Essential Linux Network Monitoring Tools: nethogs, nload, cbm, iftop & iPerf

1. nethogs (process‑level)

NetHogs is a simple open‑source terminal utility that groups bandwidth usage by process rather than by protocol or subnet, making it useful for identifying which PID is consuming network resources. It relies on the /proc filesystem and works on most Linux distributions. sudo nethogs You can specify a network interface (e.g., sudo nethogs eth0) and adjust options such as refresh rate ( -d), version ( -V), or trace mode ( -t) as described in its manual page.

2. nload (interface‑level)

nload is an open‑source console application that visualizes incoming and outgoing traffic on a selected network interface in real time. It displays a graph, total transferred data, and minimum/maximum usage statistics, providing a quick overview of bandwidth consumption.

3. cbm (interface‑level)

CBM is a lightweight tool that shows colored network traffic for all active interfaces in a compact format. It is as easy to use as it is to install—simply run the command: cbm The output appears at the bottom of the terminal, allowing you to monitor traffic at a glance.

4. iftop (host‑level)

iftop is a free open‑source command‑line monitor that lists active network connections between hosts, sorted by bandwidth usage. By default it shows the “top” bandwidth consumers, and you can sort or filter the list using various parameters.

5. iPerf (performance testing)

iPerf is a widely used tool for measuring and tuning network performance. It supports client and server modes and can generate standardized throughput, loss, and other metrics in one‑direction or bidirectional tests. Two implementations exist: the original iPerf 2 and the newer, non‑backward‑compatible iperf3.

Note: If you are using iPerf3, replace all occurrences of iperf with iperf3 in the examples.

Running iPerf requires two machines: one as a server and one as a client. On the server, start the listener: iperf -s On the client, connect to the server’s address (IP or hostname): iperf -c server_address Replace server_address with the target’s IP or domain (e.g., ping.online.net). The iPerf3 project provides a public list of test servers for experimentation.