What should be added to an access list protecting a management interface connecting to an out-of-band management network?

Adding an explicit permit for specific management workstations to an access list protecting a management interface connected to an out-of-band management network is crucial for security and functional effectiveness. By permitting only designated management workstations, you restrict access to the management interface, ensuring that only authorized personnel or devices can interact with the system.

This approach minimizes the potential attack surface by preventing unauthorized access attempts from unintended sources. It is a fundamental security practice to limit network access strictly to necessary entities, thereby mitigating risks of unauthorized configuration changes or exposure to network vulnerabilities.

While other options, such as permitting all other IP traffic or denying it, could be considered in specific contexts, they do not provide the focused control needed for a management interface. Allowing all traffic can open vulnerabilities, while a blanket denial would inhibit all communication, including legitimate access from management workstations. Hence, permitting specific management workstations is the most effective strategy for maintaining a secure and functional network management environment.