Networking

Using Magic Packet Utility to send wake on LAN commands

Using wake on LAN technologies is frequently reserved for systems management software, but it is handy to know how to do the command. IT pro Rick Vanover shows how to perform the magic packet boot.

Many PCs and servers come with the ability to perform Wake-on-LAN (WoL) boots. For network adapters that are connected to the network while the device is powered off, WoL supported systems can be sent a remote power-on command. At one point in my practice, I disabled this on critical servers in favor of managing the servers with something like the Dell DRAC or HP iLO device. I still feel it useful to know how to perform this command, so I’m going to walk through using the AMD Magic Packet Utility.

Installing the software is straightforward, and the tool will perform a scan of the subnet mask to enumerate the hosts. The result of the scan on my lab network is shown in Figure A. Figure A

Figure A

Once the network is enumerated, the magic packet can be sent to a specific MAC address. This is either known ahead of time or determined by the scan done in the step above. To send the magic packet, simply enter the system’s MAC address into the window, as shown in Figure B. Figure B

Figure A

At that point, the magic packet will be sent over the current subnet to the destination MAC address and the system will power on. See this TechRepublic discussion for how to configure WoL packets to be sent to different subnets. WoL behavior will depend on a number of factors, namely the system hardware and network configuration. Network interface support or even the network BIOS or ROM may affect WoL behavior, as will the system BIOS.

On the other hand, should this even be enabled on networks? Chances are WoL packets are bad, as there is no security in the mechanism, making use of the feature difficult in certain environments. Do you forbid WoL support and disable it? I can totally see the point in doing so; share your comments below on WoL and the magic packet.

About

Rick Vanover is a software strategy specialist for Veeam Software, based in Columbus, Ohio. Rick has years of IT experience and focuses on virtualization, Windows-based server administration, and system hardware.

8 comments
justintjacob
justintjacob

Our Company implement web based wake on LAN ,because our users always need remote connection to their desktop PC and they never shutting the machine on off-week days and we will lost lot of energy ,so we are hibernate PC after 10 mt using group policy and provide a web based link to the users to power on the machine here are the steps to install web based wake on LAN. The system requirement is One windows machine server Os or Client OS with IIS, Dotnet Framework 2.0 and Sql Express.here is the steps 1.Download Wakeonlan Application from this site http://spidersoft.in/Windows/Network-Internet/Remote-Computing/Web-Based-Wake-On-Lan_273.html 2.Detailed Installation found this site http://computech.in/2013/06/web-based-wakeonlan-how/

robd
robd

WOL software like fusion wol has password input box,for password protected BIOS on systems. If you have a bios password enabled wol and magic packets cannot wake laptop and will not work unless the utility has password feature. Just some other simple security measure you can take beside the ACLs on switches and routers along with other network management / security techniques

scoopboys
scoopboys

Is there value to Wake-on-LAN? Heck yes, especially at a time when we are being asked to power off PCs for energy savings. The risk is not that PCs will be powered on, though. The risk is that you need to enable directed IP broadcast, which can be used maliciously. However, you can securely enable using Access Control Lists. You can limit (at the router, using ACLs) the devices (IPs) from which the router will allow and forward IP broadcasts. Anyone managing an enterprise knows that the ability to wake up a remote device is hugely important. You just need to enable it securely... Another tip - make sure the PC's WoL boot sequence is set the way you want it. Some manufacturers set the WoL sequence to PXE boot first, assuming that if you are waking a PC you are doing so to allow it to boot from a PXE server for system builds. This is not the case in our environment (we are waking to patch), so we need to reconfigure some devices to make the boot sequence the same as on a normal boot. Otherwise, the device will loop and look for a PXE server which it will never find...

garank
garank

The first thing I check when setting up a new machine is the WOL setting in the BIOS. The last thing I want to do is walk across campus to turn on a computer. There is a far better utility available to send WOL packets. I use http://www.aquilatech.com/Software/wakeonlan Why would turning on a computer be a security issue anyway? If you are worried about outsiders turning on your workstations then block the port used by magic packet at the router.

chrisbedford
chrisbedford

Your network should already be secure; chances are your server(s) is/are powered on 24x7 so disabling WoL on PCs is hardly a security measure. If an intruder is in a position to remote boot a PC he already has access to your servers! I find WoL an invaluable aid to doing after-hours support. Often it's difficult to get access to users' computers during their working day, and then the silly ditzes turn the machines off when they go home, leaving me no way to sort out whatever it was they wanted fixing. Magic packet to the rescue - saved me (ok, the customer) a fortune in travelling costs already.

juliette.fister
juliette.fister

Now that PCs are being powered off to save energy, we have to use WoL to get our work done, such as patching and software distribution.

SgtPappy
SgtPappy

That seems reasonable. However I can't think of a single Network Admin ever leaving a port like that open on the firewall intentionally. I know if I have to login into my network from outside to turn a computer on, I connect to the internal network using a vpn then issue the WoL packet to the computer in question. I suppose the security issue arises when a haxor pwns a box on the internal network and is able to wake up other computers. But then again if a haxor pwns a box on the internal network we have bigger issues to worry about.