I just started learning Zimbra, recently we have received a lot of fake emails from like xxxx@abc.com with IP (195.xxx.xx.xxx), the system fail to reverse lookup the ip address to it's domain, however it still pass the message to the receiver which I doesn't want to, so I would like to know if:

1. There is notification setup so that when we know when we receive this kind of message.
2. To block the message directly when the reverse lookup fail.

Thanks so much in advance.