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Re: [dhcwg] DHCPv6 router option
At Wed, 11 Mar 2009 15:05:33 -0400,
Frank Sweetser <fs at WPI.EDU> wrote:
> > This is a major hot-button issue. People have extremely strong
> > opinions about it. It happens that although you and Iljitsch
> > disagree on what to do, you both have valid points. At the same
> > time, you appear to be talking past each other.
> >
> > What appears to be worrying Iljitsch, which you do not appear to be
> > concerned about, is that if a DHCPv6 client is receptive to this
> > option, it will trust it even when it is wrong, not just on your
> > network but on his. So adoption of this option affects Iljitsch just
> > as much as it affects you - he can't "opt out."
>
> Just to throw some more sand in the gears, there's also no guarantee that the
> RAs your clients are hearing are usable for them. Just last week, I had all
> IPv6 enabled clients in one subnet lose connectivity. After some digging
> around, it turned out that an XP box had began sending RAs, advertising its
> link local address as a default gateway. Once you allow fumble-fingered
> admins into the equation, not much is safe.
>
> When SOHO devices from Linksys and Netgear start appearing with IPv6 support,
> it's inevitable that those of us running EDU networks with dorms will have to
> deal with students plugging them in the wrong way around, just as they have
> been doing for many years. While this may be a "new" problem in that it uses
> RA to break the subnet, it's really not different from using DHCPv4 or ARP. I
> strongly suspect that in the end the switch vendors are going to have to
> create v6 analogues to the ARP and DHCP rogue server prevention features
> they've already implemented for v4.
This issue has been well discussed (though I'm not sure if we reached
a clear consensus). See draft-chown-v6ops-rogue-ra-03.txt and the
past discussions on that draft at v6ops. I'm personally not yet
convinced that this 'rogue RA' issue warrants the introduction of a
new router option for DHCPv6 (despite its clear disadvantage such as
conflicting information), but I also understand mileage varies very
much on this issue.
---
JINMEI, Tatuya
Internet Systems Consortium, Inc.