[NTLUG:Discuss] iptables Firewall for one?

[Bob Byron]

I simply need to prohibit one of my non routeable ip addresses to be prevented
from accessing the internet.  That is, ip address 192.168.1.* can access the
internet, but I want to prevent 192.168.1.75 from being able to access the 
internet.  I have the monmotha iptables package running to create the bridge
between the lan and the internet.  But, I just need the simple iptables command
to insure this person goes no further than inside the local network.

Thanks,
Bob Byron