Wake up on LAN in Linux system

The raw materials are raising higher, a PC running 24 hours that can be used to remote control wastes too much electricity. With WOLfeature, we can inform the computer up only when we want to use it.

1. OS dependent

My server is built up by Shuttle XPC sk22g, as I know, most WOL feature can be configured via BIOS. Indeed, I found a wake up feature for the PCI card, but I used the onboard LAN chip. After asking the consultant, they said no setting in the BIOS, the WOL feature should be set by the software in the OS.

I had multi-systems in the server, Debian and Windows XP, in XP I can enable the WOL easily by the LAN driver. Sending the magic packet to it can really trigger to system up. But whenever I switch to the Linux system and power off the system, magic packet won't take effect.

I know that there is also a similar way to configure the NIC. Indeed, there is a ethernet tool called ethtool that can do this. Enable the WOL by "ethtool -s eth0 wol g" Now, your system has the ability the process the magic packet.


2. How to send magic packet

There are many applications either on windows or UNIX.

Wakeonlan is a very easy-to-use program in Linux, compile it, then run this "wakeonlan -i your.domain.name 00:13:49:XX:YY:ZZ", "00:13:49:XX:YY:ZZ" is the MAC address of your PC you want to wake up.


3. The PC is behind a router

Your router must support the port forward feature, try to forward UDP packet in port 9 to the PC you want to wake up.


4. After shutdown, it still not works

Try to check the halt script if it try to disable the network interface.
Below is my halt script in /etc/init.d/halt

#! /bin/sh
### BEGIN INIT INFO
# Provides: halt
# Required-Start:
# Required-Stop:
# Should-Start:
# Should-Stop:
# Default-Start:
# Default-Stop: 0
# Short-Description: Execute the halt command.
# Description:
### END INIT INFO

#NETDOWN=yes <-------- Comment this
NETDOWN=no <-------- Add the line
.
.
.
.
.
.
# Make it possible to not shut down network interfaces,
# needed to use wake-on-lan
netdown="-i"
if [ "$NETDOWN" = "no" ]; then
netdown=""
fi
ethtool -s eth0 wol g <-------- Add the line
halt ..

If your ACPI is enabled, don't forget to check the /proc/acpi/wakeup
PCI0 5 enabled
USB0 1 disabled
USB1 1 disabled
USB2 1 disabled
USB3 1 disabled
USB4 1 disabled
USB5 1 disabled
USB6 1 disabled
USB7 1 disabled
LAN0 5 enabled
AC97 5 disabled
PEXG 5 disabled
PEX0 5 disabled
UAR1 5 disabled

PCI0 should be enabled if you use a ethernet card on PCI slot, LAN0 should be enabled if you use a on board LAN chip.

Add some lines in the /etc/rc.local to enable them

echo -n "PCI0" >> /proc/acpi/wakeup
echo -n "LAN0" >> /proc/acpi/wakeup