Ubiquiti Network Application — Odd DNS Behaviour

On a Ubiquiti DreamMachine, you may notice unexpected DNS resolution.

This occurs because there are three places you can specify an upstream resolver:

1. Settings → Internet → WAN → DNS Server;
   (This is a default resolver per WAN connection.)

2. Settings → Security → DNS Shield;
   (This allows the device to resolve DNS queries with DNS-over-Https using predefined resolvers or specific resolvers.)

3. Settings → Networks → (Network) → Content Filtering.
   (If enabled, this allows per-network resolvers provided by CleanBrowsing.org which override the other DNS resolvers.)

Generally speaking, you should use only one of these mechanisms.