Rlogin vs Telnet
Rlogin and Telnet are two very similar protocols as they both allow a user to remotely connect to another computer and then send commands that are executed on that computer. They both allow a person to manipulate and extract data from a computer even without being physically in contact with it. But, there are a couple of major differences between rlogin and telnet. The most major difference between rlogin and telnet is in the way that rlogin allows the credentials of the client to be stored in a local rhosts file so that the just needs to access the remote server and he is connected automatically. The client program passes the credentials automatically. This can be both for password and username or password only. The problem with this is that leaving a terminal unattended leaves not only that terminal vulnerable but also all the other remote computers that has entries in the local rhosts file. It is not implemented in telnet, thus there is no risk of exposing the server to unnecessary risk.
The first one is the ability to pass settings and environment variables as parameters. Of course, you can also change the settings and environment variables by entering commands after the session is established, but for many, it is an unnecessary step. It was later discovered though that this feature exposes the server to security risks. Thus, many servers disable the use of this feature even if it slightly inconveniences the client.
But the most important thing about these two is the same with both and not actually a difference. Both rlogin and telnet are not secure protocols that send messages in plain text; a form that is easily readable when intercepted. So, the use of both is not advisable when routing through public networks like the internet. Even when restricted to a local private network, the use of either rlogin or telnet is still discouraged. For security reasons, rlogin and telnet are no longer being used. Other protocols like SSH has largely taken over for these two protocols.
Summary:
- Telnet allows the user to pass environment variables as parameters while Rlogin does not
- Rlogin allows the user to automatically connect while Telnet does not
- Both rlogin and telnet are not secure enough for public use