Ok,

First of all, it is very likely that you do not have a "static" IP for your cable modem, but one that is assigned via the ISP when the modem boots up. I have checked mine a number of times, and it is the same most of the time, but if I shut it down for a day or two, it will be a different IP. The IP is dynamic, assigned as needed. I believe (At least with my ISP) that they manage it thru the MAC address.

I think that if you assign your gateway in the config of your browser, or under network setting, you might be able to hit the internet.

Putting it simply, your gateway needs to know what the modem IP is, the work stations should know what the gateway IP is.

How are the IP's being assigned? Do you have the gateway (I assume you mean router or proxy server) doing DHCP? Are you under Windows? Can you give me more details?

MrCoffee