Win7 & ULA prefix selection policy

[Brian E Carpenter]

Tassos,

You can use 'netsh interface ipv6 set prefixpolicy' to update
the policy to RFC 6724. I agree it would be nice if MS issued
a patch for this, but it's a simple sysadmin script.

Regards
   Brian

On 21/11/2013 00:48, Tassos Chatzithomaoglou wrote:
> After experimenting a little with ULAs, i noticed that Win7 uses ULA as source in order to connect to a global IPv6 address, while at the same time destroying the quick switchover effect of HE. Linux on the other hand doesn't seem to suffer from the same issue.
> 
> I did a quick search and i found out that this is expected behavior, so a solution from MS shouldn't be expected any time soon (although there is a workaround by changing the prefix selection policy).
> 
> C:\Users\Tassos>netsh interface ipv6 show prefixpolicies
> Querying active state...
> 
> Precedence  Label  Prefix
> ----------  -----  --------------------------------
>         50      0  ::1/128
>         40      1  ::/0
>         30      2  2002::/16
>         20      3  ::/96
>         10      4  ::ffff:0:0/96
>          5      5  2001::/32
> 
> 
> Latest rfc 6724 defines a specific policy for ULAs, while the older one rfc 3484 didn't:
> 
>       Prefix        Precedence Label
>       ::1/128               50     0
>       ::/0                  40     1
>       ::ffff:0:0/96         35     4
>       2002::/16             30     2
>       2001::/32              5     5
>       fc00::/7               3    13
>       ::/96                  1     3
>       fec0::/10              1    11
>       3ffe::/16              1    12
> 
> Does anyone know if MS has any plans to implement the newer RFC? It's almost a year since the RFC came out.
> Dave as an author might be a hint, but i have seen many similar cases without the expected result.
> 
>