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Re: "DNS-4to6 automatic mapping" - No more DNS-ALGs & 6then4 DNS queries
I'm sorry, turning off IPv6 routing does not imply the userland should not
and cannot query for v6 addresses. That's just bogus. The operating system
can inform the application that the v6 address has no route, and the
application can try the next address, just as if it were a v4 host with
multiple v4 addresses, and the first one is not reachable, only faster,
because no default route means the application will get notified much
sooner.
Thanks,
--
Todd Fries .. todd@fries.net
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Penned by Nathan Ward on 20071129 16:45.40, we have:
> On 26/11/2007, at 10:42 PM, Iljitsch van Beijnum wrote:
>>
>> The question is: do we really have a problem?
>>
>> Yes, people recommend turning off IPv6 on forums here and there, but this
>> used to be because there were some DNS servers out there that would reply
>> with an error when queried for AAAA records. That problem has been solved
>> 99.9%, unless I'm mistaken. Also, apparently turning off IPv6 helps agains
>> all kinds of problems that are provably IPv6-unrelated.
>>
>> I think any effort would be better spent by making sure OSes don't send
>> AAAA queries when there is no IPv6 connectivity.
>
>
> I agree with this.
> The major case that I see is Windows firing up 6to4 when it has a
> non-RFC1918 address, when it's connectivity is filtered or NATed.
>
> What other common cases are there, that are not due to misconfiguration
> (i.e. IPv6 `default' route configured on an interface/link without IPv6
> transit doesn't count).
>
> --
> Nathan Ward
>
>
>
>