How to set up KDE connect?

Question

linux

Welcome all.
I have Linux with KDE Connect, an Android 7 tablet, and a keenetic lite 3 router. I need to transfer files from PC to tablet via Wi-Fi. Communication between a PC and a tablet is organized through a router. The problem is that when running KDE connect on a PC, it doesn't see the tablet, and KDE connect on the tablet doesn't see the PC. On the tablet, I entered the ip-address of the computer into the program, and in Linux I executed the commands.

sudo firewall-cmd --zone=public --add-port=1714-1764/tcp
sudo firewall-cmd --zone=public --add-port=1714-1764/udp
sudo systemctl restart firewalld.service

But it doesn't help. Maybe it's the router. I tried to set up address translation (without any understanding of what to translate where), set different rules, but it doesn’t help either.
How to diagnose and fix the problem?

Answer 1

I was able to start KDE Connect and upload a few files. The problem was not in the router and not in zone=public - this zone is set by default in firewalld:
The problem was that the commands I gave above didn't work properly. I copied them from official sources, but I dropped the --permanent option, which is used to ensure that the established rules work even after a firewall restart. Since the last command restarted firewalld, the previous rules were simply not saved and the firewall-cmd --list-ports command did not produce anything.
In the end, I added these ports through the GUI, but I also added the kdeconnect service to the list of allowed ones in the same place. Although, perhaps, it was enough to perform one action. In any case, the service has earned.