When most people think of the Internet, they really mean the Internet. However, the physical network that makes up the Internet contains much more than just the websites and public services that we all use every day.
In fact, most of the Internet is not connected to the Internet at all, but rather a whole range of other Internet services that use different “protocols“. HTTP or Hypertext Transfer Protocol is used, for example, to serve websites in your browser. Telnet is also an Internet protocol, but with a different history and some interesting uses.
But what is telnet? This article will tell you about it.
What is Telnet?
Tim Starling (WMF) / CC BY-SA (https://creativecommons.org/licenses/by-sa/4.0)
Telnet is a text-based networking protocol that allows a client (that is, you) to communicate with a remote computer somewhere on the Internet. Typically Telnet connections work over port 23, and like websites, Telnet services have a specific address.
In the past, you could use a dedicated terminal to access the Telnet service. Terminals are not really full-fledged computers, but simply devices that provide a remote â€œfaceâ€ of a remote computer.
Almost everything from smartwatches to smart TVs these days has full processing power, so silly terminals no longer make much sense. To use the Telnet service today, you need an application known as the Terminal Emulator . The good news is that there are many great free terminal emulators for every operating system.
You might think Telnet doesn’t sound that relevant anymore. Although it is a lesser known internet service, there is a sizable and dedicated Telnet community around the world.
It also continues to play a very important role in the remote control of low bandwidth computers. This means that Telnet is not only far from death, but also has a bright future ahead of it. However, before we get to that, let’s take a quick look at where Telnet came from.
A Brief History of Telnet
Eric Pitti / CC BY (https://creativecommons.org/licenses/by/2.0)
Before the Internet today, the ARPANET existed. The military and academic computer network at a time when the only people who had computers worked for government agencies or institutions. The computers in question were huge machines that filled entire rooms. This was before the idea of ??a personal computer came to mind.
Getting computers to communicate with each other over this new network was no easy task. Mainly because each of these machines had very different designs and architectures.
What was needed was a single common language. In 1971, the first Telnet proposal was developed. However, it took more than ten years for Telnet to become a working technology. In 1983, the very first iteration of the Telnet protocol was released to the world.
Telnet as a remote management tool
Telnet can be used to send commands to remote systems and therefore to control them through the terminal interface. This is rarely done these days, as the SSH (Secure Shell) protocol largely replaces the purpose and functionality of Telnet.
However, Telnet is still important because systems that run operating systems from earlier eras but are still in use today can only be accessed via Telnet. Some internet devices, such as certain routers, can also only respond to Telnet commands.
This is actually one of the key benefits of Telnet. It is such an old and fundamental protocol that you can often rely on its reliable and stable performance. After all, his goal was to become a universal language for computers to send and receive commands. However, it should not be used as a first line technology, if at all possible. Secure Shell is generally the best choice in almost any situation
What is Telnet vs Secure Shell
Telnet was developed at a time when the idea of ??cybersecurity was of no concern to anyone. Since only trusted individuals had computers with network access, the idea that someone would hack into a computer was rather far-fetched.
Today billions of people have a computer as well as an Internet connection. Hackers are constantly attacking remote systems, which means they are always looking for a new vulnerability. Since Telnet sends its commands in plain text and everyone knows which network port it uses by default, it is quite easy to intercept or modify data.
Secure Shell solves this problem by using strong encryption of all data sent and received. This is one of the main reasons it supplanted Telnet. That being said, there are also ways to apply encryption to Telnet these days, although this is not an integral part of the protocol
How to access the Telnet service
To connect to the Telnet service, all you need is a terminal emulator and the address of the computer you want to connect to.
There are many terminal emulators out there. Most of them are free. In this case, we will use the popular term Tera Term. As a demonstration, we’ll connect to a Telnet service that uses ASCII text to retell the entire first Star Wars movie.
Typically in a traditional terminal application, you would type telnet followed by a space and the address of the service. You may also need to specify a port in the command, which is usually port 23 for Telnet. However, Tera Term has a graphical interface, so all we have to do is fill the screen this way.
As you might guess, the address of this service is towel.blinkenlights.nl. When everything is set up as above, just click OK and it will happen.
Awesome! Right? We will not stop there. Here are some more Telnet services that you can play with while you don’t have a terminal application.
Great Telnet Services
Now that we’ve covered the basic facts about Telnet, there is no better way to complete this crash course than by pointing you to some interesting places you can visit right now.
Telnet.org maintains a huge list of Telnet places to visit. You should head there to get to lesser-known spots, but here are the highlights that most people will enjoy:
From here you are on your own. But if you have the patience, the Telnet world can be very rewarding to explore and experiment. You will immediately dream in ASCII!