My Messaging Server installation (version 6.3-7.04) is seeing an excessive amount of spam whereby the message headers seem to indicate that the message is coming from my mail server's own IP address when in fact it is not. I have used snoop & wireshark to verify that the messages are actually coming from an external IP, but when I look at the message headers of one of the offending messages, the Received header looks like this:
Received: from 146.151.48.136 ([w.x.y.z])
Where "w.x.y.z" is my server's IP!
The rule in my mappings file defines my IPs as internal, and hence, relaying is being allowed.
How can I defeat this method of circumventing my anti-spamming policies?
Thanks,
Bill