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Just to give a context of the problem.

  • I have a vps in A with debian and a static IP
  • I have a domain allocated in a registrar B

After talk to my registrar I have these free dns: 

dns1.host-redirect.com
dns2.host-redirect.com
dns3.host-redirect.com

Now, my question is: what I need to change in my VPS in A to resolve my static IP to the domain in B?

Fel
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  • Um... talk to the ISP that provides you with the VPS? Reverse DNS has nothing to do with forward DNS except for the infrastructure used. https://en.wikipedia.org/wiki/Reverse_DNS_lookup#IPv4_reverse_resolution – user Jul 04 '16 at 10:51
  • @MichaelKjörling sorry, but I am completely new about about this stuff. What is the utility of the dns provided by registrar? How do you know that dns is a reverse DNS? Can you please elaborate an explanation of what I need to configure and request? – Fel Jul 04 '16 at 11:01
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    You just create the host record on the DNS B matching your IP ? DNS replication will bring the info to A, iam missing something? – yagmoth555 Jul 04 '16 at 11:15

1 Answers1

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The IP address (I'll call it just one here, but the concept applies equally well with any number of addresses) which is assigned to the VPS is assigned to the ISP where the VPS is running.

In forward DNS, you register a domain name, have it pointed at your name servers, and configure those name servers to serve that zone.

In reverse DNS, the owner of the IP block receive a delegation for the appropriate zone under either in-addr.arpa or ip6.arpa. In the case of a reasonably-sized block they can delegate this further to your name servers in a manner described in RFC 2317, Classless IN-ADDR.ARPA delegation. If you have only one or a few IP addresses, they may be unwilling to do so because of the overhead involved.

Just like there is no way to query the DNS network for "all host names that have an A record pointing to 192.0.2.1", there is no way to query the DNS network for "all records that have a PTR record pointing to myhost.example.com". Instead, the owner of the netblock 192.0.2.0/24 would need to add a record like 1.2.0.192.in-addr.arpa. PTR myhost.example.com. (or equivalent, in case of RFC 2317 style delegation). As you can see, this is nowhere near example.com in the DNS hierarchy.

So you have two options, really:

  • Ask the ISP that runs your VPS to create a PTR record for the IP address in question, with the host name you want the VPS to be known by. This is the easiest in the short term.
  • Ask the ISP that runs your VPS to delegate the appropriate netblock to a separate RFC 2317 zone and delegate that zone to DNS servers under your control, where you can add a PTR record yourself. This requires more initial configuration from the ISP, but shifts the burden of administration onto you for the future.

Note that in each case, the ISP that runs the VPS must make some change. Your domain name and domain name registrar (unless the latter just happens to be the company that also runs the VPS) has nothing to do with this per se.

Community
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user
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  • I set in registrar a new rule with type A and pointing to IP. And this works fine when I type the domain in browser, as suggested by @yagmoth555. So, why I need a PTR record? – Fel Jul 04 '16 at 12:11
  • @Fel "resolve my static IP to the domain in B" implies reverse DNS. It is not the same thing as "resolve the domain in B to my static IP" which would imply forward DNS. If you feel it doesn't, then IMO the question is unclear. – user Jul 04 '16 at 12:19