vnStat

What vnStat is

vnStat is a console-based network traffic monitor for Linux and self-hosted environments. It records traffic for selected network interfaces using statistics supplied by the kernel, rather than sniffing network traffic. It can watch multiple interfaces at the same time and present summaries across five-minute, hourly, daily, monthly and yearly periods, along with top-days statistics. Data retention can be configured. The documented defaults keep five-minute records for 48 hours, hourly records for four days, daily records for two full months and yearly records indefinitely. Output options include text, JSON and XML database output, alerts, and images when the GD Graphics Library is installed. The maker says the program uses system resources lightly regardless of traffic rate. vnStat is free and open source under GPL, with a listed price of $0. Source is offered for Linux and BSD, and the maker provides links to Docker and Snap distributions. The maker also describes optional GPG verification for the stable release archive and its signature.

Who it suits

vnStat suits Linux or self-hosted users who want interface-level traffic records and historical summaries without traffic sniffing. It can also suit users who need configurable retention, alerts or text and database output.

Limits

Traffic estimates work fairly well when interface traffic stays at a similar magnitude, but cannot predict peaks. The documented default retention periods vary by interval; yearly data is kept indefinitely.

Getting started

1. Visit https://humdi.net/vnstat/.
2. Choose a Linux or BSD source distribution, or follow a Docker or Snap link.
3. Optionally verify the stable release archive and signature with GPG.
4. Configure the interfaces and retention you want to monitor.

Verdict

Choose vnStat if you want free, kernel-statistics-based traffic monitoring with multiple reporting periods and configurable retention. Look elsewhere if you need traffic sniffing or estimates that anticipate peaks.