The Apache core does relatively little; Apache gains its functionality from modules. Each module solves a well-defined problem by adding necessary features. By adding or removing modules to supply the functionality you want Apache to have, you can tailor Apache server to suit your exact needs.
Nearly 70 core modules are included with the basic Apache server. Many more are available from other developers. The Apache Module Registry is a repository for add-on modules for Apache; you can find it at http://modules.apache.org/. The modules are stored in the
Each module adds new directives that you can use in your configuration files. As you might guess, there are far too many extra commands, switches, ...