SSH VS TELNET – Difference between SSH and Telnet

Rashmi Bhardwaj | Blog,BUZZ,Protocol

Telnet is the protocol that allows a user to communicate with a remote device. It is used mostly by network administrators to remotely access and manage devices.

An administrator can access the device by telnetting to the IP address or hostname of a remote device.

To use telnet, a software (Telnet client) must be installed. On a remote device, a Telnet server must be installed and running. Telnet uses TCP port 23. Telnet was designed to work within a private network and not across a public network where threats can appear


SSH is the protocol used to remotely access and manage a device. SSH uses encryption, which means that all data transmitted over a network is secure from eavesdropping.

Like Telnet, a user accessing a remote device must have an SSH client installed. On a remote device, an SSH server must be installed and running. SSH uses TCP port 22 by default.

SSH offers security mechanisms that protect the users against anyone with malicious intent while Telnet has no security measures. The security issues of Telnet required a people to use SSH in order to protect network.

Enlisted below are the key similarities between SSH and Telnet –

  • Both are network protocols which allow users to login to remote systems and execute commands on them.
  • Access to command line of a remote host is similar in both protocols
  • Both use TCP protocol
  • Both work in Client-Server Model
  • Both are terminal based protocols

Below table elaborates the difference between both the protocols –

Highly secured
Less secured than SSH
Port number
Uses TCP port number 22
Uses TCP port number 23
Data format
SSH sends all the data in encrypted format. SSH uses a secure channel to transfer data over the network
Telnet sends the data in plain text.
SSH uses public key encryption in order to authenticate the remote users
Telnet uses no authentication mechanisms
Data Privacy
Usernames and Passwords can be prone to malicious attack
Data sent using this protocol cannot be easily interpreted by the hackers.
Public/Private network recommendation
Suitable for Public networks
Suitable for private networks
Can be considered a replacement of telnet since has overcome many of security issues of telnet
Is older than SSH and has many vulnerabilities than SSH.
Bandwidth usage
High bandwidth usage
Low bandwidth usage
Operating system
All popular Operating systems
Used in Linux and Windows Operating system.
RFC 4253 specifies SSH server
Telnet was developed in 1969 beginning with RFC 15 and extended in RFC 854

Download the difference table here.


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