PORT NUMBERS

(last updated 18 August 2005)

The port numbers are divided into three ranges: the Well Known Ports,
the Registered Ports, and the Dynamic and/or Private Ports.

The Well Known Ports are those from 0 through 1023.

The Registered Ports are those from 1024 through 49151

The Dynamic and/or Private Ports are those from 49152 through 65535

The Well Known Ports are assigned by the IANA and on most systems can
only be used by system (or root) processes or by programs executed by
privileged users.

Ports are used in the TCP [RFC793] to name the ends of logical
connections which carry long term conversations.  For the purpose of
providing services to unknown callers, a service contact port is
defined.  This list specifies the port used by the server process as
its contact port.  The contact port is sometimes called the
"well-known port".

To the extent possible, these same port assignments are used with the
UDP [RFC768].

The range for assigned ports managed by the IANA is 0-1023.

http://www.iana.org/assignments/port-numbers