Power over Ethernet (PoE) is a networking technology that carries data and electrical power over the same Ethernet cable. Instead of needing a separate power adapter, a PoE-enabled switch or injector can energize devices such as wireless access points, IP cameras, VoIP phones, and sensors through the network port.
PoE matters in cyber security because many security and building devices depend on it to stay online. If PoE fails, a device may lose power even while the data link still looks healthy, creating an outage that is easy to miss. Defenders should monitor both link status and power delivery, especially on switches with PoE or PoE++ ports. Attackers may also target PoE by disconnecting or overloading power paths to disable endpoints without touching the main network traffic.