[SLUG] Wake on Lan

[Fintan Gaughan]

On 26/02/07, Mike Bennett <mikeyben at gmail.com> wrote:
> On 2/26/07, Stephen O'Neill <soneill84 at yahoo.co.uk> wrote:
> > To elaborate a tiny bit on what Mike says, to help with your internet
> > searches, passing a WOL packet to the internal network is known as
> > "broadcasting". With NAT routers which I have come across you need to
> > setup firewall rules to pass packets to a specific IP address (e.g.
> > 192.168.0.2) - it is not possible to use a broadcast address (e.g.
> > 192.168.0.255).
>
>
> Some routers will allow you to pass a MAC address with the command to
> broadcast a packet and therefore direct the external packet to the
> appropriate internal machines. The router, if it supports remote WoL,
> should transform the incoming request into a broadcast to be sent over
> the internal network anyway, because there will be no internal IP
> address to pass the data to if the computer is powered down.
>
> WoL packets break down into an initial data "wake-up" call or "magic
> packet". This is normally just a burst of solid data to alert all
> machines with WoL activated to listen out for the next bit.
> The second part of a WoL is the broadcasting of the MAC address of the
> target machine to wake up. This is normally repeated 8 or 16 times and
> on some systems is then followed by  a termination packet (although
> this is not required).
>
> All machines in broadcast range of the originator will then check the
> MAC address against the MAC address of the NIC recieving the data. If
> it matches, then the machine will be booted.
>
> Therefore it is not possible, as far as I am aware, to do it without a
> router supporting WoL as you will have to pass the MAC address of the
> target machine to the router.
>
> The other option for this is to have an internal machine that is
> always on and can do the same work as the router, therefore you can
> use the same method (of broadcasting to the target MAC) from an
> internal machine, and don't have to have a router that supports WoL as
> you can just get or write a server/client to pass the data through to
> the designated "always-on" internal machine as a standard protocol
> over TCP/IP.
>
> Hope this is helpful.
>
> Cheers,
> Mike
>

Thanks everyone for usefull help :-)

I suspect its my router causing the problem looks like  I could get my
wife to turn the computer on when she is at home.

Regards,
Fintan