I'm can seem to get the entire DNS reverse ip look up.

Question

I'm trying to get all the domains linked to a record like here http://viewdns.info/reverseip/?host=23.227.38.68&t=1 but I'm getting no luck with dig 23.227.38.68 or nslookup 23.227.38.68. Any idea what I'm doing wrong?

Answer 1

The design of DNS does not support discovering every domain associated with a certain IP address. You may be able to retrieve one or more DNS names associated with the IP address through reverse IP lookup (PTR records), but does not necessarily give you all domains. In fact, it rarely will.

This is because the information you seek is scattered throughout the global DNS network and there is no single authoritative node in the network that has this information. If you think about it, you can point the DNS A record of your own domain to the IP of stackoverflow.com and that's perfectly valid, but anyone seeking to know this would have to find your DNS servers to figure this out. DNS does not provide any pointers for this, though.

Yet, certain "passive DNS" services (probably including viewdns.info) seem to overcome this limitation. These services all work by aggregating DNS data seen in the wild one way or another. At least one of these services works by monitoring DNS traffic passing through major DNS resolvers, building a database from DNS queries. For instance, if someone looks up yourdomain.com that points to 1.2.3.4 and the DNS query happens to pass through the monitored resolver, they take note of that. If a query for anotherdomain.com is seen later and it also resolves to 1.2.3.4, now they have two domains associated with 1.2.3.4, and so on. Note that due to the above, none of the passive DNS services are complete or real-time (they can get pretty close to either, though).