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.
636 Defining an Access List
638 Every access list definition must begin with an aclname and acltype,
639 followed by either type-specific arguments or a quoted filename that
642 acl aclname acltype argument ...
643 acl aclname acltype "file" ...
645 When using "file", the file should contain one item per line.
647 By default, regular expressions are CASE-SENSITIVE.
648 To make them case-insensitive, use the -i option. To return case-sensitive
649 use the +i option between patterns, or make a new ACL line without -i.
651 Some acl types require suspending the current request in order
652 to access some external data source.
653 Those which do are marked with the tag [slow], those which
654 don't are marked as [fast].
655 See http://wiki.squid-cache.org/SquidFaq/SquidAcl
656 for further information
658 ***** ACL TYPES AVAILABLE *****
660 acl aclname src ip-address/netmask ... # clients IP address [fast]
661 acl aclname src addr1-addr2/netmask ... # range of addresses [fast]
662 acl aclname dst ip-address/netmask ... # URL host's IP address [slow]
663 acl aclname myip ip-address/netmask ... # local socket IP address [fast]
665 acl aclname arp mac-address ... (xx:xx:xx:xx:xx:xx notation)
666 # The arp ACL requires the special configure option --enable-arp-acl.
667 # Furthermore, the ARP ACL code is not portable to all operating systems.
668 # It works on Linux, Solaris, Windows, FreeBSD, and some
669 # other *BSD variants.
672 # NOTE: Squid can only determine the MAC address for clients that are on
673 # the same subnet. If the client is on a different subnet,
674 # then Squid cannot find out its MAC address.
676 acl aclname srcdomain .foo.com ...
677 # reverse lookup, from client IP [slow]
678 acl aclname dstdomain .foo.com ...
679 # Destination server from URL [fast]
680 acl aclname srcdom_regex [-i] \.foo\.com ...
681 # regex matching client name [slow]
682 acl aclname dstdom_regex [-i] \.foo\.com ...
683 # regex matching server [fast]
685 # For dstdomain and dstdom_regex a reverse lookup is tried if a IP
686 # based URL is used and no match is found. The name "none" is used
687 # if the reverse lookup fails.
689 acl aclname src_as number ...
690 acl aclname dst_as number ...
692 # Except for access control, AS numbers can be used for
693 # routing of requests to specific caches. Here's an
694 # example for routing all requests for AS#1241 and only
695 # those to mycache.mydomain.net:
696 # acl asexample dst_as 1241
697 # cache_peer_access mycache.mydomain.net allow asexample
698 # cache_peer_access mycache_mydomain.net deny all
700 acl aclname peername myPeer ...
702 # match against a named cache_peer entry
703 # set unique name= on cache_peer lines for reliable use.
705 acl aclname time [day-abbrevs] [h1:m1-h2:m2]
715 # h1:m1 must be less than h2:m2
717 acl aclname url_regex [-i] ^http:// ...
718 # regex matching on whole URL [fast]
719 acl aclname urlpath_regex [-i] \.gif$ ...
720 # regex matching on URL path [fast]
722 acl aclname port 80 70 21 0-1024... # destination TCP port [fast]
724 acl aclname myport 3128 ... # local socket TCP port [fast]
725 acl aclname myportname 3128 ... # http(s)_port name [fast]
727 acl aclname proto HTTP FTP ... # request protocol [fast]
729 acl aclname method GET POST ... # HTTP request method [fast]
731 acl aclname http_status 200 301 500- 400-403 ...
732 # status code in reply [fast]
734 acl aclname browser [-i] regexp ...
735 # pattern match on User-Agent header (see also req_header below) [fast]
737 acl aclname referer_regex [-i] regexp ...
738 # pattern match on Referer header [fast]
739 # Referer is highly unreliable, so use with care
741 acl aclname ident username ...
742 acl aclname ident_regex [-i] pattern ...
743 # string match on ident output [slow]
744 # use REQUIRED to accept any non-null ident.
746 acl aclname proxy_auth [-i] username ...
747 acl aclname proxy_auth_regex [-i] pattern ...
748 # perform http authentication challenge to the client and match against
749 # supplied credentials [slow]
751 # takes a list of allowed usernames.
752 # use REQUIRED to accept any valid username.
754 # Will use proxy authentication in forward-proxy scenarios, and plain
755 # http authenticaiton in reverse-proxy scenarios
757 # NOTE: when a Proxy-Authentication header is sent but it is not
758 # needed during ACL checking the username is NOT logged
761 # NOTE: proxy_auth requires a EXTERNAL authentication program
762 # to check username/password combinations (see
763 # auth_param directive).
765 # NOTE: proxy_auth can't be used in a transparent/intercepting proxy
766 # as the browser needs to be configured for using a proxy in order
767 # to respond to proxy authentication.
769 acl aclname snmp_community string ...
770 # A community string to limit access to your SNMP Agent [fast]
773 # acl snmppublic snmp_community public
775 acl aclname maxconn number
776 # This will be matched when the client's IP address has
777 # more than <number> TCP connections established. [fast]
778 # NOTE: This only measures direct TCP links so X-Forwarded-For
779 # indirect clients are not counted.
781 acl aclname max_user_ip [-s] number
782 # This will be matched when the user attempts to log in from more
783 # than <number> different ip addresses. The authenticate_ip_ttl
784 # parameter controls the timeout on the ip entries. [fast]
785 # If -s is specified the limit is strict, denying browsing
786 # from any further IP addresses until the ttl has expired. Without
787 # -s Squid will just annoy the user by "randomly" denying requests.
788 # (the counter is reset each time the limit is reached and a
790 # NOTE: in acceleration mode or where there is mesh of child proxies,
791 # clients may appear to come from multiple addresses if they are
792 # going through proxy farms, so a limit of 1 may cause user problems.
794 acl aclname random probability
795 # Pseudo-randomly match requests. Based on the probability given.
796 # Probability may be written as a decimal (0.333), fraction (1/3)
797 # or ratio of matches:non-matches (3:5).
799 acl aclname req_mime_type [-i] mime-type ...
800 # regex match against the mime type of the request generated
801 # by the client. Can be used to detect file upload or some
802 # types HTTP tunneling requests [fast]
803 # NOTE: This does NOT match the reply. You cannot use this
804 # to match the returned file type.
806 acl aclname req_header header-name [-i] any\.regex\.here
807 # regex match against any of the known request headers. May be
808 # thought of as a superset of "browser", "referer" and "mime-type"
811 acl aclname rep_mime_type [-i] mime-type ...
812 # regex match against the mime type of the reply received by
813 # squid. Can be used to detect file download or some
814 # types HTTP tunneling requests. [fast]
815 # NOTE: This has no effect in http_access rules. It only has
816 # effect in rules that affect the reply data stream such as
819 acl aclname rep_header header-name [-i] any\.regex\.here
820 # regex match against any of the known reply headers. May be
821 # thought of as a superset of "browser", "referer" and "mime-type"
824 acl aclname external class_name [arguments...]
825 # external ACL lookup via a helper class defined by the
826 # external_acl_type directive [slow]
828 acl aclname user_cert attribute values...
829 # match against attributes in a user SSL certificate
830 # attribute is one of DN/C/O/CN/L/ST [fast]
832 acl aclname ca_cert attribute values...
833 # match against attributes a users issuing CA SSL certificate
834 # attribute is one of DN/C/O/CN/L/ST [fast]
836 acl aclname ext_user username ...
837 acl aclname ext_user_regex [-i] pattern ...
838 # string match on username returned by external acl helper [slow]
839 # use REQUIRED to accept any non-null user name.
841 acl aclname tag tagvalue ...
842 # string match on tag returned by external acl helper [slow]
844 acl aclname hier_code codename ...
845 # string match against squid hierarchy code(s); [fast]
846 # e.g., DIRECT, PARENT_HIT, NONE, etc.
848 # NOTE: This has no effect in http_access rules. It only has
849 # effect in rules that affect the reply data stream such as
853 acl macaddress arp 09:00:2b:23:45:67
854 acl myexample dst_as 1241
855 acl password proxy_auth REQUIRED
856 acl fileupload req_mime_type -i ^multipart/form-data$
857 acl javascript rep_mime_type -i ^application/x-javascript$
861 # Recommended minimum configuration:
863 acl manager proto cache_object
864 acl localhost src 127.0.0.1/32 ::1
865 acl to_localhost dst 127.0.0.0/8 0.0.0.0/32 ::1
867 # Example rule allowing access from your local networks.
868 # Adapt to list your (internal) IP networks from where browsing
870 acl localnet src 10.0.0.0/8 # RFC1918 possible internal network
871 acl localnet src 172.16.0.0/12 # RFC1918 possible internal network
872 acl localnet src 192.168.0.0/16 # RFC1918 possible internal network
873 acl localnet src fc00::/7 # RFC 4193 local private network range
874 acl localnet src fe80::/10 # RFC 4291 link-local (directly plugged) machines
876 acl SSL_ports port 443
877 acl Safe_ports port 80 # http
878 acl Safe_ports port 21 # ftp
879 acl Safe_ports port 443 # https
880 acl Safe_ports port 70 # gopher
881 acl Safe_ports port 210 # wais
882 acl Safe_ports port 1025-65535 # unregistered ports
883 acl Safe_ports port 280 # http-mgmt
884 acl Safe_ports port 488 # gss-http
885 acl Safe_ports port 591 # filemaker
886 acl Safe_ports port 777 # multiling http
887 acl CONNECT method CONNECT
891 NAME: follow_x_forwarded_for
893 IFDEF: FOLLOW_X_FORWARDED_FOR
894 LOC: Config.accessList.followXFF
895 DEFAULT_IF_NONE: deny all
897 Allowing or Denying the X-Forwarded-For header to be followed to
898 find the original source of a request.
900 Requests may pass through a chain of several other proxies
901 before reaching us. The X-Forwarded-For header will contain a
902 comma-separated list of the IP addresses in the chain, with the
903 rightmost address being the most recent.
905 If a request reaches us from a source that is allowed by this
906 configuration item, then we consult the X-Forwarded-For header
907 to see where that host received the request from. If the
908 X-Forwarded-For header contains multiple addresses, we continue
909 backtracking until we reach an address for which we are not allowed
910 to follow the X-Forwarded-For header, or until we reach the first
911 address in the list. For the purpose of ACL used in the
912 follow_x_forwarded_for directive the src ACL type always matches
913 the address we are testing and srcdomain matches its rDNS.
915 The end result of this process is an IP address that we will
916 refer to as the indirect client address. This address may
917 be treated as the client address for access control, ICAP, delay
918 pools and logging, depending on the acl_uses_indirect_client,
919 icap_uses_indirect_client, delay_pool_uses_indirect_client,
920 log_uses_indirect_client and tproxy_uses_indirect_client options.
922 This clause only supports fast acl types.
923 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
925 SECURITY CONSIDERATIONS:
927 Any host for which we follow the X-Forwarded-For header
928 can place incorrect information in the header, and Squid
929 will use the incorrect information as if it were the
930 source address of the request. This may enable remote
931 hosts to bypass any access control restrictions that are
932 based on the client's source addresses.
936 acl localhost src 127.0.0.1
937 acl my_other_proxy srcdomain .proxy.example.com
938 follow_x_forwarded_for allow localhost
939 follow_x_forwarded_for allow my_other_proxy
942 NAME: acl_uses_indirect_client
945 IFDEF: FOLLOW_X_FORWARDED_FOR
947 LOC: Config.onoff.acl_uses_indirect_client
949 Controls whether the indirect client address
950 (see follow_x_forwarded_for) is used instead of the
951 direct client address in acl matching.
953 NOTE: maxconn ACL considers direct TCP links and indirect
954 clients will always have zero. So no match.
957 NAME: delay_pool_uses_indirect_client
960 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_DELAY_POOLS
962 LOC: Config.onoff.delay_pool_uses_indirect_client
964 Controls whether the indirect client address
965 (see follow_x_forwarded_for) is used instead of the
966 direct client address in delay pools.
969 NAME: log_uses_indirect_client
972 IFDEF: FOLLOW_X_FORWARDED_FOR
974 LOC: Config.onoff.log_uses_indirect_client
976 Controls whether the indirect client address
977 (see follow_x_forwarded_for) is used instead of the
978 direct client address in the access log.
981 NAME: tproxy_uses_indirect_client
984 IFDEF: FOLLOW_X_FORWARDED_FOR&&LINUX_NETFILTER
986 LOC: Config.onoff.tproxy_uses_indirect_client
988 Controls whether the indirect client address
989 (see follow_x_forwarded_for) is used instead of the
990 direct client address when spoofing the outgoing client.
992 This has no effect on requests arriving in non-tproxy
995 SECURITY WARNING: Usage of this option is dangerous
996 and should not be used trivially. Correct configuration
997 of folow_x_forewarded_for with a limited set of trusted
998 sources is required to prevent abuse of your proxy.
1003 LOC: Config.accessList.http
1004 DEFAULT_IF_NONE: deny all
1006 Allowing or Denying access based on defined access lists
1008 Access to the HTTP port:
1009 http_access allow|deny [!]aclname ...
1011 NOTE on default values:
1013 If there are no "access" lines present, the default is to deny
1016 If none of the "access" lines cause a match, the default is the
1017 opposite of the last line in the list. If the last line was
1018 deny, the default is allow. Conversely, if the last line
1019 is allow, the default will be deny. For these reasons, it is a
1020 good idea to have an "deny all" entry at the end of your access
1021 lists to avoid potential confusion.
1023 This clause supports both fast and slow acl types.
1024 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1029 # Recommended minimum Access Permission configuration:
1031 # Only allow cachemgr access from localhost
1032 http_access allow manager localhost
1033 http_access deny manager
1035 # Deny requests to certain unsafe ports
1036 http_access deny !Safe_ports
1038 # Deny CONNECT to other than secure SSL ports
1039 http_access deny CONNECT !SSL_ports
1041 # We strongly recommend the following be uncommented to protect innocent
1042 # web applications running on the proxy server who think the only
1043 # one who can access services on "localhost" is a local user
1044 #http_access deny to_localhost
1047 # INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS
1050 # Example rule allowing access from your local networks.
1051 # Adapt localnet in the ACL section to list your (internal) IP networks
1052 # from where browsing should be allowed
1053 http_access allow localnet
1054 http_access allow localhost
1056 # And finally deny all other access to this proxy
1057 http_access deny all
1061 NAME: adapted_http_access http_access2
1063 LOC: Config.accessList.adapted_http
1066 Allowing or Denying access based on defined access lists
1068 Essentially identical to http_access, but runs after redirectors
1069 and ICAP/eCAP adaptation. Allowing access control based on their
1072 If not set then only http_access is used.
1075 NAME: http_reply_access
1077 LOC: Config.accessList.reply
1080 Allow replies to client requests. This is complementary to http_access.
1082 http_reply_access allow|deny [!] aclname ...
1084 NOTE: if there are no access lines present, the default is to allow
1087 If none of the access lines cause a match the opposite of the
1088 last line will apply. Thus it is good practice to end the rules
1089 with an "allow all" or "deny all" entry.
1091 This clause supports both fast and slow acl types.
1092 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1097 LOC: Config.accessList.icp
1098 DEFAULT_IF_NONE: deny all
1100 Allowing or Denying access to the ICP port based on defined
1103 icp_access allow|deny [!]aclname ...
1105 See http_access for details
1107 This clause only supports fast acl types.
1108 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1110 # Allow ICP queries from local networks only
1111 #icp_access allow localnet
1112 #icp_access deny all
1118 LOC: Config.accessList.htcp
1119 DEFAULT_IF_NONE: deny all
1121 Allowing or Denying access to the HTCP port based on defined
1124 htcp_access allow|deny [!]aclname ...
1126 See http_access for details
1128 NOTE: The default if no htcp_access lines are present is to
1129 deny all traffic. This default may cause problems with peers
1130 using the htcp option.
1132 This clause only supports fast acl types.
1133 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1135 # Allow HTCP queries from local networks only
1136 #htcp_access allow localnet
1137 #htcp_access deny all
1140 NAME: htcp_clr_access
1143 LOC: Config.accessList.htcp_clr
1144 DEFAULT_IF_NONE: deny all
1146 Allowing or Denying access to purge content using HTCP based
1147 on defined access lists
1149 htcp_clr_access allow|deny [!]aclname ...
1151 See http_access for details
1153 This clause only supports fast acl types.
1154 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1156 # Allow HTCP CLR requests from trusted peers
1157 acl htcp_clr_peer src 172.16.1.2
1158 htcp_clr_access allow htcp_clr_peer
1163 LOC: Config.accessList.miss
1166 Use to force your neighbors to use you as a sibling instead of
1167 a parent. For example:
1169 acl localclients src 172.16.0.0/16
1170 miss_access allow localclients
1171 miss_access deny !localclients
1173 This means only your local clients are allowed to fetch
1174 MISSES and all other clients can only fetch HITS.
1176 By default, allow all clients who passed the http_access rules
1177 to fetch MISSES from us.
1179 This clause only supports fast acl types.
1180 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1183 NAME: ident_lookup_access
1186 DEFAULT_IF_NONE: deny all
1187 LOC: Ident::TheConfig.identLookup
1189 A list of ACL elements which, if matched, cause an ident
1190 (RFC 931) lookup to be performed for this request. For
1191 example, you might choose to always perform ident lookups
1192 for your main multi-user Unix boxes, but not for your Macs
1193 and PCs. By default, ident lookups are not performed for
1196 To enable ident lookups for specific client addresses, you
1197 can follow this example:
1199 acl ident_aware_hosts src 198.168.1.0/24
1200 ident_lookup_access allow ident_aware_hosts
1201 ident_lookup_access deny all
1203 Only src type ACL checks are fully supported. A srcdomain
1204 ACL might work at times, but it will not always provide
1207 This clause only supports fast acl types.
1208 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1211 NAME: reply_body_max_size
1212 COMMENT: size [acl acl...]
1215 LOC: Config.ReplyBodySize
1217 This option specifies the maximum size of a reply body. It can be
1218 used to prevent users from downloading very large files, such as
1219 MP3's and movies. When the reply headers are received, the
1220 reply_body_max_size lines are processed, and the first line where
1221 all (if any) listed ACLs are true is used as the maximum body size
1224 This size is checked twice. First when we get the reply headers,
1225 we check the content-length value. If the content length value exists
1226 and is larger than the allowed size, the request is denied and the
1227 user receives an error message that says "the request or reply
1228 is too large." If there is no content-length, and the reply
1229 size exceeds this limit, the client's connection is just closed
1230 and they will receive a partial reply.
1232 WARNING: downstream caches probably can not detect a partial reply
1233 if there is no content-length header, so they will cache
1234 partial responses and give them out as hits. You should NOT
1235 use this option if you have downstream caches.
1237 WARNING: A maximum size smaller than the size of squid's error messages
1238 will cause an infinite loop and crash squid. Ensure that the smallest
1239 non-zero value you use is greater that the maximum header size plus
1240 the size of your largest error page.
1242 If you set this parameter none (the default), there will be
1245 Configuration Format is:
1246 reply_body_max_size SIZE UNITS [acl ...]
1248 reply_body_max_size 10 MB
1254 -----------------------------------------------------------------------------
1257 NAME: http_port ascii_port
1258 TYPE: http_port_list
1260 LOC: Config.Sockaddr.http
1262 Usage: port [mode] [options]
1263 hostname:port [mode] [options]
1264 1.2.3.4:port [mode] [options]
1266 The socket addresses where Squid will listen for HTTP client
1267 requests. You may specify multiple socket addresses.
1268 There are three forms: port alone, hostname with port, and
1269 IP address with port. If you specify a hostname or IP
1270 address, Squid binds the socket to that specific
1271 address. Most likely, you do not need to bind to a specific
1272 address, so you can use the port number alone.
1274 If you are running Squid in accelerator mode, you
1275 probably want to listen on port 80 also, or instead.
1277 The -a command line option may be used to specify additional
1278 port(s) where Squid listens for proxy request. Such ports will
1279 be plain proxy ports with no options.
1281 You may specify multiple socket addresses on multiple lines.
1285 intercept Support for IP-Layer interception of
1286 outgoing requests without browser settings.
1287 NP: disables authentication and IPv6 on the port.
1289 tproxy Support Linux TPROXY for spoofing outgoing
1290 connections using the client IP address.
1291 NP: disables authentication and maybe IPv6 on the port.
1293 accel Accelerator mode. Also needs at least one of
1294 vhost / vport / defaultsite.
1296 ssl-bump Intercept each CONNECT request matching ssl_bump ACL,
1297 establish secure connection with the client and with
1298 the server, decrypt HTTP messages as they pass through
1299 Squid, and treat them as unencrypted HTTP messages,
1300 becoming the man-in-the-middle.
1302 The ssl_bump option is required to fully enable
1303 the SslBump feature.
1305 Omitting the mode flag causes default forward proxy mode to be used.
1308 Accelerator Mode Options:
1310 allow-direct Allow direct forwarding in accelerator mode. Normally
1311 accelerated requests are denied direct forwarding as if
1312 never_direct was used.
1314 defaultsite=domainname
1315 What to use for the Host: header if it is not present
1316 in a request. Determines what site (not origin server)
1317 accelerators should consider the default.
1320 vhost Using the Host header for virtual domain support.
1321 Also uses the port as specified in Host: header.
1323 vport IP based virtual host support. Using the http_port number
1324 in passed on Host: headers.
1326 vport=NN Uses the specified port number rather than the
1329 protocol= Protocol to reconstruct accelerated requests with.
1330 Defaults to http://.
1332 ignore-cc Ignore request Cache-Control headers.
1334 Warning: This option violates HTTP specifications if
1335 used in non-accelerator setups.
1338 SSL Bump Mode Options:
1340 cert= Path to SSL certificate (PEM format).
1342 key= Path to SSL private key file (PEM format)
1343 if not specified, the certificate file is
1344 assumed to be a combined certificate and
1347 version= The version of SSL/TLS supported
1348 1 automatic (default)
1353 cipher= Colon separated list of supported ciphers.
1355 options= Various SSL engine options. The most important
1357 NO_SSLv2 Disallow the use of SSLv2
1358 NO_SSLv3 Disallow the use of SSLv3
1359 NO_TLSv1 Disallow the use of TLSv1
1360 SINGLE_DH_USE Always create a new key when using
1361 temporary/ephemeral DH key exchanges
1362 See src/ssl_support.c or OpenSSL SSL_CTX_set_options
1363 documentation for a complete list of options.
1365 clientca= File containing the list of CAs to use when
1366 requesting a client certificate.
1368 cafile= File containing additional CA certificates to
1369 use when verifying client certificates. If unset
1370 clientca will be used.
1372 capath= Directory containing additional CA certificates
1373 and CRL lists to use when verifying client certificates.
1375 crlfile= File of additional CRL lists to use when verifying
1376 the client certificate, in addition to CRLs stored in
1377 the capath. Implies VERIFY_CRL flag below.
1379 dhparams= File containing DH parameters for temporary/ephemeral
1382 sslflags= Various flags modifying the use of SSL:
1384 Don't request client certificates
1385 immediately, but wait until acl processing
1386 requires a certificate (not yet implemented).
1388 Don't use the default CA lists built in
1391 Don't allow for session reuse. Each connection
1392 will result in a new SSL session.
1394 Verify CRL lists when accepting client
1397 Verify CRL lists for all certificates in the
1398 client certificate chain.
1400 sslcontext= SSL session ID context identifier.
1402 generate-host-certificates[=<on|off>]
1403 Dynamically create SSL server certificates for the
1404 destination hosts of bumped CONNECT requests.When
1405 enabled, the cert and key options are used to sign
1406 generated certificates. Otherwise generated
1407 certificate will be selfsigned.
1408 If there is CA certificate life time of generated
1409 certificate equals lifetime of CA certificate. If
1410 generated certificate is selfsigned lifetime is three
1412 This option is enabled by default when SslBump is used.
1413 See the sslBump option above for more information.
1415 dynamic_cert_mem_cache_size=SIZE
1416 Approximate total RAM size spent on cached generated
1417 certificates. If set to zero, caching is disabled. The
1418 default value is 4MB. An average XXX-bit certificate
1419 consumes about XXX bytes of RAM.
