IPv6 DUIDs

David W. Hankins dhankins at isc.org
Thu Oct 1 18:07:41 UTC 2009


On Thu, Sep 17, 2009 at 09:57:24AM +1200, Eustace, Glen wrote:
> I received no comments from anyone as to whether doing this was not a good idea or not.  I would still be keen to hear from anyone that can think of any objections.

my main point is if you're going to have a fixed time value, you may
as well omit the time value entirely and use a DUID-LL rather than
the default DUID-LLT (DUID's have three distinct formats).

you should see the leading octets like this in a DUID-LLT;

	00:01:00:01

then 4 bytes of time, then 6 bytes of ethernet mac.

instead, a DUID-LL starts out;

	00:03:00:01

followed by 6 bytes of ethernet mac.  the third and fourth octets,
'00:01', in both these cases is the 'htype'.  1 is just ethernet.

example; sending a DUID-LL (a different DUID-LL on every interface)
with ISC dhclient;

	send dhcp6.client-id = concat(00:03:00, hardware);

-- 
David W. Hankins	"If you don't do it right the first time,
Software Engineer		     you'll just have to do it again."
Internet Systems Consortium, Inc.		-- Jack T. Hankins
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