Firstly (under ubuntu)

sudo apt-get install ethtool

Control your ethernet card is supporting wake on lan or not.

sudo ethtool eth0

if sth like that in output:

Supports Wake-on: pumbg

It’s ok.Than learn your mac address and write it somewhere.

ifconfig | grep HWaddr

Configure ethtool than shutdown your computer.

ethtool ­s eth0 wol g

To open your computer,  use a computer with same lan. Firstly install wakeonlan ( a simple program )

sudo apt-get install wakeonlan

And than open your comptuer

wakeonlan XX:XX:XX:XX:XX:XX

To disable it

sudo ethtool -s eth0 autoneg off