1423 connection-auth[=on|off]
1424 use connection-auth=off to tell Squid to prevent
1425 forwarding Microsoft connection oriented authentication
1426 (NTLM, Negotiate and Kerberos)
1428 disable-pmtu-discovery=
1429 Control Path-MTU discovery usage:
1430 off lets OS decide on what to do (default).
1431 transparent disable PMTU discovery when transparent
1433 always disable always PMTU discovery.
1435 In many setups of transparently intercepting proxies
1436 Path-MTU discovery can not work on traffic towards the
1437 clients. This is the case when the intercepting device
1438 does not fully track connections and fails to forward
1439 ICMP must fragment messages to the cache server. If you
1440 have such setup and experience that certain clients
1441 sporadically hang or never complete requests set
1442 disable-pmtu-discovery option to 'transparent'.
1444 name= Specifies a internal name for the port. Defaults to
1445 the port specification (port or addr:port)
1447 tcpkeepalive[=idle,interval,timeout]
1448 Enable TCP keepalive probes of idle connections.
1449 In seconds; idle is the initial time before TCP starts
1450 probing the connection, interval how often to probe, and
1451 timeout the time before giving up.
1453 If you run Squid on a dual-homed machine with an internal
1454 and an external interface we recommend you to specify the
1455 internal address:port in http_port. This way Squid will only be
1456 visible on the internal address.
1460 # Squid normally listens to port 3128
1461 http_port @DEFAULT_HTTP_PORT@
1467 TYPE: https_port_list
1469 LOC: Config.Sockaddr.https
1471 Usage: [ip:]port cert=certificate.pem [key=key.pem] [options...]
1473 The socket address where Squid will listen for HTTPS client
1476 This is really only useful for situations where you are running
1477 squid in accelerator mode and you want to do the SSL work at the
1480 You may specify multiple socket addresses on multiple lines,
1481 each with their own SSL certificate and/or options.
1485 accel Accelerator mode. Also needs at least one of
1486 defaultsite or vhost.
1488 defaultsite= The name of the https site presented on
1489 this port. Implies accel.
1491 vhost Accelerator mode using Host header for virtual
1492 domain support. Requires a wildcard certificate
1493 or other certificate valid for more than one domain.
1496 protocol= Protocol to reconstruct accelerated requests with.
1499 cert= Path to SSL certificate (PEM format).
1501 key= Path to SSL private key file (PEM format)
1502 if not specified, the certificate file is
1503 assumed to be a combined certificate and
1506 version= The version of SSL/TLS supported
1507 1 automatic (default)
1512 cipher= Colon separated list of supported ciphers.
1514 options= Various SSL engine options. The most important
1516 NO_SSLv2 Disallow the use of SSLv2
1517 NO_SSLv3 Disallow the use of SSLv3
1518 NO_TLSv1 Disallow the use of TLSv1
1519 SINGLE_DH_USE Always create a new key when using
1520 temporary/ephemeral DH key exchanges
1521 See src/ssl_support.c or OpenSSL SSL_CTX_set_options
1522 documentation for a complete list of options.
1524 clientca= File containing the list of CAs to use when
1525 requesting a client certificate.
1527 cafile= File containing additional CA certificates to
1528 use when verifying client certificates. If unset
1529 clientca will be used.
1531 capath= Directory containing additional CA certificates
1532 and CRL lists to use when verifying client certificates.
1534 crlfile= File of additional CRL lists to use when verifying
1535 the client certificate, in addition to CRLs stored in
1536 the capath. Implies VERIFY_CRL flag below.
1538 dhparams= File containing DH parameters for temporary/ephemeral
1541 sslflags= Various flags modifying the use of SSL:
1543 Don't request client certificates
1544 immediately, but wait until acl processing
1545 requires a certificate (not yet implemented).
1547 Don't use the default CA lists built in
1550 Don't allow for session reuse. Each connection
1551 will result in a new SSL session.
1553 Verify CRL lists when accepting client
1556 Verify CRL lists for all certificates in the
1557 client certificate chain.
1559 sslcontext= SSL session ID context identifier.
1561 vport Accelerator with IP based virtual host support.
1563 vport=NN As above, but uses specified port number rather
1564 than the https_port number. Implies accel.
1566 name= Specifies a internal name for the port. Defaults to
1567 the port specification (port or addr:port)
1571 NAME: tcp_outgoing_tos tcp_outgoing_ds tcp_outgoing_dscp
1574 LOC: Ip::Qos::TheConfig.tosToServer
1576 Allows you to select a TOS/Diffserv value for packets outgoing
1577 on the server side, based on an ACL.
1579 tcp_outgoing_tos ds-field [!]aclname ...
1581 Example where normal_service_net uses the TOS value 0x00
1582 and good_service_net uses 0x20
1584 acl normal_service_net src 10.0.0.0/24
1585 acl good_service_net src 10.0.1.0/24
1586 tcp_outgoing_tos 0x00 normal_service_net
1587 tcp_outgoing_tos 0x20 good_service_net
1589 TOS/DSCP values really only have local significance - so you should
1590 know what you're specifying. For more information, see RFC2474,
1591 RFC2475, and RFC3260.
1593 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
1594 "default" to use whatever default your host has. Note that in
1595 practice often only multiples of 4 is usable as the two rightmost bits
1596 have been redefined for use by ECN (RFC 3168 section 23.1).
1598 Processing proceeds in the order specified, and stops at first fully
1602 NAME: clientside_tos
1605 LOC: Ip::Qos::TheConfig.tosToClient
1607 Allows you to select a TOS/Diffserv value for packets being transmitted
1608 on the client-side, based on an ACL.
1610 clientside_tos ds-field [!]aclname ...
1612 Example where normal_service_net uses the TOS value 0x00
1613 and good_service_net uses 0x20
1615 acl normal_service_net src 10.0.0.0/24
1616 acl good_service_net src 10.0.1.0/24
1617 clientside_tos 0x00 normal_service_net
1618 clientside_tos 0x20 good_service_net
1620 Note: This feature is incompatible with qos_flows. Any TOS values set here
1621 will be overwritten by TOS values in qos_flows.
1624 NAME: tcp_outgoing_mark
1626 IFDEF: SO_MARK&&USE_LIBCAP
1628 LOC: Ip::Qos::TheConfig.nfmarkToServer
1630 Allows you to apply a Netfilter mark value to outgoing packets
1631 on the server side, based on an ACL.
1633 tcp_outgoing_mark mark-value [!]aclname ...
1635 Example where normal_service_net uses the mark value 0x00
1636 and good_service_net uses 0x20
1638 acl normal_service_net src 10.0.0.0/24
1639 acl good_service_net src 10.0.1.0/24
1640 tcp_outgoing_mark 0x00 normal_service_net
1641 tcp_outgoing_mark 0x20 good_service_net
1644 NAME: clientside_mark
1646 IFDEF: SO_MARK&&USE_LIBCAP
1648 LOC: Ip::Qos::TheConfig.nfmarkToClient
1650 Allows you to apply a Netfilter mark value to packets being transmitted
1651 on the client-side, based on an ACL.
1653 clientside_mark mark-value [!]aclname ...
1655 Example where normal_service_net uses the mark value 0x00
1656 and good_service_net uses 0x20
1658 acl normal_service_net src 10.0.0.0/24
1659 acl good_service_net src 10.0.1.0/24
1660 clientside_mark 0x00 normal_service_net
1661 clientside_mark 0x20 good_service_net
1663 Note: This feature is incompatible with qos_flows. Any mark values set here
1664 will be overwritten by mark values in qos_flows.
1671 LOC: Ip::Qos::TheConfig
1673 Allows you to select a TOS/DSCP value to mark outgoing
1674 connections with, based on where the reply was sourced. For
1675 platforms using netfilter, allows you to set a netfilter mark
1676 value instead of, or in addition to, a TOS value.
1678 TOS values really only have local significance - so you should
1679 know what you're specifying. For more information, see RFC2474,
1680 RFC2475, and RFC3260.
1682 The TOS/DSCP byte must be exactly that - a octet value 0 - 255. Note that
1683 in practice often only multiples of 4 is usable as the two rightmost bits
1684 have been redefined for use by ECN (RFC 3168 section 23.1).
1686 Mark values can be any unsigned 32-bit integer value.
1688 This setting is configured by setting the following values:
1690 tos|mark Whether to set TOS or netfilter mark values
1692 local-hit=0xFF Value to mark local cache hits.
1694 sibling-hit=0xFF Value to mark hits from sibling peers.
1696 parent-hit=0xFF Value to mark hits from parent peers.
1698 miss=0xFF Value to mark cache misses. Takes precedence
1699 over the preserve-miss feature (see below).
1701 The TOS variant of the following features are only possible on Linux
1702 and require your kernel to be patched with the TOS preserving ZPH
1703 patch, available from http://zph.bratcheda.org
1704 No patch is needed to preserve the netfilter mark, which will work
1705 with all variants of netfilter.
1707 disable-preserve-miss
1708 This option disables the preservation of the TOS or netfilter
1709 mark. By default, the existing TOS or netfilter mark value of
1710 the response coming from the remote server will be retained
1711 and masked with miss-mark.
1712 NOTE: in the case of a netfilter mark, the mark must be set on
1713 the connection (using the CONNMARK target) not on the packet
1717 Allows you to mask certain bits in the TOS or mark value
1718 received from the remote server, before copying the value to
1719 the TOS sent towards clients.
1720 Default for tos: 0xFF (TOS from server is not changed).
1721 Default for mark: 0xFFFFFFFF (mark from server is not changed).
1723 All of these features require the --enable-zph-qos compilation flag
1724 (enabled by default). Netfilter marking also requires the
1725 libnetfilter_conntrack libraries (--with-netfilter-conntrack) and
1726 libcap 2.09+ (--with-libcap).
1730 NAME: tcp_outgoing_address
1733 LOC: Config.accessList.outgoing_address
1735 Allows you to map requests to different outgoing IP addresses
1736 based on the username or source address of the user making
1739 tcp_outgoing_address ipaddr [[!]aclname] ...
1741 Example where requests from 10.0.0.0/24 will be forwarded
1742 with source address 10.1.0.1, 10.0.2.0/24 forwarded with
1743 source address 10.1.0.2 and the rest will be forwarded with
1744 source address 10.1.0.3.
1746 acl normal_service_net src 10.0.0.0/24
1747 acl good_service_net src 10.0.2.0/24
1748 tcp_outgoing_address 10.1.0.1 normal_service_net
1749 tcp_outgoing_address 10.1.0.2 good_service_net
1750 tcp_outgoing_address 10.1.0.3
1752 Processing proceeds in the order specified, and stops at first fully
1755 Note: The use of this directive using client dependent ACLs is
1756 incompatible with the use of server side persistent connections. To
1757 ensure correct results it is best to set server_persistent_connections
1758 to off when using this directive in such configurations.
1760 Note: The use of this directive to set a local IP on outgoing TCP links
1761 is incompatible with using TPROXY to set client IP out outbound TCP links.
1762 When needing to contact peers use the no-tproxy cache_peer option to
1763 re-enable normal forwarding such as this.
1767 Squid is built with a capability of bridging the IPv4 and IPv6
1769 tcp_outgoing_address as exampled above breaks this bridging by forcing
1770 all outbound traffic through a certain IPv4 which may be on the wrong
1771 side of the IPv4/IPv6 boundary.
1773 To operate with tcp_outgoing_address and keep the bridging benefits
1774 an additional ACL needs to be used which ensures the IPv6-bound traffic
1775 is never forced or permitted out the IPv4 interface.
1777 # IPv6 destination test along with a dummy access control to perofrm the required DNS
1778 # This MUST be place before any ALLOW rules.
1779 acl to_ipv6 dst ipv6
1780 http_access deny ipv6 !all
1782 tcp_outgoing_address 2001:db8::c001 good_service_net to_ipv6
1783 tcp_outgoing_address 10.1.0.2 good_service_net !to_ipv6
1785 tcp_outgoing_address 2001:db8::beef normal_service_net to_ipv6
1786 tcp_outgoing_address 10.1.0.1 normal_service_net !to_ipv6
1788 tcp_outgoing_address 2001:db8::1 to_ipv6
1789 tcp_outgoing_address 10.1.0.3 !to_ipv6
1792 'dst ipv6' bases its selection assuming DIRECT access.
1793 If peers are used the peername ACL are needed to select outgoing
1794 address which can link to the peer.
1796 'dst ipv6' is a slow ACL. It will only work here if 'dst' is used
1797 previously in the http_access rules to locate the destination IP.
1798 Some more magic may be needed for that:
1799 http_access allow to_ipv6 !all
1800 (meaning, allow if to IPv6 but not from anywhere ;)
1806 -----------------------------------------------------------------------------
1809 NAME: ssl_unclean_shutdown
1813 LOC: Config.SSL.unclean_shutdown
1815 Some browsers (especially MSIE) bugs out on SSL shutdown
1822 LOC: Config.SSL.ssl_engine
1825 The OpenSSL engine to use. You will need to set this if you
1826 would like to use hardware SSL acceleration for example.
1829 NAME: sslproxy_client_certificate
1832 LOC: Config.ssl_client.cert
1835 Client SSL Certificate to use when proxying https:// URLs
1838 NAME: sslproxy_client_key
1841 LOC: Config.ssl_client.key
1844 Client SSL Key to use when proxying https:// URLs
1847 NAME: sslproxy_version
1850 LOC: Config.ssl_client.version
1853 SSL version level to use when proxying https:// URLs
1856 NAME: sslproxy_options
1859 LOC: Config.ssl_client.options
1862 SSL engine options to use when proxying https:// URLs
1864 The most important being:
1866 NO_SSLv2 Disallow the use of SSLv2
1867 NO_SSLv3 Disallow the use of SSLv3
1868 NO_TLSv1 Disallow the use of TLSv1
1870 Always create a new key when using
1871 temporary/ephemeral DH key exchanges
1873 These options vary depending on your SSL engine.
1874 See the OpenSSL SSL_CTX_set_options documentation for a
1875 complete list of possible options.
1878 NAME: sslproxy_cipher
1881 LOC: Config.ssl_client.cipher
1884 SSL cipher list to use when proxying https:// URLs
1886 Colon separated list of supported ciphers.
1889 NAME: sslproxy_cafile
1892 LOC: Config.ssl_client.cafile
1895 file containing CA certificates to use when verifying server
1896 certificates while proxying https:// URLs
1899 NAME: sslproxy_capath
1902 LOC: Config.ssl_client.capath
1905 directory containing CA certificates to use when verifying
1906 server certificates while proxying https:// URLs
1912 LOC: Config.accessList.ssl_bump
1915 This ACL controls which CONNECT requests to an http_port
1916 marked with an sslBump flag are actually "bumped". Please
1917 see the sslBump flag of an http_port option for more details
1918 about decoding proxied SSL connections.
1920 By default, no requests are bumped.
1922 See also: http_port ssl-bump
1924 This clause supports both fast and slow acl types.
1925 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1928 # Example: Bump all requests except those originating from localhost and
1929 # those going to webax.com or example.com sites.
1931 acl localhost src 127.0.0.1/32
1932 acl broken_sites dstdomain .webax.com
1933 acl broken_sites dstdomain .example.com
1934 ssl_bump deny localhost
1935 ssl_bump deny broken_sites
1939 NAME: sslproxy_flags
1942 LOC: Config.ssl_client.flags
1945 Various flags modifying the use of SSL while proxying https:// URLs:
1946 DONT_VERIFY_PEER Accept certificates that fail verification.
1947 For refined control, see sslproxy_cert_error.
1948 NO_DEFAULT_CA Don't use the default CA list built in
1952 NAME: sslproxy_cert_error
1955 LOC: Config.ssl_client.cert_error
1958 Use this ACL to bypass server certificate validation errors.
1960 For example, the following lines will bypass all validation errors
1961 when talking to servers located at 172.16.0.0/16. All other
1962 validation errors will result in ERR_SECURE_CONNECT_FAIL error.
1964 acl BrokenServersAtTrustedIP dst 172.16.0.0/16
1965 sslproxy_cert_error allow BrokenServersAtTrustedIP
1966 sslproxy_cert_error deny all
1968 This clause only supports fast acl types.
1969 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1970 Using slow acl types may result in server crashes
1972 Without this option, all server certificate validation errors
1973 terminate the transaction. Bypassing validation errors is dangerous
1974 because an error usually implies that the server cannot be trusted and
1975 the connection may be insecure.
1977 See also: sslproxy_flags and DONT_VERIFY_PEER.
1979 Default setting: sslproxy_cert_error deny all
1982 NAME: sslpassword_program
1985 LOC: Config.Program.ssl_password
1988 Specify a program used for entering SSL key passphrases
1989 when using encrypted SSL certificate keys. If not specified
1990 keys must either be unencrypted, or Squid started with the -N
1991 option to allow it to query interactively for the passphrase.
1993 The key file name is given as argument to the program allowing
1994 selection of the right password if you have multiple encrypted
1999 OPTIONS RELATING TO EXTERNAL SSL_CRTD
2000 -----------------------------------------------------------------------------
2003 NAME: sslcrtd_program
2006 DEFAULT: @DEFAULT_SSL_CRTD@ -s @DEFAULT_SSL_DB_DIR@ -M 4MB
2007 LOC: Ssl::TheConfig.ssl_crtd
2009 Specify the location and options of the executable for ssl_crtd process.
2010 @DEFAULT_SSL_CRTD@ program requires -s and -M parameters
2011 For more information use:
2012 @DEFAULT_SSL_CRTD@ -h
2015 NAME: sslcrtd_children
2016 TYPE: HelperChildConfig
2018 DEFAULT: 32 startup=5 idle=1
2019 LOC: Ssl::TheConfig.ssl_crtdChildren
2021 The maximum number of processes spawn to service ssl server.
2022 The maximum this may be safely set to is 32.
2024 The startup= and idle= options allow some measure of skew in your
2029 Sets the minimum number of processes to spawn when Squid
2030 starts or reconfigures. When set to zero the first request will
2031 cause spawning of the first child process to handle it.
2033 Starting too few children temporary slows Squid under load while it
2034 tries to spawn enough additional processes to cope with traffic.
2038 Sets a minimum of how many processes Squid is to try and keep available
2039 at all times. When traffic begins to rise above what the existing
2040 processes can handle this many more will be spawned up to the maximum
2041 configured. A minimum setting of 1 is required.
2043 You must have at least one ssl_crtd process.
2047 OPTIONS WHICH AFFECT THE NEIGHBOR SELECTION ALGORITHM
2048 -----------------------------------------------------------------------------
2056 To specify other caches in a hierarchy, use the format:
2058 cache_peer hostname type http-port icp-port [options]
2063 # hostname type port port options
2064 # -------------------- -------- ----- ----- -----------
2065 cache_peer parent.foo.net parent 3128 3130 default
2066 cache_peer sib1.foo.net sibling 3128 3130 proxy-only
2067 cache_peer sib2.foo.net sibling 3128 3130 proxy-only
2068 cache_peer example.com parent 80 0 no-query default
2069 cache_peer cdn.example.com sibling 3128 0
2071 type: either 'parent', 'sibling', or 'multicast'.
2073 proxy-port: The port number where the peer accept HTTP requests.
2074 For other Squid proxies this is usually 3128
2075 For web servers this is usually 80
2077 icp-port: Used for querying neighbor caches about objects.
2078 Set to 0 if the peer does not support ICP or HTCP.
2079 See ICP and HTCP options below for additional details.
2082 ==== ICP OPTIONS ====
2084 You MUST also set icp_port and icp_access explicitly when using these options.
2085 The defaults will prevent peer traffic using ICP.
2088 no-query Disable ICP queries to this neighbor.
2091 Indicates the named peer is a member of a multicast group.
2092 ICP queries will not be sent directly to the peer, but ICP
2093 replies will be accepted from it.
2095 closest-only Indicates that, for ICP_OP_MISS replies, we'll only forward
2096 CLOSEST_PARENT_MISSes and never FIRST_PARENT_MISSes.
2099 To only send ICP queries to this neighbor infrequently.
2100 This is used to keep the neighbor round trip time updated
2101 and is usually used in conjunction with weighted-round-robin.
2104 ==== HTCP OPTIONS ====
2106 You MUST also set htcp_port and htcp_access explicitly when using these options.
2107 The defaults will prevent peer traffic using HTCP.
2110 htcp Send HTCP, instead of ICP, queries to the neighbor.
2111 You probably also want to set the "icp-port" to 4827
2112 instead of 3130. This directive accepts a comma separated
2113 list of options described below.
2115 htcp=oldsquid Send HTCP to old Squid versions (2.5 or earlier).
2117 htcp=no-clr Send HTCP to the neighbor but without
2118 sending any CLR requests. This cannot be used with
2121 htcp=only-clr Send HTCP to the neighbor but ONLY CLR requests.
2122 This cannot be used with no-clr.
2125 Send HTCP to the neighbor including CLRs but only when
2126 they do not result from PURGE requests.
2129 Forward any HTCP CLR requests this proxy receives to the peer.
2132 ==== PEER SELECTION METHODS ====
2134 The default peer selection method is ICP, with the first responding peer
2135 being used as source. These options can be used for better load balancing.
2138 default This is a parent cache which can be used as a "last-resort"
2139 if a peer cannot be located by any of the peer-selection methods.
2140 If specified more than once, only the first is used.
2142 round-robin Load-Balance parents which should be used in a round-robin
2143 fashion in the absence of any ICP queries.
2144 weight=N can be used to add bias.
2146 weighted-round-robin
2147 Load-Balance parents which should be used in a round-robin
2148 fashion with the frequency of each parent being based on the
2149 round trip time. Closer parents are used more often.
2150 Usually used for background-ping parents.
2151 weight=N can be used to add bias.
2153 carp Load-Balance parents which should be used as a CARP array.
2154 The requests will be distributed among the parents based on the
2155 CARP load balancing hash function based on their weight.
2157 userhash Load-balance parents based on the client proxy_auth or ident username.
2159 sourcehash Load-balance parents based on the client source IP.
2162 To be used only for cache peers of type "multicast".
2163 ALL members of this multicast group have "sibling"
2164 relationship with it, not "parent". This is to a mulicast
2165 group when the requested object would be fetched only from
2166 a "parent" cache, anyway. It's useful, e.g., when
2167 configuring a pool of redundant Squid proxies, being
2168 members of the same multicast group.
2171 ==== PEER SELECTION OPTIONS ====
2173 weight=N use to affect the selection of a peer during any weighted
2174 peer-selection mechanisms.
2175 The weight must be an integer; default is 1,
2176 larger weights are favored more.
2177 This option does not affect parent selection if a peering
2178 protocol is not in use.
2180 basetime=N Specify a base amount to be subtracted from round trip
2182 It is subtracted before division by weight in calculating
2183 which parent to fectch from. If the rtt is less than the
2184 base time the rtt is set to a minimal value.
2186 ttl=N Specify a TTL to use when sending multicast ICP queries
2188 Only useful when sending to a multicast group.
2189 Because we don't accept ICP replies from random
2190 hosts, you must configure other group members as
2191 peers with the 'multicast-responder' option.
2193 no-delay To prevent access to this neighbor from influencing the
2196 digest-url=URL Tell Squid to fetch the cache digest (if digests are
2197 enabled) for this host from the specified URL rather
2198 than the Squid default location.
2201 ==== ACCELERATOR / REVERSE-PROXY OPTIONS ====
2203 originserver Causes this parent to be contacted as an origin server.
2204 Meant to be used in accelerator setups when the peer
2208 Set the Host header of requests forwarded to this peer.
2209 Useful in accelerator setups where the server (peer)
2210 expects a certain domain name but clients may request
2211 others. ie example.com or www.example.com
2213 no-digest Disable request of cache digests.
2216 Disables requesting ICMP RTT database (NetDB).
2219 ==== AUTHENTICATION OPTIONS ====
2222 If this is a personal/workgroup proxy and your parent
2223 requires proxy authentication.
2225 Note: The string can include URL escapes (i.e. %20 for
2226 spaces). This also means % must be written as %%.
