What is Telnet?

Telnet is one of the protocols that is used both on the internet and LAN (Local Area Network). In other words, Telnet is a protocol that is used in order to get access to the remote computer or the terminals. It makes connections over the internet using the TCP/IP protocol.

Telnet is often referred to as TN. It was first conceived back in 1969, by the IETF (Internet Engineering Task Force).  Telnet stands for the Teletype Network.

Telnet is especially designed for remote server access where we can manage all the client/server architectures. There are also other commands that we need to insert in order to successfully complete the Telnet operation. Device must be supported for the commands in order to use Telnet. There might be some devices that are not supported and hence we can’t execute the command in those devices.

Working

Telnet basically sends all the messages in plain and clear text. It means there is no specific mechanism for security. Therefore, it is not considered that secured and people don’t prefer sending their personal data over telnet. This is one of the biggest disadvantage we see in the Telnet. Moreover, there is no proper authentication required. In other words, we can’t ensure that data is just transferred between two of the host and there is no interception in the middle. Therefore, this is another problem that is happening when it comes to the security of the Telnet.

However, now in many services and applications, there are improved measures taken in order to make it more secure. Therefore, there are many applications where the Secure Shell (SSH) is replacing Telnet.

Telnet Clients

There are many clients available for Telnet utility. Some of them are as follows –

• Putty and Plink – These both are the free and the open source SSH clients that can be used. They both are compatible with the Raw TCP clients for Windows, Unix, as well as for the Linux.
• There is another client called AbsoluteTelnet available for the windows. Here, we will also find the SSH and SFTP support.
• Rumba is the terminal emulator for the Telnet.

These are some of the clients we may like to use. However, we will also need the support of the libraries in order to transmit the data, which brings us to the next topic.

Telnet Libraries

There are many telnet libraries where the client and the server are supported. In some of the libraries, the security is not maintained.

Here are some of the famous libraries used and related information –

Go-telnet: In this library, the client and the server support is available. Along with this, the security is also taken care of and we can use TELNET for the data transmission.

Libtelnet: Here, we can use it for client and server. However, security is not maintained here. The license of this library is in the Public domain.

Telnetlib: Here, the only client is supported and we won’t get the support for the security or the server.

All the libraries are available on all the platforms. Hence, we can use this library on BSD, GNU Linux, Windows, and also on Mac OS. Therefore, we can use the libraries according to the requirements. The programming language is different here. However, most of the people are using the Go-telnet as most of the things are supported and people also want security over their data.

Related – SSH vs Telnet