On Wed, Sep 17, 2014 at 11:59:55AM +0200, Ignatios Souvatzis wrote:
> Hi,
>
> On Wed, Sep 17, 2014 at 10:14:31AM +0200, Mikael Abrahamsson wrote:
>
> > So, one interpretation would be that if the device hasn't subscribed to the
> > "all IPv6 nodes" multicast group, it's not an IPv6 node, and shouldn't
> > receive the traffic.
>
> Uh, no.
>
> the link-local stuff must never be snooped and blocked, because it is
> used to implement neighbour discovery and multicast routing protocols,
> multicast group managment etc.
>
> I think there's explicit wording for this - at least for the low /112 -
> somehwere.
I slightly misremembered.
RFC 4541 "Considerations for Internet Group Management Protocol (IGMP)
and Multicast Listener Discovery (MLD) Snooping Switches" says:
"3. IPv6 Considerations
[...]
In IPv6, the data forwarding rules are more straight forward because
MLD is mandated for addresses with scope 2 (link-scope) or greater.
The only exception is the address FF02::1 which is the all hosts
link-scope address for which MLD messages are never sent. Packets
with the all hosts link-scope address should be forwarded on all
ports."
-is
