Security - TCP/IP Port Numbering

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. 

The range for assigned ports managed by the IANA are those numbers between 0 and 1024.  Ports beyond these ranges are known as extended ports.  Here is a listing of extended ports numbering:

• TCP Port 1025 to 1352  (1353 to 1497) | (1498 to 2048)
• TCP Port 2049 to 2500  (2501 to 2810) | (2811 to 3360) | (3361 to 6700) 
• TCP Port 6701 to 65301

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].

Updated On: 15.02.13