Internal PCs Losing DNS server

Hello all :)

I have a VERY strange problem that has just appeared.

We run a windows AD domain, mix of server 2008 and 2012 with DHCP.

Lately some users are losing access to the internet.

Running a nslookup command returns "server unknown"

Releasing and renewing the IP on that PC fixes that problem for several hours until it happens again.

The DNS server also runs DHCP and is a DC.

I have checked the DHCP settings and they are all correct with regards DNS IP, gateway IP etc.

What could be causing this odd behaviour?

tracyprierNetwork AdministratorAsked:
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are they connected over a wired network?  No wireless adapters (unstable wireless?)?
tracyprierNetwork AdministratorAuthor Commented:
I'm trying to give you some pointers here...

Try to determine if the problem is on networking side, dns, or dhcp.
If you have  the problem, can you do a ping to the ad on ip?  (This could exclude adhcp-ip problem.)
What about the lease time on the dhcp server?
can you ping the gateway?
Did you check the network connectivity (stability) of the DNS=DHCP server? do you have a backup dns-dhcp?
tracyprierNetwork AdministratorAuthor Commented:
Turned out to be a WAP with DHCO enabled.

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