On Prem Module on Big-IP or CE to do Source NAT for Traffic proxied by XC DDoS Scrubbing Center for visibility of Source IP based on Sync with XC to give visibility for other security tools that have Threat Intel based on Source IP like mail gateways & NGFW's.

Not all security tools support Proxy Protocol or XFF and not all traffic is Web Traffic.

We can't protect Mail Gateways from DDoS Attacks using Proxy Mode Scrubbing Center since we will lose the AntiSpam Features and Our Perimeter Security tools doesn't have any traffic Visibility on Source IP's