RFC 5322
Learn what RFC 5322 defines for email message formatting and how DMARCeye uses its header standards to analyze and align authentication results.
What is the RFC 5322 standard?
RFC 5322 is the Internet Engineering Task Force (IETF) standard that defines the format of email messages, including headers, fields, and message structure. Published in October 2008, it updates and replaces RFC 2822, standardizing how email content is composed, transmitted, and interpreted across mail systems. RFC 5322 works alongside RFC 5321, which governs message transport through SMTP.
This standard ensures consistency and compatibility between mail clients and servers by defining syntax rules for message headers, body text, and encoding. Every modern email system uses RFC 5322-compliant formatting, making it one of the most important documents in the email ecosystem.
Key Components of RFC 5322
RFC 5322 defines several crucial aspects of email message structure, including:
- Header fields: Such as “From,” “To,” “Subject,” “Date,” and “Message-ID.”
- Message body: The plain text or multipart content of the email.
- Syntax rules: Requirements for line length, character encoding, and whitespace handling.
- Message identifiers: Unique IDs used for threading and message tracking.
Example of an RFC 5322-compliant header:
From: user@example.com
To: admin@example.org
Subject: Test Message
Date: Tue, 22 Oct 2024 14:00:00 +0000
Message-ID: <abc123@example.com>Importance in Authentication
RFC 5322 headers play a key role in DMARC and related protocols. The “Header From” field is used to determine domain alignment for DMARC validation. SPF checks focus on the “Envelope From” from RFC 5321, while DKIM and DMARC use RFC 5322’s header fields for identity verification.
Understanding RFC 5322 is essential for diagnosing authentication failures and ensuring message compliance across all systems.
RFC 5322 and DMARCeye
DMARCeye leverages RFC 5322 standards to accurately parse and analyze message headers during authentication checks. The platform identifies header inconsistencies that may cause misalignment or false rejections under DMARC.
By mapping envelope data from RFC 5321 to header data from RFC 5322, DMARCeye provides complete visibility into how messages are authenticated, ensuring accurate diagnostics and improved deliverability.
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To learn more about DMARC and DMARC-related terms, explore the DMARCeye Glossary.