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TELNET Port Number | What is port number of TELNET protocol

This page mentions TELNET Port Number. The port numbers of protocols such as TELNET, FTP, DHCP, HTTP, SMTP etc. are defined as per RFC 1700.

What is Port Number ?

The end point of a logical connection is known as port. Port number is logical address of each application or process or program which uses network or internet connection in order to communicate. In TCP/IP network, it helps sender and receiver to communicate with each other. Port number is 16 bit in size which takes any value from 0 to 65536. The port numbers from 0 to 1024 are known as well known ports and are used for specialized services or privileged services. TELNET port number is 23.

IP address and port number are used to deliver data packets to its destination device. IP address resembles to apartment building or flat building housing multiple flats/apartments. The port number resembles to individual apartment or flat number. IP address/port number can be written as where in first four digits are IP address and last digit "8080" is port number.

What is TELNET Protocol?


• Telnet allows users to connect and log on to any other hosts in the network from their computer by using login credentials (user name, password).
• Telnet uses TCP protocol for connections.
• Telnet service is available on port 23 of the host machine.
• Telnet client acts as terminal which accepts any keystrokes from the keyboard, interpret them and display output on screen. Client on the computer makes TCP connection to port 23 of the host machine where Telnet server answers. Telnet server interacts with applications in the host machine and assists in terminal emulation process.
• Refer advantages and disadvantages of TELNET protocol >> for more information.

Table of port numbers vs Protocols

Port numbers are pre-assigned by IANA (Internet Assigned Numbers Authority). They are specified in RFC 1700. Following table mentions port numbers for FTP, TELNET, HTTP, SMTP, POP3, IMAP, BIOS, SSH, DHCP protocols. These protocols are used in TCP or UDP connections in computer networks.

Port Number Protocol description
20, 21 port number 20 is used for FTP data while port number 21 is used for FTP Control
23 Used for TELNET
80, 8080 HTTP
161 SMTP (Simple Mail Transfer Protocol)
110 POP3
143 IMAP i.e. Interim Mail Access Protocol
137, 138, 139 port number 137 is used for BIOS Name service, 138 for NetBIOS-dgm, 139 for NetBIOS Datagram service
22 Used for SSH remote login protocol, SSH is short form of Secure Shell
67, 68 The port number 68 is used for DHCP client and 67 is used for DHCP server
53 DNS (Domain Name System)
69 TFTP (Trivial File Transfer Protocol)
70 Gopher services
79 Finger
161 SNMP
179 BGP (Border Gateway Protocol)
389 LDAP (Lightweight Directory Access Protocol)
5800, 5900 VNC

Networking related links

Basics of OSI and TCPIP layers
ARP Request and ARP Response
TCP IP packet format
Networking Gateway
What is Router
What is an IP address
network switch
network bridge
Hub and Types of Hub
What is MAC address

What is Difference between

hub Vs switch  circuit switching Vs packet switching  firewall Vs router  HDLC Vs PPP  IGRP Vs EIGRP  router Vs bridge  switch Vs router  WLAN Vs Ethernet LAN  LAN vs WAN vs MAN 

RF and Wireless Terminologies

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