you have to go out of here, so you reach the list, there you find the "new topic" button.
when relaunch hfs – it's changing domain (menu>ip adress>custom>domain) to new ip.
i guess you enabled the "find external address at startup". This will also automatically select the new found address.
also isn't it possible to set autochecking of new external ip every n sec?
nope, because it relies on external services, we cannot "bomb" them
by the way would be nice to update more than 1 dyndns.
sorry, that's a basic updater. If you need more power you can install a specific program. There's plenty of them.