Sir ,

I have one RETHAT AS4 server for internet. Around 300 hundred systems with win XP for different peoples. The owner of the systems knows the administrator password of their system. All peoples are in the network.

For accesing internet i gave gateway i.e server ip and DNS of ISP along with system ip and subnet as usual.

Among 300 people I want to give only 15 systems want to connect internet. For others even if they have entered gateway address and dns in the network settings , they could not able access.

Strictly speaking, what ever ips i entered using iptable , that systems only could connect internet others could not.

So may softwares available like squid but i need simple iptable rules.
How to make rules easily?

Experts can easily understand my request and i hope i can get quick response

Thanking u