Question: A port number is _______ bits long.

Answer:

A port number is 16 bits long, which means that it can have a maximum value of 2^16 or 65,536. The port number is used by the transport layer protocols such as TCP (Transmission Control Protocol) or UDP (User Datagram Protocol) to identify the source and destination processes in process-to-process communication. The first 1,024 port numbers are reserved for well-known services, while the rest are available for use by any application that needs them.