U.S. Robotics 9003 SureConnect ADSL Ethernet/USB Router - Port Range Mapping
I recently purchased one of these as I wanted a decent router and firewall, without the hassle of constantly updating my Linux box that I was previously using as a router and firewall.
I've been very happy with the router, but the documentation is pretty poor and if I hadn't previously setup IP masquerading I think may have had some problems, as it was everything was straight forward, apart from getting port forwarding to work ok.
I couldn't find the answer on the net, so as soon as I figured it out I decided that I would post the solution just in case anyone was having problems.
The solution:
1. Go Firewall > NAT > Port Range Mapping
2. Go Firewall > IP Filtering
I hope this helps if you were having problems. If not feel free to mail me.