[derefr]

Crazily enough, this is built into most DNS implementations. It's called Hesiod-class records: http://en.wikipedia.org/wiki/Hesiod_(name_service)

If you've ever wondered why DNS requires the "IN" (for "Internet") in all its record declarations, it's to make this distinction. The other two options are "HE" (for Hesiod), and "CH", for http://en.wikipedia.org/wiki/Chaosnet.