Oracle Cloud adding Firewall Exceptions

Maybe you wanna start a new docker container in a port of your VPN, but after you start the container in the port, you can't reach it out, why?, because you should add the firewalld exception to it.

to see a list of open ports in the public zone

sudo firewall-cmd --zone=public --list-all

that command will print

public
  target: default
  icmp-block-inversion: no
  interfaces: 
  sources: 
  services: dhcpv6-client http ssh
  ports:
  protocols: 
  forward: yes
  masquerade: no
  forward-ports: 
  source-ports: 
  icmp-blocks: 
  rich rules: 

Ports are empty, or the port where you have your docker container is not in the list, so, lets add it.

sudo firewall-cmd --permanent --zone=public --add-port=80/tcp 

once done you will see your site available in that port! congratulations!!