3 # $Id: cf.data.pre,v 1.492 2007/12/29 18:20:22 hno Exp $
5 # SQUID Web Proxy Cache http://www.squid-cache.org/
6 # ----------------------------------------------------------
8 # Squid is the result of efforts by numerous individuals from
9 # the Internet community; see the CONTRIBUTORS file for full
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17 # This program is free software; you can redistribute it and/or modify
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20 # (at your option) any later version.
22 # This program is distributed in the hope that it will be useful,
23 # but WITHOUT ANY WARRANTY; without even the implied warranty of
24 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
25 # GNU General Public License for more details.
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33 WELCOME TO SQUID @VERSION@
34 ----------------------------
36 This is the default Squid configuration file. You may wish
37 to look at the Squid home page (http://www.squid-cache.org/)
38 for the FAQ and other documentation.
40 The default Squid config file shows what the defaults for
41 various options happen to be. If you don't need to change the
42 default, you shouldn't uncomment the line. Doing so may cause
43 run-time problems. In some cases "none" refers to no default
44 setting at all, while in other cases it refers to a valid
45 option - the comments for that keyword indicate if this is the
51 OPTIONS FOR AUTHENTICATION
52 -----------------------------------------------------------------------------
57 LOC: Config.authConfiguration
60 This is used to define parameters for the various authentication
61 schemes supported by Squid.
63 format: auth_param scheme parameter [setting]
65 The order in which authentication schemes are presented to the client is
66 dependent on the order the scheme first appears in config file. IE
67 has a bug (it's not RFC 2617 compliant) in that it will use the basic
68 scheme if basic is the first entry presented, even if more secure
69 schemes are presented. For now use the order in the recommended
70 settings section below. If other browsers have difficulties (don't
71 recognize the schemes offered even if you are using basic) either
72 put basic first, or disable the other schemes (by commenting out their
75 Once an authentication scheme is fully configured, it can only be
76 shutdown by shutting squid down and restarting. Changes can be made on
77 the fly and activated with a reconfigure. I.E. You can change to a
78 different helper, but not unconfigure the helper completely.
80 Please note that while this directive defines how Squid processes
81 authentication it does not automatically activate authentication.
82 To use authentication you must in addition make use of ACLs based
83 on login name in http_access (proxy_auth, proxy_auth_regex or
84 external with %LOGIN used in the format tag). The browser will be
85 challenged for authentication on the first such acl encountered
86 in http_access processing and will also be re-challenged for new
87 login credentials if the request is being denied by a proxy_auth
90 WARNING: authentication can't be used in a transparently intercepting
91 proxy as the client then thinks it is talking to an origin server and
92 not the proxy. This is a limitation of bending the TCP/IP protocol to
93 transparently intercepting port 80, not a limitation in Squid.
95 === Parameters for the basic scheme follow. ===
98 Specify the command for the external authenticator. Such a program
99 reads a line containing "username password" and replies "OK" or
100 "ERR" in an endless loop. "ERR" responses may optionally be followed
101 by a error description available as %m in the returned error page.
102 If you use an authenticator, make sure you have 1 acl of type proxy_auth.
104 By default, the basic authentication scheme is not used unless a
105 program is specified.
107 If you want to use the traditional NCSA proxy authentication, set
108 this line to something like
110 auth_param basic program @DEFAULT_PREFIX@/libexec/ncsa_auth @DEFAULT_PREFIX@/etc/passwd
112 "children" numberofchildren
113 The number of authenticator processes to spawn. If you start too few
114 Squid will have to wait for them to process a backlog of credential
115 verifications, slowing it down. When password verifications are
116 done via a (slow) network you are likely to need lots of
117 authenticator processes.
118 auth_param basic children 5
120 "concurrency" concurrency
121 The number of concurrent requests the helper can process.
122 The default of 0 is used for helpers who only supports
123 one request at a time. Setting this changes the protocol used to
124 include a channel number first on the request/response line, allowing
125 multiple requests to be sent to the same helper in parallell without
126 wating for the response.
127 Must not be set unless it's known the helper supports this.
128 auth_param basic concurrency 0
131 Specifies the realm name which is to be reported to the
132 client for the basic proxy authentication scheme (part of
133 the text the user will see when prompted their username and
134 password). There is no default.
135 auth_param basic realm Squid proxy-caching web server
137 "credentialsttl" timetolive
138 Specifies how long squid assumes an externally validated
139 username:password pair is valid for - in other words how
140 often the helper program is called for that user. Set this
141 low to force revalidation with short lived passwords. Note
142 setting this high does not impact your susceptibility
143 to replay attacks unless you are using an one-time password
144 system (such as SecureID). If you are using such a system,
145 you will be vulnerable to replay attacks unless you also
146 use the max_user_ip ACL in an http_access rule.
148 "casesensitive" on|off
149 Specifies if usernames are case sensitive. Most user databases are
150 case insensitive allowing the same username to be spelled using both
151 lower and upper case letters, but some are case sensitive. This
152 makes a big difference for user_max_ip ACL processing and similar.
153 auth_param basic casesensitive off
155 === Parameters for the digest scheme follow ===
158 Specify the command for the external authenticator. Such
159 a program reads a line containing "username":"realm" and
160 replies with the appropriate H(A1) value hex encoded or
161 ERR if the user (or his H(A1) hash) does not exists.
162 See rfc 2616 for the definition of H(A1).
163 "ERR" responses may optionally be followed by a error description
164 available as %m in the returned error page.
166 By default, the digest authentication scheme is not used unless a
167 program is specified.
169 If you want to use a digest authenticator, set this line to
172 auth_param digest program @DEFAULT_PREFIX@/bin/digest_auth_pw @DEFAULT_PREFIX@/etc/digpass
174 "children" numberofchildren
175 The number of authenticator processes to spawn (no default).
176 If you start too few Squid will have to wait for them to
177 process a backlog of H(A1) calculations, slowing it down.
178 When the H(A1) calculations are done via a (slow) network
179 you are likely to need lots of authenticator processes.
180 auth_param digest children 5
183 Specifies the realm name which is to be reported to the
184 client for the digest proxy authentication scheme (part of
185 the text the user will see when prompted their username and
186 password). There is no default.
187 auth_param digest realm Squid proxy-caching web server
189 "nonce_garbage_interval" timeinterval
190 Specifies the interval that nonces that have been issued
191 to client_agent's are checked for validity.
193 "nonce_max_duration" timeinterval
194 Specifies the maximum length of time a given nonce will be
197 "nonce_max_count" number
198 Specifies the maximum number of times a given nonce can be
201 "nonce_strictness" on|off
202 Determines if squid requires strict increment-by-1 behavior
203 for nonce counts, or just incrementing (off - for use when
204 useragents generate nonce counts that occasionally miss 1
205 (ie, 1,2,4,6)). Default off.
207 "check_nonce_count" on|off
208 This directive if set to off can disable the nonce count check
209 completely to work around buggy digest qop implementations in
210 certain mainstream browser versions. Default on to check the
211 nonce count to protect from authentication replay attacks.
213 "post_workaround" on|off
214 This is a workaround to certain buggy browsers who sends
215 an incorrect request digest in POST requests when reusing
216 the same nonce as acquired earlier on a GET request.
218 === NTLM scheme options follow ===
221 Specify the command for the external NTLM authenticator.
222 Such a program reads exchanged NTLMSSP packets with
223 the browser via Squid until authentication is completed.
224 If you use an NTLM authenticator, make sure you have 1 acl
225 of type proxy_auth. By default, the NTLM authenticator_program
228 auth_param ntlm program @DEFAULT_PREFIX@/bin/ntlm_auth
230 "children" numberofchildren
231 The number of authenticator processes to spawn (no default).
232 If you start too few Squid will have to wait for them to
233 process a backlog of credential verifications, slowing it
234 down. When credential verifications are done via a (slow)
235 network you are likely to need lots of authenticator
238 auth_param ntlm children 5
241 If you experience problems with PUT/POST requests when using the
242 Negotiate authentication scheme then you can try setting this to
243 off. This will cause Squid to forcibly close the connection on
244 the initial requests where the browser asks which schemes are
245 supported by the proxy.
247 auth_param ntlm keep_alive on
249 === Options for configuring the NEGOTIATE auth-scheme follow ===
252 Specify the command for the external Negotiate authenticator.
253 This protocol is used in Microsoft Active-Directory enabled setups with
254 the Microsoft Internet Explorer or Mozilla Firefox browsers.
255 Its main purpose is to exchange credentials with the Squid proxy
256 using the Kerberos mechanisms.
257 If you use a Negotiate authenticator, make sure you have at least one acl
258 of type proxy_auth active. By default, the negotiate authenticator_program
260 The only supported program for this role is the ntlm_auth
261 program distributed as part of Samba, version 4 or later.
263 auth_param negotiate program @DEFAULT_PREFIX@/bin/ntlm_auth --helper-protocol=gss-spnego
265 "children" numberofchildren
266 The number of authenticator processes to spawn (no default).
267 If you start too few Squid will have to wait for them to
268 process a backlog of credential verifications, slowing it
269 down. When crendential verifications are done via a (slow)
270 network you are likely to need lots of authenticator
272 auth_param negotiate children 5
275 If you experience problems with PUT/POST requests when using the
276 Negotiate authentication scheme then you can try setting this to
277 off. This will cause Squid to forcibly close the connection on
278 the initial requests where the browser asks which schemes are
279 supported by the proxy.
281 auth_param negotiate keep_alive on
284 #Recommended minimum configuration per scheme:
285 #auth_param negotiate program <uncomment and complete this line to activate>
286 #auth_param negotiate children 5
287 #auth_param negotiate keep_alive on
288 #auth_param ntlm program <uncomment and complete this line to activate>
289 #auth_param ntlm children 5
290 #auth_param ntlm keep_alive on
291 #auth_param digest program <uncomment and complete this line>
292 #auth_param digest children 5
293 #auth_param digest realm Squid proxy-caching web server
294 #auth_param digest nonce_garbage_interval 5 minutes
295 #auth_param digest nonce_max_duration 30 minutes
296 #auth_param digest nonce_max_count 50
297 #auth_param basic program <uncomment and complete this line>
298 #auth_param basic children 5
299 #auth_param basic realm Squid proxy-caching web server
300 #auth_param basic credentialsttl 2 hours
304 NAME: authenticate_cache_garbage_interval
307 LOC: Config.authenticateGCInterval
309 The time period between garbage collection across the username cache.
310 This is a tradeoff between memory utilization (long intervals - say
311 2 days) and CPU (short intervals - say 1 minute). Only change if you
315 NAME: authenticate_ttl
318 LOC: Config.authenticateTTL
320 The time a user & their credentials stay in the logged in
321 user cache since their last request. When the garbage
322 interval passes, all user credentials that have passed their
323 TTL are removed from memory.
326 NAME: authenticate_ip_ttl
328 LOC: Config.authenticateIpTTL
331 If you use proxy authentication and the 'max_user_ip' ACL,
332 this directive controls how long Squid remembers the IP
333 addresses associated with each user. Use a small value
334 (e.g., 60 seconds) if your users might change addresses
335 quickly, as is the case with dialups. You might be safe
336 using a larger value (e.g., 2 hours) in a corporate LAN
337 environment with relatively static address assignments.
342 -----------------------------------------------------------------------------
345 NAME: external_acl_type
346 TYPE: externalAclHelper
347 LOC: Config.externalAclHelperList
350 This option defines external acl classes using a helper program
351 to look up the status
353 external_acl_type name [options] FORMAT.. /path/to/helper [helper arguments..]
357 ttl=n TTL in seconds for cached results (defaults to 3600
360 TTL for cached negative lookups (default same
362 children=n Number of acl helper processes spawn to service
363 external acl lookups of this type. (default 5)
364 concurrency=n concurrency level per process. Only used with helpers
365 capable of processing more than one query at a time.
366 cache=n result cache size, 0 is unbounded (default)
367 grace=n Percentage remaining of TTL where a refresh of a
368 cached entry should be initiated without needing to
369 wait for a new reply. (default 0 for no grace period)
370 protocol=2.5 Compatibility mode for Squid-2.5 external acl helpers
371 ipv4 / ipv6 IP-mode used to communicate to this helper.
372 For compatability with older configurations and helpers
373 'ipv4' is the default unless --with-localhost-ipv6 is used.
374 --with-localhost-ipv6 changes the default to 'ipv6'.
375 SPECIAL NOTE: these options override --with-localhost-ipv6
377 FORMAT specifications
379 %LOGIN Authenticated user login name
380 %EXT_USER Username from external acl
381 %IDENT Ident user name
383 %SRCPORT Client source port
386 %PROTO Requested protocol
388 %PATH Requested URL path
389 %METHOD Request method
390 %MYADDR Squid interface address
391 %MYPORT Squid http_port number
392 %PATH Requested URL-path (including query-string if any)
393 %USER_CERT SSL User certificate in PEM format
394 %USER_CERTCHAIN SSL User certificate chain in PEM format
395 %USER_CERT_xx SSL User certificate subject attribute xx
396 %USER_CA_xx SSL User certificate issuer attribute xx
397 %{Header} HTTP request header
398 %{Hdr:member} HTTP request header list member
400 HTTP request header list member using ; as
401 list separator. ; can be any non-alphanumeric
404 In addition to the above, any string specified in the referencing
405 acl will also be included in the helper request line, after the
406 specified formats (see the "acl external" directive)
408 The helper receives lines per the above format specification,
409 and returns lines starting with OK or ERR indicating the validity
410 of the request and optionally followed by additional keywords with
413 General result syntax:
415 OK/ERR keyword=value ...
419 user= The users name (login)
420 password= The users password (for login= cache_peer option)
421 message= Message describing the reason. Available as %o
423 tag= Apply a tag to a request (for both ERR and OK results)
424 Only sets a tag, does not alter existing tags.
425 log= String to be logged in access.log. Available as
426 %ea in logformat specifications
428 If protocol=3.0 (the default) then URL escaping is used to protect
429 each value in both requests and responses.
431 If using protocol=2.5 then all values need to be enclosed in quotes
432 if they may contain whitespace, or the whitespace escaped using \.
433 And quotes or \ characters within the keyword value must be \ escaped.
435 When using the concurrency= option the protocol is changed by
436 introducing a query channel tag infront of the request/response.
437 The query channel tag is a number between 0 and concurrency-1.
445 Defining an Access List
447 acl aclname acltype string1 ...
448 acl aclname acltype "file" ...
450 when using "file", the file should contain one item per line
452 acltype is one of the types described below
454 By default, regular expressions are CASE-SENSITIVE. To make
455 them case-insensitive, use the -i option.
457 acl aclname src ip-address/netmask ... (clients IP address)
458 acl aclname src addr1-addr2/netmask ... (range of addresses)
459 acl aclname dst ip-address/netmask ... (URL host's IP address)
460 acl aclname myip ip-address/netmask ... (local socket IP address)
462 acl aclname arp mac-address ... (xx:xx:xx:xx:xx:xx notation)
463 # The arp ACL requires the special configure option --enable-arp-acl.
464 # Furthermore, the ARP ACL code is not portable to all operating systems.
465 # It works on Linux, Solaris, Windows, FreeBSD, and some other *BSD variants.
467 # NOTE: Squid can only determine the MAC address for clients that are on
468 # the same subnet. If the client is on a different subnet, then Squid cannot
469 # find out its MAC address.
471 acl aclname srcdomain .foo.com ... # reverse lookup, client IP
472 acl aclname dstdomain .foo.com ... # Destination server from URL
473 acl aclname srcdom_regex [-i] xxx ... # regex matching client name
474 acl aclname dstdom_regex [-i] xxx ... # regex matching server
475 # For dstdomain and dstdom_regex a reverse lookup is tried if a IP
476 # based URL is used and no match is found. The name "none" is used
477 # if the reverse lookup fails.
479 acl aclname http_status 200 301 500- 400-403 ... # status code in reply
481 acl aclname time [day-abbrevs] [h1:m1-h2:m2]
490 h1:m1 must be less than h2:m2
491 acl aclname url_regex [-i] ^http:// ... # regex matching on whole URL
492 acl aclname urlpath_regex [-i] \.gif$ ... # regex matching on URL path
493 acl aclname port 80 70 21 ...
494 acl aclname port 0-1024 ... # ranges allowed
495 acl aclname myport 3128 ... # (local socket TCP port)
496 acl aclname proto HTTP FTP ...
497 acl aclname method GET POST ...
498 acl aclname browser [-i] regexp ...
499 # pattern match on User-Agent header (see also req_header below)
500 acl aclname referer_regex [-i] regexp ...
501 # pattern match on Referer header
502 # Referer is highly unreliable, so use with care
503 acl aclname ident username ...
504 acl aclname ident_regex [-i] pattern ...
505 # string match on ident output.
506 # use REQUIRED to accept any non-null ident.
507 acl aclname src_as number ...
508 acl aclname dst_as number ...
509 # Except for access control, AS numbers can be used for
510 # routing of requests to specific caches. Here's an
511 # example for routing all requests for AS#1241 and only
512 # those to mycache.mydomain.net:
513 # acl asexample dst_as 1241
514 # cache_peer_access mycache.mydomain.net allow asexample
515 # cache_peer_access mycache_mydomain.net deny all
517 acl aclname proxy_auth [-i] username ...
518 acl aclname proxy_auth_regex [-i] pattern ...
519 # list of valid usernames
520 # use REQUIRED to accept any valid username.
522 # NOTE: when a Proxy-Authentication header is sent but it is not
523 # needed during ACL checking the username is NOT logged
526 # NOTE: proxy_auth requires a EXTERNAL authentication program
527 # to check username/password combinations (see
528 # auth_param directive).
530 # NOTE: proxy_auth can't be used in a transparent proxy as
531 # the browser needs to be configured for using a proxy in order
532 # to respond to proxy authentication.
534 acl aclname snmp_community string ...
535 # A community string to limit access to your SNMP Agent
538 # acl snmppublic snmp_community public
540 acl aclname maxconn number
541 # This will be matched when the client's IP address has
542 # more than <number> HTTP connections established.
544 acl aclname max_user_ip [-s] number
545 # This will be matched when the user attempts to log in from more
546 # than <number> different ip addresses. The authenticate_ip_ttl
547 # parameter controls the timeout on the ip entries.
548 # If -s is specified the limit is strict, denying browsing
549 # from any further IP addresses until the ttl has expired. Without
550 # -s Squid will just annoy the user by "randomly" denying requests.
