1 <?xml version='1.0' encoding='UTF-8' ?>
2 <!DOCTYPE manualpage SYSTEM "./style/manualpage.dtd">
3 <?xml-stylesheet type="text/xsl" href="./style/manual.en.xsl"?>
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7 Licensed to the Apache Software Foundation (ASF) under one or more
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10 The ASF licenses this file to You under the Apache License, Version 2.0
11 (the "License"); you may not use this file except in compliance with
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18 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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23 <manualpage metafile="configuring.xml.meta">
25 <title>Configuration Files</title>
28 <p>This document describes the files used to configure the Apache HTTP server (httpd).</p>
32 <title>Main Configuration Files</title>
35 <module>mod_mime</module>
38 <directive module="core" type="section">IfDefine</directive>
39 <directive module="core">Include</directive>
40 <directive module="mod_mime">TypesConfig</directive>
44 <p>The Apache HTTP Server is configured by placing <a
45 href="mod/directives.html">directives</a> in plain text
46 configuration files. The main configuration file is usually called
47 <code>httpd.conf</code>. The location of this file is set at
48 compile-time, but may be overridden with the <code>-f</code>
49 command line flag. In addition, other configuration files may be
50 added using the <directive module="core">Include</directive>
51 directive, and wildcards can be used to include many configuration
52 files. Any directive may be placed in any of these configuration
53 files. Changes to the main configuration files are only
54 recognized by httpd when it is started or restarted.</p>
56 <p>The server also reads a file containing mime document types;
57 the filename is set by the <directive
58 module="mod_mime">TypesConfig</directive> directive,
59 and is <code>mime.types</code> by default.</p>
63 <title>Syntax of the Configuration Files</title>
65 <p>httpd configuration files contain one directive per line.
66 The back-slash "\" may be used as the last character on a line
67 to indicate that the directive continues onto the next line.
68 There must be no other characters or white space between the
69 back-slash and the end of the line.</p>
71 <p>Directives in the configuration files are case-insensitive,
72 but arguments to directives are often case sensitive. Lines
73 that begin with the hash character "#" are considered
74 comments, and are ignored. Comments may <strong>not</strong> be
75 included on a line after a configuration directive. Blank lines
76 and white space occurring before a directive are ignored, so
77 you may indent directives for clarity.</p>
79 <p>The values of shell environment variables can be used in
80 configuration file lines using the syntax <code>${ENVVAR}</code>.
81 If "ENVVAR" is the name of a valid environment variable, the value
82 of that variable is substituted into that spot in the
83 configuration file line, and processing continues as if that text
84 were found directly in the configuration file. (If the ENVVAR
85 variable is not found, the characters "${ENVVAR}" are left
86 unchanged for use by later stages in the config file
89 <p>Only environment variables defined before the server is started
90 can be used in expansions. Variables defined in the
91 configuration file itself, for example with <directive
92 module="mod_env">SetEnv</directive>, take effect too late to be
93 used for expansions in the configuration file.</p>
95 <p>The maximum length of a line in the configuration file, after
96 environment-variable substitution, joining any continued lines and
97 removing leading and trailing white space, is 8192 characters.</p>
99 <p>You can check your configuration files for syntax errors
100 without starting the server by using <code>apachectl
101 configtest</code> or the <code>-t</code> command line
105 <section id="modules">
106 <title>Modules</title>
110 <module>mod_so</module>
113 <directive module="core" type="section">IfModule</directive>
114 <directive module="mod_so">LoadModule</directive>
118 <p>httpd is a modular server. This implies that only the most
119 basic functionality is included in the core server. Extended
120 features are available through <a
121 href="mod/">modules</a> which can be loaded
122 into httpd. By default, a <a
123 href="mod/module-dict.html#Status">base</a> set of modules is
124 included in the server at compile-time. If the server is
125 compiled to use <a href="dso.html">dynamically loaded</a>
126 modules, then modules can be compiled separately and added at
127 any time using the <directive module="mod_so">LoadModule</directive>
129 Otherwise, httpd must be recompiled to add or remove modules.
130 Configuration directives may be included conditional on a
131 presence of a particular module by enclosing them in an <directive
132 module="core" type="section">IfModule</directive> block.</p>
134 <p>To see which modules are currently compiled into the server,
135 you can use the <code>-l</code> command line option.</p>
139 <title>Scope of Directives</title>
143 <directive module="core" type="section">Directory</directive>
144 <directive module="core" type="section">DirectoryMatch</directive>
145 <directive module="core" type="section">Files</directive>
146 <directive module="core" type="section">FilesMatch</directive>
147 <directive module="core" type="section">Location</directive>
148 <directive module="core" type="section">LocationMatch</directive>
149 <directive module="core" type="section">VirtualHost</directive>
153 <p>Directives placed in the main configuration files apply to
154 the entire server. If you wish to change the configuration for
155 only a part of the server, you can scope your directives by
156 placing them in <directive module="core"
157 type="section">Directory</directive>, <directive module="core"
158 type="section">DirectoryMatch</directive>, <directive module="core"
159 type="section">Files</directive>, <directive module="core"
160 type="section">FilesMatch</directive>, <directive module="core"
161 type="section">Location</directive>, and <directive module="core"
162 type="section">LocationMatch</directive>
163 sections. These sections limit the application of the
164 directives which they enclose to particular filesystem
165 locations or URLs. They can also be nested, allowing for very
166 fine grained configuration.</p>
168 <p>httpd has the capability to serve many different websites
169 simultaneously. This is called <a href="vhosts/">Virtual
170 Hosting</a>. Directives can also be scoped by placing them
171 inside <directive module="core" type="section">VirtualHost</directive>
172 sections, so that they will only apply to requests for a
173 particular website.</p>
175 <p>Although most directives can be placed in any of these
176 sections, some directives do not make sense in some contexts.
177 For example, directives controlling process creation can only
178 be placed in the main server context. To find which directives
179 can be placed in which sections, check the <a
180 href="mod/directive-dict.html#Context">Context</a> of the
181 directive. For further information, we provide details on <a
182 href="sections.html">How Directory, Location and Files sections
186 <section id="htaccess">
187 <title>.htaccess Files</title>
191 <directive module="core">AccessFileName</directive>
192 <directive module="core">AllowOverride</directive>
196 <p>httpd allows for decentralized management of configuration
197 via special files placed inside the web tree. The special files
198 are usually called <code>.htaccess</code>, but any name can be
199 specified in the <directive module="core">AccessFileName</directive>
200 directive. Directives placed in <code>.htaccess</code> files
201 apply to the directory where you place the file, and all
202 sub-directories. The <code>.htaccess</code> files follow the
203 same syntax as the main configuration files. Since
204 <code>.htaccess</code> files are read on every request, changes
205 made in these files take immediate effect.</p>
207 <p>To find which directives can be placed in
208 <code>.htaccess</code> files, check the <a
209 href="mod/directive-dict.html#Context">Context</a> of the
210 directive. The server administrator further controls what
211 directives may be placed in <code>.htaccess</code> files by
212 configuring the <directive module="core">AllowOverride</directive>
213 directive in the main configuration files.</p>
215 <p>For more information on <code>.htaccess</code> files, see
216 the <a href="howto/htaccess.html">.htaccess tutorial</a>.</p>