On Wed, 2015-04-08 at 14:32 +0200, Martin Kletzander wrote:

I'm guessing the promiscuous modes plays its part in this field.  You
can try setting the interface to promisc mode manually using 'ip l set
$dev promisc on' and see whether that helps without starting tcpdump.
Also check sysctl -a | grep 'ipv6.*forward'.

Thank you for your answer. IIRC forwarding is only required for routing. I use bridge mode.
You are right - it's working with promiscious mode enabled.

Without:
2a01:198:200:8350:98ec:1708:c82e:a4fb dev br-lan INCOMPLETE

With:
2a01:198:200:8350:98ec:1708:c82e:a4fb dev br-lan lladdr 52:54:00:8e:b9:eb REACHABLE

Is it really required to be enabled all the time to make it work?

Cheers,

Stefan