On Wednesday, September 29, 2021 10:22:27 PM CEST hw wrote:
> On Sunday, September 19, 2021 6:53:45 PM CEST Kenneth Porter wrote:
> > --On Sunday, September 19, 2021 3:02 PM +0200 hw <hw@xxxxxxxx> wrote:
> > > None of this is working because the server isn't running a DHCPv6
> > > server,
> > > and there seems to be no file in /var/lib/NetworkManager that would seem
> > > to be helpful.
> > >
> > > Isn't there a tool that creates the DUID and prints it? This can't be
> > > too difficult ...
> >
> > I found this thread that suggests that NetworkManager computes it every
> > time unless it's manually overridden:
> >
> > <https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/issues/135
> > >
>
> That might mean that I would need to extract the functions from the soruces
> of dhclient to make a program that prints DUID(s) for the machine you run
> it on. ... But that isn't so easy. Maybe I can find out how to create a
> DUID and write something in perl; it doesn't seem to be too complicated in
> the source.
>
> The comment is interesting:
>
> /*
> * The "best" default DUID, since we cannot predict any information
> * about the system (such as whether or not the hardware addresses are
> * integrated into the motherboard or similar), is the "LLT", link local
> * plus time, DUID. For real stateless "LL" is better.
> *
> * Once generated, this duid is stored into the state database, and
> * retained across restarts.
> *
> * For the time being, there is probably a different state database for
> * every daemon, so this winds up being a per-interface identifier...which
> * is not how it is intended. Upcoming rearchitecting the client should
> * address this "one daemon model."
> */
>
> I don't understand what the point of a DUID is which is /not/ a
> per-interface identifier. When I assign addresses via DHCP, I don't want
> them to end up being assigned anywhere else than to the interface they need
> to be assigned to. What is intended with these DUIDs?
>
Hm, ok, here's an explanation: https://www.juniper.net/documentation/en_US/
junose15.1/topics/concept/dhcp-unique-id-servers-clients-overview.html
IIUC, this means that I could create a DUID (of type 1) with an arbitrary time
value (Or where would I get the "correct" one?) and enter it into the
configuration of a static lease in OPNsense (or any other DHCPv6 server), and
it would be totally pointless unless I manage to force the client beforehand
to use this DUID to ask for an IP address and unless I can make sure that the
client always uses this DUID for a particular interface --- which isn't
intended because the DUIDs aren't supposed to identify particular interfaces.
Is that my lack of understanding or are these DUIDs really a rather stupid
idea?
And how are we actually supposed to set up static leases with DHCPv6?
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