ubuntu 10.04 server+oscam 1.20 port settings

hello guys nedd a bit of help setting up my port forwarding properly read a few different guides and cant decide on which one is right.
i can connect on my local network to my server and everything works fine i have set up a no-ip account and this is auto updated via my router[bt hh3] which says all is fine i have forwarded port in router settings to match the port i specifyed in oscam but when i try check if its open on another pc not on my network i get port closed message just want to know if theres any other things i can try ive read a few horror stories about bts fibreoptic and homehub3 and getting ports to forward. thanks

Thanks for the suggestions got it sorted I forgot to add the internal ip of the machine I wanted the ports forwarding to