Re: IPv6 Prefix Delegation through Network Manager

[dag dg <dagofthedofg gmail com>]

Thanks Thomas. Going into debug was able to point me in the right
direction. For those stumbling on this like myself, the
"ipv6.method=shared" refers to your *LAN* interface, not your WAN
interface. While this might seem intuitive to some, when I think
"shared" I think of the WAN though that is mostly a holdover from IPv4
conventions.

In an earlier fit of desperation I had tried setting the LAN interface
to "shared", but at the time ipv6 ICMP was unintentionally blocked by
the firewall which was preventing the negotiation with my ISP from
happening. I eventually figured it out that it was the firewall when I
switched to wide-dhcpv6 using the known working config I had used with
my old router, but I never went back to try setting the LAN interface
to shared.

After switching to debug I was able to see that the errors hinted at
NM trying to find an interface(device) other than my WAN to assign a
range to. The informational level message "no device to obtain a
subnet to share on <interface> from" sort of gives this away but by
itself can appear a bit cryptic, especially if like me you don't fully
understand how ipv6 works.

I think it would really help out if the documentation had a smidgen
more detail, even if it was just a "for example if you are configuring
a router for prefix delegation you would want to set your
LAN/local/whatever interface to shared mode". Maybe it's already
supposed to appear obvious but I definitely missed it, for what it's
worth.

Thanks again Thomas and thanks Vladimir; your earlier post was what
made me aware Network Manager began supporting prefix delegation in
the first place.

~dag
On Wed, Sep 5, 2018 at 8:11 AM Thomas Haller <thaller redhat com> wrote:
> On Tue, 2018-09-04 at 09:29 -0500, dag dg via networkmanager-list
> wrote:
> > There doesn't seem to be much documentation for Network Manager on
> > the
> > prefix delegation support. Any insight would be appreciated.
>
> Hi,
>
>
> it's not much documented, because there isn't much to configure about
> ipv6.method=shared. It's supposed to just work -- except when it
> doesn't.
>
> Could you provide a full logfile with level=TRACE enabled?
>
> See the hints about logging at
> https://cgit.freedesktop.org/NetworkManager/NetworkManager/tree/contrib/fedora/rpm/NetworkManager.conf
>
>
> best,
> Thomas