Computer Port numbers and port number classifications

A network port number is the communication point between the computer and the computer network. All the information. The port number is backed up with TCP or UDP. Thecomputer port number is defined in the Transport Layer of OSI reference model.

There are 65536 ports available for use in TCP or UDP.

They are divided into three ranges.

1. Welknown ports
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The Internet Assigned Numbers Authority (IANA) manages the first
1024 ports (0 – 1023). This range is known as the Well
Known Port Numbers and includes standard default
HTTP (port 80), FTP (port 21) and SMTP (port 25).
These port numbers are reserved and should not be used arbitrarily.

2. Registered ports
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The second range is the Registered Port Numbers which contains
ports 1024 through 49151. The Registered Port Numbers can be
used by ordinary programs and user processes that are executed
by the user. The use of specific port numbers is not carved in
stone. These ports are generally used transiently when needed.

3. Dynamic/Private port
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The third range is the Dynamic or Private Port Numbers which
range from 49152 through 65535. These can be used by applications
and processes initiated by the user but it is uncommon. There are
known Trojan horse and backdoor programs that use this extreme
upper range so some security administrators are leery of
traffic in this range.