[Dnsmasq-discuss] DHCPv6 and MAC

[Dan Williams]

On Mon, 2013-02-11 at 16:53 -0500, Gene Czarcinski wrote:
> On 02/11/2013 04:35 PM, Dan Williams wrote:
> > 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.
> Too bad.  I thought this might be a solution.
> 
> I really do not have multiple network interfaces on most systems and the 
> ones that do are manually configured.  So, I will just pick one( duid-LL 
> or duid-UUID) and use it for every installation where I need to have a 
> specific IPv6 address.

A DUID-UUID on a system with one interface should provide exactly the
same behavior as a DUID-LL on that system, no?  And are the systems you
run that have multiple interfaces that use DHCPv6 connected to the same
broadcast domain (eg, would use the same DHCPv6 server)?

Dan