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 -----------------------------------------------------------------------------
179 This is used to define parameters for the various authentication
180 schemes supported by Squid.
182 format: auth_param scheme parameter [setting]
184 The order in which authentication schemes are presented to the client is
185 dependent on the order the scheme first appears in config file. IE
186 has a bug (it's not RFC 2617 compliant) in that it will use the basic
187 scheme if basic is the first entry presented, even if more secure
188 schemes are presented. For now use the order in the recommended
189 settings section below. If other browsers have difficulties (don't
190 recognize the schemes offered even if you are using basic) either
191 put basic first, or disable the other schemes (by commenting out their
194 Once an authentication scheme is fully configured, it can only be
195 shutdown by shutting squid down and restarting. Changes can be made on
196 the fly and activated with a reconfigure. I.E. You can change to a
197 different helper, but not unconfigure the helper completely.
199 Please note that while this directive defines how Squid processes
200 authentication it does not automatically activate authentication.
201 To use authentication you must in addition make use of ACLs based
202 on login name in http_access (proxy_auth, proxy_auth_regex or
203 external with %LOGIN used in the format tag). The browser will be
204 challenged for authentication on the first such acl encountered
205 in http_access processing and will also be re-challenged for new
206 login credentials if the request is being denied by a proxy_auth
209 WARNING: authentication can't be used in a transparently intercepting
210 proxy as the client then thinks it is talking to an origin server and
211 not the proxy. This is a limitation of bending the TCP/IP protocol to
212 transparently intercepting port 80, not a limitation in Squid.
213 Ports flagged 'transparent', 'intercept', or 'tproxy' have
214 authentication disabled.
216 === Parameters for the basic scheme follow. ===
219 Specify the command for the external authenticator. Such a program
220 reads a line containing "username password" and replies "OK" or
221 "ERR" in an endless loop. "ERR" responses may optionally be followed
222 by a error description available as %m in the returned error page.
223 If you use an authenticator, make sure you have 1 acl of type
226 By default, the basic authentication scheme is not used unless a
227 program is specified.
229 If you want to use the traditional NCSA proxy authentication, set
230 this line to something like
232 auth_param basic program @DEFAULT_PREFIX@/libexec/ncsa_auth @DEFAULT_PREFIX@/etc/passwd
235 HTTP uses iso-latin-1 as characterset, while some authentication
236 backends such as LDAP expects UTF-8. If this is set to on Squid will
237 translate the HTTP iso-latin-1 charset to UTF-8 before sending the
238 username & password to the helper.
240 "children" numberofchildren [startup=N] [idle=N] [concurrency=N]
241 The maximum number of authenticator processes to spawn. If you start too few
242 Squid will have to wait for them to process a backlog of credential
243 verifications, slowing it down. When password verifications are
244 done via a (slow) network you are likely to need lots of
245 authenticator processes.
247 The startup= and idle= options permit some skew in the exact amount
248 run. A minimum of startup=N will begin during startup and reconfigure.
249 Squid will start more in groups of up to idle=N in an attempt to meet
250 traffic needs and to keep idle=N free above those traffic needs up to
253 The concurrency= option sets the number of concurrent requests the
254 helper can process. The default of 0 is used for helpers who only
255 supports one request at a time. Setting this to a number greater than
256 0 changes the protocol used to include a channel number first on the
257 request/response line, allowing multiple requests to be sent to the
258 same helper in parallell without wating for the response.
259 Must not be set unless it's known the helper supports this.
261 auth_param basic children 20 startup=0 idle=1
264 Specifies the realm name which is to be reported to the
265 client for the basic proxy authentication scheme (part of
266 the text the user will see when prompted their username and
267 password). There is no default.
268 auth_param basic realm Squid proxy-caching web server
270 "credentialsttl" timetolive
271 Specifies how long squid assumes an externally validated
272 username:password pair is valid for - in other words how
273 often the helper program is called for that user. Set this
274 low to force revalidation with short lived passwords. Note
275 setting this high does not impact your susceptibility
276 to replay attacks unless you are using an one-time password
277 system (such as SecureID). If you are using such a system,
278 you will be vulnerable to replay attacks unless you also
279 use the max_user_ip ACL in an http_access rule.
281 "casesensitive" on|off
282 Specifies if usernames are case sensitive. Most user databases are
283 case insensitive allowing the same username to be spelled using both
284 lower and upper case letters, but some are case sensitive. This
285 makes a big difference for user_max_ip ACL processing and similar.
286 auth_param basic casesensitive off
288 === Parameters for the digest scheme follow ===
291 Specify the command for the external authenticator. Such
292 a program reads a line containing "username":"realm" and
293 replies with the appropriate H(A1) value hex encoded or
294 ERR if the user (or his H(A1) hash) does not exists.
295 See rfc 2616 for the definition of H(A1).
296 "ERR" responses may optionally be followed by a error description
297 available as %m in the returned error page.
299 By default, the digest authentication scheme is not used unless a
300 program is specified.
302 If you want to use a digest authenticator, set this line to
305 auth_param digest program @DEFAULT_PREFIX@/bin/digest_pw_auth @DEFAULT_PREFIX@/etc/digpass
308 HTTP uses iso-latin-1 as characterset, while some authentication
309 backends such as LDAP expects UTF-8. If this is set to on Squid will
310 translate the HTTP iso-latin-1 charset to UTF-8 before sending the
311 username & password to the helper.
313 "children" numberofchildren [startup=N] [idle=N] [concurrency=N]
314 The maximum number of authenticator processes to spawn (default 5).
315 If you start too few Squid will have to wait for them to
316 process a backlog of H(A1) calculations, slowing it down.
317 When the H(A1) calculations are done via a (slow) network
318 you are likely to need lots of authenticator processes.
320 The startup= and idle= options permit some skew in the exact amount
321 run. A minimum of startup=N will begin during startup and reconfigure.
322 Squid will start more in groups of up to idle=N in an attempt to meet
323 traffic needs and to keep idle=N free above those traffic needs up to
326 The concurrency= option sets the number of concurrent requests the
327 helper can process. The default of 0 is used for helpers who only
328 supports one request at a time. Setting this to a number greater than
329 0 changes the protocol used to include a channel number first on the
330 request/response line, allowing multiple requests to be sent to the
331 same helper in parallell without wating for the response.
332 Must not be set unless it's known the helper supports this.
334 auth_param digest children 20 startup=0 idle=1
337 Specifies the realm name which is to be reported to the
338 client for the digest proxy authentication scheme (part of
339 the text the user will see when prompted their username and
340 password). There is no default.
341 auth_param digest realm Squid proxy-caching web server
343 "nonce_garbage_interval" timeinterval
344 Specifies the interval that nonces that have been issued
345 to client_agent's are checked for validity.
347 "nonce_max_duration" timeinterval
348 Specifies the maximum length of time a given nonce will be
351 "nonce_max_count" number
352 Specifies the maximum number of times a given nonce can be
355 "nonce_strictness" on|off
356 Determines if squid requires strict increment-by-1 behavior
357 for nonce counts, or just incrementing (off - for use when
358 useragents generate nonce counts that occasionally miss 1
359 (ie, 1,2,4,6)). Default off.
361 "check_nonce_count" on|off
362 This directive if set to off can disable the nonce count check
363 completely to work around buggy digest qop implementations in
364 certain mainstream browser versions. Default on to check the
365 nonce count to protect from authentication replay attacks.
367 "post_workaround" on|off
368 This is a workaround to certain buggy browsers who sends
369 an incorrect request digest in POST requests when reusing
370 the same nonce as acquired earlier on a GET request.
372 === NTLM scheme options follow ===
375 Specify the command for the external NTLM authenticator.
376 Such a program reads exchanged NTLMSSP packets with
377 the browser via Squid until authentication is completed.
378 If you use an NTLM authenticator, make sure you have 1 acl
379 of type proxy_auth. By default, the NTLM authenticator_program
382 auth_param ntlm program @DEFAULT_PREFIX@/bin/ntlm_auth
384 "children" numberofchildren [startup=N] [idle=N]
385 The maximum number of authenticator processes to spawn (default 5).
386 If you start too few Squid will have to wait for them to
387 process a backlog of credential verifications, slowing it
388 down. When credential verifications are done via a (slow)
389 network you are likely to need lots of authenticator
392 The startup= and idle= options permit some skew in the exact amount
393 run. A minimum of startup=N will begin during startup and reconfigure.
394 Squid will start more in groups of up to idle=N in an attempt to meet
395 traffic needs and to keep idle=N free above those traffic needs up to
398 auth_param ntlm children 20 startup=0 idle=1
401 If you experience problems with PUT/POST requests when using the
402 Negotiate authentication scheme then you can try setting this to
403 off. This will cause Squid to forcibly close the connection on
404 the initial requests where the browser asks which schemes are
405 supported by the proxy.
407 auth_param ntlm keep_alive on
409 === Options for configuring the NEGOTIATE auth-scheme follow ===
412 Specify the command for the external Negotiate authenticator.
413 This protocol is used in Microsoft Active-Directory enabled setups with
414 the Microsoft Internet Explorer or Mozilla Firefox browsers.
415 Its main purpose is to exchange credentials with the Squid proxy
416 using the Kerberos mechanisms.
417 If you use a Negotiate authenticator, make sure you have at least
418 one acl of type proxy_auth active. By default, the negotiate
419 authenticator_program is not used.
420 The only supported program for this role is the ntlm_auth
421 program distributed as part of Samba, version 4 or later.
423 auth_param negotiate program @DEFAULT_PREFIX@/bin/ntlm_auth --helper-protocol=gss-spnego
425 "children" numberofchildren [startup=N] [idle=N]
426 The maximum number of authenticator processes to spawn (default 5).
427 If you start too few Squid will have to wait for them to
428 process a backlog of credential verifications, slowing it
429 down. When crendential verifications are done via a (slow)
430 network you are likely to need lots of authenticator
433 The startup= and idle= options permit some skew in the exact amount
434 run. A minimum of startup=N will begin during startup and reconfigure.
435 Squid will start more in groups of up to idle=N in an attempt to meet
436 traffic needs and to keep idle=N free above those traffic needs up to
439 auth_param negotiate children 20 startup=0 idle=1
442 If you experience problems with PUT/POST requests when using the
443 Negotiate authentication scheme then you can try setting this to
444 off. This will cause Squid to forcibly close the connection on
445 the initial requests where the browser asks which schemes are
446 supported by the proxy.
448 auth_param negotiate keep_alive on
453 #Recommended minimum configuration per scheme:
454 #auth_param negotiate program <uncomment and complete this line to activate>
455 #auth_param negotiate children 20 startup=0 idle=1
456 #auth_param negotiate keep_alive on
458 #auth_param ntlm program <uncomment and complete this line to activate>
459 #auth_param ntlm children 20 startup=0 idle=1
460 #auth_param ntlm keep_alive on
462 #auth_param digest program <uncomment and complete this line>
463 #auth_param digest children 20 startup=0 idle=1
464 #auth_param digest realm Squid proxy-caching web server
465 #auth_param digest nonce_garbage_interval 5 minutes
466 #auth_param digest nonce_max_duration 30 minutes
467 #auth_param digest nonce_max_count 50
469 #auth_param basic program <uncomment and complete this line>
470 #auth_param basic children 5 startup=5 idle=1
471 #auth_param basic realm Squid proxy-caching web server
472 #auth_param basic credentialsttl 2 hours
475 NAME: authenticate_cache_garbage_interval
478 LOC: Config.authenticateGCInterval
480 The time period between garbage collection across the username cache.
481 This is a tradeoff between memory utilization (long intervals - say
482 2 days) and CPU (short intervals - say 1 minute). Only change if you
486 NAME: authenticate_ttl
489 LOC: Config.authenticateTTL
491 The time a user & their credentials stay in the logged in
492 user cache since their last request. When the garbage
493 interval passes, all user credentials that have passed their
494 TTL are removed from memory.
497 NAME: authenticate_ip_ttl
499 LOC: Config.authenticateIpTTL
502 If you use proxy authentication and the 'max_user_ip' ACL,
503 this directive controls how long Squid remembers the IP
504 addresses associated with each user. Use a small value
505 (e.g., 60 seconds) if your users might change addresses
506 quickly, as is the case with dialups. You might be safe
507 using a larger value (e.g., 2 hours) in a corporate LAN
508 environment with relatively static address assignments.
513 -----------------------------------------------------------------------------
516 NAME: external_acl_type
517 TYPE: externalAclHelper
518 LOC: Config.externalAclHelperList
521 This option defines external acl classes using a helper program
522 to look up the status
524 external_acl_type name [options] FORMAT.. /path/to/helper [helper arguments..]
528 ttl=n TTL in seconds for cached results (defaults to 3600
531 TTL for cached negative lookups (default same
534 Maximum number of acl helper processes spawned to service
535 external acl lookups of this type. (default 20)
537 Minimum number of acl helper processes to spawn during
538 startup and reconfigure to service external acl lookups
539 of this type. (default 0)
541 Number of acl helper processes to keep ahead of traffic
542 loads. Squid will spawn this many at once whenever load
543 rises above the capabilities of existing processes.
544 Up to the value of children-max. (default 1)
545 concurrency=n concurrency level per process. Only used with helpers
546 capable of processing more than one query at a time.
547 cache=n limit the result cache size, default is unbounded.
548 grace=n Percentage remaining of TTL where a refresh of a
549 cached entry should be initiated without needing to
550 wait for a new reply. (default is for no grace period)
551 protocol=2.5 Compatibility mode for Squid-2.5 external acl helpers
552 ipv4 / ipv6 IP-mode used to communicate to this helper.
553 For compatability with older configurations and helpers
554 the default is currently 'ipv4'.
556 FORMAT specifications
558 %LOGIN Authenticated user login name
559 %EXT_USER Username from previous external acl
560 %EXT_LOG Log details from previous external acl
561 %EXT_TAG Tag from previous external acl
562 %IDENT Ident user name
564 %SRCPORT Client source port
567 %PROTO Requested protocol
569 %PATH Requested URL path
570 %METHOD Request method
571 %MYADDR Squid interface address
572 %MYPORT Squid http_port number
573 %PATH Requested URL-path (including query-string if any)
574 %USER_CERT SSL User certificate in PEM format
575 %USER_CERTCHAIN SSL User certificate chain in PEM format
576 %USER_CERT_xx SSL User certificate subject attribute xx
577 %USER_CA_xx SSL User certificate issuer attribute xx
579 %>{Header} HTTP request header "Header"
581 HTTP request header "Hdr" list member "member"
583 HTTP request header list member using ; as
584 list separator. ; can be any non-alphanumeric
587 %<{Header} HTTP reply header "Header"
589 HTTP reply header "Hdr" list member "member"
591 HTTP reply header list member using ; as
592 list separator. ; can be any non-alphanumeric
595 In addition to the above, any string specified in the referencing
596 acl will also be included in the helper request line, after the
597 specified formats (see the "acl external" directive)
599 The helper receives lines per the above format specification,
600 and returns lines starting with OK or ERR indicating the validity
601 of the request and optionally followed by additional keywords with
604 General result syntax:
606 OK/ERR keyword=value ...
610 user= The users name (login)
611 password= The users password (for login= cache_peer option)
612 message= Message describing the reason. Available as %o
614 tag= Apply a tag to a request (for both ERR and OK results)
615 Only sets a tag, does not alter existing tags.
616 log= String to be logged in access.log. Available as
617 %ea in logformat specifications
619 If protocol=3.0 (the default) then URL escaping is used to protect
620 each value in both requests and responses.
622 If using protocol=2.5 then all values need to be enclosed in quotes
623 if they may contain whitespace, or the whitespace escaped using \.
624 And quotes or \ characters within the keyword value must be \ escaped.
626 When using the concurrency= option the protocol is changed by
627 introducing a query channel tag infront of the request/response.
628 The query channel tag is a number between 0 and concurrency-1.
635 DEFAULT: manager url_regex -i ^cache_object:// +i ^https?://[^/]+/squid-internal-mgr/
636 DEFAULT: localhost src 127.0.0.1/32 ::1
637 DEFAULT: to_localhost dst 127.0.0.0/8 0.0.0.0/32 ::1
638 DEFAULT_DOC: ACLs all, manager, localhost, and to_localhost are predefined.
640 Defining an Access List
642 Every access list definition must begin with an aclname and acltype,
643 followed by either type-specific arguments or a quoted filename that
646 acl aclname acltype argument ...
647 acl aclname acltype "file" ...
649 When using "file", the file should contain one item per line.
651 By default, regular expressions are CASE-SENSITIVE.
652 To make them case-insensitive, use the -i option. To return case-sensitive
653 use the +i option between patterns, or make a new ACL line without -i.
655 Some acl types require suspending the current request in order
656 to access some external data source.
657 Those which do are marked with the tag [slow], those which
658 don't are marked as [fast].
659 See http://wiki.squid-cache.org/SquidFaq/SquidAcl
660 for further information
662 ***** ACL TYPES AVAILABLE *****
664 acl aclname src ip-address/mask ... # clients IP address [fast]
665 acl aclname src addr1-addr2/mask ... # range of addresses [fast]
666 acl aclname dst ip-address/mask ... # URL host's IP address [slow]
667 acl aclname localip ip-address/mask ... # IP address the client connected to [fast]
669 acl aclname arp mac-address ... (xx:xx:xx:xx:xx:xx notation)
670 # The arp ACL requires the special configure option --enable-arp-acl.
671 # Furthermore, the ARP ACL code is not portable to all operating systems.
672 # It works on Linux, Solaris, Windows, FreeBSD, and some
673 # other *BSD variants.
676 # NOTE: Squid can only determine the MAC address for clients that are on
677 # the same subnet. If the client is on a different subnet,
678 # then Squid cannot find out its MAC address.
680 acl aclname srcdomain .foo.com ...
681 # reverse lookup, from client IP [slow]
682 acl aclname dstdomain .foo.com ...
683 # Destination server from URL [fast]
684 acl aclname srcdom_regex [-i] \.foo\.com ...
685 # regex matching client name [slow]
686 acl aclname dstdom_regex [-i] \.foo\.com ...
687 # regex matching server [fast]
689 # For dstdomain and dstdom_regex a reverse lookup is tried if a IP
690 # based URL is used and no match is found. The name "none" is used
691 # if the reverse lookup fails.
693 acl aclname src_as number ...
694 acl aclname dst_as number ...
696 # Except for access control, AS numbers can be used for
697 # routing of requests to specific caches. Here's an
698 # example for routing all requests for AS#1241 and only
699 # those to mycache.mydomain.net:
700 # acl asexample dst_as 1241
701 # cache_peer_access mycache.mydomain.net allow asexample
702 # cache_peer_access mycache_mydomain.net deny all
704 acl aclname peername myPeer ...
706 # match against a named cache_peer entry
707 # set unique name= on cache_peer lines for reliable use.
709 acl aclname time [day-abbrevs] [h1:m1-h2:m2]
719 # h1:m1 must be less than h2:m2
721 acl aclname url_regex [-i] ^http:// ...
722 # regex matching on whole URL [fast]
723 acl aclname urlpath_regex [-i] \.gif$ ...
724 # regex matching on URL path [fast]
726 acl aclname port 80 70 21 0-1024... # destination TCP port [fast]
728 acl aclname localport 3128 ... # TCP port the client connected to [fast]
729 # NP: for interception mode this is usually '80'
731 acl aclname myportname 3128 ... # http(s)_port name [fast]
733 acl aclname proto HTTP FTP ... # request protocol [fast]
735 acl aclname method GET POST ... # HTTP request method [fast]
737 acl aclname http_status 200 301 500- 400-403 ...
738 # status code in reply [fast]
740 acl aclname browser [-i] regexp ...
741 # pattern match on User-Agent header (see also req_header below) [fast]
743 acl aclname referer_regex [-i] regexp ...
744 # pattern match on Referer header [fast]
745 # Referer is highly unreliable, so use with care
747 acl aclname ident username ...
748 acl aclname ident_regex [-i] pattern ...
749 # string match on ident output [slow]
750 # use REQUIRED to accept any non-null ident.
752 acl aclname proxy_auth [-i] username ...
753 acl aclname proxy_auth_regex [-i] pattern ...
754 # perform http authentication challenge to the client and match against
755 # supplied credentials [slow]
757 # takes a list of allowed usernames.
758 # use REQUIRED to accept any valid username.
760 # Will use proxy authentication in forward-proxy scenarios, and plain
761 # http authenticaiton in reverse-proxy scenarios
763 # NOTE: when a Proxy-Authentication header is sent but it is not
764 # needed during ACL checking the username is NOT logged
767 # NOTE: proxy_auth requires a EXTERNAL authentication program
768 # to check username/password combinations (see
769 # auth_param directive).
771 # NOTE: proxy_auth can't be used in a transparent/intercepting proxy
772 # as the browser needs to be configured for using a proxy in order
773 # to respond to proxy authentication.
775 acl aclname snmp_community string ...
776 # A community string to limit access to your SNMP Agent [fast]
779 # acl snmppublic snmp_community public
781 acl aclname maxconn number
782 # This will be matched when the client's IP address has
783 # more than <number> TCP connections established. [fast]
784 # NOTE: This only measures direct TCP links so X-Forwarded-For
785 # indirect clients are not counted.
787 acl aclname max_user_ip [-s] number
788 # This will be matched when the user attempts to log in from more
789 # than <number> different ip addresses. The authenticate_ip_ttl
790 # parameter controls the timeout on the ip entries. [fast]
791 # If -s is specified the limit is strict, denying browsing
792 # from any further IP addresses until the ttl has expired. Without
793 # -s Squid will just annoy the user by "randomly" denying requests.
794 # (the counter is reset each time the limit is reached and a
796 # NOTE: in acceleration mode or where there is mesh of child proxies,
797 # clients may appear to come from multiple addresses if they are
798 # going through proxy farms, so a limit of 1 may cause user problems.
800 acl aclname random probability
801 # Pseudo-randomly match requests. Based on the probability given.
802 # Probability may be written as a decimal (0.333), fraction (1/3)
803 # or ratio of matches:non-matches (3:5).
805 acl aclname req_mime_type [-i] mime-type ...
806 # regex match against the mime type of the request generated
807 # by the client. Can be used to detect file upload or some
808 # types HTTP tunneling requests [fast]
809 # NOTE: This does NOT match the reply. You cannot use this
810 # to match the returned file type.
812 acl aclname req_header header-name [-i] any\.regex\.here
813 # regex match against any of the known request headers. May be
814 # thought of as a superset of "browser", "referer" and "mime-type"
817 acl aclname rep_mime_type [-i] mime-type ...
818 # regex match against the mime type of the reply received by
819 # squid. Can be used to detect file download or some
820 # types HTTP tunneling requests. [fast]
821 # NOTE: This has no effect in http_access rules. It only has
822 # effect in rules that affect the reply data stream such as
825 acl aclname rep_header header-name [-i] any\.regex\.here
826 # regex match against any of the known reply headers. May be
827 # thought of as a superset of "browser", "referer" and "mime-type"
830 acl aclname external class_name [arguments...]
831 # external ACL lookup via a helper class defined by the
832 # external_acl_type directive [slow]
834 acl aclname user_cert attribute values...
835 # match against attributes in a user SSL certificate
836 # attribute is one of DN/C/O/CN/L/ST [fast]
838 acl aclname ca_cert attribute values...
839 # match against attributes a users issuing CA SSL certificate
840 # attribute is one of DN/C/O/CN/L/ST [fast]
842 acl aclname ext_user username ...
843 acl aclname ext_user_regex [-i] pattern ...
844 # string match on username returned by external acl helper [slow]
845 # use REQUIRED to accept any non-null user name.
847 acl aclname tag tagvalue ...
848 # string match on tag returned by external acl helper [slow]
850 acl aclname hier_code codename ...
851 # string match against squid hierarchy code(s); [fast]
852 # e.g., DIRECT, PARENT_HIT, NONE, etc.
854 # NOTE: This has no effect in http_access rules. It only has
855 # effect in rules that affect the reply data stream such as
859 acl macaddress arp 09:00:2b:23:45:67
860 acl myexample dst_as 1241
861 acl password proxy_auth REQUIRED
862 acl fileupload req_mime_type -i ^multipart/form-data$
863 acl javascript rep_mime_type -i ^application/x-javascript$
867 # Recommended minimum configuration:
870 # Example rule allowing access from your local networks.
871 # Adapt to list your (internal) IP networks from where browsing
873 acl localnet src 10.0.0.0/8 # RFC1918 possible internal network
874 acl localnet src 172.16.0.0/12 # RFC1918 possible internal network
875 acl localnet src 192.168.0.0/16 # RFC1918 possible internal network
876 acl localnet src fc00::/7 # RFC 4193 local private network range
877 acl localnet src fe80::/10 # RFC 4291 link-local (directly plugged) machines
879 acl SSL_ports port 443
880 acl Safe_ports port 80 # http
881 acl Safe_ports port 21 # ftp
882 acl Safe_ports port 443 # https
883 acl Safe_ports port 70 # gopher
884 acl Safe_ports port 210 # wais
885 acl Safe_ports port 1025-65535 # unregistered ports
886 acl Safe_ports port 280 # http-mgmt
887 acl Safe_ports port 488 # gss-http
888 acl Safe_ports port 591 # filemaker
889 acl Safe_ports port 777 # multiling http
890 acl CONNECT method CONNECT
894 NAME: follow_x_forwarded_for
896 IFDEF: FOLLOW_X_FORWARDED_FOR
897 LOC: Config.accessList.followXFF
898 DEFAULT_IF_NONE: deny all
900 Allowing or Denying the X-Forwarded-For header to be followed to
901 find the original source of a request.
903 Requests may pass through a chain of several other proxies
904 before reaching us. The X-Forwarded-For header will contain a
905 comma-separated list of the IP addresses in the chain, with the
906 rightmost address being the most recent.
908 If a request reaches us from a source that is allowed by this
909 configuration item, then we consult the X-Forwarded-For header
910 to see where that host received the request from. If the
911 X-Forwarded-For header contains multiple addresses, we continue
912 backtracking until we reach an address for which we are not allowed
913 to follow the X-Forwarded-For header, or until we reach the first
914 address in the list. For the purpose of ACL used in the
915 follow_x_forwarded_for directive the src ACL type always matches
916 the address we are testing and srcdomain matches its rDNS.
918 The end result of this process is an IP address that we will
919 refer to as the indirect client address. This address may
920 be treated as the client address for access control, ICAP, delay
921 pools and logging, depending on the acl_uses_indirect_client,
922 icap_uses_indirect_client, delay_pool_uses_indirect_client,
923 log_uses_indirect_client and tproxy_uses_indirect_client options.
925 This clause only supports fast acl types.
926 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
928 SECURITY CONSIDERATIONS:
930 Any host for which we follow the X-Forwarded-For header
931 can place incorrect information in the header, and Squid
932 will use the incorrect information as if it were the
933 source address of the request. This may enable remote
934 hosts to bypass any access control restrictions that are
935 based on the client's source addresses.
