In computer networking, port numbers are part of the addressing information used to identify the senders and receivers of messages.
Port numbers are associated with TCP/IP network connections. They allow different applications on the same computer to share network resources simultaneously. Home network routers and computer software work with these ports and sometimes support configuring port number settings.
Port numbers are associated with network addresses. For example, in TCP/IP networking, both TCP and UDP utilize their own set of ports that work together with IP addresses.
Port numbers work like telephone extensions. Just as a business telephone switchboard can use a main phone number and assign each employee an extension number (like x1818, x1919, etc.), so a computer has a main address and a set of port numbers to handle incoming and outgoing connections.