3Com OfficeConnect 3C16771 - Introduction; 500 D Ort Umbers; Ip Port Numbers; Registered Port Numbers

D
IP P
ORT
N
UMBERS
This appendix contains the following:
■
Introduction
■
Well Known Port Numbers
■
Registered Port Numbers
Introduction
The port numbers are divided into three ranges:
■
Well Known ports — those from 0 to 1023
■
Registered ports — those from 1024 to 49151
■
Dynamic or Private ports — those from 49152 to 65535
Well Known Port Numbers
The Well Known Ports are controlled and assigned by the
Internet Assigned Numbers Authority (IANA)
http://www.iana.org
and on most systems can only be
used by system processes, or by programs executed by
privileged users. Many popular services, such as Web, FTP,
SMTP/POP3 e-mail, DNS and so forth operate in this range.
The assigned ports use a small portion of the possible port
numbers. For many years the assigned ports were in the
range 0–255. Recently, the range for the assigned ports
managed by the IANA has been expanded to the range
0–1023.
Registered Port Numbers
The Registered Ports are not controlled by the IANA and on
most systems can be used by ordinary user processes or
programs executed by ordinary users.
While the IANA cannot control uses of these ports, it does
list uses of these ports as convenience.