I think I'm being the victim of a bug here. Sometimes while I'm working (I still don't know why), my network traffic goes up to 200 KB/s and stays that way, even tough I'm not doing anything internet-related.

This sometimes happens to me with the CPU usage. When it does, I just run a top command to find out which process is responsible and then kill it. Problem is: I have no way of knowing which process is responsible for my high network usage. Both the resource monitor and the top command only tell me my total network usage, neither of them tells me process specific network info.

Is there another command I can use to find out which process is getting out of hand?

I've already tried killing all the obvious ones (firefox, update-manager, pidgin, etc) with no luck. So far, restarting the machine is the only way I found of getting rid of the issue.

EDIT: (just to be clear) I've found questions here about monitoring total bandwidth usage, but, as I mentioned, that's not what I need.

UPDATE: The command iftop gives results that disagree entirely with the information reported by System Monitor. While the latter claims there's high network traffic, the former claims there's barely 1 KB/s.

Thanks