iog software package provides network I/O grapher, 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 iog
iog is installed in your system.
Make ensure the iog package were installed using the commands given below,
$ sudo dpkg-query -l | grep iog *
You will get with iog package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Network |
| Package | iog |
| Version | 1.03-3.6 |
| Description | network I/O grapher |
| Sub Section | Net |