Re: IPv6 with Zen in the UK

[Mike Crowe <mac@mcrowe.com>]

Hi Bjørn,

On Saturday 01 April 2023 at 16:18:43 +0200, Bjørn Mork wrote:
> Mike Crowe <mac@mcrowe.com> writes:
> > Does anyone happen to have a working configuration using Debian pppd to
> > connect to Zen Internet in the UK with working IPv6? It looks like IPv6 is
> > expected to run over the IPv4 PPPoE connection. IPv4 is all working fine.

[snip]

> The other end could be expecting you to use the negotiated interface-id
> with that prefix.  But I believe it's more likely that they expect you
> to use DHCPv6 for address configuration.  Did you try that?  It's quite
> possible that they support DHCPv6-PD, assigning you a larger prefix.

It looks like they use DHCPv6 to delegate the LAN prefix(es), but I'd
(possibly incorrectly assumed) that this sentence from their email:

--8<--
/64 Neighbour Discovery (ND) Prefix. This is used to automatically
address the WAN interface of your Router, or if you are directly
connected without a router, the WAN interface of that device. This can be
configured using SLAAC.
-->8--

meant that I should expect to receive a RA with a /64 prefix for the WAN
interface address. (Earlier in the email is a /64 described as the "ND
prefix" along with a /48 described as the "delegation prefix".)

If they expected me to use DHCPv6 for this wouldn't they have set the M bit
in the RA?

> Finding good DHCPv6 clients with PPP support used to be difficult (the
> one from ISC only worked on ethernet).  I don't know the current status.
> One would hope that modern network managers like systemd-networkd or
> NetworkManager just works...

I did try running ISC dhclient and that would explain my lack of success. I
found mention of wide-dhcpv6-client, which appears to be in Debian, so I'll
have a look at that and also maybe dhcpcd which seems to be rather better
in my experience.

Maybe I should drag myself into the present and try systemd-networkd or
NetworkManager. I've just used Debian ifupdown up until now.

Thanks for all your advice. You've definitely given me some good pointers!

Mike.