Network analyzers are vital tools for network administrators, as they allow them to monitor and analyze network traffic to identify issues and optimize performance. While there are many paid network analyzers available, there are also several excellent free and open-source options. In this article, we’ll take a look at 16 of the best free and open-source network analyzers that you can use to keep your network running smoothly.

1. Wireshark
Wireshark is perhaps the most well-known network analyzer on this list. It is a powerful tool that can capture and analyze network packets in real-time. Wireshark supports multiple protocols and is available for Windows, macOS, and Linux.

2. Nmap
Nmap is a versatile network scanning tool that can be used for network discovery, security scanning, and auditing. It supports multiple scanning techniques and is available for Windows, macOS, and Linux.

3. tcpdump
Tcpdump is a command-line network analyzer that can capture and display network packets on the fly. It is available for Unix-like operating systems and is a great tool for network troubleshooting.

4. EtherApe
EtherApe is a graphical network monitor that displays network activity in real-time using a visual representation of the network. It is available for Linux and is a good tool for visualizing network traffic.

5. Netcat
Netcat is a versatile networking tool that can be used for various purposes, including port scanning, file transfer, and network debugging. It is available for Windows, macOS, and Linux.

6. Capsa Free
Capsa Free is a network analyzer that provides real-time monitoring and analysis of network traffic. It supports various protocols and is available for Windows.

7. SolarWinds Network Performance Monitor
SolarWinds Network Performance Monitor is a comprehensive network monitoring tool that provides in-depth visibility into network performance and health. It is available for Windows.

8. OpenNMS
OpenNMS is an enterprise-grade network monitoring and management platform that provides real-time monitoring, alerting, and reporting. It is available for Windows, macOS, and Linux.

9. Nagios Core
Nagios Core is a popular open-source network monitoring tool that provides monitoring and alerting for network devices and services. It is available for Windows, macOS, and Linux.

10. Zenoss Core
Zenoss Core is an open-source network monitoring tool that provides real-time monitoring, alerting, and reporting for network devices and services. It is available for Windows, macOS, and Linux.

11. Icinga
Icinga is an open-source network monitoring tool that provides monitoring, alerting, and reporting for network devices and services. It is available for Windows, macOS, and Linux.

12. PRTG Network Monitor
PRTG Network Monitor is a comprehensive network monitoring tool that provides real-time monitoring, alerting, and reporting for network devices and services. It is available for Windows.

13. ManageEngine OpManager
ManageEngine OpManager is a network monitoring and management tool that provides real-time monitoring, alerting, and reporting for network devices and services. It is available for Windows.

14. Zabbix
Zabbix is an open-source network monitoring tool that provides monitoring, alerting, and reporting for network devices and services. It is available for Windows, macOS, and Linux.

15. Observium
Observium is a network monitoring and management tool that provides real-time monitoring, alerting, and reporting for network devices and services. It is available for Windows, macOS, and Linux.

16. Pandora FMS
Pandora FMS is a comprehensive network monitoring and management tool that provides real-time monitoring, alerting, and reporting for network devices and services. It is available for Windows, macOS, and Linux.

In conclusion, there are many excellent free and open-source network analyzers available that can help you monitor and optimize your network performance. Whether you need a tool for real-time monitoring, alerting, or reporting, there is likely a network analyzer on this list that meets your needs. Consider trying out a few of these tools to see which one works best for your network environment.