Hi Fionavar
It looks like you have 2 routers. Probably one supplied by you and one by your ISP.
It also looks like you are trying to GM from more than one computer? Generally this does create issues. You can only port forward a specific port to one computer at one time.
Anyway... log onto 172.16.1.254 and set a port forward rule there to forward tcp 1802 to 172.16.1.65
Im guessing though that 172.16.1.65 is dynamic - you probably want to set a DHCP reservation for your router n the ISP router and set a DHCP reservation for your PC on your Router

