Steps to avoid registering unwanted NICs in DNS on a mulithomed domain controller
This article provides a solution to an issue where unwanted network interface controllers (NICs) are registered in Domain Name System (DNS) on a mulithomed domain controller (DC).
Original product version: Windows Server 2012 R2
Original KB number: 2023004
On Domain Controllers with more than one NIC where each NIC is connected to separate Network, there's a possibility that the Host A DNS registration can occur for unwanted NICs.
If the client queries for DC's DNS records and gets an unwanted record or the record of a different network that is not reachable to client, the client will fail to contact the DC causing authentication and many other issues.
The DNS server will respond to the query in a round robin fashion if the DC has multiple NICs registered in DNS. The DNS will serve the client with all the records available for that DC.
To prevent this issue, we need to make sure the unwanted NIC address is not registered in DNS.
Below are the services that are responsible for Host A record registration on a DC:
- Netlogon service
- DNS server service (if the DC is running DNS server service)
- DHCP client or DNS client (2003/2008)
If the NIC card is configured to register the connection address in DNS, then the DHCP/DNS client service will register the record in DNS. Unwanted NIC should be configured not to register the connection address in DNS.
If the DC is running DNS server service, then the DNS service will register the interface Host A record that it has set to listen on. The Zone properties, the Name server tab list out the IP addresses of interfaces present on the DC. If it has listed both the IPs, then DNS server will register Host A record for both the IP addresses.
We need to make sure only the required interface listens for DNS and the zone properties, name server tab has required IP address information.
To avoid this problem, perform the following three steps (It's important that you follow all the steps to avoid the issue).
Under Network Connections Properties:
On the unwanted NIC TCP/IP Properties, select Advanced > DNS, and then unselect Register this connections Address in DNS.
Open the DNS server console, highlight the server on the left pane, and then select Action > Properties. On the Interfaces tab, select listen on only the following IP addresses. Remove unwanted IP address from the list.
On the Zone properties, select Name server tab. Along with FQDN of the DC, you will see the IP address associated with the DC. Remove unwanted IP address if it's listed.
After doing this, delete the existing unwanted Host A record of the DC.
Hardware details: IBM servers with two NICs.
- Ethernet NIC
- USB NIC (it also can be considered for multiple Ethernet NICs)