Port forwarding

Hey there…

Got a Netware 5.1 network. Trying to use an SMC Barricade Cable router with a cable modem. I am opening ports for Web Access (7205 and 80) and am not able to connect externally. Internally I am fine. What am I missing?

Also…if port 80 needs to be open on the Web Access server…what happens with my NT IIS web server if it is also on port 80?
Help…please…