Open Source Network Monitors

Foremost network protocol analyzer with multi-platform support, deep protocol inspection, VoIP analysis, and extensive file format compatibility.

Free and open-source tool that monitors all network activity, blocks unwanted connections, uses filter lists for ads and malware, enforces DNS-over-TLS, and sets custom app rules.

Free, open-source utility for network security auditing and exploration with capabilities for OS detection, service identification, and large network scans.

A free, powerful, multi-purpose tool that helps you monitor system resources, debug software and detect malware. Official successor to Process Hacker.

TrafficMonitor is a network monitoring suspension window software in Windows. It can display the current network speed, CPU and memory usage. It also support the functions of display in the taskbar, change skin and historical traffic statistics.

Gather and analyze accurate statistics and performance metrics, visualize it, get notified about current and potential issues without delay, and take advantage of our time-tested professional development and support.

Resource monitor that shows usage and stats for processor, memory, disks, network and processes.

Monitor your CPU, Memory, Disk, Network and GPU usage.

Zenmap is the official cross-platform GUI for the Nmap Security Scanner. It is free and runs on Linux, Windows, Mac OS X, etc. Zenmap aims to make Nmap easy for beginners to use while providing advanced features for experienced Nmap users.

Advanced self-hosted tool for tracking uptime across multiple services with reactive UX, interval checks, various notifications, and multi-language support.

Sniffnet is a network monitoring tool to help you easily keep track of your Internet traffic.

Glances is a cross-platform monitoring tool which aims to present a large amount of monitoring information through a curses or Web based interface. The information dynamically adapts depending on the size of the user interface.

Nagios is a powerful monitoring system licensed under Nagios Enterprises that helps organizations identify and resolve IT infrastructure issues.

Beszel is a lightweight server monitoring platform that includes Docker statistics, historical data, and alert functions.

Prometheus is an open-source systems monitoring and alerting toolkit originally built at SoundCloud. Since its inception in 2012, many companies and organizations have adopted Prometheus, and the project has a very active developer and user community.

Censys is a search engine that allows computer scientists to ask questions about the devices and networks that compose the internet.

A lightweight, highly customizable system tray application that monitors and displays real-time network speeds for Windows.

Monitorix is a system monitoring tool designed to monitor as many services and system resources as possible. Due to its simplicity and small size it can also be used on embedded devices.

LibreNMS is an autodiscovering PHP/MySQL based network monitoring system forked from Observium. LibreNMS aims to be easy to use, painless to deploy, and support monitoring of a wide range of devices. Observium's license changed to a modified QPL license in May 2012, and...

Lightweight, performant interactive network connection monitor with friendly service names.

Resource monitor that shows usage and stats for processor, memory, disks, network and processes.

Python port of bashtop.

“Data Monitor" is a user-friendly, free and open source app for you to manage your data usage. “Data Monitor" helps you to accurately measure your daily data traffic, and analyze the data in a way easy to understand.

NETworkManager is a powerful tool for managing networks and troubleshoot network problems! It includes a variety of tools such as an IP scanner, Port Scanner, Ping Monitor, WiFi analyzer, PuTTY/RemoteDesktop with tabs or an LLDP/CDP capture (and many more) in a unified user...

SmokePing is a deluxe latency measurement tool. It can measure, store and display latency, latency distribution and packet loss. SmokePing uses RRDtool to maintain a longterm data-store and to draw pretty graphs, giving up to the minute information on the state of each network...

BitMeter OS keeps track of how much you use your internet/network connection, and allows you to view this information in a variety of ways.