host-identifier with IPv6
Ted Lemon
Ted.Lemon at nominum.com
Mon Mar 2 03:44:33 UTC 2009
On Mar 1, 2009, at 7:52 PM, Frank Sweetser wrote:
> And what if, rather than a fixed address, the address assignment
> were a
> dynamic one? In DHCPv4, the client would get a different address,
> but a
> number of people would be happy if it were legal for it to get the
> same one
> instead.
Two things. First of all, implementors are encouraged to provide
ways for things like DUIDs to be known by all the protocol agents that
might use them. But of course we have no control over what
implementors actually do.
Secondly, with DHCPv6, there simply isn't a shortage of IP
addresses. So if you set an artificial goal of absolutely never
having a client get a different IP address in the boot prom than in
the operating system, you may have trouble. But if your goal is
simply to notice that two clients are the same device, you can do that.
You can always come up with a scenario where you can show that DHCP
doesn't do what you want in that scenario. But each specific
behavior of DHCP is there for a reason. Rather than attempting to
engineer a different protocol that does precisely what you want, and
in the process opening yourself up to all the interoperability
problems we were trying to avoid when we wrote the spec, why not
simply figure out how to get what you need in the context of the spec
as written?
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