EDNS request problem on TTL=0 data

[Paul Wouters]

On Mon, 27 Jun 2011, Florian Weimer wrote:

>> 1 Is this problem happening because EDNS failure is not remembered for
>> forwarders?
>
> There is no realiable way to detect EDNS support in forwarders, so there
> isn't anything to remember, really.  Sadly, the situation with
> authoritative servers is not much better.

That is not entirely true, because bind does log a message that it is
disabling EDNS, and then gets the query out. So it could remember
that state for a little while? But currently, it appaers to not do
that, so a forwarder with broken EDNS creates havoc on a busy server
in combination with serving TTL=0 records.

Paul