939 acl localhost src 127.0.0.1
940 acl my_other_proxy srcdomain .proxy.example.com
941 follow_x_forwarded_for allow localhost
942 follow_x_forwarded_for allow my_other_proxy
945 NAME: acl_uses_indirect_client
948 IFDEF: FOLLOW_X_FORWARDED_FOR
950 LOC: Config.onoff.acl_uses_indirect_client
952 Controls whether the indirect client address
953 (see follow_x_forwarded_for) is used instead of the
954 direct client address in acl matching.
956 NOTE: maxconn ACL considers direct TCP links and indirect
957 clients will always have zero. So no match.
960 NAME: delay_pool_uses_indirect_client
963 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_DELAY_POOLS
965 LOC: Config.onoff.delay_pool_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 delay pools.
972 NAME: log_uses_indirect_client
975 IFDEF: FOLLOW_X_FORWARDED_FOR
977 LOC: Config.onoff.log_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 in the access log.
984 NAME: tproxy_uses_indirect_client
987 IFDEF: FOLLOW_X_FORWARDED_FOR&&LINUX_NETFILTER
989 LOC: Config.onoff.tproxy_uses_indirect_client
991 Controls whether the indirect client address
992 (see follow_x_forwarded_for) is used instead of the
993 direct client address when spoofing the outgoing client.
995 This has no effect on requests arriving in non-tproxy
998 SECURITY WARNING: Usage of this option is dangerous
999 and should not be used trivially. Correct configuration
1000 of folow_x_forewarded_for with a limited set of trusted
1001 sources is required to prevent abuse of your proxy.
1006 LOC: Config.accessList.http
1007 DEFAULT_IF_NONE: deny all
1009 Allowing or Denying access based on defined access lists
1011 Access to the HTTP port:
1012 http_access allow|deny [!]aclname ...
1014 NOTE on default values:
1016 If there are no "access" lines present, the default is to deny
1019 If none of the "access" lines cause a match, the default is the
1020 opposite of the last line in the list. If the last line was
1021 deny, the default is allow. Conversely, if the last line
1022 is allow, the default will be deny. For these reasons, it is a
1023 good idea to have an "deny all" entry at the end of your access
1024 lists to avoid potential confusion.
1026 This clause supports both fast and slow acl types.
1027 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1032 # Recommended minimum Access Permission configuration:
1034 # Only allow cachemgr access from localhost
1035 http_access allow localhost manager
1036 http_access deny manager
1038 # Deny requests to certain unsafe ports
1039 http_access deny !Safe_ports
1041 # Deny CONNECT to other than secure SSL ports
1042 http_access deny CONNECT !SSL_ports
1044 # We strongly recommend the following be uncommented to protect innocent
1045 # web applications running on the proxy server who think the only
1046 # one who can access services on "localhost" is a local user
1047 #http_access deny to_localhost
1050 # INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS
1053 # Example rule allowing access from your local networks.
1054 # Adapt localnet in the ACL section to list your (internal) IP networks
1055 # from where browsing should be allowed
1056 http_access allow localnet
1057 http_access allow localhost
1059 # And finally deny all other access to this proxy
1060 http_access deny all
1064 NAME: adapted_http_access http_access2
1066 LOC: Config.accessList.adapted_http
1069 Allowing or Denying access based on defined access lists
1071 Essentially identical to http_access, but runs after redirectors
1072 and ICAP/eCAP adaptation. Allowing access control based on their
1075 If not set then only http_access is used.
1078 NAME: http_reply_access
1080 LOC: Config.accessList.reply
1083 Allow replies to client requests. This is complementary to http_access.
1085 http_reply_access allow|deny [!] aclname ...
1087 NOTE: if there are no access lines present, the default is to allow
1090 If none of the access lines cause a match the opposite of the
1091 last line will apply. Thus it is good practice to end the rules
1092 with an "allow all" or "deny all" entry.
1094 This clause supports both fast and slow acl types.
1095 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1100 LOC: Config.accessList.icp
1101 DEFAULT_IF_NONE: deny all
1103 Allowing or Denying access to the ICP port based on defined
1106 icp_access allow|deny [!]aclname ...
1108 See http_access for details
1110 This clause only supports fast acl types.
1111 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1113 # Allow ICP queries from local networks only
1114 #icp_access allow localnet
1115 #icp_access deny all
1121 LOC: Config.accessList.htcp
1122 DEFAULT_IF_NONE: deny all
1124 Allowing or Denying access to the HTCP port based on defined
1127 htcp_access allow|deny [!]aclname ...
1129 See http_access for details
1131 NOTE: The default if no htcp_access lines are present is to
1132 deny all traffic. This default may cause problems with peers
1133 using the htcp option.
1135 This clause only supports fast acl types.
1136 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1138 # Allow HTCP queries from local networks only
1139 #htcp_access allow localnet
1140 #htcp_access deny all
1143 NAME: htcp_clr_access
1146 LOC: Config.accessList.htcp_clr
1147 DEFAULT_IF_NONE: deny all
1149 Allowing or Denying access to purge content using HTCP based
1150 on defined access lists
1152 htcp_clr_access allow|deny [!]aclname ...
1154 See http_access for details
1156 This clause only supports fast acl types.
1157 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1159 # Allow HTCP CLR requests from trusted peers
1160 acl htcp_clr_peer src 172.16.1.2
1161 htcp_clr_access allow htcp_clr_peer
1166 LOC: Config.accessList.miss
1169 Determins whether network access is permitted when satisfying a request.
1172 to force your neighbors to use you as a sibling instead of
1175 acl localclients src 172.16.0.0/16
1176 miss_access allow localclients
1177 miss_access deny !localclients
1179 This means only your local clients are allowed to fetch relayed/MISS
1180 replies from the network and all other clients can only fetch cached
1184 The default for this setting allows all clients who passed the
1185 http_access rules to relay via this proxy.
1187 This clause only supports fast acl types.
1188 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1191 NAME: ident_lookup_access
1194 DEFAULT_IF_NONE: deny all
1195 LOC: Ident::TheConfig.identLookup
1197 A list of ACL elements which, if matched, cause an ident
1198 (RFC 931) lookup to be performed for this request. For
1199 example, you might choose to always perform ident lookups
1200 for your main multi-user Unix boxes, but not for your Macs
1201 and PCs. By default, ident lookups are not performed for
1204 To enable ident lookups for specific client addresses, you
1205 can follow this example:
1207 acl ident_aware_hosts src 198.168.1.0/24
1208 ident_lookup_access allow ident_aware_hosts
1209 ident_lookup_access deny all
1211 Only src type ACL checks are fully supported. A srcdomain
1212 ACL might work at times, but it will not always provide
1215 This clause only supports fast acl types.
1216 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1219 NAME: reply_body_max_size
1220 COMMENT: size [acl acl...]
1223 LOC: Config.ReplyBodySize
1225 This option specifies the maximum size of a reply body. It can be
1226 used to prevent users from downloading very large files, such as
1227 MP3's and movies. When the reply headers are received, the
1228 reply_body_max_size lines are processed, and the first line where
1229 all (if any) listed ACLs are true is used as the maximum body size
1232 This size is checked twice. First when we get the reply headers,
1233 we check the content-length value. If the content length value exists
1234 and is larger than the allowed size, the request is denied and the
1235 user receives an error message that says "the request or reply
1236 is too large." If there is no content-length, and the reply
1237 size exceeds this limit, the client's connection is just closed
1238 and they will receive a partial reply.
1240 WARNING: downstream caches probably can not detect a partial reply
1241 if there is no content-length header, so they will cache
1242 partial responses and give them out as hits. You should NOT
1243 use this option if you have downstream caches.
1245 WARNING: A maximum size smaller than the size of squid's error messages
1246 will cause an infinite loop and crash squid. Ensure that the smallest
1247 non-zero value you use is greater that the maximum header size plus
1248 the size of your largest error page.
1250 If you set this parameter none (the default), there will be
1253 Configuration Format is:
1254 reply_body_max_size SIZE UNITS [acl ...]
1256 reply_body_max_size 10 MB
1262 -----------------------------------------------------------------------------
1265 NAME: http_port ascii_port
1266 TYPE: http_port_list
1268 LOC: Config.Sockaddr.http
1270 Usage: port [mode] [options]
1271 hostname:port [mode] [options]
1272 1.2.3.4:port [mode] [options]
1274 The socket addresses where Squid will listen for HTTP client
1275 requests. You may specify multiple socket addresses.
1276 There are three forms: port alone, hostname with port, and
1277 IP address with port. If you specify a hostname or IP
1278 address, Squid binds the socket to that specific
1279 address. Most likely, you do not need to bind to a specific
1280 address, so you can use the port number alone.
1282 If you are running Squid in accelerator mode, you
1283 probably want to listen on port 80 also, or instead.
1285 The -a command line option may be used to specify additional
1286 port(s) where Squid listens for proxy request. Such ports will
1287 be plain proxy ports with no options.
1289 You may specify multiple socket addresses on multiple lines.
1293 intercept Support for IP-Layer interception of
1294 outgoing requests without browser settings.
1295 NP: disables authentication and IPv6 on the port.
1297 tproxy Support Linux TPROXY for spoofing outgoing
1298 connections using the client IP address.
1299 NP: disables authentication and maybe IPv6 on the port.
1301 accel Accelerator / reverse proxy mode
1303 ssl-bump Intercept each CONNECT request matching ssl_bump ACL,
1304 establish secure connection with the client and with
1305 the server, decrypt HTTP messages as they pass through
1306 Squid, and treat them as unencrypted HTTP messages,
1307 becoming the man-in-the-middle.
1309 The ssl_bump option is required to fully enable
1310 the SslBump feature.
1312 Omitting the mode flag causes default forward proxy mode to be used.
1315 Accelerator Mode Options:
1317 defaultsite=domainname
1318 What to use for the Host: header if it is not present
1319 in a request. Determines what site (not origin server)
1320 accelerators should consider the default.
1322 no-vhost Disable using HTTP/1.1 Host header for virtual domain support.
1324 protocol= Protocol to reconstruct accelerated requests with.
1325 Defaults to http for http_port and https for
1328 vport Virtual host port support. Using the http_port number
1329 instead of the port passed on Host: headers.
1331 vport=NN Virtual host port support. Using the specified port
1332 number instead of the port passed on Host: headers.
1335 Act as if this Squid is the origin server.
1336 This currently means generate new Date: and Expires:
1337 headers on HIT instead of adding Age:.
1339 ignore-cc Ignore request Cache-Control headers.
1341 WARNING: This option violates HTTP specifications if
1342 used in non-accelerator setups.
1344 allow-direct Allow direct forwarding in accelerator mode. Normally
1345 accelerated requests are denied direct forwarding as if
1346 never_direct was used.
1348 WARNING: this option opens accelerator mode to security
1349 vulnerabilities usually only affecting in interception
1350 mode. Make sure to protect forwarding with suitable
1351 http_access rules when using this.
1354 SSL Bump Mode Options:
1356 cert= Path to SSL certificate (PEM format).
1358 key= Path to SSL private key file (PEM format)
1359 if not specified, the certificate file is
1360 assumed to be a combined certificate and
1363 version= The version of SSL/TLS supported
1364 1 automatic (default)
1369 cipher= Colon separated list of supported ciphers.
1371 options= Various SSL engine options. The most important
1373 NO_SSLv2 Disallow the use of SSLv2
1374 NO_SSLv3 Disallow the use of SSLv3
1375 NO_TLSv1 Disallow the use of TLSv1
1376 SINGLE_DH_USE Always create a new key when using
1377 temporary/ephemeral DH key exchanges
1378 See src/ssl_support.c or OpenSSL SSL_CTX_set_options
1379 documentation for a complete list of options.
1381 clientca= File containing the list of CAs to use when
1382 requesting a client certificate.
1384 cafile= File containing additional CA certificates to
1385 use when verifying client certificates. If unset
1386 clientca will be used.
1388 capath= Directory containing additional CA certificates
1389 and CRL lists to use when verifying client certificates.
1391 crlfile= File of additional CRL lists to use when verifying
1392 the client certificate, in addition to CRLs stored in
1393 the capath. Implies VERIFY_CRL flag below.
1395 dhparams= File containing DH parameters for temporary/ephemeral
1398 sslflags= Various flags modifying the use of SSL:
1400 Don't request client certificates
1401 immediately, but wait until acl processing
1402 requires a certificate (not yet implemented).
1404 Don't use the default CA lists built in
1407 Don't allow for session reuse. Each connection
1408 will result in a new SSL session.
1410 Verify CRL lists when accepting client
1413 Verify CRL lists for all certificates in the
1414 client certificate chain.
1416 sslcontext= SSL session ID context identifier.
1418 generate-host-certificates[=<on|off>]
1419 Dynamically create SSL server certificates for the
1420 destination hosts of bumped CONNECT requests.When
1421 enabled, the cert and key options are used to sign
1422 generated certificates. Otherwise generated
1423 certificate will be selfsigned.
1424 If there is CA certificate life time of generated
1425 certificate equals lifetime of CA certificate. If
1426 generated certificate is selfsigned lifetime is three
1428 This option is enabled by default when SslBump is used.
1429 See the sslBump option above for more information.
1431 dynamic_cert_mem_cache_size=SIZE
1432 Approximate total RAM size spent on cached generated
1433 certificates. If set to zero, caching is disabled. The
1434 default value is 4MB. An average XXX-bit certificate
1435 consumes about XXX bytes of RAM.
1439 connection-auth[=on|off]
1440 use connection-auth=off to tell Squid to prevent
1441 forwarding Microsoft connection oriented authentication
1442 (NTLM, Negotiate and Kerberos)
1444 disable-pmtu-discovery=
1445 Control Path-MTU discovery usage:
1446 off lets OS decide on what to do (default).
1447 transparent disable PMTU discovery when transparent
1449 always disable always PMTU discovery.
1451 In many setups of transparently intercepting proxies
1452 Path-MTU discovery can not work on traffic towards the
1453 clients. This is the case when the intercepting device
1454 does not fully track connections and fails to forward
1455 ICMP must fragment messages to the cache server. If you
1456 have such setup and experience that certain clients
1457 sporadically hang or never complete requests set
1458 disable-pmtu-discovery option to 'transparent'.
1460 name= Specifies a internal name for the port. Defaults to
1461 the port specification (port or addr:port)
1463 tcpkeepalive[=idle,interval,timeout]
1464 Enable TCP keepalive probes of idle connections.
1465 In seconds; idle is the initial time before TCP starts
1466 probing the connection, interval how often to probe, and
1467 timeout the time before giving up.
1469 If you run Squid on a dual-homed machine with an internal
1470 and an external interface we recommend you to specify the
1471 internal address:port in http_port. This way Squid will only be
1472 visible on the internal address.
1476 # Squid normally listens to port 3128
1477 http_port @DEFAULT_HTTP_PORT@
1483 TYPE: https_port_list
1485 LOC: Config.Sockaddr.https
1487 Usage: [ip:]port cert=certificate.pem [key=key.pem] [mode] [options...]
1489 The socket address where Squid will listen for HTTPS client
1492 This is really only useful for situations where you are running
1493 squid in accelerator mode and you want to do the SSL work at the
1496 You may specify multiple socket addresses on multiple lines,
1497 each with their own SSL certificate and/or options.
1501 accel Accelerator / reverse proxy mode
1503 Omitting the mode flag causes default forward proxy mode to be used.
1506 See http_port for a list of generic options
1511 cert= Path to SSL certificate (PEM format).
1513 key= Path to SSL private key file (PEM format)
1514 if not specified, the certificate file is
1515 assumed to be a combined certificate and
1518 version= The version of SSL/TLS supported
1519 1 automatic (default)
1524 cipher= Colon separated list of supported ciphers.
1526 options= Various SSL engine options. The most important
1528 NO_SSLv2 Disallow the use of SSLv2
1529 NO_SSLv3 Disallow the use of SSLv3
1530 NO_TLSv1 Disallow the use of TLSv1
1531 SINGLE_DH_USE Always create a new key when using
1532 temporary/ephemeral DH key exchanges
1533 See src/ssl_support.c or OpenSSL SSL_CTX_set_options
1534 documentation for a complete list of options.
1536 clientca= File containing the list of CAs to use when
1537 requesting a client certificate.
1539 cafile= File containing additional CA certificates to
1540 use when verifying client certificates. If unset
1541 clientca will be used.
1543 capath= Directory containing additional CA certificates
1544 and CRL lists to use when verifying client certificates.
1546 crlfile= File of additional CRL lists to use when verifying
1547 the client certificate, in addition to CRLs stored in
1548 the capath. Implies VERIFY_CRL flag below.
1550 dhparams= File containing DH parameters for temporary/ephemeral
1553 sslflags= Various flags modifying the use of SSL:
1555 Don't request client certificates
1556 immediately, but wait until acl processing
1557 requires a certificate (not yet implemented).
1559 Don't use the default CA lists built in
1562 Don't allow for session reuse. Each connection
1563 will result in a new SSL session.
1565 Verify CRL lists when accepting client
1568 Verify CRL lists for all certificates in the
1569 client certificate chain.
1571 sslcontext= SSL session ID context identifier.
1575 NAME: tcp_outgoing_tos tcp_outgoing_ds tcp_outgoing_dscp
1578 LOC: Ip::Qos::TheConfig.tosToServer
1580 Allows you to select a TOS/Diffserv value for packets outgoing
1581 on the server side, based on an ACL.
1583 tcp_outgoing_tos ds-field [!]aclname ...
1585 Example where normal_service_net uses the TOS value 0x00
1586 and good_service_net uses 0x20
1588 acl normal_service_net src 10.0.0.0/24
1589 acl good_service_net src 10.0.1.0/24
1590 tcp_outgoing_tos 0x00 normal_service_net
1591 tcp_outgoing_tos 0x20 good_service_net
1593 TOS/DSCP values really only have local significance - so you should
1594 know what you're specifying. For more information, see RFC2474,
1595 RFC2475, and RFC3260.
1597 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
1598 "default" to use whatever default your host has. Note that in
1599 practice often only multiples of 4 is usable as the two rightmost bits
1600 have been redefined for use by ECN (RFC 3168 section 23.1).
1602 Processing proceeds in the order specified, and stops at first fully
1606 NAME: clientside_tos
1609 LOC: Ip::Qos::TheConfig.tosToClient
1611 Allows you to select a TOS/Diffserv value for packets being transmitted
1612 on the client-side, based on an ACL.
1614 clientside_tos ds-field [!]aclname ...
1616 Example where normal_service_net uses the TOS value 0x00
1617 and good_service_net uses 0x20
1619 acl normal_service_net src 10.0.0.0/24
1620 acl good_service_net src 10.0.1.0/24
1621 clientside_tos 0x00 normal_service_net
1622 clientside_tos 0x20 good_service_net
1624 Note: This feature is incompatible with qos_flows. Any TOS values set here
1625 will be overwritten by TOS values in qos_flows.
1628 NAME: tcp_outgoing_mark
1630 IFDEF: SO_MARK&&USE_LIBCAP
1632 LOC: Ip::Qos::TheConfig.nfmarkToServer
1634 Allows you to apply a Netfilter mark value to outgoing packets
1635 on the server side, based on an ACL.
1637 tcp_outgoing_mark mark-value [!]aclname ...
1639 Example where normal_service_net uses the mark value 0x00
1640 and good_service_net uses 0x20
1642 acl normal_service_net src 10.0.0.0/24
1643 acl good_service_net src 10.0.1.0/24
1644 tcp_outgoing_mark 0x00 normal_service_net
1645 tcp_outgoing_mark 0x20 good_service_net
1648 NAME: clientside_mark
1650 IFDEF: SO_MARK&&USE_LIBCAP
1652 LOC: Ip::Qos::TheConfig.nfmarkToClient
1654 Allows you to apply a Netfilter mark value to packets being transmitted
1655 on the client-side, based on an ACL.
1657 clientside_mark mark-value [!]aclname ...
1659 Example where normal_service_net uses the mark value 0x00
1660 and good_service_net uses 0x20
1662 acl normal_service_net src 10.0.0.0/24
1663 acl good_service_net src 10.0.1.0/24
1664 clientside_mark 0x00 normal_service_net
1665 clientside_mark 0x20 good_service_net
1667 Note: This feature is incompatible with qos_flows. Any mark values set here
1668 will be overwritten by mark values in qos_flows.
1675 LOC: Ip::Qos::TheConfig
1677 Allows you to select a TOS/DSCP value to mark outgoing
1678 connections with, based on where the reply was sourced. For
1679 platforms using netfilter, allows you to set a netfilter mark
1680 value instead of, or in addition to, a TOS value.
1682 TOS values really only have local significance - so you should
1683 know what you're specifying. For more information, see RFC2474,
1684 RFC2475, and RFC3260.
1686 The TOS/DSCP byte must be exactly that - a octet value 0 - 255. Note that
1687 in practice often only multiples of 4 is usable as the two rightmost bits
1688 have been redefined for use by ECN (RFC 3168 section 23.1).
1690 Mark values can be any unsigned 32-bit integer value.
1692 This setting is configured by setting the following values:
1694 tos|mark Whether to set TOS or netfilter mark values
1696 local-hit=0xFF Value to mark local cache hits.
1698 sibling-hit=0xFF Value to mark hits from sibling peers.
1700 parent-hit=0xFF Value to mark hits from parent peers.
1702 miss=0xFF Value to mark cache misses. Takes precedence
1703 over the preserve-miss feature (see below).
1705 The TOS variant of the following features are only possible on Linux
1706 and require your kernel to be patched with the TOS preserving ZPH
1707 patch, available from http://zph.bratcheda.org
1708 No patch is needed to preserve the netfilter mark, which will work
1709 with all variants of netfilter.
1711 disable-preserve-miss
1712 This option disables the preservation of the TOS or netfilter
1713 mark. By default, the existing TOS or netfilter mark value of
1714 the response coming from the remote server will be retained
1715 and masked with miss-mark.
1716 NOTE: in the case of a netfilter mark, the mark must be set on
1717 the connection (using the CONNMARK target) not on the packet
1721 Allows you to mask certain bits in the TOS or mark value
1722 received from the remote server, before copying the value to
1723 the TOS sent towards clients.
1724 Default for tos: 0xFF (TOS from server is not changed).
1725 Default for mark: 0xFFFFFFFF (mark from server is not changed).
1727 All of these features require the --enable-zph-qos compilation flag
1728 (enabled by default). Netfilter marking also requires the
1729 libnetfilter_conntrack libraries (--with-netfilter-conntrack) and
1730 libcap 2.09+ (--with-libcap).
1734 NAME: tcp_outgoing_address
1737 LOC: Config.accessList.outgoing_address
1739 Allows you to map requests to different outgoing IP addresses
1740 based on the username or source address of the user making
1743 tcp_outgoing_address ipaddr [[!]aclname] ...
1746 Forwarding clients with dedicated IPs for certain subnets.
1748 acl normal_service_net src 10.0.0.0/24
1749 acl good_service_net src 10.0.2.0/24
1751 tcp_outgoing_address 2001:db8::c001 good_service_net
1752 tcp_outgoing_address 10.1.0.2 good_service_net
1754 tcp_outgoing_address 2001:db8::beef normal_service_net
1755 tcp_outgoing_address 10.1.0.1 normal_service_net
1757 tcp_outgoing_address 2001:db8::1
1758 tcp_outgoing_address 10.1.0.3
1760 Processing proceeds in the order specified, and stops at first fully
1763 Squid will add an implicit IP version test to each line.
1764 Requests going to IPv4 websites will use the outgoing 10.1.0.* addresses.
1765 Requests going to IPv6 websites will use the outgoing 2001:db8:* addresses.
1768 NOTE: The use of this directive using client dependent ACLs is
1769 incompatible with the use of server side persistent connections. To
1770 ensure correct results it is best to set server_persistent_connections
1771 to off when using this directive in such configurations.
1773 NOTE: The use of this directive to set a local IP on outgoing TCP links
1774 is incompatible with using TPROXY to set client IP out outbound TCP links.
1775 When needing to contact peers use the no-tproxy cache_peer option and the
1776 client_dst_passthru directive re-enable normal forwarding such as this.
1780 NAME: host_verify_strict
1783 LOC: Config.onoff.hostStrictVerify
1785 Regardless of this option setting, when dealing with intercepted
1786 traffic, Squid always verifies that the destination IP address matches
1787 the Host header domain or IP (called 'authority form URL'). Squid
1788 responds with an HTTP 409 (Conflict) error page and logs a security
1789 warning if there is no match.
1791 When set to ON, Squid verifies that the destination IP address matches
1792 the Host header for forward-proxy and reverse-proxy traffic as well. For
1793 those traffic types, Squid also enables the following checks, comparing
1794 the corresponding Host header and Request-URI components:
1796 * The host names (domain or IP) must be identical,
1797 but valueless or missing Host header disables all checks.
1798 For the two host names to match, both must be either IP or FQDN.
1800 * Port numbers must be identical,
1801 but if a port is missing, the scheme-default port is assumed.
1803 This enforcement is performed to satisfy a MUST-level requirement in
1804 RFC 2616 section 14.23: "The Host field value MUST represent the naming
1805 authority of the origin server or gateway given by the original URL".
1808 NAME: client_dst_passthru
1811 LOC: Config.onoff.client_dst_passthru
1813 With NAT or TPROXY intercepted traffic Squid may pass the request
1814 directly to the original client destination IP or seek a faster
1817 This option (on by default) prevents cache_peer and alternative DNS
1818 entries being used on intercepted traffic. Both of which lead to
1819 the security vulnerability outlined below.
1823 This directive should only be disabled if cache_peer are required.
1825 As described in CVE-2009-0801 when the Host: header alone is used
1826 to determine the destination of a request it becomes trivial for
1827 malicious scripts on remote websites to bypass browser same-origin
1828 security policy and sandboxing protections.
1830 The cause of this is that such applets are allowed to perform their
1831 own HTTP stack, in which case the same-origin policy of the browser
1832 sandbox only verifies that the applet tries to contact the same IP
1833 as from where it was loaded at the IP level. The Host: header may
1834 be different from the connected IP and approved origin.
1840 -----------------------------------------------------------------------------
1843 NAME: ssl_unclean_shutdown
1847 LOC: Config.SSL.unclean_shutdown
1849 Some browsers (especially MSIE) bugs out on SSL shutdown
1856 LOC: Config.SSL.ssl_engine
1859 The OpenSSL engine to use. You will need to set this if you
1860 would like to use hardware SSL acceleration for example.
