The DNS agent updates and monitors the mapping for the following:
The host name to IP address (A, AAAA, or PTR record)
Alias to hostname or canonical name (CNAME)
The agent performs these tasks for a DNS zone when failing over nodes across subnets (a wide-area failover). Resource records (RR) can include different types: A, AAAA, CNAME, and PTR records.
Use the DNS agent if the Resource Records need to be dynamically added and deleted from the DNS servers during failover. The agent updates the name server with the new resource record mappings while failing over and allows the clients to connect to the failed over instance of the application.
For important information about this agent, refer to Agent notes for DNS agent