Dynamic local dns changer.

You probably know of ddns services that allow the dynamic change of a (sub) hostname. to point a webaddress to a changing web ip address. This is kinda the same but then for local system. But there is DNS/DHCP (and a lot of other local systems) i hear you say that always point to the right ip. Well your not wrong but there are two use cases that are not capable with dns/dhcp and other local systems