Cisco Certified Network Professional Practice Test 2025 – Your All-in-One Guide to Exam Success!

To configure Root Guard on a port, the command 'spanning-tree guard root' is used in Cisco networking devices. This command is integral to spanning tree protocol operations, as Root Guard allows a port to prevent a non-root bridge from becoming the root bridge. Once Root Guard is enabled on a port, if it detects a bridge with a higher bridge ID (meaning it's not the designated root), the port will be put into a discard state. This helps ensure that the correct root bridge remains in control of the network topology, enhancing stability and preventing undesirable changes in the network's switching environment.

The other options, while related to port configuration and security, do not accurately represent the command necessary to implement Root Guard. They may pertain to different aspects of network management but do not directly configure Root Guard. Understanding the specific command required is essential for effective network configurations and ensuring proper operation of the spanning tree protocol.