The Telnet protocol was designed to remotely login to computers via the network. Although its main purpose is to access a remote standard terminal, it can be used for many other functions as well.

The protocol follows a simple scenario. The client opens a TCP connection to the server at the port 23. The server authenticates the client and opens a terminal. At the end of the session the server closes the connection. All data is sent in plain text format whithout any encryption.