iptables -P INPUT DROP  //关闭所有端口

iptables -A INPUT -p tcp --dport 22 -j ACCEPT
iptables -A OUTPUT -p tcp --sport 22 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -m state --state NEW,ESTABLISHED -j ACCEPT
iptables -A OUTPUT -p tcp --sport 80 -m state --state NEW,ESTABLISHED -j ACCEPT
iptables -A INPUT -s 127.0.0.1 -d 127.0.0.1 -j ACCEPT
iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
iptables -A OUTPUT -j ACCEPT

//打开 vsftp
iptables -A INPUT -p tcp -m multiport --dport 20,21 -m state --state NEW -j ACCEPT
iptables -A INPUT -p tcp -m state --state NEW -m tcp --dport 21 -j ACCEPT
iptables -A INPUT -p tcp --dport 30000:31000 -j ACCEPT