Apache Reference: http_core, ServerName

ServerName

Canonical Server Host Name
Syntax: ServerName A
Example: ServerName www.foo.dom
Since: Apache 1.0

This directive sets the canonical host name of the server. It is used mainly to create redirection URLs. If the host name is not specified, then the server attempts to deduce it from its own IP address; this process may not work reliably or may not return the preferred host name, however.