As title, I would like to know what firewall is used by default in friendlycore-lite-focal. Is it ufw, iptables, or nftables? Because I would like to use VNC, but I have been unable to establish a connection.

I want to record videos on Ubuntu using NanoPi R4S, but after searching through various forums, most of the discussions point towards issues with encoders. So, is it feasible to use OBS Studio on Ubuntu with NanoPi R4S for video recording?