Re: Understanding IPv6-PD over PPPoE

[Andrei Borzenkov <arvidjaar gmail com>]

On Wed, Jun 16, 2021 at 12:03 PM Steve Hill <steve opendium com> wrote:
> On 16/06/2021 09:43, Andrei Borzenkov wrote:
>
> > It is explicitly prohibited to assign any IA_PD prefix to the same
> > interface via which this was obtained.
> >
> >                                                the requesting router MUST
> >     NOT assign any delegated prefixes or subnets from the delegated
> >     prefix(es) to the link through which it received the DHCP message
> >     from the delegating router.
>
> [...Which is from RFC 3633]
>
> That's a pain.  It basically makes it impossible for a single-NIC
> machine to connect to an ISP that is only responding to IA_PD.  (Well,
> you can obviously set up a dummy NIC, which can be assigned a prefix,
> but that's a kludge).
>
> I can see why you wouldn't want a whole /64 to be assigned to an
> ethernet interface that received the DHCPv6 Advertise, but it does feel
> reasonable to be able to *optionally* assign a /128 to the
> point-to-point link that received the DHCPv6 Advertise, if there is no
> other way to assign a global address to it.


The default and standard method to assign IPv6 address is SLAAC.
DHCPv6 is optional. You need to investigate why SLAAC address was not
assigned.