If you really must set up telnet, and you have been warned that is about as secure as shouting your password in a shopping mall, then you can do it like this:
- Open a terminal
- Enter 'sudo pico /etc/inetd.conf' (for 10.2 you will need to edit xinetd instead)
- Remove the hash at the start of the line that reads "#telnet .... ... " and so on. In effect, you want to un-comment this line.
- Ctrl X to exit, say yes to save the changes.
- You might have to restart (perhaps).