> Thanks, Piete. That may be what is happening, but Lee reports that a
> second query gets the data, whereas your nameserver gives the same
> result each time. Maybe in Lee's case it is first asking some remote,
> non-recursive NS and then next time trying a different one for the zone
> which happens to be OK?
That is not the way resolvers tend to work.
They are pretty dumb (they do not have state as a NS does), and work through
(WLOG) resolv.conf trying each one in turn until it gets a reply.
It could be simpler than that ...
I have not read the code of his NS, but it would be perfectly feasible for a
NS with recursion enabled to try to be helpful and recurse, but on not
receiving any reply within a certain timeout, reply with the data which it
actually holds (which would be of use if its client were a NS).
Some time later, the reply does return, so on the second lookup, it would be
returned normally.
The old problem as per SMTP -- different behaviour is optimal if the client is
itself a server (NS or MTA) than if it is an end user (resolver or MUA).
:-(
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