For those who may not be familiar, a wonderful network administration tool was unveiled in 1995; it was called Netcat. This had a variety of uses, from file transfers, to network monitoring, to chat servers—even so functional as to create a backdoor—by mirroring its input to a specified network address of the user's choice. Netcat was in many ways a very lightweight port scanner—by using a quick shell script, it was extremely easy to check whether certain ports were responding on a given host.

Netcat is still in heavy use today, but the Nmap development team saw some pretty serious improvements—both in stability and usability—that they can make to the software. As such, in 2009, Ncat was released as a part of the Nmap suite.

Unlike Netcat, Ncat has SSL support (natively), great connection redirection reliability, and several other built-in features that make it a great tool in a security administrator's toolbox.

Ncat has two modes: the "listen" mode, which...