How do you prevent unauthorized devices from connecting to a Cisco switch? Learn how port security restricts access by limiting allowed MAC addresses per port—a vital skill for Cisco Certified Field Technician (CCT) exam success.
Table of Contents
Question
A technician needs to prevent unauthorized devices from connecting to a Cisco switch. What feature should be configured?
A. MAC address filtering
B. Port security
C. ACLs
D. Spanning Tree Protocol
E. DHCP Snooping
Answer
B. Port security
Explanation
Port security restricts access by limiting the number of MAC addresses on a port, preventing unauthorized connections.
The feature that should be configured is port security.
Port security allows you to control which devices can connect to a switch port by limiting the number of allowed MAC addresses or specifying exact MAC addresses permitted on each port.
By enabling port security, you can:
- Set a maximum number of MAC addresses that can be learned on a port (default is 1).
- Specify which MAC addresses are allowed (static or sticky).
- Define the action the switch takes if an unauthorized device connects (protect, restrict, or shutdown).
When an unauthorized device attempts to connect, the switch can drop packets, log a violation, or disable the port entirely, depending on the configured violation mode.
This feature is configured in interface configuration mode using commands such as:
switchport mode access
switchport port-security
switchport port-security maximum [number]
switchport port-security violation {protect | restrict | shutdown}
switchport port-security mac-address [address]
Port security is the most effective and widely used method on Cisco switches to prevent unauthorized physical access at the network edge.
Port security restricts access by limiting the number of MAC addresses on a port, effectively preventing unauthorized devices from connecting to the network.
Cisco Certified Field Technician (CCT) certification exam practice question and answer (Q&A) dump with detail explanation and reference available free, helpful to pass the Cisco Certified Field Technician (CCT) exam and earn Cisco Certified Field Technician (CCT) certification.