How do I check what processes are actively using the network?

Question

Possible Duplicate:
Monitor all and any internet traffic from my home PC - what should I use?

Recently, I discovered that something is downloading on my computer even if I doesn't do anything with it.

Is there any program that can check what process or application that is using the network?

Answer 1

There are many network monitors, I use TCPView, you can see how many connections each program has opened and how many bytes are transferred.

Answer 2

Use a packet sniffer like Wireshark.

Answer 3

I found one called Net Limiter witch was very simple and powerful. Thanks for your help anyway. :)