Hi!
Am 2017-08-15 um 11:43 schrieb Matthias Šubik:
let me have a guess ...
Let me guess a bit further...
On 11 Aug 2017, at 15:37, Gui Iribarren <g...@altermundi.net> wrote:
On 11/08/17 13:43, Christian Pock wrote:
...
For some reason, not all routers running olsr2 are reachable via IPv6. As far as we found out, this
is related to the setting "WDS bridge" on Ubiquiti-Antennas running AirOS 6 or earlier
(with must be enabled). So in case there's a node listed in the "olsr2 cloud", a missing
WDS-bridge-enabled setting could cause that the node is not available (highlighted blue in the
listing and map).
yeah, "WDS" must always be enabled on all bridges (in some AirOs
versions is called "Transparent bridge mode") or funny things happen in
IPv6 world
I don’t know AirOS, but I guess if disabled, it filters ethernet multicast,
this kills neighbour discovery, which is essential for normal IPv6 operation.
If you debug IPv6, please take into account the subtile differences between
IPv4 and IPv6 on layer two.
Multicast is not the only problem. Since AirOS is used in bridged mode,
you'd then have 'foreign' MAC addresses leaving the Wireless Interface.
This is, what WDS is usually for: it resembles 4-address mode, that
rewrites packets.
The effect of using a non-WDS-bridge would be, that ip neigh show would
list the neighbours correctly, but all of them will be STALE in the
first place.
If you try to ping them, you will fail, which will be represented by a
FAILED link in die neighbour table.
The funny thing is, that you could still ping6 the link local address
from a direct 1 hop neighbour.
So you may be lead to believe it's a mere multicast problem. But
debugging that, you will see, that proxying the multicast won't help.
The problem resides in NDP failing to resolve devices behind the bridge,
since it will only discover the wrong originator MAC - that is the one
of the AP on non-WDS-enabled devices.
TL;DR: ARP reachability is not v6 reachability.
Full Ack.
just a little reminder,
Matthias
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Best regards
Erich
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