Question Help me understand this about WOL (Wake On Lan)

[TheFabled]

I have two Windows 11 Professional computers connected to my current network. But there was an issue with WOL on my main PC. I did every single thing i could think of to try and solve it, both in Windows and in BIOS.

It all came down to a single setting that had to be enabled, but why?

In Device Manager, and the network adapter, then in power management, there are three options.
1. Allow the computer to turn off this device to save power
2. Allow this device to wake the computer
3. Only allow a magic packet to wake the computer

The first two was always enabled, the third was not. After i enabled the third one, WOL worked.

The problem here, is the wording, the third option is seemingly a "sub category" of 2. And it contains the word "only". In my mind it made no sense that this had to be enabled, as it implies it limits the functionality, not expands it. But when i enabled the third option, i can now WOL my computer.

Another thing that makes no sense here, is that if I turn off 1.. Then 2 and 3 is greyed out, so you actually HAVE to enable "the computer can turn the device off to save power" for this setting to even be enabled, which makes absolutely zero sense.

Also note that i always had maximum performance enabled in Windows, there are no power saving enabled in the power plan. Not in BIOS either, and wake on LAN is enabled and always was both in BIOS and in Windows. But this one setting allowed me to WOL this PC.

Here is the strange part. My other PC on the same network, has always been able to WOL, but that does NOT have the third option enabled.

So why do I need that option enabled on THIS computer, but the other does not? My head spins at things like this. Nothing makes sense.

 

[Ralston18]

There are a number of settings and options involved.

The way to address and perhaps to understand it all is by comparing the two systems in more detail.

More needs to be known about network and power configuration settings of each system.

You can use powercfg commands and Powershell to delve into the details.

FYI:

https://learn.microsoft.com/en-us/w...ice-experiences/powercfg-command-line-options

https://woshub.com/wake-on-lan-windows/

https://learn.microsoft.com/en-us/t...setup-upgrade-and-drivers/wake-on-lan-feature

https://4sysops.com/archives/get-netadapter-managing-nics-with-powershell/

The Powershell Get-NetAdapter (or other "Gets") may prove helpful to understanding some difference(s) that may exist.

One advantage is that "Gets" do not change anything. And even if differences are found between the two systems you do not necessary need to change anything. Especially if just curious about the differences.

You can easily find additional links, tutorials, explanations, etc..

Be warned: some of them may cause even more headspinning...

 

[TheFabled]

Thank you for your reply Ralston18. After i wrote this, something came across my mind, there might be one single explanation to why my two computers act different. There is one setting in the BIOS i changed right before i changed that number 3 bit.

In the BIOS on my MSI Z790 Carbon Wifi (my main computer), i can set my Wake on timers to be controlled by either BIOS or OS. It is now set to OS, the other PC is likely BIOS. This is the only thing i can think of that makes sense.

This PC just simply refused to WOL even when all the BIOS settings were correct, i tried to find some hidden power saving setting that was enabled, but everything seemed fine, and all settings are what they are suppose to be (i think).

WOL should be made easier, a single option you can just enable or disable in the OS, and everything after that just be set up exactly as expected.

 

[ubuysa]

As I understand it ONLY a magic packet can wake the PC. That's because there may be lots of activity of the LAN but none of it may be for this PC. The magic packet is broadcast on the LAN but it contains the MAC address of the specific PC. This magic packet is what the wake-on-LAN feature is listening for.

https://www.twingate.com/blog/glossary/magic packet

 

[TheFabled]

As I understand it ONLY a magic packet can wake the PC. That's because there may be lots of activity of the LAN but none of it may be for this PC. The magic packet is broadcast on the LAN but it contains the MAC address of the specific PC. This magic packet is what the wake-on-LAN feature is listening for.

https://www.twingate.com/blog/glossary/magic packet

Yeah, it's just so weirdly placed and worded. It's categorized like a sub part of 2. Meaning 2 should already include magic packets. especially since 3 says only magic packet, implying all other methods will be ignored.

I have enabled magic packets like 4-5 different places on the PC, including BIOS and firewall. And this single option had to be checked for it to work. I haven't tested if WOL works if i disable everything else that i had enabled yet, but it's weird that you need to enable a feature in so many different places, when it could be one single button somewhere that just turns it on or off. It should be a simple standard.