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
63 OPTIONS FOR AUTHENTICATION
64 -----------------------------------------------------------------------------
72 This is used to define parameters for the various authentication
73 schemes supported by Squid.
75 format: auth_param scheme parameter [setting]
77 The order in which authentication schemes are presented to the client is
78 dependent on the order the scheme first appears in config file. IE
79 has a bug (it's not RFC 2617 compliant) in that it will use the basic
80 scheme if basic is the first entry presented, even if more secure
81 schemes are presented. For now use the order in the recommended
82 settings section below. If other browsers have difficulties (don't
83 recognize the schemes offered even if you are using basic) either
84 put basic first, or disable the other schemes (by commenting out their
87 Once an authentication scheme is fully configured, it can only be
88 shutdown by shutting squid down and restarting. Changes can be made on
89 the fly and activated with a reconfigure. I.E. You can change to a
90 different helper, but not unconfigure the helper completely.
92 Please note that while this directive defines how Squid processes
93 authentication it does not automatically activate authentication.
94 To use authentication you must in addition make use of ACLs based
95 on login name in http_access (proxy_auth, proxy_auth_regex or
96 external with %LOGIN used in the format tag). The browser will be
97 challenged for authentication on the first such acl encountered
98 in http_access processing and will also be re-challenged for new
99 login credentials if the request is being denied by a proxy_auth
102 WARNING: authentication can't be used in a transparently intercepting
103 proxy as the client then thinks it is talking to an origin server and
104 not the proxy. This is a limitation of bending the TCP/IP protocol to
105 transparently intercepting port 80, not a limitation in Squid.
106 Ports flagged 'transparent', 'intercept', or 'tproxy' have
107 authentication disabled.
109 === Parameters for the basic scheme follow. ===
112 Specify the command for the external authenticator. Such a program
113 reads a line containing "username password" and replies "OK" or
114 "ERR" in an endless loop. "ERR" responses may optionally be followed
115 by a error description available as %m in the returned error page.
116 If you use an authenticator, make sure you have 1 acl of type
119 By default, the basic authentication scheme is not used unless a
120 program is specified.
122 If you want to use the traditional NCSA proxy authentication, set
123 this line to something like
125 auth_param basic program @DEFAULT_PREFIX@/libexec/ncsa_auth @DEFAULT_PREFIX@/etc/passwd
128 HTTP uses iso-latin-1 as characterset, while some authentication
129 backends such as LDAP expects UTF-8. If this is set to on Squid will
130 translate the HTTP iso-latin-1 charset to UTF-8 before sending the
131 username & password to the helper.
133 "children" numberofchildren [startup=N] [idle=N] [concurrency=N]
134 The maximum number of authenticator processes to spawn. If you start too few
135 Squid will have to wait for them to process a backlog of credential
136 verifications, slowing it down. When password verifications are
137 done via a (slow) network you are likely to need lots of
138 authenticator processes.
140 The startup= and idle= options permit some skew in the exact amount
141 run. A minimum of startup=N will begin during startup and reconfigure
142 and Squid will start more in groups of up to idle=N in an attempt to meet
143 traffic needs and to keep idle=N free above those traffic needs up to
146 The concurrency= option sets the number of concurrent requests the
147 helper can process. The default of 0 is used for helpers who only
148 supports one request at a time. Setting this to a number greater than
149 0 changes the protocol used to include a channel number first on the
150 request/response line, allowing multiple requests to be sent to the
151 same helper in parallell without wating for the response.
152 Must not be set unless it's known the helper supports this.
154 auth_param basic children 20 startup=0 idle=1
157 Specifies the realm name which is to be reported to the
158 client for the basic proxy authentication scheme (part of
159 the text the user will see when prompted their username and
160 password). There is no default.
161 auth_param basic realm Squid proxy-caching web server
163 "credentialsttl" timetolive
164 Specifies how long squid assumes an externally validated
165 username:password pair is valid for - in other words how
166 often the helper program is called for that user. Set this
167 low to force revalidation with short lived passwords. Note
168 setting this high does not impact your susceptibility
169 to replay attacks unless you are using an one-time password
170 system (such as SecureID). If you are using such a system,
171 you will be vulnerable to replay attacks unless you also
172 use the max_user_ip ACL in an http_access rule.
174 "casesensitive" on|off
175 Specifies if usernames are case sensitive. Most user databases are
176 case insensitive allowing the same username to be spelled using both
177 lower and upper case letters, but some are case sensitive. This
178 makes a big difference for user_max_ip ACL processing and similar.
179 auth_param basic casesensitive off
181 === Parameters for the digest scheme follow ===
184 Specify the command for the external authenticator. Such
185 a program reads a line containing "username":"realm" and
186 replies with the appropriate H(A1) value hex encoded or
187 ERR if the user (or his H(A1) hash) does not exists.
188 See rfc 2616 for the definition of H(A1).
189 "ERR" responses may optionally be followed by a error description
190 available as %m in the returned error page.
192 By default, the digest authentication scheme is not used unless a
193 program is specified.
195 If you want to use a digest authenticator, set this line to
198 auth_param digest program @DEFAULT_PREFIX@/bin/digest_pw_auth @DEFAULT_PREFIX@/etc/digpass
201 HTTP uses iso-latin-1 as characterset, while some authentication
202 backends such as LDAP expects UTF-8. If this is set to on Squid will
203 translate the HTTP iso-latin-1 charset to UTF-8 before sending the
204 username & password to the helper.
206 "children" numberofchildren [startup=N] [idle=N] [concurrency=N]
207 The maximum number of authenticator processes to spawn (default 5).
208 If you start too few Squid will have to wait for them to
209 process a backlog of H(A1) calculations, slowing it down.
210 When the H(A1) calculations are done via a (slow) network
211 you are likely to need lots of authenticator processes.
213 The startup= and idle= options permit some skew in the exact amount
214 run. A minimum of startup=N will begin during startup and reconfigure
215 and Squid will start more in groups of up to idle=N in an attempt to meet
216 traffic needs and to keep idle=N free above those traffic needs up to
219 The concurrency= option sets the number of concurrent requests the
220 helper can process. The default of 0 is used for helpers who only
221 supports one request at a time. Setting this to a number greater than
222 0 changes the protocol used to include a channel number first on the
223 request/response line, allowing multiple requests to be sent to the
224 same helper in parallell without wating for the response.
225 Must not be set unless it's known the helper supports this.
227 auth_param digest children 20 startup=0 idle=1
230 Specifies the realm name which is to be reported to the
231 client for the digest proxy authentication scheme (part of
232 the text the user will see when prompted their username and
233 password). There is no default.
234 auth_param digest realm Squid proxy-caching web server
236 "nonce_garbage_interval" timeinterval
237 Specifies the interval that nonces that have been issued
238 to client_agent's are checked for validity.
240 "nonce_max_duration" timeinterval
241 Specifies the maximum length of time a given nonce will be
244 "nonce_max_count" number
245 Specifies the maximum number of times a given nonce can be
248 "nonce_strictness" on|off
249 Determines if squid requires strict increment-by-1 behavior
250 for nonce counts, or just incrementing (off - for use when
251 useragents generate nonce counts that occasionally miss 1
252 (ie, 1,2,4,6)). Default off.
254 "check_nonce_count" on|off
255 This directive if set to off can disable the nonce count check
256 completely to work around buggy digest qop implementations in
257 certain mainstream browser versions. Default on to check the
258 nonce count to protect from authentication replay attacks.
260 "post_workaround" on|off
261 This is a workaround to certain buggy browsers who sends
262 an incorrect request digest in POST requests when reusing
263 the same nonce as acquired earlier on a GET request.
265 === NTLM scheme options follow ===
268 Specify the command for the external NTLM authenticator.
269 Such a program reads exchanged NTLMSSP packets with
270 the browser via Squid until authentication is completed.
271 If you use an NTLM authenticator, make sure you have 1 acl
272 of type proxy_auth. By default, the NTLM authenticator_program
275 auth_param ntlm program @DEFAULT_PREFIX@/bin/ntlm_auth
277 "children" numberofchildren [startup=N] [idle=N]
278 The maximum number of authenticator processes to spawn (default 5).
279 If you start too few Squid will have to wait for them to
280 process a backlog of credential verifications, slowing it
281 down. When credential verifications are done via a (slow)
282 network you are likely to need lots of authenticator
285 The startup= and idle= options permit some skew in the exact amount
286 run. A minimum of startup=N will begin during startup and reconfigure
287 and Squid will start more in groups of up to idle=N in an attempt to meet
288 traffic needs and to keep idle=N free above those traffic needs up to
291 auth_param ntlm children 20 startup=0 idle=1
294 If you experience problems with PUT/POST requests when using the
295 Negotiate authentication scheme then you can try setting this to
296 off. This will cause Squid to forcibly close the connection on
297 the initial requests where the browser asks which schemes are
298 supported by the proxy.
300 auth_param ntlm keep_alive on
302 === Options for configuring the NEGOTIATE auth-scheme follow ===
305 Specify the command for the external Negotiate authenticator.
306 This protocol is used in Microsoft Active-Directory enabled setups with
307 the Microsoft Internet Explorer or Mozilla Firefox browsers.
308 Its main purpose is to exchange credentials with the Squid proxy
309 using the Kerberos mechanisms.
310 If you use a Negotiate authenticator, make sure you have at least
311 one acl of type proxy_auth active. By default, the negotiate
312 authenticator_program is not used.
313 The only supported program for this role is the ntlm_auth
314 program distributed as part of Samba, version 4 or later.
316 auth_param negotiate program @DEFAULT_PREFIX@/bin/ntlm_auth --helper-protocol=gss-spnego
318 "children" numberofchildren [startup=N] [idle=N]
319 The maximum number of authenticator processes to spawn (default 5).
320 If you start too few Squid will have to wait for them to
321 process a backlog of credential verifications, slowing it
322 down. When crendential verifications are done via a (slow)
323 network you are likely to need lots of authenticator
326 The startup= and idle= options permit some skew in the exact amount
327 run. A minimum of startup=N will begin during startup and reconfigure
328 and Squid will start more in groups of up to idle=N in an attempt to meet
329 traffic needs and to keep idle=N free above those traffic needs up to
332 auth_param negotiate children 20 startup=0 idle=1
335 If you experience problems with PUT/POST requests when using the
336 Negotiate authentication scheme then you can try setting this to
337 off. This will cause Squid to forcibly close the connection on
338 the initial requests where the browser asks which schemes are
339 supported by the proxy.
341 auth_param negotiate keep_alive on
346 #Recommended minimum configuration per scheme:
347 #auth_param negotiate program <uncomment and complete this line to activate>
348 #auth_param negotiate children 20 startup=0 idle=1
349 #auth_param negotiate keep_alive on
351 #auth_param ntlm program <uncomment and complete this line to activate>
352 #auth_param ntlm children 20 startup=0 idle=1
353 #auth_param ntlm keep_alive on
355 #auth_param digest program <uncomment and complete this line>
356 #auth_param digest children 20 startup=0 idle=1
357 #auth_param digest realm Squid proxy-caching web server
358 #auth_param digest nonce_garbage_interval 5 minutes
359 #auth_param digest nonce_max_duration 30 minutes
360 #auth_param digest nonce_max_count 50
362 #auth_param basic program <uncomment and complete this line>
363 #auth_param basic children 5 stratup=5 idle=1
364 #auth_param basic realm Squid proxy-caching web server
365 #auth_param basic credentialsttl 2 hours
368 NAME: authenticate_cache_garbage_interval
371 LOC: Config.authenticateGCInterval
373 The time period between garbage collection across the username cache.
374 This is a tradeoff between memory utilization (long intervals - say
375 2 days) and CPU (short intervals - say 1 minute). Only change if you
379 NAME: authenticate_ttl
382 LOC: Config.authenticateTTL
384 The time a user & their credentials stay in the logged in
385 user cache since their last request. When the garbage
386 interval passes, all user credentials that have passed their
387 TTL are removed from memory.
390 NAME: authenticate_ip_ttl
392 LOC: Config.authenticateIpTTL
395 If you use proxy authentication and the 'max_user_ip' ACL,
396 this directive controls how long Squid remembers the IP
397 addresses associated with each user. Use a small value
398 (e.g., 60 seconds) if your users might change addresses
399 quickly, as is the case with dialups. You might be safe
400 using a larger value (e.g., 2 hours) in a corporate LAN
401 environment with relatively static address assignments.
406 -----------------------------------------------------------------------------
409 NAME: external_acl_type
410 TYPE: externalAclHelper
411 LOC: Config.externalAclHelperList
414 This option defines external acl classes using a helper program
415 to look up the status
417 external_acl_type name [options] FORMAT.. /path/to/helper [helper arguments..]
421 ttl=n TTL in seconds for cached results (defaults to 3600
424 TTL for cached negative lookups (default same
427 Maximum number of acl helper processes spawned to service
428 external acl lookups of this type. (default 20)
430 Minimum number of acl helper processes to spawn during
431 startup and reconfigure to service external acl lookups
432 of this type. (default 0)
434 Number of acl helper processes to keep ahead of traffic
435 loads. Squid will spawn this many at once whenever load
436 rises above the capabilities of existing processes.
437 Up to the value of children-max. (default 1)
438 concurrency=n concurrency level per process. Only used with helpers
439 capable of processing more than one query at a time.
440 cache=n limit the result cache size, default is unbounded.
441 grace=n Percentage remaining of TTL where a refresh of a
442 cached entry should be initiated without needing to
443 wait for a new reply. (default is for no grace period)
444 protocol=2.5 Compatibility mode for Squid-2.5 external acl helpers
445 ipv4 / ipv6 IP-mode used to communicate to this helper.
446 For compatability with older configurations and helpers
447 the default is 'ipv4'.
449 FORMAT specifications
451 %LOGIN Authenticated user login name
452 %EXT_USER Username from external acl
453 %IDENT Ident user name
455 %SRCPORT Client source port
458 %PROTO Requested protocol
460 %PATH Requested URL path
461 %METHOD Request method
462 %MYADDR Squid interface address
463 %MYPORT Squid http_port number
464 %PATH Requested URL-path (including query-string if any)
465 %USER_CERT SSL User certificate in PEM format
466 %USER_CERTCHAIN SSL User certificate chain in PEM format
467 %USER_CERT_xx SSL User certificate subject attribute xx
468 %USER_CA_xx SSL User certificate issuer attribute xx
470 %>{Header} HTTP request header "Header"
472 HTTP request header "Hdr" list member "member"
474 HTTP request header list member using ; as
475 list separator. ; can be any non-alphanumeric
478 %<{Header} HTTP reply header "Header"
480 HTTP reply header "Hdr" list member "member"
482 HTTP reply header list member using ; as
483 list separator. ; can be any non-alphanumeric
486 In addition to the above, any string specified in the referencing
487 acl will also be included in the helper request line, after the
488 specified formats (see the "acl external" directive)
490 The helper receives lines per the above format specification,
491 and returns lines starting with OK or ERR indicating the validity
492 of the request and optionally followed by additional keywords with
495 General result syntax:
497 OK/ERR keyword=value ...
501 user= The users name (login)
502 password= The users password (for login= cache_peer option)
503 message= Message describing the reason. Available as %o
505 tag= Apply a tag to a request (for both ERR and OK results)
506 Only sets a tag, does not alter existing tags.
507 log= String to be logged in access.log. Available as
508 %ea in logformat specifications
510 If protocol=3.0 (the default) then URL escaping is used to protect
511 each value in both requests and responses.
513 If using protocol=2.5 then all values need to be enclosed in quotes
514 if they may contain whitespace, or the whitespace escaped using \.
515 And quotes or \ characters within the keyword value must be \ escaped.
517 When using the concurrency= option the protocol is changed by
518 introducing a query channel tag infront of the request/response.
519 The query channel tag is a number between 0 and concurrency-1.
527 Defining an Access List
529 Every access list definition must begin with an aclname and acltype,
530 followed by either type-specific arguments or a quoted filename that
533 acl aclname acltype argument ...
534 acl aclname acltype "file" ...
536 When using "file", the file should contain one item per line.
538 By default, regular expressions are CASE-SENSITIVE. To make
539 them case-insensitive, use the -i option.
541 Some acl types require suspending the current request in order
542 to access some external data source.
543 Those which do are marked with the tag [slow], those which
544 don't are marked as [fast].
545 See http://wiki.squid-cache.org/SquidFaq/SquidAcl
546 for further information
548 ***** ACL TYPES AVAILABLE *****
550 acl aclname src ip-address/netmask ... # clients IP address [fast]
551 acl aclname src addr1-addr2/netmask ... # range of addresses [fast]
552 acl aclname dst ip-address/netmask ... # URL host's IP address [slow]
553 acl aclname myip ip-address/netmask ... # local socket IP address [fast]
555 acl aclname arp mac-address ... (xx:xx:xx:xx:xx:xx notation)
556 # The arp ACL requires the special configure option --enable-arp-acl.
557 # Furthermore, the ARP ACL code is not portable to all operating systems.
558 # It works on Linux, Solaris, Windows, FreeBSD, and some
559 # other *BSD variants.
562 # NOTE: Squid can only determine the MAC address for clients that are on
563 # the same subnet. If the client is on a different subnet,
564 # then Squid cannot find out its MAC address.
566 acl aclname srcdomain .foo.com ...
567 # reverse lookup, from client IP [slow]
568 acl aclname dstdomain .foo.com ...
569 # Destination server from URL [fast]
570 acl aclname srcdom_regex [-i] \.foo\.com ...
571 # regex matching client name [slow]
572 acl aclname dstdom_regex [-i] \.foo\.com ...
573 # regex matching server [fast]
575 # For dstdomain and dstdom_regex a reverse lookup is tried if a IP
576 # based URL is used and no match is found. The name "none" is used
577 # if the reverse lookup fails.
579 acl aclname src_as number ...
580 acl aclname dst_as number ...
582 # Except for access control, AS numbers can be used for
583 # routing of requests to specific caches. Here's an
584 # example for routing all requests for AS#1241 and only
585 # those to mycache.mydomain.net:
586 # acl asexample dst_as 1241
587 # cache_peer_access mycache.mydomain.net allow asexample
588 # cache_peer_access mycache_mydomain.net deny all
590 acl aclname peername myPeer ...
592 # match against a named cache_peer entry
593 # set unique name= on cache_peer lines for reliable use.
595 acl aclname time [day-abbrevs] [h1:m1-h2:m2]
605 # h1:m1 must be less than h2:m2
607 acl aclname url_regex [-i] ^http:// ...
608 # regex matching on whole URL [fast]
609 acl aclname urlpath_regex [-i] \.gif$ ...
610 # regex matching on URL path [fast]
612 acl aclname port 80 70 21 0-1024... # destination TCP port [fast]
614 acl aclname myport 3128 ... # local socket TCP port [fast]
615 acl aclname myportname 3128 ... # http(s)_port name [fast]
617 acl aclname proto HTTP FTP ... # request protocol [fast]
619 acl aclname method GET POST ... # HTTP request method [fast]
621 acl aclname http_status 200 301 500- 400-403 ...
622 # status code in reply [fast]
624 acl aclname browser [-i] regexp ...
625 # pattern match on User-Agent header (see also req_header below) [fast]
627 acl aclname referer_regex [-i] regexp ...
628 # pattern match on Referer header [fast]
629 # Referer is highly unreliable, so use with care
631 acl aclname ident username ...
632 acl aclname ident_regex [-i] pattern ...
633 # string match on ident output [slow]
634 # use REQUIRED to accept any non-null ident.
636 acl aclname proxy_auth [-i] username ...
637 acl aclname proxy_auth_regex [-i] pattern ...
638 # perform http authentication challenge to the client and match against
639 # supplied credentials [slow]
641 # takes a list of allowed usernames.
642 # use REQUIRED to accept any valid username.
644 # Will use proxy authentication in forward-proxy scenarios, and plain
645 # http authenticaiton in reverse-proxy scenarios
647 # NOTE: when a Proxy-Authentication header is sent but it is not
648 # needed during ACL checking the username is NOT logged
651 # NOTE: proxy_auth requires a EXTERNAL authentication program
652 # to check username/password combinations (see
653 # auth_param directive).
655 # NOTE: proxy_auth can't be used in a transparent/intercepting proxy
656 # as the browser needs to be configured for using a proxy in order
657 # to respond to proxy authentication.
659 acl aclname snmp_community string ...
660 # A community string to limit access to your SNMP Agent [fast]
663 # acl snmppublic snmp_community public
665 acl aclname maxconn number
666 # This will be matched when the client's IP address has
667 # more than <number> HTTP connections established. [fast]
669 acl aclname max_user_ip [-s] number
670 # This will be matched when the user attempts to log in from more
671 # than <number> different ip addresses. The authenticate_ip_ttl
672 # parameter controls the timeout on the ip entries. [fast]
673 # If -s is specified the limit is strict, denying browsing
674 # from any further IP addresses until the ttl has expired. Without
675 # -s Squid will just annoy the user by "randomly" denying requests.
676 # (the counter is reset each time the limit is reached and a
678 # NOTE: in acceleration mode or where there is mesh of child proxies,
679 # clients may appear to come from multiple addresses if they are
680 # going through proxy farms, so a limit of 1 may cause user problems.
682 acl aclname random probability
683 # Pseudo-randomly match requests. Based on the probability given.
684 # Probability may be written as a decimal (0.333), fraction (1/3)
685 # or ratio of matches:non-matches (3:5).
687 acl aclname req_mime_type [-i] mime-type ...
688 # regex match against the mime type of the request generated
689 # by the client. Can be used to detect file upload or some
690 # types HTTP tunneling requests [fast]
691 # NOTE: This does NOT match the reply. You cannot use this
692 # to match the returned file type.
694 acl aclname req_header header-name [-i] any\.regex\.here
695 # regex match against any of the known request headers. May be
696 # thought of as a superset of "browser", "referer" and "mime-type"
699 acl aclname rep_mime_type [-i] mime-type ...
700 # regex match against the mime type of the reply received by
701 # squid. Can be used to detect file download or some
702 # types HTTP tunneling requests. [fast]
703 # NOTE: This has no effect in http_access rules. It only has
704 # effect in rules that affect the reply data stream such as
707 acl aclname rep_header header-name [-i] any\.regex\.here
708 # regex match against any of the known reply headers. May be
709 # thought of as a superset of "browser", "referer" and "mime-type"
712 acl aclname external class_name [arguments...]
713 # external ACL lookup via a helper class defined by the
714 # external_acl_type directive [slow]
716 acl aclname user_cert attribute values...
717 # match against attributes in a user SSL certificate
718 # attribute is one of DN/C/O/CN/L/ST [fast]
720 acl aclname ca_cert attribute values...
721 # match against attributes a users issuing CA SSL certificate
722 # attribute is one of DN/C/O/CN/L/ST [fast]
724 acl aclname ext_user username ...
725 acl aclname ext_user_regex [-i] pattern ...
726 # string match on username returned by external acl helper [slow]
727 # use REQUIRED to accept any non-null user name.
729 acl aclname tag tagvalue ...
730 # string match on tag returned by external acl helper [slow]
732 acl aclname hier_code codename ...
733 # string match against squid hierarchy code(s); [fast]
734 # e.g., DIRECT, PARENT_HIT, NONE, etc.
736 # NOTE: This has no effect in http_access rules. It only has
737 # effect in rules that affect the reply data stream such as
741 acl macaddress arp 09:00:2b:23:45:67
742 acl myexample dst_as 1241
743 acl password proxy_auth REQUIRED
744 acl fileupload req_mime_type -i ^multipart/form-data$
745 acl javascript rep_mime_type -i ^application/x-javascript$
749 # Recommended minimum configuration:
751 acl manager proto cache_object
752 acl localhost src 127.0.0.1/32
753 @IPV6_ONLY_SETTING@acl localhost src ::1/128
754 acl to_localhost dst 127.0.0.0/8 0.0.0.0/32
755 @IPV6_ONLY_SETTING@acl to_localhost dst ::1/128
757 # Example rule allowing access from your local networks.
