vps在被利用发送垃圾邮件的时候会被服务商判定为spam行为，导致vps被暂停，所以我们需要把邮件端口屏蔽。

此脚本基于debian系统。 

#!/bin/bash
#input rules
iptables -A OUTPUT -p tcp -m multiport --dports 25,26,109,110,143,220,366,465,587,691,993,995,2710,6881 -j REJECT --reject-with tcp-reset
iptables -A OUTPUT -p udp -m multiport --dports 25,26,109,110,143,220,366,465,587,691,993,995,2710,6881 -j DROP
#save
iptables-save > /etc/iptables
touch /etc/network/if-pre-up.d/iptables
chmod +x /etc/network/if-pre-up.d/iptables
echo "#!/bin/sh" >> /etc/network/if-pre-up.d/iptables
echo "/sbin/iptables-restore < /etc/iptables" >> /etc/network/if-pre-up.d/iptables
iptables-save > /etc/iptables
iptables -L

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