system call. This sleep may help the situation where your
7338 system reports fork() failures due to lack of (virtual)
7339 memory. Note, however, if you have a lot of child
7340 processes, these sleep delays will add up and your
7341 Squid will not service requests for some amount of time
7342 until all the child processes have been started.
7343 On Windows value less then 1000 (1 milliseconds) are
7347 NAME: windows_ipaddrchangemonitor
7348 IFDEF: _SQUID_MSWIN_
7352 LOC: Config.onoff.WIN32_IpAddrChangeMonitor
7354 On Windows Squid by default will monitor IP address changes and will
7355 reconfigure itself after any detected event. This is very useful for
7356 proxies connected to internet with dial-up interfaces.
7357 In some cases (a Proxy server acting as VPN gateway is one) it could be
7358 desiderable to disable this behaviour setting this to 'off'.
7359 Note: after changing this, Squid service must be restarted.
7364 IFDEF: USE_SQUID_EUI
7366 LOC: Eui::TheConfig.euiLookup
7368 Whether to lookup the EUI or MAC address of a connected client.
7371 NAME: max_filedescriptors max_filedesc
7374 LOC: Config.max_filedescriptors
7376 The maximum number of filedescriptors supported.
7378 The default "0" means Squid inherits the current ulimit setting.
7380 Note: Changing this requires a restart of Squid. Also
7381 not all comm loops supports large values.
7389 Number of main Squid processes or "workers" to fork and maintain.
7390 0: "no daemon" mode, like running "squid -N ..."
7391 1: "no SMP" mode, start one main Squid process daemon (default)
7392 N: start N main Squid process daemons (i.e., SMP mode)
7394 In SMP mode, each worker does nearly all what a single Squid daemon
7395 does (e.g., listen on http_port and forward HTTP requests).
7398 NAME: cpu_affinity_map
7399 TYPE: CpuAffinityMap
7400 LOC: Config.cpuAffinityMap
7403 Usage: cpu_affinity_map process_numbers=P1,P2,... cores=C1,C2,...
7405 Sets 1:1 mapping between Squid processes and CPU cores. For example,
7407 cpu_affinity_map process_numbers=1,2,3,4 cores=1,3,5,7
7409 affects processes 1 through 4 only and places them on the first
7410 four even cores, starting with core #1.
7412 CPU cores are numbered starting from 1. Requires support for
7413 sched_getaffinity(2) and sched_setaffinity(2) system calls.
7415 Multiple cpu_affinity_map options are merged.