DNS Conditional Forwarding, to Multiple Servers?

[Dean E. Weimer]

I am back checking in again on OPNSense, I have one feature that I have never been able to get to work correctly that has kept me from making the transition. And that one thing is DNS conditional forwarding to multiple servers. I support multiple remote tunnels with various internal DNS suffixes. Most of these DNS suffix's are managed by multiple redundant servers for example Active Directory Domain Controllers, and a few Samba servers running samba domains. I have been unable to get Unbound or DNSMasq to handle a secondary server. So if remote end reboots domain controller the lookup's start failing even though I have a secondary path available and even after primary DNS name server is back up appear to cache negative result lookup for a while until a restart of service.
The only successful solution I have found that handles this correctly is using Forward Only DNS zones (Conditional Forwarders) in Bind DNS. Though the OPNSense Bind DNS plugin has made a lot of improvements since I last checked in, it still lacks the option to create forward only zones.
Am I missing someway to do this with DNSmasq or Unbound?
In the case of the Samba DNS there is no support for slave zones so a forward zone is the only possibility, and I don't always get permissions granted to slave some zones even if I wanted to use extra overhead to run a slave zone instead of a forward only zone.

[itngo]

+1... we have same issue, but also have to live with this.
Only one DNS-Server for Conditional Forwarding....