Custom DNS Forwarding Options
We've recently discovered that doing resolving instead of forwarding in our pfSense boxes sporadically takes down some modems. I guess it's related to sudden bursts of DNS traffic over PUMA based chipsets in the modems. Switching to forwarding seems to resolve the issue. In these cases I'd like to know what options are out there for DNS forwarders. I know there are free servers like OpenDNS and Quad9 but I'd like to choose one that is customizable. For example, I've had issues with OpenDNS blocking things like Google Cache, VPN, and Virtualization sites.
I know a lot of these places charge by the user but if the firewall is the one connecting to them, is it considered a single user? If there is someone who has set up custom DNS servers in the forwarders I'd appreciate the feedback to how it all works. Thanks.