758 # Adapt to list your (internal) IP networks from where browsing
760 acl localnet src 10.0.0.0/8 # RFC1918 possible internal network
761 acl localnet src 172.16.0.0/12 # RFC1918 possible internal network
762 acl localnet src 192.168.0.0/16 # RFC1918 possible internal network
763 @IPV6_ONLY_SETTING@acl localnet src fc00::/7 # RFC 4193 local private network range
764 @IPV6_ONLY_SETTING@acl localnet src fe80::/10 # RFC 4291 link-local (directly plugged) machines
766 acl SSL_ports port 443
767 acl Safe_ports port 80 # http
768 acl Safe_ports port 21 # ftp
769 acl Safe_ports port 443 # https
770 acl Safe_ports port 70 # gopher
771 acl Safe_ports port 210 # wais
772 acl Safe_ports port 1025-65535 # unregistered ports
773 acl Safe_ports port 280 # http-mgmt
774 acl Safe_ports port 488 # gss-http
775 acl Safe_ports port 591 # filemaker
776 acl Safe_ports port 777 # multiling http
777 acl CONNECT method CONNECT
781 NAME: follow_x_forwarded_for
783 IFDEF: FOLLOW_X_FORWARDED_FOR
784 LOC: Config.accessList.followXFF
786 DEFAULT_IF_NONE: deny all
788 Allowing or Denying the X-Forwarded-For header to be followed to
789 find the original source of a request.
791 Requests may pass through a chain of several other proxies
792 before reaching us. The X-Forwarded-For header will contain a
793 comma-separated list of the IP addresses in the chain, with the
794 rightmost address being the most recent.
796 If a request reaches us from a source that is allowed by this
797 configuration item, then we consult the X-Forwarded-For header
798 to see where that host received the request from. If the
799 X-Forwarded-For header contains multiple addresses, and if
800 acl_uses_indirect_client is on, then we continue backtracking
801 until we reach an address for which we are not allowed to
802 follow the X-Forwarded-For header, or until we reach the first
803 address in the list. (If acl_uses_indirect_client is off, then
804 it's impossible to backtrack through more than one level of
805 X-Forwarded-For addresses.)
807 The end result of this process is an IP address that we will
808 refer to as the indirect client address. This address may
809 be treated as the client address for access control, ICAP, delay
810 pools and logging, depending on the acl_uses_indirect_client,
811 icap_uses_indirect_client, delay_pool_uses_indirect_client and
812 log_uses_indirect_client options.
814 This clause only supports fast acl types.
815 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
817 SECURITY CONSIDERATIONS:
819 Any host for which we follow the X-Forwarded-For header
820 can place incorrect information in the header, and Squid
821 will use the incorrect information as if it were the
822 source address of the request. This may enable remote
823 hosts to bypass any access control restrictions that are
824 based on the client's source addresses.
828 acl localhost src 127.0.0.1
829 acl my_other_proxy srcdomain .proxy.example.com
830 follow_x_forwarded_for allow localhost
831 follow_x_forwarded_for allow my_other_proxy
834 NAME: acl_uses_indirect_client
837 IFDEF: FOLLOW_X_FORWARDED_FOR
839 LOC: Config.onoff.acl_uses_indirect_client
841 Controls whether the indirect client address
842 (see follow_x_forwarded_for) is used instead of the
843 direct client address in acl matching.
846 NAME: delay_pool_uses_indirect_client
849 IFDEF: FOLLOW_X_FORWARDED_FOR&&DELAY_POOLS
851 LOC: Config.onoff.delay_pool_uses_indirect_client
853 Controls whether the indirect client address
854 (see follow_x_forwarded_for) is used instead of the
855 direct client address in delay pools.
858 NAME: log_uses_indirect_client
861 IFDEF: FOLLOW_X_FORWARDED_FOR
863 LOC: Config.onoff.log_uses_indirect_client
865 Controls whether the indirect client address
866 (see follow_x_forwarded_for) is used instead of the
867 direct client address in the access log.
872 LOC: Config.accessList.http
874 DEFAULT_IF_NONE: deny all
876 Allowing or Denying access based on defined access lists
878 Access to the HTTP port:
879 http_access allow|deny [!]aclname ...
881 NOTE on default values:
883 If there are no "access" lines present, the default is to deny
886 If none of the "access" lines cause a match, the default is the
887 opposite of the last line in the list. If the last line was
888 deny, the default is allow. Conversely, if the last line
889 is allow, the default will be deny. For these reasons, it is a
890 good idea to have an "deny all" entry at the end of your access
891 lists to avoid potential confusion.
893 This clause supports both fast and slow acl types.
894 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
899 # Recommended minimum Access Permission configuration:
901 # Only allow cachemgr access from localhost
902 http_access allow manager localhost
903 http_access deny manager
905 # Deny requests to certain unsafe ports
906 http_access deny !Safe_ports
908 # Deny CONNECT to other than secure SSL ports
909 http_access deny CONNECT !SSL_ports
911 # We strongly recommend the following be uncommented to protect innocent
912 # web applications running on the proxy server who think the only
913 # one who can access services on "localhost" is a local user
914 #http_access deny to_localhost
917 # INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS
920 # Example rule allowing access from your local networks.
921 # Adapt localnet in the ACL section to list your (internal) IP networks
922 # from where browsing should be allowed
923 http_access allow localnet
924 http_access allow localhost
926 # And finally deny all other access to this proxy
931 NAME: adapted_http_access http_access2
933 LOC: Config.accessList.adapted_http
936 Allowing or Denying access based on defined access lists
938 Essentially identical to http_access, but runs after redirectors
939 and ICAP/eCAP adaptation. Allowing access control based on their
942 If not set then only http_access is used.
945 NAME: http_reply_access
947 LOC: Config.accessList.reply
950 Allow replies to client requests. This is complementary to http_access.
952 http_reply_access allow|deny [!] aclname ...
954 NOTE: if there are no access lines present, the default is to allow
957 If none of the access lines cause a match the opposite of the
958 last line will apply. Thus it is good practice to end the rules
959 with an "allow all" or "deny all" entry.
961 This clause supports both fast and slow acl types.
962 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
967 LOC: Config.accessList.icp
969 DEFAULT_IF_NONE: deny all
971 Allowing or Denying access to the ICP port based on defined
974 icp_access allow|deny [!]aclname ...
976 See http_access for details
978 This clause only supports fast acl types.
979 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
981 # Allow ICP queries from local networks only
982 #icp_access allow localnet
989 LOC: Config.accessList.htcp
991 DEFAULT_IF_NONE: deny all
993 Allowing or Denying access to the HTCP port based on defined
996 htcp_access allow|deny [!]aclname ...
998 See http_access for details
1000 NOTE: The default if no htcp_access lines are present is to
1001 deny all traffic. This default may cause problems with peers
1002 using the htcp or htcp-oldsquid options.
1004 This clause only supports fast acl types.
1005 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1007 # Allow HTCP queries from local networks only
1008 #htcp_access allow localnet
1009 #htcp_access deny all
1012 NAME: htcp_clr_access
1015 LOC: Config.accessList.htcp_clr
1017 DEFAULT_IF_NONE: deny all
1019 Allowing or Denying access to purge content using HTCP based
1020 on defined access lists
1022 htcp_clr_access allow|deny [!]aclname ...
1024 See http_access for details
1026 This clause only supports fast acl types.
1027 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1029 # Allow HTCP CLR requests from trusted peers
1030 acl htcp_clr_peer src 172.16.1.2
1031 htcp_clr_access allow htcp_clr_peer
1036 LOC: Config.accessList.miss
1039 Use to force your neighbors to use you as a sibling instead of
1040 a parent. For example:
1042 acl localclients src 172.16.0.0/16
1043 miss_access allow localclients
1044 miss_access deny !localclients
1046 This means only your local clients are allowed to fetch
1047 MISSES and all other clients can only fetch HITS.
1049 By default, allow all clients who passed the http_access rules
1050 to fetch MISSES from us.
1052 This clause only supports fast acl types.
1053 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1056 NAME: ident_lookup_access
1060 DEFAULT_IF_NONE: deny all
1061 LOC: Ident::TheConfig.identLookup
1063 A list of ACL elements which, if matched, cause an ident
1064 (RFC 931) lookup to be performed for this request. For
1065 example, you might choose to always perform ident lookups
1066 for your main multi-user Unix boxes, but not for your Macs
1067 and PCs. By default, ident lookups are not performed for
1070 To enable ident lookups for specific client addresses, you
1071 can follow this example:
1073 acl ident_aware_hosts src 198.168.1.0/24
1074 ident_lookup_access allow ident_aware_hosts
1075 ident_lookup_access deny all
1077 Only src type ACL checks are fully supported. A srcdomain
1078 ACL might work at times, but it will not always provide
1081 This clause only supports fast acl types.
1082 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1085 NAME: reply_body_max_size
1086 COMMENT: size [acl acl...]
1089 LOC: Config.ReplyBodySize
1091 This option specifies the maximum size of a reply body. It can be
1092 used to prevent users from downloading very large files, such as
1093 MP3's and movies. When the reply headers are received, the
1094 reply_body_max_size lines are processed, and the first line where
1095 all (if any) listed ACLs are true is used as the maximum body size
1098 This size is checked twice. First when we get the reply headers,
1099 we check the content-length value. If the content length value exists
1100 and is larger than the allowed size, the request is denied and the
1101 user receives an error message that says "the request or reply
1102 is too large." If there is no content-length, and the reply
1103 size exceeds this limit, the client's connection is just closed
1104 and they will receive a partial reply.
1106 WARNING: downstream caches probably can not detect a partial reply
1107 if there is no content-length header, so they will cache
1108 partial responses and give them out as hits. You should NOT
1109 use this option if you have downstream caches.
1111 WARNING: A maximum size smaller than the size of squid's error messages
1112 will cause an infinite loop and crash squid. Ensure that the smallest
1113 non-zero value you use is greater that the maximum header size plus
1114 the size of your largest error page.
1116 If you set this parameter none (the default), there will be
1119 Configuration Format is:
1120 reply_body_max_size SIZE UNITS [acl ...]
1122 reply_body_max_size 10 MB
1128 -----------------------------------------------------------------------------
1131 NAME: http_port ascii_port
1132 TYPE: http_port_list
1134 LOC: Config.Sockaddr.http
1136 Usage: port [options]
1137 hostname:port [options]
1138 1.2.3.4:port [options]
1140 The socket addresses where Squid will listen for HTTP client
1141 requests. You may specify multiple socket addresses.
1142 There are three forms: port alone, hostname with port, and
1143 IP address with port. If you specify a hostname or IP
1144 address, Squid binds the socket to that specific
1145 address. This replaces the old 'tcp_incoming_address'
1146 option. Most likely, you do not need to bind to a specific
1147 address, so you can use the port number alone.
1149 If you are running Squid in accelerator mode, you
1150 probably want to listen on port 80 also, or instead.
1152 The -a command line option may be used to specify additional
1153 port(s) where Squid listens for proxy request. Such ports will
1154 be plain proxy ports with no options.
1156 You may specify multiple socket addresses on multiple lines.
1160 intercept Support for IP-Layer interception of
1161 outgoing requests without browser settings.
1162 NP: disables authentication and IPv6 on the port.
1164 tproxy Support Linux TPROXY for spoofing outgoing
1165 connections using the client IP address.
1166 NP: disables authentication and maybe IPv6 on the port.
1168 accel Accelerator mode. Also needs at least one of
1169 vhost / vport / defaultsite.
1171 allow-direct Allow direct forwarding in accelerator mode. Normally
1172 accelerated requests are denied direct forwarding as if
1173 never_direct was used.
1175 defaultsite=domainname
1176 What to use for the Host: header if it is not present
1177 in a request. Determines what site (not origin server)
1178 accelerators should consider the default.
1181 vhost Accelerator mode using Host header for virtual
1182 domain support. Implies accel.
1184 vport Accelerator with IP based virtual host support.
1187 vport=NN As above, but uses specified port number rather
1188 than the http_port number. Implies accel.
1190 protocol= Protocol to reconstruct accelerated requests with.
1193 ignore-cc Ignore request Cache-Control headers.
1195 Warning: This option violates HTTP specifications if
1196 used in non-accelerator setups.
1198 connection-auth[=on|off]
1199 use connection-auth=off to tell Squid to prevent
1200 forwarding Microsoft connection oriented authentication
1201 (NTLM, Negotiate and Kerberos)
1203 disable-pmtu-discovery=
1204 Control Path-MTU discovery usage:
1205 off lets OS decide on what to do (default).
1206 transparent disable PMTU discovery when transparent
1208 always disable always PMTU discovery.
1210 In many setups of transparently intercepting proxies
1211 Path-MTU discovery can not work on traffic towards the
1212 clients. This is the case when the intercepting device
1213 does not fully track connections and fails to forward
1214 ICMP must fragment messages to the cache server. If you
1215 have such setup and experience that certain clients
1216 sporadically hang or never complete requests set
1217 disable-pmtu-discovery option to 'transparent'.
1219 sslBump Intercept each CONNECT request matching ssl_bump ACL,
1220 establish secure connection with the client and with
1221 the server, decrypt HTTP messages as they pass through
1222 Squid, and treat them as unencrypted HTTP messages,
1223 becoming the man-in-the-middle.
1225 When this option is enabled, additional options become
1226 available to specify SSL-related properties of the
1227 client-side connection: cert, key, version, cipher,
1228 options, clientca, cafile, capath, crlfile, dhparams,
1229 sslflags, and sslcontext. See the https_port directive
1230 for more information on these options.
1232 The ssl_bump option is required to fully enable
1233 the SslBump feature.
1235 name= Specifies a internal name for the port. Defaults to
1236 the port specification (port or addr:port)
1238 tcpkeepalive[=idle,interval,timeout]
1239 Enable TCP keepalive probes of idle connections
1240 idle is the initial time before TCP starts probing
1241 the connection, interval how often to probe, and
1242 timeout the time before giving up.
1244 If you run Squid on a dual-homed machine with an internal
1245 and an external interface we recommend you to specify the
1246 internal address:port in http_port. This way Squid will only be
1247 visible on the internal address.
1251 # Squid normally listens to port 3128
1252 http_port @DEFAULT_HTTP_PORT@
1258 TYPE: https_port_list
1260 LOC: Config.Sockaddr.https
1262 Usage: [ip:]port cert=certificate.pem [key=key.pem] [options...]
1264 The socket address where Squid will listen for HTTPS client
1267 This is really only useful for situations where you are running
1268 squid in accelerator mode and you want to do the SSL work at the
1271 You may specify multiple socket addresses on multiple lines,
1272 each with their own SSL certificate and/or options.
1276 accel Accelerator mode. Also needs at least one of
1277 defaultsite or vhost.
1279 defaultsite= The name of the https site presented on
1280 this port. Implies accel.
1282 vhost Accelerator mode using Host header for virtual
1283 domain support. Requires a wildcard certificate
1284 or other certificate valid for more than one domain.
1287 protocol= Protocol to reconstruct accelerated requests with.
1290 cert= Path to SSL certificate (PEM format).
1292 key= Path to SSL private key file (PEM format)
1293 if not specified, the certificate file is
1294 assumed to be a combined certificate and
1297 version= The version of SSL/TLS supported
1298 1 automatic (default)
1303 cipher= Colon separated list of supported ciphers.
1305 options= Various SSL engine options. The most important
1307 NO_SSLv2 Disallow the use of SSLv2
1308 NO_SSLv3 Disallow the use of SSLv3
1309 NO_TLSv1 Disallow the use of TLSv1
1310 SINGLE_DH_USE Always create a new key when using
1311 temporary/ephemeral DH key exchanges
1312 See src/ssl_support.c or OpenSSL SSL_CTX_set_options
1313 documentation for a complete list of options.
1315 clientca= File containing the list of CAs to use when
1316 requesting a client certificate.
1318 cafile= File containing additional CA certificates to
1319 use when verifying client certificates. If unset
1320 clientca will be used.
1322 capath= Directory containing additional CA certificates
1323 and CRL lists to use when verifying client certificates.
1325 crlfile= File of additional CRL lists to use when verifying
1326 the client certificate, in addition to CRLs stored in
1327 the capath. Implies VERIFY_CRL flag below.
1329 dhparams= File containing DH parameters for temporary/ephemeral
1332 sslflags= Various flags modifying the use of SSL:
1334 Don't request client certificates
1335 immediately, but wait until acl processing
1336 requires a certificate (not yet implemented).
1338 Don't use the default CA lists built in
1341 Don't allow for session reuse. Each connection
1342 will result in a new SSL session.
1344 Verify CRL lists when accepting client
1347 Verify CRL lists for all certificates in the
1348 client certificate chain.
1350 sslcontext= SSL session ID context identifier.
1352 vport Accelerator with IP based virtual host support.
1354 vport=NN As above, but uses specified port number rather
1355 than the https_port number. Implies accel.
1357 name= Specifies a internal name for the port. Defaults to
1358 the port specification (port or addr:port)
1362 NAME: tcp_outgoing_tos tcp_outgoing_ds tcp_outgoing_dscp
1365 LOC: Config.accessList.outgoing_tos
1367 Allows you to select a TOS/Diffserv value to mark outgoing
1368 connections with, based on the username or source address
1371 tcp_outgoing_tos ds-field [!]aclname ...
1373 Example where normal_service_net uses the TOS value 0x00
1374 and good_service_net uses 0x20
1376 acl normal_service_net src 10.0.0.0/255.255.255.0
1377 acl good_service_net src 10.0.1.0/255.255.255.0
1378 tcp_outgoing_tos 0x00 normal_service_net
1379 tcp_outgoing_tos 0x20 good_service_net
1381 TOS/DSCP values really only have local significance - so you should
1382 know what you're specifying. For more information, see RFC2474,
1383 RFC2475, and RFC3260.
1385 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
1386 "default" to use whatever default your host has. Note that in
1387 practice often only values 0 - 63 is usable as the two highest bits
1388 have been redefined for use by ECN (RFC3168).
1390 Processing proceeds in the order specified, and stops at first fully
1393 Note: The use of this directive using client dependent ACLs is
1394 incompatible with the use of server side persistent connections. To
1395 ensure correct results it is best to set server_persisten_connections
1396 to off when using this directive in such configurations.
1399 NAME: clientside_tos
1402 LOC: Config.accessList.clientside_tos
1404 Allows you to select a TOS/Diffserv value to mark client-side
1405 connections with, based on the username or source address
1415 Allows you to select a TOS/DSCP value to mark outgoing
1416 connections with, based on where the reply was sourced.
1418 TOS values really only have local significance - so you should
1419 know what you're specifying. For more information, see RFC2474,
1420 RFC2475, and RFC3260.
1422 The TOS/DSCP byte must be exactly that - octet value 0x00-0xFF.
1423 Note that in practice often only values up to 0x3F are usable
1424 as the two highest bits have been redefined for use by ECN
1427 This setting is configured by setting the source TOS values:
1429 local-hit=0xFF Value to mark local cache hits.
1431 sibling-hit=0xFF Value to mark hits from sibling peers.
1433 parent-hit=0xFF Value to mark hits from parent peers.
1436 NOTE: 'miss' preserve feature is only possible on Linux at this time.
1438 For the following to work correctly, you will need to patch your
1439 linux kernel with the TOS preserving ZPH patch.
1440 The kernel patch can be downloaded from http://zph.bratcheda.org
1442 disable-preserve-miss
1443 If set, any HTTP response towards clients will
1444 have the TOS value of the response comming from the
1445 remote server masked with the value of miss-mask.
1448 Allows you to mask certain bits in the TOS received from the
1449 remote server, before copying the value to the TOS sent
1451 Default: 0xFF (TOS from server is not changed).
1455 NAME: tcp_outgoing_address
1458 LOC: Config.accessList.outgoing_address
1460 Allows you to map requests to different outgoing IP addresses
1461 based on the username or source address of the user making
1464 tcp_outgoing_address ipaddr [[!]aclname] ...
1466 Example where requests from 10.0.0.0/24 will be forwarded
1467 with source address 10.1.0.1, 10.0.2.0/24 forwarded with
1468 source address 10.1.0.2 and the rest will be forwarded with
1469 source address 10.1.0.3.
1471 acl normal_service_net src 10.0.0.0/24
1472 acl good_service_net src 10.0.2.0/24
1473 tcp_outgoing_address 10.1.0.1 normal_service_net
1474 tcp_outgoing_address 10.1.0.2 good_service_net
1475 tcp_outgoing_address 10.1.0.3
1477 Processing proceeds in the order specified, and stops at first fully
1480 Note: The use of this directive using client dependent ACLs is
1481 incompatible with the use of server side persistent connections. To
1482 ensure correct results it is best to set server_persistent_connections
1483 to off when using this directive in such configurations.
1485 Note: The use of this directive to set a local IP on outgoing TCP links
1486 is incompatible with using TPROXY to set client IP out outbound TCP links.
1487 When needing to contact peers use the no-tproxy cache_peer option to
1488 re-enable normal forwarding such as this.
1492 Squid is built with a capability of bridging the IPv4 and IPv6
1494 tcp_outgoing_address as exampled above breaks this bridging by forcing
1495 all outbound traffic through a certain IPv4 which may be on the wrong
1496 side of the IPv4/IPv6 boundary.
1498 To operate with tcp_outgoing_address and keep the bridging benefits
1499 an additional ACL needs to be used which ensures the IPv6-bound traffic
1500 is never forced or permitted out the IPv4 interface.
1502 acl to_ipv6 dst ipv6
1503 tcp_outgoing_address 2002::c001 good_service_net to_ipv6
1504 tcp_outgoing_address 10.1.0.2 good_service_net !to_ipv6
1506 tcp_outgoing_address 2002::beef normal_service_net to_ipv6
1507 tcp_outgoing_address 10.1.0.1 normal_service_net !to_ipv6
1509 tcp_outgoing_address 2002::1 to_ipv6
1510 tcp_outgoing_address 10.1.0.3 !to_ipv6
1513 'dst ipv6' bases its selection assuming DIRECT access.
1514 If peers are used the peername ACL are needed to select outgoing
1515 address which can link to the peer.
1517 'dst ipv6' is a slow ACL. It will only work here if 'dst' is used
1518 previously in the http_access rules to locate the destination IP.
1519 Some more magic may be needed for that:
1520 http_access allow to_ipv6 !all
1521 (meaning, allow if to IPv6 but not from anywhere ;)
1527 -----------------------------------------------------------------------------
1530 NAME: ssl_unclean_shutdown
1534 LOC: Config.SSL.unclean_shutdown
1536 Some browsers (especially MSIE) bugs out on SSL shutdown
1543 LOC: Config.SSL.ssl_engine
1546 The OpenSSL engine to use. You will need to set this if you
1547 would like to use hardware SSL acceleration for example.
1550 NAME: sslproxy_client_certificate
1553 LOC: Config.ssl_client.cert
1556 Client SSL Certificate to use when proxying https:// URLs
1559 NAME: sslproxy_client_key
1562 LOC: Config.ssl_client.key
1565 Client SSL Key to use when proxying https:// URLs
1568 NAME: sslproxy_version
1571 LOC: Config.ssl_client.version
1574 SSL version level to use when proxying https:// URLs
1577 NAME: sslproxy_options
1580 LOC: Config.ssl_client.options
1583 SSL engine options to use when proxying https:// URLs
1585 The most important being:
1587 NO_SSLv2 Disallow the use of SSLv2
1588 NO_SSLv3 Disallow the use of SSLv3
1589 NO_TLSv1 Disallow the use of TLSv1
1591 Always create a new key when using
1592 temporary/ephemeral DH key exchanges
1594 These options vary depending on your SSL engine.
1595 See the OpenSSL SSL_CTX_set_options documentation for a
1596 complete list of possible options.
1599 NAME: sslproxy_cipher
1602 LOC: Config.ssl_client.cipher
1605 SSL cipher list to use when proxying https:// URLs
1607 Colon separated list of supported ciphers.
1610 NAME: sslproxy_cafile
1613 LOC: Config.ssl_client.cafile
1616 file containing CA certificates to use when verifying server
1617 certificates while proxying https:// URLs
1620 NAME: sslproxy_capath
1623 LOC: Config.ssl_client.capath
1626 directory containing CA certificates to use when verifying
1627 server certificates while proxying https:// URLs
1633 LOC: Config.accessList.ssl_bump
1636 This ACL controls which CONNECT requests to an http_port
1637 marked with an sslBump flag are actually "bumped". Please
1638 see the sslBump flag of an http_port option for more details
1639 about decoding proxied SSL connections.
1641 By default, no requests are bumped.
1643 See also: http_port sslBump
1645 This clause only supports fast acl types.
1646 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1649 # Example: Bump all requests except those originating from localhost and
1650 # those going to webax.com or example.com sites.
1652 acl localhost src 127.0.0.1/32
1653 acl broken_sites dstdomain .webax.com
1654 acl broken_sites dstdomain .example.com
1655 ssl_bump deny localhost
1656 ssl_bump deny broken_sites
1660 NAME: sslproxy_flags
1663 LOC: Config.ssl_client.flags
1666 Various flags modifying the use of SSL while proxying https:// URLs:
1667 DONT_VERIFY_PEER Accept certificates that fail verification.
1668 For refined control, see sslproxy_cert_error.
1669 NO_DEFAULT_CA Don't use the default CA list built in
1674 NAME: sslproxy_cert_error
1677 LOC: Config.ssl_client.cert_error
1680 Use this ACL to bypass server certificate validation errors.
1682 For example, the following lines will bypass all validation errors
1683 when talking to servers located at 172.16.0.0/16. All other
1684 validation errors will result in ERR_SECURE_CONNECT_FAIL error.
1686 acl BrokenServersAtTrustedIP dst 172.16.0.0/16
1687 sslproxy_cert_error allow BrokenServersAtTrustedIP
1688 sslproxy_cert_error deny all
1690 This clause only supports fast acl types.
1691 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
1692 Using slow acl types may result in server crashes
1694 Without this option, all server certificate validation errors
1695 terminate the transaction. Bypassing validation errors is dangerous
1696 because an error usually implies that the server cannot be trusted and
1697 the connection may be insecure.
1699 See also: sslproxy_flags and DONT_VERIFY_PEER.
1701 Default setting: sslproxy_cert_error deny all
1706 NAME: sslpassword_program
1709 LOC: Config.Program.ssl_password
1712 Specify a program used for entering SSL key passphrases
1713 when using encrypted SSL certificate keys. If not specified
1714 keys must either be unencrypted, or Squid started with the -N
1715 option to allow it to query interactively for the passphrase.
1719 OPTIONS WHICH AFFECT THE NEIGHBOR SELECTION ALGORITHM
1720 -----------------------------------------------------------------------------
1728 To specify other caches in a hierarchy, use the format:
1730 cache_peer hostname type http-port icp-port [options]
1735 # hostname type port port options
1736 # -------------------- -------- ----- ----- -----------
1737 cache_peer parent.foo.net parent 3128 3130 default
1738 cache_peer sib1.foo.net sibling 3128 3130 proxy-only
1739 cache_peer sib2.foo.net sibling 3128 3130 proxy-only
1740 cache_peer example.com parent 80 0 no-query default
1741 cache_peer cdn.example.com sibling 3128 0
1743 type: either 'parent', 'sibling', or 'multicast'.
1745 proxy-port: The port number where the peer accept HTTP requests.
1746 For other Squid proxies this is usually 3128
1747 For web servers this is usually 80
1749 icp-port: Used for querying neighbor caches about objects.
1750 Set to 0 if the peer does not support ICP or HTCP.
1751 See ICP and HTCP options below for additional details.
1754 ==== ICP OPTIONS ====
1756 You MUST also set icp_port and icp_access explicitly when using these options.
1757 The defaults will prevent peer traffic using ICP.
1760 no-query Disable ICP queries to this neighbor.
1763 Indicates the named peer is a member of a multicast group.
1764 ICP queries will not be sent directly to the peer, but ICP
1765 replies will be accepted from it.
1767 closest-only Indicates that, for ICP_OP_MISS replies, we'll only forward
1768 CLOSEST_PARENT_MISSes and never FIRST_PARENT_MISSes.
1771 To only send ICP queries to this neighbor infrequently.
1772 This is used to keep the neighbor round trip time updated
1773 and is usually used in conjunction with weighted-round-robin.
1776 ==== HTCP OPTIONS ====
1778 You MUST also set htcp_port and htcp_access explicitly when using these options.
1779 The defaults will prevent peer traffic using HTCP.
1782 htcp Send HTCP, instead of ICP, queries to the neighbor.
1783 You probably also want to set the "icp-port" to 4827
1786 htcp-oldsquid Send HTCP to old Squid versions.
1788 htcp-no-clr Send HTCP to the neighbor but without
1789 sending any CLR requests. This cannot be used with
1792 htcp-only-clr Send HTCP to the neighbor but ONLY CLR requests.
1793 This cannot be used with htcp-no-clr.
1796 Send HTCP to the neighbor including CLRs but only when
1797 they do not result from PURGE requests.
1800 Forward any HTCP CLR requests this proxy receives to the peer.
1803 ==== PEER SELECTION METHODS ====
1805 The default peer selection method is ICP, with the first responding peer
1806 being used as source. These options can be used for better load balancing.
1809 default This is a parent cache which can be used as a "last-resort"
1810 if a peer cannot be located by any of the peer-selection methods.
1811 If specified more than once, only the first is used.
1813 round-robin Load-Balance parents which should be used in a round-robin
1814 fashion in the absence of any ICP queries.
1815 weight=N can be used to add bias.
1817 weighted-round-robin
1818 Load-Balance parents which should be used in a round-robin
1819 fashion with the frequency of each parent being based on the
1820 round trip time. Closer parents are used more often.
1821 Usually used for background-ping parents.
1822 weight=N can be used to add bias.
1824 carp Load-Balance parents which should be used as a CARP array.
1825 The requests will be distributed among the parents based on the
1826 CARP load balancing hash function based on their weight.
1828 userhash Load-balance parents based on the client proxy_auth or ident username.
1830 sourcehash Load-balance parents based on the client source IP.
1833 To be used only for cache peers of type "multicast".
1834 ALL members of this multicast group have "sibling"
1835 relationship with it, not "parent". This is to a mulicast
1836 group when the requested object would be fetched only from
1837 a "parent" cache, anyway. It's useful, e.g., when
1838 configuring a pool of redundant Squid proxies, being
1839 members of the same multicast group.
1842 ==== PEER SELECTION OPTIONS ====
1844 weight=N use to affect the selection of a peer during any weighted
1845 peer-selection mechanisms.
1846 The weight must be an integer; default is 1,
1847 larger weights are favored more.
1848 This option does not affect parent selection if a peering
1849 protocol is not in use.
1851 basetime=N Specify a base amount to be subtracted from round trip
1853 It is subtracted before division by weight in calculating
1854 which parent to fectch from. If the rtt is less than the
1855 base time the rtt is set to a minimal value.
1857 ttl=N Specify a IP multicast TTL to use when sending an ICP
1858 queries to this address.
1859 Only useful when sending to a multicast group.
1860 Because we don't accept ICP replies from random
1861 hosts, you must configure other group members as
1862 peers with the 'multicast-responder' option.
1864 no-delay To prevent access to this neighbor from influencing the
1867 digest-url=URL Tell Squid to fetch the cache digest (if digests are
1868 enabled) for this host from the specified URL rather
1869 than the Squid default location.
1872 ==== ACCELERATOR / REVERSE-PROXY OPTIONS ====
1874 originserver Causes this parent to be contacted as an origin server.
1875 Meant to be used in accelerator setups when the peer
1879 Set the Host header of requests forwarded to this peer.
1880 Useful in accelerator setups where the server (peer)
1881 expects a certain domain name but clients may request
1882 others. ie example.com or www.example.com
1884 no-digest Disable request of cache digests.
1887 Disables requesting ICMP RTT database (NetDB).
1890 ==== AUTHENTICATION OPTIONS ====
1893 If this is a personal/workgroup proxy and your parent
1894 requires proxy authentication.
1896 Note: The string can include URL escapes (i.e. %20 for
1897 spaces). This also means % must be written as %%.
1900 Send login details received from client to this peer.
1901 Both Proxy- and WWW-Authorization headers are passed
1902 without alteration to the peer.
1903 Authentication is not required by Squid for this to work.
1905 Note: This will pass any form of authentication but
1906 only Basic auth will work through a proxy unless the
1907 connection-auth options are also used.
1909 login=PASS Send login details received from client to this peer.
1910 Authentication is not required by this option.
1912 If there are no client-provided authentication headers
1913 to pass on, but username and password are available
1914 from an external ACL user= and password= result tags
1915 they may be sent instead.
1917 Note: To combine this with proxy_auth both proxies must
1918 share the same user database as HTTP only allows for
1919 a single login (one for proxy, one for origin server).
1920 Also be warned this will expose your users proxy
1921 password to the peer. USE WITH CAUTION
1924 Send the username to the upstream cache, but with a
1925 fixed password. This is meant to be used when the peer
1926 is in another administrative domain, but it is still
1927 needed to identify each user.
1928 The star can optionally be followed by some extra
1929 information which is added to the username. This can
1930 be used to identify this proxy to the peer, similar to
1931 the login=username:password option above.
1934 If this is a personal/workgroup proxy and your parent
1935 requires a secure proxy authentication.
1936 The first principal from the default keytab or defined by
1937 the environment variable KRB5_KTNAME will be used.
1939 login=NEGOTIATE:principal_name
1940 If this is a personal/workgroup proxy and your parent
1941 requires a secure proxy authentication.
1942 The principal principal_name from the default keytab or
1943 defined by the environment variable KRB5_KTNAME will be
1946 connection-auth=on|off
1947 Tell Squid that this peer does or not support Microsoft
1948 connection oriented authentication, and any such
1949 challenges received from there should be ignored.
1950 Default is auto to automatically determine the status
1954 ==== SSL / HTTPS / TLS OPTIONS ====
1956 ssl Encrypt connections to this peer with SSL/TLS.
1958 sslcert=/path/to/ssl/certificate
1959 A client SSL certificate to use when connecting to
1962 sslkey=/path/to/ssl/key
1963 The private SSL key corresponding to sslcert above.
1964 If 'sslkey' is not specified 'sslcert' is assumed to
1965 reference a combined file containing both the
1966 certificate and the key.
1969 The SSL version to use when connecting to this peer
1970 1 = automatic (default)
1975 sslcipher=... The list of valid SSL ciphers to use when connecting
1978 ssloptions=... Specify various SSL engine options:
1979 NO_SSLv2 Disallow the use of SSLv2
1980 NO_SSLv3 Disallow the use of SSLv3
1981 NO_TLSv1 Disallow the use of TLSv1
1982 See src/ssl_support.c or the OpenSSL documentation for
1983 a more complete list.
1985 sslcafile=... A file containing additional CA certificates to use
1986 when verifying the peer certificate.
1988 sslcapath=... A directory containing additional CA certificates to
1989 use when verifying the peer certificate.
1991 sslcrlfile=... A certificate revocation list file to use when
1992 verifying the peer certificate.
1994 sslflags=... Specify various flags modifying the SSL implementation:
1997 Accept certificates even if they fail to
2000 Don't use the default CA list built in
2003 Don't verify the peer certificate
2004 matches the server name
2006 ssldomain= The peer name as advertised in it's certificate.
2007 Used for verifying the correctness of the received peer
2008 certificate. If not specified the peer hostname will be
2012 Enable the "Front-End-Https: On" header needed when
2013 using Squid as a SSL frontend in front of Microsoft OWA.
2014 See MS KB document Q307347 for details on this header.
2015 If set to auto the header will only be added if the
2016 request is forwarded as a https:// URL.
2019 ==== GENERAL OPTIONS ====
2022 A peer-specific connect timeout.
2023 Also see the peer_connect_timeout directive.
2025 connect-fail-limit=N
2026 How many times connecting to a peer must fail before
2027 it is marked as down. Default is 10.
2029 allow-miss Disable Squid's use of only-if-cached when forwarding
2030 requests to siblings. This is primarily useful when
2031 icp_hit_stale is used by the sibling. To extensive use
2032 of this option may result in forwarding loops, and you
2033 should avoid having two-way peerings with this option.
2034 For example to deny peer usage on requests from peer
2035 by denying cache_peer_access if the source is a peer.
2037 max-conn=N Limit the amount of connections Squid may open to this
2040 name=xxx Unique name for the peer.
2041 Required if you have multiple peers on the same host
2042 but different ports.
2043 This name can be used in cache_peer_access and similar
2044 directives to dentify the peer.
2045 Can be used by outgoing access controls through the
2048 no-tproxy Do not use the client-spoof TPROXY support when forwarding
2049 requests to this peer. Use normal address selection instead.
2051 proxy-only objects fetched from the peer will not be stored locally.
2055 NAME: cache_peer_domain cache_host_domain
2060 Use to limit the domains for which a neighbor cache will be
2063 cache_peer_domain cache-host domain [domain ...]
2064 cache_peer_domain cache-host !domain
2066 For example, specifying
2068 cache_peer_domain parent.foo.net .edu
2070 has the effect such that UDP query packets are sent to
2071 'bigserver' only when the requested object exists on a
2072 server in the .edu domain. Prefixing the domainname
2073 with '!' means the cache will be queried for objects
2076 NOTE: * Any number of domains may be given for a cache-host,
2077 either on the same or separate lines.
2078 * When multiple domains are given for a particular
2079 cache-host, the first matched domain is applied.
2080 * Cache hosts with no domain restrictions are queried
2082 * There are no defaults.
2083 * There is also a 'cache_peer_access' tag in the ACL
2087 NAME: cache_peer_access
2092 Similar to 'cache_peer_domain' but provides more flexibility by
2095 cache_peer_access cache-host allow|deny [!]aclname ...
2097 The syntax is identical to 'http_access' and the other lists of
2098 ACL elements. See the comments for 'http_access' below, or
2099 the Squid FAQ (http://wiki.squid-cache.org/SquidFaq/SquidAcl).
2102 NAME: neighbor_type_domain
2103 TYPE: hostdomaintype
2107 usage: neighbor_type_domain neighbor parent|sibling domain domain ...
2109 Modifying the neighbor type for specific domains is now
2110 possible. You can treat some domains differently than the
2111 default neighbor type specified on the 'cache_peer' line.
2112 Normally it should only be necessary to list domains which
2113 should be treated differently because the default neighbor type
2114 applies for hostnames which do not match domains listed here.
2117 cache_peer cache.foo.org parent 3128 3130
2118 neighbor_type_domain cache.foo.org sibling .com .net
2119 neighbor_type_domain cache.foo.org sibling .au .de
2122 NAME: dead_peer_timeout
2126 LOC: Config.Timeout.deadPeer
2128 This controls how long Squid waits to declare a peer cache
2129 as "dead." If there are no ICP replies received in this
2130 amount of time, Squid will declare the peer dead and not
2131 expect to receive any further ICP replies. However, it
2132 continues to send ICP queries, and will mark the peer as
2133 alive upon receipt of the first subsequent ICP reply.
2135 This timeout also affects when Squid expects to receive ICP
2136 replies from peers. If more than 'dead_peer' seconds have
2137 passed since the last ICP reply was received, Squid will not
2138 expect to receive an ICP reply on the next query. Thus, if
2139 your time between requests is greater than this timeout, you
2140 will see a lot of requests sent DIRECT to origin servers
2141 instead of to your parents.
2144 NAME: forward_max_tries
2147 LOC: Config.forward_max_tries
2149 Controls how many different forward paths Squid will try
2150 before giving up. See also forward_timeout.
2153 NAME: hierarchy_stoplist
2156 LOC: Config.hierarchy_stoplist
2158 A list of words which, if found in a URL, cause the object to
2159 be handled directly by this cache. In other words, use this
2160 to not query neighbor caches for certain objects. You may
2161 list this option multiple times.
2162 Note: never_direct overrides this option.
2165 # We recommend you to use at least the following line.
2166 hierarchy_stoplist cgi-bin ?
2171 MEMORY CACHE OPTIONS
2172 -----------------------------------------------------------------------------
2179 LOC: Config.memMaxSize
2181 NOTE: THIS PARAMETER DOES NOT SPECIFY THE MAXIMUM PROCESS SIZE.
2182 IT ONLY PLACES A LIMIT ON HOW MUCH ADDITIONAL MEMORY SQUID WILL
2183 USE AS A MEMORY CACHE OF OBJECTS. SQUID USES MEMORY FOR OTHER
2184 THINGS AS WELL. SEE THE SQUID FAQ SECTION 8 FOR DETAILS.
2186 'cache_mem' specifies the ideal amount of memory to be used
2188 * In-Transit objects
2190 * Negative-Cached objects
2192 Data for these objects are stored in 4 KB blocks. This
2193 parameter specifies the ideal upper limit on the total size of
2194 4 KB blocks allocated. In-Transit objects take the highest
2197 In-transit objects have priority over the others. When
2198 additional space is needed for incoming data, negative-cached
2199 and hot objects will be released. In other words, the
2200 negative-cached and hot objects will fill up any unused space
2201 not needed for in-transit objects.
2203 If circumstances require, this limit will be exceeded.
2204 Specifically, if your incoming request rate requires more than
2205 'cache_mem' of memory to hold in-transit objects, Squid will
2206 exceed this limit to satisfy the new requests. When the load
2207 decreases, blocks will be freed until the high-water mark is
2208 reached. Thereafter, blocks will be used to store hot
2212 NAME: maximum_object_size_in_memory
2216 LOC: Config.Store.maxInMemObjSize
2218 Objects greater than this size will not be attempted to kept in
2219 the memory cache. This should be set high enough to keep objects
2220 accessed frequently in memory to improve performance whilst low
2221 enough to keep larger objects from hoarding cache_mem.
2224 NAME: memory_cache_mode
2229 Controls which objects to keep in the memory cache (cache_mem)
2231 always Keep most recently fetched objects in memory (default)
2233 disk Only disk cache hits are kept in memory, which means
2234 an object must first be cached on disk and then hit
2235 a second time before cached in memory.
2237 network Only objects fetched from network is kept in memory
2240 NAME: memory_replacement_policy
2242 LOC: Config.memPolicy
2245 The memory replacement policy parameter determines which
2246 objects are purged from memory when memory space is needed.
2248 See cache_replacement_policy for details.
2253 -----------------------------------------------------------------------------
2256 NAME: cache_replacement_policy
2258 LOC: Config.replPolicy
2261 The cache replacement policy parameter determines which
2262 objects are evicted (replaced) when disk space is needed.
2264 lru : Squid's original list based LRU policy
2265 heap GDSF : Greedy-Dual Size Frequency
2266 heap LFUDA: Least Frequently Used with Dynamic Aging
2267 heap LRU : LRU policy implemented using a heap
2269 Applies to any cache_dir lines listed below this.
2271 The LRU policies keeps recently referenced objects.
2273 The heap GDSF policy optimizes object hit rate by keeping smaller
2274 popular objects in cache so it has a better chance of getting a
2275 hit. It achieves a lower byte hit rate than LFUDA though since
2276 it evicts larger (possibly popular) objects.
2278 The heap LFUDA policy keeps popular objects in cache regardless of
2279 their size and thus optimizes byte hit rate at the expense of
2280 hit rate since one large, popular object will prevent many
2281 smaller, slightly less popular objects from being cached.
2283 Both policies utilize a dynamic aging mechanism that prevents
2284 cache pollution that can otherwise occur with frequency-based
2285 replacement policies.
2287 NOTE: if using the LFUDA replacement policy you should increase
2288 the value of maximum_object_size above its default of 4096 KB to
2289 to maximize the potential byte hit rate improvement of LFUDA.
2291 For more information about the GDSF and LFUDA cache replacement
2292 policies see http://www.hpl.hp.com/techreports/1999/HPL-1999-69.html
2293 and http://fog.hpl.external.hp.com/techreports/98/HPL-98-173.html.
2299 LOC: Config.cacheSwap
2303 cache_dir Type Directory-Name Fs-specific-data [options]
2305 You can specify multiple cache_dir lines to spread the
2306 cache among different disk partitions.
2308 Type specifies the kind of storage system to use. Only "ufs"
2309 is built by default. To enable any of the other storage systems
2310 see the --enable-storeio configure option.
2312 'Directory' is a top-level directory where cache swap
2313 files will be stored. If you want to use an entire disk
2314 for caching, this can be the mount-point directory.
2315 The directory must exist and be writable by the Squid
2316 process. Squid will NOT create this directory for you.
2320 "ufs" is the old well-known Squid storage format that has always
2323 cache_dir ufs Directory-Name Mbytes L1 L2 [options]
2325 'Mbytes' is the amount of disk space (MB) to use under this
2326 directory. The default is 100 MB. Change this to suit your
2327 configuration. Do NOT put the size of your disk drive here.
2328 Instead, if you want Squid to use the entire disk drive,
2329 subtract 20% and use that value.
2331 'Level-1' is the number of first-level subdirectories which
2332 will be created under the 'Directory'. The default is 16.
2334 'Level-2' is the number of second-level subdirectories which
2335 will be created under each first-level directory. The default
2338 The aufs store type:
2340 "aufs" uses the same storage format as "ufs", utilizing
2341 POSIX-threads to avoid blocking the main Squid process on
2342 disk-I/O. This was formerly known in Squid as async-io.
2344 cache_dir aufs Directory-Name Mbytes L1 L2 [options]
2346 see argument descriptions under ufs above
2348 The diskd store type:
2350 "diskd" uses the same storage format as "ufs", utilizing a
2351 separate process to avoid blocking the main Squid process on
2354 cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n]
2356 see argument descriptions under ufs above
2358 Q1 specifies the number of unacknowledged I/O requests when Squid
2359 stops opening new files. If this many messages are in the queues,
2360 Squid won't open new files. Default is 64
2362 Q2 specifies the number of unacknowledged messages when Squid
2363 starts blocking. If this many messages are in the queues,
2364 Squid blocks until it receives some replies. Default is 72
2366 When Q1 < Q2 (the default), the cache directory is optimized
2367 for lower response time at the expense of a decrease in hit
2368 ratio. If Q1 > Q2, the cache directory is optimized for
2369 higher hit ratio at the expense of an increase in response
2372 The coss store type:
2374 NP: COSS filesystem in Squid-3 has been deemed too unstable for
2375 production use and has thus been removed from this release.
2376 We hope that it can be made usable again soon.
2378 block-size=n defines the "block size" for COSS cache_dir's.
2379 Squid uses file numbers as block numbers. Since file numbers
2380 are limited to 24 bits, the block size determines the maximum
2381 size of the COSS partition. The default is 512 bytes, which
2382 leads to a maximum cache_dir size of 512<<24, or 8 GB. Note
2383 you should not change the coss block size after Squid
2384 has written some objects to the cache_dir.
2386 The coss file store has changed from 2.5. Now it uses a file
2387 called 'stripe' in the directory names in the config - and
2388 this will be created by squid -z.
2392 no-store, no new objects should be stored to this cache_dir
2394 max-size=n, refers to the max object size this storedir supports.
2395 It is used to initially choose the storedir to dump the object.
2396 Note: To make optimal use of the max-size limits you should order
2397 the cache_dir lines with the smallest max-size value first and the
2398 ones with no max-size specification last.
