Remote service login – Telnet

Telnet is one the earliest remote login protocols still in use. It is older than most of the system administrators today, as it was developed in 1969. Telnet allows users to make text-based connections between computers. Since Telnet provides no built-in security measures, it suffers from various security issues.

Getting ready

To demonstrate the use of Telnet, we will use two systems. On the first system, a Telnet server will be running, and from the second system, we will check the security issues.

How to do it...

In this section, we will see how Telnet can cause serious security issues:

1. Using Telnet is very easy. Just open a terminal window and type the following command:

telnet <IP Address> <Port>

Here is an example: telnet 192.168.43.100 23

2. When Telnet is running on a server, it can be used by attackers to perform the banner grabbing of other services. Let's use it to find the version of SSH running on the server. Type the following command to do this...