SPF, DKIM, and DMARC are complementary technologies that work together to authenticate emails. SPF allows the domain owner to specify which IP addresses are permitted to send emails on behalf of the domain. DKIM adds a digital signature to each email, which the receiving server can verify. DMARC builds on SPF and DKIM by providing a mechanism for receiving servers to report back to the domain owner about the authentication status of their emails. Together, these methods provide a robust framework for email authentication.