2400 Note for coss, max-size must be less than COSS_MEMBUF_SZ,
2401 which can be changed with the --with-coss-membuf-size=N configure
2405 # Uncomment and adjust the following to add a disk cache directory.
2406 #cache_dir ufs @DEFAULT_SWAP_DIR@ 100 16 256
2410 NAME: store_dir_select_algorithm
2412 LOC: Config.store_dir_select_algorithm
2415 Set this to 'round-robin' as an alternative.
2418 NAME: max_open_disk_fds
2420 LOC: Config.max_open_disk_fds
2423 To avoid having disk as the I/O bottleneck Squid can optionally
2424 bypass the on-disk cache if more than this amount of disk file
2425 descriptors are open.
2427 A value of 0 indicates no limit.
2430 NAME: minimum_object_size
2434 LOC: Config.Store.minObjectSize
2436 Objects smaller than this size will NOT be saved on disk. The
2437 value is specified in kilobytes, and the default is 0 KB, which
2438 means there is no minimum.
2441 NAME: maximum_object_size
2445 LOC: Config.Store.maxObjectSize
2447 Objects larger than this size will NOT be saved on disk. The
2448 value is specified in kilobytes, and the default is 4MB. If
2449 you wish to get a high BYTES hit ratio, you should probably
2450 increase this (one 32 MB object hit counts for 3200 10KB
2451 hits). If you wish to increase speed more than your want to
2452 save bandwidth you should leave this low.
2454 NOTE: if using the LFUDA replacement policy you should increase
2455 this value to maximize the byte hit rate improvement of LFUDA!
2456 See replacement_policy below for a discussion of this policy.
2459 NAME: cache_swap_low
2460 COMMENT: (percent, 0-100)
2463 LOC: Config.Swap.lowWaterMark
2466 NAME: cache_swap_high
2467 COMMENT: (percent, 0-100)
2470 LOC: Config.Swap.highWaterMark
2473 The low- and high-water marks for cache object replacement.
2474 Replacement begins when the swap (disk) usage is above the
2475 low-water mark and attempts to maintain utilization near the
2476 low-water mark. As swap utilization gets close to high-water
2477 mark object eviction becomes more aggressive. If utilization is
2478 close to the low-water mark less replacement is done each time.
2480 Defaults are 90% and 95%. If you have a large cache, 5% could be
2481 hundreds of MB. If this is the case you may wish to set these
2482 numbers closer together.
2487 -----------------------------------------------------------------------------
2492 LOC: Config.Log.logformats
2497 logformat <name> <format specification>
2499 Defines an access log format.
2501 The <format specification> is a string with embedded % format codes
2503 % format codes all follow the same basic structure where all but
2504 the formatcode is optional. Output strings are automatically escaped
2505 as required according to their context and the output format
2506 modifiers are usually not needed, but can be specified if an explicit
2507 output format is desired.
2509 % ["|[|'|#] [-] [[0]width] [{argument}] formatcode
2511 " output in quoted string format
2512 [ output in squid text log format as used by log_mime_hdrs
2513 # output in URL quoted format
2517 width field width. If starting with 0 the
2518 output is zero padded
2519 {arg} argument such as header name etc
2523 % a literal % character
2524 >a Client source IP address
2526 >p Client source port
2527 <A Server IP address or peer name
2528 la Local IP address (http_port)
2529 lp Local port number (http_port)
2530 sn Unique sequence number per log line entry
2531 ts Seconds since epoch
2532 tu subsecond time (milliseconds)
2533 tl Local time. Optional strftime format argument
2534 default %d/%b/%Y:%H:%M:%S %z
2535 tg GMT time. Optional strftime format argument
2536 default %d/%b/%Y:%H:%M:%S %z
2537 tr Response time (milliseconds)
2538 dt Total time spent making DNS lookups (milliseconds)
2540 HTTP cache related format codes:
2542 [http::]>h Original request header. Optional header name argument
2543 on the format header[:[separator]element]
2544 [http::]>ha The HTTP request headers after adaptation and redirection.
2545 Optional header name argument as for >h
2546 [http::]<h Reply header. Optional header name argument
2548 [http::]un User name
2549 [http::]ul User name from authentication
2550 [http::]ui User name from ident
2551 [http::]us User name from SSL
2552 [http::]ue User name from external acl helper
2553 [http::]>Hs HTTP status code sent to the client
2554 [http::]<Hs HTTP status code received from the next hop
2555 [http::]Ss Squid request status (TCP_MISS etc)
2556 [http::]Sh Squid hierarchy status (DEFAULT_PARENT etc)
2557 [http::]mt MIME content type
2558 [http::]rm Request method (GET/POST etc)
2559 [http::]ru Request URL
2560 [http::]rp Request URL-Path excluding hostname
2561 [http::]rv Request protocol version
2562 [http::]et Tag returned by external acl
2563 [http::]ea Log string returned by external acl
2564 [http::]<st Sent reply size including HTTP headers
2565 [http::]>st Received request size including HTTP headers. In the
2566 case of chunked requests the chunked encoding metadata
2568 [http::]>sh Received HTTP request headers size
2569 [http::]<sh Sent HTTP reply headers size
2570 [http::]st Request+Reply size including HTTP headers
2571 [http::]<sH Reply high offset sent
2572 [http::]<sS Upstream object size
2573 [http::]<pt Peer response time in milliseconds. The timer starts
2574 when the last request byte is sent to the next hop
2575 and stops when the last response byte is received.
2576 [http::]<tt Total server-side time in milliseconds. The timer
2577 starts with the first connect request (or write I/O)
2578 sent to the first selected peer. The timer stops
2579 with the last I/O with the last peer.
2581 If ICAP is enabled, the following two codes become available (as
2582 well as ICAP log codes documented with the icap_log option):
2584 icap::tt Total ICAP processing time for the HTTP
2585 transaction. The timer ticks when ICAP
2586 ACLs are checked and when ICAP
2587 transaction is in progress.
2589 icap::<last_h The header of the last ICAP response
2590 related to the HTTP transaction. Like
2591 <h, accepts an optional header name
2592 argument. Will not change semantics
2593 when multiple ICAP transactions per HTTP
2594 transaction are supported.
2596 If adaptation is enabled the following two codes become available:
2598 adapt::sum_trs Summed adaptation transaction response
2599 times recorded as a comma-separated list in
2600 the order of transaction start time. Each time
2601 value is recorded as an integer number,
2602 representing response time of one or more
2603 adaptation (ICAP or eCAP) transaction in
2604 milliseconds. When a failed transaction is
2605 being retried or repeated, its time is not
2606 logged individually but added to the
2607 replacement (next) transaction. See also:
2610 adapt::all_trs All adaptation transaction response times.
2611 Same as adaptation_strs but response times of
2612 individual transactions are never added
2613 together. Instead, all transaction response
2614 times are recorded individually.
2616 You can prefix adapt::*_trs format codes with adaptation
2617 service name in curly braces to record response time(s) specific
2618 to that service. For example: %{my_service}adapt::sum_trs
2620 The default formats available (which do not need re-defining) are:
2622 logformat squid %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %un %Sh/%<A %mt
2623 logformat squidmime %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %un %Sh/%<A %mt [%>h] [%<h]
2624 logformat common %>a %ui %un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st %Ss:%Sh
2625 logformat combined %>a %ui %un [%tl] "%rm %ru HTTP/%rv" %>Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
2628 NAME: access_log cache_access_log
2630 LOC: Config.Log.accesslogs
2632 DEFAULT_IF_NONE: daemon:@DEFAULT_ACCESS_LOG@ squid
2634 These files log client request activities. Has a line every HTTP or
2635 ICP request. The format is:
2636 access_log <module>:<place> [<logformat name> [acl acl ...]]
2637 access_log none [acl acl ...]]
2639 Will log to the specified module:place using the specified format (which
2640 must be defined in a logformat directive) those entries which match
2641 ALL the acl's specified (which must be defined in acl clauses).
2642 If no acl is specified, all requests will be logged to this destination.
2644 ===== Modules Currently available =====
2646 none Do not log any requests matchign these ACL.
2647 Do not specify Place or logformat name.
2649 stdio Write each log line to disk immediately at the completion of
2651 Place: the filename and path to be written.
2653 daemon Very similar to stdio. But instead of writing to disk the log
2654 line is passed to a daemon helper for asychronous handling instead.
2655 Place: varies depending on the daemon.
2657 log_file_daemon Place: the file name and path to be written.
2659 syslog To log each request via syslog facility.
2660 Place: The syslog facility and priority level for these entries.
2661 Place Format: facility.priority
2663 where facility could be any of:
2664 authpriv, daemon, local0 ... local7 or user.
2666 And priority could be any of:
2667 err, warning, notice, info, debug.
2669 udp To send each log line as text data to a UDP receiver.
2670 Place: The destination host name or IP and port.
2671 Place Format: \\host:port
2674 access_log daemon:@DEFAULT_ACCESS_LOG@ squid
2680 LOC: Config.Log.icaplogs
2683 ICAP log files record ICAP transaction summaries, one line per
2686 The icap_log option format is:
2687 icap_log <filepath> [<logformat name> [acl acl ...]]
2688 icap_log none [acl acl ...]]
2690 Please see access_log option documentation for details. The two
2691 kinds of logs share the overall configuration approach and many
2694 ICAP processing of a single HTTP message or transaction may
2695 require multiple ICAP transactions. In such cases, multiple
2696 ICAP transaction log lines will correspond to a single access
2699 ICAP log uses logformat codes that make sense for an ICAP
2700 transaction. Header-related codes are applied to the HTTP header
2701 embedded in an ICAP server response, with the following caveats:
2702 For REQMOD, there is no HTTP response header unless the ICAP
2703 server performed request satisfaction. For RESPMOD, the HTTP
2704 request header is the header sent to the ICAP server. For
2705 OPTIONS, there are no HTTP headers.
2707 The following format codes are also available for ICAP logs:
2709 icap::<A ICAP server IP address. Similar to <A.
2711 icap::<service_name ICAP service name from the icap_service
2712 option in Squid configuration file.
2714 icap::ru ICAP Request-URI. Similar to ru.
2716 icap::rm ICAP request method (REQMOD, RESPMOD, or
2717 OPTIONS). Similar to existing rm.
2719 icap::>st Bytes sent to the ICAP server (TCP payload
2720 only; i.e., what Squid writes to the socket).
2722 icap::<st Bytes received from the ICAP server (TCP
2723 payload only; i.e., what Squid reads from
2726 icap::tr Transaction response time (in
2727 milliseconds). The timer starts when
2728 the ICAP transaction is created and
2729 stops when the transaction is completed.
2732 icap::tio Transaction I/O time (in milliseconds). The
2733 timer starts when the first ICAP request
2734 byte is scheduled for sending. The timers
2735 stops when the last byte of the ICAP response
2738 icap::to Transaction outcome: ICAP_ERR* for all
2739 transaction errors, ICAP_OPT for OPTION
2740 transactions, ICAP_ECHO for 204
2741 responses, ICAP_MOD for message
2742 modification, and ICAP_SAT for request
2743 satisfaction. Similar to Ss.
2745 icap::Hs ICAP response status code. Similar to Hs.
2747 icap::>h ICAP request header(s). Similar to >h.
2749 icap::<h ICAP response header(s). Similar to <h.
2751 The default ICAP log format, which can be used without an explicit
2752 definition, is called icap_squid:
2754 logformat icap_squid %ts.%03tu %6icap::tr %>a %icap::to/%03icap::Hs %icap::<size %icap::rm %icap::ru% %un -/%icap::<A -
2756 See also: logformat, log_icap, and %icap::<last_h
2759 NAME: logfile_daemon
2761 DEFAULT: @DEFAULT_LOGFILED@
2762 LOC: Log::TheConfig.logfile_daemon
2764 Specify the path to the logfile-writing daemon. This daemon is
2765 used to write the access and store logs, if configured.
2770 LOC: Config.accessList.log
2772 COMMENT: allow|deny acl acl...
2774 This options allows you to control which requests gets logged
2775 to access.log (see access_log directive). Requests denied for
2776 logging will also not be accounted for in performance counters.
2778 This clause only supports fast acl types.
2779 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
2785 LOC: Config.accessList.icap
2788 This options allows you to control which requests get logged
2789 to icap.log. See the icap_log directive for ICAP log details.
2792 NAME: cache_store_log
2795 LOC: Config.Log.store
2797 Logs the activities of the storage manager. Shows which
2798 objects are ejected from the cache, and which objects are
2799 saved and for how long. To disable, enter "none" or remove the line.
2800 There are not really utilities to analyze this data, so you can safely
2804 cache_store_log @DEFAULT_STORE_LOG@
2807 NAME: cache_swap_state cache_swap_log
2809 LOC: Config.Log.swap
2812 Location for the cache "swap.state" file. This index file holds
2813 the metadata of objects saved on disk. It is used to rebuild
2814 the cache during startup. Normally this file resides in each
2815 'cache_dir' directory, but you may specify an alternate
2816 pathname here. Note you must give a full filename, not just
2817 a directory. Since this is the index for the whole object
2818 list you CANNOT periodically rotate it!
2820 If %s can be used in the file name it will be replaced with a
2821 a representation of the cache_dir name where each / is replaced
2822 with '.'. This is needed to allow adding/removing cache_dir
2823 lines when cache_swap_log is being used.
2825 If have more than one 'cache_dir', and %s is not used in the name
2826 these swap logs will have names such as:
2832 The numbered extension (which is added automatically)
2833 corresponds to the order of the 'cache_dir' lines in this
2834 configuration file. If you change the order of the 'cache_dir'
2835 lines in this file, these index files will NOT correspond to
2836 the correct 'cache_dir' entry (unless you manually rename
2837 them). We recommend you do NOT use this option. It is
2838 better to keep these index files in each 'cache_dir' directory.
2841 NAME: logfile_rotate
2844 LOC: Config.Log.rotateNumber
2846 Specifies the number of logfile rotations to make when you
2847 type 'squid -k rotate'. The default is 10, which will rotate
2848 with extensions 0 through 9. Setting logfile_rotate to 0 will
2849 disable the file name rotation, but the logfiles are still closed
2850 and re-opened. This will enable you to rename the logfiles
2851 yourself just before sending the rotate signal.
2853 Note, the 'squid -k rotate' command normally sends a USR1
2854 signal to the running squid process. In certain situations
2855 (e.g. on Linux with Async I/O), USR1 is used for other
2856 purposes, so -k rotate uses another signal. It is best to get
2857 in the habit of using 'squid -k rotate' instead of 'kill -USR1
2860 Note, from Squid-3.1 this option has no effect on the cache.log,
2861 that log can be rotated separately by using debug_options
2864 NAME: emulate_httpd_log
2868 LOC: Config.onoff.common_log
2870 The Cache can emulate the log file format which many 'httpd'
2871 programs use. To disable/enable this emulation, set
2872 emulate_httpd_log to 'off' or 'on'. The default
2873 is to use the native log format since it includes useful
2874 information Squid-specific log analyzers use.
2877 NAME: log_ip_on_direct
2881 LOC: Config.onoff.log_ip_on_direct
2883 Log the destination IP address in the hierarchy log tag when going
2884 direct. Earlier Squid versions logged the hostname here. If you
2885 prefer the old way set this to off.
2890 DEFAULT: @DEFAULT_MIME_TABLE@
2891 LOC: Config.mimeTablePathname
2893 Pathname to Squid's MIME table. You shouldn't need to change
2894 this, but the default file contains examples and formatting
2895 information if you do.
2901 LOC: Config.onoff.log_mime_hdrs
2904 The Cache can record both the request and the response MIME
2905 headers for each HTTP transaction. The headers are encoded
2906 safely and will appear as two bracketed fields at the end of
2907 the access log (for either the native or httpd-emulated log
2908 formats). To enable this logging set log_mime_hdrs to 'on'.
2913 LOC: Config.Log.useragent
2915 IFDEF: USE_USERAGENT_LOG
2917 Squid will write the User-Agent field from HTTP requests
2918 to the filename specified here. By default useragent_log
2922 NAME: referer_log referrer_log
2924 LOC: Config.Log.referer
2926 IFDEF: USE_REFERER_LOG
2928 Squid will write the Referer field from HTTP requests to the
2929 filename specified here. By default referer_log is disabled.
2930 Note that "referer" is actually a misspelling of "referrer"
2931 however the misspelt version has been accepted into the HTTP RFCs
2937 DEFAULT: @DEFAULT_PID_FILE@
2938 LOC: Config.pidFilename
2940 A filename to write the process-id to. To disable, enter "none".
2947 LOC: Config.onoff.log_fqdn
2949 Turn this on if you wish to log fully qualified domain names
2950 in the access.log. To do this Squid does a DNS lookup of all
2951 IP's connecting to it. This can (in some situations) increase
2952 latency, which makes your cache seem slower for interactive
2956 NAME: client_netmask
2958 LOC: Config.Addrs.client_netmask
2959 DEFAULT: 255.255.255.255
2961 A netmask for client addresses in logfiles and cachemgr output.
2962 Change this to protect the privacy of your cache clients.
2963 A netmask of 255.255.255.0 will log all IP's in that range with
2964 the last digit set to '0'.
2971 LOC: Config.Log.forward
2973 Logs the server-side requests.
2975 This is currently work in progress.
2978 NAME: strip_query_terms
2980 LOC: Config.onoff.strip_query_terms
2983 By default, Squid strips query terms from requested URLs before
2984 logging. This protects your user's privacy.
2991 LOC: Config.onoff.buffered_logs
2993 cache.log log file is written with stdio functions, and as such
2994 it can be buffered or unbuffered. By default it will be unbuffered.
2995 Buffering it can speed up the writing slightly (though you are
2996 unlikely to need to worry unless you run with tons of debugging
2997 enabled in which case performance will suffer badly anyway..).
3000 NAME: netdb_filename
3002 DEFAULT: @DEFAULT_NETDB_FILE@
3003 LOC: Config.netdbFilename
3006 A filename where Squid stores it's netdb state between restarts.
3007 To disable, enter "none".
3011 OPTIONS FOR TROUBLESHOOTING
3012 -----------------------------------------------------------------------------
3018 DEFAULT_IF_NONE: @DEFAULT_CACHE_LOG@
3019 LOC: Debug::cache_log
3021 Cache logging file. This is where general information about
3022 your cache's behavior goes. You can increase the amount of data
3023 logged to this file and how often its rotated with "debug_options"
3029 LOC: Debug::debugOptions
3031 Logging options are set as section,level where each source file
3032 is assigned a unique section. Lower levels result in less
3033 output, Full debugging (level 9) can result in a very large
3034 log file, so be careful.
3036 The magic word "ALL" sets debugging levels for all sections.
3037 We recommend normally running with "ALL,1".
3039 The rotate=N option can be used to keep more or less of these logs
3040 than would otherwise be kept by logfile_rotate.
3041 For most uses a single log should be enough to monitor current
3042 events affecting Squid.
3047 LOC: Config.coredump_dir
3049 DEFAULT_IF_NONE: none
3051 By default Squid leaves core files in the directory from where
3052 it was started. If you set 'coredump_dir' to a directory
3053 that exists, Squid will chdir() to that directory at startup
3054 and coredump files will be left there.
3058 # Leave coredumps in the first cache dir
3059 coredump_dir @DEFAULT_SWAP_DIR@
3065 OPTIONS FOR FTP GATEWAYING
3066 -----------------------------------------------------------------------------
3072 LOC: Config.Ftp.anon_user
3074 If you want the anonymous login password to be more informative
3075 (and enable the use of picky ftp servers), set this to something
3076 reasonable for your domain, like wwwuser@somewhere.net
3078 The reason why this is domainless by default is the
3079 request can be made on the behalf of a user in any domain,
3080 depending on how the cache is used.
3081 Some ftp server also validate the email address is valid
3082 (for example perl.com).
3088 LOC: Config.Ftp.passive
3090 If your firewall does not allow Squid to use passive
3091 connections, turn off this option.
3093 Use of ftp_epsv_all option requires this to be ON.
3099 LOC: Config.Ftp.epsv_all
3101 FTP Protocol extensions permit the use of a special "EPSV ALL" command.
3103 NATs may be able to put the connection on a "fast path" through the
3104 translator, as the EPRT command will never be used and therefore,
3105 translation of the data portion of the segments will never be needed.
3107 When a client only expects to do two-way FTP transfers this may be
3109 If squid finds that it must do a three-way FTP transfer after issuing
3110 an EPSV ALL command, the FTP session will fail.
3112 If you have any doubts about this option do not use it.
3113 Squid will nicely attempt all other connection methods.
3115 Requires ftp_passive to be ON (default) for any effect.
3121 LOC: Config.Ftp.epsv
3123 FTP Protocol extensions permit the use of a special "EPSV" command.
3125 NATs may be able to put the connection on a "fast path" through the
3126 translator using EPSV, as the EPRT command will never be used
3127 and therefore, translation of the data portion of the segments
3128 will never be needed.
3130 Turning this OFF will prevent EPSV being attempted.
3131 WARNING: Doing so will convert Squid back to the old behavior with all
3132 the related problems with external NAT devices/layers.
3134 Requires ftp_passive to be ON (default) for any effect.
3137 NAME: ftp_sanitycheck
3140 LOC: Config.Ftp.sanitycheck
3142 For security and data integrity reasons Squid by default performs
3143 sanity checks of the addresses of FTP data connections ensure the
3144 data connection is to the requested server. If you need to allow
3145 FTP connections to servers using another IP address for the data
3146 connection turn this off.
3149 NAME: ftp_telnet_protocol
3152 LOC: Config.Ftp.telnet
3154 The FTP protocol is officially defined to use the telnet protocol
3155 as transport channel for the control connection. However, many
3156 implementations are broken and does not respect this aspect of
3159 If you have trouble accessing files with ASCII code 255 in the
3160 path or similar problems involving this ASCII code you can
3161 try setting this directive to off. If that helps, report to the
3162 operator of the FTP server in question that their FTP server
3163 is broken and does not follow the FTP standard.
3167 OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
3168 -----------------------------------------------------------------------------
3173 DEFAULT: @DEFAULT_DISKD@
3174 LOC: Config.Program.diskd
3176 Specify the location of the diskd executable.
3177 Note this is only useful if you have compiled in
3178 diskd as one of the store io modules.
3181 NAME: unlinkd_program
3184 DEFAULT: @DEFAULT_UNLINKD@
3185 LOC: Config.Program.unlinkd
3187 Specify the location of the executable for file deletion process.
3190 NAME: pinger_program
3192 DEFAULT: @DEFAULT_PINGER@
3193 LOC: Config.pinger.program
3196 Specify the location of the executable for the pinger process.
3202 LOC: Config.pinger.enable
3205 Control whether the pinger is active at run-time.
3206 Enables turning ICMP pinger on and off with a simple
3207 squid -k reconfigure.
3212 OPTIONS FOR URL REWRITING
3213 -----------------------------------------------------------------------------
3216 NAME: url_rewrite_program redirect_program
3218 LOC: Config.Program.redirect
3221 Specify the location of the executable for the URL rewriter.
3222 Since they can perform almost any function there isn't one included.
3224 For each requested URL rewriter will receive on line with the format
3226 URL <SP> client_ip "/" fqdn <SP> user <SP> method [<SP> kvpairs]<NL>
3228 In the future, the rewriter interface will be extended with
3229 key=value pairs ("kvpairs" shown above). Rewriter programs
3230 should be prepared to receive and possibly ignore additional
3231 whitespace-separated tokens on each input line.
3233 And the rewriter may return a rewritten URL. The other components of
3234 the request line does not need to be returned (ignored if they are).
