RFC 2821: Simple Mail Transfer Protocol

This document is a self-contained specification of the basic protocol for the Internet electronic mail transport. [STANDARDS-TRACK]

Read RFC 2821 on the RFC Editor

Outgoing relationships (30 related RFCs)

Obsoletes, Informative reference — RFC 821: Simple Mail Transfer Protocol
Obsoletes, Informative reference — RFC 974: Mail routing and the domain system
Obsoletes — RFC 1869: SMTP Service Extensions
Informative reference — RFC 1034: Domain names - concepts and facilities
Informative reference — RFC 2045: Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies
Informative reference — RFC 822: STANDARD FOR THE FORMAT OF ARPA INTERNET TEXT MESSAGES
Informative reference — RFC 2234: Augmented BNF for Syntax Specifications: ABNF
Informative reference — RFC 1123: Requirements for Internet Hosts - Application and Support
Informative reference — RFC 2047: MIME (Multipurpose Internet Mail Extensions) Part Three: Message Header Extensions for Non-ASCII Text
Informative reference — RFC 2822: Internet Message Format
Informative reference — RFC 2373: IP Version 6 Addressing Architecture
Informative reference — RFC 1939: Post Office Protocol - Version 3
Informative reference — RFC 1847: Security Multiparts for MIME: Multipart/Signed and Multipart/Encrypted
Informative reference — RFC 2440: OpenPGP Message Format
Informative reference — RFC 2633: S/MIME Version 3 Message Specification
Informative reference — RFC 1894: An Extensible Message Format for Delivery Status Notifications
Informative reference — RFC 2060: Internet Message Access Protocol - Version 4rev1
Informative reference — RFC 1652: SMTP Service Extension for 8bit-MIMEtransport
Informative reference — RFC 1893: Enhanced Mail System Status Codes
Informative reference — RFC 2979: Behavior of and Requirements for Internet Firewalls
Informative reference — RFC 1891: SMTP Service Extension for Delivery Status Notifications
Informative reference — RFC 937: Post Office Protocol: Version 2
Informative reference — RFC 2476: Message Submission
Informative reference — RFC 2298: An Extensible Message Format for Message Disposition Notifications
Informative reference — RFC 1830: SMTP Service Extensions for Transmission of Large and Binary MIME Messages
Informative reference — RFC 1985: SMTP Service Extension for Remote Message Queue Starting
Informative reference — RFC 1047: Duplicate messages and SMTP
Informative reference — RFC 1176: Interactive Mail Access Protocol: Version 2
Informative reference — RFC 2920: SMTP Service Extension for Command Pipelining
Informative reference — RFC 1056: PCMAIL: A distributed mail system for personal computers

Incoming relationships (45 related RFCs)

Updated by — RFC 5336: SMTP Extension for Internationalized Email Addresses
Obsoleted by — RFC 5321: Simple Mail Transfer Protocol
Normatively referenced by — RFC 5228: Sieve: An Email Filtering Language
Normatively referenced by — RFC 4409: Message Submission for Mail
Normatively referenced by — RFC 3801: Voice Profile for Internet Mail - version 2 (VPIMv2)
Normatively referenced by — RFC 4408: Sender Policy Framework (SPF) for Authorizing Use of Domains in E-Mail, Version 1
Normatively referenced by — RFC 4954: SMTP Service Extension for Authentication
Normatively referenced by — RFC 4871: DomainKeys Identified Mail (DKIM) Signatures
Normatively referenced by — RFC 3459: Critical Content Multi-purpose Internet Mail Extensions (MIME) Parameter
Normatively referenced by — RFC 3885: SMTP Service Extension for Message Tracking
Normatively referenced by — RFC 3887: Message Tracking Query Protocol
Normatively referenced by — RFC 5248: A Registry for SMTP Enhanced Mail System Status Codes
Normatively referenced by — RFC 3696: Application Techniques for Checking and Transformation of Names
Normatively referenced by — RFC 4405: SMTP Service Extension for Indicating the Responsible Submitter of an E-Mail Message
Normatively referenced by — RFC 4550: Internet Email to Support Diverse Service Environments (Lemonade) Profile
Normatively referenced by — RFC 5275: CMS Symmetric Key Management and Distribution
Normatively referenced by — RFC 3773: High-Level Requirements for Internet Voice Mail
Normatively referenced by — RFC 3848: ESMTP and LMTP Transmission Types Registration
Normatively referenced by — RFC 4141: SMTP and MIME Extensions for Content Conversion
Normatively referenced by — RFC 4356: Mapping Between the Multimedia Messaging Service (MMS) and Internet Mail
Normatively referenced by — RFC 4524: COSINE LDAP/X.500 Schema
Normatively referenced by — RFC 4823: FTP Transport for Secure Peer-to-Peer Business Data Interchange over the Internet
Normatively referenced by — RFC 3675: .sex Considered Dangerous
Normatively referenced by — RFC 3865: A No Soliciting Simple Mail Transfer Protocol (SMTP) Service Extension
Normatively referenced by — RFC 4161: Guidelines for Optional Services for Internet Fax Gateways
Normatively referenced by — RFC 4239: Internet Voice Messaging (IVM)
Informatively referenced by — RFC 5598: Internet Mail Architecture
Informatively referenced by — RFC 5730: Extensible Provisioning Protocol (EPP)
Informatively referenced by — RFC 6530: Overview and Framework for Internationalized Email
Informatively referenced by — RFC 3730: Extensible Provisioning Protocol (EPP)
Informatively referenced by — RFC 5218: What Makes for a Successful Protocol?
Informatively referenced by — RFC 4038: Application Aspects of IPv6 Transition
Informatively referenced by — RFC 4686: Analysis of Threats Motivating DomainKeys Identified Mail (DKIM)
Informatively referenced by — RFC 4930: Extensible Provisioning Protocol (EPP)
Informatively referenced by — RFC 3502: Internet Message Access Protocol (IMAP) - MULTIAPPEND Extension
Informatively referenced by — RFC 5022: Media Server Control Markup Language (MSCML) and Protocol
Informatively referenced by — RFC 3805: Printer MIB v2
Informatively referenced by — RFC 3676: The Text/Plain Format and DelSp Parameters
Informatively referenced by — RFC 3395: Remote Network Monitoring MIB Protocol Identifier Reference Extensions
Informatively referenced by — RFC 4496: Open Pluggable Edge Services (OPES) SMTP Use Cases
Informatively referenced by — RFC 3930: The Protocol versus Document Points of View in Computer Protocols
Informatively referenced by — RFC 3974: SMTP Operational Experience in Mixed IPv4/v6 Environments
Informatively referenced by — RFC 4367: What's in a Name: False Assumptions about DNS Names
Informatively referenced by — RFC 4416: Goals for Internet Messaging to Support Diverse Service Environments
Informatively referenced by — RFC 4902: Integrity, Privacy, and Security in Open Pluggable Edge Services (OPES) for SMTP