Which programs using my internet connection?

My internet connection has 4GB quota. But my quota is run out very fast.

I setup Net Limiter , for look which programs using my internet connection. But there isn't any weird program. There is only firefox.exe .

So, how can i look all programs which using my connection and leech my bandwidth quota?
For example, is there any CMD command ? like netstat

Answer

Try using TCPView from Sysinternals to see if you can get a better view of what's using your network connection.

TCPView is a Windows program that will show you detailed listings of all TCP and UDP endpoints on your system, including the local and remote addresses and state of TCP connections. On Windows Server 2008, Vista, and XP, TCPView also reports the name of the process that owns the endpoint. TCPView provides a more informative and conveniently presented subset of the Netstat program that ships with Windows. The TCPView download includes Tcpvcon, a command-line version with the same functionality.