3236 The rewriter can also indicate that a client-side redirect should
3237 be performed to the new URL. This is done by prefixing the returned
3238 URL with "301:" (moved permanently) or 302: (moved temporarily).
3240 By default, a URL rewriter is not used.
3243 NAME: url_rewrite_children redirect_children
3244 TYPE: HelperChildConfig
3245 DEFAULT: 20 startup=0 idle=1 concurrency=0
3246 LOC: Config.redirectChildren
3248 The maximum number of redirector processes to spawn. If you limit
3249 it too few Squid will have to wait for them to process a backlog of
3250 URLs, slowing it down. If you allow too many they will use RAM
3251 and other system resources noticably.
3253 The startup= and idle= options allow some measure of skew in your
3258 Sets a minimum of how many processes are to be spawned when Squid
3259 starts or reconfigures. When set to zero the first request will
3260 cause spawning of the first child process to handle it.
3262 Starting too few will cause an initial slowdown in traffic as Squid
3263 attempts to simultaneously spawn enough processes to cope.
3267 Sets a minimum of how many processes Squid is to try and keep available
3268 at all times. When traffic begins to rise above what the existing
3269 processes can handle this many more will be spawned up to the maximum
3270 configured. A minimum setting of 1 is required.
3274 The number of requests each redirector helper can handle in
3275 parallel. Defaults to 0 which indicates the redirector
3276 is a old-style single threaded redirector.
3278 When this directive is set to a value >= 1 then the protocol
3279 used to communicate with the helper is modified to include
3280 a request ID in front of the request/response. The request
3281 ID from the request must be echoed back with the response
3285 NAME: url_rewrite_host_header redirect_rewrites_host_header
3288 LOC: Config.onoff.redir_rewrites_host
3290 By default Squid rewrites any Host: header in redirected
3291 requests. If you are running an accelerator this may
3292 not be a wanted effect of a redirector.
3294 WARNING: Entries are cached on the result of the URL rewriting
3295 process, so be careful if you have domain-virtual hosts.
3298 NAME: url_rewrite_access redirector_access
3301 LOC: Config.accessList.redirector
3303 If defined, this access list specifies which requests are
3304 sent to the redirector processes. By default all requests
3307 This clause supports both fast and slow acl types.
3308 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
3311 NAME: url_rewrite_bypass redirector_bypass
3313 LOC: Config.onoff.redirector_bypass
3316 When this is 'on', a request will not go through the
3317 redirector if all redirectors are busy. If this is 'off'
3318 and the redirector queue grows too large, Squid will exit
3319 with a FATAL error and ask you to increase the number of
3320 redirectors. You should only enable this if the redirectors
3321 are not critical to your caching system. If you use
3322 redirectors for access control, and you enable this option,
3323 users may have access to pages they should not
3324 be allowed to request.
3328 OPTIONS FOR TUNING THE CACHE
3329 -----------------------------------------------------------------------------
3332 NAME: cache no_cache
3335 LOC: Config.accessList.noCache
3337 A list of ACL elements which, if matched and denied, cause the request to
3338 not be satisfied from the cache and the reply to not be cached.
3339 In other words, use this to force certain objects to never be cached.
3341 You must use the words 'allow' or 'deny' to indicate whether items
3342 matching the ACL should be allowed or denied into the cache.
3344 Default is to allow all to be cached.
3346 This clause supports both fast and slow acl types.
3347 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
3350 NAME: refresh_pattern
3351 TYPE: refreshpattern
3355 usage: refresh_pattern [-i] regex min percent max [options]
3357 By default, regular expressions are CASE-SENSITIVE. To make
3358 them case-insensitive, use the -i option.
3360 'Min' is the time (in minutes) an object without an explicit
3361 expiry time should be considered fresh. The recommended
3362 value is 0, any higher values may cause dynamic applications
3363 to be erroneously cached unless the application designer
3364 has taken the appropriate actions.
3366 'Percent' is a percentage of the objects age (time since last
3367 modification age) an object without explicit expiry time
3368 will be considered fresh.
3370 'Max' is an upper limit on how long objects without an explicit
3371 expiry time will be considered fresh.
3373 options: override-expire
3379 ignore-must-revalidate
3384 override-expire enforces min age even if the server
3385 sent an explicit expiry time (e.g., with the
3386 Expires: header or Cache-Control: max-age). Doing this
3387 VIOLATES the HTTP standard. Enabling this feature
3388 could make you liable for problems which it causes.
3390 Note: override-expire does not enforce staleness - it only extends
3391 freshness / min. If the server returns a Expires time which
3392 is longer than your max time, Squid will still consider
3393 the object fresh for that period of time.
3395 override-lastmod enforces min age even on objects
3396 that were modified recently.
3398 reload-into-ims changes client no-cache or ``reload''
3399 to If-Modified-Since requests. Doing this VIOLATES the
3400 HTTP standard. Enabling this feature could make you
3401 liable for problems which it causes.
3403 ignore-reload ignores a client no-cache or ``reload''
3404 header. Doing this VIOLATES the HTTP standard. Enabling
3405 this feature could make you liable for problems which
3408 ignore-no-cache ignores any ``Pragma: no-cache'' and
3409 ``Cache-control: no-cache'' headers received from a server.
3410 The HTTP RFC never allows the use of this (Pragma) header
3411 from a server, only a client, though plenty of servers
3414 ignore-no-store ignores any ``Cache-control: no-store''
3415 headers received from a server. Doing this VIOLATES
3416 the HTTP standard. Enabling this feature could make you
3417 liable for problems which it causes.
3419 ignore-must-revalidate ignores any ``Cache-Control: must-revalidate``
3420 headers received from a server. Doing this VIOLATES
3421 the HTTP standard. Enabling this feature could make you
3422 liable for problems which it causes.
3424 ignore-private ignores any ``Cache-control: private''
3425 headers received from a server. Doing this VIOLATES
3426 the HTTP standard. Enabling this feature could make you
3427 liable for problems which it causes.
3429 ignore-auth caches responses to requests with authorization,
3430 as if the originserver had sent ``Cache-control: public''
3431 in the response header. Doing this VIOLATES the HTTP standard.
3432 Enabling this feature could make you liable for problems which
3435 refresh-ims causes squid to contact the origin server
3436 when a client issues an If-Modified-Since request. This
3437 ensures that the client will receive an updated version
3438 if one is available.
3440 Basically a cached object is:
3442 FRESH if expires < now, else STALE
3444 FRESH if lm-factor < percent, else STALE
3448 The refresh_pattern lines are checked in the order listed here.
3449 The first entry which matches is used. If none of the entries
3450 match the default will be used.
3452 Note, you must uncomment all the default lines if you want
3453 to change one. The default setting is only active if none is
3458 # Add any of your own refresh_pattern entries above these.
3459 refresh_pattern ^ftp: 1440 20% 10080
3460 refresh_pattern ^gopher: 1440 0% 1440
3461 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0
3462 refresh_pattern . 0 20% 4320
3466 NAME: quick_abort_min
3470 LOC: Config.quickAbort.min
3473 NAME: quick_abort_max
3477 LOC: Config.quickAbort.max
3480 NAME: quick_abort_pct
3484 LOC: Config.quickAbort.pct
3486 The cache by default continues downloading aborted requests
3487 which are almost completed (less than 16 KB remaining). This
3488 may be undesirable on slow (e.g. SLIP) links and/or very busy
3489 caches. Impatient users may tie up file descriptors and
3490 bandwidth by repeatedly requesting and immediately aborting
3493 When the user aborts a request, Squid will check the
3494 quick_abort values to the amount of data transfered until
3497 If the transfer has less than 'quick_abort_min' KB remaining,
3498 it will finish the retrieval.
3500 If the transfer has more than 'quick_abort_max' KB remaining,
3501 it will abort the retrieval.
3503 If more than 'quick_abort_pct' of the transfer has completed,
3504 it will finish the retrieval.
3506 If you do not want any retrieval to continue after the client
3507 has aborted, set both 'quick_abort_min' and 'quick_abort_max'
3510 If you want retrievals to always continue if they are being
3511 cached set 'quick_abort_min' to '-1 KB'.
3514 NAME: read_ahead_gap
3515 COMMENT: buffer-size
3517 LOC: Config.readAheadGap
3520 The amount of data the cache will buffer ahead of what has been
3521 sent to the client when retrieving an object from another server.
3525 IFDEF: HTTP_VIOLATIONS
3528 LOC: Config.negativeTtl
3531 Set the Default Time-to-Live (TTL) for failed requests.
3532 Certain types of failures (such as "connection refused" and
3533 "404 Not Found") are able to be negatively-cached for a short time.
3534 Modern web servers should provide Expires: header, however if they
3535 do not this can provide a minimum TTL.
3536 The default is not to cache errors with unknown expiry details.
3538 Note that this is different from negative caching of DNS lookups.
3540 WARNING: Doing this VIOLATES the HTTP standard. Enabling
3541 this feature could make you liable for problems which it
3545 NAME: positive_dns_ttl
3548 LOC: Config.positiveDnsTtl
3551 Upper limit on how long Squid will cache positive DNS responses.
3552 Default is 6 hours (360 minutes). This directive must be set
3553 larger than negative_dns_ttl.
3556 NAME: negative_dns_ttl
3559 LOC: Config.negativeDnsTtl
3562 Time-to-Live (TTL) for negative caching of failed DNS lookups.
3563 This also sets the lower cache limit on positive lookups.
3564 Minimum value is 1 second, and it is not recommendable to go
3565 much below 10 seconds.
3568 NAME: range_offset_limit
3569 COMMENT: size [acl acl...]
3571 LOC: Config.rangeOffsetLimit
3574 usage: (size) [units] [[!]aclname]
3576 Sets an upper limit on how far (number of bytes) into the file
3577 a Range request may be to cause Squid to prefetch the whole file.
3578 If beyond this limit, Squid forwards the Range request as it is and
3579 the result is NOT cached.
3581 This is to stop a far ahead range request (lets say start at 17MB)
3582 from making Squid fetch the whole object up to that point before
3583 sending anything to the client.
3585 Multiple range_offset_limit lines may be specified, and they will
3586 be searched from top to bottom on each request until a match is found.
3587 The first match found will be used. If no line matches a request, the
3588 default limit of 0 bytes will be used.
3590 'size' is the limit specified as a number of units.
3592 'units' specifies whether to use bytes, KB, MB, etc.
3593 If no units are specified bytes are assumed.
3595 A size of 0 causes Squid to never fetch more than the
3596 client requested. (default)
3598 A size of 'none' causes Squid to always fetch the object from the
3599 beginning so it may cache the result. (2.0 style)
3601 'aclname' is the name of a defined ACL.
3603 NP: Using 'none' as the byte value here will override any quick_abort settings
3604 that may otherwise apply to the range request. The range request will
3605 be fully fetched from start to finish regardless of the client
3606 actions. This affects bandwidth usage.
3609 NAME: minimum_expiry_time
3612 LOC: Config.minimum_expiry_time
3615 The minimum caching time according to (Expires - Date)
3616 Headers Squid honors if the object can't be revalidated
3617 defaults to 60 seconds. In reverse proxy environments it
3618 might be desirable to honor shorter object lifetimes. It
3619 is most likely better to make your server return a
3620 meaningful Last-Modified header however. In ESI environments
3621 where page fragments often have short lifetimes, this will
3622 often be best set to 0.
3625 NAME: store_avg_object_size
3629 LOC: Config.Store.avgObjectSize
3631 Average object size, used to estimate number of objects your
3632 cache can hold. The default is 13 KB.
3635 NAME: store_objects_per_bucket
3638 LOC: Config.Store.objectsPerBucket
3640 Target number of objects per bucket in the store hash table.
3641 Lowering this value increases the total number of buckets and
3642 also the storage maintenance rate. The default is 20.
3647 -----------------------------------------------------------------------------
3650 NAME: request_header_max_size
3654 LOC: Config.maxRequestHeaderSize
3656 This specifies the maximum size for HTTP headers in a request.
3657 Request headers are usually relatively small (about 512 bytes).
3658 Placing a limit on the request header size will catch certain
3659 bugs (for example with persistent connections) and possibly
3660 buffer-overflow or denial-of-service attacks.
3663 NAME: reply_header_max_size
3667 LOC: Config.maxReplyHeaderSize
3669 This specifies the maximum size for HTTP headers in a reply.
3670 Reply headers are usually relatively small (about 512 bytes).
3671 Placing a limit on the reply header size will catch certain
3672 bugs (for example with persistent connections) and possibly
3673 buffer-overflow or denial-of-service attacks.
3676 NAME: request_body_max_size
3680 LOC: Config.maxRequestBodySize
3682 This specifies the maximum size for an HTTP request body.
3683 In other words, the maximum size of a PUT/POST request.
3684 A user who attempts to send a request with a body larger
3685 than this limit receives an "Invalid Request" error message.
3686 If you set this parameter to a zero (the default), there will
3687 be no limit imposed.
3690 NAME: chunked_request_body_max_size
3694 LOC: Config.maxChunkedRequestBodySize
3696 A broken or confused HTTP/1.1 client may send a chunked HTTP
3697 request to Squid. Squid does not have full support for that
3698 feature yet. To cope with such requests, Squid buffers the
3699 entire request and then dechunks request body to create a
3700 plain HTTP/1.0 request with a known content length. The plain
3701 request is then used by the rest of Squid code as usual.
3703 The option value specifies the maximum size of the buffer used
3704 to hold the request before the conversion. If the chunked
3705 request size exceeds the specified limit, the conversion
3706 fails, and the client receives an "unsupported request" error,
3707 as if dechunking was disabled.
3709 Dechunking is enabled by default. To disable conversion of
3710 chunked requests, set the maximum to zero.
3712 Request dechunking feature and this option in particular are a
3713 temporary hack. When chunking requests and responses are fully
3714 supported, there will be no need to buffer a chunked request.
3718 IFDEF: HTTP_VIOLATIONS
3721 LOC: Config.accessList.brokenPosts
3723 A list of ACL elements which, if matched, causes Squid to send
3724 an extra CRLF pair after the body of a PUT/POST request.
3726 Some HTTP servers has broken implementations of PUT/POST,
3727 and rely on an extra CRLF pair sent by some WWW clients.
3729 Quote from RFC2616 section 4.1 on this matter:
3731 Note: certain buggy HTTP/1.0 client implementations generate an
3732 extra CRLF's after a POST request. To restate what is explicitly
3733 forbidden by the BNF, an HTTP/1.1 client must not preface or follow
3734 a request with an extra CRLF.
3736 This clause only supports fast acl types.
3737 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
3740 acl buggy_server url_regex ^http://....
3741 broken_posts allow buggy_server
3744 NAME: icap_uses_indirect_client
3747 IFDEF: FOLLOW_X_FORWARDED_FOR&&ICAP_CLIENT
3749 LOC: Adaptation::Icap::TheConfig.icap_uses_indirect_client
3751 Controls whether the indirect client address
3752 (see follow_x_forwarded_for) instead of the
3753 direct client address is passed to an ICAP
3754 server as "X-Client-IP".
3758 IFDEF: HTTP_VIOLATIONS
3762 LOC: Config.onoff.via
3764 If set (default), Squid will include a Via header in requests and
3765 replies as required by RFC2616.
3771 LOC: Config.onoff.ie_refresh
3774 Microsoft Internet Explorer up until version 5.5 Service
3775 Pack 1 has an issue with transparent proxies, wherein it
3776 is impossible to force a refresh. Turning this on provides
3777 a partial fix to the problem, by causing all IMS-REFRESH
3778 requests from older IE versions to check the origin server
3779 for fresh content. This reduces hit ratio by some amount
3780 (~10% in my experience), but allows users to actually get
3781 fresh content when they want it. Note because Squid
3782 cannot tell if the user is using 5.5 or 5.5SP1, the behavior
3783 of 5.5 is unchanged from old versions of Squid (i.e. a
3784 forced refresh is impossible). Newer versions of IE will,
3785 hopefully, continue to have the new behavior and will be
3786 handled based on that assumption. This option defaults to
3787 the old Squid behavior, which is better for hit ratios but
3788 worse for clients using IE, if they need to be able to
3789 force fresh content.
3792 NAME: vary_ignore_expire
3795 LOC: Config.onoff.vary_ignore_expire
3798 Many HTTP servers supporting Vary gives such objects
3799 immediate expiry time with no cache-control header
3800 when requested by a HTTP/1.0 client. This option
3801 enables Squid to ignore such expiry times until
3802 HTTP/1.1 is fully implemented.
3804 WARNING: If turned on this may eventually cause some
3805 varying objects not intended for caching to get cached.
3808 NAME: request_entities
3810 LOC: Config.onoff.request_entities
3813 Squid defaults to deny GET and HEAD requests with request entities,
3814 as the meaning of such requests are undefined in the HTTP standard
3815 even if not explicitly forbidden.
3817 Set this directive to on if you have clients which insists
3818 on sending request entities in GET or HEAD requests. But be warned
3819 that there is server software (both proxies and web servers) which
3820 can fail to properly process this kind of request which may make you
3821 vulnerable to cache pollution attacks if enabled.
3824 NAME: request_header_access
3825 IFDEF: HTTP_VIOLATIONS
3826 TYPE: http_header_access[]
3827 LOC: Config.request_header_access
3830 Usage: request_header_access header_name allow|deny [!]aclname ...
3832 WARNING: Doing this VIOLATES the HTTP standard. Enabling
3833 this feature could make you liable for problems which it
3836 This option replaces the old 'anonymize_headers' and the
3837 older 'http_anonymizer' option with something that is much
3838 more configurable. This new method creates a list of ACLs
3839 for each header, allowing you very fine-tuned header
3842 This option only applies to request headers, i.e., from the
3843 client to the server.
3845 You can only specify known headers for the header name.
3846 Other headers are reclassified as 'Other'. You can also
3847 refer to all the headers with 'All'.
3849 For example, to achieve the same behavior as the old
3850 'http_anonymizer standard' option, you should use:
3852 request_header_access From deny all
3853 request_header_access Referer deny all
3854 request_header_access Server deny all
3855 request_header_access User-Agent deny all
3856 request_header_access WWW-Authenticate deny all
3857 request_header_access Link deny all
3859 Or, to reproduce the old 'http_anonymizer paranoid' feature
3862 request_header_access Allow allow all
3863 request_header_access Authorization allow all
3864 request_header_access WWW-Authenticate allow all
3865 request_header_access Proxy-Authorization allow all
3866 request_header_access Proxy-Authenticate allow all
3867 request_header_access Cache-Control allow all
3868 request_header_access Content-Encoding allow all
3869 request_header_access Content-Length allow all
3870 request_header_access Content-Type allow all
3871 request_header_access Date allow all
3872 request_header_access Expires allow all
3873 request_header_access Host allow all
3874 request_header_access If-Modified-Since allow all
3875 request_header_access Last-Modified allow all
3876 request_header_access Location allow all
3877 request_header_access Pragma allow all
3878 request_header_access Accept allow all
3879 request_header_access Accept-Charset allow all
3880 request_header_access Accept-Encoding allow all
3881 request_header_access Accept-Language allow all
3882 request_header_access Content-Language allow all
3883 request_header_access Mime-Version allow all
3884 request_header_access Retry-After allow all
3885 request_header_access Title allow all
3886 request_header_access Connection allow all
3887 request_header_access Proxy-Connection allow all
3888 request_header_access All deny all
3890 although many of those are HTTP reply headers, and so should be
3891 controlled with the reply_header_access directive.
3893 By default, all headers are allowed (no anonymizing is
3897 NAME: reply_header_access
3898 IFDEF: HTTP_VIOLATIONS
3899 TYPE: http_header_access[]
3900 LOC: Config.reply_header_access
3903 Usage: reply_header_access header_name allow|deny [!]aclname ...
3905 WARNING: Doing this VIOLATES the HTTP standard. Enabling
3906 this feature could make you liable for problems which it
3909 This option only applies to reply headers, i.e., from the
3910 server to the client.
3912 This is the same as request_header_access, but in the other
3915 This option replaces the old 'anonymize_headers' and the
3916 older 'http_anonymizer' option with something that is much
3917 more configurable. This new method creates a list of ACLs
3918 for each header, allowing you very fine-tuned header
3921 You can only specify known headers for the header name.
3922 Other headers are reclassified as 'Other'. You can also
3923 refer to all the headers with 'All'.
3925 For example, to achieve the same behavior as the old
3926 'http_anonymizer standard' option, you should use:
3928 reply_header_access From deny all
3929 reply_header_access Referer deny all
3930 reply_header_access Server deny all
3931 reply_header_access User-Agent deny all
3932 reply_header_access WWW-Authenticate deny all
3933 reply_header_access Link deny all
3935 Or, to reproduce the old 'http_anonymizer paranoid' feature
3938 reply_header_access Allow allow all
3939 reply_header_access Authorization allow all
3940 reply_header_access WWW-Authenticate allow all
3941 reply_header_access Proxy-Authorization allow all
3942 reply_header_access Proxy-Authenticate allow all
3943 reply_header_access Cache-Control allow all
3944 reply_header_access Content-Encoding allow all
3945 reply_header_access Content-Length allow all
3946 reply_header_access Content-Type allow all
3947 reply_header_access Date allow all
3948 reply_header_access Expires allow all
3949 reply_header_access Host allow all
3950 reply_header_access If-Modified-Since allow all
3951 reply_header_access Last-Modified allow all
3952 reply_header_access Location allow all
3953 reply_header_access Pragma allow all
3954 reply_header_access Accept allow all
3955 reply_header_access Accept-Charset allow all
3956 reply_header_access Accept-Encoding allow all
3957 reply_header_access Accept-Language allow all
3958 reply_header_access Content-Language allow all
3959 reply_header_access Mime-Version allow all
3960 reply_header_access Retry-After allow all
3961 reply_header_access Title allow all
3962 reply_header_access Connection allow all
3963 reply_header_access Proxy-Connection allow all
3964 reply_header_access All deny all
3966 although the HTTP request headers won't be usefully controlled
3967 by this directive -- see request_header_access for details.
3969 By default, all headers are allowed (no anonymizing is
3973 NAME: header_replace
3974 IFDEF: HTTP_VIOLATIONS
3975 TYPE: http_header_replace[]
3976 LOC: Config.request_header_access
3979 Usage: header_replace header_name message
3980 Example: header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
3982 This option allows you to change the contents of headers
3983 denied with header_access above, by replacing them with
3984 some fixed string. This replaces the old fake_user_agent
3987 This only applies to request headers, not reply headers.
3989 By default, headers are removed if denied.
3992 NAME: relaxed_header_parser
3993 COMMENT: on|off|warn
3995 LOC: Config.onoff.relaxed_header_parser
3998 In the default "on" setting Squid accepts certain forms
3999 of non-compliant HTTP messages where it is unambiguous
4000 what the sending application intended even if the message
4001 is not correctly formatted. The messages is then normalized
4002 to the correct form when forwarded by Squid.
4004 If set to "warn" then a warning will be emitted in cache.log
4005 each time such HTTP error is encountered.
4007 If set to "off" then such HTTP errors will cause the request
4008 or response to be rejected.
4011 NAME: ignore_expect_100
4013 IFDEF: HTTP_VIOLATIONS
4015 LOC: Config.onoff.ignore_expect_100
4018 This option makes Squid ignore any Expect: 100-continue header present
4019 in the request. RFC 2616 requires that Squid being unable to satisfy
4020 the response expectation MUST return a 417 error.
4022 Note: Enabling this is a HTTP protocol violation, but some clients may
4023 not handle it well..
4028 -----------------------------------------------------------------------------
4031 NAME: forward_timeout
4034 LOC: Config.Timeout.forward
4037 This parameter specifies how long Squid should at most attempt in
4038 finding a forwarding path for the request before giving up.
4041 NAME: connect_timeout
4044 LOC: Config.Timeout.connect
4047 This parameter specifies how long to wait for the TCP connect to
4048 the requested server or peer to complete before Squid should
4049 attempt to find another path where to forward the request.
