mod_rewrite is a module for Apache. This module is used for internal rewrites (external requests that should load a different resource) and external redirects (external requests that should make the client request a different url).
mod_rewrite provides a finer control over internal rewrites than mod_alias, as the latter can only map requests to filenames. mod_rewrite provides some means of access control, but this is usually better done with mod_authz_core and mod_authz_host. mod_rewrite provides some integration with mod_proxy, but for performance reasons this integration should not be used and instead
ProxyPassMatch of the latter module should be used.
mod_rewrite can be set up in a way that allows for directives to be placed in the dynamic (.htaccess) configuration files. For performance reasons, one should always use the static (httpd.conf) configuration file whenever possible.
mod_rewrite must be enabled before being used on an Apache server.
Then restart Apache with
service apache2 restart
Add or uncomment the following line in the static configuration file (such as
LoadModule rewrite_module modules/mod_rewrite.so
Then restart Apache.
Using mod_rewrite in the static configuration file
Add the following directive before using any other mod_rewrite directive (RewriteRule, RewriteCond, RewriteBase or RewriteMap).
By default the engine is turned off. mod_rewrite directives found while the engine is turned off are ignored. Enable it from within the virtual host context when using virtual hosts, or from specific directory contexts when applicable.
Using mod_rewrite from the dynamic configuration files
Important: Using the dynamic configuration files (.htaccess) is a big performance hit. When you have access to the static configuration file (httpd.conf or something similar) you should use that instead.
In the static configuration file, allow dynamic configuration files to override “Fileinfo” using
AllowOverride. This directive must be placed in directory context:
The filename used for dynamic configuration files is governed by the
AccessFileName directive. By default, the dynamic configuration files are hidden files called
At the top of each dynamic configuration file containing mod_rewrite directives, add the following directive: