10 Must‑Try Linux Network Monitoring Tools

Maintaining control over network usage is essential for administrators to prevent programs from monopolising bandwidth and slowing the system. The article presents ten Linux network‑monitoring tools that operate from the terminal, making them ideal for users who manage servers via SSH without a GUI.

1. iftop

Similar to top but focused on network traffic, iftop provides detailed real‑time information about bandwidth usage and the processes consuming it.

2. vnstat

vnstat is included by default in many Linux distributions and allows real‑time tracking of sent and received traffic over a user‑selected time period.

3. iptraf

iptraf is a console‑based real‑time network monitor that gathers a wide range of information, including TCP flags, detailed ICMP data, TCP/UDP traffic errors, packet and byte counts, and interface activity.

4. Monitorix

Monitorix is a lightweight free application designed to monitor many Linux/Unix system and network resources. It includes an embedded HTTP server that periodically collects data and displays it in charts, tracking average load, memory allocation, disk health, services, network ports, mail statistics (Sendmail, Postfix, Dovecot, etc.), MySQL statistics, and more to help detect faults, bottlenecks, and abnormal activity.

5. dstat

Although less well‑known, dstat is included in some distributions. It provides interactive data collection from network connections and can export the results in various formats for use by other tools.

6. bwm‑ng

bwm‑ng is one of the most simplified tools. It interactively retrieves data from connections and can export it in several formats, making the information easy to consume by other devices.

7. ibmonitor

Similar to bwm‑ng , ibmonitor displays filtered traffic per interface and clearly separates received from transmitted traffic.

8. htop

htop is an advanced, interactive, real‑time Linux process monitor. It offers a more user‑friendly interface than top, with shortcuts, horizontal and vertical process views, and additional features. It is not bundled with the OS and must be installed via a package manager such as yum or apt‑get.

9. arpwatch

arpwatch monitors Ethernet activity, recording IP‑to‑MAC address changes with timestamps. When a new or changed pair is detected, it can email the administrator—useful for detecting ARP attacks.

10. Wireshark

Wireshark (originally named Ethereal) is a free application that captures and inspects packets traveling to and from the system. It allows deep packet analysis, protocol investigation, and testing of special cases. Its lightweight, easy‑to‑understand interface categorises protocol information from multiple real systems, making it the de‑facto standard network analyzer.

In conclusion, the article examined several open‑source network monitoring utilities and labeled them as “best” choices, while acknowledging that they may not suit every situation. It suggests exploring other open‑source options such as OpenNMS, Cacti, and Zennos, as well as proprietary tools, based on individual requirements.