ANSWER:

Look for port forwarding or port triggering or “NAT” or a similar term in the router interface. Forward port 22 (or whatever you have moved it to if you have moved it) to the IP of your Ubuntu server. You will want to set a static IP for the Ubuntu server.

Once you have the SSH up and running and can be reachable on the outside, you can forward just about any port from the machine you are working on to the Ubuntu server, or anything on the same network with it.

Be aware that some ISP’s tend to juggle IP addresses for regular home users, so you may want to look into something like DynDNS service, or write your own probing script to email you, etc. if your home IP address changes.

by Tim from http://unix.stackexchange.com/questions/39346