1863 NAME: sslproxy_client_certificate
1866 LOC: Config.ssl_client.cert
1869 Client SSL Certificate to use when proxying https:// URLs
1872 NAME: sslproxy_client_key
1875 LOC: Config.ssl_client.key
1878 Client SSL Key to use when proxying https:// URLs
1881 NAME: sslproxy_version
1884 LOC: Config.ssl_client.version
1887 SSL version level to use when proxying https:// URLs
1890 NAME: sslproxy_options
1893 LOC: Config.ssl_client.options
1896 SSL engine options to use when proxying https:// URLs
1898 The most important being:
1900 NO_SSLv2 Disallow the use of SSLv2
1901 NO_SSLv3 Disallow the use of SSLv3
1902 NO_TLSv1 Disallow the use of TLSv1
1904 Always create a new key when using
1905 temporary/ephemeral DH key exchanges
1907 These options vary depending on your SSL engine.
1908 See the OpenSSL SSL_CTX_set_options documentation for a
1909 complete list of possible options.
1912 NAME: sslproxy_cipher
1915 LOC: Config.ssl_client.cipher
1918 SSL cipher list to use when proxying https:// URLs
1920 Colon separated list of supported ciphers.
1923 NAME: sslproxy_cafile
1926 LOC: Config.ssl_client.cafile
1929 file containing CA certificates to use when verifying server
1930 certificates while proxying https:// URLs
1933 NAME: sslproxy_capath
1936 LOC: Config.ssl_client.capath
1939 directory containing CA certificates to use when verifying
1940 server certificates while proxying https:// URLs
1946 LOC: Config.accessList.ssl_bump
1949 This ACL controls which CONNECT requests to an http_port
1950 marked with an sslBump flag are actually "bumped". Please
1951 see the sslBump flag of an http_port option for more details
1952 about decoding proxied SSL connections.
1954 By default, no requests are bumped.
1956 See also: http_port ssl-bump
1958 This clause supports both fast and slow acl types.
1959 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1962 # Example: Bump all requests except those originating from localhost and
1963 # those going to webax.com or example.com sites.
1965 acl localhost src 127.0.0.1/32
1966 acl broken_sites dstdomain .webax.com
1967 acl broken_sites dstdomain .example.com
1968 ssl_bump deny localhost
1969 ssl_bump deny broken_sites
1973 NAME: sslproxy_flags
1976 LOC: Config.ssl_client.flags
1979 Various flags modifying the use of SSL while proxying https:// URLs:
1980 DONT_VERIFY_PEER Accept certificates that fail verification.
1981 For refined control, see sslproxy_cert_error.
1982 NO_DEFAULT_CA Don't use the default CA list built in
1986 NAME: sslproxy_cert_error
1989 LOC: Config.ssl_client.cert_error
1992 Use this ACL to bypass server certificate validation errors.
1994 For example, the following lines will bypass all validation errors
1995 when talking to servers located at 172.16.0.0/16. All other
1996 validation errors will result in ERR_SECURE_CONNECT_FAIL error.
1998 acl BrokenServersAtTrustedIP dst 172.16.0.0/16
1999 sslproxy_cert_error allow BrokenServersAtTrustedIP
2000 sslproxy_cert_error deny all
2002 This clause only supports fast acl types.
2003 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2004 Using slow acl types may result in server crashes
2006 Without this option, all server certificate validation errors
2007 terminate the transaction. Bypassing validation errors is dangerous
2008 because an error usually implies that the server cannot be trusted and
2009 the connection may be insecure.
2011 See also: sslproxy_flags and DONT_VERIFY_PEER.
2013 Default setting: sslproxy_cert_error deny all
2016 NAME: sslpassword_program
2019 LOC: Config.Program.ssl_password
2022 Specify a program used for entering SSL key passphrases
2023 when using encrypted SSL certificate keys. If not specified
2024 keys must either be unencrypted, or Squid started with the -N
2025 option to allow it to query interactively for the passphrase.
2027 The key file name is given as argument to the program allowing
2028 selection of the right password if you have multiple encrypted
2033 OPTIONS RELATING TO EXTERNAL SSL_CRTD
2034 -----------------------------------------------------------------------------
2037 NAME: sslcrtd_program
2040 DEFAULT: @DEFAULT_SSL_CRTD@ -s @DEFAULT_SSL_DB_DIR@ -M 4MB
2041 LOC: Ssl::TheConfig.ssl_crtd
2043 Specify the location and options of the executable for ssl_crtd process.
2044 @DEFAULT_SSL_CRTD@ program requires -s and -M parameters
2045 For more information use:
2046 @DEFAULT_SSL_CRTD@ -h
2049 NAME: sslcrtd_children
2050 TYPE: HelperChildConfig
2052 DEFAULT: 32 startup=5 idle=1
2053 LOC: Ssl::TheConfig.ssl_crtdChildren
2055 The maximum number of processes spawn to service ssl server.
2056 The maximum this may be safely set to is 32.
2058 The startup= and idle= options allow some measure of skew in your
2063 Sets the minimum number of processes to spawn when Squid
2064 starts or reconfigures. When set to zero the first request will
2065 cause spawning of the first child process to handle it.
2067 Starting too few children temporary slows Squid under load while it
2068 tries to spawn enough additional processes to cope with traffic.
2072 Sets a minimum of how many processes Squid is to try and keep available
2073 at all times. When traffic begins to rise above what the existing
2074 processes can handle this many more will be spawned up to the maximum
2075 configured. A minimum setting of 1 is required.
2077 You must have at least one ssl_crtd process.
2081 OPTIONS WHICH AFFECT THE NEIGHBOR SELECTION ALGORITHM
2082 -----------------------------------------------------------------------------
2090 To specify other caches in a hierarchy, use the format:
2092 cache_peer hostname type http-port icp-port [options]
2097 # hostname type port port options
2098 # -------------------- -------- ----- ----- -----------
2099 cache_peer parent.foo.net parent 3128 3130 default
2100 cache_peer sib1.foo.net sibling 3128 3130 proxy-only
2101 cache_peer sib2.foo.net sibling 3128 3130 proxy-only
2102 cache_peer example.com parent 80 0 no-query default
2103 cache_peer cdn.example.com sibling 3128 0
2105 type: either 'parent', 'sibling', or 'multicast'.
2107 proxy-port: The port number where the peer accept HTTP requests.
2108 For other Squid proxies this is usually 3128
2109 For web servers this is usually 80
2111 icp-port: Used for querying neighbor caches about objects.
2112 Set to 0 if the peer does not support ICP or HTCP.
2113 See ICP and HTCP options below for additional details.
2116 ==== ICP OPTIONS ====
2118 You MUST also set icp_port and icp_access explicitly when using these options.
2119 The defaults will prevent peer traffic using ICP.
2122 no-query Disable ICP queries to this neighbor.
2125 Indicates the named peer is a member of a multicast group.
2126 ICP queries will not be sent directly to the peer, but ICP
2127 replies will be accepted from it.
2129 closest-only Indicates that, for ICP_OP_MISS replies, we'll only forward
2130 CLOSEST_PARENT_MISSes and never FIRST_PARENT_MISSes.
2133 To only send ICP queries to this neighbor infrequently.
2134 This is used to keep the neighbor round trip time updated
2135 and is usually used in conjunction with weighted-round-robin.
2138 ==== HTCP OPTIONS ====
2140 You MUST also set htcp_port and htcp_access explicitly when using these options.
2141 The defaults will prevent peer traffic using HTCP.
2144 htcp Send HTCP, instead of ICP, queries to the neighbor.
2145 You probably also want to set the "icp-port" to 4827
2146 instead of 3130. This directive accepts a comma separated
2147 list of options described below.
2149 htcp=oldsquid Send HTCP to old Squid versions (2.5 or earlier).
2151 htcp=no-clr Send HTCP to the neighbor but without
2152 sending any CLR requests. This cannot be used with
2155 htcp=only-clr Send HTCP to the neighbor but ONLY CLR requests.
2156 This cannot be used with no-clr.
2159 Send HTCP to the neighbor including CLRs but only when
2160 they do not result from PURGE requests.
2163 Forward any HTCP CLR requests this proxy receives to the peer.
2166 ==== PEER SELECTION METHODS ====
2168 The default peer selection method is ICP, with the first responding peer
2169 being used as source. These options can be used for better load balancing.
2172 default This is a parent cache which can be used as a "last-resort"
2173 if a peer cannot be located by any of the peer-selection methods.
2174 If specified more than once, only the first is used.
2176 round-robin Load-Balance parents which should be used in a round-robin
2177 fashion in the absence of any ICP queries.
2178 weight=N can be used to add bias.
2180 weighted-round-robin
2181 Load-Balance parents which should be used in a round-robin
2182 fashion with the frequency of each parent being based on the
2183 round trip time. Closer parents are used more often.
2184 Usually used for background-ping parents.
2185 weight=N can be used to add bias.
2187 carp Load-Balance parents which should be used as a CARP array.
2188 The requests will be distributed among the parents based on the
2189 CARP load balancing hash function based on their weight.
2191 userhash Load-balance parents based on the client proxy_auth or ident username.
2193 sourcehash Load-balance parents based on the client source IP.
2196 To be used only for cache peers of type "multicast".
2197 ALL members of this multicast group have "sibling"
2198 relationship with it, not "parent". This is to a mulicast
2199 group when the requested object would be fetched only from
2200 a "parent" cache, anyway. It's useful, e.g., when
2201 configuring a pool of redundant Squid proxies, being
2202 members of the same multicast group.
2205 ==== PEER SELECTION OPTIONS ====
2207 weight=N use to affect the selection of a peer during any weighted
2208 peer-selection mechanisms.
2209 The weight must be an integer; default is 1,
2210 larger weights are favored more.
2211 This option does not affect parent selection if a peering
2212 protocol is not in use.
2214 basetime=N Specify a base amount to be subtracted from round trip
2216 It is subtracted before division by weight in calculating
2217 which parent to fectch from. If the rtt is less than the
2218 base time the rtt is set to a minimal value.
2220 ttl=N Specify a TTL to use when sending multicast ICP queries
2222 Only useful when sending to a multicast group.
2223 Because we don't accept ICP replies from random
2224 hosts, you must configure other group members as
2225 peers with the 'multicast-responder' option.
2227 no-delay To prevent access to this neighbor from influencing the
2230 digest-url=URL Tell Squid to fetch the cache digest (if digests are
2231 enabled) for this host from the specified URL rather
2232 than the Squid default location.
2235 ==== CARP OPTIONS ====
2237 carp-key=key-specification
2238 use a different key than the full URL to hash against the peer.
2239 the key-specification is a comma-separated list of the keywords
2240 scheme, host, port, path, params
2241 Order is not important.
2243 ==== ACCELERATOR / REVERSE-PROXY OPTIONS ====
2245 originserver Causes this parent to be contacted as an origin server.
2246 Meant to be used in accelerator setups when the peer
2250 Set the Host header of requests forwarded to this peer.
2251 Useful in accelerator setups where the server (peer)
2252 expects a certain domain name but clients may request
2253 others. ie example.com or www.example.com
2255 no-digest Disable request of cache digests.
2258 Disables requesting ICMP RTT database (NetDB).
2261 ==== AUTHENTICATION OPTIONS ====
2264 If this is a personal/workgroup proxy and your parent
2265 requires proxy authentication.
2267 Note: The string can include URL escapes (i.e. %20 for
2268 spaces). This also means % must be written as %%.
2271 Send login details received from client to this peer.
2272 Both Proxy- and WWW-Authorization headers are passed
2273 without alteration to the peer.
2274 Authentication is not required by Squid for this to work.
2276 Note: This will pass any form of authentication but
2277 only Basic auth will work through a proxy unless the
2278 connection-auth options are also used.
2280 login=PASS Send login details received from client to this peer.
2281 Authentication is not required by this option.
2283 If there are no client-provided authentication headers
2284 to pass on, but username and password are available
2285 from an external ACL user= and password= result tags
2286 they may be sent instead.
2288 Note: To combine this with proxy_auth both proxies must
2289 share the same user database as HTTP only allows for
2290 a single login (one for proxy, one for origin server).
2291 Also be warned this will expose your users proxy
2292 password to the peer. USE WITH CAUTION
2295 Send the username to the upstream cache, but with a
2296 fixed password. This is meant to be used when the peer
2297 is in another administrative domain, but it is still
2298 needed to identify each user.
2299 The star can optionally be followed by some extra
2300 information which is added to the username. This can
2301 be used to identify this proxy to the peer, similar to
2302 the login=username:password option above.
2305 If this is a personal/workgroup proxy and your parent
2306 requires a secure proxy authentication.
2307 The first principal from the default keytab or defined by
2308 the environment variable KRB5_KTNAME will be used.
2310 WARNING: The connection may transmit requests from multiple
2311 clients. Negotiate often assumes end-to-end authentication
2312 and a single-client. Which is not strictly true here.
2314 login=NEGOTIATE:principal_name
2315 If this is a personal/workgroup proxy and your parent
2316 requires a secure proxy authentication.
2317 The principal principal_name from the default keytab or
2318 defined by the environment variable KRB5_KTNAME will be
2321 WARNING: The connection may transmit requests from multiple
2322 clients. Negotiate often assumes end-to-end authentication
2323 and a single-client. Which is not strictly true here.
2325 connection-auth=on|off
2326 Tell Squid that this peer does or not support Microsoft
2327 connection oriented authentication, and any such
2328 challenges received from there should be ignored.
2329 Default is auto to automatically determine the status
2333 ==== SSL / HTTPS / TLS OPTIONS ====
2335 ssl Encrypt connections to this peer with SSL/TLS.
2337 sslcert=/path/to/ssl/certificate
2338 A client SSL certificate to use when connecting to
2341 sslkey=/path/to/ssl/key
2342 The private SSL key corresponding to sslcert above.
2343 If 'sslkey' is not specified 'sslcert' is assumed to
2344 reference a combined file containing both the
2345 certificate and the key.
2348 The SSL version to use when connecting to this peer
2349 1 = automatic (default)
2354 sslcipher=... The list of valid SSL ciphers to use when connecting
2357 ssloptions=... Specify various SSL engine options:
2358 NO_SSLv2 Disallow the use of SSLv2
2359 NO_SSLv3 Disallow the use of SSLv3
2360 NO_TLSv1 Disallow the use of TLSv1
2361 See src/ssl_support.c or the OpenSSL documentation for
2362 a more complete list.
2364 sslcafile=... A file containing additional CA certificates to use
2365 when verifying the peer certificate.
2367 sslcapath=... A directory containing additional CA certificates to
2368 use when verifying the peer certificate.
2370 sslcrlfile=... A certificate revocation list file to use when
2371 verifying the peer certificate.
2373 sslflags=... Specify various flags modifying the SSL implementation:
2376 Accept certificates even if they fail to
2379 Don't use the default CA list built in
2382 Don't verify the peer certificate
2383 matches the server name
2385 ssldomain= The peer name as advertised in it's certificate.
2386 Used for verifying the correctness of the received peer
2387 certificate. If not specified the peer hostname will be
2391 Enable the "Front-End-Https: On" header needed when
2392 using Squid as a SSL frontend in front of Microsoft OWA.
2393 See MS KB document Q307347 for details on this header.
2394 If set to auto the header will only be added if the
2395 request is forwarded as a https:// URL.
2398 ==== GENERAL OPTIONS ====
2401 A peer-specific connect timeout.
2402 Also see the peer_connect_timeout directive.
2404 connect-fail-limit=N
2405 How many times connecting to a peer must fail before
2406 it is marked as down. Default is 10.
2408 allow-miss Disable Squid's use of only-if-cached when forwarding
2409 requests to siblings. This is primarily useful when
2410 icp_hit_stale is used by the sibling. To extensive use
2411 of this option may result in forwarding loops, and you
2412 should avoid having two-way peerings with this option.
2413 For example to deny peer usage on requests from peer
2414 by denying cache_peer_access if the source is a peer.
2416 max-conn=N Limit the amount of connections Squid may open to this
2419 name=xxx Unique name for the peer.
2420 Required if you have multiple peers on the same host
2421 but different ports.
2422 This name can be used in cache_peer_access and similar
2423 directives to dentify the peer.
2424 Can be used by outgoing access controls through the
2427 no-tproxy Do not use the client-spoof TPROXY support when forwarding
2428 requests to this peer. Use normal address selection instead.
2430 proxy-only objects fetched from the peer will not be stored locally.
2434 NAME: cache_peer_domain cache_host_domain
2439 Use to limit the domains for which a neighbor cache will be
2442 cache_peer_domain cache-host domain [domain ...]
2443 cache_peer_domain cache-host !domain
2445 For example, specifying
2447 cache_peer_domain parent.foo.net .edu
2449 has the effect such that UDP query packets are sent to
2450 'bigserver' only when the requested object exists on a
2451 server in the .edu domain. Prefixing the domainname
2452 with '!' means the cache will be queried for objects
2455 NOTE: * Any number of domains may be given for a cache-host,
2456 either on the same or separate lines.
2457 * When multiple domains are given for a particular
2458 cache-host, the first matched domain is applied.
2459 * Cache hosts with no domain restrictions are queried
2461 * There are no defaults.
2462 * There is also a 'cache_peer_access' tag in the ACL
2466 NAME: cache_peer_access
2471 Similar to 'cache_peer_domain' but provides more flexibility by
2474 cache_peer_access cache-host allow|deny [!]aclname ...
2476 The syntax is identical to 'http_access' and the other lists of
2477 ACL elements. See the comments for 'http_access' below, or
2478 the Squid FAQ (http://wiki.squid-cache.org/SquidFaq/SquidAcl).
2481 NAME: neighbor_type_domain
2482 TYPE: hostdomaintype
2486 usage: neighbor_type_domain neighbor parent|sibling domain domain ...
2488 Modifying the neighbor type for specific domains is now
2489 possible. You can treat some domains differently than the
2490 default neighbor type specified on the 'cache_peer' line.
2491 Normally it should only be necessary to list domains which
2492 should be treated differently because the default neighbor type
2493 applies for hostnames which do not match domains listed here.
2496 cache_peer cache.foo.org parent 3128 3130
2497 neighbor_type_domain cache.foo.org sibling .com .net
2498 neighbor_type_domain cache.foo.org sibling .au .de
2501 NAME: dead_peer_timeout
2505 LOC: Config.Timeout.deadPeer
2507 This controls how long Squid waits to declare a peer cache
2508 as "dead." If there are no ICP replies received in this
2509 amount of time, Squid will declare the peer dead and not
2510 expect to receive any further ICP replies. However, it
2511 continues to send ICP queries, and will mark the peer as
2512 alive upon receipt of the first subsequent ICP reply.
2514 This timeout also affects when Squid expects to receive ICP
2515 replies from peers. If more than 'dead_peer' seconds have
2516 passed since the last ICP reply was received, Squid will not
2517 expect to receive an ICP reply on the next query. Thus, if
2518 your time between requests is greater than this timeout, you
2519 will see a lot of requests sent DIRECT to origin servers
2520 instead of to your parents.
2523 NAME: forward_max_tries
2526 LOC: Config.forward_max_tries
2528 Controls how many different forward paths Squid will try
2529 before giving up. See also forward_timeout.
2531 NOTE: connect_retries (default: none) can make each of these
2532 possible forwarding paths be tried multiple times.
2535 NAME: hierarchy_stoplist
2538 LOC: Config.hierarchy_stoplist
2540 A list of words which, if found in a URL, cause the object to
2541 be handled directly by this cache. In other words, use this
2542 to not query neighbor caches for certain objects. You may
2543 list this option multiple times.
2546 hierarchy_stoplist cgi-bin ?
2548 Note: never_direct overrides this option.
2552 MEMORY CACHE OPTIONS
2553 -----------------------------------------------------------------------------
2560 LOC: Config.memMaxSize
2562 NOTE: THIS PARAMETER DOES NOT SPECIFY THE MAXIMUM PROCESS SIZE.
2563 IT ONLY PLACES A LIMIT ON HOW MUCH ADDITIONAL MEMORY SQUID WILL
2564 USE AS A MEMORY CACHE OF OBJECTS. SQUID USES MEMORY FOR OTHER
2565 THINGS AS WELL. SEE THE SQUID FAQ SECTION 8 FOR DETAILS.
2567 'cache_mem' specifies the ideal amount of memory to be used
2569 * In-Transit objects
2571 * Negative-Cached objects
2573 Data for these objects are stored in 4 KB blocks. This
2574 parameter specifies the ideal upper limit on the total size of
2575 4 KB blocks allocated. In-Transit objects take the highest
2578 In-transit objects have priority over the others. When
2579 additional space is needed for incoming data, negative-cached
2580 and hot objects will be released. In other words, the
2581 negative-cached and hot objects will fill up any unused space
2582 not needed for in-transit objects.
2584 If circumstances require, this limit will be exceeded.
2585 Specifically, if your incoming request rate requires more than
2586 'cache_mem' of memory to hold in-transit objects, Squid will
2587 exceed this limit to satisfy the new requests. When the load
2588 decreases, blocks will be freed until the high-water mark is
2589 reached. Thereafter, blocks will be used to store hot
2592 If shared memory caching is enabled, Squid does not use the shared
2593 cache space for in-transit objects, but they still consume as much
2594 local memory as they need. For more details about the shared memory
2595 cache, see memory_cache_shared.
2598 NAME: maximum_object_size_in_memory
2602 LOC: Config.Store.maxInMemObjSize
2604 Objects greater than this size will not be attempted to kept in
2605 the memory cache. This should be set high enough to keep objects
2606 accessed frequently in memory to improve performance whilst low
2607 enough to keep larger objects from hoarding cache_mem.
2610 NAME: memory_cache_shared
2613 LOC: Config.memShared
2615 DEFAULT_DOC: "on" where supported if doing memory caching with multiple SMP workers.
2617 Controls whether the memory cache is shared among SMP workers.
2619 The shared memory cache is meant to occupy cache_mem bytes and replace
2620 the non-shared memory cache, although some entities may still be
2621 cached locally by workers for now (e.g., internal and in-transit
2622 objects may be served from a local memory cache even if shared memory
2623 caching is enabled).
2625 By default, the memory cache is shared if and only if all of the
2626 following conditions are satisfied: Squid runs in SMP mode with
2627 multiple workers, cache_mem is positive, and Squid environment
2628 supports required IPC primitives (e.g., POSIX shared memory segments
2629 and GCC-style atomic operations).
2631 To avoid blocking locks, shared memory uses opportunistic algorithms
2632 that do not guarantee that every cachable entity that could have been
2633 shared among SMP workers will actually be shared.
2635 Currently, entities exceeding 32KB in size cannot be shared.
2638 NAME: memory_cache_mode
2643 Controls which objects to keep in the memory cache (cache_mem)
2645 always Keep most recently fetched objects in memory (default)
2647 disk Only disk cache hits are kept in memory, which means
2648 an object must first be cached on disk and then hit
2649 a second time before cached in memory.
2651 network Only objects fetched from network is kept in memory
2654 NAME: memory_replacement_policy
2656 LOC: Config.memPolicy
2659 The memory replacement policy parameter determines which
2660 objects are purged from memory when memory space is needed.
2662 See cache_replacement_policy for details.
2667 -----------------------------------------------------------------------------
2670 NAME: cache_replacement_policy
2672 LOC: Config.replPolicy
2675 The cache replacement policy parameter determines which
2676 objects are evicted (replaced) when disk space is needed.
2678 lru : Squid's original list based LRU policy
2679 heap GDSF : Greedy-Dual Size Frequency
2680 heap LFUDA: Least Frequently Used with Dynamic Aging
2681 heap LRU : LRU policy implemented using a heap
2683 Applies to any cache_dir lines listed below this.
2685 The LRU policies keeps recently referenced objects.
2687 The heap GDSF policy optimizes object hit rate by keeping smaller
2688 popular objects in cache so it has a better chance of getting a
2689 hit. It achieves a lower byte hit rate than LFUDA though since
2690 it evicts larger (possibly popular) objects.
2692 The heap LFUDA policy keeps popular objects in cache regardless of
2693 their size and thus optimizes byte hit rate at the expense of
2694 hit rate since one large, popular object will prevent many
2695 smaller, slightly less popular objects from being cached.
2697 Both policies utilize a dynamic aging mechanism that prevents
2698 cache pollution that can otherwise occur with frequency-based
2699 replacement policies.
2701 NOTE: if using the LFUDA replacement policy you should increase
2702 the value of maximum_object_size above its default of 4096 KB to
2703 to maximize the potential byte hit rate improvement of LFUDA.
2705 For more information about the GDSF and LFUDA cache replacement
2706 policies see http://www.hpl.hp.com/techreports/1999/HPL-1999-69.html
2707 and http://fog.hpl.external.hp.com/techreports/98/HPL-98-173.html.
2713 LOC: Config.cacheSwap
2717 cache_dir Type Directory-Name Fs-specific-data [options]
2719 You can specify multiple cache_dir lines to spread the
2720 cache among different disk partitions.
2722 Type specifies the kind of storage system to use. Only "ufs"
2723 is built by default. To enable any of the other storage systems
2724 see the --enable-storeio configure option.
2726 'Directory' is a top-level directory where cache swap
2727 files will be stored. If you want to use an entire disk
2728 for caching, this can be the mount-point directory.
2729 The directory must exist and be writable by the Squid
2730 process. Squid will NOT create this directory for you.
2732 In SMP configurations, cache_dir must not precede the workers option
2733 and should use configuration macros or conditionals to give each
2734 worker interested in disk caching a dedicated cache directory.
2738 "ufs" is the old well-known Squid storage format that has always
2741 cache_dir ufs Directory-Name Mbytes L1 L2 [options]
2743 'Mbytes' is the amount of disk space (MB) to use under this
2744 directory. The default is 100 MB. Change this to suit your
2745 configuration. Do NOT put the size of your disk drive here.
2746 Instead, if you want Squid to use the entire disk drive,
2747 subtract 20% and use that value.
2749 'L1' is the number of first-level subdirectories which
2750 will be created under the 'Directory'. The default is 16.
2752 'L2' is the number of second-level subdirectories which
2753 will be created under each first-level directory. The default
2756 The aufs store type:
2758 "aufs" uses the same storage format as "ufs", utilizing
2759 POSIX-threads to avoid blocking the main Squid process on
2760 disk-I/O. This was formerly known in Squid as async-io.
2762 cache_dir aufs Directory-Name Mbytes L1 L2 [options]
2764 see argument descriptions under ufs above
2766 The diskd store type:
2768 "diskd" uses the same storage format as "ufs", utilizing a
2769 separate process to avoid blocking the main Squid process on
2772 cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n]
2774 see argument descriptions under ufs above
2776 Q1 specifies the number of unacknowledged I/O requests when Squid
2777 stops opening new files. If this many messages are in the queues,
2778 Squid won't open new files. Default is 64
2780 Q2 specifies the number of unacknowledged messages when Squid
2781 starts blocking. If this many messages are in the queues,
2782 Squid blocks until it receives some replies. Default is 72
2784 When Q1 < Q2 (the default), the cache directory is optimized
2785 for lower response time at the expense of a decrease in hit
2786 ratio. If Q1 > Q2, the cache directory is optimized for
2787 higher hit ratio at the expense of an increase in response
2790 The rock store type:
2792 cache_dir rock Directory-Name Mbytes <max-size=bytes> [options]
2794 The Rock Store type is a database-style storage. All cached
2795 entries are stored in a "database" file, using fixed-size slots,
2796 one entry per slot. The database size is specified in MB. The
2797 slot size is specified in bytes using the max-size option. See
2798 below for more info on the max-size option.
