# Technical specifications repository

On this page, you find references to the authoritative technical specifications followed by dmarced to ensure secure email delivery via DKIM, SPF, and DMARC.

## DMARC

The current DMARC standard, published in May 2026, is made up of 3 RFC publications: The first one laying out the foundation of how DMARC operates, the second covering DMARC aggregate reports, and the third one covering failure reporting.

- [RFC 9989: Domain-Based Message Authentication, Reporting, and Conformance (DMARC)](https://datatracker.ietf.org/doc/html/rfc9989)
- [RFC 9990: Domain-Based Message Authentication, Reporting, and Conformance (DMARC) Aggregate Reporting](https://datatracker.ietf.org/doc/html/rfc9990)
- [RFC 9991: Domain-Based Message Authentication, Reporting, and Conformance (DMARC) Failure Reporting](https://datatracker.ietf.org/doc/html/rfc9991)

The three RFCs above replace the following specification of DMARC. It is still relevant as many participants may not have updated their software to support the changes.

-  [RFC 7489: Domain-based Message Authentication, Reporting, and Conformance (DMARC)](https://datatracker.ietf.org/doc/html/rfc7489)

## DKIM

- [RFC 6376: DomainKeys Identified Mail (DKIM) Signatures](https://datatracker.ietf.org/doc/html/rfc6376)

## SPF

- [RFC 7208: Sender Policy Framework (SPF) for Authorizing Use of Domains in Email, Version 1](https://datatracker.ietf.org/doc/html/rfc7208)

## Mail

- [RFC 5321: Simple Mail Transfer Protocol](https://datatracker.ietf.org/doc/html/rfc5321)
- [RFC 7505: A "Null MX" No Service Resource Record for Domains That Accept No Mail](https://datatracker.ietf.org/doc/html/rfc7505)