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RFC 5598 - Internet Mail Architecture

Status of This Memo​

This memo provides information for the Internet community. It does not specify an Internet standard of any kind. Distribution of this memo is unlimited.

Copyright (c) 2009 IETF Trust and the persons identified as the document authors. All rights reserved.

Abstract​

Over its thirty-five-year history, Internet Mail has changed significantly in scale and complexity, as it has become a global infrastructure service. These changes have been evolutionary, rather than revolutionary, reflecting a strong desire to preserve both its installed base and its usefulness. To collaborate productively on this large and complex system, all participants need to work from a common view of it and use a common language to describe its components and the interactions among them. But the many differences in perspective currently make it difficult to know exactly what another participant means. To serve as the necessary common frame of reference, this document describes the enhanced Internet Mail architecture, reflecting the current service.

Table of Contents​

  • 1. Introduction
    • 1.1. History
    • 1.2. The Role of This Architecture
    • 1.3. Document Conventions
  • 2. Responsible Actor Roles
    • 2.1. User Actors
      • 2.1.1. Author
      • 2.1.2. Recipient
      • 2.1.3. Return Handler
      • 2.1.4. Mediator
    • 2.2. Message Handling Service (MHS) Actors
      • 2.2.1. Originator
      • 2.2.2. Relay
      • 2.2.3. Gateway
      • 2.2.4. Receiver
    • 2.3. Administrative Actors
  • 3. Identities
    • 3.1. Mailbox
    • 3.2. Scope of Email Address Use
    • 3.3. Domain Names
    • 3.4. Message Identifier
      • 3.4.1. Message-ID
      • 3.4.2. ENVID
  • 4. Services and Standards
    • 4.1. Message Data
      • 4.1.1. Envelope
      • 4.1.2. Header Fields
      • 4.1.3. Body
      • 4.1.4. Identity References in a Message
    • 4.2. User-Level Services
      • 4.2.1. Message User Agent (MUA)
      • 4.2.2. Message Store (MS)
    • 4.3. MHS-Level Services
      • 4.3.1. Message Submission Agent (MSA)
      • 4.3.2. Message Transfer Agent (MTA)
      • 4.3.3. Mail Delivery Agent (MDA)
    • 4.4. Transition Modes
    • 4.5. Implementation and Operation
  • 5. Mediators
    • 5.1. Alias
    • 5.2. ReSender
    • 5.3. Mailing Lists
    • 5.4. Gateways
    • 5.5. Boundary Filter
  • 6. Considerations
    • 6.1. Security Considerations
    • 6.2. Internationalization
  • 7. References
    • 7.1. Normative References
    • 7.2. Informative References
  • Appendix A. Acknowledgments
  • Author's Address