2800 swap-timeout=msec: Squid will not start writing a miss to or
2801 reading a hit from disk if it estimates that the swap operation
2802 will take more than the specified number of milliseconds. By
2803 default and when set to zero, disables the disk I/O time limit
2804 enforcement. Ignored when using blocking I/O module because
2805 blocking synchronous I/O does not allow Squid to estimate the
2806 expected swap wait time.
2808 max-swap-rate=swaps/sec: Artificially limits disk access using
2809 the specified I/O rate limit. Swap out requests that
2810 would cause the average I/O rate to exceed the limit are
2811 delayed. Individual swap in requests (i.e., hits or reads) are
2812 not delayed, but they do contribute to measured swap rate and
2813 since they are placed in the same FIFO queue as swap out
2814 requests, they may wait longer if max-swap-rate is smaller.
2815 This is necessary on file systems that buffer "too
2816 many" writes and then start blocking Squid and other processes
2817 while committing those writes to disk. Usually used together
2818 with swap-timeout to avoid excessive delays and queue overflows
2819 when disk demand exceeds available disk "bandwidth". By default
2820 and when set to zero, disables the disk I/O rate limit
2821 enforcement. Currently supported by IpcIo module only.
2824 The coss store type:
2826 NP: COSS filesystem in Squid-3 has been deemed too unstable for
2827 production use and has thus been removed from this release.
2828 We hope that it can be made usable again soon.
2830 block-size=n defines the "block size" for COSS cache_dir's.
2831 Squid uses file numbers as block numbers. Since file numbers
2832 are limited to 24 bits, the block size determines the maximum
2833 size of the COSS partition. The default is 512 bytes, which
2834 leads to a maximum cache_dir size of 512<<24, or 8 GB. Note
2835 you should not change the coss block size after Squid
2836 has written some objects to the cache_dir.
2838 The coss file store has changed from 2.5. Now it uses a file
2839 called 'stripe' in the directory names in the config - and
2840 this will be created by squid -z.
2844 no-store, no new objects should be stored to this cache_dir
2846 min-size=n, refers to the min object size in bytes this cache_dir
2847 will accept. It's used to restrict a cache_dir to only store
2848 large objects (e.g. aufs) while other storedirs are optimized
2849 for smaller objects (e.g. COSS). Defaults to 0.
2851 max-size=n, refers to the max object size in bytes this cache_dir
2852 supports. It is used to select the cache_dir to store the object.
2853 Note: To make optimal use of the max-size limits you should order
2854 the cache_dir lines with the smallest max-size value first and the
2855 ones with no max-size specification last.
2857 Note for coss, max-size must be less than COSS_MEMBUF_SZ,
2858 which can be changed with the --with-coss-membuf-size=N configure
2862 # Uncomment and adjust the following to add a disk cache directory.
2863 #cache_dir ufs @DEFAULT_SWAP_DIR@ 100 16 256
2867 NAME: store_dir_select_algorithm
2869 LOC: Config.store_dir_select_algorithm
2872 Set this to 'round-robin' as an alternative.
2875 NAME: max_open_disk_fds
2877 LOC: Config.max_open_disk_fds
2880 To avoid having disk as the I/O bottleneck Squid can optionally
2881 bypass the on-disk cache if more than this amount of disk file
2882 descriptors are open.
2884 A value of 0 indicates no limit.
2887 NAME: minimum_object_size
2891 LOC: Config.Store.minObjectSize
2893 Objects smaller than this size will NOT be saved on disk. The
2894 value is specified in kilobytes, and the default is 0 KB, which
2895 means there is no minimum.
2898 NAME: maximum_object_size
2902 LOC: Config.Store.maxObjectSize
2904 Objects larger than this size will NOT be saved on disk. The
2905 value is specified in kilobytes, and the default is 4MB. If
2906 you wish to get a high BYTES hit ratio, you should probably
2907 increase this (one 32 MB object hit counts for 3200 10KB
2908 hits). If you wish to increase speed more than your want to
2909 save bandwidth you should leave this low.
2911 NOTE: if using the LFUDA replacement policy you should increase
2912 this value to maximize the byte hit rate improvement of LFUDA!
2913 See replacement_policy below for a discussion of this policy.
2916 NAME: cache_swap_low
2917 COMMENT: (percent, 0-100)
2920 LOC: Config.Swap.lowWaterMark
2923 NAME: cache_swap_high
2924 COMMENT: (percent, 0-100)
2927 LOC: Config.Swap.highWaterMark
2930 The low- and high-water marks for cache object replacement.
2931 Replacement begins when the swap (disk) usage is above the
2932 low-water mark and attempts to maintain utilization near the
2933 low-water mark. As swap utilization gets close to high-water
2934 mark object eviction becomes more aggressive. If utilization is
2935 close to the low-water mark less replacement is done each time.
2937 Defaults are 90% and 95%. If you have a large cache, 5% could be
2938 hundreds of MB. If this is the case you may wish to set these
2939 numbers closer together.
2944 -----------------------------------------------------------------------------
2954 logformat <name> <format specification>
2956 Defines an access log format.
2958 The <format specification> is a string with embedded % format codes
2960 % format codes all follow the same basic structure where all but
2961 the formatcode is optional. Output strings are automatically escaped
2962 as required according to their context and the output format
2963 modifiers are usually not needed, but can be specified if an explicit
2964 output format is desired.
2966 % ["|[|'|#] [-] [[0]width] [{argument}] formatcode
2968 " output in quoted string format
2969 [ output in squid text log format as used by log_mime_hdrs
2970 # output in URL quoted format
2975 width minimum and/or maximum field width:
2976 [width_min][.width_max]
2977 When minimum starts with 0, the field is zero-padded.
2978 String values exceeding maximum width are truncated.
2980 {arg} argument such as header name etc
2984 % a literal % character
2985 sn Unique sequence number per log line entry
2986 err_code The ID of an error response served by Squid or
2987 a similar internal error identifier.
2988 err_detail Additional err_code-dependent error information.
2990 Connection related format codes:
2992 >a Client source IP address
2994 >p Client source port
2995 >eui Client source EUI (MAC address, EUI-48 or EUI-64 identifier)
2996 >la Local IP address the client connected to
2997 >lp Local port number the client connected to
2999 la Local listening IP address the client connection was connected to.
3000 lp Local listening port number the client connection was connected to.
3002 <a Server IP address of the last server or peer connection
3003 <A Server FQDN or peer name
3004 <p Server port number of the last server or peer connection
3005 <la Local IP address of the last server or peer connection
3006 <lp Local port number of the last server or peer connection
3008 Time related format codes:
3010 ts Seconds since epoch
3011 tu subsecond time (milliseconds)
3012 tl Local time. Optional strftime format argument
3013 default %d/%b/%Y:%H:%M:%S %z
3014 tg GMT time. Optional strftime format argument
3015 default %d/%b/%Y:%H:%M:%S %z
3016 tr Response time (milliseconds)
3017 dt Total time spent making DNS lookups (milliseconds)
3019 Access Control related format codes:
3021 et Tag returned by external acl
3022 ea Log string returned by external acl
3023 un User name (any available)
3024 ul User name from authentication
3025 ue User name from external acl helper
3026 ui User name from ident
3027 us User name from SSL
3029 HTTP related format codes:
3031 [http::]>h Original request header. Optional header name argument
3032 on the format header[:[separator]element]
3033 [http::]>ha The HTTP request headers after adaptation and redirection.
3034 Optional header name argument as for >h
3035 [http::]<h Reply header. Optional header name argument
3037 [http::]>Hs HTTP status code sent to the client
3038 [http::]<Hs HTTP status code received from the next hop
3039 [http::]<bs Number of HTTP-equivalent message body bytes
3040 received from the next hop, excluding chunked
3041 transfer encoding and control messages.
3042 Generated FTP/Gopher listings are treated as
3044 [http::]mt MIME content type
3045 [http::]rm Request method (GET/POST etc)
3046 [http::]>rm Request method from client
3047 [http::]<rm Request method sent to server or peer
3048 [http::]ru Request URL from client (historic, filtered for logging)
3049 [http::]>ru Request URL from client
3050 [http::]<ru Request URL sent to server or peer
3051 [http::]rp Request URL-Path excluding hostname
3052 [http::]>rp Request URL-Path excluding hostname from client
3053 [http::]<rp Request URL-Path excluding hostname sento to server or peer
3054 [http::]rv Request protocol version
3055 [http::]>rv Request protocol version from client
3056 [http::]<rv Request protocol version sent to server or peer
3057 [http::]<st Sent reply size including HTTP headers
3058 [http::]>st Received request size including HTTP headers. In the
3059 case of chunked requests the chunked encoding metadata
3061 [http::]>sh Received HTTP request headers size
3062 [http::]<sh Sent HTTP reply headers size
3063 [http::]st Request+Reply size including HTTP headers
3064 [http::]<sH Reply high offset sent
3065 [http::]<sS Upstream object size
3066 [http::]<pt Peer response time in milliseconds. The timer starts
3067 when the last request byte is sent to the next hop
3068 and stops when the last response byte is received.
3069 [http::]<tt Total server-side time in milliseconds. The timer
3070 starts with the first connect request (or write I/O)
3071 sent to the first selected peer. The timer stops
3072 with the last I/O with the last peer.
3074 Squid handling related format codes:
3076 Ss Squid request status (TCP_MISS etc)
3077 Sh Squid hierarchy status (DEFAULT_PARENT etc)
3079 If ICAP is enabled, the following code becomes available (as
3080 well as ICAP log codes documented with the icap_log option):
3082 icap::tt Total ICAP processing time for the HTTP
3083 transaction. The timer ticks when ICAP
3084 ACLs are checked and when ICAP
3085 transaction is in progress.
3087 If adaptation is enabled the following three codes become available:
3089 adapt::<last_h The header of the last ICAP response or
3090 meta-information from the last eCAP
3091 transaction related to the HTTP transaction.
3092 Like <h, accepts an optional header name
3095 adapt::sum_trs Summed adaptation transaction response
3096 times recorded as a comma-separated list in
3097 the order of transaction start time. Each time
3098 value is recorded as an integer number,
3099 representing response time of one or more
3100 adaptation (ICAP or eCAP) transaction in
3101 milliseconds. When a failed transaction is
3102 being retried or repeated, its time is not
3103 logged individually but added to the
3104 replacement (next) transaction. See also:
3107 adapt::all_trs All adaptation transaction response times.
3108 Same as adaptation_strs but response times of
3109 individual transactions are never added
3110 together. Instead, all transaction response
3111 times are recorded individually.
3113 You can prefix adapt::*_trs format codes with adaptation
3114 service name in curly braces to record response time(s) specific
3115 to that service. For example: %{my_service}adapt::sum_trs
3117 The default formats available (which do not need re-defining) are:
3119 logformat squid %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %[un %Sh/%<a %mt
3120 logformat common %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st %Ss:%Sh
3121 logformat combined %>a %[ui %[un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
3122 logformat referrer %ts.%03tu %>a %{Referer}>h %ru
3123 logformat useragent %>a [%tl] "%{User-Agent}>h"
3125 NOTE: When the log_mime_hdrs directive is set to ON.
3126 The squid, common and combined formats have a safely encoded copy
3127 of the mime headers appended to each line within a pair of brackets.
3129 NOTE: The common and combined formats are not quite true to the Apache definition.
3130 The logs from Squid contain an extra status and hierarchy code appended.
3134 NAME: access_log cache_access_log
3136 LOC: Config.Log.accesslogs
3137 DEFAULT_IF_NONE: daemon:@DEFAULT_ACCESS_LOG@ squid
3139 These files log client request activities. Has a line every HTTP or
3140 ICP request. The format is:
3141 access_log <module>:<place> [<logformat name> [acl acl ...]]
3142 access_log none [acl acl ...]]
3144 Will log to the specified module:place using the specified format (which
3145 must be defined in a logformat directive) those entries which match
3146 ALL the acl's specified (which must be defined in acl clauses).
3147 If no acl is specified, all requests will be logged to this destination.
3149 ===== Modules Currently available =====
3151 none Do not log any requests matching these ACL.
3152 Do not specify Place or logformat name.
3154 stdio Write each log line to disk immediately at the completion of
3156 Place: the filename and path to be written.
3158 daemon Very similar to stdio. But instead of writing to disk the log
3159 line is passed to a daemon helper for asychronous handling instead.
3160 Place: varies depending on the daemon.
3162 log_file_daemon Place: the file name and path to be written.
3164 syslog To log each request via syslog facility.
3165 Place: The syslog facility and priority level for these entries.
3166 Place Format: facility.priority
3168 where facility could be any of:
3169 authpriv, daemon, local0 ... local7 or user.
3171 And priority could be any of:
3172 err, warning, notice, info, debug.
3174 udp To send each log line as text data to a UDP receiver.
3175 Place: The destination host name or IP and port.
3176 Place Format: \\host:port
3178 tcp To send each log line as text data to a TCP receiver.
3179 Place: The destination host name or IP and port.
3180 Place Format: \\host:port
3183 access_log daemon:@DEFAULT_ACCESS_LOG@ squid
3189 LOC: Config.Log.icaplogs
3192 ICAP log files record ICAP transaction summaries, one line per
3195 The icap_log option format is:
3196 icap_log <filepath> [<logformat name> [acl acl ...]]
3197 icap_log none [acl acl ...]]
3199 Please see access_log option documentation for details. The two
3200 kinds of logs share the overall configuration approach and many
3203 ICAP processing of a single HTTP message or transaction may
3204 require multiple ICAP transactions. In such cases, multiple
3205 ICAP transaction log lines will correspond to a single access
3208 ICAP log uses logformat codes that make sense for an ICAP
3209 transaction. Header-related codes are applied to the HTTP header
3210 embedded in an ICAP server response, with the following caveats:
3211 For REQMOD, there is no HTTP response header unless the ICAP
3212 server performed request satisfaction. For RESPMOD, the HTTP
3213 request header is the header sent to the ICAP server. For
3214 OPTIONS, there are no HTTP headers.
3216 The following format codes are also available for ICAP logs:
3218 icap::<A ICAP server IP address. Similar to <A.
3220 icap::<service_name ICAP service name from the icap_service
3221 option in Squid configuration file.
3223 icap::ru ICAP Request-URI. Similar to ru.
3225 icap::rm ICAP request method (REQMOD, RESPMOD, or
3226 OPTIONS). Similar to existing rm.
3228 icap::>st Bytes sent to the ICAP server (TCP payload
3229 only; i.e., what Squid writes to the socket).
3231 icap::<st Bytes received from the ICAP server (TCP
3232 payload only; i.e., what Squid reads from
3235 icap::<bs Number of message body bytes received from the
3236 ICAP server. ICAP message body, if any, usually
3237 includes encapsulated HTTP message headers and
3238 possibly encapsulated HTTP message body. The
3239 HTTP body part is dechunked before its size is
3242 icap::tr Transaction response time (in
3243 milliseconds). The timer starts when
3244 the ICAP transaction is created and
3245 stops when the transaction is completed.
3248 icap::tio Transaction I/O time (in milliseconds). The
3249 timer starts when the first ICAP request
3250 byte is scheduled for sending. The timers
3251 stops when the last byte of the ICAP response
3254 icap::to Transaction outcome: ICAP_ERR* for all
3255 transaction errors, ICAP_OPT for OPTION
3256 transactions, ICAP_ECHO for 204
3257 responses, ICAP_MOD for message
3258 modification, and ICAP_SAT for request
3259 satisfaction. Similar to Ss.
3261 icap::Hs ICAP response status code. Similar to Hs.
3263 icap::>h ICAP request header(s). Similar to >h.
3265 icap::<h ICAP response header(s). Similar to <h.
3267 The default ICAP log format, which can be used without an explicit
3268 definition, is called icap_squid:
3270 logformat icap_squid %ts.%03tu %6icap::tr %>a %icap::to/%03icap::Hs %icap::<size %icap::rm %icap::ru% %un -/%icap::<A -
3272 See also: logformat, log_icap, and %adapt::<last_h
3275 NAME: logfile_daemon
3277 DEFAULT: @DEFAULT_LOGFILED@
3278 LOC: Log::TheConfig.logfile_daemon
3280 Specify the path to the logfile-writing daemon. This daemon is
3281 used to write the access and store logs, if configured.
3283 Squid sends a number of commands to the log daemon:
3284 L<data>\n - logfile data
3289 r<n>\n - set rotate count to <n>
3290 b<n>\n - 1 = buffer output, 0 = don't buffer output
3292 No responses is expected.
3297 LOC: Config.accessList.log
3299 COMMENT: allow|deny acl acl...
3301 This options allows you to control which requests gets logged
3302 to access.log (see access_log directive). Requests denied for
3303 logging will also not be accounted for in performance counters.
3305 This clause only supports fast acl types.
3306 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
3312 LOC: Config.accessList.icap
3315 This options allows you to control which requests get logged
3316 to icap.log. See the icap_log directive for ICAP log details.
3319 NAME: cache_store_log
3322 LOC: Config.Log.store
3324 Logs the activities of the storage manager. Shows which
3325 objects are ejected from the cache, and which objects are
3326 saved and for how long. To disable, enter "none" or remove the line.
3327 There are not really utilities to analyze this data, so you can safely
3331 cache_store_log @DEFAULT_STORE_LOG@
3334 NAME: cache_swap_state cache_swap_log
3336 LOC: Config.Log.swap
3339 Location for the cache "swap.state" file. This index file holds
3340 the metadata of objects saved on disk. It is used to rebuild
3341 the cache during startup. Normally this file resides in each
3342 'cache_dir' directory, but you may specify an alternate
3343 pathname here. Note you must give a full filename, not just
3344 a directory. Since this is the index for the whole object
3345 list you CANNOT periodically rotate it!
3347 If %s can be used in the file name it will be replaced with a
3348 a representation of the cache_dir name where each / is replaced
3349 with '.'. This is needed to allow adding/removing cache_dir
3350 lines when cache_swap_log is being used.
3352 If have more than one 'cache_dir', and %s is not used in the name
3353 these swap logs will have names such as:
3359 The numbered extension (which is added automatically)
3360 corresponds to the order of the 'cache_dir' lines in this
3361 configuration file. If you change the order of the 'cache_dir'
3362 lines in this file, these index files will NOT correspond to
3363 the correct 'cache_dir' entry (unless you manually rename
3364 them). We recommend you do NOT use this option. It is
3365 better to keep these index files in each 'cache_dir' directory.
3368 NAME: logfile_rotate
3371 LOC: Config.Log.rotateNumber
3373 Specifies the number of logfile rotations to make when you
3374 type 'squid -k rotate'. The default is 10, which will rotate
3375 with extensions 0 through 9. Setting logfile_rotate to 0 will
3376 disable the file name rotation, but the logfiles are still closed
3377 and re-opened. This will enable you to rename the logfiles
3378 yourself just before sending the rotate signal.
3380 Note, the 'squid -k rotate' command normally sends a USR1
3381 signal to the running squid process. In certain situations
3382 (e.g. on Linux with Async I/O), USR1 is used for other
3383 purposes, so -k rotate uses another signal. It is best to get
3384 in the habit of using 'squid -k rotate' instead of 'kill -USR1
3387 Note, from Squid-3.1 this option has no effect on the cache.log,
3388 that log can be rotated separately by using debug_options
3391 NAME: emulate_httpd_log
3394 Replace this with an access_log directive using the format 'common' or 'combined'.
3397 NAME: log_ip_on_direct
3400 Remove this option from your config. To log server or peer names use %<A in the log format.
3405 DEFAULT: @DEFAULT_MIME_TABLE@
3406 LOC: Config.mimeTablePathname
3408 Pathname to Squid's MIME table. You shouldn't need to change
3409 this, but the default file contains examples and formatting
3410 information if you do.
3416 LOC: Config.onoff.log_mime_hdrs
3419 The Cache can record both the request and the response MIME
3420 headers for each HTTP transaction. The headers are encoded
3421 safely and will appear as two bracketed fields at the end of
3422 the access log (for either the native or httpd-emulated log
3423 formats). To enable this logging set log_mime_hdrs to 'on'.
3429 Replace this with an access_log directive using the format 'useragent'.
3432 NAME: referer_log referrer_log
3435 Replace this with an access_log directive using the format 'referrer'.
3440 DEFAULT: @DEFAULT_PID_FILE@
3441 LOC: Config.pidFilename
3443 A filename to write the process-id to. To disable, enter "none".
3449 Remove this option from your config. To log FQDN use %>A in the log format.
3452 NAME: client_netmask
3454 LOC: Config.Addrs.client_netmask
3457 A netmask for client addresses in logfiles and cachemgr output.
3458 Change this to protect the privacy of your cache clients.
3459 A netmask of 255.255.255.0 will log all IP's in that range with
3460 the last digit set to '0'.
3466 Use a regular access.log with ACL limiting it to MISS events.
3469 NAME: strip_query_terms
3471 LOC: Config.onoff.strip_query_terms
3474 By default, Squid strips query terms from requested URLs before
3475 logging. This protects your user's privacy.
3482 LOC: Config.onoff.buffered_logs
3484 cache.log log file is written with stdio functions, and as such
3485 it can be buffered or unbuffered. By default it will be unbuffered.
3486 Buffering it can speed up the writing slightly (though you are
3487 unlikely to need to worry unless you run with tons of debugging
3488 enabled in which case performance will suffer badly anyway..).
3491 NAME: netdb_filename
3493 DEFAULT: stdio:@DEFAULT_NETDB_FILE@
3494 LOC: Config.netdbFilename
3497 A filename where Squid stores it's netdb state between restarts.
3498 To disable, enter "none".
3502 OPTIONS FOR TROUBLESHOOTING
3503 -----------------------------------------------------------------------------
3508 DEFAULT_IF_NONE: @DEFAULT_CACHE_LOG@
3509 LOC: Debug::cache_log
3511 Cache logging file. This is where general information about
3512 your cache's behavior goes. You can increase the amount of data
3513 logged to this file and how often its rotated with "debug_options"
3519 LOC: Debug::debugOptions
3521 Logging options are set as section,level where each source file
3522 is assigned a unique section. Lower levels result in less
3523 output, Full debugging (level 9) can result in a very large
3524 log file, so be careful.
3526 The magic word "ALL" sets debugging levels for all sections.
3527 We recommend normally running with "ALL,1".
3529 The rotate=N option can be used to keep more or less of these logs
3530 than would otherwise be kept by logfile_rotate.
3531 For most uses a single log should be enough to monitor current
3532 events affecting Squid.
3537 LOC: Config.coredump_dir
3538 DEFAULT_IF_NONE: none
3540 By default Squid leaves core files in the directory from where
3541 it was started. If you set 'coredump_dir' to a directory
3542 that exists, Squid will chdir() to that directory at startup
3543 and coredump files will be left there.
3547 # Leave coredumps in the first cache dir
3548 coredump_dir @DEFAULT_SWAP_DIR@
3554 OPTIONS FOR FTP GATEWAYING
3555 -----------------------------------------------------------------------------
3561 LOC: Config.Ftp.anon_user
3563 If you want the anonymous login password to be more informative
3564 (and enable the use of picky ftp servers), set this to something
3565 reasonable for your domain, like wwwuser@somewhere.net
3567 The reason why this is domainless by default is the
3568 request can be made on the behalf of a user in any domain,
3569 depending on how the cache is used.
3570 Some ftp server also validate the email address is valid
3571 (for example perl.com).
3577 LOC: Config.Ftp.passive
3579 If your firewall does not allow Squid to use passive
3580 connections, turn off this option.
3582 Use of ftp_epsv_all option requires this to be ON.
3588 LOC: Config.Ftp.epsv_all
3590 FTP Protocol extensions permit the use of a special "EPSV ALL" command.
3592 NATs may be able to put the connection on a "fast path" through the
3593 translator, as the EPRT command will never be used and therefore,
3594 translation of the data portion of the segments will never be needed.
3596 When a client only expects to do two-way FTP transfers this may be
3598 If squid finds that it must do a three-way FTP transfer after issuing
3599 an EPSV ALL command, the FTP session will fail.
3601 If you have any doubts about this option do not use it.
3602 Squid will nicely attempt all other connection methods.
3604 Requires ftp_passive to be ON (default) for any effect.
3610 LOC: Config.Ftp.epsv
3612 FTP Protocol extensions permit the use of a special "EPSV" command.
3614 NATs may be able to put the connection on a "fast path" through the
3615 translator using EPSV, as the EPRT command will never be used
3616 and therefore, translation of the data portion of the segments
3617 will never be needed.
3619 Turning this OFF will prevent EPSV being attempted.
3620 WARNING: Doing so will convert Squid back to the old behavior with all
3621 the related problems with external NAT devices/layers.
3623 Requires ftp_passive to be ON (default) for any effect.
3629 LOC: Config.Ftp.eprt
3631 FTP Protocol extensions permit the use of a special "EPRT" command.
3633 This extension provides a protocol neutral alternative to the
3634 IPv4-only PORT command. When supported it enables active FTP data
3635 channels over IPv6 and efficient NAT handling.
3637 Turning this OFF will prevent EPRT being attempted and will skip
3638 straight to using PORT for IPv4 servers.
3640 Some devices are known to not handle this extension correctly and
3641 may result in crashes. Devices which suport EPRT enough to fail
3642 cleanly will result in Squid attempting PORT anyway. This directive
3643 should only be disabled when EPRT results in device failures.
3645 WARNING: Doing so will convert Squid back to the old behavior with all
3646 the related problems with external NAT devices/layers and IPv4-only FTP.
3649 NAME: ftp_sanitycheck
3652 LOC: Config.Ftp.sanitycheck
3654 For security and data integrity reasons Squid by default performs
3655 sanity checks of the addresses of FTP data connections ensure the
3656 data connection is to the requested server. If you need to allow
3657 FTP connections to servers using another IP address for the data
3658 connection turn this off.
3661 NAME: ftp_telnet_protocol
3664 LOC: Config.Ftp.telnet
3666 The FTP protocol is officially defined to use the telnet protocol
3667 as transport channel for the control connection. However, many
3668 implementations are broken and does not respect this aspect of
3671 If you have trouble accessing files with ASCII code 255 in the
3672 path or similar problems involving this ASCII code you can
3673 try setting this directive to off. If that helps, report to the
3674 operator of the FTP server in question that their FTP server
3675 is broken and does not follow the FTP standard.
3679 OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
3680 -----------------------------------------------------------------------------
3685 DEFAULT: @DEFAULT_DISKD@
3686 LOC: Config.Program.diskd
3688 Specify the location of the diskd executable.
3689 Note this is only useful if you have compiled in
3690 diskd as one of the store io modules.
