darkstat software package provides network traffic analyzer, you can install in your Debian 9 (Stretch) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install darkstat
darkstat is installed in your system.
Make ensure the darkstat package were installed using the commands given below,
$ sudo dpkg-query -l | grep darkstat *
You will get with darkstat package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Network |
| Package | darkstat |
| Version | 3.0.719-1 |
| Description | network traffic analyzer |
| Sub Section | Net |