HELP! QUICK! iptbales for a gateway!

[Carl Pender]

Me again, for those of you who might know me. To refresh on the setup that I have and what I want to achieve from it;

WinNT PC ----- LINUX BOX ----- LAN

I am using a PC with SuSe7.3 LINUX as a gateway computer. I've set it up, using "iptables" so the NT PC can access the LAN through the gateway.

What I wish to do is set up the gateway PC so as to able to choose which IP address I will let through the gateway. I want to able "open" the gateway if the IP address is the one I specified and "close" the gateway if it is not. I presume you would use "iptables" to do this but for some reason I can't get it to work.

If anyone could help me with this I would be very greatful, as I am running out of time. Thanking you in advance
Carl

[Radar]

If time is an issue, why not use a pre made script? This one (http://monmotha.mplug.org/firewall/firewall/2.3/rc.firewall-2.3.8-pre7) allows you to enter the values you want in the config section. Theres a url for the help page right in the comments before the actual config section.