We support two different DNS Failover methods. Sequential and Round Robin.
Sequential Method: This method uses the server IP addresses one by one in the order they are entered. That way, you always have one IP address announced for your ‘A’ record, which is considered a primary server. Should that server go offline, the failover service will automatically change the ‘A’ record to the IP of the next online server in your failover pool. You can have as many backup servers as you would like. It will monitor them all to know which are available so it can quickly make the change during an outage.
Round robin method: This method uses all of the server IP addresses for servers that are currently online. Should it detect that one of them goes offline, it will simply delete the ‘A’ record for that one server only and continue directing traffic to the remaining servers.
You might also be interested to know that if DNS Failover is critical to the success of your business, we offer Cloud Load Balancing too. Cloud Load Balancing does DNS Failover much faster, and without the TTL issues. Contact sales or check out our website for more details!