Discovering Apache

This chapter provides a quick introduction to the Apache web server, its architecture, and the differences between major versions (1.3, 2.x). It explains how to download and compile Apac he from source or using binary packages, how to enable or disable common modules, the layout of server files, and the structure and syntax of the server configuration files. It also covers how to start/stop/restart Apache and the minimum configuration changes required to get Apache up and running.

Apache is the most popular web server on the Internet, with around 68% of the market share, according to Netcraft (http://www.netcraft.com).

Apache is

• Portable It runs on Linux, Windows, Mac OS X, and many other operating systems.

• Flexible It has a modular, extensible architecture and can be configured in a variety of ways.

• Open Source You can download and use Apache for free. Availability of the source code means you can create custom builds of Apache.

There are two main versions of Apache in widespread use today: the 1.3 series and the 2.x series.

Apache 2.0 includes a number of improvements and features over Apache 1.3; however, it is incompatible with all modules written for Apache 1.3. As a basic rule of thumb, use Apache 2.x if you

• Are running a Windows operating system.

• Need to serve a lot of static content that can benefit from a threaded processing module on Unix.

• Need one of the new features only available in Apache 2.0.

• Are completely new to Apache.

Run Apache 1.3 if you

• Need to run in-house or third-party modules that have not yet been ported to Apache 2.x.

• Need to run software such as PHP with nonthread-safe extensions (though the same code will probably run equally well on Apache 2.0 with the prefork MPM).

• Are already familiar with Apache 1.3 and have no specific need to upgrade.