One of the most common myths and misconceptions around power management is wake on lan and it’s shortcomings.  IT administrators still mistakenly believe that wake on lan is not ‘enabled’ on their network and hence power management is not an option as they have no ability to wake devices for patching purposes.

Let us examine the facts.  The following is true:

• Wake on lan requires the broadcast of a magic packet (the wake up request)
• The magic packet is broadcast via UDP and where the network does not allow these broadcasts, wake on lan (in its native form) will not work
• Wake on lan requires that the NIC is enabled to receive the magic packet in the bios

In the majority of secure networks, UDP broadcasting is rightly disabled as it is a huge security risk and opens up threats around denial of service attacks.  THIS HOWEVER DOES NOT MEAN THAT YOU CANNOT GET WAKE ON LAN TO WORK, YOU JUST NEED THE RIGHT TOOLS.

Power management tooling allows you to overcome these limitations by doing some clever things without any changes to network security whatsoever. 1E’s NightWatchman for instance has the concept of ‘last man standing’.  This dynamic solution ensures that at least 1 pc in each subnet stays on constantly and acts as a proxy for the magic packet request.  There is no configuration or ‘nomination’ required, the solution does this out of the box.  If the agent gets powered down by the end user it will either auto reboot or an alternate agent will be used.  Hence you can shut down and wake up until your heart is content, achieving significant cost savings as well as actuall improving patching success rates.

Configuring the NIC to allow wake ups is also relatively simple although most modern devices come with this enabled already due to Energy Star compliancy.  NIC’s can be enables through a multitude of tooling, much of which is available free from the variousl hardware vedors.

So in short, wake on lan, yes you can!  Don’t think otherwise.

Tags: NightWatchman, PC Power Management, power management, wake on lan

This entry was posted on Tuesday, June 8th, 2010 at 1:58 pm and is filed under Information Technology. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.