Ethereal - sniff ALL traffic
I have been playing with Ethereal on our company network, (it's what sysadmin does when b0red), but I can't get it to monitor all traffic - it only seems to pick up frames sent from, or directly TO the LOCAL network interface (ethX). I was of the impression that with CSMA, (ie ethernet-ness), all packets and frames on the network bus could be sniffed.
Perhaps it's just an options with Ethereal that has to be set.. of if anyone knows how to do it using tcpdump, I could probably work it out from there. It would be extremely useful for us to be able to monitor all traffic on some of our more secure areas.