PC World

The Magic Packet-How Wake on Lan Works

WoL-enabled computers essentially wait for a “magic packet” to arrive that includes the NIC’s MAC address in it. These magic packets are sent out by professional software made for any platform, but can also be sent by routers and internet-based websites. The typical ports used for WoL magic packets are UDP 7 and 9. Because your computer is actively listening for a packet, some power is feeding your network card which will result in your laptop’s battery draining faster, so road warriors should take care to turn this off when you need to eke out some extra juice.

magic-packet

Magic packets are usually sent over the entirety of a network and contain the subnet information, network broadcast address, and the MAC address of the target computer’s network card, whether Ethernet or wireless. The above image shows the results of a packet sniffer tool used on magic packet, which brings into question exactly how secure they are when used in unsafe networks and over the internet. On a secure network, or for basic home use, there shouldn’t be any practical reason to worry. Many motherboard manufacturers often implement software along with WoL capabilities to offer hassle-free or largely configuration-free usage scenarios.

Enabling WoL on Your System

Bios: Most older computers and many modern ones have their WoL settings buried in the BIOS. Depending on your system, you need to hit Escape, F2, or Delete to get into the BIOS, but if you’re not sure then you should check your system’s documentation. Once you’re in, check under Power Management or Advanced Options or something of that sort.

hystouwol

On this Hystou mini pc FMP04B-i5-4200U bios, wake on lan setting is in chipset. Many computer, however, do not have a BIOS option. Fortunately, this doesn’t mean that the capability isn’t there, it just means we need to go through the operating system to enable WoL.

Windows:Click Start, then search for and open the Device Manager. Find your networking device in the list.

win1

Right click on it and go to Properties, then click on the Advanced tab.

win2

Scroll down in the list to find “Wake on Magic Packet” and change the Value to “Enabled.” You can leave the other “Wake on” settings alone. Click OK when you’re done.

OS X: Open up your System Settings and choose Energy Saver.

energysaver

Under the Options tab, you should see “Wake for Ethernet” or something similar. This enables Wake-on-LAN.

Linux:

Ubuntu has a great tool that can check to see if your machine supports WoL and can enable it. Open up a terminal and install “ethtool” with the following command:  [sudo apt-get install ethtool]

You can check your compatibility by running: [sudo ethtool eth0]

If your default interface is something else, substitute it for “eth0”.

wol-ubuntu

Look for the “Supports Wake-on” section. As long as one of the letters listed is “g,” you can use magic packets for WoL. To enable this option, use the following command: [sudo ethtool -s eth0 wol g]

This should take of it. You can run the command to check and see if it’s enabled now. Look for the “Wake on” section. You should see a “g” instead of a “d” now.

wol-ubuntu-2

Sending WoL Magic Packets: To send out WoL requests, you have a cornucopia of options available.

depicus

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