Internal Clients not resolving to internal Ip

Hi Team,
We have a standard domain network running server 2012.

now the problem is as follows
Any internal client when they ping is supposed to resolves to

Now what happens sometimes is that every morning when someone turns their PC on they might get an issue where out of blue the DNS starts to resolve to the WAN IP of our network

If i flush the DNS the issue is resolved

Has any one faced a similar issue.

And the strange part of that it happens even to the machines that were left in the office overnight s well and not only to the ones that were out of the office.

All clients get IP from DHCP server
and gives out DNS' as and

Any ideas?
Costas GeorgiouNetwork AdministratorAsked:
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Do the PC's ave wireless NICs that are connecting to an external network?

Have you checked your internal DNS to see if there are multiple entries for
A lot of times this will happen when your DNS server does not respond in a normal amount of time to a request.  The client can not resolve the internal IP and so looks to the root hints and gains the External IP.  By the time you get to the computer in question .... DNS works again on your server.. but the local cache already has the external IP. So when you clear the cache, all is well.

Also .. this can happen if there is an external IP address added to the IP configuration for DNS servers as a backup.

Also .. if you have split routes to the destination, and one goes down .. then you do not see the route to the internal IP address and are sent to the external.

I would start with DNS performace and work out from there to narrow it down.

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Faruk Onder YerliOwnerCommented:
Could you please check DNS viruses in your computer.?

one of them you can check as below.
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Costas GeorgiouNetwork AdministratorAuthor Commented:

Thanks for your response guys

I also started from the DNS forwarders and then yesterday i already removed all the DNS forwarders from the server.
But this morning got the same issue

I think its the way the DNS is working right now.
There are some machines that even after flush DNS still resolve to teh WAN IP
Costas GeorgiouNetwork AdministratorAuthor Commented:
I have two DNS servers and i have made some change to the primary and secondary zones and shall get back to you with an update.
When you are having the issue ... pull up a command prompt on the client and type nslookup ... does it list your internal DNS server?

Is your internal namespace or abc.local (or something else)?
Costas GeorgiouNetwork AdministratorAuthor Commented:
I have two DNS servers and i have made some change to the primary and secondary zones and shall get back to you with an update.
@ stu29
Nslookup shows the right server and have added a PR records for the DNS server as well which was missing

Costas GeorgiouNetwork AdministratorAuthor Commented:
Thanks for the response guys

The issue has been resolved

@ stu29 : thanks for the hints they were in the right direction

And also thanks to others participating

Solution: The issue was with DNS zone and name servers for the secondary zone.
ConnectCG .. glad you working it out!
Costas GeorgiouNetwork AdministratorAuthor Commented:
We were able to resolve the issue , however the team did provide information relevant to the issue and in the right direction.
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Windows Server 2012

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