Tool for monitoring bandwith uses
I am in the process of writing something specific as I couldn't find anything I wanted. I needed to capture data whilst logged off.
Net Data Developer
DUMeter unfortunately only shows you what's happening to your machine. I guess the original poster is looking for a tool that tells him which of his users is listening to a portugese internet radio while downloading movies off Kazaa and sucking up all the bandwidth.
There are lots out there. You might want to put a server (running a free os like Linux or BSD) between your uplink and your firewall running ntop. I have seen some people use it with some success. Some of these are kinda faulty though, because they misreport protocols and what not, and if you don't upgrade (usually they are free upgrades, we are talking open source here) you'll miss out on the latest and greatest "in" protocols.
Also watchout for ethereal.. if you know how to make real good use of it you probably can afford something really expensive.
There are modPerl modules that can be used as a proxy to limit/monitor bandwidth. Also, OpenBSD's packet filter PF can do this
You need a protocol analyzer: http://www.wildpackets.com
Beware your switch!
Some network traffic analysers can sniff on a switched network by using arp poisioning.
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