I have 3 DNS servers in my environment that I'd like to show up on my end users machines for backup. 2 onsite and 1 in Azure. I have a site 2 site VPN connection between HQ and Azure. When I go to check the NIC properties I only see the 2 that are onsite. Also when I check the DNS name server properties for the domain, I see all 3 servers listed on each DNS server. Why wouldn't the 3rd DNS server show up in the properties of the nic like the other 2? I could add it manually from the advanced menu of the TCP/IP settings. But I don't think I should have to. What am I missing? I was looking into the NRPT feature in group policy and noticed there's a generic DNS server option. If that's configured, would that help me acheive my goal, or it's overkill?
Why wouldn't the 3rd DNS server show up in the properties of the nic like the other 2? I could add it manually from the advanced menu of the TCP/IP settings. But I don't think I should have to.
Well... the client TCP/IP settings don't know that you have a third DNS server unless you tell them that you do. You do that by either statically assigning the third DNS server or by assigning it via DHCP. If you're using DHCP then add the third DNS server to your DHCP client options.
Additionally, you'll only see the Primary and Secondary DNS servers on the general properties page for TCP/IPv4. If you want to see the third (or more) DNS servers then you need to look at the advanced TCP/IP settings or use a command prompt or Powershell.