How to prevent emails from being flagged as Spoof by CAS

Customer can prevent emails from being flagged as spoofs by CAS, when routing mail through SonicWall Hosted Email Security (or any other third party vendor) first, by adding HES hostname 'snwlhosted.com' (or third party hostname or IPs) to 'Configure Anti-Impersonation and Phishing Confidence-Level' option by adding new policy to 'Office 365 Mail Threat Detection'.