Disabling this setting in the pfSense web interface (System -> Advanced -> Networking, check to disable Hardware Checksum Offloading), then a reboot, and afterwards DNS from the pfSense host was working fine.
Disabling this setting in the pfSense web interface (System -> Advanced -> Networking, check to disable Hardware Checksum Offloading), then a reboot, and afterwards DNS from the pfSense host was working fine.