MAC vs DUID issue

Valdinei Rodrigues dos Reis valmatrix at
Wed Apr 2 23:04:05 UTC 2014

Hi there.

Simon Hobson.

I run a tcpdump in our DHCP server, and analizing in wireshark, I noted
that both the DUID and the MAC Address are present in the message relayed
to server.

Steiner Haug

Hey, can you send me the patch ;)

Glen Eustace.

Nice. I'll give this advice to our support team. It will save us future

Of course it is valid to implement new ideias to a new protocol (DHCPv6),
but leave MAC mapping wasn't a good idea. Fortunately, after a long and
vigorous discussion, they (ISC) give up and released a version of DHCPv6
thas supports MAC mapping. But looks like they did it just because there
was so many voices asking for it, without taking the appropriate care.
In my oppinion, adoption of IPv6 is closely linked to a DHCP implementation
that in someway reminds implementation for IPv4, in a administrator point
of view.

2014-04-02 19:52 GMT-03:00 Andrew Hood <ajhood at>:

> On 03/04/2014 8:04 AM, Eustace, Glen wrote:
> > The duplicate DUID is a potential issue for anyone that is using any
> form of cloning to create system images, the resolution is in fact quite
> simple and our imaging team along with others have using it for quite
> sometime now.
> >
> > Assuming we are dealing with Windows computers, delete the DUID from the
> registry on the master image before cloning it. The first time the cloned
> image boots, a new unique DUID is generated.
> >
> Glen, you probably should say "a new highly likely to be unique DUID is
> generated".
> Andrew
> --
> There's no point in being grown up if you can't be childish sometimes.
> -- Dr. Who
> _______________________________________________
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