Use show port-security interface interface to verify Port Security on a specified Cisco IOS interface, including operational state, MAC limits, learned addresses, violations, and the most recent source address. section 12.1.2 section 12.3
Interpreting interface output
SW1# show port-security interface f0/1 Port Security : Enabled Port Status : Secure-up Violation Mode : Shutdown Maximum MAC Addresses : 1 Total MAC Addresses : 1 Last Source Address:Vlan : 3c57.311a.a480:1 Security Violation Count : 0 This output confirms that Port Security is active, the port is operational, one MAC address is allowed and learned, and no violation has occurred. After a violation, Port Status becomes Secure-shutdown, dynamically learned addresses are cleared, and the violation counter increases.
