GTM responds "no such name" and avoid switch to second/third dns

Hi,

 

- We have 3 x GTM machines configured with the same WIP (www.db1.com and www.db2.com). No synchronization is set.

 

- When a client triggers for instance www.db1.com, it get 5 oracle servers ip adresses. The GTMs are consfigured as primary/secondary/third DNS servers.

 

- 2 days ago, one of our GTMs started to answer clients with "no such name" :-( while the WIP is configured.

 

- The point is that, considering that "no such name" is an answer (no timeout), Clients DNSs did not switch to th second/third GTMs.

 

 

Have few questions and would be happy if some one can advise:

 

 

1/ What could the reason for this unexpected message "no such name" while the WIP is present on GTM configuration and Bind

 

 

2/ Is there any work around to avoid such chaotic issues and redirect the DNS queries to the second/third DNS or even to a fall back answer (pool or ip).

 

Thanks.