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iptables + postfix 无法发送电子邮件

tag-icon • tag-icon debian iptables postfix firewall
iptables + postfix 无法发送电子邮件

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。我不太懂安全，所以我找了一些教程，用 iptables 关闭了所有未使用的端口。

这是我的 iptables 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，但我无法再发送电子邮件。

-P OUTPUT ACCEPT 有效，但对我来说不是一个选项。

需要尽快帮助。谢谢

答案1

在建立出站邮件连接时ACCEPT，您需要对 进行此操作dpt:smtp。出站邮件连接的源端口是随机的，而不是端口smtp。

但更重要的是，您需要弄清楚是什么导致了攻击，如果您的系统受到了损害，您需要重新安装它以确保入侵者无法利用这种损害。

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