wOl

Wake-on-LAN (WOL) is a computer networking standard that allows a computer to be powered on or awakened from a low power state remotely. The device is awakened by a magic packet—a specially formatted frame sent over the local area network that contains the target machine's Media Access Control (MAC) address repeated several times. The most common form places six 0xFF bytes followed by sixteen repetitions of the MAC address in the payload. The network interface card (NIC) must support WOL, and the computer's BIOS/UEFI settings must enable WOL, as must the OS power management settings. In addition, the system must have at least some power supplied to the NIC, generally provided by standby power.

WOL is typically used on wired Ethernet networks; wake over wireless connections (WoWLAN) exists but is less common and hardware- and driver-dependent. Reaching a device across subnets requires additional configuration, such as forwarding magic packets to the broadcast address or using a VPN to the local network.

Common use cases include remote administration, maintenance, and energy management in data centers or enterprise environments. Security considerations include the potential for unauthorized wakeups; administrators often disable WOL when not needed and may restrict wake packets to trusted networks, implement VLANs, or require VPN access.

Historically, WOL became a standard feature in network interface hardware in the 1990s and remains widely supported by modern desktops, laptops, and servers.