RFCs of Relevance to the Email Package Implementation

Base Email RFCs

  • rfc0733 Standard for the Format of ARPA Network Text Messages
  • rfc0822 Standard for the Format of ARPA Internet Text Messages
  • rfc2822 Internet Message Format
  • rfc5322 Internet Message Format

Each of these RFC's obsoletes the one that came before [1], but often reference the earlier RFC. We must also pay attention to the obsolete formats because of the Postel principle

The parser should have two modes (or there should be two parsers): strict and lax. The lax parser (probably with optional logging) would be for everyday use in handling email received from other sources, the strict parser would be for validation and/or data produced by an application itself.

The email package should produce output that strictly conforms to RFC 5322.


  • rfc2045 MIME Part One: Format of Internet Message Bodies
  • rfc2046 MIME Part Two: Media Types
  • rfc2047 MIME Part Three: Message Header Extensions for Non-ASCII Text
  • rfc2048 MIME Part Four: Registration Procedures
  • rfc2049 MIME Part Five: Conformance Criteria and Examples
  • rfc2231 MIME Parameter Value and Encoded Word Extensions: Character Sets, Languages, and Continuations

Specific MIME Content Types

  • rfc1847 Security Multiparts for MIME: Multipart/Signed and Multipart/Encrypted
  • rfc1894 An Extensible Message Format for Delivery of Status Notifications

Mailing List Headers

  • rfc2369 The Use of URLs as Meta-Syntax for Core Mail List Commands and their Transport through Message Header Fields
  • rfc2919 A Structured Field and Namespace for the Identification of Mailing Lists


  • rfc4648 The Base16, Base32, and Base64 Data Encodings

Additional Considerations

An auxiliary module should provide access to the registered IANA data specified by the RFCs. We make use of the data from the mimetimes module, which overlaps with this requirement, so we need to coordinate with the maintainers of that module [2].

One of the sets of IANA data we need to pay attention to is the list of charset identifiers.

We also make use of URLs (rfc3986), and will need to coordinate with the maintainers of urllib for that support.

We also need to be aware of the RFCs that are relevant to the modules that share concerns with the email package and/or are consumers of email package services:


  • RFC2616 Hypertext Transfer Protocol -- HTTP/1.1


  • RFC1036 Standard for Interchange of USENET Messages
  • RFC3977 Network News Transfer Protocol (NNTP)


There are also email extensions that we may want to support. This list is not complete.

  • RFC2111 Content-ID and Message-ID Uniform Resource Locators
  • RFC2112 The MIME Multipart/Related Content-type
[1]In fact, rfc0733 obsoletes several previous RFCs.
[2]mimetypes does not currently have a maintainer listed in maintainers.rst, which may mean we get to tackle it as well.

Email SIG/RelevantRFCs (last edited 2010-01-16 15:18:56 by RDavidMurray)

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