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…
You could do the option of mirroring switchboards and then dumping that traffic to a device running packet analysis tools, but since you mentioned VyOS I would imagine at least some of those tools would be present already. You would just want to look for any packages like wireshark, tshark, or maybe tcpdump. You can write either display or capture filters to isolate out to specific things you're interested in in the moment. That's probably the simplest way.