Here's my situation: I manage a small (~20 user) network. All on a single subnet attached to a SonicWALL Pro1260. WAN connection is a single T1. From time to time Internet access becomes "slow" (i.e. heavy usage) and this prompts the boss to ask, "WHO is using up the bandwidth?"
Is there a straight forward way to monitor, in real-time, what bandwidth is being used by each IP address on our LAN? (Who's browsing a vendor site, who's downloading an iso, who's streaming video -- you get the idea.)