允许ssh传入/传出并阻止除特定端口之外的所有传出

Question

我正在尝试创建iptable规则,允许传入和传出ssh连接,然后允许到特定端口的出站连接,然后最终删除任何不匹配的东西.

这些是我提出的规则,SSH规则有效,但当我进入框中时,我似乎无法访问http(端口80),即使我允许它.谁能发现错误？

#!/bin/bash
#clear iptables
iptables -F
iptables -X

#set default policy to drop
iptables -P INPUT DROP
iptables -P OUTPUT DROP
iptables -P FORWARD DROP

#accept everything no matter port on localhost
iptables -A INPUT -i lo -j ACCEPT

#allow established connections
iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
iptables -A OUTPUT -m state --state ESTABLISHED,RELATED -j ACCEPT

#allow input on port 22, (established connections auto accepted)
iptables -A INPUT -p tcp --dport 22 -j ACCEPT

#allow traffic going to specific outbound ports
iptables -A OUTPUT -p tcp --dport 80 -j ACCEPT
iptables -A OUTPUT -p tcp --dport 443 -j ACCEPT
iptables -A OUTPUT -p tcp --dport 6667 -j ACCEPT
iptables -A OUTPUT -p tcp --dport 6697 -j ACCEPT
#...

#drop anything that doesnt match the rules above
iptables -A INPUT -j DROP
iptables -A OUTPUT -j DROP

谢谢你的时间.

Answer 1

您可能想要添加DNS端口,否则您可能无法解析任何主机名.

允许OUTPUT用于TCP和UDP端口53应该有所帮助.