DMARC, or Domain-based Message Authentication, Reporting & Conformance, is an email authentication protocol that works alongside existing technologies like Sender Policy Framework (SPF) and DomainKeys Identified Mail (DKIM).
Why is DMARC Needed?
While SPF verifies if an email comes from an authorised IP address, and DKIM checks for a valid digital signature, neither guarantees the sender's identity definitively. DMARC closes this gap.
How Does DMARC Work?
- Policy Setup: Organisations publish a DMARC record with their domain name. This record specifies their policy on how to handle emails that fail SPF or DKIM checks.
- Authentication & Reporting: When an email arrives, the recipient server performs SPF and DKIM checks. It then checks the sender's DMARC record for instructions.
- Enforcing Policy: Based on the DMARC policy ("reject," "quarantine," or "none"), the recipient server handles the email (block, spam folder, or allow delivery).
- Reporting: Receiving mail servers can send reports to the domain owner summarising authentication results. This helps identify potential spoofing attempts and improve email security.
Benefits of DMARC
- Protects Against Spoofing: DMARC helps prevent cybercriminals from disguising their emails as coming from your domain.
- Reduces Phishing Attacks: Makes it harder for phishers to trick recipients into clicking malicious links.
- Improves Email Security: Provides valuable insights into email authentication attempts for better security measures.
By implementing DMARC, organisations can significantly enhance their email security posture and protect themselves and their recipients from malicious attacks.
