SPF, DKIM, and DMARC are all email authentication protocols, but they serve different purposes:
1. SPF (Sender Policy Framework): Allows domain owners to specify which IP addresses are authorized to send emails on behalf of their domain. It helps to prevent email spoofing.
2. DKIM (DomainKeys Identified Mail): Adds a digital signature to emails, which can be verified by the receiving email server to ensure the email has not been altered during transit and that it was sent by an authorized sender.
3. DMARC (Domain-based Message Authentication, Reporting & Conformance): Builds on SPF and DKIM by adding a layer of policy and reporting. It allows domain owners to specify how to handle emails that fail SPF or DKIM checks and provides visibility into email authentication results through reports.
Together, these protocols enhance email security and help to prevent email fraud and phishing.