Chapter 10 Install and System Administration for FortiOS 5.0 : Advanced concepts : Replacement messages list : Spam replacement messages
  
Spam replacement messages
The FortiGate unit adds the Spam replacement messages listed in the following table to SMTP server responses if the email message is identified as spam and the spam action is discard. If the FortiGate unit supports SSL content scanning and inspection these replacement messages can also be added to SMTPS server responses.
See Also
Modifying replacement messages
Replacement messages list
Adding images to replacement messages