@digitalgimpus said in Random DNS Resolver failure with Quad9 over SSL:
I'm running 1.18.0.
Yes, it is helpful in the future for posters having issues with DNS or DHCP to post the pfSense branch they are using (CE or Plus and which version). The underlying binary components of the DNS Resolver and the DHCP server are quite different between the current 2.7.2 CE branch and the latest 24.11 Plus branches, for example. A number of unbound bugs were fixed upstream in the newer version released with pfSense Plus 24.11 as compared to the much older version bundled back with pfSense 2.7.2 CE.
Ditto for kea, the new DHCP server that came out first with 2.7.2 CE. The kea binary and its connections to the DNS Resolver are quite different from (and much more feature-rich) than the original kea still bundled with pfSense CE.
When a poster does not state their pfSense version (and thus, by extension, the version of unbound or kea) they are running, it is easy for responders to make false assumptions. For instance, "it's working fine for me" might be true if you are using the latest unbound on pfSense Plus 24.11, but something may well be broken on the older unbound that is bundled with pfSense CE 2.7.2. This is a natural consequence of the growing divergence between features and versions of packages included in pfSense 2.7.2 CE and those of pfSense Plus 24.11 (and soon, 25.03).