DNS inbound link load balancing with failover

[rohitchoudhary1978]

Hi Friends,

I want to use my fortigate 600c with firmwre version is FG600C-5.02-FW-build727-160629 and want to configure it as link load balancer that when my clients connect to my fortigate, the box connects to the application server in round robin and if 1 ISP gets down box automatically transfer loads to another ISP. I have 2 ISP presently and have my domain at godaddy and will create A records of my 2 ISP ip configured at box e.g., ISP 1 = 1.1.1.2 = A record = lb1.xyz.com and        ISP 2 = 2.2.2.2 = A record = lb2.xyz.com test.xyz.com = ns record = lb1.xyz.com test.xyz.com = ns record = lb2.xyz.com when 1 gets down it automatically routes to another isp, i mean when client nslookup test.xyz.com he'll get 2 ip 1.1.1.2 and 2.2.2.2 and in case ISP 1 gets down he will get only one result of ISP2 i.e., 2.2.2.2. I did this after enabling DNS Server but unable to load balance and created dns failover. If its done then accordingly VIP configured on FGT to route to that servers private IP.

My purpose is to serve my users if they gets only one isp responding then it connects through that and not unnecessarily gets a failed response from the failed ISP.

Please go through the attached image and documentation what i want to achieve.

Thanks Rohit Kumar