Subject: Question on Default Address Selection

From: "Rick LOWERY" <[email-masked]>
Date: Fri, 17 Dec 2004 18:41:34 -0500

Hello,

I ran into a scenario where I was using 6to4 on a XP machine and it preferred the IPv4 address (A) over IPv6 AAAA record for communication with sites that had both AAAA and A. I thought IPv6 was always supposed to be preferred over IPv4 when you have a valid global address.

When I connect with a tunnel broker (freenet6) it prefers the AAAA over the A. I’m hoping someone can help me further understand this. I did do some research by reading RFC 3484, but I don’t understand how to interrupt the below Prefix precedence list

Would someone please help me untangle how to interpret the below prefixes? I read in RFC 3484 that ::FFFF:0:0/96 means native IPv4, but I don’t know how they derived that from ::FFFF:0:0/96

Thanks,

Rick

Precedence  Label  Prefix
----------  -----  --------------------------------
5  p;    5  3ffe:831f::/32
10      4  ::ffff:0:0/96
20      3  ::/96
30      2  2002::/16
40      1  ::/0
50      0  ::1/128

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From: "Tony Hain" <[email-masked]>
Date: Fri, 17 Dec 2004 16:27:32 -0800

The best place to ask for product specific help is from the vendor. In this
case there is a news group set up specifically to deal with questions like
this: microsoft.public.platformsdk.networking.ipv6  (found off of
ms.com/ipv6  support).

As far as interpreting ::FFFF:0:0 /96 as an IPv4 address, see RFC 3513
section 2.5.5 . The ::FFFF prefix identifies IPv4-only endpoints to IPv6
aware environments.

Tony 

  _____  

From: [email-masked] [mailto:[email-masked]] On Behalf Of Rick
LOWERY
Sent: Friday, December 17, 2004 3:42 PM
To: [email-masked]
Subject: Question on Default Address Selection

Hello,

I ran into a scenario where I was using 6to4 on a XP machine and it
preferred the IPv4 address (A) over IPv6 AAAA record for communication with
sites that had both AAAA and A. I thought IPv6 was always supposed to be
preferred over IPv4 when you have a valid global address.

When I connect with a tunnel broker (freenet6) it prefers the AAAA over the
A. Im hoping someone can help me further understand this. I did do some
research by reading RFC 3484, but I dont understand how to interrupt the
below Prefix precedence list

Would someone please help me untangle how to interpret the below prefixes? I
read in RFC 3484 that ::FFFF:0:0/96 means native IPv4, but I dont know how
they derived that from ::FFFF:0:0/96

Thanks,

Rick

Precedence  Label  Prefix
----------  -----  --------------------------------
         5 &nbspp;    5  3ffe:831f::/32
        10      4  ::ffff:0:0/96
        20      3  ::/96
        30      2  2002::/16
        40      1  ::/0
        50      0  ::1/128