RFC 5321: Simple Mail Transfer Protocol

This document is a specification of the basic protocol for Internet electronic mail transport. It consolidates, updates, and clarifies several previous…

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Outgoing relationships (2 related RFCs)

Updates — RFC 1123: Requirements for Internet Hosts - Application and Support
Obsoletes — RFC 2821: Simple Mail Transfer Protocol

Incoming relationships (71 related RFCs)

Showing 50 of 71 related RFCs.

Updated by, Normatively referenced by — RFC 7504: SMTP 521 and 556 Reply Codes
Normatively referenced by — RFC 5598: Internet Mail Architecture
Normatively referenced by — RFC 7435: Opportunistic Security: Some Protection Most of the Time
Normatively referenced by — RFC 6532: Internationalized Email Headers
Normatively referenced by — RFC 6530: Overview and Framework for Internationalized Email
Normatively referenced by — RFC 6409: Message Submission for Mail
Normatively referenced by — RFC 6531: SMTP Extension for Internationalized Email
Normatively referenced by — RFC 6186: Use of SRV Records for Locating Email Submission/Access Services
Normatively referenced by — RFC 5429: Sieve Email Filtering: Reject and Extended Reject Extensions
Normatively referenced by — RFC 6533: Internationalized Delivery Status and Disposition Notifications
Normatively referenced by — RFC 6651: Extensions to DomainKeys Identified Mail (DKIM) for Failure Reporting
Normatively referenced by — RFC 6652: Sender Policy Framework (SPF) Authentication Failure Reporting Using the Abuse Reporting Format
Normatively referenced by — RFC 7001: Message Header Field for Indicating Message Authentication Status
Normatively referenced by — RFC 7672: SMTP Security via Opportunistic DNS-Based Authentication of Named Entities (DANE) Transport Layer Security (TLS)
Normatively referenced by — RFC 6650: Creation and Use of Email Feedback Reports: An Applicability Statement for the Abuse Reporting Format (ARF)
Normatively referenced by — RFC 7643: System for Cross-domain Identity Management: Core Schema
Normatively referenced by — RFC 5408: Identity-Based Encryption Architecture and Supporting Data Structures
Normatively referenced by — RFC 7073: A Reputation Response Set for Email Identifiers
Normatively referenced by — RFC 7960: Interoperability Issues between Domain-based Message Authentication, Reporting, and Conformance (DMARC) and Indirect Email Flows
Normatively referenced by — RFC 8689: SMTP Require TLS Option
Normatively referenced by — RFC 8823: Extensions to Automatic Certificate Management Environment for End-User S/MIME Certificates
Normatively referenced by — RFC 5437: Sieve Notification Mechanism: Extensible Messaging and Presence Protocol (XMPP)
Normatively referenced by — RFC 6647: Email Greylisting: An Applicability Statement for SMTP
Normatively referenced by — RFC 6710: Simple Mail Transfer Protocol Extension for Message Transfer Priorities
Normatively referenced by — RFC 7293: The Require-Recipient-Valid-Since Header Field and SMTP Service Extension
Normatively referenced by — RFC 7505: A "Null MX" No Service Resource Record for Domains That Accept No Mail
Normatively referenced by — RFC 7601: Message Header Field for Indicating Message Authentication Status
Normatively referenced by — RFC 9493: Subject Identifiers for Security Event Tokens
Normatively referenced by — RFC 9598: Internationalized Email Addresses in X.509 Certificates
Normatively referenced by — RFC 6109: La Posta Elettronica Certificata - Italian Certified Electronic Mail
Normatively referenced by — RFC 6729: Indicating Email Handling States in Trace Fields
Normatively referenced by — RFC 6758: Tunneling of SMTP Message Transfer Priorities
Normatively referenced by — RFC 8098: Message Disposition Notification
Normatively referenced by — RFC 9228: Delivered-To Email Header Field
Normatively referenced by — RFC 9873: Additional Email Address Extension for the Extensible Provisioning Protocol (EPP)
Normatively referenced by — RFC 9989: Domain-Based Message Authentication, Reporting, and Conformance (DMARC)
Informatively referenced by — RFC 5322: Internet Message Format
Informatively referenced by — RFC 5890: Internationalized Domain Names for Applications (IDNA): Definitions and Document Framework
Informatively referenced by — RFC 6125: Representation and Verification of Domain-Based Application Service Identity within Internet Public Key Infrastructure Using X.509 (PKIX) Certificates in the Context of Transport Layer Security (TLS)
Informatively referenced by — RFC 6120: Extensible Messaging and Presence Protocol (XMPP): Core
Informatively referenced by — RFC 5706: Guidelines for Considering Operations and Management of New Protocols and Protocol Extensions
Informatively referenced by — RFC 5730: Extensible Provisioning Protocol (EPP)
Informatively referenced by — RFC 6709: Design Considerations for Protocol Extensions
Informatively referenced by — RFC 9325: Recommendations for Secure Use of Transport Layer Security (TLS) and Datagram Transport Layer Security (DTLS)
Informatively referenced by — RFC 5927: ICMP Attacks against TCP
Informatively referenced by — RFC 7624: Confidentiality in the Face of Pervasive Surveillance: A Threat Model and Problem Statement
Informatively referenced by — RFC 6528: Defending against Sequence Number Attacks
Informatively referenced by — RFC 7303: XML Media Types
Informatively referenced by — RFC 5617: DomainKeys Identified Mail (DKIM) Author Domain Signing Practices (ADSP)
Informatively referenced by — RFC 6943: Issues in Identifier Comparison for Security Purposes