1. 查看防火墙入口规则： ~~~ [root@izbp192gcqz9hrnj21lewuz ~]# iptables -L -n Chain INPUT (policy ACCEPT) target prot opt source destination Chain FORWARD (policy ACCEPT) target prot opt source destination Chain OUTPUT (policy ACCEPT) target prot opt source destination ~~~ 2. 增加防火墙入口规则： ~~~ [root@izbp192gcqz9hrnj21lewuz ~]# iptables -A INPUT -p tcp -m state --state NEW -m tcp --dport 3306 -j ACCEPT ~~~ 3. 查看防火墙入口规则： ~~~ [root@izbp192gcqz9hrnj21lewuz ~]# iptables -L -n Chain INPUT (policy ACCEPT) target prot opt source destination ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 state NEW tcp dpt:3306 Chain FORWARD (policy ACCEPT) target prot opt source destination Chain OUTPUT (policy ACCEPT) target prot opt source destination ~~~