Most command line based network tools in Linux only allow you to monitor network activities in real time and do not create a log file for later analysis.
Is there a tool that allows you to create and save a visual diagram (graph format) of incoming and outgoing network traffic and a text based log for later analysis?
Something comparable to the diagrams and data you would find on many routers, just directly in Linux and without having to install a complex server / client model with a database?