Any way to moniter bandwidth speed

I am a network admin and someone on my network is using tons of bandwidth. No one is owning up to it so I was wondering if there is a tool I could use to see where it is all going.

 

Wireshark (Formerly Ethereal) 0.99.5 is a free network protocol analyzer (TCP/IP Sniffer)

There are many commercial bandwith shapers and network monitors around but for use in a commercial environment you will probably have to pay.

A commonly used monitor is Websense

What operating system are you running ? You should probably block commonly used p2p ports on your router or server too.

 

I am not worried about P2P but I did do that already. I have a few people that like to listen to the radio online and KILL everyone's bandwidth but no one will fess up to it. I am to the point of getting ready to take everyone's speakers away.