In computer networking, a port is a logical construct that identifies a specific process or a type of network service). It is a number assigned to uniquely identify a connection endpoint and to direct data to a specific service). A port number is always associated with a network address of a host, such as an IP address, and the type of transport protocol used for communication). The most common transport protocols that use port numbers are the Transmission Control Protocol (TCP) and the User Datagram Protocol (UDP); those port numbers are 16-bit unsigned numbers). Specific port numbers are reserved to identify specific services so that an arriving packet can be easily forwarded to a running application). Ports provide a multiplexing service for multiple services or multiple communication sessions at one network address).

In summary, a port is a virtual place within an operating system where network connections start and end. It is a logical connection used by programs and services to exchange information. It determines which program or service on a computer or server is going to be used. Port numbers range from 0 to 65535 and are used to transmit data between computer networks and applications.