my active device is (device 1) and my website working fine. when auto faliover happend the active device (device1) become standby , the traffic goes to the active device ( device 2) but my website does not work . it is display blank page only. when i enforce device 2 to becaome standby and device 1 become the active, my website works well.
so what i have to check in this case? note that both device are in sync.
Three things I would check.
1. Do a tcpdump on the BIG-IP device 2. Check what is going on.
2. Did you configure MAC masquerade? If MAC masquerade doesn't mean anything to you - start from here: K15858: How BIG-IP utilizes gratuitous ARP
3. Are ASM policies synced in your device group? Read this: K12200102: Enabling Application Security Synchronization on a device group
Really silly questions.
But what do you health monitors say on each part of the cluster?
What happens if you disable the waf profile on device 2 (now active).
Are you sure it's the waf profile?
Both BIG-IP'S do health monitors in their own right.
Other than that ASM sync would be my next thing to check, also ensuring your failover sync is setup correctly. (Check the advanced settings just to make sure)