I'm curious to see what information I'm blasting out to the various services I depend on for internet (ISP, DNS, probably Cloudflare, etc.).
Are there any easy to setup, entirely self-hosted tools I can run on my home network that would allow me to snoop on my own traffic.
I want more than just DNS, so I'm not just looking for pihole and its ilk. I want to see things like SNI and any non-protected traffic that any of the devices on my network might be sending that I just don't know about.
Ideally, it would be something I could leave on without affecting my speed/latency, but something to turn on occasionally and spot check would be better than nothing.
My router runs VyOS, so I should have quite a bit of flexibility in what I do with my traffic, though I never have figured out if/how to deploy custom software to it…
I've used Wireshark when I want to inspect the traffic going through my computer. I've found it particularly handy for debugging my own networking code. I've also used netstat to see active connections and programs listening for traffic when I don't care about the packet contents specifically.