What is a reverse zone and how do I set one up?

Question

Background: I have a domain registered through register.com and they have a form for me to setup a reverse zone. I also have a VPS at an IPv4 address x.x.x.x.

What I know: PTR/reverse zones are just the opposite of A records.. and instead of mapping a domain name -> ip address it maps an ip address -> domain name.

My problem: The form on register.com for setting up reverse zones/PTR records has a text-input box and then ".arpa" to the right of it. Do I simply enter in the ip address x.x.x.x of my VPS into this form so then I'd have something like x.x.x.x.arpa? Or is there something more complicated that I'm missing? I'm also interested in any resources anyone has that could teach me more about how the DNS system functions and the roles of different DNS records.

Answer 1

For a reverse zone there to be useful, you need to have control of the zone delegated to the servers that you're creating them on.

Essentially, this needs to come from the owner of the IP address; you'll need to ask your VPS provider if they'll delegate control of the reverse lookup for you address to you (or, otherwise, configure the record to what you desire it to be).

The format of the record is to reverse the octet parts of the IP address, in order to fit within the hierarchy structure of DNS. For instance, the reverse lookup for the address 192.0.2.150 is 150.2.0.192.in-addr.arpa.