Configuration Files

Main Configuration Files

Related Modules	Related Directives
mod_mime	<IfDefine> Include TypesConfig

Apache HTTP Server is configured by placing directives in plain text configuration files. The main configuration file is usually called httpd.conf. The location of this file is set at compile-time, but may be overridden with the -f command line flag. In addition, other configuration files may be added using the Include 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.

The server also reads a file containing mime document types; the filename is set by the TypesConfig directive, and is mime.types by default.

Syntax of the Configuration Files

httpd configuration files contain one directive per line. The backslash "\" 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 backslash and the end of the line.

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 the same line as a configuration directive. White space occurring before a directive is ignored, so you may indent directives for clarity. Blank lines are also ignored.

The values of variables defined with the Define of or shell environment variables can be used in configuration file lines using the syntax ${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 Define take precedence over shell environment variables. If the "VAR" variable is not found, the characters ${VAR} are left unchanged, and a warning is logged. Variable names may not contain colon ":" characters, to avoid clashes with RewriteMap's syntax.

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

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 apachectl configtest or the -t command line option.

You can use mod_info's -DDUMP_CONFIG to dump the configuration with all included files and environment variables resolved and all comments and non-matching <IfDefine> and <IfModule> sections removed. However, the output does not reflect the merging or overriding that may happen for repeated directives.

Modules

Related Modules	Related Directives
mod_so	<IfModule> LoadModule

httpd is a modular server. This implies that only the most basic functionality is included in the core server. Extended features are available through