====== UFW Firewall ======
  - Install with:<code>apt update
sudo apt install ufw</code>
  - Check preset profiles and allow necessary services as root:<code>sudo ufw app list
sudo ufw default allow outgoing
sudo ufw allow http/tcp
sudo ufw allow https
sudo ufw allow 3493 # NUT
sudo ufw allow <custom port>/tcp # FTP
sudo ufw allow <custom port:range> # FTP passive port range/tcp</code>
  - Enable firewall and check status:<code>ufw enable
sudo ufw status</code>
  - Remove firewall rule:<code>sudo ufw status numbered
sudo ufw delete <rule number></code>