CCNA Port Security 1: Enable & Verify on Access Ports

Free preview — the first lab of Switchport Port Security

Hands-on fundamentals with Cisco port security on host-facing access ports. Build a small two-switch campus with a trunk, place two Linux hosts in the same user VLAN, then enable port security with the explicit defaults (maximum 1, violation shutdown) on both host ports. Verify secure-up state and baseline host connectivity.

Learning objectives

• Configure access ports and a basic inter-switch 802.1Q trunk for a user VLAN
• Enable port security on host-facing access ports
• Explicitly configure and verify the feature's default enforcement policy so a port allows exactly one learned MAC address and disables itself on any violation
• Validate host connectivity and interpret show port-security outputs

Troubleshooting focus

• Confirm ports are in access mode with the correct VLAN before enabling port security
• Check that port-security is not applied to the trunk uplink
• Use show port-security and show port-security interface to confirm secure state

Topology