[root@localhost ~]# yum install iptables -y
[root@localhost ~]# yum install iptables-services
查看安装情况
[root@localhost ~]# rpm -qa|grep iptables
iptables-1.4.21-24.1.el7_5.x86_64
iptables-services-1.4.21-24.1.el7_5.x86_64
修改配置文件
[root@localhost ~]# vi /etc/sysconfig/iptables
#firewall configuration written by system-config-firewall # Manual customization of this file is not recommended. *filter :INPUT ACCEPT [0:0] :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [0:0] -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT -A INPUT -p icmp -j ACCEPT -A INPUT -i lo -j ACCEPT -A INPUT -m state --state NEW -m tcp -p tcp --dport 22 -j ACCEPT -A INPUT -m state --state NEW -m tcp -p tcp --dport 80 -j ACCEPT -A INPUT -m state --state NEW -m tcp -p tcp --dport 3306 -j ACCEPT -A INPUT -j REJECT --reject-with icmp-host-prohibited -A FORWARD -j REJECT --reject-with icmp-host-prohibited COMMIT 保存退出
[root@localhost ~]#systemctl start iptables.service
启动正常，安装成功。
[root@localhost ~]# systemctl enable iptables
[root@localhost ~]# iptables -nv -L --line-number //查看IP规则 ,--line-number 标上序号