What is the advantage of DMARC over SPF?
SPF is simply a DNS entry that functions as a whitelist of IP addresses authorised to send mail on a domain’s behalf. DMARC, on the other hand, actually gives ISPs instructions on how to handle mail that fails SPF and DKIM authentication. It also allows for senders to receive daily reports containing information like the dates and times these emails were sent and the outcome of their authentication. This information is imperative to monitoring the effectiveness of a domain’s security policies.