1squid(8) System Manager's Manual squid(8)
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6 squid - HTTP web proxy caching server
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9 squid [-dhisrvzCFNRSVYX] [--foreground] [-l facility ] [-f config-file
10 ] [-[au] port ] [-k signal ] [-n service-name ] [-O command-line ]
11
13 squid is a high-performance proxy caching server for web clients, sup‐
14 porting FTP, ICAP, ICP, HTCP and HTTP data objects. Unlike traditional
15 caching software, Squid handles all requests in a single, non-blocking
16 process.
17 Squid keeps meta data and especially hot objects cached in RAM, caches
19 DNS lookups, supports non-blocking DNS lookups, and implements negative
20 caching of failed requests.
21 Squid supports SSL, extensive access controls, and full request log‐
23 ging. By using the lightweight Internet Cache Protocols ICP, HTCP or
24 CARP, Squid caches can be arranged in a hierarchy or mesh for addi‐
25 tional bandwidth savings.
26 Squid consists of a main server program squid , some optional programs
28 for custom processing and authentication, and some management and
29 client tools. When squid starts up, it spawns a configurable number of
30 helper processes, each of which can perform parallel lookups. This re‐
31 duces the amount of time the cache waits for results.
32 Squid is derived from the ARPA-funded Harvest Project.
34 This manual page only lists the command line arguments. For details on
36 how to configure Squid see the file
37 /usr/share/doc/squid/squid.conf.documented, the Squid wiki FAQ and ex‐
38 amples at https://wiki.squid-cache.org/ , or the configuration manual
39 on the Squid home page http://www.squid-cache.org/Doc/config/
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42 -a port Specify HTTP port number where Squid should listen for re‐
43 quests, in addition to any http_port specifications in
44 squid.conf
45 -C Do not catch fatal signals.
47 -d level Write debugging to stderr also.
49 -f file Use the given config-file instead of /etc/squid/squid.conf
51 . If the file name starts with a ! or | then it is as‐
52 sumed to be an external command or command line. Can for
53 example be used to pre-process the configuration before it
54 is being read by Squid. To facilitate this Squid also un‐
55 derstands the common #line notion to indicate the real
56 source file.
57 -F Don't serve any requests until store is rebuilt.
59 -h Print help message.
61 -i Install as a Windows Service (see -n option).
63 -k reconfigure | rotate | shutdown | interrupt | kill | debug | check |
65 parse
66 Parse configuration file, then send signal to running copy
67 (except -k parse ) and exit.
68 -l facility Use specified syslog facility. Implies -s
70 -n name Specify Windows Service name to use for service operations,
72 default is: Squid
73 -N No daemon mode.
75 --foreground
77 Parent process does not exit until its children have fin‐
78 ished. It has no effect with -N which does not fork/exit at
79 startup.
80 --kid roleID
82 Play a given SMP kid process role, with a given ID. Do not
83 use this option. It is meant for the master process use
84 only.
85 -O options Set Windows Service Command line options in Registry.
87 -r Remove a Windows Service (see -n option).
89 -R Do not set REUSEADDR on port.
91 -s Enable logging to syslog. Also configurable in
93 /etc/squid/squid.conf
94 -S Double-check swap during rebuild.
96 -u port Specify ICP port number (default: 3130), disable with 0.
98 -v Print version and build details.
100 -X Force full debugging.
102 -Y Only return UDP_HIT or UDP_MISS_NOFETCH during fast reload.
104 -z Create missing swap directories and other missing cache_dir
106 structures, then exit. All cache_dir types create the con‐
107 figured top-level directory if it is missing. Other actions
108 are type-specific. For example, ufs-based storage systems
109 create missing L1 and L2 directories while Rock creates the
110 missing database file.
111 This option does not enable validation of any present swap
113 structures. Its focus is on creation of missing pieces. If
114 nothing is missing, squid -z just exits. If you suspect
115 cache_dir corruption, you must delete the top-level
116 cache_dir directory before running squid -z.
117 By default, squid -z runs in daemon mode (so that configu‐
119 ration macros and other SMP features work as expected), re‐
120 turning control to the caller before cache_dirs are fully
121 initialized. If run from init scripts or daemon managers,
122 the caller often needs to wait for the initialization to
123 complete before proceeding further. Use --foreground op‐
124 tion to prevent premature exits. To disable daemon mode,
125 use -N option.
126
128 Squid configuration files located in /etc/squid/:
129 squid.conf
131 The main configuration file. You must initially make changes to
132 this file for squid to work. For example, the default configura‐
133 tion only allows access from RFC private LAN networks. Some
134 packaging distributions block even that.
135 squid.conf.default
137 Reference copy of the configuration file. Always kept up to date
138 with the version of Squid you are using.
139 Use this to look up the default configuration settings and syn‐
141 tax after upgrading.
142 squid.conf.documented
144 Reference copy of the configuration file. Always kept up to date
145 with the version of Squid you are using.
146 Use this to read the documentation for configuration options
148 available in your build of Squid. The online configuration man‐
149 ual is also available for a full reference of options. see‐
150 http://www.squid-cache.org/Doc/config/
151 cachemgr.conf
153 The main configuration file for the web cachemgr.cgi tools.
154 msntauth.conf
156 The main configuration file for the Sample MSNT authenticator.
157 errorpage.css
159 CSS Stylesheet to control the display of generated error pages.
160 Use this to set any company branding you need, it will apply to
161 every language Squid provides error pages for.
162 Some files also located elsewhere:
164 /etc/squid/mime.conf (mime_table)
166 MIME type mappings for FTP gatewaying
167 /usr/share/squid/errors
169 Location of Squid error pages and templates.
170
172 Squid was written over many years by a changing team of developers and
173 maintained in turn by Duane Wessels <duane@squid-cache.org> Henrik
174 Nordstrom <hno@squid-cache.org> Amos Jeffries <amosjeffries@squid-
175 cache.org>
176 With contributions from many others in the Squid community. see CON‐
178 TRIBUTORS for a full list of individuals who contributed code. see
179 CREDITS for a list of major code contributing copyright holders.
180
182 * Copyright (C) 1996-2023 The Squid Software Foundation and contribu‐
183 tors
184 *
185 * Squid software is distributed under GPLv2+ license and includes
186 * contributions from numerous individuals and organizations.
187 * Please see the COPYING and CONTRIBUTORS files for details.
188
190 Questions on the usage of this program can be sent to the Squid Users
191 mailing list <squid-users@lists.squid-cache.org>
192
194 Bug reports need to be made in English. See https://wiki.squid-
195 cache.org/SquidFaq/BugReporting for details of what you need to include
196 with your bug report.
197 Report bugs or bug fixes using https://bugs.squid-cache.org/
199 Report serious security bugs to Squid Bugs <squid-bugs@lists.squid-
201 cache.org>
202 Report ideas for new improvements to the Squid Developers mailing list
204 <squid-dev@lists.squid-cache.org>
205
207 cachemgr.cgi (8), squidclient (1), basic_pam_auth (8), basic_ldap_auth
208 [1m(8), ext_ldap_group_acl (8), ext_session_acl (8), ext_unix_group_acl
209 [1m(8),
210 The Squid FAQ wiki https://wiki.squid-cache.org/SquidFaq
211 The Squid Configuration Manual http://www.squid-cache.org/Doc/config/
212 squid(8)