bert hubert <bert.hub...@netherlabs.nl> wrote: > On Mon, Mar 09, 2015 at 11:08:03AM -0000, D. J. Bernstein wrote: > > My "qmail" software is very widely deployed (on roughly 1 million SMTP > > server IP addresses) and, by default, relies upon ANY queries in a way > > that is guaranteed to work by the mandatory DNS standards. > > The way I read RFC 1034 4.3.2, this is not true. In step 4 we match whatever > we find in the cache, put it in the packet, and move on to step 6. > > This means the algorithm might terminate returning only an A record or only > an AAAA record. Or a TXT record for that matter. > > This reading of 4.3.2 makes 'ANY' queries to resolvers fragile. It might not > return what you need.
Dan is aware of that, but this particular oddity isn't a problem for qmail. Later in his message he wrote: > > Of course, there's no guarantee of which RR types for a node are > > available at a cache, but a client is guaranteed to be able to detect > > CNAME records from responses to query type ANY (as qmail does), since > > a CNAME type prohibits all regular RR types. Tony. -- f.anthony.n.finch <d...@dotat.at> http://dotat.at/ Fair Isle: Southeast veering west, severe gale 9 to violent storm 11. Very rough or high, becoming very high for a time. Rain then showers. Moderate or poor, becoming good. _______________________________________________ DNSOP mailing list DNSOP@ietf.org https://www.ietf.org/mailman/listinfo/dnsop
