SPF (Sender Policy Framework): SPF is an email authentication method that allows the owner of a domain to specify which mail servers are permitted to send email on behalf of that domain.
DKIM (DomainKeys Identified Mail): DKIM is an email authentication method that allows the receiver to check that an email claimed to have come from a specific domain was indeed authorized by the owner of that domain.
DMARC Policy: The DMARC policy is a set of instructions published in the domain's DNS records that tells email receivers how to handle emails that fail SPF and/or DKIM checks. The policy can be set to monitor, quarantine, or reject such emails.
DMARC Reporting: DMARC provides two types of reports: aggregate reports (RUA) and forensic reports (RUF). These reports give domain owners insights into who is sending email on behalf of their domain and how their email is being authenticated.
Email is Sent: An email is sent from a domain that has a DMARC policy published in its DNS records.
SPF and DKIM Checks: The receiving mail server performs SPF and DKIM checks to verify the authenticity of the email.
DMARC Alignment: DMARC checks if the domain in the 'From' header matches the domain in the SPF and DKIM checks. This is known as “alignment.”
Policy Enforcement: Based on the DMARC policy (none, quarantine, or reject), the receiving server decides what to do with emails that fail the checks.
None: Monitor and report, but take no action.
Quarantine: Mark the email as suspicious and place it in the spam/junk folder.
Reject: Reject the email outright, preventing it from reaching the recipient.
Reporting: The receiving server sends DMARC reports back to the domain owner, providing information on emails that passed or failed the DMARC checks.
Protects Against Email Spoofing: DMARC helps prevent attackers from sending email from a domain without authorization, reducing the risk of phishing and other email-based attacks.
Improves Email Deliverability: By ensuring that legitimate emails pass SPF, DKIM, and DMARC checks, it improves the likelihood that these emails will be delivered to the recipient's inbox rather than being marked as spam.
Visibility and Monitoring: DMARC reports provide domain owners with detailed insights into email traffic and authentication results, allowing them to monitor and improve their email security.
Brand Protection: DMARC helps protect the domain owner’s brand by preventing unauthorized use of their domain in email communications.
Publish DMARC Record with EmailConsul: Add a DMARC record to your DNS. The record specifies the policy and where to send reports and available via the portal under the Settings → Add Domain. Example DMARC record: _dmarc.example.com. IN TXT v=DMARC1; p=none; rua=mailto:[email protected]
Monitor Reports: Start with a policy of none to monitor email traffic and gather data without impacting email delivery. Review DMARC reports to understand who is sending email on behalf of your domain and to identify any authentication issues.
Adjust Policy: Gradually move from none to quarantine and finally to reject as you gain confidence in your email authentication setup.
Maintain and Update: Regularly review DMARC reports and update your SPF and DKIM records as needed to maintain a robust email security posture.
By implementing DMARC, organizations can significantly enhance their email security, protect their brand reputation, and improve email deliverability.