Practical Packet Analysis

Telnet Protocol

telnet.pcap

The telnet protocol (RFC 854) is an unsecured, text-based way for a server and client to communicate. It is often used to remotely administer servers, switches, routers, and other network hardware devices.

In this capture file you will see an example of a client computer (192.168.0.2) connecting to a telnet server (192.168.0.1). As you begin to step through the data being transmitted, notice that everything is sent in clear text. For this reason, the telnet protocol should not be used to transmit sensitive data.

Note

You can be more secure by forgoing telnet and using SSH instead.

What type of communication is occurring in this exchange between server and client? Starting at the top, we can immediately draw several conclusions. ...