port forwarding question

Hi.

After reading documentation it's still unclear - when I setup port forwarding from external to internal or trusted network, do I have to add corresponding ports into zones?

I mean if I have following rule in my 'external' zone: forward-ports: port=2202:proto=tcp:toport=22:toaddr=192.168.2.2

Do I need to add port 2202 to some zone? Port 22? Or will forwarding in itself is enough?

cheers, Max.