What is ARC?

ARC, also known as Authenticated Received Chain, is defined in RFC 8617. ARC does not authenticate a message by itself. Instead it preserves the authentication results seen by upstream servers so that receivers can understand what happened earlier in the message’s journey.

ARC builds on Authentication Results as defined in RFC 8601, which provides the structured format for SPF, DKIM, and DMARC evaluation. ARC carries these results forward in a verifiable way.

Think of ARC as a sealed logbook that travels with the message from harbor to harbor. Each stop adds its own entry, preserving the history of what happened upstream. It never overrides DMARC or forces acceptance. It simply provides truthful history.

Was this answer helpful?

Thanks for your feedback!