551 # (the counter is reset each time the limit is reached and a
553 # NOTE: in acceleration mode or where there is mesh of child proxies,
554 # clients may appear to come from multiple addresses if they are
555 # going through proxy farms, so a limit of 1 may cause user problems.
557 acl aclname req_mime_type mime-type1 ...
558 # regex match against the mime type of the request generated
559 # by the client. Can be used to detect file upload or some
560 # types HTTP tunneling requests.
561 # NOTE: This does NOT match the reply. You cannot use this
562 # to match the returned file type.
564 acl aclname req_header header-name [-i] any\.regex\.here
565 # regex match against any of the known request headers. May be
566 # thought of as a superset of "browser", "referer" and "mime-type"
569 acl aclname rep_mime_type mime-type1 ...
570 # regex match against the mime type of the reply received by
571 # squid. Can be used to detect file download or some
572 # types HTTP tunneling requests.
573 # NOTE: This has no effect in http_access rules. It only has
574 # effect in rules that affect the reply data stream such as
577 acl aclname rep_header header-name [-i] any\.regex\.here
578 # regex match against any of the known reply headers. May be
579 # thought of as a superset of "browser", "referer" and "mime-type"
582 acl acl_name external class_name [arguments...]
583 # external ACL lookup via a helper class defined by the
584 # external_acl_type directive.
586 acl aclname user_cert attribute values...
587 # match against attributes in a user SSL certificate
588 # attribute is one of DN/C/O/CN/L/ST
590 acl aclname ca_cert attribute values...
591 # match against attributes a users issuing CA SSL certificate
592 # attribute is one of DN/C/O/CN/L/ST
594 acl aclname ext_user username ...
595 acl aclname ext_user_regex [-i] pattern ...
596 # string match on username returned by external acl helper
597 # use REQUIRED to accept any non-null user name.
600 acl macaddress arp 09:00:2b:23:45:67
601 acl myexample dst_as 1241
602 acl password proxy_auth REQUIRED
603 acl fileupload req_mime_type -i ^multipart/form-data$
604 acl javascript rep_mime_type -i ^application/x-javascript$
607 #Recommended minimum configuration:
608 acl manager proto cache_object
609 acl localhost src 127.0.0.1/32
610 acl to_localhost dst 127.0.0.0/8
612 # Example rule allowing access from your local networks.
613 # Adapt to list your (internal) IP networks from where browsing
615 acl localnet src 10.0.0.0/8 # RFC1918 possible internal network
616 acl localnet src 172.16.0.0/12 # RFC1918 possible internal network
617 acl localnet src 192.168.0.0/16 # RFC1918 possible internal network
619 acl SSL_ports port 443
620 acl Safe_ports port 80 # http
621 acl Safe_ports port 21 # ftp
622 acl Safe_ports port 443 # https
623 acl Safe_ports port 70 # gopher
624 acl Safe_ports port 210 # wais
625 acl Safe_ports port 1025-65535 # unregistered ports
626 acl Safe_ports port 280 # http-mgmt
627 acl Safe_ports port 488 # gss-http
628 acl Safe_ports port 591 # filemaker
629 acl Safe_ports port 777 # multiling http
630 acl CONNECT method CONNECT
636 LOC: Config.accessList.http
638 DEFAULT_IF_NONE: deny all
640 Allowing or Denying access based on defined access lists
642 Access to the HTTP port:
643 http_access allow|deny [!]aclname ...
645 NOTE on default values:
647 If there are no "access" lines present, the default is to deny
650 If none of the "access" lines cause a match, the default is the
651 opposite of the last line in the list. If the last line was
652 deny, the default is allow. Conversely, if the last line
653 is allow, the default will be deny. For these reasons, it is a
654 good idea to have an "deny all" or "allow all" entry at the end
655 of your access lists to avoid potential confusion.
658 #Recommended minimum configuration:
660 # Only allow cachemgr access from localhost
661 http_access allow manager localhost
662 http_access deny manager
663 # Deny requests to unknown ports
664 http_access deny !Safe_ports
665 # Deny CONNECT to other than SSL ports
666 http_access deny CONNECT !SSL_ports
668 # We strongly recommend the following be uncommented to protect innocent
669 # web applications running on the proxy server who think the only
670 # one who can access services on "localhost" is a local user
671 #http_access deny to_localhost
673 # INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS
675 # Example rule allowing access from your local networks.
676 # Adapt localnet in the ACL section to list your (internal) IP networks
677 # from where browsing should be allowed
678 http_access allow localnet
680 # And finally deny all other access to this proxy
685 NAME: http_reply_access
687 LOC: Config.accessList.reply
690 Allow replies to client requests. This is complementary to http_access.
692 http_reply_access allow|deny [!] aclname ...
694 NOTE: if there are no access lines present, the default is to allow
697 If none of the access lines cause a match the opposite of the
698 last line will apply. Thus it is good practice to end the rules
699 with an "allow all" or "deny all" entry.
704 LOC: Config.accessList.icp
706 DEFAULT_IF_NONE: deny all
708 Allowing or Denying access to the ICP port based on defined
711 icp_access allow|deny [!]aclname ...
713 See http_access for details
716 #Allow ICP queries from local networks only
717 icp_access allow localnet
725 LOC: Config.accessList.htcp
727 DEFAULT_IF_NONE: deny all
729 Allowing or Denying access to the HTCP port based on defined
732 htcp_access allow|deny [!]aclname ...
734 See http_access for details
736 NOTE: The default if no htcp_access lines are present is to
737 deny all traffic. This default may cause problems with peers
738 using the htcp or htcp-oldsquid options.
741 #Allow HTCP queries from local networks only
742 htcp_access allow localnet
747 NAME: htcp_clr_access
750 LOC: Config.accessList.htcp_clr
752 DEFAULT_IF_NONE: deny all
754 Allowing or Denying access to purge content using HTCP based
755 on defined access lists
757 htcp_clr_access allow|deny [!]aclname ...
759 See http_access for details
761 #Allow HTCP CLR requests from trusted peers
762 acl htcp_clr_peer src 172.16.1.2
763 htcp_clr_access allow htcp_clr_peer
768 LOC: Config.accessList.miss
771 Use to force your neighbors to use you as a sibling instead of
772 a parent. For example:
774 acl localclients src 172.16.0.0/16
775 miss_access allow localclients
776 miss_access deny !localclients
778 This means only your local clients are allowed to fetch
779 MISSES and all other clients can only fetch HITS.
781 By default, allow all clients who passed the http_access rules
782 to fetch MISSES from us.
786 # miss_access allow all
790 NAME: ident_lookup_access
794 DEFAULT_IF_NONE: deny all
795 LOC: Config.accessList.identLookup
797 A list of ACL elements which, if matched, cause an ident
798 (RFC 931) lookup to be performed for this request. For
799 example, you might choose to always perform ident lookups
800 for your main multi-user Unix boxes, but not for your Macs
801 and PCs. By default, ident lookups are not performed for
804 To enable ident lookups for specific client addresses, you
805 can follow this example:
807 acl ident_aware_hosts src 198.168.1.0/255.255.255.0
808 ident_lookup_access allow ident_aware_hosts
809 ident_lookup_access deny all
811 Only src type ACL checks are fully supported. A src_domain
812 ACL might work at times, but it will not always provide
816 NAME: reply_body_max_size
817 COMMENT: size [acl acl...]
820 LOC: Config.ReplyBodySize
822 This option specifies the maximum size of a reply body. It can be
823 used to prevent users from downloading very large files, such as
824 MP3's and movies. When the reply headers are received, the
825 reply_body_max_size lines are processed, and the first line where
826 all (if any) listed ACLs are true is used as the maximum body size
829 This size is checked twice. First when we get the reply headers,
830 we check the content-length value. If the content length value exists
831 and is larger than the allowed size, the request is denied and the
832 user receives an error message that says "the request or reply
833 is too large." If there is no content-length, and the reply
834 size exceeds this limit, the client's connection is just closed
835 and they will receive a partial reply.
837 WARNING: downstream caches probably can not detect a partial reply
838 if there is no content-length header, so they will cache
839 partial responses and give them out as hits. You should NOT
840 use this option if you have downstream caches.
842 WARNING: A maximum size smaller than the size of squid's error messages
843 will cause an infinite loop and crash squid. Ensure that the smallest
844 non-zero value you use is greater that the maximum header size plus
845 the size of your largest error page.
847 If you set this parameter none (the default), there will be
853 -----------------------------------------------------------------------------
856 NAME: http_port ascii_port
859 LOC: Config.Sockaddr.http
861 Usage: port [options]
862 hostname:port [options]
863 1.2.3.4:port [options]
865 The socket addresses where Squid will listen for HTTP client
866 requests. You may specify multiple socket addresses.
867 There are three forms: port alone, hostname with port, and
868 IP address with port. If you specify a hostname or IP
869 address, Squid binds the socket to that specific
870 address. This replaces the old 'tcp_incoming_address'
871 option. Most likely, you do not need to bind to a specific
872 address, so you can use the port number alone.
874 If you are running Squid in accelerator mode, you
875 probably want to listen on port 80 also, or instead.
877 The -a command line option may be used to specify additional
878 port(s) where Squid listens for proxy request. Such ports will
879 be plain proxy ports with no options.
881 You may specify multiple socket addresses on multiple lines.
885 transparent Support for transparent interception of
886 outgoing requests without browser settings.
888 tproxy Support Linux TPROXY for spoofing outgoing
889 connections using the client IP address.
891 accel Accelerator mode. Also needs at least one of
892 vhost / vport / defaultsite.
894 defaultsite=domainname
895 What to use for the Host: header if it is not present
896 in a request. Determines what site (not origin server)
897 accelerators should consider the default.
900 vhost Accelerator mode using Host header for virtual
901 domain support. Implies accel.
903 vport Accelerator with IP based virtual host support.
906 vport=NN As above, but uses specified port number rather
907 than the http_port number. Implies accel.
909 protocol= Protocol to reconstruct accelerated requests with.
912 disable-pmtu-discovery=
913 Control Path-MTU discovery usage:
914 off lets OS decide on what to do (default).
915 transparent disable PMTU discovery when transparent
917 always disable always PMTU discovery.
919 In many setups of transparently intercepting proxies
920 Path-MTU discovery can not work on traffic towards the
921 clients. This is the case when the intercepting device
922 does not fully track connections and fails to forward
923 ICMP must fragment messages to the cache server. If you
924 have such setup and experience that certain clients
925 sporadically hang or never complete requests set
926 disable-pmtu-discovery option to 'transparent'.
928 If you run Squid on a dual-homed machine with an internal
929 and an external interface we recommend you to specify the
930 internal address:port in http_port. This way Squid will only be
931 visible on the internal address.
934 # Squid normally listens to port 3128
935 http_port @DEFAULT_HTTP_PORT@
941 TYPE: https_port_list
943 LOC: Config.Sockaddr.https
945 Usage: [ip:]port cert=certificate.pem [key=key.pem] [options...]
947 The socket address where Squid will listen for HTTPS client
950 This is really only useful for situations where you are running
951 squid in accelerator mode and you want to do the SSL work at the
954 You may specify multiple socket addresses on multiple lines,
955 each with their own SSL certificate and/or options.
959 accel Accelerator mode. Also needs at least one of
960 defaultsite or vhost.
962 defaultsite= The name of the https site presented on
963 this port. Implies accel.
965 vhost Accelerator mode using Host header for virtual
966 domain support. Requires a wildcard certificate
967 or other certificate valid for more than one domain.
970 protocol= Protocol to reconstruct accelerated requests with.
973 cert= Path to SSL certificate (PEM format).
975 key= Path to SSL private key file (PEM format)
976 if not specified, the certificate file is
977 assumed to be a combined certificate and
980 version= The version of SSL/TLS supported
981 1 automatic (default)
986 cipher= Colon separated list of supported ciphers.
988 options= Various SSL engine options. The most important
990 NO_SSLv2 Disallow the use of SSLv2
991 NO_SSLv3 Disallow the use of SSLv3
992 NO_TLSv1 Disallow the use of TLSv1
993 SINGLE_DH_USE Always create a new key when using
994 temporary/ephemeral DH key exchanges
995 See src/ssl_support.c or OpenSSL SSL_CTX_set_options
996 documentation for a complete list of options.
998 clientca= File containing the list of CAs to use when
999 requesting a client certificate.
1001 cafile= File containing additional CA certificates to
1002 use when verifying client certificates. If unset
1003 clientca will be used.
1005 capath= Directory containing additional CA certificates
1006 and CRL lists to use when verifying client certificates.
1008 crlfile= File of additional CRL lists to use when verifying
1009 the client certificate, in addition to CRLs stored in
1010 the capath. Implies VERIFY_CRL flag below.
1012 dhparams= File containing DH parameters for temporary/ephemeral
1015 sslflags= Various flags modifying the use of SSL:
1017 Don't request client certificates
1018 immediately, but wait until acl processing
1019 requires a certificate (not yet implemented).
1021 Don't use the default CA lists built in
1024 Don't allow for session reuse. Each connection
1025 will result in a new SSL session.
1027 Verify CRL lists when accepting client
1030 Verify CRL lists for all certificates in the
1031 client certificate chain.
1033 sslcontext= SSL session ID context identifier.
1035 vport Accelerator with IP based virtual host support.
1037 vport=NN As above, but uses specified port number rather
1038 than the https_port number. Implies accel.
1042 NAME: tcp_outgoing_tos tcp_outgoing_ds tcp_outgoing_dscp
1045 LOC: Config.accessList.outgoing_tos
1047 Allows you to select a TOS/Diffserv value to mark outgoing
1048 connections with, based on the username or source address
1051 tcp_outgoing_tos ds-field [!]aclname ...
1053 Example where normal_service_net uses the TOS value 0x00
1054 and normal_service_net uses 0x20
1056 acl normal_service_net src 10.0.0.0/255.255.255.0
1057 acl good_service_net src 10.0.1.0/255.255.255.0
1058 tcp_outgoing_tos 0x00 normal_service_net
1059 tcp_outgoing_tos 0x20 good_service_net
1061 TOS/DSCP values really only have local significance - so you should
1062 know what you're specifying. For more information, see RFC2474 and
1065 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
1066 "default" to use whatever default your host has. Note that in
1067 practice often only values 0 - 63 is usable as the two highest bits
1068 have been redefined for use by ECN (RFC3168).
1070 Processing proceeds in the order specified, and stops at first fully
1073 Note: The use of this directive using client dependent ACLs is
1074 incompatible with the use of server side persistent connections. To
1075 ensure correct results it is best to set server_persisten_connections
1076 to off when using this directive in such configurations.
1079 NAME: clientside_tos
1082 LOC: Config.accessList.clientside_tos
1084 Allows you to select a TOS/Diffserv value to mark client-side
1085 connections with, based on the username or source address
1089 NAME: tcp_outgoing_address
1092 LOC: Config.accessList.outgoing_address
1094 Allows you to map requests to different outgoing IP addresses
1095 based on the username or source address of the user making
1098 tcp_outgoing_address ipaddr [[!]aclname] ...
1100 Example where requests from 10.0.0.0/24 will be forwarded
1101 with source address 10.1.0.1, 10.0.2.0/24 forwarded with
1102 source address 10.1.0.2 and the rest will be forwarded with
1103 source address 10.1.0.3.
1105 acl normal_service_net src 10.0.0.0/255.255.255.0
1106 acl good_service_net src 10.0.1.0/255.255.255.0
1107 tcp_outgoing_address 10.0.0.1 normal_service_net
1108 tcp_outgoing_address 10.0.0.2 good_service_net
1109 tcp_outgoing_address 10.0.0.3
1111 Processing proceeds in the order specified, and stops at first fully
1114 Note: The use of this directive using client dependent ACLs is
1115 incompatible with the use of server side persistent connections. To
1116 ensure correct results it is best to set server_persistent_connections
1117 to off when using this directive in such configurations.
1122 Squid is built with a capability of bridging the IPv4 and IPv6 internets.
1123 tcp_outgoing_address as exampled above breaks this bridging by forcing
1124 all outbound traffic through a certain IPv4 which may be on the wrong
1125 side of the IPv4/IPv6 boundary.
1127 To operate with tcp_outgoing_address and keep the bridging benefits
1128 an additional ACL needs to be used which ensures the IPv6-bound traffic
1129 is never forced or permitted out the IPv4 interface.
1131 acl to_ipv6 dst ipv6
1132 tcp_outgoing_address 2002::c001 good_service_net to_ipv6
1133 tcp_outgoing_address 10.0.0.2 good_service_net !to_ipv6
1135 tcp_outgoing_address 2002::beef normal_service_net to_ipv6
1136 tcp_outgoing_address 10.0.0.1 normal_service_net !to_ipv6
1138 tcp_outgoing_address 2002::1 to_ipv6
1139 tcp_outgoing_address 10.0.0.3 !to_ipv6
1144 -----------------------------------------------------------------------------
1147 NAME: ssl_unclean_shutdown
1151 LOC: Config.SSL.unclean_shutdown
1153 Some browsers (especially MSIE) bugs out on SSL shutdown
1160 LOC: Config.SSL.ssl_engine
1163 The OpenSSL engine to use. You will need to set this if you
1164 would like to use hardware SSL acceleration for example.
1167 NAME: sslproxy_client_certificate
1170 LOC: Config.ssl_client.cert
1173 Client SSL Certificate to use when proxying https:// URLs
1176 NAME: sslproxy_client_key
1179 LOC: Config.ssl_client.key
1182 Client SSL Key to use when proxying https:// URLs
1185 NAME: sslproxy_version
1188 LOC: Config.ssl_client.version
1191 SSL version level to use when proxying https:// URLs
1194 NAME: sslproxy_options
1197 LOC: Config.ssl_client.options
1200 SSL engine options to use when proxying https:// URLs
1203 NAME: sslproxy_cipher
1206 LOC: Config.ssl_client.cipher
1209 SSL cipher list to use when proxying https:// URLs
1212 NAME: sslproxy_cafile
1215 LOC: Config.ssl_client.cafile
1218 file containing CA certificates to use when verifying server
1219 certificates while proxying https:// URLs
1222 NAME: sslproxy_capath
1225 LOC: Config.ssl_client.capath
1228 directory containing CA certificates to use when verifying
1229 server certificates while proxying https:// URLs
1232 NAME: sslproxy_flags
1235 LOC: Config.ssl_client.flags
1238 Various flags modifying the use of SSL while proxying https:// URLs:
1239 DONT_VERIFY_PEER Accept certificates even if they fail to
1241 NO_DEFAULT_CA Don't use the default CA list built in
1245 NAME: sslpassword_program
1248 LOC: Config.Program.ssl_password
1251 Specify a program used for entering SSL key passphrases
1252 when using encrypted SSL certificate keys. If not specified
1253 keys must either be unencrypted, or Squid started with the -N
1254 option to allow it to query interactively for the passphrase.
