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I have pointed an external website to a new IP address.

When I query the domain from an non-networked computer or device it picks up the change.

I've run dnscmd /clearcache on both DCs several times now and they keep getting the old IP.

There is nothing overriding the external IP on the DNS servers (no zones with the same domain name as the one I'm trying to update.

If I query the same external dns server that my DCs use for forwarding, for the url on a non-networked device I get the new IP. So the external DNS server has picked up the change.. but my DCs seem to be stuck with the old ip even after clearing the cache.

Edit: On further investigation (nslookup thedomain. externaldnsserver) the external DNS server is still serving the old ip address to my DC... but it serves the new IP address to other devices. I guess the problem (if it is a problem and not 'design') is on their DNS server.

Edit 2: The external DNS server in question is now returning the new ip. I will leave this question undeleted in case there is any value in it being left... unless anyone disagrees?

MrVimes
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1 Answers1

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nslookup.exe -type=SOA TheDomain ExternalDnsServer

How long is the nameserver set to hold onto records (see the "refresh" field of the SOA record)?

nslookup.exe -type=A -debug TheDomain ExternalDNSServer

How long is the nameserver instructing clients to hold onto responses (see the "ttl" deliver with each record)?

DTK
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  • The `SOA` `REFRESH` field tell servers hosting slave zones how often they should check if the zone has changed on the master (as kind of a baseline in addition to the notify messages normally sent by the master). – Håkan Lindqvist Nov 29 '14 at 14:42
  • refresh - 1 day There is no ttl when I run with -type=A But the thing is... if the external dns is set to hold onto the record for one day, why are external machines able to get the new ip from that dns server? And if I've cleared the cache on my internal dns servers they are no longer 'holding onto' anything. – MrVimes Nov 29 '14 at 14:43
  • You need to to turn on debugging to see the TTL. – DTK Nov 29 '14 at 15:46