Yes that is right, it is little difficult to find out. I have added 8.8.8.8 as DNS and google's ip address to decide whether the ISP is online or not and it is working really well. MichaelSch wrote...

Hi sylvanas, Thank you for the solution, it seems to be finally working for my TL-R470T+ load balancer. I have added the DNS lookup as 8.8.8.8 for my Wan1 keeping the ping as 0.0.0.0 and similarly...