(Wide Area Network port) The socket on a network device that is wired to an external network such as the Internet. In the home and small business, a WAN port is typically an Ethernet port on a router that is wired to its counterpart port on a cable or DSL modem. In the larger enterprise, a WAN port may hook up to a T1 line or other wide area network service and use a V.35, RS-232 or RS-530 connection.