wake on lan / wol with linux in IPv6-LAN (without IPv4)

[Tom Hill]

On 17/09/14 11:07, Ignatios Souvatzis wrote:
>    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."

Forgive me if I'm missing some crucial element here, but wouldn't it be
possible to:

(1) assign new multicast address for v6 WoL (and not use ff02::1)
(2) require that traffic for this address is forwarded /like/ ff02::1

This means that only hosts listening for IPv6 packets on this multicast
group would care about the WoL traffic sent (giving the stack plenty of
chances to ignore it if it isn't WoL-capable), and that any station
awaiting WoL instructions will not have to emit any sort of MLD
subscription.

Whether the ability to send MLD packets is severely constrained by the
standby power of the NIC, is another matter entirely (and one that I'm
not qualified to comment upon).

My main concern in piggy-backing on ff02::1 for its inherent "passive"
ability, are the associated management/security concerns on a mixed-use
LAN segment. For instance, basic L2 filters could then easily block the
use of the new group, on ingress ports that have no business sending
such WoL commands.

-- 
Tom