DD centos7 启用IPTABLES

停用firewalld防火墙，删除开机启动firewalld防火墙，卸载firewalld防火墙

systemctl disable firewalld
systemctl stop firewalld
systemctl mask firewalld
systemctl disable firewalld.service

安装并设置开机启动

yum install iptables -y
yum install iptables-services -y
systemctl enable iptables
systemctl enable iptables.service

修改SSH登录端口

vi /etc/ssh/sshd_config