Using the admin console / Policies
General settings
How browsers check downloads, not what they block.
- Check the content of every download: off, only ZIPs are fetched again and checked; on, every download is, which catches disguised programs at the cost of a second request.
- Documents allowed inside ZIPs: Office documents and EPUB books are ZIPs inside; these count as ordinary files.
- Advanced, limits: sizes and times for checks, such as the largest ZIP that is checked. Only values you change are saved.