Bug in bind? MX and no A record

Winfried Magerl winfried.magerl at mch.sbs.de
Mon Jul 19 16:49:13 UTC 2004


In article <cdaufg$9il$1 at sf1.isc.org>,  <kernel at pkts.ca> wrote:
>Hi..
>
>I've been debugging an email problem.  A domain (example.com) has an
>MX record but no A record.
>
># killall named
># named
># dig example.com mx
>  * this works
># dig example.com
>  * this says 'NXDOMAIN'
># dig example.com mx
>  * now this says 'NXDOMAIN', but it worked 2 seconds ago!?
>
>The MX record won't come back until named is restarted.  It might come
>back after the negative caching timeout, but I'm Not That Patient(tm).
>
>This is with BIND 9.2.2 and also today's BIND, 9.3.0rc2.
>
>Reproducible?  Real bug?  Design feature?  Let me know.

I've seen a similar behaviour in then past. The proprietary nameserver
authoritative for the domain acts broken.
The server answers with NXDOMAIN instead of NOERROR when asking for the
non-existing a-record. bind9 caches the answer and the next request
for the mx-record returns the cached NXDOMAIN.

regards

	winfried

-- 
Winfried Magerl - Internet Administration
Siemens Business Services, 81739 Munich, Germany
Internet-Mail: Winfried.Magerl at mch.sbs.de


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