WAKE-ON-LAN

'Wake on LAN' (WOL, sometimes WoL) is an Ethernet computer networking standard that allows a shut-down computer to be booted remotely.

Contents

Technical details

System requirements - IBM PC Compatible

How it works

Magic Packet

Wake-on-LAN programs

See also

Additional resources

Technical details

System requirements - IBM PC Compatible

Wake on LAN (WoL) support is implemented in the motherboard of the computer. The motherboard must have a WAKEUP-LINK header onboard and connected to the network card via a special 3-pin cable; however, systems supporting the PCI 2.2 standard coupled with a PCI 2.2 compliant network adapter typically do not require a WoL cable as the required standby power is relayed through the PCI bus. Most modern motherboards with an embedded Ethernet controller also support WoL.

Wake on LAN must be enabled in the Power Management section of the motherboard's BIOS. It may also be necessary to configure the computer to reserve power for the network card when the system is shut down.
In addition, in order to get WoL to work it is sometimes required to flash this feature to the card. You can do this in Windows from the properties of the network card in the device manager, on the "Power Management" tab. Check "Only allow management stations to wake up the computer" to make sure it does not wake up on every single network activity that occurs. For Linux, there is a FAQ available concerning this issue.

How it works

The general process of waking a computer up remotely in a LAN can be explained thus:
The target computer is shut down, with power reserved for the network card. The network card listens for a specific packet, called the "Magic Packet". The Magic Packet is broadcast on the broadcast address for that particular subnet or the entire LAN. The listening computer receives this packet, checks it for the correct information, and then boots if the Magic Packet is valid.

Magic Packet

The Magic Packet is a broadcast frame, transmitted over port 0 (Historically the most common port used), or 7 or 9 (becoming the most common ports used). It can be sent over a variety of connectionless protocols (UDP, IPX) but UDP is most commonly used. The data that is contained in a Magic Packet is the defined constant as represented in hexadecimal: FF FF FF FF FF FF followed by sixteen repetitions of the target computer's MAC address, possibly followed by a four or six byte password.

Wake-on-LAN programs

There are a number of programs available that make use of Wake-on-LAN. Below is a partial list.
===Scripts===

★ WOL Python – a Python script.

★ Wakeonlan – a Perl script that sends magic packets.

★ Wake-on-LAN Tutorial, with PHP script

★ Wake-on-LAN PHP script
===Cross-platform===

★ Remotewakeup.com This site will wake up your computer

★ DSLReports.com - Wake Me Up - A free WOL packet generator that does not require Java. The tool will also remember your targets if you are a registered member.

★ java WOL – OS independent Java WOL utility which can be launched from browser.

★ microWoW A MIDP 2.0 MIDlet to power on your computer remotely. It can handle multiple profiles and it's multi-language. It's Open source under LGPL.

★ JWakeME A Java MIDlet based Wake on LAN utility. Requires a MIDP 1.0 compliant device.

★ HyperWRT - Firmware for Linksys wireless routers with WOL GUI.

★ DD-WRT - Firmware for Linksys wireless routers with WOL GUI.

★ Tomato - Firmware for Linksys wireless routers with WOL GUI.
===Source code===
Here you can find source code about WOL functionality for different languages and platforms

★ WOL .net - A VB.NET class to wake a device on the network.

★ Wake on LAN in C# - Sample code to do Wake on LAN using C#
===Microsoft Windows===

★ FUSION WakeUp on Lan - A free Windows application. Using FUSION WakeUp on Lan you can take advantage of turning on a remote PC through the net interface.

★ WOL - Magic Packet Sender 2007 – A free Windows application to store MAC addresses and send magic packets. Requires .NET.

★ Intellipool Network Monitor - Network and Server monitoring software that can start computers with WOL on a schedule.

★ AMD PCnet Magic Packet Utility - WOL application by AMD. It has a simple interface and a few nice features like group announcements and scheduling.

★ WakeUp - Free commandline wake-on-lan application for Windows.

★ PowerState - Free GUI wake-on-lan application for Windows that also includes Windows WMI shutdown. Build and save lists of PCs for repeated use.

★ WakeOnLan (Dipisoft) - A french freeware for wakeup, ping, restart, shutdown, close/lock session or hibernate distant computers. Does not require .NET runtime.
===Mac OS X===

★ Apple Remote Desktop - Multifunction tool with WOL capabilities

★ Wake550 - OS X adaptation of Wakeonlan script

★ WakeOnLan - A free utility and a Dashboard widget
===GNU/Linux===

★ EtherWake

★ Wakeonlan
===PalmOS===

★ PalmWOL

See also

★ Wake-on-Ring

Additional resources

★ Troubleshooting Remote Wake-up Issues - Useful WOL troubleshooting information from Intel

★ AMD's Magic Packet Technology white paper Publication# 20213

★ Wake-on-LAN white paper by Philip Lieberman describes the IBM / Intel alliance that created Wake-on-LAN

★ SmallNetBuilder Guide to Set up WOL