Backscatter NDR spam messages received with clear original spam message attachment
I am running ZCS version: Release 8.0.1.GA.5438.UBUNTU12.64 UBUNTU12_64 FOSS edition.
Last week I started to reiceive a lot of ndr (~1 per minute) from different XYZ servers. Original message comes always from one ZZZ spamming host, but I cannot control it of course.
Almost all messages have attached "original" spam message, often already marked as SPAM on receiveing XYZ server. But - Zimbra antispam does not check/mark them as spam!
I know, there are little to do fighting backscatter spam - but i need at least understand - why or why not Zimbra checks attachments, but cannot mark them as spam?
Few examples in attachments: