The purpose of a network monitoring tool is to provide real-time visibility into a network's performance, health, and security. These tools enable administrators to detect issues such as outages, bottlenecks, or unauthorized access effectively. By continuously tracking traffic patterns and device status, network monitoring tools facilitate proactive maintenance and troubleshooting. They often include alert systems to notify admins of potential problems, allowing for rapid response and minimizing downtime. Overall, they are essential for maintaining optimal network operation and security.