Bind can not resolve.

Mark Andrews Mark_Andrews at isc.org
Thu Mar 29 00:16:32 UTC 2007


> On Wed, Mar 28, 2007 at 05:37:44PM +1000, Mark Andrews wrote:
> > 
> > > bind9 seem to be unable to resolve if during resolution of an A record a
> > > CNAME is returned pointing to a parent domain without the corresponding A
> > > record.
> > > 
> > > Example: cname.bind9.expol.us
> > > 
> > > Trying CNAME first makes A resolution work, otherwise I get SERVFAIL.
> > 
> > 	It would help if the authorative servers actually followed
> > 	RFC 1034.  The server should be including the A record in
> > 	the answer as it serves the parent zone.  If should also be
> > 	returning a referral to the parent zone (not the child zone)
> > 	if it returns the implicit referral.
> 
> Could you point me to the sections of RFC 1034 which back up your two
> points ? I was only able to find recipes for recursive nameservers:
> 
> 5.3.3
>          c. if the response shows a CNAME and that is not the
>             answer itself, cache the CNAME, change the SNAME to the
>             canonical name in the CNAME RR and go to step 1.

	The corresponding authoritative behaviour is here.

4.3.2. Algorithm

   3. Start matching down, label by label, in the zone.  The
      matching process can terminate several ways:

         a. If the whole of QNAME is matched, we have found the
            node.

            If the data at the node is a CNAME, and QTYPE doesn't
            match CNAME, copy the CNAME RR into the answer section
            of the response, change QNAME to the canonical name in
            the CNAME RR, and go back to step 1.


> 
> In case of cname.bind9.expol.us bind9 for some reason does not restart
> the query and we have a problem. 
> 
> 
> 
> Pawel
> 
> 
> > -- 
> > Mark Andrews, ISC
> > 1 Seymour St., Dundas Valley, NSW 2117, Australia
> > PHONE: +61 2 9871 4742                 INTERNET: Mark_Andrews at isc.org
> > 
> 
> -- 
> 
> 
-- 
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: Mark_Andrews at isc.org



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