I needed to install Microsoft Network Load Balancing (NLB) on two Active Directory Domain controllers running Windows Server 2008 R2 SP1 to load balance Active Directory Federation Services AD FS 2.0 on TCP443.
Here is the my setup:
Generally the Network Load Balancing Virtual IP Addresses do not get registered in DNS automatically. However I found out that if Network Load Balancing is installed and configured on a DNS server, both the virtual network adaptor address and dedicated network adaptor address get registered in DNS.
For my two domain controllers QV1-DC1 and QV1-DC2 there were two A records for each... the servers IP address and my virtual NLB address. DNS round robin, which is enabled by default on all Windows DNS servers was distributing at random either the servers IP address or the virtual address.
The problem here is the virtual address was only listening on port 443 meaning no Active Directory queries could reach the domain controller for any hosts who resolved the virtual IP address.
I found a fix which allowed me register the IP addresses I want on each of my servers to DNS, instead of turning of dynamic DNS updates all together. This registry key is:
Now my two domain controllers only register their IP address in DNS, not the NLB Virtual IP.
I found the fix on the following KB Article: