Attachment & MIME Filter

Attachment & MIME Filter – Control of Attachments and File Types

The Attachment & MIME Filter from Conbool protects your mailboxes from malicious or unwanted files.
You can precisely define which file types are allowed, inspected, or blocked.

Enable Attachment Checking

• Function: Enables or disables the general inspection of attachments.
• Setting:
  • Toggle to the right (blue) → active
  • Toggle to the left (gray) → disabled

Enable ZIP/RAR Analysis

• Function: Unpacks compressed archives (e.g., .zip, .rar) and inspects their contents as well.
  • Increases security by detecting hidden malicious files
  • May slightly affect processing speed
• Setting:
  • Toggle to the right (blue) → active
  • Toggle to the left (gray) → disabled

Maximum Attachment Size (MB)

• Function: Defines the maximum allowed size for email attachments.
• Setting: Numeric field (size in MB)
• Example: 50 → Attachments up to 50 MB allowed

Blocked File Types (Predefined)

• Function: Selection of common file extensions that are blocked by default (e.g., .exe, .js).
• Setting:
  • Display of the number of selected types (e.g., "3 selected")
  • Selected extensions appear as tags (.exe, .js, ...)
  • Selection via dropdown or checkboxes

Custom File Types

• Function: Individual extension of the block list with additional file extensions.
• Setting:
  • Text field: Enter the extension (starting with a dot, e.g., .sh, .bat)
  • Button: Adds the extension to the block list
  • List: Shows already added extensions with a delete option (trash icon)

Filename Patterns

• Function: Allows blocking attachments based on filename patterns.
• Setting:
  • Text field: Enter a pattern (e.g., invoice_*.exe, *.scr)
  • Button: Adds the pattern to the list
  • List: Shows already added patterns with a delete option (trash icon)

See Also

• Policies – Apply attachment filters specifically to certain users or groups through policies.
• Feature Overview – Overview of all MailGuard modules.