> On 9 Mar 2015, at 14:28, Stephane Bortzmeyer <bortzme...@nic.fr> wrote: > > On Fri, Mar 06, 2015 at 08:59:20PM +0000, > Evan Hunt <e...@isc.org> wrote > a message of 28 lines which said: > >> (As an aside: I've often wondered why the DNS doesn't have *more* >> meta-query types, less extensive than ANY, such as a single type >> covering A and AAAA. > > Probably for the same reason that makes QTYPE=ANY queries very > difficult to understand for the beginner and counter-intuitive: > because it is hard to specify the semantics. Imagine there is an ADDR > meta-query covering A and AAAA. You send QTYPE=ADDR and you get only A > record(s). Can you be *sure* (and can you validate with DNSSEC) that > there was no AAAA? Think of the various cases, RD=0, RD=1, caches, > forwarders, etc.
I wrote this a few years ago: http://tools.ietf.org/html/draft-bellis-dnsext-multi-qtypes-01 The primary stumbling block was the possibility (given DNSSEC) for multiple different RCODEs for the different QTYPEs being requested. I couldn't think of any failure modes in the non-DNSSEC case, but with signed data it's theoretically possible to have valid signatures for the owner name on one QTYPE and invalid signatures on another. Ray _______________________________________________ DNSOP mailing list DNSOP@ietf.org https://www.ietf.org/mailman/listinfo/dnsop
