we are using Ironport (virtual appliance) and one email gets changed by the email gateway. The problematic message is a HTML email that is sent from a qmail MTA system. When the email flows through the Ironport gateway the HTML content isn't displayed correctly - raw HTML code is displayed.
I've tried to disable all the email Policies that could potenally influence the email but the problem persists. Additionally I've checked the source of the email and the only difference between the two emails is in the header - the email that goes through Ironport has one additional hop under "Received" part.
Do you have any suggestions what should be additionally checked on the Ironport virtual appliance ?
Would you be able to provide what you are seeing? Our OS/Appliance does not change the messages in any way - so, it is not changing the email itself, unless you are doing so with a content filter or message filter. What does the message tracking show for emails that have this issue?
I've created a TEST Mail Flow Policy that has all the security features disabled (Spam Detection, Virus Protection etc.). I checked with message tracking and the MFP is successfully used when the problematic email hits the appliance. Other stuff under message tracking also seem to be ok.
I've tried to send the email to gmail and also to the same MTA but this time bypassing Ironport, both times the email was displayed correctly.