Bind 8.2.3, query-restart on expired NS and A record

Kevin Darcy kcd at
Thu Oct 11 22:46:07 UTC 2001

Patrick R. McManus wrote:

> [Mark_Andrews at Thu, Oct 11, 2001 at 09:17:56AM +1000]
> >
> >       The problem is you have very small TTL on the NS record and
> >       as BIND 4 and BIND 8 don't have query restart the record
> >       is timing out before the second query comes in.
> >
> >       5 minutes would be stable.
> >
> if the TTL of the NS and its corresponding A is 1 minute it will
> happen on the first query that occurs 1+ minute after they were
> written to the cache.
> if the TTL is 5 minutes it will happen on the first query that
> occurs 5+ minutes after they were written to the cache..
> same with 1 hour ttls.
> I've monitored all those cases.
> it will happen anytime the NS and A record that it refers to are
> simultaneously stale. it doesn't matter how many times they've been used.
> It happens because on the update of the NS, the additional record
> doesn't get written to cache (or used to respond to the current
> request) because the stale A isn't known to be stale and bind doesn't
> update ttls.
> I really just want to document it for the archives at this point: I
> didn't think query restarts could be triggered on zones using all "in
> baliwick" delegations and including appropos additional records.

Oh no, it's the return of the "bailiwick" bogeyman!

- Kevin

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