- How to Enable / Disable Modules into Apache on Linux

Apache 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 Apache. 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 LoadModule directive.

The module are available in the /etc/apache2/mods-available directory. You can use the a2enmod command to enable a module. You can use the a2dismod command to disable a module. Once you enable the module, the module will be available in the the /etc/apache2/mods-enabled directory.

Example:
To enable ssl module, use following command:

sudo a2enmod ssl

To enable suexec module, use following command:

sudo a2enmod suexec

When you’re finished enabling the modules that you want, you’ll need to perform a “force-reload” of Apache using following command: sudo service apache2 restart

Note: Above commands (a2enmod  and a2dismod) will work with any Linux distribution and not only limited to Ubuntu.

source:http://linuxpoison.blogspot.com/2010/07/135781677513931.html