ARC (Authenticated Received Chain) is an email-authentication standard that preserves the results of SPF, DKIM and DMARC checks when a message is forwarded or passes through an intermediary such as a mailing list. It lets the final receiving server see that authentication passed at an earlier hop, even if forwarding would normally break it.
How ARC works
When a server that supports ARC receives an authenticated message and forwards it, it adds a set of ARC headers that record the original SPF, DKIM and DMARC results and seals them with its own signature. The next server can then trust that earlier verdict. This matters because forwarding often changes a message enough to break DKIM or fail SPF, which would otherwise cause a legitimate email to be rejected under a strict DMARC policy.
Why ARC matters
ARC reduces false rejections of forwarded mail, so newsletters relayed through lists or forwarding services still reach the inbox. It complements rather than replaces email authentication: you still publish SPF, DKIM and DMARC, and ARC carries their results across hops. Learn what SPF is, see how to configure DMARC with Mailpro, or set up your DMARC record.
Mailpro and authentication
Authentication that survives forwarding
Mailpro signs every campaign with SPF and DKIM and helps you set a DMARC policy, so your mail authenticates cleanly and stays trusted even when it's forwarded.