[109433] in North American Network Operators' Group
Re: IPv6 routing /48s
daemon@ATHENA.MIT.EDU (Florian Weimer)
Fri Nov 21 10:56:00 2008
From: Florian Weimer <fw@deneb.enyo.de>
To: Mohacsi Janos <mohacsi@niif.hu>
Date: Fri, 21 Nov 2008 16:55:42 +0100
In-Reply-To: <alpine.BSF.2.00.0811200912550.60025@mignon.ki.iif.hu> (Mohacsi
Janos's message of "Thu, 20 Nov 2008 09:22:30 +0100 (CET)")
Cc: nanog list <nanog@nanog.org>
Errors-To: nanog-bounces@nanog.org
* Mohacsi Janos:
> On Thu, 20 Nov 2008, Nathan Ward wrote:
>
>> On 20/11/2008, at 4:06 AM, Florian Weimer wrote:
>>
>>> * Michael Sinatra:
>>>
>>>> And it just reinforces the fear that people have against putting AAAA
>>>> records in DNS for their publicly-accessible resources, especially
>>>> www.
>>>
>>> Won't current Windows clients work just fine in this case?
>>>
>>> I have no idea what a fix should look like for some of the non-Windows
>>> systems I care about, unfortunately.
Do you mean that the client tries to enable 6to4 unsuccessfully?
>> No, unfortunately broken 6to4 auto-configuration (ie, in Vista,
>> XPSP2, when on a non-RFC1918 IP address) breaks, and you get 90s
>> timeouts before falling back to IPv4/A.
>
> This must be a broken RFC 3484 implementation:
> - 6to4 should be less prerefed than IPv4 if the service has both AAAA
> and A record.
RFC 3848 generally prefers IPv6 over IPv4 and fails if the host
running its algorithm has neither IPv6 connectivity nore mean to
detect that efficiently. I think Windows does something in the second
area.
