Cisco Switch Port Security..

 Port Security is a very useful feature that can be used to limit access to switch ports. It means you can bind the MAC address and also 

you can limit the mac address which are authorized .

•Maximum quantity of learned, dynamic MAC addresses can be limited.
•Static, authorized MAC addresses can be pre-configured

Port-Security Violations

If a violation occurs, you have three options with regards to the response:

•Shutdown (default)

•Protect

•Restrict

Protect:- This violent mode silently discard the frame , if the source MAC is the authorized user.

Restrict:- This Violent mode discard the frame but it logs the record .

Switch port-security:- If you only run this command , It means it will learn the first MAC address dynamically and that would be the only MAC is allowed on that port , When second MAC comes it will shutdown the port .

Switch port-security violation restrict:- If you set it to the restrict ,it will discard the frames but it will not make shutdown the port instead it will log the record of violation , means how many times there is a violation on the port .

Switch port-security maximum 3 :-if you set the maximum with a value 3, it means you are going to allowed maximum 3 mac address on the port .Statically or dynamically .

 

                        

Switch port-security mac-address sticky:-It will learn the mac address dynamically and then it will show un in running configuration , and if we save it using write memory then those MAC address will be authorized  as long as there is an entry .

 

Configurations.

interface fa0/1
switchport mode access
switchport access vlan 101
switchport port-security 
switchport port-security violation restrict
switchport port-security mac-address 0022.6732.8d32 vlan access

Verifications.

Switch#show port-security
Switch#show port-security interface fa0/1
Switch#show port-security address