TCP/IP swiss army knife

 A simple Unix utility which reads and writes data across network connections
 using TCP or UDP protocol. It is designed to be a reliable "back-end" tool
 that can be used directly or easily driven by other programs and scripts. At
 the same time it is a feature-rich network debugging and exploration tool,
 since it can create almost any kind of connection you would need and has
 several interesting built-in capabilities.
 .
 This package contains the OpenBSD rewrite of netcat, including support for
 IPv6, proxies, and Unix sockets.