Duplicate Address Detection misfire?

Zaphod Beeblebrox zbeeble at gmail.com
Tue Jul 23 14:17:03 UTC 2013

Does that mean, then, that the only fix open to some people is to turn off
DAD?  I have another idea:

Require DAD to inspect the sending MAC address.  If the sending MAC address
is _our_ MAC address, then the packet is not an indication of a duplicate

On Tue, Jul 23, 2013 at 2:15 AM, Kimmo Paasiala <kpaasial at gmail.com> wrote:

> On Tue, Jul 23, 2013 at 8:44 AM, Zaphod Beeblebrox <zbeeble at gmail.com>
> wrote:
> > What to do when you don't trust the interface?  VMWare is obviously
> > emulating the hardware and their interpretation of what the hardware "is"
> > is possibly different from ours.
> >
> > If I boot single-user and tcpdump the interface, I see two transmitted
> > solicitations.  The kernel claims to have sent one.
> >
> > My concern: is the vmware interface reflecting the solicitation packet
> > because it is a broadcast packet?
> >
> > To determine this, I've gone over the tcpdump and pcap-filter man pages
> to
> > look for a way to only dump packets leaving from or arriving at an
> > interface.  Can this be done?
> >
> > If VMWare is reflecting the packet back, I'm curious as to how we can fix
> > this.
> >
> >
> That sounds exactly like my experience with DAD misbehaving on my
> Zyxel WAP3205 access point. It is reflecting  the multicasts (I hope
> that's the right term) so that any IPv6 equipment on the wireless
> network will think that its address is already in use. For the record,
> the client machines in my case are all OS X. Nice to know I'm not the
> only one with such problems.
> -Kimmo

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