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.
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.
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.