What is round robin ?
Round robin DNS is mathoed is used to load balance request between a number of servers.
It works from a list of IP addresses on rotation basis.
First request will be forwarded to the first IP Second reqest will be forewarded to the second IP and so on.
Every time IP is handed out it moved to the end of the list.
How to setup round robin on AD DNS ?
Windows supports round robin when IP is assigned to multiple DNS names - e.g ftp.domain.com or smtp.domain.com
First check RR is enabled at DNS level - Right Click DNS Server –> Properties –> Advanced –> Make sure RR is ticked
Add Multiple A Records
Enable Advanced option from view
Open first A record and change the TTL value - This is amount of time it will response to any client before switching to another IP
For round robin we need to set TTL to 0. Meaning first DNS lookup first IP will respond, Second DNS lookup second IP will respond