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Setting up Wake-on-LAN: BIOS, Proxmox and NAS

With Wake-on-LAN (WoL) you turn on a computer or server over the network. Handy for a homelab that doesn’t need to run 24 hours a day: you leave the server off until you need it, which saves on power costs. It only works if three things are right: the computer supports it, it’s turned on in the BIOS and in the operating system, and the packet arrives on the right network. Below you’ll go through them.

How does it work?

Even when the computer is off, the network card keeps getting a little power and listens for one special packet: the magic packet. It contains six times FF followed by sixteen times the MAC address of the network card. It’s sent as a broadcast over the local network, usually via UDP to port 9. If the network card recognizes its own MAC address, it turns the computer on.

So you need the MAC address of the computer you want to wake up. Only see a list of devices? Use MAC address lookup to find out which manufacturer goes with it. On Linux you see your own address with ip link.

Step 1: turn it on in the BIOS or UEFI

Restart the computer and open the BIOS (often with Del or F2). Look for a setting with a name like:

  • Wake on LAN, Power On By PCI-E or Resume by LAN: turn on.
  • ErP or EuP Ready: turn off. If this is on, the network card no longer gets power in standby.

The names differ per manufacturer. A mini PC or laptop sometimes doesn’t have the option, or only with the plug in.

Step 2: turn it on in the operating system

Linux. Check whether the network card has WoL on. Replace eno1 with the name of your card (see ip link):

sudo ethtool eno1 | grep Wake-on

If it says Wake-on: g, you’re good (g means “magic packet”). If it says d, it’s off. Turn it on with:

sudo ethtool -s eno1 wol g

This setting disappears after a restart. Make it permanent with NetworkManager:

nmcli connection show
sudo nmcli connection modify "Wired connection 1" 802-3-ethernet.wake-on-lan magic

If you don’t use NetworkManager, put an ethtool line in a systemd service or in your network configuration. You make a service with the systemd service generator.

Windows. Open Device Manager, choose your network card and go to Power Management. Turn on Allow this device to wake the computer, and choose Only allow a magic packet to wake the computer. The advanced properties often also have Wake on Magic Packet: turn it on. Fast startup can get in the way of WoL from “off”; turn it off if it doesn’t work.

Proxmox. Proxmox is Linux, so the Linux steps apply to the host’s network card. In recent versions you can also enter a MAC address for Wake-on-LAN at the node, so that another node in your cluster can wake it up (pvenode wakeonlan). See also Proxmox tips and tricks.

NAS. With Synology and QNAP you’ll find the option in the admin interface, under the power settings. Turn it on there.

Step 3: send the packet

The easiest way is with our Wake-on-LAN tool: enter the MAC address and you get the command for Linux, Windows, Python and Home Assistant. You can do it yourself like this:

wakeonlan AA:BB:CC:DD:EE:FF
sudo etherwake -i eno1 AA:BB:CC:DD:EE:FF

The first command comes from the wakeonlan package, the second from etherwake. If you set it up in Home Assistant, you get a button to turn your server on from your phone.

From outside your home

A magic packet is a broadcast and stays within your own network. So it doesn’t work directly over the internet, and forwarding a port to the broadcast isn’t wise. The proper solution: connect to your home network through a VPN and send the packet from a device that’s always on, such as a Raspberry Pi. How to set that up is in WireGuard or Tailscale.

Do you have multiple networks (VLANs)? Then the broadcast doesn’t cross the boundary. Send the packet from a device in the same network as the computer you want to turn on.

Not working?

  • Check the MAC address. A server with multiple network cards only listens on the card where WoL is on.
  • Is the computer really off? A computer that’s asleep or hibernating sometimes responds differently from one that’s completely off. Test both.
  • Is the light on the network port on when the computer is off? If not, the card gets no power: check ErP in the BIOS.
  • Wifi almost never works for WoL from “off”. Use a cable.
  • Test first from the same switch, in the same network, before you try it over a VPN.
  • After a power outage a computer sometimes has to be started up normally once before WoL works again.

When the server is on, you can also let it sleep or shut it down properly again. Wake-on-LAN fits well with a frugal setup: see Frugal and quiet.