I've been using Quad9 DNS for its security features, but this morning we had some issues with users not being able to log into ADP. I noticed that when I checked, Quad9 was pointing to a different IP than Google DNS. Once I switched to Google DNS, everything started working again. Has anyone else experienced similar issues with Quad9?
2 Answers
I've noticed that Quad9 tends to have issues with geolocation-based services. Sometimes they resolve things differently, which can mess with login systems. There are occasions when big services give out varied IPs to optimize load, so it's not too surprising. You might want to check out their ECS servers if you're having consistent problems. They generally perform better since they don't rely solely on a geofeed like some others do.
I haven't had any problems with Quad9 myself. Just to clarify, are you also using their secondary server? That might help with some consistency.
What DNS are you using then for better results?