How to portforward a public ip address on Linux?

I want to make a minecraft server for use on Linux so people can connect to it by a domain - I have DynDns set up on the system with ddclient but first I need to link my private ip with my public ip, and then through DynDns?

I know the interfaces file has something to so with this. But I only have eth0 and lo? There's no eth1?

isaac

You don't port forward on the computer- you port forward the router to that computers local IP! Go to http://portforward.com and READ about it! There are even step by step guides for you. Basically you are working on the wrong device!

Tracy L