CCNA Port Security 2: Sticky Secure MAC Learning

Bundle lab · $29.99

Two access-layer switches have a VLAN 20 connectivity problem: users in one wiring closet cannot reach users in the other. Diagnose and repair the issue, then deploy sticky secure MAC learning on the host-facing access ports so each port dynamically learns and persists its connected host's MAC. Verify sticky entries in show commands and confirm same-VLAN host connectivity end-to-end.

Learning objectives

• Identify and fix a trunk allow-list drift that prevents a user VLAN from traversing between switches
• Configure port security on host-facing access ports so each one automatically learns and locks onto its connected device’s MAC address (sticky learning)
• Set a secure address maximum per port and verify sticky learning in show port-security and running-config
• Validate same-VLAN host connectivity across an 802.1Q trunk

Troubleshooting focus

• Diagnose and resolve the introduced fault: Trunk allow-lists, native VLAN alignment, and host VLAN assignment.
• Verify every link's interface status and IP addressing (`show ip interface brief`) and correct any interface that is down or misaddressed.
• Confirm each device's running configuration matches the lab objective, and bring any interface, route, or service that is not in its expected state back to health.
• Trace end-to-end reachability with ping/traceroute and isolate the first hop where forwarding fails.