I am trying to set up KDE Connect between a machine running Linux Mint and my Android-device. It does not show up, and it turns out I don't receive any response if I ping it, and I have the same issue trying to ping the machine from my Android device (from Termux). I've tried two different Android devices, but no luck.
This is not an issue with two other machines I have. Both have KDE Connect setup and I can ping the phone just fine, and I can also ping from the phone. They're all connected to the same VLAN. I can also ping from this machine to the other machines. ufw is disabled.
What could be the issue here?
EDIT: Connection established suddenly after installing and running iptraf.
Related, but just hanging this on here. As the default (as installed) security of distributions has improved, so have the amount of headaches when trying to use tools like this increased. For decades, when I've had issues like this is not been because of a LAN firewall issue, and so now my first thought is never been, "I should check the firewall," when it should.
Sadly, firewall info is almost always locked down so that apps can't even check by themselves and provide helpful hints to users.
Anyway, it's been a hard lesson for me to learn, for some reason. I need to practice my mantra: it's always the firewall.