if you go to dyn-dns.com you can sign up for one free domain name e.g. yourdomain.homeip.net or yourdomain.homelinux.com. This domain name will be mapped out to your ip address each time it changes through either a software client on your server or through your router (mine is a Speedstream router and it had an option in the gui for dyn-dns where you simply enter your dyn-dns username and password) each time your ip address changes the dns entry for it will be updated by the client and you will be able to access the ever changing ip adress from the outside by using the domain name.