2229 Send login details received from client to this peer.
2230 Both Proxy- and WWW-Authorization headers are passed
2231 without alteration to the peer.
2232 Authentication is not required by Squid for this to work.
2234 Note: This will pass any form of authentication but
2235 only Basic auth will work through a proxy unless the
2236 connection-auth options are also used.
2238 login=PASS Send login details received from client to this peer.
2239 Authentication is not required by this option.
2241 If there are no client-provided authentication headers
2242 to pass on, but username and password are available
2243 from an external ACL user= and password= result tags
2244 they may be sent instead.
2246 Note: To combine this with proxy_auth both proxies must
2247 share the same user database as HTTP only allows for
2248 a single login (one for proxy, one for origin server).
2249 Also be warned this will expose your users proxy
2250 password to the peer. USE WITH CAUTION
2253 Send the username to the upstream cache, but with a
2254 fixed password. This is meant to be used when the peer
2255 is in another administrative domain, but it is still
2256 needed to identify each user.
2257 The star can optionally be followed by some extra
2258 information which is added to the username. This can
2259 be used to identify this proxy to the peer, similar to
2260 the login=username:password option above.
2263 If this is a personal/workgroup proxy and your parent
2264 requires a secure proxy authentication.
2265 The first principal from the default keytab or defined by
2266 the environment variable KRB5_KTNAME will be used.
2268 login=NEGOTIATE:principal_name
2269 If this is a personal/workgroup proxy and your parent
2270 requires a secure proxy authentication.
2271 The principal principal_name from the default keytab or
2272 defined by the environment variable KRB5_KTNAME will be
2275 connection-auth=on|off
2276 Tell Squid that this peer does or not support Microsoft
2277 connection oriented authentication, and any such
2278 challenges received from there should be ignored.
2279 Default is auto to automatically determine the status
2283 ==== SSL / HTTPS / TLS OPTIONS ====
2285 ssl Encrypt connections to this peer with SSL/TLS.
2287 sslcert=/path/to/ssl/certificate
2288 A client SSL certificate to use when connecting to
2291 sslkey=/path/to/ssl/key
2292 The private SSL key corresponding to sslcert above.
2293 If 'sslkey' is not specified 'sslcert' is assumed to
2294 reference a combined file containing both the
2295 certificate and the key.
2298 The SSL version to use when connecting to this peer
2299 1 = automatic (default)
2304 sslcipher=... The list of valid SSL ciphers to use when connecting
2307 ssloptions=... Specify various SSL engine options:
2308 NO_SSLv2 Disallow the use of SSLv2
2309 NO_SSLv3 Disallow the use of SSLv3
2310 NO_TLSv1 Disallow the use of TLSv1
2311 See src/ssl_support.c or the OpenSSL documentation for
2312 a more complete list.
2314 sslcafile=... A file containing additional CA certificates to use
2315 when verifying the peer certificate.
2317 sslcapath=... A directory containing additional CA certificates to
2318 use when verifying the peer certificate.
2320 sslcrlfile=... A certificate revocation list file to use when
2321 verifying the peer certificate.
2323 sslflags=... Specify various flags modifying the SSL implementation:
2326 Accept certificates even if they fail to
2329 Don't use the default CA list built in
2332 Don't verify the peer certificate
2333 matches the server name
2335 ssldomain= The peer name as advertised in it's certificate.
2336 Used for verifying the correctness of the received peer
2337 certificate. If not specified the peer hostname will be
2341 Enable the "Front-End-Https: On" header needed when
2342 using Squid as a SSL frontend in front of Microsoft OWA.
2343 See MS KB document Q307347 for details on this header.
2344 If set to auto the header will only be added if the
2345 request is forwarded as a https:// URL.
2348 ==== GENERAL OPTIONS ====
2351 A peer-specific connect timeout.
2352 Also see the peer_connect_timeout directive.
2354 connect-fail-limit=N
2355 How many times connecting to a peer must fail before
2356 it is marked as down. Default is 10.
2358 allow-miss Disable Squid's use of only-if-cached when forwarding
2359 requests to siblings. This is primarily useful when
2360 icp_hit_stale is used by the sibling. To extensive use
2361 of this option may result in forwarding loops, and you
2362 should avoid having two-way peerings with this option.
2363 For example to deny peer usage on requests from peer
2364 by denying cache_peer_access if the source is a peer.
2366 max-conn=N Limit the amount of connections Squid may open to this
2369 name=xxx Unique name for the peer.
2370 Required if you have multiple peers on the same host
2371 but different ports.
2372 This name can be used in cache_peer_access and similar
2373 directives to dentify the peer.
2374 Can be used by outgoing access controls through the
2377 no-tproxy Do not use the client-spoof TPROXY support when forwarding
2378 requests to this peer. Use normal address selection instead.
2380 proxy-only objects fetched from the peer will not be stored locally.
2384 NAME: cache_peer_domain cache_host_domain
2389 Use to limit the domains for which a neighbor cache will be
2392 cache_peer_domain cache-host domain [domain ...]
2393 cache_peer_domain cache-host !domain
2395 For example, specifying
2397 cache_peer_domain parent.foo.net .edu
2399 has the effect such that UDP query packets are sent to
2400 'bigserver' only when the requested object exists on a
2401 server in the .edu domain. Prefixing the domainname
2402 with '!' means the cache will be queried for objects
2405 NOTE: * Any number of domains may be given for a cache-host,
2406 either on the same or separate lines.
2407 * When multiple domains are given for a particular
2408 cache-host, the first matched domain is applied.
2409 * Cache hosts with no domain restrictions are queried
2411 * There are no defaults.
2412 * There is also a 'cache_peer_access' tag in the ACL
2416 NAME: cache_peer_access
2421 Similar to 'cache_peer_domain' but provides more flexibility by
2424 cache_peer_access cache-host allow|deny [!]aclname ...
2426 The syntax is identical to 'http_access' and the other lists of
2427 ACL elements. See the comments for 'http_access' below, or
2428 the Squid FAQ (http://wiki.squid-cache.org/SquidFaq/SquidAcl).
2431 NAME: neighbor_type_domain
2432 TYPE: hostdomaintype
2436 usage: neighbor_type_domain neighbor parent|sibling domain domain ...
2438 Modifying the neighbor type for specific domains is now
2439 possible. You can treat some domains differently than the
2440 default neighbor type specified on the 'cache_peer' line.
2441 Normally it should only be necessary to list domains which
2442 should be treated differently because the default neighbor type
2443 applies for hostnames which do not match domains listed here.
2446 cache_peer cache.foo.org parent 3128 3130
2447 neighbor_type_domain cache.foo.org sibling .com .net
2448 neighbor_type_domain cache.foo.org sibling .au .de
2451 NAME: dead_peer_timeout
2455 LOC: Config.Timeout.deadPeer
2457 This controls how long Squid waits to declare a peer cache
2458 as "dead." If there are no ICP replies received in this
2459 amount of time, Squid will declare the peer dead and not
2460 expect to receive any further ICP replies. However, it
2461 continues to send ICP queries, and will mark the peer as
2462 alive upon receipt of the first subsequent ICP reply.
2464 This timeout also affects when Squid expects to receive ICP
2465 replies from peers. If more than 'dead_peer' seconds have
2466 passed since the last ICP reply was received, Squid will not
2467 expect to receive an ICP reply on the next query. Thus, if
2468 your time between requests is greater than this timeout, you
2469 will see a lot of requests sent DIRECT to origin servers
2470 instead of to your parents.
2473 NAME: forward_max_tries
2476 LOC: Config.forward_max_tries
2478 Controls how many different forward paths Squid will try
2479 before giving up. See also forward_timeout.
2482 NAME: hierarchy_stoplist
2485 LOC: Config.hierarchy_stoplist
2487 A list of words which, if found in a URL, cause the object to
2488 be handled directly by this cache. In other words, use this
2489 to not query neighbor caches for certain objects. You may
2490 list this option multiple times.
2491 Note: never_direct overrides this option.
2494 # We recommend you to use at least the following line.
2495 hierarchy_stoplist cgi-bin ?
2500 MEMORY CACHE OPTIONS
2501 -----------------------------------------------------------------------------
2508 LOC: Config.memMaxSize
2510 NOTE: THIS PARAMETER DOES NOT SPECIFY THE MAXIMUM PROCESS SIZE.
2511 IT ONLY PLACES A LIMIT ON HOW MUCH ADDITIONAL MEMORY SQUID WILL
2512 USE AS A MEMORY CACHE OF OBJECTS. SQUID USES MEMORY FOR OTHER
2513 THINGS AS WELL. SEE THE SQUID FAQ SECTION 8 FOR DETAILS.
2515 'cache_mem' specifies the ideal amount of memory to be used
2517 * In-Transit objects
2519 * Negative-Cached objects
2521 Data for these objects are stored in 4 KB blocks. This
2522 parameter specifies the ideal upper limit on the total size of
2523 4 KB blocks allocated. In-Transit objects take the highest
2526 In-transit objects have priority over the others. When
2527 additional space is needed for incoming data, negative-cached
2528 and hot objects will be released. In other words, the
2529 negative-cached and hot objects will fill up any unused space
2530 not needed for in-transit objects.
2532 If circumstances require, this limit will be exceeded.
2533 Specifically, if your incoming request rate requires more than
2534 'cache_mem' of memory to hold in-transit objects, Squid will
2535 exceed this limit to satisfy the new requests. When the load
2536 decreases, blocks will be freed until the high-water mark is
2537 reached. Thereafter, blocks will be used to store hot
2541 NAME: maximum_object_size_in_memory
2545 LOC: Config.Store.maxInMemObjSize
2547 Objects greater than this size will not be attempted to kept in
2548 the memory cache. This should be set high enough to keep objects
2549 accessed frequently in memory to improve performance whilst low
2550 enough to keep larger objects from hoarding cache_mem.
2553 NAME: memory_cache_mode
2558 Controls which objects to keep in the memory cache (cache_mem)
2560 always Keep most recently fetched objects in memory (default)
2562 disk Only disk cache hits are kept in memory, which means
2563 an object must first be cached on disk and then hit
2564 a second time before cached in memory.
2566 network Only objects fetched from network is kept in memory
2569 NAME: memory_replacement_policy
2571 LOC: Config.memPolicy
2574 The memory replacement policy parameter determines which
2575 objects are purged from memory when memory space is needed.
2577 See cache_replacement_policy for details.
2582 -----------------------------------------------------------------------------
2585 NAME: cache_replacement_policy
2587 LOC: Config.replPolicy
2590 The cache replacement policy parameter determines which
2591 objects are evicted (replaced) when disk space is needed.
2593 lru : Squid's original list based LRU policy
2594 heap GDSF : Greedy-Dual Size Frequency
2595 heap LFUDA: Least Frequently Used with Dynamic Aging
2596 heap LRU : LRU policy implemented using a heap
2598 Applies to any cache_dir lines listed below this.
2600 The LRU policies keeps recently referenced objects.
2602 The heap GDSF policy optimizes object hit rate by keeping smaller
2603 popular objects in cache so it has a better chance of getting a
2604 hit. It achieves a lower byte hit rate than LFUDA though since
2605 it evicts larger (possibly popular) objects.
2607 The heap LFUDA policy keeps popular objects in cache regardless of
2608 their size and thus optimizes byte hit rate at the expense of
2609 hit rate since one large, popular object will prevent many
2610 smaller, slightly less popular objects from being cached.
2612 Both policies utilize a dynamic aging mechanism that prevents
2613 cache pollution that can otherwise occur with frequency-based
2614 replacement policies.
2616 NOTE: if using the LFUDA replacement policy you should increase
2617 the value of maximum_object_size above its default of 4096 KB to
2618 to maximize the potential byte hit rate improvement of LFUDA.
2620 For more information about the GDSF and LFUDA cache replacement
2621 policies see http://www.hpl.hp.com/techreports/1999/HPL-1999-69.html
2622 and http://fog.hpl.external.hp.com/techreports/98/HPL-98-173.html.
2628 LOC: Config.cacheSwap
2632 cache_dir Type Directory-Name Fs-specific-data [options]
2634 You can specify multiple cache_dir lines to spread the
2635 cache among different disk partitions.
2637 Type specifies the kind of storage system to use. Only "ufs"
2638 is built by default. To enable any of the other storage systems
2639 see the --enable-storeio configure option.
2641 'Directory' is a top-level directory where cache swap
2642 files will be stored. If you want to use an entire disk
2643 for caching, this can be the mount-point directory.
2644 The directory must exist and be writable by the Squid
2645 process. Squid will NOT create this directory for you.
2647 In SMP configurations, cache_dir must not precede the workers option
2648 and should use configuration macros or conditionals to give each
2649 worker interested in disk caching a dedicated cache directory.
2653 "ufs" is the old well-known Squid storage format that has always
2656 cache_dir ufs Directory-Name Mbytes L1 L2 [options]
2658 'Mbytes' is the amount of disk space (MB) to use under this
2659 directory. The default is 100 MB. Change this to suit your
2660 configuration. Do NOT put the size of your disk drive here.
2661 Instead, if you want Squid to use the entire disk drive,
2662 subtract 20% and use that value.
2664 'L1' is the number of first-level subdirectories which
2665 will be created under the 'Directory'. The default is 16.
2667 'L2' is the number of second-level subdirectories which
2668 will be created under each first-level directory. The default
2671 The aufs store type:
2673 "aufs" uses the same storage format as "ufs", utilizing
2674 POSIX-threads to avoid blocking the main Squid process on
2675 disk-I/O. This was formerly known in Squid as async-io.
2677 cache_dir aufs Directory-Name Mbytes L1 L2 [options]
2679 see argument descriptions under ufs above
2681 The diskd store type:
2683 "diskd" uses the same storage format as "ufs", utilizing a
2684 separate process to avoid blocking the main Squid process on
2687 cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n]
2689 see argument descriptions under ufs above
2691 Q1 specifies the number of unacknowledged I/O requests when Squid
2692 stops opening new files. If this many messages are in the queues,
2693 Squid won't open new files. Default is 64
2695 Q2 specifies the number of unacknowledged messages when Squid
2696 starts blocking. If this many messages are in the queues,
2697 Squid blocks until it receives some replies. Default is 72
2699 When Q1 < Q2 (the default), the cache directory is optimized
2700 for lower response time at the expense of a decrease in hit
2701 ratio. If Q1 > Q2, the cache directory is optimized for
2702 higher hit ratio at the expense of an increase in response
2705 The coss store type:
2707 NP: COSS filesystem in Squid-3 has been deemed too unstable for
2708 production use and has thus been removed from this release.
2709 We hope that it can be made usable again soon.
2711 block-size=n defines the "block size" for COSS cache_dir's.
2712 Squid uses file numbers as block numbers. Since file numbers
2713 are limited to 24 bits, the block size determines the maximum
2714 size of the COSS partition. The default is 512 bytes, which
2715 leads to a maximum cache_dir size of 512<<24, or 8 GB. Note
2716 you should not change the coss block size after Squid
2717 has written some objects to the cache_dir.
2719 The coss file store has changed from 2.5. Now it uses a file
2720 called 'stripe' in the directory names in the config - and
2721 this will be created by squid -z.
2725 no-store, no new objects should be stored to this cache_dir
2727 min-size=n, refers to the min object size in bytes this cache_dir
2728 will accept. It's used to restrict a cache_dir to only store
2729 large objects (e.g. aufs) while other storedirs are optimized
2730 for smaller objects (e.g. COSS). Defaults to 0.
2732 max-size=n, refers to the max object size in bytes this cache_dir
2733 supports. It is used to select the cache_dir to store the object.
2734 Note: To make optimal use of the max-size limits you should order
2735 the cache_dir lines with the smallest max-size value first and the
2736 ones with no max-size specification last.
2738 Note for coss, max-size must be less than COSS_MEMBUF_SZ,
2739 which can be changed with the --with-coss-membuf-size=N configure
2743 # Uncomment and adjust the following to add a disk cache directory.
2744 #cache_dir ufs @DEFAULT_SWAP_DIR@ 100 16 256
2748 NAME: store_dir_select_algorithm
2750 LOC: Config.store_dir_select_algorithm
2753 Set this to 'round-robin' as an alternative.
2756 NAME: max_open_disk_fds
2758 LOC: Config.max_open_disk_fds
2761 To avoid having disk as the I/O bottleneck Squid can optionally
2762 bypass the on-disk cache if more than this amount of disk file
2763 descriptors are open.
2765 A value of 0 indicates no limit.
2768 NAME: minimum_object_size
2772 LOC: Config.Store.minObjectSize
2774 Objects smaller than this size will NOT be saved on disk. The
2775 value is specified in kilobytes, and the default is 0 KB, which
2776 means there is no minimum.
2779 NAME: maximum_object_size
2783 LOC: Config.Store.maxObjectSize
2785 Objects larger than this size will NOT be saved on disk. The
2786 value is specified in kilobytes, and the default is 4MB. If
2787 you wish to get a high BYTES hit ratio, you should probably
2788 increase this (one 32 MB object hit counts for 3200 10KB
2789 hits). If you wish to increase speed more than your want to
2790 save bandwidth you should leave this low.
2792 NOTE: if using the LFUDA replacement policy you should increase
2793 this value to maximize the byte hit rate improvement of LFUDA!
2794 See replacement_policy below for a discussion of this policy.
2797 NAME: cache_swap_low
2798 COMMENT: (percent, 0-100)
2801 LOC: Config.Swap.lowWaterMark
2804 NAME: cache_swap_high
2805 COMMENT: (percent, 0-100)
2808 LOC: Config.Swap.highWaterMark
2811 The low- and high-water marks for cache object replacement.
2812 Replacement begins when the swap (disk) usage is above the
2813 low-water mark and attempts to maintain utilization near the
2814 low-water mark. As swap utilization gets close to high-water
2815 mark object eviction becomes more aggressive. If utilization is
2816 close to the low-water mark less replacement is done each time.
2818 Defaults are 90% and 95%. If you have a large cache, 5% could be
2819 hundreds of MB. If this is the case you may wish to set these
2820 numbers closer together.
2825 -----------------------------------------------------------------------------
2835 logformat <name> <format specification>
2837 Defines an access log format.
2839 The <format specification> is a string with embedded % format codes
2841 % format codes all follow the same basic structure where all but
2842 the formatcode is optional. Output strings are automatically escaped
2843 as required according to their context and the output format
2844 modifiers are usually not needed, but can be specified if an explicit
2845 output format is desired.
2847 % ["|[|'|#] [-] [[0]width] [{argument}] formatcode
2849 " output in quoted string format
2850 [ output in squid text log format as used by log_mime_hdrs
2851 # output in URL quoted format
2855 width field width. If starting with 0 the
2856 output is zero padded
2857 {arg} argument such as header name etc
2861 % a literal % character
2862 sn Unique sequence number per log line entry
2863 err_code The ID of an error response served by Squid or
2864 a similar internal error identifier.
2865 err_detail Additional err_code-dependent error information.
2867 Connection related format codes:
2869 >a Client source IP address
2871 >p Client source port
2872 >eui Client EUI (MAC address, EUI-48 or EUI-64 identifier)
2873 <A Server IP address or peer name
2874 la Local IP address (http_port)
2875 lp Local port number (http_port)
2876 <la Local IP address of the last server or peer connection
2877 <lp Local port number of the last server or peer connection
2879 Time related format codes:
2881 ts Seconds since epoch
2882 tu subsecond time (milliseconds)
2883 tl Local time. Optional strftime format argument
2884 default %d/%b/%Y:%H:%M:%S %z
2885 tg GMT time. Optional strftime format argument
2886 default %d/%b/%Y:%H:%M:%S %z
2887 tr Response time (milliseconds)
2888 dt Total time spent making DNS lookups (milliseconds)
2890 HTTP cache related format codes:
2892 [http::]>h Original request header. Optional header name argument
2893 on the format header[:[separator]element]
2894 [http::]>ha The HTTP request headers after adaptation and redirection.
2895 Optional header name argument as for >h
2896 [http::]<h Reply header. Optional header name argument
2898 [http::]un User name
2899 [http::]ul User name from authentication
2900 [http::]ui User name from ident
2901 [http::]us User name from SSL
2902 [http::]ue User name from external acl helper
2903 [http::]>Hs HTTP status code sent to the client
2904 [http::]<Hs HTTP status code received from the next hop
2905 [http::]<bs Number of HTTP-equivalent message body bytes
2906 received from the next hop, excluding chunked
2907 transfer encoding and control messages.
2908 Generated FTP/Gopher listings are treated as
2910 [http::]Ss Squid request status (TCP_MISS etc)
2911 [http::]Sh Squid hierarchy status (DEFAULT_PARENT etc)
2912 [http::]mt MIME content type
2913 [http::]rm Request method (GET/POST etc)
2914 [http::]ru Request URL
2915 [http::]rp Request URL-Path excluding hostname
2916 [http::]rv Request protocol version
2917 [http::]et Tag returned by external acl
2918 [http::]ea Log string returned by external acl
2919 [http::]<st Sent reply size including HTTP headers
2920 [http::]>st Received request size including HTTP headers. In the
2921 case of chunked requests the chunked encoding metadata
2923 [http::]>sh Received HTTP request headers size
2924 [http::]<sh Sent HTTP reply headers size
2925 [http::]st Request+Reply size including HTTP headers
2926 [http::]<sH Reply high offset sent
2927 [http::]<sS Upstream object size
2928 [http::]<pt Peer response time in milliseconds. The timer starts
2929 when the last request byte is sent to the next hop
2930 and stops when the last response byte is received.
2931 [http::]<tt Total server-side time in milliseconds. The timer
2932 starts with the first connect request (or write I/O)
2933 sent to the first selected peer. The timer stops
2934 with the last I/O with the last peer.
2936 If ICAP is enabled, the following code becomes available (as
2937 well as ICAP log codes documented with the icap_log option):
2939 icap::tt Total ICAP processing time for the HTTP
2940 transaction. The timer ticks when ICAP
2941 ACLs are checked and when ICAP
2942 transaction is in progress.
2944 If adaptation is enabled the following three codes become available:
2946 adapt::<last_h The header of the last ICAP response or
2947 meta-information from the last eCAP
2948 transaction related to the HTTP transaction.
2949 Like <h, accepts an optional header name
2952 adapt::sum_trs Summed adaptation transaction response
2953 times recorded as a comma-separated list in
2954 the order of transaction start time. Each time
2955 value is recorded as an integer number,
2956 representing response time of one or more
2957 adaptation (ICAP or eCAP) transaction in
2958 milliseconds. When a failed transaction is
2959 being retried or repeated, its time is not
2960 logged individually but added to the
2961 replacement (next) transaction. See also:
2964 adapt::all_trs All adaptation transaction response times.
2965 Same as adaptation_strs but response times of
2966 individual transactions are never added
2967 together. Instead, all transaction response
2968 times are recorded individually.
2970 You can prefix adapt::*_trs format codes with adaptation
2971 service name in curly braces to record response time(s) specific
2972 to that service. For example: %{my_service}adapt::sum_trs
2974 The default formats available (which do not need re-defining) are:
2976 logformat squid %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %un %Sh/%<A %mt
2977 logformat common %>a %ui %un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st %Ss:%Sh
2978 logformat combined %>a %ui %un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
2979 logformat referrer %ts.%03tu %>a %{Referer}>h %ru
2980 logformat useragent %>a [%tl] "%{User-Agent}>h"
2982 When the log_mime_hdrs directive is set to ON. The squid, common and combined
2983 formats have a safely encoded copy of the mime headers appended to each line
2984 within a pair of brackets.
2986 The common and combined formats are not quite true to the Apache definition.
2987 The logs from Squid contain an extra status and hierarchy code appended.
2990 NAME: access_log cache_access_log
2992 LOC: Config.Log.accesslogs
2993 DEFAULT_IF_NONE: daemon:@DEFAULT_ACCESS_LOG@ squid
2995 These files log client request activities. Has a line every HTTP or
2996 ICP request. The format is:
2997 access_log <module>:<place> [<logformat name> [acl acl ...]]
2998 access_log none [acl acl ...]]
