... what hosts to list??? (ie: ad2, ad3 ... to ad<x>???)
Been fixing that for a good 6 years now. Just setup your local name servers to be authoritative for doubleclick.net and don't put any A records in the file. Works like a charm. ;-)
on the one hand, you'd need a wildcard A RR at *.doubleclick.net to achieve this result. the above text does not mention this, and leads one to believe that an apex A RR at doubleclick.net would have an effect. on the other hand, if you do this for a nameserver that your customers depend on, then there is probably some liability for either trademark infringement, tortious interference with prospective economic advantage, and the gods alone know what else. if you do this, keep it to a server you run on 127.0.0.1 and ensure that you are its only user. -- Paul Vixie