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<title>Configuration Files</title>

<summary>

<p>This document describes the files used to configure the Apache HTTP server (httpd).</p>

</summary>

<section id="main">

<title>Main Configuration Files</title>

<related>

<modulelist>

<module>mod_mime</module>

</modulelist>

<directivelist>

<directive module="core" type="section">IfDefine</directive>

<directive module="core">Include</directive>

<directive module="mod_mime">TypesConfig</directive>

</directivelist>

</related>

<p>The Apache HTTP Server is configured by placing <a

href="mod/directives.html">directives</a> in plain text

configuration files. The main configuration file is usually called

<code>httpd.conf</code>. The location of this file is set at

compile-time, but may be overridden with the <code>-f</code>

command line flag. In addition, other configuration files may be

added using the <directive module="core">Include</directive>

directive, and wildcards can be used to include many configuration

files. Any directive may be placed in any of these configuration

files. Changes to the main configuration files are only

recognized by httpd when it is started or restarted.</p>

<p>The server also reads a file containing mime document types;

the filename is set by the <directive

module="mod_mime">TypesConfig</directive> directive,

and is <code>mime.types</code> by default.</p>

</section>

<section id="syntax">

<title>Syntax of the Configuration Files</title>

<p>httpd configuration files contain one directive per line.

The back-slash "\" may be used as the last character on a line

to indicate that the directive continues onto the next line.

There must be no other characters or white space between the

back-slash and the end of the line.</p>

<p>Directives in the configuration files are case-insensitive,

but arguments to directives are often case sensitive. Lines

that begin with the hash character "#" are considered

comments, and are ignored. Comments may <strong>not</strong> be

included on a line after a configuration directive. Blank lines

and white space occurring before a directive are ignored, so

you may indent directives for clarity.</p>

<p>The values of shell environment variables can be used in

configuration file lines using the syntax <code>${ENVVAR}</code>.

If "ENVVAR" is the name of a valid environment variable, the value

of that variable is substituted into that spot in the

configuration file line, and processing continues as if that text

were found directly in the configuration file. (If the ENVVAR

variable is not found, the characters "${ENVVAR}" are left

unchanged for use by later stages in the config file

processing.)</p>

<p>Only environment variables defined before the server is started

can be used in expansions. Variables defined in the

configuration file itself, for example with <directive

module="mod_env">SetEnv</directive>, take effect too late to be

used for expansions in the configuration file.</p>

<p>The maximum length of a line in the configuration file, after

environment-variable substitution, joining any continued lines and

removing leading and trailing white space, is 8192 characters.</p>

<p>You can check your configuration files for syntax errors

without starting the server by using <code>apachectl

configtest</code> or the <code>-t</code> command line

option.</p>

</section>

<section id="modules">

<title>Modules</title>

<related>

<modulelist>

<module>mod_so</module>

</modulelist>

<directivelist>

<directive module="core" type="section">IfModule</directive>

<directive module="mod_so">LoadModule</directive>

</directivelist>

</related>

<p>httpd is a modular server. This implies that only the most

basic functionality is included in the core server. Extended

features are available through <a

href="mod/">modules</a> which can be loaded

into httpd. By default, a <a

href="mod/module-dict.html#Status">base</a> set of modules is

included in the server at compile-time. If the server is

compiled to use <a href="dso.html">dynamically loaded</a>

modules, then modules can be compiled separately and added at

any time using the <directive module="mod_so">LoadModule</directive>

directive.

Otherwise, httpd must be recompiled to add or remove modules.

Configuration directives may be included conditional on a

presence of a particular module by enclosing them in an <directive

module="core" type="section">IfModule</directive> block.</p>

<p>To see which modules are currently compiled into the server,

you can use the <code>-l</code> command line option.</p>

</section>

<section id="scope">

<title>Scope of Directives</title>

<related>

<directivelist>

<directive module="core" type="section">Directory</directive>

<directive module="core" type="section">DirectoryMatch</directive>

<directive module="core" type="section">Files</directive>

<directive module="core" type="section">FilesMatch</directive>

<directive module="core" type="section">Location</directive>

<directive module="core" type="section">LocationMatch</directive>

<directive module="core" type="section">VirtualHost</directive>

</directivelist>

</related>

<p>Directives placed in the main configuration files apply to

the entire server. If you wish to change the configuration for

only a part of the server, you can scope your directives by

placing them in <directive module="core"

type="section">Directory</directive>, <directive module="core"

type="section">DirectoryMatch</directive>, <directive module="core"

type="section">Files</directive>, <directive module="core"

type="section">FilesMatch</directive>, <directive module="core"

type="section">Location</directive>, and <directive module="core"

type="section">LocationMatch</directive>

sections. These sections limit the application of the

directives which they enclose to particular filesystem

locations or URLs. They can also be nested, allowing for very

fine grained configuration.</p>

<p>httpd has the capability to serve many different websites

simultaneously. This is called <a href="vhosts/">Virtual

Hosting</a>. Directives can also be scoped by placing them

inside <directive module="core" type="section">VirtualHost</directive>

sections, so that they will only apply to requests for a

particular website.</p>

<p>Although most directives can be placed in any of these

sections, some directives do not make sense in some contexts.

For example, directives controlling process creation can only

be placed in the main server context. To find which directives

can be placed in which sections, check the <a

href="mod/directive-dict.html#Context">Context</a> of the

directive. For further information, we provide details on <a

href="sections.html">How Directory, Location and Files sections

work</a>.</p>

</section>

<section id="htaccess">

<title>.htaccess Files</title>

<related>

<directivelist>

<directive module="core">AccessFileName</directive>

<directive module="core">AllowOverride</directive>

</directivelist>

</related>

<p>httpd allows for decentralized management of configuration

via special files placed inside the web tree. The special files

are usually called <code>.htaccess</code>, but any name can be

specified in the <directive module="core">AccessFileName</directive>

directive. Directives placed in <code>.htaccess</code> files

apply to the directory where you place the file, and all

sub-directories. The <code>.htaccess</code> files follow the

same syntax as the main configuration files. Since

<code>.htaccess</code> files are read on every request, changes

made in these files take immediate effect.</p>

<p>To find which directives can be placed in

<code>.htaccess</code> files, check the <a

href="mod/directive-dict.html#Context">Context</a> of the

directive. The server administrator further controls what

directives may be placed in <code>.htaccess</code> files by

configuring the <directive module="core">AllowOverride</directive>

directive in the main configuration files.</p>

<p>For more information on <code>.htaccess</code> files, see

the <a href="howto/htaccess.html">.htaccess tutorial</a>.</p>

</section>

</manualpage>