3 # $Id: cf.data.pre,v 1.493 2008/01/14 13:19:48 hno Exp $
5 # SQUID Web Proxy Cache http://www.squid-cache.org/
6 # ----------------------------------------------------------
8 # Squid is the result of efforts by numerous individuals from
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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 name= Specifies a internal name for the port. Defaults to
929 the port specification (port or addr:port)
931 If you run Squid on a dual-homed machine with an internal
932 and an external interface we recommend you to specify the
933 internal address:port in http_port. This way Squid will only be
934 visible on the internal address.
937 # Squid normally listens to port 3128
938 http_port @DEFAULT_HTTP_PORT@
944 TYPE: https_port_list
946 LOC: Config.Sockaddr.https
948 Usage: [ip:]port cert=certificate.pem [key=key.pem] [options...]
950 The socket address where Squid will listen for HTTPS client
953 This is really only useful for situations where you are running
954 squid in accelerator mode and you want to do the SSL work at the
957 You may specify multiple socket addresses on multiple lines,
958 each with their own SSL certificate and/or options.
962 accel Accelerator mode. Also needs at least one of
963 defaultsite or vhost.
965 defaultsite= The name of the https site presented on
966 this port. Implies accel.
968 vhost Accelerator mode using Host header for virtual
969 domain support. Requires a wildcard certificate
970 or other certificate valid for more than one domain.
973 protocol= Protocol to reconstruct accelerated requests with.
976 cert= Path to SSL certificate (PEM format).
978 key= Path to SSL private key file (PEM format)
979 if not specified, the certificate file is
980 assumed to be a combined certificate and
983 version= The version of SSL/TLS supported
984 1 automatic (default)
989 cipher= Colon separated list of supported ciphers.
991 options= Various SSL engine options. The most important
993 NO_SSLv2 Disallow the use of SSLv2
994 NO_SSLv3 Disallow the use of SSLv3
995 NO_TLSv1 Disallow the use of TLSv1
996 SINGLE_DH_USE Always create a new key when using
997 temporary/ephemeral DH key exchanges
998 See src/ssl_support.c or OpenSSL SSL_CTX_set_options
999 documentation for a complete list of options.
1001 clientca= File containing the list of CAs to use when
1002 requesting a client certificate.
1004 cafile= File containing additional CA certificates to
1005 use when verifying client certificates. If unset
1006 clientca will be used.
1008 capath= Directory containing additional CA certificates
1009 and CRL lists to use when verifying client certificates.
1011 crlfile= File of additional CRL lists to use when verifying
1012 the client certificate, in addition to CRLs stored in
1013 the capath. Implies VERIFY_CRL flag below.
1015 dhparams= File containing DH parameters for temporary/ephemeral
1018 sslflags= Various flags modifying the use of SSL:
1020 Don't request client certificates
1021 immediately, but wait until acl processing
1022 requires a certificate (not yet implemented).
1024 Don't use the default CA lists built in
1027 Don't allow for session reuse. Each connection
1028 will result in a new SSL session.
1030 Verify CRL lists when accepting client
1033 Verify CRL lists for all certificates in the
1034 client certificate chain.
1036 sslcontext= SSL session ID context identifier.
1038 vport Accelerator with IP based virtual host support.
1040 vport=NN As above, but uses specified port number rather
1041 than the https_port number. Implies accel.
1043 name= Specifies a internal name for the port. Defaults to
1044 the port specification (port or addr:port)
1048 NAME: tcp_outgoing_tos tcp_outgoing_ds tcp_outgoing_dscp
1051 LOC: Config.accessList.outgoing_tos
1053 Allows you to select a TOS/Diffserv value to mark outgoing
1054 connections with, based on the username or source address
1057 tcp_outgoing_tos ds-field [!]aclname ...
1059 Example where normal_service_net uses the TOS value 0x00
1060 and normal_service_net uses 0x20
1062 acl normal_service_net src 10.0.0.0/255.255.255.0
1063 acl good_service_net src 10.0.1.0/255.255.255.0
1064 tcp_outgoing_tos 0x00 normal_service_net
1065 tcp_outgoing_tos 0x20 good_service_net
1067 TOS/DSCP values really only have local significance - so you should
1068 know what you're specifying. For more information, see RFC2474 and
1071 The TOS/DSCP byte must be exactly that - a octet value 0 - 255, or
1072 "default" to use whatever default your host has. Note that in
1073 practice often only values 0 - 63 is usable as the two highest bits
1074 have been redefined for use by ECN (RFC3168).
1076 Processing proceeds in the order specified, and stops at first fully
1079 Note: The use of this directive using client dependent ACLs is
1080 incompatible with the use of server side persistent connections. To
1081 ensure correct results it is best to set server_persisten_connections
1082 to off when using this directive in such configurations.
1085 NAME: clientside_tos
1088 LOC: Config.accessList.clientside_tos
1090 Allows you to select a TOS/Diffserv value to mark client-side
1091 connections with, based on the username or source address
1095 NAME: tcp_outgoing_address
1098 LOC: Config.accessList.outgoing_address
1100 Allows you to map requests to different outgoing IP addresses
1101 based on the username or source address of the user making
1104 tcp_outgoing_address ipaddr [[!]aclname] ...
1106 Example where requests from 10.0.0.0/24 will be forwarded
1107 with source address 10.1.0.1, 10.0.2.0/24 forwarded with
1108 source address 10.1.0.2 and the rest will be forwarded with
1109 source address 10.1.0.3.
1111 acl normal_service_net src 10.0.0.0/255.255.255.0
1112 acl good_service_net src 10.0.1.0/255.255.255.0
1113 tcp_outgoing_address 10.0.0.1 normal_service_net
1114 tcp_outgoing_address 10.0.0.2 good_service_net
1115 tcp_outgoing_address 10.0.0.3
1117 Processing proceeds in the order specified, and stops at first fully
1120 Note: The use of this directive using client dependent ACLs is
1121 incompatible with the use of server side persistent connections. To
1122 ensure correct results it is best to set server_persistent_connections
1123 to off when using this directive in such configurations.
1128 Squid is built with a capability of bridging the IPv4 and IPv6 internets.
1129 tcp_outgoing_address as exampled above breaks this bridging by forcing
1130 all outbound traffic through a certain IPv4 which may be on the wrong
1131 side of the IPv4/IPv6 boundary.
1133 To operate with tcp_outgoing_address and keep the bridging benefits
1134 an additional ACL needs to be used which ensures the IPv6-bound traffic
1135 is never forced or permitted out the IPv4 interface.
1137 acl to_ipv6 dst ipv6
1138 tcp_outgoing_address 2002::c001 good_service_net to_ipv6
1139 tcp_outgoing_address 10.0.0.2 good_service_net !to_ipv6
1141 tcp_outgoing_address 2002::beef normal_service_net to_ipv6
1142 tcp_outgoing_address 10.0.0.1 normal_service_net !to_ipv6
1144 tcp_outgoing_address 2002::1 to_ipv6
1145 tcp_outgoing_address 10.0.0.3 !to_ipv6
1150 -----------------------------------------------------------------------------
1153 NAME: ssl_unclean_shutdown
1157 LOC: Config.SSL.unclean_shutdown
1159 Some browsers (especially MSIE) bugs out on SSL shutdown
1166 LOC: Config.SSL.ssl_engine
1169 The OpenSSL engine to use. You will need to set this if you
1170 would like to use hardware SSL acceleration for example.
1173 NAME: sslproxy_client_certificate
1176 LOC: Config.ssl_client.cert
1179 Client SSL Certificate to use when proxying https:// URLs
1182 NAME: sslproxy_client_key
1185 LOC: Config.ssl_client.key
1188 Client SSL Key to use when proxying https:// URLs
1191 NAME: sslproxy_version
1194 LOC: Config.ssl_client.version
1197 SSL version level to use when proxying https:// URLs
1200 NAME: sslproxy_options
1203 LOC: Config.ssl_client.options
1206 SSL engine options to use when proxying https:// URLs
1209 NAME: sslproxy_cipher
1212 LOC: Config.ssl_client.cipher
1215 SSL cipher list to use when proxying https:// URLs
1218 NAME: sslproxy_cafile
1221 LOC: Config.ssl_client.cafile
1224 file containing CA certificates to use when verifying server
1225 certificates while proxying https:// URLs
1228 NAME: sslproxy_capath
1231 LOC: Config.ssl_client.capath
1234 directory containing CA certificates to use when verifying
1235 server certificates while proxying https:// URLs
1238 NAME: sslproxy_flags
1241 LOC: Config.ssl_client.flags
1244 Various flags modifying the use of SSL while proxying https:// URLs:
1245 DONT_VERIFY_PEER Accept certificates even if they fail to
1247 NO_DEFAULT_CA Don't use the default CA list built in
1251 NAME: sslpassword_program
1254 LOC: Config.Program.ssl_password
1257 Specify a program used for entering SSL key passphrases
1258 when using encrypted SSL certificate keys. If not specified
1259 keys must either be unencrypted, or Squid started with the -N
1260 option to allow it to query interactively for the passphrase.
1264 OPTIONS WHICH AFFECT THE NEIGHBOR SELECTION ALGORITHM
1265 -----------------------------------------------------------------------------
1273 To specify other caches in a hierarchy, use the format:
1275 cache_peer hostname type http-port icp-port [options]
1280 # hostname type port port options
1281 # -------------------- -------- ----- ----- -----------
1282 cache_peer parent.foo.net parent 3128 3130 proxy-only default
1283 cache_peer sib1.foo.net sibling 3128 3130 proxy-only
1284 cache_peer sib2.foo.net sibling 3128 3130 proxy-only
1286 type: either 'parent', 'sibling', or 'multicast'.
1288 proxy-port: The port number where the cache listens for proxy
1291 icp-port: Used for querying neighbor caches about
1292 objects. To have a non-ICP neighbor
1293 specify '7' for the ICP port and make sure the
1294 neighbor machine has the UDP echo port
1295 enabled in its /etc/inetd.conf file.
1296 NOTE: Also requires icp_port option enabled to send/receive
1297 requests via this method.
1307 weighted-round-robin
1314 login=user:password | PASS | *:password
1325 sslcert=/path/to/ssl/certificate
1326 sslkey=/path/to/ssl/key
1330 front-end-https[=on|auto]
1332 use 'proxy-only' to specify objects fetched
1333 from this cache should not be saved locally.
1335 use 'weight=n' to affect the selection of a peer
1336 during any weighted peer-selection mechanisms.
1337 The weight must be an integer; default is 1,
1338 larger weights are favored more.
1339 This option does not affect parent selection if a peering
1340 protocol is not in use.
1342 use 'basetime=n' to specify a base amount to
1343 be subtracted from round trip times of parents.
1344 It is subtracted before division by weight in calculating
1345 which parent to fectch from. If the rtt is less than the
1346 base time the rtt is set to a minimal value.
1348 use 'ttl=n' to specify a IP multicast TTL to use
1349 when sending an ICP queries to this address.
1350 Only useful when sending to a multicast group.
1351 Because we don't accept ICP replies from random
1352 hosts, you must configure other group members as
1353 peers with the 'multicast-responder' option below.
1355 use 'no-query' to NOT send ICP queries to this
1358 use 'background-ping' to only send ICP queries to this
1359 neighbor infrequently. This is used to keep the neighbor
1360 round trip time updated and is usually used in
1361 conjunction with weighted-round-robin.
1363 use 'default' if this is a parent cache which can
1364 be used as a "last-resort" if a peer cannot be located
1365 by any of the peer-selection mechanisms.
1366 If specified more than once, only the first is used.
1368 use 'round-robin' to define a set of parents which
1369 should be used in a round-robin fashion in the
1370 absence of any ICP queries.
1372 use 'weighted-round-robin' to define a set of parents
1373 which should be used in a round-robin fashion with the
1374 frequency of each parent being based on the round trip
1375 time. Closer parents are used more often.
1376 Usually used for background-ping parents.
1378 use 'carp' to define a set of parents which should
1379 be used as a CARP array. The requests will be
1380 distributed among the parents based on the CARP load
1381 balancing hash function based on their weight.
1383 'multicast-responder' indicates the named peer
1384 is a member of a multicast group. ICP queries will
1385 not be sent directly to the peer, but ICP replies
1386 will be accepted from it.
1388 'closest-only' indicates that, for ICP_OP_MISS
1389 replies, we'll only forward CLOSEST_PARENT_MISSes
1390 and never FIRST_PARENT_MISSes.
1392 use 'no-digest' to NOT request cache digests from
1395 'no-netdb-exchange' disables requesting ICMP
1396 RTT database (NetDB) from the neighbor.
1398 use 'no-delay' to prevent access to this neighbor
1399 from influencing the delay pools.
1401 use 'login=user:password' if this is a personal/workgroup
1402 proxy and your parent requires proxy authentication.
1403 Note: The string can include URL escapes (i.e. %20 for
1404 spaces). This also means % must be written as %%.
1406 use 'login=PASS' if users must authenticate against
1407 the upstream proxy or in the case of a reverse proxy
1408 configuration, the origin web server. This will pass
1409 the users credentials as they are to the peer.
1410 This only works for the Basic HTTP authentication scheme.
1411 Note: To combine this with proxy_auth both proxies must
1412 share the same user database as HTTP only allows for
1413 a single login (one for proxy, one for origin server).
1414 Also be warned this will expose your users proxy
1415 password to the peer. USE WITH CAUTION
1417 use 'login=*:password' to pass the username to the
1418 upstream cache, but with a fixed password. This is meant
1419 to be used when the peer is in another administrative
1420 domain, but it is still needed to identify each user.
1421 The star can optionally be followed by some extra
1422 information which is added to the username. This can
1423 be used to identify this proxy to the peer, similar to
1424 the login=username:password option above.
1426 use 'connect-timeout=nn' to specify a peer
1427 specific connect timeout (also see the
1428 peer_connect_timeout directive)
1430 use 'digest-url=url' to tell Squid to fetch the cache
1431 digest (if digests are enabled) for this host from
1432 the specified URL rather than the Squid default
1435 use 'allow-miss' to disable Squid's use of only-if-cached
1436 when forwarding requests to siblings. This is primarily
1437 useful when icp_hit_stale is used by the sibling. To
1438 extensive use of this option may result in forwarding
1439 loops, and you should avoid having two-way peerings
1440 with this option. (for example to deny peer usage on
1441 requests from peer by denying cache_peer_access if the
1444 use 'max-conn=n' to limit the amount of connections Squid
1445 may open to this peer.
1447 use 'htcp' to send HTCP, instead of ICP, queries
1448 to the neighbor. You probably also want to
1449 set the "icp port" to 4827 instead of 3130.
1450 You MUST also set htcp_access expicitly. The default of
1451 deny all will prevent peer traffic.
1453 use 'htcp-oldsquid' to send HTCP to old Squid versions
1454 You MUST also set htcp_access expicitly. The default of
1455 deny all will prevent peer traffic.
1457 'originserver' causes this parent peer to be contacted as
1458 a origin server. Meant to be used in accelerator setups.
