ARC (Authenticated Received Chain)
ARC preserves SPF and DKIM results when email is forwarded, so the final receiver can still trust authentication that a hop would otherwise break.
Product & Engineering · July 17, 2026 · 1 min read
ARC (Authenticated Received Chain) is an email authentication standard that preserves the original SPF and DKIM results when a message is forwarded through a mailing list or security gateway.
Forwarding can break SPF and DKIM by changing the message or the sending server. ARC records the original authentication result so the final receiver can still trust it. It builds on SPF, DKIM, and DMARC rather than replacing them.
See the full guide: Related: the authentication guide.
Resources in this guide
| Property | Value |
|---|---|
| Purpose | Preserve auth across forwarding |
| Depends on | SPF, DKIM, DMARC |
| Required? | No, but helpful for forwarded mail |
Frequently asked questions
Do I need ARC?
ARC is not required for deliverability. It mainly helps when your mail is forwarded through mailing lists or gateways that would otherwise break SPF and DKIM.
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