what other ports can you use?

i think your mixing up what a port actuly is. if i was to do a port scan on my router and find that port 80 wasnt up then this means that there is no webserver running it does not mean i cant go to www.google.com which listerns on port 80 it just means theres no web server running on that port.

so if you port scan your gateway and find open ports this does not mean these are the remote ports you should use to connect to other machines or local ports that you should use to connect to other machine it just means theres services runing on them ports