I have a client who I occasionally do some trouble-shooting for. I recently talked him into installing a knoppix machine to use as a simple email/proxy server.

He just emailed me to say that he tried to get telnet** running on it, but was having trouble.

In less time than I would have been on hold for with some "commercially supported" software, I searched for 'telnetd' in this very forum, and found the answer to the problem (thanks to averylowiq) .

You just can't buy the sort of support that you can find on this forum.

**Yes I did warn him of the dangers of using telnet, and suggested he stick to using ssh.