Switch Port Security Configuration

Switch>

Switch>enable

Switch#conf t

Switch(config)#interface fastEthernet 0/1

Switch(config-if)#switchport mode access

 //Need to configure switch port as access port. By default switch port in dynamic port. So you can’t configure port security. It will show “Command rejected: FastEthernet0/1 is a dynamic port.”

Switch(config-if)#switchport port-security

//After configure port as access port. Configure Enable port security by above command.

Switch(config-if)#switchport port-security mac-address 0001.423C.CAD5

//statically configures Allowed MAC address for switchport. Only this port allow on this port.

Switch(config-if)#switchport port-security maximum 2

// If you want to all more device, you can specify the number.

Switch(config-if)#switchport port-security mac-address sticky

//Allow Switch to dynamically learn second MAC address with above command.

Now See Switch Learn MAC address Dynamically:

Switch#show port address

                                    Secure Mac Address Table

-------------------------------------------------------------------------------

Vlan    Mac Address   Type                            Ports                Remaining Age

                                                                                                (mins)

----       -----------          ----                               -----                  -------------

1          0001.423C.CAD5       SecureConfigured       FastEthernet0/1                       -

1          0060.3E4B.3453         SecureSticky               FastEthernet0/1                       -

------------------------------------------------------------------------------

Total Addresses in System (excluding one mac per port)     : 1

Max Addresses limit in System (excluding one mac per port) : 1024

Switch(config-if)#switchport port-security violation shutdown

//Port will be shutdown after third Device/MAC come.

Now see the port status by below command:

Switch#show port-security interface fastEthernet 0/1

Port Security              : Enabled

Port Status                : Secure-up

Violation Mode             : Shutdown

Aging Time                 : 0 mins

Aging Type                 : Absolute

SecureStatic Address Aging : Disabled

Maximum MAC Addresses      : 2

Total MAC Addresses        : 2

Configured MAC Addresses   : 1

Sticky MAC Addresses       : 1

Last Source Address:Vlan   : 0060.3E4B.3453:1

Security Violation Count   : 0

Now See the Port on Shutdown for connect third Device/MAC:
Switch#show port-security
Secure Port MaxSecureAddr CurrentAddr SecurityViolation Security Action
               (Count)       (Count)        (Count)
--------------------------------------------------------------------
        Fa0/1        2          2                 1         Shutdown
----------------------------------------------------------------------
Switch#