Question about Microsoft xlsx/docx/pptx files

[Damian]

> What, then, is your recommended solution which generally blocks .zip files but allows the xlsx, docx and pptx file suffixes?

It was not my intention to recommend something. Because file(1) and amavis are not perfect, banned_* is a wish list. As you have
already observed, the outcome deviates from the wishes right now, and I pointed out that it still might deviate from them using
your proposed whitelisting. I have no suggestion how to align expressed wishes with the outcome in all corner cases. That said, a
recommendation would then mean to make you change wishes, even I they were justified or originated from a third party you have no
control over. Personally, I do not block archives.