We have an Internet connection which is shared on five computers via a home router.
One of the computers is using torrents all the time. I want to find out which, and they won't tell me.
How can I check which client is using the most traffic?
I recommend reading these articles from HTG:
WallWatcher collects, displays, and analyzes log information from more than 135 Routers and firewalls.
Take a look at Cacti as well.