How can i tell which processes are using my bandwidth?

I just installed a freeware bandwidth meter and I see that about 70kb/min are being sent even when I have no programs open on my desktop. I have no p2p programs running. Can someone recommend a freeware program that can tell me which processes are doing the sending?

If you’re using a firewall you should be able to see which programs are accessing the net and how much data they’re sending and receiving. I use the Comodo free firewall ; on the Activity tab it will list programs active, bytes in, bytes out, etc.

This isn’t really for the layman, but it may be interesting even if you don’t understand everything it’s telling you: TCPView is free from microsoft and will correlate open socket connections with processes in a continuously-updating display. (ok, not truly continuously, but every second or so, task manager style).

Note that TCPView only works for connections over a TCP socket. Anything using UDP, ICMP, or some other protocol will not show up. Most programs do use TCP though so it’s worth a shot. There’s probably something similar to the unix program Ethereal which works with all IP protocols.

Wireshark. Can be complicated for newbies, but useful. It helped me track down and eliminate a problem I had with my home theatre software constantly wasting bandwidth by downloading unwanted movie trailers.

Ethereal is available for Windows.

Ethereal is no longer under active development. Wireshark is a Ethereal fork that is being actively developed.

It does show UDP sockets, but being connectionless, it shows a lot less info about them. It’s still probably interesting to know what programs have UDP sockets open.