iptablesの設定
sudo systemctl stop firewalld
sudo systemctl disable firewalld
sudo systemctl status firewalld
sudo iptables -nL
sudo yum -y install iptables-services
sudo iptables -F
sudo iptables -nL
sudo /usr/libexec/iptables/iptables.init save
sudo systemctl start iptables.service
sudo systemctl enable iptables.service
sudo reboot
参考
https://qiita.com/miosee/items/0599baa3a01301265a43
https://qiita.com/takc923/items/782bf58b3dd8b7b452a3
https://qiita.com/fbs884/items/492f7596553b7f384236