wake on lan linux

Wake-on-LAN is an Ethernet networking standard that allows a server to be turned on by a network message. You need to send ‘magic packets’ to wake-on-lan enabled ethernet adapters and motherboards. WoL must be active in both: ethernet adapter and BIOS motherboard.

1 – Enable Wake-on-Lan on BIOS

2 – Install one Wake-on-Lan client. In Debian: etherwake. In CentOS: wol

apt-get install etherwake

3 – Send a network message to turned on a machine

etherwake 77:e5:49:f7:b7:c3

How to view if wake-on-lan is enabled on network adapter ( g [on] d [off] )*

ethtool eth0 | grep -i wake

*If the above command shows that wake-on-lan is disabled then maybe it is necessary to activate the same every time the machine starts.

– In some cases wake-on-lan is not active when the machine is turned on. Enable it in cron

crontab -e
@reboot /sbin/ethtool -s eth0 wol g

– Create a list with all mac addess of your network

nmap -sP && arp -a | sort -n -t . -k 4 | awk '{print "etherwake", $4, "#"$2}'

Some machines do not support Wake-on-LAN after a power failure. Use of an uninterruptible power supply (UPS) will give protection against a short period without power. A typical BIOS setting is AC back function which may be on, off, or memory. This last restores the machine to the state it was in when power was lost.

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