Add option to adjust IPv6 prefix policy

[jwgn]

By default, windows prefers IPv4 over IPv6 ULA addresses via prefix policies:

Vorgänger   Label  Präfix
----------  -----  --------------------------------
        50      0  ::1/128
        40      1  ::/0
        35      4  ::ffff:0:0/96
        30      2  2002::/16
         5      5  2001::/32
         3     13  fc00::/7
         1     11  fec0::/10
         1     12  3ffe::/16
         1      3  ::/96

As a result, local hostnames are always resolved over IPv4, even when ULAs are correctly configured in the network.

It can be fixed with this command: netsh int ipv6 set prefix ::ffff:0:0/96 2 4 which lowers the priority of the IPv4 prefix.

It may also be a good idea to favor ULAs over GUAs.

Can we have this configurable via Unattend-Generator?

[cschneegans]

If you want to prefer IPv6 over IPv4, the DisabledComponents registry value seems like the way to go.

But in any case, this should be done with a custom script, not with a dedicated setting in the generator.

[jwgn]

No, DisabledComponents does not help here at all. IPv6 is preferred over IPv4 by default, but that does not apply to SLAAC / ULA addresses. fc00::/7 always has lower priority.

Yes, I've done this with a custom script, just thought it would be nice to have a setting for this in the generator.