Which common threat can be prevented by implementing port security on switch ports?

VLAN hopping attacks exploit misconfigurations in trunking or double-tagging and are prevented by features like disabling DTP or using dedicated VLANs for trunks, not primarily by port security.

Port security prevents spoofing attacks by allowing an administrator to restrict input to an Ethernet port by limiting and/or identifying the MAC addresses of hosts allowed to connect to it. If an unauthorized MAC address attempts to send traffic, the port can be shut down, preventing the attacker from impersonating a legitimate device.

While port security can prevent a single device from overwhelming a port with traffic from multiple spoofed MACs, it's not the primary or most comprehensive defense against general denial-of-service attacks, which often target network services or bandwidth.

Eavesdropping attacks involve passively listening to network traffic and are prevented by encryption; port security doesn't prevent an attacker from listening if they are already connected or have compromised a connected device.