3000 Will log to the specified module:place using the specified format (which
3001 must be defined in a logformat directive) those entries which match
3002 ALL the acl's specified (which must be defined in acl clauses).
3003 If no acl is specified, all requests will be logged to this destination.
3005 ===== Modules Currently available =====
3007 none Do not log any requests matching these ACL.
3008 Do not specify Place or logformat name.
3010 stdio Write each log line to disk immediately at the completion of
3012 Place: the filename and path to be written.
3014 daemon Very similar to stdio. But instead of writing to disk the log
3015 line is passed to a daemon helper for asychronous handling instead.
3016 Place: varies depending on the daemon.
3018 log_file_daemon Place: the file name and path to be written.
3020 syslog To log each request via syslog facility.
3021 Place: The syslog facility and priority level for these entries.
3022 Place Format: facility.priority
3024 where facility could be any of:
3025 authpriv, daemon, local0 ... local7 or user.
3027 And priority could be any of:
3028 err, warning, notice, info, debug.
3030 udp To send each log line as text data to a UDP receiver.
3031 Place: The destination host name or IP and port.
3032 Place Format: \\host:port
3034 tcp To send each log line as text data to a TCP receiver.
3035 Place: The destination host name or IP and port.
3036 Place Format: \\host:port
3039 access_log daemon:@DEFAULT_ACCESS_LOG@ squid
3045 LOC: Config.Log.icaplogs
3048 ICAP log files record ICAP transaction summaries, one line per
3051 The icap_log option format is:
3052 icap_log <filepath> [<logformat name> [acl acl ...]]
3053 icap_log none [acl acl ...]]
3055 Please see access_log option documentation for details. The two
3056 kinds of logs share the overall configuration approach and many
3059 ICAP processing of a single HTTP message or transaction may
3060 require multiple ICAP transactions. In such cases, multiple
3061 ICAP transaction log lines will correspond to a single access
3064 ICAP log uses logformat codes that make sense for an ICAP
3065 transaction. Header-related codes are applied to the HTTP header
3066 embedded in an ICAP server response, with the following caveats:
3067 For REQMOD, there is no HTTP response header unless the ICAP
3068 server performed request satisfaction. For RESPMOD, the HTTP
3069 request header is the header sent to the ICAP server. For
3070 OPTIONS, there are no HTTP headers.
3072 The following format codes are also available for ICAP logs:
3074 icap::<A ICAP server IP address. Similar to <A.
3076 icap::<service_name ICAP service name from the icap_service
3077 option in Squid configuration file.
3079 icap::ru ICAP Request-URI. Similar to ru.
3081 icap::rm ICAP request method (REQMOD, RESPMOD, or
3082 OPTIONS). Similar to existing rm.
3084 icap::>st Bytes sent to the ICAP server (TCP payload
3085 only; i.e., what Squid writes to the socket).
3087 icap::<st Bytes received from the ICAP server (TCP
3088 payload only; i.e., what Squid reads from
3091 icap::<bs Number of message body bytes received from the
3092 ICAP server. ICAP message body, if any, usually
3093 includes encapsulated HTTP message headers and
3094 possibly encapsulated HTTP message body. The
3095 HTTP body part is dechunked before its size is
3098 icap::tr Transaction response time (in
3099 milliseconds). The timer starts when
3100 the ICAP transaction is created and
3101 stops when the transaction is completed.
3104 icap::tio Transaction I/O time (in milliseconds). The
3105 timer starts when the first ICAP request
3106 byte is scheduled for sending. The timers
3107 stops when the last byte of the ICAP response
3110 icap::to Transaction outcome: ICAP_ERR* for all
3111 transaction errors, ICAP_OPT for OPTION
3112 transactions, ICAP_ECHO for 204
3113 responses, ICAP_MOD for message
3114 modification, and ICAP_SAT for request
3115 satisfaction. Similar to Ss.
3117 icap::Hs ICAP response status code. Similar to Hs.
3119 icap::>h ICAP request header(s). Similar to >h.
3121 icap::<h ICAP response header(s). Similar to <h.
3123 The default ICAP log format, which can be used without an explicit
3124 definition, is called icap_squid:
3126 logformat icap_squid %ts.%03tu %6icap::tr %>a %icap::to/%03icap::Hs %icap::<size %icap::rm %icap::ru% %un -/%icap::<A -
3128 See also: logformat, log_icap, and %adapt::<last_h
3131 NAME: logfile_daemon
3133 DEFAULT: @DEFAULT_LOGFILED@
3134 LOC: Log::TheConfig.logfile_daemon
3136 Specify the path to the logfile-writing daemon. This daemon is
3137 used to write the access and store logs, if configured.
3139 Squid sends a number of commands to the log daemon:
3140 L<data>\n - logfile data
3145 r<n>\n - set rotate count to <n>
3146 b<n>\n - 1 = buffer output, 0 = don't buffer output
3148 No responses is expected.
3153 LOC: Config.accessList.log
3155 COMMENT: allow|deny acl acl...
3157 This options allows you to control which requests gets logged
3158 to access.log (see access_log directive). Requests denied for
3159 logging will also not be accounted for in performance counters.
3161 This clause only supports fast acl types.
3162 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
3168 LOC: Config.accessList.icap
3171 This options allows you to control which requests get logged
3172 to icap.log. See the icap_log directive for ICAP log details.
3175 NAME: cache_store_log
3178 LOC: Config.Log.store
3180 Logs the activities of the storage manager. Shows which
3181 objects are ejected from the cache, and which objects are
3182 saved and for how long. To disable, enter "none" or remove the line.
3183 There are not really utilities to analyze this data, so you can safely
3187 cache_store_log @DEFAULT_STORE_LOG@
3190 NAME: cache_swap_state cache_swap_log
3192 LOC: Config.Log.swap
3195 Location for the cache "swap.state" file. This index file holds
3196 the metadata of objects saved on disk. It is used to rebuild
3197 the cache during startup. Normally this file resides in each
3198 'cache_dir' directory, but you may specify an alternate
3199 pathname here. Note you must give a full filename, not just
3200 a directory. Since this is the index for the whole object
3201 list you CANNOT periodically rotate it!
3203 If %s can be used in the file name it will be replaced with a
3204 a representation of the cache_dir name where each / is replaced
3205 with '.'. This is needed to allow adding/removing cache_dir
3206 lines when cache_swap_log is being used.
3208 If have more than one 'cache_dir', and %s is not used in the name
3209 these swap logs will have names such as:
3215 The numbered extension (which is added automatically)
3216 corresponds to the order of the 'cache_dir' lines in this
3217 configuration file. If you change the order of the 'cache_dir'
3218 lines in this file, these index files will NOT correspond to
3219 the correct 'cache_dir' entry (unless you manually rename
3220 them). We recommend you do NOT use this option. It is
3221 better to keep these index files in each 'cache_dir' directory.
3224 NAME: logfile_rotate
3227 LOC: Config.Log.rotateNumber
3229 Specifies the number of logfile rotations to make when you
3230 type 'squid -k rotate'. The default is 10, which will rotate
3231 with extensions 0 through 9. Setting logfile_rotate to 0 will
3232 disable the file name rotation, but the logfiles are still closed
3233 and re-opened. This will enable you to rename the logfiles
3234 yourself just before sending the rotate signal.
3236 Note, the 'squid -k rotate' command normally sends a USR1
3237 signal to the running squid process. In certain situations
3238 (e.g. on Linux with Async I/O), USR1 is used for other
3239 purposes, so -k rotate uses another signal. It is best to get
3240 in the habit of using 'squid -k rotate' instead of 'kill -USR1
3243 Note, from Squid-3.1 this option has no effect on the cache.log,
3244 that log can be rotated separately by using debug_options
3247 NAME: emulate_httpd_log
3250 Replace this with an access_log directive using the format 'common' or 'combined'.
3253 NAME: log_ip_on_direct
3257 LOC: Config.onoff.log_ip_on_direct
3259 Log the destination IP address in the hierarchy log tag when going
3260 direct. Earlier Squid versions logged the hostname here. If you
3261 prefer the old way set this to off.
3266 DEFAULT: @DEFAULT_MIME_TABLE@
3267 LOC: Config.mimeTablePathname
3269 Pathname to Squid's MIME table. You shouldn't need to change
3270 this, but the default file contains examples and formatting
3271 information if you do.
3277 LOC: Config.onoff.log_mime_hdrs
3280 The Cache can record both the request and the response MIME
3281 headers for each HTTP transaction. The headers are encoded
3282 safely and will appear as two bracketed fields at the end of
3283 the access log (for either the native or httpd-emulated log
3284 formats). To enable this logging set log_mime_hdrs to 'on'.
3290 Replace this with an access_log directive using the format 'useragent'.
3293 NAME: referer_log referrer_log
3296 Replace this with an access_log directive using the format 'referrer'.
3301 DEFAULT: @DEFAULT_PID_FILE@
3302 LOC: Config.pidFilename
3304 A filename to write the process-id to. To disable, enter "none".
3310 Remove this option from your config. To log FQDN use %>A in the log format.
3313 NAME: client_netmask
3315 LOC: Config.Addrs.client_netmask
3318 A netmask for client addresses in logfiles and cachemgr output.
3319 Change this to protect the privacy of your cache clients.
3320 A netmask of 255.255.255.0 will log all IP's in that range with
3321 the last digit set to '0'.
3327 Use a regular access.log with ACL limiting it to MISS events.
3330 NAME: strip_query_terms
3332 LOC: Config.onoff.strip_query_terms
3335 By default, Squid strips query terms from requested URLs before
3336 logging. This protects your user's privacy.
3343 LOC: Config.onoff.buffered_logs
3345 cache.log log file is written with stdio functions, and as such
3346 it can be buffered or unbuffered. By default it will be unbuffered.
3347 Buffering it can speed up the writing slightly (though you are
3348 unlikely to need to worry unless you run with tons of debugging
3349 enabled in which case performance will suffer badly anyway..).
3352 NAME: netdb_filename
3354 DEFAULT: @DEFAULT_NETDB_FILE@
3355 LOC: Config.netdbFilename
3358 A filename where Squid stores it's netdb state between restarts.
3359 To disable, enter "none".
3363 OPTIONS FOR TROUBLESHOOTING
3364 -----------------------------------------------------------------------------
3369 DEFAULT_IF_NONE: @DEFAULT_CACHE_LOG@
3370 LOC: Debug::cache_log
3372 Cache logging file. This is where general information about
3373 your cache's behavior goes. You can increase the amount of data
3374 logged to this file and how often its rotated with "debug_options"
3380 LOC: Debug::debugOptions
3382 Logging options are set as section,level where each source file
3383 is assigned a unique section. Lower levels result in less
3384 output, Full debugging (level 9) can result in a very large
3385 log file, so be careful.
3387 The magic word "ALL" sets debugging levels for all sections.
3388 We recommend normally running with "ALL,1".
3390 The rotate=N option can be used to keep more or less of these logs
3391 than would otherwise be kept by logfile_rotate.
3392 For most uses a single log should be enough to monitor current
3393 events affecting Squid.
3398 LOC: Config.coredump_dir
3399 DEFAULT_IF_NONE: none
3401 By default Squid leaves core files in the directory from where
3402 it was started. If you set 'coredump_dir' to a directory
3403 that exists, Squid will chdir() to that directory at startup
3404 and coredump files will be left there.
3408 # Leave coredumps in the first cache dir
3409 coredump_dir @DEFAULT_SWAP_DIR@
3415 OPTIONS FOR FTP GATEWAYING
3416 -----------------------------------------------------------------------------
3422 LOC: Config.Ftp.anon_user
3424 If you want the anonymous login password to be more informative
3425 (and enable the use of picky ftp servers), set this to something
3426 reasonable for your domain, like wwwuser@somewhere.net
3428 The reason why this is domainless by default is the
3429 request can be made on the behalf of a user in any domain,
3430 depending on how the cache is used.
3431 Some ftp server also validate the email address is valid
3432 (for example perl.com).
3438 LOC: Config.Ftp.passive
3440 If your firewall does not allow Squid to use passive
3441 connections, turn off this option.
3443 Use of ftp_epsv_all option requires this to be ON.
3449 LOC: Config.Ftp.epsv_all
3451 FTP Protocol extensions permit the use of a special "EPSV ALL" command.
3453 NATs may be able to put the connection on a "fast path" through the
3454 translator, as the EPRT command will never be used and therefore,
3455 translation of the data portion of the segments will never be needed.
3457 When a client only expects to do two-way FTP transfers this may be
3459 If squid finds that it must do a three-way FTP transfer after issuing
3460 an EPSV ALL command, the FTP session will fail.
3462 If you have any doubts about this option do not use it.
3463 Squid will nicely attempt all other connection methods.
3465 Requires ftp_passive to be ON (default) for any effect.
3471 LOC: Config.Ftp.epsv
3473 FTP Protocol extensions permit the use of a special "EPSV" command.
3475 NATs may be able to put the connection on a "fast path" through the
3476 translator using EPSV, as the EPRT command will never be used
3477 and therefore, translation of the data portion of the segments
3478 will never be needed.
3480 Turning this OFF will prevent EPSV being attempted.
3481 WARNING: Doing so will convert Squid back to the old behavior with all
3482 the related problems with external NAT devices/layers.
3484 Requires ftp_passive to be ON (default) for any effect.
3490 LOC: Config.Ftp.eprt
3492 FTP Protocol extensions permit the use of a special "EPRT" command.
3494 This extension provides a protocol neutral alternative to the
3495 IPv4-only PORT command. When supported it enables active FTP data
3496 channels over IPv6 and efficient NAT handling.
3498 Turning this OFF will prevent EPRT being attempted and will skip
3499 straight to using PORT for IPv4 servers.
3501 Some devices are known to not handle this extension correctly and
3502 may result in crashes. Devices which suport EPRT enough to fail
3503 cleanly will result in Squid attempting PORT anyway. This directive
3504 should only be disabled when EPRT results in device failures.
3506 WARNING: Doing so will convert Squid back to the old behavior with all
3507 the related problems with external NAT devices/layers and IPv4-only FTP.
3510 NAME: ftp_sanitycheck
3513 LOC: Config.Ftp.sanitycheck
3515 For security and data integrity reasons Squid by default performs
3516 sanity checks of the addresses of FTP data connections ensure the
3517 data connection is to the requested server. If you need to allow
3518 FTP connections to servers using another IP address for the data
3519 connection turn this off.
3522 NAME: ftp_telnet_protocol
3525 LOC: Config.Ftp.telnet
3527 The FTP protocol is officially defined to use the telnet protocol
3528 as transport channel for the control connection. However, many
3529 implementations are broken and does not respect this aspect of
3532 If you have trouble accessing files with ASCII code 255 in the
3533 path or similar problems involving this ASCII code you can
3534 try setting this directive to off. If that helps, report to the
3535 operator of the FTP server in question that their FTP server
3536 is broken and does not follow the FTP standard.
3540 OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
3541 -----------------------------------------------------------------------------
3546 DEFAULT: @DEFAULT_DISKD@
3547 LOC: Config.Program.diskd
3549 Specify the location of the diskd executable.
3550 Note this is only useful if you have compiled in
3551 diskd as one of the store io modules.
3554 NAME: unlinkd_program
3557 DEFAULT: @DEFAULT_UNLINKD@
3558 LOC: Config.Program.unlinkd
3560 Specify the location of the executable for file deletion process.
3563 NAME: pinger_program
3565 DEFAULT: @DEFAULT_PINGER@
3566 LOC: Config.pinger.program
3569 Specify the location of the executable for the pinger process.
3575 LOC: Config.pinger.enable
3578 Control whether the pinger is active at run-time.
3579 Enables turning ICMP pinger on and off with a simple
3580 squid -k reconfigure.
3585 OPTIONS FOR URL REWRITING
3586 -----------------------------------------------------------------------------
3589 NAME: url_rewrite_program redirect_program
3591 LOC: Config.Program.redirect
3594 Specify the location of the executable URL rewriter to use.
3595 Since they can perform almost any function there isn't one included.
3597 For each requested URL, the rewriter will receive on line with the format
3599 URL <SP> client_ip "/" fqdn <SP> user <SP> method [<SP> kvpairs]<NL>
3601 In the future, the rewriter interface will be extended with
3602 key=value pairs ("kvpairs" shown above). Rewriter programs
3603 should be prepared to receive and possibly ignore additional
3604 whitespace-separated tokens on each input line.
3606 And the rewriter may return a rewritten URL. The other components of
3607 the request line does not need to be returned (ignored if they are).
3609 The rewriter can also indicate that a client-side redirect should
3610 be performed to the new URL. This is done by prefixing the returned
3611 URL with "301:" (moved permanently) or 302: (moved temporarily), etc.
3613 By default, a URL rewriter is not used.
3616 NAME: url_rewrite_children redirect_children
3617 TYPE: HelperChildConfig
3618 DEFAULT: 20 startup=0 idle=1 concurrency=0
3619 LOC: Config.redirectChildren
3621 The maximum number of redirector processes to spawn. If you limit
3622 it too few Squid will have to wait for them to process a backlog of
3623 URLs, slowing it down. If you allow too many they will use RAM
3624 and other system resources noticably.
3626 The startup= and idle= options allow some measure of skew in your
3631 Sets a minimum of how many processes are to be spawned when Squid
3632 starts or reconfigures. When set to zero the first request will
3633 cause spawning of the first child process to handle it.
3635 Starting too few will cause an initial slowdown in traffic as Squid
3636 attempts to simultaneously spawn enough processes to cope.
3640 Sets a minimum of how many processes Squid is to try and keep available
3641 at all times. When traffic begins to rise above what the existing
3642 processes can handle this many more will be spawned up to the maximum
3643 configured. A minimum setting of 1 is required.
3647 The number of requests each redirector helper can handle in
3648 parallel. Defaults to 0 which indicates the redirector
3649 is a old-style single threaded redirector.
3651 When this directive is set to a value >= 1 then the protocol
3652 used to communicate with the helper is modified to include
3653 a request ID in front of the request/response. The request
3654 ID from the request must be echoed back with the response
3658 NAME: url_rewrite_host_header redirect_rewrites_host_header
3661 LOC: Config.onoff.redir_rewrites_host
3663 By default Squid rewrites any Host: header in redirected
3664 requests. If you are running an accelerator this may
3665 not be a wanted effect of a redirector.
3667 WARNING: Entries are cached on the result of the URL rewriting
3668 process, so be careful if you have domain-virtual hosts.
3671 NAME: url_rewrite_access redirector_access
3674 LOC: Config.accessList.redirector
3676 If defined, this access list specifies which requests are
3677 sent to the redirector processes. By default all requests
3680 This clause supports both fast and slow acl types.
3681 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
3684 NAME: url_rewrite_bypass redirector_bypass
3686 LOC: Config.onoff.redirector_bypass
3689 When this is 'on', a request will not go through the
3690 redirector if all redirectors are busy. If this is 'off'
3691 and the redirector queue grows too large, Squid will exit
3692 with a FATAL error and ask you to increase the number of
3693 redirectors. You should only enable this if the redirectors
3694 are not critical to your caching system. If you use
3695 redirectors for access control, and you enable this option,
3696 users may have access to pages they should not
3697 be allowed to request.
3701 OPTIONS FOR TUNING THE CACHE
3702 -----------------------------------------------------------------------------
3705 NAME: cache no_cache
3708 LOC: Config.accessList.noCache
3710 A list of ACL elements which, if matched and denied, cause the request to
3711 not be satisfied from the cache and the reply to not be cached.
3712 In other words, use this to force certain objects to never be cached.
3714 You must use the words 'allow' or 'deny' to indicate whether items
3715 matching the ACL should be allowed or denied into the cache.
3717 Default is to allow all to be cached.
3719 This clause supports both fast and slow acl types.
3720 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
3726 LOC: Config.maxStale
3729 This option puts an upper limit on how stale content Squid
3730 will serve from the cache if cache validation fails.
3731 Can be overriden by the refresh_pattern max-stale option.
3734 NAME: refresh_pattern
3735 TYPE: refreshpattern
3739 usage: refresh_pattern [-i] regex min percent max [options]
3741 By default, regular expressions are CASE-SENSITIVE. To make
3742 them case-insensitive, use the -i option.
3744 'Min' is the time (in minutes) an object without an explicit
3745 expiry time should be considered fresh. The recommended
3746 value is 0, any higher values may cause dynamic applications
3747 to be erroneously cached unless the application designer
3748 has taken the appropriate actions.
3750 'Percent' is a percentage of the objects age (time since last
3751 modification age) an object without explicit expiry time
3752 will be considered fresh.
3754 'Max' is an upper limit on how long objects without an explicit
3755 expiry time will be considered fresh.
3757 options: override-expire
3763 ignore-must-revalidate
3770 override-expire enforces min age even if the server
3771 sent an explicit expiry time (e.g., with the
3772 Expires: header or Cache-Control: max-age). Doing this
3773 VIOLATES the HTTP standard. Enabling this feature
3774 could make you liable for problems which it causes.
3776 Note: override-expire does not enforce staleness - it only extends
3777 freshness / min. If the server returns a Expires time which
3778 is longer than your max time, Squid will still consider
3779 the object fresh for that period of time.
3781 override-lastmod enforces min age even on objects
3782 that were modified recently.
3784 reload-into-ims changes client no-cache or ``reload''
3785 to If-Modified-Since requests. Doing this VIOLATES the
3786 HTTP standard. Enabling this feature could make you
3787 liable for problems which it causes.
3789 ignore-reload ignores a client no-cache or ``reload''
3790 header. Doing this VIOLATES the HTTP standard. Enabling
3791 this feature could make you liable for problems which
3794 ignore-no-cache ignores any ``Pragma: no-cache'' and
3795 ``Cache-control: no-cache'' headers received from a server.
3796 The HTTP RFC never allows the use of this (Pragma) header
3797 from a server, only a client, though plenty of servers
3800 ignore-no-store ignores any ``Cache-control: no-store''
3801 headers received from a server. Doing this VIOLATES
3802 the HTTP standard. Enabling this feature could make you
3803 liable for problems which it causes.
3805 ignore-must-revalidate ignores any ``Cache-Control: must-revalidate``
3806 headers received from a server. Doing this VIOLATES
3807 the HTTP standard. Enabling this feature could make you
3808 liable for problems which it causes.
3810 ignore-private ignores any ``Cache-control: private''
3811 headers received from a server. Doing this VIOLATES
3812 the HTTP standard. Enabling this feature could make you
3813 liable for problems which it causes.
3815 ignore-auth caches responses to requests with authorization,
3816 as if the originserver had sent ``Cache-control: public''
3817 in the response header. Doing this VIOLATES the HTTP standard.
3818 Enabling this feature could make you liable for problems which
3821 refresh-ims causes squid to contact the origin server
3822 when a client issues an If-Modified-Since request. This
3823 ensures that the client will receive an updated version
3824 if one is available.
3826 store-stale stores responses even if they don't have explicit
3827 freshness or a validator (i.e., Last-Modified or an ETag)
3828 present, or if they're already stale. By default, Squid will
3829 not cache such responses because they usually can't be
3830 reused. Note that such responses will be stale by default.
3832 max-stale=NN provide a maximum staleness factor. Squid won't
3833 serve objects more stale than this even if it failed to
3834 validate the object. Default: use the max_stale global limit.
3836 Basically a cached object is:
3838 FRESH if expires < now, else STALE
3840 FRESH if lm-factor < percent, else STALE
3844 The refresh_pattern lines are checked in the order listed here.
3845 The first entry which matches is used. If none of the entries
3846 match the default will be used.
3848 Note, you must uncomment all the default lines if you want
3849 to change one. The default setting is only active if none is
3854 # Add any of your own refresh_pattern entries above these.
3855 refresh_pattern ^ftp: 1440 20% 10080
3856 refresh_pattern ^gopher: 1440 0% 1440
3857 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0
3858 refresh_pattern . 0 20% 4320
3862 NAME: quick_abort_min
3866 LOC: Config.quickAbort.min
3869 NAME: quick_abort_max
3873 LOC: Config.quickAbort.max
3876 NAME: quick_abort_pct
3880 LOC: Config.quickAbort.pct
3882 The cache by default continues downloading aborted requests
3883 which are almost completed (less than 16 KB remaining). This
3884 may be undesirable on slow (e.g. SLIP) links and/or very busy
3885 caches. Impatient users may tie up file descriptors and
3886 bandwidth by repeatedly requesting and immediately aborting
3889 When the user aborts a request, Squid will check the
3890 quick_abort values to the amount of data transfered until
3893 If the transfer has less than 'quick_abort_min' KB remaining,
3894 it will finish the retrieval.
