Comment by mgcunha

Neither DKIM nor SPF provide domain owners with a verifiable disposition policy and monitoring. You should deploy SPF, DKIM and DMARC together. At that point either SPF or DKIM may pass but if the passing SPF/DKIM domain(s) don't match the DMARC domain the message isn't authenticated. Unlike SPF, DMARC will load its policy using the From: header, and thus ensure alignment between envelope-From and From: header (for SPF), or DKIM domain and From: header.