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Authentication

Identity signals for email: SPF, DKIM, DMARC, and related controls.

Reading time:: 5 min
Difficulty:: Intermediate
Estimated duration:: 5 min
Prerequisites:: None
Last updated:: 2026-07-15
Author:: empire

Definition

Identity signals for email: SPF, DKIM, DMARC, and related controls.

SPFSender Policy Framework — authorizes hosts that may send for a domain.
DKIMDomainKeys Identified Mail — cryptographic signatures for message integrity.
DMARCDomain-based Message Authentication, Reporting, and Conformance.
ARCAuthenticated Received Chain — preserves auth results across intermediaries.
BIMIBrand Indicators for Message Identification — logos for supporting inboxes.
MTA-STSSMTP MTA Strict Transport Security for inbound TLS policy.
TLS-RPTSMTP TLS Reporting for encrypted delivery failure reports.

Open step-by-step: Audit multi-domain authenticationReview authentication across a domain portfolio.
Open step-by-step: Authenticate a new domainPublish SPF, DKIM, and DMARC for a new sending domain and verify authentication before warmup.
Open step-by-step: Check authenticationRegularly verify SPF, DKIM, and DMARC alignment and report pipelines.

Empire Services

Domain authentication auditStructured review of SPF, DKIM, DMARC, and related controls.

Where do you want to go next?

DNSDomain Name System — the lookup fabric email authentication depends on.

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