3896 If the transfer has more than 'quick_abort_max' KB remaining,
3897 it will abort the retrieval.
3899 If more than 'quick_abort_pct' of the transfer has completed,
3900 it will finish the retrieval.
3902 If you do not want any retrieval to continue after the client
3903 has aborted, set both 'quick_abort_min' and 'quick_abort_max'
3906 If you want retrievals to always continue if they are being
3907 cached set 'quick_abort_min' to '-1 KB'.
3910 NAME: read_ahead_gap
3911 COMMENT: buffer-size
3913 LOC: Config.readAheadGap
3916 The amount of data the cache will buffer ahead of what has been
3917 sent to the client when retrieving an object from another server.
3921 IFDEF: USE_HTTP_VIOLATIONS
3924 LOC: Config.negativeTtl
3927 Set the Default Time-to-Live (TTL) for failed requests.
3928 Certain types of failures (such as "connection refused" and
3929 "404 Not Found") are able to be negatively-cached for a short time.
3930 Modern web servers should provide Expires: header, however if they
3931 do not this can provide a minimum TTL.
3932 The default is not to cache errors with unknown expiry details.
3934 Note that this is different from negative caching of DNS lookups.
3936 WARNING: Doing this VIOLATES the HTTP standard. Enabling
3937 this feature could make you liable for problems which it
3941 NAME: positive_dns_ttl
3944 LOC: Config.positiveDnsTtl
3947 Upper limit on how long Squid will cache positive DNS responses.
3948 Default is 6 hours (360 minutes). This directive must be set
3949 larger than negative_dns_ttl.
3952 NAME: negative_dns_ttl
3955 LOC: Config.negativeDnsTtl
3958 Time-to-Live (TTL) for negative caching of failed DNS lookups.
3959 This also sets the lower cache limit on positive lookups.
3960 Minimum value is 1 second, and it is not recommendable to go
3961 much below 10 seconds.
3964 NAME: range_offset_limit
3965 COMMENT: size [acl acl...]
3967 LOC: Config.rangeOffsetLimit
3970 usage: (size) [units] [[!]aclname]
3972 Sets an upper limit on how far (number of bytes) into the file
3973 a Range request may be to cause Squid to prefetch the whole file.
3974 If beyond this limit, Squid forwards the Range request as it is and
3975 the result is NOT cached.
3977 This is to stop a far ahead range request (lets say start at 17MB)
3978 from making Squid fetch the whole object up to that point before
3979 sending anything to the client.
3981 Multiple range_offset_limit lines may be specified, and they will
3982 be searched from top to bottom on each request until a match is found.
3983 The first match found will be used. If no line matches a request, the
3984 default limit of 0 bytes will be used.
3986 'size' is the limit specified as a number of units.
3988 'units' specifies whether to use bytes, KB, MB, etc.
3989 If no units are specified bytes are assumed.
3991 A size of 0 causes Squid to never fetch more than the
3992 client requested. (default)
3994 A size of 'none' causes Squid to always fetch the object from the
3995 beginning so it may cache the result. (2.0 style)
3997 'aclname' is the name of a defined ACL.
3999 NP: Using 'none' as the byte value here will override any quick_abort settings
4000 that may otherwise apply to the range request. The range request will
4001 be fully fetched from start to finish regardless of the client
4002 actions. This affects bandwidth usage.
4005 NAME: minimum_expiry_time
4008 LOC: Config.minimum_expiry_time
4011 The minimum caching time according to (Expires - Date)
4012 Headers Squid honors if the object can't be revalidated
4013 defaults to 60 seconds. In reverse proxy environments it
4014 might be desirable to honor shorter object lifetimes. It
4015 is most likely better to make your server return a
4016 meaningful Last-Modified header however. In ESI environments
4017 where page fragments often have short lifetimes, this will
4018 often be best set to 0.
4021 NAME: store_avg_object_size
4025 LOC: Config.Store.avgObjectSize
4027 Average object size, used to estimate number of objects your
4028 cache can hold. The default is 13 KB.
4031 NAME: store_objects_per_bucket
4034 LOC: Config.Store.objectsPerBucket
4036 Target number of objects per bucket in the store hash table.
4037 Lowering this value increases the total number of buckets and
4038 also the storage maintenance rate. The default is 20.
4043 -----------------------------------------------------------------------------
4046 NAME: request_header_max_size
4050 LOC: Config.maxRequestHeaderSize
4052 This specifies the maximum size for HTTP headers in a request.
4053 Request headers are usually relatively small (about 512 bytes).
4054 Placing a limit on the request header size will catch certain
4055 bugs (for example with persistent connections) and possibly
4056 buffer-overflow or denial-of-service attacks.
4059 NAME: reply_header_max_size
4063 LOC: Config.maxReplyHeaderSize
4065 This specifies the maximum size for HTTP headers in a reply.
4066 Reply headers are usually relatively small (about 512 bytes).
4067 Placing a limit on the reply header size will catch certain
4068 bugs (for example with persistent connections) and possibly
4069 buffer-overflow or denial-of-service attacks.
4072 NAME: request_body_max_size
4076 LOC: Config.maxRequestBodySize
4078 This specifies the maximum size for an HTTP request body.
4079 In other words, the maximum size of a PUT/POST request.
4080 A user who attempts to send a request with a body larger
4081 than this limit receives an "Invalid Request" error message.
4082 If you set this parameter to a zero (the default), there will
4083 be no limit imposed.
4086 NAME: client_request_buffer_max_size
4090 LOC: Config.maxRequestBufferSize
4092 This specifies the maximum buffer size of a client request.
4093 It prevents squid eating too much memory when somebody uploads
4097 NAME: chunked_request_body_max_size
4101 LOC: Config.maxChunkedRequestBodySize
4103 A broken or confused HTTP/1.1 client may send a chunked HTTP
4104 request to Squid. Squid does not have full support for that
4105 feature yet. To cope with such requests, Squid buffers the
4106 entire request and then dechunks request body to create a
4107 plain HTTP/1.0 request with a known content length. The plain
4108 request is then used by the rest of Squid code as usual.
4110 The option value specifies the maximum size of the buffer used
4111 to hold the request before the conversion. If the chunked
4112 request size exceeds the specified limit, the conversion
4113 fails, and the client receives an "unsupported request" error,
4114 as if dechunking was disabled.
4116 Dechunking is enabled by default. To disable conversion of
4117 chunked requests, set the maximum to zero.
4119 Request dechunking feature and this option in particular are a
4120 temporary hack. When chunking requests and responses are fully
4121 supported, there will be no need to buffer a chunked request.
4125 IFDEF: USE_HTTP_VIOLATIONS
4128 LOC: Config.accessList.brokenPosts
4130 A list of ACL elements which, if matched, causes Squid to send
4131 an extra CRLF pair after the body of a PUT/POST request.
4133 Some HTTP servers has broken implementations of PUT/POST,
4134 and rely on an extra CRLF pair sent by some WWW clients.
4136 Quote from RFC2616 section 4.1 on this matter:
4138 Note: certain buggy HTTP/1.0 client implementations generate an
4139 extra CRLF's after a POST request. To restate what is explicitly
4140 forbidden by the BNF, an HTTP/1.1 client must not preface or follow
4141 a request with an extra CRLF.
4143 This clause only supports fast acl types.
4144 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4147 acl buggy_server url_regex ^http://....
4148 broken_posts allow buggy_server
4151 NAME: adaptation_uses_indirect_client icap_uses_indirect_client
4154 IFDEF: FOLLOW_X_FORWARDED_FOR&&USE_ADAPTATION
4156 LOC: Adaptation::Config::use_indirect_client
4158 Controls whether the indirect client IP address (instead of the direct
4159 client IP address) is passed to adaptation services.
4161 See also: follow_x_forwarded_for adaptation_send_client_ip
4165 IFDEF: USE_HTTP_VIOLATIONS
4169 LOC: Config.onoff.via
4171 If set (default), Squid will include a Via header in requests and
4172 replies as required by RFC2616.
4178 LOC: Config.onoff.ie_refresh
4181 Microsoft Internet Explorer up until version 5.5 Service
4182 Pack 1 has an issue with transparent proxies, wherein it
4183 is impossible to force a refresh. Turning this on provides
4184 a partial fix to the problem, by causing all IMS-REFRESH
4185 requests from older IE versions to check the origin server
4186 for fresh content. This reduces hit ratio by some amount
4187 (~10% in my experience), but allows users to actually get
4188 fresh content when they want it. Note because Squid
4189 cannot tell if the user is using 5.5 or 5.5SP1, the behavior
4190 of 5.5 is unchanged from old versions of Squid (i.e. a
4191 forced refresh is impossible). Newer versions of IE will,
4192 hopefully, continue to have the new behavior and will be
4193 handled based on that assumption. This option defaults to
4194 the old Squid behavior, which is better for hit ratios but
4195 worse for clients using IE, if they need to be able to
4196 force fresh content.
4199 NAME: vary_ignore_expire
4202 LOC: Config.onoff.vary_ignore_expire
4205 Many HTTP servers supporting Vary gives such objects
4206 immediate expiry time with no cache-control header
4207 when requested by a HTTP/1.0 client. This option
4208 enables Squid to ignore such expiry times until
4209 HTTP/1.1 is fully implemented.
4211 WARNING: If turned on this may eventually cause some
4212 varying objects not intended for caching to get cached.
4215 NAME: request_entities
4217 LOC: Config.onoff.request_entities
4220 Squid defaults to deny GET and HEAD requests with request entities,
4221 as the meaning of such requests are undefined in the HTTP standard
4222 even if not explicitly forbidden.
4224 Set this directive to on if you have clients which insists
4225 on sending request entities in GET or HEAD requests. But be warned
4226 that there is server software (both proxies and web servers) which
4227 can fail to properly process this kind of request which may make you
4228 vulnerable to cache pollution attacks if enabled.
4231 NAME: request_header_access
4232 IFDEF: USE_HTTP_VIOLATIONS
4233 TYPE: http_header_access[]
4234 LOC: Config.request_header_access
4237 Usage: request_header_access header_name allow|deny [!]aclname ...
4239 WARNING: Doing this VIOLATES the HTTP standard. Enabling
4240 this feature could make you liable for problems which it
4243 This option replaces the old 'anonymize_headers' and the
4244 older 'http_anonymizer' option with something that is much
4245 more configurable. This new method creates a list of ACLs
4246 for each header, allowing you very fine-tuned header
4249 This option only applies to request headers, i.e., from the
4250 client to the server.
4252 You can only specify known headers for the header name.
4253 Other headers are reclassified as 'Other'. You can also
4254 refer to all the headers with 'All'.
4256 For example, to achieve the same behavior as the old
4257 'http_anonymizer standard' option, you should use:
4259 request_header_access From deny all
4260 request_header_access Referer deny all
4261 request_header_access Server deny all
4262 request_header_access User-Agent deny all
4263 request_header_access WWW-Authenticate deny all
4264 request_header_access Link deny all
4266 Or, to reproduce the old 'http_anonymizer paranoid' feature
4269 request_header_access Allow allow all
4270 request_header_access Authorization allow all
4271 request_header_access WWW-Authenticate allow all
4272 request_header_access Proxy-Authorization allow all
4273 request_header_access Proxy-Authenticate allow all
4274 request_header_access Cache-Control allow all
4275 request_header_access Content-Encoding allow all
4276 request_header_access Content-Length allow all
4277 request_header_access Content-Type allow all
4278 request_header_access Date allow all
4279 request_header_access Expires allow all
4280 request_header_access Host allow all
4281 request_header_access If-Modified-Since allow all
4282 request_header_access Last-Modified allow all
4283 request_header_access Location allow all
4284 request_header_access Pragma allow all
4285 request_header_access Accept allow all
4286 request_header_access Accept-Charset allow all
4287 request_header_access Accept-Encoding allow all
4288 request_header_access Accept-Language allow all
4289 request_header_access Content-Language allow all
4290 request_header_access Mime-Version allow all
4291 request_header_access Retry-After allow all
4292 request_header_access Title allow all
4293 request_header_access Connection allow all
4294 request_header_access All deny all
4296 although many of those are HTTP reply headers, and so should be
4297 controlled with the reply_header_access directive.
4299 By default, all headers are allowed (no anonymizing is
4303 NAME: reply_header_access
4304 IFDEF: USE_HTTP_VIOLATIONS
4305 TYPE: http_header_access[]
4306 LOC: Config.reply_header_access
4309 Usage: reply_header_access header_name allow|deny [!]aclname ...
4311 WARNING: Doing this VIOLATES the HTTP standard. Enabling
4312 this feature could make you liable for problems which it
4315 This option only applies to reply headers, i.e., from the
4316 server to the client.
4318 This is the same as request_header_access, but in the other
4321 This option replaces the old 'anonymize_headers' and the
4322 older 'http_anonymizer' option with something that is much
4323 more configurable. This new method creates a list of ACLs
4324 for each header, allowing you very fine-tuned header
4327 You can only specify known headers for the header name.
4328 Other headers are reclassified as 'Other'. You can also
4329 refer to all the headers with 'All'.
4331 For example, to achieve the same behavior as the old
4332 'http_anonymizer standard' option, you should use:
4334 reply_header_access From deny all
4335 reply_header_access Referer deny all
4336 reply_header_access Server deny all
4337 reply_header_access User-Agent deny all
4338 reply_header_access WWW-Authenticate deny all
4339 reply_header_access Link deny all
4341 Or, to reproduce the old 'http_anonymizer paranoid' feature
4344 reply_header_access Allow allow all
4345 reply_header_access Authorization allow all
4346 reply_header_access WWW-Authenticate allow all
4347 reply_header_access Proxy-Authorization allow all
4348 reply_header_access Proxy-Authenticate allow all
4349 reply_header_access Cache-Control allow all
4350 reply_header_access Content-Encoding allow all
4351 reply_header_access Content-Length allow all
4352 reply_header_access Content-Type allow all
4353 reply_header_access Date allow all
4354 reply_header_access Expires allow all
4355 reply_header_access Host allow all
4356 reply_header_access If-Modified-Since allow all
4357 reply_header_access Last-Modified allow all
4358 reply_header_access Location allow all
4359 reply_header_access Pragma allow all
4360 reply_header_access Accept allow all
4361 reply_header_access Accept-Charset allow all
4362 reply_header_access Accept-Encoding allow all
4363 reply_header_access Accept-Language allow all
4364 reply_header_access Content-Language allow all
4365 reply_header_access Mime-Version allow all
4366 reply_header_access Retry-After allow all
4367 reply_header_access Title allow all
4368 reply_header_access Connection allow all
4369 reply_header_access All deny all
4371 although the HTTP request headers won't be usefully controlled
4372 by this directive -- see request_header_access for details.
4374 By default, all headers are allowed (no anonymizing is
4378 NAME: request_header_replace header_replace
4379 IFDEF: USE_HTTP_VIOLATIONS
4380 TYPE: http_header_replace[]
4381 LOC: Config.request_header_access
4384 Usage: request_header_replace header_name message
4385 Example: request_header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
4387 This option allows you to change the contents of headers
4388 denied with request_header_access above, by replacing them
4389 with some fixed string. This replaces the old fake_user_agent
4392 This only applies to request headers, not reply headers.
4394 By default, headers are removed if denied.
4397 NAME: reply_header_replace
4398 IFDEF: USE_HTTP_VIOLATIONS
4399 TYPE: http_header_replace[]
4400 LOC: Config.reply_header_access
4403 Usage: reply_header_replace header_name message
4404 Example: reply_header_replace Server Foo/1.0
4406 This option allows you to change the contents of headers
4407 denied with reply_header_access above, by replacing them
4408 with some fixed string.
4410 This only applies to reply headers, not request headers.
4412 By default, headers are removed if denied.
4415 NAME: relaxed_header_parser
4416 COMMENT: on|off|warn
4418 LOC: Config.onoff.relaxed_header_parser
4421 In the default "on" setting Squid accepts certain forms
4422 of non-compliant HTTP messages where it is unambiguous
4423 what the sending application intended even if the message
4424 is not correctly formatted. The messages is then normalized
4425 to the correct form when forwarded by Squid.
4427 If set to "warn" then a warning will be emitted in cache.log
4428 each time such HTTP error is encountered.
4430 If set to "off" then such HTTP errors will cause the request
4431 or response to be rejected.
4436 -----------------------------------------------------------------------------
4439 NAME: forward_timeout
4442 LOC: Config.Timeout.forward
4445 This parameter specifies how long Squid should at most attempt in
4446 finding a forwarding path for the request before giving up.
4449 NAME: connect_timeout
4452 LOC: Config.Timeout.connect
4455 This parameter specifies how long to wait for the TCP connect to
4456 the requested server or peer to complete before Squid should
4457 attempt to find another path where to forward the request.
4460 NAME: peer_connect_timeout
4463 LOC: Config.Timeout.peer_connect
4466 This parameter specifies how long to wait for a pending TCP
4467 connection to a peer cache. The default is 30 seconds. You
4468 may also set different timeout values for individual neighbors
4469 with the 'connect-timeout' option on a 'cache_peer' line.
4475 LOC: Config.Timeout.read
4478 The read_timeout is applied on server-side connections. After
4479 each successful read(), the timeout will be extended by this
4480 amount. If no data is read again after this amount of time,
4481 the request is aborted and logged with ERR_READ_TIMEOUT. The
4482 default is 15 minutes.
4488 LOC: Config.Timeout.write
4491 This timeout is tracked for all connections that have data
4492 available for writing and are waiting for the socket to become
4493 ready. After each successful write, the timeout is extended by
4494 the configured amount. If Squid has data to write but the
4495 connection is not ready for the configured duration, the
4496 transaction associated with the connection is terminated. The
4497 default is 15 minutes.
4500 NAME: request_timeout
4502 LOC: Config.Timeout.request
4505 How long to wait for an HTTP request after initial
4506 connection establishment.
4509 NAME: persistent_request_timeout
4511 LOC: Config.Timeout.persistent_request
4514 How long to wait for the next HTTP request on a persistent
4515 connection after the previous request completes.
4518 NAME: client_lifetime
4521 LOC: Config.Timeout.lifetime
4524 The maximum amount of time a client (browser) is allowed to
4525 remain connected to the cache process. This protects the Cache
4526 from having a lot of sockets (and hence file descriptors) tied up
4527 in a CLOSE_WAIT state from remote clients that go away without
4528 properly shutting down (either because of a network failure or
4529 because of a poor client implementation). The default is one
4532 NOTE: The default value is intended to be much larger than any
4533 client would ever need to be connected to your cache. You
4534 should probably change client_lifetime only as a last resort.
4535 If you seem to have many client connections tying up
4536 filedescriptors, we recommend first tuning the read_timeout,
4537 request_timeout, persistent_request_timeout and quick_abort values.
4540 NAME: half_closed_clients
4542 LOC: Config.onoff.half_closed_clients
4545 Some clients may shutdown the sending side of their TCP
4546 connections, while leaving their receiving sides open. Sometimes,
4547 Squid can not tell the difference between a half-closed and a
4548 fully-closed TCP connection.
4550 By default, Squid will immediately close client connections when
4551 read(2) returns "no more data to read."
4553 Change this option to 'on' and Squid will keep open connections
4554 until a read(2) or write(2) on the socket returns an error.
4555 This may show some benefits for reverse proxies. But if not
4556 it is recommended to leave OFF.
4561 LOC: Config.Timeout.pconn
4564 Timeout for idle persistent connections to servers and other
4571 LOC: Ident::TheConfig.timeout
4574 Maximum time to wait for IDENT lookups to complete.
4576 If this is too high, and you enabled IDENT lookups from untrusted
4577 users, you might be susceptible to denial-of-service by having
4578 many ident requests going at once.
4581 NAME: shutdown_lifetime
4584 LOC: Config.shutdownLifetime
4587 When SIGTERM or SIGHUP is received, the cache is put into
4588 "shutdown pending" mode until all active sockets are closed.
4589 This value is the lifetime to set for all open descriptors
4590 during shutdown mode. Any active clients after this many
4591 seconds will receive a 'timeout' message.
4595 ADMINISTRATIVE PARAMETERS
4596 -----------------------------------------------------------------------------
4602 LOC: Config.adminEmail
4604 Email-address of local cache manager who will receive
4605 mail if the cache dies. The default is "webmaster."
4611 LOC: Config.EmailFrom
4613 From: email-address for mail sent when the cache dies.
4614 The default is to use 'appname@unique_hostname'.
4615 Default appname value is "squid", can be changed into
4616 src/globals.h before building squid.
4622 LOC: Config.EmailProgram
4624 Email program used to send mail if the cache dies.
4625 The default is "mail". The specified program must comply
4626 with the standard Unix mail syntax:
4627 mail-program recipient < mailfile
4629 Optional command line options can be specified.
4632 NAME: cache_effective_user
4634 DEFAULT: @DEFAULT_CACHE_EFFECTIVE_USER@
4635 LOC: Config.effectiveUser
4637 If you start Squid as root, it will change its effective/real
4638 UID/GID to the user specified below. The default is to change
4639 to UID of @DEFAULT_CACHE_EFFECTIVE_USER@.
4640 see also; cache_effective_group
4643 NAME: cache_effective_group
4646 LOC: Config.effectiveGroup
4648 Squid sets the GID to the effective user's default group ID
4649 (taken from the password file) and supplementary group list
4650 from the groups membership.
4652 If you want Squid to run with a specific GID regardless of
4653 the group memberships of the effective user then set this
4654 to the group (or GID) you want Squid to run as. When set
4655 all other group privileges of the effective user are ignored
4656 and only this GID is effective. If Squid is not started as
4657 root the user starting Squid MUST be member of the specified
4660 This option is not recommended by the Squid Team.
4661 Our preference is for administrators to configure a secure
4662 user account for squid with UID/GID matching system policies.
4665 NAME: httpd_suppress_version_string
4669 LOC: Config.onoff.httpd_suppress_version_string
4671 Suppress Squid version string info in HTTP headers and HTML error pages.
4674 NAME: visible_hostname
4676 LOC: Config.visibleHostname
4679 If you want to present a special hostname in error messages, etc,
4680 define this. Otherwise, the return value of gethostname()
4681 will be used. If you have multiple caches in a cluster and
4682 get errors about IP-forwarding you must set them to have individual
4683 names with this setting.
4686 NAME: unique_hostname
4688 LOC: Config.uniqueHostname
4691 If you want to have multiple machines with the same
4692 'visible_hostname' you must give each machine a different
4693 'unique_hostname' so forwarding loops can be detected.
4696 NAME: hostname_aliases
4698 LOC: Config.hostnameAliases
4701 A list of other DNS names your cache has.
4709 Minimum umask which should be enforced while the proxy
4710 is running, in addition to the umask set at startup.
4712 For a traditional octal representation of umasks, start
4717 OPTIONS FOR THE CACHE REGISTRATION SERVICE
4718 -----------------------------------------------------------------------------
4720 This section contains parameters for the (optional) cache
4721 announcement service. This service is provided to help
4722 cache administrators locate one another in order to join or
4723 create cache hierarchies.
4725 An 'announcement' message is sent (via UDP) to the registration
4726 service by Squid. By default, the announcement message is NOT
4727 SENT unless you enable it with 'announce_period' below.
4729 The announcement message includes your hostname, plus the
4730 following information from this configuration file:
4736 All current information is processed regularly and made
4737 available on the Web at http://www.ircache.net/Cache/Tracker/.
4740 NAME: announce_period
4742 LOC: Config.Announce.period
4745 This is how frequently to send cache announcements. The
4746 default is `0' which disables sending the announcement
4749 To enable announcing your cache, just set an announce period.
4752 announce_period 1 day
4757 DEFAULT: tracker.ircache.net
4758 LOC: Config.Announce.host
4764 LOC: Config.Announce.file
4770 LOC: Config.Announce.port
4772 announce_host and announce_port set the hostname and port
4773 number where the registration message will be sent.
