Apps to Network Monitoring

Nmap is a free and open-source utility for network discovery and security auditing. It utilizes raw IP packets to determine what hosts are available on the network, what services (application name and version) those hosts are offering, what operating systems (and OS versions) they are running, what type of packet filters/firewalls are in use, and dozens of other characteristics. It is command-line driven, though official GUI versions are also available.

Process Hacker is a free and open-source system utility that provides in-depth monitoring and manipulation of processes, threads, and kernel objects.

Rainmeter is a free and open-source desktop customization application for Windows. It allows users to display various types of information, such as system metrics, time, weather, and RSS feeds, directly on their desktop through highly customizable 'skins'. It's a popular tool for creating personalized and functional desktop interfaces.

Wireshark is a leading open-source network protocol analyzer that empowers users to inspect and understand network traffic at a granular level. Widely used by network professionals, security experts, and developers for troubleshooting, analysis, software and communications protocol development, and education.

Munin is a free and open-source networked resource monitoring tool designed to help users analyze resource trends and identify performance bottlenecks. It offers a simple yet powerful way to visualize the health of servers, applications, and network devices over time.