{ 1. 查看防火墙iptables当前运行状态 }

service iptables status

//未启动
iptables: Firewall is not running. 

//已启动
Table: filter
Chain INPUT (policy ACCEPT)
num  target     prot opt source               destination
...

Chain FORWARD (policy ACCEPT)
num  target     prot opt source               destination
...

Chain OUTPUT (policy ACCEPT)
num  target     prot opt source               destination
...

{ 2. 操作/控制防火墙 }

//启动
service iptables start

//关闭
service iptables stop

//重启
service iptables restart

{ 3.查看当前防火墙配置信息 }

iptables -L -n

Table: filter
Chain INPUT (policy ACCEPT)
num  target     prot opt source               destination
...

Chain FORWARD (policy ACCEPT)
num  target     prot opt source               destination
...

Chain OUTPUT (policy ACCEPT)
num  target     prot opt source               destination
...