server).</p>
<p>If no <directive>ServerName</directive> is specified, then the
- server attempts to deduce the hostname by performing a reverse
- lookup on the IP address. If no port is specified in the
+ server attempts to deduce the client visible hostname by performing a
+ reverse lookup on an IP address of the systems hostname.</p>
+
+ <p>If no port is specified in the
<directive>ServerName</directive>, then the server will use the
port from the incoming request. For optimal reliability and
predictability, you should specify an explicit hostname and port
module="core">ServerAlias</directive> directives to the server name
present in the request.</p>
+ <p>If you omit the <directive module="core">ServerName</directive>
+ directive from any name-based virtual host, the server will default
+ to a fully qualified domain name (FQDN) derived from the system hostname.
+ This implicitly set server name can lead to counter-intuitive virtual host
+ matching and is discouraged.</p>
+
<section id="defaultvhost"><title>The default name-based vhost for an IP and port combination </title>
<p> If no matching ServerName or ServerAlias is found in the set of
virtual hosts containing the most specific matching IP address and port