Howdy, folks.
tldr; I'm looking for detailed docs on the default GrapheneOS DNS config.
The GrapheneOS nodes in my household are proliferating. I have a rather extensive internal LAN with some custom DNS configurations for ad blocking etc. I notice that the GOS phones and tablets seem to be bypassing the internal DNS as they are not getting the same level of ad blocking and they are not able to resolve internal hosts/services. From my time with LineageOS I know that Android is a little odd about how it handles DNS by default. From digging around in GOS it looks like it defaults to enabling the "Private DNS" setting. That setting is not well documented in the Google Android docs but using an educated guess I would say its perhaps DNS-over-TLS/HTTPS to an external provider. I don't see a default specified but probably Cloudflare?
When I disable this setting and reconnect to the WiFi (thus getting new DHCP settings) I'm still not able to resolve the internal hosts. In fact, I'm not able to resolve anything and turning it back on doesn't resolve. I have to reboot the device.
I'm going to run off and set up a SPAN port on the switch but perhaps in the meantime someone can provide a pointer to detailed docs on the default DNS config in GrapheneOS?
Related...I have quite an extensive background with systems-level stuff in various free NIXes but I've never found a great reference for learning about how Android works at the OS level. Perhaps someone has a pointer to that sort of thing also?
thx