Greetings! So recently, i spent a few hours coding software. After i was done and i shut off my pc, i noticed both of the ethernet lights were on and blinking. Does this mean that Microsoft is sending data to their servers before the PC fully shuts off? I am scared that this might be the thing it does. How can i get rid of this issue? I have no idea if it’s related to Windows or the PC itself.
You computer has a feature for Out of Band management. Either WoL as others have mentioned or vPro(Intel), iLon(HP), iDrac(Dell), as well a few other less popular systems depending on who makes your mainboard or NIC.
This leaves the power on to the network card so that it can be used even with your computer off. It does not have access to your normal computer in the this case. Just the ability to turn on/off the system and sometimes options to update BIOS/UEFI firmware and send a console image to either a client or browser.
The lights are blinking because broadcasts packets from other devices on your LAN are sent to every device. This is normal and expected behavior.
Just building off of this, modern computers are chatty as heck and there’s just constantly little bits of chatter spamming out on LANs. This is normal and expected behavior
More rarely: some poorly configured USB controllers can actually provide enough backwash power to the motherboard that some LEDs still blink, like the Ethernet indicators.
I ran into this myself, I notice the lights being on, and they stayed on when I unplugged the computer. Took me a good 5m of debugging to figure it out.