Configuring Secondary DNS Servers of Third-Party Providers

If you want the Primary DNS to send NOTIFY messages (notifications from the primary DNS when changes occur in the domain zone) to its known clients, you must specify the list of your Secondary DNS servers in the DNS hosting service settings under the Zone Transfer section.

For a Secondary DNS server to be able to receive NOTIFY messages from the Primary DNS, you need to add the following addresses to the ACL (Access Control List) of your server:

109.70.30.64/26
109.70.29.64/26
or
109.70.29.93
109.70.29.94
109.70.29.95

After that, the zone transfer process must be initiated from the Secondary DNS server if its databases are empty, and subsequently performed according to the schedule defined by the refresh, retry, and expire fields in the SOA record.