[Dnsmasq-discuss] DHCPv6 and MAC

[Dan Williams]

On Mon, 2013-02-11 at 16:29 -0500, Gene Czarcinski wrote:
> On 02/11/2013 04:12 PM, Dan Williams wrote:
> > See my reply to your other mail about this; I see what you're saying
> > now, and I think we can push for having whatever generates machine-id
> > (often systemd) pull that information from firmware/hardware rather than
> > generating it randomly.
> Success!  Thank you.  That does scratch my itch.
> 
> So long as it does not vary, I can plug it into dnsmasq with fixed IPv6 
> addresses and it will work.

Well, it turns out that machine-id is confusingly named, and that it's
actually the "install id" and is meant to change whenever the OS is
reinstalled.  So we're kinda stuck here; either we try to follow the
standards to the end of the earth and start
parsing /sys/class/dmi/id/product_id (which apparently is often
1234567890) or we just go off machine-id and understand that
reinstalling the OS on the same hardware will change the DUID.

My believe is that using DUID-UUID generated from /etc/machine-id is
more standards-compliant and less error-prone than using DUID-LL or
DUID-LLT though.  And, of course, it can always be overridden.

Dan