1460 use 'name=xxx' if you have multiple peers on the same
1461 host but different ports. This name can be used to
1462 differentiate the peers in cache_peer_access and similar
1465 use 'forceddomain=name' to forcibly set the Host header
1466 of requests forwarded to this peer. Useful in accelerator
1467 setups where the server (peer) expects a certain domain
1468 name and using redirectors to feed this domain name
1471 use 'ssl' to indicate connections to this peer should
1472 be SSL/TLS encrypted.
1474 use 'sslcert=/path/to/ssl/certificate' to specify a client
1475 SSL certificate to use when connecting to this peer.
1477 use 'sslkey=/path/to/ssl/key' to specify the private SSL
1478 key corresponding to sslcert above. If 'sslkey' is not
1479 specified 'sslcert' is assumed to reference a
1480 combined file containing both the certificate and the key.
1482 use sslversion=1|2|3|4 to specify the SSL version to use
1483 when connecting to this peer
1484 1 = automatic (default)
1489 use sslcipher=... to specify the list of valid SSL ciphers
1490 to use when connecting to this peer.
1492 use ssloptions=... to specify various SSL engine options:
1493 NO_SSLv2 Disallow the use of SSLv2
1494 NO_SSLv3 Disallow the use of SSLv3
1495 NO_TLSv1 Disallow the use of TLSv1
1496 See src/ssl_support.c or the OpenSSL documentation for
1497 a more complete list.
1499 use sslcafile=... to specify a file containing
1500 additional CA certificates to use when verifying the
1503 use sslcapath=... to specify a directory containing
1504 additional CA certificates to use when verifying the
1507 use sslcrlfile=... to specify a certificate revocation
1508 list file to use when verifying the peer certificate.
1510 use sslflags=... to specify various flags modifying the
1513 Accept certificates even if they fail to
1516 Don't use the default CA list built in
1519 Don't verify the peer certificate
1520 matches the server name
1522 use ssldomain= to specify the peer name as advertised
1523 in it's certificate. Used for verifying the correctness
1524 of the received peer certificate. If not specified the
1525 peer hostname will be used.
1527 use front-end-https to enable the "Front-End-Https: On"
1528 header needed when using Squid as a SSL frontend in front
1529 of Microsoft OWA. See MS KB document Q307347 for details
1530 on this header. If set to auto the header will
1531 only be added if the request is forwarded as a https://
1535 NAME: cache_peer_domain cache_host_domain
1540 Use to limit the domains for which a neighbor cache will be
1543 cache_peer_domain cache-host domain [domain ...]
1544 cache_peer_domain cache-host !domain
1546 For example, specifying
1548 cache_peer_domain parent.foo.net .edu
1550 has the effect such that UDP query packets are sent to
1551 'bigserver' only when the requested object exists on a
1552 server in the .edu domain. Prefixing the domainname
1553 with '!' means the cache will be queried for objects
1556 NOTE: * Any number of domains may be given for a cache-host,
1557 either on the same or separate lines.
1558 * When multiple domains are given for a particular
1559 cache-host, the first matched domain is applied.
1560 * Cache hosts with no domain restrictions are queried
1562 * There are no defaults.
1563 * There is also a 'cache_peer_access' tag in the ACL
1567 NAME: cache_peer_access
1572 Similar to 'cache_peer_domain' but provides more flexibility by
1575 cache_peer_access cache-host allow|deny [!]aclname ...
1577 The syntax is identical to 'http_access' and the other lists of
1578 ACL elements. See the comments for 'http_access' below, or
1579 the Squid FAQ (http://www.squid-cache.org/FAQ/FAQ-10.html).
1582 NAME: neighbor_type_domain
1583 TYPE: hostdomaintype
1587 usage: neighbor_type_domain neighbor parent|sibling domain domain ...
1589 Modifying the neighbor type for specific domains is now
1590 possible. You can treat some domains differently than the the
1591 default neighbor type specified on the 'cache_peer' line.
1592 Normally it should only be necessary to list domains which
1593 should be treated differently because the default neighbor type
1594 applies for hostnames which do not match domains listed here.
1597 cache_peer cache.foo.org parent 3128 3130
1598 neighbor_type_domain cache.foo.org sibling .com .net
1599 neighbor_type_domain cache.foo.org sibling .au .de
1602 NAME: dead_peer_timeout
1606 LOC: Config.Timeout.deadPeer
1608 This controls how long Squid waits to declare a peer cache
1609 as "dead." If there are no ICP replies received in this
1610 amount of time, Squid will declare the peer dead and not
1611 expect to receive any further ICP replies. However, it
1612 continues to send ICP queries, and will mark the peer as
1613 alive upon receipt of the first subsequent ICP reply.
1615 This timeout also affects when Squid expects to receive ICP
1616 replies from peers. If more than 'dead_peer' seconds have
1617 passed since the last ICP reply was received, Squid will not
1618 expect to receive an ICP reply on the next query. Thus, if
1619 your time between requests is greater than this timeout, you
1620 will see a lot of requests sent DIRECT to origin servers
1621 instead of to your parents.
1624 NAME: hierarchy_stoplist
1627 LOC: Config.hierarchy_stoplist
1629 A list of words which, if found in a URL, cause the object to
1630 be handled directly by this cache. In other words, use this
1631 to not query neighbor caches for certain objects. You may
1632 list this option multiple times.
1633 Note: never_direct overrides this option.
1635 #We recommend you to use at least the following line.
1636 hierarchy_stoplist cgi-bin ?
1641 MEMORY CACHE OPTIONS
1642 -----------------------------------------------------------------------------
1649 LOC: Config.memMaxSize
1651 NOTE: THIS PARAMETER DOES NOT SPECIFY THE MAXIMUM PROCESS SIZE.
1652 IT ONLY PLACES A LIMIT ON HOW MUCH ADDITIONAL MEMORY SQUID WILL
1653 USE AS A MEMORY CACHE OF OBJECTS. SQUID USES MEMORY FOR OTHER
1654 THINGS AS WELL. SEE THE SQUID FAQ SECTION 8 FOR DETAILS.
1656 'cache_mem' specifies the ideal amount of memory to be used
1658 * In-Transit objects
1660 * Negative-Cached objects
1662 Data for these objects are stored in 4 KB blocks. This
1663 parameter specifies the ideal upper limit on the total size of
1664 4 KB blocks allocated. In-Transit objects take the highest
1667 In-transit objects have priority over the others. When
1668 additional space is needed for incoming data, negative-cached
1669 and hot objects will be released. In other words, the
1670 negative-cached and hot objects will fill up any unused space
1671 not needed for in-transit objects.
1673 If circumstances require, this limit will be exceeded.
1674 Specifically, if your incoming request rate requires more than
1675 'cache_mem' of memory to hold in-transit objects, Squid will
1676 exceed this limit to satisfy the new requests. When the load
1677 decreases, blocks will be freed until the high-water mark is
1678 reached. Thereafter, blocks will be used to store hot
1682 NAME: maximum_object_size_in_memory
1686 LOC: Config.Store.maxInMemObjSize
1688 Objects greater than this size will not be attempted to kept in
1689 the memory cache. This should be set high enough to keep objects
1690 accessed frequently in memory to improve performance whilst low
1691 enough to keep larger objects from hoarding cache_mem.
1694 NAME: memory_replacement_policy
1696 LOC: Config.memPolicy
1699 The memory replacement policy parameter determines which
1700 objects are purged from memory when memory space is needed.
1702 See cache_replacement_policy for details.
1707 -----------------------------------------------------------------------------
1710 NAME: cache_replacement_policy
1712 LOC: Config.replPolicy
1715 The cache replacement policy parameter determines which
1716 objects are evicted (replaced) when disk space is needed.
1718 lru : Squid's original list based LRU policy
1719 heap GDSF : Greedy-Dual Size Frequency
1720 heap LFUDA: Least Frequently Used with Dynamic Aging
1721 heap LRU : LRU policy implemented using a heap
1723 Applies to any cache_dir lines listed below this.
1725 The LRU policies keeps recently referenced objects.
1727 The heap GDSF policy optimizes object hit rate by keeping smaller
1728 popular objects in cache so it has a better chance of getting a
1729 hit. It achieves a lower byte hit rate than LFUDA though since
1730 it evicts larger (possibly popular) objects.
1732 The heap LFUDA policy keeps popular objects in cache regardless of
1733 their size and thus optimizes byte hit rate at the expense of
1734 hit rate since one large, popular object will prevent many
1735 smaller, slightly less popular objects from being cached.
1737 Both policies utilize a dynamic aging mechanism that prevents
1738 cache pollution that can otherwise occur with frequency-based
1739 replacement policies.
1741 NOTE: if using the LFUDA replacement policy you should increase
1742 the value of maximum_object_size above its default of 4096 KB to
1743 to maximize the potential byte hit rate improvement of LFUDA.
1745 For more information about the GDSF and LFUDA cache replacement
1746 policies see http://www.hpl.hp.com/techreports/1999/HPL-1999-69.html
1747 and http://fog.hpl.external.hp.com/techreports/98/HPL-98-173.html.
1753 LOC: Config.cacheSwap
1757 cache_dir Type Directory-Name Fs-specific-data [options]
1759 You can specify multiple cache_dir lines to spread the
1760 cache among different disk partitions.
1762 Type specifies the kind of storage system to use. Only "ufs"
1763 is built by default. To enable any of the other storage systems
1764 see the --enable-storeio configure option.
1766 'Directory' is a top-level directory where cache swap
1767 files will be stored. If you want to use an entire disk
1768 for caching, this can be the mount-point directory.
1769 The directory must exist and be writable by the Squid
1770 process. Squid will NOT create this directory for you.
1774 "ufs" is the old well-known Squid storage format that has always
1777 cache_dir ufs Directory-Name Mbytes L1 L2 [options]
1779 'Mbytes' is the amount of disk space (MB) to use under this
1780 directory. The default is 100 MB. Change this to suit your
1781 configuration. Do NOT put the size of your disk drive here.
1782 Instead, if you want Squid to use the entire disk drive,
1783 subtract 20% and use that value.
1785 'Level-1' is the number of first-level subdirectories which
1786 will be created under the 'Directory'. The default is 16.
1788 'Level-2' is the number of second-level subdirectories which
1789 will be created under each first-level directory. The default
1792 The aufs store type:
1794 "aufs" uses the same storage format as "ufs", utilizing
1795 POSIX-threads to avoid blocking the main Squid process on
1796 disk-I/O. This was formerly known in Squid as async-io.
1798 cache_dir aufs Directory-Name Mbytes L1 L2 [options]
1800 see argument descriptions under ufs above
1802 The diskd store type:
1804 "diskd" uses the same storage format as "ufs", utilizing a
1805 separate process to avoid blocking the main Squid process on
1808 cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n]
1810 see argument descriptions under ufs above
1812 Q1 specifies the number of unacknowledged I/O requests when Squid
1813 stops opening new files. If this many messages are in the queues,
1814 Squid won't open new files. Default is 64
1816 Q2 specifies the number of unacknowledged messages when Squid
1817 starts blocking. If this many messages are in the queues,
1818 Squid blocks until it receives some replies. Default is 72
1820 When Q1 < Q2 (the default), the cache directory is optimized
1821 for lower response time at the expense of a decrease in hit
1822 ratio. If Q1 > Q2, the cache directory is optimized for
1823 higher hit ratio at the expense of an increase in response
1826 The coss store type:
1828 block-size=n defines the "block size" for COSS cache_dir's.
1829 Squid uses file numbers as block numbers. Since file numbers
1830 are limited to 24 bits, the block size determines the maximum
1831 size of the COSS partition. The default is 512 bytes, which
1832 leads to a maximum cache_dir size of 512<<24, or 8 GB. Note
1833 you should not change the coss block size after Squid
1834 has written some objects to the cache_dir.
1836 The coss file store has changed from 2.5. Now it uses a file
1837 called 'stripe' in the directory names in the config - and
1838 this will be created by squid -z.
1842 no-store, no new objects should be stored to this cache_dir
1844 max-size=n, refers to the max object size this storedir supports.
1845 It is used to initially choose the storedir to dump the object.
1846 Note: To make optimal use of the max-size limits you should order
1847 the cache_dir lines with the smallest max-size value first and the
1848 ones with no max-size specification last.
1850 Note for coss, max-size must be less than COSS_MEMBUF_SZ,
1851 which can be changed with the --with-coss-membuf-size=N configure
1854 DEFAULT_IF_NONE: ufs @DEFAULT_SWAP_DIR@ 100 16 256
1858 NAME: store_dir_select_algorithm
1860 LOC: Config.store_dir_select_algorithm
1863 Set this to 'round-robin' as an alternative.
1866 NAME: max_open_disk_fds
1868 LOC: Config.max_open_disk_fds
1871 To avoid having disk as the I/O bottleneck Squid can optionally
1872 bypass the on-disk cache if more than this amount of disk file
1873 descriptors are open.
1875 A value of 0 indicates no limit.
1878 NAME: minimum_object_size
1882 LOC: Config.Store.minObjectSize
1884 Objects smaller than this size will NOT be saved on disk. The
1885 value is specified in kilobytes, and the default is 0 KB, which
1886 means there is no minimum.
1889 NAME: maximum_object_size
1893 LOC: Config.Store.maxObjectSize
1895 Objects larger than this size will NOT be saved on disk. The
1896 value is specified in kilobytes, and the default is 4MB. If
1897 you wish to get a high BYTES hit ratio, you should probably
1898 increase this (one 32 MB object hit counts for 3200 10KB
1899 hits). If you wish to increase speed more than your want to
1900 save bandwidth you should leave this low.
1902 NOTE: if using the LFUDA replacement policy you should increase
1903 this value to maximize the byte hit rate improvement of LFUDA!
1904 See replacement_policy below for a discussion of this policy.
1907 NAME: cache_swap_low
1908 COMMENT: (percent, 0-100)
1911 LOC: Config.Swap.lowWaterMark
1914 NAME: cache_swap_high
1915 COMMENT: (percent, 0-100)
1918 LOC: Config.Swap.highWaterMark
1921 The low- and high-water marks for cache object replacement.
1922 Replacement begins when the swap (disk) usage is above the
1923 low-water mark and attempts to maintain utilization near the
1924 low-water mark. As swap utilization gets close to high-water
1925 mark object eviction becomes more aggressive. If utilization is
1926 close to the low-water mark less replacement is done each time.
1928 Defaults are 90% and 95%. If you have a large cache, 5% could be
1929 hundreds of MB. If this is the case you may wish to set these
1930 numbers closer together.
1935 -----------------------------------------------------------------------------
1940 LOC: Config.Log.logformats
1945 logformat <name> <format specification>
1947 Defines an access log format.
1949 The <format specification> is a string with embedded % format codes
1951 % format codes all follow the same basic structure where all but
1952 the formatcode is optional. Output strings are automatically escaped
1953 as required according to their context and the output format
1954 modifiers are usually not needed, but can be specified if an explicit
1955 output format is desired.
