On restricted attachment name

You can add an attachment name to be blocked. These attachments could be media (music or movies) sent within an organization, and you may have a policy of restricting or monitoring them, rather than automatically deleting them. You can optionally specify a size limit (if an attachment with the relevant name exceeds the size limit, the attachment is blocked). You can also block all files with multiple extensions, and specify exceptions to that rule.
Note This function will check the attachment name only. If the sender has altered an otherwise restricted attachment name, PureMessage for Microsoft Exchange will not detect it, unless that attachment type is selected on the Attachment types tab.

Click Configuration > Transport (SMTP) scanning policy > Content. On the Content filtering screen, in the On restricted attachment bar, click Define. In the Restricted attachment type dialog box, click the Attachment names tab.

Click Add to enter an Attachment name to block. You can use the wildcards '*' and '?', for example *.pdf. Optionally, enter a size limit in MB.

Click Remove to remove a highlighted attachment name and size.

Check the Block all files with multiple extensions except check box,click Add to enter one or more exceptions if required.

Click Edit to edit a highlighted exception.

Click Remove to remove a highlighted exception.

Click Restore defaults to restore default settings.

Click OK to save your changes, and return to the Content filtering screen.
Note From the Manage changes menu, click Save changes to save your configuration.

If you want to allow certain restricted attachments, follow the steps in Exclude restricted attachments from filtering.