One simple security step

[kc1di]

Kubuntu comes with a firewall pre installed but it is sort of hidden and most users may not realize that it's even there.
UFW is it's name and can be enabled by typing this command sudo ufw enable
or you can install gufw in muon for a graphical control like ubuntu has.
in any event it's good practice to enable the firewall after a new install.

[chimak111]

KDE Connect needs (or needed?) some ports open: https://askubuntu.com/questions/9369...g-ports-in-ufw

[claydoh]

Plus, what are routers for?

Well, when one is at home at least.

if Ubuntu enabled the firewall by default, networking and connection problems would jump by about 65438%, I imagine

[kc1di]

I'm not saying it should be enabled by default, just enable after install at some point. It's a good firewall and needs no real interaction by the op. except to enable it.
Ubuntu provides a gui to do that in the control center. Kubuntu does not. but it's simple to install. with the gui UFW can be turned on and off when needed.

you can find more about how to configure UFW for specific cases here: https://wiki.ubuntu.com/UncomplicatedFirewall