Configuring Protected Ports on Cisco

On the test, I will configure the Cisco Catalyst WS-C3750-48TS-S.

And so, all ports are configured as access, except for the first Gigabit uplink port, it is configured as a trunk and the Internet on the client vlan with the tag comes to it.
We need all the ports on this switch to not see each other and see only the first gigabit ulink port.

To do this, connect to the switch and go into the configuration mode:

enable
configure terminal

Then, we issue the switchport protected command for all access ports:

interface range fastEthernet 1/0/1-48
switchport protected
interface range gigabitEthernet 1/0/2-4
switchport protected
exit
exit

Save the configuration:

write

Apparently interface gigabitEthernet 1/0/1 we did not touch.
Now the ports on which the switchport protected command is registered do not see the other ports on which this command is also registered, they see only the ports where it is not registered, that is, in our case the first gigabit ulink port, and it sees all the ports with the command and without.

Information about ports can be viewed by the command:

show interfaces NAME switchport

View full configuration:

show running-config

See also:
Port isolation on Huawei switches
Port isolation on the ZyXEL MES-3528 switch

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