Classes of Service and accounts can be configured with rules to reject mail with specific attachment types, to convert attachments to HTML for viewing, and to disable viewing files attached to mail messages.
When attachment settings are configured in Global Settings, the global rule takes precedence over COS and Account settings.
The attachment settings are as follows:
Attachments are viewed in HTML regardless of COS. Email attachments can only be viewed in HTML.
Attachments are viewed according to COS. This global settings states the COS sets the rules for how email attachments are viewed.
Reject messages with attachment extension lets you select which file types are unauthorized for all accounts. The most common extensions are listed. You can also add different extension types to the list. Messages with those type of files attached are rejected and the sender gets a bounce notice. The recipient does not get the mail message and is not notified.