DNS and iRule

Hello,

 

 

With a BigIP LTM, running 9.4, I have the following setup.

 

A lsitener is defined to handle dns request.

 

I have two ISP : ISP-A and ISP-B.

 

I have defined one wide IP, let's say "www.mysite.com"

 

This wide IP have two VS members.

 

The first one is VS_ISP_A whose the ip address is routed only by ISP-A.

 

The second one is VS_ISP_B whose the ip address is routed only by ISP-B.

 

Each Virtual Server have the same pool member, the real internal Server (only one).

 

 

If the two ISP links are working fine, there is no problem, the BigIP answers do DNS request with both Virtual Server Ip Address.

 

 

The problem is the following : if ISP-B becomes unavailable, the BiGIP is still answering with both Virtual Server IP Address whereas the VS_ISP_B can't be reached from Internet.

 

The reason of this behavior is that both VirtualServer are still UP, from BigIP point of view.

 

 

Do I need to use iRule (for instance through event "DNS_REQUEST") or is there a way to mark the VS_ISP_B "red" when the ISP-B is unavailable ?

 

 

(I have tried to use other "Health Monitors" on the members of the wide IP but it seems not to be a good idea).

 

 

Thanks by advance.

 

GlP.