When Apache starts, it connects to some port and address on the local machine and waits for incoming requests. By default, it listens to all addresses on the machine, and to the port as specified by the Port directive in the server configuration. ... There are two directives used to restrict or specify which addresses and ports Apache listens to. ... Listen can be used to make a single Apache server listen to more than one address and/or port. ... Syntax: Listen [ port | IP-address:port ] . ...