Ufw - mac firewall
From Wasya Wiki
sudo ufw status verbose
sudo ufw allow from 127.0.0.1 to 127.0.0.1 port 3306 proto tcp
sudo ufw allow to any port 3306 proto tcp
ubuntu firewall config
From: https://askubuntu.com/questions/1259860/on-ubuntu-20-04-how-do-you-open-a-port-in-the-firewall
sudo ufw enable sudo ufw allow 4200