How does Wakeup on lan work?

(imported topic written by gcibirch91)


We are in the process of moving away from WSUS to patch all our workstations using BigFix. We also want to use the Power Management module as well. Part of this will be to put clients into hibernation if they have been left on.

How does WOL work if the client is in hibernation? does it turn it on or do we have to put clients into standby? the reason I ask is we may look to patch our computers during the night and then reboot them. we would therefor need WOL to wake up all computers ready for the patch run to start. is this possible or am I misunderstanding the WOL feature.


(imported comment written by Lee Wei)


The table on this link is useful as a guide to the various levels of shutdown and what features will work.

So yes, a PC in hibernation mode can resume using wake-on-LAN assume that other required conditions are met (BIOS settings etc).

Lee Wei

(imported comment written by BenKus)

Hey gcbirth,

An option that you might consider is using a “scheduled wake-up” using BigFix Power Management. This will allow the computer to wake-up at a specific times each night (or whatever schedule you want) and then it can be updated and go back to sleep.

With scheduled wake-ups, you don’t need to worry about wake-on-lan (except as a secondary measure).


(imported comment written by gcibirch91)

Thanks guys.

Yeah was more leaning towards the scheduled wake-up option in bigfix. Just to confirm this should wake up computers from hibernation or standby. Daft question but presume it won’t wake up a machine that has been shutdown unless bios settings changed?

(imported comment written by gcibirch91)


Using the wake-up schedule option what is the best practice here as I do not want to send messages to the servers.

(imported comment written by MattBoyd)

Hey gcibirch,

One of the things you should ask yourself is if you really need to use hibernation on your computers. With S3 standby enabled, power savings are close to the same as a computer in hibernation (or powered off). Any additional savings that hibernation does provide will usually be offset by poor user experience because resuming from hibernation takes much longer than resuming from standby. For desktop computers in general, I believe that standby is the way to go.

I’m fairly certain that a machine with an ACPI-compliant motherboard can be woken up on a schedule from hibernation, but I have not tried it. I’ve used an application called WakeupOnStandby, which claims to be able to do it: . I’ve also read online that Windows Task Scheduler can do it.

Will either of these be able to wake a machine that is shut off? Probably not. However, I know of at least one person who wakes machines from a powered-off state via WoL, which may be one reason Ben mentions that WoL should be used as a secondary measure.

Regarding best practices, my number one best practice is to find a way to deal with “PC Narcolepsy” before deploying your power management solution. Details about PC Narcolepsy (and a fixlet that can help resolve the issue) are available here: .

(imported comment written by gcibirch91)

Thanks Boyd I will do some more testing on standby and see if that makes a difference.

(imported comment written by DennisA91)

I found the information referenced by Lee Wei at to be most useful synopsis of Windows WoL options. When I visited the site, I saw a note that Visionsoft, the company that authored the document, is in voluntary liquidation in the UK, and that much of their website has been disconnected.

You might want to get a copy of the material at this link before it is no longer accessible

(imported comment written by BenKus)

I added a table for some useful WoL/Power info at:


(imported comment written by georgewilliam8891)

LAN is platform-independent, so any application on any platform that sends magic packets can wake up computers running on any platform. It is not restricted only to LAN traffic.

  1. First of all the computer should turn off, with power reserved for the network card, but not disconnected from its power source. Then the respective network card listens for a specific packet containing its MAC address, called the magic packet, broadcast on the broadcast address for that particular subnet.

  2. While listening, computer receives this packet and the network card checks the packet for the correct information. If the magic packet is valid, the network card takes the computer out of hibernation or standby, or starts it up.

  3. In order for setting up LAN to work, parts of the network interface need to stay on. If it is not needed, disabling it may reduce power consumption slightly while the computer is switched off but still plugged in.