Service Identification in TCP/IP: Well-Known versus Random Port Numbers

Abstract

The sixteen-bit well-known port number is often overlooked as a network identifier in Internet communications. Its purpose at the most fundamental level is only to demultiplex flows of traffic. Several unintended uses of the port number evolved from associating services with a list of well-known port numbers. This thesis documents those unintended consequences in an effort to describe the port number's influence on Internet players from ISPs to application developers to individual users. Proposals and examples of moving away from well-known port numbers to randomly assigned ones are then presented, with analysis of impacts on the political and economic systems on which Internet communication is dependent.