Telnet is a network protocol and a network application that provides bidirectional interactive text-oriented communication between two endpoints. One endpoint acts as a server and another acts as a client. You can use Telnet client on Mac OS X by running telnet command in the Terminal followed by ip address or domain name of the server:
anand$ telnet localhost
However, if you need to make your Mac OS X (Mavericks) to run as a Telnet server you can enable it from the Terminal via launchctl command. You can follow the following steps:
anand$ sudo launchctl Password: launchd% load -F /System/Library/LaunchDaemons/telnet.plist launchd% exit
Now you can try using Telnet client to your Mac. For example, you can use telnet command on the Terminal to access the Telnet server on your Mac:
anand$ telnet localhost Trying ::1... Connected to localhost. Escape character is '^]'. login:
Now you can provide log in information to gain access to your Mac via Telnet!!.
Note that Telnet is a plain text-based application without any encryption and it is not secure. You may want to use SSH instead if you want to do remote management of your Mac.
This technique should also work with Mac OS X Lion as stated in this post