BIND 9.11 no longer respects edns-udp-size?

[Chris Buxton]

On Mar 11, 2019, at 7:12 AM, Tony Finch <dot at dotat.at> wrote:
> 
> Stéphane Bortzmeyer <bortzmeyer at nic.fr> wrote:
>> 
>> Does minimal-responses make sense for an authoritative name server?
>> (Note there was no glue involved.)
> 
> I think it helps reduce fragmentation if the max-udp-size is larger than
> the MSS, but apart from that it probably doesn't make much difference.
> 
> As far as I can tell, clients and resolvers generally re-query for
> additional records when they are needed, and they already have the
> delegation records which should be the same as the authority records, so
> it seems pointless to me to add records to authoritative responses when
> they aren't used.

Enabling minimal-responses on an authoritative server will break any other server with a stub zone declaration with this authoritative server listed as master. The implementation of stub zones assumes that an SOA query will retrieve all of the required information (SOA, NS, and supporting A/AAAA records) to successfully insert the zone apex into the cache.

Chris Buxton