IP address to Domain Name? DNS?

Question

I'm trying to find the authoritative name servers for a given IP address and as far as I can see the only way to find the name servers is by using the domain name of the IP.

1. How do I convert the IP to domain name (not hostname)?
2. Or how do I find the authoritative name servers for any IP address?

Answer 1

You can use dig to get PTR RR, for example:

dig -x 8.8.8.8