1258 OPTIONS WHICH AFFECT THE NEIGHBOR SELECTION ALGORITHM
1259 -----------------------------------------------------------------------------
1267 To specify other caches in a hierarchy, use the format:
1269 cache_peer hostname type http-port icp-port [options]
1274 # hostname type port port options
1275 # -------------------- -------- ----- ----- -----------
1276 cache_peer parent.foo.net parent 3128 3130 proxy-only default
1277 cache_peer sib1.foo.net sibling 3128 3130 proxy-only
1278 cache_peer sib2.foo.net sibling 3128 3130 proxy-only
1280 type: either 'parent', 'sibling', or 'multicast'.
1282 proxy-port: The port number where the cache listens for proxy
1285 icp-port: Used for querying neighbor caches about
1286 objects. To have a non-ICP neighbor
1287 specify '7' for the ICP port and make sure the
1288 neighbor machine has the UDP echo port
1289 enabled in its /etc/inetd.conf file.
1290 NOTE: Also requires icp_port option enabled to send/receive
1291 requests via this method.
1301 weighted-round-robin
1308 login=user:password | PASS | *:password
1319 sslcert=/path/to/ssl/certificate
1320 sslkey=/path/to/ssl/key
1324 front-end-https[=on|auto]
1326 use 'proxy-only' to specify objects fetched
1327 from this cache should not be saved locally.
1329 use 'weight=n' to affect the selection of a peer
1330 during any weighted peer-selection mechanisms.
1331 The weight must be an integer; default is 1,
1332 larger weights are favored more.
1333 This option does not affect parent selection if a peering
1334 protocol is not in use.
1336 use 'basetime=n' to specify a base amount to
1337 be subtracted from round trip times of parents.
1338 It is subtracted before division by weight in calculating
1339 which parent to fectch from. If the rtt is less than the
1340 base time the rtt is set to a minimal value.
1342 use 'ttl=n' to specify a IP multicast TTL to use
1343 when sending an ICP queries to this address.
1344 Only useful when sending to a multicast group.
1345 Because we don't accept ICP replies from random
1346 hosts, you must configure other group members as
1347 peers with the 'multicast-responder' option below.
1349 use 'no-query' to NOT send ICP queries to this
1352 use 'background-ping' to only send ICP queries to this
1353 neighbor infrequently. This is used to keep the neighbor
1354 round trip time updated and is usually used in
1355 conjunction with weighted-round-robin.
1357 use 'default' if this is a parent cache which can
1358 be used as a "last-resort" if a peer cannot be located
1359 by any of the peer-selection mechanisms.
1360 If specified more than once, only the first is used.
1362 use 'round-robin' to define a set of parents which
1363 should be used in a round-robin fashion in the
1364 absence of any ICP queries.
1366 use 'weighted-round-robin' to define a set of parents
1367 which should be used in a round-robin fashion with the
1368 frequency of each parent being based on the round trip
1369 time. Closer parents are used more often.
1370 Usually used for background-ping parents.
1372 use 'carp' to define a set of parents which should
1373 be used as a CARP array. The requests will be
1374 distributed among the parents based on the CARP load
1375 balancing hash function based on their weight.
1377 'multicast-responder' indicates the named peer
1378 is a member of a multicast group. ICP queries will
1379 not be sent directly to the peer, but ICP replies
1380 will be accepted from it.
1382 'closest-only' indicates that, for ICP_OP_MISS
1383 replies, we'll only forward CLOSEST_PARENT_MISSes
1384 and never FIRST_PARENT_MISSes.
1386 use 'no-digest' to NOT request cache digests from
1389 'no-netdb-exchange' disables requesting ICMP
1390 RTT database (NetDB) from the neighbor.
1392 use 'no-delay' to prevent access to this neighbor
1393 from influencing the delay pools.
1395 use 'login=user:password' if this is a personal/workgroup
1396 proxy and your parent requires proxy authentication.
1397 Note: The string can include URL escapes (i.e. %20 for
1398 spaces). This also means % must be written as %%.
1400 use 'login=PASS' if users must authenticate against
1401 the upstream proxy or in the case of a reverse proxy
1402 configuration, the origin web server. This will pass
1403 the users credentials as they are to the peer.
1404 This only works for the Basic HTTP authentication scheme.
1405 Note: To combine this with proxy_auth both proxies must
1406 share the same user database as HTTP only allows for
1407 a single login (one for proxy, one for origin server).
1408 Also be warned this will expose your users proxy
1409 password to the peer. USE WITH CAUTION
1411 use 'login=*:password' to pass the username to the
1412 upstream cache, but with a fixed password. This is meant
1413 to be used when the peer is in another administrative
1414 domain, but it is still needed to identify each user.
1415 The star can optionally be followed by some extra
1416 information which is added to the username. This can
1417 be used to identify this proxy to the peer, similar to
1418 the login=username:password option above.
1420 use 'connect-timeout=nn' to specify a peer
1421 specific connect timeout (also see the
1422 peer_connect_timeout directive)
1424 use 'digest-url=url' to tell Squid to fetch the cache
1425 digest (if digests are enabled) for this host from
1426 the specified URL rather than the Squid default
1429 use 'allow-miss' to disable Squid's use of only-if-cached
1430 when forwarding requests to siblings. This is primarily
1431 useful when icp_hit_stale is used by the sibling. To
1432 extensive use of this option may result in forwarding
1433 loops, and you should avoid having two-way peerings
1434 with this option. (for example to deny peer usage on
1435 requests from peer by denying cache_peer_access if the
1438 use 'max-conn=n' to limit the amount of connections Squid
1439 may open to this peer.
1441 use 'htcp' to send HTCP, instead of ICP, queries
1442 to the neighbor. You probably also want to
1443 set the "icp port" to 4827 instead of 3130.
1444 You MUST also set htcp_access expicitly. The default of
1445 deny all will prevent peer traffic.
1447 use 'htcp-oldsquid' to send HTCP to old Squid versions
1448 You MUST also set htcp_access expicitly. The default of
1449 deny all will prevent peer traffic.
1451 'originserver' causes this parent peer to be contacted as
1452 a origin server. Meant to be used in accelerator setups.
1454 use 'name=xxx' if you have multiple peers on the same
1455 host but different ports. This name can be used to
1456 differentiate the peers in cache_peer_access and similar
1459 use 'forceddomain=name' to forcibly set the Host header
1460 of requests forwarded to this peer. Useful in accelerator
1461 setups where the server (peer) expects a certain domain
1462 name and using redirectors to feed this domain name
1465 use 'ssl' to indicate connections to this peer should
1466 be SSL/TLS encrypted.
1468 use 'sslcert=/path/to/ssl/certificate' to specify a client
1469 SSL certificate to use when connecting to this peer.
1471 use 'sslkey=/path/to/ssl/key' to specify the private SSL
1472 key corresponding to sslcert above. If 'sslkey' is not
1473 specified 'sslcert' is assumed to reference a
1474 combined file containing both the certificate and the key.
1476 use sslversion=1|2|3|4 to specify the SSL version to use
1477 when connecting to this peer
1478 1 = automatic (default)
1483 use sslcipher=... to specify the list of valid SSL ciphers
1484 to use when connecting to this peer.
1486 use ssloptions=... to specify various SSL engine options:
1487 NO_SSLv2 Disallow the use of SSLv2
1488 NO_SSLv3 Disallow the use of SSLv3
1489 NO_TLSv1 Disallow the use of TLSv1
1490 See src/ssl_support.c or the OpenSSL documentation for
1491 a more complete list.
1493 use sslcafile=... to specify a file containing
1494 additional CA certificates to use when verifying the
1497 use sslcapath=... to specify a directory containing
1498 additional CA certificates to use when verifying the
1501 use sslcrlfile=... to specify a certificate revocation
1502 list file to use when verifying the peer certificate.
1504 use sslflags=... to specify various flags modifying the
1507 Accept certificates even if they fail to
1510 Don't use the default CA list built in
1513 Don't verify the peer certificate
1514 matches the server name
1516 use ssldomain= to specify the peer name as advertised
1517 in it's certificate. Used for verifying the correctness
1518 of the received peer certificate. If not specified the
1519 peer hostname will be used.
1521 use front-end-https to enable the "Front-End-Https: On"
1522 header needed when using Squid as a SSL frontend in front
1523 of Microsoft OWA. See MS KB document Q307347 for details
1524 on this header. If set to auto the header will
1525 only be added if the request is forwarded as a https://
1529 NAME: cache_peer_domain cache_host_domain
1534 Use to limit the domains for which a neighbor cache will be
1537 cache_peer_domain cache-host domain [domain ...]
1538 cache_peer_domain cache-host !domain
1540 For example, specifying
1542 cache_peer_domain parent.foo.net .edu
1544 has the effect such that UDP query packets are sent to
1545 'bigserver' only when the requested object exists on a
1546 server in the .edu domain. Prefixing the domainname
1547 with '!' means the cache will be queried for objects
1550 NOTE: * Any number of domains may be given for a cache-host,
1551 either on the same or separate lines.
1552 * When multiple domains are given for a particular
1553 cache-host, the first matched domain is applied.
1554 * Cache hosts with no domain restrictions are queried
1556 * There are no defaults.
1557 * There is also a 'cache_peer_access' tag in the ACL
1561 NAME: cache_peer_access
1566 Similar to 'cache_peer_domain' but provides more flexibility by
1569 cache_peer_access cache-host allow|deny [!]aclname ...
1571 The syntax is identical to 'http_access' and the other lists of
1572 ACL elements. See the comments for 'http_access' below, or
1573 the Squid FAQ (http://www.squid-cache.org/FAQ/FAQ-10.html).
1576 NAME: neighbor_type_domain
1577 TYPE: hostdomaintype
1581 usage: neighbor_type_domain neighbor parent|sibling domain domain ...
1583 Modifying the neighbor type for specific domains is now
1584 possible. You can treat some domains differently than the the
1585 default neighbor type specified on the 'cache_peer' line.
1586 Normally it should only be necessary to list domains which
1587 should be treated differently because the default neighbor type
1588 applies for hostnames which do not match domains listed here.
1591 cache_peer cache.foo.org parent 3128 3130
1592 neighbor_type_domain cache.foo.org sibling .com .net
1593 neighbor_type_domain cache.foo.org sibling .au .de
1596 NAME: dead_peer_timeout
1600 LOC: Config.Timeout.deadPeer
1602 This controls how long Squid waits to declare a peer cache
1603 as "dead." If there are no ICP replies received in this
1604 amount of time, Squid will declare the peer dead and not
1605 expect to receive any further ICP replies. However, it
1606 continues to send ICP queries, and will mark the peer as
1607 alive upon receipt of the first subsequent ICP reply.
1609 This timeout also affects when Squid expects to receive ICP
1610 replies from peers. If more than 'dead_peer' seconds have
1611 passed since the last ICP reply was received, Squid will not
1612 expect to receive an ICP reply on the next query. Thus, if
1613 your time between requests is greater than this timeout, you
1614 will see a lot of requests sent DIRECT to origin servers
1615 instead of to your parents.
1618 NAME: hierarchy_stoplist
1621 LOC: Config.hierarchy_stoplist
1623 A list of words which, if found in a URL, cause the object to
1624 be handled directly by this cache. In other words, use this
1625 to not query neighbor caches for certain objects. You may
1626 list this option multiple times.
1627 Note: never_direct overrides this option.
1629 #We recommend you to use at least the following line.
1630 hierarchy_stoplist cgi-bin ?
1635 MEMORY CACHE OPTIONS
1636 -----------------------------------------------------------------------------
1643 LOC: Config.memMaxSize
1645 NOTE: THIS PARAMETER DOES NOT SPECIFY THE MAXIMUM PROCESS SIZE.
1646 IT ONLY PLACES A LIMIT ON HOW MUCH ADDITIONAL MEMORY SQUID WILL
1647 USE AS A MEMORY CACHE OF OBJECTS. SQUID USES MEMORY FOR OTHER
1648 THINGS AS WELL. SEE THE SQUID FAQ SECTION 8 FOR DETAILS.
1650 'cache_mem' specifies the ideal amount of memory to be used
1652 * In-Transit objects
1654 * Negative-Cached objects
1656 Data for these objects are stored in 4 KB blocks. This
1657 parameter specifies the ideal upper limit on the total size of
1658 4 KB blocks allocated. In-Transit objects take the highest
1661 In-transit objects have priority over the others. When
1662 additional space is needed for incoming data, negative-cached
1663 and hot objects will be released. In other words, the
1664 negative-cached and hot objects will fill up any unused space
1665 not needed for in-transit objects.
1667 If circumstances require, this limit will be exceeded.
1668 Specifically, if your incoming request rate requires more than
1669 'cache_mem' of memory to hold in-transit objects, Squid will
1670 exceed this limit to satisfy the new requests. When the load
1671 decreases, blocks will be freed until the high-water mark is
1672 reached. Thereafter, blocks will be used to store hot
1676 NAME: maximum_object_size_in_memory
1680 LOC: Config.Store.maxInMemObjSize
1682 Objects greater than this size will not be attempted to kept in
1683 the memory cache. This should be set high enough to keep objects
1684 accessed frequently in memory to improve performance whilst low
1685 enough to keep larger objects from hoarding cache_mem.
1688 NAME: memory_replacement_policy
1690 LOC: Config.memPolicy
1693 The memory replacement policy parameter determines which
1694 objects are purged from memory when memory space is needed.
1696 See cache_replacement_policy for details.
1701 -----------------------------------------------------------------------------
1704 NAME: cache_replacement_policy
1706 LOC: Config.replPolicy
1709 The cache replacement policy parameter determines which
1710 objects are evicted (replaced) when disk space is needed.
1712 lru : Squid's original list based LRU policy
1713 heap GDSF : Greedy-Dual Size Frequency
1714 heap LFUDA: Least Frequently Used with Dynamic Aging
1715 heap LRU : LRU policy implemented using a heap
1717 Applies to any cache_dir lines listed below this.
1719 The LRU policies keeps recently referenced objects.
1721 The heap GDSF policy optimizes object hit rate by keeping smaller
1722 popular objects in cache so it has a better chance of getting a
1723 hit. It achieves a lower byte hit rate than LFUDA though since
1724 it evicts larger (possibly popular) objects.
1726 The heap LFUDA policy keeps popular objects in cache regardless of
1727 their size and thus optimizes byte hit rate at the expense of
1728 hit rate since one large, popular object will prevent many
1729 smaller, slightly less popular objects from being cached.
1731 Both policies utilize a dynamic aging mechanism that prevents
1732 cache pollution that can otherwise occur with frequency-based
1733 replacement policies.
1735 NOTE: if using the LFUDA replacement policy you should increase
1736 the value of maximum_object_size above its default of 4096 KB to
1737 to maximize the potential byte hit rate improvement of LFUDA.
1739 For more information about the GDSF and LFUDA cache replacement
1740 policies see http://www.hpl.hp.com/techreports/1999/HPL-1999-69.html
1741 and http://fog.hpl.external.hp.com/techreports/98/HPL-98-173.html.
1747 LOC: Config.cacheSwap
1751 cache_dir Type Directory-Name Fs-specific-data [options]
1753 You can specify multiple cache_dir lines to spread the
1754 cache among different disk partitions.
1756 Type specifies the kind of storage system to use. Only "ufs"
1757 is built by default. To enable any of the other storage systems
1758 see the --enable-storeio configure option.
1760 'Directory' is a top-level directory where cache swap
1761 files will be stored. If you want to use an entire disk
1762 for caching, this can be the mount-point directory.
1763 The directory must exist and be writable by the Squid
1764 process. Squid will NOT create this directory for you.
1768 "ufs" is the old well-known Squid storage format that has always
1771 cache_dir ufs Directory-Name Mbytes L1 L2 [options]
1773 'Mbytes' is the amount of disk space (MB) to use under this
1774 directory. The default is 100 MB. Change this to suit your
1775 configuration. Do NOT put the size of your disk drive here.
1776 Instead, if you want Squid to use the entire disk drive,
1777 subtract 20% and use that value.
1779 'Level-1' is the number of first-level subdirectories which
1780 will be created under the 'Directory'. The default is 16.
1782 'Level-2' is the number of second-level subdirectories which
1783 will be created under each first-level directory. The default
1786 The aufs store type:
1788 "aufs" uses the same storage format as "ufs", utilizing
1789 POSIX-threads to avoid blocking the main Squid process on
1790 disk-I/O. This was formerly known in Squid as async-io.
1792 cache_dir aufs Directory-Name Mbytes L1 L2 [options]
1794 see argument descriptions under ufs above
1796 The diskd store type:
1798 "diskd" uses the same storage format as "ufs", utilizing a
1799 separate process to avoid blocking the main Squid process on
1802 cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n]
1804 see argument descriptions under ufs above
1806 Q1 specifies the number of unacknowledged I/O requests when Squid
1807 stops opening new files. If this many messages are in the queues,
1808 Squid won't open new files. Default is 64
1810 Q2 specifies the number of unacknowledged messages when Squid
1811 starts blocking. If this many messages are in the queues,
1812 Squid blocks until it receives some replies. Default is 72
1814 When Q1 < Q2 (the default), the cache directory is optimized
1815 for lower response time at the expense of a decrease in hit
1816 ratio. If Q1 > Q2, the cache directory is optimized for
1817 higher hit ratio at the expense of an increase in response
1820 The coss store type:
1822 block-size=n defines the "block size" for COSS cache_dir's.
1823 Squid uses file numbers as block numbers. Since file numbers
1824 are limited to 24 bits, the block size determines the maximum
1825 size of the COSS partition. The default is 512 bytes, which
1826 leads to a maximum cache_dir size of 512<<24, or 8 GB. Note
1827 you should not change the coss block size after Squid
1828 has written some objects to the cache_dir.
1830 The coss file store has changed from 2.5. Now it uses a file
1831 called 'stripe' in the directory names in the config - and
1832 this will be created by squid -z.
1836 no-store, no new objects should be stored to this cache_dir
1838 max-size=n, refers to the max object size this storedir supports.
1839 It is used to initially choose the storedir to dump the object.
1840 Note: To make optimal use of the max-size limits you should order
1841 the cache_dir lines with the smallest max-size value first and the
1842 ones with no max-size specification last.
1844 Note for coss, max-size must be less than COSS_MEMBUF_SZ,
1845 which can be changed with the --with-coss-membuf-size=N configure
1848 DEFAULT_IF_NONE: ufs @DEFAULT_SWAP_DIR@ 100 16 256
1852 NAME: store_dir_select_algorithm
1854 LOC: Config.store_dir_select_algorithm
1857 Set this to 'round-robin' as an alternative.
1860 NAME: max_open_disk_fds
1862 LOC: Config.max_open_disk_fds
1865 To avoid having disk as the I/O bottleneck Squid can optionally
1866 bypass the on-disk cache if more than this amount of disk file
1867 descriptors are open.
1869 A value of 0 indicates no limit.
1872 NAME: minimum_object_size
1876 LOC: Config.Store.minObjectSize
1878 Objects smaller than this size will NOT be saved on disk. The
1879 value is specified in kilobytes, and the default is 0 KB, which
1880 means there is no minimum.
1883 NAME: maximum_object_size
1887 LOC: Config.Store.maxObjectSize
1889 Objects larger than this size will NOT be saved on disk. The
1890 value is specified in kilobytes, and the default is 4MB. If
1891 you wish to get a high BYTES hit ratio, you should probably
1892 increase this (one 32 MB object hit counts for 3200 10KB
1893 hits). If you wish to increase speed more than your want to
1894 save bandwidth you should leave this low.
1896 NOTE: if using the LFUDA replacement policy you should increase
1897 this value to maximize the byte hit rate improvement of LFUDA!
1898 See replacement_policy below for a discussion of this policy.
1901 NAME: cache_swap_low
1902 COMMENT: (percent, 0-100)
1905 LOC: Config.Swap.lowWaterMark
1908 NAME: cache_swap_high
1909 COMMENT: (percent, 0-100)
1912 LOC: Config.Swap.highWaterMark
1915 The low- and high-water marks for cache object replacement.
1916 Replacement begins when the swap (disk) usage is above the
1917 low-water mark and attempts to maintain utilization near the
1918 low-water mark. As swap utilization gets close to high-water
1919 mark object eviction becomes more aggressive. If utilization is
1920 close to the low-water mark less replacement is done each time.
1922 Defaults are 90% and 95%. If you have a large cache, 5% could be
1923 hundreds of MB. If this is the case you may wish to set these
1924 numbers closer together.
1929 -----------------------------------------------------------------------------
1934 LOC: Config.Log.logformats
1939 logformat <name> <format specification>
1941 Defines an access log format.
1943 The <format specification> is a string with embedded % format codes
1945 % format codes all follow the same basic structure where all but
1946 the formatcode is optional. Output strings are automatically escaped
1947 as required according to their context and the output format
1948 modifiers are usually not needed, but can be specified if an explicit
1949 output format is desired.
1951 % ["|[|'|#] [-] [[0]width] [{argument}] formatcode
1953 " output in quoted string format
1954 [ output in squid text log format as used by log_mime_hdrs
1955 # output in URL quoted format
1959 width field width. If starting with 0 the
1960 output is zero padded
1961 {arg} argument such as header name etc
1965 >a Client source IP address
1967 >p Client source port
1968 <A Server IP address or peer name
1969 la Local IP address (http_port)
1970 lp Local port number (http_port)
1971 ts Seconds since epoch
1972 tu subsecond time (milliseconds)
1973 tl Local time. Optional strftime format argument
1974 default %d/%b/%Y:%H:%M:%S %z
1975 tg GMT time. Optional strftime format argument
1976 default %d/%b/%Y:%H:%M:%S %z
1977 tr Response time (milliseconds)
1978 >h Request header. Optional header name argument
1979 on the format header[:[separator]element]
1980 <h Reply header. Optional header name argument
1983 ul User name from authentication
1984 ui User name from ident
1985 us User name from SSL
1986 ue User name from external acl helper
1988 Ss Squid request status (TCP_MISS etc)
1989 Sh Squid hierarchy status (DEFAULT_PARENT etc)
1990 mt MIME content type
1991 rm Request method (GET/POST etc)
1993 rp Request URL-Path excluding hostname
1994 rv Request protocol version
1995 et Tag returned by external acl
1996 ea Log string returned by external acl
1997 <st Reply size including HTTP headers
1998 <sH Reply high offset sent
1999 <sS Upstream object size
2000 % a literal % character
2002 logformat squid %ts.%03tu %6tr %>a %Ss/%03Hs %<st %rm %ru %un %Sh/%<A %mt
2003 logformat squidmime %ts.%03tu %6tr %>a %Ss/%03Hs %<st %rm %ru %un %Sh/%<A %mt [%>h] [%<h]
2004 logformat common %>a %ui %un [%tl] "%rm %ru HTTP/%rv" %Hs %<st %Ss:%Sh
2005 logformat combined %>a %ui %un [%tl] "%rm %ru HTTP/%rv" %Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
2008 NAME: access_log cache_access_log
2010 LOC: Config.Log.accesslogs
2013 These files log client request activities. Has a line every HTTP or
2014 ICP request. The format is:
2015 access_log <filepath> [<logformat name> [acl acl ...]]
2016 access_log none [acl acl ...]]
2018 Will log to the specified file using the specified format (which
2019 must be defined in a logformat directive) those entries which match
2020 ALL the acl's specified (which must be defined in acl clauses).
2021 If no acl is specified, all requests will be logged to this file.
2023 To disable logging of a request use the filepath "none", in which case
2024 a logformat name should not be specified.
2026 To log the request via syslog specify a filepath of "syslog":
2028 access_log syslog[:facility.priority] [format [acl1 [acl2 ....]]]
2029 where facility could be any of:
2030 authpriv, daemon, local0 .. local7 or user.
2032 And priority could be any of:
2033 err, warning, notice, info, debug.
2035 access_log @DEFAULT_ACCESS_LOG@ squid
2041 LOC: Config.accessList.log
2043 COMMENT: allow|deny acl acl...
2045 This options allows you to control which requests gets logged
2046 to access.log (see access_log directive). Requests denied for
2047 logging will also not be accounted for in performance counters.
2052 DEFAULT: @DEFAULT_CACHE_LOG@
2055 Cache logging file. This is where general information about
2056 your cache's behavior goes. You can increase the amount of data
2057 logged to this file with the "debug_options" tag below.
2060 NAME: cache_store_log
2062 DEFAULT: @DEFAULT_STORE_LOG@
2063 LOC: Config.Log.store
2065 Logs the activities of the storage manager. Shows which
2066 objects are ejected from the cache, and which objects are
2067 saved and for how long. To disable, enter "none". There are
2068 not really utilities to analyze this data, so you can safely
2072 NAME: cache_swap_state cache_swap_log
2074 LOC: Config.Log.swap
2077 Location for the cache "swap.state" file. This index file holds
2078 the metadata of objects saved on disk. It is used to rebuild
2079 the cache during startup. Normally this file resides in each
2080 'cache_dir' directory, but you may specify an alternate
2081 pathname here. Note you must give a full filename, not just
2082 a directory. Since this is the index for the whole object
2083 list you CANNOT periodically rotate it!
2085 If %s can be used in the file name it will be replaced with a
2086 a representation of the cache_dir name where each / is replaced
2087 with '.'. This is needed to allow adding/removing cache_dir
2088 lines when cache_swap_log is being used.
2090 If have more than one 'cache_dir', and %s is not used in the name
2091 these swap logs will have names such as:
2097 The numbered extension (which is added automatically)
2098 corresponds to the order of the 'cache_dir' lines in this
2099 configuration file. If you change the order of the 'cache_dir'
2100 lines in this file, these index files will NOT correspond to
2101 the correct 'cache_dir' entry (unless you manually rename
2102 them). We recommend you do NOT use this option. It is
2103 better to keep these index files in each 'cache_dir' directory.
2106 NAME: logfile_rotate
2109 LOC: Config.Log.rotateNumber
2111 Specifies the number of logfile rotations to make when you
2112 type 'squid -k rotate'. The default is 10, which will rotate
2113 with extensions 0 through 9. Setting logfile_rotate to 0 will
2114 disable the file name rotation, but the logfiles are still closed
2115 and re-opened. This will enable you to rename the logfiles
2116 yourself just before sending the rotate signal.
2118 Note, the 'squid -k rotate' command normally sends a USR1
2119 signal to the running squid process. In certain situations
2120 (e.g. on Linux with Async I/O), USR1 is used for other
2121 purposes, so -k rotate uses another signal. It is best to get
2122 in the habit of using 'squid -k rotate' instead of 'kill -USR1
2126 NAME: emulate_httpd_log
2130 LOC: Config.onoff.common_log
2132 The Cache can emulate the log file format which many 'httpd'
2133 programs use. To disable/enable this emulation, set
2134 emulate_httpd_log to 'off' or 'on'. The default
2135 is to use the native log format since it includes useful
2136 information Squid-specific log analyzers use.
2139 NAME: log_ip_on_direct
2143 LOC: Config.onoff.log_ip_on_direct
2145 Log the destination IP address in the hierarchy log tag when going
2146 direct. Earlier Squid versions logged the hostname here. If you
2147 prefer the old way set this to off.
2152 DEFAULT: @DEFAULT_MIME_TABLE@
2153 LOC: Config.mimeTablePathname
2155 Pathname to Squid's MIME table. You shouldn't need to change
2156 this, but the default file contains examples and formatting
2157 information if you do.
2163 LOC: Config.onoff.log_mime_hdrs
2166 The Cache can record both the request and the response MIME
2167 headers for each HTTP transaction. The headers are encoded
2168 safely and will appear as two bracketed fields at the end of
2169 the access log (for either the native or httpd-emulated log
2170 formats). To enable this logging set log_mime_hdrs to 'on'.
2175 LOC: Config.Log.useragent
2177 IFDEF: USE_USERAGENT_LOG
2179 Squid will write the User-Agent field from HTTP requests
2180 to the filename specified here. By default useragent_log
2184 NAME: referer_log referrer_log
2186 LOC: Config.Log.referer
2188 IFDEF: USE_REFERER_LOG
2190 Squid will write the Referer field from HTTP requests to the
2191 filename specified here. By default referer_log is disabled.
2192 Note that "referer" is actually a misspelling of "referrer"
2193 however the misspelt version has been accepted into the HTTP RFCs
2199 DEFAULT: @DEFAULT_PID_FILE@
2200 LOC: Config.pidFilename
2202 A filename to write the process-id to. To disable, enter "none".
2208 LOC: Config.debugOptions
2210 Logging options are set as section,level where each source file
2211 is assigned a unique section. Lower levels result in less
2212 output, Full debugging (level 9) can result in a very large
2213 log file, so be careful. The magic word "ALL" sets debugging
2214 levels for all sections. We recommend normally running with
2222 LOC: Config.onoff.log_fqdn
2224 Turn this on if you wish to log fully qualified domain names
2225 in the access.log. To do this Squid does a DNS lookup of all
2226 IP's connecting to it. This can (in some situations) increase
2227 latency, which makes your cache seem slower for interactive
2231 NAME: client_netmask
2233 LOC: Config.Addrs.client_netmask
2234 DEFAULT: 255.255.255.255
2236 A netmask for client addresses in logfiles and cachemgr output.
2237 Change this to protect the privacy of your cache clients.
2238 A netmask of 255.255.255.0 will log all IP's in that range with
2239 the last digit set to '0'.
2246 LOC: Config.Log.forward
2248 Logs the server-side requests.
2250 This is currently work in progress.
2253 NAME: strip_query_terms
2255 LOC: Config.onoff.strip_query_terms
2258 By default, Squid strips query terms from requested URLs before
2259 logging. This protects your user's privacy.
2266 LOC: Config.onoff.buffered_logs
2268 cache.log log file is written with stdio functions, and as such
2269 it can be buffered or unbuffered. By default it will be unbuffered.
2270 Buffering it can speed up the writing slightly (though you are
2271 unlikely to need to worry unless you run with tons of debugging
2272 enabled in which case performance will suffer badly anyway..).
2275 NAME: netdb_filename
2277 DEFAULT: @DEFAULT_NETDB_FILE@
2278 LOC: Config.netdbFilename
2281 A filename where Squid stores it's netdb state between restarts.
2282 To disable, enter "none".
2286 OPTIONS FOR FTP GATEWAYING
2287 -----------------------------------------------------------------------------
2293 LOC: Config.Ftp.anon_user
2295 If you want the anonymous login password to be more informative
2296 (and enable the use of picky ftp servers), set this to something
2297 reasonable for your domain, like wwwuser@somewhere.net
2299 The reason why this is domainless by default is the
2300 request can be made on the behalf of a user in any domain,
2301 depending on how the cache is used.
2302 Some ftp server also validate the email address is valid
2303 (for example perl.com).
2306 NAME: ftp_list_width
2309 LOC: Config.Ftp.list_width
2311 Sets the width of ftp listings. This should be set to fit in
2312 the width of a standard browser. Setting this too small
2313 can cut off long filenames when browsing ftp sites.
2319 LOC: Config.Ftp.passive
2321 If your firewall does not allow Squid to use passive
2322 connections, turn off this option.
2325 NAME: ftp_sanitycheck
2328 LOC: Config.Ftp.sanitycheck
2330 For security and data integrity reasons Squid by default performs
2331 sanity checks of the addresses of FTP data connections ensure the
2332 data connection is to the requested server. If you need to allow
2333 FTP connections to servers using another IP address for the data
2334 connection turn this off.
2337 NAME: ftp_telnet_protocol
2340 LOC: Config.Ftp.telnet
2342 The FTP protocol is officially defined to use the telnet protocol
2343 as transport channel for the control connection. However, many
2344 implementations are broken and does not respect this aspect of
2347 If you have trouble accessing files with ASCII code 255 in the
2348 path or similar problems involving this ASCII code you can
2349 try setting this directive to off. If that helps, report to the
2350 operator of the FTP server in question that their FTP server
2351 is broken and does not follow the FTP standard.
2355 OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
2356 -----------------------------------------------------------------------------
2361 DEFAULT: @DEFAULT_DISKD@
2362 LOC: Config.Program.diskd
2364 Specify the location of the diskd executable.
2365 Note this is only useful if you have compiled in
2366 diskd as one of the store io modules.
2369 NAME: unlinkd_program
2372 DEFAULT: @DEFAULT_UNLINKD@
2373 LOC: Config.Program.unlinkd
2375 Specify the location of the executable for file deletion process.
2378 NAME: pinger_program
2380 DEFAULT: @DEFAULT_PINGER@
2381 LOC: Config.pinger.program
2384 Specify the location of the executable for the pinger process.
2390 LOC: Config.pinger.enable
2393 Control whether the pinger is active at run-time.
2394 Enables turning ICMP pinger on and off with a simple squid -k reconfigure.
2399 OPTIONS FOR URL REWRITING
2400 -----------------------------------------------------------------------------
2403 NAME: url_rewrite_program redirect_program
2405 LOC: Config.Program.redirect
2408 Specify the location of the executable for the URL rewriter.
2409 Since they can perform almost any function there isn't one included.
2411 For each requested URL rewriter will receive on line with the format
2413 URL <SP> client_ip "/" fqdn <SP> user <SP> method [<SP> kvpairs]<NL>
2415 In the future, the rewriter interface will be extended with
2416 key=value pairs ("kvpairs" shown above). Rewriter programs
2417 should be prepared to receive and possibly ignore additional
2418 whitespace-separated tokens on each input line.
2420 And the rewriter may return a rewritten URL. The other components of
2421 the request line does not need to be returned (ignored if they are).
2423 The rewriter can also indicate that a client-side redirect should
2424 be performed to the new URL. This is done by prefixing the returned
2425 URL with "301:" (moved permanently) or 302: (moved temporarily).
2427 By default, a URL rewriter is not used.
2430 NAME: url_rewrite_children redirect_children
2433 LOC: Config.redirectChildren
2435 The number of redirector processes to spawn. If you start
2436 too few Squid will have to wait for them to process a backlog of
2437 URLs, slowing it down. If you start too many they will use RAM
2438 and other system resources.
2441 NAME: url_rewrite_concurrency redirect_concurrency
2444 LOC: Config.redirectConcurrency
2446 The number of requests each redirector helper can handle in
2447 parallel. Defaults to 0 which indicates the redirector
2448 is a old-style single threaded redirector.
2451 NAME: url_rewrite_host_header redirect_rewrites_host_header
2454 LOC: Config.onoff.redir_rewrites_host
2456 By default Squid rewrites any Host: header in redirected
2457 requests. If you are running an accelerator this may
2458 not be a wanted effect of a redirector.
2460 WARNING: Entries are cached on the result of the URL rewriting
2461 process, so be careful if you have domain-virtual hosts.
2464 NAME: url_rewrite_access redirector_access
2467 LOC: Config.accessList.redirector
2469 If defined, this access list specifies which requests are
2470 sent to the redirector processes. By default all requests
2474 NAME: url_rewrite_bypass redirector_bypass
2476 LOC: Config.onoff.redirector_bypass
2479 When this is 'on', a request will not go through the
2480 redirector if all redirectors are busy. If this is 'off'
2481 and the redirector queue grows too large, Squid will exit
2482 with a FATAL error and ask you to increase the number of
2483 redirectors. You should only enable this if the redirectors
2484 are not critical to your caching system. If you use
2485 redirectors for access control, and you enable this option,
2486 users may have access to pages they should not
2487 be allowed to request.
2491 OPTIONS FOR TUNING THE CACHE
2492 -----------------------------------------------------------------------------
2495 NAME: cache no_cache
2498 LOC: Config.accessList.noCache
2500 A list of ACL elements which, if matched, cause the request to
2501 not be satisfied from the cache and the reply to not be cached.
2502 In other words, use this to force certain objects to never be cached.
2504 You must use the word 'DENY' to indicate the ACL names which should
2507 Default is to allow all to be cached
2509 #We recommend you to use the following two lines.
2510 acl QUERY urlpath_regex cgi-bin \?
2515 NAME: refresh_pattern
2516 TYPE: refreshpattern
2520 usage: refresh_pattern [-i] regex min percent max [options]
2522 By default, regular expressions are CASE-SENSITIVE. To make
2523 them case-insensitive, use the -i option.
2525 'Min' is the time (in minutes) an object without an explicit
2526 expiry time should be considered fresh. The recommended
2527 value is 0, any higher values may cause dynamic applications
2528 to be erroneously cached unless the application designer
2529 has taken the appropriate actions.
2531 'Percent' is a percentage of the objects age (time since last
2532 modification age) an object without explicit expiry time
2533 will be considered fresh.
2535 'Max' is an upper limit on how long objects without an explicit
2536 expiry time will be considered fresh.
2538 options: override-expire
2548 override-expire enforces min age even if the server
2549 sent a Expires: header. Doing this VIOLATES the HTTP
2550 standard. Enabling this feature could make you liable
2551 for problems which it causes.
2553 override-lastmod enforces min age even on objects
2554 that were modified recently.
2556 reload-into-ims changes client no-cache or ``reload''
2557 to If-Modified-Since requests. Doing this VIOLATES the
2558 HTTP standard. Enabling this feature could make you
2559 liable for problems which it causes.
2561 ignore-reload ignores a client no-cache or ``reload''
2562 header. Doing this VIOLATES the HTTP standard. Enabling
2563 this feature could make you liable for problems which
2566 ignore-no-cache ignores any ``Pragma: no-cache'' and
2567 ``Cache-control: no-cache'' headers received from a server.
2568 The HTTP RFC never allows the use of this (Pragma) header
2569 from a server, only a client, though plenty of servers
2572 ignore-no-store ignores any ``Cache-control: no-store''
2573 headers received from a server. Doing this VIOLATES
2574 the HTTP standard. Enabling this feature could make you
2575 liable for problems which it causes.
2577 ignore-private ignores any ``Cache-control: private''
2578 headers received from a server. Doing this VIOLATES
2579 the HTTP standard. Enabling this feature could make you
2580 liable for problems which it causes.
2582 ignore-auth caches responses to requests with authorization,
2583 as if the originserver had sent ``Cache-control: public''
2584 in the response header. Doing this VIOLATES the HTTP standard.
2585 Enabling this feature could make you liable for problems which
2588 refresh-ims causes squid to contact the origin server
2589 when a client issues an If-Modified-Since request. This
2590 ensures that the client will receive an updated version
2591 if one is available.
2593 Basically a cached object is:
2595 FRESH if expires < now, else STALE
2597 FRESH if lm-factor < percent, else STALE
2601 The refresh_pattern lines are checked in the order listed here.
2602 The first entry which matches is used. If none of the entries
2603 match the default will be used.
2605 Note, you must uncomment all the default lines if you want
2606 to change one. The default setting is only active if none is
2611 refresh_pattern ^ftp: 1440 20% 10080
2612 refresh_pattern ^gopher: 1440 0% 1440
2613 refresh_pattern . 0 20% 4320
2617 NAME: quick_abort_min
2621 LOC: Config.quickAbort.min
2624 NAME: quick_abort_max
2628 LOC: Config.quickAbort.max
2631 NAME: quick_abort_pct
2635 LOC: Config.quickAbort.pct
2637 The cache by default continues downloading aborted requests
2638 which are almost completed (less than 16 KB remaining). This
2639 may be undesirable on slow (e.g. SLIP) links and/or very busy
2640 caches. Impatient users may tie up file descriptors and
2641 bandwidth by repeatedly requesting and immediately aborting
2644 When the user aborts a request, Squid will check the
2645 quick_abort values to the amount of data transfered until
2648 If the transfer has less than 'quick_abort_min' KB remaining,
2649 it will finish the retrieval.
2651 If the transfer has more than 'quick_abort_max' KB remaining,
2652 it will abort the retrieval.
2654 If more than 'quick_abort_pct' of the transfer has completed,
2655 it will finish the retrieval.
2657 If you do not want any retrieval to continue after the client
2658 has aborted, set both 'quick_abort_min' and 'quick_abort_max'
2661 If you want retrievals to always continue if they are being
2662 cached set 'quick_abort_min' to '-1 KB'.
2665 NAME: read_ahead_gap
2666 COMMENT: buffer-size
2668 LOC: Config.readAheadGap
2671 The amount of data the cache will buffer ahead of what has been
2672 sent to the client when retrieving an object from another server.
2678 LOC: Config.negativeTtl
2681 Time-to-Live (TTL) for failed requests. Certain types of
2682 failures (such as "connection refused" and "404 Not Found") are
2683 negatively-cached for a configurable amount of time. The
2684 default is 5 minutes. Note that this is different from
2685 negative caching of DNS lookups.
2688 NAME: positive_dns_ttl
2691 LOC: Config.positiveDnsTtl
2694 Upper limit on how long Squid will cache positive DNS responses.
2695 Default is 6 hours (360 minutes). This directive must be set
2696 larger than negative_dns_ttl.
2699 NAME: negative_dns_ttl
2702 LOC: Config.negativeDnsTtl
2705 Time-to-Live (TTL) for negative caching of failed DNS lookups.
2706 This also sets the lower cache limit on positive lookups.
2707 Minimum value is 1 second, and it is not recommendable to go
2708 much below 10 seconds.
2711 NAME: range_offset_limit
2714 LOC: Config.rangeOffsetLimit
2717 Sets a upper limit on how far into the the file a Range request
2718 may be to cause Squid to prefetch the whole file. If beyond this
2719 limit Squid forwards the Range request as it is and the result
2722 This is to stop a far ahead range request (lets say start at 17MB)
2723 from making Squid fetch the whole object up to that point before
2724 sending anything to the client.
2726 A value of -1 causes Squid to always fetch the object from the
2727 beginning so it may cache the result. (2.0 style)
2729 A value of 0 causes Squid to never fetch more than the
2730 client requested. (default)
2733 NAME: minimum_expiry_time
2736 LOC: Config.minimum_expiry_time
2739 The minimum caching time according to (Expires - Date)
2740 Headers Squid honors if the object can't be revalidated
2741 defaults to 60 seconds. In reverse proxy enorinments it
2742 might be desirable to honor shorter object lifetimes. It
2743 is most likely better to make your server return a
2744 meaningful Last-Modified header however. In ESI environments
2745 where page fragments often have short lifetimes, this will
2746 often be best set to 0.
2749 NAME: store_avg_object_size
2753 LOC: Config.Store.avgObjectSize
2755 Average object size, used to estimate number of objects your
2756 cache can hold. The default is 13 KB.
2759 NAME: store_objects_per_bucket
2762 LOC: Config.Store.objectsPerBucket
2764 Target number of objects per bucket in the store hash table.
2765 Lowering this value increases the total number of buckets and
2766 also the storage maintenance rate. The default is 20.
2771 -----------------------------------------------------------------------------
2774 NAME: request_header_max_size
2778 LOC: Config.maxRequestHeaderSize
2780 This specifies the maximum size for HTTP headers in a request.
2781 Request headers are usually relatively small (about 512 bytes).
2782 Placing a limit on the request header size will catch certain
2783 bugs (for example with persistent connections) and possibly
2784 buffer-overflow or denial-of-service attacks.
2787 NAME: reply_header_max_size
2791 LOC: Config.maxReplyHeaderSize
2793 This specifies the maximum size for HTTP headers in a reply.
2794 Reply headers are usually relatively small (about 512 bytes).
2795 Placing a limit on the reply header size will catch certain
2796 bugs (for example with persistent connections) and possibly
2797 buffer-overflow or denial-of-service attacks.
2800 NAME: request_body_max_size
2804 LOC: Config.maxRequestBodySize
2806 This specifies the maximum size for an HTTP request body.
2807 In other words, the maximum size of a PUT/POST request.
2808 A user who attempts to send a request with a body larger
2809 than this limit receives an "Invalid Request" error message.
2810 If you set this parameter to a zero (the default), there will
2811 be no limit imposed.
2817 LOC: Config.accessList.brokenPosts
2819 A list of ACL elements which, if matched, causes Squid to send
2820 an extra CRLF pair after the body of a PUT/POST request.
2822 Some HTTP servers has broken implementations of PUT/POST,
2823 and rely on an extra CRLF pair sent by some WWW clients.
2825 Quote from RFC2616 section 4.1 on this matter:
2827 Note: certain buggy HTTP/1.0 client implementations generate an
2828 extra CRLF's after a POST request. To restate what is explicitly
2829 forbidden by the BNF, an HTTP/1.1 client must not preface or follow
2830 a request with an extra CRLF.
2833 acl buggy_server url_regex ^http://....
2834 broken_posts allow buggy_server
2838 IFDEF: HTTP_VIOLATIONS
2842 LOC: Config.onoff.via
2844 If set (default), Squid will include a Via header in requests and
2845 replies as required by RFC2616.
2851 LOC: Config.onoff.ie_refresh
2854 Microsoft Internet Explorer up until version 5.5 Service
2855 Pack 1 has an issue with transparent proxies, wherein it
2856 is impossible to force a refresh. Turning this on provides
2857 a partial fix to the problem, by causing all IMS-REFRESH
2858 requests from older IE versions to check the origin server
2859 for fresh content. This reduces hit ratio by some amount
2860 (~10% in my experience), but allows users to actually get
2861 fresh content when they want it. Note because Squid
2862 cannot tell if the user is using 5.5 or 5.5SP1, the behavior
2863 of 5.5 is unchanged from old versions of Squid (i.e. a
2864 forced refresh is impossible). Newer versions of IE will,
2865 hopefully, continue to have the new behavior and will be
2866 handled based on that assumption. This option defaults to
2867 the old Squid behavior, which is better for hit ratios but
2868 worse for clients using IE, if they need to be able to
2869 force fresh content.
2872 NAME: vary_ignore_expire
2875 LOC: Config.onoff.vary_ignore_expire
2878 Many HTTP servers supporting Vary gives such objects
2879 immediate expiry time with no cache-control header
2880 when requested by a HTTP/1.0 client. This option
2881 enables Squid to ignore such expiry times until
2882 HTTP/1.1 is fully implemented.
2883 WARNING: This may eventually cause some varying
2884 objects not intended for caching to get cached.
2887 NAME: extension_methods
2889 LOC: Config.ext_methods
2892 Squid only knows about standardized HTTP request methods.
2893 You can add up to 20 additional "extension" methods here.
2896 NAME: request_entities
2898 LOC: Config.onoff.request_entities
2901 Squid defaults to deny GET and HEAD requests with request entities,
2902 as the meaning of such requests are undefined in the HTTP standard
2903 even if not explicitly forbidden.
2905 Set this directive to on if you have clients which insists
2906 on sending request entities in GET or HEAD requests. But be warned
2907 that there is server software (both proxies and web servers) which
2908 can fail to properly process this kind of request which may make you
2909 vulnerable to cache pollution attacks if enabled.
2912 NAME: request_header_access
2913 IFDEF: HTTP_VIOLATIONS
2914 TYPE: http_header_access[]
2915 LOC: Config.request_header_access
2918 Usage: request_header_access header_name allow|deny [!]aclname ...
2920 WARNING: Doing this VIOLATES the HTTP standard. Enabling
2921 this feature could make you liable for problems which it
2924 This option replaces the old 'anonymize_headers' and the
2925 older 'http_anonymizer' option with something that is much
2926 more configurable. This new method creates a list of ACLs
2927 for each header, allowing you very fine-tuned header
2930 This option only applies to request headers, i.e., from the
2931 client to the server.
2933 You can only specify known headers for the header name.
2934 Other headers are reclassified as 'Other'. You can also
2935 refer to all the headers with 'All'.
2937 For example, to achieve the same behavior as the old
2938 'http_anonymizer standard' option, you should use:
2940 request_header_access From deny all
2941 request_header_access Referer deny all
2942 request_header_access Server deny all
2943 request_header_access User-Agent deny all
2944 request_header_access WWW-Authenticate deny all
2945 request_header_access Link deny all
2947 Or, to reproduce the old 'http_anonymizer paranoid' feature
2950 request_header_access Allow allow all
2951 request_header_access Authorization allow all
2952 request_header_access WWW-Authenticate allow all
2953 request_header_access Proxy-Authorization allow all
2954 request_header_access Proxy-Authenticate allow all
2955 request_header_access Cache-Control allow all
2956 request_header_access Content-Encoding allow all
2957 request_header_access Content-Length allow all
2958 request_header_access Content-Type allow all
2959 request_header_access Date allow all
2960 request_header_access Expires allow all
2961 request_header_access Host allow all
2962 request_header_access If-Modified-Since allow all
2963 request_header_access Last-Modified allow all
2964 request_header_access Location allow all
2965 request_header_access Pragma allow all
2966 request_header_access Accept allow all
2967 request_header_access Accept-Charset allow all
2968 request_header_access Accept-Encoding allow all
2969 request_header_access Accept-Language allow all
2970 request_header_access Content-Language allow all
2971 request_header_access Mime-Version allow all
2972 request_header_access Retry-After allow all
2973 request_header_access Title allow all
2974 request_header_access Connection allow all
2975 request_header_access Proxy-Connection allow all
2976 request_header_access All deny all
2978 although many of those are HTTP reply headers, and so should be
2979 controlled with the reply_header_access directive.
2981 By default, all headers are allowed (no anonymizing is
2985 NAME: reply_header_access
2986 IFDEF: HTTP_VIOLATIONS
2987 TYPE: http_header_access[]
2988 LOC: Config.reply_header_access
2991 Usage: reply_header_access header_name allow|deny [!]aclname ...
2993 WARNING: Doing this VIOLATES the HTTP standard. Enabling
2994 this feature could make you liable for problems which it
2997 This option only applies to reply headers, i.e., from the
2998 server to the client.
3000 This is the same as request_header_access, but in the other
3003 This option replaces the old 'anonymize_headers' and the
3004 older 'http_anonymizer' option with something that is much
3005 more configurable. This new method creates a list of ACLs
3006 for each header, allowing you very fine-tuned header
3009 You can only specify known headers for the header name.
3010 Other headers are reclassified as 'Other'. You can also
3011 refer to all the headers with 'All'.
3013 For example, to achieve the same behavior as the old
3014 'http_anonymizer standard' option, you should use:
3016 reply_header_access From deny all
3017 reply_header_access Referer deny all
3018 reply_header_access Server deny all
3019 reply_header_access User-Agent deny all
3020 reply_header_access WWW-Authenticate deny all
3021 reply_header_access Link deny all
3023 Or, to reproduce the old 'http_anonymizer paranoid' feature
3026 reply_header_access Allow allow all
3027 reply_header_access Authorization allow all
3028 reply_header_access WWW-Authenticate allow all
3029 reply_header_access Proxy-Authorization allow all
3030 reply_header_access Proxy-Authenticate allow all
3031 reply_header_access Cache-Control allow all
3032 reply_header_access Content-Encoding allow all
3033 reply_header_access Content-Length allow all
3034 reply_header_access Content-Type allow all
3035 reply_header_access Date allow all
3036 reply_header_access Expires allow all
3037 reply_header_access Host allow all
3038 reply_header_access If-Modified-Since allow all
3039 reply_header_access Last-Modified allow all
3040 reply_header_access Location allow all
3041 reply_header_access Pragma allow all
3042 reply_header_access Accept allow all
3043 reply_header_access Accept-Charset allow all
3044 reply_header_access Accept-Encoding allow all
3045 reply_header_access Accept-Language allow all
3046 reply_header_access Content-Language allow all
3047 reply_header_access Mime-Version allow all
3048 reply_header_access Retry-After allow all
3049 reply_header_access Title allow all
3050 reply_header_access Connection allow all
3051 reply_header_access Proxy-Connection allow all
3052 reply_header_access All deny all
3054 although the HTTP request headers won't be usefully controlled
3055 by this directive -- see request_header_access for details.
3057 By default, all headers are allowed (no anonymizing is
3061 NAME: header_replace
3062 IFDEF: HTTP_VIOLATIONS
3063 TYPE: http_header_replace[]
3064 LOC: Config.request_header_access
3067 Usage: header_replace header_name message
3068 Example: header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
3070 This option allows you to change the contents of headers
3071 denied with header_access above, by replacing them with
3072 some fixed string. This replaces the old fake_user_agent
3075 This only applies to request headers, not reply headers.
3077 By default, headers are removed if denied.
3080 NAME: relaxed_header_parser
3081 COMMENT: on|off|warn
3083 LOC: Config.onoff.relaxed_header_parser
3086 In the default "on" setting Squid accepts certain forms
3087 of non-compliant HTTP messages where it is unambiguous
3088 what the sending application intended even if the message
3089 is not correctly formatted. The messages is then normalized
3090 to the correct form when forwarded by Squid.
3092 If set to "warn" then a warning will be emitted in cache.log
3093 each time such HTTP error is encountered.
3095 If set to "off" then such HTTP errors will cause the request
3096 or response to be rejected.
3101 -----------------------------------------------------------------------------
3104 NAME: forward_timeout
3107 LOC: Config.Timeout.forward
3110 This parameter specifies how long Squid should at most attempt in
3111 finding a forwarding path for the request before giving up.
3114 NAME: connect_timeout
3117 LOC: Config.Timeout.connect
3120 This parameter specifies how long to wait for the TCP connect to
3121 the requested server or peer to complete before Squid should
3122 attempt to find another path where to forward the request.
3125 NAME: peer_connect_timeout
3128 LOC: Config.Timeout.peer_connect
3131 This parameter specifies how long to wait for a pending TCP
3132 connection to a peer cache. The default is 30 seconds. You
3133 may also set different timeout values for individual neighbors
3134 with the 'connect-timeout' option on a 'cache_peer' line.
3140 LOC: Config.Timeout.read
3143 The read_timeout is applied on server-side connections. After
3144 each successful read(), the timeout will be extended by this
3145 amount. If no data is read again after this amount of time,
3146 the request is aborted and logged with ERR_READ_TIMEOUT. The
3147 default is 15 minutes.
3150 NAME: request_timeout
3152 LOC: Config.Timeout.request
3155 How long to wait for an HTTP request after initial
3156 connection establishment.
3159 NAME: persistent_request_timeout
3161 LOC: Config.Timeout.persistent_request
3164 How long to wait for the next HTTP request on a persistent
3165 connection after the previous request completes.
3168 NAME: client_lifetime
3171 LOC: Config.Timeout.lifetime
3174 The maximum amount of time a client (browser) is allowed to
3175 remain connected to the cache process. This protects the Cache
3176 from having a lot of sockets (and hence file descriptors) tied up
3177 in a CLOSE_WAIT state from remote clients that go away without
3178 properly shutting down (either because of a network failure or
3179 because of a poor client implementation). The default is one
3182 NOTE: The default value is intended to be much larger than any
3183 client would ever need to be connected to your cache. You
3184 should probably change client_lifetime only as a last resort.
3185 If you seem to have many client connections tying up
3186 filedescriptors, we recommend first tuning the read_timeout,
3187 request_timeout, persistent_request_timeout and quick_abort values.
3190 NAME: half_closed_clients
3192 LOC: Config.onoff.half_closed_clients
3195 Some clients may shutdown the sending side of their TCP
3196 connections, while leaving their receiving sides open. Sometimes,
3197 Squid can not tell the difference between a half-closed and a
3198 fully-closed TCP connection. By default, half-closed client
3199 connections are kept open until a read(2) or write(2) on the
3200 socket returns an error. Change this option to 'off' and Squid
3201 will immediately close client connections when read(2) returns
3202 "no more data to read."
3207 LOC: Config.Timeout.pconn
3210 Timeout for idle persistent connections to servers and other
3217 LOC: Config.Timeout.ident
3220 Maximum time to wait for IDENT lookups to complete.
3222 If this is too high, and you enabled IDENT lookups from untrusted
3223 users, you might be susceptible to denial-of-service by having
3224 many ident requests going at once.
3227 NAME: shutdown_lifetime
3230 LOC: Config.shutdownLifetime
3233 When SIGTERM or SIGHUP is received, the cache is put into
3234 "shutdown pending" mode until all active sockets are closed.
3235 This value is the lifetime to set for all open descriptors
3236 during shutdown mode. Any active clients after this many
3237 seconds will receive a 'timeout' message.
3241 ADMINISTRATIVE PARAMETERS
3242 -----------------------------------------------------------------------------
3248 LOC: Config.adminEmail
3250 Email-address of local cache manager who will receive
3251 mail if the cache dies. The default is "webmaster."
3257 LOC: Config.EmailFrom
3259 From: email-address for mail sent when the cache dies.
3260 The default is to use 'appname@unique_hostname'.
3261 Default appname value is "squid", can be changed into
3262 src/globals.h before building squid.
3268 LOC: Config.EmailProgram
3270 Email program used to send mail if the cache dies.
3271 The default is "mail". The specified program must comply
3272 with the standard Unix mail syntax:
3273 mail-program recipient < mailfile
3275 Optional command line options can be specified.
3278 NAME: cache_effective_user
3280 DEFAULT: @DEFAULT_CACHE_EFFECTIVE_USER@
3281 LOC: Config.effectiveUser
3283 If you start Squid as root, it will change its effective/real
3284 UID/GID to the user specified below. The default is to change
3285 to UID of @DEFAULT_CACHE_EFFECTIVE_USER@.
3286 see also; cache_effective_group
3289 NAME: cache_effective_group
3292 LOC: Config.effectiveGroup
3294 Squid sets the GID to the effective user's default group ID
3295 (taken from the password file) and supplementary group list
3296 from the groups membership.
3298 If you want Squid to run with a specific GID regardless of
3299 the group memberships of the effective user then set this
3300 to the group (or GID) you want Squid to run as. When set
3301 all other group privileges of the effective user are ignored
3302 and only this GID is effective. If Squid is not started as
3303 root the user starting Squid MUST be member of the specified
3306 This option is not recommended by the Squid Team.
3307 Our preference is for administrators to configure a secure
3308 user account for squid with UID/GID matching system policies.
3311 NAME: httpd_suppress_version_string
3315 LOC: Config.onoff.httpd_suppress_version_string
3317 Suppress Squid version string info in HTTP headers and HTML error pages.
3320 NAME: visible_hostname
3322 LOC: Config.visibleHostname
3325 If you want to present a special hostname in error messages, etc,
3326 define this. Otherwise, the return value of gethostname()
3327 will be used. If you have multiple caches in a cluster and
3328 get errors about IP-forwarding you must set them to have individual
3329 names with this setting.
3332 NAME: unique_hostname
3334 LOC: Config.uniqueHostname
3337 If you want to have multiple machines with the same
3338 'visible_hostname' you must give each machine a different
3339 'unique_hostname' so forwarding loops can be detected.
3342 NAME: hostname_aliases
3344 LOC: Config.hostnameAliases
3347 A list of other DNS names your cache has.
3351 OPTIONS FOR THE CACHE REGISTRATION SERVICE
3352 -----------------------------------------------------------------------------
3354 This section contains parameters for the (optional) cache
3355 announcement service. This service is provided to help
3356 cache administrators locate one another in order to join or
3357 create cache hierarchies.
3359 An 'announcement' message is sent (via UDP) to the registration
3360 service by Squid. By default, the announcement message is NOT
3361 SENT unless you enable it with 'announce_period' below.
3363 The announcement message includes your hostname, plus the
3364 following information from this configuration file:
3370 All current information is processed regularly and made
3371 available on the Web at http://www.ircache.net/Cache/Tracker/.
3374 NAME: announce_period
3376 LOC: Config.Announce.period
3379 This is how frequently to send cache announcements. The
3380 default is `0' which disables sending the announcement
3383 To enable announcing your cache, just uncomment the line
3387 #To enable announcing your cache, just uncomment the line below.
3388 #announce_period 1 day
3394 DEFAULT: tracker.ircache.net
3395 LOC: Config.Announce.host
3401 LOC: Config.Announce.file
3407 LOC: Config.Announce.port
3409 announce_host and announce_port set the hostname and port
3410 number where the registration message will be sent.
3412 Hostname will default to 'tracker.ircache.net' and port will
3413 default default to 3131. If the 'filename' argument is given,
3414 the contents of that file will be included in the announce
3419 HTTPD-ACCELERATOR OPTIONS
3420 -----------------------------------------------------------------------------
3423 NAME: httpd_accel_surrogate_id
3424 IFDEF: USE_SQUID_ESI
3426 LOC: Config.Accel.surrogate_id
3429 Surrogates (http://www.esi.org/architecture_spec_1.0.html)
3430 need an identification token to allow control targeting. Because
3431 a farm of surrogates may all perform the same tasks, they may share
3432 an identification token.
3435 NAME: http_accel_surrogate_remote
3436 IFDEF: USE_SQUID_ESI
3440 LOC: Config.onoff.surrogate_is_remote
3442 Remote surrogates (such as those in a CDN) honour Surrogate-Control: no-store-remote.
3443 Set this to on to have squid behave as a remote surrogate.
3447 IFDEF: USE_SQUID_ESI
3448 COMMENT: libxml2|expat|custom
3450 LOC: ESIParser::Type
3453 ESI markup is not strictly XML compatible. The custom ESI parser
3454 will give higher performance, but cannot handle non ASCII character
3459 DELAY POOL PARAMETERS
3460 -----------------------------------------------------------------------------
3464 TYPE: delay_pool_count
3469 This represents the number of delay pools to be used. For example,
3470 if you have one class 2 delay pool and one class 3 delays pool, you
3471 have a total of 2 delay pools.
3475 TYPE: delay_pool_class
3480 This defines the class of each delay pool. There must be exactly one
3481 delay_class line for each delay pool. For example, to define two
3482 delay pools, one of class 2 and one of class 3, the settings above
3486 delay_pools 4 # 4 delay pools
3487 delay_class 1 2 # pool 1 is a class 2 pool
3488 delay_class 2 3 # pool 2 is a class 3 pool
3489 delay_class 3 4 # pool 3 is a class 4 pool
3490 delay_class 4 5 # pool 4 is a class 5 pool
3492 The delay pool classes are:
3494 class 1 Everything is limited by a single aggregate
3497 class 2 Everything is limited by a single aggregate
3498 bucket as well as an "individual" bucket chosen
3499 from bits 25 through 32 of the IP address.
3501 class 3 Everything is limited by a single aggregate
3502 bucket as well as a "network" bucket chosen
3503 from bits 17 through 24 of the IP address and a
3504 "individual" bucket chosen from bits 17 through
3505 32 of the IP address.
3507 class 4 Everything in a class 3 delay pool, with an
3508 additional limit on a per user basis. This
3509 only takes effect if the username is established
3510 in advance - by forcing authentication in your
3513 class 5 Requests are grouped according their tag (see
3514 external_acl's tag= reply).
3516 NOTE: If an IP address is a.b.c.d
3517 -> bits 25 through 32 are "d"
3518 -> bits 17 through 24 are "c"
3519 -> bits 17 through 32 are "c * 256 + d"
3523 TYPE: delay_pool_access
3528 This is used to determine which delay pool a request falls into.
3530 delay_access is sorted per pool and the matching starts with pool 1,
3531 then pool 2, ..., and finally pool N. The first delay pool where the
3532 request is allowed is selected for the request. If it does not allow
3533 the request to any pool then the request is not delayed (default).
3535 For example, if you want some_big_clients in delay
3536 pool 1 and lotsa_little_clients in delay pool 2:
3539 delay_access 1 allow some_big_clients
3540 delay_access 1 deny all
3541 delay_access 2 allow lotsa_little_clients
3542 delay_access 2 deny all
3543 delay_access 3 allow authenticated_clients
3546 NAME: delay_parameters
3547 TYPE: delay_pool_rates
3552 This defines the parameters for a delay pool. Each delay pool has
3553 a number of "buckets" associated with it, as explained in the
3554 description of delay_class. For a class 1 delay pool, the syntax is:
3556 delay_parameters pool aggregate
3558 For a class 2 delay pool:
3560 delay_parameters pool aggregate individual
3562 For a class 3 delay pool:
3564 delay_parameters pool aggregate network individual
3566 For a class 4 delay pool:
3568 delay_parameters pool aggregate network individual user
3570 For a class 5 delay pool:
3572 delay_parameters pool tag
3574 The variables here are:
3576 pool a pool number - ie, a number between 1 and the
3577 number specified in delay_pools as used in
3580 aggregate the "delay parameters" for the aggregate bucket
3583 individual the "delay parameters" for the individual
3584 buckets (class 2, 3).
3586 network the "delay parameters" for the network buckets
3589 user the delay parameters for the user buckets
3592 tag the delay parameters for the tag buckets
3595 A pair of delay parameters is written restore/maximum, where restore is
3596 the number of bytes (not bits - modem and network speeds are usually
3597 quoted in bits) per second placed into the bucket, and maximum is the
3598 maximum number of bytes which can be in the bucket at any time.
3600 For example, if delay pool number 1 is a class 2 delay pool as in the
3601 above example, and is being used to strictly limit each host to 64kbps
3602 (plus overheads), with no overall limit, the line is:
3604 delay_parameters 1 -1/-1 8000/8000
3606 Note that the figure -1 is used to represent "unlimited".
3608 And, if delay pool number 2 is a class 3 delay pool as in the above
3609 example, and you want to limit it to a total of 256kbps (strict limit)
3610 with each 8-bit network permitted 64kbps (strict limit) and each
3611 individual host permitted 4800bps with a bucket maximum size of 64kb
3612 to permit a decent web page to be downloaded at a decent speed
3613 (if the network is not being limited due to overuse) but slow down
3614 large downloads more significantly:
3616 delay_parameters 2 32000/32000 8000/8000 600/8000
3618 There must be one delay_parameters line for each delay pool.
3620 Finally, for a class 4 delay pool as in the example - each user will
3621 be limited to 128Kb no matter how many workstations they are logged into.:
3623 delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000
3626 NAME: delay_initial_bucket_level
3627 COMMENT: (percent, 0-100)
3631 LOC: Config.Delay.initial
3633 The initial bucket percentage is used to determine how much is put
3634 in each bucket when squid starts, is reconfigured, or first notices
3635 a host accessing it (in class 2 and class 3, individual hosts and
3636 networks only have buckets associated with them once they have been
3641 WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS
3642 -----------------------------------------------------------------------------
3647 LOC: Config.Wccp.router
3652 TYPE: IPAddress_list
3653 LOC: Config.Wccp2.router
3657 Use this option to define your WCCP ``home'' router for
3660 wccp_router supports a single WCCP(v1) router
3662 wccp2_router supports multiple WCCPv2 routers
3664 only one of the two may be used at the same time and defines
3665 which version of WCCP to use.
3670 LOC: Config.Wccp.version
3674 This directive is only relevant if you need to set up WCCP(v1)
3675 to some very old and end-of-life Cisco routers. In all other
3676 setups it must be left unset or at the default setting.
3677 It defines an internal version in the WCCP(v1) protocol,
3678 with version 4 being the officially documented protocol.
3680 According to some users, Cisco IOS 11.2 and earlier only
3681 support WCCP version 3. If you're using that or an earlier
3682 version of IOS, you may need to change this value to 3, otherwise
3683 do not specify this parameter.
3686 NAME: wccp2_rebuild_wait
3688 LOC: Config.Wccp2.rebuildwait
3692 If this is enabled Squid will wait for the cache dir rebuild to finish
3693 before sending the first wccp2 HereIAm packet
3696 NAME: wccp2_forwarding_method
3698 LOC: Config.Wccp2.forwarding_method
3702 WCCP2 allows the setting of forwarding methods between the
3703 router/switch and the cache. Valid values are as follows:
3705 1 - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
3706 2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
3708 Currently (as of IOS 12.4) cisco routers only support GRE.
3709 Cisco switches only support the L2 redirect assignment method.
3712 NAME: wccp2_return_method
3714 LOC: Config.Wccp2.return_method
3718 WCCP2 allows the setting of return methods between the
3719 router/switch and the cache for packets that the cache
3720 decides not to handle. Valid values are as follows:
3722 1 - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
3723 2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
3725 Currently (as of IOS 12.4) cisco routers only support GRE.
3726 Cisco switches only support the L2 redirect assignment.
3728 If the "ip wccp redirect exclude in" command has been
3729 enabled on the cache interface, then it is still safe for
3730 the proxy server to use a l2 redirect method even if this
3731 option is set to GRE.
3734 NAME: wccp2_assignment_method
3736 LOC: Config.Wccp2.assignment_method
3740 WCCP2 allows the setting of methods to assign the WCCP hash
3741 Valid values are as follows:
3746 As a general rule, cisco routers support the hash assignment method
3747 and cisco switches support the mask assignment method.
3752 LOC: Config.Wccp2.info
3754 DEFAULT_IF_NONE: standard 0
3757 WCCP2 allows for multiple traffic services. There are two
3758 types: "standard" and "dynamic". The standard type defines
3759 one service id - http (id 0). The dynamic service ids can be from
3760 51 to 255 inclusive. In order to use a dynamic service id
3761 one must define the type of traffic to be redirected; this is done
3762 using the wccp2_service_info option.
3764 The "standard" type does not require a wccp2_service_info option,
3765 just specifying the service id will suffice.
3767 MD5 service authentication can be enabled by adding
3768 "password=<password>" to the end of this service declaration.
3772 wccp2_service standard 0 # for the 'web-cache' standard service
3773 wccp2_service dynamic 80 # a dynamic service type which will be
3774 # fleshed out with subsequent options.
3775 wccp2_service standard 0 password=foo
3779 NAME: wccp2_service_info
3780 TYPE: wccp2_service_info
3781 LOC: Config.Wccp2.info
3785 Dynamic WCCPv2 services require further information to define the
3786 traffic you wish to have diverted.
3790 wccp2_service_info <id> protocol=<protocol> flags=<flag>,<flag>..
3791 priority=<priority> ports=<port>,<port>..
3793 The relevant WCCPv2 flags:
3794 + src_ip_hash, dst_ip_hash
3795 + source_port_hash, dest_port_hash
3796 + src_ip_alt_hash, dst_ip_alt_hash
3797 + src_port_alt_hash, dst_port_alt_hash
3800 The port list can be one to eight entries.
3804 wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source
3805 priority=240 ports=80
3807 Note: the service id must have been defined by a previous
3808 'wccp2_service dynamic <id>' entry.
3813 LOC: Config.Wccp2.weight
3817 Each cache server gets assigned a set of the destination
3818 hash proportional to their weight.
3823 LOC: Config.Wccp.address
3829 LOC: Config.Wccp2.address
3833 Use this option if you require WCCP to use a specific
3836 The default behavior is to not bind to any specific address.
3840 PERSISTENT CONNECTION HANDLING
3841 -----------------------------------------------------------------------------
3843 Also see "pconn_timeout" in the TIMEOUTS section
3846 NAME: client_persistent_connections
3848 LOC: Config.onoff.client_pconns
3852 NAME: server_persistent_connections
3854 LOC: Config.onoff.server_pconns
3857 Persistent connection support for clients and servers. By
3858 default, Squid uses persistent connections (when allowed)
3859 with its clients and servers. You can use these options to
3860 disable persistent connections with clients and/or servers.
3863 NAME: persistent_connection_after_error
3865 LOC: Config.onoff.error_pconns
3868 With this directive the use of persistent connections after
3869 HTTP errors can be disabled. Useful if you have clients
3870 who fail to handle errors on persistent connections proper.
3873 NAME: detect_broken_pconn
3875 LOC: Config.onoff.detect_broken_server_pconns
3878 Some servers have been found to incorrectly signal the use
3879 of HTTP/1.0 persistent connections even on replies not
3880 compatible, causing significant delays. This server problem
3881 has mostly been seen on redirects.
3883 By enabling this directive Squid attempts to detect such
3884 broken replies and automatically assume the reply is finished
3885 after 10 seconds timeout.
3889 CACHE DIGEST OPTIONS
3890 -----------------------------------------------------------------------------
3893 NAME: digest_generation
3894 IFDEF: USE_CACHE_DIGESTS
3896 LOC: Config.onoff.digest_generation
3899 This controls whether the server will generate a Cache Digest
3900 of its contents. By default, Cache Digest generation is
3901 enabled if Squid is compiled with --enable-cache-digests defined.
3904 NAME: digest_bits_per_entry
3905 IFDEF: USE_CACHE_DIGESTS
3907 LOC: Config.digest.bits_per_entry
3910 This is the number of bits of the server's Cache Digest which
3911 will be associated with the Digest entry for a given HTTP
3912 Method and URL (public key) combination. The default is 5.
3915 NAME: digest_rebuild_period
3916 IFDEF: USE_CACHE_DIGESTS
3919 LOC: Config.digest.rebuild_period
3922 This is the wait time between Cache Digest rebuilds.
3925 NAME: digest_rewrite_period
3927 IFDEF: USE_CACHE_DIGESTS
3929 LOC: Config.digest.rewrite_period
3932 This is the wait time between Cache Digest writes to
3936 NAME: digest_swapout_chunk_size
3939 IFDEF: USE_CACHE_DIGESTS
3940 LOC: Config.digest.swapout_chunk_size
3943 This is the number of bytes of the Cache Digest to write to
3944 disk at a time. It defaults to 4096 bytes (4KB), the Squid
3948 NAME: digest_rebuild_chunk_percentage
3949 COMMENT: (percent, 0-100)
3950 IFDEF: USE_CACHE_DIGESTS
3952 LOC: Config.digest.rebuild_chunk_percentage
3955 This is the percentage of the Cache Digest to be scanned at a
3956 time. By default it is set to 10% of the Cache Digest.