1957 % ["|[|'|#] [-] [[0]width] [{argument}] formatcode
1959 " output in quoted string format
1960 [ output in squid text log format as used by log_mime_hdrs
1961 # output in URL quoted format
1965 width field width. If starting with 0 the
1966 output is zero padded
1967 {arg} argument such as header name etc
1971 >a Client source IP address
1973 >p Client source port
1974 <A Server IP address or peer name
1975 la Local IP address (http_port)
1976 lp Local port number (http_port)
1977 ts Seconds since epoch
1978 tu subsecond time (milliseconds)
1979 tl Local time. Optional strftime format argument
1980 default %d/%b/%Y:%H:%M:%S %z
1981 tg GMT time. Optional strftime format argument
1982 default %d/%b/%Y:%H:%M:%S %z
1983 tr Response time (milliseconds)
1984 >h Request header. Optional header name argument
1985 on the format header[:[separator]element]
1986 <h Reply header. Optional header name argument
1989 ul User name from authentication
1990 ui User name from ident
1991 us User name from SSL
1992 ue User name from external acl helper
1994 Ss Squid request status (TCP_MISS etc)
1995 Sh Squid hierarchy status (DEFAULT_PARENT etc)
1996 mt MIME content type
1997 rm Request method (GET/POST etc)
1999 rp Request URL-Path excluding hostname
2000 rv Request protocol version
2001 et Tag returned by external acl
2002 ea Log string returned by external acl
2003 <st Reply size including HTTP headers
2004 <sH Reply high offset sent
2005 <sS Upstream object size
2006 % a literal % character
2008 logformat squid %ts.%03tu %6tr %>a %Ss/%03Hs %<st %rm %ru %un %Sh/%<A %mt
2009 logformat squidmime %ts.%03tu %6tr %>a %Ss/%03Hs %<st %rm %ru %un %Sh/%<A %mt [%>h] [%<h]
2010 logformat common %>a %ui %un [%tl] "%rm %ru HTTP/%rv" %Hs %<st %Ss:%Sh
2011 logformat combined %>a %ui %un [%tl] "%rm %ru HTTP/%rv" %Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
2014 NAME: access_log cache_access_log
2016 LOC: Config.Log.accesslogs
2019 These files log client request activities. Has a line every HTTP or
2020 ICP request. The format is:
2021 access_log <filepath> [<logformat name> [acl acl ...]]
2022 access_log none [acl acl ...]]
2024 Will log to the specified file using the specified format (which
2025 must be defined in a logformat directive) those entries which match
2026 ALL the acl's specified (which must be defined in acl clauses).
2027 If no acl is specified, all requests will be logged to this file.
2029 To disable logging of a request use the filepath "none", in which case
2030 a logformat name should not be specified.
2032 To log the request via syslog specify a filepath of "syslog":
2034 access_log syslog[:facility.priority] [format [acl1 [acl2 ....]]]
2035 where facility could be any of:
2036 authpriv, daemon, local0 .. local7 or user.
2038 And priority could be any of:
2039 err, warning, notice, info, debug.
2041 access_log @DEFAULT_ACCESS_LOG@ squid
2047 LOC: Config.accessList.log
2049 COMMENT: allow|deny acl acl...
2051 This options allows you to control which requests gets logged
2052 to access.log (see access_log directive). Requests denied for
2053 logging will also not be accounted for in performance counters.
2058 DEFAULT: @DEFAULT_CACHE_LOG@
2061 Cache logging file. This is where general information about
2062 your cache's behavior goes. You can increase the amount of data
2063 logged to this file with the "debug_options" tag below.
2066 NAME: cache_store_log
2068 DEFAULT: @DEFAULT_STORE_LOG@
2069 LOC: Config.Log.store
2071 Logs the activities of the storage manager. Shows which
2072 objects are ejected from the cache, and which objects are
2073 saved and for how long. To disable, enter "none". There are
2074 not really utilities to analyze this data, so you can safely
2078 NAME: cache_swap_state cache_swap_log
2080 LOC: Config.Log.swap
2083 Location for the cache "swap.state" file. This index file holds
2084 the metadata of objects saved on disk. It is used to rebuild
2085 the cache during startup. Normally this file resides in each
2086 'cache_dir' directory, but you may specify an alternate
2087 pathname here. Note you must give a full filename, not just
2088 a directory. Since this is the index for the whole object
2089 list you CANNOT periodically rotate it!
2091 If %s can be used in the file name it will be replaced with a
2092 a representation of the cache_dir name where each / is replaced
2093 with '.'. This is needed to allow adding/removing cache_dir
2094 lines when cache_swap_log is being used.
2096 If have more than one 'cache_dir', and %s is not used in the name
2097 these swap logs will have names such as:
2103 The numbered extension (which is added automatically)
2104 corresponds to the order of the 'cache_dir' lines in this
2105 configuration file. If you change the order of the 'cache_dir'
2106 lines in this file, these index files will NOT correspond to
2107 the correct 'cache_dir' entry (unless you manually rename
2108 them). We recommend you do NOT use this option. It is
2109 better to keep these index files in each 'cache_dir' directory.
2112 NAME: logfile_rotate
2115 LOC: Config.Log.rotateNumber
2117 Specifies the number of logfile rotations to make when you
2118 type 'squid -k rotate'. The default is 10, which will rotate
2119 with extensions 0 through 9. Setting logfile_rotate to 0 will
2120 disable the file name rotation, but the logfiles are still closed
2121 and re-opened. This will enable you to rename the logfiles
2122 yourself just before sending the rotate signal.
2124 Note, the 'squid -k rotate' command normally sends a USR1
2125 signal to the running squid process. In certain situations
2126 (e.g. on Linux with Async I/O), USR1 is used for other
2127 purposes, so -k rotate uses another signal. It is best to get
2128 in the habit of using 'squid -k rotate' instead of 'kill -USR1
2132 NAME: emulate_httpd_log
2136 LOC: Config.onoff.common_log
2138 The Cache can emulate the log file format which many 'httpd'
2139 programs use. To disable/enable this emulation, set
2140 emulate_httpd_log to 'off' or 'on'. The default
2141 is to use the native log format since it includes useful
2142 information Squid-specific log analyzers use.
2145 NAME: log_ip_on_direct
2149 LOC: Config.onoff.log_ip_on_direct
2151 Log the destination IP address in the hierarchy log tag when going
2152 direct. Earlier Squid versions logged the hostname here. If you
2153 prefer the old way set this to off.
2158 DEFAULT: @DEFAULT_MIME_TABLE@
2159 LOC: Config.mimeTablePathname
2161 Pathname to Squid's MIME table. You shouldn't need to change
2162 this, but the default file contains examples and formatting
2163 information if you do.
2169 LOC: Config.onoff.log_mime_hdrs
2172 The Cache can record both the request and the response MIME
2173 headers for each HTTP transaction. The headers are encoded
2174 safely and will appear as two bracketed fields at the end of
2175 the access log (for either the native or httpd-emulated log
2176 formats). To enable this logging set log_mime_hdrs to 'on'.
2181 LOC: Config.Log.useragent
2183 IFDEF: USE_USERAGENT_LOG
2185 Squid will write the User-Agent field from HTTP requests
2186 to the filename specified here. By default useragent_log
2190 NAME: referer_log referrer_log
2192 LOC: Config.Log.referer
2194 IFDEF: USE_REFERER_LOG
2196 Squid will write the Referer field from HTTP requests to the
2197 filename specified here. By default referer_log is disabled.
2198 Note that "referer" is actually a misspelling of "referrer"
2199 however the misspelt version has been accepted into the HTTP RFCs
2205 DEFAULT: @DEFAULT_PID_FILE@
2206 LOC: Config.pidFilename
2208 A filename to write the process-id to. To disable, enter "none".
2214 LOC: Config.debugOptions
2216 Logging options are set as section,level where each source file
2217 is assigned a unique section. Lower levels result in less
2218 output, Full debugging (level 9) can result in a very large
2219 log file, so be careful. The magic word "ALL" sets debugging
2220 levels for all sections. We recommend normally running with
2228 LOC: Config.onoff.log_fqdn
2230 Turn this on if you wish to log fully qualified domain names
2231 in the access.log. To do this Squid does a DNS lookup of all
2232 IP's connecting to it. This can (in some situations) increase
2233 latency, which makes your cache seem slower for interactive
2237 NAME: client_netmask
2239 LOC: Config.Addrs.client_netmask
2240 DEFAULT: 255.255.255.255
2242 A netmask for client addresses in logfiles and cachemgr output.
2243 Change this to protect the privacy of your cache clients.
2244 A netmask of 255.255.255.0 will log all IP's in that range with
2245 the last digit set to '0'.
2252 LOC: Config.Log.forward
2254 Logs the server-side requests.
2256 This is currently work in progress.
2259 NAME: strip_query_terms
2261 LOC: Config.onoff.strip_query_terms
2264 By default, Squid strips query terms from requested URLs before
2265 logging. This protects your user's privacy.
2272 LOC: Config.onoff.buffered_logs
2274 cache.log log file is written with stdio functions, and as such
2275 it can be buffered or unbuffered. By default it will be unbuffered.
2276 Buffering it can speed up the writing slightly (though you are
2277 unlikely to need to worry unless you run with tons of debugging
2278 enabled in which case performance will suffer badly anyway..).
2281 NAME: netdb_filename
2283 DEFAULT: @DEFAULT_NETDB_FILE@
2284 LOC: Config.netdbFilename
2287 A filename where Squid stores it's netdb state between restarts.
2288 To disable, enter "none".
2292 OPTIONS FOR FTP GATEWAYING
2293 -----------------------------------------------------------------------------
2299 LOC: Config.Ftp.anon_user
2301 If you want the anonymous login password to be more informative
2302 (and enable the use of picky ftp servers), set this to something
2303 reasonable for your domain, like wwwuser@somewhere.net
2305 The reason why this is domainless by default is the
2306 request can be made on the behalf of a user in any domain,
2307 depending on how the cache is used.
2308 Some ftp server also validate the email address is valid
2309 (for example perl.com).
2312 NAME: ftp_list_width
2315 LOC: Config.Ftp.list_width
2317 Sets the width of ftp listings. This should be set to fit in
2318 the width of a standard browser. Setting this too small
2319 can cut off long filenames when browsing ftp sites.
2325 LOC: Config.Ftp.passive
2327 If your firewall does not allow Squid to use passive
2328 connections, turn off this option.
2331 NAME: ftp_sanitycheck
2334 LOC: Config.Ftp.sanitycheck
2336 For security and data integrity reasons Squid by default performs
2337 sanity checks of the addresses of FTP data connections ensure the
2338 data connection is to the requested server. If you need to allow
2339 FTP connections to servers using another IP address for the data
2340 connection turn this off.
2343 NAME: ftp_telnet_protocol
2346 LOC: Config.Ftp.telnet
2348 The FTP protocol is officially defined to use the telnet protocol
2349 as transport channel for the control connection. However, many
2350 implementations are broken and does not respect this aspect of
2353 If you have trouble accessing files with ASCII code 255 in the
2354 path or similar problems involving this ASCII code you can
2355 try setting this directive to off. If that helps, report to the
2356 operator of the FTP server in question that their FTP server
2357 is broken and does not follow the FTP standard.
2361 OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
2362 -----------------------------------------------------------------------------
2367 DEFAULT: @DEFAULT_DISKD@
2368 LOC: Config.Program.diskd
2370 Specify the location of the diskd executable.
2371 Note this is only useful if you have compiled in
2372 diskd as one of the store io modules.
2375 NAME: unlinkd_program
2378 DEFAULT: @DEFAULT_UNLINKD@
2379 LOC: Config.Program.unlinkd
2381 Specify the location of the executable for file deletion process.
2384 NAME: pinger_program
2386 DEFAULT: @DEFAULT_PINGER@
2387 LOC: Config.pinger.program
2390 Specify the location of the executable for the pinger process.
2396 LOC: Config.pinger.enable
2399 Control whether the pinger is active at run-time.
2400 Enables turning ICMP pinger on and off with a simple squid -k reconfigure.
2405 OPTIONS FOR URL REWRITING
2406 -----------------------------------------------------------------------------
2409 NAME: url_rewrite_program redirect_program
2411 LOC: Config.Program.redirect
2414 Specify the location of the executable for the URL rewriter.
2415 Since they can perform almost any function there isn't one included.
2417 For each requested URL rewriter will receive on line with the format
2419 URL <SP> client_ip "/" fqdn <SP> user <SP> method [<SP> kvpairs]<NL>
2421 In the future, the rewriter interface will be extended with
2422 key=value pairs ("kvpairs" shown above). Rewriter programs
2423 should be prepared to receive and possibly ignore additional
2424 whitespace-separated tokens on each input line.
2426 And the rewriter may return a rewritten URL. The other components of
2427 the request line does not need to be returned (ignored if they are).
2429 The rewriter can also indicate that a client-side redirect should
2430 be performed to the new URL. This is done by prefixing the returned
2431 URL with "301:" (moved permanently) or 302: (moved temporarily).
2433 By default, a URL rewriter is not used.
2436 NAME: url_rewrite_children redirect_children
2439 LOC: Config.redirectChildren
2441 The number of redirector processes to spawn. If you start
2442 too few Squid will have to wait for them to process a backlog of
2443 URLs, slowing it down. If you start too many they will use RAM
2444 and other system resources.
2447 NAME: url_rewrite_concurrency redirect_concurrency
2450 LOC: Config.redirectConcurrency
2452 The number of requests each redirector helper can handle in
2453 parallel. Defaults to 0 which indicates the redirector
2454 is a old-style single threaded redirector.
2457 NAME: url_rewrite_host_header redirect_rewrites_host_header
2460 LOC: Config.onoff.redir_rewrites_host
2462 By default Squid rewrites any Host: header in redirected
2463 requests. If you are running an accelerator this may
2464 not be a wanted effect of a redirector.
2466 WARNING: Entries are cached on the result of the URL rewriting
2467 process, so be careful if you have domain-virtual hosts.
2470 NAME: url_rewrite_access redirector_access
2473 LOC: Config.accessList.redirector
2475 If defined, this access list specifies which requests are
2476 sent to the redirector processes. By default all requests
2480 NAME: url_rewrite_bypass redirector_bypass
2482 LOC: Config.onoff.redirector_bypass
2485 When this is 'on', a request will not go through the
2486 redirector if all redirectors are busy. If this is 'off'
2487 and the redirector queue grows too large, Squid will exit
2488 with a FATAL error and ask you to increase the number of
2489 redirectors. You should only enable this if the redirectors
2490 are not critical to your caching system. If you use
2491 redirectors for access control, and you enable this option,
2492 users may have access to pages they should not
2493 be allowed to request.
2497 OPTIONS FOR TUNING THE CACHE
2498 -----------------------------------------------------------------------------
2501 NAME: cache no_cache
2504 LOC: Config.accessList.noCache
2506 A list of ACL elements which, if matched, cause the request to
2507 not be satisfied from the cache and the reply to not be cached.
