How to Monitor Network Traffic with vnStat on Ubuntu 20.04

vnStat is available from the official Ubuntu 20.04 repositories. At the time of writing this tutorial, it contains the latest version. Let's first update the list of repositories and then install:

You can verify the installation was successful and find out the version using the command:

Output:

Let's check that the service is running and is already analyzing traffic:

Output:

If you see enabled and active (running), then everything is working.

Right after installation, you need to wait a while for the statistics to accumulate.
To view data for all time and for all network interfaces, run vnstat without parameters:

To view statistics for every 5 minutes:

For every hour:

And this is how the bandwidth usage diagram will be built:

Statistics for days, months or years, respectively:

Here's how you can see the top 10 days by overall channel usage:

View summary statistics for 5 seconds in real time:

And so the utility will show what is happening at the current moment:

If you have several network interfaces, you can select one of them by specifying its name as a parameter in the command:

To disable monitoring of a specific interface and remove all statistics for it, use:

To add it back after that:

To apply the settings after adding, you need to restart vnstat:

As you can see, vnStat is an easy-to-use yet useful tool for analyzing the use of network interfaces.