Wake on LAN
From GroovixWiki
To use Wake on LAN (WoL) type the following command in an xterm window: wakeonlan [MACaddress]. If the wakeonlan application is not already installed on that particular machine type apt-get install wakeonlan before trying again.
Note: WoL magic packets cannot be routed past a layer-2 link, WoL will only work if the computer sending and the computer receiving are on the same IP subnet.