2508 In other words, use this to force certain objects to never be cached.
2510 You must use the word 'DENY' to indicate the ACL names which should
2513 Default is to allow all to be cached
2515 #We recommend you to use the following two lines.
2516 acl QUERY urlpath_regex cgi-bin \?
2521 NAME: refresh_pattern
2522 TYPE: refreshpattern
2526 usage: refresh_pattern [-i] regex min percent max [options]
2528 By default, regular expressions are CASE-SENSITIVE. To make
2529 them case-insensitive, use the -i option.
2531 'Min' is the time (in minutes) an object without an explicit
2532 expiry time should be considered fresh. The recommended
2533 value is 0, any higher values may cause dynamic applications
2534 to be erroneously cached unless the application designer
2535 has taken the appropriate actions.
2537 'Percent' is a percentage of the objects age (time since last
2538 modification age) an object without explicit expiry time
2539 will be considered fresh.
2541 'Max' is an upper limit on how long objects without an explicit
2542 expiry time will be considered fresh.
2544 options: override-expire
2554 override-expire enforces min age even if the server
2555 sent a Expires: header. Doing this VIOLATES the HTTP
2556 standard. Enabling this feature could make you liable
2557 for problems which it causes.
2559 override-lastmod enforces min age even on objects
2560 that were modified recently.
2562 reload-into-ims changes client no-cache or ``reload''
2563 to If-Modified-Since requests. Doing this VIOLATES the
2564 HTTP standard. Enabling this feature could make you
2565 liable for problems which it causes.
2567 ignore-reload ignores a client no-cache or ``reload''
2568 header. Doing this VIOLATES the HTTP standard. Enabling
2569 this feature could make you liable for problems which
2572 ignore-no-cache ignores any ``Pragma: no-cache'' and
2573 ``Cache-control: no-cache'' headers received from a server.
2574 The HTTP RFC never allows the use of this (Pragma) header
2575 from a server, only a client, though plenty of servers
2578 ignore-no-store ignores any ``Cache-control: no-store''
2579 headers received from a server. Doing this VIOLATES
2580 the HTTP standard. Enabling this feature could make you
2581 liable for problems which it causes.
2583 ignore-private ignores any ``Cache-control: private''
2584 headers received from a server. Doing this VIOLATES
2585 the HTTP standard. Enabling this feature could make you
2586 liable for problems which it causes.
2588 ignore-auth caches responses to requests with authorization,
2589 as if the originserver had sent ``Cache-control: public''
2590 in the response header. Doing this VIOLATES the HTTP standard.
2591 Enabling this feature could make you liable for problems which
2594 refresh-ims causes squid to contact the origin server
2595 when a client issues an If-Modified-Since request. This
2596 ensures that the client will receive an updated version
2597 if one is available.
2599 Basically a cached object is:
2601 FRESH if expires < now, else STALE
2603 FRESH if lm-factor < percent, else STALE
2607 The refresh_pattern lines are checked in the order listed here.
2608 The first entry which matches is used. If none of the entries
2609 match the default will be used.
2611 Note, you must uncomment all the default lines if you want
2612 to change one. The default setting is only active if none is
2617 refresh_pattern ^ftp: 1440 20% 10080
2618 refresh_pattern ^gopher: 1440 0% 1440
2619 refresh_pattern . 0 20% 4320
2623 NAME: quick_abort_min
2627 LOC: Config.quickAbort.min
2630 NAME: quick_abort_max
2634 LOC: Config.quickAbort.max
2637 NAME: quick_abort_pct
2641 LOC: Config.quickAbort.pct
2643 The cache by default continues downloading aborted requests
2644 which are almost completed (less than 16 KB remaining). This
2645 may be undesirable on slow (e.g. SLIP) links and/or very busy
2646 caches. Impatient users may tie up file descriptors and
2647 bandwidth by repeatedly requesting and immediately aborting
2650 When the user aborts a request, Squid will check the
2651 quick_abort values to the amount of data transfered until
2654 If the transfer has less than 'quick_abort_min' KB remaining,
2655 it will finish the retrieval.
2657 If the transfer has more than 'quick_abort_max' KB remaining,
2658 it will abort the retrieval.
2660 If more than 'quick_abort_pct' of the transfer has completed,
2661 it will finish the retrieval.
2663 If you do not want any retrieval to continue after the client
2664 has aborted, set both 'quick_abort_min' and 'quick_abort_max'
2667 If you want retrievals to always continue if they are being
2668 cached set 'quick_abort_min' to '-1 KB'.
2671 NAME: read_ahead_gap
2672 COMMENT: buffer-size
2674 LOC: Config.readAheadGap
2677 The amount of data the cache will buffer ahead of what has been
2678 sent to the client when retrieving an object from another server.
2684 LOC: Config.negativeTtl
2687 Time-to-Live (TTL) for failed requests. Certain types of
2688 failures (such as "connection refused" and "404 Not Found") are
2689 negatively-cached for a configurable amount of time. The
2690 default is 5 minutes. Note that this is different from
2691 negative caching of DNS lookups.
2694 NAME: positive_dns_ttl
2697 LOC: Config.positiveDnsTtl
2700 Upper limit on how long Squid will cache positive DNS responses.
2701 Default is 6 hours (360 minutes). This directive must be set
2702 larger than negative_dns_ttl.
2705 NAME: negative_dns_ttl
2708 LOC: Config.negativeDnsTtl
2711 Time-to-Live (TTL) for negative caching of failed DNS lookups.
2712 This also sets the lower cache limit on positive lookups.
2713 Minimum value is 1 second, and it is not recommendable to go
2714 much below 10 seconds.
2717 NAME: range_offset_limit
2720 LOC: Config.rangeOffsetLimit
2723 Sets a upper limit on how far into the the file a Range request
2724 may be to cause Squid to prefetch the whole file. If beyond this
2725 limit Squid forwards the Range request as it is and the result
2728 This is to stop a far ahead range request (lets say start at 17MB)
2729 from making Squid fetch the whole object up to that point before
2730 sending anything to the client.
2732 A value of -1 causes Squid to always fetch the object from the
2733 beginning so it may cache the result. (2.0 style)
2735 A value of 0 causes Squid to never fetch more than the
2736 client requested. (default)
2739 NAME: minimum_expiry_time
2742 LOC: Config.minimum_expiry_time
2745 The minimum caching time according to (Expires - Date)
2746 Headers Squid honors if the object can't be revalidated
2747 defaults to 60 seconds. In reverse proxy enorinments it
2748 might be desirable to honor shorter object lifetimes. It
2749 is most likely better to make your server return a
2750 meaningful Last-Modified header however. In ESI environments
2751 where page fragments often have short lifetimes, this will
2752 often be best set to 0.
2755 NAME: store_avg_object_size
2759 LOC: Config.Store.avgObjectSize
2761 Average object size, used to estimate number of objects your
2762 cache can hold. The default is 13 KB.
2765 NAME: store_objects_per_bucket
2768 LOC: Config.Store.objectsPerBucket
2770 Target number of objects per bucket in the store hash table.
2771 Lowering this value increases the total number of buckets and
2772 also the storage maintenance rate. The default is 20.
2777 -----------------------------------------------------------------------------
2780 NAME: request_header_max_size
2784 LOC: Config.maxRequestHeaderSize
2786 This specifies the maximum size for HTTP headers in a request.
2787 Request headers are usually relatively small (about 512 bytes).
2788 Placing a limit on the request header size will catch certain
2789 bugs (for example with persistent connections) and possibly
2790 buffer-overflow or denial-of-service attacks.
2793 NAME: reply_header_max_size
2797 LOC: Config.maxReplyHeaderSize
2799 This specifies the maximum size for HTTP headers in a reply.
2800 Reply headers are usually relatively small (about 512 bytes).
2801 Placing a limit on the reply header size will catch certain
2802 bugs (for example with persistent connections) and possibly
2803 buffer-overflow or denial-of-service attacks.
2806 NAME: request_body_max_size
2810 LOC: Config.maxRequestBodySize
2812 This specifies the maximum size for an HTTP request body.
2813 In other words, the maximum size of a PUT/POST request.
2814 A user who attempts to send a request with a body larger
2815 than this limit receives an "Invalid Request" error message.
2816 If you set this parameter to a zero (the default), there will
2817 be no limit imposed.
2823 LOC: Config.accessList.brokenPosts
2825 A list of ACL elements which, if matched, causes Squid to send
2826 an extra CRLF pair after the body of a PUT/POST request.
2828 Some HTTP servers has broken implementations of PUT/POST,
2829 and rely on an extra CRLF pair sent by some WWW clients.
2831 Quote from RFC2616 section 4.1 on this matter:
2833 Note: certain buggy HTTP/1.0 client implementations generate an
2834 extra CRLF's after a POST request. To restate what is explicitly
2835 forbidden by the BNF, an HTTP/1.1 client must not preface or follow
2836 a request with an extra CRLF.
2839 acl buggy_server url_regex ^http://....
2840 broken_posts allow buggy_server
2844 IFDEF: HTTP_VIOLATIONS
2848 LOC: Config.onoff.via
2850 If set (default), Squid will include a Via header in requests and
2851 replies as required by RFC2616.
2857 LOC: Config.onoff.ie_refresh
2860 Microsoft Internet Explorer up until version 5.5 Service
2861 Pack 1 has an issue with transparent proxies, wherein it
2862 is impossible to force a refresh. Turning this on provides
2863 a partial fix to the problem, by causing all IMS-REFRESH
2864 requests from older IE versions to check the origin server
2865 for fresh content. This reduces hit ratio by some amount
2866 (~10% in my experience), but allows users to actually get
2867 fresh content when they want it. Note because Squid
2868 cannot tell if the user is using 5.5 or 5.5SP1, the behavior
2869 of 5.5 is unchanged from old versions of Squid (i.e. a
2870 forced refresh is impossible). Newer versions of IE will,
2871 hopefully, continue to have the new behavior and will be
2872 handled based on that assumption. This option defaults to
2873 the old Squid behavior, which is better for hit ratios but
2874 worse for clients using IE, if they need to be able to
2875 force fresh content.
2878 NAME: vary_ignore_expire
2881 LOC: Config.onoff.vary_ignore_expire
2884 Many HTTP servers supporting Vary gives such objects
2885 immediate expiry time with no cache-control header
2886 when requested by a HTTP/1.0 client. This option
2887 enables Squid to ignore such expiry times until
2888 HTTP/1.1 is fully implemented.
2889 WARNING: This may eventually cause some varying
2890 objects not intended for caching to get cached.
2893 NAME: extension_methods
2895 LOC: Config.ext_methods
2898 Squid only knows about standardized HTTP request methods.
2899 You can add up to 20 additional "extension" methods here.
2902 NAME: request_entities
2904 LOC: Config.onoff.request_entities
2907 Squid defaults to deny GET and HEAD requests with request entities,
2908 as the meaning of such requests are undefined in the HTTP standard
2909 even if not explicitly forbidden.
2911 Set this directive to on if you have clients which insists
2912 on sending request entities in GET or HEAD requests. But be warned
2913 that there is server software (both proxies and web servers) which
2914 can fail to properly process this kind of request which may make you
2915 vulnerable to cache pollution attacks if enabled.
2918 NAME: request_header_access
2919 IFDEF: HTTP_VIOLATIONS
2920 TYPE: http_header_access[]
2921 LOC: Config.request_header_access
2924 Usage: request_header_access header_name allow|deny [!]aclname ...
2926 WARNING: Doing this VIOLATES the HTTP standard. Enabling
2927 this feature could make you liable for problems which it
2930 This option replaces the old 'anonymize_headers' and the
2931 older 'http_anonymizer' option with something that is much
2932 more configurable. This new method creates a list of ACLs
2933 for each header, allowing you very fine-tuned header
2936 This option only applies to request headers, i.e., from the
2937 client to the server.
2939 You can only specify known headers for the header name.
2940 Other headers are reclassified as 'Other'. You can also
2941 refer to all the headers with 'All'.
2943 For example, to achieve the same behavior as the old
2944 'http_anonymizer standard' option, you should use:
2946 request_header_access From deny all
2947 request_header_access Referer deny all
2948 request_header_access Server deny all
2949 request_header_access User-Agent deny all
2950 request_header_access WWW-Authenticate deny all
2951 request_header_access Link deny all
2953 Or, to reproduce the old 'http_anonymizer paranoid' feature
2956 request_header_access Allow allow all
2957 request_header_access Authorization allow all
2958 request_header_access WWW-Authenticate allow all
2959 request_header_access Proxy-Authorization allow all
2960 request_header_access Proxy-Authenticate allow all
2961 request_header_access Cache-Control allow all
2962 request_header_access Content-Encoding allow all
2963 request_header_access Content-Length allow all
2964 request_header_access Content-Type allow all
2965 request_header_access Date allow all
2966 request_header_access Expires allow all
2967 request_header_access Host allow all
2968 request_header_access If-Modified-Since allow all
2969 request_header_access Last-Modified allow all
2970 request_header_access Location allow all
2971 request_header_access Pragma allow all
2972 request_header_access Accept allow all
2973 request_header_access Accept-Charset allow all
2974 request_header_access Accept-Encoding allow all
2975 request_header_access Accept-Language allow all
2976 request_header_access Content-Language allow all
2977 request_header_access Mime-Version allow all
2978 request_header_access Retry-After allow all
2979 request_header_access Title allow all
2980 request_header_access Connection allow all
2981 request_header_access Proxy-Connection allow all
2982 request_header_access All deny all
2984 although many of those are HTTP reply headers, and so should be
2985 controlled with the reply_header_access directive.
2987 By default, all headers are allowed (no anonymizing is
2991 NAME: reply_header_access
2992 IFDEF: HTTP_VIOLATIONS
2993 TYPE: http_header_access[]
2994 LOC: Config.reply_header_access
2997 Usage: reply_header_access header_name allow|deny [!]aclname ...
2999 WARNING: Doing this VIOLATES the HTTP standard. Enabling
3000 this feature could make you liable for problems which it
3003 This option only applies to reply headers, i.e., from the
3004 server to the client.
3006 This is the same as request_header_access, but in the other
3009 This option replaces the old 'anonymize_headers' and the
3010 older 'http_anonymizer' option with something that is much
3011 more configurable. This new method creates a list of ACLs
3012 for each header, allowing you very fine-tuned header
3015 You can only specify known headers for the header name.
3016 Other headers are reclassified as 'Other'. You can also
3017 refer to all the headers with 'All'.