3961 -----------------------------------------------------------------------------
3966 LOC: Config.Port.snmp
3970 The port number where Squid listens for SNMP requests. To enable
3971 SNMP support set this to a suitable port number. Port number
3972 3401 is often used for the Squid SNMP agent. By default it's
3973 set to "0" (disabled)
3981 LOC: Config.accessList.snmp
3983 DEFAULT_IF_NONE: deny all
3986 Allowing or denying access to the SNMP port.
3988 All access to the agent is denied by default.
3991 snmp_access allow|deny [!]aclname ...
3994 snmp_access allow snmppublic localhost
3995 snmp_access deny all
3998 NAME: snmp_incoming_address
4000 LOC: Config.Addrs.snmp_incoming
4004 NAME: snmp_outgoing_address
4006 LOC: Config.Addrs.snmp_outgoing
4007 DEFAULT: 255.255.255.255
4010 Just like 'udp_incoming_address' above, but for the SNMP port.
4012 snmp_incoming_address is used for the SNMP socket receiving
4013 messages from SNMP agents.
4014 snmp_outgoing_address is used for SNMP packets returned to SNMP
4017 The default snmp_incoming_address (0.0.0.0) is to listen on all
4018 available network interfaces.
4020 If snmp_outgoing_address is set to 255.255.255.255 (the default)
4021 it will use the same socket as snmp_incoming_address. Only
4022 change this if you want to have SNMP replies sent using another
4023 address than where this Squid listens for SNMP queries.
4025 NOTE, snmp_incoming_address and snmp_outgoing_address can not have
4026 the same value since they both use port 3401.
4031 -----------------------------------------------------------------------------
4034 NAME: icp_port udp_port
4037 LOC: Config.Port.icp
4039 The port number where Squid sends and receives ICP queries to
4040 and from neighbor caches. The standard UDP port for ICP is 3130.
4041 Default is disabled (0).
4043 icp_port @DEFAULT_ICP_PORT@
4051 LOC: Config.Port.htcp
4053 The port number where Squid sends and receives HTCP queries to
4054 and from neighbor caches. To turn it on you want to set it to
4055 4827. By default it is set to "0" (disabled).
4061 NAME: log_icp_queries
4065 LOC: Config.onoff.log_udp
4067 If set, ICP queries are logged to access.log. You may wish
4068 do disable this if your ICP load is VERY high to speed things
4069 up or to simplify log analysis.
4072 NAME: udp_incoming_address
4074 LOC:Config.Addrs.udp_incoming
4077 udp_incoming_address is used for UDP packets received from other
4080 The default behavior is to not bind to any specific address.
4082 Only change this if you want to have all UDP queries received on
4083 a specific interface/address.
4085 NOTE: udp_incoming_address is used by the ICP, HTCP, and DNS
4086 modules. Altering it will affect all of them in the same manner.
4088 see also; udp_outgoing_address
4090 NOTE, udp_incoming_address and udp_outgoing_address can not
4091 have the same value since they both use the same port.
4094 NAME: udp_outgoing_address
4096 LOC: Config.Addrs.udp_outgoing
4097 DEFAULT: 255.255.255.255
4099 udp_outgoing_address is used for UDP packets sent out to other
4102 The default behavior is to not bind to any specific address.
4104 Instead it will use the same socket as udp_incoming_address.
4105 Only change this if you want to have UDP queries sent using another
4106 address than where this Squid listens for UDP queries from other
4109 NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS
4110 modules. Altering it will affect all of them in the same manner.
4112 see also; udp_incoming_address
4114 NOTE, udp_incoming_address and udp_outgoing_address can not
4115 have the same value since they both use the same port.
4122 LOC: Config.onoff.icp_hit_stale
4124 If you want to return ICP_HIT for stale cache objects, set this
4125 option to 'on'. If you have sibling relationships with caches
4126 in other administrative domains, this should be 'off'. If you only
4127 have sibling relationships with caches under your control,
4128 it is probably okay to set this to 'on'.
4129 If set to 'on', your siblings should use the option "allow-miss"
4130 on their cache_peer lines for connecting to you.
4133 NAME: minimum_direct_hops
4136 LOC: Config.minDirectHops
4138 If using the ICMP pinging stuff, do direct fetches for sites
4139 which are no more than this many hops away.
4142 NAME: minimum_direct_rtt
4145 LOC: Config.minDirectRtt
4147 If using the ICMP pinging stuff, do direct fetches for sites
4148 which are no more than this many rtt milliseconds away.
4154 LOC: Config.Netdb.low
4160 LOC: Config.Netdb.high
4162 The low and high water marks for the ICMP measurement
4163 database. These are counts, not percents. The defaults are
4164 900 and 1000. When the high water mark is reached, database
4165 entries will be deleted until the low mark is reached.
4168 NAME: netdb_ping_period
4170 LOC: Config.Netdb.period
4173 The minimum period for measuring a site. There will be at
4174 least this much delay between successive pings to the same
4175 network. The default is five minutes.
4182 LOC: Config.onoff.query_icmp
4184 If you want to ask your peers to include ICMP data in their ICP
4185 replies, enable this option.
4187 If your peer has configured Squid (during compilation) with
4188 '--enable-icmp' that peer will send ICMP pings to origin server
4189 sites of the URLs it receives. If you enable this option the
4190 ICP replies from that peer will include the ICMP data (if available).
4191 Then, when choosing a parent cache, Squid will choose the parent with
4192 the minimal RTT to the origin server. When this happens, the
4193 hierarchy field of the access.log will be
4194 "CLOSEST_PARENT_MISS". This option is off by default.
4197 NAME: test_reachability
4201 LOC: Config.onoff.test_reachability
4203 When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
4204 instead of ICP_MISS if the target host is NOT in the ICMP
4205 database, or has a zero RTT.
4208 NAME: icp_query_timeout
4212 LOC: Config.Timeout.icp_query
4214 Normally Squid will automatically determine an optimal ICP
4215 query timeout value based on the round-trip-time of recent ICP
4216 queries. If you want to override the value determined by
4217 Squid, set this 'icp_query_timeout' to a non-zero value. This
4218 value is specified in MILLISECONDS, so, to use a 2-second
4219 timeout (the old default), you would write:
4221 icp_query_timeout 2000
4224 NAME: maximum_icp_query_timeout
4228 LOC: Config.Timeout.icp_query_max
4230 Normally the ICP query timeout is determined dynamically. But
4231 sometimes it can lead to very large values (say 5 seconds).
4232 Use this option to put an upper limit on the dynamic timeout
4233 value. Do NOT use this option to always use a fixed (instead
4234 of a dynamic) timeout value. To set a fixed timeout see the
4235 'icp_query_timeout' directive.
4238 NAME: minimum_icp_query_timeout
4242 LOC: Config.Timeout.icp_query_min
4244 Normally the ICP query timeout is determined dynamically. But
4245 sometimes it can lead to very small timeouts, even lower than
4246 the normal latency variance on your link due to traffic.
4247 Use this option to put an lower limit on the dynamic timeout
4248 value. Do NOT use this option to always use a fixed (instead
4249 of a dynamic) timeout value. To set a fixed timeout see the
4250 'icp_query_timeout' directive.
4253 NAME: background_ping_rate
4257 LOC: Config.backgroundPingRate
4259 Controls how often the ICP pings are sent to siblings that
4260 have background-ping set.
4264 MULTICAST ICP OPTIONS
4265 -----------------------------------------------------------------------------
4270 LOC: Config.mcast_group_list
4273 This tag specifies a list of multicast groups which your server
4274 should join to receive multicasted ICP queries.
4276 NOTE! Be very careful what you put here! Be sure you
4277 understand the difference between an ICP _query_ and an ICP
4278 _reply_. This option is to be set only if you want to RECEIVE
4279 multicast queries. Do NOT set this option to SEND multicast
4280 ICP (use cache_peer for that). ICP replies are always sent via
4281 unicast, so this option does not affect whether or not you will
4282 receive replies from multicast group members.
4284 You must be very careful to NOT use a multicast address which
4285 is already in use by another group of caches.
4287 If you are unsure about multicast, please read the Multicast
4288 chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
4290 Usage: mcast_groups 239.128.16.128 224.0.1.20
4292 By default, Squid doesn't listen on any multicast groups.
4295 NAME: mcast_miss_addr
4296 IFDEF: MULTICAST_MISS_STREAM
4298 LOC: Config.mcast_miss.addr
4299 DEFAULT: 255.255.255.255
4301 If you enable this option, every "cache miss" URL will
4302 be sent out on the specified multicast address.
4304 Do not enable this option unless you are are absolutely
4305 certain you understand what you are doing.
4308 NAME: mcast_miss_ttl
4309 IFDEF: MULTICAST_MISS_STREAM
4311 LOC: Config.mcast_miss.ttl
4314 This is the time-to-live value for packets multicasted
4315 when multicasting off cache miss URLs is enabled. By
4316 default this is set to 'site scope', i.e. 16.
4319 NAME: mcast_miss_port
4320 IFDEF: MULTICAST_MISS_STREAM
4322 LOC: Config.mcast_miss.port
4325 This is the port number to be used in conjunction with
4329 NAME: mcast_miss_encode_key
4330 IFDEF: MULTICAST_MISS_STREAM
4332 LOC: Config.mcast_miss.encode_key
4333 DEFAULT: XXXXXXXXXXXXXXXX
4335 The URLs that are sent in the multicast miss stream are
4336 encrypted. This is the encryption key.
4339 NAME: mcast_icp_query_timeout
4343 LOC: Config.Timeout.mcast_icp_query
4345 For multicast peers, Squid regularly sends out ICP "probes" to
4346 count how many other peers are listening on the given multicast
4347 address. This value specifies how long Squid should wait to
4348 count all the replies. The default is 2000 msec, or 2
4353 INTERNAL ICON OPTIONS
4354 -----------------------------------------------------------------------------
4357 NAME: icon_directory
4359 LOC: Config.icons.directory
4360 DEFAULT: @DEFAULT_ICON_DIR@
4362 Where the icons are stored. These are normally kept in
4366 NAME: global_internal_static
4368 LOC: Config.onoff.global_internal_static
4371 This directive controls is Squid should intercept all requests for
4372 /squid-internal-static/ no matter which host the URL is requesting
4373 (default on setting), or if nothing special should be done for
4374 such URLs (off setting). The purpose of this directive is to make
4375 icons etc work better in complex cache hierarchies where it may
4376 not always be possible for all corners in the cache mesh to reach
4377 the server generating a directory listing.
4380 NAME: short_icon_urls
4382 LOC: Config.icons.use_short_names
4385 If this is enabled Squid will use short URLs for icons.
4386 If disabled it will revert to the old behavior of including
4387 it's own name and port in the URL.
4389 If you run a complex cache hierarchy with a mix of Squid and
4390 other proxies you may need to disable this directive.
4395 -----------------------------------------------------------------------------
4398 NAME: error_directory
4400 LOC: Config.errorDirectory
4401 DEFAULT: @DEFAULT_ERROR_DIR@
4403 If you wish to create your own versions of the default
4404 (English) error files, either to customize them to suit your
4405 language or company copy the template English files to another
4406 directory and point this tag at them.
4408 The squid developers are interested in making squid available in
4409 a wide variety of languages. If you are making translations for a
4410 langauge that Squid does not currently provide please consider
4411 contributing your translation back to the project.
4416 LOC: Config.errHtmlText
4419 HTML text to include in error messages. Make this a "mailto"
4420 URL to your admin address, or maybe just a link to your
4421 organizations Web page.
4423 To include this in your error messages, you must rewrite
4424 the error template files (found in the "errors" directory).
4425 Wherever you want the 'err_html_text' line to appear,
4426 insert a %L tag in the error template file.
4429 NAME: email_err_data
4432 LOC: Config.onoff.emailErrData
4435 If enabled, information about the occurred error will be
4436 included in the mailto links of the ERR pages (if %W is set)
4437 so that the email body contains the data.
4438 Syntax is <A HREF="mailto:%w%W">%w</A>
4443 LOC: Config.denyInfoList
4446 Usage: deny_info err_page_name acl
4447 or deny_info http://... acl
4448 Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
4450 This can be used to return a ERR_ page for requests which
4451 do not pass the 'http_access' rules. Squid remembers the last
4452 acl it evaluated in http_access, and if a 'deny_info' line exists
4453 for that ACL Squid returns a corresponding error page.
4455 The acl is typically the last acl on the http_access deny line which
4456 denied access. The exceptions to this rule are:
4457 - When Squid needs to request authentication credentials. It's then
4458 the first authentication related acl encountered
4459 - When none of the http_access lines matches. It's then the last
4460 acl processed on the last http_access line.
4462 You may use ERR_ pages that come with Squid or create your own pages
4463 and put them into the configured errors/ directory.
4465 Alternatively you can specify an error URL. The browsers will
4466 get redirected (302) to the specified URL. %s in the redirection
4467 URL will be replaced by the requested URL.
4469 Alternatively you can tell Squid to reset the TCP connection
4470 by specifying TCP_RESET.
4474 OPTIONS INFLUENCING REQUEST FORWARDING
4475 -----------------------------------------------------------------------------
4478 NAME: nonhierarchical_direct
4480 LOC: Config.onoff.nonhierarchical_direct
4483 By default, Squid will send any non-hierarchical requests
4484 (matching hierarchy_stoplist or not cacheable request type) direct
4487 If you set this to off, Squid will prefer to send these
4488 requests to parents.
4490 Note that in most configurations, by turning this off you will only
4491 add latency to these request without any improvement in global hit
4494 If you are inside an firewall see never_direct instead of
4500 LOC: Config.onoff.prefer_direct
4503 Normally Squid tries to use parents for most requests. If you for some
4504 reason like it to first try going direct and only use a parent if
4505 going direct fails set this to on.
4507 By combining nonhierarchical_direct off and prefer_direct on you
4508 can set up Squid to use a parent as a backup path if going direct
4511 Note: If you want Squid to use parents for all requests see
4512 the never_direct directive. prefer_direct only modifies how Squid
4513 acts on cacheable requests.
4518 LOC: Config.accessList.AlwaysDirect
4521 Usage: always_direct allow|deny [!]aclname ...
4523 Here you can use ACL elements to specify requests which should
4524 ALWAYS be forwarded by Squid to the origin servers without using
4525 any peers. For example, to always directly forward requests for
4526 local servers ignoring any parents or siblings you may have use
4529 acl local-servers dstdomain my.domain.net
4530 always_direct allow local-servers
4532 To always forward FTP requests directly, use
4535 always_direct allow FTP
4537 NOTE: There is a similar, but opposite option named
4538 'never_direct'. You need to be aware that "always_direct deny
4539 foo" is NOT the same thing as "never_direct allow foo". You
4540 may need to use a deny rule to exclude a more-specific case of
4541 some other rule. Example:
4543 acl local-external dstdomain external.foo.net
4544 acl local-servers dstdomain .foo.net
4545 always_direct deny local-external
4546 always_direct allow local-servers
4548 NOTE: If your goal is to make the client forward the request
4549 directly to the origin server bypassing Squid then this needs
4550 to be done in the client configuration. Squid configuration
4551 can only tell Squid how Squid should fetch the object.
4553 NOTE: This directive is not related to caching. The replies
4554 is cached as usual even if you use always_direct. To not cache
4555 the replies see no_cache.
4557 This option replaces some v1.1 options such as local_domain
4563 LOC: Config.accessList.NeverDirect
4566 Usage: never_direct allow|deny [!]aclname ...
4568 never_direct is the opposite of always_direct. Please read
4569 the description for always_direct if you have not already.
4571 With 'never_direct' you can use ACL elements to specify
4572 requests which should NEVER be forwarded directly to origin
4573 servers. For example, to force the use of a proxy for all
4574 requests, except those in your local domain use something like:
4576 acl local-servers dstdomain .foo.net
4577 acl all src 0.0.0.0/0.0.0.0
4578 never_direct deny local-servers
4579 never_direct allow all
4581 or if Squid is inside a firewall and there are local intranet
4582 servers inside the firewall use something like:
4584 acl local-intranet dstdomain .foo.net
4585 acl local-external dstdomain external.foo.net
4586 always_direct deny local-external
4587 always_direct allow local-intranet
4588 never_direct allow all
4590 This option replaces some v1.1 options such as inside_firewall
4595 ADVANCED NETWORKING OPTIONS
4596 -----------------------------------------------------------------------------
4599 NAME: incoming_icp_average
4602 LOC: Config.comm_incoming.icp_average
4605 NAME: incoming_http_average
4608 LOC: Config.comm_incoming.http_average
4611 NAME: incoming_dns_average
4614 LOC: Config.comm_incoming.dns_average
4617 NAME: min_icp_poll_cnt
4620 LOC: Config.comm_incoming.icp_min_poll
4623 NAME: min_dns_poll_cnt
4626 LOC: Config.comm_incoming.dns_min_poll
4629 NAME: min_http_poll_cnt
4632 LOC: Config.comm_incoming.http_min_poll
4634 Heavy voodoo here. I can't even believe you are reading this.
4635 Are you crazy? Don't even think about adjusting these unless
4636 you understand the algorithms in comm_select.c first!
4642 LOC: Config.accept_filter
4646 The name of an accept(2) filter to install on Squid's
4647 listen socket(s). This feature is perhaps specific to
4648 FreeBSD and requires support in the kernel.
4650 The 'httpready' filter delays delivering new connections
4651 to Squid until a full HTTP request has been received.
4652 See the accf_http(9) man page for details.
4654 The 'dataready' filter delays delivering new connections
4655 to Squid until there is some data to process.
4656 See the accf_dataready(9) man page for details.
4660 The 'data' filter delays delivering of new connections
4661 to Squid until there is some data to process by TCP_ACCEPT_DEFER.
4662 You may optionally specify a number of seconds to wait by
4663 'data=N' where N is the number of seconds. Defaults to 30
4664 if not specified. See the tcp(7) man page for details.
4667 accept_filter httpready
4672 NAME: tcp_recv_bufsize
4676 LOC: Config.tcpRcvBufsz
4678 Size of receive buffer to set for TCP sockets. Probably just
4679 as easy to change your kernel's default. Set to zero to use
4680 the default buffer size.
4685 -----------------------------------------------------------------------------
4692 LOC: TheICAPConfig.onoff
4695 If you want to enable the ICAP module support, set this to on.
4698 NAME: icap_connect_timeout
4701 LOC: TheICAPConfig.connect_timeout_raw
4704 This parameter specifies how long to wait for the TCP connect to
4705 the requested ICAP server to complete before giving up and either
4706 terminating the HTTP transaction or bypassing the failure.
