> If your "security controls" depend upon other people volunteering to use some protocol then those weren't "security controls" they were more like "guidelines"

> If your "security controls" depend upon other people volunteering to use some protocol then those weren't "security controls" they were more like "guidelines". It isn't really a matter of security controls. Anything has always been able to create an encrypted tunnel on TCP/443 and send whatever over it. The issue is administrative cost for cooperative applications. You have a local DNS that e.g. blocks known malicious domains and has the local names for other devices on your LAN. The user of each device doesn't want to prevent this, the application developer doesn't want to prevent it, but making that happen when applications default to using a third party DNS goes from setting the DNS via DHCP to changing a separate setting in every application on every device. The suggested solution to this is to have the local DNS resolve a canary domain in a particular way which Firefox takes as a request not to use DoH by default. That basically works, but I still don't know what they intend to do when adversarial upstream DNS servers start resolving the canary domain that way. It would also work a lot better if there was a standard canary domain instead of every application making up their own.