On Mon, Apr 18, 2011 at 12:10:31PM +0200, Alessandro Baggi wrote: > Hi list. I'm making a program that maps some ip address to a specified > dns. My problem is relative to CNAME record. : > Supposing that I have 209.85.148.104 ip, is possible (only knowing the > ip) go back to the CNAME record www.google.it? > : > > Could someone point me in the right direction?
It is as far as I know impossible. A PTR record points to the canonical name. One host can have several IP addresses but every IP address can hence only have one canonical name. A CNAME record is supposed to resolve to a canonical name, but often enough there is one or more extra indirections before you reach it. There can be CNAME records in any domain so you can not find all resolving to a given canonical name unless searching the _whole_ DNS. > > Thanks in advance -- / Raimo Niskanen, Erlang/OTP, Ericsson AB