3019 For example, to achieve the same behavior as the old
3020 'http_anonymizer standard' option, you should use:
3022 reply_header_access From deny all
3023 reply_header_access Referer deny all
3024 reply_header_access Server deny all
3025 reply_header_access User-Agent deny all
3026 reply_header_access WWW-Authenticate deny all
3027 reply_header_access Link deny all
3029 Or, to reproduce the old 'http_anonymizer paranoid' feature
3032 reply_header_access Allow allow all
3033 reply_header_access Authorization allow all
3034 reply_header_access WWW-Authenticate allow all
3035 reply_header_access Proxy-Authorization allow all
3036 reply_header_access Proxy-Authenticate allow all
3037 reply_header_access Cache-Control allow all
3038 reply_header_access Content-Encoding allow all
3039 reply_header_access Content-Length allow all
3040 reply_header_access Content-Type allow all
3041 reply_header_access Date allow all
3042 reply_header_access Expires allow all
3043 reply_header_access Host allow all
3044 reply_header_access If-Modified-Since allow all
3045 reply_header_access Last-Modified allow all
3046 reply_header_access Location allow all
3047 reply_header_access Pragma allow all
3048 reply_header_access Accept allow all
3049 reply_header_access Accept-Charset allow all
3050 reply_header_access Accept-Encoding allow all
3051 reply_header_access Accept-Language allow all
3052 reply_header_access Content-Language allow all
3053 reply_header_access Mime-Version allow all
3054 reply_header_access Retry-After allow all
3055 reply_header_access Title allow all
3056 reply_header_access Connection allow all
3057 reply_header_access Proxy-Connection allow all
3058 reply_header_access All deny all
3060 although the HTTP request headers won't be usefully controlled
3061 by this directive -- see request_header_access for details.
3063 By default, all headers are allowed (no anonymizing is
3067 NAME: header_replace
3068 IFDEF: HTTP_VIOLATIONS
3069 TYPE: http_header_replace[]
3070 LOC: Config.request_header_access
3073 Usage: header_replace header_name message
3074 Example: header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
3076 This option allows you to change the contents of headers
3077 denied with header_access above, by replacing them with
3078 some fixed string. This replaces the old fake_user_agent
3081 This only applies to request headers, not reply headers.
3083 By default, headers are removed if denied.
3086 NAME: relaxed_header_parser
3087 COMMENT: on|off|warn
3089 LOC: Config.onoff.relaxed_header_parser
3092 In the default "on" setting Squid accepts certain forms
3093 of non-compliant HTTP messages where it is unambiguous
3094 what the sending application intended even if the message
3095 is not correctly formatted. The messages is then normalized
3096 to the correct form when forwarded by Squid.
3098 If set to "warn" then a warning will be emitted in cache.log
3099 each time such HTTP error is encountered.
3101 If set to "off" then such HTTP errors will cause the request
3102 or response to be rejected.
3107 -----------------------------------------------------------------------------
3110 NAME: forward_timeout
3113 LOC: Config.Timeout.forward
3116 This parameter specifies how long Squid should at most attempt in
3117 finding a forwarding path for the request before giving up.
3120 NAME: connect_timeout
3123 LOC: Config.Timeout.connect
3126 This parameter specifies how long to wait for the TCP connect to
3127 the requested server or peer to complete before Squid should
3128 attempt to find another path where to forward the request.
3131 NAME: peer_connect_timeout
3134 LOC: Config.Timeout.peer_connect
3137 This parameter specifies how long to wait for a pending TCP
3138 connection to a peer cache. The default is 30 seconds. You
3139 may also set different timeout values for individual neighbors
3140 with the 'connect-timeout' option on a 'cache_peer' line.
3146 LOC: Config.Timeout.read
3149 The read_timeout is applied on server-side connections. After
3150 each successful read(), the timeout will be extended by this
3151 amount. If no data is read again after this amount of time,
3152 the request is aborted and logged with ERR_READ_TIMEOUT. The
3153 default is 15 minutes.
3156 NAME: request_timeout
3158 LOC: Config.Timeout.request
3161 How long to wait for an HTTP request after initial
3162 connection establishment.
3165 NAME: persistent_request_timeout
3167 LOC: Config.Timeout.persistent_request
3170 How long to wait for the next HTTP request on a persistent
3171 connection after the previous request completes.
3174 NAME: client_lifetime
3177 LOC: Config.Timeout.lifetime
3180 The maximum amount of time a client (browser) is allowed to
3181 remain connected to the cache process. This protects the Cache
3182 from having a lot of sockets (and hence file descriptors) tied up
3183 in a CLOSE_WAIT state from remote clients that go away without
3184 properly shutting down (either because of a network failure or
3185 because of a poor client implementation). The default is one
3188 NOTE: The default value is intended to be much larger than any
3189 client would ever need to be connected to your cache. You
3190 should probably change client_lifetime only as a last resort.
3191 If you seem to have many client connections tying up
3192 filedescriptors, we recommend first tuning the read_timeout,
3193 request_timeout, persistent_request_timeout and quick_abort values.
3196 NAME: half_closed_clients
3198 LOC: Config.onoff.half_closed_clients
3201 Some clients may shutdown the sending side of their TCP
3202 connections, while leaving their receiving sides open. Sometimes,
3203 Squid can not tell the difference between a half-closed and a
3204 fully-closed TCP connection. By default, half-closed client
3205 connections are kept open until a read(2) or write(2) on the
3206 socket returns an error. Change this option to 'off' and Squid
3207 will immediately close client connections when read(2) returns
3208 "no more data to read."
3213 LOC: Config.Timeout.pconn
3216 Timeout for idle persistent connections to servers and other
3223 LOC: Config.Timeout.ident
3226 Maximum time to wait for IDENT lookups to complete.
3228 If this is too high, and you enabled IDENT lookups from untrusted
3229 users, you might be susceptible to denial-of-service by having
3230 many ident requests going at once.
3233 NAME: shutdown_lifetime
3236 LOC: Config.shutdownLifetime
3239 When SIGTERM or SIGHUP is received, the cache is put into
3240 "shutdown pending" mode until all active sockets are closed.
3241 This value is the lifetime to set for all open descriptors
3242 during shutdown mode. Any active clients after this many
3243 seconds will receive a 'timeout' message.
3247 ADMINISTRATIVE PARAMETERS
3248 -----------------------------------------------------------------------------
3254 LOC: Config.adminEmail
3256 Email-address of local cache manager who will receive
3257 mail if the cache dies. The default is "webmaster."
3263 LOC: Config.EmailFrom
3265 From: email-address for mail sent when the cache dies.
3266 The default is to use 'appname@unique_hostname'.
3267 Default appname value is "squid", can be changed into
3268 src/globals.h before building squid.
3274 LOC: Config.EmailProgram
3276 Email program used to send mail if the cache dies.
3277 The default is "mail". The specified program must comply
3278 with the standard Unix mail syntax:
3279 mail-program recipient < mailfile
3281 Optional command line options can be specified.
3284 NAME: cache_effective_user
3286 DEFAULT: @DEFAULT_CACHE_EFFECTIVE_USER@
3287 LOC: Config.effectiveUser
3289 If you start Squid as root, it will change its effective/real
3290 UID/GID to the user specified below. The default is to change
3291 to UID of @DEFAULT_CACHE_EFFECTIVE_USER@.
3292 see also; cache_effective_group
3295 NAME: cache_effective_group
3298 LOC: Config.effectiveGroup
3300 Squid sets the GID to the effective user's default group ID
3301 (taken from the password file) and supplementary group list
3302 from the groups membership.
3304 If you want Squid to run with a specific GID regardless of
3305 the group memberships of the effective user then set this
3306 to the group (or GID) you want Squid to run as. When set
3307 all other group privileges of the effective user are ignored
3308 and only this GID is effective. If Squid is not started as
3309 root the user starting Squid MUST be member of the specified
3312 This option is not recommended by the Squid Team.
3313 Our preference is for administrators to configure a secure
3314 user account for squid with UID/GID matching system policies.
3317 NAME: httpd_suppress_version_string
3321 LOC: Config.onoff.httpd_suppress_version_string
3323 Suppress Squid version string info in HTTP headers and HTML error pages.
3326 NAME: visible_hostname
3328 LOC: Config.visibleHostname
3331 If you want to present a special hostname in error messages, etc,
3332 define this. Otherwise, the return value of gethostname()
3333 will be used. If you have multiple caches in a cluster and
3334 get errors about IP-forwarding you must set them to have individual
3335 names with this setting.
3338 NAME: unique_hostname
3340 LOC: Config.uniqueHostname
3343 If you want to have multiple machines with the same
3344 'visible_hostname' you must give each machine a different
3345 'unique_hostname' so forwarding loops can be detected.
3348 NAME: hostname_aliases
3350 LOC: Config.hostnameAliases
3353 A list of other DNS names your cache has.
3357 OPTIONS FOR THE CACHE REGISTRATION SERVICE
3358 -----------------------------------------------------------------------------
3360 This section contains parameters for the (optional) cache
3361 announcement service. This service is provided to help
3362 cache administrators locate one another in order to join or
3363 create cache hierarchies.
3365 An 'announcement' message is sent (via UDP) to the registration
3366 service by Squid. By default, the announcement message is NOT
3367 SENT unless you enable it with 'announce_period' below.
3369 The announcement message includes your hostname, plus the
3370 following information from this configuration file:
3376 All current information is processed regularly and made
3377 available on the Web at http://www.ircache.net/Cache/Tracker/.
3380 NAME: announce_period
3382 LOC: Config.Announce.period
3385 This is how frequently to send cache announcements. The
3386 default is `0' which disables sending the announcement
3389 To enable announcing your cache, just uncomment the line
3393 #To enable announcing your cache, just uncomment the line below.
3394 #announce_period 1 day
3400 DEFAULT: tracker.ircache.net
3401 LOC: Config.Announce.host
3407 LOC: Config.Announce.file
3413 LOC: Config.Announce.port
3415 announce_host and announce_port set the hostname and port
3416 number where the registration message will be sent.
3418 Hostname will default to 'tracker.ircache.net' and port will
3419 default default to 3131. If the 'filename' argument is given,
3420 the contents of that file will be included in the announce
3425 HTTPD-ACCELERATOR OPTIONS
3426 -----------------------------------------------------------------------------
3429 NAME: httpd_accel_surrogate_id
3430 IFDEF: USE_SQUID_ESI
3432 LOC: Config.Accel.surrogate_id
3435 Surrogates (http://www.esi.org/architecture_spec_1.0.html)
3436 need an identification token to allow control targeting. Because
3437 a farm of surrogates may all perform the same tasks, they may share
3438 an identification token.
3441 NAME: http_accel_surrogate_remote
3442 IFDEF: USE_SQUID_ESI
3446 LOC: Config.onoff.surrogate_is_remote
3448 Remote surrogates (such as those in a CDN) honour Surrogate-Control: no-store-remote.
3449 Set this to on to have squid behave as a remote surrogate.
3453 IFDEF: USE_SQUID_ESI
3454 COMMENT: libxml2|expat|custom
3456 LOC: ESIParser::Type
3459 ESI markup is not strictly XML compatible. The custom ESI parser
3460 will give higher performance, but cannot handle non ASCII character
3465 DELAY POOL PARAMETERS
3466 -----------------------------------------------------------------------------
3470 TYPE: delay_pool_count
3475 This represents the number of delay pools to be used. For example,
3476 if you have one class 2 delay pool and one class 3 delays pool, you
3477 have a total of 2 delay pools.
3481 TYPE: delay_pool_class
3486 This defines the class of each delay pool. There must be exactly one
3487 delay_class line for each delay pool. For example, to define two
3488 delay pools, one of class 2 and one of class 3, the settings above
3492 delay_pools 4 # 4 delay pools
3493 delay_class 1 2 # pool 1 is a class 2 pool
3494 delay_class 2 3 # pool 2 is a class 3 pool
3495 delay_class 3 4 # pool 3 is a class 4 pool
3496 delay_class 4 5 # pool 4 is a class 5 pool
3498 The delay pool classes are:
3500 class 1 Everything is limited by a single aggregate
3503 class 2 Everything is limited by a single aggregate
3504 bucket as well as an "individual" bucket chosen
3505 from bits 25 through 32 of the IP address.
3507 class 3 Everything is limited by a single aggregate
3508 bucket as well as a "network" bucket chosen
3509 from bits 17 through 24 of the IP address and a
3510 "individual" bucket chosen from bits 17 through
3511 32 of the IP address.
3513 class 4 Everything in a class 3 delay pool, with an
3514 additional limit on a per user basis. This
3515 only takes effect if the username is established
3516 in advance - by forcing authentication in your
3519 class 5 Requests are grouped according their tag (see
3520 external_acl's tag= reply).
3522 NOTE: If an IP address is a.b.c.d
3523 -> bits 25 through 32 are "d"
3524 -> bits 17 through 24 are "c"
3525 -> bits 17 through 32 are "c * 256 + d"
3529 TYPE: delay_pool_access
3534 This is used to determine which delay pool a request falls into.
3536 delay_access is sorted per pool and the matching starts with pool 1,
3537 then pool 2, ..., and finally pool N. The first delay pool where the
3538 request is allowed is selected for the request. If it does not allow
3539 the request to any pool then the request is not delayed (default).
3541 For example, if you want some_big_clients in delay
3542 pool 1 and lotsa_little_clients in delay pool 2:
3545 delay_access 1 allow some_big_clients
3546 delay_access 1 deny all
3547 delay_access 2 allow lotsa_little_clients
3548 delay_access 2 deny all
3549 delay_access 3 allow authenticated_clients
3552 NAME: delay_parameters
3553 TYPE: delay_pool_rates
3558 This defines the parameters for a delay pool. Each delay pool has
3559 a number of "buckets" associated with it, as explained in the
3560 description of delay_class. For a class 1 delay pool, the syntax is:
3562 delay_parameters pool aggregate
3564 For a class 2 delay pool:
3566 delay_parameters pool aggregate individual
3568 For a class 3 delay pool:
3570 delay_parameters pool aggregate network individual
3572 For a class 4 delay pool:
3574 delay_parameters pool aggregate network individual user
3576 For a class 5 delay pool:
3578 delay_parameters pool tag
3580 The variables here are:
3582 pool a pool number - ie, a number between 1 and the
3583 number specified in delay_pools as used in
3586 aggregate the "delay parameters" for the aggregate bucket
3589 individual the "delay parameters" for the individual
3590 buckets (class 2, 3).
3592 network the "delay parameters" for the network buckets
3595 user the delay parameters for the user buckets
3598 tag the delay parameters for the tag buckets
3601 A pair of delay parameters is written restore/maximum, where restore is
3602 the number of bytes (not bits - modem and network speeds are usually
3603 quoted in bits) per second placed into the bucket, and maximum is the
3604 maximum number of bytes which can be in the bucket at any time.
