How to monitor workstation network traffic

From:	Nathan Harris <nharris at eoimaging dot com>
To:	m0n0wall at lists dot m0n0 dot ch
Subject:	How to monitor workstation network traffic
Date:	Tue, 31 Jan 2006 11:52:24 -0500

I need to monitor the network traffic through my m0n0wall from LAN->WAN 
on a workstation by workstation basis.  It would be great to have a 
graphical breakdown by LAN IP over time (RRDTool, MRTG, etc..).  
However, what I really need is a real time tool to track down which 
workstation is consuming WAN resources.

Does anyone know of a solution for this?

Thanks,

-Nathan