Port Security: Err-Disable Auto Recovery

Bundle lab · $29.99

Configure port security in shutdown mode on host-facing access ports and enable automatic errdisable recovery for psecure-violation. The lab uses two Layer-2 switches connected by a trunk and three Linux hosts in the same VLAN to validate baseline L2 connectivity. You will deploy and verify the global errdisable recovery timer and cause while keeping the trunk healthy. Focus is on deterministic configuration and verification via show commands rather than attempting to trigger live violations.

Learning objectives

• Enforce port security on host-facing access ports, using the strictest response so a violation shuts the port down
• Enable automatic errdisable recovery for psecure-violation and set the recovery interval
• Verify port-security state per-interface and global errdisable recovery status
• Validate same-VLAN host reachability across an 802.1Q trunk

Troubleshooting focus

• Access ports accidentally configured as trunks or missing access VLAN
• Port-security commands applied to the trunk (should never be applied to uplinks)
• Errdisable recovery not activated for psecure-violation or interval set too high/low
• Forgetting to cap the number of allowed MAC addresses on the port, resulting in unexpected default behavior