Switch port protected is used to prevent the communication between two or more ports which are configured as switch-port protected. But an protected port can communicate with an unprotected port and vice versa.
Protected port to protected port – communication is not allowed
Protected port to unprotected port – communication is allowed
Unprotected port to protected port – communication is allowed
Switch(config)#interface Ethernet 0/1 Switch(config-if)#switchport protected Switch(config-if)#exit Switch(config)#interface Ethernet 0/2 Switch(config-if)#switchport protected
Above is the configuration of switch port protected and we are assuming that basic port configuration has been done. if you also want the basic port configuration. then assume all ports are access ports and assigned into VLAN 100. for this requirement we can configure below commands on all three ports:
Switch#conf t Switch(config)#vlan 100 Switch(config)#interface range Ethernet 0/0 - 2 Switch(Config-if)#switchport mode access Switch(Config-if)#switchport access vlan 100
Switch#show interface Ethernet 0/1 switchport Switch#show interface Ethernet 0/1 switchport | in protected
In above example, PC-A is connected on Ethernet 0/1. PC-B is connected on Ethernet 0/2 . Server is connected on Ethernet 0/0.
Port Ethernet 0/1 and Ethernet 0/2 , both are configured as switch port protected.
In this case , PC-A can’t communicate to PC-B and vice versa. But both PCs ( PC-1 and PC-B ) can communicate with server. Because of Server port is not configured as switch port protected.
We can also use Switch port protected as an alternate for private VLAN and port ACLs. Because switch port protected is more easy then private VLAN and port ACLs. Private VLAN also not supported on all Cisco switches. But switch port protected is supported on most of Cisco switches.
I Hope , Now you have understand the switch port protected. if you are still having any doubt then please leave a comment in comment section. I will reply on your all queries.
I Will suggest , you to read below post: