Users can access remote systems using SSH and Telnet, two communication methods. These communication protocols specify how data, which frequently must be transported over multiple physical and digital contexts, is passed between various devices on a network. 

However, what distinguishes them, and when is it preferable to utilize one? This guide explains SSH vs Telnet, their use, and when.

What is Telnet?

Users can open a session on a distant device using the Telnet communication protocol to access particular programs or download files. Telnet is based on a client-server architecture that enables a client-machine user to access a remote server's command line. 

Nowadays, this protocol is largely out of date and primarily used for less significant tasks like connecting to a public server that still supports Telnet connections to play a retro game. 

Telnet was a mechanism for establishing remote access dependent on existing HTTP and FTP connections. Still, it wasn't secure, and anybody could see a user's username and password sent over the Telnet connection. 

It was, therefore, an inappropriate protocol for more important applications. Some of the advantages of Telnet include:

  • information can be sent and received using this protocol
  • offers user authentication support
  • enables the participation of numerous users
  • This remote login can save your research hours

What is SSH?

Secure Shell or Secure Socket Shell is referred to as SSH. SSH is a cryptographic protocol that enables two computers to exchange information and communicate over an unsafe network. SSH allows for both automated processes and secure user access. 

The shortcomings of Telnet were improved upon by the network protocol SSH. Telnet's lack of security in its remote sessions was one of its main flaws. On the other hand, SSH uses cryptographic methods to make remote sessions unavailable to an outside observer trying to eavesdrop. 

On Linux and macOS systems, SSH is the principal protocol for establishing remote access. To run shell commands and access apps on the remote system, it uses the PuTTY client. In addition, clients like Cyberduck (on macOS) offer graphical user interfaces to aid in creating remote sessions.

Some of the advantages of SSH include:

  • It is free to use for non-commercial purposes
  • The open-source version has undergone enhancements such as bug fixes and patches, providing many more functions.
  • SSH might provide several services over a single connection
  • It provides reliable authentication as well as safe communication through dubious channels.
  • Users can securely log into another machine via SSH when connected to an unsecured network.
  • It gives your data privacy by using a robust encryption.

SSH vs Telnet: what are their differences?

There is no doubt that SSH and Telnet have some similarities; however, many differences are listed below. 


Telnet needs a client application installed on the local computer and a server application running on the remote system you want to manage. Telnet uses port 23 and the TCP protocol to connect to remote systems. Then, this device serves as a Telnet server and can take orders. 

The server receives and interprets commands delivered in the NVT format before sending them to the right application. On the other hand, SSH connects securely to the server over port 22 (although it is possible to change the port number). 

With key-based authentication, a session key is created and given to both the client and the server when the client confirms the server. The traffic for the active session is encrypted using this key. To verify the client, the server generates an SSH key pair. After the client has been authenticated, the two systems safely exchange data across an encrypted connection.

SSH vs Telnet: security

Telnet alone does not use encryption because it was created before the widespread adoption of the internet, making it obsolete in terms of contemporary security. Because of this, it must only be used on secure, private networks.

The shared data during SSD sessions that use key pairs for authentication is very difficult to decrypt and read. As a result, sending data over unsafe networks using SSH is quite secure.

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SSH vs Telnet: Authentication

When establishing a connection, Telnet does not utilize any authentication methods. Public key authentication is the most used and safe SSH authentication method. The client keeps the private key of an SSH key pair while the server receives the public key. 

When a client wants to connect to a server using SSH, the server verifies the client's identity by comparing the client's public and private keys. The two systems can connect securely if their keys match.

Data formats

Telnet uses the NVT format to send data as plain text. On the other hand, SSH transmits data in an encrypted format over a secure connection.

SSH vs Telnet: when should you use them?

There are two situations where it is advised to use Telnet rather than SSH because Telnet is significantly less secure than SSH:

  • when working on secure networks that are not connected to the Internet, such as LANs
  • when working with hardware that isn't SSH-compatible
  • for maintaining and connecting to text-based bulletin board systems

In these circumstances, Telnet's lack of security ceases to be a problem, and lower bandwidth utilization starts to be advantageous. You should always utilize SSH to connect to a remote system over the Internet due to its extremely secure nature.

Additionally, SSH provides additional features than Telnet, including encrypted file transmission and port forwarding.


To access the resources of a distant machine, we can utilize various application programs. Telnet and SSH are the two main client-server application programs that use remote terminal service. 

These programs let a user at one location communicate with a remote timesharing system at a different location as if the user's keyboard and display were physically connected to the remote machine. Even though both SSH and Telnet are commonly utilized to access servers, as we discussed before remotely, they have significant distinctions.

When considering SSH vs Telnet, the most significant difference is that Telnet sends information as simple plaintext, but SSH employs an encrypted format and a secure channel to send information.

SSH is a more secure option than Telnet in terms of security. Telnet does not offer much protection, but despite this, it is still commonly used today. Although Telnet and SSH can both be used to transfer data to remote servers, SSH is strongly advised instead.

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