I had a client tell me today that they can't receive emails randomly from their clients. I did some searching and found that the MX records for their domain on my NS1 machine are correctly pointed at google servers and that my slave or ns2 server does not have that mx record information and is still pointing at the a record auto generated during virtualmin setup. When the transfer takes place from the primary to the slave I get the following message in the log on the slave:
Dec 28 14:47:22 venus named: transfer of 'pleasantsmiledentalcare.com/IN' from 220.127.116.11#53: connected using 18.104.22.168#57269
Dec 28 14:47:22 venus named: transfer of 'pleasantsmiledentalcare.com/IN' from 22.214.171.124#53: Transfer completed: 0 messages, 1 records, 0 bytes, 0.001 secs (0 bytes/sec)
Attached are the mx records from primary and slave so you can see the difference.
I am baffled and hope that it is a simple fix.