SME Pages


29th April 2003 Ian Wells

What is WOL?

Wake Up On Lan allows you to wake up another machine on the LAN. It is based on AMD's magic packet technology.
It can be used to run tasks overnight, waking up the machines as required.

A WOL client

I currently recommend ether-wake from Scyld Computing Corporation as I have been using it without problems for some time now.
Their site contains the source code, information about the program, and how to use it.

I compiled their program on a RedHat box, and it makes a tiny binary ether-wake.gz.
However I strongly recommend that you compile the program from source as it is a single C file, and compilation instructions are given at the end of the source file.

Example Use

It can be run from the command line, eg wake up the PC with MAC address AA:BB:CC:DD:EE:FF.

# ether-wake AA:BB:CC:DD:EE:FF

A more normal use is adding it to cron.

# Everyday at 5am wakeup the PC with MAC address AA:BB:CC:DD:EE:FF
0 5 * * * /usr/bin/ether-wake AA:BB:CC:DD:EE:FF

Further Information

I have tested this with Mitel SME Server versions 5.12 and 5.6, however it is not SME specific and should work on any RedHat machine.

If you use ether-wake.gz then you need to decompress the file, to give the binary ether-wake.

# gzip -d ether-wake.gz

This is Browser dependent, Internet Explorer downloads and uncompresses the file for you, but does not rename the file. The file is 19270 bytes uncompressed.

For more detailed information on this program read

If you have problems check that you have set up the target machine correctly:

  1. It may need a cable between the NIC and the Mainboard.
  2. It may need 'Wake Up On LAN' enabled in the BIOS

The target machine can be in Standby, Hibernation, or even powered off.

Other WOL clients

I have not tried these alternative clients myself as the Scyld client works well for me.

wol - Wake On LAN client From

Further Reading

A little Google will find many articles, here are some.

Magic Packet Top of the google search, with comprehensive links

AMD White Paper From the inventor's of the technology