In message <20160412000120.ga63...@isc.org>, Evan Hunt writes: > On Mon, Apr 11, 2016 at 09:13:42PM +0000, Adrien de Croy wrote: > > If we simply added a new QTYPE which permitted a server to respond with > > all matching A and AAAA records then that would solve a lot of problems. > > As far as I've seen, all of these suggestions share the same problem: > No matter how the multiple-QTYPE query is implemented, EDNS option or > meta-type or whatever, you can't know in advance whether an authoritative > server will support it, and you won't want to waste a whole RTT waiting to > find out, so you're going to send simultaneous A and AAAA queries *anyway*.
Now, Yes. In x years time, No. It is possible to get reasonably high levels of support quickly. It is also possible to cache whether a remote server supports functionality in the interim. > So, unless I'm missing something (certainly more than possible), I don't > see server workloads or client latency being significantly reduced by the > deployment of a mechanism like this. > > I agree it's a sensible idea to combine queries when possible, and I wish > a meta-type of the sort you describe had been included when the DNS was > designed originally. But at this point, if we want to change the way > lookups work, the early adopters need to see a real benefit. At this > point, I mostly only see costs. The costs are minimal. A bit of developement cost on the part of nameserver and stub server developers then you just wait for components to be updated. We will waste more developer time arguing over this than just doing it. The key things needed are 1) a way to determine if the server supports the extension and 2) defining the extension such that you get a response for all types both positive and negative. Mark > -- > Evan Hunt -- e...@isc.org > Internet Systems Consortium, Inc. > > _______________________________________________ > DNSOP mailing list > DNSOP@ietf.org > https://www.ietf.org/mailman/listinfo/dnsop -- Mark Andrews, ISC 1 Seymour St., Dundas Valley, NSW 2117, Australia PHONE: +61 2 9871 4742 INTERNET: ma...@isc.org _______________________________________________ DNSOP mailing list DNSOP@ietf.org https://www.ietf.org/mailman/listinfo/dnsop
