On Wednesday 29 October 2003 20:05, Pekka Savola wrote: > On Wed, 29 Oct 2003, Juan Rodriguez Hervella wrote: > > On the other hand, I think that applications which > > query the DNS shouldn't be real-time applications, so I see this > > feature is not very useful. > > How do you see people browsing the web get to the websites then, if not > using DNS? That's enough realtime in my book -- the user waits while the > request(s) is being processed. > > I really don't understand what you're trying to say..
Hello Pekka! I will try to explain it better.... I just say that this option is not *very* useful, having into account the problems that it has with link-local addresses and so on... if you fix these problems, it's a matter of choice, if you want to use it, just do it. > > If I understood Stig well, he said that people was > > turning off IPv6 because of delaying issues. Doing that is not an option > > if you want to allow your app. to run over "IPv6 AND IPv4". If you can > > not cope with such delays, maybe you shouldn't be using the DNS at all. > > Then what? Distributed hosts file? ;-) ? ^--^ ...(after a while)... pouting (grrrr). Then what ? it's not my problem, I haven't switched to IPv4 because the IPv6 resolver took a couple of extra roundtrip times. I'm happy with a lot of IPv6 applications that don't use this feature at all. > > The problem here is that most of the times this feature will fail back > > to the worst case, which is the normal getaddrinfo behaviour, because > > it's not as easy as checking for global IPv6 configured address, as > > Itojun has already said. We might come up with a lot of scenarios where > > this option might fail to improve the response time (e.g: only link-local > > addresses, global addresses but no default route, proper link local IPv6 > > configuration but some black-hole on outer routers.....). > > I fail to see the point here: > > - if only link local addresses: fixed AI_ADDRCONFIG would fix > > - if global but no default route: > a) without the on-link assumption: automatic immediate no route > message and fallback to the next address > b) with (current) on-link assumption: problematic (which is why the > assumption must be killed :-) Uhm I thought that IPv6 was a piece of cake, but it might be problematic sometimes....Ops, I've got the solution, just kill IPv6 ! ;-) > > - if global, default route, but blackhole somewhere: > silently discarding packets is evil practice anyway and nothing can > be done about that, whether in case of v4 or v6. > > - if global, default route, everything works, but some DNS server munges > the AAAA queries: can't help with that, but because v6 would be > used, that has to be fixed by fixing the servers anyway. > > .. so my perception is that this would fix all the problems related to > partial IPv6 deployment I could think of w/ the elimination of the on-link > assumption pretty well. I see another way of fixing: If this option is problematic, don't use it. This has been proved to work, as a lot of applications don't use it already. You will have to give me other arguments to kill the on-link assuption. -- JFRH -------------------------------------------------------------------- IETF IPv6 working group mailing list [EMAIL PROTECTED] Administrative Requests: https://www1.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
