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Our reverse DNS lookup is delegated to our name server (ns.example1.com) by AT&T, who leases us our IP address (1.2.3.4) and our forward DNS lookups were on the same name server (ns.example1.com).

Previously rDNS lookups for abc.example0.com were successful
i.e. host 1.2.3.4 correctly returned a pointer to abc.example0.com

The forward looking DNS has been moved to ns.example3.com but the rDNS is still delegated to ns.example1.com

Our rDNS lookups are now failing. To the best of my knowledge the AT&T delegation has not changed and

host 1.2.3.4 returns not found: 3(NXDOMAIN)

host 1.2.3.4 ns.example1.com correctly returns a pointer to abc.example0.com

Do the delegated rDNS and forward DNS both need to be served from the same name server? (currently they are ns.example1.com and ns.example3.com respectively)

Sal Ferrarello
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    Telling us the ip address and domain name would be helpful in determining what and where the problem is. This isn't "confidential" or "proprietary" information and you're not "exposing" anything by providing us this information. If you didn't want people to find this information you wouldn't have a publicly registered domain name and would have no need of a rDNS zone, so please help us to help you by giving us the "real" names and ip addresses. – joeqwerty Jul 15 '13 at 18:34
  • Having the real IPs and hostname would help us troubleshoot, but to answer the question you asked, no they do not need to be served from the same name server. They are entirely different zones. –  Jul 15 '13 at 18:43
  • Thank you both for your comments confirming rDNS and DNS do not need to be on the same server. I agree it would make sense to share the hostnames and IPs with you but unfortunately it is not my call to make. Thank you. – Sal Ferrarello Jul 15 '13 at 21:14

1 Answers1

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It is common for the reverse and forward DNS records to be on different DNS servers.

Whoever provides the IP address will maintain the PTR record for on their DNS servers. The domain registrar will maintain the DNS for the domain. Either of these can delegate the records to another server.

If a delegated domain is migrated, it is important to ensure the delegating domain is notified to update the glue records. Until they upgrade their records, DNS lookups will fail when they try to used the old addresses. In this case, it appears you need to notify the IP provider to update the NS records for your IP address block.

BillThor
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