Level: Advanced
ARC preserves authentication results as a message passes through intermediate systems, like mailing lists or forwarding services, solving a specific problem that DMARC alone creates for legitimately forwarded mail.
Forwarding Commonly Breaks Standard Authentication
When a message is forwarded or relayed through an intermediate system, the original SPF and sometimes DKIM results can break, causing a legitimately sent message to fail DMARC at its final destination.
ARC Creates a Verifiable Chain of Custody
Each intermediate system that participates in ARC adds a signed set of authentication results to the message, allowing the final receiving server to see the original authentication outcome despite the forwarding.
It's Particularly Relevant for Mailing Lists and Forwarding Services
Organizations running mailing lists or forwarding services are the primary parties responsible for implementing ARC, since they're the intermediate step where standard authentication would otherwise break.
Next step: Use the Find DNS Records to check your domain's authentication setup as part of evaluating whether ARC support is relevant to your specific sending scenarios.