9 October 2025 at 08:20, "Bjørn Mork via openwrt-devel" <[email protected]> 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 _______________________________________________ openwrt-devel mailing list [email protected] https://lists.openwrt.org/mailman/listinfo/openwrt-devel
