Initially, this was feature-gated, but has been requested
to be changed to be unconditional, see PR 3488 for reasons.
When filtering is enabled, it intercepts and drops silently
ipv6 packets, possibly somewhere around
smoltcp::iface::interface::ipv6 lines 36, 44 in current head
sha e9b66eadaeacef758ebc4a12378f8d2162144cf4
With filtering disabled (this patch), packets are received
and communication over ipv6 is possible, neighbor discovery works.
related: #2496
Signed-off-by: Krzysztof Królczyk <Krzysztof.Krolczyk@o2.pl>
e93ac532ac