You want to know the scope of the impact of mitigation request in DDI 3.8.
Yes, it does. DDI will only send mitigation request/clean task to Internal IP range. Internal hosts are hosts that belongs to a Network Group. This is defined in the Administration > Network Groups and Assets > Network Groups section of the Web Console. So if an IP is not included in any Network Group, DDI will not send mitigation request to it.
No, the Network Zone settings will not impact the mitigation request.