Configuration Files

This document describes the files used to configure Apache HTTP Server.

| Related Modules | Related Directives | |---|---|

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

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.Include

The server also reads a file containing mime document types; the filename is set by the

Arguments to directives are separated by whitespace. If an argument contains spaces, you must enclose that argument in quotes.

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 not 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.

The values of variables defined with the

of or shell environment variables can be used in configuration file lines using the syntax Define${VAR}

. If "VAR" is the name of a valid 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. Variables defined with

take precedence over shell environment variables. If the "VAR" variable is not found, the characters Define${VAR}

are left unchanged, and a warning is logged. Variable names may not contain colon ":" characters, to avoid clashes with

Only shell environment variables defined before the server is started can be used in expansions. Environment variables defined in the configuration file itself, for example with

, take effect too late to be used for expansions in the configuration file.SetEnv

The maximum length of a line in normal configuration files, after variable substitution and joining any continued lines, is approximately 16 MiB. In .htaccess files, the maximum length is 8190 characters.

You can check your configuration files for syntax errors without starting the server by using apache2ctl configtest

to dump the configuration with all included files and environment variables resolved and all comments and non-matching

sections removed. However, the output does not reflect the merging or overriding that may happen for repeated directives.

httpd is a modular server. This implies that only the most basic functionality is included in the core server. Extended features are available through modules which can be loaded into httpd. By default, a base set of modules is included in the server at compile-time. If the server is compiled to use dynamically loaded modules, then modules can be compiled separately and added at any time using the

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 LoadModule

blocks are not required, and in some cases may mask the fact that you're missing an important module.

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.

httpd has the capability to serve many different websites simultaneously. This is called Virtual Hosting. Directives can also be scoped by placing them inside

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

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 Context of the directive. For further information, we provide details on How Directory, Location and Files sections work.

files follow the same syntax as the main configuration files. Since .htaccess

files are read on every request, changes made in these files take immediate effect.

files, check the Context of the directive. The server administrator further controls what directives may be placed in .htaccess

files, see the .htaccess tutorial.

Modules | Directives | FAQ | Glossary | Sitemap

Apache HTTP Server Version 2.4