Domain – MX records not correctly updated by the Google DNS servers

domaindomain-name-systememailgooglemx-record

We are currently losing some e-mail and we discovered that this is caused by a wrong DNS setting. We used a CNAME for our MX record an thats not allowed. So about 2 weeks ago we changed it to an A-record to fix the problem.

It seems all major DNS services (like OpenDNS and ISPs) have synced their records and are returning correct results on our DNS queries. But Googles DNS service (at 8.8.8.8) is still returning the CNAME values and we still some e-mails are not delivered correctly.

Query on OpenDNS:

; <<>> DiG 9.7.3-P3 <<>> mx wrep.nl @208.67.222.222
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 51231
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;wrep.nl.           IN  MX

;; ANSWER SECTION:
wrep.nl.        3595    IN  MX  10 druif.wrep.nl.

;; Query time: 21 msec
;; SERVER: 208.67.222.222#53(208.67.222.222)
;; WHEN: Fri Nov 25 21:36:58 2011
;; MSG SIZE  rcvd: 47

Query on Google DNS:

; <<>> DiG 9.7.3-P3 <<>> mx wrep.nl @8.8.8.8
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 12124
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 0

;; QUESTION SECTION:
;wrep.nl.           IN  MX

;; ANSWER SECTION:
wrep.nl.        2372    IN  CNAME   druif.wrep.nl.

;; AUTHORITY SECTION:
wrep.nl.        572 IN  SOA ns0.freshdns.nl. hostmaster.twilightinc.nl. 2011112401 14400 3600 604800 3600

;; Query time: 94 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Fri Nov 25 21:38:10 2011
;; MSG SIZE  rcvd: 117

So is there anyone who can explain why Google is responding with a different (incorrect) result two weeks after the last change? And how can we get Google to update their DNS records correctly? Any help is very appreciated.

(Please note that other domains that are managed by the same DNS servers/tools are working fine.)

Best Answer

I found someone with the same problem I had on the Google public DNS Google Group. The comment from Alex Nizhner helped me solve my problem.

It seems that if you first resolve wrep.nl and this turns out to be a CNAME to druif.wrep.nl the DNS client will cache this. If then you try to resolve the MX record for wrep.nl it will respond with the cached CNAME record and will not return the correct MX record.

So I changed wrep.nl to an A-record waited for all DNS servers to get in sync and everything is working as expected now. All mail is coming through. :)

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