To set a data quota on outgoing mail messages, in the Filr Administration Console > System > Email dialog, specify the quota limit in the Maximum Size for the Sum of All File Attachments and the Maximum Size of Each File Attachment fields.
By default, there is no limit to the size of attached files. You can leave the fields blank to retain the default of no limit.
To restrict any attachments from being sent, specify 0 in each field.
Click Apply to save the settings, then click Close.