Disable internet access for non domain clients?

[realized]

I have a problem with people bringing laptops on the network, the problem here is they get an ip/dns/gateway before they login to the domain, so these machines are "open" to internet access but not authorized to be on my network.

What are some ways to disable NON DOMAIN clients from getting on the domain?

the way my network is configured:

Windows 2003 Standard

DNS SERVER (if i can disable dns acccess to non users that might help)

Gateway is ROUTER

DHCP server is the windows 2003 machine.

Please help !!

[chilifrei64]

Your best bet is a proxy server configuration for your gateway.. this way you can set it so they have to authenticate to get out. ISA would be the easiest to set up since it would work with Active Directory pretty easily. Otherwise.. other proxy servers have the capibilities of checking credentials agains RRAS Radius Server