Which port security violation mode allows from valid MAC addresses to pass but blocks traffic from invalid MAC addresses?

In 'restrict' mode, the port drops packets from unauthorized MAC addresses and also sends a syslog message, increments a violation counter, and sends an SNMP trap, which is more aggressive than simply blocking.

In 'shutdown' mode, the port immediately err-disables and turns off the port when a security violation occurs, effectively blocking all traffic until manually re-enabled.

In 'protect' mode, a port configured with port security will drop packets from source MAC addresses that are not among the allowed secure MAC addresses, but it will not send notifications or shut down the port.

'Shutdown VLAN' is not a standard port security violation mode; port security violations typically affect the specific port itself.