Re: Resolving IP addresses
There are 2 parts of DNS involved here, the normal "A" record which turns a hostname into an IP address, and the rDNS (reverse DNS) "PTR" record which turns an IP address back into a hostname. Many hostnames may point to the same IP address, but the IP address can only resolve back to one hostname.
Take Google's public DNS for example:
The rDNS record is set by whoever owns your server's IP block. Usually you have to go through your ISP or hosting provider to change it. Some hosting providers give you a place in their control panel where you can set the rDNS without needing to contact anyone.
EDIT: also, not all IPs have an rDNS record.
|