what is a magic packet for wake on lan
Ethernet connections, including home and work networks, wireless data networks and the Internet itself, are based on frames sent between computers. Wake-on-LAN ("WOL") is implemented using a specially designed frame called a magic packet, which is sent to all computers in a network, among them the computer to be awakened. The magic packet contains the MAC address of the destination computer, an identifying number built into each network interface card ("NIC") or other ethernet device in a computer, that enables it to be uniquely recognized and addressed on a network. Powered-down or turned off computers capable of Wake-on-LAN will contain network devices able to "listen" to incoming packets in low-power mode while the system is powered down. If a magic packet is received that is directed to the device's MAC address, the NIC signals the computer's power supply or motherboard to initiate system wake-up, in the same way that pressing the power button would do.