> > >It is necessary that the wire protocols distinguish between > > >existence and non-existence of resources in a standard manner > > >(NXDOMAIN in this case) in order to give the client the choice of > > >how to handle non-existence. > > [ on dns not the best choice for authoritative non-existence ] it's hard to imagine that there's a better oracle than DNS to ask about the (non-) existence of a DNS name. now to assume that the DNS name is bound to anything in particular, like a host, or a particular business concern, that would be a stretch.