I usually port forward using Port Map.
I want to port forward ALL my ports, though, which is rather awful to do one by one (same goes for via Airport Utility).
So would there be a way I could forward all my ports at once?
If you have an Apple router then in Airport Utility you can go to:
Network > Network Options button
Then check the box "Enable default host at" and enter your computers IP address.
If you don't have an Apple router then you'll need to go onto the routers web interface and look for a similar option, which may be called something like default host or dmz host.