DNS Not Working Properly After Mulithomed DC Change

After adding a secondary NIC to a Windows Server 2016 DC I went back to remove the secondary NIC from DNS. It had already registered itself with DNS and I only want the server to listen on one NIC for DNS requests.

I followed this procedure from MS to attempt to resolve the issue.

1. I unchecked Register this connection in the NIC DNS Advanced Settings.
2. I set the DNS server to only listen for requests on the correct NIC.
3. I removed all the secondary NIC Host (A) records from the Zone under the Domain Name, as well as the additional records that were located in the DomainDNS and ForestDNS Zones. There were no Reverse Lookup records for the secondary NIC.

I then flushed the cache and registered the cache. I even ran DCDIAG /fix and restarted the server.

When I do a simple or recursive query from the Monitoring tab the test fails. Also, when I ping the server either by servername or servername., or by FQDN, I get the IP address of the secondary NIC. However, NSLookup returns the correct information.

The only way I can get the simple or recursive test to pass or get the correct IP from a ping is to disable the secondary NIC.

I must be missing a setting somewhere as it seems the secondary NIC info is stuck and I can't remove it. I have tried this procedure multiple times, the only way to get the DNS queries to pass again with the secondary NIC enabled, is to restore the secondary NIC to the DNS server records.

The primary NIC address is 192.168.0.x The secondary NIC address is 192.168.1.x

The secondary NIC has no GW and the preferred DNS is set to the IP of the primary NIC.

Thanks for any advice.

Try the following.

Check NIC binding order. Run ncpa.cpl to launch Control Panel adapters page and then press Alt, in menu select Advanced > Advanced Networking

• If first NIC is not your primary NIC, then set the first one as primary
• complete steps mentioned in MS document page you used before
• restart the server

Stick to the plan and don't do anything else, like running DNS registration before the restart, etc.

I must be missing a setting somewhere.

The information is cached. On clients and the other DC's/DNS servers. There is also the PublishAddresses setting, that determines the single IP address are published for the domain controller in DNS.

https://learn.microsoft.com/en-us/troubleshoot/windows-server/networking/a-record-registered-host-dns

Key: HKLM\SYSTEM\CurrentControlSet\Services\DNS\Parameters
Value: PublishAddresses
Value type: REG_SZ