Saturday 17 March 2012

What is Wake On LAN ( Remote Wake up) Feature, how to enable Wake on LAN fearure, How to test Wake on LAN feature

Wake On LAN ( Remote Wake up)

Wake on Lan is a technology used to Wake up the PC/computer who is turned off. I came across this great technology when i was supposed to test whether our bridge/router allows the Magic packets to be forwarded or not.

WoL is a standard which enables to start the computer remotely even though it was switched off.

About the standard

Wake on LAN came from Intel and IBM Advanced Manageability Alliance formed on October 1996. This alliance introduced the technology in April 1997.

At almost similar time AMD  and HP came up with Magic Packet technology that allows the networked PC to go to completely asleep yet allows them to wake up after sending a specific data frame.

The actual standard document I am unable to found and i see both AMD and IBM claiming this technology as their own.

From standard and their implementation point of view its same. The magic packet is used to wake up the client.

Magic Packet

Magic Packet if you see in Wireshark it has  following format:

Ethernet2 header ( 14 bytes )
 ( Src mac address
   Destination mac address (Broadcast , FF:FF:FF:FF:FF:FF)
  Type: IP )
IP ( 20 bytes)
   ( Src IP , Dst IP (, version, header length, DSCP, total length, flags , fragment offset, TTL, protocol (UDP) )
UDP  (8 bytes)
    (Src port, dst port (9), length)
Wake On LAN, MAC
  (  Sync stream ( ff ff ff ff ff ff )
    MAC : 16 times MAC address

Requirements :

1) NIC with WoL capability

2) OS support ( Bios )

3) Tool or utility to send Magic packet

How To configure NIC

a) Go to -> Network connection Properties of the NIC card
b) Go to-> Advanced -> Search for  Wake on Settings-> Give value -> Wake on Magic or Wake on Magic & Directed.
c) Now go to Power management and check " Allow this device to bring the computer out of standby"

For other NIC cards the configuration settings are more or less same , so u can try finding similar options in other cards.

Bios Setting

Press F2/ Ctrl +S to go to Bios Setting. Search for "Remote Wake up" and make it "on"

Tools to generate Magic Packet

1) Ether-wake ( Linux utility ) to generate magic packet

2) A simple WB GUI utility

3) AMD utility

4) Requires Dot net framework