On 03/30/2017 12:58 AM, Daniel Kahn Gillmor wrote:
I'm running kresd 1.2.4. If i start it with
an empty/missing cache, and
then receive a query for an A record for "www.ietf.org", there is a
substantial delay in the response.
[...]
In particular, the delay appears to be related to resolving AAAA records
for'ns1.yyz1.afilias-nst.info, but i don't know why. i do note that the
first time it shows up it's answered with "=> using root hints", but
then subsequent times don't seem to say that. I'm not sure what this
means.
Note the multiple pauses in the server timeline, as the resolver seems
to go quiet.
can anyone reproduce this result, or help me to interpret the logs?
I'm unable to reproduce this, unfortunately, and that makes finding the
cause harder. Does it often happen to you?
There's one probably unimportant thing that puzzles me in the log - the
plan to find
www.ietf.org AAAA at 15:29:25. It happens when the clients
you show only have asked one request - for
www.ietf.org A. It appears
as if some client has asked it explicitly precisely at that time - is
that possible?
I suspect that request for AAAA comes from web browser or similar
application which attempts to resolve address
to A/AAAA in
parallel. ("I'm still waiting for A for seconds, let me try AAAA ...")
--
Petr Špaček @ CZ.NIC