IP port addressIP port address is a portion of an IP Address, and hence of a uniform resource locator (URL). It is indicated by a number following a colon, after the final domain extension, as with the "2000" in http://corl.nbc.upenn.edu:2000/ The port address identifies a specific server service or application. The default port address for hypertext transfer protocol (http) is usually 80, although other ports may be used for security reasons.