don't buy anything from belkin oh my fucking fuck

do you mean static ip?

i mean set the ip as static on your pc, forget dhcp lease time, it's irrelevant if you have a static ip and add that ip to the dmz in the router. then you can turn on the firewall. after that pass whatever ports you want to that ip. if you don't have upnp working (could be broken or bugged in that version of firmware) ports be forwarded properly.