Ok this is the solution that I've found:
- I've added in my mysql master-master replication of the mail tables also the part of the database regarding the dns.
- I've create a bash script that is running on SRV2 and that basically ping the SRV1 and, after 20 ping failed, will update in the dbispconfig:
"UPDATE dns_rr SET data = 'IP_SRV2' where data = 'IP_SRV3';"
I've tested it and it's working.
During this test I've setup this DNS Zone Values:
Refresh = 60
Retry = 600
Expire = 604800
Minimum = 60
TTL = 60
Now it's time to find the right values for this configuration.
I was reading what does this values means and I found something here: http://www.interworx.com/support/doc...-zone-defaults