GTM/DNS: DNS records redundancy

Hi,

 

I didn't have the opportunity to attend the GTM/DNS training yet. I also didn't found any data about what I want to setup. Maybe it's a vocabulary problem from my side. So please forgive my question if it seems dumb.

 

As an internal training, I was tasked to find a way to achieve full DNS redundancy between 2 ISP lines. We currently use an external DNS provider we linked to only one ISP line. If this line goes down, DNS records aren't updated.

 

I tried the DNSMadeEasy demo and their solution is to handle all the DNS resolutions as an external service while monitoring IPs contained in a record. So if a A record contains two IPs and that one IP goes down, they send only the available IP as DNS response.

 

We would like to achieve the same behavior with F5. I created a DNS Listener and a test zones with ZoneRunner, but I didn't found how to create a monitor for all records and how to modify records when an IP is no more available.

 

Please note that there are not only VirtualSystems that must be protected by this setup. Also note than the ISP lines redundancy is already handled by a firewall. So we just need DNS records redundancy.

 

I'm sure I missed something or maybe the F5 GTM/DNS mechanism is different?

 

Thanks.