Very good point @bonnietwin
I posted a DoH IP Blocklist "‘DoH Protection by jpgpi250’ that could be used to block DoH servers.
Unfortunately when using it with the IPFIRE blocklist. it will block DNS DoT servers as well, not just DoH. I wonder if Proxy could block DoH even if the traffic is httpS.
Here is an example:
I think blocking DoH is only practical with DNS blocker because blocking IP 1.1.1.1 will block all DNS traffic. DoT, DoH, etc…
Blocking doh.cloudlare.com will only block DoH,
but DoT will still work.