I have customers who are asking about implementing DMARC and DKIM. Currently, hosted exchange doesn't support it, and I would like to suggest that you add that option for us to be able to implement it for our customers.
Imran Ali commented
I Believe that Implementing DMARC (Domain-based Message Authentication Reporting and Conformance) is the best way to defend your customers, your brand, and your employees from phishing and spoofing attacks.
DMARC is built upon two other authentication protocols: SPF (Sender Policy Framework) and DKIM (DomainKeys Identified Mail).