TCPView

TCPView, monitors both incoming and outgoing connections, as well as listening applications, in real time. You can use TCPView to identify exactly which servers a client connects to, including the port numbers, or identify the clients connecting to a server.

To download TCPView, visit http://technet.microsoft.com/en-us/sysinternals/bb897437.aspx. You do not need to install TCPView; simply copy the executable file to a folder that allows applications to be run (such as C:\Program Files\) and then double-click Tcpview.exe. TCPView also includes Tcpvcon.exe, a command-line tool that provides similar functionality.