Which of the following describes a primary action of using Nessus in a network?

Identifying system vulnerabilities is a fundamental action of using Nessus within a network. Nessus is a vulnerability scanner designed to analyze systems, applications, and devices for potential security weaknesses. By conducting comprehensive scans, Nessus can uncover vulnerabilities such as outdated software, misconfigurations, and missing patches, helping organizations understand their security posture. This proactive identification is crucial for mitigating risks and enhancing a network's overall security.

Other forms of network management or monitoring activities, such as monitoring user activity, configuring firewall rules, and managing internet bandwidth, fall outside the primary function of Nessus. These activities typically involve other tools or systems focused on real-time monitoring or policy enforcement, whereas Nessus specializes specifically in vulnerability assessment.