Can Openwrt org apply for a (DUID-EN) org/enterprise number...?

[David Härdeman]

9 October 2025 at 08:20, "Bjørn Mork via openwrt-devel" <openwrt-devel at lists.openwrt.org> wrote:
> Looks like a misunderstanding of how DUID-LLT is supposed to work:
> https://github.com/openwrt/odhcp6c/pull/73#issuecomment-3382270139

I wouldn't characterise it as a misunderstanding. Yes, DUID-LLT's exist, but 
I think a DUID-EN has some advantages.

The first one is simplicity. With a OpenWrt-specific enterprise number, the
definition/generation of the DUID is up to the "vendor". And we could define
the DUID-EN as being simply <enterprise-number> + a random identifier of
suitable length/complexity (say, 128 bits), created on first boot, similar to
how ULAs are handled today by OpenWrt [1].

The DUID-LLT has the disadvantage that it is linked to a hardware address.
That means that an interface has to be picked on first boot, and the
MAC/hwaddr of the chosen interface will then be part of the DUID which will
be used/visible on all interfaces "forever". I can see that that could be
confusing to users. That's why I think DUID-LLTs are better suited for e.g.
a printer with a single ethernet port. Heck, even OpenWrt's own odhcpd digs
through DUID-LL/DUID-LLT identifiers and tries to convey meaning from them
(i.e. try to derive a MAC address from the DUID).

The DUID-EN is better suited to convey the purpose of the identifier, that
it is a permanent per-host identifier with no real linkage to any particular
interface and no particular meaning beyond that.

In that sense, the scheme that I'm thinking of is kind of similar to
DUID-UUIDs. This is also the approach used by e.g. systemd (they have
an enterprise number and generate a DUID-EN using the "machine-id", which
is generated on first boot [2]).

> But I guess the real cost is that OpenWrt would have to create a policy
> and internal registry of it's usage.  Otherwise it would pretty soon be
> unusable because of collisions.

I don't see why a registry would be necessary? Just create a random DUID
with enough bits that the odds of a collision are astronomical...?

Cheers,
David

(replying via webmail, I hope this won't get too awfully mangled...)

[1] https://github.com/openwrt/openwrt/blob/main/package/base-files/files/etc/uci-defaults/12_network-generate-ula
[2] https://unix.stackexchange.com/questions/743776/systemd-network-duid-iaid-and-dhcpv4-clientidentifier