BLOCK OUTBOUND MESSAGES

Question

We have PireMessage 3.0.2 installed on an SBS 2003 with Exchange .

Can we stop outbound traffic coming from not legitimate internal e-mail senders ?

we can't find any settings for outgoing antispam settings ...

This thread was automatically locked due to age.

Reginald · Accepted Answer

Hi,

Exchange's auto-forwarding behaviour is as below, in this example John has an auto-forward to Richard:

1. Message sent from Bob to John 
 2. Message auto-forwarded to Richard though sender is Bob not John 
 3. Message received by Richard, sender listed as Bob

In other words, Exchange keeps the original envelope sender for auto-forwarded messages.

So the scenario in the screenshot is possible with the issue in http://www.sophos.com/support/knowledgebase/articl​e/35590.html , as messages could be auto-forwarded with non-existing users (kbeswlf@ , kkdkxb@, gdk@ etc).

If messages are not being auto-forwarded and are in fact being sent from an external domain to an external domain then this would suggest the server may be an open relay http://en.wikipedia.org/wiki/Open_mail_relay , Microsoft have an article for diagnosing this type of issue http://support.microsoft.com/kb/895853 .

Thanks :5287