Classnotes | UNIX01 | RecentChanges | Preferences If you have worked with computers on the internet for longer than a few years, chances are you have encountered Telnet. Telnet is a means by which you can connect remotely to another machine.
Telnet is fast and simple, but unfortunately has one very serious problem: It's authentication is sent across the network as plain-text. Thus, anyone with a packet sniffer or issuing a "man in the middle" attack can obtain confidential information and subvert authentication credentials.
As a result, Telnet's use is diminishing lately. Few Linux distributions ship with it enabled by default and many out-right discourage it with warnings when it is being installed.
If you really have a need for a Telnet server on your system then the most common is telnetd. However, I personally would recommend using it only in chrooted environments.