When you use an ordinary telnet program to connect to a host, it does not encrypt the data it sends. As a result, it is possible that passwords and other sensitive data that you type could be eavesdropped from the network. To prevent this from happening, telnet servers on Facilitized Unix hosts use Kerberos to authenticate users and encrypt connections. Most recently deployed Facilitized Linux/Unix hosts will only accept secure telnet connections
One important note about using the Facilities Kerberized telnet client is that, in order for the connection to be secure, the machine that you are connecting to must be running a Kerberized telnet server. For this reason, and because of the widespread availability of SSH, it is recommended that you use SSH instead of telnet.