Block all port 53 traffic from your network outside of your DNS server/pihole itself.
Block all known DoH servers.
If you want to get REALLY fancy you can write a NAT rule that will force any outgoing request on port 53 to route to your dns/pihole.
I do all of this. It’s actually funny to see the requests that were hardcoded to go somewhere. Giant fuck you to those companies.
So am I. I’m not sure what you think wasn’t relevant. It’s a literal DoD spec. Yes that spec is outdated, but it’s still in Dban.
You coming out of nowhere talking about how the DoD spec itself is “dead” doesn’t change the fact that it’s available and probably still used by many people out there. I’m willing to be that several companies have the old DoD spec embedded in their own SOPs. And I was always talking in the context of the contract work I did long ago which WAS to the old DoD spec regardless.