Telnet versus SSH

[sonc]

I've disabled telnet on my receiver, and only use ssh. This is due to the fact that telnet sends everything over the network in plain text, including username and password.

This is an overview of the differences between the 2 protocols.

SSH, i.e. Secure Shell, and Telnet are two network protocols that are used to connect to remote servers in order to facilitate some sort of communications. The primary difference, which has also led to one superseding the other, is in security.

SSH offers security mechanisms that protect the users while Telnet has no security measures whatsoever.

Telnet was designed to work within a private network and not across a public network where threats can appear. Because of this, all the data is transmitted in plain text, including usernames and passwords.

This is a major security issue and the developers of SSH used encryptions to make it harder for other people to sniff the password and other relevant information. Telnet also omits another safety measure called authentication. This ensures that the source of the data is still the same device and not another computer imitating the MAC address of the original. Without authentication, another person can intercept the communication and do what he wishes. This is also addressed in SSH as it uses a public key to authenticate the source of the data.

Due to the security measures that were necessary for SSH to be used in public networks, each packet contains less data to make room for the data of the security mechanisms. In order to transmit the same amount of data, you would need to take-up a lot more bandwidth. This is called overhead and was a major issue back when internet speeds were very low e.g. using a 56k modem, because it translates to a performance hit. This is no longer an problem as broadband speeds make this negligble.

The security issues of Telnet forced a lot of people to use SSH in order to protect themselves. It didn’t take a long time before SSH replaced Telnet in a great majority of its uses. Telnet did not fade away though as it is still used in some areas, mostly in testing and debugging.

Summary:

1. SSH and Telnet commonly serve the same purpose
2. SSH is more secure compared to Telnet
3. SSH encrypts the data while Telnet sends data, including passwords, in plain text
4. SSH uses a public key for authentication while Telnet does not use any authentication
5. SSH adds a bit more overhead to the bandwidth compared to Telnet (no longer an issue)
6. Telnet has been replaced by SSH in almost all uses

[alizaza]

I've disabled telnet on my receiver, and only use ssh. This is due to the fact that telnet sends everything over the network in plain text, including username and password.

This is an overview of the differences between the 2 protocols.

SSH, i.e. Secure Shell, and Telnet are two network protocols that are used to connect to remote servers in order to facilitate some sort of communications. The primary difference, which has also led to one superseding the other, is in security.

SSH offers security mechanisms that protect the users while Telnet has no security measures whatsoever.

Telnet was designed to work within a private network and not across a public network where threats can appear. Because of this, all the data is transmitted in plain text, including usernames and passwords.

This is a major security issue and the developers of SSH used encryptions to make it harder for other people to sniff the password and other relevant information. Telnet also omits another safety measure called authentication. This ensures that the source of the data is still the same device and not another computer imitating the MAC address of the original. Without authentication, another person can intercept the communication and do what he wishes. This is also addressed in SSH as it uses a public key to authenticate the source of the data.

Due to the security measures that were necessary for SSH to be used in public networks, each packet contains less data to make room for the data of the security mechanisms. In order to transmit the same amount of data, you would need to take-up a lot more bandwidth. This is called overhead and was a major issue back when internet speeds were very low e.g. using a 56k modem, because it translates to a performance hit. This is no longer an problem as broadband speeds make this negligble.

The security issues of Telnet forced a lot of people to use SSH in order to protect themselves. It didn’t take a long time before SSH replaced Telnet in a great majority of its uses. Telnet did not fade away though as it is still used in some areas, mostly in testing and debugging.

Summary:

1. SSH and Telnet commonly serve the same purpose
2. SSH is more secure compared to Telnet
3. SSH encrypts the data while Telnet sends data, including passwords, in plain text
4. SSH uses a public key for authentication while Telnet does not use any authentication
5. SSH adds a bit more overhead to the bandwidth compared to Telnet (no longer an issue)
6. Telnet has been replaced by SSH in almost all uses

Considering that SSH is much more secure than Telnet, it is helpful for almost all use cases, particularly for public networks. Compared to Telnet, SSH also offers more functionality, such as secure file transfer and port forwarding. However, there are two cases in which using Telnet over SSH is recommended:

When working on trusted and private networks, such as LANs, you can use Telnet
When using devices that can’t support SSH
In these situations, Telnet’s lack of security stops being an issue, and at the same time, the lower bandwidth usage counts as a benefit. In this section of the article, we compared Telnet vs. SSH from different angles. In the next paragraph, you will get familiar with their main advantages and disadvantages.