Port security is a Layer 2 security feature that restricts the number of devices connecting to a network switch port. It helps prevent unauthorized devices, such as an unmanaged switch, from being connected to the network.
How Port Security Works:
Limits the number of MAC addresses that can connect to a port.
Can shut down or restrict the port if an unauthorized device is detected.
Prevents users from plugging in unauthorized networking equipment (e.g., unmanaged switches, hubs).
Incorrect Options:
A: Screened Subnet: A screened subnet (DMZ) is used for isolating external-facing servers, not for controlling unauthorized network connections.
B: 802.1X: Provides authentication for devices but requires a RADIUS server, which is a more complex solution than port security.
C: MAC Filtering: Controls which MAC addresses can connect but is difficult to manage and can be spoofed.
Reference:
CompTIA Network+ N10-009 Official Study Guide - Chapter on Network Security Controls