What three actions will the switch take when a frame with an unknown source MAC address arrives at the interface?

Refer to the exhibit.

What three actions will the switch take when a frame with an unknown source MAC address arrives at the interface? (Select three.)
A . Send an SNMP trap.
B . Send a syslog message.
C . Increment the Security Violation counter.
D . Forward the traffic.
E . Write the MAC address to the startup-config.
F . Shut down the port.

View Answer

Answer: A, B, C

Explanation:

Switchport Security Concepts and Configuration

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Switchport Security Violations

The second piece of switchport port-security that must be understood is a security violation including what it is what causes it and what the different violation modes that exist. A switchport violation occurs in one of two situations:

When the maximum number of secure MAC addresses has been reached (by default, the maximum number of secure MAC addresses per switchport is limited to 1)

An address learned or configured on one secure interface is seen on another secure interface in the same VLAN

The action that the device takes when one of these violations occurs can be configured:

Protect―This mode permits traffic from known MAC addresses to continue to be forwarded while dropping traffic from unknown MAC addresses when over the allowed MAC address limit. When configured with this mode, no notification action is taken when traffic is dropped.

Restrict―This mode permits traffic from known MAC addresses to continue to be forwarded while dropping traffic from unknown MAC addresses when over the allowed MAC address limit. When configured with this mode, a syslog message is logged, a Simple Network Management Protocol (SNMP) trap is sent, and a violation counter is incremented when traffic is dropped.

Shutdown―This mode is the default violation mode; when in this mode, the switch will automatically force the switchport into an error disabled (err-disable) state when a violation occurs. While in this state, the switchport forwards no traffic. The switchport can be brought out of this error disabled state by issuing the errdisable recovery cause CLI command or by disabling and re-enabling the switchport.

Shutdown VLAN―This mode mimics the behavior of the shutdown mode but limits the error disabled state the specific violating VLAN.