4052 NAME: peer_connect_timeout
4055 LOC: Config.Timeout.peer_connect
4058 This parameter specifies how long to wait for a pending TCP
4059 connection to a peer cache. The default is 30 seconds. You
4060 may also set different timeout values for individual neighbors
4061 with the 'connect-timeout' option on a 'cache_peer' line.
4067 LOC: Config.Timeout.read
4070 The read_timeout is applied on server-side connections. After
4071 each successful read(), the timeout will be extended by this
4072 amount. If no data is read again after this amount of time,
4073 the request is aborted and logged with ERR_READ_TIMEOUT. The
4074 default is 15 minutes.
4080 LOC: Config.Timeout.write
4083 This timeout is tracked for all connections that have data
4084 available for writing and are waiting for the socket to become
4085 ready. After each successful write, the timeout is extended by
4086 the configured amount. If Squid has data to write but the
4087 connection is not ready for the configured duration, the
4088 transaction associated with the connection is terminated. The
4089 default is 15 minutes.
4092 NAME: request_timeout
4094 LOC: Config.Timeout.request
4097 How long to wait for an HTTP request after initial
4098 connection establishment.
4101 NAME: persistent_request_timeout
4103 LOC: Config.Timeout.persistent_request
4106 How long to wait for the next HTTP request on a persistent
4107 connection after the previous request completes.
4110 NAME: client_lifetime
4113 LOC: Config.Timeout.lifetime
4116 The maximum amount of time a client (browser) is allowed to
4117 remain connected to the cache process. This protects the Cache
4118 from having a lot of sockets (and hence file descriptors) tied up
4119 in a CLOSE_WAIT state from remote clients that go away without
4120 properly shutting down (either because of a network failure or
4121 because of a poor client implementation). The default is one
4124 NOTE: The default value is intended to be much larger than any
4125 client would ever need to be connected to your cache. You
4126 should probably change client_lifetime only as a last resort.
4127 If you seem to have many client connections tying up
4128 filedescriptors, we recommend first tuning the read_timeout,
4129 request_timeout, persistent_request_timeout and quick_abort values.
4132 NAME: half_closed_clients
4134 LOC: Config.onoff.half_closed_clients
4137 Some clients may shutdown the sending side of their TCP
4138 connections, while leaving their receiving sides open. Sometimes,
4139 Squid can not tell the difference between a half-closed and a
4140 fully-closed TCP connection.
4142 By default, Squid will immediately close client connections when
4143 read(2) returns "no more data to read."
4145 Change this option to 'on' and Squid will keep open connections
4146 until a read(2) or write(2) on the socket returns an error.
4147 This may show some benefits for reverse proxies. But if not
4148 it is recommended to leave OFF.
4153 LOC: Config.Timeout.pconn
4156 Timeout for idle persistent connections to servers and other
4163 LOC: Ident::TheConfig.timeout
4166 Maximum time to wait for IDENT lookups to complete.
4168 If this is too high, and you enabled IDENT lookups from untrusted
4169 users, you might be susceptible to denial-of-service by having
4170 many ident requests going at once.
4173 NAME: shutdown_lifetime
4176 LOC: Config.shutdownLifetime
4179 When SIGTERM or SIGHUP is received, the cache is put into
4180 "shutdown pending" mode until all active sockets are closed.
4181 This value is the lifetime to set for all open descriptors
4182 during shutdown mode. Any active clients after this many
4183 seconds will receive a 'timeout' message.
4187 ADMINISTRATIVE PARAMETERS
4188 -----------------------------------------------------------------------------
4194 LOC: Config.adminEmail
4196 Email-address of local cache manager who will receive
4197 mail if the cache dies. The default is "webmaster."
4203 LOC: Config.EmailFrom
4205 From: email-address for mail sent when the cache dies.
4206 The default is to use 'appname@unique_hostname'.
4207 Default appname value is "squid", can be changed into
4208 src/globals.h before building squid.
4214 LOC: Config.EmailProgram
4216 Email program used to send mail if the cache dies.
4217 The default is "mail". The specified program must comply
4218 with the standard Unix mail syntax:
4219 mail-program recipient < mailfile
4221 Optional command line options can be specified.
4224 NAME: cache_effective_user
4226 DEFAULT: @DEFAULT_CACHE_EFFECTIVE_USER@
4227 LOC: Config.effectiveUser
4229 If you start Squid as root, it will change its effective/real
4230 UID/GID to the user specified below. The default is to change
4231 to UID of @DEFAULT_CACHE_EFFECTIVE_USER@.
4232 see also; cache_effective_group
4235 NAME: cache_effective_group
4238 LOC: Config.effectiveGroup
4240 Squid sets the GID to the effective user's default group ID
4241 (taken from the password file) and supplementary group list
4242 from the groups membership.
4244 If you want Squid to run with a specific GID regardless of
4245 the group memberships of the effective user then set this
4246 to the group (or GID) you want Squid to run as. When set
4247 all other group privileges of the effective user are ignored
4248 and only this GID is effective. If Squid is not started as
4249 root the user starting Squid MUST be member of the specified
4252 This option is not recommended by the Squid Team.
4253 Our preference is for administrators to configure a secure
4254 user account for squid with UID/GID matching system policies.
4257 NAME: httpd_suppress_version_string
4261 LOC: Config.onoff.httpd_suppress_version_string
4263 Suppress Squid version string info in HTTP headers and HTML error pages.
4266 NAME: visible_hostname
4268 LOC: Config.visibleHostname
4271 If you want to present a special hostname in error messages, etc,
4272 define this. Otherwise, the return value of gethostname()
4273 will be used. If you have multiple caches in a cluster and
4274 get errors about IP-forwarding you must set them to have individual
4275 names with this setting.
4278 NAME: unique_hostname
4280 LOC: Config.uniqueHostname
4283 If you want to have multiple machines with the same
4284 'visible_hostname' you must give each machine a different
4285 'unique_hostname' so forwarding loops can be detected.
4288 NAME: hostname_aliases
4290 LOC: Config.hostnameAliases
4293 A list of other DNS names your cache has.
4301 Minimum umask which should be enforced while the proxy
4302 is running, in addition to the umask set at startup.
4304 For a traditional octal representation of umasks, start
4309 OPTIONS FOR THE CACHE REGISTRATION SERVICE
4310 -----------------------------------------------------------------------------
4312 This section contains parameters for the (optional) cache
4313 announcement service. This service is provided to help
4314 cache administrators locate one another in order to join or
4315 create cache hierarchies.
4317 An 'announcement' message is sent (via UDP) to the registration
4318 service by Squid. By default, the announcement message is NOT
4319 SENT unless you enable it with 'announce_period' below.
4321 The announcement message includes your hostname, plus the
4322 following information from this configuration file:
4328 All current information is processed regularly and made
4329 available on the Web at http://www.ircache.net/Cache/Tracker/.
4332 NAME: announce_period
4334 LOC: Config.Announce.period
4337 This is how frequently to send cache announcements. The
4338 default is `0' which disables sending the announcement
4341 To enable announcing your cache, just set an announce period.
4344 announce_period 1 day
4349 DEFAULT: tracker.ircache.net
4350 LOC: Config.Announce.host
4356 LOC: Config.Announce.file
4362 LOC: Config.Announce.port
4364 announce_host and announce_port set the hostname and port
4365 number where the registration message will be sent.
4367 Hostname will default to 'tracker.ircache.net' and port will
4368 default default to 3131. If the 'filename' argument is given,
4369 the contents of that file will be included in the announce
4374 HTTPD-ACCELERATOR OPTIONS
4375 -----------------------------------------------------------------------------
4378 NAME: httpd_accel_surrogate_id
4381 LOC: Config.Accel.surrogate_id
4383 Surrogates (http://www.esi.org/architecture_spec_1.0.html)
4384 need an identification token to allow control targeting. Because
4385 a farm of surrogates may all perform the same tasks, they may share
4386 an identification token.
4388 The default ID is the visible_hostname
4391 NAME: http_accel_surrogate_remote
4395 LOC: Config.onoff.surrogate_is_remote
4397 Remote surrogates (such as those in a CDN) honour Surrogate-Control: no-store-remote.
4398 Set this to on to have squid behave as a remote surrogate.
4402 IFDEF: USE_SQUID_ESI
4403 COMMENT: libxml2|expat|custom
4405 LOC: ESIParser::Type
4408 ESI markup is not strictly XML compatible. The custom ESI parser
4409 will give higher performance, but cannot handle non ASCII character
4414 DELAY POOL PARAMETERS
4415 -----------------------------------------------------------------------------
4419 TYPE: delay_pool_count
4424 This represents the number of delay pools to be used. For example,
4425 if you have one class 2 delay pool and one class 3 delays pool, you
4426 have a total of 2 delay pools.
4430 TYPE: delay_pool_class
4435 This defines the class of each delay pool. There must be exactly one
4436 delay_class line for each delay pool. For example, to define two
4437 delay pools, one of class 2 and one of class 3, the settings above
4441 delay_pools 4 # 4 delay pools
4442 delay_class 1 2 # pool 1 is a class 2 pool
4443 delay_class 2 3 # pool 2 is a class 3 pool
4444 delay_class 3 4 # pool 3 is a class 4 pool
4445 delay_class 4 5 # pool 4 is a class 5 pool
4447 The delay pool classes are:
4449 class 1 Everything is limited by a single aggregate
4452 class 2 Everything is limited by a single aggregate
4453 bucket as well as an "individual" bucket chosen
4454 from bits 25 through 32 of the IPv4 address.
4456 class 3 Everything is limited by a single aggregate
4457 bucket as well as a "network" bucket chosen
4458 from bits 17 through 24 of the IP address and a
4459 "individual" bucket chosen from bits 17 through
4460 32 of the IPv4 address.
4462 class 4 Everything in a class 3 delay pool, with an
4463 additional limit on a per user basis. This
4464 only takes effect if the username is established
4465 in advance - by forcing authentication in your
4468 class 5 Requests are grouped according their tag (see
4469 external_acl's tag= reply).
4471 NOTE: If an IP address is a.b.c.d
4472 -> bits 25 through 32 are "d"
4473 -> bits 17 through 24 are "c"
4474 -> bits 17 through 32 are "c * 256 + d"
4476 NOTE-2: Due to the use of bitmasks in class 2,3,4 pools they only apply to
4477 IPv4 traffic. Class 1 and 5 pools may be used with IPv6 traffic.
4481 TYPE: delay_pool_access
4486 This is used to determine which delay pool a request falls into.
4488 delay_access is sorted per pool and the matching starts with pool 1,
4489 then pool 2, ..., and finally pool N. The first delay pool where the
4490 request is allowed is selected for the request. If it does not allow
4491 the request to any pool then the request is not delayed (default).
4493 For example, if you want some_big_clients in delay
4494 pool 1 and lotsa_little_clients in delay pool 2:
4497 delay_access 1 allow some_big_clients
4498 delay_access 1 deny all
4499 delay_access 2 allow lotsa_little_clients
4500 delay_access 2 deny all
4501 delay_access 3 allow authenticated_clients
4504 NAME: delay_parameters
4505 TYPE: delay_pool_rates
4510 This defines the parameters for a delay pool. Each delay pool has
4511 a number of "buckets" associated with it, as explained in the
4512 description of delay_class. For a class 1 delay pool, the syntax is:
4514 delay_parameters pool aggregate
4516 For a class 2 delay pool:
4518 delay_parameters pool aggregate individual
4520 For a class 3 delay pool:
4522 delay_parameters pool aggregate network individual
4524 For a class 4 delay pool:
4526 delay_parameters pool aggregate network individual user
4528 For a class 5 delay pool:
4530 delay_parameters pool tag
4532 The variables here are:
4534 pool a pool number - ie, a number between 1 and the
4535 number specified in delay_pools as used in
4538 aggregate the "delay parameters" for the aggregate bucket
4541 individual the "delay parameters" for the individual
4542 buckets (class 2, 3).
4544 network the "delay parameters" for the network buckets
4547 user the delay parameters for the user buckets
4550 tag the delay parameters for the tag buckets
4553 A pair of delay parameters is written restore/maximum, where restore is
4554 the number of bytes (not bits - modem and network speeds are usually
4555 quoted in bits) per second placed into the bucket, and maximum is the
4556 maximum number of bytes which can be in the bucket at any time.
4558 For example, if delay pool number 1 is a class 2 delay pool as in the
4559 above example, and is being used to strictly limit each host to 64kbps
4560 (plus overheads), with no overall limit, the line is:
4562 delay_parameters 1 -1/-1 8000/8000
4564 Note that the figure -1 is used to represent "unlimited".
4566 And, if delay pool number 2 is a class 3 delay pool as in the above
4567 example, and you want to limit it to a total of 256kbps (strict limit)
4568 with each 8-bit network permitted 64kbps (strict limit) and each
4569 individual host permitted 4800bps with a bucket maximum size of 64kb
4570 to permit a decent web page to be downloaded at a decent speed
4571 (if the network is not being limited due to overuse) but slow down
4572 large downloads more significantly:
4574 delay_parameters 2 32000/32000 8000/8000 600/8000
4576 There must be one delay_parameters line for each delay pool.
4578 Finally, for a class 4 delay pool as in the example - each user will
4579 be limited to 128Kb no matter how many workstations they are logged into.:
4581 delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000
4584 NAME: delay_initial_bucket_level
4585 COMMENT: (percent, 0-100)
4589 LOC: Config.Delay.initial
4591 The initial bucket percentage is used to determine how much is put
4592 in each bucket when squid starts, is reconfigured, or first notices
4593 a host accessing it (in class 2 and class 3, individual hosts and
4594 networks only have buckets associated with them once they have been
4599 WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS
4600 -----------------------------------------------------------------------------
4605 LOC: Config.Wccp.router
4609 Use this option to define your WCCP ``home'' router for
4612 wccp_router supports a single WCCP(v1) router
4614 wccp2_router supports multiple WCCPv2 routers
4616 only one of the two may be used at the same time and defines
4617 which version of WCCP to use.
4621 TYPE: IpAddress_list
4622 LOC: Config.Wccp2.router
4626 Use this option to define your WCCP ``home'' router for
4629 wccp_router supports a single WCCP(v1) router
4631 wccp2_router supports multiple WCCPv2 routers
4633 only one of the two may be used at the same time and defines
4634 which version of WCCP to use.
4639 LOC: Config.Wccp.version
4643 This directive is only relevant if you need to set up WCCP(v1)
4644 to some very old and end-of-life Cisco routers. In all other
4645 setups it must be left unset or at the default setting.
4646 It defines an internal version in the WCCP(v1) protocol,
4647 with version 4 being the officially documented protocol.
4649 According to some users, Cisco IOS 11.2 and earlier only
4650 support WCCP version 3. If you're using that or an earlier
4651 version of IOS, you may need to change this value to 3, otherwise
4652 do not specify this parameter.
4655 NAME: wccp2_rebuild_wait
4657 LOC: Config.Wccp2.rebuildwait
4661 If this is enabled Squid will wait for the cache dir rebuild to finish
4662 before sending the first wccp2 HereIAm packet
4665 NAME: wccp2_forwarding_method
4667 LOC: Config.Wccp2.forwarding_method
4671 WCCP2 allows the setting of forwarding methods between the
4672 router/switch and the cache. Valid values are as follows:
4674 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
4675 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
4677 Currently (as of IOS 12.4) cisco routers only support GRE.
4678 Cisco switches only support the L2 redirect assignment method.
4681 NAME: wccp2_return_method
4683 LOC: Config.Wccp2.return_method
4687 WCCP2 allows the setting of return methods between the
4688 router/switch and the cache for packets that the cache
4689 decides not to handle. Valid values are as follows:
4691 gre - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
4692 l2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
4694 Currently (as of IOS 12.4) cisco routers only support GRE.
4695 Cisco switches only support the L2 redirect assignment.
4697 If the "ip wccp redirect exclude in" command has been
4698 enabled on the cache interface, then it is still safe for
4699 the proxy server to use a l2 redirect method even if this
4700 option is set to GRE.
4703 NAME: wccp2_assignment_method
4705 LOC: Config.Wccp2.assignment_method
4709 WCCP2 allows the setting of methods to assign the WCCP hash
4710 Valid values are as follows:
4712 hash - Hash assignment
4713 mask - Mask assignment
4715 As a general rule, cisco routers support the hash assignment method
4716 and cisco switches support the mask assignment method.
4721 LOC: Config.Wccp2.info
4723 DEFAULT_IF_NONE: standard 0
4726 WCCP2 allows for multiple traffic services. There are two
4727 types: "standard" and "dynamic". The standard type defines
4728 one service id - http (id 0). The dynamic service ids can be from
4729 51 to 255 inclusive. In order to use a dynamic service id
4730 one must define the type of traffic to be redirected; this is done
4731 using the wccp2_service_info option.
4733 The "standard" type does not require a wccp2_service_info option,
4734 just specifying the service id will suffice.
4736 MD5 service authentication can be enabled by adding
4737 "password=<password>" to the end of this service declaration.
4741 wccp2_service standard 0 # for the 'web-cache' standard service
4742 wccp2_service dynamic 80 # a dynamic service type which will be
4743 # fleshed out with subsequent options.
4744 wccp2_service standard 0 password=foo
4747 NAME: wccp2_service_info
4748 TYPE: wccp2_service_info
4749 LOC: Config.Wccp2.info
4753 Dynamic WCCPv2 services require further information to define the
4754 traffic you wish to have diverted.
4758 wccp2_service_info <id> protocol=<protocol> flags=<flag>,<flag>..
4759 priority=<priority> ports=<port>,<port>..
4761 The relevant WCCPv2 flags:
4762 + src_ip_hash, dst_ip_hash
4763 + source_port_hash, dst_port_hash
4764 + src_ip_alt_hash, dst_ip_alt_hash
4765 + src_port_alt_hash, dst_port_alt_hash
4768 The port list can be one to eight entries.
4772 wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source
4773 priority=240 ports=80
4775 Note: the service id must have been defined by a previous
4776 'wccp2_service dynamic <id>' entry.
4781 LOC: Config.Wccp2.weight
4785 Each cache server gets assigned a set of the destination
4786 hash proportional to their weight.
4791 LOC: Config.Wccp.address
4798 LOC: Config.Wccp2.address
4802 Use this option if you require WCCP to use a specific
4805 The default behavior is to not bind to any specific address.
4809 PERSISTENT CONNECTION HANDLING
4810 -----------------------------------------------------------------------------
4812 Also see "pconn_timeout" in the TIMEOUTS section
4815 NAME: client_persistent_connections
4817 LOC: Config.onoff.client_pconns
4821 NAME: server_persistent_connections
4823 LOC: Config.onoff.server_pconns
4826 Persistent connection support for clients and servers. By
4827 default, Squid uses persistent connections (when allowed)
4828 with its clients and servers. You can use these options to
4829 disable persistent connections with clients and/or servers.
4832 NAME: persistent_connection_after_error
4834 LOC: Config.onoff.error_pconns
4837 With this directive the use of persistent connections after
4838 HTTP errors can be disabled. Useful if you have clients
4839 who fail to handle errors on persistent connections proper.
4842 NAME: detect_broken_pconn
4844 LOC: Config.onoff.detect_broken_server_pconns
4847 Some servers have been found to incorrectly signal the use
4848 of HTTP/1.0 persistent connections even on replies not
4849 compatible, causing significant delays. This server problem
4850 has mostly been seen on redirects.
4852 By enabling this directive Squid attempts to detect such
4853 broken replies and automatically assume the reply is finished
4854 after 10 seconds timeout.
4858 CACHE DIGEST OPTIONS
4859 -----------------------------------------------------------------------------
4862 NAME: digest_generation
4863 IFDEF: USE_CACHE_DIGESTS
4865 LOC: Config.onoff.digest_generation
4868 This controls whether the server will generate a Cache Digest
4869 of its contents. By default, Cache Digest generation is
4870 enabled if Squid is compiled with --enable-cache-digests defined.
4873 NAME: digest_bits_per_entry
4874 IFDEF: USE_CACHE_DIGESTS
4876 LOC: Config.digest.bits_per_entry
4879 This is the number of bits of the server's Cache Digest which
4880 will be associated with the Digest entry for a given HTTP
4881 Method and URL (public key) combination. The default is 5.
4884 NAME: digest_rebuild_period
4885 IFDEF: USE_CACHE_DIGESTS
4888 LOC: Config.digest.rebuild_period
4891 This is the wait time between Cache Digest rebuilds.
4894 NAME: digest_rewrite_period
4896 IFDEF: USE_CACHE_DIGESTS
4898 LOC: Config.digest.rewrite_period
4901 This is the wait time between Cache Digest writes to
4905 NAME: digest_swapout_chunk_size
4908 IFDEF: USE_CACHE_DIGESTS
4909 LOC: Config.digest.swapout_chunk_size
4912 This is the number of bytes of the Cache Digest to write to
4913 disk at a time. It defaults to 4096 bytes (4KB), the Squid
4917 NAME: digest_rebuild_chunk_percentage
4918 COMMENT: (percent, 0-100)
4919 IFDEF: USE_CACHE_DIGESTS
4921 LOC: Config.digest.rebuild_chunk_percentage
4924 This is the percentage of the Cache Digest to be scanned at a
4925 time. By default it is set to 10% of the Cache Digest.
4930 -----------------------------------------------------------------------------
4935 LOC: Config.Port.snmp
4939 The port number where Squid listens for SNMP requests. To enable
4940 SNMP support set this to a suitable port number. Port number
4941 3401 is often used for the Squid SNMP agent. By default it's
4942 set to "0" (disabled)
4950 LOC: Config.accessList.snmp
4952 DEFAULT_IF_NONE: deny all
4955 Allowing or denying access to the SNMP port.
4957 All access to the agent is denied by default.
4960 snmp_access allow|deny [!]aclname ...
4962 This clause only supports fast acl types.
4963 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
4965 snmp_access allow snmppublic localhost
4966 snmp_access deny all
4969 NAME: snmp_incoming_address
4971 LOC: Config.Addrs.snmp_incoming
4976 NAME: snmp_outgoing_address
4978 LOC: Config.Addrs.snmp_outgoing
4979 DEFAULT: 255.255.255.255
4982 Just like 'udp_incoming_address', but for the SNMP port.
4984 snmp_incoming_address is used for the SNMP socket receiving
4985 messages from SNMP agents.
4986 snmp_outgoing_address is used for SNMP packets returned to SNMP
4989 The default snmp_incoming_address (0.0.0.0) is to listen on all
4990 available network interfaces.
4992 If snmp_outgoing_address is set to 255.255.255.255 (the default)
4993 it will use the same socket as snmp_incoming_address. Only
4994 change this if you want to have SNMP replies sent using another
4995 address than where this Squid listens for SNMP queries.
4997 NOTE, snmp_incoming_address and snmp_outgoing_address can not have
4998 the same value since they both use port 3401.
5003 -----------------------------------------------------------------------------
5006 NAME: icp_port udp_port
5009 LOC: Config.Port.icp
5011 The port number where Squid sends and receives ICP queries to
5012 and from neighbor caches. The standard UDP port for ICP is 3130.
5013 Default is disabled (0).
5016 icp_port @DEFAULT_ICP_PORT@
5023 LOC: Config.Port.htcp
5025 The port number where Squid sends and receives HTCP queries to
5026 and from neighbor caches. To turn it on you want to set it to
5027 4827. By default it is set to "0" (disabled).
5033 NAME: log_icp_queries
5037 LOC: Config.onoff.log_udp
5039 If set, ICP queries are logged to access.log. You may wish
5040 do disable this if your ICP load is VERY high to speed things
5041 up or to simplify log analysis.
