Telnet vs SSH: Understanding the Difference

In this article, you will learn the difference between telnet and ssh.

Telnet and SSH are protocols that allow you to access and manage devices remotely. While Telnet has been around since before the dawn of the internet, SSH offers a modern alternative. These network protocols have many similarities, but understanding their difference can help you know which option is best for your needs. 

This guide will break down the key differences between Telnet vs SSH and why many users are switching to SSH protocol. Read on to learn more about these two network protocols. 

What is Telnet?

Telnet is a network protocol that provides a two-way collaborative channel between two remote machines. 

Telnet uses a text-based interface. This protocol sends the data in plain text from one device to another without requiring authentication or security. Because Telnet lacks adequate security measures, it is best for private networks not connected to the internet. 

Telnet was developed in 1969, years before the development of the World Wide Web. This protocol originated as a method for university students and professors to log into the university’s portal from any device on campus. Telnet technology was revolutionary at the time, creating a path for the World Wide Web 20 years later. 

Today, the most common use of the Telnet protocol is by network admins who require remote access to the devices within a private network. Admin can use this protocol to access the IP address of a remote device, then control any application on it. 

For many decades, Telnet has served as an adequate solution to establish remote connections between systems. 

What is SSH?

SSH (Secure Socket Shell) is a network protocol that allows two devices to communicate and transfer data. Unlike Telnet, which does not secure data transfer, SSH encrypts data between two devices, making it usable on public networks or other insecure networks. 

When SSH encrypts the data for transfer, it becomes very challenging to decrypt and read. As a result, SSH offers a secure protocol solution for sending passwords, vulnerable data, and private information between remote devices. SSH encrypts data traveling in both directions through the protocol, delivering top-level security. Some SSH programs will let you define the level of encryption to increase security and meet requirements (PCI, HIPAA, FIPS).

The first version of SSH was developed in 1995 by the cybersecurity vendor SSH Communications Security. Like Telnet, SSH enables you to log into a device or a network and open any applications on the device. You can also move files from one device to another using SSH. 

Differences Between Telnet and SSH

telnet vs ssh client

While Telnet and SSH have similar functions, they also include many differences. Here are the primary differences between Telnet vs SSH: 

First, the mechanics behind these network protocols are slightly different. For example, Telnet allows you to connect to a remote system in a way that makes your device appear as a local system. Meanwhile, SSH enables you to log into another device remotely over the same network, then execute functions on the remote device. 

Next, as we’ve mentioned, SSH is more secure than Telnet. SSH encrypts data on both remote devices before transferring it. This process makes the data very challenging for unauthorized users to decipher. In contrast, Telnet sends data in plain text without encrypting it. 

Because of Telnet’s lack of security, this protocol is best suited for data transfer or remote access across a private network. Meanwhile, SSH is suitable for public networks where encryption is necessary to protect data from public users. 

Next, these protocols use different ports. Telnet operates with Port 23, while SSH uses Port 22 by default. However, you can easily change the port number when running the SSH protocol. 

Telnet and SSH are also compatible with different operating systems. While Telnet only works with Windows and Linux, SSH is compatible with all popular operating systems, including Mac. 

These protocols also have different authentication mechanisms. For example, while Telnet uses no authentication, SSH uses public-key encryption to authenticate users. Public-key encryption has high cryptographic strength, ensuring that no unauthorized users gain access to the network through the SSH protocol. 

Next, these network protocols have different bandwidth usages. Telnet has low bandwidth usage, while SSh uses high bandwidth. As a result, SSH can transfer data faster than Telnet in many cases. However, running the SSH protocol also uses additional energy consumption for data transfer compared to Telnet. 

Because of these differences, many users view SSH as the superior alternative to Telnet. However, both network protocols have their uses within remote access and management processes. 

What Is the Advantage of SSH Over Telnet? 

ssh advantage over telnet

The primary advantage SSH offers over Telnet is security. 

Telnet offers practically no security for data transfer and remote access. This network protocol transfers data in plain text, allowing unauthorized users to access and steal the data easily. This makes Telnet highly vulnerable unless used across private, secure networks. 

However, using SSH can ensure that the data you transfer across remote devices remains secure. SSH uses key-pair encryption for authentication, which is incredibly difficult to decrypt. As a result, you can feel confident that data exchanged across SSH protocols will remain safe. 

Telnet’s security mechanisms are simply outdated. Telnet is practically as old as the internet, and security breaches weren’t as big of a threat during its origins. However, in modern-day, keeping data secure is essential to the livelihood of businesses and organizations. Many companies cannot risk their data’s security by using an outdated protocol like Telnet. 

SSH also boasts greater compatibility than Telnet. Telnet is only compatible with Windows and Linux operating systems, while SSH works within most modern operating systems. 

SSH excels in security, authentication, versatility, and data transfer formats. 

When To Use Telnet

Telnet works best when used across private networks. 

Private networks typically present a lower risk of data breaches. Most users within a private network have similar authorizations, preventing users from attempting to access unauthorized devices. Additionally, Telnet’s lack of security isn’t an issue across trusted networks that are not connected to the internet, as no unauthorized users can access these networks. 

You can also consider using Telnet on devices that don’t support SSH. Even though SSH has broader compatibility than Telnet, certain outdated devices may not support SSH protocols. In these cases, you can turn to Telnet as a backup. 

However, we do not recommend using Telnet across public networks. 

When To Use SSH

We recommend using SSH in any scenario you can. Because this protocol provides superior security to Telnet, you can feel confident using it across various applications. 

Specifically, you should always use SSH when connecting to remote devices across public or internet-connected networks. SSH will encrypt the data you transfer to the remote device, keeping it safe from unauthorized users. A good example of using SSH is when connecting to a Cisco switch or router. This will ensure all the traffic from your computer to the remote Cisco device is encrypted.

You should also use SSH on operating systems that do not support Telnet. While Telnet is only compatible with Linux and Windows, SSH is compatible with most popular operating systems, including:

  • macOS
  • Linux
  • Windows – Microsoft now includes OpenSSH in Windows 10 and later operating systems. This is the first time Microsoft has includes an SSH tool by default in Windows.
  • OpenBSD
  • Solaris
  • OpenVMS
  • NetBSD
  • FreeBSD

Now that you know the differences between Telnet vs SSH, you can determine which network protocol is suitable for your desired usage. While both protocols have similar functions, SSH excels in security and compatibility, making it the preferred choice for many system admins. However, Telnet still has its place among private networks and outdated systems. 

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