By default, iftop counts all IP packets that pass through the filter, and the direction of the packet is determined according to the direction the packet is moving across the interface. Using the -F option it is possible to get iftop to show packets enter
iftop is a powerful, console-based utility for real-time network bandwidth monitoring. It listens to network traffic on a specified interface (e.g., eth0, wlan0) and displays a continuously updated table of current bandwidth usage.
In this article we discussed 'iftop' command which is a valuable network analysis tool for administrators, providing real-time bandwidth usage stats and aiding in network troubleshooting.