iptables 防火墙配置模版

#!/bin/bash
iptables -F
iptables -X
#shell执行
iptables -P INPUT DROP
iptables -P OUTPUT DROP
iptables -P FORWARD DROP
#开启SSH 22端口
iptables -A INPUT -p tcp –dport 22 -j ACCEPT
iptables -A OUTPUT -p tcp –sport 22 -j ACCEPT
#ngnix服务器默认端口，网站可访问
iptables -A INPUT -p tcp –dport 80 -j ACCEPT
iptables -A OUTPUT -p tcp –sport 80 -j ACCEPT
#允许ping
iptables -A INPUT -p icmp -j ACCEPT
iptables -A OUTPUT -p icmp -j ACCEPT
#允许loopback，不然会导致DNS无法正常关闭等问题
iptables -A INPUT -i lo -p all -j ACCEPT
iptables -A OUTPUT -o lo -p all -j ACCEPT
#丢弃坏的TCP包
iptables -A FORWARD -p TCP ! –syn -m state –state NEW -j DROP
#处理IP碎片数量,防止攻击,允许每秒100个
iptables -A FORWARD -f -m limit –limit 100/s –limit-burst 100 -j ACCEPT
#设置ICMP包过滤,允许每秒1个包,限制触发条件是10个包
iptables -A FORWARD -p icmp -m limit –limit 1/s –limit-burst 10 -j ACCEPT
#开启对指定网站的访问
iptables -A INPUT -m state –state ESTABLISHED,RELATED -j ACCEPT
iptables -A OUTPUT -m state –state NEW,ESTABLISHED,RELATED -p tcp -d www.github.com -j ACCEPT

/etc/rc.d/init.d/iptables save
service iptables restart