# Forum in English  > Internet security for beginners  > Microsoft Windows  >  PORT NUMBERS

## SDA

(last updated 2008-03-06) 

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.

DCCP Well Known ports SHOULD NOT be used without IANA registration.
The registration procedure is defined in [RFC4340], Section 19.9.

The Registered Ports are those from 1024 through 49151

DCCP Registered ports SHOULD NOT be used without IANA registration.
The registration procedure is defined in [RFC4340], Section 19.9.

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

A value of 0 in the port numbers registry below indicates that no port 
has been allocated.

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

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