On Debian Buster I have installed the UFW Firewall
However, after enabling
$ ufw enable Command may disrupt existing ssh connections. Proceed with operation (y|n)? y Firewall is active and enabled on system startup
The Firewall is disabled after Reboot
$ ufw status Status: inactive
The Config-File looks like this:
nano /etc/ufw/ufw.conf ENABLED=yes
Help is very appreachiated!