Non-AD Integrated Secondary DNS Promote to Master?

Question

Hello. We currently run a non-domain joined 2012 R2 DNS server for our external .com domain. I would like to stand up a secondary in our DR datacenter, but am wondering how I would promote it to master in the event our current master were to fail? Both platforms
are Server 2012 R2.
ns1.domain.com = master
ns2.domain.com = secondary
In the event ns1 experienced a failure, I'd like to be able to promote ns2 to become master (authoritative) for the .com domain to allow record changes.

Answer 1

Hi,
According to your description, my understanding is that primary DNS server has been down, and you want to change the secondary DNS server (not domain member and configured for external name resolution) to primary DNS server.
If there is one DNS server in your domain, I am wondering if it is an AD-Intergraded zone. And if the secondary DNS server has a full transferred secondary zone.
In general, compared the secondary DNS server with primary DNS server, you may find that the secondary one do not have a  folder in forwarder lookup zones named
_msdcs.<domain.com>, according zone transfer we may copy this folder and RRs. But considering the primary DNS server is down, we need to manually copy these date to secondary DNS server.
If the primary zone is not AD-Integrated, open path %systemroot%\system32\dns\
on primary DNS server and copy the file _msdcs.domain.com.dns/domain.com.dns
to the corresponding path on secondary DNS server, then create primary zone using this exiting file. All RRs will be displayed once the zone has been created. 
For AD-Integrated primary zone, we need to back up the zone by command lines and then restore it to the secondary DNS server, detailed steps you may reference:
https://technet.microsoft.com/en-us/library/jj649877.aspx
https://technet.microsoft.com/zh-cn/library/ff807395(v=ws.10).aspx
Or you may also try to manually add the folder _msdcs.domain.com.dns, including its sub folders and RRs. And remember to change the secondary zone type to primary.
And remember to redirect DNS clients to use the secondary DNS server as the primary one.
Best Regards,
Eve Wang
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