Feature request: Enable DoH for custom DNS server

[c-b-x]

Issue type

Other

Device

I use the build for sweet but this is not device specific.

crDroid version

crDroid 11

Exact version / Build date

This applies to the latest crDroid 11 and 12 at this time.

Bug description

Google limits advanced DNS features to Google.dns and Cloudflare. With advanced DNS features I mean DNS-over-HTTPS (DoH) which uses Port 443 and QUIC even though that is supported by many if not most alternative DNS providers like Quad9, NextDNS, Adguard, DeCloudUS just to mention a few but also self-hosted solutions. If you choose anything but Google or Cloudflare in the PrivateDNS setting, resolution will happen using DNS-over-TLS DoT (if available) which uses Port 853. This port is often intentionally or unintentionally blocked in (Wifi) networks. Usually it is just blocked because it is not one of the classic standard ports. This means PrivateDNS has to be turned off manually in such networks or switched to Google/Cloudflare. For browsing a workaround is to configure the DNS in the browser itsellf as supported by Chromium and Firefox based browsers. For every other software DNS won't work otherwise. There are of course ugly workarounds based on Androids VPN support.

Steps to reproduce

Go to Android settings - Network - PrivateDNS.
Configure any DNS provider other than Google or Cloudflare.

Relevant log (logcat/build log)

I don't see anything related in logcat but I can provide evidence using Netguard if required.

Screenshots or videos

No response

Solution

The private DNS settings in crDroid are already modified. However, instead of offering just a few preselected DNS providers, I would like the custom option to be extended so that I can also use a custom URL not just a hostname and also enable DoH and/or QUIC. I suspect Google has added arbitrary limitations which could be relatively easily disabled if you know where to look.

Additional context

A discussion on DoH support in Reddit just for some additional context:

https://www.reddit.com/r/nextdns/comments/zxdmt6/how_do_i_add_the_dns_over_https_server_to_the/

Acknowledgements

• I've checked device is officially supported and that no support is provided for unofficial devices (for device specific reports and not source related).
• I'm running latest version available on crdroid.net for this device and that the device is still maintainer supported (not flagged unsupported on download page)
• I have searched the existing issues and this is a new and no duplicate or related to another open issue.
• I have written a short but informative title.
• I filled out all of the requested information in this issue properly and understand that not doing so will automatically result in closing of ticket.

[eepymeowers]

To add to this, I think LibreDNS (particularly the noads one) would be a nice addition to the Private DNS settings in crDroid.

[c-b-x]

You can already.use libreDNS by using dot.libredns.gr as custom DNS provider but it will be limited to DNS over TLS just like any other provider in Android.

I don't find the predefined list too useful. If you want to know how these providers differ, what the their policies are, what they filter etc. you have to look it up manually on the web anyways. If you don't care about these details, Google DNS or Cloudflare DNS is just fine.

My request doesn't prefer to any specific provider, although I personally do use a specific service. Just to be clear, hopefully, I want the features most importantly DNS-over-HTTPS to be unlocked for all custom DNS providers. This is a standardized protocol (RFC 8484) supported by all of the already included DNS providers and more. There is no technical reason for Android (or Google) to limit this protocol to their own DNS and Cloudflare.