Multiple master servers for the same zones

[Fred Morris]

On Tue, 5 Sep 2023, Leroy Tennison via bind-users wrote:
> 
> After some recent upgrading it was discovered that both DNS servers were 
> configured as master.  I'm assuming i can use 
> https://kb.isc.org/docs/managing-manual-multi-master to "demote" one of 
> them but is there anything to look for concerning possible 
> inconsistencies and how do I check for those issues?

Before you do anything, back up both zone files!

Merge and deconflict any differences. Set the "true" master to a higher 
serial number. Disable zone updates on the secondary.

Pause for a scream test.

Then "the usual" applies: set one of them to be a secondary and the master 
to allow zone transfers from it. Configure Notify if desired.

Make sure it works, i.e. a zone transfer (AXFR / IXFR) occurs and the 
correct serial number is represented in the SOA.

Pause for another scream test.

--

Fred Morris