3693 NAME: unlinkd_program
3696 DEFAULT: @DEFAULT_UNLINKD@
3697 LOC: Config.Program.unlinkd
3699 Specify the location of the executable for file deletion process.
3702 NAME: pinger_program
3704 DEFAULT: @DEFAULT_PINGER@
3705 LOC: Config.pinger.program
3708 Specify the location of the executable for the pinger process.
3714 LOC: Config.pinger.enable
3717 Control whether the pinger is active at run-time.
3718 Enables turning ICMP pinger on and off with a simple
3719 squid -k reconfigure.
3724 OPTIONS FOR URL REWRITING
3725 -----------------------------------------------------------------------------
3728 NAME: url_rewrite_program redirect_program
3730 LOC: Config.Program.redirect
3733 Specify the location of the executable URL rewriter to use.
3734 Since they can perform almost any function there isn't one included.
3736 For each requested URL, the rewriter will receive on line with the format
3738 URL <SP> client_ip "/" fqdn <SP> user <SP> method [<SP> kvpairs]<NL>
3740 In the future, the rewriter interface will be extended with
3741 key=value pairs ("kvpairs" shown above). Rewriter programs
3742 should be prepared to receive and possibly ignore additional
3743 whitespace-separated tokens on each input line.
3745 And the rewriter may return a rewritten URL. The other components of
3746 the request line does not need to be returned (ignored if they are).
3748 The rewriter can also indicate that a client-side redirect should
3749 be performed to the new URL. This is done by prefixing the returned
3750 URL with "301:" (moved permanently) or 302: (moved temporarily), etc.
3752 By default, a URL rewriter is not used.
3755 NAME: url_rewrite_children redirect_children
3756 TYPE: HelperChildConfig
3757 DEFAULT: 20 startup=0 idle=1 concurrency=0
3758 LOC: Config.redirectChildren
3760 The maximum number of redirector processes to spawn. If you limit
3761 it too few Squid will have to wait for them to process a backlog of
3762 URLs, slowing it down. If you allow too many they will use RAM
3763 and other system resources noticably.
3765 The startup= and idle= options allow some measure of skew in your
3770 Sets a minimum of how many processes are to be spawned when Squid
3771 starts or reconfigures. When set to zero the first request will
3772 cause spawning of the first child process to handle it.
3774 Starting too few will cause an initial slowdown in traffic as Squid
3775 attempts to simultaneously spawn enough processes to cope.
3779 Sets a minimum of how many processes Squid is to try and keep available
3780 at all times. When traffic begins to rise above what the existing
3781 processes can handle this many more will be spawned up to the maximum
3782 configured. A minimum setting of 1 is required.
3786 The number of requests each redirector helper can handle in
3787 parallel. Defaults to 0 which indicates the redirector
3788 is a old-style single threaded redirector.
3790 When this directive is set to a value >= 1 then the protocol
3791 used to communicate with the helper is modified to include
3792 a request ID in front of the request/response. The request
3793 ID from the request must be echoed back with the response
3797 NAME: url_rewrite_host_header redirect_rewrites_host_header
3800 LOC: Config.onoff.redir_rewrites_host
3802 To preserve same-origin security policies in browsers and
3803 prevent Host: header forgery by redirectors Squid rewrites
3804 any Host: header in redirected requests.
3806 If you are running an accelerator this may not be a wanted
3807 effect of a redirector. This directive enables you disable
3808 Host: alteration in reverse-proxy traffic.
3810 WARNING: Entries are cached on the result of the URL rewriting
3811 process, so be careful if you have domain-virtual hosts.
3813 WARNING: Squid and other software verifies the URL and Host
3814 are matching, so be careful not to relay through other proxies
3815 or inspecting firewalls with this disabled.
3818 NAME: url_rewrite_access redirector_access
3821 LOC: Config.accessList.redirector
3823 If defined, this access list specifies which requests are
3824 sent to the redirector processes. By default all requests
3827 This clause supports both fast and slow acl types.
3828 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
3831 NAME: url_rewrite_bypass redirector_bypass
3833 LOC: Config.onoff.redirector_bypass
3836 When this is 'on', a request will not go through the
3837 redirector if all redirectors are busy. If this is 'off'
3838 and the redirector queue grows too large, Squid will exit
3839 with a FATAL error and ask you to increase the number of
3840 redirectors. You should only enable this if the redirectors
3841 are not critical to your caching system. If you use
3842 redirectors for access control, and you enable this option,
3843 users may have access to pages they should not
3844 be allowed to request.
3848 OPTIONS FOR TUNING THE CACHE
3849 -----------------------------------------------------------------------------
3852 NAME: cache no_cache
3855 LOC: Config.accessList.noCache
3857 A list of ACL elements which, if matched and denied, cause the request to
3858 not be satisfied from the cache and the reply to not be cached.
3859 In other words, use this to force certain objects to never be cached.
3861 You must use the words 'allow' or 'deny' to indicate whether items
3862 matching the ACL should be allowed or denied into the cache.
3864 Default is to allow all to be cached.
3866 This clause supports both fast and slow acl types.
3867 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
3873 LOC: Config.maxStale
3876 This option puts an upper limit on how stale content Squid
3877 will serve from the cache if cache validation fails.
3878 Can be overriden by the refresh_pattern max-stale option.
3881 NAME: refresh_pattern
3882 TYPE: refreshpattern
3886 usage: refresh_pattern [-i] regex min percent max [options]
3888 By default, regular expressions are CASE-SENSITIVE. To make
3889 them case-insensitive, use the -i option.
3891 'Min' is the time (in minutes) an object without an explicit
3892 expiry time should be considered fresh. The recommended
3893 value is 0, any higher values may cause dynamic applications
3894 to be erroneously cached unless the application designer
3895 has taken the appropriate actions.
3897 'Percent' is a percentage of the objects age (time since last
3898 modification age) an object without explicit expiry time
3899 will be considered fresh.
3901 'Max' is an upper limit on how long objects without an explicit
3902 expiry time will be considered fresh.
3904 options: override-expire
3910 ignore-must-revalidate
3917 override-expire enforces min age even if the server
3918 sent an explicit expiry time (e.g., with the
3919 Expires: header or Cache-Control: max-age). Doing this
3920 VIOLATES the HTTP standard. Enabling this feature
3921 could make you liable for problems which it causes.
3923 Note: override-expire does not enforce staleness - it only extends
3924 freshness / min. If the server returns a Expires time which
3925 is longer than your max time, Squid will still consider
3926 the object fresh for that period of time.
3928 override-lastmod enforces min age even on objects
3929 that were modified recently.
3931 reload-into-ims changes client no-cache or ``reload''
3932 to If-Modified-Since requests. Doing this VIOLATES the
3933 HTTP standard. Enabling this feature could make you
3934 liable for problems which it causes.
3936 ignore-reload ignores a client no-cache or ``reload''
3937 header. Doing this VIOLATES the HTTP standard. Enabling
3938 this feature could make you liable for problems which
3941 ignore-no-cache ignores any ``Pragma: no-cache'' and
3942 ``Cache-control: no-cache'' headers received from a server.
3943 The HTTP RFC never allows the use of this (Pragma) header
3944 from a server, only a client, though plenty of servers
3947 ignore-no-store ignores any ``Cache-control: no-store''
3948 headers received from a server. Doing this VIOLATES
3949 the HTTP standard. Enabling this feature could make you
3950 liable for problems which it causes.
3952 ignore-must-revalidate ignores any ``Cache-Control: must-revalidate``
3953 headers received from a server. Doing this VIOLATES
3954 the HTTP standard. Enabling this feature could make you
3955 liable for problems which it causes.
3957 ignore-private ignores any ``Cache-control: private''
3958 headers received from a server. Doing this VIOLATES
3959 the HTTP standard. Enabling this feature could make you
3960 liable for problems which it causes.
3962 ignore-auth caches responses to requests with authorization,
3963 as if the originserver had sent ``Cache-control: public''
3964 in the response header. Doing this VIOLATES the HTTP standard.
3965 Enabling this feature could make you liable for problems which
3968 refresh-ims causes squid to contact the origin server
3969 when a client issues an If-Modified-Since request. This
3970 ensures that the client will receive an updated version
3971 if one is available.
3973 store-stale stores responses even if they don't have explicit
3974 freshness or a validator (i.e., Last-Modified or an ETag)
3975 present, or if they're already stale. By default, Squid will
3976 not cache such responses because they usually can't be
3977 reused. Note that such responses will be stale by default.
3979 max-stale=NN provide a maximum staleness factor. Squid won't
3980 serve objects more stale than this even if it failed to
3981 validate the object. Default: use the max_stale global limit.
3983 Basically a cached object is:
3985 FRESH if expires < now, else STALE
3987 FRESH if lm-factor < percent, else STALE
3991 The refresh_pattern lines are checked in the order listed here.
3992 The first entry which matches is used. If none of the entries
3993 match the default will be used.
3995 Note, you must uncomment all the default lines if you want
3996 to change one. The default setting is only active if none is
4001 # Add any of your own refresh_pattern entries above these.
4002 refresh_pattern ^ftp: 1440 20% 10080
4003 refresh_pattern ^gopher: 1440 0% 1440
4004 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0
4005 refresh_pattern . 0 20% 4320
4009 NAME: quick_abort_min
4013 LOC: Config.quickAbort.min
4016 NAME: quick_abort_max
4020 LOC: Config.quickAbort.max
4023 NAME: quick_abort_pct
4027 LOC: Config.quickAbort.pct
4029 The cache by default continues downloading aborted requests
4030 which are almost completed (less than 16 KB remaining). This
4031 may be undesirable on slow (e.g. SLIP) links and/or very busy
4032 caches. Impatient users may tie up file descriptors and
4033 bandwidth by repeatedly requesting and immediately aborting
4036 When the user aborts a request, Squid will check the
4037 quick_abort values to the amount of data transfered until
4040 If the transfer has less than 'quick_abort_min' KB remaining,
4041 it will finish the retrieval.
4043 If the transfer has more than 'quick_abort_max' KB remaining,
4044 it will abort the retrieval.
4046 If more than 'quick_abort_pct' of the transfer has completed,
4047 it will finish the retrieval.
4049 If you do not want any retrieval to continue after the client
4050 has aborted, set both 'quick_abort_min' and 'quick_abort_max'
4053 If you want retrievals to always continue if they are being
4054 cached set 'quick_abort_min' to '-1 KB'.
4057 NAME: read_ahead_gap
4058 COMMENT: buffer-size
4060 LOC: Config.readAheadGap
4063 The amount of data the cache will buffer ahead of what has been
4064 sent to the client when retrieving an object from another server.
4068 IFDEF: USE_HTTP_VIOLATIONS
4071 LOC: Config.negativeTtl
4074 Set the Default Time-to-Live (TTL) for failed requests.
4075 Certain types of failures (such as "connection refused" and
4076 "404 Not Found") are able to be negatively-cached for a short time.
4077 Modern web servers should provide Expires: header, however if they
4078 do not this can provide a minimum TTL.
4079 The default is not to cache errors with unknown expiry details.
4081 Note that this is different from negative caching of DNS lookups.
4083 WARNING: Doing this VIOLATES the HTTP standard. Enabling
4084 this feature could make you liable for problems which it
4088 NAME: positive_dns_ttl
4091 LOC: Config.positiveDnsTtl
4094 Upper limit on how long Squid will cache positive DNS responses.
4095 Default is 6 hours (360 minutes). This directive must be set
4096 larger than negative_dns_ttl.
4099 NAME: negative_dns_ttl
4102 LOC: Config.negativeDnsTtl
4105 Time-to-Live (TTL) for negative caching of failed DNS lookups.
4106 This also sets the lower cache limit on positive lookups.
4107 Minimum value is 1 second, and it is not recommendable to go
4108 much below 10 seconds.
4111 NAME: range_offset_limit
4112 COMMENT: size [acl acl...]
4114 LOC: Config.rangeOffsetLimit
4117 usage: (size) [units] [[!]aclname]
4119 Sets an upper limit on how far (number of bytes) into the file
4120 a Range request may be to cause Squid to prefetch the whole file.
4121 If beyond this limit, Squid forwards the Range request as it is and
4122 the result is NOT cached.
4124 This is to stop a far ahead range request (lets say start at 17MB)
4125 from making Squid fetch the whole object up to that point before
4126 sending anything to the client.
4128 Multiple range_offset_limit lines may be specified, and they will
4129 be searched from top to bottom on each request until a match is found.
4130 The first match found will be used. If no line matches a request, the
4131 default limit of 0 bytes will be used.
4133 'size' is the limit specified as a number of units.
4135 'units' specifies whether to use bytes, KB, MB, etc.
4136 If no units are specified bytes are assumed.
4138 A size of 0 causes Squid to never fetch more than the
4139 client requested. (default)
4141 A size of 'none' causes Squid to always fetch the object from the
4142 beginning so it may cache the result. (2.0 style)
4144 'aclname' is the name of a defined ACL.
4146 NP: Using 'none' as the byte value here will override any quick_abort settings
4147 that may otherwise apply to the range request. The range request will
4148 be fully fetched from start to finish regardless of the client
4149 actions. This affects bandwidth usage.
4152 NAME: minimum_expiry_time
4155 LOC: Config.minimum_expiry_time
4158 The minimum caching time according to (Expires - Date)
4159 Headers Squid honors if the object can't be revalidated
4160 defaults to 60 seconds. In reverse proxy environments it
4161 might be desirable to honor shorter object lifetimes. It
4162 is most likely better to make your server return a
4163 meaningful Last-Modified header however. In ESI environments
4164 where page fragments often have short lifetimes, this will
4165 often be best set to 0.
4168 NAME: store_avg_object_size
4172 LOC: Config.Store.avgObjectSize
4174 Average object size, used to estimate number of objects your
4175 cache can hold. The default is 13 KB.
4178 NAME: store_objects_per_bucket
4181 LOC: Config.Store.objectsPerBucket
4183 Target number of objects per bucket in the store hash table.
4184 Lowering this value increases the total number of buckets and
4185 also the storage maintenance rate. The default is 20.
4190 -----------------------------------------------------------------------------
4193 NAME: request_header_max_size
4197 LOC: Config.maxRequestHeaderSize
4199 This specifies the maximum size for HTTP headers in a request.
4200 Request headers are usually relatively small (about 512 bytes).
4201 Placing a limit on the request header size will catch certain
4202 bugs (for example with persistent connections) and possibly
4203 buffer-overflow or denial-of-service attacks.
4206 NAME: reply_header_max_size
4210 LOC: Config.maxReplyHeaderSize
4212 This specifies the maximum size for HTTP headers in a reply.
4213 Reply headers are usually relatively small (about 512 bytes).
4214 Placing a limit on the reply header size will catch certain
4215 bugs (for example with persistent connections) and possibly
4216 buffer-overflow or denial-of-service attacks.
4219 NAME: request_body_max_size
4223 LOC: Config.maxRequestBodySize
4225 This specifies the maximum size for an HTTP request body.
4226 In other words, the maximum size of a PUT/POST request.
4227 A user who attempts to send a request with a body larger
4228 than this limit receives an "Invalid Request" error message.
4229 If you set this parameter to a zero (the default), there will
4230 be no limit imposed.
4233 NAME: client_request_buffer_max_size
4237 LOC: Config.maxRequestBufferSize
4239 This specifies the maximum buffer size of a client request.
4240 It prevents squid eating too much memory when somebody uploads
4244 NAME: chunked_request_body_max_size
4248 LOC: Config.maxChunkedRequestBodySize
4250 A broken or confused HTTP/1.1 client may send a chunked HTTP
4251 request to Squid. Squid does not have full support for that
4252 feature yet. To cope with such requests, Squid buffers the
4253 entire request and then dechunks request body to create a
4254 plain HTTP/1.0 request with a known content length. The plain
4255 request is then used by the rest of Squid code as usual.
4257 The option value specifies the maximum size of the buffer used
4258 to hold the request before the conversion. If the chunked
4259 request size exceeds the specified limit, the conversion
4260 fails, and the client receives an "unsupported request" error,
4261 as if dechunking was disabled.
4263 Dechunking is enabled by default. To disable conversion of
4264 chunked requests, set the maximum to zero.
4266 Request dechunking feature and this option in particular are a
4267 temporary hack. When chunking requests and responses are fully
4268 supported, there will be no need to buffer a chunked request.
4272 IFDEF: USE_HTTP_VIOLATIONS
4275 LOC: Config.accessList.brokenPosts
4277 A list of ACL elements which, if matched, causes Squid to send
4278 an extra CRLF pair after the body of a PUT/POST request.
4280 Some HTTP servers has broken implementations of PUT/POST,
4281 and rely on an extra CRLF pair sent by some WWW clients.
4283 Quote from RFC2616 section 4.1 on this matter:
4285 Note: certain buggy HTTP/1.0 client implementations generate an
4286 extra CRLF's after a POST request. To restate what is explicitly
4287 forbidden by the BNF, an HTTP/1.1 client must not preface or follow
4288 a request with an extra CRLF.
4290 This clause only supports fast acl types.
4291 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4294 acl buggy_server url_regex ^http://....
4295 broken_posts allow buggy_server
4298 NAME: adaptation_uses_indirect_client icap_uses_indirect_client
4301 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_ADAPTATION
4303 LOC: Adaptation::Config::use_indirect_client
4305 Controls whether the indirect client IP address (instead of the direct
4306 client IP address) is passed to adaptation services.
4308 See also: follow_x_forwarded_for adaptation_send_client_ip
4312 IFDEF: USE_HTTP_VIOLATIONS
4316 LOC: Config.onoff.via
4318 If set (default), Squid will include a Via header in requests and
4319 replies as required by RFC2616.
4325 LOC: Config.onoff.ie_refresh
4328 Microsoft Internet Explorer up until version 5.5 Service
4329 Pack 1 has an issue with transparent proxies, wherein it
4330 is impossible to force a refresh. Turning this on provides
4331 a partial fix to the problem, by causing all IMS-REFRESH
4332 requests from older IE versions to check the origin server
4333 for fresh content. This reduces hit ratio by some amount
4334 (~10% in my experience), but allows users to actually get
4335 fresh content when they want it. Note because Squid
4336 cannot tell if the user is using 5.5 or 5.5SP1, the behavior
4337 of 5.5 is unchanged from old versions of Squid (i.e. a
4338 forced refresh is impossible). Newer versions of IE will,
4339 hopefully, continue to have the new behavior and will be
4340 handled based on that assumption. This option defaults to
4341 the old Squid behavior, which is better for hit ratios but
4342 worse for clients using IE, if they need to be able to
4343 force fresh content.
4346 NAME: vary_ignore_expire
4349 LOC: Config.onoff.vary_ignore_expire
4352 Many HTTP servers supporting Vary gives such objects
4353 immediate expiry time with no cache-control header
4354 when requested by a HTTP/1.0 client. This option
4355 enables Squid to ignore such expiry times until
4356 HTTP/1.1 is fully implemented.
4358 WARNING: If turned on this may eventually cause some
4359 varying objects not intended for caching to get cached.
4362 NAME: request_entities
4364 LOC: Config.onoff.request_entities
4367 Squid defaults to deny GET and HEAD requests with request entities,
4368 as the meaning of such requests are undefined in the HTTP standard
4369 even if not explicitly forbidden.
4371 Set this directive to on if you have clients which insists
4372 on sending request entities in GET or HEAD requests. But be warned
4373 that there is server software (both proxies and web servers) which
4374 can fail to properly process this kind of request which may make you
4375 vulnerable to cache pollution attacks if enabled.
4378 NAME: request_header_access
4379 IFDEF: USE_HTTP_VIOLATIONS
4380 TYPE: http_header_access[]
4381 LOC: Config.request_header_access
4384 Usage: request_header_access header_name allow|deny [!]aclname ...
4386 WARNING: Doing this VIOLATES the HTTP standard. Enabling
4387 this feature could make you liable for problems which it
4390 This option replaces the old 'anonymize_headers' and the
4391 older 'http_anonymizer' option with something that is much
4392 more configurable. This new method creates a list of ACLs
4393 for each header, allowing you very fine-tuned header
4396 This option only applies to request headers, i.e., from the
4397 client to the server.
4399 You can only specify known headers for the header name.
4400 Other headers are reclassified as 'Other'. You can also
4401 refer to all the headers with 'All'.
4403 For example, to achieve the same behavior as the old
4404 'http_anonymizer standard' option, you should use:
4406 request_header_access From deny all
4407 request_header_access Referer deny all
4408 request_header_access Server deny all
4409 request_header_access User-Agent deny all
4410 request_header_access WWW-Authenticate deny all
4411 request_header_access Link deny all
4413 Or, to reproduce the old 'http_anonymizer paranoid' feature
4416 request_header_access Allow allow all
4417 request_header_access Authorization allow all
4418 request_header_access WWW-Authenticate allow all
4419 request_header_access Proxy-Authorization allow all
4420 request_header_access Proxy-Authenticate allow all
4421 request_header_access Cache-Control allow all
4422 request_header_access Content-Encoding allow all
4423 request_header_access Content-Length allow all
4424 request_header_access Content-Type allow all
4425 request_header_access Date allow all
4426 request_header_access Expires allow all
4427 request_header_access Host allow all
4428 request_header_access If-Modified-Since allow all
4429 request_header_access Last-Modified allow all
4430 request_header_access Location allow all
4431 request_header_access Pragma allow all
4432 request_header_access Accept allow all
4433 request_header_access Accept-Charset allow all
4434 request_header_access Accept-Encoding allow all
4435 request_header_access Accept-Language allow all
4436 request_header_access Content-Language allow all
4437 request_header_access Mime-Version allow all
4438 request_header_access Retry-After allow all
4439 request_header_access Title allow all
4440 request_header_access Connection allow all
4441 request_header_access All deny all
4443 although many of those are HTTP reply headers, and so should be
4444 controlled with the reply_header_access directive.
4446 By default, all headers are allowed (no anonymizing is
4450 NAME: reply_header_access
4451 IFDEF: USE_HTTP_VIOLATIONS
4452 TYPE: http_header_access[]
4453 LOC: Config.reply_header_access
4456 Usage: reply_header_access header_name allow|deny [!]aclname ...
4458 WARNING: Doing this VIOLATES the HTTP standard. Enabling
4459 this feature could make you liable for problems which it
4462 This option only applies to reply headers, i.e., from the
4463 server to the client.
4465 This is the same as request_header_access, but in the other
4468 This option replaces the old 'anonymize_headers' and the
4469 older 'http_anonymizer' option with something that is much
4470 more configurable. This new method creates a list of ACLs
4471 for each header, allowing you very fine-tuned header
4474 You can only specify known headers for the header name.
4475 Other headers are reclassified as 'Other'. You can also
4476 refer to all the headers with 'All'.
4478 For example, to achieve the same behavior as the old
4479 'http_anonymizer standard' option, you should use:
4481 reply_header_access From deny all
4482 reply_header_access Referer deny all
4483 reply_header_access Server deny all
4484 reply_header_access User-Agent deny all
4485 reply_header_access WWW-Authenticate deny all
4486 reply_header_access Link deny all
4488 Or, to reproduce the old 'http_anonymizer paranoid' feature
4491 reply_header_access Allow allow all
4492 reply_header_access Authorization allow all
4493 reply_header_access WWW-Authenticate allow all
4494 reply_header_access Proxy-Authorization allow all
4495 reply_header_access Proxy-Authenticate allow all
4496 reply_header_access Cache-Control allow all
4497 reply_header_access Content-Encoding allow all
4498 reply_header_access Content-Length allow all
4499 reply_header_access Content-Type allow all
4500 reply_header_access Date allow all
4501 reply_header_access Expires allow all
4502 reply_header_access Host allow all
4503 reply_header_access If-Modified-Since allow all
4504 reply_header_access Last-Modified allow all
4505 reply_header_access Location allow all
4506 reply_header_access Pragma allow all
4507 reply_header_access Accept allow all
4508 reply_header_access Accept-Charset allow all
4509 reply_header_access Accept-Encoding allow all
4510 reply_header_access Accept-Language allow all
4511 reply_header_access Content-Language allow all
4512 reply_header_access Mime-Version allow all
4513 reply_header_access Retry-After allow all
4514 reply_header_access Title allow all
4515 reply_header_access Connection allow all
4516 reply_header_access All deny all
4518 although the HTTP request headers won't be usefully controlled
4519 by this directive -- see request_header_access for details.
4521 By default, all headers are allowed (no anonymizing is
4525 NAME: request_header_replace header_replace
4526 IFDEF: USE_HTTP_VIOLATIONS
4527 TYPE: http_header_replace[]
4528 LOC: Config.request_header_access
4531 Usage: request_header_replace header_name message
4532 Example: request_header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
4534 This option allows you to change the contents of headers
4535 denied with request_header_access above, by replacing them
4536 with some fixed string. This replaces the old fake_user_agent
4539 This only applies to request headers, not reply headers.
4541 By default, headers are removed if denied.
4544 NAME: reply_header_replace
4545 IFDEF: USE_HTTP_VIOLATIONS
4546 TYPE: http_header_replace[]
4547 LOC: Config.reply_header_access
4550 Usage: reply_header_replace header_name message
4551 Example: reply_header_replace Server Foo/1.0
4553 This option allows you to change the contents of headers
4554 denied with reply_header_access above, by replacing them
4555 with some fixed string.
4557 This only applies to reply headers, not request headers.
4559 By default, headers are removed if denied.
4562 NAME: relaxed_header_parser
4563 COMMENT: on|off|warn
4565 LOC: Config.onoff.relaxed_header_parser
4568 In the default "on" setting Squid accepts certain forms
4569 of non-compliant HTTP messages where it is unambiguous
4570 what the sending application intended even if the message
4571 is not correctly formatted. The messages is then normalized
4572 to the correct form when forwarded by Squid.
4574 If set to "warn" then a warning will be emitted in cache.log
4575 each time such HTTP error is encountered.
4577 If set to "off" then such HTTP errors will cause the request
4578 or response to be rejected.
4583 -----------------------------------------------------------------------------
4586 NAME: forward_timeout
4589 LOC: Config.Timeout.forward
4592 This parameter specifies how long Squid should at most attempt in
4593 finding a forwarding path for the request before giving up.
4596 NAME: connect_timeout
4599 LOC: Config.Timeout.connect
4602 This parameter specifies how long to wait for the TCP connect to
4603 the requested server or peer to complete before Squid should
4604 attempt to find another path where to forward the request.
4607 NAME: peer_connect_timeout
4610 LOC: Config.Timeout.peer_connect
4613 This parameter specifies how long to wait for a pending TCP
4614 connection to a peer cache. The default is 30 seconds. You
4615 may also set different timeout values for individual neighbors
4616 with the 'connect-timeout' option on a 'cache_peer' line.
4622 LOC: Config.Timeout.read
4625 The read_timeout is applied on server-side connections. After
4626 each successful read(), the timeout will be extended by this
4627 amount. If no data is read again after this amount of time,
4628 the request is aborted and logged with ERR_READ_TIMEOUT. The
4629 default is 15 minutes.
