QOTD: Hello Linux users, what do you use to monitor your network traffic?

As you can see in most of my screenshots, I have a widget at the top of my screen that shows the current bandwidth usage:

https://movq.de/v/303e1b1cad/a.jpg

But what does that tell me? What do I do when I see a sudden spike and I don’t know where it’s coming from? 🤔 I don’t have an answer for that. I’d like to have something like a summarized log of the recent network activity of all processes.

Something like tcpdump doesn’t help here, because the traffic is often already finished when I notice it.