4775 Hostname will default to 'tracker.ircache.net' and port will
4776 default default to 3131. If the 'filename' argument is given,
4777 the contents of that file will be included in the announce
4782 HTTPD-ACCELERATOR OPTIONS
4783 -----------------------------------------------------------------------------
4786 NAME: httpd_accel_surrogate_id
4789 LOC: Config.Accel.surrogate_id
4791 Surrogates (http://www.esi.org/architecture_spec_1.0.html)
4792 need an identification token to allow control targeting. Because
4793 a farm of surrogates may all perform the same tasks, they may share
4794 an identification token.
4796 The default ID is the visible_hostname
4799 NAME: http_accel_surrogate_remote
4803 LOC: Config.onoff.surrogate_is_remote
4805 Remote surrogates (such as those in a CDN) honour Surrogate-Control: no-store-remote.
4806 Set this to on to have squid behave as a remote surrogate.
4810 IFDEF: USE_SQUID_ESI
4811 COMMENT: libxml2|expat|custom
4813 LOC: ESIParser::Type
4816 ESI markup is not strictly XML compatible. The custom ESI parser
4817 will give higher performance, but cannot handle non ASCII character
4822 DELAY POOL PARAMETERS
4823 -----------------------------------------------------------------------------
4827 TYPE: delay_pool_count
4829 IFDEF: USE_DELAY_POOLS
4832 This represents the number of delay pools to be used. For example,
4833 if you have one class 2 delay pool and one class 3 delays pool, you
4834 have a total of 2 delay pools.
4838 TYPE: delay_pool_class
4840 IFDEF: USE_DELAY_POOLS
4843 This defines the class of each delay pool. There must be exactly one
4844 delay_class line for each delay pool. For example, to define two
4845 delay pools, one of class 2 and one of class 3, the settings above
4849 delay_pools 4 # 4 delay pools
4850 delay_class 1 2 # pool 1 is a class 2 pool
4851 delay_class 2 3 # pool 2 is a class 3 pool
4852 delay_class 3 4 # pool 3 is a class 4 pool
4853 delay_class 4 5 # pool 4 is a class 5 pool
4855 The delay pool classes are:
4857 class 1 Everything is limited by a single aggregate
4860 class 2 Everything is limited by a single aggregate
4861 bucket as well as an "individual" bucket chosen
4862 from bits 25 through 32 of the IPv4 address.
4864 class 3 Everything is limited by a single aggregate
4865 bucket as well as a "network" bucket chosen
4866 from bits 17 through 24 of the IP address and a
4867 "individual" bucket chosen from bits 17 through
4868 32 of the IPv4 address.
4870 class 4 Everything in a class 3 delay pool, with an
4871 additional limit on a per user basis. This
4872 only takes effect if the username is established
4873 in advance - by forcing authentication in your
4876 class 5 Requests are grouped according their tag (see
4877 external_acl's tag= reply).
4880 Each pool also requires a delay_parameters directive to configure the pool size
4881 and speed limits used whenever the pool is applied to a request. Along with
4882 a set of delay_access directives to determine when it is used.
4884 NOTE: If an IP address is a.b.c.d
4885 -> bits 25 through 32 are "d"
4886 -> bits 17 through 24 are "c"
4887 -> bits 17 through 32 are "c * 256 + d"
4889 NOTE-2: Due to the use of bitmasks in class 2,3,4 pools they only apply to
4890 IPv4 traffic. Class 1 and 5 pools may be used with IPv6 traffic.
4894 TYPE: delay_pool_access
4896 IFDEF: USE_DELAY_POOLS
4899 This is used to determine which delay pool a request falls into.
4901 delay_access is sorted per pool and the matching starts with pool 1,
4902 then pool 2, ..., and finally pool N. The first delay pool where the
4903 request is allowed is selected for the request. If it does not allow
4904 the request to any pool then the request is not delayed (default).
4906 For example, if you want some_big_clients in delay
4907 pool 1 and lotsa_little_clients in delay pool 2:
4910 delay_access 1 allow some_big_clients
4911 delay_access 1 deny all
4912 delay_access 2 allow lotsa_little_clients
4913 delay_access 2 deny all
4914 delay_access 3 allow authenticated_clients
4917 NAME: delay_parameters
4918 TYPE: delay_pool_rates
4920 IFDEF: USE_DELAY_POOLS
4923 This defines the parameters for a delay pool. Each delay pool has
4924 a number of "buckets" associated with it, as explained in the
4925 description of delay_class.
4927 For a class 1 delay pool, the syntax is:
4929 delay_parameters pool aggregate
4931 For a class 2 delay pool:
4933 delay_parameters pool aggregate individual
4935 For a class 3 delay pool:
4937 delay_parameters pool aggregate network individual
4939 For a class 4 delay pool:
4941 delay_parameters pool aggregate network individual user
4943 For a class 5 delay pool:
4945 delay_parameters pool tagrate
4947 The option variables are:
4949 pool a pool number - ie, a number between 1 and the
4950 number specified in delay_pools as used in
4953 aggregate the speed limit parameters for the aggregate bucket
4956 individual the speed limit parameters for the individual
4957 buckets (class 2, 3).
4959 network the speed limit parameters for the network buckets
4962 user the speed limit parameters for the user buckets
4965 tagrate the speed limit parameters for the tag buckets
4968 A pair of delay parameters is written restore/maximum, where restore is
4969 the number of bytes (not bits - modem and network speeds are usually
4970 quoted in bits) per second placed into the bucket, and maximum is the
4971 maximum number of bytes which can be in the bucket at any time.
4973 There must be one delay_parameters line for each delay pool.
4976 For example, if delay pool number 1 is a class 2 delay pool as in the
4977 above example, and is being used to strictly limit each host to 64Kbit/sec
4978 (plus overheads), with no overall limit, the line is:
4980 delay_parameters 1 -1/-1 8000/8000
4982 Note that 8 x 8000 KByte/sec -> 64Kbit/sec.
4984 Note that the figure -1 is used to represent "unlimited".
4987 And, if delay pool number 2 is a class 3 delay pool as in the above
4988 example, and you want to limit it to a total of 256Kbit/sec (strict limit)
4989 with each 8-bit network permitted 64Kbit/sec (strict limit) and each
4990 individual host permitted 4800bit/sec with a bucket maximum size of 64Kbits
4991 to permit a decent web page to be downloaded at a decent speed
4992 (if the network is not being limited due to overuse) but slow down
4993 large downloads more significantly:
4995 delay_parameters 2 32000/32000 8000/8000 600/8000
4997 Note that 8 x 32000 KByte/sec -> 256Kbit/sec.
4998 8 x 8000 KByte/sec -> 64Kbit/sec.
4999 8 x 600 Byte/sec -> 4800bit/sec.
5002 Finally, for a class 4 delay pool as in the example - each user will
5003 be limited to 128Kbits/sec no matter how many workstations they are logged into.:
5005 delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000
5008 NAME: delay_initial_bucket_level
5009 COMMENT: (percent, 0-100)
5012 IFDEF: USE_DELAY_POOLS
5013 LOC: Config.Delay.initial
5015 The initial bucket percentage is used to determine how much is put
5016 in each bucket when squid starts, is reconfigured, or first notices
5017 a host accessing it (in class 2 and class 3, individual hosts and
5018 networks only have buckets associated with them once they have been
5023 CLIENT DELAY POOL PARAMETERS
5024 -----------------------------------------------------------------------------
5027 NAME: client_delay_pools
5028 TYPE: client_delay_pool_count
5030 IFDEF: USE_DELAY_POOLS
5031 LOC: Config.ClientDelay
5033 This option specifies the number of client delay pools used. It must
5034 preceed other client_delay_* options.
5037 client_delay_pools 2
5040 NAME: client_delay_initial_bucket_level
5041 COMMENT: (percent, 0-no_limit)
5044 IFDEF: USE_DELAY_POOLS
5045 LOC: Config.ClientDelay.initial
5047 This option determines the initial bucket size as a percentage of
5048 max_bucket_size from client_delay_parameters. Buckets are created
5049 at the time of the "first" connection from the matching IP. Idle
5050 buckets are periodically deleted up.
5052 You can specify more than 100 percent but note that such "oversized"
5053 buckets are not refilled until their size goes down to max_bucket_size
5054 from client_delay_parameters.
5057 client_delay_initial_bucket_level 50
5060 NAME: client_delay_parameters
5061 TYPE: client_delay_pool_rates
5063 IFDEF: USE_DELAY_POOLS
5064 LOC: Config.ClientDelay
5067 This option configures client-side bandwidth limits using the
5070 client_delay_parameters pool speed_limit max_bucket_size
5072 pool is an integer ID used for client_delay_access matching.
5074 speed_limit is bytes added to the bucket per second.
5076 max_bucket_size is the maximum size of a bucket, enforced after any
5077 speed_limit additions.
5079 Please see the delay_parameters option for more information and
5083 client_delay_parameters 1 1024 2048
5084 client_delay_parameters 2 51200 16384
5087 NAME: client_delay_access
5088 TYPE: client_delay_pool_access
5090 IFDEF: USE_DELAY_POOLS
5091 LOC: Config.ClientDelay
5094 This option determines the client-side delay pool for the
5097 client_delay_access pool_ID allow|deny acl_name
5099 All client_delay_access options are checked in their pool ID
5100 order, starting with pool 1. The first checked pool with allowed
5101 request is selected for the request. If no ACL matches or there
5102 are no client_delay_access options, the request bandwidth is not
5105 The ACL-selected pool is then used to find the
5106 client_delay_parameters for the request. Client-side pools are
5107 not used to aggregate clients. Clients are always aggregated
5108 based on their source IP addresses (one bucket per source IP).
5110 Please see delay_access for more examples.
5113 client_delay_access 1 allow low_rate_network
5114 client_delay_access 2 allow vips_network
5118 WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS
5119 -----------------------------------------------------------------------------
5124 LOC: Config.Wccp.router
5128 Use this option to define your WCCP ``home'' router for
5131 wccp_router supports a single WCCP(v1) router
5133 wccp2_router supports multiple WCCPv2 routers
5135 only one of the two may be used at the same time and defines
5136 which version of WCCP to use.
5140 TYPE: IpAddress_list
5141 LOC: Config.Wccp2.router
5145 Use this option to define your WCCP ``home'' router for
5148 wccp_router supports a single WCCP(v1) router
5150 wccp2_router supports multiple WCCPv2 routers
5152 only one of the two may be used at the same time and defines
5153 which version of WCCP to use.
5158 LOC: Config.Wccp.version
5162 This directive is only relevant if you need to set up WCCP(v1)
5163 to some very old and end-of-life Cisco routers. In all other
5164 setups it must be left unset or at the default setting.
5165 It defines an internal version in the WCCP(v1) protocol,
5166 with version 4 being the officially documented protocol.
5168 According to some users, Cisco IOS 11.2 and earlier only
5169 support WCCP version 3. If you're using that or an earlier
5170 version of IOS, you may need to change this value to 3, otherwise
5171 do not specify this parameter.
5174 NAME: wccp2_rebuild_wait
5176 LOC: Config.Wccp2.rebuildwait
5180 If this is enabled Squid will wait for the cache dir rebuild to finish
5181 before sending the first wccp2 HereIAm packet
5184 NAME: wccp2_forwarding_method
5186 LOC: Config.Wccp2.forwarding_method
5190 WCCP2 allows the setting of forwarding methods between the
5191 router/switch and the cache. Valid values are as follows:
5193 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
5194 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
5196 Currently (as of IOS 12.4) cisco routers only support GRE.
5197 Cisco switches only support the L2 redirect assignment method.
5200 NAME: wccp2_return_method
5202 LOC: Config.Wccp2.return_method
5206 WCCP2 allows the setting of return methods between the
5207 router/switch and the cache for packets that the cache
5208 decides not to handle. Valid values are as follows:
5210 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
5211 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
5213 Currently (as of IOS 12.4) cisco routers only support GRE.
5214 Cisco switches only support the L2 redirect assignment.
5216 If the "ip wccp redirect exclude in" command has been
5217 enabled on the cache interface, then it is still safe for
5218 the proxy server to use a l2 redirect method even if this
5219 option is set to GRE.
5222 NAME: wccp2_assignment_method
5224 LOC: Config.Wccp2.assignment_method
5228 WCCP2 allows the setting of methods to assign the WCCP hash
5229 Valid values are as follows:
5231 hash - Hash assignment
5232 mask - Mask assignment
5234 As a general rule, cisco routers support the hash assignment method
5235 and cisco switches support the mask assignment method.
5240 LOC: Config.Wccp2.info
5241 DEFAULT_IF_NONE: standard 0
5244 WCCP2 allows for multiple traffic services. There are two
5245 types: "standard" and "dynamic". The standard type defines
5246 one service id - http (id 0). The dynamic service ids can be from
5247 51 to 255 inclusive. In order to use a dynamic service id
5248 one must define the type of traffic to be redirected; this is done
5249 using the wccp2_service_info option.
5251 The "standard" type does not require a wccp2_service_info option,
5252 just specifying the service id will suffice.
5254 MD5 service authentication can be enabled by adding
5255 "password=<password>" to the end of this service declaration.
5259 wccp2_service standard 0 # for the 'web-cache' standard service
5260 wccp2_service dynamic 80 # a dynamic service type which will be
5261 # fleshed out with subsequent options.
5262 wccp2_service standard 0 password=foo
5265 NAME: wccp2_service_info
5266 TYPE: wccp2_service_info
5267 LOC: Config.Wccp2.info
5271 Dynamic WCCPv2 services require further information to define the
5272 traffic you wish to have diverted.
5276 wccp2_service_info <id> protocol=<protocol> flags=<flag>,<flag>..
5277 priority=<priority> ports=<port>,<port>..
5279 The relevant WCCPv2 flags:
5280 + src_ip_hash, dst_ip_hash
5281 + source_port_hash, dst_port_hash
5282 + src_ip_alt_hash, dst_ip_alt_hash
5283 + src_port_alt_hash, dst_port_alt_hash
5286 The port list can be one to eight entries.
5290 wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source
5291 priority=240 ports=80
5293 Note: the service id must have been defined by a previous
5294 'wccp2_service dynamic <id>' entry.
5299 LOC: Config.Wccp2.weight
5303 Each cache server gets assigned a set of the destination
5304 hash proportional to their weight.
5309 LOC: Config.Wccp.address
5316 LOC: Config.Wccp2.address
5320 Use this option if you require WCCP to use a specific
5323 The default behavior is to not bind to any specific address.
5327 PERSISTENT CONNECTION HANDLING
5328 -----------------------------------------------------------------------------
5330 Also see "pconn_timeout" in the TIMEOUTS section
5333 NAME: client_persistent_connections
5335 LOC: Config.onoff.client_pconns
5339 NAME: server_persistent_connections
5341 LOC: Config.onoff.server_pconns
5344 Persistent connection support for clients and servers. By
5345 default, Squid uses persistent connections (when allowed)
5346 with its clients and servers. You can use these options to
5347 disable persistent connections with clients and/or servers.
5350 NAME: persistent_connection_after_error
5352 LOC: Config.onoff.error_pconns
5355 With this directive the use of persistent connections after
5356 HTTP errors can be disabled. Useful if you have clients
5357 who fail to handle errors on persistent connections proper.
5360 NAME: detect_broken_pconn
5362 LOC: Config.onoff.detect_broken_server_pconns
5365 Some servers have been found to incorrectly signal the use
5366 of HTTP/1.0 persistent connections even on replies not
5367 compatible, causing significant delays. This server problem
5368 has mostly been seen on redirects.
5370 By enabling this directive Squid attempts to detect such
5371 broken replies and automatically assume the reply is finished
5372 after 10 seconds timeout.
5376 CACHE DIGEST OPTIONS
5377 -----------------------------------------------------------------------------
5380 NAME: digest_generation
5381 IFDEF: USE_CACHE_DIGESTS
5383 LOC: Config.onoff.digest_generation
5386 This controls whether the server will generate a Cache Digest
5387 of its contents. By default, Cache Digest generation is
5388 enabled if Squid is compiled with --enable-cache-digests defined.
5391 NAME: digest_bits_per_entry
5392 IFDEF: USE_CACHE_DIGESTS
5394 LOC: Config.digest.bits_per_entry
5397 This is the number of bits of the server's Cache Digest which
5398 will be associated with the Digest entry for a given HTTP
5399 Method and URL (public key) combination. The default is 5.
5402 NAME: digest_rebuild_period
5403 IFDEF: USE_CACHE_DIGESTS
5406 LOC: Config.digest.rebuild_period
5409 This is the wait time between Cache Digest rebuilds.
5412 NAME: digest_rewrite_period
5414 IFDEF: USE_CACHE_DIGESTS
5416 LOC: Config.digest.rewrite_period
5419 This is the wait time between Cache Digest writes to
5423 NAME: digest_swapout_chunk_size
5426 IFDEF: USE_CACHE_DIGESTS
5427 LOC: Config.digest.swapout_chunk_size
5430 This is the number of bytes of the Cache Digest to write to
5431 disk at a time. It defaults to 4096 bytes (4KB), the Squid
5435 NAME: digest_rebuild_chunk_percentage
5436 COMMENT: (percent, 0-100)
5437 IFDEF: USE_CACHE_DIGESTS
5439 LOC: Config.digest.rebuild_chunk_percentage
5442 This is the percentage of the Cache Digest to be scanned at a
5443 time. By default it is set to 10% of the Cache Digest.
5448 -----------------------------------------------------------------------------
5453 LOC: Config.Port.snmp
5457 The port number where Squid listens for SNMP requests. To enable
5458 SNMP support set this to a suitable port number. Port number
5459 3401 is often used for the Squid SNMP agent. By default it's
5460 set to "0" (disabled)
5468 LOC: Config.accessList.snmp
5469 DEFAULT_IF_NONE: deny all
5472 Allowing or denying access to the SNMP port.
5474 All access to the agent is denied by default.
5477 snmp_access allow|deny [!]aclname ...
5479 This clause only supports fast acl types.
5480 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5482 snmp_access allow snmppublic localhost
5483 snmp_access deny all
5486 NAME: snmp_incoming_address
5488 LOC: Config.Addrs.snmp_incoming
5493 NAME: snmp_outgoing_address
5495 LOC: Config.Addrs.snmp_outgoing
5499 Just like 'udp_incoming_address', but for the SNMP port.
5501 snmp_incoming_address is used for the SNMP socket receiving
5502 messages from SNMP agents.
5503 snmp_outgoing_address is used for SNMP packets returned to SNMP
5506 The default snmp_incoming_address is to listen on all
5507 available network interfaces.
5509 If snmp_outgoing_address is not set it will use the same socket
5510 as snmp_incoming_address. Only change this if you want to have
5511 SNMP replies sent using another address than where this Squid
5512 listens for SNMP queries.
5514 NOTE, snmp_incoming_address and snmp_outgoing_address can not have
5515 the same value since they both use port 3401.
5520 -----------------------------------------------------------------------------
5523 NAME: icp_port udp_port
5526 LOC: Config.Port.icp
5528 The port number where Squid sends and receives ICP queries to
5529 and from neighbor caches. The standard UDP port for ICP is 3130.
5530 Default is disabled (0).
5533 icp_port @DEFAULT_ICP_PORT@
5540 LOC: Config.Port.htcp
5542 The port number where Squid sends and receives HTCP queries to
5543 and from neighbor caches. To turn it on you want to set it to
5544 4827. By default it is set to "0" (disabled).
5550 NAME: log_icp_queries
5554 LOC: Config.onoff.log_udp
5556 If set, ICP queries are logged to access.log. You may wish
5557 do disable this if your ICP load is VERY high to speed things
5558 up or to simplify log analysis.
5561 NAME: udp_incoming_address
5563 LOC:Config.Addrs.udp_incoming
5566 udp_incoming_address is used for UDP packets received from other
5569 The default behavior is to not bind to any specific address.
5571 Only change this if you want to have all UDP queries received on
5572 a specific interface/address.
5574 NOTE: udp_incoming_address is used by the ICP, HTCP, and DNS
5575 modules. Altering it will affect all of them in the same manner.
5577 see also; udp_outgoing_address
5579 NOTE, udp_incoming_address and udp_outgoing_address can not
5580 have the same value since they both use the same port.
5583 NAME: udp_outgoing_address
5585 LOC: Config.Addrs.udp_outgoing
5588 udp_outgoing_address is used for UDP packets sent out to other
5591 The default behavior is to not bind to any specific address.
5593 Instead it will use the same socket as udp_incoming_address.
5594 Only change this if you want to have UDP queries sent using another
5595 address than where this Squid listens for UDP queries from other
5598 NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS
5599 modules. Altering it will affect all of them in the same manner.
5601 see also; udp_incoming_address
5603 NOTE, udp_incoming_address and udp_outgoing_address can not
5604 have the same value since they both use the same port.
5611 LOC: Config.onoff.icp_hit_stale
5613 If you want to return ICP_HIT for stale cache objects, set this
5614 option to 'on'. If you have sibling relationships with caches
5615 in other administrative domains, this should be 'off'. If you only
5616 have sibling relationships with caches under your control,
5617 it is probably okay to set this to 'on'.
5618 If set to 'on', your siblings should use the option "allow-miss"
5619 on their cache_peer lines for connecting to you.
5622 NAME: minimum_direct_hops
5625 LOC: Config.minDirectHops
5627 If using the ICMP pinging stuff, do direct fetches for sites
5628 which are no more than this many hops away.
5631 NAME: minimum_direct_rtt
5634 LOC: Config.minDirectRtt
5636 If using the ICMP pinging stuff, do direct fetches for sites
5637 which are no more than this many rtt milliseconds away.
5643 LOC: Config.Netdb.low
5649 LOC: Config.Netdb.high
5651 The low and high water marks for the ICMP measurement
5652 database. These are counts, not percents. The defaults are
5653 900 and 1000. When the high water mark is reached, database
5654 entries will be deleted until the low mark is reached.
5657 NAME: netdb_ping_period
5659 LOC: Config.Netdb.period
5662 The minimum period for measuring a site. There will be at
5663 least this much delay between successive pings to the same
5664 network. The default is five minutes.
5671 LOC: Config.onoff.query_icmp
5673 If you want to ask your peers to include ICMP data in their ICP
5674 replies, enable this option.
5676 If your peer has configured Squid (during compilation) with
5677 '--enable-icmp' that peer will send ICMP pings to origin server
5678 sites of the URLs it receives. If you enable this option the
5679 ICP replies from that peer will include the ICMP data (if available).
5680 Then, when choosing a parent cache, Squid will choose the parent with
5681 the minimal RTT to the origin server. When this happens, the
5682 hierarchy field of the access.log will be
5683 "CLOSEST_PARENT_MISS". This option is off by default.
5686 NAME: test_reachability
5690 LOC: Config.onoff.test_reachability
5692 When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
5693 instead of ICP_MISS if the target host is NOT in the ICMP
5694 database, or has a zero RTT.
5697 NAME: icp_query_timeout
5701 LOC: Config.Timeout.icp_query
5703 Normally Squid will automatically determine an optimal ICP
5704 query timeout value based on the round-trip-time of recent ICP
5705 queries. If you want to override the value determined by
5706 Squid, set this 'icp_query_timeout' to a non-zero value. This
5707 value is specified in MILLISECONDS, so, to use a 2-second
5708 timeout (the old default), you would write:
5710 icp_query_timeout 2000
5713 NAME: maximum_icp_query_timeout
5717 LOC: Config.Timeout.icp_query_max
5719 Normally the ICP query timeout is determined dynamically. But
5720 sometimes it can lead to very large values (say 5 seconds).
5721 Use this option to put an upper limit on the dynamic timeout
5722 value. Do NOT use this option to always use a fixed (instead
5723 of a dynamic) timeout value. To set a fixed timeout see the
5724 'icp_query_timeout' directive.
