centOS 6.x关闭防火墙步骤
关闭命令：service iptables stop
永久关闭防火墙：chkconfig iptables off
两个命令同时运行，运行完成后查看防火墙关闭状态
service iptables status
centOS 7.x关闭防火墙步骤
关闭命令：systemctl stop firewalld.service
禁止防火墙服务器：systemctl disable firewalld.service
systemctl status firewalld.service查看防火墙状态