| RFC 1939 - Post Office Protocol (POP) - Version 3: Describes the widely implemented Post Office Protocol (POP), which allows a client to retrieve mail that a server is holding for it. |
| RFC 821 - Simple Mail Transfer Protocol (SMTP): Describes the widely implemented Simple Mail Transfer Protocol (SMTP) designed to transfer mail reliably and efficiently and relay mail across transport service environments. |
| RFC 1123 - Requirements for Internet Hosts - Application and Support: Defines and discusses the requirements for Internet host software and covers the application and support protocols. |
| RFC 1566 - Mail Monitoring MIB: Defines a portion of the Management Information Base (MIB) for use with network management protocols, and extends the basic Network Services Monitoring MIB to allow monitoring of Message Transfer Agents (MTAs). |
| RFC 1869 - SMTP Service Extensions (ESMTP): Defines a framework for extending the SMTP service by defining a means whereby a server can inform a client as to the service extensions it supports. |
| RFC 1893 - Enhanced Mail System Status Codes: Describes the Enhanced Mail System Status Codes, a set of status codes for reporting mail system errors and delivery status notifications. |
| RFC 2033 - Local Mail Transfer Protocol (LMTP): Describes the Local Mail Transfer Protocol (LMTP), for transporting mail into a system where a mail receiver does not manage a queue. |
| RFC 2045 - Multipurpose Internet Mail Extensions (MIME) - Part 1: Specifies the format of Internet message bodies and the various headers used to describe the structure of MIME messages. |
| RFC 2046 - Multipurpose Internet Mail Extensions (MIME) - Part 2: Defines the general structure of the MIME media typing system and defines an initial set of media types. |
| RFC 2047 - Multipurpose Internet Mail Extensions (MIME) - Part 3: Describes extensions to RFC 822 to allow non-US-ASCII text data in Internet mail header fields. |
| RFC 2048 - Multipurpose Internet Mail Extensions (MIME) - Part 4: Specifies various IANA registration procedures for MIME media types, MIME external body access types, and MIME content-transfer-encodings. |
| RFC 2049 - Multipurpose Internet Mail Extensions (MIME) - Part 5: Describes MIME conformance criteria as well as providing some illustrative examples of MIME message formats. |
| RFC 2060 - Internet Message Access Protocol (IMAP) - Version 4 Rev 1: Describes the Internet Message Access Protocol (IMAP), which allows a client to access and manipulate electronic mail messages on a server, and permits manipulation of remote message folders. |
| RFC 2821 - Simple Mail Transfer Protocol: Describes the widely implemented Simple Mail Transfer Protocol (SMTP) designed to transfer mail reliably and efficiently and relay mail across transport service environments. Obsoletes RFC 821, 974, 1869. |
| RFC 822 - Standard for ARPA Internet Text Messages: Specifies the syntax for Internet mail text messages. |
| RFC 947 - Mail Routing and the Domain System: Describes how mail systems on the Internet are expected to route messages based on information from the domain system. |
Classical