3606 For example, if delay pool number 1 is a class 2 delay pool as in the
3607 above example, and is being used to strictly limit each host to 64kbps
3608 (plus overheads), with no overall limit, the line is:
3610 delay_parameters 1 -1/-1 8000/8000
3612 Note that the figure -1 is used to represent "unlimited".
3614 And, if delay pool number 2 is a class 3 delay pool as in the above
3615 example, and you want to limit it to a total of 256kbps (strict limit)
3616 with each 8-bit network permitted 64kbps (strict limit) and each
3617 individual host permitted 4800bps with a bucket maximum size of 64kb
3618 to permit a decent web page to be downloaded at a decent speed
3619 (if the network is not being limited due to overuse) but slow down
3620 large downloads more significantly:
3622 delay_parameters 2 32000/32000 8000/8000 600/8000
3624 There must be one delay_parameters line for each delay pool.
3626 Finally, for a class 4 delay pool as in the example - each user will
3627 be limited to 128Kb no matter how many workstations they are logged into.:
3629 delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000
3632 NAME: delay_initial_bucket_level
3633 COMMENT: (percent, 0-100)
3637 LOC: Config.Delay.initial
3639 The initial bucket percentage is used to determine how much is put
3640 in each bucket when squid starts, is reconfigured, or first notices
3641 a host accessing it (in class 2 and class 3, individual hosts and
3642 networks only have buckets associated with them once they have been
3647 WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS
3648 -----------------------------------------------------------------------------
3653 LOC: Config.Wccp.router
3658 TYPE: IPAddress_list
3659 LOC: Config.Wccp2.router
3663 Use this option to define your WCCP ``home'' router for
3666 wccp_router supports a single WCCP(v1) router
3668 wccp2_router supports multiple WCCPv2 routers
3670 only one of the two may be used at the same time and defines
3671 which version of WCCP to use.
3676 LOC: Config.Wccp.version
3680 This directive is only relevant if you need to set up WCCP(v1)
3681 to some very old and end-of-life Cisco routers. In all other
3682 setups it must be left unset or at the default setting.
3683 It defines an internal version in the WCCP(v1) protocol,
3684 with version 4 being the officially documented protocol.
3686 According to some users, Cisco IOS 11.2 and earlier only
3687 support WCCP version 3. If you're using that or an earlier
3688 version of IOS, you may need to change this value to 3, otherwise
3689 do not specify this parameter.
3692 NAME: wccp2_rebuild_wait
3694 LOC: Config.Wccp2.rebuildwait
3698 If this is enabled Squid will wait for the cache dir rebuild to finish
3699 before sending the first wccp2 HereIAm packet
3702 NAME: wccp2_forwarding_method
3704 LOC: Config.Wccp2.forwarding_method
3708 WCCP2 allows the setting of forwarding methods between the
3709 router/switch and the cache. Valid values are as follows:
3711 1 - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
3712 2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
3714 Currently (as of IOS 12.4) cisco routers only support GRE.
3715 Cisco switches only support the L2 redirect assignment method.
3718 NAME: wccp2_return_method
3720 LOC: Config.Wccp2.return_method
3724 WCCP2 allows the setting of return methods between the
3725 router/switch and the cache for packets that the cache
3726 decides not to handle. Valid values are as follows:
3728 1 - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
3729 2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
3731 Currently (as of IOS 12.4) cisco routers only support GRE.
3732 Cisco switches only support the L2 redirect assignment.
3734 If the "ip wccp redirect exclude in" command has been
3735 enabled on the cache interface, then it is still safe for
3736 the proxy server to use a l2 redirect method even if this
3737 option is set to GRE.
3740 NAME: wccp2_assignment_method
3742 LOC: Config.Wccp2.assignment_method
3746 WCCP2 allows the setting of methods to assign the WCCP hash
3747 Valid values are as follows:
3752 As a general rule, cisco routers support the hash assignment method
3753 and cisco switches support the mask assignment method.
3758 LOC: Config.Wccp2.info
3760 DEFAULT_IF_NONE: standard 0
3763 WCCP2 allows for multiple traffic services. There are two
3764 types: "standard" and "dynamic". The standard type defines
3765 one service id - http (id 0). The dynamic service ids can be from
3766 51 to 255 inclusive. In order to use a dynamic service id
3767 one must define the type of traffic to be redirected; this is done
3768 using the wccp2_service_info option.
3770 The "standard" type does not require a wccp2_service_info option,
3771 just specifying the service id will suffice.
3773 MD5 service authentication can be enabled by adding
3774 "password=<password>" to the end of this service declaration.
3778 wccp2_service standard 0 # for the 'web-cache' standard service
3779 wccp2_service dynamic 80 # a dynamic service type which will be
3780 # fleshed out with subsequent options.
3781 wccp2_service standard 0 password=foo
3785 NAME: wccp2_service_info
3786 TYPE: wccp2_service_info
3787 LOC: Config.Wccp2.info
3791 Dynamic WCCPv2 services require further information to define the
3792 traffic you wish to have diverted.
3796 wccp2_service_info <id> protocol=<protocol> flags=<flag>,<flag>..
3797 priority=<priority> ports=<port>,<port>..
3799 The relevant WCCPv2 flags:
3800 + src_ip_hash, dst_ip_hash
3801 + source_port_hash, dest_port_hash
3802 + src_ip_alt_hash, dst_ip_alt_hash
3803 + src_port_alt_hash, dst_port_alt_hash
3806 The port list can be one to eight entries.
3810 wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source
3811 priority=240 ports=80
3813 Note: the service id must have been defined by a previous
3814 'wccp2_service dynamic <id>' entry.
3819 LOC: Config.Wccp2.weight
3823 Each cache server gets assigned a set of the destination
3824 hash proportional to their weight.
3829 LOC: Config.Wccp.address
3835 LOC: Config.Wccp2.address
3839 Use this option if you require WCCP to use a specific
3842 The default behavior is to not bind to any specific address.
3846 PERSISTENT CONNECTION HANDLING
3847 -----------------------------------------------------------------------------
3849 Also see "pconn_timeout" in the TIMEOUTS section
3852 NAME: client_persistent_connections
3854 LOC: Config.onoff.client_pconns
3858 NAME: server_persistent_connections
3860 LOC: Config.onoff.server_pconns
3863 Persistent connection support for clients and servers. By
3864 default, Squid uses persistent connections (when allowed)
3865 with its clients and servers. You can use these options to
3866 disable persistent connections with clients and/or servers.
3869 NAME: persistent_connection_after_error
3871 LOC: Config.onoff.error_pconns
3874 With this directive the use of persistent connections after
3875 HTTP errors can be disabled. Useful if you have clients
3876 who fail to handle errors on persistent connections proper.
3879 NAME: detect_broken_pconn
3881 LOC: Config.onoff.detect_broken_server_pconns
3884 Some servers have been found to incorrectly signal the use
3885 of HTTP/1.0 persistent connections even on replies not
3886 compatible, causing significant delays. This server problem
3887 has mostly been seen on redirects.
3889 By enabling this directive Squid attempts to detect such
3890 broken replies and automatically assume the reply is finished
3891 after 10 seconds timeout.
3895 CACHE DIGEST OPTIONS
3896 -----------------------------------------------------------------------------
3899 NAME: digest_generation
3900 IFDEF: USE_CACHE_DIGESTS
3902 LOC: Config.onoff.digest_generation
3905 This controls whether the server will generate a Cache Digest
3906 of its contents. By default, Cache Digest generation is
3907 enabled if Squid is compiled with --enable-cache-digests defined.
3910 NAME: digest_bits_per_entry
3911 IFDEF: USE_CACHE_DIGESTS
3913 LOC: Config.digest.bits_per_entry
3916 This is the number of bits of the server's Cache Digest which
3917 will be associated with the Digest entry for a given HTTP
3918 Method and URL (public key) combination. The default is 5.
3921 NAME: digest_rebuild_period
3922 IFDEF: USE_CACHE_DIGESTS
3925 LOC: Config.digest.rebuild_period
3928 This is the wait time between Cache Digest rebuilds.
3931 NAME: digest_rewrite_period
3933 IFDEF: USE_CACHE_DIGESTS
3935 LOC: Config.digest.rewrite_period
3938 This is the wait time between Cache Digest writes to
3942 NAME: digest_swapout_chunk_size
3945 IFDEF: USE_CACHE_DIGESTS
3946 LOC: Config.digest.swapout_chunk_size
3949 This is the number of bytes of the Cache Digest to write to
3950 disk at a time. It defaults to 4096 bytes (4KB), the Squid
3954 NAME: digest_rebuild_chunk_percentage
3955 COMMENT: (percent, 0-100)
3956 IFDEF: USE_CACHE_DIGESTS
3958 LOC: Config.digest.rebuild_chunk_percentage
3961 This is the percentage of the Cache Digest to be scanned at a
3962 time. By default it is set to 10% of the Cache Digest.
3967 -----------------------------------------------------------------------------
3972 LOC: Config.Port.snmp
3976 The port number where Squid listens for SNMP requests. To enable
3977 SNMP support set this to a suitable port number. Port number
3978 3401 is often used for the Squid SNMP agent. By default it's
3979 set to "0" (disabled)
3987 LOC: Config.accessList.snmp
3989 DEFAULT_IF_NONE: deny all
3992 Allowing or denying access to the SNMP port.
3994 All access to the agent is denied by default.
3997 snmp_access allow|deny [!]aclname ...
4000 snmp_access allow snmppublic localhost
4001 snmp_access deny all
4004 NAME: snmp_incoming_address
4006 LOC: Config.Addrs.snmp_incoming
4010 NAME: snmp_outgoing_address
4012 LOC: Config.Addrs.snmp_outgoing
4013 DEFAULT: 255.255.255.255
4016 Just like 'udp_incoming_address' above, but for the SNMP port.
4018 snmp_incoming_address is used for the SNMP socket receiving
4019 messages from SNMP agents.
4020 snmp_outgoing_address is used for SNMP packets returned to SNMP
4023 The default snmp_incoming_address (0.0.0.0) is to listen on all
4024 available network interfaces.
4026 If snmp_outgoing_address is set to 255.255.255.255 (the default)
4027 it will use the same socket as snmp_incoming_address. Only
4028 change this if you want to have SNMP replies sent using another
4029 address than where this Squid listens for SNMP queries.
4031 NOTE, snmp_incoming_address and snmp_outgoing_address can not have
4032 the same value since they both use port 3401.
4037 -----------------------------------------------------------------------------
4040 NAME: icp_port udp_port
4043 LOC: Config.Port.icp
4045 The port number where Squid sends and receives ICP queries to
4046 and from neighbor caches. The standard UDP port for ICP is 3130.
4047 Default is disabled (0).
4049 icp_port @DEFAULT_ICP_PORT@
4057 LOC: Config.Port.htcp
4059 The port number where Squid sends and receives HTCP queries to
4060 and from neighbor caches. To turn it on you want to set it to
4061 4827. By default it is set to "0" (disabled).
4067 NAME: log_icp_queries
4071 LOC: Config.onoff.log_udp
4073 If set, ICP queries are logged to access.log. You may wish
4074 do disable this if your ICP load is VERY high to speed things
4075 up or to simplify log analysis.
4078 NAME: udp_incoming_address
4080 LOC:Config.Addrs.udp_incoming
4083 udp_incoming_address is used for UDP packets received from other
4086 The default behavior is to not bind to any specific address.
4088 Only change this if you want to have all UDP queries received on
4089 a specific interface/address.
4091 NOTE: udp_incoming_address is used by the ICP, HTCP, and DNS
4092 modules. Altering it will affect all of them in the same manner.
4094 see also; udp_outgoing_address
4096 NOTE, udp_incoming_address and udp_outgoing_address can not
4097 have the same value since they both use the same port.
4100 NAME: udp_outgoing_address
4102 LOC: Config.Addrs.udp_outgoing
4103 DEFAULT: 255.255.255.255
4105 udp_outgoing_address is used for UDP packets sent out to other
4108 The default behavior is to not bind to any specific address.
4110 Instead it will use the same socket as udp_incoming_address.
4111 Only change this if you want to have UDP queries sent using another
4112 address than where this Squid listens for UDP queries from other
4115 NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS
4116 modules. Altering it will affect all of them in the same manner.
4118 see also; udp_incoming_address
4120 NOTE, udp_incoming_address and udp_outgoing_address can not
4121 have the same value since they both use the same port.
4128 LOC: Config.onoff.icp_hit_stale
4130 If you want to return ICP_HIT for stale cache objects, set this
4131 option to 'on'. If you have sibling relationships with caches
4132 in other administrative domains, this should be 'off'. If you only
4133 have sibling relationships with caches under your control,
4134 it is probably okay to set this to 'on'.
4135 If set to 'on', your siblings should use the option "allow-miss"
4136 on their cache_peer lines for connecting to you.
4139 NAME: minimum_direct_hops
4142 LOC: Config.minDirectHops
4144 If using the ICMP pinging stuff, do direct fetches for sites
4145 which are no more than this many hops away.
4148 NAME: minimum_direct_rtt
4151 LOC: Config.minDirectRtt
4153 If using the ICMP pinging stuff, do direct fetches for sites
4154 which are no more than this many rtt milliseconds away.
4160 LOC: Config.Netdb.low
4166 LOC: Config.Netdb.high
4168 The low and high water marks for the ICMP measurement
4169 database. These are counts, not percents. The defaults are
4170 900 and 1000. When the high water mark is reached, database
4171 entries will be deleted until the low mark is reached.
4174 NAME: netdb_ping_period
4176 LOC: Config.Netdb.period
4179 The minimum period for measuring a site. There will be at
4180 least this much delay between successive pings to the same
4181 network. The default is five minutes.
4188 LOC: Config.onoff.query_icmp
4190 If you want to ask your peers to include ICMP data in their ICP
4191 replies, enable this option.
4193 If your peer has configured Squid (during compilation) with
4194 '--enable-icmp' that peer will send ICMP pings to origin server
4195 sites of the URLs it receives. If you enable this option the
4196 ICP replies from that peer will include the ICMP data (if available).
4197 Then, when choosing a parent cache, Squid will choose the parent with
4198 the minimal RTT to the origin server. When this happens, the
4199 hierarchy field of the access.log will be
4200 "CLOSEST_PARENT_MISS". This option is off by default.
4203 NAME: test_reachability
4207 LOC: Config.onoff.test_reachability
4209 When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
4210 instead of ICP_MISS if the target host is NOT in the ICMP
4211 database, or has a zero RTT.
4214 NAME: icp_query_timeout
4218 LOC: Config.Timeout.icp_query
4220 Normally Squid will automatically determine an optimal ICP
4221 query timeout value based on the round-trip-time of recent ICP
4222 queries. If you want to override the value determined by
4223 Squid, set this 'icp_query_timeout' to a non-zero value. This
4224 value is specified in MILLISECONDS, so, to use a 2-second
4225 timeout (the old default), you would write:
4227 icp_query_timeout 2000
4230 NAME: maximum_icp_query_timeout
4234 LOC: Config.Timeout.icp_query_max
4236 Normally the ICP query timeout is determined dynamically. But
4237 sometimes it can lead to very large values (say 5 seconds).
4238 Use this option to put an upper limit on the dynamic timeout
4239 value. Do NOT use this option to always use a fixed (instead
4240 of a dynamic) timeout value. To set a fixed timeout see the
4241 'icp_query_timeout' directive.
4244 NAME: minimum_icp_query_timeout
4248 LOC: Config.Timeout.icp_query_min
4250 Normally the ICP query timeout is determined dynamically. But
4251 sometimes it can lead to very small timeouts, even lower than
4252 the normal latency variance on your link due to traffic.
4253 Use this option to put an lower limit on the dynamic timeout
4254 value. Do NOT use this option to always use a fixed (instead
4255 of a dynamic) timeout value. To set a fixed timeout see the
4256 'icp_query_timeout' directive.
4259 NAME: background_ping_rate
4263 LOC: Config.backgroundPingRate
4265 Controls how often the ICP pings are sent to siblings that
4266 have background-ping set.
4270 MULTICAST ICP OPTIONS
4271 -----------------------------------------------------------------------------
4276 LOC: Config.mcast_group_list
4279 This tag specifies a list of multicast groups which your server
4280 should join to receive multicasted ICP queries.
4282 NOTE! Be very careful what you put here! Be sure you
4283 understand the difference between an ICP _query_ and an ICP
4284 _reply_. This option is to be set only if you want to RECEIVE
4285 multicast queries. Do NOT set this option to SEND multicast
4286 ICP (use cache_peer for that). ICP replies are always sent via
4287 unicast, so this option does not affect whether or not you will
4288 receive replies from multicast group members.
4290 You must be very careful to NOT use a multicast address which
4291 is already in use by another group of caches.
4293 If you are unsure about multicast, please read the Multicast
4294 chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
4296 Usage: mcast_groups 239.128.16.128 224.0.1.20
4298 By default, Squid doesn't listen on any multicast groups.
4301 NAME: mcast_miss_addr
4302 IFDEF: MULTICAST_MISS_STREAM
4304 LOC: Config.mcast_miss.addr
4305 DEFAULT: 255.255.255.255
4307 If you enable this option, every "cache miss" URL will
4308 be sent out on the specified multicast address.
4310 Do not enable this option unless you are are absolutely
4311 certain you understand what you are doing.
4314 NAME: mcast_miss_ttl
4315 IFDEF: MULTICAST_MISS_STREAM
4317 LOC: Config.mcast_miss.ttl
4320 This is the time-to-live value for packets multicasted
4321 when multicasting off cache miss URLs is enabled. By
4322 default this is set to 'site scope', i.e. 16.
4325 NAME: mcast_miss_port
4326 IFDEF: MULTICAST_MISS_STREAM
4328 LOC: Config.mcast_miss.port
4331 This is the port number to be used in conjunction with
4335 NAME: mcast_miss_encode_key
4336 IFDEF: MULTICAST_MISS_STREAM
4338 LOC: Config.mcast_miss.encode_key
4339 DEFAULT: XXXXXXXXXXXXXXXX
4341 The URLs that are sent in the multicast miss stream are
4342 encrypted. This is the encryption key.
4345 NAME: mcast_icp_query_timeout
4349 LOC: Config.Timeout.mcast_icp_query
4351 For multicast peers, Squid regularly sends out ICP "probes" to
4352 count how many other peers are listening on the given multicast
4353 address. This value specifies how long Squid should wait to
4354 count all the replies. The default is 2000 msec, or 2
4359 INTERNAL ICON OPTIONS
4360 -----------------------------------------------------------------------------
4363 NAME: icon_directory
4365 LOC: Config.icons.directory
4366 DEFAULT: @DEFAULT_ICON_DIR@
4368 Where the icons are stored. These are normally kept in
4372 NAME: global_internal_static
4374 LOC: Config.onoff.global_internal_static
4377 This directive controls is Squid should intercept all requests for
4378 /squid-internal-static/ no matter which host the URL is requesting
4379 (default on setting), or if nothing special should be done for
4380 such URLs (off setting). The purpose of this directive is to make
4381 icons etc work better in complex cache hierarchies where it may
4382 not always be possible for all corners in the cache mesh to reach
4383 the server generating a directory listing.
4386 NAME: short_icon_urls
4388 LOC: Config.icons.use_short_names
4391 If this is enabled Squid will use short URLs for icons.
4392 If disabled it will revert to the old behavior of including
4393 it's own name and port in the URL.
4395 If you run a complex cache hierarchy with a mix of Squid and
4396 other proxies you may need to disable this directive.
4401 -----------------------------------------------------------------------------
4404 NAME: error_directory
4406 LOC: Config.errorDirectory
4407 DEFAULT: @DEFAULT_ERROR_DIR@
4409 If you wish to create your own versions of the default
4410 (English) error files, either to customize them to suit your
4411 language or company copy the template English files to another
4412 directory and point this tag at them.
4414 The squid developers are interested in making squid available in
4415 a wide variety of languages. If you are making translations for a
4416 langauge that Squid does not currently provide please consider
4417 contributing your translation back to the project.
4422 LOC: Config.errHtmlText
4425 HTML text to include in error messages. Make this a "mailto"
4426 URL to your admin address, or maybe just a link to your
4427 organizations Web page.
4429 To include this in your error messages, you must rewrite
4430 the error template files (found in the "errors" directory).
4431 Wherever you want the 'err_html_text' line to appear,
4432 insert a %L tag in the error template file.
4435 NAME: email_err_data
4438 LOC: Config.onoff.emailErrData
4441 If enabled, information about the occurred error will be
4442 included in the mailto links of the ERR pages (if %W is set)
4443 so that the email body contains the data.
4444 Syntax is <A HREF="mailto:%w%W">%w</A>
4449 LOC: Config.denyInfoList
4452 Usage: deny_info err_page_name acl
4453 or deny_info http://... acl
4454 Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
4456 This can be used to return a ERR_ page for requests which
4457 do not pass the 'http_access' rules. Squid remembers the last
4458 acl it evaluated in http_access, and if a 'deny_info' line exists
4459 for that ACL Squid returns a corresponding error page.
4461 The acl is typically the last acl on the http_access deny line which
4462 denied access. The exceptions to this rule are:
4463 - When Squid needs to request authentication credentials. It's then
4464 the first authentication related acl encountered
4465 - When none of the http_access lines matches. It's then the last
4466 acl processed on the last http_access line.
4468 You may use ERR_ pages that come with Squid or create your own pages
4469 and put them into the configured errors/ directory.
4471 Alternatively you can specify an error URL. The browsers will
4472 get redirected (302) to the specified URL. %s in the redirection
4473 URL will be replaced by the requested URL.
4475 Alternatively you can tell Squid to reset the TCP connection
4476 by specifying TCP_RESET.
4480 OPTIONS INFLUENCING REQUEST FORWARDING
4481 -----------------------------------------------------------------------------
4484 NAME: nonhierarchical_direct
4486 LOC: Config.onoff.nonhierarchical_direct
4489 By default, Squid will send any non-hierarchical requests
4490 (matching hierarchy_stoplist or not cacheable request type) direct
4493 If you set this to off, Squid will prefer to send these
4494 requests to parents.
4496 Note that in most configurations, by turning this off you will only
4497 add latency to these request without any improvement in global hit
4500 If you are inside an firewall see never_direct instead of
4506 LOC: Config.onoff.prefer_direct
4509 Normally Squid tries to use parents for most requests. If you for some
4510 reason like it to first try going direct and only use a parent if
4511 going direct fails set this to on.
4513 By combining nonhierarchical_direct off and prefer_direct on you
4514 can set up Squid to use a parent as a backup path if going direct
4517 Note: If you want Squid to use parents for all requests see
4518 the never_direct directive. prefer_direct only modifies how Squid
4519 acts on cacheable requests.
4524 LOC: Config.accessList.AlwaysDirect
4527 Usage: always_direct allow|deny [!]aclname ...
4529 Here you can use ACL elements to specify requests which should
4530 ALWAYS be forwarded by Squid to the origin servers without using
4531 any peers. For example, to always directly forward requests for
4532 local servers ignoring any parents or siblings you may have use
4535 acl local-servers dstdomain my.domain.net
4536 always_direct allow local-servers
4538 To always forward FTP requests directly, use
4541 always_direct allow FTP
4543 NOTE: There is a similar, but opposite option named
4544 'never_direct'. You need to be aware that "always_direct deny
4545 foo" is NOT the same thing as "never_direct allow foo". You
4546 may need to use a deny rule to exclude a more-specific case of
4547 some other rule. Example:
4549 acl local-external dstdomain external.foo.net
4550 acl local-servers dstdomain .foo.net
4551 always_direct deny local-external
4552 always_direct allow local-servers
4554 NOTE: If your goal is to make the client forward the request
4555 directly to the origin server bypassing Squid then this needs
4556 to be done in the client configuration. Squid configuration
4557 can only tell Squid how Squid should fetch the object.
4559 NOTE: This directive is not related to caching. The replies
4560 is cached as usual even if you use always_direct. To not cache
4561 the replies see no_cache.
4563 This option replaces some v1.1 options such as local_domain
4569 LOC: Config.accessList.NeverDirect
4572 Usage: never_direct allow|deny [!]aclname ...
4574 never_direct is the opposite of always_direct. Please read
4575 the description for always_direct if you have not already.
4577 With 'never_direct' you can use ACL elements to specify
4578 requests which should NEVER be forwarded directly to origin
4579 servers. For example, to force the use of a proxy for all
4580 requests, except those in your local domain use something like:
4582 acl local-servers dstdomain .foo.net
4583 acl all src 0.0.0.0/0.0.0.0
4584 never_direct deny local-servers
4585 never_direct allow all
4587 or if Squid is inside a firewall and there are local intranet
4588 servers inside the firewall use something like:
4590 acl local-intranet dstdomain .foo.net
4591 acl local-external dstdomain external.foo.net
4592 always_direct deny local-external
4593 always_direct allow local-intranet
4594 never_direct allow all
4596 This option replaces some v1.1 options such as inside_firewall
4601 ADVANCED NETWORKING OPTIONS
4602 -----------------------------------------------------------------------------
4605 NAME: incoming_icp_average
4608 LOC: Config.comm_incoming.icp_average
4611 NAME: incoming_http_average
4614 LOC: Config.comm_incoming.http_average
4617 NAME: incoming_dns_average
4620 LOC: Config.comm_incoming.dns_average
4623 NAME: min_icp_poll_cnt
4626 LOC: Config.comm_incoming.icp_min_poll
4629 NAME: min_dns_poll_cnt
4632 LOC: Config.comm_incoming.dns_min_poll
4635 NAME: min_http_poll_cnt
4638 LOC: Config.comm_incoming.http_min_poll
4640 Heavy voodoo here. I can't even believe you are reading this.
4641 Are you crazy? Don't even think about adjusting these unless
4642 you understand the algorithms in comm_select.c first!
4648 LOC: Config.accept_filter
4652 The name of an accept(2) filter to install on Squid's
4653 listen socket(s). This feature is perhaps specific to
4654 FreeBSD and requires support in the kernel.
4656 The 'httpready' filter delays delivering new connections
4657 to Squid until a full HTTP request has been received.
4658 See the accf_http(9) man page for details.
4660 The 'dataready' filter delays delivering new connections
4661 to Squid until there is some data to process.
4662 See the accf_dataready(9) man page for details.
4666 The 'data' filter delays delivering of new connections
4667 to Squid until there is some data to process by TCP_ACCEPT_DEFER.
4668 You may optionally specify a number of seconds to wait by
4669 'data=N' where N is the number of seconds. Defaults to 30
4670 if not specified. See the tcp(7) man page for details.
4673 accept_filter httpready
4678 NAME: tcp_recv_bufsize
4682 LOC: Config.tcpRcvBufsz
4684 Size of receive buffer to set for TCP sockets. Probably just
4685 as easy to change your kernel's default. Set to zero to use
4686 the default buffer size.
4691 -----------------------------------------------------------------------------
4698 LOC: TheICAPConfig.onoff
4701 If you want to enable the ICAP module support, set this to on.
4704 NAME: icap_connect_timeout
4707 LOC: TheICAPConfig.connect_timeout_raw
4710 This parameter specifies how long to wait for the TCP connect to
4711 the requested ICAP server to complete before giving up and either
4712 terminating the HTTP transaction or bypassing the failure.
4714 The default for optional services is peer_connect_timeout.
4715 The default for essential services is connect_timeout.
4716 If this option is explicitly set, its value applies to all services.
4719 NAME: icap_io_timeout
4723 LOC: TheICAPConfig.io_timeout_raw
4726 This parameter specifies how long to wait for an I/O activity on
4727 an established, active ICAP connection before giving up and
4728 either terminating the HTTP transaction or bypassing the
4731 The default is read_timeout.
4734 NAME: icap_service_failure_limit
4737 LOC: TheICAPConfig.service_failure_limit
4740 The limit specifies the number of failures that Squid tolerates
4741 when establishing a new TCP connection with an ICAP service. If
4742 the number of failures exceeds the limit, the ICAP service is
4743 not used for new ICAP requests until it is time to refresh its
4744 OPTIONS. The per-service failure counter is reset to zero each
4745 time Squid fetches new service OPTIONS.
4747 A negative value disables the limit. Without the limit, an ICAP
4748 service will not be considered down due to connectivity failures
4749 between ICAP OPTIONS requests.
4752 NAME: icap_service_revival_delay
4755 LOC: TheICAPConfig.service_revival_delay
4758 The delay specifies the number of seconds to wait after an ICAP
4759 OPTIONS request failure before requesting the options again. The
4760 failed ICAP service is considered "down" until fresh OPTIONS are
4763 The actual delay cannot be smaller than the hardcoded minimum
4764 delay of 30 seconds.
4767 NAME: icap_preview_enable
4771 LOC: TheICAPConfig.preview_enable
4774 The ICAP Preview feature allows the ICAP server to handle the
4775 HTTP message by looking only at the beginning of the message body
4776 or even without receiving the body at all. In some environments,
4777 previews greatly speedup ICAP processing.
4779 During an ICAP OPTIONS transaction, the server may tell Squid what
4780 HTTP messages should be previewed and how big the preview should be.
4781 Squid will not use Preview if the server did not request one.
4783 To disable ICAP Preview for all ICAP services, regardless of
4784 individual ICAP server OPTIONS responses, set this option to "off".
4786 icap_preview_enable off
4789 NAME: icap_preview_size
4792 LOC: TheICAPConfig.preview_size
4795 The default size of preview data to be sent to the ICAP server.
4796 -1 means no preview. This value might be overwritten on a per server
4797 basis by OPTIONS requests.
4800 NAME: icap_default_options_ttl
4803 LOC: TheICAPConfig.default_options_ttl
4806 The default TTL value for ICAP OPTIONS responses that don't have
4807 an Options-TTL header.
4810 NAME: icap_persistent_connections
4814 LOC: TheICAPConfig.reuse_connections
4817 Whether or not Squid should use persistent connections to
4821 NAME: icap_send_client_ip
4825 LOC: TheICAPConfig.send_client_ip
4828 This adds the header "X-Client-IP" to ICAP requests.
4831 NAME: icap_send_client_username
4835 LOC: TheICAPConfig.send_client_username
4838 This sends authenticated HTTP client username (if available) to
4839 the ICAP service. The username value is encoded based on the
4840 icap_client_username_encode option and is sent using the header
4841 specified by the icap_client_username_header option.
