Chapter 21. Apache HTTP Server

Chapter 21. Apache HTTP Server

21.1. Apache HTTP Server 2.2
21.2. Migrating Apache HTTP Server Configuration Files
21.3. Starting and Stopping httpd
21.4. Apache HTTP Server Configuration
21.5. Configuration Directives in httpd.conf
21.6. Adding Modules
21.7. Virtual Hosts
21.8. Apache HTTP Secure Server Configuration
21.9. Additional Resources

The Apache HTTP Server is a robust, commercial-grade open source Web server developed by the Apache Software Foundation ( Red Hat Enterprise Linux includes the Apache HTTP Server 2.2 as well as a number of server modules designed to enhance its functionality.

The default configuration file installed with the Apache HTTP Server works without alteration for most situations. This chapter outlines many of the directives found within its configuration file (/etc/httpd/conf/httpd.conf) to aid those who require a custom configuration or need to convert a configuration file from the older Apache HTTP Server 1.3 format.


If using the graphical HTTP Configuration Tool (system-config-httpd ), do not hand edit the Apache HTTP Server's configuration file as the HTTP Configuration Tool regenerates this file whenever it is used.

21.1. Apache HTTP Server 2.2

There are important differences between the Apache HTTP Server 2.2 and version 2.0 (version 2.0 shipped with Red Hat Enterprise Linux 4 and earlier). This section reviews some of the features of Apache HTTP Server 2.2 and outlines important changes. If you are upgrading from version 1.3, you should also read the instructions on migrating from version 1.3 to version 2.0. For instructions on migrating a version 1.3 configuration file to the 2.0 format, refer to Section 21.2.2, “Migrating Apache HTTP Server 1.3 Configuration Files to 2.0”.

21.1.1. Features of Apache HTTP Server 2.2

Apache HTTP Server 2.2 features the following improvements over version 2.0 :

  • Improved caching modules (mod_cache, mod_disk_cache, mod_mem_cache).

  • A new structure for authentication and authorization support, replacing the authentication modules provided in previous versions.

  • Support for proxy load balancing (mod_proxy_balancer)

  • support for handling large files (namely, greater than 2GB) on 32-bit platforms

The following changes have been made to the default httpd configuration:

  • The mod_cern_meta and mod_asis modules are no longer loaded by default.

  • The mod_ext_filter module is now loaded by default.

If upgrading from a previous release of Red Hat Enterprise Linux, the httpd configuration will need to be updated for httpd 2.2. For more information, refer to