Re: draft-bourbaki-6man-classless-ipv6-00

[David Farmer <[e-mail]>]

On Sun, Jun 4, 2017 at 9:20 AM, <[e-mail]> wrote:

> > > So for example, here you are adamant that a device should not have to
> "ask
> > > the network" for more addresses. What about networks where there are
> other
> > > priorities, what if the operator of a network requires to track
> > > addresses/address usage for whatever reasons ?
> > >
> >
> > Again, the answers are in RFC 7934. See section 9.1 which goes into some
> > detail on address tracking. But basically: tracking via DHCP is insecure
> > unless you have L2 security, and if you have L2 security, you may as well
> > use that to track addresses.
>
> Tracking via DHCP is good enough in many cases, and already implemented
> in lots of support systems. L2 tracking has an extra cost. Guess which
> will be used?
>
> Steinar Haug, AS2116
>

On this point I have to agree with Lorenzo, tracking MAC addresses with
DHCP without the addition of L2 security to enforce it is pointless. What
about static assignment of addresses, without L2 security there would be no
way to prevent it.

We scrape Neighbor Discovery tables out of routers just like we do for ARP
tables in IPv4. It is independent of how the addresses are assigned, it
works with static assignment, DHCP, SLACC, and what ever else comes along.
The whole point of address tracking is accountability, having
accountability only for the people that follow a rule, what ever it is, is
kind of pointless, you need to track the rule breakers too.  Therefore you
need a tracking solution that is independent of address assignment.

Since we can track any address used, in most parts of our network we allow
SLACC for IPv6 address assignment, because it's the easiest to use in most
cases. That said I still think DHCP is a perfectly valid mechanism for
address assignment as well.

Thanks.
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