What is a Port Number?

A port number is an identification of communication to a resource in the server. The server (TCP/IP) determines what information is requested from this number and then calls the respective program to attend to that specific request.

Reserved or Well known port Port numbers between 0 - 1023 port number (IANA registered) Registered ports Port numbers between 1024 - 49151 (IANA registered) Dynamic ports Port numbers between 49152 - 65535

For more information on port numbers refer http://www.iana.org/assignments/port-numbers