5727 NAME: minimum_icp_query_timeout
5731 LOC: Config.Timeout.icp_query_min
5733 Normally the ICP query timeout is determined dynamically. But
5734 sometimes it can lead to very small timeouts, even lower than
5735 the normal latency variance on your link due to traffic.
5736 Use this option to put an lower limit on the dynamic timeout
5737 value. Do NOT use this option to always use a fixed (instead
5738 of a dynamic) timeout value. To set a fixed timeout see the
5739 'icp_query_timeout' directive.
5742 NAME: background_ping_rate
5746 LOC: Config.backgroundPingRate
5748 Controls how often the ICP pings are sent to siblings that
5749 have background-ping set.
5753 MULTICAST ICP OPTIONS
5754 -----------------------------------------------------------------------------
5759 LOC: Config.mcast_group_list
5762 This tag specifies a list of multicast groups which your server
5763 should join to receive multicasted ICP queries.
5765 NOTE! Be very careful what you put here! Be sure you
5766 understand the difference between an ICP _query_ and an ICP
5767 _reply_. This option is to be set only if you want to RECEIVE
5768 multicast queries. Do NOT set this option to SEND multicast
5769 ICP (use cache_peer for that). ICP replies are always sent via
5770 unicast, so this option does not affect whether or not you will
5771 receive replies from multicast group members.
5773 You must be very careful to NOT use a multicast address which
5774 is already in use by another group of caches.
5776 If you are unsure about multicast, please read the Multicast
5777 chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
5779 Usage: mcast_groups 239.128.16.128 224.0.1.20
5781 By default, Squid doesn't listen on any multicast groups.
5784 NAME: mcast_miss_addr
5785 IFDEF: MULTICAST_MISS_STREAM
5787 LOC: Config.mcast_miss.addr
5790 If you enable this option, every "cache miss" URL will
5791 be sent out on the specified multicast address.
5793 Do not enable this option unless you are are absolutely
5794 certain you understand what you are doing.
5797 NAME: mcast_miss_ttl
5798 IFDEF: MULTICAST_MISS_STREAM
5800 LOC: Config.mcast_miss.ttl
5803 This is the time-to-live value for packets multicasted
5804 when multicasting off cache miss URLs is enabled. By
5805 default this is set to 'site scope', i.e. 16.
5808 NAME: mcast_miss_port
5809 IFDEF: MULTICAST_MISS_STREAM
5811 LOC: Config.mcast_miss.port
5814 This is the port number to be used in conjunction with
5818 NAME: mcast_miss_encode_key
5819 IFDEF: MULTICAST_MISS_STREAM
5821 LOC: Config.mcast_miss.encode_key
5822 DEFAULT: XXXXXXXXXXXXXXXX
5824 The URLs that are sent in the multicast miss stream are
5825 encrypted. This is the encryption key.
5828 NAME: mcast_icp_query_timeout
5832 LOC: Config.Timeout.mcast_icp_query
5834 For multicast peers, Squid regularly sends out ICP "probes" to
5835 count how many other peers are listening on the given multicast
5836 address. This value specifies how long Squid should wait to
5837 count all the replies. The default is 2000 msec, or 2
5842 INTERNAL ICON OPTIONS
5843 -----------------------------------------------------------------------------
5846 NAME: icon_directory
5848 LOC: Config.icons.directory
5849 DEFAULT: @DEFAULT_ICON_DIR@
5851 Where the icons are stored. These are normally kept in
5855 NAME: global_internal_static
5857 LOC: Config.onoff.global_internal_static
5860 This directive controls is Squid should intercept all requests for
5861 /squid-internal-static/ no matter which host the URL is requesting
5862 (default on setting), or if nothing special should be done for
5863 such URLs (off setting). The purpose of this directive is to make
5864 icons etc work better in complex cache hierarchies where it may
5865 not always be possible for all corners in the cache mesh to reach
5866 the server generating a directory listing.
5869 NAME: short_icon_urls
5871 LOC: Config.icons.use_short_names
5874 If this is enabled Squid will use short URLs for icons.
5875 If disabled it will revert to the old behavior of including
5876 it's own name and port in the URL.
5878 If you run a complex cache hierarchy with a mix of Squid and
5879 other proxies you may need to disable this directive.
5884 -----------------------------------------------------------------------------
5887 NAME: error_directory
5889 LOC: Config.errorDirectory
5892 If you wish to create your own versions of the default
5893 error files to customize them to suit your company copy
5894 the error/template files to another directory and point
5897 WARNING: This option will disable multi-language support
5898 on error pages if used.
5900 The squid developers are interested in making squid available in
5901 a wide variety of languages. If you are making translations for a
5902 language that Squid does not currently provide please consider
5903 contributing your translation back to the project.
5904 http://wiki.squid-cache.org/Translations
5906 The squid developers working on translations are happy to supply drop-in
5907 translated error files in exchange for any new language contributions.
5910 NAME: error_default_language
5911 IFDEF: USE_ERR_LOCALES
5913 LOC: Config.errorDefaultLanguage
5916 Set the default language which squid will send error pages in
5917 if no existing translation matches the clients language
5920 If unset (default) generic English will be used.
5922 The squid developers are interested in making squid available in
5923 a wide variety of languages. If you are interested in making
5924 translations for any language see the squid wiki for details.
5925 http://wiki.squid-cache.org/Translations
5928 NAME: error_log_languages
5929 IFDEF: USE_ERR_LOCALES
5931 LOC: Config.errorLogMissingLanguages
5934 Log to cache.log what languages users are attempting to
5935 auto-negotiate for translations.
5937 Successful negotiations are not logged. Only failures
5938 have meaning to indicate that Squid may need an upgrade
5939 of its error page translations.
5942 NAME: err_page_stylesheet
5944 LOC: Config.errorStylesheet
5945 DEFAULT: @DEFAULT_CONFIG_DIR@/errorpage.css
5947 CSS Stylesheet to pattern the display of Squid default error pages.
5949 For information on CSS see http://www.w3.org/Style/CSS/
5954 LOC: Config.errHtmlText
5957 HTML text to include in error messages. Make this a "mailto"
5958 URL to your admin address, or maybe just a link to your
5959 organizations Web page.
5961 To include this in your error messages, you must rewrite
5962 the error template files (found in the "errors" directory).
5963 Wherever you want the 'err_html_text' line to appear,
5964 insert a %L tag in the error template file.
5967 NAME: email_err_data
5970 LOC: Config.onoff.emailErrData
5973 If enabled, information about the occurred error will be
5974 included in the mailto links of the ERR pages (if %W is set)
5975 so that the email body contains the data.
5976 Syntax is <A HREF="mailto:%w%W">%w</A>
5981 LOC: Config.denyInfoList
5984 Usage: deny_info err_page_name acl
5985 or deny_info http://... acl
5986 or deny_info TCP_RESET acl
5988 This can be used to return a ERR_ page for requests which
5989 do not pass the 'http_access' rules. Squid remembers the last
5990 acl it evaluated in http_access, and if a 'deny_info' line exists
5991 for that ACL Squid returns a corresponding error page.
5993 The acl is typically the last acl on the http_access deny line which
5994 denied access. The exceptions to this rule are:
5995 - When Squid needs to request authentication credentials. It's then
5996 the first authentication related acl encountered
5997 - When none of the http_access lines matches. It's then the last
5998 acl processed on the last http_access line.
5999 - When the decision to deny access was made by an adaptation service,
6000 the acl name is the corresponding eCAP or ICAP service_name.
6002 NP: If providing your own custom error pages with error_directory
6003 you may also specify them by your custom file name:
6004 Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
6006 By defaut Squid will send "403 Forbidden". A different 4xx or 5xx
6007 may be specified by prefixing the file name with the code and a colon.
6008 e.g. 404:ERR_CUSTOM_ACCESS_DENIED
6010 Alternatively you can tell Squid to reset the TCP connection
6011 by specifying TCP_RESET.
6013 Or you can specify an error URL or URL pattern. The browsers will
6014 get redirected to the specified URL after formatting tags have
6015 been replaced. Redirect will be done with 302 or 307 according to
6016 HTTP/1.1 specs. A different 3xx code may be specified by prefixing
6017 the URL. e.g. 303:http://example.com/
6020 %a - username (if available. Password NOT included)
6023 %E - Error description
6025 %H - Request domain name
6026 %i - Client IP Address
6028 %o - Message result from external ACL helper
6029 %p - Request Port number
6030 %P - Request Protocol name
6031 %R - Request URL path
6032 %T - Timestamp in RFC 1123 format
6033 %U - Full canonical URL from client
6034 (HTTPS URLs terminate with *)
6035 %u - Full canonical URL from client
6036 %w - Admin email from squid.conf
6038 %% - Literal percent (%) code
6043 OPTIONS INFLUENCING REQUEST FORWARDING
6044 -----------------------------------------------------------------------------
6047 NAME: nonhierarchical_direct
6049 LOC: Config.onoff.nonhierarchical_direct
6052 By default, Squid will send any non-hierarchical requests
6053 (matching hierarchy_stoplist or not cacheable request type) direct
6056 If you set this to off, Squid will prefer to send these
6057 requests to parents.
6059 Note that in most configurations, by turning this off you will only
6060 add latency to these request without any improvement in global hit
6063 If you are inside an firewall see never_direct instead of
6069 LOC: Config.onoff.prefer_direct
6072 Normally Squid tries to use parents for most requests. If you for some
6073 reason like it to first try going direct and only use a parent if
6074 going direct fails set this to on.
6076 By combining nonhierarchical_direct off and prefer_direct on you
6077 can set up Squid to use a parent as a backup path if going direct
6080 Note: If you want Squid to use parents for all requests see
6081 the never_direct directive. prefer_direct only modifies how Squid
6082 acts on cacheable requests.
6087 LOC: Config.accessList.AlwaysDirect
6090 Usage: always_direct allow|deny [!]aclname ...
6092 Here you can use ACL elements to specify requests which should
6093 ALWAYS be forwarded by Squid to the origin servers without using
6094 any peers. For example, to always directly forward requests for
6095 local servers ignoring any parents or siblings you may have use
6098 acl local-servers dstdomain my.domain.net
6099 always_direct allow local-servers
6101 To always forward FTP requests directly, use
6104 always_direct allow FTP
6106 NOTE: There is a similar, but opposite option named
6107 'never_direct'. You need to be aware that "always_direct deny
6108 foo" is NOT the same thing as "never_direct allow foo". You
6109 may need to use a deny rule to exclude a more-specific case of
6110 some other rule. Example:
6112 acl local-external dstdomain external.foo.net
6113 acl local-servers dstdomain .foo.net
6114 always_direct deny local-external
6115 always_direct allow local-servers
6117 NOTE: If your goal is to make the client forward the request
6118 directly to the origin server bypassing Squid then this needs
6119 to be done in the client configuration. Squid configuration
6120 can only tell Squid how Squid should fetch the object.
6122 NOTE: This directive is not related to caching. The replies
6123 is cached as usual even if you use always_direct. To not cache
6124 the replies see the 'cache' directive.
6126 This clause supports both fast and slow acl types.
6127 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6132 LOC: Config.accessList.NeverDirect
6135 Usage: never_direct allow|deny [!]aclname ...
6137 never_direct is the opposite of always_direct. Please read
6138 the description for always_direct if you have not already.
6140 With 'never_direct' you can use ACL elements to specify
6141 requests which should NEVER be forwarded directly to origin
6142 servers. For example, to force the use of a proxy for all
6143 requests, except those in your local domain use something like:
6145 acl local-servers dstdomain .foo.net
6146 never_direct deny local-servers
6147 never_direct allow all
6149 or if Squid is inside a firewall and there are local intranet
6150 servers inside the firewall use something like:
6152 acl local-intranet dstdomain .foo.net
6153 acl local-external dstdomain external.foo.net
6154 always_direct deny local-external
6155 always_direct allow local-intranet
6156 never_direct allow all
6158 This clause supports both fast and slow acl types.
6159 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
6163 ADVANCED NETWORKING OPTIONS
6164 -----------------------------------------------------------------------------
6167 NAME: incoming_icp_average
6170 LOC: Config.comm_incoming.icp_average
6173 NAME: incoming_http_average
6176 LOC: Config.comm_incoming.http_average
6179 NAME: incoming_dns_average
6182 LOC: Config.comm_incoming.dns_average
6185 NAME: min_icp_poll_cnt
6188 LOC: Config.comm_incoming.icp_min_poll
6191 NAME: min_dns_poll_cnt
6194 LOC: Config.comm_incoming.dns_min_poll
6197 NAME: min_http_poll_cnt
6200 LOC: Config.comm_incoming.http_min_poll
6202 Heavy voodoo here. I can't even believe you are reading this.
6203 Are you crazy? Don't even think about adjusting these unless
6204 you understand the algorithms in comm_select.c first!
6210 LOC: Config.accept_filter
6214 The name of an accept(2) filter to install on Squid's
6215 listen socket(s). This feature is perhaps specific to
6216 FreeBSD and requires support in the kernel.
6218 The 'httpready' filter delays delivering new connections
6219 to Squid until a full HTTP request has been received.
6220 See the accf_http(9) man page for details.
6222 The 'dataready' filter delays delivering new connections
6223 to Squid until there is some data to process.
6224 See the accf_dataready(9) man page for details.
6228 The 'data' filter delays delivering of new connections
6229 to Squid until there is some data to process by TCP_ACCEPT_DEFER.
6230 You may optionally specify a number of seconds to wait by
6231 'data=N' where N is the number of seconds. Defaults to 30
6232 if not specified. See the tcp(7) man page for details.
6235 accept_filter httpready
6240 NAME: client_ip_max_connections
6242 LOC: Config.client_ip_max_connections
6245 Set an absolute limit on the number of connections a single
6246 client IP can use. Any more than this and Squid will begin to drop
6247 new connections from the client until it closes some links.
6249 Note that this is a global limit. It affects all HTTP, HTCP, Gopher and FTP
6250 connections from the client. For finer control use the ACL access controls.
6252 Requires client_db to be enabled (the default).
6254 WARNING: This may noticably slow down traffic received via external proxies
6255 or NAT devices and cause them to rebound error messages back to their clients.
6258 NAME: tcp_recv_bufsize
6262 LOC: Config.tcpRcvBufsz
6264 Size of receive buffer to set for TCP sockets. Probably just
6265 as easy to change your kernel's default. Set to zero to use
6266 the default buffer size.
6271 -----------------------------------------------------------------------------
6278 LOC: Adaptation::Icap::TheConfig.onoff
6281 If you want to enable the ICAP module support, set this to on.
6284 NAME: icap_connect_timeout
6287 LOC: Adaptation::Icap::TheConfig.connect_timeout_raw
6290 This parameter specifies how long to wait for the TCP connect to
6291 the requested ICAP server to complete before giving up and either
6292 terminating the HTTP transaction or bypassing the failure.
6294 The default for optional services is peer_connect_timeout.
6295 The default for essential services is connect_timeout.
6296 If this option is explicitly set, its value applies to all services.
6299 NAME: icap_io_timeout
6303 LOC: Adaptation::Icap::TheConfig.io_timeout_raw
6306 This parameter specifies how long to wait for an I/O activity on
6307 an established, active ICAP connection before giving up and
6308 either terminating the HTTP transaction or bypassing the
6311 The default is read_timeout.
6314 NAME: icap_service_failure_limit
6315 COMMENT: limit [in memory-depth time-units]
6316 TYPE: icap_service_failure_limit
6318 LOC: Adaptation::Icap::TheConfig
6321 The limit specifies the number of failures that Squid tolerates
6322 when establishing a new TCP connection with an ICAP service. If
6323 the number of failures exceeds the limit, the ICAP service is
6324 not used for new ICAP requests until it is time to refresh its
6327 A negative value disables the limit. Without the limit, an ICAP
6328 service will not be considered down due to connectivity failures
6329 between ICAP OPTIONS requests.
6331 Squid forgets ICAP service failures older than the specified
6332 value of memory-depth. The memory fading algorithm
6333 is approximate because Squid does not remember individual
6334 errors but groups them instead, splitting the option
6335 value into ten time slots of equal length.
6337 When memory-depth is 0 and by default this option has no
6338 effect on service failure expiration.
6340 Squid always forgets failures when updating service settings
6341 using an ICAP OPTIONS transaction, regardless of this option
6345 # suspend service usage after 10 failures in 5 seconds:
6346 icap_service_failure_limit 10 in 5 seconds
6349 NAME: icap_service_revival_delay
6352 LOC: Adaptation::Icap::TheConfig.service_revival_delay
6355 The delay specifies the number of seconds to wait after an ICAP
6356 OPTIONS request failure before requesting the options again. The
6357 failed ICAP service is considered "down" until fresh OPTIONS are
6360 The actual delay cannot be smaller than the hardcoded minimum
6361 delay of 30 seconds.
6364 NAME: icap_preview_enable
6368 LOC: Adaptation::Icap::TheConfig.preview_enable
6371 The ICAP Preview feature allows the ICAP server to handle the
6372 HTTP message by looking only at the beginning of the message body
6373 or even without receiving the body at all. In some environments,
6374 previews greatly speedup ICAP processing.
6376 During an ICAP OPTIONS transaction, the server may tell Squid what
6377 HTTP messages should be previewed and how big the preview should be.
6378 Squid will not use Preview if the server did not request one.
6380 To disable ICAP Preview for all ICAP services, regardless of
6381 individual ICAP server OPTIONS responses, set this option to "off".
6383 icap_preview_enable off
6386 NAME: icap_preview_size
6389 LOC: Adaptation::Icap::TheConfig.preview_size
6392 The default size of preview data to be sent to the ICAP server.
6393 -1 means no preview. This value might be overwritten on a per server
6394 basis by OPTIONS requests.
6397 NAME: icap_206_enable
6401 LOC: Adaptation::Icap::TheConfig.allow206_enable
6404 206 (Partial Content) responses is an ICAP extension that allows the
6405 ICAP agents to optionally combine adapted and original HTTP message
6406 content. The decision to combine is postponed until the end of the
6407 ICAP response. Squid supports Partial Content extension by default.
6409 Activation of the Partial Content extension is negotiated with each
6410 ICAP service during OPTIONS exchange. Most ICAP servers should handle
6411 negotation correctly even if they do not support the extension, but
6412 some might fail. To disable Partial Content support for all ICAP
6413 services and to avoid any negotiation, set this option to "off".
6419 NAME: icap_default_options_ttl
6422 LOC: Adaptation::Icap::TheConfig.default_options_ttl
6425 The default TTL value for ICAP OPTIONS responses that don't have
6426 an Options-TTL header.
6429 NAME: icap_persistent_connections
6433 LOC: Adaptation::Icap::TheConfig.reuse_connections
6436 Whether or not Squid should use persistent connections to
6440 NAME: adaptation_send_client_ip icap_send_client_ip
6442 IFDEF: USE_ADAPTATION
6444 LOC: Adaptation::Config::send_client_ip
6447 If enabled, Squid shares HTTP client IP information with adaptation
6448 services. For ICAP, Squid adds the X-Client-IP header to ICAP requests.
6449 For eCAP, Squid sets the libecap::metaClientIp transaction option.
6451 See also: adaptation_uses_indirect_client
6454 NAME: adaptation_send_username icap_send_client_username
6456 IFDEF: USE_ADAPTATION
6458 LOC: Adaptation::Config::send_username
6461 This sends authenticated HTTP client username (if available) to
6462 the adaptation service.
6464 For ICAP, the username value is encoded based on the
6465 icap_client_username_encode option and is sent using the header
6466 specified by the icap_client_username_header option.
6469 NAME: icap_client_username_header
6472 LOC: Adaptation::Icap::TheConfig.client_username_header
6473 DEFAULT: X-Client-Username
6475 ICAP request header name to use for adaptation_send_username.
6478 NAME: icap_client_username_encode
6482 LOC: Adaptation::Icap::TheConfig.client_username_encode
6485 Whether to base64 encode the authenticated client username.
6489 TYPE: icap_service_type
6491 LOC: Adaptation::Icap::TheConfig
6494 Defines a single ICAP service using the following format:
6496 icap_service service_name vectoring_point [options] service_url
6499 an opaque identifier which must be unique in squid.conf
6501 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
6502 This specifies at which point of transaction processing the
6503 ICAP service should be activated. *_postcache vectoring points
6504 are not yet supported.
6506 service_url: icap://servername:port/servicepath
6507 ICAP server and service location.
6509 ICAP does not allow a single service to handle both REQMOD and RESPMOD
6510 transactions. Squid does not enforce that requirement. You can specify
6511 services with the same service_url and different vectoring_points. You
6512 can even specify multiple identical services as long as their
6513 service_names differ.
6516 Service options are separated by white space. ICAP services support
6517 the following name=value options:
6520 If set to 'on' or '1', the ICAP service is treated as
6521 optional. If the service cannot be reached or malfunctions,
6522 Squid will try to ignore any errors and process the message as
6523 if the service was not enabled. No all ICAP errors can be
6524 bypassed. If set to 0, the ICAP service is treated as
6525 essential and all ICAP errors will result in an error page
6526 returned to the HTTP client.
6528 Bypass is off by default: services are treated as essential.
6531 If set to 'on' or '1', the ICAP service is allowed to
6532 dynamically change the current message adaptation plan by
6533 returning a chain of services to be used next. The services
6534 are specified using the X-Next-Services ICAP response header
6535 value, formatted as a comma-separated list of service names.
6536 Each named service should be configured in squid.conf and
6537 should have the same method and vectoring point as the current
6538 ICAP transaction. Services violating these rules are ignored.
6539 An empty X-Next-Services value results in an empty plan which
6540 ends the current adaptation.
6542 Routing is not allowed by default: the ICAP X-Next-Services
6543 response header is ignored.
6546 Only has effect on split-stack systems. The default on those systems
6547 is to use IPv4-only connections. When set to 'on' this option will
6548 make Squid use IPv6-only connections to contact this ICAP service.
6550 on-overload=block|bypass|wait|force
6551 If the service Max-Connections limit has been reached, do
6552 one of the following for each new ICAP transaction:
6553 * block: send an HTTP error response to the client
6554 * bypass: ignore the "over-connected" ICAP service
6555 * wait: wait (in a FIFO queue) for an ICAP connection slot
6556 * force: proceed, ignoring the Max-Connections limit
6558 In SMP mode with N workers, each worker assumes the service
6559 connection limit is Max-Connections/N, even though not all
6560 workers may use a given service.
6562 The default value is "bypass" if service is bypassable,
6563 otherwise it is set to "wait".
6567 Use the given number as the Max-Connections limit, regardless
6568 of the Max-Connections value given by the service, if any.
6570 Older icap_service format without optional named parameters is
6571 deprecated but supported for backward compatibility.
6574 icap_service svcBlocker reqmod_precache bypass=0 icap://icap1.mydomain.net:1344/reqmod
6575 icap_service svcLogger reqmod_precache routing=on icap://icap2.mydomain.net:1344/respmod
6579 TYPE: icap_class_type
6584 This deprecated option was documented to define an ICAP service
6585 chain, even though it actually defined a set of similar, redundant
6586 services, and the chains were not supported.
6588 To define a set of redundant services, please use the
6589 adaptation_service_set directive. For service chains, use
6590 adaptation_service_chain.
6594 TYPE: icap_access_type
6599 This option is deprecated. Please use adaptation_access, which
6600 has the same ICAP functionality, but comes with better
6601 documentation, and eCAP support.
6606 -----------------------------------------------------------------------------
6613 LOC: Adaptation::Ecap::TheConfig.onoff
6616 Controls whether eCAP support is enabled.
6620 TYPE: ecap_service_type
6622 LOC: Adaptation::Ecap::TheConfig
6625 Defines a single eCAP service
6627 ecap_service servicename vectoring_point bypass service_url
6629 vectoring_point = reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
6630 This specifies at which point of transaction processing the
6631 eCAP service should be activated. *_postcache vectoring points
6632 are not yet supported.
6634 If set to 1, the eCAP service is treated as optional. If the
6635 service cannot be reached or malfunctions, Squid will try to
6636 ignore any errors and process the message as if the service
6637 was not enabled. No all eCAP errors can be bypassed.
