Go to to the dyndns site and sign up for a dyndns name - basically a static name is tied to an ip address that will be updated with the dhcp address when the router address changes, pretty infrequently anyway.
Go to router admin advanced and select Personal Domain Name
enter the dyndns name you created under host name
select broadband ethernet
select dyndns.org
enter the dyndns userid you created
enter the dyndns password you created
say OK
That's it
If you want to access your router externally in the future use the dyndns name that you created with any associated port needed.
Anytime the router ip address changes the dyndns client on the router will send the new ip address to the dydns server which will update your dyndns name pointer record.
If you don't trust the router to do it then you can add a client to an internal machine instead or in addition.
