Network monitoring tools?

[Tarmael]

I've been looking for a multipurpose, cross-platform network monitoring program.

A mate of mine suggested WireShark, so I thought I'd nab that, and ask you lot.

2 things:

1. What works for you?

2. Can you advise me to one that can monitor the difference between network traffic and internet traffic?

My reasoning for this:

I live with my Fiance and her parents, I'm a net rat, and they blame me for the person who reaches the bandwidth cap, I need proof that it's actually my Fiance's brother.

Cheers.

Bas.

[Tarmael]

So no one has anything to say about network monitors?

[df6269]

Here you are
http://www.cacti.net/

[Junglizer]

Wireshark is probably the way to roll.

[dentaku65]

What about tcpdump?

[Tarmael]

I think I need help with Wireshark...

It looks as though it has everything I need and then some, but I'm not too sure how to make it work the way I want it.

Also, I'd like a program that starts up with everything else, and just sits in the background.