host-identifier with IPv6

Sten Carlsen sten at s-carlsen.dk
Mon Mar 2 23:30:35 UTC 2009


Well, I don't run any kind of big shop, but I have a couple of comments
from the side line:

Ted Lemon wrote:
> I applaud you for your optimistic view of DHCP implementors.   Here's
> the problem.   The Mac address *can't* be a unique identifier, because
> it can change, either because of hardware changes or because the
> address prom gets reflashed.   Or, on some types of hardware, because
> there is no fixed hardware address.   But we want a stable, unique
> identifier.   So we get our uniqueness from a combination of the Mac
> address and the time, because it would take a fairly surprising
> coincidence to make both of them be the same on two different nodes,
> and then we keep that address in perpetuity.
So why do you think this DUID would be the same unchanged during a
device's lifetime? I upgrade my OSes regularly and for several reasons I
usually do so with a full new install, not an upgrade. Quite often I
also switch the disk for a bigger one.

The way I see this is that I will have to redo my DNS settings every
time, since the DUID is new, the DNS will point to something old and no
more existing.

Why did you want to select something significantly less stable than MAC
address?
>
> But we, the authors of the protocol, do not and cannot control
> hardware vendors.   Even if we could spec out how hardware should work
> in the future, we can't say how it should have worked in the past,
> because the past is already written.   There is plenty of hardware out
> there that can do DHCPv6 but that was shipped before DHCPv6 became
> something anybody except a few geeks at IETF like me gave a damn about.
Agree, IPv6 MUST be just a SW-upgrade, otherwise it will never be accepted.
> So like it or not, your solution has to be adaptive.   It would be
> nice if it were otherwise, but complaining about it isn't going to
> change it, and believe me, if there were a way to do what you want in
> the protocol spec, we would have done it.   It's easy to postulate
> perfect solutions in a vacuuum (say that three times fast), but you've
> been on this mailing list and doing DHCP long enough to know just how
> likely it is that vendors will even read the spec, much less follow it
> if it's inconvenient.
I still think most people, maybe specially the ISP guys want a label
(with a bar code) on the box that they can scan when the ship the
package the their customer. Why would they want anything that only gets
initialised once the power is turned on? How do you expect them to
capture that info once the device has been put into the mail?

-- 
Best regards

Sten Carlsen

No improvements come from shouting:

       "MALE BOVINE MANURE!!!" 




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