#423457 wakeonlan: extract MAC from IPv6 address

Package:
wakeonlan
Source:
wakeonlan
Submitter:
Rob Leslie
Date:
2010-12-19 04:09:03 UTC
Severity:
wishlist
#423457#5
Date:
2007-05-11 23:12:16 UTC
From:
To:
If a host has a resolvable IPv6 address, it would be nice to have an option
to automatically extract the MAC address from it.

Cheers.
#423457#10
Date:
2007-05-14 11:10:19 UTC
From:
To:
tags 423457 moreinfo ipv6
thanks

Hi,
option to work? I don't think a way exists to automatically deduce the mac
address from the IPv6 address in any case?

Please provide an example of how you would use this and how wakeonlan would
then work (or a patch :).

thanks,
Thijs
#423457#19
Date:
2008-04-05 07:33:51 UTC
From:
To:
Hi Thijs,

this is about the common way of autoconfiguring IPv6 addresses by creating
the host-specific interface identifier (the lower 64 bits of the address)
from the Ethernet address of the host. This can indeed be reversed,
so the request makes sense.

An example with the 'ipv6calc' program:

% host -t aaaa www.kame.net
www.kame.net            AAAA    2001:200:0:8002:203:47FF:FEA5:3085
% ipv6calc --showinfo 2001:200:0:8002:203:47FF:FEA5:3085
No input type specified, try autodetection...found type: ipv6addr
No output type specified, try autodetection...found type: ipv6addr
Address type: unicast, global-unicast, productive
Address type has SLA: 8002
Registry for address: APNIC
Interface identifier: 0203:47ff:fea5:3085
EUI-48/MAC address: 00:03:47:a5:30:85
MAC is a global unique one
MAC is an unicast one
OUI is: Intel Corporation

See RFC 2464 for details.

Cheers,
#423457#24
Date:
2008-09-03 09:10:50 UTC
From:
To:
hi!

 > this is about the common way of autoconfiguring IPv6 addresses by
 > creating the host-specific interface identifier (the lower 64 bits
 > of the address)from the Ethernet address of the host. This can
 > indeed be reversed, so the request makes sense.

That's right. But I think the question is if that is always possible.
The interface doesn't necessarily have to be autoconfigured. Maybe we
can think of a way to handle this cases.

regards
Thomas Prochaska
#423457#29
Date:
2009-04-23 10:12:11 UTC
From:
To:
The autoconfigured addresses have the bytes 0xFF and 0xFE
in the middle of the MAC address to fill the lower 64 bits.
#423457#38
Date:
2010-12-19 04:04:15 UTC
From:
To:
Hi,

I'm not sure this idea makes sense.

Where would someone obtain a list of IPv6 addresses that they wish to
send Wake-on-LAN packets to?  And if preparing such a list, would it not
be possible to compile an accurate list of MAC addresses at the time
(using broadcast pings, ICMPv6 neighbour discovery and/or ipv6calc)?


In many cases, a link-local (FE80:://64) IPv6 address can be mapped to
the interface's MAC address, but a notable exception would be Windows
boxes since Vista by default -- they randomise this:

* http://technet.microsoft.com/en-us/magazine/2007.08.cableguy.aspx

A properly-generated link-local address based on the interface MAC
should end with 'xxxx:xxFF:FExx:xxxx', whereas the random ones generated
by Windows probably won't.


Globally-routed IPv6 addresses are even less likely to map to a real MAC
address.  Hosts using IPv6 Privacy Extensions may periodically randomise
these on their outgoing traffic.  And globally-routed or site-local
addresses may have been statically assigned, or leased from a pool via
DHCPv6.

So it would seem this feature would rarely work.

Regards,