5044 NAME: udp_incoming_address
5046 LOC:Config.Addrs.udp_incoming
5049 udp_incoming_address is used for UDP packets received from other
5052 The default behavior is to not bind to any specific address.
5054 Only change this if you want to have all UDP queries received on
5055 a specific interface/address.
5057 NOTE: udp_incoming_address is used by the ICP, HTCP, and DNS
5058 modules. Altering it will affect all of them in the same manner.
5060 see also; udp_outgoing_address
5062 NOTE, udp_incoming_address and udp_outgoing_address can not
5063 have the same value since they both use the same port.
5066 NAME: udp_outgoing_address
5068 LOC: Config.Addrs.udp_outgoing
5069 DEFAULT: 255.255.255.255
5071 udp_outgoing_address is used for UDP packets sent out to other
5074 The default behavior is to not bind to any specific address.
5076 Instead it will use the same socket as udp_incoming_address.
5077 Only change this if you want to have UDP queries sent using another
5078 address than where this Squid listens for UDP queries from other
5081 NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS
5082 modules. Altering it will affect all of them in the same manner.
5084 see also; udp_incoming_address
5086 NOTE, udp_incoming_address and udp_outgoing_address can not
5087 have the same value since they both use the same port.
5094 LOC: Config.onoff.icp_hit_stale
5096 If you want to return ICP_HIT for stale cache objects, set this
5097 option to 'on'. If you have sibling relationships with caches
5098 in other administrative domains, this should be 'off'. If you only
5099 have sibling relationships with caches under your control,
5100 it is probably okay to set this to 'on'.
5101 If set to 'on', your siblings should use the option "allow-miss"
5102 on their cache_peer lines for connecting to you.
5105 NAME: minimum_direct_hops
5108 LOC: Config.minDirectHops
5110 If using the ICMP pinging stuff, do direct fetches for sites
5111 which are no more than this many hops away.
5114 NAME: minimum_direct_rtt
5117 LOC: Config.minDirectRtt
5119 If using the ICMP pinging stuff, do direct fetches for sites
5120 which are no more than this many rtt milliseconds away.
5126 LOC: Config.Netdb.low
5132 LOC: Config.Netdb.high
5134 The low and high water marks for the ICMP measurement
5135 database. These are counts, not percents. The defaults are
5136 900 and 1000. When the high water mark is reached, database
5137 entries will be deleted until the low mark is reached.
5140 NAME: netdb_ping_period
5142 LOC: Config.Netdb.period
5145 The minimum period for measuring a site. There will be at
5146 least this much delay between successive pings to the same
5147 network. The default is five minutes.
5154 LOC: Config.onoff.query_icmp
5156 If you want to ask your peers to include ICMP data in their ICP
5157 replies, enable this option.
5159 If your peer has configured Squid (during compilation) with
5160 '--enable-icmp' that peer will send ICMP pings to origin server
5161 sites of the URLs it receives. If you enable this option the
5162 ICP replies from that peer will include the ICMP data (if available).
5163 Then, when choosing a parent cache, Squid will choose the parent with
5164 the minimal RTT to the origin server. When this happens, the
5165 hierarchy field of the access.log will be
5166 "CLOSEST_PARENT_MISS". This option is off by default.
5169 NAME: test_reachability
5173 LOC: Config.onoff.test_reachability
5175 When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
5176 instead of ICP_MISS if the target host is NOT in the ICMP
5177 database, or has a zero RTT.
5180 NAME: icp_query_timeout
5184 LOC: Config.Timeout.icp_query
5186 Normally Squid will automatically determine an optimal ICP
5187 query timeout value based on the round-trip-time of recent ICP
5188 queries. If you want to override the value determined by
5189 Squid, set this 'icp_query_timeout' to a non-zero value. This
5190 value is specified in MILLISECONDS, so, to use a 2-second
5191 timeout (the old default), you would write:
5193 icp_query_timeout 2000
5196 NAME: maximum_icp_query_timeout
5200 LOC: Config.Timeout.icp_query_max
5202 Normally the ICP query timeout is determined dynamically. But
5203 sometimes it can lead to very large values (say 5 seconds).
5204 Use this option to put an upper limit on the dynamic timeout
5205 value. Do NOT use this option to always use a fixed (instead
5206 of a dynamic) timeout value. To set a fixed timeout see the
5207 'icp_query_timeout' directive.
5210 NAME: minimum_icp_query_timeout
5214 LOC: Config.Timeout.icp_query_min
5216 Normally the ICP query timeout is determined dynamically. But
5217 sometimes it can lead to very small timeouts, even lower than
5218 the normal latency variance on your link due to traffic.
5219 Use this option to put an lower limit on the dynamic timeout
5220 value. Do NOT use this option to always use a fixed (instead
5221 of a dynamic) timeout value. To set a fixed timeout see the
5222 'icp_query_timeout' directive.
5225 NAME: background_ping_rate
5229 LOC: Config.backgroundPingRate
5231 Controls how often the ICP pings are sent to siblings that
5232 have background-ping set.
5236 MULTICAST ICP OPTIONS
5237 -----------------------------------------------------------------------------
5242 LOC: Config.mcast_group_list
5245 This tag specifies a list of multicast groups which your server
5246 should join to receive multicasted ICP queries.
5248 NOTE! Be very careful what you put here! Be sure you
5249 understand the difference between an ICP _query_ and an ICP
5250 _reply_. This option is to be set only if you want to RECEIVE
5251 multicast queries. Do NOT set this option to SEND multicast
5252 ICP (use cache_peer for that). ICP replies are always sent via
5253 unicast, so this option does not affect whether or not you will
5254 receive replies from multicast group members.
5256 You must be very careful to NOT use a multicast address which
5257 is already in use by another group of caches.
5259 If you are unsure about multicast, please read the Multicast
5260 chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
5262 Usage: mcast_groups 239.128.16.128 224.0.1.20
5264 By default, Squid doesn't listen on any multicast groups.
5267 NAME: mcast_miss_addr
5268 IFDEF: MULTICAST_MISS_STREAM
5270 LOC: Config.mcast_miss.addr
5271 DEFAULT: 255.255.255.255
5273 If you enable this option, every "cache miss" URL will
5274 be sent out on the specified multicast address.
5276 Do not enable this option unless you are are absolutely
5277 certain you understand what you are doing.
5280 NAME: mcast_miss_ttl
5281 IFDEF: MULTICAST_MISS_STREAM
5283 LOC: Config.mcast_miss.ttl
5286 This is the time-to-live value for packets multicasted
5287 when multicasting off cache miss URLs is enabled. By
5288 default this is set to 'site scope', i.e. 16.
5291 NAME: mcast_miss_port
5292 IFDEF: MULTICAST_MISS_STREAM
5294 LOC: Config.mcast_miss.port
5297 This is the port number to be used in conjunction with
5301 NAME: mcast_miss_encode_key
5302 IFDEF: MULTICAST_MISS_STREAM
5304 LOC: Config.mcast_miss.encode_key
5305 DEFAULT: XXXXXXXXXXXXXXXX
5307 The URLs that are sent in the multicast miss stream are
5308 encrypted. This is the encryption key.
5311 NAME: mcast_icp_query_timeout
5315 LOC: Config.Timeout.mcast_icp_query
5317 For multicast peers, Squid regularly sends out ICP "probes" to
5318 count how many other peers are listening on the given multicast
5319 address. This value specifies how long Squid should wait to
5320 count all the replies. The default is 2000 msec, or 2
5325 INTERNAL ICON OPTIONS
5326 -----------------------------------------------------------------------------
5329 NAME: icon_directory
5331 LOC: Config.icons.directory
5332 DEFAULT: @DEFAULT_ICON_DIR@
5334 Where the icons are stored. These are normally kept in
5338 NAME: global_internal_static
5340 LOC: Config.onoff.global_internal_static
5343 This directive controls is Squid should intercept all requests for
5344 /squid-internal-static/ no matter which host the URL is requesting
5345 (default on setting), or if nothing special should be done for
5346 such URLs (off setting). The purpose of this directive is to make
5347 icons etc work better in complex cache hierarchies where it may
5348 not always be possible for all corners in the cache mesh to reach
5349 the server generating a directory listing.
5352 NAME: short_icon_urls
5354 LOC: Config.icons.use_short_names
5357 If this is enabled Squid will use short URLs for icons.
5358 If disabled it will revert to the old behavior of including
5359 it's own name and port in the URL.
5361 If you run a complex cache hierarchy with a mix of Squid and
5362 other proxies you may need to disable this directive.
5367 -----------------------------------------------------------------------------
5370 NAME: error_directory
5372 LOC: Config.errorDirectory
5375 If you wish to create your own versions of the default
5376 error files to customize them to suit your company copy
5377 the error/template files to another directory and point
5380 WARNING: This option will disable multi-language support
5381 on error pages if used.
5383 The squid developers are interested in making squid available in
5384 a wide variety of languages. If you are making translations for a
5385 language that Squid does not currently provide please consider
5386 contributing your translation back to the project.
5387 http://wiki.squid-cache.org/Translations
5389 The squid developers working on translations are happy to supply drop-in
5390 translated error files in exchange for any new language contributions.
5393 NAME: error_default_language
5394 IFDEF: USE_ERR_LOCALES
5396 LOC: Config.errorDefaultLanguage
5399 Set the default language which squid will send error pages in
5400 if no existing translation matches the clients language
5403 If unset (default) generic English will be used.
5405 The squid developers are interested in making squid available in
5406 a wide variety of languages. If you are interested in making
5407 translations for any language see the squid wiki for details.
5408 http://wiki.squid-cache.org/Translations
5411 NAME: error_log_languages
5412 IFDEF: USE_ERR_LOCALES
5414 LOC: Config.errorLogMissingLanguages
5417 Log to cache.log what languages users are attempting to
5418 auto-negotiate for translations.
5420 Successful negotiations are not logged. Only failures
5421 have meaning to indicate that Squid may need an upgrade
5422 of its error page translations.
5425 NAME: err_page_stylesheet
5427 LOC: Config.errorStylesheet
5428 DEFAULT: @DEFAULT_CONFIG_DIR@/errorpage.css
5430 CSS Stylesheet to pattern the display of Squid default error pages.
5432 For information on CSS see http://www.w3.org/Style/CSS/
5437 LOC: Config.errHtmlText
5440 HTML text to include in error messages. Make this a "mailto"
5441 URL to your admin address, or maybe just a link to your
5442 organizations Web page.
5444 To include this in your error messages, you must rewrite
5445 the error template files (found in the "errors" directory).
5446 Wherever you want the 'err_html_text' line to appear,
5447 insert a %L tag in the error template file.
5450 NAME: email_err_data
5453 LOC: Config.onoff.emailErrData
5456 If enabled, information about the occurred error will be
5457 included in the mailto links of the ERR pages (if %W is set)
5458 so that the email body contains the data.
5459 Syntax is <A HREF="mailto:%w%W">%w</A>
5464 LOC: Config.denyInfoList
5467 Usage: deny_info err_page_name acl
5468 or deny_info http://... acl
5469 or deny_info TCP_RESET acl
5471 This can be used to return a ERR_ page for requests which
5472 do not pass the 'http_access' rules. Squid remembers the last
5473 acl it evaluated in http_access, and if a 'deny_info' line exists
5474 for that ACL Squid returns a corresponding error page.
5476 The acl is typically the last acl on the http_access deny line which
5477 denied access. The exceptions to this rule are:
5478 - When Squid needs to request authentication credentials. It's then
5479 the first authentication related acl encountered
5480 - When none of the http_access lines matches. It's then the last
5481 acl processed on the last http_access line.
5483 NP: If providing your own custom error pages with error_directory
5484 you may also specify them by your custom file name:
5485 Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
5487 Alternatively you can tell Squid to reset the TCP connection
5488 by specifying TCP_RESET.
5490 Or you can specify an error URL or URL pattern. The browsers will
5491 get redirected (302) to the specified URL after formattgin tags have
5495 %a - username (if available. Password NOT included)
5498 %E - Error description
5500 %H - Request domain name
5501 %i - Client IP Address
5503 %o - Message result from external ACL helper
5504 %p - Request Port number
5505 %P - Request Protocol name
5506 %R - Request URL path
5507 %T - Timestamp in RFC 1123 format
5508 %U - Full canonical URL from client
5509 (HTTPS URLs terminate with *)
5510 %u - Full canonical URL from client
5511 %w - Admin email from squid.conf
5512 %% - Literal percent (%) code
5517 OPTIONS INFLUENCING REQUEST FORWARDING
5518 -----------------------------------------------------------------------------
5521 NAME: nonhierarchical_direct
5523 LOC: Config.onoff.nonhierarchical_direct
5526 By default, Squid will send any non-hierarchical requests
5527 (matching hierarchy_stoplist or not cacheable request type) direct
5530 If you set this to off, Squid will prefer to send these
5531 requests to parents.
5533 Note that in most configurations, by turning this off you will only
5534 add latency to these request without any improvement in global hit
5537 If you are inside an firewall see never_direct instead of
5543 LOC: Config.onoff.prefer_direct
5546 Normally Squid tries to use parents for most requests. If you for some
5547 reason like it to first try going direct and only use a parent if
5548 going direct fails set this to on.
5550 By combining nonhierarchical_direct off and prefer_direct on you
5551 can set up Squid to use a parent as a backup path if going direct
5554 Note: If you want Squid to use parents for all requests see
5555 the never_direct directive. prefer_direct only modifies how Squid
5556 acts on cacheable requests.
5561 LOC: Config.accessList.AlwaysDirect
5564 Usage: always_direct allow|deny [!]aclname ...
5566 Here you can use ACL elements to specify requests which should
5567 ALWAYS be forwarded by Squid to the origin servers without using
5568 any peers. For example, to always directly forward requests for
5569 local servers ignoring any parents or siblings you may have use
5572 acl local-servers dstdomain my.domain.net
5573 always_direct allow local-servers
5575 To always forward FTP requests directly, use
5578 always_direct allow FTP
5580 NOTE: There is a similar, but opposite option named
5581 'never_direct'. You need to be aware that "always_direct deny
5582 foo" is NOT the same thing as "never_direct allow foo". You
5583 may need to use a deny rule to exclude a more-specific case of
5584 some other rule. Example:
5586 acl local-external dstdomain external.foo.net
5587 acl local-servers dstdomain .foo.net
5588 always_direct deny local-external
5589 always_direct allow local-servers
5591 NOTE: If your goal is to make the client forward the request
5592 directly to the origin server bypassing Squid then this needs
5593 to be done in the client configuration. Squid configuration
5594 can only tell Squid how Squid should fetch the object.
5596 NOTE: This directive is not related to caching. The replies
5597 is cached as usual even if you use always_direct. To not cache
5598 the replies see the 'cache' directive.
5600 This clause supports both fast and slow acl types.
5601 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5606 LOC: Config.accessList.NeverDirect
5609 Usage: never_direct allow|deny [!]aclname ...
5611 never_direct is the opposite of always_direct. Please read
5612 the description for always_direct if you have not already.
5614 With 'never_direct' you can use ACL elements to specify
5615 requests which should NEVER be forwarded directly to origin
5616 servers. For example, to force the use of a proxy for all
5617 requests, except those in your local domain use something like:
5619 acl local-servers dstdomain .foo.net
5620 never_direct deny local-servers
5621 never_direct allow all
5623 or if Squid is inside a firewall and there are local intranet
5624 servers inside the firewall use something like:
5626 acl local-intranet dstdomain .foo.net
5627 acl local-external dstdomain external.foo.net
5628 always_direct deny local-external
5629 always_direct allow local-intranet
5630 never_direct allow all
5632 This clause supports both fast and slow acl types.
5633 See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
5637 ADVANCED NETWORKING OPTIONS
5638 -----------------------------------------------------------------------------
5641 NAME: incoming_icp_average
5644 LOC: Config.comm_incoming.icp_average
5647 NAME: incoming_http_average
5650 LOC: Config.comm_incoming.http_average
5653 NAME: incoming_dns_average
5656 LOC: Config.comm_incoming.dns_average
5659 NAME: min_icp_poll_cnt
5662 LOC: Config.comm_incoming.icp_min_poll
5665 NAME: min_dns_poll_cnt
5668 LOC: Config.comm_incoming.dns_min_poll
5671 NAME: min_http_poll_cnt
5674 LOC: Config.comm_incoming.http_min_poll
5676 Heavy voodoo here. I can't even believe you are reading this.
5677 Are you crazy? Don't even think about adjusting these unless
5678 you understand the algorithms in comm_select.c first!
5684 LOC: Config.accept_filter
5688 The name of an accept(2) filter to install on Squid's
5689 listen socket(s). This feature is perhaps specific to
5690 FreeBSD and requires support in the kernel.
5692 The 'httpready' filter delays delivering new connections
5693 to Squid until a full HTTP request has been received.
5694 See the accf_http(9) man page for details.
5696 The 'dataready' filter delays delivering new connections
5697 to Squid until there is some data to process.
5698 See the accf_dataready(9) man page for details.
5702 The 'data' filter delays delivering of new connections
5703 to Squid until there is some data to process by TCP_ACCEPT_DEFER.
5704 You may optionally specify a number of seconds to wait by
5705 'data=N' where N is the number of seconds. Defaults to 30
5706 if not specified. See the tcp(7) man page for details.
5709 accept_filter httpready
5714 NAME: client_ip_max_connections
5716 LOC: Config.client_ip_max_connections
5719 Set an absolute limit on the number of connections a single
5720 client IP can use. Any more than this and Squid will begin to drop
5721 new connections from the client until it closes some links.
5723 Note that this is a global limit. It affects all HTTP, HTCP, Gopher and FTP
5724 connections from the client. For finer control use the ACL access controls.
5726 Requires client_db to be enabled (the default).
5728 WARNING: This may noticably slow down traffic received via external proxies
5729 or NAT devices and cause them to rebound error messages back to their clients.
5732 NAME: tcp_recv_bufsize
5736 LOC: Config.tcpRcvBufsz
5738 Size of receive buffer to set for TCP sockets. Probably just
5739 as easy to change your kernel's default. Set to zero to use
5740 the default buffer size.
5745 -----------------------------------------------------------------------------
5752 LOC: Adaptation::Icap::TheConfig.onoff
5755 If you want to enable the ICAP module support, set this to on.
5758 NAME: icap_connect_timeout
5761 LOC: Adaptation::Icap::TheConfig.connect_timeout_raw
5764 This parameter specifies how long to wait for the TCP connect to
5765 the requested ICAP server to complete before giving up and either
5766 terminating the HTTP transaction or bypassing the failure.
5768 The default for optional services is peer_connect_timeout.
5769 The default for essential services is connect_timeout.
5770 If this option is explicitly set, its value applies to all services.
5773 NAME: icap_io_timeout
5777 LOC: Adaptation::Icap::TheConfig.io_timeout_raw
5780 This parameter specifies how long to wait for an I/O activity on
5781 an established, active ICAP connection before giving up and
5782 either terminating the HTTP transaction or bypassing the
5785 The default is read_timeout.
5788 NAME: icap_service_failure_limit
5789 COMMENT: limit [in memory-depth time-units]
5790 TYPE: icap_service_failure_limit
5792 LOC: Adaptation::Icap::TheConfig
5795 The limit specifies the number of failures that Squid tolerates
5796 when establishing a new TCP connection with an ICAP service. If
5797 the number of failures exceeds the limit, the ICAP service is
5798 not used for new ICAP requests until it is time to refresh its
5801 A negative value disables the limit. Without the limit, an ICAP
5802 service will not be considered down due to connectivity failures
5803 between ICAP OPTIONS requests.
5805 Squid forgets ICAP service failures older than the specified
5806 value of memory-depth. The memory fading algorithm
5807 is approximate because Squid does not remember individual
5808 errors but groups them instead, splitting the option
5809 value into ten time slots of equal length.
5811 When memory-depth is 0 and by default this option has no
5812 effect on service failure expiration.
5814 Squid always forgets failures when updating service settings
5815 using an ICAP OPTIONS transaction, regardless of this option
5819 # suspend service usage after 10 failures in 5 seconds:
5820 icap_service_failure_limit 10 in 5 seconds
5823 NAME: icap_service_revival_delay
5826 LOC: Adaptation::Icap::TheConfig.service_revival_delay
5829 The delay specifies the number of seconds to wait after an ICAP
5830 OPTIONS request failure before requesting the options again. The
5831 failed ICAP service is considered "down" until fresh OPTIONS are
5834 The actual delay cannot be smaller than the hardcoded minimum
5835 delay of 30 seconds.
5838 NAME: icap_preview_enable
5842 LOC: Adaptation::Icap::TheConfig.preview_enable
5845 The ICAP Preview feature allows the ICAP server to handle the
5846 HTTP message by looking only at the beginning of the message body
5847 or even without receiving the body at all. In some environments,
5848 previews greatly speedup ICAP processing.
5850 During an ICAP OPTIONS transaction, the server may tell Squid what
5851 HTTP messages should be previewed and how big the preview should be.
5852 Squid will not use Preview if the server did not request one.
5854 To disable ICAP Preview for all ICAP services, regardless of
5855 individual ICAP server OPTIONS responses, set this option to "off".
5857 icap_preview_enable off
5860 NAME: icap_preview_size
5863 LOC: Adaptation::Icap::TheConfig.preview_size
5866 The default size of preview data to be sent to the ICAP server.
5867 -1 means no preview. This value might be overwritten on a per server
5868 basis by OPTIONS requests.
5871 NAME: icap_default_options_ttl
5874 LOC: Adaptation::Icap::TheConfig.default_options_ttl
5877 The default TTL value for ICAP OPTIONS responses that don't have
5878 an Options-TTL header.
5881 NAME: icap_persistent_connections
5885 LOC: Adaptation::Icap::TheConfig.reuse_connections
5888 Whether or not Squid should use persistent connections to
5892 NAME: icap_send_client_ip
5896 LOC: Adaptation::Icap::TheConfig.send_client_ip
5899 This adds the header "X-Client-IP" to ICAP requests.
5902 NAME: icap_send_client_username
5906 LOC: Adaptation::Icap::TheConfig.send_client_username
5909 This sends authenticated HTTP client username (if available) to
5910 the ICAP service. The username value is encoded based on the
5911 icap_client_username_encode option and is sent using the header
5912 specified by the icap_client_username_header option.
5915 NAME: icap_client_username_header
5918 LOC: Adaptation::Icap::TheConfig.client_username_header
5919 DEFAULT: X-Client-Username
5921 ICAP request header name to use for send_client_username.
5924 NAME: icap_client_username_encode
5928 LOC: Adaptation::Icap::TheConfig.client_username_encode
5931 Whether to base64 encode the authenticated client username.
5935 TYPE: icap_service_type
5937 LOC: Adaptation::Icap::TheConfig
5940 Defines a single ICAP service using the following format:
5942 icap_service service_name vectoring_point [options] service_url
5945 an opaque identifier which must be unique in squid.conf
5947 vectoring_point: reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
5948 This specifies at which point of transaction processing the
5949 ICAP service should be activated. *_postcache vectoring points
5950 are not yet supported.
5952 service_url: icap://servername:port/servicepath
5953 ICAP server and service location.
5955 ICAP does not allow a single service to handle both REQMOD and RESPMOD
5956 transactions. Squid does not enforce that requirement. You can specify
5957 services with the same service_url and different vectoring_points. You
5958 can even specify multiple identical services as long as their
5959 service_names differ.
5962 Service options are separated by white space. ICAP services support
5963 the following name=value options:
5966 If set to 'on' or '1', the ICAP service is treated as
5967 optional. If the service cannot be reached or malfunctions,
5968 Squid will try to ignore any errors and process the message as
5969 if the service was not enabled. No all ICAP errors can be
5970 bypassed. If set to 0, the ICAP service is treated as
5971 essential and all ICAP errors will result in an error page
5972 returned to the HTTP client.
