Network Ports

In computer networking, there are network port numbers used for various applications. The range of these network ports are from 0 to 65535. There are three different port types used networking. These network port types are given below:

• Well-known Ports
• Registered Ports
• Dynamic Ports

Some of these port numbers are well-known ports. These well-known ports are the reserved ports between 0 and 1024. The full list of these network port numbers are given in RFC 1700. IANA (Internet Assigned Numbers Authority) assigns these well-known ports.

The other network ports are registered ports between 1024 and 49151. These portsa re assigned by IANA for specific services.

The last part of ports in networking are dynamic ports. Daynamic ports are the ports from 49152 to 65565. These ports in networking are not registered with IANA.

TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) uses these well-known ports. Only one port is required for full-duplex, bidirectional traffic. Beside SCTP (Stream Control Transmission Protocol) and DCCP (Datagram Congestion Control Protocol) use these ports.

You can download the Cheat Sheet about Well-known network ports.

Well Known Ports in Networking

Well-known network ports are from 0 to 1024. These port numbers are given by IANA (Internet Assigned Numbers Authority). And the full list of these port numbers are in RFC 1700.

Some of these  well-known ports are used by TCP and some of them are used UDP. These TCP and USP ports are also asked in many network engineering technical interviews as interview questions. So, what are these ports in networking?

Well-known TCP ports are the network ports used by the applications that works with TCP as transport protocol. So, what are these applications that uses well-known TCP ports?

For example, FTP (File Transport Protocol) is one of the applications that uses TCP ports. The FTP ports are TCP port 20 and TCP port 21. The other applcation that uses TCP as transport protocol is Telnet. Telnet uses TCP port 23.

Well-known UDP ports are the network ports used by the applications that works with UDP as transport protocol. So, what are these applications that uses well-known UDP ports?

For example TFTP (Trivial File Transport Protocol) is one of the applciations that uses UDP ports. UDP port 69 is used by TFTP. Another example that uses UDP as transport protocol is SNMP. SNMP uses UDP port 161 for SNMP and UDP port 162 for SNMP trap messages.

Below, you can find all the wellknown ports used by the applications that uses TCP & UDP network ports.

Registered Network Ports

Registered networking ports start from port 1024 to 49151. IANA (Internet Assigned Numbers Authority)  assigns these registerd network ports. Below, you can find these registered networking ports

Dynamic Networking Ports

Registered networking ports are the ports from 49152 to 65565. These ports can be used locally or dynamically by the applications. They are not assigned by IANA.

gokhankosem

Gokhan Kosem is a Network Engineer, Instructor and the Founder of IPCisco.com with 15+ years of experience in Cisco, Nokia, Huawei, Juniper, Linux, Service Provider Networks, Routing and Switching technologies.

He has worked on the backbone networks of major service providers and network vendors including Nortel, Alcatel-Lucent (Nokia) and has extensive hands-on experience with Cisco, Huawei, Juniper and Nokia networking technologies.

He has trained thousands of networking students worldwide through IPCisco.com, Udemy, books, labs, quizzes, and educational content across multiple social media platforms.

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