Trouble with wakeonlan with Ubuntu 20.04

Solution 1:

If the cause is WoL settings not being persistent after reboot as explained in the previous answer, there is a simpler solution, which is posted here: https://askubuntu.com/a/1051894/883129

• Make sure you have ethtool and wakeonlan installed.
• Create /etc/network/if-up.d/wol_fix file with the following content:

  #!/bin/sh
  /sbin/ethtool -s [card] wol g
  

  where [card] is the name of your ethernet adapter, such as eth0, enp4s0 etc. (you can check this with ifconfig command).
• Then run:

  sudo chmod +x /etc/network/if-up.d/wol_fix
  

Solution 2:

I recently upgraded to Linux Mint 20. After re-installing the "wakeonlan" package I noticed it was not working. It turned out that upon shutdown, the wakeonlan option was being disabled. Here's how I worked around it.

On the computer you want to be able to wake up remotely...

Become root...

sudo su

Install the wakeonlan program on the computer you want to be able to wake up remotely.

apt install wakeonlan

Find your ethernet adapter, mine was called 'enp10s0' (usually called 'eth0').

ifconfig -a

Check the ethernet adapter to see what "Wake-on" is set to. See below link for diffent options and what they mean. https://www.thomas-krenn.com/en/wiki/Wake_On_LAN_under_Linux

ethtool enp10s0

Non-interactive creation of script which will set the "Wake-on" option to "g" which means "Wake on MagicPacket". For the next step (systemd) to work correctly, you must have the she-bang line included on the first line of the file.

cat >> /root/wol_fix.sh <<EOF
#!/bin/bash
ethtool -s enp10s0 wol g
EOF

Set correct permissions for the fix script.

chmod 755 /root/wol_fix.sh

Non-interactive creation of script which will run on boot to run the fixing script.

cat >> /etc/systemd/system/wol_fix.service <<EOF
[Unit]
Description=Fix WakeOnLAN being reset to disabled on shutdown

[Service]
ExecStart=/root/wol_fix.sh
Type=oneshot
RemainAfterExit=yes

[Install]
WantedBy=multi-user.target
EOF

Reload the systemd manager configuration.

systemctl daemon-reload

Enable to wol_fix service script.

systemctl enable wol_fix.service

NOTE: must reboot for the on-boot script to take effect. Or you can run the /root/wol_fix.sh script manually this time only before your next shutdown or reboot.

reboot

On computer you want to use to remotely wake up your other computer...

# [another_computer]$

Non-interactive creation of script to wake up computers on network. The "255" means only broadcast to a specific subset of the IP range on the local network.

cat >> /home/$USER/wakeuppc.sh <<EOF
wakeonlan -i 192.168.1.255 <MAC ADDRESS>
EOF

Add execute permisson for the wakeonlan caller script.

chmod +x /home/$USER/wakeuppc.sh

Solution 3:

Ubuntu allows Netplan for configuration. So, add the macaddress key and enable wakeonlan in /etc/netplan/00-installer-config.yaml. E.g.

ethernets:
  en01:
    match:
      macaddress: xx:xx:xx:xx:xx:xx
    dhcp4: true
    wakeonlan: true