[dns-operations] DNS cookies in a mixed resolver anycast environment

[Tobias S. Josefowitz]

On Mon, Jun 3, 2019 at 11:45 AM Ondřej Surý <ondrej at sury.org> wrote:
>
> https://tools.ietf.org/html/rfc6891#section-7

I read it thrice more now - and I do not get it. Is it because
standards compliant responders pre-EDNS never had any chance to
respond anything but a FORMERR once something as odd as an OPT showed
up in the additional section of the query?