Hi Roberto,

Greetings..!!

I am holding a doubt regarding NDR while evaluating Spam Filter for our Mail Server. Here it goes..

In SpamFilter > Configuration > Options , there is a option to allow/block Empty "Mail From" .

We use MS SMTP for Outgoing Mails and another SMTP for Only Receiving Mails ( MX record in DNS points to this).

Now when I enable Empty "Mail From", the NDR sent by MS SMTP are being simply rejected by SpamFilter and also some other mails received from outer domains with Empty Mail From , where as RFC 1123 5.2.9 (More information points to RFC-821 Page 15) says that A empty reverse path MUST be supported.

I realise that SpamFilter just acts as a Filtering Proxy for my Incoming SMTP server and ofcourse validates Incoming mail based on the settings & MAPS lookups.

If I uncheck the Empty "Mail From" , the SpamFilter may allow NDR generated by my MS SMTP and also other mails with Empty Mail From.

How do i make sure that only NDR related mails alone are accepted by SpamFilter and reject other Emails with empty Mail From. I am using v1.2.0.178.

Best Regards

Thirumal Reddy M

System Admin / SQL DBA.