Forum Discussion
AltocumulusLTM as balancer of pool of DNS servers
If DNS was provisioned on the box then eDNS0 would be an option. But in order to use eDNS0 you have to have a DNS profile that requires GTM provisioned: https://clouddocs.f5.com/api/irules/DNS__edns0.html.
EmployeeThere is really only one way to do this from a network perspective. If you put an interface/IP on the F5 in the 2.2.2.0/24 network. Then you would have to make the default gateway of the DNS servers be the IP address created in 2.2.2.0/24. For further HA you would need 3 IP addresses in 2.2.2.0/24, one for each F5 LTM and then a floating address. The default gateway would be the floating address. This will force all the traffic going to the DNS boxes to come back through the LTM to keep the TCP Handshakes functional.
To further complicate I have done scenarios where the DNS box has multiple routes on it. The default route goes to the BIG-IP LTM but then other routes for internal clients to a different router. But to accomplish exactly what you have asked I would use above method and make the LTM the default gateway of the DNS boxes.
