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Waking computers from sleep...

Discussion in 'Win32' started by CommonTater, Aug 31, 2010.

  1. CommonTater

    CommonTater New Member

    Aug 31, 2010
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    New member... fwiw.

    I've been searching like crazy for a solution to a bizarre problem I'm having with some windows networking...

    The networking part is going fine. I'm using UDP to send commands from maching to machine on my lan and so far so good... Everyone's getting along nicely... so long as the machines are awake, my little setup works perfectly. Where the problem comes in is when the host machine is in sleep or hibernate mode...

    On Windows 7 the machine wakes up from the first DNS inquiry (getting it's IP from it's name), subsequent inquiries are buffered and do not wake it up. On XP DNS does not wake the machine but the first command packet I send wakes it up (and gets lost). Magic packets are not an option since I can't get the MAC address while the machine is asleep and there's no guarantee of any one machine always being at the same IP if I do, so databasing them is fruitless...

    The problem is these machines have to wake up when a stream of command packets begins arriving. I can send pings and wait for a response... but half the time the response never comes.

    So... comes the question... Is there a universal way to wake a machine?

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