Networking Technology: Telnet and SSH

If there is a protocol that existed before the mainstream adaptation of internet, it is Telnet. Some might even call it an ‘outdated’ protocol, but one that led to many new ones. The word telnet stands for ‘Teletype Network’ and is sometimes used as a verb ‘to telnet’.

Origin of Telnet

 The first version of telnet came around in the late 1960’s when ARPANET was the talk of the town. In those times, computers needed to connect remotely to others. This is when researchers got together and developed telnet protocol in 1971. Since then, the protocol has been revised multiple times to accommodate better connections.

How Telnet Works

 Telnet gives users a two-directional text-only communication system using a virtual connection over 8 bytes. In simple words, telnet is a protocol that can open a command line on a remote computer which is typically a server. You can use this tool to ping a port and check if it is open. Working with a virtual terminal connection emulator or a connection to a computer with standard protocols, the connection acts just like a physical connection to a machine. The virtual connector is an environment where many computers have the same rules to send and receive messages.

Users can also use FTP to send data files across. Connecting remotely to a machine using telnet is also termed as ‘telnetting into a system’. Access is granted to the remote computer when the user enters a username and password. Once granted access, the connection works in the same way as if the user was logged into the computer in person. No matter what your physical location, the IP of the computer will be applied, and not of the user’s location.

Telnet Uses

 Telnet proves useful for a variety of functions on a server like file editing, checking emails and running various programs. For instance, some servers use telnet to access public data to enable users to play games or check the weather forecast. You can also use this protocol to sign into unencrypted, text-based protocols, be it web servers or ports. telnet is also used to troubleshoot mail or remote web servers and some trusted internal networks.

Drawbacks and Criticism

You can classify telnet as an old technology. Many uses are now carried out by web-based servers and systems, but telnet is still used extensively. Computer scientists also call telnet a security risk because it does now have encrypted communication. It means that any intruder can barge into the connection and steal data or modify messages.


 This situation led to the development of SSH or Secure Shell. SSH is a remote-access protocol like telnet but it gives users and system administrators a secure path to access a system on an unsecured network. Secure Shell gives you encrypted data communication, strong password authentication and a public key authentication. In essence, SSH applies both to the network and to the range of utilities implementing this protocol.

How SSH Works

 SSH works to replace the old and insecure network protocols. The most basic use of SSH is to connect to a remote host with an ID and username. If you are connecting for the first time, the user will be asked for the host’s public key fingerprint. The key will then be stored and won’t be asked the next time you connect. SSH is widely used because of telnet’s short comings. Because of the security in SSH, the future of telnet looks bleak.


While both Telnet and SSH have the same goals, SSH is a more advanced protocol that comes boasts enhanced features. Companies are recommended to use SSH because it utilizes encryption for most transmitted layers. This minimizes the risk of security breaches and strengthens the network against replay/insertion, eavesdropping, and MITM (man in the middle) attacks.