I had a problem with my old router a few months ago, got a replacement that mostly works perfect, but I don't seem to be forwarding ports. Maybe I'm just making a mistake, but nothing I've tried seems to work. I'm pretty sure I've associated the correct ports to my computer, but I always have trouble with games that need the correct ports opened. I just turn on DMZ for as long as I need it open and then close it afterwards, but I'd really prefer to just have my ports working properly. For example, GGPO with and without DMZ switched on shows how much trouble I have connecting to other users (I barely get any connections if DMZ isn't on). Any ideas?
If you change the port mapping to be LOGGED you will see inbound connections being routed to your PC in the router logs. That would be a useful diagnostic to confirm that connection requests are being seen and correctly routed. Check the target IP address is correct. Also is the target PC set to have a static address. I have seen incidences of port forwarding being all set up correctly, but the pc's address allocation had changed and things stopped working.