4844 NAME: icap_client_username_header
4847 LOC: TheICAPConfig.client_username_header
4848 DEFAULT: X-Client-Username
4850 ICAP request header name to use for send_client_username.
4853 NAME: icap_client_username_encode
4857 LOC: TheICAPConfig.client_username_encode
4860 Whether to base64 encode the authenticated client username.
4864 TYPE: icap_service_type
4869 Defines a single ICAP service
4871 icap_service servicename vectoring_point bypass service_url
4873 vectoring_point = reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
4874 This specifies at which point of transaction processing the
4875 ICAP service should be activated. *_postcache vectoring points
4876 are not yet supported.
4878 If set to 1, the ICAP service is treated as optional. If the
4879 service cannot be reached or malfunctions, Squid will try to
4880 ignore any errors and process the message as if the service
4881 was not enabled. No all ICAP errors can be bypassed.
4882 If set to 0, the ICAP service is treated as essential and all
4883 ICAP errors will result in an error page returned to the
4885 service_url = icap://servername:port/service
4888 icap_service service_1 reqmod_precache 0 icap://icap1.mydomain.net:1344/reqmod
4889 icap_service service_2 respmod_precache 0 icap://icap2.mydomain.net:1344/respmod
4893 TYPE: icap_class_type
4898 Defines an ICAP service chain. Eventually, multiple services per
4899 vectoring point will be supported. For now, please specify a single
4902 icap_class classname servicename
4905 icap_class class_1 service_1
4906 icap class class_2 service_1
4907 icap class class_3 service_3
4911 TYPE: icap_access_type
4916 Redirects a request through an ICAP service class, depending
4919 icap_access classname allow|deny [!]aclname...
4921 The icap_access statements are processed in the order they appear in
4922 this configuration file. If an access list matches, the processing stops.
4923 For an "allow" rule, the specified class is used for the request. A "deny"
4924 rule simply stops processing without using the class. You can also use the
4925 special classname "None".
4927 For backward compatibility, it is also possible to use services
4930 icap_access class_1 allow all
4935 -----------------------------------------------------------------------------
4938 NAME: check_hostnames
4941 LOC: Config.onoff.check_hostnames
4943 For security and stability reasons Squid can check
4944 hostnames for Internet standard RFC compliance. If you want
4945 Squid to perform these checks turn this directive on.
4948 NAME: allow_underscore
4951 LOC: Config.onoff.allow_underscore
4953 Underscore characters is not strictly allowed in Internet hostnames
4954 but nevertheless used by many sites. Set this to off if you want
4955 Squid to be strict about the standard.
4956 This check is performed only when check_hostnames is set to on.
4959 NAME: cache_dns_program
4961 IFDEF: USE_DNSSERVERS
4962 DEFAULT: @DEFAULT_DNSSERVER@
4963 LOC: Config.Program.dnsserver
4965 Specify the location of the executable for dnslookup process.
4970 IFDEF: USE_DNSSERVERS
4972 LOC: Config.dnsChildren
4974 The number of processes spawn to service DNS name lookups.
4975 For heavily loaded caches on large servers, you should
4976 probably increase this value to at least 10. The maximum
4977 is 32. The default is 5.
4979 You must have at least one dnsserver process.
4982 NAME: dns_retransmit_interval
4985 LOC: Config.Timeout.idns_retransmit
4986 IFDEF: !USE_DNSSERVERS
4988 Initial retransmit interval for DNS queries. The interval is
4989 doubled each time all configured DNS servers have been tried.
4996 LOC: Config.Timeout.idns_query
4997 IFDEF: !USE_DNSSERVERS
4999 DNS Query timeout. If no response is received to a DNS query
5000 within this time all DNS servers for the queried domain
5001 are assumed to be unavailable.
5008 LOC: Config.onoff.res_defnames
5010 Normally the RES_DEFNAMES resolver option is disabled
5011 (see res_init(3)). This prevents caches in a hierarchy
5012 from interpreting single-component hostnames locally. To allow
5013 Squid to handle single-component names, enable this option.
5016 NAME: dns_nameservers
5019 LOC: Config.dns_nameservers
5021 Use this if you want to specify a list of DNS name servers
5022 (IP addresses) to use instead of those given in your
5023 /etc/resolv.conf file.
5024 On Windows platforms, if no value is specified here or in
5025 the /etc/resolv.conf file, the list of DNS name servers are
5026 taken from the Windows registry, both static and dynamic DHCP
5027 configurations are supported.
5029 Example: dns_nameservers 10.0.0.1 192.172.0.4
5034 DEFAULT: @DEFAULT_HOSTS@
5035 LOC: Config.etcHostsPath
5037 Location of the host-local IP name-address associations
5038 database. Most Operating Systems have such a file on different
5040 - Un*X & Linux: /etc/hosts
5041 - Windows NT/2000: %SystemRoot%\system32\drivers\etc\hosts
5042 (%SystemRoot% value install default is c:\winnt)
5043 - Windows XP/2003: %SystemRoot%\system32\drivers\etc\hosts
5044 (%SystemRoot% value install default is c:\windows)
5045 - Windows 9x/Me: %windir%\hosts
5046 (%windir% value is usually c:\windows)
5047 - Cygwin: /etc/hosts
5049 The file contains newline-separated definitions, in the
5050 form ip_address_in_dotted_form name [name ...] names are
5051 whitespace-separated. Lines beginning with an hash (#)
5052 character are comments.
5054 The file is checked at startup and upon configuration.
5055 If set to 'none', it won't be checked.
5056 If append_domain is used, that domain will be added to
5057 domain-local (i.e. not containing any dot character) host
5063 LOC: Config.dns_testname_list
5065 DEFAULT_IF_NONE: netscape.com internic.net nlanr.net microsoft.com
5067 The DNS tests exit as soon as the first site is successfully looked up
5069 This test can be disabled with the -D command line option.
5074 LOC: Config.appendDomain
5077 Appends local domain name to hostnames without any dots in
5078 them. append_domain must begin with a period.
5080 Be warned there are now Internet names with no dots in
5081 them using only top-domain names, so setting this may
5082 cause some Internet sites to become unavailable.
5085 append_domain .yourdomain.com
5088 NAME: ignore_unknown_nameservers
5090 LOC: Config.onoff.ignore_unknown_nameservers
5093 By default Squid checks that DNS responses are received
5094 from the same IP addresses they are sent to. If they
5095 don't match, Squid ignores the response and writes a warning
5096 message to cache.log. You can allow responses from unknown
5097 nameservers by setting this option to 'off'.
5100 NAME: dns_v4_fallback
5103 LOC: Config.onoff.dns_require_A
5105 Standard practice with DNS is to lookup either A or AAAA records
5106 and use the results if it succeeds. Only looking up the other if
5107 the first attempt fails or otherwise produces no results.
5109 That policy however will cause squid to produce error pages for some
5110 servers that advertise AAAA but are unreachable over IPv6.
5112 If this is ON squid will always lookup both AAAA and A, using both.
5113 If this is OFF squid will lookup AAAA and only try A if none found.
5115 WARNING: There are some possibly unwanted side-effects with this on:
5116 *) Doubles the load placed by squid on the DNS network.
5117 *) May negatively impact connection delay times.
5121 COMMENT: (number of entries)
5124 LOC: Config.ipcache.size
5131 LOC: Config.ipcache.low
5138 LOC: Config.ipcache.high
5140 The size, low-, and high-water marks for the IP cache.
5143 NAME: fqdncache_size
5144 COMMENT: (number of entries)
5147 LOC: Config.fqdncache.size
5149 Maximum number of FQDN cache entries.
5154 -----------------------------------------------------------------------------
5161 LOC: Config.onoff.mem_pools
5163 If set, Squid will keep pools of allocated (but unused) memory
5164 available for future use. If memory is a premium on your
5165 system and you believe your malloc library outperforms Squid
5166 routines, disable this.
5169 NAME: memory_pools_limit
5173 LOC: Config.MemPools.limit
5175 Used only with memory_pools on:
5176 memory_pools_limit 50 MB
5178 If set to a non-zero value, Squid will keep at most the specified
5179 limit of allocated (but unused) memory in memory pools. All free()
5180 requests that exceed this limit will be handled by your malloc
5181 library. Squid does not pre-allocate any memory, just safe-keeps
5182 objects that otherwise would be free()d. Thus, it is safe to set
5183 memory_pools_limit to a reasonably high value even if your
5184 configuration will use less memory.
5186 If set to zero, Squid will keep all memory it can. That is, there
5187 will be no limit on the total amount of memory used for safe-keeping.
5189 To disable memory allocation optimization, do not set
5190 memory_pools_limit to 0. Set memory_pools to "off" instead.
5192 An overhead for maintaining memory pools is not taken into account
5193 when the limit is checked. This overhead is close to four bytes per
5194 object kept. However, pools may actually _save_ memory because of
5195 reduced memory thrashing in your malloc library.
5202 LOC: opt_forwarded_for
5204 If set, Squid will include your system's IP address or name
5205 in the HTTP requests it forwards. By default it looks like
5208 X-Forwarded-For: 192.1.2.3
5210 If you disable this, it will appear as
5212 X-Forwarded-For: unknown
5215 NAME: cachemgr_passwd
5216 TYPE: cachemgrpasswd
5218 LOC: Config.passwd_list
5220 Specify passwords for cachemgr operations.
5222 Usage: cachemgr_passwd password action action ...
5224 Some valid actions are (see cache manager menu for a full list):
5263 * Indicates actions which will not be performed without a
5264 valid password, others can be performed if not listed here.
5266 To disable an action, set the password to "disable".
5267 To allow performing an action without a password, set the
5270 Use the keyword "all" to set the same password for all actions.
5273 cachemgr_passwd secret shutdown
5274 cachemgr_passwd lesssssssecret info stats/objects
5275 cachemgr_passwd disable all
5282 LOC: Config.onoff.client_db
5284 If you want to disable collecting per-client statistics,
5285 turn off client_db here.
5288 NAME: refresh_all_ims
5292 LOC: Config.onoff.refresh_all_ims
5294 When you enable this option, squid will always check
5295 the origin server for an update when a client sends an
5296 If-Modified-Since request. Many browsers use IMS
5297 requests when the user requests a reload, and this
5298 ensures those clients receive the latest version.
5300 By default (off), squid may return a Not Modified response
5301 based on the age of the cached version.
5304 NAME: reload_into_ims
5305 IFDEF: HTTP_VIOLATIONS
5309 LOC: Config.onoff.reload_into_ims
5311 When you enable this option, client no-cache or ``reload''
5312 requests will be changed to If-Modified-Since requests.
5313 Doing this VIOLATES the HTTP standard. Enabling this
5314 feature could make you liable for problems which it
5317 see also refresh_pattern for a more selective approach.
5320 NAME: maximum_single_addr_tries
5322 LOC: Config.retry.maxtries
5325 This sets the maximum number of connection attempts for a
5326 host that only has one address (for multiple-address hosts,
5327 each address is tried once).
5329 The default value is one attempt, the (not recommended)
5330 maximum is 255 tries. A warning message will be generated
5331 if it is set to a value greater than ten.
5333 Note: This is in addition to the request re-forwarding which
5334 takes place if Squid fails to get a satisfying response.
5337 NAME: retry_on_error
5339 LOC: Config.retry.onerror
5342 If set to on Squid will automatically retry requests when
5343 receiving an error response. This is mainly useful if you
5344 are in a complex cache hierarchy to work around access
5348 NAME: as_whois_server
5350 LOC: Config.as_whois_server
5351 DEFAULT: whois.ra.net
5352 DEFAULT_IF_NONE: whois.ra.net
5354 WHOIS server to query for AS numbers. NOTE: AS numbers are
5355 queried only when Squid starts up, not for every request.
5360 LOC: Config.onoff.offline
5363 Enable this option and Squid will never try to validate cached
5367 NAME: uri_whitespace
5368 TYPE: uri_whitespace
5369 LOC: Config.uri_whitespace
5372 What to do with requests that have whitespace characters in the
5375 strip: The whitespace characters are stripped out of the URL.
5376 This is the behavior recommended by RFC2396.
5377 deny: The request is denied. The user receives an "Invalid
5379 allow: The request is allowed and the URI is not changed. The
5380 whitespace characters remain in the URI. Note the
5381 whitespace is passed to redirector processes if they
5383 encode: The request is allowed and the whitespace characters are
5384 encoded according to RFC1738. This could be considered
5385 a violation of the HTTP/1.1
5386 RFC because proxies are not allowed to rewrite URI's.
5387 chop: The request is allowed and the URI is chopped at the
5388 first whitespace. This might also be considered a
5394 LOC: Config.coredump_dir
5396 DEFAULT_IF_NONE: none
5398 By default Squid leaves core files in the directory from where
5399 it was started. If you set 'coredump_dir' to a directory
5400 that exists, Squid will chdir() to that directory at startup
5401 and coredump files will be left there.
5404 # Leave coredumps in the first cache dir
5405 coredump_dir @DEFAULT_SWAP_DIR@
5411 LOC: Config.chroot_dir
5414 Use this to have Squid do a chroot() while initializing. This
5415 also causes Squid to fully drop root privileges after
5416 initializing. This means, for example, if you use a HTTP
5417 port less than 1024 and try to reconfigure, you will may get an
5418 error saying that Squid can not open the port.
5421 NAME: balance_on_multiple_ip
5423 LOC: Config.onoff.balance_on_multiple_ip
5426 Modern IP resolvers in squid sort lookup results by preferred access.
5427 By default squid will use these IP in order and only rotates to
5428 the next listed when the most preffered fails.
5430 Some load balancing servers based on round robin DNS have been
5431 found not to preserve user session state across requests
5432 to different IP addresses.
5434 Enabling this directive Squid rotates IP's per request.
5437 NAME: pipeline_prefetch
5439 LOC: Config.onoff.pipeline_prefetch
5442 To boost the performance of pipelined requests to closer
5443 match that of a non-proxied environment Squid can try to fetch
5444 up to two requests in parallel from a pipeline.
5446 Defaults to off for bandwidth management and access logging
5450 NAME: high_response_time_warning
5453 LOC: Config.warnings.high_rptm
5456 If the one-minute median response time exceeds this value,
5457 Squid prints a WARNING with debug level 0 to get the
5458 administrators attention. The value is in milliseconds.
5461 NAME: high_page_fault_warning
5463 LOC: Config.warnings.high_pf
5466 If the one-minute average page fault rate exceeds this
5467 value, Squid prints a WARNING with debug level 0 to get
5468 the administrators attention. The value is in page faults
5472 NAME: high_memory_warning
5474 LOC: Config.warnings.high_memory
5477 If the memory usage (as determined by mallinfo) exceeds
5478 this amount, Squid prints a WARNING with debug level 0 to get
5479 the administrators attention.
5482 NAME: sleep_after_fork
5483 COMMENT: (microseconds)
5485 LOC: Config.sleep_after_fork
5488 When this is set to a non-zero value, the main Squid process
5489 sleeps the specified number of microseconds after a fork()
5490 system call. This sleep may help the situation where your
5491 system reports fork() failures due to lack of (virtual)
5492 memory. Note, however, if you have a lot of child
5493 processes, these sleep delays will add up and your
5494 Squid will not service requests for some amount of time
5495 until all the child processes have been started.
5496 On Windows value less then 1000 (1 milliseconds) are