For more than 10 years, Arnout Engelen [1] has worked on his Nethogs [2] tool. Nethogs is a little-known utility that breaks down network bandwidth by process. A view of the network by process is particularly useful if you want to know which application is currently involved in a particularly intensive communication.

Nethogs, which is licensed under the GPL, relies on the virtual proc filesystem for the analysis (relying on /proc/net/tcp and /proc/net/tcp6, among others). The code is written in C++. You will find the official source code at the project website [3]. Currently, Nethogs only shows you the TCP data flow; other protocols, such as ICMP or UDP, are not supported. Also, Nethogs analyzes the network usage for a single system and doesn't attempt to study all the traffic on the network.

Easily Installed

Nethogs has found its way by now into the official package repositories for more popular distributions. On the Ubuntu 14.04 64-bit version in our lab, I was able to install the package with the following commands:

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