Proc Net Monitor - SecurityXploded is an Infosec Research Organization offering 200+ FREE Security/Password Recovery Tools, latest Research Articles and FREE Training on Reversing/Malware Analysis
TCPView - TCPView is a Windows program that will show you detailed listings of all TCP and UDP endpoints on...
PortsMonitor - PortsMonitor is a system utility for monitoring system TCP/IP network connections by application...
TcpView For Linux - TcpView For Linux. Touch screen friendly design graphical network connections viewer for Linux.
CurrPorts - CurrPorts displays the list of all currently opened TCP/IP and UDP ports on your local computer.
Angry IP Scanner - Open-source and cross-platform network scanner designed to be fast and simple to use