Duplicate Address Detection misfire?

Kimmo Paasiala kpaasial at gmail.com
Tue Jul 23 06:15:12 UTC 2013

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.


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