6638 If set to 0, the eCAP service is treated as essential and all
6639 eCAP errors will result in an error page returned to the
6641 service_url = ecap://vendor/service_name?custom&cgi=style¶meters=optional
6644 ecap_service service_1 reqmod_precache 0 ecap://filters-R-us/leakDetector?on_error=block
6645 ecap_service service_2 respmod_precache 1 icap://filters-R-us/virusFilter?config=/etc/vf.cfg
6648 NAME: loadable_modules
6650 IFDEF: USE_LOADABLE_MODULES
6651 LOC: Config.loadable_module_names
6654 Instructs Squid to load the specified dynamic module(s) or activate
6655 preloaded module(s).
6657 loadable_modules @DEFAULT_PREFIX@/lib/MinimalAdapter.so
6661 MESSAGE ADAPTATION OPTIONS
6662 -----------------------------------------------------------------------------
6665 NAME: adaptation_service_set
6666 TYPE: adaptation_service_set_type
6667 IFDEF: USE_ADAPTATION
6672 Configures an ordered set of similar, redundant services. This is
6673 useful when hot standby or backup adaptation servers are available.
6675 adaptation_service_set set_name service_name1 service_name2 ...
6677 The named services are used in the set declaration order. The first
6678 applicable adaptation service from the set is used first. The next
6679 applicable service is tried if and only if the transaction with the
6680 previous service fails and the message waiting to be adapted is still
6683 When adaptation starts, broken services are ignored as if they were
6684 not a part of the set. A broken service is a down optional service.
6686 The services in a set must be attached to the same vectoring point
6687 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
6689 If all services in a set are optional then adaptation failures are
6690 bypassable. If all services in the set are essential, then a
6691 transaction failure with one service may still be retried using
6692 another service from the set, but when all services fail, the master
6693 transaction fails as well.
6695 A set may contain a mix of optional and essential services, but that
6696 is likely to lead to surprising results because broken services become
6697 ignored (see above), making previously bypassable failures fatal.
6698 Technically, it is the bypassability of the last failed service that
6701 See also: adaptation_access adaptation_service_chain
6704 adaptation_service_set svcBlocker urlFilterPrimary urlFilterBackup
6705 adaptation service_set svcLogger loggerLocal loggerRemote
6708 NAME: adaptation_service_chain
6709 TYPE: adaptation_service_chain_type
6710 IFDEF: USE_ADAPTATION
6715 Configures a list of complementary services that will be applied
6716 one-by-one, forming an adaptation chain or pipeline. This is useful
6717 when Squid must perform different adaptations on the same message.
6719 adaptation_service_chain chain_name service_name1 svc_name2 ...
6721 The named services are used in the chain declaration order. The first
6722 applicable adaptation service from the chain is used first. The next
6723 applicable service is applied to the successful adaptation results of
6724 the previous service in the chain.
6726 When adaptation starts, broken services are ignored as if they were
6727 not a part of the chain. A broken service is a down optional service.
6729 Request satisfaction terminates the adaptation chain because Squid
6730 does not currently allow declaration of RESPMOD services at the
6731 "reqmod_precache" vectoring point (see icap_service or ecap_service).
6733 The services in a chain must be attached to the same vectoring point
6734 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
6736 A chain may contain a mix of optional and essential services. If an
6737 essential adaptation fails (or the failure cannot be bypassed for
6738 other reasons), the master transaction fails. Otherwise, the failure
6739 is bypassed as if the failed adaptation service was not in the chain.
6741 See also: adaptation_access adaptation_service_set
6744 adaptation_service_chain svcRequest requestLogger urlFilter leakDetector
6747 NAME: adaptation_access
6748 TYPE: adaptation_access_type
6749 IFDEF: USE_ADAPTATION
6753 Sends an HTTP transaction to an ICAP or eCAP adaptation service.
6755 adaptation_access service_name allow|deny [!]aclname...
6756 adaptation_access set_name allow|deny [!]aclname...
6758 At each supported vectoring point, the adaptation_access
6759 statements are processed in the order they appear in this
6760 configuration file. Statements pointing to the following services
6761 are ignored (i.e., skipped without checking their ACL):
6763 - services serving different vectoring points
6764 - "broken-but-bypassable" services
6765 - "up" services configured to ignore such transactions
6766 (e.g., based on the ICAP Transfer-Ignore header).
6768 When a set_name is used, all services in the set are checked
6769 using the same rules, to find the first applicable one. See
6770 adaptation_service_set for details.
6772 If an access list is checked and there is a match, the
6773 processing stops: For an "allow" rule, the corresponding
6774 adaptation service is used for the transaction. For a "deny"
6775 rule, no adaptation service is activated.
6777 It is currently not possible to apply more than one adaptation
6778 service at the same vectoring point to the same HTTP transaction.
6780 See also: icap_service and ecap_service
6783 adaptation_access service_1 allow all
6786 NAME: adaptation_service_iteration_limit
6788 IFDEF: USE_ADAPTATION
6789 LOC: Adaptation::Config::service_iteration_limit
6792 Limits the number of iterations allowed when applying adaptation
6793 services to a message. If your longest adaptation set or chain
6794 may have more than 16 services, increase the limit beyond its
6795 default value of 16. If detecting infinite iteration loops sooner
6796 is critical, make the iteration limit match the actual number
6797 of services in your longest adaptation set or chain.
6799 Infinite adaptation loops are most likely with routing services.
6801 See also: icap_service routing=1
6804 NAME: adaptation_masterx_shared_names
6806 IFDEF: USE_ADAPTATION
6807 LOC: Adaptation::Config::masterx_shared_name
6810 For each master transaction (i.e., the HTTP request and response
6811 sequence, including all related ICAP and eCAP exchanges), Squid
6812 maintains a table of metadata. The table entries are (name, value)
6813 pairs shared among eCAP and ICAP exchanges. The table is destroyed
6814 with the master transaction.
6816 This option specifies the table entry names that Squid must accept
6817 from and forward to the adaptation transactions.
6819 An ICAP REQMOD or RESPMOD transaction may set an entry in the
6820 shared table by returning an ICAP header field with a name
6821 specified in adaptation_masterx_shared_names.
6823 An eCAP REQMOD or RESPMOD transaction may set an entry in the
6824 shared table by implementing the libecap::visitEachOption() API
6825 to provide an option with a name specified in
6826 adaptation_masterx_shared_names.
6828 Squid will store and forward the set entry to subsequent adaptation
6829 transactions within the same master transaction scope.
6831 Only one shared entry name is supported at this time.
6834 # share authentication information among ICAP services
6835 adaptation_masterx_shared_names X-Subscriber-ID
6841 LOC: Adaptation::Icap::TheConfig.repeat
6842 DEFAULT_IF_NONE: deny all
6844 This ACL determines which retriable ICAP transactions are
6845 retried. Transactions that received a complete ICAP response
6846 and did not have to consume or produce HTTP bodies to receive
6847 that response are usually retriable.
6849 icap_retry allow|deny [!]aclname ...
6851 Squid automatically retries some ICAP I/O timeouts and errors
6852 due to persistent connection race conditions.
6854 See also: icap_retry_limit
6857 NAME: icap_retry_limit
6860 LOC: Adaptation::Icap::TheConfig.repeat_limit
6863 Limits the number of retries allowed. When set to zero (default),
6864 no retries are allowed.
6866 Communication errors due to persistent connection race
6867 conditions are unavoidable, automatically retried, and do not
6868 count against this limit.
6870 See also: icap_retry
6876 -----------------------------------------------------------------------------
6879 NAME: check_hostnames
6882 LOC: Config.onoff.check_hostnames
6884 For security and stability reasons Squid can check
6885 hostnames for Internet standard RFC compliance. If you want
6886 Squid to perform these checks turn this directive on.
6889 NAME: allow_underscore
6892 LOC: Config.onoff.allow_underscore
6894 Underscore characters is not strictly allowed in Internet hostnames
6895 but nevertheless used by many sites. Set this to off if you want
6896 Squid to be strict about the standard.
6897 This check is performed only when check_hostnames is set to on.
6900 NAME: cache_dns_program
6902 IFDEF: USE_DNSSERVERS
6903 DEFAULT: @DEFAULT_DNSSERVER@
6904 LOC: Config.Program.dnsserver
6906 Specify the location of the executable for dnslookup process.
6910 TYPE: HelperChildConfig
6911 IFDEF: USE_DNSSERVERS
6912 DEFAULT: 32 startup=1 idle=1
6913 LOC: Config.dnsChildren
6915 The maximum number of processes spawn to service DNS name lookups.
6916 If you limit it too few Squid will have to wait for them to process
6917 a backlog of requests, slowing it down. If you allow too many they
6918 will use RAM and other system resources noticably.
6919 The maximum this may be safely set to is 32.
6921 The startup= and idle= options allow some measure of skew in your
6926 Sets a minimum of how many processes are to be spawned when Squid
6927 starts or reconfigures. When set to zero the first request will
6928 cause spawning of the first child process to handle it.
6930 Starting too few will cause an initial slowdown in traffic as Squid
6931 attempts to simultaneously spawn enough processes to cope.
6935 Sets a minimum of how many processes Squid is to try and keep available
6936 at all times. When traffic begins to rise above what the existing
6937 processes can handle this many more will be spawned up to the maximum
6938 configured. A minimum setting of 1 is required.
6941 NAME: dns_retransmit_interval
6944 LOC: Config.Timeout.idns_retransmit
6945 IFDEF: !USE_DNSSERVERS
6947 Initial retransmit interval for DNS queries. The interval is
6948 doubled each time all configured DNS servers have been tried.
6954 LOC: Config.Timeout.idns_query
6955 IFDEF: !USE_DNSSERVERS
6957 DNS Query timeout. If no response is received to a DNS query
6958 within this time all DNS servers for the queried domain
6959 are assumed to be unavailable.
6962 NAME: dns_packet_max
6965 LOC: Config.dns.packet_max
6966 IFDEF: !USE_DNSSERVERS
6968 Maximum number of bytes packet size to advertise via EDNS.
6969 Set to "none" to disable EDNS large packet support.
6971 For legacy reasons DNS UDP replies will default to 512 bytes which
6972 is too small for many responses. EDNS provides a means for Squid to
6973 negotiate receiving larger responses back immediately without having
6974 to failover with repeat requests. Responses larger than this limit
6975 will retain the old behaviour of failover to TCP DNS.
6977 Squid has no real fixed limit internally, but allowing packet sizes
6978 over 1500 bytes requires network jumbogram support and is usually not
6981 WARNING: The RFC also indicates that some older resolvers will reply
6982 with failure of the whole request if the extension is added. Some
6983 resolvers have already been identified which will reply with mangled
6984 EDNS response on occasion. Usually in response to many-KB jumbogram
6985 sizes being advertised by Squid.
6986 Squid will currently treat these both as an unable-to-resolve domain
6987 even if it would be resolvable without EDNS.
6994 LOC: Config.onoff.res_defnames
6996 Normally the RES_DEFNAMES resolver option is disabled
6997 (see res_init(3)). This prevents caches in a hierarchy
6998 from interpreting single-component hostnames locally. To allow
6999 Squid to handle single-component names, enable this option.
7002 NAME: dns_nameservers
7005 LOC: Config.dns_nameservers
7007 Use this if you want to specify a list of DNS name servers
7008 (IP addresses) to use instead of those given in your
7009 /etc/resolv.conf file.
7010 On Windows platforms, if no value is specified here or in
7011 the /etc/resolv.conf file, the list of DNS name servers are
7012 taken from the Windows registry, both static and dynamic DHCP
7013 configurations are supported.
7015 Example: dns_nameservers 10.0.0.1 192.172.0.4
7020 DEFAULT: @DEFAULT_HOSTS@
7021 LOC: Config.etcHostsPath
7023 Location of the host-local IP name-address associations
7024 database. Most Operating Systems have such a file on different
7026 - Un*X & Linux: /etc/hosts
7027 - Windows NT/2000: %SystemRoot%\system32\drivers\etc\hosts
7028 (%SystemRoot% value install default is c:\winnt)
7029 - Windows XP/2003: %SystemRoot%\system32\drivers\etc\hosts
7030 (%SystemRoot% value install default is c:\windows)
7031 - Windows 9x/Me: %windir%\hosts
7032 (%windir% value is usually c:\windows)
7033 - Cygwin: /etc/hosts
7035 The file contains newline-separated definitions, in the
7036 form ip_address_in_dotted_form name [name ...] names are
7037 whitespace-separated. Lines beginning with an hash (#)
7038 character are comments.
7040 The file is checked at startup and upon configuration.
7041 If set to 'none', it won't be checked.
7042 If append_domain is used, that domain will be added to
7043 domain-local (i.e. not containing any dot character) host
7049 LOC: Config.appendDomain
7052 Appends local domain name to hostnames without any dots in
7053 them. append_domain must begin with a period.
7055 Be warned there are now Internet names with no dots in
7056 them using only top-domain names, so setting this may
7057 cause some Internet sites to become unavailable.
7060 append_domain .yourdomain.com
7063 NAME: ignore_unknown_nameservers
7065 LOC: Config.onoff.ignore_unknown_nameservers
7068 By default Squid checks that DNS responses are received
7069 from the same IP addresses they are sent to. If they
7070 don't match, Squid ignores the response and writes a warning
7071 message to cache.log. You can allow responses from unknown
7072 nameservers by setting this option to 'off'.
7075 NAME: dns_v4_fallback
7078 LOC: Config.onoff.dns_require_A
7080 Standard practice with DNS is to lookup either A or AAAA records
7081 and use the results if it succeeds. Only looking up the other if
7082 the first attempt fails or otherwise produces no results.
7084 That policy however will cause squid to produce error pages for some
7085 servers that advertise AAAA but are unreachable over IPv6.
7087 If this is ON squid will always lookup both AAAA and A, using both.
7088 If this is OFF squid will lookup AAAA and only try A if none found.
7090 WARNING: There are some possibly unwanted side-effects with this on:
7091 *) Doubles the load placed by squid on the DNS network.
7092 *) May negatively impact connection delay times.
7096 COMMENT: (number of entries)
7099 LOC: Config.ipcache.size
7106 LOC: Config.ipcache.low
7113 LOC: Config.ipcache.high
7115 The size, low-, and high-water marks for the IP cache.
7118 NAME: fqdncache_size
7119 COMMENT: (number of entries)
7122 LOC: Config.fqdncache.size
7124 Maximum number of FQDN cache entries.
7129 -----------------------------------------------------------------------------
7136 LOC: Config.onoff.mem_pools
7138 If set, Squid will keep pools of allocated (but unused) memory
7139 available for future use. If memory is a premium on your
7140 system and you believe your malloc library outperforms Squid
7141 routines, disable this.
7144 NAME: memory_pools_limit
7148 LOC: Config.MemPools.limit
7150 Used only with memory_pools on:
7151 memory_pools_limit 50 MB
7153 If set to a non-zero value, Squid will keep at most the specified
7154 limit of allocated (but unused) memory in memory pools. All free()
7155 requests that exceed this limit will be handled by your malloc
7156 library. Squid does not pre-allocate any memory, just safe-keeps
7157 objects that otherwise would be free()d. Thus, it is safe to set
7158 memory_pools_limit to a reasonably high value even if your
7159 configuration will use less memory.
7161 If set to none, Squid will keep all memory it can. That is, there
7162 will be no limit on the total amount of memory used for safe-keeping.
7164 To disable memory allocation optimization, do not set
7165 memory_pools_limit to 0 or none. Set memory_pools to "off" instead.
7167 An overhead for maintaining memory pools is not taken into account
7168 when the limit is checked. This overhead is close to four bytes per
7169 object kept. However, pools may actually _save_ memory because of
7170 reduced memory thrashing in your malloc library.
7174 COMMENT: on|off|transparent|truncate|delete
7177 LOC: opt_forwarded_for
7179 If set to "on", Squid will append your client's IP address
7180 in the HTTP requests it forwards. By default it looks like:
7182 X-Forwarded-For: 192.1.2.3
7184 If set to "off", it will appear as
7186 X-Forwarded-For: unknown
7188 If set to "transparent", Squid will not alter the
7189 X-Forwarded-For header in any way.
7191 If set to "delete", Squid will delete the entire
7192 X-Forwarded-For header.
7194 If set to "truncate", Squid will remove all existing
7195 X-Forwarded-For entries, and place the client IP as the sole entry.
7198 NAME: cachemgr_passwd
7199 TYPE: cachemgrpasswd
7201 LOC: Config.passwd_list
7203 Specify passwords for cachemgr operations.
7205 Usage: cachemgr_passwd password action action ...
7207 Some valid actions are (see cache manager menu for a full list):
7247 * Indicates actions which will not be performed without a
7248 valid password, others can be performed if not listed here.
7250 To disable an action, set the password to "disable".
7251 To allow performing an action without a password, set the
7254 Use the keyword "all" to set the same password for all actions.
7257 cachemgr_passwd secret shutdown
7258 cachemgr_passwd lesssssssecret info stats/objects
7259 cachemgr_passwd disable all
7266 LOC: Config.onoff.client_db
7268 If you want to disable collecting per-client statistics,
7269 turn off client_db here.
7272 NAME: refresh_all_ims
7276 LOC: Config.onoff.refresh_all_ims
7278 When you enable this option, squid will always check
7279 the origin server for an update when a client sends an
7280 If-Modified-Since request. Many browsers use IMS
7281 requests when the user requests a reload, and this
7282 ensures those clients receive the latest version.
7284 By default (off), squid may return a Not Modified response
7285 based on the age of the cached version.
7288 NAME: reload_into_ims
7289 IFDEF: USE_HTTP_VIOLATIONS
7293 LOC: Config.onoff.reload_into_ims
7295 When you enable this option, client no-cache or ``reload''
7296 requests will be changed to If-Modified-Since requests.
7297 Doing this VIOLATES the HTTP standard. Enabling this
7298 feature could make you liable for problems which it
7301 see also refresh_pattern for a more selective approach.
7304 NAME: maximum_single_addr_tries
7306 LOC: Config.retry.maxtries
7309 This sets the maximum number of connection attempts for a
7310 host that only has one address (for multiple-address hosts,
7311 each address is tried once).
7313 The default value is one attempt, the (not recommended)
7314 maximum is 255 tries. A warning message will be generated
7315 if it is set to a value greater than ten.
7317 Note: This is in addition to the request re-forwarding which
7318 takes place if Squid fails to get a satisfying response.
7321 NAME: retry_on_error
7323 LOC: Config.retry.onerror
7326 If set to on Squid will automatically retry requests when
7327 receiving an error response. This is mainly useful if you
7328 are in a complex cache hierarchy to work around access
7332 NAME: as_whois_server
7334 LOC: Config.as_whois_server
7335 DEFAULT: whois.ra.net
7337 WHOIS server to query for AS numbers. NOTE: AS numbers are
7338 queried only when Squid starts up, not for every request.
7343 LOC: Config.onoff.offline
7346 Enable this option and Squid will never try to validate cached
7350 NAME: uri_whitespace
7351 TYPE: uri_whitespace
7352 LOC: Config.uri_whitespace
7355 What to do with requests that have whitespace characters in the
7358 strip: The whitespace characters are stripped out of the URL.
7359 This is the behavior recommended by RFC2396.
7360 deny: The request is denied. The user receives an "Invalid
7362 allow: The request is allowed and the URI is not changed. The
7363 whitespace characters remain in the URI. Note the
7364 whitespace is passed to redirector processes if they
7366 encode: The request is allowed and the whitespace characters are
7367 encoded according to RFC1738. This could be considered
7368 a violation of the HTTP/1.1
7369 RFC because proxies are not allowed to rewrite URI's.
7370 chop: The request is allowed and the URI is chopped at the
7371 first whitespace. This might also be considered a
7377 LOC: Config.chroot_dir
7380 Specifies a directory where Squid should do a chroot() while
7381 initializing. This also causes Squid to fully drop root
7382 privileges after initializing. This means, for example, if you
7383 use a HTTP port less than 1024 and try to reconfigure, you may
7384 get an error saying that Squid can not open the port.
7387 NAME: balance_on_multiple_ip
7389 LOC: Config.onoff.balance_on_multiple_ip
7392 Modern IP resolvers in squid sort lookup results by preferred access.
7393 By default squid will use these IP in order and only rotates to
7394 the next listed when the most preffered fails.
7396 Some load balancing servers based on round robin DNS have been
7397 found not to preserve user session state across requests
7398 to different IP addresses.
7400 Enabling this directive Squid rotates IP's per request.
7403 NAME: pipeline_prefetch
7405 LOC: Config.onoff.pipeline_prefetch
7408 To boost the performance of pipelined requests to closer
7409 match that of a non-proxied environment Squid can try to fetch
7410 up to two requests in parallel from a pipeline.
7412 Defaults to off for bandwidth management and access logging
7415 WARNING: pipelining breaks NTLM and Negotiate/Kerberos authentication.
7418 NAME: high_response_time_warning
7421 LOC: Config.warnings.high_rptm
7424 If the one-minute median response time exceeds this value,
7425 Squid prints a WARNING with debug level 0 to get the
7426 administrators attention. The value is in milliseconds.
7429 NAME: high_page_fault_warning
7431 LOC: Config.warnings.high_pf
7434 If the one-minute average page fault rate exceeds this
7435 value, Squid prints a WARNING with debug level 0 to get
7436 the administrators attention. The value is in page faults
7440 NAME: high_memory_warning
7442 LOC: Config.warnings.high_memory
7445 If the memory usage (as determined by mallinfo) exceeds
7446 this amount, Squid prints a WARNING with debug level 0 to get
7447 the administrators attention.
7450 NAME: sleep_after_fork
7451 COMMENT: (microseconds)
7453 LOC: Config.sleep_after_fork
7456 When this is set to a non-zero value, the main Squid process
7457 sleeps the specified number of microseconds after a fork()
7458 system call. This sleep may help the situation where your
7459 system reports fork() failures due to lack of (virtual)
7460 memory. Note, however, if you have a lot of child
7461 processes, these sleep delays will add up and your
7462 Squid will not service requests for some amount of time
7463 until all the child processes have been started.
7464 On Windows value less then 1000 (1 milliseconds) are
7468 NAME: windows_ipaddrchangemonitor
7469 IFDEF: _SQUID_MSWIN_
7473 LOC: Config.onoff.WIN32_IpAddrChangeMonitor
7475 On Windows Squid by default will monitor IP address changes and will
7476 reconfigure itself after any detected event. This is very useful for
7477 proxies connected to internet with dial-up interfaces.
7478 In some cases (a Proxy server acting as VPN gateway is one) it could be
7479 desiderable to disable this behaviour setting this to 'off'.
7480 Note: after changing this, Squid service must be restarted.
7485 IFDEF: USE_SQUID_EUI
7487 LOC: Eui::TheConfig.euiLookup
7489 Whether to lookup the EUI or MAC address of a connected client.
7492 NAME: max_filedescriptors max_filedesc
7495 LOC: Config.max_filedescriptors
7497 The maximum number of filedescriptors supported.
7499 The default "0" means Squid inherits the current ulimit setting.
7501 Note: Changing this requires a restart of Squid. Also
7502 not all comm loops supports large values.
7510 Number of main Squid processes or "workers" to fork and maintain.
7511 0: "no daemon" mode, like running "squid -N ..."
7512 1: "no SMP" mode, start one main Squid process daemon (default)
7513 N: start N main Squid process daemons (i.e., SMP mode)
7515 In SMP mode, each worker does nearly all what a single Squid daemon
7516 does (e.g., listen on http_port and forward HTTP requests).
7519 NAME: cpu_affinity_map
7520 TYPE: CpuAffinityMap
7521 LOC: Config.cpuAffinityMap
7524 Usage: cpu_affinity_map process_numbers=P1,P2,... cores=C1,C2,...
7526 Sets 1:1 mapping between Squid processes and CPU cores. For example,
7528 cpu_affinity_map process_numbers=1,2,3,4 cores=1,3,5,7
7530 affects processes 1 through 4 only and places them on the first
7531 four even cores, starting with core #1.
7533 CPU cores are numbered starting from 1. Requires support for
7534 sched_getaffinity(2) and sched_setaffinity(2) system calls.
7536 Multiple cpu_affinity_map options are merged.