Jul 25 2009

Wake On LAN

There is apparently going to be a bit more getting used to this new laptop.

The other day, before I went to bed, I put my new Dell Latitude E6400 into standby mode … I’m 99% sure I did this.

The next morning, however, when I went down stairs I found my laptop powered on.

That evening, before I went to bed I hibernated the laptop.

Once again, the next morning, I found the laptop powered on.

Obviously this is pretty odd.

So last night I tried an experiment … I put the laptop into standby mode and, within seconds, it resumed from standby.   I then put the laptop into hibernate mode … and 30 minutes later, it powered itself back up.

Intel NIC Power ManagmentI decided to see if Dell tech support would be of any help … and they were, after a fashion.   The tech I chatted with was a bit scatter brained, but he did get me to look at the NIC configuration for the laptop.

I usually have the “Wake On LAN” options enabled on my laptops … but I rarely use it.   And I’ve never had a problem with it.

The NIC on this laptop is an Intel   82567LM Gigabit adapter … and it has a property I’ve never seen before “Wake on Directed Packet”.

Enables this device to bring the computer out of standby or hibernation when a packet is sent directly to the adapter.

For example, any attempt to remotely access files stored on the computer will wake it.

I find this kind of odd … as this would make the laptop wake up from a standby or powered off.   I suspect that, in most organizations that has more than the most rudimentary network setup, this would ensure that any laptop with this option enabled would never stay off for very long.

I disabled the option and put the laptop into standby … it stayed off all night.

In the morning, I woke the laptop back up and hibernated it.   An hour later, it was still powered off.

Mystery solved!


    • alex on 28 Jul 2009 at 6:25 pm
    • Reply

    There are so called “Subnet-directed Broadcast” (http://www.uic.rsu.ru/doc/inet/tcp_stevens/broadcas.htm) that actually used to reach any remote network with WakeOnLAN over Internet.

  1. Alex: Yes, I’m familiar with Wake On LAN where it uses a specially formatted packet. In this case it was waking on any direct network connection … which would probably happen quite frequently in most networks.

    • alex on 27 Jul 2009 at 6:17 pm
    • Reply

    Useful link for Wake On LAN usage – http://www.wakeonlan.me. The service “Wake-On-LAN Online” is the way to remotely wake up PC over Internet. It can be used with any device connected to the Internet and allows simple wake up PC just with a link to the page of the site with necessary MAC and IP address.

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