iptables +后缀无法发送电子邮件

Question

最近，我的主机提供商给我发了一封信，说我的服务器受到了某种攻击。我不喜欢安全性，所以我找到了一些教程，用iptables关闭了所有未使用的端口。

下面是我的iptable列表：

Chain INPUT (policy DROP)
target     prot opt source               destination         
DROP       tcp  --  anywhere             anywhere            tcp flags:FIN,SYN,RST,PSH,ACK,URG/NONE 
DROP       tcp  --  anywhere             anywhere            tcp flags:!FIN,SYN,RST,ACK/SYN state NEW 
DROP       tcp  --  anywhere             anywhere            tcp flags:FIN,SYN,RST,PSH,ACK,URG/FIN,SYN,RST,PSH,ACK,URG 
ACCEPT     all  --  anywhere             anywhere            
ACCEPT     all  --  anywhere             anywhere            state RELATED,ESTABLISHED 
ACCEPT     tcp  --  anywhere             anywhere            tcp dpt:www 
ACCEPT     tcp  --  anywhere             anywhere            tcp dpt:https 
ACCEPT     tcp  --  anywhere             anywhere            tcp dpt:smtp 
ACCEPT     tcp  --  anywhere             anywhere            tcp dpt:ssmtp 
ACCEPT     tcp  --  anywhere             anywhere            tcp dpt:pop3 
ACCEPT     tcp  --  anywhere             anywhere            tcp dpt:pop3s 
ACCEPT     tcp  --  anywhere             anywhere            tcp dpt:imap2 
ACCEPT     tcp  --  anywhere             anywhere            tcp dpt:imaps 
ACCEPT     tcp  --  anywhere             anywhere            tcp dpt:ssh 
ACCEPT     tcp  --  anywhere             anywhere            tcp dpt:ftp 

Chain FORWARD (policy DROP)
target     prot opt source               destination         

Chain OUTPUT (policy DROP)
target     prot opt source               destination         
ACCEPT     all  --  anywhere             anywhere            
ACCEPT     all  --  anywhere             anywhere            state RELATED,ESTABLISHED 
ACCEPT     tcp  --  anywhere             anywhere            tcp dpt:www state NEW 
ACCEPT     tcp  --  anywhere             anywhere            tcp dpt:domain state NEW 
ACCEPT     udp  --  anywhere             anywhere            udp dpt:domain state NEW 
ACCEPT     tcp  --  anywhere             anywhere            tcp spt:www 
ACCEPT     tcp  --  anywhere             anywhere            tcp spt:https 
ACCEPT     tcp  --  anywhere             anywhere            tcp spt:smtp 
ACCEPT     tcp  --  anywhere             anywhere            tcp spt:ssmtp 
ACCEPT     tcp  --  anywhere             anywhere            tcp spt:pop3 
ACCEPT     tcp  --  anywhere             anywhere            tcp spt:pop3s 
ACCEPT     tcp  --  anywhere             anywhere            tcp spt:imap2 
ACCEPT     tcp  --  anywhere             anywhere            tcp spt:imaps 
ACCEPT     tcp  --  anywhere             anywhere            tcp spt:ssh 
ACCEPT     tcp  --  anywhere             anywhere            tcp spt:ftp

由于某种原因，攻击停止了，但我再也不能发送电子邮件了。

-P输出接受工作，但对我来说不是一个选项。

需要尽快帮助。谢谢

Answer 1

当ACCEPT对出站邮件连接时，您需要为dpt:smtp这样做。出站邮件连接的源端口是随机的，它不是smtp端口。

然而，更重要的是，您需要弄清楚是什么原因导致了攻击，如果您的系统被破坏了，您需要重新安装它，以确保入侵者不会继续使用此折衷方案。