one might actually extrapolate here (and maybe look back a couple decades) ... there used to be many different transports around - and about the timethe DNS "gel'ed", most had become vestigal. We are now in the evoultionary "fork in the road" when we have an emergent, new transport that demands attention. I suspect that as things evolve, giving the DNS the ability to be transport agile is a good thing. So I don't want to be too short-sighted here and bless one or two hacks that might ease todays transitional requirements.
We should have some clear long-range thought on transport agility --bill On Thu, Apr 01, 2010 at 10:49:54AM +0100, Jim Reid wrote: > On 1 Apr 2010, at 05:25, Jason Fesler wrote: > > >Our concern is more than just "os issues". Many apps today already > >ask for A/AAAA. The bigger issue to me is related to when the host > >tries connecting to the IPv6 address, using a route that exists but > >is either broken or suffers serious performance problems. Users see > >that as "Site Down". The percentage is high [see #1]; our business > >people would never let us deploy IPv6 unless we can mitigate it by > >things like selectively enabling IPv6 towards specific operators and > >end users that appear to have IPv6 "for real". > > This is a valid concern. It does not and should not need to be > addressed (excuse the pun) by making authoritatiev servers do stupid/ > wrong/bad things. Others have already pointed out -- and it looks like > they will have to continue -- that it is just wrong to make a name > server return different data based on the network protocol used to > make the query. For starters, the thing making the query to an > authoritative server usually isn't the edge device. There's almost > always a resolving server and/or crippled middleware boxes in the > query path. And even if the edge device is IPv4 only, that doesn't > mean it has no interest in IPv6 addresses. [It's not just SMTP > delivery software that looks up MX records for instance.] Then there's > the impact on caches. If your scheme goes ahead, IPv6-capable hosts > will sometimes be told there's no IPv6 for some name because the > resolver cached that from an earlier query over IPv4 which resulted in > the authoritative server jumping to the wrong conclusion and then > telling lies. > > Why don't yahoo approach the problem the same way google has done for > IPv6 to www.google.com? They only hand out AAAA records for this name > to ISPs who can demonstrate they have solid IPv6 connectivity. This is > ugly and distasteful. But it doesn't involve egregious damage to the > DNS or resolver/cache behaviour. > > _______________________________________________ > DNSOP mailing list > DNSOP@ietf.org > https://www.ietf.org/mailman/listinfo/dnsop _______________________________________________ DNSOP mailing list DNSOP@ietf.org https://www.ietf.org/mailman/listinfo/dnsop
