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Re: Operational experience with 3 degrees

>>>>> On Thu, 20 Mar 2003 23:19:10 +0100 (CET), 
>>>>> Erik Nordmark <Erik.Nordmark@sun.com> said:

>> If IPv6 enabled on machine, IE will call "getaddrinfo" which in conformance
>> with the IETF recommendation will look for AAAA record for the web site, and
>> then look for an A record if there is no AAAA available. The problem is
>> that, upon receiving a query for a AAAA record, some DNS servers returned a
>> "no such domain" error, upon which getaddrinfo gave up. The issue affects
>> about 20 of the top 500 web sites. We are glad that we found it during a
>> limited size beta rather than during a wide scale deployment. We are working
>> with the vendors of the affected DNS products and are confident that the bug
>> will soon be fixed.

> Is this caused by load balancing boxes?
> This is an issue for IPv6 deployment in general and not specific
> to Teredo. If it would be useful
> to have a document to point the vendors to, perhaps we can arm-twist somebody
> to write a short document (could be done in dnsop or by a
> willing individual I think?)

I agree.  As far as I know, there are several "broken" DNS servers (or
load balancers) wrt AAAA queries:

- some of them return NXDOMAIN against AAAA (as reported in this thread).
- some ignore AAAA queries (causing a delay to fallback).
  you can see this when you try to resolve AAAA for "ftp.mozilla.org"
  at 64.12.182.70 (gdns-02-ftp-dom.ns.aol.com)
- some return broken answers for AAAA queries.  Some resolvers
  handle such cases as "server fail," and will not use the servers).
  you can see this by asking an AAAA RR for "www.gslb.mainichi.co.jp"
  at 210.173.172.2.
- some constantly indicates a (loop) delegation for any queries except
  A.  Resolvers interpret this as a lame delegation.  You can see this
  by asking AAAA for "www.united.com" at 64.95.89.4.

I guess there may be a comprehensive document already, but I myself
don't know one.

					JINMEI, Tatuya
					Communication Platform Lab.
					Corporate R&D Center, Toshiba Corp.
					jinmei@isl.rdc.toshiba.co.jp