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I have an inexplicable issue with DNS for a domain and a subdomain. I first noticed that doing an A record lookup on the subdomain is returning different results than what is in the DNS config. Then I looked further and have found that the DNS for sub.domain.com is resolving from a completely different set of nameservers than domain.com.

For example, when I do a DNS lookup using mxtoolbox, it is clearly displaying that the sub.domain.com is reporting from different nameservers. As far as I knew, that should be impossible since you can only set the nameservers for the top level domain.

I have already tried breaking my local cache with no results. I've also tried clearing the OpenDNS cache but it continues to resolve to the old, incorrect records. The TTL for the record is 2 hours.

andrewvnice
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1 Answers1

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You have NS records for ap defined in your internet facing kuverapartners.com. zone. You are delegating authority away from your nameservers and this is normal behavior.

$ dig +norecurse @ns1.milodigital.net ap.kuverapartners.com

; <<>> DiG 9.8.2 <<>> +norecurse @ns1.milodigital.net ap.kuverapartners.com
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 34676
;; flags: qr; QUERY: 1, ANSWER: 0, AUTHORITY: 3, ADDITIONAL: 0

;; QUESTION SECTION:
;ap.kuverapartners.com.         IN      A

;; AUTHORITY SECTION:
ap.kuverapartners.com.  3600    IN      NS      ns1.cloudworks.com.
ap.kuverapartners.com.  3600    IN      NS      ns2.cloudworks.com.
ap.kuverapartners.com.  3600    IN      NS      ns3.cloudworks.com.

;; Query time: 19 msec
;; SERVER: 208.94.148.2#53(208.94.148.2)
;; WHEN: Mon Dec  8 16:13:23 2014
;; MSG SIZE  rcvd: 104

When a NS record is beneath the apex (top) of your zone is encountered, this is called a zone cut. All records defined on your server behind the cut are effectively "masked", with the exception of glue records. Your nameserver cannot serve responses for those records because it does not consider itself authoritative for them. Only the other server can provide the answers at that point.

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Andrew B
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