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detox1978Flag for United Kingdom of Great Britain and Northern Ireland

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DNS lookup issue

Hi All,

I have built five new servers that need to lookup against two DNS server.  One internal and the other external.

This worked fine for a week or so.  but recently it stops doing external lookups every 12 hours.  To fix it have either do an ipconfig/flushdns or run a repair on the NIC

Any idea how i can check to see what the issue is?
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subhashchy
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have you try rebooting it once
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James
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Do the Event Log report any errors or warnings on either side?

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subhashchy, after rebooting the issue still reoccurs.

JBond2010, the external DNS servers has root hints, there are no forwarders setup.

yo_bee, there is nothing in the event logs to event suggest there is an issue.  If I PING a domains it returns not found.
Internal --> external or vice-versa ?
Also, when the issue is happening i can still do nslookups against the DNS server.
Do you think there may be a corrupt entry somewhere in DNS causing the issue? Do you have scavenaging turned on for stall records?
Have you check the host file on the server or servers to make sure there are no invalid static entries? And are the servers using the correct ip addresses for DNS resolution ie, are the server pointing to themselves locally?
yo_bee,  all the servers have three NICs.  1st External, 2nd Internal, 3rd management/back vLAN.  The order if the DNS on the external NIC is external, internal, external, internal.  The internal NIC has only internal DNS.  And the management/back vLAN has no DNS.

JBond2010, is there a way to check for a corupt entry?  +there are no invalid static entries, could this cause external DNS to stop occurring?  ++Yes the servers are pointing at themself.

Do they have different internal / external FQDN?
Also what is  the purpose of your external dns server?
The external is in a workgroup and internal on the domain.

The Internal DNS server doesn't have root hints, so the external was setup.
Did you apply delegation for the two zones?
The External is in a workgroup so i doubt there is any crossover.

How do i check?

Did you apply delegation for the two zones?
So your workgroup needs to see domain objects?
There has to be some sort of trust for the replication?
There is nothing that replicates.  The external DNS server is only used for lookups
I think I am missing something.
Sorry about this.
The workgroup has a DNS server with it's own subnet?
The domain also has it's own DNS for the domain?
What is your purpose of the dns in the workgroup (for Internet resolution or the internal domain resolution)?
The external DNS is not on its own subnet.   And is the only method for external DNS lookups.  Only the proxy and exchange server use it.
I would try what @JBond2010 suggested and create a forwarder.
Thanks for the tips.  we are setting up forwarding.