TCP and UDP portThis is a list of Internet socket port numbers used by protocols of the Transport Layer of the Internet ProtocolSuite for the establishment of host-to-host connectivity.Originally, port numbers were used by the Network Control Program (NCP) in the ARPANET for which twoports were required for half duplex transmission. Later, the Transmission Control Protocol (TCP) and the UserDatagram Protocol (UDP) needed only one port for full duplex, bidirectional traffic. The even numbered portswere not used, and this resulted in some even numbers in the well-known port number range beingunassigned. The Stream Control Transmission Protocol (SCTP) and the Datagram Congestion Control Protocol(DCCP) also use port numbers. They usually use port numbers that match the services of the correspondingTCP or UDP implementation, if they exist. The Internet Assigned Numbers Authority (IANA) is responsible formaintaining the official assignments of port numbers for specific uses. [1] However, many unofficial uses of bothwell-known and registered port numbers occur in practice.