Port Security: Voice + Data on One Access Port
Harden a real desk port that carries both data (PC) and voice (IP phone) using switchport voice vlan and access vlan on a single access port. Apply port security with a maximum that accounts for two MAC addresses (phone + PC) so a third device is restricted. A deliberate trunk allow-list drift on the inter-switch link initially blocks the Voice VLAN; learners must repair the trunk and then verify port-security state on the desk port.