firewall-cmd --add-masquerade --permanent
sudo firewall-cmd --reload

firewall-cmd --add-port=port-number/port-type

1. Make the new settings persistent:

   $ sudo firewall-cmd --runtime-to-permanent

Reference: https://linuxhint.com/centos7_router/

https://docs.fedoraproject.org/en-US/quick-docs/firewalld/