4635 LOC: Config.Timeout.write
4638 This timeout is tracked for all connections that have data
4639 available for writing and are waiting for the socket to become
4640 ready. After each successful write, the timeout is extended by
4641 the configured amount. If Squid has data to write but the
4642 connection is not ready for the configured duration, the
4643 transaction associated with the connection is terminated. The
4644 default is 15 minutes.
4647 NAME: request_timeout
4649 LOC: Config.Timeout.request
4652 How long to wait for an HTTP request after initial
4653 connection establishment.
4656 NAME: persistent_request_timeout
4658 LOC: Config.Timeout.persistent_request
4661 How long to wait for the next HTTP request on a persistent
4662 connection after the previous request completes.
4665 NAME: client_lifetime
4668 LOC: Config.Timeout.lifetime
4671 The maximum amount of time a client (browser) is allowed to
4672 remain connected to the cache process. This protects the Cache
4673 from having a lot of sockets (and hence file descriptors) tied up
4674 in a CLOSE_WAIT state from remote clients that go away without
4675 properly shutting down (either because of a network failure or
4676 because of a poor client implementation). The default is one
4679 NOTE: The default value is intended to be much larger than any
4680 client would ever need to be connected to your cache. You
4681 should probably change client_lifetime only as a last resort.
4682 If you seem to have many client connections tying up
4683 filedescriptors, we recommend first tuning the read_timeout,
4684 request_timeout, persistent_request_timeout and quick_abort values.
4687 NAME: half_closed_clients
4689 LOC: Config.onoff.half_closed_clients
4692 Some clients may shutdown the sending side of their TCP
4693 connections, while leaving their receiving sides open. Sometimes,
4694 Squid can not tell the difference between a half-closed and a
4695 fully-closed TCP connection.
4697 By default, Squid will immediately close client connections when
4698 read(2) returns "no more data to read."
4700 Change this option to 'on' and Squid will keep open connections
4701 until a read(2) or write(2) on the socket returns an error.
4702 This may show some benefits for reverse proxies. But if not
4703 it is recommended to leave OFF.
4708 LOC: Config.Timeout.pconn
4711 Timeout for idle persistent connections to servers and other
4718 LOC: Ident::TheConfig.timeout
4721 Maximum time to wait for IDENT lookups to complete.
4723 If this is too high, and you enabled IDENT lookups from untrusted
4724 users, you might be susceptible to denial-of-service by having
4725 many ident requests going at once.
4728 NAME: shutdown_lifetime
4731 LOC: Config.shutdownLifetime
4734 When SIGTERM or SIGHUP is received, the cache is put into
4735 "shutdown pending" mode until all active sockets are closed.
4736 This value is the lifetime to set for all open descriptors
4737 during shutdown mode. Any active clients after this many
4738 seconds will receive a 'timeout' message.
4742 ADMINISTRATIVE PARAMETERS
4743 -----------------------------------------------------------------------------
4749 LOC: Config.adminEmail
4751 Email-address of local cache manager who will receive
4752 mail if the cache dies. The default is "webmaster."
4758 LOC: Config.EmailFrom
4760 From: email-address for mail sent when the cache dies.
4761 The default is to use 'appname@unique_hostname'.
4762 Default appname value is "squid", can be changed into
4763 src/globals.h before building squid.
4769 LOC: Config.EmailProgram
4771 Email program used to send mail if the cache dies.
4772 The default is "mail". The specified program must comply
4773 with the standard Unix mail syntax:
4774 mail-program recipient < mailfile
4776 Optional command line options can be specified.
4779 NAME: cache_effective_user
4781 DEFAULT: @DEFAULT_CACHE_EFFECTIVE_USER@
4782 LOC: Config.effectiveUser
4784 If you start Squid as root, it will change its effective/real
4785 UID/GID to the user specified below. The default is to change
4786 to UID of @DEFAULT_CACHE_EFFECTIVE_USER@.
4787 see also; cache_effective_group
4790 NAME: cache_effective_group
4793 LOC: Config.effectiveGroup
4795 Squid sets the GID to the effective user's default group ID
4796 (taken from the password file) and supplementary group list
4797 from the groups membership.
4799 If you want Squid to run with a specific GID regardless of
4800 the group memberships of the effective user then set this
4801 to the group (or GID) you want Squid to run as. When set
4802 all other group privileges of the effective user are ignored
4803 and only this GID is effective. If Squid is not started as
4804 root the user starting Squid MUST be member of the specified
4807 This option is not recommended by the Squid Team.
4808 Our preference is for administrators to configure a secure
4809 user account for squid with UID/GID matching system policies.
4812 NAME: httpd_suppress_version_string
4816 LOC: Config.onoff.httpd_suppress_version_string
4818 Suppress Squid version string info in HTTP headers and HTML error pages.
4821 NAME: visible_hostname
4823 LOC: Config.visibleHostname
4826 If you want to present a special hostname in error messages, etc,
4827 define this. Otherwise, the return value of gethostname()
4828 will be used. If you have multiple caches in a cluster and
4829 get errors about IP-forwarding you must set them to have individual
4830 names with this setting.
4833 NAME: unique_hostname
4835 LOC: Config.uniqueHostname
4838 If you want to have multiple machines with the same
4839 'visible_hostname' you must give each machine a different
4840 'unique_hostname' so forwarding loops can be detected.
4843 NAME: hostname_aliases
4845 LOC: Config.hostnameAliases
4848 A list of other DNS names your cache has.
4856 Minimum umask which should be enforced while the proxy
4857 is running, in addition to the umask set at startup.
4859 For a traditional octal representation of umasks, start
4864 OPTIONS FOR THE CACHE REGISTRATION SERVICE
4865 -----------------------------------------------------------------------------
4867 This section contains parameters for the (optional) cache
4868 announcement service. This service is provided to help
4869 cache administrators locate one another in order to join or
4870 create cache hierarchies.
4872 An 'announcement' message is sent (via UDP) to the registration
4873 service by Squid. By default, the announcement message is NOT
4874 SENT unless you enable it with 'announce_period' below.
4876 The announcement message includes your hostname, plus the
4877 following information from this configuration file:
4883 All current information is processed regularly and made
4884 available on the Web at http://www.ircache.net/Cache/Tracker/.
4887 NAME: announce_period
4889 LOC: Config.Announce.period
4892 This is how frequently to send cache announcements. The
4893 default is `0' which disables sending the announcement
4896 To enable announcing your cache, just set an announce period.
4899 announce_period 1 day
4904 DEFAULT: tracker.ircache.net
4905 LOC: Config.Announce.host
4911 LOC: Config.Announce.file
4917 LOC: Config.Announce.port
4919 announce_host and announce_port set the hostname and port
4920 number where the registration message will be sent.
4922 Hostname will default to 'tracker.ircache.net' and port will
4923 default default to 3131. If the 'filename' argument is given,
4924 the contents of that file will be included in the announce
4929 HTTPD-ACCELERATOR OPTIONS
4930 -----------------------------------------------------------------------------
4933 NAME: httpd_accel_surrogate_id
4936 LOC: Config.Accel.surrogate_id
4938 Surrogates (http://www.esi.org/architecture_spec_1.0.html)
4939 need an identification token to allow control targeting. Because
4940 a farm of surrogates may all perform the same tasks, they may share
4941 an identification token.
4943 The default ID is the visible_hostname
4946 NAME: http_accel_surrogate_remote
4950 LOC: Config.onoff.surrogate_is_remote
4952 Remote surrogates (such as those in a CDN) honour Surrogate-Control: no-store-remote.
4953 Set this to on to have squid behave as a remote surrogate.
4957 IFDEF: USE_SQUID_ESI
4958 COMMENT: libxml2|expat|custom
4960 LOC: ESIParser::Type
4963 ESI markup is not strictly XML compatible. The custom ESI parser
4964 will give higher performance, but cannot handle non ASCII character
4969 DELAY POOL PARAMETERS
4970 -----------------------------------------------------------------------------
4974 TYPE: delay_pool_count
4976 IFDEF: USE_DELAY_POOLS
4979 This represents the number of delay pools to be used. For example,
4980 if you have one class 2 delay pool and one class 3 delays pool, you
4981 have a total of 2 delay pools.
4985 TYPE: delay_pool_class
4987 IFDEF: USE_DELAY_POOLS
4990 This defines the class of each delay pool. There must be exactly one
4991 delay_class line for each delay pool. For example, to define two
4992 delay pools, one of class 2 and one of class 3, the settings above
4996 delay_pools 4 # 4 delay pools
4997 delay_class 1 2 # pool 1 is a class 2 pool
4998 delay_class 2 3 # pool 2 is a class 3 pool
4999 delay_class 3 4 # pool 3 is a class 4 pool
5000 delay_class 4 5 # pool 4 is a class 5 pool
5002 The delay pool classes are:
5004 class 1 Everything is limited by a single aggregate
5007 class 2 Everything is limited by a single aggregate
5008 bucket as well as an "individual" bucket chosen
5009 from bits 25 through 32 of the IPv4 address.
5011 class 3 Everything is limited by a single aggregate
5012 bucket as well as a "network" bucket chosen
5013 from bits 17 through 24 of the IP address and a
5014 "individual" bucket chosen from bits 17 through
5015 32 of the IPv4 address.
5017 class 4 Everything in a class 3 delay pool, with an
5018 additional limit on a per user basis. This
5019 only takes effect if the username is established
5020 in advance - by forcing authentication in your
5023 class 5 Requests are grouped according their tag (see
5024 external_acl's tag= reply).
5027 Each pool also requires a delay_parameters directive to configure the pool size
5028 and speed limits used whenever the pool is applied to a request. Along with
5029 a set of delay_access directives to determine when it is used.
5031 NOTE: If an IP address is a.b.c.d
5032 -> bits 25 through 32 are "d"
5033 -> bits 17 through 24 are "c"
5034 -> bits 17 through 32 are "c * 256 + d"
5036 NOTE-2: Due to the use of bitmasks in class 2,3,4 pools they only apply to
5037 IPv4 traffic. Class 1 and 5 pools may be used with IPv6 traffic.
5041 TYPE: delay_pool_access
5043 IFDEF: USE_DELAY_POOLS
5046 This is used to determine which delay pool a request falls into.
5048 delay_access is sorted per pool and the matching starts with pool 1,
5049 then pool 2, ..., and finally pool N. The first delay pool where the
5050 request is allowed is selected for the request. If it does not allow
5051 the request to any pool then the request is not delayed (default).
5053 For example, if you want some_big_clients in delay
5054 pool 1 and lotsa_little_clients in delay pool 2:
5057 delay_access 1 allow some_big_clients
5058 delay_access 1 deny all
5059 delay_access 2 allow lotsa_little_clients
5060 delay_access 2 deny all
5061 delay_access 3 allow authenticated_clients
5064 NAME: delay_parameters
5065 TYPE: delay_pool_rates
5067 IFDEF: USE_DELAY_POOLS
5070 This defines the parameters for a delay pool. Each delay pool has
5071 a number of "buckets" associated with it, as explained in the
5072 description of delay_class.
5074 For a class 1 delay pool, the syntax is:
5076 delay_parameters pool aggregate
5078 For a class 2 delay pool:
5080 delay_parameters pool aggregate individual
5082 For a class 3 delay pool:
5084 delay_parameters pool aggregate network individual
5086 For a class 4 delay pool:
5088 delay_parameters pool aggregate network individual user
5090 For a class 5 delay pool:
5092 delay_parameters pool tagrate
5094 The option variables are:
5096 pool a pool number - ie, a number between 1 and the
5097 number specified in delay_pools as used in
5100 aggregate the speed limit parameters for the aggregate bucket
5103 individual the speed limit parameters for the individual
5104 buckets (class 2, 3).
5106 network the speed limit parameters for the network buckets
5109 user the speed limit parameters for the user buckets
5112 tagrate the speed limit parameters for the tag buckets
5115 A pair of delay parameters is written restore/maximum, where restore is
5116 the number of bytes (not bits - modem and network speeds are usually
5117 quoted in bits) per second placed into the bucket, and maximum is the
5118 maximum number of bytes which can be in the bucket at any time.
5120 There must be one delay_parameters line for each delay pool.
5123 For example, if delay pool number 1 is a class 2 delay pool as in the
5124 above example, and is being used to strictly limit each host to 64Kbit/sec
5125 (plus overheads), with no overall limit, the line is:
5127 delay_parameters 1 -1/-1 8000/8000
5129 Note that 8 x 8000 KByte/sec -> 64Kbit/sec.
5131 Note that the figure -1 is used to represent "unlimited".
5134 And, if delay pool number 2 is a class 3 delay pool as in the above
5135 example, and you want to limit it to a total of 256Kbit/sec (strict limit)
5136 with each 8-bit network permitted 64Kbit/sec (strict limit) and each
5137 individual host permitted 4800bit/sec with a bucket maximum size of 64Kbits
5138 to permit a decent web page to be downloaded at a decent speed
5139 (if the network is not being limited due to overuse) but slow down
5140 large downloads more significantly:
5142 delay_parameters 2 32000/32000 8000/8000 600/8000
5144 Note that 8 x 32000 KByte/sec -> 256Kbit/sec.
5145 8 x 8000 KByte/sec -> 64Kbit/sec.
5146 8 x 600 Byte/sec -> 4800bit/sec.
5149 Finally, for a class 4 delay pool as in the example - each user will
5150 be limited to 128Kbits/sec no matter how many workstations they are logged into.:
5152 delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000
5155 NAME: delay_initial_bucket_level
5156 COMMENT: (percent, 0-100)
5159 IFDEF: USE_DELAY_POOLS
5160 LOC: Config.Delay.initial
5162 The initial bucket percentage is used to determine how much is put
5163 in each bucket when squid starts, is reconfigured, or first notices
5164 a host accessing it (in class 2 and class 3, individual hosts and
5165 networks only have buckets associated with them once they have been
5170 CLIENT DELAY POOL PARAMETERS
5171 -----------------------------------------------------------------------------
5174 NAME: client_delay_pools
5175 TYPE: client_delay_pool_count
5177 IFDEF: USE_DELAY_POOLS
5178 LOC: Config.ClientDelay
5180 This option specifies the number of client delay pools used. It must
5181 preceed other client_delay_* options.
5184 client_delay_pools 2
5187 NAME: client_delay_initial_bucket_level
5188 COMMENT: (percent, 0-no_limit)
5191 IFDEF: USE_DELAY_POOLS
5192 LOC: Config.ClientDelay.initial
5194 This option determines the initial bucket size as a percentage of
5195 max_bucket_size from client_delay_parameters. Buckets are created
5196 at the time of the "first" connection from the matching IP. Idle
5197 buckets are periodically deleted up.
5199 You can specify more than 100 percent but note that such "oversized"
5200 buckets are not refilled until their size goes down to max_bucket_size
5201 from client_delay_parameters.
5204 client_delay_initial_bucket_level 50
5207 NAME: client_delay_parameters
5208 TYPE: client_delay_pool_rates
5210 IFDEF: USE_DELAY_POOLS
5211 LOC: Config.ClientDelay
5214 This option configures client-side bandwidth limits using the
5217 client_delay_parameters pool speed_limit max_bucket_size
5219 pool is an integer ID used for client_delay_access matching.
5221 speed_limit is bytes added to the bucket per second.
5223 max_bucket_size is the maximum size of a bucket, enforced after any
5224 speed_limit additions.
5226 Please see the delay_parameters option for more information and
5230 client_delay_parameters 1 1024 2048
5231 client_delay_parameters 2 51200 16384
5234 NAME: client_delay_access
5235 TYPE: client_delay_pool_access
5237 IFDEF: USE_DELAY_POOLS
5238 LOC: Config.ClientDelay
5241 This option determines the client-side delay pool for the
5244 client_delay_access pool_ID allow|deny acl_name
5246 All client_delay_access options are checked in their pool ID
5247 order, starting with pool 1. The first checked pool with allowed
5248 request is selected for the request. If no ACL matches or there
5249 are no client_delay_access options, the request bandwidth is not
5252 The ACL-selected pool is then used to find the
5253 client_delay_parameters for the request. Client-side pools are
5254 not used to aggregate clients. Clients are always aggregated
5255 based on their source IP addresses (one bucket per source IP).
5257 Please see delay_access for more examples.
5260 client_delay_access 1 allow low_rate_network
5261 client_delay_access 2 allow vips_network
5265 WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS
5266 -----------------------------------------------------------------------------
5271 LOC: Config.Wccp.router
5275 Use this option to define your WCCP ``home'' router for
5278 wccp_router supports a single WCCP(v1) router
5280 wccp2_router supports multiple WCCPv2 routers
5282 only one of the two may be used at the same time and defines
5283 which version of WCCP to use.
5287 TYPE: IpAddress_list
5288 LOC: Config.Wccp2.router
5292 Use this option to define your WCCP ``home'' router for
5295 wccp_router supports a single WCCP(v1) router
5297 wccp2_router supports multiple WCCPv2 routers
5299 only one of the two may be used at the same time and defines
5300 which version of WCCP to use.
5305 LOC: Config.Wccp.version
5309 This directive is only relevant if you need to set up WCCP(v1)
5310 to some very old and end-of-life Cisco routers. In all other
5311 setups it must be left unset or at the default setting.
5312 It defines an internal version in the WCCP(v1) protocol,
5313 with version 4 being the officially documented protocol.
5315 According to some users, Cisco IOS 11.2 and earlier only
5316 support WCCP version 3. If you're using that or an earlier
5317 version of IOS, you may need to change this value to 3, otherwise
5318 do not specify this parameter.
5321 NAME: wccp2_rebuild_wait
5323 LOC: Config.Wccp2.rebuildwait
5327 If this is enabled Squid will wait for the cache dir rebuild to finish
5328 before sending the first wccp2 HereIAm packet
5331 NAME: wccp2_forwarding_method
5333 LOC: Config.Wccp2.forwarding_method
5337 WCCP2 allows the setting of forwarding methods between the
5338 router/switch and the cache. Valid values are as follows:
5340 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
5341 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
5343 Currently (as of IOS 12.4) cisco routers only support GRE.
5344 Cisco switches only support the L2 redirect assignment method.
5347 NAME: wccp2_return_method
5349 LOC: Config.Wccp2.return_method
5353 WCCP2 allows the setting of return methods between the
5354 router/switch and the cache for packets that the cache
5355 decides not to handle. Valid values are as follows:
5357 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
5358 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
5360 Currently (as of IOS 12.4) cisco routers only support GRE.
5361 Cisco switches only support the L2 redirect assignment.
5363 If the "ip wccp redirect exclude in" command has been
5364 enabled on the cache interface, then it is still safe for
5365 the proxy server to use a l2 redirect method even if this
5366 option is set to GRE.
5369 NAME: wccp2_assignment_method
5371 LOC: Config.Wccp2.assignment_method
5375 WCCP2 allows the setting of methods to assign the WCCP hash
5376 Valid values are as follows:
5378 hash - Hash assignment
5379 mask - Mask assignment
5381 As a general rule, cisco routers support the hash assignment method
5382 and cisco switches support the mask assignment method.
5387 LOC: Config.Wccp2.info
5388 DEFAULT_IF_NONE: standard 0
5391 WCCP2 allows for multiple traffic services. There are two
5392 types: "standard" and "dynamic". The standard type defines
5393 one service id - http (id 0). The dynamic service ids can be from
5394 51 to 255 inclusive. In order to use a dynamic service id
5395 one must define the type of traffic to be redirected; this is done
5396 using the wccp2_service_info option.
5398 The "standard" type does not require a wccp2_service_info option,
5399 just specifying the service id will suffice.
5401 MD5 service authentication can be enabled by adding
5402 "password=<password>" to the end of this service declaration.
5406 wccp2_service standard 0 # for the 'web-cache' standard service
5407 wccp2_service dynamic 80 # a dynamic service type which will be
5408 # fleshed out with subsequent options.
5409 wccp2_service standard 0 password=foo
5412 NAME: wccp2_service_info
5413 TYPE: wccp2_service_info
5414 LOC: Config.Wccp2.info
5418 Dynamic WCCPv2 services require further information to define the
5419 traffic you wish to have diverted.
5423 wccp2_service_info <id> protocol=<protocol> flags=<flag>,<flag>..
5424 priority=<priority> ports=<port>,<port>..
5426 The relevant WCCPv2 flags:
5427 + src_ip_hash, dst_ip_hash
5428 + source_port_hash, dst_port_hash
5429 + src_ip_alt_hash, dst_ip_alt_hash
5430 + src_port_alt_hash, dst_port_alt_hash
5433 The port list can be one to eight entries.
5437 wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source
5438 priority=240 ports=80
5440 Note: the service id must have been defined by a previous
5441 'wccp2_service dynamic <id>' entry.
5446 LOC: Config.Wccp2.weight
5450 Each cache server gets assigned a set of the destination
5451 hash proportional to their weight.
5456 LOC: Config.Wccp.address
5463 LOC: Config.Wccp2.address
5467 Use this option if you require WCCP to use a specific
5470 The default behavior is to not bind to any specific address.
5474 PERSISTENT CONNECTION HANDLING
5475 -----------------------------------------------------------------------------
5477 Also see "pconn_timeout" in the TIMEOUTS section
5480 NAME: client_persistent_connections
5482 LOC: Config.onoff.client_pconns
5486 NAME: server_persistent_connections
5488 LOC: Config.onoff.server_pconns
5491 Persistent connection support for clients and servers. By
5492 default, Squid uses persistent connections (when allowed)
5493 with its clients and servers. You can use these options to
5494 disable persistent connections with clients and/or servers.
5497 NAME: persistent_connection_after_error
5499 LOC: Config.onoff.error_pconns
5502 With this directive the use of persistent connections after
5503 HTTP errors can be disabled. Useful if you have clients
5504 who fail to handle errors on persistent connections proper.
5507 NAME: detect_broken_pconn
5509 LOC: Config.onoff.detect_broken_server_pconns
5512 Some servers have been found to incorrectly signal the use
5513 of HTTP/1.0 persistent connections even on replies not
5514 compatible, causing significant delays. This server problem
5515 has mostly been seen on redirects.
5517 By enabling this directive Squid attempts to detect such
5518 broken replies and automatically assume the reply is finished
5519 after 10 seconds timeout.
5523 CACHE DIGEST OPTIONS
5524 -----------------------------------------------------------------------------
5527 NAME: digest_generation
5528 IFDEF: USE_CACHE_DIGESTS
5530 LOC: Config.onoff.digest_generation
5533 This controls whether the server will generate a Cache Digest
5534 of its contents. By default, Cache Digest generation is
5535 enabled if Squid is compiled with --enable-cache-digests defined.
5538 NAME: digest_bits_per_entry
5539 IFDEF: USE_CACHE_DIGESTS
5541 LOC: Config.digest.bits_per_entry
5544 This is the number of bits of the server's Cache Digest which
5545 will be associated with the Digest entry for a given HTTP
5546 Method and URL (public key) combination. The default is 5.
5549 NAME: digest_rebuild_period
5550 IFDEF: USE_CACHE_DIGESTS
5553 LOC: Config.digest.rebuild_period
5556 This is the wait time between Cache Digest rebuilds.
5559 NAME: digest_rewrite_period
5561 IFDEF: USE_CACHE_DIGESTS
5563 LOC: Config.digest.rewrite_period
5566 This is the wait time between Cache Digest writes to
5570 NAME: digest_swapout_chunk_size
5573 IFDEF: USE_CACHE_DIGESTS
5574 LOC: Config.digest.swapout_chunk_size
5577 This is the number of bytes of the Cache Digest to write to
5578 disk at a time. It defaults to 4096 bytes (4KB), the Squid
5582 NAME: digest_rebuild_chunk_percentage
5583 COMMENT: (percent, 0-100)
5584 IFDEF: USE_CACHE_DIGESTS
5586 LOC: Config.digest.rebuild_chunk_percentage
5589 This is the percentage of the Cache Digest to be scanned at a
5590 time. By default it is set to 10% of the Cache Digest.
5595 -----------------------------------------------------------------------------
5600 LOC: Config.Port.snmp
5604 The port number where Squid listens for SNMP requests. To enable
5605 SNMP support set this to a suitable port number. Port number
5606 3401 is often used for the Squid SNMP agent. By default it's
5607 set to "0" (disabled)
5615 LOC: Config.accessList.snmp
5616 DEFAULT_IF_NONE: deny all
5619 Allowing or denying access to the SNMP port.
5621 All access to the agent is denied by default.
5624 snmp_access allow|deny [!]aclname ...
5626 This clause only supports fast acl types.
5627 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5629 snmp_access allow snmppublic localhost
5630 snmp_access deny all
5633 NAME: snmp_incoming_address
5635 LOC: Config.Addrs.snmp_incoming
5640 NAME: snmp_outgoing_address
5642 LOC: Config.Addrs.snmp_outgoing
5646 Just like 'udp_incoming_address', but for the SNMP port.
5648 snmp_incoming_address is used for the SNMP socket receiving
5649 messages from SNMP agents.
5650 snmp_outgoing_address is used for SNMP packets returned to SNMP
5653 The default snmp_incoming_address is to listen on all
5654 available network interfaces.
5656 If snmp_outgoing_address is not set it will use the same socket
5657 as snmp_incoming_address. Only change this if you want to have
5658 SNMP replies sent using another address than where this Squid
5659 listens for SNMP queries.
5661 NOTE, snmp_incoming_address and snmp_outgoing_address can not have
5662 the same value since they both use port 3401.
5667 -----------------------------------------------------------------------------
5670 NAME: icp_port udp_port
5673 LOC: Config.Port.icp
5675 The port number where Squid sends and receives ICP queries to
5676 and from neighbor caches. The standard UDP port for ICP is 3130.
5677 Default is disabled (0).
5680 icp_port @DEFAULT_ICP_PORT@
5687 LOC: Config.Port.htcp
5689 The port number where Squid sends and receives HTCP queries to
5690 and from neighbor caches. To turn it on you want to set it to
5691 4827. By default it is set to "0" (disabled).
5697 NAME: log_icp_queries
5701 LOC: Config.onoff.log_udp
5703 If set, ICP queries are logged to access.log. You may wish
5704 do disable this if your ICP load is VERY high to speed things
5705 up or to simplify log analysis.
5708 NAME: udp_incoming_address
5710 LOC:Config.Addrs.udp_incoming
5713 udp_incoming_address is used for UDP packets received from other
5716 The default behavior is to not bind to any specific address.
5718 Only change this if you want to have all UDP queries received on
5719 a specific interface/address.
5721 NOTE: udp_incoming_address is used by the ICP, HTCP, and DNS
5722 modules. Altering it will affect all of them in the same manner.
5724 see also; udp_outgoing_address
5726 NOTE, udp_incoming_address and udp_outgoing_address can not
5727 have the same value since they both use the same port.
