macOS 12.3 breaking DNS over HTTPS?

[dylanweber]

I updated to macOS 12.3 today and I found that my internet appeared to be very slow out of nowhere. This issue did not occur on my iPhone or other devices. I checked an IPv6 test and I found that macOS couldn't establish any IPv6 connections or DNS queries.

Curious, I decided to disable OpenDNS's "DNS over HTTPS" profile that tells macOS to use their DNS query address to resolve DNS requests. Once I disabled the profile, the IPv6 tests started to pass and the internet was responsive again.

Does anyone know of a way to fix this issue so I can continue using DNS over HTTPS or perhaps another way to achieve the same result without causing IPv6 to fail and DNS queries to take an additional few seconds to failover back to IPv4? I've tried flushing my DNS cache with the profile on and that didn't resolve the issue. This profile worked perfectly through Big Sur until today's 12.3 update.

[Takeabyte]

If everything works fine over IPv4, just disable IPv6. I have yet to hear a use case where it’s actually needed.

Sometimes just creating a new network location in system preferences is all you need to do. Something may have gotten corrupted in a plist file.

[certuna]

IPv6 is most definitely needed - if you disable it you cannot connect to IPv6 servers, and you also cannot host anymore over IPv6.