For the last decade (until early 2019), ICSI Netalyzer (which lived at http://netalyzr.icsi.berkeley.edu/) was a wonderful tool for checking and debugging network problems of all descriptions, with checks for a really large number of things, from MTU problems to malicious DNS providers to bufferbloat. It's been my go-to tool any time I've needed to debug weird network issues for quite a while.
Unfortunately, last year, that project was shut down and the website mothballed. Unfortunately, the client (a java app, running in either a browser, or out of a local .jar) needs to talk to the netalyzr server to be able to do its job, so it is now useless, and no source has been released for the client or the server, so the tool is effectively dead at this point.
So, my question is: Does anyone know of a replacement that has a bulk of the functionality that netalyzr had? I've been looking for a few months now, and I've not been able to find anything that even begins to work as a reasonable substitute.
Has anyone had better luck finding a replacement than I have?