在centos7上，停用和卸载firewalld,然后启用iptables

 centos7上的firewalld完全是个鸡肋。我们可以停用和卸载firewalld,然后启用iptables：

systemctl stop firewalld
systemctl disable firewalld
yum erase firewalld -y

systemctl enable iptables
systemctl start iptables