Red Hat ENTERPRISE LINUX 5 - DEPLOYMENT Deployment Manual page 363

This directive has been deprecated for the configuration of virtual hosts.
By default, Group is set to apache.
HeaderName
HeaderName names the file which, if it exists in the directory, is prepended to the start of server
generated directory listings. Like ReadmeName, the server tries to include it as an HTML document if
possible or in plain text if not.
HostnameLookups
HostnameLookups can be set to on, off, or double. If HostnameLookups is set to on, the
server automatically resolves the IP address for each connection. Resolving the IP address means
that the server makes one or more connections to a DNS server, adding processing overhead. If
HostnameLookups is set to double, the server performs a double-reverse DNS look up adding even
more processing overhead.
To conserve resources on the server, HostnameLookups is set to off by default.
If hostnames are required in server log files, consider running one of the many log analyzer tools that
perform the DNS lookups more efficiently and in bulk when rotating the Web server log files.
IfDefine
The IfDefine tags surround configuration directives that are applied if the "test" stated in the
IfDefine tag is true. The directives are ignored if the test is false.
The test in the IfDefine tags is a parameter name (for example, HAVE_PERL). If the parameter is
defined, meaning that it is provided as an argument to the server's start-up command, then the test is
true. In this case, when the Web server is started, the test is true and the directives contained in the
IfDefine tags are applied.
IfModule
<IfModule> and </IfModule> tags create a conditional container which are only activated if the
specified module is loaded. Directives within the IfModule container are processed under one of two
conditions. The directives are processed if the module contained within the starting <IfModule> tag
is loaded. Or, if an exclamation point ! appears before the module name, the directives are processed
only if the module specified in the <IfModule> tag is not loaded.
For more information about Apache HTTP Server modules, refer to
Include
Include allows other configuration files to be included at runtime.
The path to these configuration files can be absolute or relative to the ServerRoot.
Important
For the server to use individually packaged modules, such as mod_ssl, mod_perl, and
php, the following directive must be included in Section 1: Global Environment of
httpd.conf:
General Configuration Tips
Section 22.6, "Adding Modules".
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