Chapter 8. What About Power over Ethernet?

An Ethernet switch can provide electrical power to attached stations with the help of Power over Ethernet (PoE). Although PoE seems like a small feature, someone can attack it to either get free power or deny services. To reduce the impact of attacks, you can configure switches.

Introduction to PoE

Before the IEEE standard, Cisco provided a way[1] to power a device through the RJ-45 connector and its associated Category 5 (CAT5) cable. Since 2003, the IEEE 802.3af[2] standard specifies the same feature but in a different way.

The main motivation behind PoE is to simplify the cabling of Ethernet devices. If the device’s power consumption is less than 15.4 Watts (W), the Ethernet switch can provide the electrical ...

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