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Wake a remote Mac behind a router
Authored by: padrino121 on Jun 10, '05 11:03:20PM

If the router implements port forwarding correctly any old port shouldn't allow a WOL packet into the network (read big security hole). WOL is a UDP packet sent to port 9 and with a proper router you would need to forward UDP/9 to the system you want to wake up.



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Wake a remote Mac behind a router
Authored by: spirp on Jun 11, '05 06:48:18PM

Actually, that's only partially true. A wake on lan frame can be embedded in any protocol and is nothing more than a specific stream of data. It's composed of 6 bytes 0xff followed by the MAC-address (ethernet address) repeated at least 16 times, ie

ffffffffffff001122334455001122334455001122334455
001122334455001122334455001122334455001122334455
001122334455001122334455001122334455001122334455
001122334455001122334455001122334455001122334455
001122334455

to wake a computer with the MAC-address 00:11:22:33:44:55. The first six bytes are for syncronization, and the rest identifies the computer. This can, as I said, be embedded in any protocol, or, for that matter, as a raw ethernet frame. UDP-packets seems to be the most common solution though, probably because it's simplicity.

Anyway, it ought be quite difficult to detect this kind of data stream (at least without false positives), and as far as I can tell, it's possible to insert a packet (ie TCP-packet) containing the magic string through a firewall. This, of course, may or may not be the case in the hint :)



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