wake on lan / wol with linux in IPv6-LAN (without IPv4)
p.mayers at imperial.ac.uk
Mon Sep 22 11:51:37 CEST 2014
On 22/09/14 08:42, Ignatios Souvatzis wrote:
> But I imagine people might want to wake every host once a night
> and run some backup or software update remotely; so unconcerned
> machines would see, say, one or two packets times the number of
> sleeping machines per night. How many hosts do you have per broadcast
> domain? more than 2**8?
We have some IPv4 /21 with >2**10 hosts actually. They're managed
machines and it's largely to work around the IPv6 address space wastage.
It's marginally suboptimal from a "size of failure domain" PoV, but
we've never actually had the sort of problems this can lead to in
theory, and the alternative was worse.
Obviously single /64 IPv6 (bliss!)
> There's another consideration: if you do have the need, due to huge
> broadcast domains, nobody prevents you to make your machines
> subscribe to a locally assigned multicast address and send your
Erm... while they're asleep? Doubtful that would work - most network
stacks end up dropping then re-initialising the ethernet link when they
go to sleep, so MLD snooping state is likely to be cleared, and absent
something like AMT/vPro (which comes with it's own IPv6 hassles ;o) to
join the group in the sleeping link-state...
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