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

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