[clug] Tracking network usage

[Neill Cox]

I have a home network with a number of untrusted clients (ie teenage children
who last month chewed through 80% of my bandwidth allocation in 50% of the month).

In order to avoid having *my* usage throttled by my ISP I want to more closely
monitor the usage by individuals.

For some of the machines this is easy as they are only used by one person.  For
others several different people log on and it's harder to associate traffic with
a particular person.

I'm wondering if there is any way to associate a DHCP request with a
username/password, ie make people authenticate before handing them a DHCP lease.

Just to make it more fun my network has Linux, Mac and Windows clients.

I'm running a Debian based firewall (configured using shorewall) and a squid
proxy, so I can track web usage now, but it's all the p2p and games that are harder.

I have googled and I get the impression that some universities are doing
something similar, but I don't know enough to zero in on any useful information.

Any pointers/cluebats gratefully received.

Cheers,
Neill