5730 NAME: udp_outgoing_address
5732 LOC: Config.Addrs.udp_outgoing
5735 udp_outgoing_address is used for UDP packets sent out to other
5738 The default behavior is to not bind to any specific address.
5740 Instead it will use the same socket as udp_incoming_address.
5741 Only change this if you want to have UDP queries sent using another
5742 address than where this Squid listens for UDP queries from other
5745 NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS
5746 modules. Altering it will affect all of them in the same manner.
5748 see also; udp_incoming_address
5750 NOTE, udp_incoming_address and udp_outgoing_address can not
5751 have the same value since they both use the same port.
5758 LOC: Config.onoff.icp_hit_stale
5760 If you want to return ICP_HIT for stale cache objects, set this
5761 option to 'on'. If you have sibling relationships with caches
5762 in other administrative domains, this should be 'off'. If you only
5763 have sibling relationships with caches under your control,
5764 it is probably okay to set this to 'on'.
5765 If set to 'on', your siblings should use the option "allow-miss"
5766 on their cache_peer lines for connecting to you.
5769 NAME: minimum_direct_hops
5772 LOC: Config.minDirectHops
5774 If using the ICMP pinging stuff, do direct fetches for sites
5775 which are no more than this many hops away.
5778 NAME: minimum_direct_rtt
5781 LOC: Config.minDirectRtt
5783 If using the ICMP pinging stuff, do direct fetches for sites
5784 which are no more than this many rtt milliseconds away.
5790 LOC: Config.Netdb.low
5796 LOC: Config.Netdb.high
5798 The low and high water marks for the ICMP measurement
5799 database. These are counts, not percents. The defaults are
5800 900 and 1000. When the high water mark is reached, database
5801 entries will be deleted until the low mark is reached.
5804 NAME: netdb_ping_period
5806 LOC: Config.Netdb.period
5809 The minimum period for measuring a site. There will be at
5810 least this much delay between successive pings to the same
5811 network. The default is five minutes.
5818 LOC: Config.onoff.query_icmp
5820 If you want to ask your peers to include ICMP data in their ICP
5821 replies, enable this option.
5823 If your peer has configured Squid (during compilation) with
5824 '--enable-icmp' that peer will send ICMP pings to origin server
5825 sites of the URLs it receives. If you enable this option the
5826 ICP replies from that peer will include the ICMP data (if available).
5827 Then, when choosing a parent cache, Squid will choose the parent with
5828 the minimal RTT to the origin server. When this happens, the
5829 hierarchy field of the access.log will be
5830 "CLOSEST_PARENT_MISS". This option is off by default.
5833 NAME: test_reachability
5837 LOC: Config.onoff.test_reachability
5839 When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
5840 instead of ICP_MISS if the target host is NOT in the ICMP
5841 database, or has a zero RTT.
5844 NAME: icp_query_timeout
5848 LOC: Config.Timeout.icp_query
5850 Normally Squid will automatically determine an optimal ICP
5851 query timeout value based on the round-trip-time of recent ICP
5852 queries. If you want to override the value determined by
5853 Squid, set this 'icp_query_timeout' to a non-zero value. This
5854 value is specified in MILLISECONDS, so, to use a 2-second
5855 timeout (the old default), you would write:
5857 icp_query_timeout 2000
5860 NAME: maximum_icp_query_timeout
5864 LOC: Config.Timeout.icp_query_max
5866 Normally the ICP query timeout is determined dynamically. But
5867 sometimes it can lead to very large values (say 5 seconds).
5868 Use this option to put an upper limit on the dynamic timeout
5869 value. Do NOT use this option to always use a fixed (instead
5870 of a dynamic) timeout value. To set a fixed timeout see the
5871 'icp_query_timeout' directive.
5874 NAME: minimum_icp_query_timeout
5878 LOC: Config.Timeout.icp_query_min
5880 Normally the ICP query timeout is determined dynamically. But
5881 sometimes it can lead to very small timeouts, even lower than
5882 the normal latency variance on your link due to traffic.
5883 Use this option to put an lower limit on the dynamic timeout
5884 value. Do NOT use this option to always use a fixed (instead
5885 of a dynamic) timeout value. To set a fixed timeout see the
5886 'icp_query_timeout' directive.
5889 NAME: background_ping_rate
5893 LOC: Config.backgroundPingRate
5895 Controls how often the ICP pings are sent to siblings that
5896 have background-ping set.
5900 MULTICAST ICP OPTIONS
5901 -----------------------------------------------------------------------------
5906 LOC: Config.mcast_group_list
5909 This tag specifies a list of multicast groups which your server
5910 should join to receive multicasted ICP queries.
5912 NOTE! Be very careful what you put here! Be sure you
5913 understand the difference between an ICP _query_ and an ICP
5914 _reply_. This option is to be set only if you want to RECEIVE
5915 multicast queries. Do NOT set this option to SEND multicast
5916 ICP (use cache_peer for that). ICP replies are always sent via
5917 unicast, so this option does not affect whether or not you will
5918 receive replies from multicast group members.
5920 You must be very careful to NOT use a multicast address which
5921 is already in use by another group of caches.
5923 If you are unsure about multicast, please read the Multicast
5924 chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
5926 Usage: mcast_groups 239.128.16.128 224.0.1.20
5928 By default, Squid doesn't listen on any multicast groups.
5931 NAME: mcast_miss_addr
5932 IFDEF: MULTICAST_MISS_STREAM
5934 LOC: Config.mcast_miss.addr
5937 If you enable this option, every "cache miss" URL will
5938 be sent out on the specified multicast address.
5940 Do not enable this option unless you are are absolutely
5941 certain you understand what you are doing.
5944 NAME: mcast_miss_ttl
5945 IFDEF: MULTICAST_MISS_STREAM
5947 LOC: Config.mcast_miss.ttl
5950 This is the time-to-live value for packets multicasted
5951 when multicasting off cache miss URLs is enabled. By
5952 default this is set to 'site scope', i.e. 16.
5955 NAME: mcast_miss_port
5956 IFDEF: MULTICAST_MISS_STREAM
5958 LOC: Config.mcast_miss.port
5961 This is the port number to be used in conjunction with
5965 NAME: mcast_miss_encode_key
5966 IFDEF: MULTICAST_MISS_STREAM
5968 LOC: Config.mcast_miss.encode_key
5969 DEFAULT: XXXXXXXXXXXXXXXX
5971 The URLs that are sent in the multicast miss stream are
5972 encrypted. This is the encryption key.
5975 NAME: mcast_icp_query_timeout
5979 LOC: Config.Timeout.mcast_icp_query
5981 For multicast peers, Squid regularly sends out ICP "probes" to
5982 count how many other peers are listening on the given multicast
5983 address. This value specifies how long Squid should wait to
5984 count all the replies. The default is 2000 msec, or 2
5989 INTERNAL ICON OPTIONS
5990 -----------------------------------------------------------------------------
5993 NAME: icon_directory
5995 LOC: Config.icons.directory
5996 DEFAULT: @DEFAULT_ICON_DIR@
5998 Where the icons are stored. These are normally kept in
6002 NAME: global_internal_static
6004 LOC: Config.onoff.global_internal_static
6007 This directive controls is Squid should intercept all requests for
6008 /squid-internal-static/ no matter which host the URL is requesting
6009 (default on setting), or if nothing special should be done for
6010 such URLs (off setting). The purpose of this directive is to make
6011 icons etc work better in complex cache hierarchies where it may
6012 not always be possible for all corners in the cache mesh to reach
6013 the server generating a directory listing.
6016 NAME: short_icon_urls
6018 LOC: Config.icons.use_short_names
6021 If this is enabled Squid will use short URLs for icons.
6022 If disabled it will revert to the old behavior of including
6023 it's own name and port in the URL.
6025 If you run a complex cache hierarchy with a mix of Squid and
6026 other proxies you may need to disable this directive.
6031 -----------------------------------------------------------------------------
6034 NAME: error_directory
6036 LOC: Config.errorDirectory
6039 If you wish to create your own versions of the default
6040 error files to customize them to suit your company copy
6041 the error/template files to another directory and point
6044 WARNING: This option will disable multi-language support
6045 on error pages if used.
6047 The squid developers are interested in making squid available in
6048 a wide variety of languages. If you are making translations for a
6049 language that Squid does not currently provide please consider
6050 contributing your translation back to the project.
6051 http://wiki.squid-cache.org/Translations
6053 The squid developers working on translations are happy to supply drop-in
6054 translated error files in exchange for any new language contributions.
6057 NAME: error_default_language
6058 IFDEF: USE_ERR_LOCALES
6060 LOC: Config.errorDefaultLanguage
6063 Set the default language which squid will send error pages in
6064 if no existing translation matches the clients language
6067 If unset (default) generic English will be used.
6069 The squid developers are interested in making squid available in
6070 a wide variety of languages. If you are interested in making
6071 translations for any language see the squid wiki for details.
6072 http://wiki.squid-cache.org/Translations
6075 NAME: error_log_languages
6076 IFDEF: USE_ERR_LOCALES
6078 LOC: Config.errorLogMissingLanguages
6081 Log to cache.log what languages users are attempting to
6082 auto-negotiate for translations.
6084 Successful negotiations are not logged. Only failures
6085 have meaning to indicate that Squid may need an upgrade
6086 of its error page translations.
6089 NAME: err_page_stylesheet
6091 LOC: Config.errorStylesheet
6092 DEFAULT: @DEFAULT_CONFIG_DIR@/errorpage.css
6094 CSS Stylesheet to pattern the display of Squid default error pages.
6096 For information on CSS see http://www.w3.org/Style/CSS/
6101 LOC: Config.errHtmlText
6104 HTML text to include in error messages. Make this a "mailto"
6105 URL to your admin address, or maybe just a link to your
6106 organizations Web page.
6108 To include this in your error messages, you must rewrite
6109 the error template files (found in the "errors" directory).
6110 Wherever you want the 'err_html_text' line to appear,
6111 insert a %L tag in the error template file.
6114 NAME: email_err_data
6117 LOC: Config.onoff.emailErrData
6120 If enabled, information about the occurred error will be
6121 included in the mailto links of the ERR pages (if %W is set)
6122 so that the email body contains the data.
6123 Syntax is <A HREF="mailto:%w%W">%w</A>
6128 LOC: Config.denyInfoList
6131 Usage: deny_info err_page_name acl
6132 or deny_info http://... acl
6133 or deny_info TCP_RESET acl
6135 This can be used to return a ERR_ page for requests which
6136 do not pass the 'http_access' rules. Squid remembers the last
6137 acl it evaluated in http_access, and if a 'deny_info' line exists
6138 for that ACL Squid returns a corresponding error page.
6140 The acl is typically the last acl on the http_access deny line which
6141 denied access. The exceptions to this rule are:
6142 - When Squid needs to request authentication credentials. It's then
6143 the first authentication related acl encountered
6144 - When none of the http_access lines matches. It's then the last
6145 acl processed on the last http_access line.
6146 - When the decision to deny access was made by an adaptation service,
6147 the acl name is the corresponding eCAP or ICAP service_name.
6149 NP: If providing your own custom error pages with error_directory
6150 you may also specify them by your custom file name:
6151 Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
6153 By defaut Squid will send "403 Forbidden". A different 4xx or 5xx
6154 may be specified by prefixing the file name with the code and a colon.
6155 e.g. 404:ERR_CUSTOM_ACCESS_DENIED
6157 Alternatively you can tell Squid to reset the TCP connection
6158 by specifying TCP_RESET.
6160 Or you can specify an error URL or URL pattern. The browsers will
6161 get redirected to the specified URL after formatting tags have
6162 been replaced. Redirect will be done with 302 or 307 according to
6163 HTTP/1.1 specs. A different 3xx code may be specified by prefixing
6164 the URL. e.g. 303:http://example.com/
6167 %a - username (if available. Password NOT included)
6170 %E - Error description
6172 %H - Request domain name
6173 %i - Client IP Address
6175 %o - Message result from external ACL helper
6176 %p - Request Port number
6177 %P - Request Protocol name
6178 %R - Request URL path
6179 %T - Timestamp in RFC 1123 format
6180 %U - Full canonical URL from client
6181 (HTTPS URLs terminate with *)
6182 %u - Full canonical URL from client
6183 %w - Admin email from squid.conf
6185 %% - Literal percent (%) code
6190 OPTIONS INFLUENCING REQUEST FORWARDING
6191 -----------------------------------------------------------------------------
6194 NAME: nonhierarchical_direct
6196 LOC: Config.onoff.nonhierarchical_direct
6199 By default, Squid will send any non-hierarchical requests
6200 (matching hierarchy_stoplist or not cacheable request type) direct
6203 If you set this to off, Squid will prefer to send these
6204 requests to parents.
6206 Note that in most configurations, by turning this off you will only
6207 add latency to these request without any improvement in global hit
6210 If you are inside an firewall see never_direct instead of
6216 LOC: Config.onoff.prefer_direct
6219 Normally Squid tries to use parents for most requests. If you for some
6220 reason like it to first try going direct and only use a parent if
6221 going direct fails set this to on.
6223 By combining nonhierarchical_direct off and prefer_direct on you
6224 can set up Squid to use a parent as a backup path if going direct
6227 Note: If you want Squid to use parents for all requests see
6228 the never_direct directive. prefer_direct only modifies how Squid
6229 acts on cacheable requests.
6234 LOC: Config.accessList.AlwaysDirect
6237 Usage: always_direct allow|deny [!]aclname ...
6239 Here you can use ACL elements to specify requests which should
6240 ALWAYS be forwarded by Squid to the origin servers without using
6241 any peers. For example, to always directly forward requests for
6242 local servers ignoring any parents or siblings you may have use
6245 acl local-servers dstdomain my.domain.net
6246 always_direct allow local-servers
6248 To always forward FTP requests directly, use
6251 always_direct allow FTP
6253 NOTE: There is a similar, but opposite option named
6254 'never_direct'. You need to be aware that "always_direct deny
6255 foo" is NOT the same thing as "never_direct allow foo". You
6256 may need to use a deny rule to exclude a more-specific case of
6257 some other rule. Example:
6259 acl local-external dstdomain external.foo.net
6260 acl local-servers dstdomain .foo.net
6261 always_direct deny local-external
6262 always_direct allow local-servers
6264 NOTE: If your goal is to make the client forward the request
6265 directly to the origin server bypassing Squid then this needs
6266 to be done in the client configuration. Squid configuration
6267 can only tell Squid how Squid should fetch the object.
6269 NOTE: This directive is not related to caching. The replies
6270 is cached as usual even if you use always_direct. To not cache
6271 the replies see the 'cache' directive.
6273 This clause supports both fast and slow acl types.
6274 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6279 LOC: Config.accessList.NeverDirect
6282 Usage: never_direct allow|deny [!]aclname ...
6284 never_direct is the opposite of always_direct. Please read
6285 the description for always_direct if you have not already.
6287 With 'never_direct' you can use ACL elements to specify
6288 requests which should NEVER be forwarded directly to origin
6289 servers. For example, to force the use of a proxy for all
6290 requests, except those in your local domain use something like:
6292 acl local-servers dstdomain .foo.net
6293 never_direct deny local-servers
6294 never_direct allow all
6296 or if Squid is inside a firewall and there are local intranet
6297 servers inside the firewall use something like:
6299 acl local-intranet dstdomain .foo.net
6300 acl local-external dstdomain external.foo.net
6301 always_direct deny local-external
6302 always_direct allow local-intranet
6303 never_direct allow all
6305 This clause supports both fast and slow acl types.
6306 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6310 ADVANCED NETWORKING OPTIONS
6311 -----------------------------------------------------------------------------
6314 NAME: incoming_icp_average
6317 LOC: Config.comm_incoming.icp_average
6320 NAME: incoming_http_average
6323 LOC: Config.comm_incoming.http_average
6326 NAME: incoming_dns_average
6329 LOC: Config.comm_incoming.dns_average
6332 NAME: min_icp_poll_cnt
6335 LOC: Config.comm_incoming.icp_min_poll
6338 NAME: min_dns_poll_cnt
6341 LOC: Config.comm_incoming.dns_min_poll
6344 NAME: min_http_poll_cnt
6347 LOC: Config.comm_incoming.http_min_poll
6349 Heavy voodoo here. I can't even believe you are reading this.
6350 Are you crazy? Don't even think about adjusting these unless
6351 you understand the algorithms in comm_select.c first!
6357 LOC: Config.accept_filter
6361 The name of an accept(2) filter to install on Squid's
6362 listen socket(s). This feature is perhaps specific to
6363 FreeBSD and requires support in the kernel.
6365 The 'httpready' filter delays delivering new connections
6366 to Squid until a full HTTP request has been received.
6367 See the accf_http(9) man page for details.
6369 The 'dataready' filter delays delivering new connections
6370 to Squid until there is some data to process.
6371 See the accf_dataready(9) man page for details.
6375 The 'data' filter delays delivering of new connections
6376 to Squid until there is some data to process by TCP_ACCEPT_DEFER.
6377 You may optionally specify a number of seconds to wait by
6378 'data=N' where N is the number of seconds. Defaults to 30
6379 if not specified. See the tcp(7) man page for details.
6382 accept_filter httpready
6387 NAME: client_ip_max_connections
6389 LOC: Config.client_ip_max_connections
6392 Set an absolute limit on the number of connections a single
6393 client IP can use. Any more than this and Squid will begin to drop
6394 new connections from the client until it closes some links.
6396 Note that this is a global limit. It affects all HTTP, HTCP, Gopher and FTP
6397 connections from the client. For finer control use the ACL access controls.
6399 Requires client_db to be enabled (the default).
6401 WARNING: This may noticably slow down traffic received via external proxies
6402 or NAT devices and cause them to rebound error messages back to their clients.
6405 NAME: tcp_recv_bufsize
6409 LOC: Config.tcpRcvBufsz
6411 Size of receive buffer to set for TCP sockets. Probably just
6412 as easy to change your kernel's default. Set to zero to use
6413 the default buffer size.
6418 -----------------------------------------------------------------------------
6425 LOC: Adaptation::Icap::TheConfig.onoff
6428 If you want to enable the ICAP module support, set this to on.
6431 NAME: icap_connect_timeout
6434 LOC: Adaptation::Icap::TheConfig.connect_timeout_raw
6437 This parameter specifies how long to wait for the TCP connect to
6438 the requested ICAP server to complete before giving up and either
6439 terminating the HTTP transaction or bypassing the failure.
6441 The default for optional services is peer_connect_timeout.
6442 The default for essential services is connect_timeout.
6443 If this option is explicitly set, its value applies to all services.
6446 NAME: icap_io_timeout
6450 LOC: Adaptation::Icap::TheConfig.io_timeout_raw
6453 This parameter specifies how long to wait for an I/O activity on
6454 an established, active ICAP connection before giving up and
6455 either terminating the HTTP transaction or bypassing the
6458 The default is read_timeout.
6461 NAME: icap_service_failure_limit
6462 COMMENT: limit [in memory-depth time-units]
6463 TYPE: icap_service_failure_limit
6465 LOC: Adaptation::Icap::TheConfig
6468 The limit specifies the number of failures that Squid tolerates
6469 when establishing a new TCP connection with an ICAP service. If
6470 the number of failures exceeds the limit, the ICAP service is
6471 not used for new ICAP requests until it is time to refresh its
6474 A negative value disables the limit. Without the limit, an ICAP
6475 service will not be considered down due to connectivity failures
6476 between ICAP OPTIONS requests.
6478 Squid forgets ICAP service failures older than the specified
6479 value of memory-depth. The memory fading algorithm
6480 is approximate because Squid does not remember individual
6481 errors but groups them instead, splitting the option
6482 value into ten time slots of equal length.
6484 When memory-depth is 0 and by default this option has no
6485 effect on service failure expiration.
6487 Squid always forgets failures when updating service settings
6488 using an ICAP OPTIONS transaction, regardless of this option
6492 # suspend service usage after 10 failures in 5 seconds:
6493 icap_service_failure_limit 10 in 5 seconds
6496 NAME: icap_service_revival_delay
6499 LOC: Adaptation::Icap::TheConfig.service_revival_delay
6502 The delay specifies the number of seconds to wait after an ICAP
6503 OPTIONS request failure before requesting the options again. The
6504 failed ICAP service is considered "down" until fresh OPTIONS are
6507 The actual delay cannot be smaller than the hardcoded minimum
6508 delay of 30 seconds.
6511 NAME: icap_preview_enable
6515 LOC: Adaptation::Icap::TheConfig.preview_enable
6518 The ICAP Preview feature allows the ICAP server to handle the
6519 HTTP message by looking only at the beginning of the message body
6520 or even without receiving the body at all. In some environments,
6521 previews greatly speedup ICAP processing.
6523 During an ICAP OPTIONS transaction, the server may tell Squid what
6524 HTTP messages should be previewed and how big the preview should be.
6525 Squid will not use Preview if the server did not request one.
6527 To disable ICAP Preview for all ICAP services, regardless of
6528 individual ICAP server OPTIONS responses, set this option to "off".
6530 icap_preview_enable off
6533 NAME: icap_preview_size
6536 LOC: Adaptation::Icap::TheConfig.preview_size
6539 The default size of preview data to be sent to the ICAP server.
6540 -1 means no preview. This value might be overwritten on a per server
6541 basis by OPTIONS requests.
6544 NAME: icap_206_enable
6548 LOC: Adaptation::Icap::TheConfig.allow206_enable
6551 206 (Partial Content) responses is an ICAP extension that allows the
6552 ICAP agents to optionally combine adapted and original HTTP message
6553 content. The decision to combine is postponed until the end of the
6554 ICAP response. Squid supports Partial Content extension by default.
6556 Activation of the Partial Content extension is negotiated with each
6557 ICAP service during OPTIONS exchange. Most ICAP servers should handle
6558 negotation correctly even if they do not support the extension, but
6559 some might fail. To disable Partial Content support for all ICAP
6560 services and to avoid any negotiation, set this option to "off".
6566 NAME: icap_default_options_ttl
6569 LOC: Adaptation::Icap::TheConfig.default_options_ttl
6572 The default TTL value for ICAP OPTIONS responses that don't have
6573 an Options-TTL header.
6576 NAME: icap_persistent_connections
6580 LOC: Adaptation::Icap::TheConfig.reuse_connections
6583 Whether or not Squid should use persistent connections to
6587 NAME: adaptation_send_client_ip icap_send_client_ip
6589 IFDEF: USE_ADAPTATION
6591 LOC: Adaptation::Config::send_client_ip
6594 If enabled, Squid shares HTTP client IP information with adaptation
6595 services. For ICAP, Squid adds the X-Client-IP header to ICAP requests.
6596 For eCAP, Squid sets the libecap::metaClientIp transaction option.
6598 See also: adaptation_uses_indirect_client
6601 NAME: adaptation_send_username icap_send_client_username
6603 IFDEF: USE_ADAPTATION
6605 LOC: Adaptation::Config::send_username
6608 This sends authenticated HTTP client username (if available) to
6609 the adaptation service.
6611 For ICAP, the username value is encoded based on the
6612 icap_client_username_encode option and is sent using the header
6613 specified by the icap_client_username_header option.
6616 NAME: icap_client_username_header
6619 LOC: Adaptation::Icap::TheConfig.client_username_header
6620 DEFAULT: X-Client-Username
6622 ICAP request header name to use for adaptation_send_username.
6625 NAME: icap_client_username_encode
6629 LOC: Adaptation::Icap::TheConfig.client_username_encode
6632 Whether to base64 encode the authenticated client username.
6636 TYPE: icap_service_type
6638 LOC: Adaptation::Icap::TheConfig
6641 Defines a single ICAP service using the following format:
6643 icap_service id vectoring_point uri [option ...]
6646 an opaque identifier or name which is used to direct traffic to
6647 this specific service. Must be unique among all adaptation
6648 services in squid.conf.
6650 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
6651 This specifies at which point of transaction processing the
6652 ICAP service should be activated. *_postcache vectoring points
6653 are not yet supported.
6655 uri: icap://servername:port/servicepath
6656 ICAP server and service location.
6658 ICAP does not allow a single service to handle both REQMOD and RESPMOD
6659 transactions. Squid does not enforce that requirement. You can specify
6660 services with the same service_url and different vectoring_points. You
6661 can even specify multiple identical services as long as their
6662 service_names differ.
6665 Service options are separated by white space. ICAP services support
6666 the following name=value options:
6669 If set to 'on' or '1', the ICAP service is treated as
6670 optional. If the service cannot be reached or malfunctions,
6671 Squid will try to ignore any errors and process the message as
6672 if the service was not enabled. No all ICAP errors can be
6673 bypassed. If set to 0, the ICAP service is treated as
6674 essential and all ICAP errors will result in an error page
6675 returned to the HTTP client.
6677 Bypass is off by default: services are treated as essential.
6680 If set to 'on' or '1', the ICAP service is allowed to
6681 dynamically change the current message adaptation plan by
6682 returning a chain of services to be used next. The services
6683 are specified using the X-Next-Services ICAP response header
6684 value, formatted as a comma-separated list of service names.
6685 Each named service should be configured in squid.conf. Other
6686 services are ignored. An empty X-Next-Services value results
6687 in an empty plan which ends the current adaptation.
6689 Dynamic adaptation plan may cross or cover multiple supported
6690 vectoring points in their natural processing order.
6692 Routing is not allowed by default: the ICAP X-Next-Services
6693 response header is ignored.
6696 Only has effect on split-stack systems. The default on those systems
6697 is to use IPv4-only connections. When set to 'on' this option will
6698 make Squid use IPv6-only connections to contact this ICAP service.
6700 on-overload=block|bypass|wait|force
6701 If the service Max-Connections limit has been reached, do
6702 one of the following for each new ICAP transaction:
6703 * block: send an HTTP error response to the client
6704 * bypass: ignore the "over-connected" ICAP service
6705 * wait: wait (in a FIFO queue) for an ICAP connection slot
6706 * force: proceed, ignoring the Max-Connections limit
6708 In SMP mode with N workers, each worker assumes the service
6709 connection limit is Max-Connections/N, even though not all
6710 workers may use a given service.
6712 The default value is "bypass" if service is bypassable,
6713 otherwise it is set to "wait".
6717 Use the given number as the Max-Connections limit, regardless
6718 of the Max-Connections value given by the service, if any.
6720 Older icap_service format without optional named parameters is
6721 deprecated but supported for backward compatibility.
6724 icap_service svcBlocker reqmod_precache icap://icap1.mydomain.net:1344/reqmod bypass=0
6725 icap_service svcLogger reqmod_precache icap://icap2.mydomain.net:1344/respmod routing=on
6729 TYPE: icap_class_type
6734 This deprecated option was documented to define an ICAP service
6735 chain, even though it actually defined a set of similar, redundant
6736 services, and the chains were not supported.
6738 To define a set of redundant services, please use the
6739 adaptation_service_set directive. For service chains, use
6740 adaptation_service_chain.
