Re: [v6ops] ULA precedence [Thoughts about wider operational input]

[Erik Auerswald <[e-mail]>]

Hi,

On Mon, Apr 25, 2022 at 09:16:14AM +0900, Lorenzo Colitti wrote:
> On Mon, Apr 25, 2022 at 2:28 AM Erik Auerswald <[e-mail]>
> wrote:
> 
> >  "Since ULAs are defined to have a /48 site prefix, an implementation
> >   might choose to add such a row automatically on a machine with
> >   a ULA."
> >
> > The result is that only the local ULA prefix, i.e., exactly the
> > local IPv6 addresses, are preferred over IPv4 (and IPv6 GUA).
> > This should be exactly what is needed to use ULA addresses inside
> > an organization, or for a lab.
> > [...]
> > Implementing the non-normative suggestion from Section 10.6 of RFC
> > 6724 would in all likelihood result in making ULA usable for local
> > tests and even first steps in deploying IPv6.  ULA addresses would
> > only be used locally.  Existing IPv4 based Internet access would not
> > be impaired by adding IPv6 ULA.
> >
> 
> That does seem like it might make ULA more useful, yes.
> 
> Additionally, maybe we could clarify that the longest-prefix match rule
> does not apply to ULAs outside the same /48? I think that would fix
> the issue observed by +Ted Lemon <[e-mail]> in home networks:
> https://datatracker.ietf.org/meeting/113/materials/slides-113-6man-source-address-selection-for-foreign-ulas-00
> .

This is the reason for using a different label for the local ULA
/48 prefix.

> [...]

Kind regards,
Erik
-- 
Dipl.-Inform. Erik Auerswald
Gesellschaft für Fundamental Generic Networking mbH
Geschäftsführung: Volker Bauer, Jörg Mayer
Gerichtsstand: Amtsgericht Kaiserslautern - HRB: 3630