5974 Bypass is off by default: services are treated as essential.
5977 If set to 'on' or '1', the ICAP service is allowed to
5978 dynamically change the current message adaptation plan by
5979 returning a chain of services to be used next. The services
5980 are specified using the X-Next-Services ICAP response header
5981 value, formatted as a comma-separated list of service names.
5982 Each named service should be configured in squid.conf and
5983 should have the same method and vectoring point as the current
5984 ICAP transaction. Services violating these rules are ignored.
5985 An empty X-Next-Services value results in an empty plan which
5986 ends the current adaptation.
5988 Routing is not allowed by default: the ICAP X-Next-Services
5989 response header is ignored.
5991 Older icap_service format without optional named parameters is
5992 deprecated but supported for backward compatibility.
5995 icap_service svcBlocker reqmod_precache bypass=0 icap://icap1.mydomain.net:1344/reqmod
5996 icap_service svcLogger reqmod_precache routing=on icap://icap2.mydomain.net:1344/respmod
6000 TYPE: icap_class_type
6005 This deprecated option was documented to define an ICAP service
6006 chain, even though it actually defined a set of similar, redundant
6007 services, and the chains were not supported.
6009 To define a set of redundant services, please use the
6010 adaptation_service_set directive. For service chains, use
6011 adaptation_service_chain.
6015 TYPE: icap_access_type
6020 This option is deprecated. Please use adaptation_access, which
6021 has the same ICAP functionality, but comes with better
6022 documentation, and eCAP support.
6027 -----------------------------------------------------------------------------
6034 LOC: Adaptation::Ecap::TheConfig.onoff
6037 Controls whether eCAP support is enabled.
6041 TYPE: ecap_service_type
6043 LOC: Adaptation::Ecap::TheConfig
6046 Defines a single eCAP service
6048 ecap_service servicename vectoring_point bypass service_url
6050 vectoring_point = reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
6051 This specifies at which point of transaction processing the
6052 eCAP service should be activated. *_postcache vectoring points
6053 are not yet supported.
6055 If set to 1, the eCAP service is treated as optional. If the
6056 service cannot be reached or malfunctions, Squid will try to
6057 ignore any errors and process the message as if the service
6058 was not enabled. No all eCAP errors can be bypassed.
6059 If set to 0, the eCAP service is treated as essential and all
6060 eCAP errors will result in an error page returned to the
6062 service_url = ecap://vendor/service_name?custom&cgi=style¶meters=optional
6065 ecap_service service_1 reqmod_precache 0 ecap://filters-R-us/leakDetector?on_error=block
6066 ecap_service service_2 respmod_precache 1 icap://filters-R-us/virusFilter?config=/etc/vf.cfg
6069 NAME: loadable_modules
6071 IFDEF: USE_LOADABLE_MODULES
6072 LOC: Config.loadable_module_names
6075 Instructs Squid to load the specified dynamic module(s) or activate
6076 preloaded module(s).
6078 loadable_modules @DEFAULT_PREFIX@/lib/MinimalAdapter.so
6082 MESSAGE ADAPTATION OPTIONS
6083 -----------------------------------------------------------------------------
6086 NAME: adaptation_service_set
6087 TYPE: adaptation_service_set_type
6088 IFDEF: USE_ADAPTATION
6093 Configures an ordered set of similar, redundant services. This is
6094 useful when hot standby or backup adaptation servers are available.
6096 adaptation_service_set set_name service_name1 service_name2 ...
6098 The named services are used in the set declaration order. The first
6099 applicable adaptation service from the set is used first. The next
6100 applicable service is tried if and only if the transaction with the
6101 previous service fails and the message waiting to be adapted is still
6104 When adaptation starts, broken services are ignored as if they were
6105 not a part of the set. A broken service is a down optional service.
6107 The services in a set must be attached to the same vectoring point
6108 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
6110 If all services in a set are optional then adaptation failures are
6111 bypassable. If all services in the set are essential, then a
6112 transaction failure with one service may still be retried using
6113 another service from the set, but when all services fail, the master
6114 transaction fails as well.
6116 A set may contain a mix of optional and essential services, but that
6117 is likely to lead to surprising results because broken services become
6118 ignored (see above), making previously bypassable failures fatal.
6119 Technically, it is the bypassability of the last failed service that
6122 See also: adaptation_access adaptation_service_chain
6125 adaptation_service_set svcBlocker urlFilterPrimary urlFilterBackup
6126 adaptation service_set svcLogger loggerLocal loggerRemote
6129 NAME: adaptation_service_chain
6130 TYPE: adaptation_service_chain_type
6131 IFDEF: USE_ADAPTATION
6136 Configures a list of complementary services that will be applied
6137 one-by-one, forming an adaptation chain or pipeline. This is useful
6138 when Squid must perform different adaptations on the same message.
6140 adaptation_service_chain chain_name service_name1 svc_name2 ...
6142 The named services are used in the chain declaration order. The first
6143 applicable adaptation service from the chain is used first. The next
6144 applicable service is applied to the successful adaptation results of
6145 the previous service in the chain.
6147 When adaptation starts, broken services are ignored as if they were
6148 not a part of the chain. A broken service is a down optional service.
6150 Request satisfaction terminates the adaptation chain because Squid
6151 does not currently allow declaration of RESPMOD services at the
6152 "reqmod_precache" vectoring point (see icap_service or ecap_service).
6154 The services in a chain must be attached to the same vectoring point
6155 (e.g., pre-cache) and use the same adaptation method (e.g., REQMOD).
6157 A chain may contain a mix of optional and essential services. If an
6158 essential adaptation fails (or the failure cannot be bypassed for
6159 other reasons), the master transaction fails. Otherwise, the failure
6160 is bypassed as if the failed adaptation service was not in the chain.
6162 See also: adaptation_access adaptation_service_set
6165 adaptation_service_chain svcRequest requestLogger urlFilter leakDetector
6168 NAME: adaptation_access
6169 TYPE: adaptation_access_type
6170 IFDEF: USE_ADAPTATION
6174 Sends an HTTP transaction to an ICAP or eCAP adaptation service.
6176 adaptation_access service_name allow|deny [!]aclname...
6177 adaptation_access set_name allow|deny [!]aclname...
6179 At each supported vectoring point, the adaptation_access
6180 statements are processed in the order they appear in this
6181 configuration file. Statements pointing to the following services
6182 are ignored (i.e., skipped without checking their ACL):
6184 - services serving different vectoring points
6185 - "broken-but-bypassable" services
6186 - "up" services configured to ignore such transactions
6187 (e.g., based on the ICAP Transfer-Ignore header).
6189 When a set_name is used, all services in the set are checked
6190 using the same rules, to find the first applicable one. See
6191 adaptation_service_set for details.
6193 If an access list is checked and there is a match, the
6194 processing stops: For an "allow" rule, the corresponding
6195 adaptation service is used for the transaction. For a "deny"
6196 rule, no adaptation service is activated.
6198 It is currently not possible to apply more than one adaptation
6199 service at the same vectoring point to the same HTTP transaction.
6201 See also: icap_service and ecap_service
6204 adaptation_access service_1 allow all
6207 NAME: adaptation_service_iteration_limit
6209 IFDEF: USE_ADAPTATION
6210 LOC: Adaptation::Config::service_iteration_limit
6213 Limits the number of iterations allowed when applying adaptation
6214 services to a message. If your longest adaptation set or chain
6215 may have more than 16 services, increase the limit beyond its
6216 default value of 16. If detecting infinite iteration loops sooner
6217 is critical, make the iteration limit match the actual number
6218 of services in your longest adaptation set or chain.
6220 Infinite adaptation loops are most likely with routing services.
6222 See also: icap_service routing=1
6225 NAME: adaptation_masterx_shared_names
6227 IFDEF: USE_ADAPTATION
6228 LOC: Adaptation::Config::masterx_shared_name
6231 For each master transaction (i.e., the HTTP request and response
6232 sequence, including all related ICAP and eCAP exchanges), Squid
6233 maintains a table of metadata. The table entries are (name, value)
6234 pairs shared among eCAP and ICAP exchanges. The table is destroyed
6235 with the master transaction.
6237 This option specifies the table entry names that Squid must accept
6238 from and forward to the adaptation transactions.
6240 An ICAP REQMOD or RESPMOD transaction may set an entry in the
6241 shared table by returning an ICAP header field with a name
6242 specified in adaptation_masterx_shared_names. Squid will store
6243 and forward that ICAP header field to subsequent ICAP
6244 transactions within the same master transaction scope.
6246 Only one shared entry name is supported at this time.
6249 # share authentication information among ICAP services
6250 adaptation_masterx_shared_names X-Subscriber-ID
6256 LOC: Adaptation::Icap::TheConfig.repeat
6258 DEFAULT_IF_NONE: deny all
6260 This ACL determines which retriable ICAP transactions are
6261 retried. Transactions that received a complete ICAP response
6262 and did not have to consume or produce HTTP bodies to receive
6263 that response are usually retriable.
6265 icap_retry allow|deny [!]aclname ...
6267 Squid automatically retries some ICAP I/O timeouts and errors
6268 due to persistent connection race conditions.
6270 See also: icap_retry_limit
6273 NAME: icap_retry_limit
6276 LOC: Adaptation::Icap::TheConfig.repeat_limit
6279 Limits the number of retries allowed. When set to zero (default),
6280 no retries are allowed.
6282 Communication errors due to persistent connection race
6283 conditions are unavoidable, automatically retried, and do not
6284 count against this limit.
6286 See also: icap_retry
6292 -----------------------------------------------------------------------------
6295 NAME: check_hostnames
6298 LOC: Config.onoff.check_hostnames
6300 For security and stability reasons Squid can check
6301 hostnames for Internet standard RFC compliance. If you want
6302 Squid to perform these checks turn this directive on.
6305 NAME: allow_underscore
6308 LOC: Config.onoff.allow_underscore
6310 Underscore characters is not strictly allowed in Internet hostnames
6311 but nevertheless used by many sites. Set this to off if you want
6312 Squid to be strict about the standard.
6313 This check is performed only when check_hostnames is set to on.
6316 NAME: cache_dns_program
6318 IFDEF: USE_DNSSERVERS
6319 DEFAULT: @DEFAULT_DNSSERVER@
6320 LOC: Config.Program.dnsserver
6322 Specify the location of the executable for dnslookup process.
6326 TYPE: HelperChildConfig
6327 IFDEF: USE_DNSSERVERS
6328 DEFAULT: 32 startup=1 idle=1
6329 LOC: Config.dnsChildren
6331 The maximum number of processes spawn to service DNS name lookups.
6332 If you limit it too few Squid will have to wait for them to process
6333 a backlog of requests, slowing it down. If you allow too many they
6334 will use RAM and other system resources noticably.
6335 The maximum this may be safely set to is 32.
6337 The startup= and idle= options allow some measure of skew in your
6342 Sets a minimum of how many processes are to be spawned when Squid
6343 starts or reconfigures. When set to zero the first request will
6344 cause spawning of the first child process to handle it.
6346 Starting too few will cause an initial slowdown in traffic as Squid
6347 attempts to simultaneously spawn enough processes to cope.
6351 Sets a minimum of how many processes Squid is to try and keep available
6352 at all times. When traffic begins to rise above what the existing
6353 processes can handle this many more will be spawned up to the maximum
6354 configured. A minimum setting of 1 is required.
6357 NAME: dns_retransmit_interval
6360 LOC: Config.Timeout.idns_retransmit
6361 IFDEF: !USE_DNSSERVERS
6363 Initial retransmit interval for DNS queries. The interval is
6364 doubled each time all configured DNS servers have been tried.
6370 LOC: Config.Timeout.idns_query
6371 IFDEF: !USE_DNSSERVERS
6373 DNS Query timeout. If no response is received to a DNS query
6374 within this time all DNS servers for the queried domain
6375 are assumed to be unavailable.
6382 LOC: Config.onoff.res_defnames
6384 Normally the RES_DEFNAMES resolver option is disabled
6385 (see res_init(3)). This prevents caches in a hierarchy
6386 from interpreting single-component hostnames locally. To allow
6387 Squid to handle single-component names, enable this option.
6390 NAME: dns_nameservers
6393 LOC: Config.dns_nameservers
6395 Use this if you want to specify a list of DNS name servers
6396 (IP addresses) to use instead of those given in your
6397 /etc/resolv.conf file.
6398 On Windows platforms, if no value is specified here or in
6399 the /etc/resolv.conf file, the list of DNS name servers are
6400 taken from the Windows registry, both static and dynamic DHCP
6401 configurations are supported.
6403 Example: dns_nameservers 10.0.0.1 192.172.0.4
6408 DEFAULT: @DEFAULT_HOSTS@
6409 LOC: Config.etcHostsPath
6411 Location of the host-local IP name-address associations
6412 database. Most Operating Systems have such a file on different
6414 - Un*X & Linux: /etc/hosts
6415 - Windows NT/2000: %SystemRoot%\system32\drivers\etc\hosts
6416 (%SystemRoot% value install default is c:\winnt)
6417 - Windows XP/2003: %SystemRoot%\system32\drivers\etc\hosts
6418 (%SystemRoot% value install default is c:\windows)
6419 - Windows 9x/Me: %windir%\hosts
6420 (%windir% value is usually c:\windows)
6421 - Cygwin: /etc/hosts
6423 The file contains newline-separated definitions, in the
6424 form ip_address_in_dotted_form name [name ...] names are
6425 whitespace-separated. Lines beginning with an hash (#)
6426 character are comments.
6428 The file is checked at startup and upon configuration.
6429 If set to 'none', it won't be checked.
6430 If append_domain is used, that domain will be added to
6431 domain-local (i.e. not containing any dot character) host
6437 LOC: Config.appendDomain
6440 Appends local domain name to hostnames without any dots in
6441 them. append_domain must begin with a period.
6443 Be warned there are now Internet names with no dots in
6444 them using only top-domain names, so setting this may
6445 cause some Internet sites to become unavailable.
6448 append_domain .yourdomain.com
6451 NAME: ignore_unknown_nameservers
6453 LOC: Config.onoff.ignore_unknown_nameservers
6456 By default Squid checks that DNS responses are received
6457 from the same IP addresses they are sent to. If they
6458 don't match, Squid ignores the response and writes a warning
6459 message to cache.log. You can allow responses from unknown
6460 nameservers by setting this option to 'off'.
6463 NAME: dns_v4_fallback
6466 LOC: Config.onoff.dns_require_A
6468 Standard practice with DNS is to lookup either A or AAAA records
6469 and use the results if it succeeds. Only looking up the other if
6470 the first attempt fails or otherwise produces no results.
6472 That policy however will cause squid to produce error pages for some
6473 servers that advertise AAAA but are unreachable over IPv6.
6475 If this is ON squid will always lookup both AAAA and A, using both.
6476 If this is OFF squid will lookup AAAA and only try A if none found.
6478 WARNING: There are some possibly unwanted side-effects with this on:
6479 *) Doubles the load placed by squid on the DNS network.
6480 *) May negatively impact connection delay times.
6484 COMMENT: (number of entries)
6487 LOC: Config.ipcache.size
6494 LOC: Config.ipcache.low
6501 LOC: Config.ipcache.high
6503 The size, low-, and high-water marks for the IP cache.
6506 NAME: fqdncache_size
6507 COMMENT: (number of entries)
6510 LOC: Config.fqdncache.size
6512 Maximum number of FQDN cache entries.
6517 -----------------------------------------------------------------------------
6524 LOC: Config.onoff.mem_pools
6526 If set, Squid will keep pools of allocated (but unused) memory
6527 available for future use. If memory is a premium on your
6528 system and you believe your malloc library outperforms Squid
6529 routines, disable this.
6532 NAME: memory_pools_limit
6536 LOC: Config.MemPools.limit
6538 Used only with memory_pools on:
6539 memory_pools_limit 50 MB
6541 If set to a non-zero value, Squid will keep at most the specified
6542 limit of allocated (but unused) memory in memory pools. All free()
6543 requests that exceed this limit will be handled by your malloc
6544 library. Squid does not pre-allocate any memory, just safe-keeps
6545 objects that otherwise would be free()d. Thus, it is safe to set
6546 memory_pools_limit to a reasonably high value even if your
6547 configuration will use less memory.
6549 If set to zero, Squid will keep all memory it can. That is, there
6550 will be no limit on the total amount of memory used for safe-keeping.
6552 To disable memory allocation optimization, do not set
6553 memory_pools_limit to 0. Set memory_pools to "off" instead.
6555 An overhead for maintaining memory pools is not taken into account
6556 when the limit is checked. This overhead is close to four bytes per
6557 object kept. However, pools may actually _save_ memory because of
6558 reduced memory thrashing in your malloc library.
6562 COMMENT: on|off|transparent|truncate|delete
6565 LOC: opt_forwarded_for
6567 If set to "on", Squid will append your client's IP address
6568 in the HTTP requests it forwards. By default it looks like:
6570 X-Forwarded-For: 192.1.2.3
6572 If set to "off", it will appear as
6574 X-Forwarded-For: unknown
6576 If set to "transparent", Squid will not alter the
6577 X-Forwarded-For header in any way.
6579 If set to "delete", Squid will delete the entire
6580 X-Forwarded-For header.
6582 If set to "truncate", Squid will remove all existing
6583 X-Forwarded-For entries, and place itself as the sole entry.
6586 NAME: cachemgr_passwd
6587 TYPE: cachemgrpasswd
6589 LOC: Config.passwd_list
6591 Specify passwords for cachemgr operations.
6593 Usage: cachemgr_passwd password action action ...
6595 Some valid actions are (see cache manager menu for a full list):
6635 * Indicates actions which will not be performed without a
6636 valid password, others can be performed if not listed here.
6638 To disable an action, set the password to "disable".
6639 To allow performing an action without a password, set the
6642 Use the keyword "all" to set the same password for all actions.
6645 cachemgr_passwd secret shutdown
6646 cachemgr_passwd lesssssssecret info stats/objects
6647 cachemgr_passwd disable all
6654 LOC: Config.onoff.client_db
6656 If you want to disable collecting per-client statistics,
6657 turn off client_db here.
6660 NAME: refresh_all_ims
6664 LOC: Config.onoff.refresh_all_ims
6666 When you enable this option, squid will always check
6667 the origin server for an update when a client sends an
6668 If-Modified-Since request. Many browsers use IMS
6669 requests when the user requests a reload, and this
6670 ensures those clients receive the latest version.
6672 By default (off), squid may return a Not Modified response
6673 based on the age of the cached version.
6676 NAME: reload_into_ims
6677 IFDEF: HTTP_VIOLATIONS
6681 LOC: Config.onoff.reload_into_ims
6683 When you enable this option, client no-cache or ``reload''
6684 requests will be changed to If-Modified-Since requests.
6685 Doing this VIOLATES the HTTP standard. Enabling this
6686 feature could make you liable for problems which it
6689 see also refresh_pattern for a more selective approach.
6692 NAME: maximum_single_addr_tries
6694 LOC: Config.retry.maxtries
6697 This sets the maximum number of connection attempts for a
6698 host that only has one address (for multiple-address hosts,
6699 each address is tried once).
6701 The default value is one attempt, the (not recommended)
6702 maximum is 255 tries. A warning message will be generated
6703 if it is set to a value greater than ten.
6705 Note: This is in addition to the request re-forwarding which
6706 takes place if Squid fails to get a satisfying response.
6709 NAME: retry_on_error
6711 LOC: Config.retry.onerror
6714 If set to on Squid will automatically retry requests when
6715 receiving an error response. This is mainly useful if you
6716 are in a complex cache hierarchy to work around access
6720 NAME: as_whois_server
6722 LOC: Config.as_whois_server
6723 DEFAULT: whois.ra.net
6724 DEFAULT_IF_NONE: whois.ra.net
6726 WHOIS server to query for AS numbers. NOTE: AS numbers are
6727 queried only when Squid starts up, not for every request.
6732 LOC: Config.onoff.offline
6735 Enable this option and Squid will never try to validate cached
6739 NAME: uri_whitespace
6740 TYPE: uri_whitespace
6741 LOC: Config.uri_whitespace
6744 What to do with requests that have whitespace characters in the
6747 strip: The whitespace characters are stripped out of the URL.
6748 This is the behavior recommended by RFC2396.
6749 deny: The request is denied. The user receives an "Invalid
6751 allow: The request is allowed and the URI is not changed. The
6752 whitespace characters remain in the URI. Note the
6753 whitespace is passed to redirector processes if they
6755 encode: The request is allowed and the whitespace characters are
6756 encoded according to RFC1738. This could be considered
6757 a violation of the HTTP/1.1
6758 RFC because proxies are not allowed to rewrite URI's.
6759 chop: The request is allowed and the URI is chopped at the
6760 first whitespace. This might also be considered a
6766 LOC: Config.chroot_dir
6769 Specifies a directory where Squid should do a chroot() while
6770 initializing. This also causes Squid to fully drop root
6771 privileges after initializing. This means, for example, if you
6772 use a HTTP port less than 1024 and try to reconfigure, you may
6773 get an error saying that Squid can not open the port.
6776 NAME: balance_on_multiple_ip
6778 LOC: Config.onoff.balance_on_multiple_ip
6781 Modern IP resolvers in squid sort lookup results by preferred access.
6782 By default squid will use these IP in order and only rotates to
6783 the next listed when the most preffered fails.
6785 Some load balancing servers based on round robin DNS have been
6786 found not to preserve user session state across requests
6787 to different IP addresses.
6789 Enabling this directive Squid rotates IP's per request.
6792 NAME: pipeline_prefetch
6794 LOC: Config.onoff.pipeline_prefetch
6797 To boost the performance of pipelined requests to closer
6798 match that of a non-proxied environment Squid can try to fetch
6799 up to two requests in parallel from a pipeline.
6801 Defaults to off for bandwidth management and access logging
6805 NAME: high_response_time_warning
6808 LOC: Config.warnings.high_rptm
6811 If the one-minute median response time exceeds this value,
6812 Squid prints a WARNING with debug level 0 to get the
6813 administrators attention. The value is in milliseconds.
6816 NAME: high_page_fault_warning
6818 LOC: Config.warnings.high_pf
6821 If the one-minute average page fault rate exceeds this
6822 value, Squid prints a WARNING with debug level 0 to get
6823 the administrators attention. The value is in page faults
6827 NAME: high_memory_warning
6829 LOC: Config.warnings.high_memory
6832 If the memory usage (as determined by mallinfo) exceeds
6833 this amount, Squid prints a WARNING with debug level 0 to get
6834 the administrators attention.
6837 NAME: sleep_after_fork
6838 COMMENT: (microseconds)
6840 LOC: Config.sleep_after_fork
6843 When this is set to a non-zero value, the main Squid process
6844 sleeps the specified number of microseconds after a fork()
6845 system call. This sleep may help the situation where your
6846 system reports fork() failures due to lack of (virtual)
6847 memory. Note, however, if you have a lot of child
6848 processes, these sleep delays will add up and your
6849 Squid will not service requests for some amount of time
6850 until all the child processes have been started.
6851 On Windows value less then 1000 (1 milliseconds) are
6855 NAME: windows_ipaddrchangemonitor
6856 IFDEF: _SQUID_MSWIN_
6860 LOC: Config.onoff.WIN32_IpAddrChangeMonitor
6862 On Windows Squid by default will monitor IP address changes and will
6863 reconfigure itself after any detected event. This is very useful for
6864 proxies connected to internet with dial-up interfaces.
6865 In some cases (a Proxy server acting as VPN gateway is one) it could be
6866 desiderable to disable this behaviour setting this to 'off'.
6867 Note: after changing this, Squid service must be restarted.
6872 IFDEF: USE_SQUID_EUI
6874 LOC: Eui::TheConfig.euiLookup
6876 Whether to lookup the EUI or MAC address of a connected client.