on TTL expiry BIND sends 'ANY' query, gets back 'NOANSWER'

Tony Finch dot at dotat.at
Mon Apr 13 12:48:16 UTC 2015

Phil Mayers <p.mayers at imperial.ac.uk> wrote:
> TBH I wonder if bind mightn't be better caching ANY as a separate
> pseudo-type, if I'm understanding the problem correctly.

Actually I think you are asking for BIND not to treat ANY specially :-)

If BIND gets a positive answer to an ANY query, it caches each RRset from
the response individually. There is no separate positive ANY cache entry.
This means that if you query for a type which was not present in the ANY
response, BIND will pursue that query upstream. This is necessary because
ANY responses can be incomplete. When BIND gets a NODATA response to an
ANY query it creates a special cache entry which matches any query type,
so subsequent queries for the same name will get a cached negative
response regardless of the type.

You are asking for these negative cache entries to match only ANY queries,
not queries for other types, so they behave like normal NODATA cache

f.anthony.n.finch  <dot at dotat.at>  http://dotat.at/
Fisher, German Bight: Northwest 6 to gale 8, decreasing 4, backing southwest 5
or 6 later. Moderate or rough. Showers. Good.

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