Why my computer wakes up from the network card?

Question

I've noticed my computer receiving a wake signal from my network. I am on a LAN with only few devices connected on it: printer, smart phones, nas, router + few other computers...

I checked the status of the last wake with power config:

C:\>powercfg /lastwake
Wake History Count - 1
Wake History [0]
  Wake Source Count - 1
  Wake Source [0]
    Type: Device
    Instance Path: PCI\VEN_8086&DEV_1503&SUBSYS_849C1043&REV_05\3&11583659&0&C8
    Friendly Name:
    Description: Intel(R) 82579V Gigabit Network Connection
    Manufacturer: Intel Corporation

So I disallowed my network card to wake my computer.

My question is why do I receive wake signals from my network? What can be the origin?

Answer 1

I would focus on devices that are on the same link. The best way to check for devices is to look on each possible device for some software/setting that will end the packet. Note that you should not restrict your search to only other devices. (The drive that is woken up might be getting awakened for some other cause, like a scheduled event, and coincidentally send WoL.)

If you don't find the cause from there, your best bet may be to leave the computer on, intentionally, and run a network sniffer that can perform packet capturing. (I would expect TCPDump can do this, and also WireShark. However, know that WireShark has been known to have some security issues, so this may not be the best option if you're on a network where an attacker might be able to communicate with the computer that wakes up.)

That sniff/capture ought to be able to tell you the MAC-48 address of the device sending the packet. Then look up at MAC address lookup to find the device manufacturer.

If that doesn't work, swapping parts might help. Note that WoL can be sent by things other than computers. For instance, routers have been known to have an option to send a WoL packet.