How-To Manually Configure DoH in Firefox?

Do you want to use (or not use) DoH all the time? Use the configuration editor to configure DoH if you want to test DoH outside of a shield study. DoH support works best in Firefox 62 or newer. Shield studies will not override your manual configuration.

1] Type about:config in the location bar

2] Search for network.trr (TRR stands for Trusted Recursive Resolver – it is the DoH Endpoint used by Firefox.)

3] Change network.trr.mode to 2 to enable DoH. This will try and use DoH but will fallback to insecure DNS under some circumstances like captive portals.  (Use mode 5 to disable DoH under all circumstances.)

4] Set network.trr.uri to your DoH server. Cloudflare’s is https://mozilla.cloudflare-dns.com/dns-query but you can use any DoH compliant endpoint.

The DNS tab on the about:networking page indicates which names were resolved using the Trusted Recursive Resolver (TRR) via DoH.