4708 The default for optional services is peer_connect_timeout.
4709 The default for essential services is connect_timeout.
4710 If this option is explicitly set, its value applies to all services.
4713 NAME: icap_io_timeout
4717 LOC: TheICAPConfig.io_timeout_raw
4720 This parameter specifies how long to wait for an I/O activity on
4721 an established, active ICAP connection before giving up and
4722 either terminating the HTTP transaction or bypassing the
4725 The default is read_timeout.
4728 NAME: icap_service_failure_limit
4731 LOC: TheICAPConfig.service_failure_limit
4734 The limit specifies the number of failures that Squid tolerates
4735 when establishing a new TCP connection with an ICAP service. If
4736 the number of failures exceeds the limit, the ICAP service is
4737 not used for new ICAP requests until it is time to refresh its
4738 OPTIONS. The per-service failure counter is reset to zero each
4739 time Squid fetches new service OPTIONS.
4741 A negative value disables the limit. Without the limit, an ICAP
4742 service will not be considered down due to connectivity failures
4743 between ICAP OPTIONS requests.
4746 NAME: icap_service_revival_delay
4749 LOC: TheICAPConfig.service_revival_delay
4752 The delay specifies the number of seconds to wait after an ICAP
4753 OPTIONS request failure before requesting the options again. The
4754 failed ICAP service is considered "down" until fresh OPTIONS are
4757 The actual delay cannot be smaller than the hardcoded minimum
4758 delay of 30 seconds.
4761 NAME: icap_preview_enable
4765 LOC: TheICAPConfig.preview_enable
4768 The ICAP Preview feature allows the ICAP server to handle the
4769 HTTP message by looking only at the beginning of the message body
4770 or even without receiving the body at all. In some environments,
4771 previews greatly speedup ICAP processing.
4773 During an ICAP OPTIONS transaction, the server may tell Squid what
4774 HTTP messages should be previewed and how big the preview should be.
4775 Squid will not use Preview if the server did not request one.
4777 To disable ICAP Preview for all ICAP services, regardless of
4778 individual ICAP server OPTIONS responses, set this option to "off".
4780 icap_preview_enable off
4783 NAME: icap_preview_size
4786 LOC: TheICAPConfig.preview_size
4789 The default size of preview data to be sent to the ICAP server.
4790 -1 means no preview. This value might be overwritten on a per server
4791 basis by OPTIONS requests.
4794 NAME: icap_default_options_ttl
4797 LOC: TheICAPConfig.default_options_ttl
4800 The default TTL value for ICAP OPTIONS responses that don't have
4801 an Options-TTL header.
4804 NAME: icap_persistent_connections
4808 LOC: TheICAPConfig.reuse_connections
4811 Whether or not Squid should use persistent connections to
4815 NAME: icap_send_client_ip
4819 LOC: TheICAPConfig.send_client_ip
4822 This adds the header "X-Client-IP" to ICAP requests.
4825 NAME: icap_send_client_username
4829 LOC: TheICAPConfig.send_client_username
4832 This sends authenticated HTTP client username (if available) to
4833 the ICAP service. The username value is encoded based on the
4834 icap_client_username_encode option and is sent using the header
4835 specified by the icap_client_username_header option.
4838 NAME: icap_client_username_header
4841 LOC: TheICAPConfig.client_username_header
4842 DEFAULT: X-Client-Username
4844 ICAP request header name to use for send_client_username.
4847 NAME: icap_client_username_encode
4851 LOC: TheICAPConfig.client_username_encode
4854 Whether to base64 encode the authenticated client username.
4858 TYPE: icap_service_type
4863 Defines a single ICAP service
4865 icap_service servicename vectoring_point bypass service_url
4867 vectoring_point = reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
4868 This specifies at which point of transaction processing the
4869 ICAP service should be activated. *_postcache vectoring points
4870 are not yet supported.
4872 If set to 1, the ICAP service is treated as optional. If the
4873 service cannot be reached or malfunctions, Squid will try to
4874 ignore any errors and process the message as if the service
4875 was not enabled. No all ICAP errors can be bypassed.
4876 If set to 0, the ICAP service is treated as essential and all
4877 ICAP errors will result in an error page returned to the
4879 service_url = icap://servername:port/service
4882 icap_service service_1 reqmod_precache 0 icap://icap1.mydomain.net:1344/reqmod
4883 icap_service service_2 respmod_precache 0 icap://icap2.mydomain.net:1344/respmod
4887 TYPE: icap_class_type
4892 Defines an ICAP service chain. Eventually, multiple services per
4893 vectoring point will be supported. For now, please specify a single
4896 icap_class classname servicename
4899 icap_class class_1 service_1
4900 icap class class_2 service_1
4901 icap class class_3 service_3
4905 TYPE: icap_access_type
4910 Redirects a request through an ICAP service class, depending
4913 icap_access classname allow|deny [!]aclname...
4915 The icap_access statements are processed in the order they appear in
4916 this configuration file. If an access list matches, the processing stops.
4917 For an "allow" rule, the specified class is used for the request. A "deny"
4918 rule simply stops processing without using the class. You can also use the
4919 special classname "None".
4921 For backward compatibility, it is also possible to use services
4924 icap_access class_1 allow all
4929 -----------------------------------------------------------------------------
4932 NAME: check_hostnames
4935 LOC: Config.onoff.check_hostnames
4937 For security and stability reasons Squid can check
4938 hostnames for Internet standard RFC compliance. If you want
4939 Squid to perform these checks turn this directive on.
4942 NAME: allow_underscore
4945 LOC: Config.onoff.allow_underscore
4947 Underscore characters is not strictly allowed in Internet hostnames
4948 but nevertheless used by many sites. Set this to off if you want
4949 Squid to be strict about the standard.
4950 This check is performed only when check_hostnames is set to on.
4953 NAME: cache_dns_program
4955 IFDEF: USE_DNSSERVERS
4956 DEFAULT: @DEFAULT_DNSSERVER@
4957 LOC: Config.Program.dnsserver
4959 Specify the location of the executable for dnslookup process.
4964 IFDEF: USE_DNSSERVERS
4966 LOC: Config.dnsChildren
4968 The number of processes spawn to service DNS name lookups.
4969 For heavily loaded caches on large servers, you should
4970 probably increase this value to at least 10. The maximum
4971 is 32. The default is 5.
4973 You must have at least one dnsserver process.
4976 NAME: dns_retransmit_interval
4979 LOC: Config.Timeout.idns_retransmit
4980 IFDEF: !USE_DNSSERVERS
4982 Initial retransmit interval for DNS queries. The interval is
4983 doubled each time all configured DNS servers have been tried.
4990 LOC: Config.Timeout.idns_query
4991 IFDEF: !USE_DNSSERVERS
4993 DNS Query timeout. If no response is received to a DNS query
4994 within this time all DNS servers for the queried domain
4995 are assumed to be unavailable.
5002 LOC: Config.onoff.res_defnames
5004 Normally the RES_DEFNAMES resolver option is disabled
5005 (see res_init(3)). This prevents caches in a hierarchy
5006 from interpreting single-component hostnames locally. To allow
5007 Squid to handle single-component names, enable this option.
5010 NAME: dns_nameservers
5013 LOC: Config.dns_nameservers
5015 Use this if you want to specify a list of DNS name servers
5016 (IP addresses) to use instead of those given in your
5017 /etc/resolv.conf file.
5018 On Windows platforms, if no value is specified here or in
5019 the /etc/resolv.conf file, the list of DNS name servers are
5020 taken from the Windows registry, both static and dynamic DHCP
5021 configurations are supported.
5023 Example: dns_nameservers 10.0.0.1 192.172.0.4
5028 DEFAULT: @DEFAULT_HOSTS@
5029 LOC: Config.etcHostsPath
5031 Location of the host-local IP name-address associations
5032 database. Most Operating Systems have such a file on different
5034 - Un*X & Linux: /etc/hosts
5035 - Windows NT/2000: %SystemRoot%\system32\drivers\etc\hosts
5036 (%SystemRoot% value install default is c:\winnt)
5037 - Windows XP/2003: %SystemRoot%\system32\drivers\etc\hosts
5038 (%SystemRoot% value install default is c:\windows)
5039 - Windows 9x/Me: %windir%\hosts
5040 (%windir% value is usually c:\windows)
5041 - Cygwin: /etc/hosts
5043 The file contains newline-separated definitions, in the
5044 form ip_address_in_dotted_form name [name ...] names are
5045 whitespace-separated. Lines beginning with an hash (#)
5046 character are comments.
5048 The file is checked at startup and upon configuration.
5049 If set to 'none', it won't be checked.
5050 If append_domain is used, that domain will be added to
5051 domain-local (i.e. not containing any dot character) host
5057 LOC: Config.dns_testname_list
5059 DEFAULT_IF_NONE: netscape.com internic.net nlanr.net microsoft.com
5061 The DNS tests exit as soon as the first site is successfully looked up
5063 This test can be disabled with the -D command line option.
5068 LOC: Config.appendDomain
5071 Appends local domain name to hostnames without any dots in
5072 them. append_domain must begin with a period.
5074 Be warned there are now Internet names with no dots in
5075 them using only top-domain names, so setting this may
5076 cause some Internet sites to become unavailable.
5079 append_domain .yourdomain.com
5082 NAME: ignore_unknown_nameservers
5084 LOC: Config.onoff.ignore_unknown_nameservers
5087 By default Squid checks that DNS responses are received
5088 from the same IP addresses they are sent to. If they
5089 don't match, Squid ignores the response and writes a warning
5090 message to cache.log. You can allow responses from unknown
5091 nameservers by setting this option to 'off'.
5094 NAME: dns_v4_fallback
5097 LOC: Config.onoff.dns_require_A
5099 Standard practice with DNS is to lookup either A or AAAA records
5100 and use the results if it succeeds. Only looking up the other if
5101 the first attempt fails or otherwise produces no results.
5103 That policy however will cause squid to produce error pages for some
5104 servers that advertise AAAA but are unreachable over IPv6.
5106 If this is ON squid will always lookup both AAAA and A, using both.
5107 If this is OFF squid will lookup AAAA and only try A if none found.
5109 WARNING: There are some possibly unwanted side-effects with this on:
5110 *) Doubles the load placed by squid on the DNS network.
5111 *) May negatively impact connection delay times.
5115 COMMENT: (number of entries)
5118 LOC: Config.ipcache.size
5125 LOC: Config.ipcache.low
5132 LOC: Config.ipcache.high
5134 The size, low-, and high-water marks for the IP cache.
5137 NAME: fqdncache_size
5138 COMMENT: (number of entries)
5141 LOC: Config.fqdncache.size
5143 Maximum number of FQDN cache entries.
5148 -----------------------------------------------------------------------------
5155 LOC: Config.onoff.mem_pools
5157 If set, Squid will keep pools of allocated (but unused) memory
5158 available for future use. If memory is a premium on your
5159 system and you believe your malloc library outperforms Squid
5160 routines, disable this.
5163 NAME: memory_pools_limit
5167 LOC: Config.MemPools.limit
5169 Used only with memory_pools on:
5170 memory_pools_limit 50 MB
5172 If set to a non-zero value, Squid will keep at most the specified
5173 limit of allocated (but unused) memory in memory pools. All free()
5174 requests that exceed this limit will be handled by your malloc
5175 library. Squid does not pre-allocate any memory, just safe-keeps
5176 objects that otherwise would be free()d. Thus, it is safe to set
5177 memory_pools_limit to a reasonably high value even if your
5178 configuration will use less memory.
5180 If set to zero, Squid will keep all memory it can. That is, there
5181 will be no limit on the total amount of memory used for safe-keeping.
5183 To disable memory allocation optimization, do not set
5184 memory_pools_limit to 0. Set memory_pools to "off" instead.
5186 An overhead for maintaining memory pools is not taken into account
5187 when the limit is checked. This overhead is close to four bytes per
5188 object kept. However, pools may actually _save_ memory because of
5189 reduced memory thrashing in your malloc library.
5196 LOC: opt_forwarded_for
5198 If set, Squid will include your system's IP address or name
5199 in the HTTP requests it forwards. By default it looks like
5202 X-Forwarded-For: 192.1.2.3
5204 If you disable this, it will appear as
5206 X-Forwarded-For: unknown
5209 NAME: cachemgr_passwd
5210 TYPE: cachemgrpasswd
5212 LOC: Config.passwd_list
5214 Specify passwords for cachemgr operations.
5216 Usage: cachemgr_passwd password action action ...
5218 Some valid actions are (see cache manager menu for a full list):
5257 * Indicates actions which will not be performed without a
5258 valid password, others can be performed if not listed here.
5260 To disable an action, set the password to "disable".
5261 To allow performing an action without a password, set the
5264 Use the keyword "all" to set the same password for all actions.
5267 cachemgr_passwd secret shutdown
5268 cachemgr_passwd lesssssssecret info stats/objects
5269 cachemgr_passwd disable all
5276 LOC: Config.onoff.client_db
5278 If you want to disable collecting per-client statistics,
5279 turn off client_db here.
5282 NAME: refresh_all_ims
5286 LOC: Config.onoff.refresh_all_ims
5288 When you enable this option, squid will always check
5289 the origin server for an update when a client sends an
5290 If-Modified-Since request. Many browsers use IMS
5291 requests when the user requests a reload, and this
5292 ensures those clients receive the latest version.
5294 By default (off), squid may return a Not Modified response
5295 based on the age of the cached version.
5298 NAME: reload_into_ims
5299 IFDEF: HTTP_VIOLATIONS
5303 LOC: Config.onoff.reload_into_ims
5305 When you enable this option, client no-cache or ``reload''
5306 requests will be changed to If-Modified-Since requests.
5307 Doing this VIOLATES the HTTP standard. Enabling this
5308 feature could make you liable for problems which it
5311 see also refresh_pattern for a more selective approach.
5314 NAME: maximum_single_addr_tries
5316 LOC: Config.retry.maxtries
5319 This sets the maximum number of connection attempts for a
5320 host that only has one address (for multiple-address hosts,
5321 each address is tried once).
5323 The default value is one attempt, the (not recommended)
5324 maximum is 255 tries. A warning message will be generated
5325 if it is set to a value greater than ten.
5327 Note: This is in addition to the request re-forwarding which
5328 takes place if Squid fails to get a satisfying response.
5331 NAME: retry_on_error
5333 LOC: Config.retry.onerror
5336 If set to on Squid will automatically retry requests when
5337 receiving an error response. This is mainly useful if you
5338 are in a complex cache hierarchy to work around access
5342 NAME: as_whois_server
5344 LOC: Config.as_whois_server
5345 DEFAULT: whois.ra.net
5346 DEFAULT_IF_NONE: whois.ra.net
5348 WHOIS server to query for AS numbers. NOTE: AS numbers are
5349 queried only when Squid starts up, not for every request.
5354 LOC: Config.onoff.offline
5357 Enable this option and Squid will never try to validate cached
5361 NAME: uri_whitespace
5362 TYPE: uri_whitespace
5363 LOC: Config.uri_whitespace
5366 What to do with requests that have whitespace characters in the
5369 strip: The whitespace characters are stripped out of the URL.
5370 This is the behavior recommended by RFC2396.
5371 deny: The request is denied. The user receives an "Invalid
5373 allow: The request is allowed and the URI is not changed. The
5374 whitespace characters remain in the URI. Note the
5375 whitespace is passed to redirector processes if they
5377 encode: The request is allowed and the whitespace characters are
5378 encoded according to RFC1738. This could be considered
5379 a violation of the HTTP/1.1
5380 RFC because proxies are not allowed to rewrite URI's.
5381 chop: The request is allowed and the URI is chopped at the
5382 first whitespace. This might also be considered a
5388 LOC: Config.coredump_dir
5390 DEFAULT_IF_NONE: none
5392 By default Squid leaves core files in the directory from where
5393 it was started. If you set 'coredump_dir' to a directory
5394 that exists, Squid will chdir() to that directory at startup
5395 and coredump files will be left there.
5398 # Leave coredumps in the first cache dir
5399 coredump_dir @DEFAULT_SWAP_DIR@
5405 LOC: Config.chroot_dir
5408 Use this to have Squid do a chroot() while initializing. This
5409 also causes Squid to fully drop root privileges after
5410 initializing. This means, for example, if you use a HTTP
5411 port less than 1024 and try to reconfigure, you will may get an
5412 error saying that Squid can not open the port.
5415 NAME: balance_on_multiple_ip
5417 LOC: Config.onoff.balance_on_multiple_ip
5420 Modern IP resolvers in squid sort lookup results by preferred access.
5421 By default squid will use these IP in order and only rotates to
5422 the next listed when the most preffered fails.
5424 Some load balancing servers based on round robin DNS have been
5425 found not to preserve user session state across requests
5426 to different IP addresses.
5428 Enabling this directive Squid rotates IP's per request.
5431 NAME: pipeline_prefetch
5433 LOC: Config.onoff.pipeline_prefetch
5436 To boost the performance of pipelined requests to closer
5437 match that of a non-proxied environment Squid can try to fetch
5438 up to two requests in parallel from a pipeline.
5440 Defaults to off for bandwidth management and access logging
5444 NAME: high_response_time_warning
5447 LOC: Config.warnings.high_rptm
5450 If the one-minute median response time exceeds this value,
5451 Squid prints a WARNING with debug level 0 to get the
5452 administrators attention. The value is in milliseconds.
5455 NAME: high_page_fault_warning
5457 LOC: Config.warnings.high_pf
5460 If the one-minute average page fault rate exceeds this
5461 value, Squid prints a WARNING with debug level 0 to get
5462 the administrators attention. The value is in page faults
5466 NAME: high_memory_warning
5468 LOC: Config.warnings.high_memory
5471 If the memory usage (as determined by mallinfo) exceeds
5472 this amount, Squid prints a WARNING with debug level 0 to get
5473 the administrators attention.
5476 NAME: sleep_after_fork
5477 COMMENT: (microseconds)
5479 LOC: Config.sleep_after_fork
5482 When this is set to a non-zero value, the main Squid process
5483 sleeps the specified number of microseconds after a fork()
5484 system call. This sleep may help the situation where your
5485 system reports fork() failures due to lack of (virtual)
5486 memory. Note, however, if you have a lot of child
5487 processes, these sleep delays will add up and your
5488 Squid will not service requests for some amount of time
5489 until all the child processes have been started.
5490 On Windows value less then 1000 (1 milliseconds) are