My own code to decode DNS packets [1] fell afoul of section 3.1.3 of the draft document. I fixed the issue, but the reason I originally rejected DNS packets with unknown flags was on the assumption of potential garbage being used as a possible exploit.
I don’t read that as DNS stoping to work, but more reasons why DNS is flaky in different scenarios.
Some of the issues there are things related to mitigation’s against reflection attacks etc. I haven’t read the entire doc, but does it go into concerns around DDOS and other such things, and how DNS servers to mitigate those attacks?
Edit: right in the intro. So a server needs to “understand” when it is under “attack” and only then put in mitigations against the attack. In the worst case, the server doesn’t do this, fixes the issues in this RFC to always respond and then amplify the attack.
[1] https://github.com/spc476/SPCDNS