6744 TYPE: icap_access_type
6749 This option is deprecated. Please use adaptation_access, which
6750 has the same ICAP functionality, but comes with better
6751 documentation, and eCAP support.
6756 -----------------------------------------------------------------------------
6763 LOC: Adaptation::Ecap::TheConfig.onoff
6766 Controls whether eCAP support is enabled.
6770 TYPE: ecap_service_type
6772 LOC: Adaptation::Ecap::TheConfig
6775 Defines a single eCAP service
6777 ecap_service id vectoring_point uri [option ...]
6780 an opaque identifier or name which is used to direct traffic to
6781 this specific service. Must be unique among all adaptation
6782 services in squid.conf.
6784 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
6785 This specifies at which point of transaction processing the
6786 eCAP service should be activated. *_postcache vectoring points
6787 are not yet supported.
6789 uri: ecap://vendor/service_name?custom&cgi=style¶meters=optional
6790 Squid uses the eCAP service URI to match this configuration
6791 line with one of the dynamically loaded services. Each loaded
6792 eCAP service must have a unique URI. Obtain the right URI from
6793 the service provider.
6796 Service options are separated by white space. eCAP services support
6797 the following name=value options:
6800 If set to 'on' or '1', the eCAP service is treated as optional.
6801 If the service cannot be reached or malfunctions, Squid will try
6802 to ignore any errors and process the message as if the service
6803 was not enabled. No all eCAP errors can be bypassed.
6804 If set to 'off' or '0', the eCAP service is treated as essential
6805 and all eCAP errors will result in an error page returned to the
6808 Bypass is off by default: services are treated as essential.
6811 If set to 'on' or '1', the eCAP service is allowed to
6812 dynamically change the current message adaptation plan by
6813 returning a chain of services to be used next.
6815 Dynamic adaptation plan may cross or cover multiple supported
6816 vectoring points in their natural processing order.
6818 Routing is not allowed by default.
6820 Older ecap_service format without optional named parameters is
6821 deprecated but supported for backward compatibility.
6825 ecap_service s1 reqmod_precache ecap://filters.R.us/leakDetector?on_error=block bypass=off
6826 ecap_service s2 respmod_precache ecap://filters.R.us/virusFilter config=/etc/vf.cfg bypass=on
6829 NAME: loadable_modules
6831 IFDEF: USE_LOADABLE_MODULES
6832 LOC: Config.loadable_module_names
6835 Instructs Squid to load the specified dynamic module(s) or activate
6836 preloaded module(s).
6838 loadable_modules @DEFAULT_PREFIX@/lib/MinimalAdapter.so
6842 MESSAGE ADAPTATION OPTIONS
6843 -----------------------------------------------------------------------------
6846 NAME: adaptation_service_set
6847 TYPE: adaptation_service_set_type
6848 IFDEF: USE_ADAPTATION
6853 Configures an ordered set of similar, redundant services. This is
6854 useful when hot standby or backup adaptation servers are available.
6856 adaptation_service_set set_name service_name1 service_name2 ...
6858 The named services are used in the set declaration order. The first
6859 applicable adaptation service from the set is used first. The next
6860 applicable service is tried if and only if the transaction with the
6861 previous service fails and the message waiting to be adapted is still
6864 When adaptation starts, broken services are ignored as if they were
6865 not a part of the set. A broken service is a down optional service.
6867 The services in a set must be attached to the same vectoring point
6868 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
6870 If all services in a set are optional then adaptation failures are
6871 bypassable. If all services in the set are essential, then a
6872 transaction failure with one service may still be retried using
6873 another service from the set, but when all services fail, the master
6874 transaction fails as well.
6876 A set may contain a mix of optional and essential services, but that
6877 is likely to lead to surprising results because broken services become
6878 ignored (see above), making previously bypassable failures fatal.
6879 Technically, it is the bypassability of the last failed service that
6882 See also: adaptation_access adaptation_service_chain
6885 adaptation_service_set svcBlocker urlFilterPrimary urlFilterBackup
6886 adaptation service_set svcLogger loggerLocal loggerRemote
6889 NAME: adaptation_service_chain
6890 TYPE: adaptation_service_chain_type
6891 IFDEF: USE_ADAPTATION
6896 Configures a list of complementary services that will be applied
6897 one-by-one, forming an adaptation chain or pipeline. This is useful
6898 when Squid must perform different adaptations on the same message.
6900 adaptation_service_chain chain_name service_name1 svc_name2 ...
6902 The named services are used in the chain declaration order. The first
6903 applicable adaptation service from the chain is used first. The next
6904 applicable service is applied to the successful adaptation results of
6905 the previous service in the chain.
6907 When adaptation starts, broken services are ignored as if they were
6908 not a part of the chain. A broken service is a down optional service.
6910 Request satisfaction terminates the adaptation chain because Squid
6911 does not currently allow declaration of RESPMOD services at the
6912 "reqmod_precache" vectoring point (see icap_service or ecap_service).
6914 The services in a chain must be attached to the same vectoring point
6915 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
6917 A chain may contain a mix of optional and essential services. If an
6918 essential adaptation fails (or the failure cannot be bypassed for
6919 other reasons), the master transaction fails. Otherwise, the failure
6920 is bypassed as if the failed adaptation service was not in the chain.
6922 See also: adaptation_access adaptation_service_set
6925 adaptation_service_chain svcRequest requestLogger urlFilter leakDetector
6928 NAME: adaptation_access
6929 TYPE: adaptation_access_type
6930 IFDEF: USE_ADAPTATION
6934 Sends an HTTP transaction to an ICAP or eCAP adaptation service.
6936 adaptation_access service_name allow|deny [!]aclname...
6937 adaptation_access set_name allow|deny [!]aclname...
6939 At each supported vectoring point, the adaptation_access
6940 statements are processed in the order they appear in this
6941 configuration file. Statements pointing to the following services
6942 are ignored (i.e., skipped without checking their ACL):
6944 - services serving different vectoring points
6945 - "broken-but-bypassable" services
6946 - "up" services configured to ignore such transactions
6947 (e.g., based on the ICAP Transfer-Ignore header).
6949 When a set_name is used, all services in the set are checked
6950 using the same rules, to find the first applicable one. See
6951 adaptation_service_set for details.
6953 If an access list is checked and there is a match, the
6954 processing stops: For an "allow" rule, the corresponding
6955 adaptation service is used for the transaction. For a "deny"
6956 rule, no adaptation service is activated.
6958 It is currently not possible to apply more than one adaptation
6959 service at the same vectoring point to the same HTTP transaction.
6961 See also: icap_service and ecap_service
6964 adaptation_access service_1 allow all
6967 NAME: adaptation_service_iteration_limit
6969 IFDEF: USE_ADAPTATION
6970 LOC: Adaptation::Config::service_iteration_limit
6973 Limits the number of iterations allowed when applying adaptation
6974 services to a message. If your longest adaptation set or chain
6975 may have more than 16 services, increase the limit beyond its
6976 default value of 16. If detecting infinite iteration loops sooner
6977 is critical, make the iteration limit match the actual number
6978 of services in your longest adaptation set or chain.
6980 Infinite adaptation loops are most likely with routing services.
6982 See also: icap_service routing=1
6985 NAME: adaptation_masterx_shared_names
6987 IFDEF: USE_ADAPTATION
6988 LOC: Adaptation::Config::masterx_shared_name
6991 For each master transaction (i.e., the HTTP request and response
6992 sequence, including all related ICAP and eCAP exchanges), Squid
6993 maintains a table of metadata. The table entries are (name, value)
6994 pairs shared among eCAP and ICAP exchanges. The table is destroyed
6995 with the master transaction.
6997 This option specifies the table entry names that Squid must accept
6998 from and forward to the adaptation transactions.
7000 An ICAP REQMOD or RESPMOD transaction may set an entry in the
7001 shared table by returning an ICAP header field with a name
7002 specified in adaptation_masterx_shared_names.
7004 An eCAP REQMOD or RESPMOD transaction may set an entry in the
7005 shared table by implementing the libecap::visitEachOption() API
7006 to provide an option with a name specified in
7007 adaptation_masterx_shared_names.
7009 Squid will store and forward the set entry to subsequent adaptation
7010 transactions within the same master transaction scope.
7012 Only one shared entry name is supported at this time.
7015 # share authentication information among ICAP services
7016 adaptation_masterx_shared_names X-Subscriber-ID
7022 LOC: Adaptation::Icap::TheConfig.repeat
7023 DEFAULT_IF_NONE: deny all
7025 This ACL determines which retriable ICAP transactions are
7026 retried. Transactions that received a complete ICAP response
7027 and did not have to consume or produce HTTP bodies to receive
7028 that response are usually retriable.
7030 icap_retry allow|deny [!]aclname ...
7032 Squid automatically retries some ICAP I/O timeouts and errors
7033 due to persistent connection race conditions.
7035 See also: icap_retry_limit
7038 NAME: icap_retry_limit
7041 LOC: Adaptation::Icap::TheConfig.repeat_limit
7044 Limits the number of retries allowed. When set to zero (default),
7045 no retries are allowed.
7047 Communication errors due to persistent connection race
7048 conditions are unavoidable, automatically retried, and do not
7049 count against this limit.
7051 See also: icap_retry
7057 -----------------------------------------------------------------------------
7060 NAME: check_hostnames
7063 LOC: Config.onoff.check_hostnames
7065 For security and stability reasons Squid can check
7066 hostnames for Internet standard RFC compliance. If you want
7067 Squid to perform these checks turn this directive on.
7070 NAME: allow_underscore
7073 LOC: Config.onoff.allow_underscore
7075 Underscore characters is not strictly allowed in Internet hostnames
7076 but nevertheless used by many sites. Set this to off if you want
7077 Squid to be strict about the standard.
7078 This check is performed only when check_hostnames is set to on.
7081 NAME: cache_dns_program
7083 IFDEF: USE_DNSSERVERS
7084 DEFAULT: @DEFAULT_DNSSERVER@
7085 LOC: Config.Program.dnsserver
7087 Specify the location of the executable for dnslookup process.
7091 TYPE: HelperChildConfig
7092 IFDEF: USE_DNSSERVERS
7093 DEFAULT: 32 startup=1 idle=1
7094 LOC: Config.dnsChildren
7096 The maximum number of processes spawn to service DNS name lookups.
7097 If you limit it too few Squid will have to wait for them to process
7098 a backlog of requests, slowing it down. If you allow too many they
7099 will use RAM and other system resources noticably.
7100 The maximum this may be safely set to is 32.
7102 The startup= and idle= options allow some measure of skew in your
7107 Sets a minimum of how many processes are to be spawned when Squid
7108 starts or reconfigures. When set to zero the first request will
7109 cause spawning of the first child process to handle it.
7111 Starting too few will cause an initial slowdown in traffic as Squid
7112 attempts to simultaneously spawn enough processes to cope.
7116 Sets a minimum of how many processes Squid is to try and keep available
7117 at all times. When traffic begins to rise above what the existing
7118 processes can handle this many more will be spawned up to the maximum
7119 configured. A minimum setting of 1 is required.
7122 NAME: dns_retransmit_interval
7125 LOC: Config.Timeout.idns_retransmit
7126 IFDEF: !USE_DNSSERVERS
7128 Initial retransmit interval for DNS queries. The interval is
7129 doubled each time all configured DNS servers have been tried.
7135 LOC: Config.Timeout.idns_query
7136 IFDEF: !USE_DNSSERVERS
7138 DNS Query timeout. If no response is received to a DNS query
7139 within this time all DNS servers for the queried domain
7140 are assumed to be unavailable.
7143 NAME: dns_packet_max
7146 LOC: Config.dns.packet_max
7147 IFDEF: !USE_DNSSERVERS
7149 Maximum number of bytes packet size to advertise via EDNS.
7150 Set to "none" to disable EDNS large packet support.
7152 For legacy reasons DNS UDP replies will default to 512 bytes which
7153 is too small for many responses. EDNS provides a means for Squid to
7154 negotiate receiving larger responses back immediately without having
7155 to failover with repeat requests. Responses larger than this limit
7156 will retain the old behaviour of failover to TCP DNS.
7158 Squid has no real fixed limit internally, but allowing packet sizes
7159 over 1500 bytes requires network jumbogram support and is usually not
7162 WARNING: The RFC also indicates that some older resolvers will reply
7163 with failure of the whole request if the extension is added. Some
7164 resolvers have already been identified which will reply with mangled
7165 EDNS response on occasion. Usually in response to many-KB jumbogram
7166 sizes being advertised by Squid.
7167 Squid will currently treat these both as an unable-to-resolve domain
7168 even if it would be resolvable without EDNS.
7175 LOC: Config.onoff.res_defnames
7177 Normally the RES_DEFNAMES resolver option is disabled
7178 (see res_init(3)). This prevents caches in a hierarchy
7179 from interpreting single-component hostnames locally. To allow
7180 Squid to handle single-component names, enable this option.
7183 NAME: dns_nameservers
7186 LOC: Config.dns_nameservers
7188 Use this if you want to specify a list of DNS name servers
7189 (IP addresses) to use instead of those given in your
7190 /etc/resolv.conf file.
7191 On Windows platforms, if no value is specified here or in
7192 the /etc/resolv.conf file, the list of DNS name servers are
7193 taken from the Windows registry, both static and dynamic DHCP
7194 configurations are supported.
7196 Example: dns_nameservers 10.0.0.1 192.172.0.4
7201 DEFAULT: @DEFAULT_HOSTS@
7202 LOC: Config.etcHostsPath
7204 Location of the host-local IP name-address associations
7205 database. Most Operating Systems have such a file on different
7207 - Un*X & Linux: /etc/hosts
7208 - Windows NT/2000: %SystemRoot%\system32\drivers\etc\hosts
7209 (%SystemRoot% value install default is c:\winnt)
7210 - Windows XP/2003: %SystemRoot%\system32\drivers\etc\hosts
7211 (%SystemRoot% value install default is c:\windows)
7212 - Windows 9x/Me: %windir%\hosts
7213 (%windir% value is usually c:\windows)
7214 - Cygwin: /etc/hosts
7216 The file contains newline-separated definitions, in the
7217 form ip_address_in_dotted_form name [name ...] names are
7218 whitespace-separated. Lines beginning with an hash (#)
7219 character are comments.
7221 The file is checked at startup and upon configuration.
7222 If set to 'none', it won't be checked.
7223 If append_domain is used, that domain will be added to
7224 domain-local (i.e. not containing any dot character) host
7230 LOC: Config.appendDomain
7233 Appends local domain name to hostnames without any dots in
7234 them. append_domain must begin with a period.
7236 Be warned there are now Internet names with no dots in
7237 them using only top-domain names, so setting this may
7238 cause some Internet sites to become unavailable.
7241 append_domain .yourdomain.com
7244 NAME: ignore_unknown_nameservers
7246 LOC: Config.onoff.ignore_unknown_nameservers
7248 IFDEF: !USE_DNSSERVERS
7250 By default Squid checks that DNS responses are received
7251 from the same IP addresses they are sent to. If they
7252 don't match, Squid ignores the response and writes a warning
7253 message to cache.log. You can allow responses from unknown
7254 nameservers by setting this option to 'off'.
7257 NAME: dns_v4_fallback
7260 LOC: Config.onoff.dns_require_A
7261 IFDEF: !USE_DNSSERVERS
7263 Standard practice with DNS is to lookup either A or AAAA records
7264 and use the results if it succeeds. Only looking up the other if
7265 the first attempt fails or otherwise produces no results.
7267 That policy however will cause squid to produce error pages for some
7268 servers that advertise AAAA but are unreachable over IPv6.
7270 If this is ON squid will always lookup both AAAA and A, using both.
7271 If this is OFF squid will lookup AAAA and only try A if none found.
7273 WARNING: There are some possibly unwanted side-effects with this on:
7274 *) Doubles the load placed by squid on the DNS network.
7275 *) May negatively impact connection delay times.
7281 LOC: Config.dns.v4_first
7282 IFDEF: !USE_DNSSERVERS
7284 With the IPv6 Internet being as fast or faster than IPv4 Internet
7285 for most networks Squid prefers to contact websites over IPv6.
7287 This option reverses the order of preference to make Squid contact
7288 dual-stack websites over IPv4 first. Squid will still perform both
7289 IPv6 and IPv4 DNS lookups before connecting.
7292 This option will restrict the situations under which IPv6
7293 connectivity is used (and tested). Hiding network problems
7294 which would otherwise be detected and warned about.
7298 COMMENT: (number of entries)
7301 LOC: Config.ipcache.size
7308 LOC: Config.ipcache.low
7315 LOC: Config.ipcache.high
7317 The size, low-, and high-water marks for the IP cache.
7320 NAME: fqdncache_size
7321 COMMENT: (number of entries)
7324 LOC: Config.fqdncache.size
7326 Maximum number of FQDN cache entries.
7331 -----------------------------------------------------------------------------
7338 LOC: Config.onoff.mem_pools
7340 If set, Squid will keep pools of allocated (but unused) memory
7341 available for future use. If memory is a premium on your
7342 system and you believe your malloc library outperforms Squid
7343 routines, disable this.
7346 NAME: memory_pools_limit
7350 LOC: Config.MemPools.limit
7352 Used only with memory_pools on:
7353 memory_pools_limit 50 MB
7355 If set to a non-zero value, Squid will keep at most the specified
7356 limit of allocated (but unused) memory in memory pools. All free()
7357 requests that exceed this limit will be handled by your malloc
7358 library. Squid does not pre-allocate any memory, just safe-keeps
7359 objects that otherwise would be free()d. Thus, it is safe to set
7360 memory_pools_limit to a reasonably high value even if your
7361 configuration will use less memory.
7363 If set to none, Squid will keep all memory it can. That is, there
7364 will be no limit on the total amount of memory used for safe-keeping.
7366 To disable memory allocation optimization, do not set
7367 memory_pools_limit to 0 or none. Set memory_pools to "off" instead.
7369 An overhead for maintaining memory pools is not taken into account
7370 when the limit is checked. This overhead is close to four bytes per
7371 object kept. However, pools may actually _save_ memory because of
7372 reduced memory thrashing in your malloc library.
7376 COMMENT: on|off|transparent|truncate|delete
7379 LOC: opt_forwarded_for
7381 If set to "on", Squid will append your client's IP address
7382 in the HTTP requests it forwards. By default it looks like:
7384 X-Forwarded-For: 192.1.2.3
7386 If set to "off", it will appear as
7388 X-Forwarded-For: unknown
7390 If set to "transparent", Squid will not alter the
7391 X-Forwarded-For header in any way.
7393 If set to "delete", Squid will delete the entire
7394 X-Forwarded-For header.
7396 If set to "truncate", Squid will remove all existing
7397 X-Forwarded-For entries, and place the client IP as the sole entry.
7400 NAME: cachemgr_passwd
7401 TYPE: cachemgrpasswd
7403 LOC: Config.passwd_list
7405 Specify passwords for cachemgr operations.
7407 Usage: cachemgr_passwd password action action ...
7409 Some valid actions are (see cache manager menu for a full list):
7449 * Indicates actions which will not be performed without a
7450 valid password, others can be performed if not listed here.
7452 To disable an action, set the password to "disable".
7453 To allow performing an action without a password, set the
7456 Use the keyword "all" to set the same password for all actions.
7459 cachemgr_passwd secret shutdown
7460 cachemgr_passwd lesssssssecret info stats/objects
7461 cachemgr_passwd disable all
7468 LOC: Config.onoff.client_db
7470 If you want to disable collecting per-client statistics,
7471 turn off client_db here.
7474 NAME: refresh_all_ims
7478 LOC: Config.onoff.refresh_all_ims
7480 When you enable this option, squid will always check
7481 the origin server for an update when a client sends an
7482 If-Modified-Since request. Many browsers use IMS
7483 requests when the user requests a reload, and this
7484 ensures those clients receive the latest version.
7486 By default (off), squid may return a Not Modified response
7487 based on the age of the cached version.
7490 NAME: reload_into_ims
7491 IFDEF: USE_HTTP_VIOLATIONS
7495 LOC: Config.onoff.reload_into_ims
7497 When you enable this option, client no-cache or ``reload''
7498 requests will be changed to If-Modified-Since requests.
7499 Doing this VIOLATES the HTTP standard. Enabling this
7500 feature could make you liable for problems which it
7503 see also refresh_pattern for a more selective approach.
7506 NAME: connect_retries
7508 LOC: Config.connect_retries
7511 This sets the maximum number of connection attempts made for each
7512 TCP connection. The connect_retries attempts must all still
7513 complete within the connection timeout period.
7515 The default is not to re-try if the first connection attempt fails.
7516 The (not recommended) maximum is 10 tries.
7518 A warning message will be generated if it is set to a too-high
7519 value and the configured value will be over-ridden.
7521 Note: These re-tries are in addition to forward_max_tries
7522 which limit how many different addresses may be tried to find
7526 NAME: retry_on_error
7528 LOC: Config.retry.onerror
7531 If set to ON Squid will automatically retry requests when
7532 receiving an error response with status 403 (Forbidden),
7533 500 (Internal Error), 501 or 503 (Service not available).
7534 Status 502 and 504 (Gateway errors) are always retried.
7536 This is mainly useful if you are in a complex cache hierarchy to
7537 work around access control errors.
7539 NOTE: This retry will attempt to find another working destination.
7540 Which is different from the server which just failed.
7543 NAME: as_whois_server
7545 LOC: Config.as_whois_server
7546 DEFAULT: whois.ra.net
7548 WHOIS server to query for AS numbers. NOTE: AS numbers are
7549 queried only when Squid starts up, not for every request.
7554 LOC: Config.onoff.offline
7557 Enable this option and Squid will never try to validate cached
7561 NAME: uri_whitespace
7562 TYPE: uri_whitespace
7563 LOC: Config.uri_whitespace
7566 What to do with requests that have whitespace characters in the
7569 strip: The whitespace characters are stripped out of the URL.
7570 This is the behavior recommended by RFC2396.
7571 deny: The request is denied. The user receives an "Invalid
7573 allow: The request is allowed and the URI is not changed. The
7574 whitespace characters remain in the URI. Note the
7575 whitespace is passed to redirector processes if they
7577 encode: The request is allowed and the whitespace characters are
7578 encoded according to RFC1738. This could be considered
7579 a violation of the HTTP/1.1
7580 RFC because proxies are not allowed to rewrite URI's.
7581 chop: The request is allowed and the URI is chopped at the
7582 first whitespace. This might also be considered a
7588 LOC: Config.chroot_dir
7591 Specifies a directory where Squid should do a chroot() while
7592 initializing. This also causes Squid to fully drop root
7593 privileges after initializing. This means, for example, if you
7594 use a HTTP port less than 1024 and try to reconfigure, you may
7595 get an error saying that Squid can not open the port.
7598 NAME: balance_on_multiple_ip
7600 LOC: Config.onoff.balance_on_multiple_ip
7603 Modern IP resolvers in squid sort lookup results by preferred access.
7604 By default squid will use these IP in order and only rotates to
7605 the next listed when the most preffered fails.
7607 Some load balancing servers based on round robin DNS have been
7608 found not to preserve user session state across requests
7609 to different IP addresses.
7611 Enabling this directive Squid rotates IP's per request.
7614 NAME: pipeline_prefetch
7616 LOC: Config.onoff.pipeline_prefetch
7619 To boost the performance of pipelined requests to closer
7620 match that of a non-proxied environment Squid can try to fetch
7621 up to two requests in parallel from a pipeline.
7623 Defaults to off for bandwidth management and access logging
7626 WARNING: pipelining breaks NTLM and Negotiate/Kerberos authentication.
7629 NAME: high_response_time_warning
7632 LOC: Config.warnings.high_rptm
7635 If the one-minute median response time exceeds this value,
7636 Squid prints a WARNING with debug level 0 to get the
7637 administrators attention. The value is in milliseconds.
7640 NAME: high_page_fault_warning
7642 LOC: Config.warnings.high_pf
7645 If the one-minute average page fault rate exceeds this
7646 value, Squid prints a WARNING with debug level 0 to get
7647 the administrators attention. The value is in page faults
7651 NAME: high_memory_warning
7653 LOC: Config.warnings.high_memory
7656 If the memory usage (as determined by mallinfo) exceeds
7657 this amount, Squid prints a WARNING with debug level 0 to get
7658 the administrators attention.
7661 NAME: sleep_after_fork
7662 COMMENT: (microseconds)
7664 LOC: Config.sleep_after_fork
7667 When this is set to a non-zero value, the main Squid process
7668 sleeps the specified number of microseconds after a fork()
7669 system call. This sleep may help the situation where your
7670 system reports fork() failures due to lack of (virtual)
7671 memory. Note, however, if you have a lot of child
7672 processes, these sleep delays will add up and your
7673 Squid will not service requests for some amount of time
7674 until all the child processes have been started.
7675 On Windows value less then 1000 (1 milliseconds) are
7679 NAME: windows_ipaddrchangemonitor
7680 IFDEF: _SQUID_MSWIN_
7684 LOC: Config.onoff.WIN32_IpAddrChangeMonitor
7686 On Windows Squid by default will monitor IP address changes and will
7687 reconfigure itself after any detected event. This is very useful for
7688 proxies connected to internet with dial-up interfaces.
7689 In some cases (a Proxy server acting as VPN gateway is one) it could be
7690 desiderable to disable this behaviour setting this to 'off'.
7691 Note: after changing this, Squid service must be restarted.
7696 IFDEF: USE_SQUID_EUI
7698 LOC: Eui::TheConfig.euiLookup
7700 Whether to lookup the EUI or MAC address of a connected client.
7703 NAME: max_filedescriptors max_filedesc
7706 LOC: Config.max_filedescriptors
7708 The maximum number of filedescriptors supported.
7710 The default "0" means Squid inherits the current ulimit setting.
7712 Note: Changing this requires a restart of Squid. Also
7713 not all comm loops supports large values.
7721 Number of main Squid processes or "workers" to fork and maintain.
7722 0: "no daemon" mode, like running "squid -N ..."
7723 1: "no SMP" mode, start one main Squid process daemon (default)
7724 N: start N main Squid process daemons (i.e., SMP mode)
7726 In SMP mode, each worker does nearly all what a single Squid daemon
7727 does (e.g., listen on http_port and forward HTTP requests).
7730 NAME: cpu_affinity_map
7731 TYPE: CpuAffinityMap
7732 LOC: Config.cpuAffinityMap
7735 Usage: cpu_affinity_map process_numbers=P1,P2,... cores=C1,C2,...
7737 Sets 1:1 mapping between Squid processes and CPU cores. For example,
7739 cpu_affinity_map process_numbers=1,2,3,4 cores=1,3,5,7
7741 affects processes 1 through 4 only and places them on the first
7742 four even cores, starting with core #1.
7744 CPU cores are numbered starting from 1. Requires support for
7745 sched_getaffinity(2) and sched_setaffinity(2) system calls.
7747 Multiple cpu_affinity_map options are merged.
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