RFC 9990 / START HERE
DMARC aggregate reports, before the details
DMARC aggregate reporting
DMARC is Domain-based Message Authentication, Reporting, and Conformance. Aggregate reports summarize how groups of messages using a domain performed in authentication checks.
The idea in one picture
Receivers observe mail results
Results are grouped into reports
The domain owner reviews patterns
A simplified picture of the idea; the chapters explain the actual mechanisms.
Why it exists
Domain owners need a broad picture of legitimate senders, misconfiguration, and possible abuse without inspecting one message at a time.
A familiar example
A domain owner receives a periodic summary showing sending sources and their authentication results.
Helpful background
You can start here without reading another RFC. If these ideas are unfamiliar, these short introductions may help.
What you’ll learn next
Begin with chapter one, or choose a topic.
- Aggregate counts into rowsAn aggregate report summarizes observed message streams rather than attaching individual message contents.→
- XML report anatomyThe XML document carries metadata, published policy, and repeated records.→
- Request and recipient consentrua identifies aggregate report destinations, and external destinations require verification.→
- Delivery and duplicatesA retried report must retain its identity so the recipient can recognize duplicate information.→
- Privacy and untrusted reportsEven aggregate reports can disclose traffic metadata, and report content is untrusted input.→
This introduction explains RFC 9990 (2026). Read the original RFC ↗