ntopng

It's remarkable that most home networks provide very little analysis of the network traffic they're carrying, or further details on what they're sending to and receiving from the Internet. The best that most home routers can manage is a network usage graph, perhaps with a pie chart split into broad packet categories for video, file transfers, and music. One of the reasons we don't have access to deeper analytics is likely because the vast majority of users can't even log into their routers, let alone worry about the seven layers of the OSI model or the difference between UDP and TCP. But there should be a middle option for those of us who do want it, and ntopng might be that option. As its name suggests, ntopng is the "next generation" version of the general network analysis tool ntop, which was itself developed to show network status in the same way the top command did for process status.

The big difference between ntop and ntopng is that rather than sending output to the command line, you instead study its packet analysis through a web browser. It latches on to a network interface, or even a Wireshark online or offline packet capture, and sorts the network traffic according to many different criteria. The most useful are local and remote IP addresses, which application protocols are being used, currently active hosts and their "live flows" of interconnectivity, and even geolocation analysis. It can go much deeper, but most average Linux users will be able to derive a lot from these charts alone. The only downside is that ntopng is only an open source core project, which means there are limitations in the downloadable version. This version is called the "community" version, and its limitations won't affect home users wanting to add a missing feature to their router to understand their networks better, but may temper what should otherwise be an overwhelmingly positive recommendation.

Project Website

https://github.com/ntop/ntopng

If you have a FRITZ!Box router, an ntopng script can grab packets from your entire network for further analysis on another machine.

FIT file manager

PostRunner

The idea of the quantified self, where you track and learn from biometric data generated by your activity, first appeared a couple of decades ago. It took time for our technology to catch up, but self-monitoring and analysis is now common and extends far beyond the number of steps you take or the flights of stairs you climb. Google's Fitbit, Apple's Watch, Garmin's trackers, and devices from many other manufacturers can now monitor heart rhythm, blood oxygen levels, cardio fitness, respiration rates, stress, sleep, hydration, activity, temperature, and many other statistics. The downside, of course, is that this data is difficult to access outside of each manufacturer's walled garden, and this is where PostRunner can help – at least for users of some common Garmin devices. PostRunner is a command-line utility that can manage and interpret the FIT files generated by many Garmin devices, including its Forerunner and fØenix fitness watches, and it can do this better than Garmin's native tools.

FIT, Garmin's "Flexible and Interoperable Data Transfer Protocol," includes sensor parameters, session events, and real-time activity tracking. The format is unfortunately not open source, but it is well documented with an open API. FIT-formatted files can be downloaded directly from Garmin's web portal, but they can also be accessed purely offline from a device via its USB-mounted FAT or MTP filesystem. PostRunner has been developed to import these files directly to avoid cloud services or online interpretation. After running the postrunner import command, the target FIT file is decoded and added to PostRunner's internal database. Each activity will get its own reference, starting from 1. Further commands such as summary, monthly, events, and records can be used to view activities and output aggregated data, including internal totals and personal records. Best of all, running postrunner show generates a beautifully rendered web page for each activity, charting parameters such as speed and altitude alongside an OpenStreetMap view of a route and the raw GPS data. It's just as good and less opinionated than the hosted equivalents from the big manufactures, and best of all, your data hasn't gone anywhere.

Project Website

https://github.com/scrapper/postrunner

Alongside displaying FIT activity data, PostRunner can even extract seven days worth of Extended Prediction Orbit data to help make GPS locks much quicker.